rigorous system examinations called civil services examination cse technical counterpart known engineering services examination ese conducted union public service commission upsc entry state civil services competitive examination conducted every state public service commission senior positions civil service listed named order precedence india japan pakistan pakistan fpsc federal public service commission conducts competitive examination central superior services pakistan civil service posts pakistan inherited system


british raj era indian civil service pakistan federal civil servants serving federal government offices staff selected federal public service commission similarly pakistani provinces select public servants provincial public service commissions federal services quota provincial posts provincial services quota federal services taiwan roc constitution specifies public servant cannot employed without examination employment usually lifelong age retirement europe france civil service france ''fonction publique'' often incorrectly considered include government employees including

Applied science
Public administration
Civil service


employees public corporations sncf public sector employment classified three services state service local service hospital service according government statistics million public sector employees class wikitable sortable style font size style background efefef category central government local government health service total education police defence health social total civil servants germany '''public service germany''' '' ffentlicher dienst'' employed million persons public servants organized hired salaried employees ''arbeitnehmer''


appointed civil servants ''beamte'' soldiers employed public bodies ''k rperschaften des ffentlichen rechts'' counties ''kreise'' states federal government etc addition employees directly employed state another million persons employed state owned enterprises class wikitable sortable style font size style background efefef category federal government regional government municipal government social security total state employees government owned enterprises total ''beamte'' title government employees several centuries german states became standardized group soldiers


conscripted soldiers beamte similar rights judges beamte similar rights public attorneys beamte professors beamte group beamte secure employment amount paid set national pay regulations ''besoldungsordnungen'' beamte prohibited striking ''besch ftigte'' work individual contracts ''beamte'' appointed employed removed public sector service loyalty law '' ffentlich rechtliches dienst und treueverh ltnis'' tasks either done ''besch ftigte'' ''beamte'' however specific tasks official nature


supposed handled ''beamte'' since subject special loyalty obligation ''beamte'' divided four levels ''einfacher dienst'' ordinary civil service corresponding enlisted ranks military largely obsolete ''mittlerer dienst'' medium level civil service corresponding non commissioned officers military ''gehobener dienst'' senior civil service including civil servant positions ''inspektor'' corresponding commissioned officers lieutenant captain military ''h herer dienst'' higher civil service including civil servant positions ''rat'' councillor well academic employees professors corresponding major


military ''gehobener dienst'' ''h herer dienst'' require university education equivalent least bachelor 's master 's degree respectively ireland civil service ireland includes employees departments state excluded government ministers small number paid political advisors well small number core state agencies office revenue commissioners office public works public appointments service organisation irish civil service similar traditional organization british home civil service


indeed grading system irish civil service nearly identical traditional grading system british counterpart ireland public sector employees teachers members country 's police force ''garda och na'' considered civil servants rather described public servants form public service republic ireland russia spain civil service spain ''funci n p blica'' usually considered include employees different levels spanish public administration central government autonomous communities well


municipalities three main categories spanish public positions temporary political posts personal eventual require simple procedure hiring dismissal associated top level executives advisors statutory permanent posts funcionarios de carrera require formal procedure access usually involves competition among candidates whose tenants subject special statutory relationship work employers non statutory permanent posts personal laboral also require formal procedure entry similar procedure required funcionarios de carrera whose tenants subject


normal working conditions laws competitions differ notably among state autonomous communities city councils funcionarios de carrera personal laboral examinations vary difficulty one location another million public employees spain civil servants million non civil servants class wikitable sortable style font size style background efefef category employee type central government regional government municipal university total police civil servants defence civil servants health social civil servants public employees civil


servants public employees total civil servants public employees total recent figures found seat december government rajoy announced civil servants serve minimum working hours per week regardless place kind service ref name politicaelpaiscom ref united kingdom civil service united kingdom includes crown ie central government employees parliamentary employees local government employees public sector employees education nhs considered civil servants police


hm diplomatic service associated separate civil service european union european civil service administers institutions european union largest employer european commission civil servants recruited directly institutions selected competitions set epso official selection office allocated departments known directorates general dgs covering one related policy areas civil service independence autocratic systems government monarchies favour appointments administrative positions basis nepotism patronage favoritism close


relationships political administrative figures early roman emperors example set household slaves freedmen much task administering empire sidelining elected officials continued traditions roman republic political appointment bureaucrats run risk tolerating inefficiency corruption officials feeling secure protection political masters possibly immune prosecution bribe taking song dynasty china standardised competitive examinations basis civil service recruitment promotion th century administrations france britain followed suit agitation spoils


system united states america resulted increasing independence civil service seen important principle modern times governmental structures include civil service commission equivalent whose functions include maintaining work rights civil servants arm 's length potential politicisation political interference compare governance administrative integration stalin 's orgburo see also general civic technology civil service commission civil service examination civil service organisation community service public service continent region civil service reform developing countries eg nigeria congo etc africa nigerian civil service civil service


commission nigeria rivers state civil service asia civil service people 's republic china civil services india civil service early india civil services tamil nadu civil service japan civil service malaysia civil services pakistan civil service commission philippines civil service singapore europe civil service european union civil service germany civil service republic ireland civil service united kingdom civil service commission civil service commission isle man civil service restoration act north america public service canada minister responsible manitoba civil service


united states civil service commission civil service reform civil service reform act civil service reform act oceania australian public service new zealand public service departments south america civil service brazil pay benefits performance related pay pay performance federal government pay performance healthcare pay play performance related pay incentive program united states civil service retirement system merit pay nbsp federal government merit pay pay performance federal government pay performance human resources veterans health administration scandal references reading albrow ''bureaucracy'' armstrong j ''the european administrative elite'' bodde http afeeasiacolumbiaedu chinawh web ideaspdf ''chinese ideas


west'' brownlow louis charles e merriam luther gulick ''report president 's committee administrative management'' coolican michael tradesmen women origins british civil service du gay p ''in praise bureaucracy weber organisation ethics'' du gay p ed ''the values bureaucracy'' hoogenboom ari ''outlawing spoils history civil service reform movement '' mathur pn ''the civil service india study history evolution demand reform'' rao http wwwgsdrcorg docs open csr topicguide pdf ''civil service reform topic guide'' birmingham uk gsdrc university


birmingham http wwwgsdrcorg go topic guides civil service reform schiesl martin ''the politics efficiency municipal administration reform america '' sullivan ceri ''literature public service sublime bureaucracy'' theakston kevin ''the civil service since '' institute contemporary british history van riper paul ''history united states civil service'' white leonard ''introduction study public administration'' white leonard charles h bland walter r sharp fritz morstein marx ''civil service abroad great britain canada france germany'' https webarchiveorg web http wwwquestiacom pmqsta online external links http wwwcivilservicegovuk uk civil service official website http wwwservidorgovbr brazilian civil


servants official website public administration bureaucratic organization


computer science specifically software engineering hardware engineering '''formal methods''' particular kind mathematically rigorous techniques specification development verification software hardware systems ref name butler ref use formal methods software hardware design motivated expectation engineering disciplines performing appropriate mathematical analysis contribute reliability robustness design formal methods best described application fairly broad variety theoretical computer science fundamentals particular logic calculi formal languages automata theory discrete event dynamic system program semantics

Formal science
Computer science
Logic in computer science
Formal methods


option many cases '''level ''' formal development formal verification may used produce program formal manner example proofs properties refinement specification program may undertaken may appropriate high integrity systems involving safety security '''level ''' theorem provers may used undertake fully formal machine checked proofs despite improving tools declining costs expensive practically worthwhile cost mistakes high eg critical parts operating system microprocessor design information


expanded programming language semantics styles formal methods may roughly classified follows denotational semantics meaning system expressed mathematical theory domains proponents methods rely well understood nature domains give meaning system critics point every system may intuitively naturally viewed function operational semantics meaning system expressed sequence actions presumably simpler computational model proponents methods point


simplicity models means expressive clarity critics counter problem semantics delayed defines semantics simpler model axiomatic semantics meaning system expressed terms preconditions postconditions true system performs task respectively proponents note connection classical logic critics note semantics never really describe system ' 'does'' merely true afterwards lightweight formal methods practitioners believe formal methods community overemphasized full formalization


specification design contend expressiveness languages involved well complexity systems modelled make full formalization difficult expensive task alternative various ''lightweight'' formal methods emphasize partial specification focused application proposed examples lightweight approach formal methods include alloy object modelling notation denney 's synthesis aspects z notation use case driven development csk vdm tools uses formal methods applied various points development process specification formal methods may used


give description system developed whatever level detail desired formal description used guide development activities see following sections additionally used verify requirements system developed completely accurately specified formalising system requirements expressing formal language precise unambiguously defined syntax semantics need formal specification systems noted years algol report john backus presented formal notation describing programming language syntax later named


backus normal form renamed backus naur form bnf backus also wrote formal description meaning syntactically valid algol programs n't completed time inclusion report therefore formal treatment semantics legal programs included subsequent paper never appeared development formal development use formal methods integrated part tool supported system development process formal specification produced specification may used guide concrete system developed design process ie realized typically


system implementation satisfies specification formal specification developed specification may used basis proving properties specification hopefully inference developed system sign verification sign verification use formal verification tool highly trusted tool replace traditional verification methods tool may even certified human directed proof sometimes motivation proving correctness system obvious need reassurance correctness system desire understand system


better consequently proofs correctness produced style mathematical proof handwritten typeset using natural language using level informality common proofs good proof one readable understandable human readers critics approaches point ambiguity inherent natural language allows errors undetected proofs often subtle errors present low level details typically overlooked proofs additionally work involved producing good proof requires high level mathematical sophistication expertise automated proof


contrast increasing interest producing proofs correctness systems automated means automated techniques fall three general categories automated theorem proving system attempts produce formal proof scratch given description system set logical axioms set inference rules model checking system verifies certain properties means exhaustive search possible states system could enter execution abstract interpretation system verifies approximation behavioural property program using


fixpoint computation possibly complete lattice representing automated theorem provers require guidance properties interesting enough pursue others work without human intervention model checkers quickly get bogged checking millions uninteresting states given sufficiently abstract model proponents systems argue results greater mathematical certainty human produced proofs since tedious details algorithmically verified training required use systems also less required produce good mathematical proofs hand making techniques accessible


wider variety practitioners critics note systems like oracles make pronouncement truth yet give explanation truth also problem verifying verifier program aids verification unproven may reason doubt soundness produced results modern model checking tools produce proof log detailing step proof making possible perform given suitable tools independent verification main feature abstract interpretation approach provides sound analysis


ie false negatives returned moreover efficiently scalable tuning abstract domain representing property analyzed applying widening operators get fast convergence applications formal methods applied different areas hardware software including routers ethernet switches routing protocols security applications operating system microkernels sel several examples used verify functionality hardware software used dcs ibm used acl theorem prover amd x processor development process intel uses methods verify


hardware firmware permanent software programmed read memory dansk datamatik center used formal methods develop compiler system ada programming language went become long lived commercial product several projects nasa formal methods applied next generation air transportation system unmanned aircraft system integration national airspace system airborne coordinated conflict resolution detection accord b method atelier b used develop safety automatisms various subways installed throughout world alstom siemens also common


criteria certification development system models atmel stmicroelectronics formal verification frequently used hardware well known hardware vendors ibm intel amd many areas hardware intel used fms verify working products parameterized verification cache coherent protocol intel core processor execution engine validation using theorem proving bdds symbolic evaluation optimization intel ia architecture using hol light theorem prover verification high performance dual port gigabit ethernet controller support pci express protocol intel advance


management technology using cadence similarly ibm used formal methods verification power gates registers functional verification ibm power microprocessor software development software development formal methods mathematical approaches solving software hardware problems requirements specification design levels formal methods likely applied safety critical security critical software systems avionics software software safety assurance standards c allows usage formal methods supplementation common criteria mandates formal methods highest levels categorization sequential software examples


specification used build validate application behaviour another approach formal methods software development write specification form logic usually variation first order logic fol directly execute logic though program owl language based description logic dl example also work mapping version english another natural language automatically logic well executing logic directly examples attempto controlled english internet business logic seek control


nets predicative programming process calculi csp lotos calculus raise rebeca modeling language spark ada specification description language tla usl vdm vdm sl vdm z notation model checkers esbmc malpas software static analysis toolset industrial strength model checker used formal proof safety critical systems pat free model checker simulator refinement checker concurrent systems csp extensions eg shared variables arrays fairness spin uppaal organizations apcb bcs facs formal methods europe z user group see also abstract interpretation automated theorem proving design contract formal methods people formal specification formal verification formal system model checking software engineering


specification language references reading jonathan p bowen michael g hinchey ''formal methods'' allen b tucker jr ed ''computer science handbook'' nd edition section xi ''software engineering'' chapter pages nbsp chapman hall crc press association computing machinery hubert garavel editor susanne graf https wwwbsibundde shareddocs de publikationen studien formal methods study study html ''formal methods safe secure computer systems'' bundesamt f r sicherheit der informationstechnik bsi study bonn germany december michael g hinchey jonathan p bowen emil vassev ''formal methods'' philip laplante ed ''encyclopedia software engineering'' taylor francis pages marieke


huisman dilian gurov alexander malkis http arxivorg abs ''formal methods academia industrial practice travel guide'' arxiv jean fran ois monin michael g hinchey ''understanding formal methods'' springer external links http wwwfmeuropeorg formal methods europe fme https formalmethodswikiaorg formal methods wiki http foldocorg formal methods formal methods https foldocorg foldoc archival material https webarchiveorg web http academicresearchmicrosoftcom keyword formal method keyword microsoft academic search via archiveorg https webarchiveorg web http wwwfm industryorg indexphp evidence formal methods uses impact industry evidence formal methods uses impact industry supported http wwwdeploy projecteu deploy project eu fp archiveorg software development philosophies theoretical computer science specification languages


tissue engineering materials science note biomaterial different biological material bone produced biological system additionally care exercised defining biomaterial biocompatible since application specific biomaterial biocompatible suitable one application may biocompatible another ref name schmalzbio ref ref ref cannot extended environmental field people mean material natural origin ref name iupac introduction biomaterials derived either nature synthesized laboratory using variety chemical approaches utilizing metallic components polymers

Applied science
Engineering and technology
Materials Science and Engineering
Biomaterials


ceramics composite materials often used adapted medical application thus comprise whole part living structure biomedical device performs augments replaces natural function functions may relatively passive like used heart valve maybe bioactive interactive functionality hydroxy apatite coated hip implants biomaterials also used every day dental applications surgery drug delivery example construct impregnated pharmaceutical products placed body permits prolonged release drug


extended period time biomaterial may also autograft allograft xenograft used transplant material bioactivity ability engineered biomaterial induce physiological response supportive biomaterial 's function performance known bioactivity commonly bioactive glasses bioactive ceramics term refers ability implanted materials bond well surrounding tissue either osteo conductive osseo productive roles bone implant materials often designed promote bone growth dissolving surrounding body fluid ref name sdha ref thus many biomaterials


self assembly also emerging new strategy chemical synthesis nanotechnology molecular crystals liquid crystals colloids micelles emulsions phase separated polymers thin films self assembled monolayers represent examples types highly ordered structures obtained using techniques distinguishing feature methods self organization structural hierarchy nearly materials could seen hierarchically structured since changes spatial scale bring different mechanisms deformation damage however biological materials hierarchical organization inherent microstructure one first examples history


structural biology early x ray scattering work hierarchical structure hair wool astbury woods bone example collagen building block organic matrix triple helix diameter nbsp nm tropocollagen molecules intercalated mineral phase hydroxyapatite calcium phosphate forming fibrils curl helicoids alternating directions osteons basic building blocks bones volume fraction distribution organic mineral phase another level complexity hydroxyapatite crystals mineral platelets diameter


approximately nbsp nm thickness nbsp nm originally nucleate gaps collagen fibrils similarly hierarchy abalone shell begins nanolevel organic layer thickness nbsp nm layer proceeds single crystals aragonite polymorph caco sub sub consisting bricks dimensions finishing layers approximately nbsp mm mesostructure crabs arthropods whose carapace made mineralized hard component exhibits brittle fracture softer organic component composed primarily chitin brittle component arranged helical pattern


mineral rods diameter contains chitin protein fibrils approximately nbsp nm diameter fibrils made nbsp nm diameter canals link interior exterior shell applications biomaterials used joint replacements bone plates intraocular lenses iols eye surgery bone cement artificial ligaments tendons dental implants tooth fixation blood vessel prostheses heart valves skin repair devices artificial tissue cochlear replacements contact lenses breast implants drug delivery mechanisms sustainable materials vascular grafts stents nerve


body 's tissue grow incorporating valve ref name chemistry textbook ref skin repair time ''' artificial tissue ''' grown patient cells however damage extreme impossible use patient 's cells artificial tissue cells grown difficulty finding scaffold cells grow organize characteristics scaffold must biocompatible cells adhere scaffold mechanically strong biodegradable one successful scaffold copolymer lactic acid glycolic acid ref name chemistry


textbook compatibility biocompatibility related behavior biomaterials various environments various chemical physical conditions term may refer specific properties material without specifying material used example material may elicit little immune response given organism may may able integrate particular cell type tissue immuno informed biomaterials direct immune response rather attempting circumvent process one approach shows promise ambiguity term reflects


decomposition several reactions possible local well systemic include immune response foreign body reaction isolation implant vascular connective tissue possible infection impact lifespan implant graft versus host disease auto alloimmune disorder exhibiting variable clinical course manifest either acute chronic form affecting multiple organs tissues causing serious complications clinical practice transplantation implementation biocompatible materials ref name velnarbunc ref biocompatible plastics commonly used biocompatible materials


biomaterials polymers due inherent flexibility tunable mechanical properties medical devices made plastics often made select including cyclic olefin copolymer coc polycarbonate pc polyetherimide pei medical grade polyvinylchloride pvc polyethersulfone pes polyethylene pe polyetheretherketone peek even polypropylene pp ensure biocompatibility series regulated tests material must pass certified use include united states pharmacopoeia iv usp class iv biological reactivity test international standards organization iso biological evaluation medical devices main objective biocompatibility tests


quantify acute chronic toxicity material determine potential adverse effects use conditions thus tests required given material dependent end use ie blood central nervous system etc mechanical properties addition material certified biocompatible biomaterials must engineered specifically target application within medical device especially important terms mechanical properties govern way given biomaterial behaves one relevant material parameters young modulus ''e'' describes material elastic response stresses


external body depending application may desirable biomaterial high strength resistant failure subjected load however applications may beneficial material low strength careful balance strength stiffness determines robust failure biomaterial device typically elasticity biomaterial increases ultimate tensile strength decrease vice versa one application high strength material undesired neural probes high strength material


used applications tissue always fail device applied load young 's modulus dura mater cerebral tissue order pa happens irreversible damage brain occur thus biomaterial must elastic modulus less equal brain tissue low tensile strength applied load expected ref name saini ref ref name lacourcourtine ref implanted biomaterials may experience temperature fluctuations eg dental implants ductility important material must ductile similar reason tensile strength cannot


high ductility allows material bend without fracture also prevents concentration stresses tissue temperature changes material property toughness also important dental implants well rigid load bearing implant replacement hip joint toughness describes material 's ability deform applied stress without fracturing high toughness allows biomaterial implants last longer within body especially subjected large stress cyclically loaded stresses like stresses applied hip joint running ref name saini medical devices


implanted attached skin another important property requiring consideration flexural rigidity ''d'' flexural rigidity determine well device surface maintain conformal contact tissue surface especially important devices measuring tissue motion strain electrical signals impedance designed stick skin without delaminating epidermal electronics since flexural rigidity depends thickness material ''h'' third power ''h'' sup sup important biomaterial formed thin layers previously mentioned applications conformality


paramount ref name choilee ref biopolymers '''biopolymers''' polymers produced living organisms cellulose starch proteins peptides dna rna examples biopolymers monomeric units respectively sugars amino acids nucleotides cellulose common biopolymer common organic compound earth plant matter cellulose similar manner silk proteinaceous biopolymer garnered tremendous research interest myriad domains including tissue engineering regenerative medicine microfluidics drug delivery see also bionics hydrogel polymeric surface surface modification


biomaterials proteins synthetic biodegradable polymer list biomaterials footnotes references external links http jbasagepubcom journal biomaterials applications http wwwcrebupcedu creb biomedical engineering research centre http wwwmpikgmpgde biomaterials department biomaterials max planck institute colloids interfaces potsdam golm germany http wwwchemelotcom open innovation campus biomaterials biomolecules sv biomassa


singing girls '''singing''' act producing musical sounds voice person sings called '' 'singer''' '''vocalist''' jazz popular music ref name ref singers perform music arias recitatives songs etc sung without accompaniment musical instruments singing often done ensemble musicians choir singers band instrumentalists singers may perform soloists accompanied anything single instrument art song jazz styles symphony orchestra big band different singing styles

Humanities
Performing arts
Music
Singing


include art music opera chinese opera indian music religious music styles gospel traditional music styles world music jazz blues ghazal popular music styles pop rock electronic dance music singing formal informal arranged improvised may done form religious devotion hobby source pleasure comfort ritual part music education profession excellence singing requires time dedication instruction regular practice practice done regularly sounds become clearer stronger ref


tube wind instrument tongue together palate teeth lips articulate impose consonants vowels amplified sound though four mechanisms function independently nevertheless coordinated establishment vocal technique made interact upon one another passive breathing air inhaled diaphragm exhalation occurs without effort exhalation may aided abdominal internal intercostal lower pelvis pelvic muscles inhalation aided use external intercostals scalenes sternocleidomastoid muscles pitch altered vocal


cords lips closed called humming sound individual 's singing voice entirely unique actual shape size individual 's vocal cords also due size shape rest person 's body humans vocal folds loosen tighten change thickness breath transferred varying pressures shape chest neck position tongue tightness otherwise unrelated muscles altered one actions results


name vennard polka dots ref primary method singers accomplish use singer 's formant shown match particularly well sensitive part ear 's frequency range also shown powerful voice may achieved fatter fluid like vocal fold mucosa pliable mucosa efficient transfer energy airflow vocal folds vocal classification european classical music opera voices treated like musical instruments composers write vocal music must


understanding skills talents vocal properties singers '''voice classification''' process human singing voices evaluated thereby designated voice types qualities include limited vocal range vocal weight vocal tessitura vocal timbre vocal transition points breaks lifts within voice considerations physical characteristics speech level scientific testing vocal registration ref name shewan ref science behind voice classification developed within european classical music slow adapting modern forms singing voice classification often used within opera


like coloratura facility vocal weight differentiate voices ref name mckinney within choral music singers' voices divided solely basis vocal range choral music commonly divides vocal parts high low voices within sex satb soprano alto tenor bass result typical choral situation gives many opportunities misclassification occur ref name mckinney since people medium voices must assigned part either high low mezzo soprano must sing soprano alto baritone must


sing tenor bass either option present problems singer singers fewer dangers singing low singing high ref name smith ref within contemporary forms music sometimes referred contemporary commercial music singers classified style music sing jazz pop blues soul country folk rock styles currently authoritative voice classification system within non classical music attempts made adopt classical voice type terms forms singing attempts met controversy development


voice categorizations made understanding singer would using classical vocal technique within specified range using unamplified microphones vocal production since contemporary musicians use different vocal techniques microphones forced fit specific vocal role applying terms soprano tenor baritone etc misleading even inaccurate ref name appelman ref vocal registration ''vocal registration'' refers system vocal registers within voice register voice particular series tones produced vibratory pattern vocal folds possessing


quality registers originate laryngeal function occur vocal folds capable producing several different vibratory patterns vibratory patterns appears within particular range pitches produces certain characteristic sounds ref name large ref occurrence registers also attributed effects acoustic interaction vocal fold oscillation vocal tract term register somewhat confusing encompasses several aspects voice term register used refer following ref name mckinney ref particular part vocal range


upper middle lower registers resonance area chest voice head voice phonatory process phonation process producing vocal sound vibration vocal folds turn modified resonance vocal tract certain vocal timbre vocal color region voice defined delimited vocal breaks linguistics '' 'register language''' language combines tone vowel phonation single phonological system within speech pathology term vocal register three constituent elements certain vibratory


related resonation process include amplification enrichment enlargement improvement intensification prolongation although strictly scientific usage acoustic authorities would question main point drawn terms singer speaker result resonation make better sound ref name mckinney seven areas may listed possible vocal resonators sequence lowest within body highest areas chest tracheal tree larynx pharynx oral cavity nasal cavity


sinuses ref name greene ref chest voice head voice ''chest voice'' ''head voice'' terms used within vocal music use terms varies widely within vocal pedagogical circles currently one consistent opinion among vocal music professionals regards terms chest voice used relation particular part vocal range type vocal register vocal resonance area specific vocal timbre ref name mckinney head voice used relation particular part vocal range type vocal


register vocal resonance area ref name mckinney men head voice commonly referred falsetto history development first recorded mention terms chest voice head voice around th century distinguished throat voice pectoris guttoris capitis time likely head voice referred falsetto register writers johannes de garlandia jerome moravia ref name groveone ref terms later adopted within bel canto italian opera singing method chest voice identified lowest


head voice highest three vocal registers chest passagio head registers ref name stark approach still taught vocal pedagogists today another current popular approach based bel canto model divide men women 's voices three registers men 's voices divided chest register head register falsetto register woman 's voices chest register middle register head register pedagogists teach head register vocal technique used singing describe resonance felt singer 's head ref name headv ref however knowledge


physiology increased past two hundred years understanding physical process singing vocal production result many vocal pedagogists ralph appelman indiana university william vennard university southern california redefined even abandoned use terms chest voice head voice ref name stark particular use terms ''chest register'' ''head register'' become controversial since vocal registration commonly seen today product laryngeal function unrelated physiology chest lungs


head reason many vocal pedagogists argue meaningless speak registers produced chest head argue vibratory sensations felt areas resonance phenomena described terms related vocal resonance registers vocal pedagogists prefer terms ''chest voice'' ''head voice'' term register view believes problems people identify register problems really problems resonance adjustment view also alignment views academic fields study


vocal registration including speech pathology phonetics linguistics although methods still use current vocal pedagogical practice tends adopt newer scientific view also vocal pedagogists take ideas viewpoints ref name mckinney contemporary use term chest voice often refers specific kind vocal coloration vocal timbre classical singing use limited entirely lower part modal register normal voice within forms singing chest voice often applied throughout modal register chest timbre add wonderful array


sounds singer 's vocal interpretive palette ref name miller ref however use overly strong chest voice higher registers attempt hit higher notes chest lead forcing forcing lead consequently vocal deterioration ref name oxforddictoperaone ref vocal pedagogy ercole de' roberti concert c '''vocal pedagogy''' study teaching singing art science vocal pedagogy long history began ancient greece continues develop change today professions practice art science vocal pedagogy include vocal coaches choral directors


vocal music educators opera directors teachers singing vocal pedagogy concepts part developing proper vocal technique typical areas study include following ref name titze ref ref name titze ref anatomy physiology relates physical process singing vocal health voice disorders related singing breathing air support singing phonation vocal resonation voice projection vocal registration particular series tones produced vibratory pattern vocal folds possessing quality originate laryngeal function vibratory patterns appears within particular range


pitches produces certain characteristic sounds voice classification vocal styles classical singers includes styles ranging lieder opera pop singers styles include belted blues ballads jazz singers styles include swing ballads scatting techniques used styles sostenuto legato range extension tone quality vibrato coloratura vocal technique real time mri vocal tract singing singing done proper vocal technique integrated coordinated act effectively coordinates physical processes singing four physical processes involved producing


vocal sound respiration phonation resonation articulation processes occur following sequence breath taken sound initiated larynx vocal resonators receive sound influence articulators shape sound recognizable units although four processes often considered separately studied actual practice merge one coordinated function effective singer speaker one rarely reminded process involved mind body coordinated one perceives resulting unified function many vocal problems result


lack coordination within process ref name appelman since singing coordinated act difficult discuss individual technical areas processes without relating others example phonation comes perspective connected respiration articulators affect resonance resonators affect vocal folds vocal folds affect breath control forth vocal problems often result breakdown one part coordinated process causes voice teachers frequently focus intensively one area process student issue


resolved however areas art singing much result coordinated functions hard discuss traditional heading like phonation resonation articulation respiration voice student become aware physical processes make act singing processes function student begins task trying coordinate inevitably students teachers become concerned one area technique another various processes may progress different rates resulting imbalance lack


coordination areas vocal technique seem depend strongly student 's ability coordinate various functions ref name mckinney extending vocal range maximum potential developing consistent vocal production consistent tone quality developing flexibility agility achieving balanced vibrato blend chest head voice every note range developing singing voice singing skill requires highly developed muscle reflexes singing require much muscle strength require high degree muscle


diaphragm improves sleep benefits cardio function improving aerobic capacity relaxes overall muscle tension improves posture opens sinuses respiratory tubes training could help decrease snoring releases endorphins boosts immune system helps improve physical balance people affected illnesses parkinson 's disease extending vocal range important goal vocal development learn sing natural limits one 's vocal range without obvious distracting changes quality technique vocal pedagogists teach singer achieve


goal physical processes involved singing laryngeal action breath support resonance adjustment articulatory movement effectively working together vocal pedagogists believe coordinating processes establishing good vocal habits comfortable tessitura voice slowly expanding range ref name vennard three factors significantly affect ability sing higher lower ''energy'' factor nbsp energy several connotations refers total response body making sound dynamic relationship breathing


beginning yawn ' 'depth'' factor nbsp depth two connotations refers actual physical sensations depth body vocal mechanism mental concepts depth related tone quality mckinney says three factors expressed three basic rules sing higher must use energy sing lower must use less sing higher must use space sing lower must use less sing higher must use depth sing


lower must use less ref name mckinney posture singing process functions best certain physical conditions body put place ability move air body freely obtain needed quantity air seriously affected posture various parts breathing mechanism sunken chest position limit capacity lungs tense abdominal wall inhibit downward travel diaphragm good posture allows breathing mechanism fulfill basic function efficiently without


undue expenditure energy good posture also makes easier initiate phonation tune resonators proper alignment prevents unnecessary tension body vocal pedagogists also noted singers assume good posture often provides greater sense self assurance poise performing audiences also tend respond better singers good posture habitual good posture also ultimately improves overall health body enabling better blood circulation preventing fatigue stress body ref name vennard eight components ideal singing posture


feet slightly apart legs straight knees slightly bent hips facing straight forward spine aligned abdomen flat chest comfortably forward shoulders back head facing straight forward breathing breath support natural breathing three stages breathing period breathing period resting recovery period stages usually consciously controlled within singing four stages breathing breathing period inhalation setting controls period suspension controlled exhalation period phonation recovery period stages must conscious control


singer become conditioned reflexes many singers abandon conscious controls reflexes fully conditioned ultimately leads chronic vocal problems ref name sundberg ref vibrato vibrato technique sustained note wavers quickly consistently higher lower pitch giving note slight quaver vibrato pulse wave sustained tone vibrato occurs naturally result proper breath support relaxed vocal apparatus studies shown vibrato result neuromuscular tremor vocal folds


max schoen first make comparison vibrato tremor due change amplitude lack automatic control half rate normal muscular discharge ref name stark ref singers use vibrato means expression many successful artists sing deep rich vibrato extended vocal technique extended vocal techniques include rapping screaming growling overtones falsetto yodeling belting use vocal fry register using sound reinforcement systems among others sound reinforcement system combination microphones signal processors amplifiers loudspeakers combination units may


also use reverb echo chambers auto tune among devices vocal music '''vocal music''' music performed one singers typically called songs may performed without instrumental accompaniment singing provides main focus piece vocal music probably oldest form music since require instrument equipment besides voice musical cultures form vocal music many long standing singing traditions throughout world 's cultures music employs singing feature prominently


generally considered instrumental music example blues rock songs may short simple call response chorus emphasis song instrumental melodies improvisation vocal music typically features sung words called lyrics although notable examples vocal music performed using non linguistic syllables noises sometimes musical onomatopoeia short piece vocal music lyrics broadly termed song although classical music terms aria typically used genres vocal music berwald hall vocal music written many different


backing singer sings backup vocals harmony song backing vocalists sing usually parts song often singing song 's refrain humming background exception five part gospel cappella music lead highest five voices sings descant melody artists may sing lead backing vocals audio recordings overlapping recorded vocal tracks popular music includes range vocal styles hip hop uses rapping rhythmic delivery rhymes


rhythmic speech beat without accompaniment types rapping consist mostly entirely speech chanting like jamaican toasting types rapping performers may interpolate short sung half sung passages blues singing based use blue notes notes sung slightly lower pitch major scale expressive purposes heavy metal hardcore punk subgenres vocal styles include techniques screams shouts unusual sounds death growl one difference live performances popular classical genres


sounds humming mixing half sung sung tones well performers use microphone 's response patterns create effects bringing mic close mouth get enhanced bass response case hip hop beatboxers plosive p b sounds mic create percussive effects controversy arose widespread use electronic auto tune pitch correction devices recorded live popular music vocals controversy also arisen due cases pop singers found lip syncing pre recorded recording


vocal performance case controversial act milli vanilli lip syncing tracks recorded uncredited singers bands use backup singers sing stage common backup singers popular music roles many rock metal bands musicians backup vocals also play instruments rhythm guitar electric bass drums latin afro cuban groups backup singers may play percussion instruments shakers singing pop hip hop groups musical theater backup singers may


musical skills excellent voice ability work people sense showmanship drama additionally singers need ambition drive continually study improve ref name careers ref professional singers continue seek vocal coaching hone skills extend range learn new styles well aspiring singers need gain specialized skills vocal techniques used interpret songs learn vocal literature chosen style music gain skills choral music techniques sight singing memorizing songs vocal exercises singers learn


competition begins field contestants narrowed week week winner chosen move next round contestants' fate determined vote viewers ''the voice'' another singing competition program similar ''american idol'' contestants audition front panel judges however judges' chairs faced towards audience performance coaches interested artist press button signifying want coach auditions conclude coaches team artists competition


begins coaches mentor artists compete find best singer well known singing competitions include ''the x factor'' ''america 's got talent'' ''rising star'' ''the sing off'' different example singing competition ''do n't forget lyrics '' show 's contestants compete win cash prizes correctly recalling song lyrics variety genres show contrasts many music based game shows artistic talent ability sing dance aesthetically pleasing way irrelevant contestants' chances winning words one


commercials prior first airing n't sing well sing right similar vein ''the singing bee'' combines karaoke singing spelling bee style competition show featuring contestants trying remember lyrics popular songs another example singing competition international voice competition boris martinovich named american opera singer bass baritone boris martinovich competition requires participants demonstrate classical opera singing technique known ''bel canto'' health benefits scientific studies suggest singing positive effects


people 's health preliminary study based self reported data survey students participating choral singing found perceived benefits including increased lung capacity improved mood stress reduction well perceived social spiritual benefits ref name clift ref however one much older study lung capacity compared professional vocal training without failed back claims increased lung capacity ref name heller ref singing may positively influence immune system reduction stress one study found singing listening choral music reduces level stress hormones increases


others cited people sing likely happy singing elevates levels neurotransmitters associated pleasure well humans long prehistory music especially singing written language stories passed song song often memorable also evidence music singing may evolved humans language levitin ''this brain music'' argues music may activity prepared pre human ancestors speech communication singing might helped


species refine motor skills paving way development exquisitely fine muscle control required vocal speech ref name brain music ref hand cites pinker argued language adaptation music spandrel evolutionary accident piggybacking language ref name brain music studies found evidence suggesting mental well physical benefits singing conducting study members choir three different points one year three themes suggested three areas benefits social impact connectedness


others personal impact positive emotions self perception etc functional outcomes health benefits choir findings showed sense well associated singing uplifting mood participants releasing endorphins brain many singers also reported singing helped regulate stress relax allowing deal better daily lives social perspective approval audience interaction choir members positive manner also beneficial singing beneficial pregnant mothers giving another medium communication newborns


mothers one study reported feelings love affection singing unborn children also reported feeling relaxed ever stressful pregnancy song nostalgic significance reminding singer past momentarily transport allowing focus singing embrace activity escape daily lives problems effect body recent study tenovus cancer care found singing choir one hour boosts levels immune proteins cancer patients positive overall


article ''toronto star'' everyone sing even musically talented health benefits singing lowers blood pressure releasing pent emotions boosting relaxation reminding happy times also allows singers breathe easily patients lung disease chronic pulmonary disease experience relief symptoms singing two times week addition breathing related illness singing also numerous benefits stroke victims comes relearning ability speak communicate singing thoughts singing activates


right side brain left side cannot function left side area brain responsible speech easy see singing excellent alternative speech victim heals singing language every spoken language natural non natural language intrinsic musicality affects singing means pitch phrasing accent neurological aspects much research done recently link music language especially singing becoming increasingly clear two processes much


alike yet also different levitin describes beginning eardrum sound waves translated pitch tonotopic map shortly thereafter speech music probably diverge separate processing circuits ref name brain music evidence neural circuits used music language may start infants undifferentiated several areas brain used language music example brodmann area implicated processing syntax oral sign languages well musical syntax semantic aspects


language levitin recounts certain studies listening music attending syntactic features similar syntactic processes language activated part brain addition musical syntax localized areas adjacent overlapping regions process speech syntax broca 's area regions involved musical semantics appear localized near wernicke 's area broca 's area wernicke 's area important steps language processing production singing shown help stroke victims recover speech according neurologist gottfried schlaug


corresponding area speech resides left hemisphere right side brain casually known singing center teaching stroke victims sing words help train area brain speech support theory levitin asserts regional specificity speech may temporary processing centers important mental functions actually move regions trauma brain damage ref name brain music thus right hemisphere brain singing center may


retrained help produce speech accents singing speaking dialect accent person may differ greatly general singing accent person uses singing people sing generally use accent neutral accent used style music singing rather regional accent dialect style music popular center region style influence singing accent person come example english language british singers rock


popular music often sing american accent neutral accent instead english accent singing animals scholars agree singing strongly present many different species wide dispersal singing behavior among different animal species like birds gibbons whales many others strongly suggests singing appeared independently different species currently species animals known sing least singing species demonstrate ability learn songs improvise even compose new melodies animal species singing group activity see


example singing gibbon families singing animals herders scandinavia use songs known kulning call livestock mongolian herders use species specific songs encourage bonding animals newborn offspring see also list multilingual bands artists sign singing art music cappella aria bel canto chanson chiaroscuro music child singer choral music fach group singing opera overtone singing recitative singer songwriter sprechgesang throat singing voice pedagogy voice projection voice type yodeling winsingad music beat boxing belt music death growl humming isicathamiya kulning lead vocalist mbube rapping


screaming music vocoder physiology ''n'' acylethanolamine nae references reading blackwood alan ''the performing world singer'' london hamish hamilton p amply ill mostly photos reid cornelius ''a dictionary vocal terminology analysis'' new york j patelson music house external links http wwwlawrenceedu fast koopmajo briefhtml brief history singing https webarchiveorg web http wwwcanterburyacuk research centres sdhr researchprojects completedpojects singingandhealthaspx singing health systematic mapping review non clinical research occupations music music performance articles containing video clips


''' ''' morula ''' ''' blastula ''' ''' blastula ''' ''' gastrula blastopore '''orange''' ectoderm '' 'red''' endoderm '''embryology''' greek ''embryon'' unborn embryo '' logia'' branch biology studies prenatal development gametes sex cells fertilization development embryos fetuses additionally embryology encompasses study congenital disorders occur birth known teratology early embryology proposed marcello malpighi known preformationism theory organisms develop pre existing miniature versions aristotle proposed theory accepted epigenesis epigenesis

Natural science
Biology
Developmental biology
Embryology


idea organisms develop seed egg sequence steps modern embryology developed work karl ernst von baer though accurate observations made italy anatomists aldrovandi leonardo da vinci renaissance comparative embryology preformationism epigenesis tiny person ''homunculus'' inside sperm drawn nicolaas hartsoeker recently th century prevailing notion western human embryology preformation idea semen contains embryo preformed miniature infant ''homunculus''


simply becomes larger development competing explanation embryonic development ''epigenesis'' originally proposed years earlier aristotle much early embryology came work italian anatomists aldrovandi aranzio leonardo da vinci marcello malpighi gabriele falloppio girolamo cardano emilio parisano fortunio liceti stefano lorenzini spallanzani enrico sertoli mauro rusc ni according epigenesis form animal emerges gradually relatively formless egg microscopy improved th century biologists could see embryos took shape series progressive steps epigenesis displaced preformation favored explanation among embryologists ''''''clevage''''''


cleavage beginning steps developing embryo cleavage refers many mitotic divisions occur egg fertilized sperm ways cells divide specific certain types animals may many forms holoblastic holoblastic cleavage complete division cells holoblastic cleavage radial see radial cleavage spiral see spiral cleavage bilateral see bilateral cleavage rotational see rotational cleavage holoblastic cleavage entire egg divide become embryo whereas meroblastic cleavage cells become embryo


others yolk sac meroblastic meroblastic cleavage incomplete division cells division furrow protrude yolky region cells impede membrane formation causes incomplete separation cells meroblastic cleavage bilateral see bilateral cleavage discoidal see discoidal cleavage centrolecithal see centrolecithal basal phyla animals belong basal phyla holoblastic radial cleavage results radial symmetry see symmetry biology cleavage central axis divisions rotate basal phyla also


one two embryonic cell layers compared three bilateral animals endoderm mesoderm ectoderm bilaterians bilateral animals cleavage either holoblastic meroblastic depending species gastrulation blastula develops one two ways divide whole animal kingdom two halves see ''embryological origins mouth anus'' blastula first pore blastopore becomes mouth animal protostome blastopore becomes anus deuterostome protostomes include invertebrate animals insects worms


molluscs deuterostomes include vertebrates due course blastula changes differentiated structure called gastrula soon gastrula formed three distinct layers cells germ layers bodily organs tissues develop germ layers innermost layer endoderm give rise digestive organs gills lungs swim bladder present kidneys nephrites middle layer mesoderm gives rise muscles skeleton blood system outer layer cells ectoderm gives rise


nervous system including brain skin carapace hair bristles scales ''drosophila melanogaster'' fruit fly drosophila used developmental model many years studies conducted discovered many useful aspects development apply fruit flies species well outlined process leads cell tissue differentiation maternal effect genes help define anterior posterior axis using bicoid gene nanos gene gap genes establish broad segments embryo pair rule genes define segments embryo


zygote implants uterus wall end eighth week conception beyond eighth week conception tenth week pregnancy developing human called fetus evolutionary embryology evolutionary embryology expansion comparative embryology ideas charles darwin similarly karl ernst von baer 's principles explained many species often appear similar one another early developmental stages darwin argued relationship groups determined based upon common embryonic larval structures von baer 's principles general features


appear earlier development specialized features specialized characters develop general ones embryo given species never resembles adult form lower one embryo given species resemble embryonic form lower one ref name ref using darwin 's theory evolutionary embryologists since able distinguish homologous analogous structures varying species homologous structures similarities derived common ancestor human arm bat wings analogous structures appear


similar common ancestral derivation ref name origins modern embryology birth modern embryology observation mammalian ovum karl ernst von baer clear scientific understanding embryology late ultrasound first used uterine scanning true developmental chronology human fetus available karl ernst von baer along heinz christian pander also proposed germ layer theory development helped explain embryo developed progressive steps part explanation explored


child term medical embryology medical embryology used widely detect abnormalities birth babies born observable abnormality medical embryology explores different ways stages abnormalities appear ref name genetically derived abnormalities referred malformations multiple malformations considered syndrome abnormalities appear due outside contributors disruptions outside contributors causing disruptions known teratogens common teratogens alcohol retinoic acid ionizing radiation hyperthermic stress vertebrate invertebrate embryology many principles


embryology apply invertebrates well vertebrates therefore study invertebrate embryology advanced study vertebrate embryology however many differences well example numerous invertebrate species release larva development complete end larval period animal first time comes resemble adult similar parent parents although invertebrate embryology similar ways different invertebrate animals also countless variations instance spiders proceed directly egg adult form many insects develop least one


larval stage decades number called normal staging tables produced embryology particular species mainly focussing external developmental characters variation developmental progress makes comparison among species difficult character based standard event system developed documents differences allows phylogenetic comparisons among species birth developmental biology dna helical structure unraveled increasing knowledge field molecular biology developmental biology emerged field study attempts correlate genes morphological change tries


determine genes responsible morphological change takes place embryo genes regulated gallery file leonardo da vinci studies foetus wombjpg human embryos leonardo da vinci file weeks pregnantpng human embryo six weeks gestational age file daymouseembjpg histological film day mouse embryo gallery today human embryology taught cornerstone subject medical schools well biology zoology programs undergraduate graduate level history ancient egypt study embryology long pedigree knowledge placenta goes back


least ancient egypt placenta viewed seat soul even egyptian official held title ''opener kings placenta'' furthermore one egyptian text time akhenaten claims human originates egg grows women ancient india variety conceptions embryology appeared ancient asia advanced understanding embryological process known ancient india descriptions amniotic membrane appear bhagavad gita bhagavata purana sushruta samhita example sushruta samhita claims


embryo emerges semen blood turn find origins chyle third month differentiation body parts arms leg head occurs followed fourth month development heart thorax abdomen sixth month hair bones sinews nails veins develop eighth month vital force ''ojas'' drawn mother developing child father donates hard parts body developing fetus whereas soft parts come


mother aristotle sushruta samhita compares developing embryo clotting milk cheese claims conditions heat result seven layers skin formed around fetus creamy layers cheese form milk one upanishads known ''garbhopanisa '' states embryo like water first night seven nights like bubble end half month becomes ball end month hardened two months head formed


indian medical tradition ayurveda also conceptions embryology antiquity dalhana medieval commentator sushruta samhita also describes embryological development dalhana claims first month fetus jelly like form whereas cold heat cause change hardness second month limb differentiation occurs third four months intelligence even later ancient greece pre socratic philosophers many pre socratic philosophers recorded opinions different aspects embryology although bias description views later authors aristotle


according empedocles whose views described plutarch st century ad lived th century bc embryo derives receives blood four vessels two arteries two veins also held sinews originating equal mixtures earth air said men begin form within first month finished within fifty days asclepiades agreed men formed within fifty days believed women took full two months fully knit one observation variously attributed either anaxagoras clazomenae


dissection one idea lasted long time first claimed parmenides connection right side body male embryo left side body female embryo according democritus epicurus fetus nourished mouth inside mother comparable teats supply nourishment within mother 's body fetus discussion various views regarding long takes specific parts embryo form appear anonymous document known ''nutriment'' greek


discussions embryology often tried answer several questions one question regarded whether male seed developed embryo within female womb whether male female seed made contribution developing embryo difficulty one seed theorists confronted explain maternal resemblance progeny one issue two seed theorists confronted female seed needed male already seed one common solution problem assert female seed either inferior inactive


another question answer origin seed one theory answer known encephalomyelogenic theory stated seed originated brain bone marrow later came pangenesis asserted seed drawn whole body order explain general resemblance body offspring later hematogenous theory developed asserted seed drawn blood third question regarded form progeny existed seed prior developing embryo fetus according preformationists


body progeny already existed pre existing undeveloped form seed three variants preformationism homoiomerous preformationism anhomoiomerous preformationism homuncular preformationism according first homoiomerous parts body eg humors bone already exist pre formed seed second held anhomoiomerous parts pre formed finally third view held whole already unified organic thing preformationism view according epigenesists parts embryo successively form conception takes place ref name wilb james wilberding plato 's embryology early science medicine


ref hippocrates well known early ideas embryology come hippocrates hippocratic corpus discussion embryo usually given context discussing obstetrics pregnancy childbirth relevant hippocratic texts embryology include ''regimen acute diseases'' ''on semen'' ''on development child'' hippocrates claimed development embryo put motion fire nourishment comes food breath introduced mother outer layer embryo solidifies fire within consumes humidity makes


way development bone nerve fire innermost part becomes belly air channels developed order route nourishment enclosed fire also helps form veins allows circulation description hippocrates aims describing causes development rather describing develops hippocrates also develops views similar preformationism claims parts embryo simultaneously develop hippocrates also believed maternal blood nourishes embryo blood flows coagulates help form flesh fetus idea derived


observation menstrual blood ceases pregnancy hippocrates took imply redirected fetal development hippocrates also claimed flesh differentiates different organs body hippocrates saw analogous experiment mixture substances placed water differentiate different layers comparing seed embryo hippocrates compared stalk umbilical cord aristotle embryological discussion appears writings aristotle 's predecessor plato especially ''timaeus'' one views bone marrow acted seedbed


soul seed embryo developed though explain development proceeded scholars also continue debate views held various aspects embryology ref name wilb however much voluminous discussion subject comes writings aristotle especially appears ''on generation animals'' ideas related embryology also appear ''history animals'' ''on parts animals'' ''on respiration'' ''on motion animals'' means know aristotle studied embryology likely


melanesians held fetus solely product female contribution aristotle believe external influences development embryo hippocrates aristotle believed new parts body developed time rather forming immediately developing also considered whether new part derives previously formed part develops independently previously formed part basis different parts body resemble decided favor latter view also described development


fetal parts terms mechanical automatic processes terms development embryo says begins liquid like state material secreted female combines semen male surface begins solidify interacts processes heating cooling first part body differentiate heart aristotle many contemporaries believed location reason thinking aristotle claimed vessels join uterus order supply nourishment developing fetus


solid parts fetus cool lose moisture heat turn nails horns hoofs beaks etc internal heat dries away moisture forms sinews bones skin results drying flesh aristotle also describes development birds eggs length described embryonic development dolphins sharks many animals aristotle singularly wrote embryology pre modern author influence subsequent discussion subject many centuries immense introducing subject forms classification comparative


method various animals discussion development sexual characteristics compared development embryo mechanistic processes forth later greek embryology reportedly stoics claimed parts body formed embryological development epicureans claimed fetus nourished either amniotic fluid blood male female supply material development fetus according writings tertullian herophilus th century bc described ovaries fallopian tubes past already described aristotle


also dissected embryos one advance herophilus made conceptions individuals aristotle brain center intellect rather heart though part greek tradition job formation embryo likened curdling milk cheese described aristotle whereas needham sees statement job part aristotelian tradition others see evidence milk analogy predates aristotelian greek tradition originates jewish circles ref name kot samuel kottek embryology talmudic midrashic literature journal


history biology ref addition wisdom solomon also embryo formed menstrual blood soranus ephesus also wrote texts embryology went use long time rabbinic texts discuss embryology female greek writer named cleopatra contemporary galen soranus said claimed male fetus complete days whereas female fetus complete days various texts less importance also appear describe various aspects embryology though without making much progress aristotle


plutarch chapter one works titled whether hen egg discussion embryological tradition also appears many neoplatonic traditions next aristotle impactful important greek writer biology galen pergamum works transmitted throughout middle ages galen discusses understanding embryology two texts ''on natural faculties'' ''on formation foetus'' additional text spuriously attributed galen known ''on question whether embryo animal'' galen


described embryological development four stages first stage semen predominates second stage embryo filled blood third stage main outlines organs developed various parts remain undeveloped fourth stage formation complete reached stage call child galen described processes played role furthering development embryo warming drying cooling combinations thereof development plays form life embryo also moves like plant


animal analogy root umbilical cord made galen claimed embryo forms menstrual blood experimental analogy cut vein animal allow blood flow mildly heated water sort coagulation observed gave detailed descriptions position umbilical cord relative veins patristics question embryology discussed among number patristic authors largely terms theological questions whether fetus value


writings origen condemned second origenist crises defending ''prohyparxis'' usually appealed platonic notion eternally moving soul defending second position also appealed plato rejected notion eternality soul finally appealing third position appealed aristotle scripture aristotelian notions included progression development soul initial plant like soul sensitive soul found animals allows movement perception finally formation rational soul found


fully formed human furthermore scriptural texts seen implying formation soul temporally formation body namely genesis exodus zachariah ''de hominis opificio'' gregory nyssa aristotle 's triparitate notion soul accepted gregory also held rational soul present conception theodoret argued based genesis exodus embryo ensouled body fully formed based exodus zachariah monophysite philoxenus mabbug claimed soul created


body forty days conception ''de opificio mundi'' christian philosopher john philoponus claimed soul formed body later still author leontius held body soul created simultaneously though also possible held soul pre existed body ref name dirk dirk krausmuller christology intersects embryology viewpoints nestorian monophysite chalcedonian authors sixth tenth centuries byzantinische zeitschrift ref monophysites chalcedonians seemed compelled accepting ' 'synhyparxis'' case jesus view incarnation


christ resulted one hypostasis one nature whereas nestorians claimed christ like us must soul formed formation body per hebrews christ like us ways sin hand leontinus dismissed relevance hebrews basis christ differed us sinfulness also conception without semen making ' 'synhyparxis'' another christ 's supernatural feats felt comfortable holding view belief human nature jesus separate divine hypostasis nestorians


touch topic support ' 'synhyparxis'' debate among groups remains lively still divided similar sectarian grounds patriarch timothy argued word first united body later soul cited john claiming basis word became flesh first human first jacob edessa rejected ''prohyparxis'' origen defended ''methyparxis'' believed made soul ontologically inferior made body moses bar kepha claimed christological reasons monophysite


' 'synhyparxis'' acceptable claimed genesis temporal sequence exodus regards formation body soul relevant argue ''methyparxis'' reasoned body soul present death end must correspond also beginning conception must also body soul together ref name dirk embryology jewish tradition many jewish authors also discussed notions embryology especially appear talmud much embryological data talmud


talmud even greater detail midrash womb woman full retained blood comes forth area menstruation lord comes drop white matter falls embryo created compared milk put vessel add lab ferment drug herb coagulates stands still milk remains liquid ref name kot talmud sages held two seeds participated formation


jewish tradition accepted male female contributed parts formation fetus th century medieval commentator nachmanides example rejected female contribution tractate hullin talmud whether organs child resemble closely mother father said depend one contribute matter embryo depending child rabbi ishmael sages said disagreed one matter agreed male embryo developed st day disagreed whether case


female embryo believed female embryo complete later whereas others held finished time ancient jewish authors associated abortion homicide josephus philo alexandria st century talmudic texts discuss magical influences development embryo one text claims one sleeps bed pointed north south male child according nachmanides child born cold drop semen foolish one born warm


drop semen passionate irascible one born semen drop medium temperature clever level headed talmudic discussions follow hippocratic claims child born eighth month could survive whereas others follow aristotle claiming sometimes could survive one text even says survival possible seventh month eighth talmudic embryology various aspects follows greek discourses especially hippocrates aristotle areas makes novel statements subject ref name kot embryology islamic tradition passing reference


embryological notions also appear qur'an development embryo proceeds four stages drop blood clot partially developed stage fully developed child notion clay turning flesh seen analogous text theodoret describes process four stages development qur'an similar four stages embryological development described galen early th century sergius reshaina devoted translation greek medical texts syriac became


important figure process included translations relevant embryological texts galen anurshirvan founded medical school southern mesopotamian city gundeshapur known academy gondishapur also acted medium transmission reception development notions greek medicine factors helped transmission greek notions embryology found galen enter arabian milieu similar embryonic descriptions also appear syriac jacob serugh 's letter archdeacon mar julian ref name kour embryological discussions also appear


islamic legal tradition see also abortion embryogenesis embryonic differentiation waves embryology digestive system body cavities french flag model morphogen ontogeny recapitulation theory references citations sources embryology history embryology science science encyclopedia web nov http sciencejrankorg pages embryologyhtml germ layer encyclop dia britannica encyclop dia britannica online nov http wwwbritannicacom ebchecked topic germ layer welton john circle surrogacy circle surrogacy full service worldwide surrogate parenting agency wwwcirclesurrogacycom surrogacy reading scott f gilbert ''developmental biology'' sinauer lewis wolpert ''principles development'' oxford university press https wwwyoutubecom watchv snsp szvh click information


external links http wwwembryologych indexduhtml online course embryology http wwwindianaedu anat embryo main indexhtml indiana university 's human embryology animations http embryologymedunsweduau unsw embryology large resource information media https webarchiveorg web http wwwcambridgenetworkcouk views biolines human admixed embryo http www merriam webstercom cgi bin mwmednlmbook medical va embryo definition embryo according webster


'''evolutionary economics''' part mainstream economics well heterodox school economic thought inspired evolutionary biology much like mainstream economics stresses complex interdependencies competition growth structural change resource constraints differs approaches used analyze phenomena evolutionary economics deals study processes transform economy firms institutions industries employment production trade growth within actions diverse agents experience interactions using evolutionary methodology evolutionary economics analyzes unleashing process technological institutional innovation generating

Social science
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Evolutionary economics


testing diversity ideas discover accumulate survival value costs incurred competing alternatives evidence suggests could adaptive efficiency defines economic efficiency mainstream economic reasoning begins postulates scarcity rational agents agents modeled maximizing individual welfare rational choice agent straightforward exercise mathematical optimization renewed interest treating economic systems evolutionary systems developing field complexity economics evolutionary economics take characteristics either objects


choice decision maker fixed rather focus non equilibrium ''processes'' transform economy ''from within'' implications processes turn emerge actions diverse agents bounded rationality may learn experience interactions whose differences contribute change subject draws recently evolutionary game theory evolutionary methodology charles darwin non equilibrium economics principle circular cumulative causation naturalistic purging earlier notions economic change teleological necessarily improving human condition different


social system contrary made principle human behavior function social economic system occurred marx based theory economic development premise developing economic systems specifically course history superior economic systems would replace inferior ones inferior systems beset internal contradictions inefficiencies make impossible survive long term marx 's scheme feudalism replaced capitalism would eventually superseded socialism ref name comparingeconomicsystems ''gregory stuart'' ''comparing economic systems twenty first century'' seventh


edition south western college publishing ref approximately time charles darwin developed general framework comprehending process whereby small random variations could accumulate predominate time large scale changes resulted emergence wholly novel forms speciation followed shortly work american pragmatic philosophers peirce james dewey founding two new disciplines psychology anthropology oriented toward cataloging developing explanatory frameworks variety behavior patterns individual collective becoming increasingly obvious systematic observers


state world converged state evidence make almost inevitable development modern framework analysis substantive economic issues veblen thorstein veblen coined term evolutionary economics english began career midst period intellectual ferment young scholar came direct contact leading figures various movements shape style substance social sciences next century beyond veblen saw need taking account


cultural variation approach universal human nature could possibly invoked explain variety norms behaviors new science anthropology showed rule rather exception emphasised conflict industrial pecuniary ceremonial values veblenian dichotomy interpreted hands later writers ceremonial instrumental dichotomy hodgson veblen saw every culture materially based dependent tools skills support life process time every culture appeared stratified structure status invidious


distinctions ran entirely contrary imperatives instrumental read technological aspects group life ceremonial related past conformed supported tribal legends instrumental oriented toward technological imperative judge value ability control future consequences veblenian dichotomy specialized variant instrumental theory value due john dewey veblen make contact briefly university chicago arguably important works veblen include restricted famous works ''the theory


leisure class'' ''the theory business enterprise'' monograph ''imperial germany industrial revolution'' essay entitled ''why economics evolutionary science'' influential shaping research agenda following generations social scientists tolc tobe together constitute alternative construction neoclassical marginalist theories consumption production respectively founded dichotomy core valuational principle ceremonial patterns activity bound past one generated specific set advantages prejudices underlie


bank sweden prize economic sciences memory alfred nobel winners known sympathy field narrowly works jack downie edith penrose offer many insights thinking evolution level firm industry joseph schumpeter lived first half th century author book ''the theory economic development'' transl important note word ' 'development'' used native language german word entwicklung translated


development evolution translators day used word development french veloppement opposed evolution used darwin schumpeter later writings english professor harvard used word evolution current term common use economic development schumpeter 's book proposed idea radical time evolutionary perspective based theory assumption usual macroeconomic equilibrium something like normal mode economic affairs equilibrium perpetually destroyed entrepreneurs try introduce innovations


successful introduction innovation ie disruptive technology disturbs normal flow economic life forces already existing technologies means production lose positions within economy present state discussion one major contributions emerging field evolutionary economics publication ''an evolutionary theory economic change'' richard nelson sidney g winter authors focused mostly issue changes technology routines suggesting framework analysis change occurs constantly


economy kind evolutionary process must action proposal process darwinian nature mechanisms provide selection generate variation establish self replication must identified authors introduced term 'steady change' highlight evolutionary aspect economic processes contrast concept 'steady state' popular classical economics approach compared contrasted population ecology organizational ecology approach sociology see douma schreuder chapter recently nelson dosi pyka malerba winter scholars


proposing update state art evolutionary economics milton friedman proposed markets act major selection vehicles firms compete unsuccessful rivals fail capture appropriate market share go bankrupt exit variety competing firms products practices matched markets products practices determined routines firms use standardized patterns actions implemented constantly imitating routines firms propagate thus establish inheritance successful practices general theory process proposed kurt dopfer john foster


jason potts micro meso macro framework economic processes part life processes intrinsically evolutionary evolutionary equation describe life processes analytical formula main factors economic processes fixed cost variable cost derived economic return competitiveness economic entities different characteristics different kinds environment calculated change environment causes change competitiveness different economic entities systems process evolution economic systems recent years evolutionary models used assist


decision making applied settings find solutions problems optimal product design service portfolio diversification evolution unified growth theory role evolutionary forces process economic development course human history explored past decades oded galor omer moav advanced hypothesis evolutionary forces significant role transition world economy stagnation growth highlighting persistent effects historical prehistorical conditions evolution composition human characteristics development


process galor moav argued malthusian pressure determined size composition human population lineages whose traits complementary economic environment higher income therefore higher reproductive success inevitable propagation traits fostered growth process ultimately contributed take epoch stagnation modern era sustained growth evolution predisposition towards child quality galor moav hypothesize malthusian epoch natural selection amplified prevalence traits associated predispositions towards child quality human


population triggering human capital formation technological progress onset demographic transition emergence nbsp sustained economic growth testable predictions evolutionary theory underlying mechanisms confirmed empirically ref name ref quantitatively specifically genealogical record half million people quebec period suggests moderate fecundity hence tendency towards investment child quality beneficial long run reproductive success finding reflect adverse effect higher fecundity marital age children level education likelihood survive reproductive age ref


name evolution time preference oded galor omer ozak examine evolution time preference course human history hypothesize establish empirically agricultural characteristics favorable higher return agricultural investment malthusian era triggered process selection adaptation learning increase prevalence long term orientation among individuals society establish variations agricultural characteristics across globe associated contemporary differences economic human behavior technological adoption education saving smoking evolution loss aversion


oded galor viacheslav savitskiy explore evolutionary foundation phenomenon loss aversion theorize confirm empirically evolution loss aversion reflects evolutionary process humans gradually adapted climatic shocks asymmetric effects reproductive success period available resource close subsistence consumption particular establish individuals ethnic groups descended regions characterized greater climatic volatility tend loss neutral whereas originated regions climatic conditions spatially correlated tend


loss averse evolution risk aversion oded galor stelios michalopoulos examine coevolution entrepreneurial spirit process long run economic development specifically argue early stages development risk tolerant entrepreneurial traits generated evolutionary advantage rise prevalence trait amplified pace growth process however advanced stages development risk aversion gained evolutionary advantage contributed convergence across countries evolutionary psychology different approach apply evolutionary psychology principles economics argued explain problems


inconsistencies biases rational choice theory basic economic concept utility may better explained terms set biological preferences maximized evolutionary fitness ancestral environment necessarily current one words preferences actions decisions promise utility eg reaching piece cake formed ancestral environment adaptive advantages decisions eg maximizing calorie intake loss aversion may explained rational living subsistence level reduction resources may meant death


people differ characteristics cooperative behavior cheating becoming increasingly less successful strategy numbers cheaters increase ref name aep another argument humans poor intuitive grasp economics current environment different ancestral environment ancestral environment likely relatively little trade division labor capital goods technological change slow wealth differences much smaller possession many available resources likely zero sum games large inequalities caused various forms exploitation humans therefore may poor intuitive understanding


benefits free trade causing calls protectionism value capital goods making labor theory value appealing may intuitively undervalue benefits technological development ref name aep may tendency see number available jobs zero sum game total number jobs fixed causes people realize minimum wage laws reduce number jobs believe increased number jobs nations necessarily decreases number jobs nation large income inequality may easily viewed


institutional economics review giovanni dosi robert h frank references reading aldrich howard e geoffrey hodgson david l hull thorbj rn knudsen joel mokyr viktor j vanberg defence generalized darwinism ''journal evolutionary economics'' october pp nbsp canterbery e ray '''the theory leisure class'' theory demand' warren g samuels editor ''the founding institutional economics'' london new york routledge pp douma sytse hein schreuder economic approaches organizations th edition london pearson hodgson geoffrey ''the evolution institutional economics agency structure


darwinism american institutionalism'' london new york routledge richard r nelson sidney g winter '' https booksgooglecom booksid kx hxxrkc evolutionary theory economic change '' harvard university press shiozawa yoshinori evolutionary economics st century manifext ''evolutionary institutional economics review'' ''' ''' november pp nbsp veblen thorstein b economics evolutionary science ''quarterly journal economics'' july pp nbsp madureira den hartog f baken n holonic framework understand apply information processes evolutionary economics survey proposal netnomics doi http rdcube nqeg journals ''journal economic issues'' sponsored


association evolutionary economics http wwwafeenet ''journal evolutionary economics'' https wwwspringercom economics journal description sponsored international josef schumpeter society ''journal institutional economics'' sponsored european society evolutionary political economy https wwwspringercom economics economic theory journal ''evolutionary institutional economics review'' sponsored japan association evolutionary economics springer http wwwthenatureofvaluecom nature value invest adaptive economy book economy evolutionary system ''netnomics'' springer external links https webarchiveorg web http wwwbusinessaaudk evolution evolutionary economics et al prof esben andersen aalborg university denmark http wwwthemeistercouk economics evolutionary economicshtm evolutionary economics jp birchall http wwweconomicswebinstituteorg methodologyhtm methodology evolutionary economics v piana innovation


economics schools economic thought dichotomies thorstein veblen


'''geopolitics''' greek ''g '' earth land ''politik '' politics study effects earth 's geography human physical politics international relations ref name ref geopolitics usually refers countries relations may also focus two kinds states ' 'de facto'' independent states limited international recognition relations sub national geopolitical entities federated states make federation confederation quasi federal system level international relations geopolitics method studying foreign policy understand explain predict international political

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behavior geographical variables include area studies climate topography demography natural resources applied science region evaluated geopolitics focuses political power linked geographic space particular territorial waters land territory correlation diplomatic history topics geopolitics include relations interests international political actors focused within area space geographical element relations create geopolitical system critical geopolitics deconstructs classical geopolitical theories showing political ideological functions great powers ref name ref works discuss geopolitics renewable energy according christopher gogwilt


researchers term currently used describe broad spectrum concepts general sense used synonym international political relations specifically imply global structure relations usage builds early twentieth century term pseudoscience political geography pseudoscientific theories historical geographic determinism ref name ref ref name united states alfred thayer mahan sea power alfred thayer mahan frequent commentator world naval strategic diplomatic affairs mahan believed national greatness inextricably associated


sea particularly commercial use peace control war mahan 's theoretical framework came antoine henri jomini emphasized strategic locations choke points canals coaling stations well quantifiable levels fighting power fleet conducive control sea proposed six conditions required nation sea power advantageous geographical position serviceable coastlines abundant natural resources favorable climate extent territory population large enough defend territory society aptitude sea commercial enterprise government influence


inclination dominate sea mahan distinguished key region world eurasian context namely central zone asia lying north stretching asia minor japan zone independent countries still survived turkey persia afghanistan china japan mahan regarded countries located britain russia scylla charybdis two monsters britain russia latter mahan considered threatening fate central asia mahan impressed russia 's transcontinental size strategically favorable position


southward expansion therefore found necessary anglo saxon sea power resist russia homer lea homer lea ''the day saxon'' asserted entire anglo saxon race faced threat german teuton russian slav japanese expansionism fatal relationship russia japan germany assumed urgency natural forces coalition directed survival saxon supremacy dreadful dreibund lea believed japan moved far east russia india germans would strike england center british empire


thought anglo saxons faced certain disaster militant opponents kissinger brzezinski grand chessboard world map concepts heartland rimland applied two famous security advisors cold war period henry kissinger zbigniew brzezinski argued continue united states geopolitical focus eurasia particularly russia despite dissolution ussr end cold war continued influence geopolitics end cold war ref name writing books subject ''diplomacy'' ''the grand chessboard american primacy


geostrategic imperatives'' ref name anglo american classical geopolitical theories revived kissinger argued belief dissolution ussr hostile intentions come end traditional foreign policy considerations longer applied would argue russia regardless governs sits astride territory halford mackinder called geopolitical heartland heir one potent imperial traditions therefore united states must maintain global balance power vis vis country long history expansionism russia second geopolitical threat


thus kissinger believed country 's interests would ever served germany russia ever form partnership country would consider principal partner would raise fears condominium without america britain france cannot cope germany russia without europe america could turn island shores eurasia nicholas j spykman 's vision eurasia strongly confirmed geopolitically america island shores large landmass eurasia whose resources population far exceed united states domination


single power either eurasia 's two principal spheres europe asia remains good definition strategic danger america cold war cold war grouping would capacity outstrip america economically end militarily danger would resisted even dominant power apparently benevolent intentions ever changed america would find grossly diminished capacity effective resistance growing inability shape events main interest american leaders maintaining balance power eurasia