bluuebunny/crossref_metadata_2025 huggingface dataset:
Sposobnost vizuelnog i auditivnog pamćenja kod djece mlađeg školskog uzrasta
Authors: Bakoč Andrijana , Vuković Bojana
Published: February 2017

Uvod. Pamćenje je dio kognitivnog sistema koga čine prijem, obrada, skladištenjei prisjećanje informacija. Cilj istraživanja je utvrđivanje dinamike razvojavizuelnog i auditivnog pamćenja kod djece mlađeg školskog uzrasta, odnosizmeđu sposobnosti pamćenja i pola, kao i povezanost sposobnosti pamćenjai školskog uspjeha.Metode. Istraživanjem je obuhvaćeno 215 učenika II, III i IV razreda osnovneškole, uzrasta 7-11 godina, i to 121 (56,3%) dječak i 94 (43,7%) djevojčice. Izškolske dokumentacije su dobijeni podaci o opštem školskom uspjehu nakraju razreda, kao i uspjehu iz pojedinih nastavnih predmeta (srpski jezik,matematika, likovna kultura i muzička kultura). Za ispitivanje sposobnostipamćenja korišćen je ACADIA test razvojnih sposobnosti – subtestovi V(vizuelno pamćenje) i VIII (auditivno pamćenje).Rezultati. Rezultati pokazuju da ispitanici imaju bolja postignuća na subtestuvizuelno pamćenje u odnosu na auditivno pamćenje. U okviru sposobnostiauditivnog pamćenja je utvrđena statistički značajna razlika u odnosu nauzrast (p < 0,0001), dok u odnosu na pol nije utvrđena statistička značajnost.Korelacije sposobnosti vizuelnog pamćenja sa opštim uspjehom (r = 0,292,p = 0,01) i uspjehom na nastavnim predmetima srpski jezik (r = 0,29, p =0,01), matematika (r = 0,32, p = 0,01) i likovna kultura (r = 0,292, p = 0,01)su statistički značajne, dok je kod auditivnog pamćenja utvrđena statističkiznačajna korelacija jedino s predmetom muzička kultura (r = 0,142, p = 0,05).Zaključak. Učenici mlađeg školskog uzrasta imaju bolja postignuća u vizuelnomu odnosu na auditivno pamćenje, a sposobnost auditivnog pamćenjase statistički značajno povećava sa uzrastom. Odstupanja od uzrasnih normimogu biti posljedica neujednačenog ritma razvoja pojedinih sposobnostikoja se spontano razrješavaju tokom razvoja. Djeca kod koje su detektovanesmetnje u vizuelnom i auditivnom pamćenju treba da budu obuhvaćenadaljom kliničkom procjenom, kao i iznalaženjem odgovarajućih puteva rehabilitacijei tretmana.
Viktimizacija i neformalni osuđenički sistem u maloletničkom zatvoru
Authors: Krstajić Goran
Published: February 2017

Uvod. Neformalni osuđenički sistem u maloletničkom zatvoru sadrži podgrupenastale na osnovu različitog statusa i moći. Takva podela implicira ipodelu po različitom stepenu viktimizacije za svaku od tri statusno različitepodgrupe neformalnog osuđeničkog sistema. Definisanje unutrašnje prirodeosuđeničke interakcije kroz njihovo delovanje u određenim neformalnimgrupama od suštinske je važnosti za sveobuhvatno razumevanje ovog socijalnogfenomena, kojem nije poklonjena pažnja u onoj meri koja je neophodna.Cilj istraživanja je utvrditi da li osuđenici u statusno različitim neformalnimgrupama imaju različit stepen viktimiziranostiMetode. Uzorak obuhvata 102 osuđena lica, koja se nalaze u zatvorenom tretmanuizdržavanja kazne zatvora u Kazneno-popravnom zavodu za maloletnikeu Valjevu. Metod istraživanja je empirijski, sistematski, neeksperimentalnimetod (survey), kao i metod teorijske analize. Osnovna istraživačka tehnikaupotrebljena u procesu prikupljanja podataka je anketiranje, koje nam jeobezbedilo jednoobraznost ispitivanja i anonimnost ispitanika.Rezultati. Dobijeni rezultat viktimiziranosti za sve tri osuđeničke podgrupedokazuje da osuđenička podgrupa “vođe”, koja je statusno najjača, ima najnižiprosečan procenat viktimiziranosti od 29%. Osuđenička podgrupa “kolektivci”,koja je statusno ispod članova podgrupe “vođe”, ima srednji prosečanprocenat viktimiziranosti od 53%. Osuđenička podgrupa “marginalci”, kojaje statusno najniža ima srednji prosečan procenat viktimiziranosti od 78%.Zaključak. Na osnovu testa viktimizacije primenjenog na uzorku osuđenikau zatvorenom tretmanu, koji su pripadnici neformalnog osuđeničkog sistema,utvrđeno je da u Kazneno-popravnom zavodu za maloletnike postoje razlike ustepenu viktimiziranosti između tri osuđeničke podgrupe: podgrupa „marginalci“ima najviši stepen viktimiziranosti, „kolektivci“ srednji, a „vođe“ najniži.
Nejednakosti u korišćenju usluga doktora porodične medicine i doktora specijaliste u Republici Srpskoj
Authors: Janković Janko
Published: February 2017

Uvod. Nejednakosti u korišćenju usluga zdravstvene zaštite postoje širomsvijeta. Cilj rada je ispitivanje uticaja demografskih, socijalno-ekonomskihnejednakosti, nejednakosti u stilu života i zdravstvenom stanju na korišćenjeusluga doktora porodične medicine i specijaliste u Republici Srpskoj, Bosnai Hercegovina.Metode. Ova studija je dio Nacionalnog istraživanja zdravlja stanovništvaRepublike Srpske provedenog 2010. godine. Od 4673 osobe uzrasta 18 i višegodina identifikovane u anketiranim domaćinstvima, 4128 je intervjuisano(1906 muškaraca i 2222 žena). Multivarijantna logistička regresiona analiza jekorišćena za procjenu uticaja različitih varijabli na korišćenje usluga primarnei specijalističke zdravstvene zaštite.Rezultati. U poređenju sa muškarcima, viši procenat žena je koristio uslugedoktora porodične medicine [unakrsni odnos (UO) = 1,34; 95% intervalpovjerenja (95% IP) = 1,13–1,60], dok je suprotno kada je u pitanju korišćenjeusluga doktora specijaliste (UO = 0,62; 95% IP = 0,49–0,77). Ljudi sa nižimobrazovanjem su posjećivali doktora porodične medicine rjeđe nego visokoobrazovani. Nema značajnih socijalnih nejednakosti u korišćenju uslugadoktora porodične medicine i specijaliste u Republici Srpskoj. Osobe sahroničnim nezaraznim oboljenjima u poređenju sa onima bez ovih oboljenjasu češće koristile usluge doktora porodične medicine (UO = 3,90; 95% IP =3,22–4,73). Muškarci i žene koji procjenjuju svoje zdravlje kao dobro su koristiliusluge doktora porodične medicine i specijaliste značajno rjeđe u odnosu naone koji procjenjuju svoje zdravlje kao loše.Zaključak. Postoje značajne demografske, socijalno-ekonomske nejednakosti,kao i nejednakosti u životnom stilu i zdravstvenom stanju osoba koje koristeusluge doktora porodične medicine i specijaliste u Republici Srpskoj. Smanjivanjenejednakosti u korišćenju zdravstvenih usluga u Republici Srpskoj jeprioritet u budućnosti.
Neodgovarajuće propisivanje lijekova starijim osobama u primarnoj zdravstvenoj zaštiti
Authors: Jotanović Neda , Nežić Lana , Vučen Marko , Lakić Dušica , Mandić Danijala
Published: February 2017

Uvod. Osobe starije životne dobi su usljed postojećih komorbiditeta izloženepovećanom riziku zbog neodgovarajućeg propisivanja lijekova. Cilj rada jebio utvrditi učestalost neodgovarajućeg propisivanja lijekova, interakcija ipotencijalnog izostanka propisivanja lijekova prema kriterijumima ScreeningTool of Older Person’s potentially inappropriate prescriptions/Screening Tool to Alertdoctors to the Right Treatment (STOPP/START) i protokolu autora Mimica-Matanović,Vlahović-Palčevski (2012).Metode. Studija presjeka je provedena u tri ambulante porodične medicinei obuhvatila je 88 pacijenata, starosti ≥65 godina. U analizi je korišćenamedicinska istorija sa trenutno propisanim lijekovima uz primjenu navedenihkriterijuma.Rezultati. Ukupan broj propisanih lijekova je bio 58, 3–9 po bolesniku. PremaSTOPP kriterijumu utvrđen je 41 slučaj neodgovarajućeg propisivanja lijekova,najčešće dugodjelujućih benzodiazepina i derivata sulfonilureje, digoksinau dozi preko 125 mcg/dan i nitrata. Prema kriterijumu Mimica-Matanović iVlahović-Palčevski utvrđeno je da su 63 lijeka imala neodgovoarajući odnosbenefit/rizik kod 54 (61,3%) bolesnika. Koristeći START kriterijum utvrđen jeizostanak primjene 61 neophodog lijeka u određenoj indikaciji kod 33 (37,5%)bolesnika, i to najčešće acetil-salicilne kiseline, statina, antikoagulanata ibeta blokatora. Ustanovljene potencijalne interakcije lijekova su se odnosilena dvostruku ili trostruku antiagregacionu terapiju, digoksin i furosemid, ikombinaciju agonista i antagonista dopamina (ropinirol i haloperidol).Zaključak. Neodgovarajuće propisivanje lijekova je prisutno kod 61,3%starijih ispitivanih bolesnika i češće je od izostanka primjene neophodnoglijeka u određenoj indikaciji. Primjena odgovarajućih kriterijuma je korisnaza utvrđivanje neodgovarajućeg propisivanja i poboljšanje bezbjednostiprimjene lijekova.
Analiza rezultata javnozdravstvene kontrole kontaminanata i ostataka antibiotika u uzorcima mesa i proizvoda od mesa u Republici Srpskoj
Authors: Petković Vesna
Published: February 2017

Uvod. Kontaminanti i ostaci antibiotika u mesu i proizvodima od mesa predstavljajujavnozdravstveni problem i povezani su sa zdravstvenim rizicima.Cilj ovog rada je bio da se utvrdi učestalost kontrole prisustva metala, radionuklidai ostataka antibiotika u mesu i proizvodima od mesa, i da se ukažena potrebu praćenja svih kontaminanata predviđenih propisima.Metode. Ispitivanje je sprovedeno kao retrospektivna studija na 254 uzorkamesa i proizvoda od mesa iz spoljnotrgovinskog i unutrašnjeg prometa u RepubliciSrpskoj u periodu 2010-2012. dostavljenih u Institut za javno zdravstvoRepublike Srpske. Uzorci su podijeljeni u 4 podgrupe: svježe meso, konzervemesa, životinjske masti i ostali proizvodi od mesa. Sadržaj metala je određenmetodom atomske apsorpcione spektrofotometrije, sadržaj radionuklidametodom gama spektrometrije visoke rezolucije, a rezidue hloramfenikolametodom kompetativne enzimske imunoanalize. Utvrđivanje zdravstveneispravnosti uzoraka je izvršeno u skladu sa propisima iz oblasti bezbjednostihrane važećim u periodu istraživanja.Rezultati. Rezultati ovog istraživanja ukazuju da nisu utvrđeni zdravstvenoneispravni uzorci hrane za ispitivana obilježja - metale, radionuklide i ostatkeantibiotika. Na prisustvo arsena, kadmijuma i olova analizirano je 31,20%uzoraka, a na prisustvo 134Cs i 137Cs 29,98% uzoraka, a rezidue hloramfenikolasu analizirane kod manje od 2% uzoraka mesa i proizvoda od mesa.Analiziranjem statističke značajnosti, razlike između vrste analiziranih kontaminanatau uzorcima mesa i proizvodima od mesa i vrste kontaminanatapreporučenih propisima, uočava se da su ovi proizvodi statistički značajnočešće analizirani na prisustvo arsena, kadmijuma i olova u odnosu na drugepreporučene kontaminante (χ2 = 303,16; p < 0,001).Zaključak. Ispitivanje učestalosti kontrola prisustva različitih kontaminanatau uzorcima mesa i proizvoda od mesa pokazalo je da su ovi proizvodistatistički značajno češće analizirani na prisustvo metala arsena, kadmijuma iolova u odnosu na druge kontaminante predviđene propisima za ovu grupuproizvoda, koje je potrebno kontinuirano laboratorijski pratiti.
Naučno nepoštenje Prevare – najteži prekršaji etike nauke
Authors: Bogdanović Gordana , Vučković Dekić Ljiljana
Published: February 2017

Osnovni postulat nauke je istinito, objektivno i potpuno prikazivanje rezultataistraživanja – naučno poštenje. Etički kodeks naučno-istraživačkog rada zvanidobra naučna praksa (DNP) naglašava da je pošten pristup istraživačkomprocesu u svim njegovim fazama, kao i pošten odnos prema svim učesnicima uistraživanju – prema sebi, saradnicima i konkurentima – osnovni etički principnauke, koji važi za sve naučne discipline, sve naučnike i sve nacije. Velikavećina naučnika se pridržava ovog etičkog kodeksa, ali se povremeno otkrivajunedopustive naučne prevare, od kojih su najteže fabrikovanje i falsifikovanjepodataka i plagijatorstvo (FFP trijada). Kako ovakve prevare nanose ogromnuštetu ne samo instituciji u kojoj su se desile, nego i čitavoj naučnoj zajednici,u dokumentu DNP se objašnjavaju etiopatogeneza prevara, fenomenologijai načini sprečavanja ovakvih krajnje nepoželjnih i štetnih događaja. Sa ovimetičkim kodeksom treba da se upoznaju svi članovi akademske zajednice,a pridržavanje ovih principa je obavezujuće za svakog istraživača. U ovomčlanku ukazujemo na najnovije afere otkrivene u različitim oblastima nauke,kao i na mere prevencije i sankcionisanja naučnog nepoštenja.
UTICAJ DODATNE NASTAVE FIZIČKOG VASPITANJA NA PROMJENE MORFOLOŠKIH KARAKTERISTIKA, MOTORIČKIH I FUNKCIONALNIH SPOSOBNOSTI KOD UČENIKA OSNOVNOŠKOLSKOG UZRASTA
Authors: Lucić Marko , Okuka Aleksandar
Published: February 2017

Pozitivne efekte transformacionih procesa moguće je očekivati samo pod uslovom da jeprogramiranje takvog rada prilagođeno individualnim sposobnostima i osobinama učenika.Cilj rada je utvrđivanje uticaja dodatne nastave fizičkog vaspitanja na promjene morfološkihkarakteristika, motoričkih i funkcionalnih sposobnosti. Metod je činilo prikupljanjerelevantne literature u periodu od 2005-2013 godine, te njihovo analiziranje. Rezultati jasnopokazuju korist dodatne nastave fizičkog vaspitanja. Zaključujemo da izmeđueksperimentalne i kontrolne grupe poslije primjenjenih programa ima statistički značajnihrezultata nepredka. S toga ističemo veliku korist dodatne, programirane nastave i njen značaju fizičkom vaspitanju koji svakako može da posluži kao osnova za dalji rad i poboljšanjemorfoloških karakteristika, motoričkih sposobnosti, i funkcionalnih sposobnosti učenika.
PERCEPCIJA VAŽNOSTI PREDMETA TJELESNI I ZDRAVSTVENI ODGOJ KOD UČENIKA OSNOVNIH ŠKOLA
Authors: Stanojević Dalibor
Published: February 2017

Ubrzani razvoj tehnologije danas je u mnogo čemu olakšao ljudski život ali je isto tako i rezultiraosmanjenjem tjelesne aktivnosti kod svih dobnih grupa. Dobro je poznata činjenica da tjelesnaaktivnost kod djece utiče na zdravlje i razvoj, a i prevenira razvoj rizičnih faktora u kasnijoj životnojdobi. Prema rezultatima studije švedskih naučnika tjelesni odgoj može poboljšati ocjene učenika izdrugih predmeta. Tjelesne aktivnosti kako u školi tako i izvan nje predstavljaju područje u kojem sudjeca posvećena isključivo svom tjelesnom razvoju i zdravlju. Tjelesni odgoj, kako navode Allison etal. (2000) predstavlja predmet u školskom sistemu u kojem se od učenika očekuje da stekne znanja ivještine u području sporta i tjelesne aktivnosti. Cilj tjelesnog i zdravstvenog odgoja je pomoćiučenicima da shvate, razviju i usvoje obrasce zdravog života. Nadalje, osnovni cilj fizičke aktivnosti itjelesnog vježbanje u školama je uticati na sve bazično-motoričke sposobnosti djece. Zbog toga jeveoma bitno i da sama djeca imaju pozitivnu percepciju o važnosti zdravstvenog i tjelesnog odgoja.Zbog svega navedenog cilj ovog rada je utvrditi percepcije učenika osnovnih škola prema predmetutjelesni i zdravstveni odgoj.
The Relationship Between Arch Height and Arch Flexibility
Authors: Zifchock Rebecca Avrin , Theriot Christal , Hillstrom Howard J. , Song Jinsup , Neary Michael
Published: February 2017

Background:

The correlation between arch structure and injury may be related to the fact that foot structure influences foot function. Foot structure is often defined by arch height, although arch flexibility may be just as important to form a more complete description. We propose an arch flexibility classification system, analogous to arch height classification, and then use the classification system to examine the relationship between arch flexibility and arch height.

Methods:

Arch height index was calculated in 1,124 incoming military cadets, of whom 1,056 had usable data. By measuring arch height during both sitting and standing, a measurement of arch flexibility could also be calculated. These values were used to create five arch flexibility categories: very stiff, stiff, neutral, flexible, and very flexible. The distribution of arch flexibility types among arch height categories was statistically compared.

Results:

The goodness of fit test showed a disproportionate number of each arch flexibility type in each of the arch height categories (P < .01). The largest proportion of cavus feet was very stiff and the smallest proportion was very flexible. Conversely, the largest proportion of planus feet was very flexible and the smallest proportion was very stiff.

Conclusions:

The results of this research support the common belief that cavus feet tend to be very stiff and planus feet tend to be very flexible.
A phylogenetic transform enhances analysis of compositional microbiota data
Authors: Silverman Justin D , Washburne Alex D , Mukherjee Sayan , David Lawrence A
Published: February 2017

Surveys of microbial communities (microbiota), typically measured as relative abundance of species, have illustrated the importance of these communities in human health and disease. Yet, statistical artifacts commonly plague the analysis of relative abundance data. Here, we introduce the PhILR transform, which incorporates microbial evolutionary models with the isometric log-ratio transform to allow off-the-shelf statistical tools to be safely applied to microbiota surveys. We demonstrate that analyses of community-level structure can be applied to PhILR transformed data with performance on benchmarks rivaling or surpassing standard tools. Additionally, by decomposing distance in the PhILR transformed space, we identified neighboring clades that may have adapted to distinct human body sites. Decomposing variance revealed that covariation of bacterial clades within human body sites increases with phylogenetic relatedness. Together, these findings illustrate how the PhILR transform combines statistical and phylogenetic models to overcome compositional data challenges and enable evolutionary insights relevant to microbial communities.
Towards a mechanistic foundation of evolutionary theory
Authors: Doebeli Michael , Ispolatov Yaroslav , Simon Burt
Published: February 2017

Most evolutionary thinking is based on the notion of fitness and related ideas such as fitness landscapes and evolutionary optima. Nevertheless, it is often unclear what fitness actually is, and its meaning often depends on the context. Here we argue that fitness should not be a basal ingredient in verbal or mathematical descriptions of evolution. Instead, we propose that evolutionary birth-death processes, in which individuals give birth and die at ever-changing rates, should be the basis of evolutionary theory, because such processes capture the fundamental events that generate evolutionary dynamics. In evolutionary birth-death processes, fitness is at best a derived quantity, and owing to the potential complexity of such processes, there is no guarantee that there is a simple scalar, such as fitness, that would describe long-term evolutionary outcomes. We discuss how evolutionary birth-death processes can provide useful perspectives on a number of central issues in evolution.
A cut above
Authors: He Chongsheng , Bonasio Roberto
Published: February 2017

A new technique called CUT&RUN can map the distribution of proteins on the genome with higher resolution and accuracy than existing approaches.
Meteorological anomalies lead to elevated O3 in the western U.S. in June 2015
Authors: Jaffe D. A. , Zhang L.
Published: February 2017

In winter through early summer of 2014–2015, temperatures in the western U.S. were substantially enhanced due to a persistent high‐pressure ridge and warm water in the northeastern Pacific Ocean. Concurrently, monthly averaged maximum daily 8 h average (MDA8) O3 in June 2015 was enhanced by 3–13 ppb across a large portion of the western U.S. At the Mount Bachelor Observatory (2.8 km above sea level) in central Oregon, O3 in June 2015 was enhanced by 11 ppbv compared to the long‐term mean. Some urban areas had many days in June 2015 with MDA8 values above the current air quality threshold of 70 ppbv. We show that the high O3 was associated with enhanced temperatures, reduced cloud fraction, increased stagnation, and increased biogenic emissions. The data in June 2015 show enhanced ΔO3/Δtemperature slopes at several sites, compared to previous June data, due to these multiple factors.
Radiocarbon in dissolved organic and inorganic carbon of the Arctic Ocean
Authors: Druffel E. R. M. , Griffin S. , Glynn C. S. , Benner R. , Walker B. D.
Published: February 2017

Dissolved organic carbon (DOC) in the ocean is thousands of 14C years old, yet a portion of the DOC cycles on much shorter time scales (days to decades). We present 14C measurements of DOC in the Arctic Ocean and estimate that ≥8% of the DOC in the deep Eurasian Basin contains bomb 14C. While this is a limited data set, there appears to be selective loss of modern DOC in the surface and halocline waters of the open Beaufort Sea versus the Beaufort slope. At one of the Beaufort Sea stations, there is a linear relationship between DOC Δ14C values and previously measured total hydrolysable amino acid concentrations as reported by Shen et al. (2012), indicating that deep DOC contains small amounts of bioavailable DOC. The 14C data show that not all of the deep DOC is recalcitrant.
A novel type of transient luminous event produced by terrestrial gamma‐ray flashes
Authors: Xu Wei , Celestin Sebastien , Pasko Victor P. , Marshall Robert A.
Published: February 2017

Terrestrial Gamma‐ray Flashes (TGFs), discovered in 1994 by the Compton Gamma‐Ray Observatory, are high‐energy photon bursts originating in the Earth's atmosphere in association with thunderstorms. In this paper, we demonstrate theoretically that, while TGFs pass through the atmosphere, the large quantities of energetic electrons knocked out by collisions between photons and air molecules generate excited species of neutral and ionized molecules, leading to a significant amount of optical emissions. These emissions represent a novel type of transient luminous events in the vicinity of the cloud tops. We show that this predicted phenomenon illuminates a region with a size notably larger than the TGF source and has detectable levels of brightness. Since the spectroscopic, morphological, and temporal features of this luminous event are closely related with TGFs, corresponding measurements would provide a novel perspective for investigation of TGFs, as well as lightning discharges that produce them.
Subtidal circulation in a deep‐silled fjord: Douglas Channel, British Columbia
Authors: Wan Di , Hannah Charles G. , Foreman Michael G. G. , Dosso Stan
Published: February 2017

Douglas Channel, a deep fjord on the west coast of British Columbia, Canada, is the main waterway in the fjord system that connects the town of Kitimat to Queen Charlotte Sound and Hecate Strait. A 200 m depth sill divides Douglas Channel into an outer and an inner basin. This study examines the low‐frequency (from seasonal to meteorological bands) circulation in Douglas Channel from data collected at three moorings deployed during 2013–2015. The deep flows are dominated by a yearly renewal that takes place from May/June to early September. A dense bottom layer with a thickness of 100 m that cascades through the system at the speed of 0.1–0.2 m s−1, which is consistent with gravity currents. Estuarine flow dominates the circulation above the sill depth, and the observed landward net volume flux suggests that it is necessary to include the entire complex channel network to fully understand the estuarine circulation in the system. The influence of the wind forcing on the subtidal circulation is not only at the surface, but also at middepth. The along‐channel wind dominates the surface current velocity fluctuations and the sea level response to the wind produces a velocity signal at 100–120 m in the counter‐wind direction. Overall, the circulation in the seasonal and the meteorological bands is a mix of estuarine flow, direct wind‐driven flow, and the barotropic and baroclinic responses to changes to the surface pressure gradient caused by the wind stress.
Improved TEC retrieval based on spaceborne PolSAR data
Authors: Wang Cheng , Liu Lu , Chen Liang , Feng Jian , Zhao Hai‐Sheng
Published: February 2017

It is well known that for Earth observations, the spaceborne synthetic aperture radar (SAR) systems at L‐band can be seriously affected by the ionosphere. Fortunately, the destructive ionospheric information, total electron content (TEC), can be retrieved and removed by model inversion from SAR echoes and becomes a subject of interest for ionospheric research. Considering the system noise and channel phase imbalance, this paper focuses on accurate TEC retrieval from the Faraday rotation angle, which is embedded in Advanced Land Observing Satellite phased array L‐band synthetic aperture radar (PALSAR) full‐pol data. For the consideration of denoising, averaging filtering is widely used in existing studies to remove the system noise. In order to further reduce the noise effects, a fast total variation (FTV) denoising method is applied in this paper. By using the PALSAR full‐pol data sets, a series of simulation results show that the FTV denoising is effective for noise suppression and markedly reduce the standard deviation. For the error of channel phase imbalance, a new Faraday estimator based on the covariance matrix of circular basis is proposed. Compared with previous estimators, theoretical analysis and simulation results show that this new estimator can give the best performance for sensors that are dominated by channel phase imbalance errors. Thus, the proposed estimator can be a candidate method for TEC retrieval when phase imbalance is the domain error.
A comparison of methods for estimating the geoelectric field
Authors: Weigel R. S.
Published: February 2017

The geoelectric field is the primary input used for estimation of geomagnetically induced currents (GICs) in conducting systems. We compare three methods for estimating the geoelectric field given the measured geomagnetic field at four locations in the U.S. during time intervals with average Kp in the range of 2–3 and when the measurements had few data spikes and no baseline jumps. The methods include using (1) a preexisting 1‐D conductivity model, (2) a conventional 3‐D frequency domain method, and (3) a robust and remote reference 3‐D frequency domain method. The quality of the estimates is determined using the power spectrum (in the period range 9.1 to 18,725 s) of estimation errors along with the prediction efficiency summary statistic. It is shown that with respect to these quality metrics, Method 1 produces average out‐of‐sample electric field estimation errors with a variance that can be equal to or larger than the average measured variance (due to underestimation or overestimation, respectively), and Method 3 produces reliable but slightly lower quality estimates than Method 2 for the time intervals and locations considered.
Understanding watershed hydrogeochemistry: 1. Development of RT‐Flux‐PIHM
Authors: Bao Chen , Li Li , Shi Yuning , Duffy Christopher
Published: February 2017

Model development in hydrology and geochemistry has been advancing separately with limited integration. We developed a watershed hydrogeochemical code RT‐Flux‐PIHM to understand complex interactions between hydrological processes (PIHM), land‐surface processes (FLUX—Noah Land Surface Model), and multicomponent subsurface reactive transport (RT). The RT module simulates geochemical processes including aqueous complexation, surface complexation, mineral dissolution and precipitation, and cation exchange. The RT module is verified against the widely used reactive transport code CrunchFlow. The code uses semidiscrete finite volume method and irregular gridding and offers data harvesting capabilities from national databases. The application of RT‐Flux‐PIHM is demonstrated in the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO). We aim to understand key processes that govern hydrogeochemical dynamics of the nonreactive chloride and reactive magnesium. Simulation results indicate that watershed characteristics, in particular topography, dictate the spatial distributions of water content and soil dissolution rates. Ion exchange provides buffering capacities and leads to a hysteresis loop of concentration and discharge relationship of magnesium, which differs from the open hysteresis of chloride. RT‐Flux‐PIHM offers physics‐based modeling capabilities to integrate the vast amount of water and chemistry data that have now become available, to differentiate the relative importance of competing processes, and to test hypotheses at the interface of hydrology and geochemistry.
Efficient evaluation of small failure probability in high‐dimensional groundwater contaminant transport modeling via a two‐stage Monte Carlo method
Authors: Zhang Jiangjiang , Li Weixuan , Lin Guang , Zeng Lingzao , Wu Laosheng
Published: February 2017

In decision‐making for groundwater management and contamination remediation, it is important to accurately evaluate the probability of the occurrence of a failure event. For small failure probability analysis, a large number of model evaluations are needed in the Monte Carlo (MC) simulation, which is impractical for CPU‐demanding models. One approach to alleviate the computational cost caused by the model evaluations is to construct a computationally inexpensive surrogate model instead. However, using a surrogate approximation can cause an extra error in the failure probability analysis. Moreover, constructing accurate surrogates is challenging for high‐dimensional models, i.e., models containing many uncertain input parameters. To address these issues, we propose an efficient two‐stage MC approach for small failure probability analysis in high‐dimensional groundwater contaminant transport modeling. In the first stage, a low‐dimensional representation of the original high‐dimensional model is sought with Karhunen‐Loève expansion and sliced inverse regression jointly, which allows for the easy construction of a surrogate with polynomial chaos expansion. Then a surrogate‐based MC simulation is implemented. In the second stage, the small number of samples that are close to the failure boundary are re‐evaluated with the original model, which corrects the bias introduced by the surrogate approximation. The proposed approach is tested with a numerical case study and is shown to be 100 times faster than the traditional MC approach in achieving the same level of estimation accuracy.
Analytical solution for tension‐saturated and unsaturated flow from wicking porous pipes in subsurface irrigation: The Kornev‐Philip legacies revisited
Authors: Kacimov A. R. , Obnosov Yu. V.
Published: February 2017

The Russian engineer Kornev in his 1935 book raised perspectives of subsurface “negative pressure” irrigation, which have been overlooked in modern soil science. Kornev's autoirrigation utilizes wicking of a vacuumed water from a porous pipe into a dry adjacent soil. We link Kornev's technology with a slightly modified Philip (1984)'s analytical solutions for unsaturated flow from a 2‐D cylindrical pipe in an infinite domain. Two Darcian flows are considered and connected through continuity of pressure along the pipe‐soil contact. The first fragment is a thin porous pipe wall in which water seeps at tension saturation; the hydraulic head is a harmonic function varying purely radially across the wall. The Thiem solution in this fragment gives the boundary condition for azimuthally varying suction pressure in the second fragment, ambient soil, making the exterior of the pipe. The constant head, rather than Philip's isobaricity boundary condition, along the external wall slightly modifies Philip's formulae for the Kirchhoff potential and pressure head in the soil fragment. Flow characteristics (magnitudes of the Darcian velocity, total flow rate, and flow net) are explicitly expressed through series of Macdonald's functions. For a given pipe's external diameter, wall thickness, position of the pipe above a free water datum in the supply tank, saturated conductivities of the wall and soil, and soil's sorptive number, a nonlinear equation with respect to the total discharge from the pipe is obtained and solved by a computer algebra routine. Efficiency of irrigation is evaluated by computation of the moisture content within selected zones surrounding the porous pipe.
Potential vorticity patterns in Mediterranean “hurricanes”
Authors: Miglietta M. M. , Cerrai D. , Laviola S. , Cattani E. , Levizzani V.
Published: February 2017

The potential vorticity (PV) anomalies due to the intrusion of dry stratospheric air and those generated by the tropospheric diabatic latent heating are qualitatively analyzed for five Mediterranean tropical‐like cyclones (also known as Medicanes). Model simulations show the presence of an upper level PV streamer in the early stages of the cyclone, located on the left exit of a jet stream, and a middle‐low level PV anomaly generated by the convection developing around the low‐level vortex. In the mature stage, the upper level PV anomaly around the cyclone evolves differently for each case and appears somehow dependent on the lifetime. Only for the 2006 Medicane, the PV anomalies form an intense PV tower extending continuously from the lower troposphere to the lower stratosphere.
Long‐term trends of typhoon‐induced rainfall over Taiwan: In situ evidence of poleward shift of typhoons in western North Pacific in recent decades
Authors: Liang Alice (Ting‐Yu) , Oey Leo , Huang Shiming , Chou Simon
Published: February 2017

A significant poleward shift of tropical cyclones (TCs or typhoons) and TC‐induced storm surge in the western North Pacific has occurred in recent decades. Here we use 64 year rainfall observations around Taiwan to provide an independent evidence of the shift. We show that, due to the island's unique location relative to typhoon tracks, TC‐induced rainfall trends are significantly rising west and north of the island but are insignificant east and southeast, caused by a preference in recent decades for TCs to veer more poleward. Analyses of large‐scale fields indicate that the TCs' poleward shift is caused by the weakening of the steering flow and western North Pacific subtropical high, which in turn is due to tropic‐subtropical Indo‐Pacific warming and a weakened monsoon, consistent with the expansion of the tropics due to climate change.
Exploratory Data Analysis
Authors: Hoaglin David C.
Published: February 2017

Since about 1970, “exploratory data analysis” (EDA) has most often meant the attitude, approach, and techniques developed, primarily by
John W. Tukey
, for flexible probing of data. Four main themes run through EDA: resistance, residuals, reexpression, and displays. The article describes the general approach, discusses the four themes, presents a stem‐and‐leaf display and parallel boxplots to illustrate the theme of displays, and mentions related literature.
Simulation Models, Validation of
Authors: Deaton Michael L.
Published: February 2017

Simulation models should be validated at all stages of a simulation study. Moreover, the criteria for validation are dependent on the intended uses of the model. Many statistical challenges exist for successful model validation, but a rich literature exists for addressing those challenges. The article summarizes the principles of simulation model validation, its context within a simulation study, and the issues that it should address. Sources for validation methods are provided.
Systematic Sampling
Authors: Kalton Graham
Published: February 2017

Systematic sampling is a simple and flexible way of selecting a probability sample from a finite population. It was introduced in the early days of probability sampling in survey research and it remains in widespread use today. A systematic sample is obtained by selecting a random start between 1 andkfrom a list of the population and then taking everykth element thereafter. The ordering of the list determines the precision of the survey estimates; a random order produces a sample that has the same precision as a simple random sample, whereas an order that is monotonically associated with the variables under study gives greater precision than a simple random sample. A single‐stage systematic sample is equivalent to the selection of a single cluster and, hence, variance estimation is not possible without a model assumption. Systematic sampling is widely used to select units with unequal probabilities without replacement, as, for instance, with probability proportional to size sampling in multistage surveys. In such cases, the collapsed stratum technique is frequently used for variance estimation. Systematic sampling is often applied in two dimensions in spatial surveys of geographical areas.
Processing of Survey Data
Authors: Biemer Paul P.
Published: February 2017

Upon completion of data collection, the survey data must be converted from its raw and unedited state to a verified and corrected state that is ready for analysis and/or dissemination to the users. These steps may include questionnaire inspection, data entry, editing, coding, file preparation, documentation, and data analysis. The article discusses these steps as well as their potential effect on data quality.
Interviewing Techniques
Authors: Sjoblom Micah , Schechter Susan
Published: February 2017

Interviewing techniques play an important role in the successful implementation of survey methodology and instrumentation to collect high quality data in a standardized format. Interviewers perform a variety of roles in survey administration, and the development of standardized interviewer protocols and procedures are critical to ensure the data collected meet the requirements of research objectives. Interviewers are trained on study protocols and techniques that define rules for initial outreach and study introduction with eligible participants, engagement with study participants to gain their confidence, and consistent and uniform questionnaire administration. With the introduction of Computer Assisted Interviewing over three decades ago came the need to develop techniques and strategies for interviewers to conduct interviews while manipulating computer‐based instrumentation. As the mode of administration and types of data interviewers collect have evolved over time, so have the techniques and procedures interviewers use to collect systematic, high quality observations.
Law and Environmental Statistics
Authors: Esterby Sylvia R.
Published: February 2017

Many environmental regulations and standards are based on statistical data and inferences drawn from them. Often the statistical analysis used by the US Environmental Protection Agency (EPA) or other governmental body, in developing an exposure or effluent limit or a monitoring program, is challenged by the industry or public interest group that is most affected by its decision. Then, the courts need to examine the record on which the EPA or other agency relied in setting the standard. Because there are several statutes regulating the environment in the United States and other countries, in assessing the adequacy of the underlying scientific support of a regulation or protocol, one needs to be aware of the relevant statute. This article discusses several important statistical issues that have arisen in actual cases and describes some other topics that arise in this area.
Time Series, Periodic
Authors: Lund Robert B.
Published: February 2017

This article overviews time series with periodic structures. Periodic series frequently arise in the environmental sciences. Here, extensions to covariance stationary time series are developed and used to describe series with periodic means and autocovariances. Detection of autocovariance periodicities is considered. A series of monthly averaged temperatures from Griffin, Georgia (United States), is used to illustrate the discourse.
Bayesian Methods in Project Management
Authors: Zafari Babak , Kettunen Janne
Published: February 2017

Bayesian approaches have been coupled with the conventional project management methods, such as the project evaluation and review technique, critical path method, and earned value management. The Bayesian versions of these methods rely on updating the forecast about the project's performance, measured via duration or cost at the completion, inferring from the observed data about the project's past performance. The Bayesian project management methods have been reported to provide more accurate forecast than their conventional counterparts.
Bets, Lotteries, and Gambles
Authors: Insua David R. , Arévalo Gonzalo
Published: February 2017

Bets, lotteries, and gambles correspond to key decision problem‐structuring concepts in statistical decision theory. On the basis of such concepts, the preferences and beliefs of decision makers may be assessed and used for inference, forecasting, and decision support purposes.
Surrogate Endpoints: Statistical Validation
Authors: Burzykowski Tomasz
Published: February 2017

A surrogate endpoint is intended to replace a clinical endpoint for the evaluation of new treatments when it can be measured more cheaply, more conveniently, more frequently, or earlier than the clinical endpoint. A surrogate endpoint is expected to predict the clinical benefit, harm, or lack of these. We review the statistical approaches that have been proposed to evaluate the validity of a candidate surrogate endpoint. In particular, we consider the approaches developed for the single and multiple trial settings, describe the concepts of the “individual‐level” and “trial‐level” validity of a surrogate, and discuss suitable measures of validity. We also briefly review the methods developed using the causal inference framework.
Clustering Categorical Data
Authors: Andreopoulos Bill
Published: February 2017

A growing number of clustering algorithms for categorical data have been proposed. This article describes the goals of clustering categorical data, such as scalability, robustness, and insensitivity to object ordering and minimal user‐specified parameters. We describe the main similarity metrics for categorical data, including Hamming distance and probabilistic metrics. We compare the different approaches to categorical data clustering, such as partition‐based, hierarchical, density‐based, and model‐based methods. We give examples of algorithms in each category and we explain what types of clustering goals each algorithm satisfies. We explain locality‐sensitive hashing as a fast similarity retrieval method for very large categorical datasets. We describe challenges for future work.
Frequentist Probability
Authors: Spanos Aris
Published: February 2017

The primary objective of this article is to discuss a model‐based frequentist interpretation that identifies the probability of an event with thelimitof its relative frequency of occurrence. What differentiates the proposed interpretation from the traditional ones are several key features: (i) events and probabilities are defined in the context of a statistical model , (ii) it is anchored on the strong law of large numbers, (iii) it is justified on empirical grounds by validating the model assumptions vis‐à‐vis data , (iv) the “long‐run” metaphor can be rendered operational by simple simulation based on , and (v) the link between probability and real‐world phenomena is provided by viewing data as a “truly typical” realization of the stochastic mechanism defined by . This link constitutes a feature shared with the Kolmogorov complexity algorithmic perspective on probability, which provides a further justification for the proposed frequentist interpretation.
Conditional
M
onte
C
arlo Methods
Authors: Johnson Victoria Plamadeala
Published: February 2017

This is a brief introduction to Monte Carlo estimation with focus on a variance reduction technique called the conditional Monte Carlo. A motivating example is supplied with accompanying R code.
The Digital Patient: An Emerging Platform for Health Analytics
Authors: Combs Charles Donald , Combs William Cole
Published: February 2017

Dramatic growth in data about the human body and the human in social context combined with the progress in data analytics and modeling and simulation provide an opportunity to realize a 30‐year‐old vision for a virtual human. This virtual human, as manifested by the Digital Patient for purposes of this article, will be capable of serving as a platform for improved research, education, patient care, and drug and device testing. It will also be capable of accurately representing individuals and populations over time for purposes of screening, prevention, treatment, and analysis. The more accurate descriptor is to think in terms of a Digital Patient platform with infinite combinatorial possibilities. This article provides an overview of the major research initiatives that are underway, and the challenges that must be addressed, particularly in the aggregation of data into usable formats and models. It is based on the book,
The Digital Patient: Advancing Healthcare, Research and Education
.
Quasi‐passivity‐based adaptive stabilization for switched nonlinearly parameterized systems
Authors: Pang Hongbo , Zhao Jun
Published: February 2017

This paper investigates the adaptive quasi‐passification‐based stabilization problem for a class of switched nonlinearly parameterized systems via average dwell time method. First, when all the subsystems have any same relative degree, the global practical stability is achieved by combining the recursive feedback quasi‐passification design technique with a switched adaptive control technique. The states and parameter estimation errors converge to the ball whose sizes can be reduced by choosing appropriate design parameters. Second, when the system states are unavailable for measurements, adaptive output feedback controllers are designed to stabilize the system using quasi‐passivity. The proposed output feedback controllers do not depend on any state observer. Finally, three examples show the effectiveness of the proposed methods.
Macrophages Influence Vessel Formation in 3D Bioactive Hydrogels
Authors: Moore Erika M. , Ying Grace , West Jennifer L.
Published: February 2017

Macrophages may play a beneficial role in blood vessel development. To study the role of macrophages in vessel development for regenerative medicine, a bioactive poly(ethylene glycol)‐based hydrogel scaffold that is modified for integrin‐mediated cell adhesion and biodegradation by matrix‐metalloproteinases 2 and 9 is utilized. This scaffold serves as a tunable cell microenvironment and supports the formation of microvascular networks. When encapsulated with endothelial cells, macrophages enhance vessel tubule volume within the hydrogel by nearly twofold compared to endothelial cells alone in hydrogels. Additionally, macrophages in the hydrogel alter their morphology in an endothelial cell‐dependent manner. Macrophages alone maintain high circularity with only 1% of the population demonstrating circularity ≤0.5 (indicating cell spreading), but when co‐encapsulated with endothelial cells, 46% of macrophages have a circularity ≤0.5. Macrophages 0–5 µm away from an endothelial cell have a circularity of 0.48 ± 0.22 whereas macrophages >20 µm away have a circularity of 0.83 ± 0.07. Two types of macrophage–endothelial cell interactions are seen: macrophages behaving as pericyte‐like cells and macrophages bridging between endothelial cells. Macrophages may be a novel cell target for regenerative medicine efforts where vasculature is often vital to success.
Interpenetrating Conducting Hydrogel Materials for Neural Interfacing Electrodes
Authors: Goding Josef , Gilmour Aaron , Martens Penny , Poole‐Warren Laura , Green Rylie
Published: February 2017

Conducting hydrogels (CHs) are an emerging technology in the field of medical electrodes and brain–machine interfaces. The greatest challenge to the fabrication of CH electrodes is the hybridization of dissimilar polymers (conductive polymer and hydrogel) to ensure the formation of interpenetrating polymer networks (IPN) required to achieve both soft and electroactive materials. A new hydrogel system is developed that enables tailored placement of covalently immobilized dopant groups within the hydrogel matrix. The role of immobilized dopant in the formation of CH is investigated through covalent linking of sulfonate doping groups to poly(vinyl alcohol) (PVA) macromers. These groups control the electrochemical growth of the conducting polymer poly(3,4‐ethylenedioxythiophene) (PEDOT) and subsequent material properties. The effect of dopant density and interdopant spacing on the physical, electrochemical, and mechanical properties of the resultant CHs is examined. Cytocompatible PVA hydrogels with PEDOT penetration throughout the depth of the electrode are produced. Interdopant spacing is found to be the key factor in the formation of IPNs, with smaller interdopant spacing producing CH electrodes with greater charge storage capacity and lower impedance due to increased PEDOT growth throughout the network. This approach facilitates tailorable, high‐performance CH electrodes for next generation, low impedance neuroprosthetic devices.