bluuebunny/crossref_metadata_2025 huggingface dataset:
BODY COMPONENT COMPOSITION AND STRESS-INDUCED FEATURES OF LEPTIN SECRETION IN FEMALES WITH VARIOUS BODY MASS INDEX
Authors: Smelysheva L , Musikhina E , Artenyan N , Kovaleva G , Kuznetsov G
Published: September 2020

Aim. The article aims to study the dynamics of the adipose tissue hormone leptin in healthy females with different body component composition and body mass index to assess their energy status under stress. Materials and methods. Based on anthropometry and bioimpedancemetry, three groups of girls were formed: the first group included girls with a BMI of less than 18.5 kg/m2, body mass deficiency (BMD), the second – from 18.5 to 24.9 kg/m2, normal body mass (NBM), the third – with a BMI of more than 24.9 kg/m2, which corresponds to overweight (OvBM). The body component composition was determined by bioimpedancemetry. Plasma leptin concentration was evaluated by enzyme-linked immunosorbent assay both in normal conditions and during emotional stress. Results. In the selected subgroups, a significant difference in the body component composition was found with an increase in the series of BMD → NBM → OvBM. When assessing the level of metabolic processes by the magnitude of the phase angle, it was found that 3.41% of females with BMD showed signs of increased protein catabolism. The stress-induced dynamics of the hormone leptin was evaluated. In normal conditions, the concentration of leptin in blood plasma positively correlated with BMI and depended on the component composition of the body. Conclusion. In persons with BMD, the adipose tissue hormone leptin had a negative dynamics under stress conditions, which was an adequate adaptive physiological response to stress. Females with BMD had a significantly high positive dynamics of leptin, while girls with OvBM did not have significant changes in its concentrations, which can be explained by the development of leptin resistance.
RADIO-ULNAR PRONATION VS FOREARM EXTENSION: WHICH THE BEST TO REACH THE MAXIMAL BADMINTON RACKET VELOCITY?
Authors: Phomsoupha M , Jeuvrey J , Laffaye G
Published: September 2020

Aim. Forearm extension and radio-ulnar pronation are two common components of the final movement during each badminton smash stroke. By coordinating the forearm to produce both extension and pronation at the same time, racket head velocity can be increased. Thus, this study examined maximal velocity and racket deflection during both movements in regard with skill level. Materials and methods. Twenty-two players (8 experts and 14 novices) participated in this study. Wrist, handle and racket head velocity were recorded using high speed cameras (Vicon V8i at a frequency of 250 Hz). Results. The racket head velocity with radio-ulnar pronation was 16 % higher than with forearm extension. This higher velocity resulted from an 8 % higher acceleration and a 70 % higher maximal angular velocity of the end points of the forearm segments during radio-ulnar pronation. In each movement, experts’ maximal velocity was higher than that of novices (p < .001).The maximal velocity of the racket for novices was obtained with elbow extension (20.9 ± 4.8 m/s), with a gain of 47 %, whereas for experts, it was obtained with radio-ulnar pronation (33.9 ± 5.8 m/s), with a gain of 53 %. Conclusion. The difference between the best velocities in both samples is 39 %, obtained respectively by radio-ulnar pronation for experts and an elbow extension for novices. Forearm extension and radio-ulnar pronation acceleration on the handle led to an increase in racket head velocity.
EVALUATION OF A SPORTS-SPECIFIC APPROACH IN PHYSICAL EDUCATION OF SECONDARY SCHOOL STUDENTS WITH HEALTH-RELATED ISSUES
Authors: Parfenova L , Glazkova G , Gerasimov E
Published: September 2020

Aim. The article deals with the evaluation of experimental methods in the physical education of students with different nosologies based on a sports-specific approach. Materials and methods. The study involved 90 secondary school students (grades 5–6) with health-related issues. In the experimental group (EG, n = 45), training sessions were conducted according to the deve­loped program that included volleyball and Russian lapta elements. In the control group (CG, n = 45), students were engaged in traditional activities for students of the special medical group (SMG). During the experiment, physical development, functional status, adaptive abilities, physical fitness, and physical education competencies were evaluated. Results. At the end of the experiment, the students of the experimental group showed a significant increase in the functional capacity of the body. The Shapovalova Index in EG improved by 8.90–21.70%, in CG – by 0.20–7.80%; the Ruffier Index in EG improved by 21.30–29.10%, in CG – by up to 7.80%. Moreover, students in EG had a more significant development of strength and coordination abi­lities than in CG. Conclusion. The experimental technique in physical education of secondary school students contributed to the development of physical abilities, health, and physical education competencies in participants.
HUBUNGAN POLA MAKAN DENGAN TERJADINYA GASTROESOPHAGEAL REFLUX DISEASE (GERD)
Authors: Ajjah Bunga Fauza Fitri , Mamfaluti Teuku , Putra Teuku Romi Imansyah
Published: September 2020

Latar Belakang : Gastroesophageal Reflux Disease (GERD) merupakan penyakit kronik yang terjadi pada masyarakat dewasa terutama mahasiswa. Faktor yang dapat menyebabkan GERD adalah pola makan termasuk jenis-jenis makanan tertentu yang dikonsumsi, frekuensi makan, dan ketidakteraturan makan. Mahasiswa kedokteran selalu berada di bawah tekanan akademik sehingga muncul ketidaknyamanan pencernaan yang memberi dampak bagi kualitas hidup dan aktivitas sehari-hari. Tujuan : Mengetahui hubungan pola makan dengan terjadinya Gastroesophageal Reflux Disease (GERD) pada mahasiswa Program Studi Pendidikan Dokter Fakultas Kedokteran Universitas Syiah Kuala. Metode : Penelitian ini merupakan penelitian deskriptif analitik observasional dengan desain cross sectional. Teknik pengambilan sampel yang digunakan adalah stratified random sampling sebanyak 216 subjek yang memenuhi kriteria inklusi. Pengumpulan data diperoleh dari hasil pengisian kuesioner oleh subjek menggunakan kuesioner pola makan yang sudah divalidasi dan dimodifikasi oleh peneliti dan menggunakan Gastroesophageal Reflux Disease Questionnaire (GERDQ) dalam bahasa Indonesia yang telah valid. Kuesioner pola makan dinilai dari segi keteraturan makan, frekuensi makan, jenis-jenis makanan, dan porsi makanan yang dikonsumsi. Hasil : Subjek yang memiliki pola makan buruk dan mengalami GERD sebanyak 34,2% sedangkan subjek yang memiliki pola makan baik dan tidak mengalami GERD sebanyak 86,5%. Analisis data dilakukan dengan menggunakan uji Chi Square. Hasil analisis data menunjukkan terdapat hubungan antara pola makan dengan terjadinya Gastroesophageal Reflux Disease (GERD) (p = 0,004).Simpulan : Terdapat hubungan antara pola makan dengan terjadinya Gastroesophageal Reflux Disease (GERD) pada mahasiswa Program Studi Pendidikan Dokter Fakultas Kedokteran Universitas Syiah Kuala.
Příklady dobré praxe v pedagogice
Authors: Mareš Jiří
Published: September 2020

Studie v úvodu konstatuje, že pokud má společnost zájem na zlepšování průběhu i výsledků školní edukace, mají učitelé i badatelé v pedagogice k dispozici v principu čtyři cesty. Buď postupovat „shora dolů“ (badatelé se snaží zprostředkovat výsledky svého výzkumu učitelům v praxi), nebo „zdola nahoru“ (badatelé shromažďují příklady dobré praxe, vědecky je ověřují a snaží se z nich vyvodit obecněji platné závěry). Třetí směr kombinuje oba předchozí přístupy. Čtvrtý směr můžeme stručně nazvat „dole-dole“. Jde o dobrou praxi, která se jednomu učiteli osvědčila; promyslel si ji, opakovaně ověřil a snaží se ji zpřístupnit dalším učitelům. Samotná přehledová studie má šest částí. První část hledá odpověď na tři otázky: Jak se v pedagogice definují pojmy „dobrá praxe“ a „nejlepší praxe“? Které složky jsou pro tyto pojmy klíčové? Které další pojmy se ještě užívají a čím se liší? Za referenční termín byla v této studii zvolena „dobrá praxe“.Druhá část studie uvádí ilustrativní příklady dobré praxe. Třetí část studie podává přehled výzkumných metod pro hodnocení efektivity postupů, z nichž se skládá dobrá edukační praxe. Čtvrtá část studie shrnuje způsoby, jimiž lze informovat odbornou veřejnost o příkladech dobré praxe. Pátá část studie se věnuje tomu nejdůležitějšímu: zda je možno přenášet příklady dobré praxe do jiných podmínek (k jiným učitelům, do jiných škol, do jiných zemí) a tak zlepšovat výuku ve školách. Šestá část diskutuje problémy, které využívání příkladů dobré praxe s sebou přináší, a varuje před zjednodušováním praktických aplikací. Naopak korektní a tvořivé využívání příkladů dobré praxe obohacuje fungování školy a její výchovněvzdělávací výsledky. Navíc výzkum prováděný učiteli-praktiky ve školách pomáhá profesionálnímu rozvoji učitelů a též přináší nové podněty pro vědecký pedagogický výzkum. Klíčová slova: školní edukace; učitelé; výzkumníci; vyučování; dobrá edukační praxe; nejlepší edukační praxe; sdílení dobré praxe; přenos dobré praxe; efektivita dobré praxe.
Využití metody Delphi pro identifikaci klíčových témat vzdělávací politiky
Authors: Pazour Michal , Straková Jana
Published: September 2020

Cílem příspěvku je popsat postup, výsledky a zkušenosti aplikace metody Delphi v projektu „Identifikace prioritních témat ve vzdělávání“, který byl realizován na jaře roku 2019. Metoda Delphi se zpravidla využívá k vytváření konsenzu mezi experty, k analýze a lepšímu porozumění určité oblasti či ke generování návrhů opatření souvisejících s realizací konkrétních veřejných nebo firemních politik. V tomto konkrétním případě byla využita jako nástroj pro získání hlubšího vhledu do postojů a názorů vzdělávací komunity na nedostatky současného vzdělávacího systému v ČR.Metody. Šetření metodou Delphi probíhalo elektronicky ve dvou kolech, v nichž bylo hodnoceno 39 výroků o nedostatcích systému vzdělávání z pohledu míry souhlasu či nesouhlasu a z hlediska významnosti pro pozitivní změnu ve vzdělávání. Šetření se zúčastnilo celkem 275 respondentů v prvním kole a 151 ve druhém kole. Tito respondenti reprezentovali velmi rozmanité spektrum aktérů systému vzdělávání v ČR.Výsledkem šetření byl soubor námětů na témata a problematické oblasti, kterými by se měla zabývat současná a budoucí vzdělávací politika v ČR. Významným výstupem šetření je také soubor více než 10 000 komentářů k jednotlivým hodnoceným výrokům, které vysvětlují postoje respondentů k posuzovaným tématům.Závěry. Šetření potvrdilo a kvantitativně doložilo hlavní závěry o nedostatcích v systému vzdělávání v ČR, které jsou v odborné komunitě dlouhodobě diskutovány. Současně přineslo širokou informační bázi o postojích ve vzdělávací komunitě. Z metodického hlediska jsou získané zkušenosti bezesporu příspěvkem do diskuse o přínosech a limitech metody Delphi uplatněné pro získání vhledu do postojů odborné komunity při formulaci veřejných politik.
Cesta ke čtenářské gramotnosti: Znalost konvencí tištěného textu u dětí předškolního věku
Authors: Gavora Peter
Published: September 2020

Abstrakt: Čtení nespočívá pouze v identifikaci písmen a chápaní jejich spojení ve slovech. Čtenář také musí znát grafické a formální vlastnosti knihy, směr čtení a další prvky, které se souborně nazývají konvence tištěného textu. K jejich osvojení dochází již v předškolním věku.Cíle. Cílem výzkumu bylo zjistit, jaká je úroveň znalosti konvencí tištěného textu u souboru českých dětí v předškolním věku (n = 142) a kterými faktory je tato úroveň podmíněna. Výzkumným nástrojem byl test vyvinutý M. M. Clayovou, který zjišťoval znalost 19 prvků tištěného textu. Druhým výzkumným nástrojem byl dotazník, v němž rodiče dětí popisovali gramotnostní prostředí domova.Výsledky. Podle očekávání výkon dětí v testu stoupal s věkem a zároveň se s věkem také zmenšovaly rozdíly mezi dětmi. Děti dosahovaly nejlepších výsledků v položkách, jež se týkaly chápání textu jako nositele příběhu, obálky knihy, identifikace velkého písmena a směru čtení.Regresní analýza zkoumala čtyři modely, které predikovaly výkon dětí v testu znalosti konvencí tištěného textu. Nejlepšími prediktory byly věk dětí, trvání čtení dítěti rodiči, alfabetické aktivity rodiče s dítětem a počet knih, které mělo dítě k dispozici. Zatímco první prediktor představuje zrání dítěte a kumulativní zkušenost s knihou v průběhu let, další tři prediktory charakterizují gramotnostní prostředí rodiny. Tyto čtyři prediktory objasnily 29,4 % celkové variance modelu. Oproti očekávání měla frekvence čtení dítěti slabý vztah ke znalostem konvencí textu.Závěry. Znalost konvencí textu se ukazuje nejen jako zajímavý teoretický rámec, ale i jako cenná diagnostická proměnná, která vypovídá nejen o důležitém prvku čtenářské pregramotnosti, ale také o gramotnostním prostředí rodiny.
Když potenciálně rozvíjející situace nerozvíjí: kritické didaktické incidenty v problémově orientované výuce
Authors: Češková Tereza
Published: September 2020

Ukazuje se, že pro učitele jsou kompetence stále nesrozumitelné a ve výuce obtížně uchopitelné a že jejich rozvíjení u žáků je tím potenciálně omezeno. Tato studie se zaměřuje na kompetenci k řešení problémů, konkrétně pak na situace, které mají potenciál tuto kompetenci u žáků rozvíjet (tj. na problémově orientované situace, v jejichž jádru stojí problémově orientované úlohy). To, že učitel ve výuce využije problémově orientované učební úlohy, automaticky neznamená, že tím u žáků kompetenci k řešení problémů rozvíjí.Cílem článku je proto popsat, co způsobuje, že přestože výuka obsahuje úlohy nesoucí potenciál danou kompetenci rozvíjet, tento potenciál není využit.Metody. Zkoumáno je 19 výukových situací identifi kovaných v 10 vyučovacích hodinách přírodovědy, které stavěly na problémově orientovaných úlohách, avšak zároveň nebyly hodnoceny jako rozvíjející. Pomocí mikroanalytického přístupu metodou analýzy kritických didaktických incidentů jsou ukázány konkrétní podoby průběhu problémově orientovaných situací ve výuce s cílem pojmenovat opakující se jevy, kvůli nimž jejich potenciál není využit.Výsledky. Dominantní skupinou incidentů bylo přílišné vztahování aktivity na učitele, které se projevovalo tím, že učitel natolik žáky provázel řešením úlohy, že ji de facto řešil sám. Ve studii jsou podrobně ukázány mechanismy, jak a za jakých okolností k tomuto a dalším incidentùm docházelo. Pojmenování některých jevů, které oslabují rozvíjení klíčových kompetencí ve výuce, může pomoci ukázat, čeho se v praxi vyvarovat.
Enlightenment faith in human creative capacities
Authors: Drozdowicz Zbigniew
Published: September 2020

In this article I present an argument for the thesis that one of the most significant revaluations of the Enlightenment was the creation and popularization of faith in the effective shaping of fate by man himself. In every example the Enlightenment had been referring to the creative possibilities of human reason. However, major differences occurred in understanding this very reason and its application in the praxis between the main representatives of the period. In my remarks I recall just a few of selected representatives of the English, Scottish and French enlightenment philosophy. The broadening of that list with other names, including the representatives of other nations, would allow probably to present much more diversified variants of this Enlightenment faith which since that period is a specific distinguishing mark of modernity.
The Evangelical Christians-Baptists: between the religious tradition of Russia and foreign influence
Authors: Pełczyński Grzegorz
Published: September 2020

Evangelical Christians and Baptists are Evangelical denominations representing Protestant beliefs in Russia. They share a similar approach to doctrinal matters and at one point in history united into a single ecclesiastical organisation. Domestic factors, in particular, as well as foreign influences played an important role in the Russian origins of Evangelical groups, which contributed to the Evangelical movement’s religious inquisitiveness, spiritual fervour, and readiness for martyrdom around the world. In order to develop a thorough understanding of Evangelical Christians and Baptists in Russia, one needs to explore their political and cultural backgrounds.
Hijab – muslim response to globalisation?
Authors: Kuriata Agnieszka
Published: September 2020

Young Muslim women are coming under an increasing influence of globalisation processes and follow global trends, which also includes fashion. This entails a certain balancing act between being modern and being religious. The author of the present paper attempts to address the question whether the hijab may be considered a Muslim answer to globalisation through its presence within the so-called “hijab fashion,” or that perhaps, to the contrary, it constitutes a symbol of a growing isolation and separation of Muslim minorities inhabiting the countries of western Europe.
The effect of multi-stage modification on the performance of Savonius water turbines under the horizontal axis condition
Authors: Mahesa Prabowoputra Dandun , Hadi Syamsul , Sohn Jung Min , Prabowo Aditya Rio
Published: September 2020

Indonesia has the abundant potential of hydropower but not yet processed optimally, which intensely depends on fossil fuel. Hydropower installed in Indonesia is only 11,272 MW, from the estimated potential approximately 94,476 MW. This data shows that 89% of the hydropower potential in Indonesia has not been processed. One of the present efforts to utilize this resource is addressed to develop the Savonius water turbine. Conventional water Savonius turbines have a comprehensible structure and easy to be applied. However, the turbines produce relatively small power, which requires further assessment to improve its performance. The current study is performed by considering geometric changes on the water Savonius turbine to observe their effect on power characteristics. Considered changes are made on the number of stages, and the angle between stages, specifically a single-stage, two-stage 0°, Two-stage 90°, three-stage 0°, and three Stage 120°. The research was carried out by designing simulation model using ANSYS software with CFX Solver. Water speed is determined to 0.8 m/s, while plates with 110 mm in diameter and 110 mm in height are incorporated as rotor configuration. Based on this study, it can be concluded that the addition of the stage affected improving the performance of the Savonius water turbine, where the multi-stage turbine experienced an increment compared to conventional water turbines. The interesting tendency was found on the two-stage rotors with angle of 0° which produced a smaller Cpmax compared to the conventional water Savonius turbines.
»Kein Patent auf Leben«!?
Authors: Gantner Gösta , Klein Wolfgang-Michael
Published: September 2020

In den vergangenen drei Jahrzehnten hat sich die Bedeutung von Patenten in den Lebenswissenschaften grundlegend verändert. Analog zum rasanten Anstieg von Biopatentanmeldungen und deren ökonomischer Relevanz formierte sich der Protest gegen sog. „Patente auf Leben“. Ethische Argumente gewannen zunehmend Einfluss in den Debatten zwischen Gegner*innen und Befürworter*innen eines umfangreichen Patentschutzes biotechnologischer Innovationen und beförderten den gesellschaftlichen Diskurs um die Legitimität von Biopatenten. Am Beispiel dieser Kontroverse wird die Professionalisierung zivilgesellschaftlicher Initiativen und Akteure als zentrales Erfolgskriterium dargestellt. Hierdurch konnten politische Parteien, Vertreter*innen aus Medien und Behörden und letztlich eine breitere Öffentlichkeit für die Argumente der Kritiker*innen sensibilisiert werden. Damit wurde das Patentrecht auch politisch relevant. An dieser Ethisierung und Politisierung waren Greenpeace und viele weitere Gruppierungen maßgeblich beteiligt.
Stable numerical methods for determination of the molecular clusters force fields
Authors: Kuramshina Gulnara M. , Zakharov Alexander A.
Published: September 2020

The inverse problem of molecular force fields calculation is considered within the theory of regularization.
In our strategy, we choose the stabilizing matrix

F
0

F^{0}

as a result of quantum mechanical calculations.
The solution of the inverse problem is finding a matrix 𝐹 which is the nearest by the chosen Euclidean norm to the given ab initio

F
0

F^{0}

.
The optimized solution is referred to as regularized quantum mechanical force field (RQMFF).
Regularizing algorithms of molecular force fields calculation based on the joint treatment of experimental and ab initio quantum mechanical data have been applied to the calculations of molecular force fields (matrices of force constants) for small water clusters (H2O)𝑛 (

n
=

2
,
3

n=2,3

).
Impact of parental origin of X-chromosome on clinical and biochemical profile in Turner syndrome
Authors: Malhotra Rakhi , Shukla Rashmi , Kabra Madhulika , Gupta Yashdeep , Jyotsna Viveka P. , Khadgawat Rajesh
Published: September 2020

Objectives

To evaluate if the parental origin of X-chromosome has an impact on the phenotype and biochemical profile in Turner syndrome (TS). Result of the previous studies have been equivocal and could be attributable to the multicentric study design with different experts examining heterogeneous TS population of various ethnic background.

Methods

A cross-sectional single center study from Northern India. Fifty nine diagnosed subjects of TS and their parents participated in the study. Parental origin of intact X-chromosome was determined using 12 highly polymorphic short tandem repeats (STR) on X-chromosome. For the evaluation of parent-of-origin effects, typical phenotypic traits including congenital malformations, anthropometry, body composition by dual energy X-ray absorptiometry (DXA) and biochemical profile were compared. Clinical stigmata of TS in all subjects were examined by a single expert.

Results

The intact X-chromosome was of maternal origin (Xm) in 49.1% subjects while 50.9% had paternal origin (Xp). Skeletal anomalies were more common in Xm group, out of which prevalence of short neck and short fourth metatarsal reached statistical significance (p=0.04 and 0.01 respectively). A strong correlation was observed between subject’s baseline height standard deviation score (Ht SDS) and paternal height (r=0.593, p<0.001), maternal height (r=0.564, p<0.001) and mid-parental height (MPH) (r=0.372, p=0.047) in Xp group. This effect was not seen in Xm subjects whose baseline Ht SDS showed no significant correlation with maternal height, paternal height or MPH. No differences were detected between the groups with regard to biochemical profile or body composition.

Conclusions

We speculate that the differences in skeletal anomalies and height correlations between Xm and Xp groups could be due to the modifying effect of epigenetic signature on short stature homeobox (SHOX) gene of Xm. SHOX gene is not modified on Xp thereby explaining the paucity of skeletal changes and height correlations in Xp subjects.
Timing and regimen of puberty induction in children with hypogonadism: a survey on the practice in Arab countries
Authors: Hamza Rasha Tarif , Deeb Asma , Al Saffar Hussain , Alani Sarah Hussein , Habeb Abdelhadi
Published: September 2020

Objectives

There are some variations in the practice of puberty induction between different regions; however, data from Arab countries are lacking. We aimed to survey the practice of pediatric endocrinologists in Arab countries on the timing and regimen for puberty induction in girls and boys with hypogonadism.

Methods

An online questionnaire was emailed to physicians registered in the Arab Society for Paediatric Endocrinology and Diabetes.

Results

In total, 106 replies from 17 countries were received. In non Turner syndrome (TS) girls, puberty was induced by 49.4% of participants at 12–13 years and by 32.5% at  ≥14 years. Ethinyl estradiol and conjugated estrogen were the most popular preparations used (29.7 and 16.6%, respectively). Of the participants, 60% introduce progesterone either at 2–3 years after starting estrogen or following a significant breakthrough bleeding on estrogen. In girls with TS, 84.2% of participants prescribed estrogen to those aged 11 years and older (51.5% at 11–12 years) and 5.3% prescribed it to those at the prepubertal age. In boys, 57.3% of participants induce at ≥14 years, 80.6% use intramuscular testosterone and 46.5% start with 50 mg/kg/month. Human chorionic gonadotropin is more used in non-Gulf Arab countries (18.2 vs. 2.9%; p 0.036) with a trend of using oral testosterone undecanoate in Gulf states (12.2 vs. 2.0%; p 0.051).

Conclusions

We describe the approach to puberty induction in boys and girls among pediatric endocrinologists in Arab countries. The observed variation in practice would be useful in developing regional consensus guidelines on puberty induction in children with hypogonadism.
Occurrence of arbuscular mycorrhizal fungi spores in soils of some legumes and their response to varying concentrations of phosphorus application
Authors: Alori Elizabeth Temitope , Fawole Oluyemisi Bolajoko , Akanji Medinat Olaitan
Published: September 2020

A potted experiment arranged in a 5 × 3 factorial in a randomized complete block design was undertaken to investigate the occurrence of arbuscular mycorrhizal fungi (AMF) in the soil of five leguminous plants: Cajanus cajan (L.) Huth, Centrosema pascuorum Martius ex Benth, Crotalaria ochroleuca G. Don, Lablab purpureus (L.) Sweet and Mucuna pruriens (L.) DC. The effects of varying phosphorus concentrations (P0) (0 kg/ha of single superphosphate), P1 (100 kg/ha of single superphosphate) and P2 (200 kg/ha of single superphosphate) on the population of AMF spores under these legumes were also carried out. The AMF spores in soil samples were extracted at 19 weeks after planting, using the wet sieving and decanting method, and enumerated with the aid of a stereoscopic microscope. Spores of different species of genera Glomus and Gigaspora were encountered in the soils of the five leguminous plants. Spores of Glomus species predominated while the spores of Gigaspora species were found in lower numbers. The total AMF population was significantly affected by legume species (p ≤ 0.05). The total AMF spore counts were higher in the soils of Mucuna pruriens and Crotolaria ochroleuca (p ≤ 0.05). The populations of Glomus mossae in soils decreased with increasing level of applied phosphorus (p ≤ 0.05). A positive correlation was recorded between the total AMF spores, the predominant AMF spores and soil pH, while the organic matter content and the available phosphorus were negatively correlated with both the total AM spores and the predominant AMF spores.
Interleukin-27 levels in patients with myasthenia gravis
Authors: Liu Xiao-Jiao , Zhang Lin-Jie , Yi Ming , Li Li-Min , Wang Jing , Qi Yuan , Zhao Peng , Zhang Da-Qi , Yang Li
Published: September 2020

Interleukin-27 (IL-27), which belongs to IL-12 family, influences the function of T cells (Tregs) through regulating the expression, and function of forkhead box P3 (FoxP3). In this study, we detected the IL-27 serum levels in 59 myasthenia gravis (MG) patients and 35 healthy controls (HCs). Among them, 32 MG patients received immunoglobulin intravenous (IVIG) injections (0.4 g/kg per day for 5 consecutive days). IL-27 levels were collected before and after the treatments and subjected to a comparative study. Finally, we assessed the correlations of IL-27 levels with the clinical characteristics of MG. As a result, serum IL-27 levels were significantly higher in MG patients than those in the HCs. Meanwhile, significant reduction was detected after the IVIG treatment. IL-27 levels positively correlated with both MG activities of daily living and quantitative MG score. IL-27 may participate in the pathogenesis of MG and can be used as an early marker for the diagnosis and prognosis of MG. In addition, IL-27 can be used as a target for MG treatment through the regulation of specific immune signaling and maintaining immune homeostasis.
Direct Measurement of ΔK Transmitted to the Active Plastic Zone in Fatigue
Authors: Marci G. , Bachmann V.
Published: September 2020

Fatigue crack growth rates are generally correlated to the excursion of the stress-intensity factor, ΔK The presently active plastic zone ahead of the crack does not experience the total excursion of the calculated stress intensity for low R-ratios. The lower part of ΔK, for loading conditions with R ≦ 0.35, is cut off due to the influence of the plastic wake zone. The result is the transmission of a reduced stress-intensity range, ΔKred, to the active plastic zone. It is shown that the lower limit of the stress-intensity range transmitted to the active plastic zone, namely KLL, is on the average 0.085 Kmax for the materials and fatigue conditions used. Microstructural features associated with the formation of shear-lips and small flaws in the plane-strain region of the specimen can cause a large rise of KLL.

By making some rough assumptions about the opening stress-intensity factor, Kop, it is shown that there must occur substantial excursions of compressive strains and stresses in the active plastic zone for cycles with low R-ratios.

Arguments are presented that show that the parameter KLL can explain the continuing retardation as a crack propagates through the plastic overload zone.

It is shown that the load to open or close a fatigue crack at certain positions behind the crack front decreases with increasing distance from the crack front.
Experimental Method for Direct Evaluation of the J-Contour Integral
Authors: Read D. T.
Published: September 2020

A method for direct experimental evaluation of the J-contour integral has been developed and used to measure J as a function of strain in tensile panels of high-strength steel (σy = 900 MPa) under elastic-plastic loading conditions. The principle of the present method is to measure the integrand terms of J at suitable intervals along an appropriate contour and then to evaluate the integral. Because the resulting J values are based directly on the definition of J, no assumptions about the crack size or the stress-strain fields in the vicinity of the crack tip are necessary. This advantage is crucial in cases of very short cracks (less than 10 percent of the panel width), which are of special interest for structural applications. The integrand terms are measured with strain gages and linear variable differential transducers (LVDTs) placed on an appropriate contour surrounding the crack. Load, LVDT-displacement, strain-gage, and crack-mouth-opening-displacement measurements are acquired, stored, and printed at each deformation increment, and the J-integral is evaluated numerically by a minicomputer. J-integral values are plotted against the average specimen strain in real time. Directly measured J-integral values and values calculated using linear elastic fracture mechanics agreed within 12 percent for average strain values between 10 and 90 percent of yield. The experimental uncertainties become significantly less for strains of several times yield than for strains below yield. This technique has been used to measure J as a function of strain in edge-cracked and center-cracked tensile panels with short cracks at strains beyond yield, cases for which closed form solutions for J are not available.
Dynamic Fracture of Three Specimens
Authors: Kobayashi A. S. , Emery A. F. , Liaw B. M.
Published: September 2020

A dynamic finite-element code was used in its “application mode” to analyze the dynamic fracture responses of a single-edged-notch specimen subjected to fixed end rotation, a wedge-loaded single-edged-notch specimen, and an internally notched semicircular specimen subjected to end rotation and shear deformation. The dynamic fracture responses in each of the three specimens consisting of A533B steel, Homalite-100, or Araldite B photoelastic polymers were nearly identical despite the widely varying material properties. A scaling law for dynamic fracture of specimens with identical geometry and similar dynamic fracture toughness versus crack velocity relation, but with different material, is proposed. The numerical results also show that significant energy dissipation due to viscoelastic damping cannot possibly occur during the short duration of dynamic fracture.
Mixed-Mode Crack Growth Using the Compact Specimen
Authors: Miglin M. T. , Lin I. -H. , Hirth J. P. , Rosenfield A. R.
Published: September 2020

Combined Mode I and Mode III crack growth was examined for a high-strength low-alloy (HSLA) steel. Resolution of the shear and normal components of load and displacement of a modified compact tension specimen with the crack plane oriented at – 45 deg to the broad face showed that the shear (Mode III) contribution to toughness was dominant. Mode III toughness was more sensitive to strength than Mode I toughness. A dominance of crack growth behavior by the tendency toward shear instability is postulated.
Single Specimen J-Based Fracture Toughness Test for High-Strength Steels
Authors: Kapp J. A. , Underwood J. H.
Published: September 2020

A single specimen J-based fracture toughness test has been developed which results in accurate and reliable measurements for a high-strength low-alloy steel with several yield strengths. The specimen used is a deeply cracked Charpy specimen tested in slow, three-point bending. A simple plastic-stress analysis was performed which identifies a single point on the load displacement trace at which the J-integral is calculated as an estimate of KIc, The method can be applied inexpensively and may be used as a quality control measure of fracture toughness.
A Fracture Mechanics Study on Resistance of ASTM A36, A572, and A517 Grade F Structural Steels to Stress-Corrosion Crack Growth in Salt Water
Authors: Novak S. R.
Published: September 2020

The present study was conducted to evaluate the susceptibility of ASTM A36, A572, and A517 Grade F steels to stress-corrosion cracking (SCC) by using fatigue-pre-cracked specimens and principles of linear-elastic fracture mechanics (LEFM). Tests were conducted under total-immersion conditions in 3.5 percent sodium chloride (NaCl) solution maintained at + 22°C (+ 72°F) and pH ≅ 6.0. Single-edge-notched specimens were subjected to cantilever bending under conditions of constant dead-weight loading for test periods between 6000 and 16 000 h, or equivalently, between 8.5 months and nearly 2 years.

Results showed that these three steels exhibited a high relative fracture toughness level in air, KIx, and a high resistance to SCC as measured by the apparent level of SCC crack-growth threshold, “K*Iscc”; Each KIx and “K*Iscc” value corresponded to the application of either elastic-plastic or fully plastic stress levels that were well above the respective values of yield strength, σys.

These and earlier results, representing evaluation of eight different steels, demonstrate that structural steels in the strength range 210 to 900 MPa (30 to 130 ksi) are typically either immune or virtually immune to SCC crack growth in 3.5 percent NaCl solution. Such results were beyond the direct applicability of LEFM and were obtained despite the use of severe LEFM test conditions (sharp crack, high crack-tip stress, total immersion condition, and relatively long test durations).

Results of metallographic evaluation studies also are presented and discussed in relation to the tendency of various steels to exhibit crack extension (Δascc), crack-tip blunting, or transverse cracks or fissures or all three along the walls of the original machined notch and the original fatigue crack. Such metallographic examinations were conducted on steels from both the present and earlier studies. All such evaluations relate specifically to specimens at initial stress-intensity values, KIj, that were either at or below the respective SCC stress-intensity threshold, “K*Iscc,” for each steel.

The significance of these SCC results is discussed in relation to the generally more realistic conditions of cyclic loading (corrosion fatigue behavior) that often arc the controlling factors in the determination of useful structural life for components subjected to long-term environmental service.
Effect of Through-the-Thickness Stress Distribution upon Crack Growth Behavior in a Nickel-Base Superalloy
Authors: Ashbaugh N. E.
Published: September 2020

The object of this investigation was to determine the principal parameters which affect crack growth at elevated temperatures and under sustained loads. These results provide a better understanding for the development of crack growth models which improve the capability of predicting crack growth in materials which are used under extreme operating conditions such as those produced in gas turbine engines.

Crack growth behavior was investigated in a nickel-base superalloy (!NH)()) at 732°C in laboratory air under sustained load. The tests were conducted on side-grooved compact-type specimens. One of the purposes of the study was to evaluate the effect of the through-the-thickness stress distribution upon crack growth behavior in grooved specimens. Also in this study the effects of crack orientation and net thickness between the side grooves were evaluated.

The crack growth rates as a function of stress-intensity factor showed a slight dependence upon thickness and were independent of crack orientation. Also, the rates at the same stress-intensity level in the grooved specimens were faster than the rates in the smooth specimens, which indicated that the “plane-stress region” near the sides of the smooth specimen tends to retard the crack growth in the interior of the specimen. A model for the crack growth rates as a function of stress-intensity factor is presented. The model incorporates the dependence of growth rates upon initial loading conditions, and the effect of thickness and prior loading history can be taken into account in the model. The effect of overload ratios also is discussed.
Load Sequence Crack Growth Transients in a Superalloy at Elevated Temperature
Authors: Larsen J. M. , Nicholas T.
Published: September 2020

An experimental investigation was conducted to study crack growth transients produced when a sustained load hold time interrupts elevated temperature fatigue. Crack propagation testing of the superalloy INIOO was performed in air at 732°C for hold times ranging from 1 to 30 min, and the effects of load amplitude, specimen thickness, and frequency of fatigue cycling were examined. Using fractographic methods crack growth transients were observed for both sustained load crack growth following fatigue and fatigue crack growth following sustained loading. The beginning of the hold time was characterized by initially rapid crack growth that decayed to a steady-state behavior in approximately 5 min. Following the hold time, a retardation in crack growth rate was observed that partially counterbalanced the earlier, rapid crack growth. Compliance measurements used to monitor fatigue crack growth following a hold time underestimated the actual crack length as determined fractographically. In light of the observed crack growth transients associated with individual hold times, a discussion is presented of crack growth data generated under a loading sequence composed of short blocks of fatigue cycles separated by periodic hold times of short duration.
Use of a d-c Potential Drop Crack Monitoring Technique in the Development of Defect Tolerant Disk Alloys
Authors: Van Stone R. H. , Krueger D. D. , Duvelius L. T.
Published: September 2020

A direct current (d-c) potential drop technique can be used to monitor the growth of cracks from short 0.1-mm (0.004-in.)-deep electric discharge machined (EDM) defects. Two defect geometries have been developed, a chord-shaped defect approximately 1.6 mm (0.063 in.) wide on the surface and a semicircular notch approximately 0.2 mm (0.008 in.) wide. Due to its higher potential-crack depth sensitivity, the chord defect is used in totally elastic load control tests; however, it suffers from multiple nucleation, crack front tunneling at short crack lengths, and notch root radii dependent crack nucleation. These limitations restrict absolute determination of near-threshold crack growth rates, but this test still provides a relative measure of these properties. Cracks grown from semicircular EDM defects grow in a uniform fashion, and crack depths can be predicted from an analytic model. Using this type of test under a strain cycling mode provides an experimental determination of the residual fatigue life and the Region II fatigue crack growth rates. The crack growth rate curves from semicircular defect, strain control, and chord defect load control tests overlap, even though the net section stress often varies by 60 percent. This test method has been used as a screening test in the development of nickel-base superalloy disk materials with improved defect tolerance, that is, resistance to cyclic crack initiation and growth. The materials evaluated include René 95, IN718, and new experimental compositions. Using these tests, processing conditions that improved the defect tolerance of powder metallurgy Rene 95 by 30 percent have been identified. Study of fatigue crack growth curves of IN718 over a range of temperatures has helped to understand variations in the shape of conventional low-cycle fatigue curves.
Environmental Influences on the Fracture and Fatigue Properties of Titanium Metal-Matrix Continuous Fiber Composites
Authors: Mahulikar D. S. , Park Y. H. , Marcus H. L.
Published: September 2020

Mixed-mode tensile and fatigue crack propagation studies were carried out on B4C/B fiber reinforced Ti-6A1-4V-matrix composites for the as-received, vacuum heat-treated, and air heat-treated conditions. The vacuum heat treatment had minimal effect on the tensile properties of the composite but improved the fatigue crack propagation properties. The air heat treatment degraded the fibers and the interface, resulting in loss of longitudinal strength but improvement of fatigue crack propagation properties. The fatigue crack propagation for the mixed mode 30-deg, 45-deg, and transverse specimens was self-similar. The as-received composites' mixed-mode propagation is given by (da/dN) α (ΔG/Gf)m for all the fiber orientations showing self-similar crack propagation. Humid environments accelerated the fatigue crack growth considerably compared to the vacuum and inert gas environments. Failure stress intensity (KF) appeared to have a lower value in humid environments.
Electronic characteristics of CdS quantum dots with defects
Authors: Kupchak I. M. , Korbutyak D. V. , Serpak N. F.
Published: September 2020

Using the density functional theory and the generalized gradient approximation, we calculated the atomic structure, the density of electronic states, and the optical absorption spectra of CdS quantum dots containing intrinsic defects — a cadmium vacancy VCd and an interstitial sulfur atom SI, and substitutional impurities — zinc and copper in place of the atom cadmium — ZnCd and CuCd, respectively. The calculations were performed for the Cd33S33 cluster corresponding to the so-called “magic” size of the quantum dot. This size has a minimum of dangling bonds at the surface and allows the using of such a cluster without the passivation. The structural relaxation during the formation of such defects and the distribution of the wave function of the state corresponding to the top of the valence band are analyzed in details. It has been shown that the cadmium vacancy forms local states in the band gap of CdS nanocrystals, and can serve as centers of radiative recombination. Other defects form energy levels in the depths of the valence band or near its top, but whose energy positions do not correspond to the band maxima in the experimental photoluminescence spectra of CdS quantum dots, both undoped and doped with zinc. The calculated optical absorption spectra demonstrate a strong peak in the region of fundamental absorption of CdS for a cluster containing a substitutional impurity of CuCd, in contrast to other systems where no such peaks are observed. In addition, the replacement of the cadmium atom with copper leads to a decrease in the number of chemical bonds to three and, accordingly, to the largest relaxation among the systems studied. This feature is caused by the crystal structure inhomogeneity of copper sulfide CuxS, which, depending on stoichiometry, can be either a semiconductor or a metal.
Evolved Differences in cis and trans Regulation Between the Maternal and Zygotic mRNA Complements in the Drosophila Embryo
Authors: Cartwright Emily L , Lott Susan E
Published: September 2020

The critical processes of early development require gene products that mothers deposit into eggs, before the zygotic genome is transcriptionally activated. Here, Cartwright and Lott determine that patterns of gene regulatory evolution differ for transcripts .....
Sociological interpretation of social problems
Authors: Katsora Oleksandr
Published: September 2020

In the article, the author analyzes the main sociological approaches to dealing the social problems, their historical development. Social problems are one of the hottest topics of modern society, which requires consideration of sociological science. The topic of social problems gains special significance in the context of social and economic tensions in ukrainian society. Of course, that social problems are not a phenomenon, that is present exclusively in the crisis period, but their worsening and spreading occurs in difficult socio-economic conditions. Therefore, the aim of the article is to analyze the main traditional and modern sociological approaches to understanding social problems. To achieve this goal, a systematic analysis (to describe the phenomenon of social problems) and a comparative-historical method (to outline traditional and modern sociological approaches to understanding social problems) were used.The article considers such sociological approaches to social problems as social pathology, social disorganization, functional and critical approaches, the approach of value conflict, constructionsite approach and the approach of «labelling». Each approach has its own peculiarities of consideration of social problems, that is related with the historical period in which it arose and settled down, and the views of members of a particular sociological approach to social problems. Moreover, considering the basic sociological approaches to understanding social problems, there is a certain evolution of these views. Two sociological groups of approaches to social problems that approach their definition from the objectivist and subjectivist side are substantiated and singled out. Also, the article discusses the main advantages and disadvantages of sociological approaches to dealing the social problems.