bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of the Long-Sought Leptin in Chicken and Duck: Expression Pattern of the Highly GC-Rich Avian leptin Fits an Autocrine/Paracrine Rather Than Endocrine Function
Authors: Seroussi Eyal , Cinnamon Yuval , Yosefi Sara , Genin Olga , Smith Julia Gage , Rafati Nima , Bornelöv Susanne , Andersson Leif , Friedman-Einat Miriam
Published: November 2015

More than 20 years after characterization of the key regulator of mammalian energy balance, leptin, we identified the leptin (LEP) genes of chicken (Gallus gallus) and duck (Anas platyrhynchos). The extreme guanine-cytosine content (∼70%), the location in a genomic region with low-complexity repetitive and palindromic sequence elements, the relatively low sequence conservation, and low level of expression have hampered the identification of these genes until now. In vitro-expressed chicken and duck leptins specifically activated signaling through the chicken leptin receptor in cell culture. In situ hybridization demonstrated expression of LEP mRNA in granular and Purkinje cells of the cerebellum, anterior pituitary, and in embryonic limb buds, somites, and branchial arches, suggesting roles in adult brain control of energy balance and during embryonic development. The expression patterns of LEP and the leptin receptor (LEPR) were explored in chicken, duck, and quail (Coturnix japonica) using RNA-sequencing experiments available in the Short Read Archive and by quantitative RT-PCR. In adipose tissue, LEP and LEPR were scarcely transcribed, and the expression level was not correlated to adiposity. Our identification of the leptin genes in chicken and duck genomes resolves a long lasting controversy regarding the existence of leptin genes in these species. This identification was confirmed by sequence and structural similarity, conserved exon-intron boundaries, detection in numerous genomic, and transcriptomic datasets and characterization by PCR, quantitative RT-PCR, in situ hybridization, and bioassays. Our results point to an autocrine/paracrine mode of action for bird leptin instead of being a circulating hormone as in mammals.
Reducing Adiposity in a Critical Developmental Window Has Lasting Benefits in Mice
Authors: Lerea Jaclyn S. , Ring Laurence E. , Hassouna Rim , Chong Angie C. N. , Szigeti-Buck Klara , Horvath Tamas L. , Zeltser Lori M.
Published: November 2015

Although most adults can lose weight by dieting, a well-characterized compensatory decrease in energy expenditure promotes weight regain more than 90% of the time. Using mice with impaired hypothalamic leptin signaling as a model of early-onset hyperphagia and obesity, we explored whether this unfavorable response to weight loss could be circumvented by early intervention. Early-onset obesity was associated with impairments in the structure and function of brown adipose tissue mitochondria, which were ameliorated by weight loss at any age. Although decreased sympathetic tone in weight-reduced adults resulted in net reductions in brown adipose tissue thermogenesis and energy expenditure that promoted rapid weight regain, this was not the case when dietary interventions were initiated at weaning. Enhanced energy expenditure persisted even after mice were allowed to resume overeating, leading to lasting reductions in adiposity. These findings reveal a time window when dietary interventions can produce metabolic improvements that are stably maintained.
Central Diabetes Insipidus in Infancy With or Without Hypothalamic Adipsic Hypernatremia Syndrome: Early Identification and Outcome
Authors: Djermane Adel , Elmaleh Monique , Simon Dominique , Poidvin Amélie , Carel Jean-Claude , Léger Juliane
Published: November 2015

Context:

Neonatal central diabetes insipidus (CDI) with or without adipsia is a very rare complication of various complex hypothalamic disorders. It is associated with greater morbidity and a high risk of developing both hypernatremia and hyponatremia, due to the condition itself or secondary to treatment with vasopressin analogs or fluid administration. Its outcomes have yet to be evaluated.

Objective:

To investigate the clinical outcomes of patients with neonatal-onset CDI or adipsic CDI with hypernatremia.

Design, Setting, and Participants:

All patients diagnosed with neonatal CDI in a university hospital-based observational study and followed between 2005 and 2015 were included and analyzed retrospectively.

Main Outcome Measures:

The various causes of CDI were grouped. Clinical outcome and comorbidities were analyzed.

Results:

Ten of the 12 patients had an underlying condition with brain malformations: optic nerve hypoplasia (n = 3), septo-optic dysplasia (n = 2), semilobar holoprosencephaly (n = 1), ectopic neurohypophysis (n = 3), and unilateral absence of the internal carotid artery (n = 1). The other two were idiopathic cases. During the median follow-up period of 7.8 (4.9–16.8) years, all but one patient displayed anterior pituitary deficiency. Transient CDI was found in three (25%) patients for whom a posterior pituitary hyperintense signal was observed with (n = 2) and without (n = 1) structural hypothalamic pituitary abnormalities, and with no other underlying cerebral malformations. Patients with permanent CDI with persistent adipsia (n = 4) and without adipsia (n = 5) required adequate fluid intake and various doses of desamino-D-arginine-8-vasopressin. Those with adipsia were more likely to develop hypernatremia (45 vs 33%), hyponatremia (16 vs 4%) (P < .0001), and severe neurodevelopmental delay (P < .05) than those without adipsia. Comorbidities were common. The underlying cause remains unknown at the age of 23 years for one patient with CDI and normal thirst.

Conclusion:

Neonatal CDI may be transient or permanent. These vulnerable patients have high rates of comorbidity and require careful monitoring.
HiCUP: pipeline for mapping and processing Hi-C data
Authors: Wingett Steven W. , Ewels Philip , Furlan-Magaril Mayra , Nagano Takashi , Schoenfelder Stefan , Fraser Peter , Andrews Simon
Published: November 2015

HiCUP is a pipeline for processing sequence data generated by Hi-C and Capture Hi-C (CHi-C) experiments, which are techniques used to investigate three-dimensional genomic organisation. The pipeline maps data to a specified reference genome and removes artefacts that would otherwise hinder subsequent analysis. HiCUP also produces an easy-to-interpret yet detailed quality control (QC) report that assists in refining experimental protocols for future studies. The software is freely available and has already been used for processing Hi-C and CHi-C data in several recently published peer-reviewed studies.
A DNA extraction protocol for improved DNA yield from individual mosquitoes
Authors: Nieman Catelyn C. , Yamasaki Youki , Collier Travis C. , Lee Yoosook
Published: November 2015

Typical DNA extraction protocols from commercially available kits provide an adequate amount of DNA from a single individual mosquito sufficient for PCR-based assays. However, next-generation sequencing applications and high-throughput SNP genotyping assays exposed the limitation of DNA quantity one usually gets from a single individual mosquito. Whole genome amplification could alleviate the issue but it also creates bias in genome representation. While trying to find alternative DNA extraction protocols for improved DNA yield, we found that a combination of the tissue lysis protocol from Life Technologies and the DNA extraction protocol from Qiagen yielded a higher DNA amount than the protocol using the Qiagen or Life Technologies kit only. We have not rigorously tested all the possible combinations of extraction protocols; we also only tested this on mosquito samples. Therefore, our finding should be noted as a suggestion for improving people’s own DNA extraction protocols and not as an advertisement of a commercially available product.
Optimization and Simulation of Orthopedic Spine Surgery Cases at Mayo Clinic
Authors: Ozen Asli , Marmor Yariv , Rohleder Thomas , Balasubramanian Hari , Huddleston Jeanne , Huddleston Paul
Published: November 2015

Spine surgeries tend to be lengthy (mean time of 4 hours) and highly variable (with some surgeries lasting 18 hours or more). This variability along with patient preferences driving scheduling decisions resulted in both low operating room (OR) utilization and significant overtime for surgical teams at Mayo Clinic. In this paper we discuss the development of an improved scheduling approach for spine surgeries over a rolling planning horizon. First, data mining and statistical analysis was performed using a large data set to identify categories of surgeries that could be grouped together based on surgical time distributions and could be categorized at the time of case scheduling. These surgical categories are then used in a hierarchical optimization approach with the objective of maximizing a weighted combination of OR utilization and net profit. The optimization model is explored to consider trade-offs and relationships among utilization levels, financial performance, overtime allowance, and case mix. The new scheduling approach was implemented via a custom Web-based application that allowed the surgeons and schedulers to interactively identify best surgical days with patients. A pilot implementation resulted in a utilization increase of 19% and a reduction in overtime by 10%.
Active Postmarketing Drug Surveillance for Multiple Adverse Events
Authors: Goh Joel , Bjarnadóttir Margrét V. , Bayati Mohsen , Zenios Stefanos A.
Published: November 2015

Postmarketing drug surveillance is the process of monitoring the adverse events of pharmaceutical or medical devices after they are approved by the appropriate regulatory authorities. Historically, such surveillance was based on voluntary reports by medical practitioners, but with the widespread adoption of electronic medical records and comprehensive patient databases, surveillance systems that utilize such data are of considerable interest. Unfortunately, existing methods for analyzing the data in such systems ignore the open-ended exploratory nature of such systems that requires the assessment of multiple possible adverse events. In this article, we propose a method, SEQMEDS, that assesses the effect of a single drug on multiple adverse events by analyzing data that accumulate sequentially and explicitly captures interdependencies among the multiple events. The method continuously monitors a vector-valued test-statistic derived from the cumulative number of adverse events. It flags a potential adverse event once the test-statistic crosses a stopping boundary. We employ asymptotic analysis that assumes a large number of observations in a given window of time to show how to compute the stopping boundary by solving a convex optimization problem that achieves a desired Type I error and minimizes the expected time to detection under a pre-specified alternative hypothesis. We apply our method to a model in which the interdependency among the multiple adverse events is captured by a Cox proportional hazards model with time-dependent covariates and demonstrate that it provides an approximation of a fully sequential test for the maximum hazard ratio of the drug over multiple adverse events. A numerical study verifies that our method delivers Type I /II errors that are below pre-specified levels and is robust to distributional assumptions and parameter values.
The Reference Effects on a Retailer’s Dynamic Pricing and Inventory Strategies with Strategic Consumers
Authors: Wu Shining , Liu Qian , Zhang Rachel Q.
Published: November 2015

We consider a retailer that sells the same or different versions of the product season after season. At the beginning of each season (stage 1), the retailer places an order and sells the product at the full price. As the sales unfold, the retailer has an opportunity to mark down the price (stage 2), which creates an incentive for strategic consumers to delay their purchases for price discount. However, consumers do not know the markdown price exactly when they time their purchases; instead, they learn from the retailer’s past prices and form their estimate of the markdown price, called the reference price, to decide if they purchase at the full price or wait for the markdown in the current selling season. We characterize the properties of the optimal ordering and markdown decisions and show that markdowns, if adopted appropriately, do not necessarily destroy the stability of a business even in the presence of strategic consumers. Furthermore, the consumers' reference exhibits a mean reverting pattern under certain conditions; that is, the reference fluctuates around a mean value, reflecting the practice of most stable businesses. We conduct numerical studies to investigate the impact of consumer learning about the reference price and various system parameters on the retailer’s optimal strategies and profitability in the presence of strategic consumers.
Solitary Cysticercosis in Eye: Literature Review and A Hypothesis on Transmission of Infection
Authors: Sahu Priyadarshi Soumyaranjan , Ito Akira
Published: November 2015

Ophthalmic cysticercosis due to larval Taenia solium infestation in eye is one of the common preventable causes of acquired blindness particularly in the tropics. Though haematogenously disseminated oncospheres of this parasite can lodge in any tissue or body parts in human, there is a known predilection for brain, skeletal muscle and eye where they develop into metacestode larvae or cysticerci. However a number of cases have been reported having solitary cysticercosis only in eye without affecting brain and/or skeletal muscles. It is not clear to understand the exact route of entry into eye, the timing and environmental circumstances that produce ocular invasion without affecting other tissues. In this article, we have highlighted on the possibility of an alternate non-haematogenous route of transmission of infection particularly affecting eye or its adnexa in T. solium endemic tropical developing countries with poor sanitation practice, and deficient environmental monitoring system. Experimental infection studies might be helpful to prove the hypothesis on direct inoculation with T. solium eggs causing larval infestation in eye.
Age-Related Eyelid Diseases
Authors: Sevimli Neslihan , Karadag Remzi , Cakici Ozgur , Bayramlar Hüseyin
Published: November 2015

Although aging is natural and acceptable process by most people, it has become a major problem with increased life expectancy and socio-cultural levels. The eyelid protects eyes from dryness, environmental exposure and trauma. It is important that the eyelid is to be robust and in the proper position for eye health.
Beyond Gout: Colchicine Use in the Cardiovascular Patient
Authors: Campbell Kristen Bova , Cicci Teresa A. , Vora Alyssa K. , Burgess Lindsey D.
Published: November 2015

Colchicine is one of the oldest medications still in use today and is commonly used for the treatment of gout and familial Mediterranean fever. Its anti-inflammatory properties have raised the question of its utility in managing several cardiovascular diseases, including postoperative atrial fibrillation and pericarditis. This article will review the evidence for colchicine in these conditions and provide recommendations for use.
Gefitinib and Sonidegib
Authors: Medler Corey J. , Waddell J. Aubrey , Solimando Dominic A.
Published: November 2015

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases.
Biosimilars Are Here: A Hospital Pharmacist's Guide to Educating Health Care Professionals on Biosimilars
Authors: Jarrett Steven , Dingermann Theodor
Published: November 2015

Background

Pharmacists are the recognized experts in pharmacotherapy. With the recent introduction of biosimilar agents into the US market, pharmacists are poised to play a pivotal role in evaluating their risks versus benefits within the framework of cost containment.

Purpose

This article provides hospital pharmacists with the necessary information on the principles surrounding the development, approval process, and use of biosimilars.

Methods

Information contained in this article enables hospital pharmacists to identify concerns relating to biosimilars, implement educational components, and successfully evaluate biosimilars for the addition to the formulary. Additionally, this article reviews the European experience with biosimilars, the US Food and Drug Administration approval process, and postauthorization safety and pharmacovigilance programs.

Conclusion

It is important to educate health care providers about the differences between biosimilars and their reference biologics. The adoption of biosimilars is necessary to control long-term costs of biologics, increase patient access to care, and encourage innovation.
Risk Factors for Bleeding in Hospitalized Patients with Elevated INR: No Vitamin K Therapy Received versus Vitamin K Received
Authors: Mounce Monique , Essel Candace , Kim Tiffany , Harris Che Matthew
Published: November 2015

Background

Supratherapeutic international normalized ratio (INR) in patients on warfarin is a common side effect. Updated guidelines recommend against using vitamin K to correct INRs 4.5 to 10 in the absence of bleeding. The impact of compliance with updated guidelines during hospitalization has not been fully explored.

Methods

A retrospective, observational study was performed utilizing electronic medical records. The goal was to evaluate management of supratherapeutic INR values for medicine inpatients and identify differences in clinical outcomes among inpatients treated and not treated with vitamin K. Records from adult inpatients with at least one INR value between 4.5 and 9 were reviewed. A total of 51 records were evaluated. Thirty-four patients did not receive vitamin K compared to 17 who did. Bleeding events, readmissions rates, length of stay, and familiarity with new guidelines were studied.

Results

Mean age of patients was 73 years, and 71% were female. No statistically significant differences were observed in bleeding events between patients who received vitamin K and those who did not: 2/17 (12%) and 1/34 (3%), respectively ( P = .30). No differences in 30-day readmission rates (24% vs 18%; P = .71) or in length of stay (7 vs 4 days; P = .11) were found. All pharmacists (13 of 13) were familiar with CHEST 2012 guidelines on the management of supratherapeutic INR compared to 10 of 21 (48%) hospitalists ( P = .001).

Conclusions

With the national focus on reduction of health care costs, health systems are looking at innovative ways to reduce readmission rates and length of stay. This study, which evaluated the use of vitamin K administration, showed no statistical difference between bleeding events, readmission rates, and length of stay in patients who received vitamin K. Education on the updates of guidelines may be beneficial, as many providers were not familiar with the changes in recommendations.
Evaluation of the Safety of a Vancomycin Nomogram Used to Achieve Target Trough Concentrations
Authors: O'Brien Kristen A. , Mok Steve
Published: November 2015

Background

Dosing vancomycin to achieve target concentrations of 15 to 20 mg/L has been recommended for select infections. To date, few vancomycin nomograms designed to target these higher concentrations have been published, and only one has been published in North America. Based on the success of this nomogram in developing empiric vancomycin regimens that achieve higher target trough concentrations with low rates of nephrotoxicity, a vancomycin nomogram targeting concentrations of 15 to 20 mg/L was developed and implemented at Emory University Hospital and Emory University Hospital Midtown.

Objective

To evaluate the impact of a vancomycin-dosing nomogram on the incidence of vancomycin- associated nephrotoxicity and the time to achieve targeted trough concentrations.

Methods

A retrospective chart review of 200 patients who received vancomycin dosed to achieve target trough serum concentrations of 15 to 20 mg/L was performed.

Results

After implementation of the vancomycin nomogram, no statistically significant difference in incidence of vancomycin-associated nephrotoxicity was found (14% vs 16%; P = .197). Fewer patients had an initial vancomycin trough concentration within target range (29.1% vs 21.7%; P < .001). Adherence to the nomogram was poor, with only 41% of patients being dosed per the nomogram's recommendations.

Conclusion

Based on our results, implementation of a vancomycin dosing nomogram had no impact on the incidence of nephrotoxicity, and significantly fewer patients had an initial vancomycin trough within the target range of 15 to 20 mg/L. The clinical utility of a vancomycin dosing nomogram is still to be determined.
Bradycardia after Intravenous Ondansetron with Asystole on Rechallenge: A Case Report
Authors: Rapp Jonathan H. , Yuen Meggie , Abraham Teena
Published: November 2015

Purpose

There have been 3 published reports (4 cases) of symptomatic sinus bradycardia occurring after intravenous (IV) administration of the selective 5-hydroxytryptamine 3 (5-HT3) receptor antagonist ondansetron. We report a fifth case in which the patient developed asystole after rechallenge with ondansetron.

A 36-year-old pregnant patient with no cardiac history, status post cerclage for cervical insufficiency, experienced nausea in the post ambulatory care unit after administration of morphine and indomethacin for pain. After IV administration of ondansetron, the patient's heart rate decreased to the 40s and improved spontaneously. The patient experienced a second episode of nausea, another dose of ondansetron was administered, and the patient went into asystole. Advanced cardiac life support measures were initiated and chest compressions were conducted for 3 minutes with return of spontaneous circulation. The patient was monitored overnight with no development of new cardiac arrhythmias and was discharged from the hospital in stable condition.

Conclusions

Sinus bradycardia after IV administration of ondansetron was observed in a 36-year-old pregnant patient status post cerclage. On rechallenge, the patient went into asystole. This case report adds to the available literature regarding ondansetron-induced cardiac arrhythmias and the possibility of asystole upon rechallenge.
A evolução do conceito de risco à luz das ciências naturais e sociais
Authors: Souza Kátia Regina Góes , Lourenço Luciano
Published: November 2015

O presente artigo visa desenvolver uma breve revisão acerca da evolução do conceito de risco, tendo como percursoraa teoria global trazida à baila por Ulrich Beck e Anthony Giddens. O conceito de risco tem diferentes significados noâmbito das ciências sociais e naturais. Entretanto, envolto pela premente questão ambiental, o conceito vem sendoaperfeiçoado com o passar do tempo. Deste modo, entende-se ser importante resgatar sua trajetória sob diferentesabordagens científicas, visando compreender seus desdobramentos nos dias atuais e futuros.
Transvases do rio São Francisco: riscos sociais para os moradores da Vila Junco em Cabrobó (PE) – Brasil
Authors: Assis André Tomé de , Lourenço Luciano , Tubaldini Maria Aparecida Dos Santos
Published: November 2015

Os transvases do rio São Francisco correspondem a um conjunto de obras, sob a responsabilidade do Ministério da Integração do Brasil. A sua inauguração está prevista para este ano de 2015, com o objetivo de diminuir os problemas da seca na região nordeste do país. Durante a realização das obras, as populações rurais tiveram de ser realocadas e foram submetidos a uma série de riscos sociais que merecem ser analisados, usando como metodologia a história oral, a qual permitiu a sua recolha e apresentação.
Vulnerabilidade socioespacial na planície de inundação na cidade de Aquidauana / MS – Brasil
Authors: Fernandes Elvira Fátima De Lima , Anunciação Vicentina Socorro da , Silva Jaime Ferreira da
Published: November 2015

Localizada no estado de Mato Grosso do Sul, a sede municipal de Aquidauana tem sofrido com a materialização de inundações sucessivas. O objetivo do trabalho foi realizar a análise socioespacial e ambiental na planície de inundação, utilizando-se técnicas de mapeamento e entrevistas junto à população. Os resultados apontam o aumento eminente das inundações, número de residências, topofilia, danos materiais, prejuízos econômicos e sociais.
Riscos resultantes da atuação antrópica na constituição de aterros. Os grandes aterros do concelho do Funchal
Authors: Araújo Duarte Nuno Gouveia , Roxo Maria José , Silva João Baptista Pereira
Published: November 2015

Existem na Ilha da Madeira inúmeros aterros formados por materiais de escavação e de construção. As investigações realizadas permitiram definir os níveis de vulnerabilidade, de perigosidade e de risco dos vinte e dois principais aterros de média e grande dimensão no concelho do Funchal. Pretende-se que os resultados obtidos e os elementos de suporte apresentados sirvam de base à decisão, promovendo a tomada de medidas sobre a localização, monitorização e manutenção dos antigos e atuais aterros, reduzindo o grau de risco para a população e o meio ambiente.
Políticas publicas de preservação histórica: diagnóstico de risco dos imóveis tombados na cidade de Bauru/SP Brasil
Authors: Losnak Sérgio Ricardo , Lopes Camila Santos Doubek
Published: November 2015

Este trabalho objetiva diagnosticar os agentes de riscos que contribuem para a descaracterização do patrimônio histórico local e a relação existente entre preservação e a forma de uso e ou abandono. Para alcançar os resultados foi empregada pesquisa quali-quantitativa, bibliográfica exploratória e documental, assim como visitas técnicas a cada um dos bens. Os resultados alcançados mostram os agentes que contribuem para a descaracterização dos bens tombados, levando a conclusão que o fato de um bem estar tombado não garante a sua preservação.
A mercantilização da natureza e o aquecimento global: o papel da mídia
Authors: Junior Paulo Cesar Zangalli , Neto João Lima Sant’Anna
Published: November 2015

A proposta deste artigo é debater como o discurso ambiental tem sido incorporado pelo capital num processo de ambientalização e mercantilização da natureza com enfoque na construção e divulgação do discurso das mudanças climáticas globais pela mídia. A forma como a mídia divulga o tema, amplia e maximiza a perceção do risco e, muitas vezes, recria a realidade. Como considerações, aponta-se que a mídia atua como um agente legitimador de agendas públicas sobre as mudanças climáticas e, ao generalizar os discursos, contribui para a mercantilização do clima.
Risco de galgamento nas estruturas marítimas da praia da Vitória: resultados do sistema HIDRALERTA
Authors: Fortes C. J. E. M. , Reis R. , Reis M. T. , Poseiro P. , Craveiro J. , Santos J. A.
Published: November 2015

O sistema HIDRALERTA é um sistema de previsão, alerta e avaliação de risco associado ao galgamento e inundação em zonas costeiras e portuárias, tendo como ideia base a utilização de medições/previsões da agitação marítima, para calcular os seus efeitos em termos de galgamentos e inundações. Este trabalho descreve a componente Avaliação do Risco do sistema HIDRALERTA e apresenta aplicações ao porto e baía da Praia da Vitória, ilustrando as potencialidades do mesmo.
Aumento das inundações urbanas nas capitais da região do Sahel
Authors: Nouaceur Zeineddine
Published: November 2015

Com as mudanças climáticas observadas nos últimos anos e o retorno das chuvas, as grandes cidades do Sahel estão agora enfrentando grandes inundações urbanas. Muitos bairros "legais" e "ilegais" provaram ser verdadeiras armadilhas, muitas vezes perigosas e inóspitas, que às vezes forçam o abandono imediato de algumas das áreas de residenciais (por exemplo, as áreas de Nouakchott e Dakar). Este trabalho de pesquisa tem como objetivo mostrar, inicialmente, mudanças climáticas observadas nesta faixa do Sahel, e em segundo lugar, a vulnerabilidade e esiliência das três capitais da África Ocidental (Nouakchott, Dakar e Ouagadougou) a essas novas condições climáticas.
Полное решение уравнений Янга-Миллса для центрально-симметрической метрики
при наличии электромагнитного поля
Authors: Кривоносов Леонид Николаевич , Krivonosov Leonid Nikolaevich , Лукьянов Вячеслав Анатольевич , Lukyanov Vyacheslav A
Published: November 2015

Ранее авторами было найдено полное решение уравнений Янга-Миллса для центрально-симметрической метрики в 4-мерном пространстве конформной связности без кручения при отсутствии электромагнитного поля. Позже, в другой статье, авторы нашли решения уравнений Янга-Миллса для этой же метрики при наличии электромагнитного поля специального вида, предполагая, что его компоненты зависят не от четырех, а только от двух переменных. Там же авторы провели сравнение получившегося решения с хорошо известным решением Райсснера-Нордстрема и указали причину того, что эти решения не совпадают. В настоящей работе авторы не накладывают никаких предварительных ограничений на компоненты электромагнитного поля. Это сильно усложняет вывод уравнений Янга-Миллса. Тем не менее, все вычислительные трудности были преодолены. Оказалось, что решения этих уравнений всe равно зависят только от двух переменных, и новых решений, кроме полученных ранее, не возникает. Авторы делают вывод, что найдены все решения уравнений Янга-Миллса для центрально-симметрической метрики при наличии произвольного электромагнитного поля, согласованного с уравнениями Янга-Миллса в пространстве без кручения (то есть без источников). Эти решения выражаются через эллиптическую функцию Вейерштрасса.
Решение трехмерных уравнений теплопроводности с помощью разрывного метода Галeркина
на неструктурированных сетках
Authors: Жалнин Руслан Викторович , Zhalnin Ruslan V. , Ладонкина Марина Евгеньевна , Ladonkina Marina Eugenievna , Масягин Виктор Федорович , Masyagin Victor Fedorovich , Тишкин Владимир Федорович , Tishkin Vladimir Fedorovich
Published: November 2015

Для решения уравнений диффузионного типа в настоящее время широко применяется конечно-элементный метод Галeркина с разрывными базисными функциями (РМГ), который характеризуется высоким порядком точности получаемого решения. Для применения РМГ исходное уравнение второго порядка преобразуется к системе дифференциальных уравнений в частных производных первого порядка. Для этого вводятся вспомогательные потоковые переменные. В соответствии с традиционным подходом в РМГ решение в каждой ячейке основной сетки представляется в виде линейной комбинации базисных функций. Тепловой поток ищется в виде линейной комбинации базисных функций на ячейках двойственной сетки. Двойственная сетка состоит из медианных контрольных объемов, построенных относительно вершин основной сетки. Интегрирование по объемам и граням ячеек базируется на использовании квадратурных формул Гаусса. Численный алгоритм рассматривается на примере решения начально-краевой задачи для трехмерного уравнения теплопроводности.
Численная методика реализована в виде программного продукта и ориентирована на решение трехмерных задач теплопроводности на неструктурированных тетраэдральных сетках. В работе представлены результаты расчетов ряда тестовых задач, демонстрирующие возможности и точность методики.
A multi-perspective analysis of free dress code at high schools
Authors: Kapucu Seher , Sezgin Ferudun
Published: November 2015

The purpose of this study is, through a multi-perspective approach, to analyze free dress code at high schools from the views of students, teachers, parents and school administrators. In this qualitative research, maximum variation and criterion sampling methods were used to select participants. Data were collected through semi-structured interview forms, which were developed separately for each study group. Interviews were conducted face'to-face on an individual basis. The participants consisted of 28 students, 23 teachers, 19 parents and 9 school administrators. Data were audio-taped, and notes were taken during the meetings. Data were analyzed descriptively most of the participants stated that the main purpose of free dress code at high schools was to make students move around comfortably. Although most of students were likely to support free dress code, most of the other participants tended to support the school uniform. Free dress code was perceived as an economic burden by many participants, and it was described as a threat against school safety and discipline. It was recommended that issues on school dress code policies should be comprehensively and sensitively considered from multiple perspectives.
Evaluation of Quran courses curriculum (4-6 age group ) in the context of religious development theories
Authors: Tosun Cemal , Çapcıoğlu Fatma
Published: November 2015

It is known that the children ask questions about religion, interest in religious behavior and activities /rituals since 3-4 years old. Therefore, these ages can be regarded as the critical period for religious development. In addition to the general characteristics of the children of this period, it is also important to know about the characteristics of the children's religious development in respect of religious education. This paper aims to examine and evaluate the Quran courses curriculum (4- 6 age of group) which has been applied in some provinces in Turkey since 2013-2014 academic year, in context of religious development theories. Compatibility of aims, attainments, stories, activities of the curriculum to the religious development has been discussed. In conclusion, it is seen that, despite some of its lacks, the curriculum has been prepared by taking the studies in the field of religious development into consideration. However, the characteristics of religious development have been overlooked at some points of curriculum due to the influence of subject- centered approach and tradition.
Antriebsregelungen mit stochastischen Störungen
Authors: Ströle D.
Published: November 2015

Die Auswirkungen stochastischer Störeinflüsse aufgeschlossene Antriebsregelkreise werden in Abhängigkeit von Störart und Kreisstruktur quantitativ untersucht. Daraus lassen sich Richtlinien für die Bemessung der Regelparameter gewinnen, um die Forderungen von dynamisch hochwertigem Führungsverhalten und weitgehender Störwertunterdrückung zu kombinieren.
Beispiele für adaptive Prozeßsteuerungen bei bekannter Struktur des Prozeßmodells
Authors: Popović D. B.
Published: November 2015

Die Prozeßoptimierung nach einem vorgegebenen Gütekriterium und die adaptive Prozeßsteuerung unter veränderlichen Umgebungsbedingungen stellen Automatisierungsziele dar, die mit einem Prozeßrechner durchgeführt werden können. Zu diesem Zweck müßte das dynamische mathematische Prozeßmodell im Rechner voreingespeichert zur Verfügung stehen. Als entscheidende Schwierigkeit auf diesem Wege erweist sich die Ermittlung des genannten Modells, da es sich dabei im allgemeinen um multivariable, nichtlineare Systeme mit verteilten Parametern handelt. Deshalb wird gegenüber dem dynamischen das statische mathematische Modelt bevorzugt, in dem nur die Modellstruktur als fest gegeben betrachtet wird, die variablen Modellparameter dagegen fortlaufend anhand von Meßdaten ermittelt werden. Somit kann das Modell ständig in Übereinstimmung mit dem augenblicklichen Zustand des Prozesses gebracht und zur optimalen Prozeßführung als ein prädiktives Prozeßmodell mit Eigenschaften zum Lernen angewendet werden.

Einige mathematische Verfahren, die sich zur Auswahl der Modellstruktur sowie zur „on-line“ - Ermittlung seiner Parameter besonders eignen, werden erörtert und ihre Anwendung zur Steuerung industrieller Prozesse an drei praktischen Beispielen wird demonstriert.
Der Einfluß von Reduzierstücken auf den Durchflußkennwert der Stellventile
Authors: Baumann H. D.
Published: November 2015

Reduzierstücke vor und hinter dem Stellventil, dessen Nennweite kleiner ist als die Nennweite der Rohrleitung, verringern die effektive Durchflußkapazität. Es wird ein Rechenverfahren .sowohl für den unterkritischen als auch für den überkritischen Strömungsfall angegeben, wonach sich der kv-Zuschlag für das mit Reduzierstücken versehene Stellventil leicht bestimmen läßt.
Übertragung von Verfahren der erweiterten harmonischen Linearisierung der Nichtlinearitäten in den Frequenzbereich
Authors: Ott M.
Published: November 2015

Es werden die bei [ 1] erweiterten Verfahren der harmonischen Linearisierung für unsymmetrische Schwingungen der Nichtlinearitäten in den Frequenzbereich übertragen. Dabei sind die unsymmetrischen Selbst Schwingungen (Grenzschwingungen) und Erregungsfrequenzgänge bei gleichzeitig vorhandenen langsamen Regelsignalen sowie deren getrennten Verstärkungen (Beschreibungsfunktionen und Verschiebungsfunktionen) aus dem aufgeschnittenen Regelkreis ermittelt.

Beispiele zeigen das Vorgehen bei Regelkreisen mit auch mehreren Nichtlinearitäten.
Sicherung von Prozeßrechneranlagen
Authors: Winkler O.
Published: November 2015

Im Rahmen dieses Beitrages werden Aspekte geeigneter Maßnahmen aufgezeigt, die bei der Instrumentierung von Prozeßrechneranlagen getroffen werden können, um verfahrenstechnische Prozesse gegen einen jederzeit möglichen Rechnerausfall zu sichern.
Über die optimale Synthese nichtlinearer Abtastregelungssysteme
Authors: Pokoski J. L.
Published: November 2015

Es wird ein Verfahren von J. Meksawan und G. J. Murphy zur optimalen Synthese einer Klasse nichtlinearer Abtastregelungssysteme kritisch untersucht und anhand eines Gegenbeispiels gezeigt, daß die entstehende Strategie nicht notwendig optimal ist.
Die Anwendung der Theorie der optimalen Filter auf die Synthese nichtlinearer Regelkreise, Teil I
Authors: Birnstiel K.
Published: November 2015

Bei gewissen nichtlinearen Regelkreisen mit stochastisch verlaufenden Eingangsgrößen erlaubt die Wienersche Theorie der optimalen Filter die Bemessung des optimalen linearen Reglers. An einem Regelkreis, der als Nichtlinearität einen Zweiseitenbegrenzer enthält, bei dem aber durch Einführen einer Nebenbedingung praktisch lineares Verhalten des Kreises zu erzwingen ist, wird das Optimierungsverfahren abgeleitet. Unter Anwendung eines Linearisierungsverfahrens werden die Betrachtungen auf den nichtlinear arbeitenden Regelkreis ausgedehnt.
Zur Synthese von Abtastsystemen im Frequenzbereich, Teil 1
Authors: Latzel W.
Published: November 2015

Es wird ein Syntheseverfahren zur Bestimmung der Koeffizienten eines Abtastreglers beschrieben, das auf dem für stetige Systeme bewährten Frequenzkennlinienverfahren aufbaut. Das Ergebnis der einfachen und übersichtlichen Dimensionierung sind überschwingungsfreie Regelorgänge, die für Regelstrecken ab der zweiten Ordnung gute Ergebnisse zeigen. Gegenüber dem Verfahren der „dead beat response“ sind die hiermit erzielten Ausregelzeiten etwa 40% größer, während die quadratische Regelfläche nur um 15 bis 20% größer ist. Das Verfahren eignet sich für Regelstrecken mit einer Ordnung größer oder gleich zwei und für Abtastregler mit einer Ordnung kleiner oder gleich drei, wobei die Ordnung des Reglers nicht größer als die Ordnung der Strecke sein darf. Damit eignet sich das dargestellte Verfahren vorwiegend für die in der technischen Anwendung häufig auftretenden Fälle.
Inkrementrechenschaltungen, Aufbau und Fehleruntersuchungen
Authors: Klapdor W.
Published: November 2015

Dieser Beitrag behandelt die Anwendung eines Inkrementrechnerbausteinsystems für die Rechenoperationen Addition, Subtraktion, Multiplikation, Division, Potenzieren und Radizieren sowie die Bildung der Exponential- und Logarithmusfunktion. Die prinzipiellen Fehlerquellen dieser Rechenschaltungen werden untersucht und - soweit in diesem Rahmen möglich Verfahren zur Verringerung der Abweichungen angegeben. Die Genauigkeit der Ergebnisse wird anhand zweier Beispiele uberprüft.
Zur Bestimmung von periodischen Zuständen in Regelungssystemen mit mehreren nichtlinearen Gliedern
Authors: Pandit M.
Published: November 2015

Eine Methode für die genaue Berechnung von periodischen Zuständen in Relaisregelungssystemen mit zusätzlichen nichtlinearen Gliedern wird angegeben. Sie geht von Gedanken aus, die von Harne!, Lurje und Zypkin für die Untersuchung von Systemen, die als einziges nichtlineares Glied ein Relaisglied enthalten, verwendet wurden. Weiterhin wird eine verbesserte Beschreibungsfunktion für Systeme mit zwei oder mehr Kennliniengliedern angegeben, die insbesondere auch dann gilt, wenn zwischen den Kennliniengliedern keine Tiefpässe liegen.
Die Bestimmung von suboptimalen beschränkten Steuerfolgen bei linearen zeitinvarianten diskreten Systemen
Authors: Hartmann I.
Published: November 2015

Für lineare zeitinvariante diskrete Systeme wird die beschränkte Eingangsfolge so bestimmt, daß jeder Zustand des Systems mindestens subzeitoptimal (fast optimal) in den Null-Zustandgeführt wird. (In dieser Arbeit wird das nur für reelle Eigenwerte der Systemmatrix gezeigt.) Das subzeitoptimale Verfahren ergibt sich aus der Untersuchung des Aufbaus von zeitoptimalen beschränkten Steuerfolgen.

Das Verfahren besteht aus zwei Teilen. Zustände x(1) mit einer großen Entfernung vom Null-Zustand werden in nicht mehr als (Ν + mopt) Abtastintervallen in den Ursprung gebracht (Ν Ordnung des Systems, mopt Anzahl der Abtastintervalle der zeitoptimalen Folge). Zustände x(1) in der Nähe des Null-Zustandes werden mit einer zeitoptimalen Folge in den Ursprung geführt.

Das vorgeschlagene Verfahren benötigt gegenüber den bisherigen zeitoptimalen Verfahren, insbesondere bei einer großen Anzahl von Abtastintervallen und hoher Ordnung des Systems ( Ν > 3), einen wesentlich geringeren Daten- und Zeitaufwand.
Regelgüte und Stabilität von Regelsystemen mit Prozeßrechnern bei Beschränkung der Stellgrößenänderungen
Authors: Schöne A.
Published: November 2015

Verschiedene verhältnismäßig häufig benutzte Methoden der Ausgabe von Stellsignalen bei der direkten digitalen Regelung (DDC) enthalten Begrenzungen der Stellgrößenänderungen. Das führt zu besonderen Formen nichtlinearen Verhaltens in DDC-Regelkreisen, die anhand verschiedener Beispiele erläutert werden. Hieraus folgt unter anderem ein heuristisch abgeleitetes Stabilitätskriterium für Systeme mit numerischen Approximationen analoger PID-Algorithmen und eine neuartige zeichnerische Darstellung derartiger Regelvorgänge. Auch wird die Leesche Regel über die Wahl der Abtastintervalle bei Regelstrecken mit Totzeit hinsichtlich ihrer Gültigkeitsgrenzen untersucht, und verschiedene andere, aus der Literatur bekannte Effekte bei DDC-Regelungen werden gedeutet.
Über die erforderliche Genauigkeit der Frequenzgänge von Regelstrecken
Authors: Isermann R.
Published: November 2015

Die erforderliche Genauigkeit der Frequenzgänge von Regelstrecken wird im Hinblick auf die Berechnung des Verhaltens des geschlossenen Regelkreises (Stabilitätsgrenze, Regelgüte, Einstellung der Reglerparameter) für Regelstrecken bis achter Ordnung mit P-, PI- bzw. PID-Reglern angegeben.

Je kleiner die Ordnungszahl ist, desto größer ist der genau zu ermittelnde Bereich des Frequenzganges der Regelstrecke. Bei Reglern mit D- Verhalten ist dieser Bereich am größten.
Entfaltungsalgorithmen zur Anwendung in der DDC-Technik
Authors: Reiner A. , Weber W.
Published: November 2015

Es werden spezielle Lösungen für den Entwurf von nichtkonventionellen DDC-Steuerungsalgorithmen für lineare Prozesse angegeben. Den Ausgangspunkt des Entwurfs bildet das der Steuerstrecke zugeordnete Faltungsintegral, dessen Entfaltung die Berechnung einer zur Erzeugung eines bestimmten Übergangsvorgangs notwendigen Eingangsgröße gestattet. Zwei verschiedene Typen von Algorithmen werden angegeben. Beim ersten Typ muß das Verhalten der Steuerstrecke in mathematisch geschlossener Form gegeben sein. Beim zweiten Typ dagegen ist nur die Kenntnis der numerischen Werte der für das System charakteristischen Funktion (z. B. Sprungantwort) erforderlich. In beiden Fällen läßt sich in einfacher Weise die Begrenzung der Stellgröße berücksichtigen.
Regelvorgänge mit pneumatischen Abtastreglern an verfahrenstechnischen Regelstrecken mit Totzeit
Authors: Rathert H.
Published: November 2015

Für Regelstrecken 1. und 2. Ordnung mit Totzeit wurden vier Abtastregler inbezug auf Stör- und Führungsverhalten mit einem kontinuierlichen Regler verglichen. Die Berechnung erfolgte mit Hilfe der Z-Transformation. Außerdem wurde der größte Verstärkungsfaktor eines jeden Abtastreglers in Abhängigkeit des Zeitkonstantenverhältnisses T1/Tt dargestellt.

Aus pneumatischen Logikschaltern und Verstärkern wurden pneumatische Abtastregier mit Schieberegistern für analoge pneumatische Signale im Bereich von 0,2 bis 1 atü gebaut sowie eine Regelanordnung mit Totzeitkompensation nach O. J. M. Smith pneumatisch verwirklicht.

An einer pneumatischen Modellregelstrecke und an zwei betrieblichen Regelstrecken mit Totzeit wurden praktische Regelungen durchgeführt.
Ein einfaches Verfahren zur Kennwertermittlung von Regelstrecken mit bekannter Struktur
Authors: Skala K.
Published: November 2015

Es wird ein Verfahren entwickelt, das es erlaubt, die Koeffizienten der Übertragungsfunktion einer Regelstrecke zu bestimmen. Der Typ der Übertragungsfunktion muß als bekannt vorausgesetzt werden. Der Grundgedanke des Verfahrens liegt darin, daß die Regelstrecke durch bestimmte Regler jeweils zu einem Regelkreis zusammengeschaltet wird. Die Reglerparameter werden kritisch eingestellt, so daß sich Eigenschwingungen ausbilden. Anhand der kritischen Parameterwerte und der entsprechenden Eigenfrequenzen lassen sich die Koeffizienten der Übertragungsfunktion formelmäßig bestimmen.
Ermittlung der Übertragungsfunktion aus dem gemessenen Amplituden- und Phasengang
Authors: Feindt E.-G.
Published: November 2015

Es wird ein Verfahren beschrieben, nach dem die Übertraglingsfunktion eines linearen Übertragungsgliedes aus dem gemessenen Amplituden- und Phasengang ermittelt werden kann. Dabei handelt es sich um ein Interpolationsverfahren, das im Fall eines streng linearen Übertragungsgliedes und fehlerfreier Messungen die exakt richtige Übertragungsfunktion ergibt. Die Interpolationskurve läuft bei hohen und niedrigen Frequenzen in die Asymptoten des Amplitudenganges ein.
Subzeitoptimale Steuergesetze für lineare zeitinvariante Systeme mit beliebiger Ordnung und beschränkter Steuergröße
Authors: Hartmann I.
Published: November 2015

Die Struktur von zeitoptimalen Steuergesetzen für kontinuierliche lineare zeitinvariante Systeme mit verschiedenen reellen Eigenwerten wurde untersucht. Aufgrund dieser Kenntnisse kann am Schluß der Arbeit ein subzeitoptimales Steuergesetz angegeben werden.

Das Steuergesetz, das zu einem System n-ter Ordnung gehört, baut sich aus den Steuergesetzen von (n - 1) Teilsystemen 2. Ordnung auf. Die Teilsysteme sind so geordnet, daß das erste Teilsystem, zu dem die Eigenwerte λ1 und λ2 der Systemmatrix A mit dem kleinsten Absolutbetrag gehören, den ersten Zeitabschnitt der zeitoptimalen Steuerfunktion u* (t) im wesentlichen bestimmt. Teilsysteme, zu denen Eigenwerte mit größerem Absolutbetrag gehören (es gilt hier λn < λn-1... < λ2 < λ1 ≤ 0), haben im allgemeinen einen kleineren Einfluß auf die Bestimmung von u* (t). Das (n - 1 )-te Teilsystem mit den Eigenwerten λn-1 und λn beeinflußt hauptsächlich den vorletzten Zeitabschnitt von u* (t). Am Ende dieses Abschnittes haben alle Zustandskomponenten den gleichen Zeitabstand vom Ursprung, so daß im letzten Zeitabschnitt alle Teilsysteme die gleiche Steuerfunktion liefern.

Die in dieser Arbeit gewählte Darstellung erlaubt außerdem eine einfache geometrische Ableitung des Satzes von Feldbaum.
Parameter-Identifizierung nach der Methode der kleinsten Quadrate — ein Überblick V.Krebs Darmstadt
Authors: Krebs V. , Thöm H.
Published: November 2015

Die Parameterschätzung nach der Methode der kleinsten Quadrate wird zusammenfassend dargestellt. Die verschiedenen Schätzverfahren, die sich aus der Anwendung dieser Methode ergeben, werden in ihren Grundzügen systematisch entwickelt. Dabei wird auf die Unterschiede der Schätzung bei statischen und dynamischen Systemen sowie auf das Problem der Erwartungstreue besonders eingegangen.