bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Term Outcomes in Anterior Cruciate Ligament Reconstruction: A Systematic Review of Patellar Tendon Versus Hamstring Autografts
Authors: Poehling-Monaghan Kirsten L. , Salem Hytham , Ross Kirsten E. , Secrist Eric , Ciccotti Michael C. , Tjoumakaris Fotios , Ciccotti Michael G. , Freedman Kevin B.
Published: June 2017

Background:

Much controversy still exists surrounding graft choice in anterior cruciate ligament (ACL) reconstruction. Over the past decade, an increase in comparative studies with longer follow-up has enhanced our understanding of current graft options and outcomes.

Purpose:

To describe the long-term comparative outcomes of ACL reconstruction with autograft bone–patellar tendon–bone (BPTB) versus autograft hamstring (HS) ACL reconstruction with regard to clinical and radiographic outcomes.

Study Design:

Systematic review; Level of evidence, 2.

Methods:

A search of the PubMed, MEDLINE, Cochrane, and Scopus databases was performed to identify studies in the English language with outcome data comparing ACL reconstruction utilizing autograft BPTB and autograft HS; only studies with a minimum 5-year follow-up were included. Outcome data included failure and complications, manual and instrumented laxity, patient-reported outcomes, and radiographic risk of osteoarthritis.

Results:

Twelve studies with a total of 953 patients met the inclusion criteria. Of these studies, 8 were level 1 evidence and 2 were level 2. Mean follow-up was 8.96 years (range, 5-15.3 years). No differences in graft failure or manual or instrumented laxity were seen in any studies. Lower clinical outcomes scores and greater motion loss were seen in BPTB patients in 1 and 2 studies, respectively. Two of 4 studies reporting on anterior knee pain, and 3 of 7 that recorded kneeling pain found it more frequently among BPTB patients. One study found significantly increased reoperation rates in HS patients, while another found a similar result in BPTB, and 1 study reported a significant increase in contralateral ACL tears in BPTB patients. Three of 5 studies reporting on radiographic evidence of osteoarthritis noted significantly increased rates in BPTB patients.

Conclusion:

This systematic review comparing long-term outcomes after ACL reconstruction with either autograft BPTB or autograft HS suggests no significant differences in manual/instrumented laxity and graft failures between graft types. An increase in long-term anterior knee pain, kneeling pain, and higher rates of osteoarthritis were noted with BPTB graft use.
Family Support of Third-Grade Reading Skills, Motivation, and Habits
Authors: Capotosto Lauren , Kim James S. , Burkhauser Mary A. , Oh Park Soojin , Mulimbi Bethany , Donaldson Maleka , Kingston Helen Chen
Published: June 2017

This qualitative study investigated the ways in which 84 parents from predominantly low-income communities described supporting their third graders’ reading skills, motivation, and habits. Thematic analysis of open-ended parent interviews indicated that parents actively and deliberately scaffolded their children’s progress toward developing independent reading skills. Parents explicitly communicated the value of reading in everyday conversations; actively listened to their children read, even if they did not understand the language in which the text was written; asked reading comprehension questions; created a home environment conducive to sustained reading; promoted reader autonomy through encouragement of strategy use; and incorporated reading practices into daily routines. Parents often described their own efforts as responsive to their children’s level of reading motivation and reading performance, thus highlighting the reciprocal nature of parent–child reading interactions. Findings reveal a variety of ways in which families support their children’s reading skills, motivation, and habits.
Uncovering Factors Influencing Interpersonal Health Communication
Authors: Donné Lennie , Jansen Carel , Hoeks John
Published: June 2017

Talking to friends, family, or peers about health issues might, among other things, increase knowledge of social norms and feelings of self-efficacy in adopting a healthier lifestyle. We often see interpersonal health communication as an important mediating factor in the effects of health campaigns on health behavior. No research has been done so far, however, on factors that influence whether and how people talk about health issues without being exposed to a health campaign first. In this exploratory study, we interviewed 12 participants about their communication behavior concerning six different health themes, like smoking and exercising. The results suggest that at least four types of interpersonal health communication can be distinguished, each influenced by different factors, like conversational partner and objective of the conversation. Future research should take this diversity of interpersonal health communication into account, and focus on designing health campaigns that aim to trigger dialogue within target populations.
Daratumumab yields rapid and deep hematologic responses in patients with heavily pretreated AL amyloidosis
Authors: Kaufman Gregory P. , Schrier Stanley L. , Lafayette Richard A. , Arai Sally , Witteles Ronald M. , Liedtke Michaela
Published: June 2017

Key Points

Daratumumab is highly active in AL amyloidosis.
Osteonecrosis in children and adolescents with acute lymphoblastic leukemia: a therapeutic challenge
Authors: Kuhlen Michaela , Kunstreich Marina , Krull Kathinka , Meisel Roland , Borkhardt Arndt
Published: June 2017

Osteonecrosis (ON) represents one of the most common and debilitating sequelae of antileukemic treatment in children and adolescents with acute lymphoblastic leukemia (ALL). Systematic screening strategies can focus on early detection and intervention to prevent ON from progressing to stages associated with pain and functional impairment. These strategies hold promise for reducing ON-associated morbidity without the risk of impairing leukemia control. Herein, we critically reviewed clinical data on pharmacological, nonpharmacological/nonsurgical, and surgical (including cellular) treatment options for ON, which are covered in the literature and/or are conceivable based on the supposed underlying ON pathophysiology. Prevention of ON progression is of paramount importance, and attempts seem to be more effective in early (precollapse) disease status than in late-stage (collapse) ON. Based on the results of ongoing prospective magnetic resonance imaging screening studies, which will hopefully identify those patients with a high risk of ON progression and debilitating sequelae, prospective interventional studies are urgently needed. Although there is still a lack of high-quality studies, based on currently available data, core decompression surgery combined with cellular therapies (eg, employing mesenchymal stem cells) appears most promising for preventing joint infraction in children at high risk of developing late-stage ON.
An open-source full 3D electromagnetic modeler for 1D VTI media in Python: empymod
Authors: Werthmüller Dieter
Published: June 2017

The Python-code empymod computes the 3D electromagnetic field in a layered earth with vertical transverse isotropy by combining and extending two earlier presented algorithms in this journal. The bottleneck in frequency- and time-domain calculations of electromagnetic responses derived in the wavenumber-frequency domain is the transformations from the wavenumber to the space domain and from the frequency to the time domain, the so-called Hankel and Fourier transforms. Three different Hankel transform methods (quadrature, quadrature-with-extrapolation [QWE], and filters) and four different Fourier transform methods (fast Fourier transform [FFT], FFTLog, QWE, and filters) are included in empymod, which allows us to compare these different methods in terms of speed and precision. The best transform in terms of speed and precision depends on the modeled frequencies. Published digital filters for the Hankel transform are very fast and precise for frequencies in the range of controlled-source electromagnetic data, but they fail in the frequency range of ground-penetrating radar. Conventional quadrature, on the other hand, is in comparison very slow but can model any frequency. Examples comparing empymod with analytical solutions and with existing electromagnetic modelers illustrate the capabilities of empymod.
The Effect of Chronic Opioid Use on End-Tidal Concentration of Sevoflurane Necessary to Maintain a Bispectral Index Below 50: A Prospective, Single-Blind Study
Authors: Oh Tak Kyu , Eom Woosik , Yim Jiyeon , Kim Namwoo , Kwon Kyungho , Kim Seong-Eun , Kim Dae Hyun
Published: June 2017

BACKGROUND:

Opioid analgesics decrease the minimum alveolar concentration of inhalation agents during the acute phase response. However, the effect of chronic opioid exposure on minimum alveolar concentration of inhalation agents remains unknown. This study aimed to determine the concentration of sevoflurane necessary to maintain a bispectral index (BIS) <50 (SEVOBIS50) in patients with chronic opioid use compared with those naïve to opioid use.

METHODS:

We included chronic opioid users who received a stable dose of oral morphine of at least 60 mg/d according to the morphine equivalent daily dose for at least 4 weeks and opioid-naïve patients. General anesthesia that included thiopental, vecuronium, and sevoflurane in oxygen was administered to all patients. Anesthesia was maintained using predetermined end-tidal sevoflurane concentrations. Fifteen minutes after achieving the determined end-tidal sevoflurane concentration through closed circuit anesthesia, BIS was measured for 1 minute in both groups. SEVOBIS50 was determined using Dixon‘s up–down method and probit analysis.

RESULTS:

Nineteen and 18 patients from the chronic opioid and control groups, respectively, were included in the final analysis. SEVOBIS50values for the chronic opioid and control patients were 0.84 (95% confidence interval, 0.58–1.11) and 1.18 (95% confidence interval, 0.96–1.40), respectively (P = .0346).

CONCLUSIONS:

Our results suggest that the end-tidal concentration of sevoflurane necessary to maintain a BIS <50 is lower for chronic opioid users than for opioid-naïve patients.
Development and Validation of a Risk Scale for Emergence Agitation After General Anesthesia in Children: A Prospective Observational Study
Authors: Hino Maai , Mihara Takahiro , Miyazaki Saeko , Hijikata Toshiyuki , Miwa Takaaki , Goto Takahisa , Ka Koui
Published: June 2017

BACKGROUND:

Emergence agitation (EA) is a common complication in children after general anesthesia. The goal of this 2-phase study was (1) to develop a predictive model (EA risk scale) for the incidence of EA in children receiving sevoflurane anesthesia by performing a retrospective analysis of data from our previous study (phase 1) and (2) to determine the validity of the EA risk scale in a prospective observational cohort study (phase 2).

METHODS:

Using data collected from 120 patients in our previous study, logistic regression analysis was used to predict the incidence of EA in phase 1. The optimal combination of the predictors was determined by a stepwise selection procedure using Akaike information criterion. The β-coefficient for the selected predictors was calculated, and scores for predictors determined. The predictive ability of the EA risk scale was assessed by a receiver operating characteristic (ROC) curve, and the area under the ROC curve (c-index) was calculated with a 95% confidence interval (CI). In phase 2, the validity of the EA risk scale was confirmed using another data set of 100 patients (who underwent minor surgery under general anesthesia). The ROC curve, the c-index, the best cutoff point, and the sensitivity and specificity at the point were calculated. In addition, we calculated the gray zone, which ranges between the two points where sensitivity and specificity, respectively, become 90%.

RESULTS:

In phase 1, the final model of the multivariable logistic regression analysis included the following 4 predictors: age (logarithm odds ratios [OR], −0.38; 95% CI, −0.81 to 0.00), Pediatric Anesthesia Behavior score (logarithm OR, 0.65; 95% CI, −0.09 to 1.40), anesthesia time (logarithm OR, 0.60; 95% CI, −0.18 to 1.19), and operative procedure (logarithm OR, 2.53; 95% CI, 1.30–3.75 for strabismus surgery and logarithm OR, 2.71; 95% CI, 0.99–4.45 for tonsillectomy). The EA risk scale included these 4 predictors and ranged from 1 to 23 points. In phase 2, the incidence of EA was 39%. The c-index of phase 1 was 0.84 (95% CI, 0.74–0.94), and the c-index of phase 2 was 0.81 (95% CI, 0.72–0.89). The best cutoff point for the EA risk scale was 11 (sensitivity = 87% and specificity = 61%). The gray zone ranged from 10 to 13 points, and included 38% of patients.

CONCLUSIONS:

We developed and validated an EA risk scale for children receiving sevoflurane anesthesia. In our validation cohort, this scale has excellent predictive performance (c-index > 0.8). The EA risk scale could be used to predict EA in children and adopt a preventive strategy for those at high risk. This score-based preventive approach should be studied prospectively to assess the safety and efficacy of such a strategy.
A Hospital Is Not Just a Factory, but a Complex Adaptive System—Implications for Perioperative Care
Authors: Mahajan Aman , Islam Salim D. , Schwartz Michael J. , Cannesson Maxime
Published: June 2017

Many methods used to improve hospital and perioperative services productivity and quality of care have assumed that the hospital is essentially a factory, and therefore, that industrial engineering and manufacturing-derived redesign approaches such as Six Sigma and Lean can be applied to hospitals and perioperative services just as they have been applied in factories. However, a hospital is not merely a factory but also a complex adaptive system (CAS). The hospital CAS has many subsystems, with perioperative care being an important one for which concepts of factory redesign are frequently advocated. In this article, we argue that applying only factory approaches such as lean methodologies or process standardization to complex systems such as perioperative care could account for difficulties and/or failures in improving performance in care delivery. Within perioperative services, only noncomplex/low-variance surgical episodes are amenable to manufacturing-based redesign. On the other hand, complex surgery/high-variance cases and preoperative segmentation (the process of distinguishing between normal and complex cases) can be viewed as CAS-like. These systems tend to self-organize, often resist or react unpredictably to attempts at control, and therefore require application of CAS principles to modify system behavior. We describe 2 examples of perioperative redesign to illustrate the concepts outlined above. These examples present complementary and contrasting cases from 2 leading delivery systems. The Mayo Clinic example illustrates the application of manufacturing-based redesign principles to a factory-like (high-volume, low-risk, and mature practice) clinical program, while the Kaiser Permanente example illustrates the application of both manufacturing-based and self-organization–based approaches to programs and processes that are not factory-like but CAS-like. In this article, we describe how factory-like processes and CAS can coexist within a hospital and how self-organization–based approaches can be used to improve care delivery in many situations where manufacturing-based approaches may not be appropriate.
Ovarian fluid impacts flagellar beating and biomechanical metrics of sperm between alternative reproductive tactics
Authors: Butts Ian A. E. , Prokopchuk Galina , Kašpar Vojtěch , Cosson Jacky , Pitcher Trevor E.
Published: June 2017

Alternative reproductive tactics (ARTs) are prevalent in nature, where smaller parasitic males typically have better sperm quality than larger territorial guard males. At present, it is unclear what is causing this phenomenon. Our objective was to gain insights into sperm form and function by examining flagellar beating patterns (beat frequency, wave amplitude, bend length, bend angle, wave velocity) and biomechanical sperm metrics (velocity, hydrodynamic power output, propulsive efficiency) of wild spawning Chinook salmon ARTs. Ovarian fluid and milt were collected to form a series of eight experimental blocks, each composed of ovarian fluid from a unique female and sperm from a unique pair of parasitic jack and guard hooknose males. Sperm from each ART were activated in river water and ovarian fluid. Flagellar parameters were evaluated from recordings using high-speed video microscopy and biomechanical metrics were quantified. We show that ART has an impact on flagellar beating, where jacks had a higher bend length and bend angle than hooknoses. Activation media also impacted the pattern of flagellar parameters, such that beat frequency, wave velocity and bend angle declined, while wave amplitude of flagella increased when ovarian fluid was incorporated into activation media. Furthermore, we found that sperm from jacks swam faster than those from hooknoses and required less hydrodynamic power output to propel themselves in river water and ovarian fluid. Jack sperm were also more efficient at swimming than hooknose sperm, and propulsive efficiency increased when cells were activated in ovarian fluid. The results demonstrate that sperm biomechanics may be driving divergence in competitive reproductive success between ARTs.
Offline Assortment Optimization in the Presence of an Online Channel
Authors: Dzyabura Daria , Jagabathula Srikanth
Published: June 2017

Firms are increasingly selling through both offline and online channels, allowing customers to experience the touch and feel of product attributes before purchasing those products. Consequently, the selection of products offered offline affects the demand in both channels. We address how firms should select an optimal offline assortment to maximize profits across both channels; we call this the showcase decision problem. We incorporate the impact of physical evaluation on preferences into the consumer demand model. Under this model, we show that the decision problem is NP-hard. Analytically, we derive optimal results for special cases and near-optimal approximations for general cases. Empirically, we use conjoint analysis to identify changes in consumer preferences resulting from physically evaluating products. For this application, we demonstrate gains in expected revenue of up to 40% due to accounting for the impact of offline assortment on the online sales.

The online appendix is available at https://doi.org/10.1287/mnsc.2016.2708

This paper was accepted by Vishal Gaur, operations management.
Effects of System Parameters on the Optimal Cost and Policy in a Class of Multidimensional Queueing Control Problems
Authors: Vercraene Samuel , Gayon Jean-Philippe , Karaesmen Fikri
Published: June 2017

We consider a class of Markov Decision Processes frequently employed to model queueing and inventory control problems. For these problems, we explore how changes in different system input parameters (transition rates, costs, discount rates etc.) affect the optimal cost and the optimal policy when the state space of the problem is multidimensional. To address a large class of problems, we introduce two generic dynamic programming operators to model different types of controlled events. For these operators, we derive sufficient conditions to propagate monotonicity and supermodularity properties of the value function. These properties allow to predict how changes in system input parameters affect the optimal cost and policy. Finally, we explore the case when several parameters are changed at the same time.

The online appendix is available at https://doi.org/10.1287/opre.2017.1600 .
The aetiology of infections: The significance for hospital management
Authors: Roberts Luke , Cheung Ronny
Published: June 2017

Background:

Skin and soft tissue infections are among the most prevalent infections requiring medical intervention, with abscesses being a clinically important subset. Identification of a causative organism is useful for clinical decision-making and tailoring infection management. The extent to which causative agents are reflected in clinical coding data has been grossly understudied, despite its importance for statistical and financial purposes.

Methods:

An audit of admissions to a London hospital, between 1 September 2014 and 31 August 2016, was performed. Analysis was undertaken to identify whether the discharge documentation, clinical coding reports and microbiological results showed concordance in the detailing of causative organisms associated with abscesses. The impact of incongruity on hospital management was reviewed.

Results:

Of 664 admissions, 309 (46.5%) did not have a microbial swab taken at the site of the abscess. 164 (24.7%) of the admissions had positive results for one or more causative agents. Of these cases, 135 (82.3%) did not have the determined agents captured in the clinical coding reports. Capturing absent agents in the coding reports resulted in 120 Healthcare Resource Group (HRG) changes. Amendments culminated in a 77.1% uplift in total financial reimbursement of £104 190.

Conclusion:

Causative agents were not consistently recorded in the coding reports for admissions requiring abscess management. Omission carries negative implications for epidemiology, public health planning and financial reimbursement.
Brain tumours: Reducing delay in diagnosis
Authors: Newton Polly
Published: June 2017

Polly Newton explains why reducing delay in brain tumour diagnosis in children and young people is crucial and shares some of the most common signs and symptoms.
Improving outcomes in acute aortic dissection
Authors: Redfern Emma , Callaway Mark , Zakkar Mustafa , Bryan Alan J
Published: June 2017

Aortic dissection remains a serious cardiovascular emergency with significant early and late mortality and morbidity. Improving outcomes is directly linked to early clinical diagnosis, swift confirmation by appropriate imaging and management by dedicated teams with high levels of expertise in a complex clinical condition.
Improving infection control standards
Authors: Taylor Kate
Published: June 2017

Appropriate infection control is integral to the health and safety of patients, practitioners and staff in general practice. With the right systems, processes and training, the risk of infection can be detected and managed, says Kate Taylor
Lei de acesso à Informação e Controle Social: Um estudo do nível de Transparência Passiva do Estado de Pernambuco
Authors: Silva Leilson Vanderson Barbosa da , Correia José Jonas Alves , Galvão Nadielli Maria Dos Santos , Monte Marciel José Do , Santos Aldemar De Araújo
Published: June 2017

Este estudo investigou o nível de transparência passiva dos órgãos do Poder Executivo do Estado de Pernambuco, através da divulgação das informações exigidas pela Lei de Acesso à Informação, nos portais de transparência do Estado. A pesquisa foi realizada por meio do portal da transparência e do site da LAI, do Estado de Pernambuco, tendo como período os anos de 2013, 2014 e 2015. Fizeram parte da amostra da pesquisa 62 entidades, entre fundações, autarquias, sociedades de economia mista e empresas públicas. Sendo assim, conclui-se que, as entidades que compõem o poder executivo do Estado de Pernambuco, deixam a desejar quando se fala do atendimento total à legislação de acesso à informação estadual. Todavia, vale ressaltar que a maior parte dos órgãos, no que diz respeito à transparência ativa, atingiram pontuação entre os níveis ‘razoável’ e ‘muito bom’, o que não torna o nível de transparência ativa tão ruim.
Habits- A contemporary review
Authors: D R Deepak , Shankar Manu , B Nair Karthika
Published: June 2017

Although oral habits are being dealt by dentist especially by Pedodontist and orthodontist since long time, but till today this particular ab-normal/normal entity is not fully known. Time-to-Time various hypothesis & explanations have been given by various authors but none of it specifically delineate the habits those which are normal for a particular age group and others, which are deleterious to stomatognathic sys-tem. The main reason for this difficulty is that a habit may be a part of normal development, a symptom associated with deep-rooted Psycho-logical disturbance or a habit may be a result of abnormal facial growth. Though it is difficult to delineate it, but it is important to have dif-ferentiation of abnormal from normal because If normal development get disturbed unknowingly and at the same time If abnormal growth or underlying psychological cause let continue without interfering at proper time/age it will lead to long lasting effect on stomatognathic system its growth & development and psychological development of child.
Melhoria de processos na gestão pública: uma pesquisa-ação com foco nas atividades administrativas de um programa de intercâmbio estudantil de uma universidade pública
Authors: Barbalho Sanderson César Macêdo , Nitzsche Maria Cristina Mozaner , Dantas Ananda Silveira
Published: June 2017

O presente artigo apresenta o estudo e proposição de melhorias dos processos administrativos de um programa de mobilidade estudantil em uma Instituição Federal de Ensino Superior. Foi realizada uma pesquisa-ação através do mapeamento dos processos utilizando fluxograma de processo e foram identificados pontos de melhoria baseados em conceitos de produção enxuta. Os procedimentos metodológicos utilizados foram análise de documentos pertencentes ao Programa e análise do histórico dos documentos e ações desenvolvidos no setor por ele responsável. É realizado o desenho e descrição do macroprocesso. Posteriormente foi realizada análise dos desperdícios do processo atual e são propostas ações de melhoria com base em mapas de estado futuro. Propôs-se eliminar atividades que geravam desperdício e que não agregavam valor. Tais propostas foram validadas com os gestores do Programa e algumas iniciativas foram implementadas. Melhorias da ordem de 74% no fluxo de informações e 44% nos tempos de processamento foram conseguidas.
Utilização da análise envoltória de dados (DEA) na composição de carteira de investimento diversificada e eficiente
Authors: Alexandrino Fernando Queiroz de Lira , Santos Renan André Barbosa dos , Angulo-Meza Lidia , Bordeaux-Rego Ricardo
Published: June 2017

Diante de diversos tipos de aplicações financeiras, o investidor pode ter dificuldade em qual opção escolher, diante das variações da relação retorno x risco apresentadas por cada modalidade. Especialmente no caso das ações, ativos considerados de alto risco, a composição de um portfólio diversificado possibilita que o investidor tenha maiores chances de obter boa rentabilidade, assim como redução considerável do risco do investimento. Este estudo objetiva empregar a Análise Envoltória de Dados (DEA) para compor uma carteira eficiente, sob a ótica de indicadores comumente utilizados em análises fundamentalistas. A metodologia consistiu em coleta de dados junto à bolsa de valores e demais fontes de investimento, seleção das ações eficientes e otimização da carteira resultante, usando para isto o modelo de Markowitz. Os resultados indicaram que, dos cem títulos com maior volume de negociação, apenas dez foram considerados eficientes, e a carteira formada por eles obteve desempenho superior aos dos índices Ibovespa e IBr-X100. Foi possível concluir que a diversificação de portfólio de ações é uma opção viável e satisfatória em relação aos demais tipos de investimentos disponíveis para o investidor, possibilitando assim que o mesmo tenha condições de escolher uma carteira de investimento eficiente e otimizar a relação retorno x risco.
Estudo comparativo entre os métodos gradiente reduzido generalizado e algoritmo genético em otimização com múltiplas respostas
Authors: Gomes Fabrício Maciel , Pereira Félix Monteiro , Marins Fernando Augusto Silva , Silva Messias Borges
Published: June 2017

Neste trabalho foi realizado um estudo comparativo entre as metodologias de otimização Gradiente Reduzido Generalizado (GRG) e Algoritmo Genético (AG) para a otimização de processos com múltiplas respostas. Para estimar os parâmetros que minimizam a função objetivo foram utilizadas respostas geradas por planejamento de experimentos de forma aglutinada, as quais foram incorporadas à função objetivo. Os estudos de caso utilizados foram baseados em trabalhos selecionados na literatura e, para cada experimento selecionado, foi realizada a otimização dos valores dos parâmetros do processo utilizando as duas metodologias, o GRG, por meio de uma planilha do Microsoft Excel e o AG utilizando o software Scilab. Foram realizadas 10 replicações e calculada a média dos resultados obtidos. A comparação entre os métodos foi realizada com base em medidas de desempenho, por meio da distância média percentual. O AG apresentou melhores resultados em comparação com o GRG.
Изучение переходных процессов в нелинейно деформируемых средах
на основе интегральных представлений и метода дискретных областей
Authors: Петушков Владимир Алексеевич , Petushkov Vladimir Alexevich
Published: June 2017

Для изучения переходных процессов в объемных нелинейно деформируемых средах разработаны методы моделирования, основанные на интегральных представлениях трехмерной краевой задачи упругой динамики, численных схемах высокого порядка аппроксимации границ и коллокационного приближения решения. Представлены обобщенные формулировки метода граничных интегральных уравнений, использующие фундаментальные решения статической упругости, уравнения состояния упругопластических сред с анизотропным упрочнением и разностные методы интегрирования по времени. Учитываются сложные истории комбинированного медленно меняющегося во времени и ударного нагружения составных кусочно-однородных сред при наличии зон локального возмущения решения. С использованием разработанного метода дискретных областей получены решения прикладных задач о распространении нелинейных волн напряжений в неоднородных средах. Приведены сравнения с решениями, полученными методом конечных элементов. Они подтверждают вычислительную эффективность разработанных алгоритмов, а также общность и полезность для практических целей предлагаемого подхода.
Получение точных аналитических решений нестационарных задач теплопроводности ортогональными методами
Authors: Кудинов Василий Александрович , Kudinov Vasilii Aleksandrovich , Клеблеев Руслан Мухтарович , Klebleev Ruslan Mukhtarovich , Куклова Екатерина Александровна , Kuklova Ekaterina Aleksandrovna
Published: June 2017

При совместном использовании ортогональных методов Л. В. Канторовича, Бубнова-Галеркина и интегрального метода теплового баланса получено точное аналитическое решение нестационарной задачи теплопроводности для бесконечной пластины при симметричных граничных условиях первого рода. Нахождение точного решения при использовании приближенных методов оказалось возможным вследствие использования тригонометрических координатных функций, обладающих свойством ортогональности. Их применение позволяет находить собственные числа не через решение краевой задачи Штурма-Лиувилля, в котором интегрированию подлежит дифференциальное уравнение второго порядка, а через решение дифференциального уравнения относительно неизвестной функций времени, являющегося уравнением первого порядка. Благодаря этому же свойству координатных функций при нахождении из начальных условий констант интегрирования удается избежать решения больших систем алгебраических линейных уравнений с плохо обусловленными матрицами коэффициентов. В связи с чем значительно упрощается как процесс получения решения, так и окончательная формула для него при возможности нахождения не только приближенного, но и точного аналитического решения в форме бесконечного ряда.
Нелинейная модель вязкоупругопластичности типа Максвелла: моделирование влияния температуры на кривые деформирования, релаксации и ползучести
Authors: Хохлов Андрей Владимирович , Khokhlov Andrew Vladimirovich
Published: June 2017

Исследуются область применимости, арсенал возможностей и способы идентификации и настройки нелинейного определяющего соотношения типа Максвелла для вязкоупругопластичных материалов с двумя произвольными материальными функциями и двумя параметрами (в случае одноосного изотермического нагружения). Оно нацелено на описание комплекса основных реологических эффектов, типичных для реономных материалов, обладающих наследственностью, высокой скоростной чувствительностью и разносопротивляемостью, для которых характерны установившаяся ползучесть, стадия течения при постоянном напряжении и возрастание податливости, скоростей диссипации, релаксации, ползучести и рэтчетинга и скоростной чувствительности с увеличением температуры. К ним относятся, в частности, многие полимеры, их расплавы и растворы, композиты, твердые топлива, асфальтобетоны, титановые и алюминиевые сплавы, углеродные и керамические материалы при высоких температурах и др.
Для учета влияния температуры на механическое поведение материалов (при изотермических процессах) два материальных параметра модели (коэффициент вязкости и «модуль упругости») рассматриваются как функции температуры. Найдены ограничения на свойства этих функций, необходимые и достаточные для адекватного описания качественных характеристик влияния температуры на экспериментальные кривые ползучести, релаксации, деформирования с постоянными скоростями, ползучести при ступенчатом нагружении, на касательный модуль и предел текучести, скоростную чувствительность и скорость накопления пластической деформации, типичных для стабильных вязкоупругопластичных материалов в изотермических квазистатических испытаниях. Они получены в результате аналитического изучения свойств кривых релаксации, ползучести и деформирования, порождаемых определяющим соотношением типа Максвелла с произвольными материальными функциями, и их сопоставления с типичными свойствами экспериментальных кривых реономных материалов. Доказано, что коэффициент вязкости, «модуль упругости» и их отношение (время релаксации ассоциированной линейной модели Максвелла) должны быть убывающими функциями температуры, и это обеспечивает адекватное качественное описание десятка наблюдаемых базовых термомеханических эффектов, свидетельствующих о возрастании податливости материалов (в частности, убывании касательного модуля и предела текучести), скоростей релаксации, ползучести и рэтчетинга и скоростной чувствительности с ростом температуры.
Крупномасштабная слоистая стационарная конвекция вязкой несжимаемой жидкости
под действием касательных напряжений на верхней границе. Исследование поля скоростей
Authors: Бурмашева Наталья Владимировна , Burmasheva Natal'ya Vladimirovna , Просвиряков Евгений Юрьевич , Prosviryakov Eugenii Yurevich
Published: June 2017

Рассматривается точное решение задачи об определении конвективных движений в слоистых крупномасштабных течениях вязкой несжимаемой жидкости в стационарном случае. Показано, что получаемая задача является, во-первых, переопределенной и, во-вторых, нелинейной (за счет наличия членов конвективной производной в уравнении теплопроводности). Также показано, что выбором класса решений систему можно избавить от переопределенности, а уточнением ряда краевых условий свести задачу к задаче исследования термокапиллярной конвекции (конвекции Бенара-Марангони). Далее определяются условия появления противотечений. Исследуется их возможное количество. Кроме того, проводится анализ исследуемого течения на предмет наличия безвихревых областей. Показано, что при некоторых сочетаниях параметров системы возможны смены направления вихря.
Оценка порядка аппроксимации матричного метода численного интегрирования краевых
задач для систем линейных неоднородных обыкновенных дифференциальных уравнений
второго порядка с переменными коэффициентами.
Сообщение 2. Краевые задачи с граничными условиями второго и третьего рода
Authors: Маклаков Владимир Николаевич , Maklakov Vladimir Nikolaevich
Published: June 2017

Представлено второе сообщение цикла из двух статей, в котором исследованы закономерности изменения порядка аппроксимации матричного метода численного интегрирования в зависимости от используемой степени в разложении в многочлен Тейлора решений краевых задач для систем обыкновенных дифференциальных уравнений второго порядка с переменными коэффициентами с граничными условиями второго и третьего рода.
Использование многочлена Тейлора второй степени при аппроксимации производных конечными разностями приводит ко второму порядку аппроксимации традиционного метода сеток во внутренних точках области интегрирования.
В работе при исследовании краевых задач для систем обыкновенных дифференциальных уравнений второго порядка рассмотрен предложенный ранее метод численного интегрирования, использующий средства матричного исчисления, в котором аппроксимация производных конечными разностями не производилась.
Согласно указанному методу при составлении системы разностных уравнений степень многочлена Тейлора может быть выбрана произвольно.
Вычислена невязка и дана оценка порядка аппроксимации метода в зависимости от выбранной степени многочлена Тейлора. Теоретически установлено следующее:
a) для краевых задач с граничными условиями второго и третьего рода
порядок аппроксимации пропорционален используемой степени многочлена Тейлора и меньше этой степени, независимо от ее четности, на единицу;
б) при четной степени порядок аппроксимации в граничных точках области интегрирования на единицу меньше порядка аппроксимации во внутренних точках;
в) при нечетной степени порядки аппроксимации в граничных точках и во внутренних точках области интегрирования совпадают и меньше этой степени на единицу.
Для четной степени дан метод повышения порядка аппроксимации на единицу в граничных точках области интегрирования до порядка аппроксимации во внутренних точках.
Теоретические выводы подтверждены численным экспериментом для краевых задач с граничными условиями третьего рода.
Green Synthesis, Printing Performance, and Antibacterial Activity of Disperse Dyes Incorporating Arylazopyrazolopyrimidines
Authors: Khattab Tawfik A. , Elnagdi Mohamed H. , Haggaga Karima M. , Abdelrahmana Amal A. , Aly Sherif Abdelmoez
Published: June 2017

Novel heterocyclic arylazo-disperse dyes containing pyrazolo[1,5-a]pyrimidine structures were prepared via conventional refluxing and microwave heating. Starting from cyanoacetic acid, 4-arylazo-2H-pyrazol-3-ylamine was obtained from a sequence of reactions. This pyrazole intermediate afforded the target arylazo-pyrazolo[1,5-a]pyrimidines and pyrazolo[1,5-a] pyrimidin-7-ones upon cyclization with 3-piperidinylacrylonitrile, ethyl acetoacetate, ethyl(arylhydrazono)acetoacetates, or (arylhydrazono)propanals. The structures of these compounds were confirmed by 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy, infrared (IR) analysis, and elemental analysis. The disperse colorants produced were applied to printing on polyester fabrics to give satisfactory results. All the synthesized products were tested as antimicrobial agents. Most compounds exhibited relatively strong antibacterial activity against a panel of Gram-positive and Gram-negative bacteria.
Examination of academic self-efficacy and motivation according to demographic characteristics of graduate education candidates (Cumhuriyet University example)
Lisansüstü eğitim adaylarının akademik öz-yeterlik ve güdülenmelerinin demografik özelliklerine göre incelenmesi (Cumhuriyet Üniversitesi örneği)
Authors: Özgül Fatih , Diker Gürkan
Published: June 2017

The aim of this research is to examine the academic self-efficacy and motivation of candidates applying for the postgraduate education program of the Institute of Health Sciences according to the age, sex, graduated section and marital status variables. The sample of this research in the relational screening model is composed of 100 students who applied to the Physical Education and Sports Master program, which is included in the study by using appropriate sampling method. Academic Self-efficacy Scale and Academic Motivation Scale was applied to the candidates in the study. In evaluating the data; The error level was taken as .05 using Variance Analysis, Tukey test, Difference between Two Means Significance Test and Correlation Analysis. As a result, it has been found that candidates' academic self-efficacy and academic motivation scores differ significantly from their age and graduation levels.Extended English abstract is in the end of PDF (TURKISH) file. ÖzetBu araştırmanın amacı sağlık bilimleri enstitüsü lisansüstü eğitim programına başvuru yapan adaylarının akademik öz-yeterlik ve güdülenmelerinin yaş, cinsiyet, mezun olunan bölüm ve medeni durum değişkenlerine göre incelenmesidir. İlişkisel tarama modelinde olan bu araştırmanın örneklemini uygun örnekleme yöntemi kullanılarak araştırmaya dahil edilen Beden Eğitimi ve Spor Yüksek Lisans programına başvuru yapan 100 öğrenci oluşturmaktadır. Araştırmada adaylara, Akademik Öz-yeterlik Ölçeği ile Akademik Güdülenme Ölçeği uygulanmıştır.Verilerin değerlendirilmesinde; Varyans Analizi, Tukey testi, İki Ortalama Arasındaki Farkın Önemlilik Testi ve Korelasyon Analizi kullanılarak yanılma düzeyi  .05 olarak alınmıştır. Sonuç olarak adayların akademik öz-yeterlik ve akademik güdülenme puanlarının yaşa ve mezun oldukları bölümlere göre anlamlı ölçüde farklılaştığı tespit edilmiştir.
Experimental and theoretical approach to exploit the corrosion inhibition activity of 3-formyl chromone derivatives on mild steel in 1 m H2SO4
Authors: Kumar Rajeev , Chahal Savita , Dahiya Shefali , Dahiya Naveen , Kumar Sumit , Lata Suman
Published: June 2017

3-Formyl chromone (3FC) derivatives, viz. 5-methoxy-3FC (5-Me-3FC), 6-hydroxy-3FC (6-OH-3FC), and 7-hydroxy-3FC (7-OH-3FC), were studied for the inhibition of mild steel corrosion in 1 m H2SO4 at different temperatures and concentrations. The inhibition was studied using mass loss method, polarization technique, electrochemical impedance spectroscopy (EIS), scanning electron microscopy, and quantum chemical calculations. The results from mass loss, potentiodynamic polarization, and EIS showed that inhibition efficiency (IE) increased with gradual increments in concentration of 3FC derivatives. The polarization study revealed that these compounds act as mixed-type inhibitors and Langmuir adsorption isotherm is fitted well for adsorption behavior. The order of IE provided by all the three compounds is 7-OH-3FC≈6-OH-3FC>5-Me-3FC and lies in the range of 85%–95%. A proposed inhibition mechanism has been further described, including the support from all the experimental and theoretical techniques.
Artisans, Retailers, and Credit Transactions in the Roman World
Authors: Hawkins Cameron
Published: June 2017

In this article, I argue not just that many artisans and retailers in the Roman world were able to finance their businesses only by relying heavily on access to credit, but also that they depended primarily upon trade credit—that is, upon interpersonal credit provided to them by suppliers and subcontractors to whom they were linked by relationships of trust, and from whom they purchased goods and services on account. This was true primarily because most artisans and retailers catered to clients who often lacked ready money when they made purchases, and thus found it necessary to offer shop credit instead of concluding sales in exchange for immediate cash payments. This strategy in turn exacerbated their own cash flow problems and compelled them to incur liabilities that could easily match or exceed the value of their tangible assets. In these circumstances, many found that trade credit was both more accessible than loans procured on the credit market (for which they often lacked the necessary collateral), and also less risky, since suppliers of trade credit could be more forgiving of missed payments than conventional lenders (who were likely to take actions that could result either in seizure of an entrepreneur’s collateral or in his or her insolvency).
The Inception of the Seleukid Empire
Authors: Vădan Paul
Published: June 2017

The paper looks at the fragmentary cuneiform evidence from the initial years of Seleukos’ rule at Babylon, to explain how Macedonian authority was imposed in Mesopotamia after Alexander the Great’s death. Beyond military might and sheer opportunism, the consolidation of Seleukos’ rule in Babylon was achieved through careful negotiations of privileges and guarantees with the local temple elites. This relationship of mutual recognition was reinforced through the composition and propagation of prophetic Babylonian accounts. These were meant to interpret a period of dynastic crisis as the cosmic unfolding of a divine plan, manifested through the decisive success of Seleukos.
Detecting capital market convergence clubs
Authors: Beylunioglu Fuat C. , Stengos Thanasis , Yazgan M. Ege
Published: June 2017

In this study, we propose a new method to find convergence clubs that combine pairwise method of testing convergence with maximal clique algorithm. Unlike many of those already developed in the literature, this new method aims to find convergence clubs endogenously without depending on priori classifications. We use our method to study convergence among different capital markets as captured by their respective indices. Stock market convergence would indicate the absence of arbitrage opportunities in moving between the different markets as they would all present investors with similar risks. Furthermore, stock market convergence would be a precursor to GDP convergence as these economies would be bound by similar (possibly unobservable) common factors that affect long run macroeconomic performance.
El huerto escolar como herramienta innovadora que contribuye al desarrollo competencial del estudiante universitario. Una propuesta educativa multidisciplinar/The school garden as an innovative tool that contributes to the skills development of the colleg
Authors: Botella Nicolás Ana Maria , Hurtado Soler Amparo , Cantó Doménech José
Published: June 2017

El huerto escolar es un recurso pedagógico que permite aproximar al alumnado al entorno natural diseñando experiencias interdisciplinares que contribuyan al desarrollo de las competencias básicas. En el ámbito universitario facilita el aprendizaje cooperativo y la adquisición de habilidades socioambientales. El proyecto L’Hort 2.0 pretende crear un entorno virtual basado en el huerto escolar para la administración de contenidos TIC que permitan enlazar las actividades fuera del aula con el contenido de las guías docentes. Se trabaja mediante una metodología activa y colaborativa, en tres fases: preparación y diseño del entorno web en seis áreas temáticas; elaboración de materiales educativos y evaluación de su utilidad en el aula y su eficacia en el proceso de aprendizaje del alumnado. Los resultados obtenidos muestran una elevada implicación del alumnado en el proceso formativo y una mejora en los resultados de evaluación que permite integrar todas las capacidades del alumnado reflejando mejor las competencias alcanzadas.
La publicidad y su responsabilidad social / Advertising and its social responsibility
Authors: Pellicer Jordá María Teresa
Published: June 2017

El poder de la publicidad es cada vez mayor en una sociedad donde el consumo es ya una costumbre. Su poder radica, no sólo en su capacidad persuasiva, sino también en su amplia presencia en la vida de los ciudadanos, que visionan cada día cientos de anuncios, aunque no siempre sean conscientes de ello. Por eso, por una innegable influencia en la sociedad, la publicidad debe trabajar en el desarrollo de su responsabilidad social. Sobre este tema, ofreciendo argumentos de diversos autores, reflexionamos en este artículo.