254 research outputs found
Extraversion and Reward-Processing: Consolidating Evidence from an Electroencephalographic Index of Reward-Prediction-Error
Trait extraversion has been theorized to emerge from functioning of the dopaminergic reward system. Recent evidence for this view shows that extraversion modulates the scalp-recorded Reward Positivity, a putative marker of dopaminergic signaling of reward-prediction-error. We attempt to replicate this association amid several improvements on previous studies in this area, including an adequately-powered sample (N = 100) and thorough examination of convergent-divergent validity. Participants completed a passive associative learning task presenting rewards and non-rewards that were either predictable or unexpected. Frequentist and Bayesian analyses confirmed that the scalp recorded Reward Positivity (i.e. the Feedback-Related-Negativity contrasting unpredicted rewards and unpredicted non-rewards) was significantly associated with three measures of extraversion and unrelated to other basic traits from the Big Five personality model. Narrower sub-traits of extraversion showed similar, though weaker associations with the Reward Positivity. These findings consolidate previous evidence linking extraversion with a putative marker of dopaminergic reward-processing
Physical and mathematical modelling of the conditions of coal and gas outbursts
Purpose. Experimental study and theoretical modeling of conditions initiating destructive processes and development of gas generation in coals.
Methods. Analysis, generalization and statistical processing of experimental data and results of analytical studies followed by the identification of patterns, and numerical solution of equations in partial derivatives.
Findings. Experimental studies of changes in properties of mechanically activated samples of gas coal and fat coal in weak electric fields have been performed. The experimental results were compared with the characteristics of coals taken from the zones of different outburst hazard probability, which enabled to formulate new ideas about the causes of gas generation in coals. A mathematical model has been elaborated for gas outburst development taking into consideration the solid phase porosity changes due to the transition of coal organic mass to gas.
Originality. The treated samples with the broken microstructure demonstrated a significant increase (1.5 – 3 times) in the characteristic time of methane desorption and manifestation of electret properties identified by the value of the evoked potential and electrochemical activity, while qualitative and quantitative changes in the treated coal properties were identical to the natural analogues. It is for the first time that the developed mathematical model of gas flow during the outburst reproduces the changes in porosity and permeability of the rock caused by chemical reactions of gas generation by coal organic mass.
Practical implications. The improvement of the proposed outburst model can be used for predictive estimations of instantaneous outbursts taking into account the changes in thermodynamic and kinetic stability parameters of the “coal – gas” system.Цель. Экспериментальные исследования и теоретическое моделирование условий инициирования деструктивных и развития газогенерирующих процессов в каменных углях.
Методика. Анализ, обобщение и статистическая обработка экспериментальных показателей и результатов аналитических исследований с последующим выделением закономерностей, численное решение уравнений в частных производных.
Результаты. Выполнены экспериментальные исследования изменения свойств механоактивированных образцов угля марок Г и Ж в слабых электрических полях. Экспериментальные результаты сопоставлены с характеристиками углей, отобранных из зон с разной вероятностью выбросоопасности, на основе чего сформулированы новые представления о причинах газогенерации в углях. Разработана математическая модель развития выброса газа при изменении пористости твердой фазы вследствие перехода органической массы угля в газ.
Научная новизна. Установлено, что для обработанных образцов с нарушенной микроструктурой наблюдается значительное увеличение (в 1.5 – 3 раза) характерного времени десорбции метана и проявление электретных свойств по величине вызванного потенциала и электрохимической активности, при этом, качественные и количественные изменения свойств в обработанных углях идентичны природным аналогам. Разработанная математическая модель течения газа во время выброса впервые отражает изменения пористости и проницаемости породы, обусловленные химическими реакциями генерации газа органической массой угля.
Практическая значимость. Совершенствование предложенной модели выброса может быть использовано в прогнозных оценках внезапных выбросов с учетом изменения параметров термодинамической и кинетической устойчивости системы “уголь – газ”.Мета. Експериментальні дослідження та теоретичне моделювання умов ініціювання деструктивних і розвитку газогенеруючих процесів у кам’яному вугіллі.
Методика. Аналіз, узагальнення та статистична обробка експериментальних показників і результатів аналітичних досліджень з подальшим виділенням закономірностей, чисельне рішення рівнянь у частинних похідних.
Результати. Виконано експериментальні дослідження зміни властивостей механоактивованих зразків вугілля марок Г і Ж у слабких електричних полях. Експериментальні результати зіставлені з характеристиками вугілля, відібраних із зон з різною ймовірністю небезпеки викиду, на основі чого сформульовані нові уявлення про причини газогенерації у вугіллі. Розроблено математичну модель розвитку викиду газу при зміні пористості твердої фази внаслідок переходу органічної маси вугілля в газ.
Наукова новизна. Встановлено, що для оброблених зразків з порушеною мікроструктурою спостерігається значне збільшення (у 1.5 – 3 рази) характерного часу десорбції метану і прояв електретних властивостей за величиною викликаного потенціалу та електрохімічної активності; при цьому якісні та кількісні зміни властивостей в обробленому вугіллі ідентичні природним аналогам. Розроблена математична модель течії газу під час викиду вперше відображає зміни пористості й проникності породи, які зумовлені хімічними реакціями генерації газу органічною масою вугілля.
Практична значимість. Удосконалення запропонованої моделі викиду може бути використано у прогнозних оцінках раптових викидів з урахуванням зміни параметрів термодинамічної і кінетичної стійкості системи “вугілля – газ”.Данная работа выполнена при поддержке и финансировании Министерством образования и науки Украины проекта ГП-491 “Исследование наноструктуры ископаемых углей как источника метана угольных месторождений”. Авторы благодарят доктора технических наук Е.В. Ульянову за помощь в проведении физических исследований углей, обработанных слабыми электрическими полями
Afforestation impact on soil temperature in regional climate model simulations over Europe
In the context of the first phase of the Coordinated Regional Climate Downscaling Experiment in the European domain (EURO-CORDEX) flagship plot study on Land Use and Climate Across Scales (LUCAS), we investigate the biophysical impact of afforestation on the seasonal cycle of soil temperature over the European continent with an ensemble of 10 regional climate models. For this purpose, each ensemble member performed two idealized land cover experiments in which Europe is covered either by forests or grasslands. The multi-model mean exhibits a reduction of the annual amplitude of soil temperature (AAST) due to afforestation over all European regions, although this is not a robust feature among the models. In the Mediterranean, the spread of simulated AAST response to afforestation is between −4 and +2 ∘C at 1 m below the ground, while in Scandinavia the inter-model spread ranges from −7 to +1 ∘C. We show that the large range in the simulated AAST response is due to the representation of the summertime climate processes and is largely explained by inter-model differences in leaf area index (LAI), surface albedo, cloud fraction and soil moisture, when all combined into a multiple linear regression. The changes in these drivers essentially determine the ratio between the increased radiative energy at surface (due to lower albedo in forests) and the increased sum of turbulent heat fluxes (due to mixing-facilitating characteristics of forests), and consequently decide the changes in soil heating with afforestation in each model. Finally, we pair FLUXNET sites to compare the simulated results with observation-based evidence of the impact of forest on soil temperature. In line with models, observations indicate a summer ground cooling in forested areas compared to open lands. The vast majority of models agree with the sign of the observed reduction in AAST, although with a large variation in the magnitude of changes. Overall, we aspire to emphasize the biophysical effects of afforestation on soil temperature profile with this study, given that changes in the seasonal cycle of soil temperature potentially perturb crucial biochemical processes. Robust knowledge on biophysical impacts of afforestation on soil conditions and its feedbacks on local and regional climate is needed in support of effective land-based climate mitigation and adaption policies
Nonlinear Integer Programming
Research efforts of the past fifty years have led to a development of linear
integer programming as a mature discipline of mathematical optimization. Such a
level of maturity has not been reached when one considers nonlinear systems
subject to integrality requirements for the variables. This chapter is
dedicated to this topic.
The primary goal is a study of a simple version of general nonlinear integer
problems, where all constraints are still linear. Our focus is on the
computational complexity of the problem, which varies significantly with the
type of nonlinear objective function in combination with the underlying
combinatorial structure. Numerous boundary cases of complexity emerge, which
sometimes surprisingly lead even to polynomial time algorithms.
We also cover recent successful approaches for more general classes of
problems. Though no positive theoretical efficiency results are available, nor
are they likely to ever be available, these seem to be the currently most
successful and interesting approaches for solving practical problems.
It is our belief that the study of algorithms motivated by theoretical
considerations and those motivated by our desire to solve practical instances
should and do inform one another. So it is with this viewpoint that we present
the subject, and it is in this direction that we hope to spark further
research.Comment: 57 pages. To appear in: M. J\"unger, T. Liebling, D. Naddef, G.
Nemhauser, W. Pulleyblank, G. Reinelt, G. Rinaldi, and L. Wolsey (eds.), 50
Years of Integer Programming 1958--2008: The Early Years and State-of-the-Art
Surveys, Springer-Verlag, 2009, ISBN 354068274
Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial
IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved
Bactericidal activities of GM flax seedcake extract on pathogenic bacteria clinical strains
Methodological study to evaluate the psychometric properties of FACIT-CD in a sample of Brazilian women with cervical intraepithelial neoplasia
Background: The occurrence of cervical intraepithelial neoplasia (CIN) is associated with changes in health-related quality of life, including psychological factors, such as fear and shame, and changes in sexuality and sexual satisfaction, such as decreased sexual desire and frequency of sexual intercourse. Personal relationships are the most affected because CIN is sexually transmitted and many women tend to blame their partner for disease transmission. The aim of this study was to evaluate the psychometric properties of the FACIT-CD questionnaire in Brazilian women diagnosed with CIN.
Methods: The properties of the FACIT-CD questionnaire were tested on a sample of 439 women seen at the Department of Prevention of Barretos Cancer Hospital, including 329 patients who were diagnosed with CIN and 110 women who were not diagnosed with the disease. The analysed parameters included internal consistency (Cronbach's alpha), reproducibility (intraclass correlation coefficient), structural validity, convergent validity (correlation with the SF-12 and EORTC QLQ-CX24 questionnaires), discriminant validity (according to disease status, and self-rating of health), sensitivity, and responsiveness.
Results: The Cronbach alpha values of the FACIT-CD scales were higher than 0.70 with the exception of the relationship scale (0.66). The FACIT-CD reproducibility was satisfactory, with variation in the intraclass correlation coefficients ranging between 0.50 and 0.83, although the 95% confidence interval (CI) was lower than 0.40 (0.33-0.64) on the treatment satisfaction scale. Regarding structural validity, only one item on the physical well-being scale was not kept in the original domain. The expected correlations between the FACIT-CD and SF-12 were not confirmed, whereas the correlations between the FACIT-CD and EORTC QLQ-CX24 were confirmed. The questionnaire was able to discriminate the groups according to disease status and self-rating of health. The sensitivity was low for the relationship scale and moderate for the other scales. The responsiveness of the FACIT-CD questionnaire varied between the groups that denominate the self-perception of health as no change, improvement or worsening.
Conclusion: Our results are encouraging and indicate that the FACIT-CD questionnaire is a promising tool for the analysis of the quality of life of women with CIN.The postdoctoral fellowship was supported by Sao Paulo Research Foundation (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo - FAPESP, Sao Paulo, Brazil). Process number: FAPESP 2014/10158-3. The funding body had no role in the design of the study and collection, analysis and interpretation of data and in writing the manuscript.info:eu-repo/semantics/publishedVersio
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