3,317 research outputs found
A memory type boundary stabilization of a mildly damped wave equation
We consider the wave equation with a mild internal dissipation. It is proved that any small dissipation inside the domain is sufficient to uniformly stabilize the solution of this equation by means of a nonlinear feedback of memory type acting on a part of the boundary. This is established without any restriction on the space dimension and without geometrical conditions on the domain or its boundary
Дослідження токсикологічного впливу пива з додаванням екстракту хвої сосни
Topicality. Alcohol is one of the risk factors for many diseases, including coronary heart disease, stroke, type 2 diabetes mellitus and others. Common world ways in solving this problem in recent years has improved the preparatory technology quality of alcohol and their composition optimization, leading to lessening the negative alcohol effects on the body.Aim. To investigate the beer toxicological aspects and assess the feasibility of creating a new brewing technology with the addition of an aqueous pine needles extract, which partly replaced by hops.Material and methods. Beer prepared on the classical recipe with the addition of pine extract (600 ml/dl). The influence of beer with the pine needle extract addition on prooxidant-antioxidant status of the animals liver comparing with the beer produced by the classical recipe.Results and discussion. The animals were given the beer examples produced by classical technology at a dose of 15 g/kg for a period of 14 days significantly increased the content of oxidative markers in the liver homogenate (GC 20.4 %, TBA-reagents – 51.6 %) compared to animals that received placebo and reduced activity catalase – by 40.9 %. Biomarkers in liver homogenate of animals treated beer with an pine needles extract were within the physiological norm. Under the influence of prednisolone (50 mg/kg) dien conjugates content in the liver of animals treated with classical technologies beer by 23.8 % more than in animals that under conditions of oxidative stress used purified water. The content of TBA-reagents over 13.7 %, glutathione content less than 25.0 % compared to the placebo group. In animals treated with beer extract of pine needles all anti-oxidative markers of liver catalase activity are significantly differed from that of animals that used purified water. In animals treated with the classic beer technology under normobaric hypoxia model was likely reduce the average lifetime to 313.1 s in terms of lack of oxygen compared to animals treated with purified water. In animals administrated with beer extract of pine needles average lifetime remained intact at figures and had no probable deviations.Conclusions. According to biochemical markers research of anti-oxidative system in liver homogenate of animals, beer with pine needles extract, due to its antioxidative properties, minimizes the negative alcohol impact on the liverthat manifested in less oxidative stress. Beer with pine needles extract does not potentiate the adverse effects of alcohol in acute hypoxic condition and does not reduce the average lifetime of the animal, as opposed to the usual beer. A beer“Emerald” with an extract of pine needles, due to its antioxidant properties, may be an alternative to modern alcoholic beverages and significantly reduce the toxic effects of alcohol.Цель работы – исследовать токсикологические аспекты пива и оценить целесообразность создания новой технологии приготовления пива с добавлением водного экстракта хвои сосны обыкновенной, которой частично заменили хмель. Материалы и методы. Пиво приготовлено по классической рецептуре с добавлением хвойного экстракта (600 мл/дал). Изучали влияние пива с добавлением экстракта хвои сосны обыкновенной на прооксидантно-антиоксидантное состояние печени животных по сравнению с пивом изготовленным по классической рецептуре. Результаты и их обсуждение. Введение животным пива классической технологии в дозе 15 г/кг в течение 14 дней достоверно повышало содержание прооксидантных маркеров в гомогенате печени (ДК на 20,4 %, ТБК-реактантов ‑ на 51,6 %) по сравнению с животными, получавшими плацебо и уменьшало активность каталазы на 40,9 %. Маркеры гомогената печени животных, получавших пиво с экстрактом находились в рамках физиологической нормы. Под влиянием преднизолона (50 мг/кг) содержание диеновых коньюгатов в печени животных, получавших пиво классической технологии на 23,8 % больше, чем у животных, в условиях оксидативного стресса употребляли воду очищенную. Содержание ТБК-реактантов больше на 13,7 %, содержание восстановленного глутатиона меньше на 25,0 % по сравнению с группой плацебо. У животных, получавших пиво с экстрактом все маркеры анти-прооксидантного системы печени и активность каталазы достоверно не отличались от показателей животных, употреблявших воду очищенную. У животных, получавших пиво классической технологии на модели нормобарической гипоксии, было достоверное уменьшение среднего времени жизни на 313,1 с в условиях недостаточности кислорода по сравнению с животными, получавшими воду очищенную. У животных, которым вводили пиво с экстрактом среднее время жизни оставался на уровне интактных показателей и не имел достоверных отклонений. Выводы. Разработанное пиво благодаря своим антиоксидантным свойствам вероятно уменьшит токсическое действие алкоголя на организм человека и может быть альтернативой современным алкогольным напиткам.Мета роботи – дослідити токсикологічні аспекти пива та оцінити доцільність створення нової технології приготування пива з додаванням водного екстракту хвої сосни звичайної, якою частково замінили хміль.Матеріали та методи. Пиво приготували за класичною рецептурою з додаванням хвойного екстракту (600 мл/дал). Вивчали вплив пива з додаванням екстракту хвої сосни звичайної на прооксидантно антиоксидантний стан печінки тварин порівняно з пивом, виготовленим за класичною рецептурою.Результати та їх обговорення. Уведення тваринам пива, виготовленого за класичною технологією, в дозі 15 г/кг протягом 14 днів вірогідно підвищувало вміст прооксидантних маркерів у гомогенаті печінки (ДК на20,4 %, ТБК-реактантів – на 51,6 %) порівняно з тваринами, що отримували плацебо, та зменшувало активність каталази на 40,9 %. Маркери гомогенату печінки тварин, які отримували пиво з екстрактом, знаходилися в межах фізіологічної норми. Під впливом преднізолону (50 мг/кг) вміст дієнових кон`югатів в печінці тварин, що отримували зазначене пиво, збільшувався на 23,8 % порівняно з тваринами, які в умовах оксидативного стресу вживали воду очищену. Вміст ТБК-реактантів більше на 13,7 %, вміст відновленого глутатіону менше на 25,0 % порівняно з групою плацебо. У тварин, що отримували пиво з екстрактом, усі маркери анти-прооксидантноїсистеми печінки й активність каталази вірогідно не відрізнялися від показників тварин, які вживали воду очищену. У тварин, які отримували пиво на моделі нормобаричної гіпоксії, було вірогідне зменшення середньогочасу життя на 313,1 с за умови недостатності кисню порівняно з тваринами, що отримували воду очищену. У тварин, яким уводили пиво з екстрактом, середній час життя залишався на рівні інтактних показників та не мав вірогідних відхилень.Висновки. Розроблене пиво завдяки своїм антиоксидантним властивостям, вірогідно зменшить токсичний вплив алкоголю на організм людини та стане альтернативою сучасним алкогольним напоям
Changing the bonding force of impression tray to edentulous maxillary jaw simulator with impression valve system: In vitro study
Objective: The aim of this study was to evaluate the effect of an impression valve system (IVS) on the bonding force between an impression tray and an edentulous maxillary jaw.Materials and Methods: In this in vitro study, a polyether.coated maxillary jaw simulator (PM) was used to model an edentulous maxillary jaw. The IVS was placed into individual impression trays. An irreversible hydrocolloid impression was taken of the PM when the IVS was open and closed. The impression tray bonding force was measured using a digital dynamometer. Student's t.test was used to determine the significance of the difference between these two groups.Results: The impression tray was more easily separated from the PM when the IVS was open (108 ± 3.9 N). The separation was more difficult when the IVS was closed (153.7 ±14.2 N). The difference between these two findings (P = 0.000) was significant.Conclusion: The use of an IVS facilitates the removal of the impression tray from the mouth when taking impressions from an edentulous maxillary jaw.Key words: Bonding force, impression tray, maxillary ja
The client satisfaction with device: a Rasch validation of the Arabic version in patients with upper and lower limb amputation
BACKGROUND: The Client Satisfaction with Devices (CSD) module of the Orthotics and Prosthetics Users' Survey is an extensively used questionnaire that measures patients' satisfaction with orthosis and prosthesis. However, the validated version for Arabic speakers (CSD-Ar) is only applicable for orthosis users. OBJECTIVES: The aim of this study was to evaluate the psychometric proprieties of the CSD-Ar for prosthetics users. METHODS: The study used a convenience sample of prosthesis users from Saudi Arabia and Turkey (N\u2009=\u2009183), who completed the CSD-Ar. The collected data were analysed using Rasch analysis to evaluate item fit, reliability indices, item difficulty, local item dependency, and differential item functioning (DIF) using WINSTEPS version 4.6.1. RESULTS: Based on the analysis, the four-response Likert-scale was acceptable, as shown by the category functioning test, All eight items did achieve a fit to the Rasch Model [(infit) and (outfit) mean-square 0.75 to 1.3]. Person separation reliability was 0.76, and item separation reliability was 0.94. A principal component analysis (PCA) showed satisfactory unidimensionality and no local item dependency. The DIF analysis showed no notable dependency among items on participant characteristics in terms of age, gender, duration of use, country, and level of amputation. CONCLUSION: This study contributes to the confidence of using CSD-Ar to evaluate users' satisfaction with different prostheses, affirming the need for further refinement of the quality of the outcome measure
УПРАВЛІННЯ ФІНАНСОВОЮ БЕЗПЕКОЮ БАНКІВ: ІНСТРУМЕНТАРІЙ МОДЕЛЮВАННЯ
The article is devoted to the development of the complex of economic and mathematical models to support decision–making on managing commercial banks financial security. Aggregated model of management system of commercial banks financial security is presented. Basic conceptual scheme of the bank’s financial security management is developed.The proposed modern modeling tools on the bases of multivariate, econometric, simulation methods and decision making methods make possible to do integrated complex analysis at all levels of the banking market. The results of research in particular assessment and analysis of the survival and spread of crises in the banking market, the research of the particular bank financial security level dynamics in terms of external and internal factors are the basis for the formation and selection of scenarios of financial security ensuring taking into account the features, opportunities and competitive advantages of each bank. The implementation of the proposed modeling tools of financial security makes possible to improve the efficiency and effectiveness of the commercial bank activity and its financial security level.В работе разработан комплекс экономико–математических моделей поддержки принятия решений по управлению финансовой безопасностью коммерческого банка. Представлена агрегированная модель системы управления финансовой безопасностью коммерческого банка. Разработана базисная концептуальная схема процесса управления финансовой безопасностью коммерческого банка. Предложено современный инструментарий моделирования на основе оценки и анализа выживаемости и распространения кризисных ситуаций на банковском рынке, исследования динамики уровня финансовой безопасности конкретного банка в условиях внешних и внутренних факторов влияния для формирования и выбора сценариев обеспечения финансовой безопасности, их внедрения и оценки эффективности реализации.В роботі розроблено комплекс економіко–математичних моделей підтримки прийняття рішень з управління фінансовою безпекою комерційного банку. Представлена агрегована модель системи управління фінансовою безпекою комерційного банку. Розроблена базисна концептуальна схема процесу управління фінансовою безпекою комерційного банку. Запропоновано сучасний інструментарій моделювання на основі оцінки та аналізу виживаності та розповсюдження кризових ситуацій на банківському ринку, дослідження динаміки рівня фінансової безпеки конкретного банку в умовах зовнішніх і внутрішніх факторів впливу для формування та вибору сценаріїв забезпечення фінансової безпеки, їх впровадження та оцінки ефективності реалізації
Flavor Structure in F-theory Compactifications
F-theory is one of frameworks in string theory where supersymmetric grand
unification is accommodated, and all the Yukawa couplings and Majorana masses
of right-handed neutrinos are generated. Yukawa couplings of charged fermions
are generated at codimension-3 singularities, and a contribution from a given
singularity point is known to be approximately rank 1. Thus, the approximate
rank of Yukawa matrices in low-energy effective theory of generic F-theory
compactifications are minimum of either the number of generations N_gen = 3 or
the number of singularity points of certain types. If there is a geometry with
only one E_6 type point and one D_6 type point over the entire 7-brane for
SU(5) gauge fields, F-theory compactified on such a geometry would reproduce
approximately rank-1 Yukawa matrices in the real world. We found, however, that
there is no such geometry. Thus, it is a problem how to generate hierarchical
Yukawa eigenvalues in F-theory compactifications. A solution in the literature
so far is to take an appropriate factorization limit. In this article, we
propose an alternative solution to the hierarchical structure problem (which
requires to tune some parameters) by studying how zero mode wavefunctions
depend on complex structure moduli. In this solution, the N_gen x N_gen CKM
matrix is predicted to have only N_gen entries of order unity without an extra
tuning of parameters, and the lepton flavor anarchy is predicted for the lepton
mixing matrix. We also obtained a precise description of zero mode
wavefunctions near the E_6 type singularity points, where the up-type Yukawa
couplings are generated.Comment: 148 page
Palmoplantar keratoderma along with neuromuscular and metabolic phenotypes in Slurp1-deficient mice.
Mutations in SLURP1 cause mal de Meleda, a rare palmoplantar keratoderma (PPK). SLURP1 is a secreted protein that is expressed highly in keratinocytes but has also been identified elsewhere (e.g., spinal cord neurons). Here, we examined Slurp1-deficient mice (Slurp1(-/-)) created by replacing exon 2 with β-gal and neo cassettes. Slurp1(-/-) mice developed severe PPK characterized by increased keratinocyte proliferation, an accumulation of lipid droplets in the stratum corneum, and a water barrier defect. In addition, Slurp1(-/-) mice exhibited reduced adiposity, protection from obesity on a high-fat diet, low plasma lipid levels, and a neuromuscular abnormality (hind-limb clasping). Initially, it was unclear whether the metabolic and neuromuscular phenotypes were due to Slurp1 deficiency, because we found that the targeted Slurp1 mutation reduced the expression of several neighboring genes (e.g., Slurp2, Lypd2). We therefore created a new line of knockout mice (Slurp1X(-/-) mice) with a simple nonsense mutation in exon 2. The Slurp1X mutation did not reduce the expression of adjacent genes, but Slurp1X(-/-) mice exhibited all of the phenotypes observed in the original line of knockout mice. Thus, Slurp1 deficiency in mice elicits metabolic and neuromuscular abnormalities in addition to PPK
Blow up for the wave equation with a fractional damping
Abstract. We consider the wave equation with a fractional damping of order between 0 and 1 and a polynomial source. Introducing a new functional and using an argument due to Georgiev and Todorova [1] together with some appropriate estimates, it is proved that some solutions blow up in finite time
Non Equilibrium Electronic Distribution in Single Electron Devices
The electronic distribution in devices with sufficiently small diemnsions may
not be in thermal equilibrium with their surroundings. Systems where the
occupancies of electronic states are solely determined by tunneling processes
are analyzed. It is shown that the effective temperature of the device may be
higher, or lower, than that of its environment, depending on the applied
voltage and the energy dependence of the tunneling rates. The I-V
characteristics become asymmetric. Comparison with recent experiments is made
Phase Structure of a Brane/Anti-Brane System at Large N
We further analyze a class of recently studied metastable string vacua
obtained by wrapping D5-branes and anti-D5-branes over rigid homologous S^2's
of a non-compact Calabi-Yau threefold. The large N dual description is
characterized by a potential for the glueball fields which is determined by an
auxiliary matrix model. The higher order corrections to this potential produce
a suprisingly rich phase structure. In particular, at sufficiently large 't
Hooft coupling the metastable vacua present at weak coupling cease to exist.
This instability can already be seen by an open string two loop contribution to
the glueball potential. The glueball potential also lifts some of the
degeneracy in the vacua characterized by the phases of the glueball fields.
This generates an exactly computable non-vanishing axion potential at large N.Comment: v3: 55 pages, 11 figures, typos correcte
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