Domain wall solutions with Abelian gauge fields

We study kink (domain wall) solutions in a model consisting of two complex scalar fields coupled to two independent Abelian gauge fields in a Lagrangian that has $U(1)\times U(1)$ gauge plus $\mathbb{Z}_2$ discrete symmetry. We find consistent solutions such that while the U(1) symmetries of the fields are preserved while in their respective vacua, they are broken on the domain wall. The gauge field solutions show that the domain wall is sandwiched between domains with constant magnetic fields.Comment: 11 pages, 6 figures, JHEP for style, but to appear in PLB. Added discussion about the boundary conditions and the physical picture based on superconductivity. Reference adde

Does the CEO elite education affect firm hedging policies?

This paper studies the relationship between CEO elite education and firm hedging decisions. It uses the particular specificities of the French post-secondary educational institutions to examine the effect of CEO educational background on the use of foreign currency derivatives. The results show a positive and significant relationship between education quality and derivatives use. Neither the level nor the type of education has any significant effect. The results also show that the use of derivatives enhances firm performance only when CEOs are from elite institutions. These results are robust to a battery of tests that involve alternative estimation techniques, the use of different subsamples, additional control variables, and control for endogeneity and selection bias

A comparative study of serum electrolytes and lipid levels in ischaemic and haemorrhagic stroke

Background: Stroke or cerebrovasular accident is a major cause of disability worldwide and the second most common cause of death after ischaemic heart disease. There has been a steady increase in incidence of stroke; recent data shows that stroke incidence decreased by 42% in high-income countries and by 100% in low to middle income countries. Aim of the study was to know the association of serum electrolytes and lipid levels in stroke.Methods: This was a retrospective study conducted in June 2014 at tertiary care hospital in South India. Data was obtained from the medical records departments from June 2011 to August 2012. An adult Treatment Panel III criterion was used to classify plasma lipid levels. The serum urea, serum creatinine, serum electrolytes and urinary electrolyte levels were measured by flame photometry. Descriptive statistics has been carried out in the present study. Student ‘t’ test used to test the significance, between the groups and P value of <0.05 were considered as moderately significant, P values of <0.01 was considered highly significant.Results: There was no statistically significant difference in electrolyte levels between ischaemic and haemorrhagic stroke patients. Most common electrolyte imbalance in ischaemic stroke was hyponatremia and most common electrolyte imbalance in Haemorrhagic stroke was hypokalemia. Statistically significant alteration were seen in total cholesterol, LDL and VLDL levels between haemorrhagic and ischaemic stroke.Conclusions: In the present study total cholesterol and HDL levels were higher in haemorrhagic stroke whereas triglycerides, LDL and VLDL were high in ischaemic stroke. Regular monitoring of lipid levels in patients with high risk factors for stroke patients will help in decreasing the mortality and morbidity. Future studies should be prospective, multi-centric and include a large sample size which will help in determining the association between electrolytes and lipid levels in stroke patients

Conceptual Evolution and Fundamental Challenges in Transition from Cold War Security Discourse and Emergence of Human Security Discourse in the Age of Globalization

It is widely accepted that human security is one of the latest, most critical topics in the political science literature and international relations. This concept proposes that the origin or goal of security provision must be human beings. In fact, human security has the concept of 'the human' embedded at the heart of it.With a more extensive interpretation, human security has extended the scope of security and has assessed social and economic issues within this framework. Understanding human security requires the comprehension of its conceptual evolution process. As such, the main issue covered in the current study was understanding the nature of conceptual evolutions of human security in two periods before and after the Cold War. To realize this issue, we evaluated some of the most important international efforts and documents related to the concept and derived the significant factors and subcategories in two periods. Despite following the evolutionary process of human security and becoming one of the most important security discourses, this concept still deals with serious challenges in conceptual and functional areas. Therefore, the second and main question of the present study was: what is the nature of key challenges of human security discourse at national and international levels? To answer this question, we used the exploratory approach and a descriptive-analytical method to explain the most important challenges facing human security in conceptual and functional dimensions

Processing of Polymers Stress Relaxation Curves Using Machine Learning Methods

حاليًا، أحد المجالات الموضوعية لتطبيق طرق التعلم الآلي هو التنبؤ بالخصائص المادية. الهدف من هذا العمل هو تطوير نماذج التعلم الآلي لتحديد الخصائص الريولوجية للبوليمرات من منحنيات استرخاء الإجهاد التجريبية. تقدم الورقة لمحة عامة عن الاتجاهات الرئيسية للنهج الميتاهويرية (البحث المحلي، والخوارزميات التطورية) لحل مشاكل التحسين التوافقي. يتم وصف الخوارزميات الميتاهورية لحل بعض مشاكل تحسين التوافقية المهمة، مع التركيز بشكل خاص على بناء أشجار القرار. تم إجراء تحليل مقارن للخوارزميات لحل مشكلة الانحدار في CatBoost Regressor. . الهدف من الدراسة هو مجموعات البيانات المتولدة التي تم الحصول عليها على أساس منحنيات استرخاء الإجهاد النظرية. وترد جداول البيانات الأولية لنماذج التدريب لجميع العينات، ويجري تحليل إحصائي لخصائص مجموعات البيانات الأولية. كان العدد الإجمالي للتجارب العددية لجميع العينات 346020 اختلافًا. عند تطوير النماذج، تم استخدام طرق CatBoost للذكاء الاصطناعي، وتم استخدام طرق التسوية (تحلل الوزن، وتسوية الوزن المفصول، وزيادة) لتحسين دقة النموذج، وتم استخدام طريقة Z-Score لتطبيع البيانات. نتيجة للدراسة، تم تطوير نماذج ذكية لتحديد المعلمات الريولوجية للبوليمرات المدرجة في معادلة ماكسويل-غوريفيتش غير الخطية المعممة (لزوجة الاسترخاء الأولية، وحدة السرعة) باستخدام مجموعات البيانات المولدة لرابط الإيبوكسي EDT-10 كمثال. بناءً على نتائج اختبار النماذج، تم تقييم جودة النماذج، ورسم رسوم بيانية للتنبؤات للمتدربين وعينات الاختبار، ورسوم بيانية لأخطاء التنبؤ. تستند النماذج الذكية إلى خوارزمية CatBoost ويتم تنفيذها في بيئة دفتر المشتري في بايثون. اجتازت النماذج المشيدة تقييم الجودة وفقًا للمقاييس التالية: MAE و MSE و RMSE و MAPE. كانت القيمة القصوى لتنبؤات خطأ النموذج 0.86 لمقياس MAPE، والقيمة الدنيا لتنبؤات خطأ النموذج كانت 0.001 لمقياس    MSE. تقديرات أداء النموذج التي تم الحصول عليها أثناء الاختبار.Currently, one of the topical areas of application of machine learning methods is the prediction of material characteristics. The aim of this work is to develop machine learning models for determining the rheological properties of polymers from experimental stress relaxation curves. The paper presents an overview of the main directions of metaheuristic approaches (local search, evolutionary algorithms) to solving combinatorial optimization problems. Metaheuristic algorithms for solving some important combinatorial optimization problems are described, with special emphasis on the construction of decision trees. A comparative analysis of algorithms for solving the regression problem in CatBoost Regressor has been carried out. The object of the study is the generated data sets obtained on the basis of theoretical stress relaxation curves. Tables of initial data for training models for all samples are presented, a statistical analysis of the characteristics of the initial data sets is carried out. The total number of numerical experiments for all samples was 346020 variations. When developing the models, CatBoost artificial intelligence methods were used, regularization methods (Weight Decay, Decoupled Weight Decay Regularization, Augmentation) were used to improve the accuracy of the model, and the Z-Score method was used to normalize the data. As a result of the study, intelligent models were developed to determine the rheological parameters of polymers included in the generalized non-linear Maxwell-Gurevich equation (initial relaxation viscosity, velocity modulus) using generated data sets for the EDT-10 epoxy binder as an example. Based on the results of testing the models, the quality of the models was assessed, graphs of forecasts for trainees and test samples, graphs of forecast errors were plotted. Intelligent models are based on the CatBoost algorithm and implemented in the Jupyter Notebook environment in Python. The constructed models have passed the quality assessment according to the following metrics: MAE, MSE, RMSE, MAPE. The maximum value of model error predictions was 0.86 for the MAPE metric, and the minimum value of model error predictions was 0.001 for the MSE metric. Model performance estimates obtained during testing are valid

Impact of Classroom Environment on Students` Performance in English Language

The objectives of the study are to examine impact of classroom environment on the academic performance of students in English language as well as their performance difference by gender. Survey and Correlation research designs were employed. The population of the study involved 183 teachers and 2003 SS III students in the selected schools. 401 students representing 20% and 183 teachers were randomly selected. Self-developed questionnaire and profoma were used for collection of data for this study. The data collected were analysed using descriptive statistics of Mean and Standard Deviation and Multiple Regression Analysis. The findings of the study revealed that classroom environment has strong impact on the academic performance of students in English language. On the gender basis, there was no significant difference in the performance of students. Therefore, it was recommended that school management should provide all necessary facilities in the classroom in order to create enabling environment for students overall development. Keywords: Classroom Environment, Students` Academic Performance &amp; English Language DOI: 10.7176/JEP/10-17-07 Publication date:June 30th 201

SU(5) grand unification on a domain-wall brane from an E_6-invariant action

An SU(5) grand unification scheme for effective 3+1-dimensional fields dynamically localised on a domain-wall brane is constructed. This is achieved through the confluence of the clash-of-symmetries mechanism for symmetry breaking through domain-wall formation, and the Dvali-Shifman gauge-boson localisation idea. It requires an E_6 gauge-invariant action, yielding a domain-wall solution that has E_6 broken to differently embedded SO(10) x U(1) subgroups in the two bulk regions on opposite sides of the wall. On the wall itself, the unbroken symmetry is the intersection of the two bulk subgroups, and contains SU(5). A 4+1-dimensional fermion family in the 27 of E_6 gives rise to localised left-handed zero-modes in the 5^* + 10 + 1 + 1 representation of SU(5). The remaining ten fermion components of the 27 are delocalised exotic states, not appearing in the effective 3+1-dimensional theory on the domain-wall brane. The scheme is compatible with the type-2 Randall-Sundrum mechanism for graviton localisation; the single extra dimension is infinite.Comment: 21 pages, 9 figures. Minor changes to text and references. To appear in Phys. Rev.