Notes on topological insulators

This paper is a survey of the $\mathbb{Z}_2$-valued invariant of topological insulators used in condensed matter physics. The $\mathbb{Z}$-valued topological invariant, which was originally called the TKNN invariant in physics, has now been fully understood as the first Chern number. The $\mathbb{Z}_2$ invariant is more mysterious, we will explain its equivalent descriptions from different points of view and provide the relations between them. These invariants provide the classification of topological insulators with different symmetries in which K-theory plays an important role. Moreover, we establish that both invariants are realizations of index theorems which can also be understood in terms of condensed matter physics.Comment: 62 pages, 3 figure

Same Education, Different Treatment: Analyzing Job-Search Experiences of Ultra-Orthodox Graduates Entering the Israeli Labor Market

In this study we examine employment discrimination against ultra-Orthodox Jewish (Haredi) academic graduates in Israel. During the last decade, attitudes towards higher education and employment within ultra-Orthodox communities in Israel have shifted dramatically, with a growing number of graduates seeking to integrate into the general workforce. During the years 2002-2012, the number of ultra-Orthodox students grew by 1000% and this growth trend is still ongoing. Using questionnaires and interviews, we followed the entire job search process of 492 graduates of the same college, half of them belonging to the ultra-Orthodox community and the other half belonging to the general group. We found that although ultra-Orthodox candidates took longer to find a job, received fewer responses from potential employers, and received fewer invitations for job interviews, they experienced a similar level of job acceptance after being interviewed. We argue that personal interaction between employers and candidates can overcome initial negative biases. Policies encouraging direct communication between minorities/immigrants and the general population may thus have positive influence on the job search process. The conclusions of this study may be applied to other minority groups who share the same language with the general population such as second generation immigrants or other ethnic minorities

The Effects of Chronic Stress on Migraine Relevant Phenotypes in Male Mice

Migraine is a disabling neurological disorder affecting 12% of the world’s population. Stress is a major reported trigger and exacerbator of migraine. We evaluated the effects of two chronic stress paradigms on migraine relevant phenotypes in male C57Bl/6 mice.Methods: Fifty six mice were used in a 14 day social defeat stress (SDS) and twenty three mice were used in a 40 day chronic variable stress (CVS) paradigm. Anxiety measures were evaluated using the open field and elevated plus maze (EPM) tests. Migraine relevant phenotypes were evaluated using the nitroglycerin (NTG) and cortical spreading depression (CSD) models.Results: Stress sensitive SDS mice and chronically stressed CVS mice showed decreased exploration in the open field and reduced time spent in the open arms of the EPM compared to controls. Stress sensitive and resilient SDS mice had increased serum corticosterone levels, and stressed mice in the CVS paradigm had decreased weight gain compared to controls, providing combined behavioral and physiological evidence of a stress response. In the CVS paradigm but not the SDS paradigm, the stressed group showed a significant decrease in baseline mechanical withdrawal threshold compared to controls. All groups showed a significant reduction in withdrawal threshold after treatment with NTG, but the reduction was not larger in SDS or CVS than in controls. Interestingly, stress resilient SDS mice showed a rapid recovery from NTG effects that was not seen in other groups. No difference in CSD frequency or velocity was seen between stress and control mice in either stress paradigms.Conclusion: We observed distinct effects of stress on generalized pain response, migraine relevant pain, and migraine relevant excitability. CVS but not SDS was associated with a reduced mechanical withdrawal threshold, consistent with a generalized pain response to chronic stress. Neither SDS nor CVS exacerbated phenotypes considered specifically relevant to migraine - withdrawal to NTG, and susceptibility to CSD. However, the significantly reduced response of stress resilient mice to the NTG stimulus may represent a specific migraine-resistant phenotype

Измерение энергии тепловых потерь мощного светодиодного модуля

Разработана и реализована методика измерения тепловых характеристик мощного светодиодного модуля. Методика позволяет с достаточной точностью определять мощность тепловых потерь. Результаты измерений подтверждаются измерениями мощности световой энергии, излучаемой светодиодным модулем с помощью калиброванного спектрорадиометрического комплекса.The methods of measuring heat characteristics of high power LED module are developed and implemented. The methods enable with sufficient accuracy to determine heat loss power. Measurement results are confirmed by measurements of the power of light energy emitted by LED module with the use of calibrated spectraradiometric complex

Аналитическая зависимость для послойной деформации металлофторопластовой полосы

Тез. докл. VIII Междунар. науч.-техн. конф. (науч. чтения, посвящ. П. О. Сухому), Гомель, 28–29 окт. 2010 г

Zurich Consensus: German Expert Opinion on the St. Gallen Votes on 15 March 2009 (11th International Conference at St. Gallen: Primary Therapy of Early Breast Cancer)

A German working group of 23 breast cancer experts discussed the results from the vote at this year's St. Gallen Consensus Conference on Primary Therapy for Early Breast Cancer ( March 11-14, 2009) and came up with some concrete recommendations for day-to-day therapeutic decisions in Germany. Due the fact that the concept of the St. Gallen Consensus Conference merely allows for a minimal consensus, the objective of the working group was to provide practice-related recommendations for day-to-day clinical decisions in Germany. One area of emphasis at St. Gallen was tumor biology as a starting point for reaching individual therapeutic decisions. Intensive discussion was necessary with respect to the clinical relevance of predictive and prognostic factors. A new addition to the area of systemic therapy was a first-ever discussion of the adjuvant administration of bisphosponates and the fact that therapy with trastuzumab in HER2 overexpressing breast cancer has been defined as the standard for neoadjuvant therapy. The value of taxanes as a component of (neo) adjuvant chemotherapy as well as the value of aromatase inhibitors for the endocrine adjuvant treatment of postmenopausal patients were affirmed