N=2⋆\mathcal{N}=2^\star from Topological Amplitudes in String Theory

In this paper, we explicitly construct string theory backgrounds that realise the so-called $\mathcal N=2^\star$ gauge theory. We prove the consistency of our models by calculating their partition function and obtaining the correct gauge theory spectrum. We further provide arguments in favour of the universality of our construction which covers a wide class of models all of which engineer the same gauge theory. We reproduce the corresponding Nekrasov partition function once the $\Omega$-deformation is included and the appropriate field theory limit taken. This is achieved by calculating the topological amplitudes $F_g$ in the string models. In addition to heterotic and type II constructions, we also realise the mass deformation in type I theory, thus leading to a natural way of uplifting the result to the instanton sector.Comment: 27 page

Instanton Corrections for m and Omega

In this paper, we study instanton corrections in the N=2* gauge theory by using its description in string theory as a freely-acting orbifold. The latter is used to compute, using the worldsheet, the deformation of the Yang-Mills action. In addition, we calculate the deformed instanton partition function, thus extending the results to the non-perturbative sector of the gauge theory. As we point out, the structure of the deformation is extremely similar to the Omega-deformation, therefore confirming the universality of the construction. Finally, we comment on the realisation of the mass deformation using physical vertex operators by exploiting the equivalence between Scherk-Schwarz deformations and freely-acting orbifolds

Topological Amplitudes and the String Effective Action

In this work, we study a class of higher derivative couplings in the string effective action arising at the junction of topological string theory and supersymmetric gauge theories in the $\Omega$-background. They generalise a series of gravitational couplings involving gravitons and graviphotons, which reproduces the topological string theory partition function. The latter reduces, in the field theory limit, to the partition function of the gauge theory in the $\Omega$-background when one if its parameters, say $\epsilon_+$, is set to zero. This suggests the existence of a one-parameter extension called the refined topological string. The couplings considered in this work involve an additional vector multiplet and are evaluated, perturbatively and non-perturbatively, at the string level. In the field theory limit, they correctly reproduce the partition function of the gauge theory in a general $\Omega$-background. Hence, these couplings provide new perspectives toward a worldsheet definition of the refined topological string.Comment: Ph.D. dissertation, 12 figure

Probing the Moduli Dependence of Refined Topological Amplitudes

With the aim of providing a worldsheet description of the refined topological string, we continue the study of a particular class of higher derivative couplings $F_{g,n}$ in the type II string effective action compactified on a Calabi-Yau threefold. We analyse first order differential equations in the anti-holomorphic moduli of the theory, which relate the $F_{g,n}$ to other component couplings. From the point of view of the topological theory, these equations describe the contribution of non-physical states to twisted correlation functions and encode an obstruction for interpreting the $F_{g,n}$ as the free energy of the refined topological string theory. We investigate possibilities of lifting this obstruction by formulating conditions on the moduli dependence under which the differential equations simplify and take the form of generalised holomorphic anomaly equations. We further test this approach against explicit calculations in the dual heterotic theory.Comment: 30 page

Non-Perturbative Nekrasov Partition Function from String Theory

We calculate gauge instanton corrections to a class of higher derivative string effective couplings introduced in [1]. We work in Type I string theory compactified on K3xT2 and realise gauge instantons in terms of D5-branes wrapping the internal space. In the field theory limit we reproduce the deformed ADHM action on a general {\Omega}-background from which one can compute the non-perturbative gauge theory partition function using localisation. This is a non-perturbative extension of [1] and provides further evidence for our proposal of a string theory realisation of the {\Omega}-background.Comment: 23 page

دور لجان التدقيق في الأداء المالي للشركات " دراسة تجريبية على المصارف المدرجة في سوق دمشق للأوراق المالية"

هدف البحث إلى دراسة العلاقة التي تربط بين دور لجان التدقيق والأداء المالي للشركات. ولا سيما المصارف العاملة في سوق دمشق للأوراق المالية, وفي سبيل ذلك فقد قام الباحث بجمع البيانات الخاصة بالمتغير المستقل المتمثل بتكوين لجنة التدقيق من تقارير الحوكمة المنشورة على موقع هيئة الأوراق والأسواق المالية السورية, وكذلك البيانات الخاصة بالمتغير التابع المتمثل بالأداء المالي من خلال القوائم والتقارير المالية الخاصة بالمصارف المدرجة في سوق دمشق للأوراق المالية, وهيئة الأوراق والأسواق المالية السورية, وعددها 14 مصرف وذلك خلال المدة من عام 2009 ولغاية 2017, وقد تمت دراسة البيانات من خلال برنامج Eviews10. وقد توصلت الدراسة إلى مجموعة من النتائج أهمها: توجد علاقة سلبية بين كل من متغيري الاستقلال وعدد اجتماعات لجنة التدقيق مع المدقق الخارجي ومعدل العائد على الأصول وهذه العلاقة غير ذات دلالة إحصائية, كما توجد علاقة موجبة بين متغيري توافر الخبرة المالية والمحاسبية في لجان التدقيق وعدد اجتماعات اللجنة سنوياً مع معدل العائد على الأصول ولكنها غير ذات دلالة إحصائية

The various effects of Nigella sativa on multiple body systems in human and animals

Nigella sativa (Black seeds) has been recognized as one of the most popular herbs in many parts of the world for centuries. It was used in the world as folk medicine to cure different kinds of diseases. This plant has been considered as one of the main sources of nutrition and healthcare for humans as well as animals. It has been perceived as Kalonji; it is a southwest Asian plant that flowers annually. The seeds and oil of this plant have been used in food; in addition, it has a long history in the making of medicines. In addition to its being a model plant for better realization of gene and chromosome relationship, the plant species is also significant cytogenetically. Plant based system has not been absorbed fully for human health care despite the remarkable advancements in the field of pharmacology. Cumin, as one of the medicinal plants gifted to humans by nature, has a number of potential uses. It has been proved to be a useful herbal medicines that can be used for human health and therefore has been extensively studied and investigated to further discover the advantages of this plant

Low switching power neuromorphic perovskite devices with quick relearning functionality

In the quest to reduce energy consumption, there is a growing demand for technology beyond silicon as electronic materials for neuromorphic artificial intelligence devices. Equipped with the criteria of energy efficiency and excellent adaptability, organohalide perovskites can emulate the characteristics of synaptic functions in the human brain. In this aspect, this study designs and develops CsFAPbI3-based memristive neuromorphic devices that can switch at low power and show larger endurance by adopting the powder engineering methodology. The neuromorphic characteristics of the CsFAPbI3-based devices exhibit an ultra-high paired-pulse facilitation index for an applied electric stimuli pulse. Moreover, the transition from short-term to long-term memory requires ultra-low energy with long relaxation times. The learning and training cycles illustrate that the CsFAPbI3-based devices exhibit faster learning and memorization process owing to their larger carrier lifetime compared to other perovskites. The results provide a pathway to attain low-power neuromorphic devices that are synchronic to the human brain's performance

Rethinking justice beyond human rights. Anti-colonialism and intersectionality in the politics of the Palestinian Youth Movement

This article discusses the politics of the Palestinian Youth Movement (PYM) – a contemporary social movement operating across a number of Arab and western countries. Unlike analysis on the Arab Uprisings which focused on the national dimension of youth activism, we explore how the PYM politics fosters and upholds an explicitly transnational anti-colonial and intersectional solidarity framework, which foregrounds a radical critique of conventional notions of self-determination based on state-framed human rights discourses and international law paradigms. The struggle becomes instead framed as an issue of justice, freedom and liberation from interlocking forms and hierarchies of oppression. KEYWORDS: Palestine, transnational social movements, intersectionality, human rights, anti-colonialis