Distributed Turbo-Like Codes for Multi-User Cooperative Relay Networks

In this paper, a distributed turbo-like coding scheme for wireless networks with relays is proposed. We consider a scenario where multiple sources communicate with a single destination with the help of a relay. The proposed scheme can be regarded as of the decode-and-forward type. The relay decodes the information from the sources and it properly combines and re-encodes them to generate some extra redundancy, which is transmitted to the destination. The amount of redundancy generated by the relay can simply be adjusted according to requirements in terms of performance, throughput and/or power. At the destination, decoding of the information of all sources is performed jointly exploiting the redundancy provided by the relay in an iterative fashion. The overall communication network can be viewed as a serially concatenated code. The proposed distributed scheme achieves significant performance gains with respect to the non-cooperation system, even for a very large number of users. Furthermore, it presents a high flexibility in terms of code rate, block length and number of users.Comment: Submitted to ICC 201

Assessing the Generalisability of Managerial Discretion:An Empirical Investigation in the Arab World

The purpose of this paper is to examine the generalizability of national-level managerial discretion and to assess whether the national context play a role in changing mainstream research findings. Based on a sample of three Arabian countries and using a panel of prominent cross-cultural scholars who provided 138 discretion scores for the sampled countries, we replicate the national framework of Crossland and Hambrick (2011) in a new cultural context. The cultural dimensions were measured via survey responses of 375 middle-managers based on House et al. (2004) cultural practices scale. Consistent with Crossland and Hambrick (2011), we demonstrate that individualism and uncertainty tolerance have the same positive effect on CEOs discretion even in a different cultural setting. In contrast, we show that power distance has a positive and significant effect on managerial discretion. Our results indicate that executives can take idiosyncratic and bold actions to the extent to which the cultural environment allows them to do so. Accordingly, we contribute by showing the importance of the national setting in affecting the generalizability of discretion findings

Strategizing in a Focused Context:Managerial Discretion in the Arab World

The purpose of our study is to broaden the national-level construct of managerial discretion and to investigate the effect of cultural practices on executive discretion. Based on a sample of six Arabian countries and using a panel of prominent cross-cultural scholars who provided 262 discretion scores for the sample countries, we replicate and extend the national framework of Crossland and Hambrick (2011) in a new cultural context. The cultural dimensions were measured using survey responses of middle-managers based on House et al. (2004) cultural practices scale. We extend the national-level framework of managerial discretion and find that an encompassing array of cultural practices play a crucial role in shaping the degree of discretion provided to CEOs. We empirically demonstrate that power distance, future and performance orientation along with gender egalitarianism and assertiveness has positive relationships with managerial discretion. However, institutional collectivism, uncertainty avoidance and humane orientation negatively affect the degree of discretion provided to CEOs. Our study fills a gap in the literature regarding the national-level framework of managerial discretion. Our results indicate that executives can take idiosyncratic and bold actions to the extent to which the cultural environment allows them to do so. Also, we discover new national-level antecedents of managerial discretion that haven’t been considered in earlier studies and confirm the context dependency of this concept

Einstein Geometrization Philosophy and Differential Identities in PAP-Geometry

The importance of Einstein's geometrization philosophy, as an alternative to the least action principle, in constructing general relativity (GR), is illuminated. The role of differential identities in this philosophy is clarified. The use of Bianchi identity to write the field equations of GR is shown. Another similar identity in the absolute parallelism geometry is given. A more general differential identity in the parameterized absolute parallelism geometry is derived. Comparison and interrelationships between the above mentioned identities and their role in constructing field theories are discussed.Comment: LaTeX file, 17 pages, comments and criticism are welcom

How Formal and Informal Institutions of Middle Eastern Countries Influence Managerial Discretion: An Empirical Investigation

Managerial discretion is the focal theme bridging the clash between two schools of thoughts; whether executives have greater influence on their firms’ outcomes or other factors restrain their actions (Hambrick & Finkelstein, 1987). It is argued that constraints come from inertial, normative and environmental forces (e.g. DiMaggio & Powell, 1983). Of these restraints is the institutional environment in which a firm is headquartered. Our paper falls within this research stream and provides an extension for Crossland and Hambrick (2007, 2011) work. We investigate the national level of discretion in new cross-cultural contexts, provide deeper understanding of its concept, and shed the light on undiscovered discretion’s antecedents and consequences. We adopt a quantitative approach in which questionnaires represent our data collection instrument. We anticipate that in high discretion countries firms tend to follow what Miles & Snow (1978) labeled ‘Prospector’ strategy as opposed to low discretion countries in which firms incline to implement a ‘Defender’ strategy

Calli Essential Oils Synergize with Lawsone against Multidrug Resistant Pathogens.

The fast development of multi-drug resistant (MDR) organisms increasingly threatens global health and well-being. Plant natural products have been known for centuries as alternative medicines that can possess pharmacological characteristics, including antimicrobial activities. The antimicrobial activities of essential oil (Calli oil) extracted from the Calligonum comosum plant by hydro-steam distillation was tested either alone or when combined with lawsone, a henna plant naphthoquinone, against MDR microbes. Lawsone showed significant antimicrobial activities against MDR pathogens in the range of 200-300 µg/mL. Furthermore, Calli oil showed significant antimicrobial activities against MDR bacteria in the range of 180-200 µg/mL, Candida at 220-240 µg/mL and spore-forming Rhizopus fungus at 250 µg/mL. Calli oil's inhibition effect on Rhizopus, the major cause of the lethal infection mucormycosis, stands for 72 h, followed by an extended irreversible white sporulation effect. The combination of Calli oil with lawsone enhanced the antimicrobial activities of each individual alone by at least three-fold, while incorporation of both natural products in a liposome reduced their toxicity by four- to eight-fold, while maintaining the augmented efficacy of the combination treatment. We map the antimicrobial activity of Calli oil to its major component, a benzaldehyde derivative. The findings from this study demonstrate that formulations containing essential oils have the potential in the future to overcome antimicrobial resistance

The Path to Entrepreneurship: The Role of Social Networks in Driving Entrepreneurial Learning and Education

This research aims to examine the extent to which the way entrepreneurs learn is reflected in entrepreneurship education, highlighting the existing gap between the literature on entrepreneurial learning and the practice of entrepreneurship education. To explore entrepreneurial learning in-depth, we adopted an interpretivist-constructivist approach that involves participant observation at coworking spaces and semi-structured interviews with entrepreneurs. Data were subsequently analyzed using thematic analysis. Major findings indicate that social networks play a vital role in facilitating entrepreneurial learning, with context and network serving as essential learning mechanisms. However, these elements are often disregarded in traditional entrepreneurship education approaches. This study highlights a gap in the literature where the focus of entrepreneurial learning is primarily on entrepreneurs, while entrepreneurship education primarily focuses on students and educators. The study’s contribution is its emphasis on the importance of social networks in entrepreneurial learning and its potential for redesigning entrepreneurship education. By bridging the gap between entrepreneurial learning and entrepreneurship education, it is possible to create educational approaches that more closely mimic how entrepreneurs learn in real life, potentially leading to more impactful entrepreneurial activity

Spectral relationships of the integral equation with logarithmic kernel in some different domains

In this work, the Fredholm integral equation (FIE) with logarithmic kernel is investigated from the contact problem in the plane theory of elasticity. Then, using potential theory method (PTM), the spectral relationships (SRs) of this integral equation are obtained in some different domains of the contact. Many special cases and new SRs are established and discussed from this work

Resolution of lupus-related left ventricular wall thickening and interstitial lung disease in a child with pulsed steroids and cyclophosphamide

Cardiopulmonary involvement is one of the important manifestations of systemic lupus erythematosus (SLE) that tends to be more common in adults than children with SLE. SLE-related cardiopulmonary affection ranges from subclinical to life threatening condition. Although increased left ventricular mass and interstitial lung disease have been reported in association with SLE, the reversibility of such conditions with treatment of SLE was not sufficiently reported. Herein, we describe a female adolescent with SLE and lupus nephritis class III who presented as well with moderate dyspnea, tachycardia in absence of heart failure and hypertension. She had also productive cough of whitish sputum, no fever and both sputum and blood cultures were negative. Her echocardiography revealed left ventricular wall hypertrophy with preserved systolic function, electrocardiogram showed sinus tachycardia. Her pulmonary function tests revealed mild restrictive pattern and high resolution computed tomography revealed veiling of both lungs with increased attenuation and interstitial nodules with bilateral mild pleural effusion. She received full dose prednisone and intravenous monthly cyclophosphamide in addition to intravenous pulsed methylprednislone. She gradually improved with complete resolution of her cardiopulmonary disease and significant reduction of her proteinuria. In conclusion, cardiopulmonary involvement in relation to SLE could be reversible with adequate treatment leaving