928 research outputs found

    Confined Dirac Particles in Constant and Tilted Magnetic Field

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    We study the confinement of charged Dirac particles in 3+1 space-time due to the presence of a constant and tilted magnetic field. We focus on the nature of the solutions of the Dirac equation and on how they depend on the choice of vector potential that gives rise to the magnetic field. In particular, we select a "Landau gauge" such that the momentum is conserved along the direction of the vector potential yielding spinor wavefunctions, which are localized in the plane containing the magnetic field and normal to the vector potential. These wave functions are expressed in terms of the Hermite polynomials. We point out the relevance of these findings to the relativistic quantum Hall effect and compare with the results obtained for a constant magnetic field normal to the plane in 2+1 dimensions.Comment: 10 page

    Cross-Cultural Conflict and Pursuit of Identity in Ameen Rihani’s The Book of Khalid

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    Multiculturalism is an outcome of developing global culture emanating from ceaseless flow of people between nations and intercultural interactions. Crossing the borders results in psychological transformation of the immigrants as their ethnic identity shaped by social, religious, historical and political forces over decades is in continual flux. Though different kinds of responses to the situation of cultural multiplicity may be diagnosed, the fact remains that there are no simplistic ways of dealing with or responding to multiculturalism. The immigrants face cultural clash and find difficulties in acculturating. When the immigrants come to install in another country, they are accosted with a new culture, a new statute and a reserved group of people who do not mix so very easily. Everyone does not have the capacity to adjust their feelings and mind. They form a community of diaspora who are always reminded of their roots in an alien land. The impact of diasporic experiences on immigrants’ psyche depends on their level of belonging in an alien land. Ameen Rihani’s odyssey from Lebanon to United States gives him a cutting edge over his contemporaries to be established as most revered author of Arabs diaspora abroad. Rihani, molded and transformed by the cultures of his countries of origin, movement and settlement, has been earnestly engaged in re-conceptualizing the idea of diaspora as a profitable affair as opposed to the popular beliefs that render immigration and displacement as a condition of loss. His novels are bulging with different protagonists of staunch spirit and calibrating credence who win the tussle with cultural conflict and in the process evolve and finally lost. The aim of this paper is to demonstrate how Rihani’s protagonist  Khalid in his novel of the same name evolves with cultural changes, endeavors for pursuit of identity in both origin and adopted worlds and finally takes control of his destiny

    The perceived needs and coping responses of adolescents in the United Arab Emirates

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    This thesis is concerned with the perceived needs and coping responses of a sample of adolescents in the United Arab Emirates. It is arranged in four sections, further subdivided into nine chapters. Section one contains an outline of the main aims, scope, and the significance and limitations of the study. Information about the UAE and some historical background of the society before and after federation are provided to show the rapid and comprehensive development which has been influencial: social structure, familial changes, and changes in traditional customs. The possible effects upon adolescence in the community are discussed. Section two provides a review of relevant literature. Firstly, the concept of needs, historical background of studies of needs, influences upon the development of needs hierarchies, approaches to the study adolescents' needs, universal needs of adolescence and major issues in the assessment of needs are outlined. Then, definitions, conceptual and methodological issues and theories of coping which have influenced this study are discussed. Differences in coping styles and processes used in response to specific and dispositional needs arousal are considered. The development of adolescent perceptions of needs, the significance of adolescent failure in developing coping skills and cognitive development and its effects upon the perception of needs are examined. Finally, the researcher presents a framework of needs perception and coping responses which is used in the design and the conduct of the empirical study. Section three describes the empirical work of the study. It is in three chapters. Firstly, the aims and the overall design are described. A pilot study involving qualitative and quantitative measures was undertaken in preparation for the design and use of a questionnaire involving a larger sample of adolescents. The main study which involved the construction of a questionnaire to examine adolescents' perceived needs and the coping responses. Responses from 700 young people in the UAE were analyzed to determine types and strengths of perceived needs and differences in coping responses. Some gender differences were also identified and discussed. Section four contains a summary of the main findings, conclusions and recommendations. The three most strongly perceived needs reported by these young people were: to achieve success, to be blessed by God and to feel homeostasis and away from problems; and the least strongly felt needs were: to be beautiful/handsome and to gain people's attention. Some gender differences were noted. In coping responses the findings indicated that boys tend to use denial way of coping to meet their perceived needs more than girls, who tend to use acceptance way of coping more than boys. Interestingly, the findings of this research show a considerable overlap between the perceived needs of adolescents in an Islamic culture and those of adolescents in western cultures. The findings are discussed in relation to the debate in theoretical terms between perception of human behavior as trait-orientated or process-orientated. This section concludes with a discussion of issues and questions raised in the study and with recommendations for further research

    Green IT Model for Gulf Cooperation Council Organisations

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    This research aims to develop a Green IT model that suits the needs of the Gulf Cooperation Council (GCC) countries. A mix-methods approach that combines interviews with a survey was implemented to assess the model critically. The initial model developed for evaluating various Green models to assess the Governance, Social and Cultural, Information Technology and Green Management in GCC. The Green IT model aims to raise sustainability awareness in GCC countries based on their visions

    Physiological Responses, Fear-Related Behaviour And Meat Quality Of Broiler Chickens Subjected To Transportation And Other Stressors

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    Five experiments were conducted to investigate the effects of pre-slaughter process and other stressors on adrenocortical (CORT) reaction, heterophil and lymphocyte ratios (HLR), fear-related behaviour (TI), meat quality, heat shock protein (hsp) 70 expression, performance, mortality and some blood parameters in broiler chickens. In Experiment I, 200 day-old broiler chickens (Cobb x Cobb) showing short or long tonic immobility responses were classified as low-fear (STI) or high-fear (LTI) responders, respectively. On day 41, they were subjected to either crating or heat challenge (34+1oC) for 3 h and its effect on plasma corticosterone concentration, heterophil/lymphocyte ratios and heat shock protein 70 expression in brain tissue were determined. Crating and heat exposure elevated heterophil/lymphocyte ratios in both STI and LTI birds. Circulating corticosterone, however, was higher in LTI than STI birds following crating and heat challenge. Although differences between fear responder groups for hsp 70 were negligible prior to heat challenge, following 3 h of heat exposure, the response was greater for the LTI than the STI group. Both STI and LTI showed similar increases in hsp 70 following crating. In Experiment II, 432 day-old broiler chicks (Cobb x Cobb) were housed either in an (i) environmentally controlled house (CH) which was maintained at 23±1 ºC from day 21 onwards or, (ii) conventional open-sided house (OH) with cyclic temperatures (minimum, 24 ºC; maximum, 34 ºC). Equal number of chicks of each housing system was subjected to either ad libitum feeding (AL) or 60% feed restriction on d 4, 5 and 6 (FR). On day 42, heterophil to lymphocyte ratios (HLR) were significantly lower in OH birds fed AL than those of CH. The CH birds had greater body weights, higher feed intake and better FCR than those of OH. Raising birds under OH, as measured by CORT, was more stressful than CH. The lower CORT in FR birds compared to their AL counterparts suggests improved heat tolerance in the former. Within the AL group, the OH chicks had lower HLR than CH and this could be associated with the more rapid growth rate in the latter. Raising birds in OH, where the birds were exposed to a wide variety of stimuli, shortened TI duration. The FR birds had shorter TI duration than their AL counterparts. In Experiment III, two trials were conducted to investigate the effects of housing system and early age feed restriction on CORT, HLR, heat shock protein (hsp) 70 expression and some blood parameters in response to either day (11:00 h) or night (20:00 h) transportation. Chicks were raised either in an (i) environmentally controlled chamber (CH) which was maintained at 23±1 ºC from day 21, or (ii) conventional open-sided house (OH) with cyclic temperatures (minimum, 24 ºC; maximum, 34 ºC). Equal number of chicks for each housing system was subjected to either ad libitum feeding (AL) or 60% feed restriction on d 4, 5 and 6(FR). On day 42, all the birds from each housing system-feeding regimen subgroup were subjected to road transport either at 11:00 h (Trial 1) or 20:00 h (Trial 2) for 6 hours (h) in open truck. Irrespective of time, transportation resulted in a marked elevation in HLR and CORT, The HLR and CORT data suggested that the magnitude of stress attributed to transportation increased with transit time. The chickens failed to habituate to stress following 6 h of transit. The OH chickens, as measured by HLR and CORT, were less distressed than their CH counterparts following crating and transportation. The improved ability of OH to cope with stress of transportation could be attributed to the greater hsp 70 response. Irrespective of time, FR dampened HLR reaction to transportation. For both day and night transportation, hsp 70 expression increased with transit time. Only day transportation had a consistent effect on serum levels of cholesterol, glucose and electrolytes. Chickens transported during the day had higher serum levels of sodium, chloride, glucose and cholesterol with transit time. In Experiment IV, two trials were conducted to investigate the effects of housing system and early age feed restriction on measurements of TI duration, meat quality and some blood parameters. Chicks raised either in an (i) environmentally controlled chamber (CH) which was maintained at 23±1 ºC from day 21 old, or (ii) conventional open-sided house (OH) with cyclic temperatures (minimum, 24 ºC; maximum, 34 ºC). Equal number of chicks from each housing system was subjected to either ad libitum feeding (AL) or 60% feed restriction on d 4, 5 and 6(FR). On day 42, all the birds from each housing system-feeding regimen were subgrouped to road transport either at 11:00 h (Trial 1) or 20:00 h (Trial 2) for 6 h in an open truck.For both day and night transportation, TI durations increased with transit time. The OH birds which were exposed to a wider variety of stimuli, as measured by TI duration, were less fearful than their CH counterparts. Birds subjected to FR and transported during day had shorter TI duration than those fed AL. Irrespective of transportation time, the muscle glycogen content of broilers reduced markedly following transportation. Higher muscle glycogen content was noticed in the OH birds compared to CH following both day and night transportation. Muscle pH declined with transit time in birds transported during the day. Similar response was not noticed among birds transported at night. Following 2 h of transportation, OH birds had lower muscle pH but the reverse was observed after 6 h of transit. Both day and night transportation reduced serum lactic acid levels. Among the AL birds, the day time transportation lowered serum levels of lactic acid but converse was noted following night transportation. While serum creatine kinase (CK) activity was not affected by duration of transportation, birds transported at night showed lower serum levels of CK with transit time. In Experiment V, the influence of pleasant and unpleasant experiences with human beings, and their combinations, on heat shock protein (hsp) 70 expression, and stress and fear responses in response to road transportation and disease resistance were studied in 750 day-old female broiler chicks. The pleasant treatment involved individual handling and gentle stroking for 30 sec daily from day 1 to 28 (PL). The unpleasant treatment involved individual handling, suspension by both legs, and exposure to noise (97 decibels) for 30 sec daily from day 1 to 28 (UNPL). The combination treatment involved exposure to either PL (day 1 to 14) and subsequently UNPL (day 15 to 28) or UNPL (day 1 to 14) and subsequently PL (day 15 to 28). On day 42, 60 birds per treatment were road transported for 3 h. Transportation resulted in higher HLR and CORT, and longer TI duration. The HLR of the PL birds was significantly lower than other groups. The CORT of PL and UNPL birds were not significantly different but lower than the other groups. Both PL-UNPL and UNPL-PL failed to attenuate HLR and CORT reactions following transportation. Although transportation had negligible effect on serum CK levels, the enzyme levels in PL birds were significantly lower than their control, PL-UNPL and UNPL counterparts. The PL and PL-UNPL birds were less fearful, as indicated by shorter TI duration. Irrespective of human treatment group, the amount of hsp 70 in the brain tissue was significantly higher following transportation. The hsp 70 reaction was significantly greater in the PL birds as compared to other groups. As measured by bursa to body weight ratio and bursal histological lesion score, human contact treatment had no consistent effect on resistance to infectious bursal disease. It can be concluded that subjecting birds to pre-slaughter processes which include handling by humans, crating and transportation elicited both stress and fear reactions, and changes in meat quality and hsp 70 expression. Subjecting birds to early age feed restriction, pleasant human contact and raising birds in conventional open-sided housing system can improve the ability of birds to cope with environmental insults

    Improved Microseismic Signal Detection Using Weighted Particle Motion Linearity Measures

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    Microseismic data provides important information about the subsurface during hydraulic fracturing jobs. However, microseismic signals are not as easy to identify as conventional seismic signals. I developed a new technique to detect microseismic signals by measuring displacement information along with the three-dimensional time coherence analysis of the 3D particles motion (linearity). It was tested on microseismic data from a horizontal well in the Marcellus Shale. The method multiplies the linearity calculation with a function of the amplitude of oscillation that is generated using the envelope. In addition, I developed techniques to detect signals from the new, weighted linearity (or the traditional, unweighted linearity) that help with the goal of more effective signal detection. The results from the new method show that it can detect 16 signals from two microseismic datasets, including barely noticeable (amplitude of 0.0003), weak (amplitude of 0.002), and strong (amplitude of 0.02) signals. These were compared with the results from the traditional, unweighted linearity calculation, where I detect only 9 signals and give results contaminated with noise. This indicates that there is a 40% improvement in signal detection using the new approach. Furthermore, the weighted linearity showed more detail in the signals and less noise compared to unweighted linearity results. With this new approach, I am able to detect signals that unweighted linearity cannot identify, while not compromising the quality of signals detectable by linearity

    Interference coordination for LTE-advanced and FM broadcasting interoperability

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    The surest way to guarantee that multiple wireless systems can concurrently exist harmlessly, when operating in the same or adjacent channel, is by analyzing spectrum overlapping. This paper proposes a more accurate model to evaluate the interference power from co-channel and adjacent channel of orthogonal frequency division multiplexing-based long term evolution-advanced (LTE-Advanced) towards broadcasting frequency modulation systems at 800 MHz. Power spectral density overlapping factor is employed, and closed form of the interference power loss is derived. Numerical results demonstrate that the proposed method evaluates more exact interference power than the advanced minimum coupling loss (A-MCL) method, where the co-channel and adjacent channel interference powers are reduced by 1.3 and 3 dB, correspondingly, compared to that obtained using the AMCL method. This decreases the minimum separation distance between the two systems, which can eventually lead to efficient radio spectrum resources utilization

    A rare telson anomaly in \u3cem\u3eParabuthus liosoma\u3c/em\u3e (Ehrenberg, 1828) (Scorpiones: Buthidae)

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    A rare anomaly of telson vesicle with two functional aculei is observed and discussed in a Parabuthus liosoma (Ehrenberg, 1828) specimen collected from Jizan, Saudi Arabia

    Machine-Learning Classifiers for Malware Detection Using Data Features

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    The spread of ransomware has risen exponentially over the past decade, causing huge financial damage to multiple organizations. Various anti-ransomware firms have suggested methods for preventing malware threats. The growing pace, scale and sophistication of malware provide the anti-malware industry with more challenges. Recent literature indicates that academics and anti-virus organizations have begun to use artificial learning as well as fundamental modeling techniques for the research and identification of malware. Orthodox signature-based anti-virus programs struggle to identify unfamiliar malware and track new forms of malware. In this study, a malware evaluation framework focused on machine learning was adopted that consists of several modules: dataset compiling in two separate classes (malicious and benign software), file disassembly, data processing, decision making, and updated malware identification. The data processing module uses grey images, functions for importing and Opcode n-gram to remove malware functionality. The decision making module detects malware and recognizes suspected malware. Different classifiers were considered in the research methodology for the detection and classification of malware. Its effectiveness was validated on the basis of the accuracy of the complete process