14,579 research outputs found

    An Experiment and Detection Scheme for Cavity-based Cold Dark Matter Searches

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    A resonance detection scheme and some useful ideas for cavity-based searches of light cold dark matter particles (such as axions) are presented, as an effort to aid in the on-going endeavors in this direction as well as for future experiments, especially in possibly developing a table-top experiment. The scheme is based on our idea of a resonant detector, incorporating an integrated Tunnel Diode (TD) and a GaAs HEMT/HFET (High Electron Mobility Transistor/Heterogenous FET) transistor amplifier, weakly coupled to a cavity in a strong transverse magnetic field. The TD-amplifier combination is suggested as a sensitive and simple technique to facilitate resonance detection within the cavity while maintaining excellent noise performance, whereas our proposed Halbach magnet array could serve as a low-noise and permanent solution replacing the conventional electromagnets scheme. We present some preliminary test results which demonstrate resonance detection from simulated test signals in a small optimal axion mass range with superior Signal-to-Noise Ratios (SNR). Our suggested design also contains an overview of a simpler on-resonance dc signal read-out scheme replacing the complicated heterodyne readout. We believe that all these factors and our propositions could possibly improve or at least simplify the resonance detection and read-out in cavity-based DM particle detection searches (and other spectroscopy applications) and reduce the complications (and associated costs), in addition to reducing the electromagnetic interference and background.Comment: 22 pages, 7 figure

    Storage aware data management system for Genomics

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    In recent years, nucleotide sequencing has become increasingly instrumental in both research and clinical settings. This has led to explosive growth in sequencing data produced worldwide along with an increase in complex analysis algorithms. As the amount of data and analysis increases, so does the need for automated solutions for processing and analysis. The concept of workflows has gained favor in the bioinformatics community, but there is little in the scientific literature describing end-to-end operational automation systems. We provided an automation system that aims at providing a solution to the genomics related operational challenges that face sequencing of both research and clinical facilities. We built on existing open-source technologies, with a modular design allowing for a community-driven effort to create plug and play services. In this research, we describe the system and elaborate on the underlying conceptual framework. Which can be reduced to 3 conceptual levels: Data tagging (using metadata automation), Classifying Storage systems (the steps involved in the classification of storage systems), and execution (using a series of rules to move data around on an operational level)

    Insights into APC/C: From cellular function to diseases and therapeutics

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    Anaphase-promoting complex/cyclosome (APC/C) is a multifunctional ubiquitin-protein ligase that targets different substrates for ubiquitylation and therefore regulates a variety of cellular processes such as cell division, differentiation, genome stability, energy metabolism, cell death, autophagy as well as carcinogenesis. Activity of APC/C is principally governed by two WD-40 domain proteins, Cdc20 and Cdh1, in and beyond cell cycle. In the past decade, the results based on numerous biochemical, 3D structural, mouse genetic and small molecule inhibitor studies have largely attracted our attention into the emerging role of APC/C and its regulation in biological function, human diseases and potential therapeutics. This review will aim to summarize some recently reported insights into APC/C in regulating cellular function, connection of its dysfunction with human diseases and its implication of therapeutics

    Health professionals' perceptions of cultural influences on stroke experiences and rehabilitation in Kuwait

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Informa UK Ltd.Purpose: The aim of this study was to investigate the perceptions of health professionals who treat stroke patients in Kuwait regarding cultural influences on the experience of stroke and rehabilitation in Kuwait. Health professionals interviewed were from a variety of cultural backgrounds thus providing an opportunity to investigate how they perceived the influence of culture on stroke recovery and rehabilitation in Kuwait. Method: Semi-structured interviews were carried out with 12 health professionals with current/recent stroke rehabilitation experience in Kuwait, followed by thematic analysis of the verbatim transcripts. Results: The health professionals identified several features of the Kuwaiti culture that they believed affected the experiences of stroke patients. These were religious beliefs, family involvement, limited education and public information about stroke, prevailing negative attitudes toward stroke, access to finances for private treatment, social stigma and the public invisibility of disabled people, difficulties identifying meaningful goals for rehabilitation, and an acceptance of dependency linked with the widespread presence of maids and other paid assistants in most Kuwaiti homes. Conclusion: To offer culturally sensitive care, these issues should be taken into account during the rehabilitation of Kuwaiti stroke patients in their home country and elsewhere

    Imprints of clustering in multiplicity fluctuations

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    In this paper, we investigate the multiplicity fluctuations of charged particles observed in high-energy nuclear collisions and relate them to the size of hadronizing systems which happen during such processes. We use the average multiplicities N\langle N\rangle and variances Var(N)Var\left(N\right) of multiplicity distributions of charged particles produced in centrality selected collisions of relativistic heavy-ion nuclei to evaluate the dynamic variable Ω\Omega and study its dependence on the size of colliding nuclei. We connect the observed system-size dependence of multiplicity fluctuations with the clustering phenomena and the finiteness of the hadronizing sources and the thermal bath

    A robust control design approach for altitude control and trajectory tracking of a quadrotor

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    Introduction. Unmanned aerial vehicles as quadcopters, twin rotors, fixed-wing crafts, and helicopters are being used in many applications these days. Control approaches applied on the quadrotor after decoupling the model or separate altitude control and trajectory tracking have been reported in the literature. A robust linear H∞ controller has been designed for both altitude control and circular trajectory tracking at the desired altitude. Problem. The ability of the quadrotor system to hover at a certain height and track any desired trajectory makes their use in many industrial applications in both military and civil applications. Once a controller has been designed, it may not be able to maintain the desired performance in practical scenarios, i.e. in presence of wind gusts. Originality. This work presents the control strategy to ensure both altitude control and trajectory tracking using a single controller. Purpose. However, there is a need for a single controller that ensures both altitude control and trajectory tracking. Novelty. This paper presents a robust H∞ control for altitude control and trajectory tracking for a six degree of freedom of unmanned aerial vehicles quadrotor. Methodology. Multi input multi output robust H∞ controller has been proposed for the quadrotor for altitude control and tracking the desired reference. For the controller validation, a simulation environment is developed in which a 3D trajectory is tracked by the proposed control methodology. Results. Simulation results depict that the controller is efficient enough to achieve the desired objective at minimal control efforts. Practical value. To verify that the proposed approach is able to ensure stability, altitude control, and trajectory tracking under practical situations, the performance of the proposed control is tested in presence of wind gusts. The ability of the controller to cater to the disturbances within fractions of seconds and maintaining both transient and steady-state performance proves the effectiveness of the controller.Вступ. Безпілотні літальні апарати, такі як квадрокоптери, двороторні апарати, апарати з нерухомими крилами та гелікоптери сьогодні використовуються у багатьох сферах застосування. У літературі повідомляється про підходи до керування, застосовані на квадрокоптері після від’єднання моделі або окремого контролю висоти та відстеження траєкторії. Надійний лінійний регулятор H∞ був розроблений як для контролю висоти, так і для відстеження кругової траєкторії на потрібній висоті. Проблема. Здатність квадрокоптерної системи зависати на певній висоті та відстежувати будь-яку бажану траєкторію робить їх застосування можливим у багатьох сферах як у військових, так і в цивільних цілях. Розроблений контролер може не підтримувати бажані характеристики у реальних умовах, тобто за наявності поривів вітру. Оригінальність. У цій роботі представлена стратегія керування, яка забезпечує як контроль висоти, так і відстеження траєкторії за допомогою одного контролера. Мета. Однак існує потреба в єдиному контролері, який забезпечує як контроль висоти, так і відстеження траєкторії. Новизна. У цій статті представлено надійний регулятор H∞ для контролю висоти та відстеження траєкторії для шести ступенів свободи безпілотних літальних апаратів. Методологія. Для квадрокоптера запропоновано багатовхідний багатовихідний надійний контролер H∞ для контролю висоти та відстеження бажаного курсу. Для перевірки контролера розробляється середовище моделювання, в якому тривимірна траєкторія відстежується за запропонованою методологією керування. Результати. Результати моделювання показують, що контролер є досить ефективним для досягнення бажаної мети при мінімальних зусиллях контролю. Практична цінність. Щоб переконатися, що запропонований підхід здатний забезпечити стабільність, контроль висоти та відстеження траєкторії в реальних ситуаціях, параметри запропонованого контролю перевіряються за наявності поривів вітру. Здатність контролера усувати порушення протягом кількох секунд і підтримувати як перехідні, так і стабільні показники доводить ефективність контролера

    Hydraulic simulations to evaluate and predict design and operation of the Chashma Right Bank Canal

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    Irrigation systems / Irrigation canals / Flow control / Velocity / Canal regulation techniques / Hydraulics / Simulation models / Design / Operations / Crop-based irrigation / Distributary canals / Water delivery / Policy / Protective irrigation / Water allocation / Water requirements / Sedimentation / Water distribution / Equity / Water conveyance / Pakistan / Chashma Right Bank Canal

    Antimicrobial, Cytotoxic and Phytotoxic Potency of Ethyl Acetate Extract of Rhizopus stolonifer Culture

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    Purpose: To evaluate the antimicrobial, cytotoxic and phytotoxic activities of the organic extract of Rhizopus stolonifer whole cell static culture in order to determine the presence of potentially bioactive compounds in the culture.Methods: The organic extract was obtained by extracting the whole cell culture of R. stolonifer with Ethyl Acetate (EtOAc). The antifungal activity was determined by inhibitory effect on the growth of Alternaria alternate, Aspergillus flavus, Curvularia protuberata and Fusarium oxysporum, cytotoxic activity by brine shrimp lethality test, antibacterial activity against Ervinia carotovora and Xanthomonas campestris by disc diffusion technique, and phytotoxic activity by testing the crude extract against theLemna minor frond.Results: The extract showed phytotoxic activity (at 95% level of  significance) against Lemna minor (67.7 % lethality) with Fronds Inhibition (FI50) of 167.85 ìg mL-1. The extract exhibited a significant (at 95% level of significance) cytotoxic activity (LC50 of 115.71 ìg mL-1) against brine shrimp. Maximum mortality (56.7 %) was obtained at a concentration of 200 ìg mL-1 concentration after 48 h. In the antifungal test, the highest inhibitory effect was observed against Fusarium oxysporum (88.8 %)followed by Alternaria alternata (81.5 %), Aspergillus flavus (70.5 %) and Curvularia protuberata (37.5 %) at 1000 ìg. mL-1 when compared to negative reference. Antibacterial activity against Ervinia carotovora and Xanthomonas campestris was minimal even at extract level of 2000 ìg mL-1.Conclusion: The ethyl acetate extract of R. stolonifer possesses significant herbicidal, cytotoxic and antifungal properties. Isolation and  characterization is required for structural elucidation of its bioactivecompounds.Keywords: Rhizopus stolonifer, Antifungal, Antibacterial, Phytotoxicity, Cytotoxicity

    An Improved Algorithm to Solve Transportation Problems for Optimal Solution

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    In this paper, we have developed an algorithm to obtain initial basic feasible solution of transportation problems where the object is to minimize the transportation cost. The proposed method is compared with well-known existing methods including Least-Cost Method and North-West Corner Method and is found to yield better results. Feasible solution from the proposed method leads to solution closest to the optimal solution; and in some numerical examples same as the optimal solution. Key words: Transportation problem, Initial Basic Feasible Solution, Optimal Solutio
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