1,023 research outputs found

    An inertial coupled marine power generator for small boats

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    This paper proposes a device to harvest energy from the vertical motion of small boats and yachts. The device comprises a sprung mass coupled to an electrical generator through a ball screw. The mathematical equations describing the dynamics of the system are derived. The equations are used to determine the optimum device parameters, namely its mass, spring constant, ball screw lead, within practical constraints. Simulation results are presented to determine the maximum power that can be generated and the optimum load resistance as a function of boat vibration frequency

    TeV scale resonant leptogenesis from supersymmetry breaking

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    We propose a model of TeV-scale resonant leptogenesis based upon recent models of the generation of light neutrino masses from supersymmetry-breaking effects with TeV-scale right-handed (rhd) neutrinos, NiN_i. The model leads to naturally large cosmological lepton asymmetries via the resonant behaviour of the one-loop self-energy contribution to NiN_i decay. Our model addresses the primary problems of previous phenomenological studies of low-energy leptogenesis: a rational for TeV-scale rhd neutrinos with small Yukawa couplings so that the out-of equilibrium condition for NiN_i decay is satisfied; the origin of the tiny, but non-zero mass splitting required between at least two NiN_i masses; and the necessary non-trivial breaking of flavour symmetries in the rhd neutrino sector. The low mass-scale of the rhd neutrinos and their superpartners, and the TeV-scale AA-terms automatically contained within the model offer opportunities for partial direct experimental tests of this leptogenesis mechanism at future colliders.Comment: 10 Pages latex, version for JHE

    Strongly residual coordinates over A[x]

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    For a domain A of characteristic zero, a polynomial f over A[x] is called a strongly residual coordinate if f becomes a coordinate (over A) upon going modulo x, and f becomes a coordinate upon inverting x. We study the question of when a strongly residual coordinate is a coordinate, a question closely related to the Dolgachev-Weisfeiler conjecture. It is known that all strongly residual coordinates are coordinates for n=2 . We show that a large class of strongly residual coordinates that are generated by elementaries upon inverting x are in fact coordinates for arbitrary n, with a stronger result in the n=3 case. As an application, we show that all Venereau-type polynomials are 1-stable coordinates.Comment: 15 pages. Some minor clarifications and notational improvements from the first versio

    Exploring the decision-making power of Bangladeshi women of reproductive age: Results from a national survey

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    Empowerment is personal, multi-dimensional and latent phenomenon that is difficult to measure directly. Bangladesh is a developing country in South Asia and women population  of the country is almost equal to the male with the male dominant norms. It was aimed to look into the decision making authority and gender role of Bangladeshi women of reproductive age group. Bangladesh Demographic and Health Survey (BDHS) 2014 data was used for the study. A total of 17,863 women of reproductive age were included in this study. The mean age of the respondents was 31 years. About 23.5% respondents had no education and only 11.6% completed primary education. It was found that 68.5% respondents were working and about 73.6% respondents had no NGO (non-governmental organization) membership. Respondents from richest background were more likely to take their own decisions. Urban residence and with higher educational attainment were more likely to take their own decisions. Working status and membership to NGO are significantly associated with decision making power of women. The study revealed that women from urban area, with NGO membership and employed were more empowered. Poor attainment of primary education, low employment, and few NGO memberships are seemed to be the hindrance in women empowerment in Bangladesh. Keywords: Women empowerment, Decision-making, Health seeking behavior, BDHS, Bangladesh

    Health Problems and Health Care Seeking Behaviour of Rohingya Refugees

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    Background: Rohingya refugees are one of the most vulnerable group due to lack of health care system, personal hygiene, shelter, sanitation and violence. Aim: The present study aims to find out the health problems and health care seeking behavior of rohingya refugees, to identify the socio-demographic information for such exposure group in relation to age, sex, occupation, living areas, to explore the patient’s physical, emotional, perceptions, attitudes and environmental health problems and to bring out health care seeking behavior of refugees. Methodology: A cross-sectional study was conducted. A total of 149 samples were selected conveniently for this study from the refugee camps. Data was collected by using mixed type of questionnaire. Descriptive statistic was used for data analysis which has depicted through tables, pie chart and bar chart. Results: The finding of the study showed that 45.6% participants had multiple problems, followed by 16.8% participants who had other specific problems like musculoskeletal pain, visual problems and peptic ulcer. Urinary tract infection was the leading individual health problem with 11.4% of the sample group having it. 10.7% participants had hypertension, 6% had respiratory tract infection, 3.4% had nutrition deficiency, 4.75% had diabetes mellitus and 1.3% had sanitation & hygiene problems. Among the participants, 68.4% age ranged between 15-59 years. The study showed that, only 16.1% participants were satisfied with the quality of service they received while 37.6% participants said that they needed better services such as more laboratory test, radiological imaging, more medicine and more doctors. Conclusion: It is clear that refugees suffered from a variety of health problems, because their living condition and environmental situation were not similar like an independent nation. Further, basic amenities like medicines and other services were not available

    An inertial coupled marine power generator for small boats

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    This paper proposes a device to harvest energy from the vertical motion of small boats and yachts. The device comprises a sprung mass coupled to an electrical generator through a ball screw. The mathematical equations describing the dynamics of the system are derived. The equations are used to determine the optimum device parameters, namely its mass, spring constant, ball screw lead, within practical constraints. Simulation results are presented to determine the maximum power that can be generated and the optimum load resistance as a function of boat vibration frequency

    Patient Satisfaction in Chamber Setting in Bangladesh measured by Patient-Doctor Relationship Questionnaire (PDRQ-9 Bangla)

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    Background: Assessment of patient satisfaction is crucial but there is significant lagging in this sector. Patient satisfaction is an important indicator of health care quality as well as a predictor of treatment adherence. The Good patient-doctor relationship is considered as an integral part of the patient satisfaction. In Bangladesh, this domain is yet to be explored in a large scale. Aim: It was aimed to look into the patient satisfaction level in chamber setting in Bangladesh measured using the patient-doctor relationship questionnaire (PDRQ-9 Bangla). Methods: PDRQ-9 is a short yet excellent tool for assessing the patient-doctor relationship. The data collection was done in private chamber setting by the PDRQ-9 and analyzed. Results: Though the result was not completely in line with the existing literature, the PDRQ-9 was found to be a useful and brief measurement tool in the context of the patient-doctor relationship. Conclusion: Large-scale research in this particular aspect of patient satisfaction in future may provide a more succinct resul

    Sound velocities in solid hydrogen under pressure

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    We present results of semi-empirical lattice dynamics calculations of the sound velocities in solid hydrogen under pressure based on the many-body intermolecular potential and first-principle density-functional theory (DFT). Both the sound velocities and elastic moduli are in excellent agreement with data from Brillouin scattering measurements while Silvera–Goldman and Hemley–Silvera–Goldman potentials tend to overestimate the sound velocity. It is shown that the stiffer is the potential the greater is overestimated the sound velocity. As was the case for equation of state and Raman-active lattice phonon calculations, the employed many-body potential works well for phases I and II (up to ~ 140 GPa while for higher pressures the use of the DFT is preferable

    On the deflection of asteroids with mirrors

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    This paper presents an analysis of an asteroid deflection method based on multiple solar concentrators. A model of the deflection through the sublimation of the surface material of an asteroid is presented, with simulation results showing the achievable orbital deflection with, and without, accounting for the effects of mirror contamination due to the ejected debris plume. A second model with simulation results is presented analyzing an enhancement of the Yarkovsky effect, which provides a significant deflection even when the surface temperature is not high enough to sublimate. Finally the dynamical model of solar concentrators in the proximity of an irregular celestial body are discussed, together with a Lyapunov-based controller to maintain the spacecraft concentrators at a required distance from the asteroid

    Practitioner perceptions regarding the practices of soccer substitutes.

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    Despite empirical observations suggesting that practitioners value the use of substitutions during soccer match-play, limited research has sought to substantiate such claims. This study used online surveys to assess the perceptions of practitioners within professional soccer about the use and practices of substitutes. Thirty-three practitioners completed one of two surveys (each requiring both open and closed questions to be answered), depending upon whether their primary role related mostly to tactical ('tactical practitioners'; n = 7) or physical ('physical practitioners'; n = 26) aspects of player/team management. Thematic content analysis of responses identified four higher-order themes: 'impact of substitutions', 'planning and communication', 'player preparation and recovery' and 'regulations'. Eighty-five percent of practitioners believed that substitutes are important in determining success during soccer match-play, with the primary justification being the perceived ability of such players to provide a physical and/or tactical impact. However, contextual factors such as the match situation, timing of introduction, and players undergoing adequate pre-pitch-entry preparation, may be important for realising such aims. Although many practitioners believed that there was a need for substitutes to engage in bespoke non-match-day preparations and recovery strategies that differ from starting players, logistical considerations, such as scarcity of resources, often limit their scope. Notwithstanding, 96% of respondents indicated that substitutes frequently perform extra conditioning sessions to account for deficits in high-speed running loads compared with players exposed to a longer period of match-play. Substitutes' pre-match warm-ups are typically led by team staff, however practitioners reported providing varying levels of input with regards to the practices adopted between kick-off and pitch-entry. Uncertainty exists as to the efficacy of current pre-pitch-entry practices, and 100% of practitioners highlighted 'preparatory strategies' as at least a 'moderately important' direction for future research. This study presents novel insights and highlights areas that are considered future research priorities amongst those working in the field
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