825 research outputs found

    Coalition Stability with Heterogeneous Agents

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    We analyze coalition formation with heterogeneous agents based on an individual stability concept. Defining exchanging and refractory agents, we give existence and enlargement conditions for coalitions with heterogeneous agents. Using the concept of exchanging agents we give necessary conditions for internal stability and show that refraction is a sufficient condition for the failure of an enlargement of the coalition.Heterogeneity, Coalition, Exchanging, Refraction.

    IDENTIFIKASI MISKONSEPSI PESERTA DIDIK PADA MATERI GERAK PARABOLA DI SMA TARUNA BUMI KHATULISTIWA

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    AbstractThis study aims to describe and find the causes of misconceptions among students at SMA TarunaBumi Khatulistiwa about parabolic motion. This misconception causes the learning objectives ofstudents at SMA Taruna Bumi Khatulistiwa not to be achieved. Based on the interview, there were3 causes of misconceptions experienced by students at Taruna Bumi Khatuliwa Senior HighSchool that were expressed directly by the teaching teacher, including: 1.Lack of students'numeracy skills in solving equations, 2. Students experiencing misconceptions in analyzingphenomenon of parabolic motion, 3. Lack of student interest in learning physics, especiallyparabolic motion. It is for this reason that the authors want to identify the causes and types ofmisconceptions experienced by students at SMA Taruna Bumi Khatulistiwa. The method used isa simple descriptive method with a sample of the entire population of class XI MIPA, as many as55 people. Data collection uses diagnostic tests with open reasons and interviews. The results ofthe analysis showed that students' misconceptions reached 41.57% about the motion of theparabola and the rest did not answer the questions given. Based on the results of interviews withstudents, the causes of misconceptions originating from the students themselves on parabolicmotion material include: students' initial conception, incomplete reasons and student abilities.These findings are expected to be used as material for consideration in choosing the appropriatetreatment to overcome students' misconceptions.Keywords: Identification, Misconception, Projectile motio

    Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas

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    The coupling of the spin of electrons to their motional state lies at the heart of recently discovered topological phases of matter. Here we create and detect spin-orbit coupling in an atomic Fermi gas, a highly controllable form of quantum degenerate matter. We reveal the spin-orbit gap via spin-injection spectroscopy, which characterizes the energy-momentum dispersion and spin composition of the quantum states. For energies within the spin-orbit gap, the system acts as a spin diode. To fully inhibit transport, we open an additional spin gap, thereby creating a spin-orbit coupled lattice whose spinful band structure we probe. In the presence of s-wave interactions, such systems should display induced p-wave pairing, topological superfluidity, and Majorana edge states

    The Effects of Vortex Generator Types on Heat Transfer and Flow Structure in a Rectangular Duct Flows

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    In this numerical study a detailed evaluation of the heat transfer characteristics and flow structure in a laminar and turbulent flow through a rectangular channel containing built-in of different type vortex generator has been a accomplished in a range of Reynolds number between 500 and 100,000.A modified version of ESCEAT code has been used to solve Navier-Stokes and energy equations. The purpose of this paper is to present numerical comparisons in terms of temperature, Nusselt number and flow patterns on several configurations of longitudinal vortex generator including new five cases. The structures of heat and flow were studied, using iso-contours of velocity components, vortices, temperature and Nusselt number. This study shows that the predicted structures of fluid flow, temperature fields and Nusselt number variation are strongly affected by the presence of the turbulators. Staggered arrangement gains high Nusselt number, also the lower and upper arrangements have higher Nusselt number than plane duct. High Reynolds number (higher air inlet velocity) will enhance the Nusselt number. Increase in ribs height will enhance the heat transfer as it works as surface area and turbulator at the same time

    Vulnerability to Heat-related Mortality: A Systematic Review, Meta-analysis, and Meta-regression Analysis

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    International audienceBACKGROUND: Addressing vulnerability to heat-related mortality is a necessary step in the development of policies dictated by heat action plans. We aimed to provide a systematic assessment of the epidemiologic evidence regarding vulnerability to heat-related mortality. METHODS: Studies assessing the association between high ambient temperature or heat waves and mortality among different subgroups and published between January 1980 and August 2014 were selected. Estimates of association for all the included subgroups were extracted. We assessed the presence of heterogeneous effects between subgroups conducting Cochran Q tests. We conducted random effect meta-analyses of ratios of relative risks (RRR) for high ambient temperature studies. We performed random effects meta-regression analyses to investigate factors associated with the magnitude of the RRR. RESULTS: Sixty-one studies were included. Using the Cochran Q test, we consistently found evidence of vulnerability for the elderly ages \textgreater85 years. We found a pooled RRR of 0.99 (95% confidence interval [CI] = 0.97, 1.01) for male sex, 1.02 (95% CI = 1.01, 1.03) for age \textgreater65 years, 1.04 (95% CI = 1.02, 1.07) for age \textgreater75 years, 1.03 (95% CI = 1.01, 1.05) for low individual socioeconomic status (SES), and 1.01 (95% CI = 0.99, 1.02) for low ecologic SES. CONCLUSIONS: We found strongest evidence of heat-related vulnerability for the elderly ages \textgreater65 and \textgreater75 years and low SES groups (at the individual level). Studies are needed to clarify if other subgroups (e.g., children, people living alone) are also vulnerable to heat to inform public health program
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