40,395 research outputs found

    Undocumented Queer Latinx Students: Testimonio of Survival

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    Recent U.S. political turmoil has deliberately embedded fear into many marginalized and underrepresented people living in the U.S. The fact that the United States was founded on the demanding work of diverse populations of immigrants is vitally important to how immigrants are being treated today. In 2016, the U.S. presidential electoral win for Donald Trump left many marginalized communities—including Undocumented Queer Latinx students—fearful of how his administration would affect their communities. This paper reviews literatures on Queer immigration history, the homophobic and transphobic psychological history behind legal immigration barriers, and the recent mobilization to include Undocumented Queer Latinx students in the Immigration Rights Movement as foundational elements for an ethnographic research case study of the Undocumented Queer Latinx student community. The historical and current adversities these students face will be the main point of this research due to the increased legal barriers, deportations, and uncertain future that extremely conservative politicians have set―or will set―in motion. The proposed project explores the intersectionality of the historical heterosexism of immigration law, current government debate over DACA, Queer Manifestos about immigration rights, and the gray politics that emphasize the importance of Undocumented Queer Latinx student voices. This research is a subject not many mainstream media sources investigate; however, it is vitally important due to the injustices faced by this community

    Natural and laser-induced cavitation in corn stems: On the mechanisms of acoustic emissions

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    Water in plant xylem is often superheated, and therefore in a meta-stable state. Under certain conditions, it may suddenly turn from the liquid to the vapor state. This cavitation process produces acoustic emissions. We report the measurement of ultrasonic acoustic emissions (UAE) produced by natural and induced cavitation in corn stems. We induced cavitation and UAE in vivo, in well controlled and reproducible experiments, by irradiating the bare stem of the plants with a continuous-wave laser beam. By tracing the source of UAE, we were able to detect absorption and frequency filtering of the UAE propagating through the stem. This technique allows the unique possibility of studying localized embolism of plant conduits, and thus to test hypotheses on the hydraulic architecture of plants. Based on our results, we postulate that the source of UAE is a transient "cavity oscillation" triggered by the disruptive effect of cavitation inception.Comment: 8 pages, 5 figure

    Comment on Singularity-free Cosmological Solutions with Non-rotating Perfect Fluids

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    A conjecture stated by Raychaudhuri which claims that the only physical perfect fluid non-rotating non-singular cosmological models are comprised in the Ruiz-Senovilla and Fernandez-Jambrina families is shown to be incorrect. An explicit counterexample is provided and the failure of the argument leading to the result is explicitly pointed out.Comment: LaTeX, 5 page

    Using a ‘wellbeing’ cost-effectiveness approach to improve resource allocation in social care

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    The promotion of wellbeing is the newly-stated guiding principle for the long-term care (social care) system in England. It signals a shift away from a focus on care need ‘deficits’ approach. Such a change in perspective has the potential to substantially alter how public care systems operate. The practical challenges are significant, both in the interpretation of wellbeing goals and in determining how the care system might be configured to achieve them. The main aim of this paper is to contrast a needs-led resource allocation system with one using a maximising wellbeing approach; that is, one based on: measuring the wellbeing consequences of using services and applying the principles of cost-effectiveness and opportunity cost. As a precursor, the paper also describes how a maximising wellbeing approach might be applied in the case of long-term care. We argue that in theory a maximising wellbeing approach with full information will produce greater total wellbeing improvement for the same budget than a needs-based system. In practice, the comparison will depend on: (a) whether we can actually measure wellbeing in a way that is consistent with the policy goals; (b) the availability of cost-effectiveness information; and (c) the decision rules used to implement a maximising wellbeing approach

    Single-photon exchange interaction in a semiconductor microcavity

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    We consider the effective coupling of localized spins in a semiconductor quantum dot embedded in a microcavity. The lowest cavity mode and the quantum dot exciton are coupled and close in energy, forming a polariton. The fermions forming the exciton interact with localized spins via exchange. Exact diagonalization of a Hamiltonian in which photons, spins and excitons are treated quantum mechanically shows that {\it a single polariton} induces a sizable indirect exchange interaction between otherwise independent spins. The origin, symmetry properties and the intensity of that interaction depend both on the dot-cavity coupling and detuning. In the case of a (Cd,Mn)Te quantum dot, Mn-Mn ferromagnetic coupling mediated by a single photon survives above 1 K whereas the exciton mediated coupling survives at 15 K.Comment: 4 pages, 3 figure

    De retibus socialibus et legibus momenti

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    Online Social Networks (OSNs) are a cutting edge topic. Almost everybody --users, marketers, brands, companies, and researchers-- is approaching OSNs to better understand them and take advantage of their benefits. Maybe one of the key concepts underlying OSNs is that of influence which is highly related, although not entirely identical, to those of popularity and centrality. Influence is, according to Merriam-Webster, "the capacity of causing an effect in indirect or intangible ways". Hence, in the context of OSNs, it has been proposed to analyze the clicks received by promoted URLs in order to check for any positive correlation between the number of visits and different "influence" scores. Such an evaluation methodology is used in this paper to compare a number of those techniques with a new method firstly described here. That new method is a simple and rather elegant solution which tackles with influence in OSNs by applying a physical metaphor.Comment: Changes made for third revision: Brief description of the dataset employed added to Introduction. Minor changes to the description of preparation of the bit.ly datasets. Minor changes to the captions of Tables 1 and 3. Brief addition in the Conclusions section (future line of work added). Added references 16 and 18. Some typos and grammar polishe

    PVT-Robust CMOS Programmable Chaotic Oscillator: Synchronization of Two 7-Scroll Attractors

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    Designing chaotic oscillators using complementary metal-oxide-semiconductor (CMOS) integrated circuit technology for generating multi-scroll attractors has been a challenge. That way, we introduce a current-mode piecewise-linear (PWL) function based on CMOS cells that allow programmable generation of 2–7-scroll chaotic attractors. The mathematical model of the chaotic oscillator designed herein has four coefficients and a PWL function, which can be varied to provide a high value of the maximum Lyapunov exponent. The coefficients are implemented electronically by designing operational transconductance amplifiers that allow programmability of their transconductances. Design simulations of the chaotic oscillator are provided for the 0.35μ m CMOS technology. Post-layout and process–voltage–temperature (PVT) variation simulations demonstrate robustness of the multi-scroll chaotic attractors. Finally, we highlight the synchronization of two seven-scroll attractors in a master–slave topology by generalized Hamiltonian forms and observer approach. Simulation results show that the synchronized CMOS chaotic oscillators are robust to PVT variations and are suitable for chaotic secure communication applications.Universidad Autónoma de Tlaxcala CACyPI-UATx-2017Program to Strengthen Quality in Educational Institutions C/PFCE-2016-29MSU0013Y-07-23National Council for Science and Technology 237991 22284

    A wide family of singularity-free cosmological models

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    In this paper a family of non-singular cylindrical perfect fluid cosmologies is derived. The equation of state corresponds to a stiff fluid. The family depends on two independent functions under very simple conditions. A sufficient condition for geodesic completeness is provided.Comment: 7 pages, RevTeX

    Local null controllability of the N-dimensional Navier-Stokes system with N-1 scalar controls in an arbitrary control domain

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    In this paper we deal with the local null controllability of the N-dimensional Navier-Stokes system with internal controls having one vanishing component. The novelty of this work is that no condition is imposed on the control domain

    Pathological element-based active device models and their application to symbolic analysis

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    This paper proposes new pathological element-based active device models which can be used in analysis tasks of linear(ized) analog circuits. Nullators and norators along with the voltage mirror-current mirror (VM-CM) pair (collectively known as pathological elements) are used to model the behavior of active devices in voltage-, current-, and mixed-mode, also considering parasitic elements. Since analog circuits are transformed to nullor-based equivalent circuits or VM-CM pairs or as a combination of both, standard nodal analysis can be used to formulate the admittance matrix. We present a formulation method in order to build the nodal admittance (NA) matrix of nullor-equivalent circuits, where the order of the matrix is given by the number of nodes minus the number of nullors. Since pathological elements are used to model the behavior of active devices, we introduce a more efficient formulation method in order to compute small-signal characteristics of pathological element-based equivalent circuits, where the order of the NA matrix is given by the number of nodes minus the number of pathological elements. Examples are discussed in order to illustrate the potential of the proposed pathological element-based active device models and the new formulation method in performing symbolic analysis of analog circuits. The improved formulation method is compared with traditional formulation methods, showing that the NA matrix is more compact and the generation of nonzero coefficients is reduced. As a consequence, the proposed formulation method is the most efficient one reported so far, since the CPU time and memory consumption is reduced when recursive determinant-expansion techniques are used to solve the NA matrix.Promep-Mexico UATLX-PTC-088Junta de Andalucía TIC-2532Ministerio de Educación y Ciencia TEC2007-67247, TEC2010-14825UC-MEXUS-CONACyT CN-09-31
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