140,850 research outputs found

    5G Cellular User Equipment: From Theory to Practical Hardware Design

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    Research and development on the next generation wireless systems, namely 5G, has experienced explosive growth in recent years. In the physical layer (PHY), the massive multiple-input-multiple-output (MIMO) technique and the use of high GHz frequency bands are two promising trends for adoption. Millimeter-wave (mmWave) bands such as 28 GHz, 38 GHz, 64 GHz, and 71 GHz, which were previously considered not suitable for commercial cellular networks, will play an important role in 5G. Currently, most 5G research deals with the algorithms and implementations of modulation and coding schemes, new spatial signal processing technologies, new spectrum opportunities, channel modeling, 5G proof of concept (PoC) systems, and other system-level enabling technologies. In this paper, we first investigate the contemporary wireless user equipment (UE) hardware design, and unveil the critical 5G UE hardware design constraints on circuits and systems. On top of the said investigation and design trade-off analysis, a new, highly reconfigurable system architecture for 5G cellular user equipment, namely distributed phased arrays based MIMO (DPA-MIMO) is proposed. Finally, the link budget calculation and data throughput numerical results are presented for the evaluation of the proposed architecture.Comment: Submitted to IEEE ACCESS. It has 18 pages, 17 figures, and 5 table

    Autonomic and brain morphological predictors of stress resilience

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    Stressful life events are an important cause of psychopathology. Humans exposed to aversive or stressful experiences show considerable inter-individual heterogeneity in their responses. However, the majority does not develop stress-related psychiatric disorders. The dynamic processes encompassing positive and functional adaptation in the face of significant adversity have been broadly defined as resilience. Traditionally, the assessment of resilience has been confined to self-report measures, both within the general community and putative high-risk populations. Although this approach has value, it is highly susceptible to subjective bias and may not capture the dynamic nature of resilience, as underlying construct. Recognizing the obvious benefits of more objective measures of resilience, research in the field has just started investigating the predictive value of several potential biological markers. This review provides an overview of theoretical views and empirical evidence suggesting that individual differences in heart rate variability (HRV), a surrogate index of resting cardiac vagal outflow, may underlie different levels of resilience toward the development of stress-related psychiatric disorders. Following this line of thought, recent studies describing associations between regional brain morphometric characteristics and resting state vagally-mediated HRV are summarized. Existing studies suggest that the structural morphology of the anterior cingulated cortex (ACC), particularly its cortical thickness, is implicated in the expression of individual differences in HRV. These findings are discussed in light of emerging structural neuroimaging research, linking morphological characteristics of the ACC to psychological traits ascribed to a high-resilient profile and abnormal structural integrity of the ACC to the psychophysiological expression of stress-related mental health consequences. We conclude that a multidisciplinary approach integrating brain structural imaging with HRV monitoring could offer novel perspectives about brain-body pathways in resilience and adaptation to psychological stres

    Highlights from RHIC Plus some earlier BNL Highlights in Subnuclear Physics

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    Highlights of the contributions of Brookhaven National Laboratory to Subnuclear Physics are presented together with recent highlights from RHICComment: 16 pages, 20 figures, International Symposium on Subnuclear Physics: Past, Present and Future, Pontifical Academy of Sciences, The Vatican, October 30-November 2,201

    An exploration of ebook selection behavior in academic library collections

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    Academic libraries have offered ebooks for some time, however little is known about how readers interact with them while making relevance decisions. In this paper we seek to address that gap by analyzing ebook transaction logs for books in a university library

    Hydrological response to ~30 years of agricultural surface water management

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    Amongst human practices, agricultural surface-water management systems represent some of the largest integrated engineering works that shaped floodplains during history, directly or indirectly affecting the landscape. As a result of changes in agricultural practices and land use, many drainage networks have changed producing a greater exposure to flooding with a broad range of impacts on society, also because of climate inputs coupling with the human drivers. This research focuses on three main questions: which kind of land use changes related to the agricultural practices have been observed in the most recent years (~30 years)? How does the influence on the watershed response to land use and land cover changes depend on the rainfall event characteristics and soil conditions, and what is their related significance? The investigation presented in this work includes modelling the water infiltration due to the soil properties and analysing the distributed water storage offered by the agricultural drainage system in a study area in Veneto (north-eastern Italy). The results show that economic changes control the development of agro-industrial landscapes, with effects on the hydrological response. Key elements that can enhance or reduce differences are the antecedent soil conditions and the climate characteristics. Criticalities should be expected for intense and irregular rainfall events, and for events that recurrently happen. Agricultural areas might be perceived to be of low priority when it comes to public funding of flood protection, compared to the priority given to urban ones. These outcomes highlight the importance of understanding how agricultural practices can be the driver of or can be used to avoid, or at least mitigate, flooding. The proposed methods can be valuable tools in evaluating the costs and benefits of the management of water in agriculture to inform better policy decision-making

    NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 39)

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    Abstracts are provided for 154 patents and patent applications entered into the NASA scientific and technical information systems during the period Jan. 1991 through Jun. 1991. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

    Some Recent Progress in AdS/CFT

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    Much of modern string theory research concerns AdS/CFT duality, or more generally, gauge/gravity duality. The main subjects are a) Testing and understanding such dualities by exploring how they work for systems with a lot of supersymmetry b) Constructing and exploring approximate string theory duals of QCD c) Applying gauge/gravity duality to other areas of physics such as condensed matter and nuclear physics. I will briefly discuss the first topic.Comment: 13 pages; Contribution to the proceedings of a symposium celebrating the 80th birthday of Murray Gell-Man

    Safeguarding Health at the Workplace: A Study of Work Engagement, Authenticity and Subjective Wellbeing among Religious Workers

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    : Research in work and organizational psychology has paid little attention to religious workers, something certainly surprising as faith-based organizations play a key role in the welfare state of many countries. This research shows that religious workers in a Catholic order present a high degree of subjective wellbeing, both in terms of flourishing and satisfaction with life in general, and a positive balance of positive and negative feelings. More specifically, this study examines the relationship between authenticity and wellbeing amongst religious workers. Survey responses from 142 religious workers in Spain were analyzed using partial least squares path modelling. The results reveal that subjective wellbeing at work is positively related to authenticity. In addition, this relationship is mediated by their level of work engagement

    SU(3) x SU(2) x U(1) Vacua in F-Theory

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    The Standard Model group and matter spectrum is obtained in vacua of F-theory, without resorting to an intermediate unification group. The group SU(3) x SU(2) x U(1)_Y is the commutant to SU(5)_t \times U(1)_Y structure group of a Higgs bundle in E_8 and is geometrically realized as a deformation of I_5 singularity. Lying along the unification groups of E_n, our vacua naturally inherit their unification structure. By modding SU(5)_t out by Z_4 monodromy group, we can distinguish Higgses from lepton doublets by matter parity. Turning on universal G-flux on this part, the spectrum contains three generations of quarks and leptons, as well as vectorlike pairs of electroweak and colored Higgses. Minimal Yukawa couplings is obtained at the renormalizable level.Comment: 40 pages, 1 figur
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