283 research outputs found

    Universality in the Electroproduction of Vector Mesons

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    We study universality in the electroproduction of vector mesons using a unified nonperturbative approach which has already proved to reproduce extremely well the available experimental data. In this framework, after the extraction of factors that are specific of each vector meson, we arrive at a reduced integrated elastic cross section which is universal. Our calculations suggest a finite infrared behavior for the strong coupling constant.Comment: 22 pages, 10 figure

    Performance Analysis of FBMC and CP-OFDM in the Presence of Phase Noise

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    Multi-Carrier (MC) modulation schemes like Or- thogonal Frequency Division Multiplexing (OFDM) are highly sensitive to Phase Noise (PN). In the case of air interfaces operating in higher frequencies, e.g. the range between 6 and 100 GHz frequently called millimeter wave (mmWave), the PN generated by the local oscillators is even more accentuated. Alternative MC systems are being considered for future mmWave wireless communications. In this contribution, we analytically derive expressions for an upper bound for the interference power generated by the PN in OFDM, DFT-Spread-OFDM and Filter Bank Multi-Carrier (FBMC). Then, we evaluate the performance degradation due to that imperfection in terms of coded and uncoded BER

    Nonlinear Digital Self-Interference Cancellation with Reduced Complexity for Full Duplex Systems

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    Full duplex transmission is currently viewed as an important technology component for the future 5G and beyond mobile broadband technology. In order to realize its promised theoretical gain, sufficient cancellation of the self-interference must be achieved. The focus throughout this work will be on the digital cancellation, which main target is to cancel the residual self-interference resulting from the insufficient analog cancellation due to hardware imperfections, along with non-linearities existing in the transmitter chain. A novel pre-transmission transformation based on the Cholesky decomposition is presented, that aims at enhancing the digital cancellation performance. A digital cancellation based on the transversal recursive least squares with the exploitation of the dichotomous coordinate descent algorithm to lower the computational complexity is presented. The analysis was extended to include the existence of a received signal of interest, while simultaneously canceling the self-interference signal. By means of numerical simulations, a performance evaluation was carried out and results showed that the level of residual interference after the digital canceler reaches the simulated noise floor power level

    PRACTICUM DIRECT Simulator for Decision Making during Pandemics

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    Presented at the 4th XoveTIC Conference, A Coruña, Spain, 7–8 October 2021[Abstract] The past and current situation of the SARS-CoV-2 pandemic has put the entire society, and especially all hospital systems, worldwide to the test. It is essential that health system managers and decision makers optimize the management of resources, even being forced to improvise new units, divert resources usually destined to other functions and/or change the usual care modality by considerably enhancing aspects of telemedicine. Artificial Intelligence (AI) techniques and procedures are of great help in decision making in emergency environments due to severe pandemics because of their predictive capacity. This paper presents the PRACTICUM DIRECT project, which proposes the design and implementation of a tool to assist health system managers in making decisions on the early management of hospital resources. It makes use of AI techniques to identify the most critical variables in each case and build models capable of showing the possibilities and consequences of the decisions taken on resources at each moment of the emergency. It includes a simulator that shows how they would affect management. The current status is that of the selection of the most appropriate variables, taking into account those affected during the SARS-CoV-2 pandemic: infectious diseases, cardio-neuro-circulatory diseases, metabolic diseases and rehabilitative medicine.This research was funded by the General Directorate of Culture, Education and University Management of Xunta de Galicia “PRACTICUM DIRECT” Ref. IN845D-2020/03 and the GRANT FOR THE PROGRAM FOR CONSOLIDATION AND STRUCTURING OF COMPETITIVE RESEARCH UNITS Ref. ED431C 2018/49Xunta de Galicia; IN845D-2020/03Xunta de Galicia; ED431C 2018/4

    Treatment of Retinal Vein Occlusion with Ranibizumab in Clinical Practice: Longer-Term Results and Predictive Factors of Functional Outcome

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    To evaluate long-term results and predictors of efficacy in patients with macular edema due to retinal vein occlusion (RVO) treated with intravitreal ranibizumab in a clinical practice setting.info:eu-repo/semantics/publishedVersio

    Levels and variables associated with psychological distress during confinement due to the coronavirus pandemic in a community sample of Spanish adults

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    Due to the COVID-19 pandemic's consequences and the state of alarm, literature has shown that people worldwide have experienced severe stressors that have been associated with increased prevalence of emotional distress. In this study, we explored psychological distress (depression, anxiety, and somatization symptoms) using an online survey platform in a sample of 1,781 Spanish adults during the confinement due to COVID-19, relationships between distress and sleep problems, affect, pain, sleep, emotional regulation, gender, type of housing, history of psychopathology, and living alone during the confinement, and differences depending on demographic and psychological variables. Results showed that between 25% and 39% of the sample referred to clinically significant levels of distress. In addition, women showed higher levels of distress, negative affect, perception of pain, and cognitive reappraisal and lower levels of emotional suppression and sleep quality than men. A history of psychopathology, being younger, living alone or in a flat was associated with higher distress. Finally, the variables most strongly related to distress were negative and positive affect, levels of pain, sleep quality, and emotional suppression. Our results highlight the important role of emotional suppression, cognitive reappraisal, and loneliness and the impact of being a woman and younger in Spain during the COVID-19 pandemic. Therefore, it would be necessary to provide assessments of distress levels in these population groups and focus psychological preventive and therapeutic online interventions on expressing emotions and preventing loneliness

    The Dynamics of Taro (<em>Colocasia esculenta</em>) through Value Chain Analysis and Crop Accounting in Partido District, Camarines Sur, the Philippines

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    This paper scrutinizes and evaluates the value chain of taro in Partido district, Camarines Sur, the Philippines. Taro (Colocasia Esculenta) is rich in carbohydrates and also a good replacement for wheat flour. However, it is well-known to farmers for its ability to produce a reasonable yield in poor soil conditions with less or no farm inputs. It is this reason why Taro is often grown by resource-limited farmers and regarded as a good source of food security. To tap its full potential, this study was conducted to understand and analyze the flow of Taro. This study employed participatory techniques, crop accounting, and financial analysis. The Taro value chain has varied gender roles, according to this study. It also highlighted why, despite having a choice, farmers frequently chose the less profitable transaction path. It also solved the mystery of low productivity in this locale as compared with the national production. The results also showed the cost build-up of Taro and the profitability of each player in the chain. Farmers usually end up at a 22% profit-to-cost ratio by selling the harvest to the middleman, while sellers usually end up at a 47% profit-to-cost ratio. The existing entry barriers in each chain were also identified with the researchers’ recommendations on how to possibly eliminate or mitigate them. This extensive analysis can be valuable to stakeholders in the Taro value chain in the area, as well as government entity and non-governmental organizations in developing initiatives or projects on behalf of the players

    Observation and analysis of creation, decay, and regeneration of annular soliton clusters in a lossy cubic-quintic optical medium

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    We observe and analyze formation, decay, and subsequent regeneration of ring-shaped clusters of (2+1)-dimensional spatial solitons (filaments) in a medium with the cubic-quintic (focusing-defocusing) self-interaction and strong dissipative nonlinearity. The cluster of filaments, that remains stable over ~17.5 Rayleigh lengths, is produced by the azimuthal modulational instability from a parent ring-shaped beam with embedded vorticity l = 1. In the course of still longer propagation, the stability of the soliton cluster is lost under the action of nonlinear losses. The annular cluster is then spontaneously regenerated due to power transfer from the reservoir provided by the unsplit part of the parent vortex ring. A (secondary) interval of the robust propagation of the regenerated cluster is identified. The experiments use a laser beam (at wavelength 800 nm), built of pulses with temporal duration 150 fs, at the repetition rate of 1 kHz, propagating in a cell filled by liquid carbon disulfide. Numerical calculations, based on a modified nonlinear Schr\"odinger equation which includes the cubic-quintic refractive terms and nonlinear losses, provide results in close agreement with the experimental findings.Comment: To be published in Phys. Rev.

    Deciphering Adipose Tissue Extracellular Vesicles Protein Cargo and Its Role in Obesity

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    The extracellular vesicles (EVs) have emerged as key players in metabolic disorders rising as an alternative way of paracrine/endocrine communication. In particular, in relation to adipose tissue (AT) secreted EVs, the current knowledge about its composition and function is still very limited. Nevertheless, those vesicles have been lately suggested as key players in AT communication at local level, and also with other metabolic peripheral and central organs participating in physiological homoeostasis, and also contributing to the metabolic deregulation related to obesity, diabetes, and associated comorbidities. The aim of this review is to summarize the most relevant data around the EVs secreted by adipose tissue, and especially in the context of obesity, focusing in its protein cargo. The description of the most frequent proteins identified in EVs shed by AT and its components, including their changes under pathological status, will give the reader a whole picture about the membrane/antigens, and intracellular proteins known so far, in an attempt to elucidate functional roles, and also suggesting biomarkers and new paths of therapeutic action
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