56 research outputs found

    Single Z' production at CLIC based on e^- gamma collisions

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    We analyze the potential of CLIC based on e- gamma collisions to search for new ZZ' gauge boson. Single Z' production at e-gamma colliders in two SU(3)_C X SU(3)_L X U(1)_N models: the minimal model and the model with right-handed (RH) neutrinos is studied in detail. Results show that new Z' gauge bosons can be observed at the CLIC, and the cross sections in the model with RH neutrinos are bigger than those in the minimal one.Comment: 11 pages, 4 figures, To appear in JET

    Quartic Gauge Boson Couplings and Tree Unitarity in the SU(3)_C X SU(3)_L X U(1)_N Models

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    The quartic gauge boson couplings in the SU(3)CSU(3)LU(1)N{SU(3)}_C \otimes {SU(3)}_L \otimes {U(1)}_N models are presented. We find that the couplings of four {\it differrent} gauge bosons may have unusual Lorentz structure and the couplings sastify the tree unitarity requirement at high energy limit.Comment: 13 pages, Latex, axodraw.st

    Discrete symmetries, invisible axion and lepton number symmetry in an economic 3-3-1 model

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    We show that Peccei-Quinn and lepton number symmetries can be a natural outcome in a 3-3-1 model with right-handed neutrinos after imposing a Z_11 x Z_2 symmetry. This symmetry is suitably accommodated in this model when we augmented its spectrum by including merely one singlet scalar field. We work out the breaking of the Peccei-Quinn symmetry, yielding the axion, and study the phenomenological consequences. The main result of this work is that the solution to the strong CP problem can be implemented in a natural way, implying an invisible axion phenomenologically unconstrained, free of domain wall formation and constituting a good candidate for the cold dark matter.Comment: 17 pages, Revtex

    A Non Mouse-Adapted Dengue Virus Strain as a New Model of Severe Dengue Infection in AG129 Mice

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    The spread of dengue (DEN) worldwide combined with an increased severity of the DEN-associated clinical outcomes have made this mosquito-borne virus of great global public health importance. Progress in understanding DEN pathogenesis and in developing effective treatments has been hampered by the lack of a suitable small animal model. Most of the DEN clinical isolates and cell culture-passaged DEN virus strains reported so far require either host adaptation, inoculation with a high dose and/or intravenous administration to elicit a virulent phenotype in mice which results, at best, in a productive infection with no, few, or irrelevant disease manifestations, and with mice dying within few days at the peak of viremia. Here we describe a non-mouse-adapted DEN2 virus strain (D2Y98P) that is highly infectious in AG129 mice (lacking interferon-α/β and -γ receptors) upon intraperitoneal administration. Infection with a high dose of D2Y98P induced cytokine storm, massive organ damage, and severe vascular leakage, leading to haemorrhage and rapid death of the animals at the peak of viremia. In contrast, very interestingly and uniquely, infection with a low dose of D2Y98P led to asymptomatic viral dissemination and replication in relevant organs, followed by non-paralytic death of the animals few days after virus clearance, similar to the disease kinetic in humans. Spleen damage, liver dysfunction and increased vascular permeability, but no haemorrhage, were observed in moribund animals, suggesting intact vascular integrity, a cardinal feature in DEN shock syndrome. Infection with D2Y98P thus offers the opportunity to further decipher some of the aspects of dengue pathogenesis and provides a new platform for drug and vaccine testing

    Urban coral reefs: Degradation and resilience of hard coral assemblages in coastal cities of East and Southeast Asia

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    © 2018 The Author(s) Given predicted increases in urbanization in tropical and subtropical regions, understanding the processes shaping urban coral reefs may be essential for anticipating future conservation challenges. We used a case study approach to identify unifying patterns of urban coral reefs and clarify the effects of urbanization on hard coral assemblages. Data were compiled from 11 cities throughout East and Southeast Asia, with particular focus on Singapore, Jakarta, Hong Kong, and Naha (Okinawa). Our review highlights several key characteristics of urban coral reefs, including “reef compression” (a decline in bathymetric range with increasing turbidity and decreasing water clarity over time and relative to shore), dominance by domed coral growth forms and low reef complexity, variable city-specific inshore-offshore gradients, early declines in coral cover with recent fluctuating periods of acute impacts and rapid recovery, and colonization of urban infrastructure by hard corals. We present hypotheses for urban reef community dynamics and discuss potential of ecological engineering for corals in urban areas

    Global, regional, and national burden of Parkinson's disease, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016.

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    BACKGROUND: Neurological disorders are now the leading source of disability globally, and ageing is increasing the burden of neurodegenerative disorders, including Parkinson's disease. We aimed to determine the global burden of Parkinson's disease between 1990 and 2016 to identify trends and to enable appropriate public health, medical, and scientific responses. METHODS: Through a systematic analysis of epidemiological studies, we estimated global, regional, and country-specific prevalence and years of life lived with disability for Parkinson's disease from 1990 to 2016. We estimated the proportion of mild, moderate, and severe Parkinson's disease on the basis of studies that used the Hoehn and Yahr scale and assigned disability weights to each level. We jointly modelled prevalence and excess mortality risk in a natural history model to derive estimates of deaths due to Parkinson's disease. Death counts were multiplied by values from the Global Burden of Disease study's standard life expectancy to compute years of life lost. Disability-adjusted life-years (DALYs) were computed as the sum of years lived with disability and years of life lost. We also analysed results based on the Socio-demographic Index, a compound measure of income per capita, education, and fertility. FINDINGS: In 2016, 6·1 million (95% uncertainty interval [UI] 5·0-7·3) individuals had Parkinson's disease globally, compared with 2·5 million (2·0-3·0) in 1990. This increase was not solely due to increasing numbers of older people, because age-standardised prevalence rates increased by 21·7% (95% UI 18·1-25·3) over the same period (compared with an increase of 74·3%, 95% UI 69·2-79·6, for crude prevalence rates). Parkinson's disease caused 3·2 million (95% UI 2·6-4·0) DALYs and 211 296 deaths (95% UI 167 771-265 160) in 2016. The male-to-female ratios of age-standardised prevalence rates were similar in 2016 (1·40, 95% UI 1·36-1·43) and 1990 (1·37, 1·34-1·40). From 1990 to 2016, age-standardised prevalence, DALY rates, and death rates increased for all global burden of disease regions except for southern Latin America, eastern Europe, and Oceania. In addition, age-standardised DALY rates generally increased across the Socio-demographic Index. INTERPRETATION: Over the past generation, the global burden of Parkinson's disease has more than doubled as a result of increasing numbers of older people, with potential contributions from longer disease duration and environmental factors. Demographic and potentially other factors are poised to increase the future burden of Parkinson's disease substantially

    Endogenous Growth and Publicly Funded Knowledge Accumulation

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    We investigate a centrally planned, infinite horizon, single good economy in which new knowledge is generated in a separate R&D sector with government subsidy. The rate of growth of new ideas is assumed to be linear in the amount of labor devoted to R&D. Perpetual growth in per capita output and consumption is sustained by the spillover effects of knowledge creation. Using an isoelastic social welfare function and a general production function, the unique balanced growth path is characterized and the conditions for balanced growth to take place derived. In analyzing standard balanced growth, we demonstrate that so long as physical capital and knowledge grow at some arbitrarily constant rates along an optimal time path, the two rates must necessarily be equal. Using a Cobb-Douglas production function, the dynamic evolution of the economy is explicitly described in closed form for each state and control variables. In particular, it is shown that the economy either (i) attains the balanced growth path from the initial time, or (ii) converges monotonically to the balanced growth path. An asymptotic balanced growth path along which labor input in manufacturing tends to zero in the long run is ruled out by the tranversality condition on knowledge. Copyright � 2007 The Authors; Journal compilation � 2007 Blackwell Publishing Ltd.

    Electrochemical impedance spectroscopy characterization of nanoporous alumina dengue virus biosensor

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    The Faradaic electrochemical impedance technique is employed to characterize the impedance change of a nanoporous alumina biosensor in response towards the specific binding of dengue serotype 2 (Denv2) viral particles to its serotype 2-specific immunoglobulin G antibody within the thin alumina layer. The optimal equivalent circuit model that matches the impedimetric responses of the sensor describes three distinct regions: the electrolyte solution (Rs), the porous alumina channels (including biomaterials) (Q1, R1) and the conductive electrode substrate layer (Q2, R2). Both channel resistance R1 and capacitance Q1 change in response to the increase of the Denv2 virus concentration. A linear relationship between R1 and Denv2 concentration from 1 to 900 plaque forming unit per mL (pfu mL− 1) can be derived using Langmuir–Freundlich isotherm model. At 1 pfu mL− 1 Denv2 concentration, R1 can be distinguished from that of the cell culture control sample. Moreover, Q1 doubles when Denv2 is added but remains unchanged in the presence of two other non-specific viruses — West Nile virus and Chikungunya virus indicates biosensor specificity can be quantitatively measured using channel capacitance

    High strength Hadfield steel produced using laser powder bed fusion of mixed powders

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    Hadfield steel (HS) containing ∼0.83 wt% Carbon has been manufactured using the laser powder bed fusion (LPBF) of mixed Fe-Mn, pure-Fe and Fe-C powders. Results show that the as-fabricated alloy is fully austenitic with the absence of carbides—a typical feature in the cast alloy that necessitates its solutionizing and quenching. The strength (σy = 595.5 ± 18.1 MPa, σu = 950.2 ± 28.6 MPa) and hardness (318.6 ± 7.1 HV) of the LPBF HS are superior to those of the conventionally fabricated HS, while the impact toughness is similar, and ductility is inferior. The yield strength enhancement is mainly due to the refinement in the grain size and increase in the dislocation density, which occurs due to the rapid solidification conditions that prevail during LPBF. This rapid solidification also prevents carbide formation and retain the main alloying elements (C and Mn) in solution. Thus conventional water quenching process can be completely eliminated
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