12,149 research outputs found

    There are no abnormal solutions of the Bethe-Salpeter equation in the static model

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    The four-point Green's function of static QED, where a fermion and an antifermion are located at fixed space positions, is calculated in covariant gauges. The bound state spectrum does not display any abnormal state corresponding to excitations of the relative time. The equation that was established by Mugibayashi in this model and which has abnormal solutions does not coincide with the Bethe-Salpeter equation. Gauge transformation from the Coulomb gauge also confirms the absence of abnormal solutions in the Bethe-Salpeter equation.Comment: 11 pages, late

    Association of Urinary Vitamin D-binding Protein and Megalin as Biomarkers for Diabetic Nephropathy in Type 2 Diabetes Mellitus in Qatari Patients

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    Abstract Background: Nephropathy is a common complication of type 2 diabetes mellitus (T2DM). Previous studies revealed that T2DM patients with nephropathy have higher concentrations of urinary Vitamin D Binding Protein (VDBP) that carries vitamin D to the target tissues, and megalin that mediates endocytosis in the proximal tubule than those who are healthy. Methodology: 196 urine samples with their blood data were obtained from Qatar Biobank, of which 21 samples were measured for VDBP and megalin using enzyme-linked immunosorbent assay (ELISA). They were divided intothree groups; group 1 (control group with eGFR ≥ 90 mL/min/1.73 m²), group 2 (T2DM patients with eGFR ≥ 90 mL/min/1.73 m²) and group 3; (T2DM patients with eGFR < 90 mL/min/1.73 m²). Results: Urinary VDBP and Megalin levels were non-significantly elevated in T2DM patients with DN (P=0.198) and (P=0.293) respectively. Moreover, a weak negative correlation was observed between the urinary VDBP and Megalin levels with eGFR (r=-0.326, P=0.149) and (r=-0.315, P=0.165) respectively. Conclusion: Previous studies revealed that uVDBP and Megalin are potential biomarkers for DN in T2DM patients. However, the current study reveals that urinary VDBP and megalin levels were non-significantly elevated in T2DM patients with DN. Furthermore, eGFR showed a weak negative correlation with urinary VDBP and megalin levels. However, it is suggested that these results could be due to some limitations. Further tests should be performed on larger sample size to confirm the association of Megalin and VDBP in T2DM nephropathy

    Large NcN_c Universality of The Baryon Isgur--Wise Form Factor: The Group Theoretical Approach

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    In a previous article, it has been proved under the framework of chiral soliton model that the same Isgur--Wise form factor describes the semileptonic ΛbΛc\Lambda_b\to\Lambda_c and Σb()Σc()\Sigma^{(*)}_b\to\Sigma^{(*)}_c decays in the large NcN_c limit. It is shown here that this result is in fact independent of the chiral soliton model and is solely the consequence of the spin-flavor SU(4) symmetry which arises in the baryon sector in the large NcN_c limit.Comment: 10 pages in REVTeX, no figure

    Antibody responses to nasopharyngeal carriage of Streptococcus pneumoniae in adults: A longitudinal household study

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    Background. Natural immunity to Streptococcus pneumoniae is thought to be induced by exposure to S. pneumoniae or cross-reactive antigens. No longitudinal studies of carriage of and immune responses to S. pneumoniae have been conducted using sophisticated immunological laboratory techniques.Methods. We enrolled 121 families with young children into this study. Nasopharyngeal (NP) swabs were collected monthly for 10 months from all family members and were cultured in a standard fashion. Cultured S. pneumoniae isolates were serotyped. At the beginning (month 0) and end (month 10) of the study, venous blood was collected from family members 118 years old. Serotype-specific antipolysaccharide immunoglobulin G (IgG) and functional antibody and antibodies to pneumolysin, pneumococcal surface protein A (PspA), and pneumococcal surface antigen A (PsaA) were measured in paired serum samples.Results. Levels of anticapsular IgG increased significantly after carriage of serotypes 9V, 14, 18C, 19F, and 23F by an individual or family member. For serotype 14, a higher level of anticapsular IgG at the beginning of the study was associated with reduced odds of carriage (P = .0006). There was a small (similar to 20%) but significant increase in titers of antibodies to PsaA and pneumolysin but no change in titers of antibody to PspA.Conclusions. Adults respond to NP carriage by mounting anticapsular and weak antiprotein antibody responses, and naturally induced anticapsular IgG can prevent carriage

    On the polarization properties of the charmed baryon Lambda^+_c in the Lambda^+_c -> p + K^- + pi^+ + pi^0 decay

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    The polarization properties of the charmed Lambda^+_c baryon are investigated in weak non-leptonic four-body Lambda^+_c -> p + K^- + pi^+ + pi^0 decay. The probability of this decay and the angular distribution of the probability are calculated in the effective quark model with chiral U(3)XU(3) symmetry incorporating Heavy Quark Effective theory (HQET) and the extended Nambu-Jona-Lasinio model with a linear realization of chiral U(3)XU(3) symmetry. The theoretical value of the probability of the decay Lambda^+_c -> p + K^- + pi^+ + pi^0 relative to the probability of the decay Lambda^+_c -> p + K^- + pi^+ does not contain free parameters and fits well experimental data. The application of the obtained results to the analysis of the polarization of the Lambda^+_c produced in the processes of photo and hadroproduction is discussed.Comment: 10 pages, no figures, Late

    Fermi Surface reconstruction in the CDW state of CeTe3 observed by photoemission

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    CeTe3 is a layered compound where an incommensurate Charge Density Wave (CDW) opens a large gap (400 meV) in optimally nested regions of the Fermi Surface (FS), whereas other sections with poorer nesting remain ungapped. Through Angle-Resolved Photoemission, we identify bands backfolded according to the CDW periodicity. They define FS pockets formed by the intersection of the original FS and its CDW replica. Such pockets illustrate very directly the role of nesting in the CDW formation but they could not be detected so far in a CDW system. We address the reasons for the weak intensity of the folded bands, by comparing different foldings coexisting in CeTe3

    Design of an integrated sub-6 ghz and mmwave mimo antenna for 5g handheld devices

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    The reported work demonstrates the design and realization of an integrated mid-band (sub-6 GHz) and mmWave multiple input, multiple output (MIMO) antenna for 5G handheld devices. The proposed prototype consists of the two-port MIMO configuration of the mid-band antenna placed at the top and bottom of the substrate, while the 4-port mmWave MIMO antenna is placed sideways. The MIMO configuration at the top and bottom consists of a two-element array to achieve high gain at the mid-band spectrum, while the antennas placed sideways are optimized to cover the 5G-mmWave band spectrum. The overall dimensions of the board were selected the same as the of smartphones, i.e., 151 mm x 72 mm. The mid-band antenna has an operational bandwidth of 2.73 GHz, whereas the mmWave antenna has an impedance bandwidth of 3.85 GHz with a peak gain of 5.29 and 8.57 dBi, respectively. Furthermore, the design is analyzed for the various MIMO performance parameters; it was found that the proposed antennas offer high performance in terms of envelop correlation coefficient (ECC), diversity gain (DG), mean effective gain (MEG) and channel capacity loss (CCL) within operational range. A fabricated prototype was tested and measured results show strong agreement with predicted results. Moreover, the proposed work is compared with state-of-the-art work for the same applications to demonstrate its potential for targeted application

    A Meta-Analysis on the Effects of Hydroxychloroquine on COVID-19.

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    Introduction Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread throughout the world with a large medical and economic impact. On March 12, 2020, the World Health Organization (WHO) classified SARS-CoV-2 as a pandemic. As a result of this worldwide public health crisis, politicians, elected officials, and healthcare professionals emergently began trialing hydroxychloroquine (HCQ) in efforts to treat and prevent the transmission of the virus. This meta-analysis was performed to assess the effects of HCQ on patients with COVID-19. Methods This meta-analysis adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRIMA) guidelines. Selected articles published between December 2019 and July 2020 were found utilizing the following search engines: PubMed, Google Scholar, Cochrane Library, DisasterLit, Clinicaltrials.gov, Medrxiv, and Embase. Two independent physician reviewers screened eligible articles that met the inclusion and exclusion criteria of the analysis. The outcome measures analyzed were mortality rate, rate of disease progression/improvement, rate of disease severity, and adverse effects of treatment. Six out of 14 studies that met the study\u27s eligibility criteria were selected and further analyzed, with a total of 381 participants (n= 381). Conclusion From the studies analyzed, it was found that groups treated with HCQ had an overall mortality rate that was 2.5 times greater than that of the control group. HCQ treated patients had higher rates of adverse clinical outcomes and side effects compared with the control populations. Lastly, there was a 1.2 times higher rate of improvement in the group of HCQ treated patients with mild to moderate symptoms as compared to the control group

    Finding Home Catalogue

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    Our stories are lifelines, traveling with us, tossed between continents, hidden, preserved, pulled out when needed. They are narratives told at refugee hearings, poems written long past midnight, films emerging from long pandemic days, phrases wrought from the scars of exile, the joys of freedom. This catalogue documents our research project Finding Home and the outcomes
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