1,234 research outputs found

    Risk of Covid-19 in shielded and nursing care home patients: cohort study in general practice

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    Background: Covid-19 cases were first detected in the UK in January 2020 and vulnerable patients were asked to shield from March to reduce their risk of Covid-19 infection. Aim: To determine the risk and determinants of Covid-19 diagnosis in shielded vs. non-shielded groups adjusted for key comorbidities not explained by shielding. Design: Retrospective cohort study of adults with COVID-19 infection between 1/2/20-15/5/20 in West London. Method: Individuals diagnosed with Covid-19 were identified in SystmOne records using clinical codes. Infection risks were adjusted for socio-demographic factors, nursing home status and comorbidities. Results: Of 57,713 adults, 573 (1%) individuals were identified as shielded and 1,074 adults had documented Covid-19 infections (1.9%). Covid-19 infection rate in the shielded group individuals compared with non-shielded adult individuals was 6.5 % (37/573) vs. 1.8 % (1,037/57, 140), p30kg/m2) 1.39 (1.18-1.63) p<0.001, and age 1.02 (1.01-1.02) p<0.001. Male gender was associated with lower risk of Covid-19 infection: 0.71 (0.62-0.82) p<0.001. Conclusion: Shielded individuals had a higher Covid-19 infection rate compared with non-shielded individuals, after adjusting for socio-demographic factors, nursing home status, and comorbidities

    Seed germination and seedling establishment of some wild almond species

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    Wild almond species are important genetic resources for resistance to unsuitable condition, especially drought stress. They have been used traditionally as rootstocks in some areas of Iran. So far, 21 wild almond species and 7 inter species hybrids have been identified in Iran. To study seed germination and seedling establishment of some of these species, three separate experiments were designed. In the first experiment, the application of gibberellic acid (GA3) (0, 250, 500 and 750 ppm) for 24 h was studied on germination characteristics of four wild almond accessions after stratification at 5 ± 0.5°C in Perlite media. Germination percentage, index vigor and root initiation factors were different in almond accessions, but were not affected by hormonal treatments. In the second experiment, seeds of another six wild almond accessions were stratified to compare their germination ability. Germination percentage, index vigor and root initiation were different among accessions significantly. In the last experiment, the establishment and vigor of 14 accessions from eight almond species have been evaluated in plastic bags in outdoor conditions. Two ecotypes of Prunus spp. had the highest stem diameter and length at all growing stages.Keywords: Amygdalus, germination percentage, index vigor, root initiation, stem length, stem diameter

    Activated biochars as sustainable and effective supports for hydrogenations

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    Activated biochars were obtained from pyrolysis and CO2-physical activation of four different biomasses including tannery shaving waste (T), vine wood waste (W), barley waste (B) and Sargassum, brown macroalgae of Venice lagoon (A). The potential of obtained carbonaceous materials as the supports of Ni,Al catalysts was investigated in levulinic acid (LA) conversion to Îł-valerolactone (GVL) as a model hydrogenation reaction. Al-containing species as the Lewis acid sites for the dehydration step were incorporated to the supports using wet impregnation or precipitation. Ni as a hydrogenation active phase was added to the supports via wet impregnation. Biochar-based supports and catalysts were characterized by AAS, elemental analysis, FTIR, N2 physisorption, XRD, SEM, EDS, TEM, He-TPD, NH3-TPD and TPR techniques. The catalysts were tested for LA hydrogenation to GVL in a batch system and aqueous medium. The results showed that Ni supported on activated biochar was not active due to a lack of Lewis acid sites for dehydration. Precipitated Al-containing species on the biochar-based supports demonstrated a better catalytic performance in the reaction compared to impregnated one because of different interactions with the support and Ni species. Among different supports, the activated biochars obtained from T and W acted as the best ones. A higher catalytic efficiency was strongly influenced by the chemical (aromaticity and stability, presence of N,O-doped and functional groups), textural (the porous texture and surface area), and morphological (higher dispersion of active phases) properties of activated biochars obtained from different biomasses with different natures

    New constraints for QCD matter from improved Bayesian parameter estimation in heavy-ion collisions at LHC

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    The transport properties of quark-gluon plasma created in relativistic heavy-ion collisions are quantified by an improved global Bayesian analysis using the CERN Large Hadron Collider Pb-Pb data at root s(NN) = 2.76 and 5.02 TeV. The results show that the uncertainty of the extracted transport coefficients is significantly reduced by including new sophisticated collective flow observables from two collision energies for the first time. This work reveals the stronger temperature dependence of specific shear viscosity, a lower value of specific bulk viscosity, and a higher hadronization switching temperature than in the previous studies. The sensitivity analysis confirms that the precision measurements of higher-order harmonic flow and their correlations are crucial in extracting accurate values of the transport properties. (C) 2022 The Author(s). Published by Elsevier B.V.Peer reviewe

    MCM-41 supported co-based bimetallic catalysts for aqueous phase transformation of glucose to biochemicals

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    The transformation of glucose into valuable biochemicals was carried out on different MCM-41-supported metallic and bimetallic (Co, Co-Fe, Co-Mn, Co-Mo) catalysts and under different reaction conditions (150 °C, 3 h; 200 °C, 0.5 h; 250 °C, 0.5 h). All catalysts were characterized using N2 physisorption, Temperature Programmed Reduction (TPR), Raman, X-ray Diffraction (XRD) and Temperature Programmed Desorption (TPD) techniques. According to the N2-physisorption results, a high surface area and mesoporous structure of the support were appropriate for metal dispersion, reactant diffusion and the formation of bioproducts. Reaction conditions, bimetals synergetic effects and the amount and strength of catalyst acid sites were the key factors affecting the catalytic activity and biochemical selectivity. Sever reaction conditions including high temperature and high catalyst acidity led to the formation mainly of solid humins. The NH3-TPD results demonstrated the alteration of acidity in different bimetallic catalysts. The 10Fe10CoSiO2 catalyst (MCM-41 supported 10 wt. þ, 10 wt. %Co) possessing weak acid sites displayed the best catalytic activity with the highest carbon balance and desired product selectivity in mild reaction condition. Valuable biochemicals such as fructose, levulinic acid, ethanol and hydroxyacetone were formed over this catalyst

    MCM-41 Supported Co-based Bimetallic Catalysts for Aqueous Phase Transformation of Glucose in Biochemicals

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    The transformation of glucose into valuable biochemicals was carried out on different MCM-41-supported metallic and bimetallic (Co, Co-Fe, Co-Mn, Co-Mo) catalysts and under different reaction conditions (150 °C, 3 h; 200 °C, 0.5 h; 250 °C, 0.5 h). All catalysts were characterized using N2 physisorption, Temperature Programmed Reduction (TPR), Raman, X-ray Diffraction (XRD) and Temperature Programmed Desorption (TPD) techniques. According to the N2-physisorption results, a high surface area and mesoporous structure of the support were appropriate for metal dispersion, reactant diffusion and the formation of bioproducts. Reaction conditions, bimetals synergetic effects and the amount and strength of catalyst acid sites were the key factors affecting the catalytic activity and biochemical selectivity. Sever reaction conditions including high temperature and high catalyst acidity led to the formation mainly of solid humins. The NH3-TPD results demonstrated the alteration of acidity in different bimetallic catalysts. The 10Fe10CoSiO2 catalyst (MCM-41 supported 10 wt.þ, 10 wt.%Co) possessing weak acid sites displayed the best catalytic activity with the highest carbon balance and desired product selectivity in mild reaction condition. Valuable biochemicals such as fructose, levulinic acid, ethanol and hydroxyacetone were formed over this catalyst

    Ingestion rate and feeding behavior of guppy (Poecilia reticulata Peters) larvae fed on nauplii of Artemia urmiana and Artemia franciscana

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    Artemia nauplii, despite their marine origin, have a good potential for application in the freshwater ornamental fish culture. In this study, two types of Artemia urmiana and Artemia franciscana were used for feeding of Guppy (Poecilia reticulata Peters) Larvae. Newly hatched fresh nauplii at three different densities of 3, 6, and 12 ind./ml as live feeds were compared for measuring larval ingestion rate. Results showed that type and density of Artemia nauplii had significant effects on ingestion rate (P<0.05). The average ingestion rate in larvae which maintain 12 hours starvation (first set of experiment) were 36, 244, and 664 ind./larvae/day for A. urmiana, correspondingly, for A. franciscana were 160, 480, and 880 ind./larvae/day at densities of 3, 6, and 12 ind./ml, respectively. The average ingestion rate of guppy larvae with 24, 48 and 72 hours feeding preconditions (2^nd, 3^rd and 4^th set of experiment) were significantly (P<0.05) decreased. After starvation, the ingestion rate of guppy larvae fed A. urmiana had range 22-54, 86-102, and 148-188 ind./larvae/day, correspondingly, for A. franciscana 66-100, 100-260, and 200-224 ind./larvae/day at 3, 6, and 12 ind./ml, respectively. The use of suitable densities of 6 and 12 ind./ml from Artemia nauplii could increase efficiency of utilization and also improve Guppy larvae production

    Generating GHZ state in 2m-qubit spin network

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    We consider a pure 2m-qubit initial state to evolve under a particular quantum me- chanical spin Hamiltonian, which can be written in terms of the adjacency matrix of the Johnson network J(2m;m). Then, by using some techniques such as spectral dis- tribution and stratification associated with the graphs, employed in [1, 2], a maximally entangled GHZ state is generated between the antipodes of the network. In fact, an explicit formula is given for the suitable coupling strengths of the hamiltonian, so that a maximally entangled state can be generated between antipodes of the network. By using some known multipartite entanglement measures, the amount of the entanglement of the final evolved state is calculated, and finally two examples of four qubit and six qubit states are considered in details.Comment: 22 page

    A general algorithm for manipulating non-linear and linear entanglement witnesses by using exact convex optimization

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    A generic algorithm is developed to reduce the problem of obtaining linear and nonlinear entanglement witnesses of a given quantum system, to convex optimization problem. This approach is completely general and can be applied for the entanglement detection of any N-partite quantum system. For this purpose, a map from convex space of separable density matrices to a convex region called feasible region is defined, where by using exact convex optimization method, the linear entanglement witnesses can be obtained from polygonal shape feasible regions, while for curved shape feasible regions, envelope of the family of linear entanglement witnesses can be considered as nonlinear entanglement witnesses. This method proposes a new methodological framework within which most of previous EWs can be studied. To conclude and in order to demonstrate the capability of the proposed approach, besides providing some nonlinear witnesses for entanglement detection of density matrices in unextendible product bases, W-states, and GHZ with W-states, some further examples of three qubits systems and their classification and entanglement detection are included. Also it is explained how one can manipulate most of the non-decomposable linear and nonlinear three qubits entanglement witnesses appearing in some of the papers published by us and other authors, by the method proposed in this paper. Keywords: non-linear and linear entanglement witnesses, convex optimization. PACS number(s): 03.67.Mn, 03.65.UdComment: 37 page
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