2,406 research outputs found

    Class of variational AnsÀtze for the spin-incoherent ground state of a Luttinger liquid coupled to a spin bath

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    Interacting one-dimensional electron systems are generally referred to as “Luttinger liquids”, after the effective low-energy theory in which spin and charge behave as separate degrees of freedom with independent energy scales. The “spin-incoherent Luttinger liquid” describes a finite-temperature regime that is realized when the temperature is very small relative to the Fermi energy, but larger than the characteristic spin energy scale. Similar physics can take place in the ground-state, when a Luttinger Liquid is coupled to a spin bath, which effectively introduces a “spin temperature”through its entanglement with the spin degree of freedom. We show that the spin-incoherent state can be exactly written as a factorized wave-function, with a spin wave-function that can be described within a valence bond formalism. This enables us to calculate exact expressions for the momentum distribution function and the entanglement entropy. This picture holds not only for two antiferromagnetically coupled t−J chains, but also for the t−J-Kondo chain with strongly interacting conduction electrons. We argue that this theory is quite universal and may describe a family of problems that could be dubbed “spin-incoherent”.Accepted manuscrip

    Spectral function of the U→∞U \rightarrow \infty one dimensional Hubbard model at finite temperature and the crossover to the spin incoherent regime

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    The physics of the strongly interacting Hubbard chain (with t/Uâ‰Ș1t/U \ll 1) at finite temperatures undergoes a crossover to a spin incoherent regime when the temperature is very small relative to the Fermi energy, but larger than the characteristic spin energy scale. This crossover can be understood by means of Ogata and Shiba's factorized wave function, where charge and spin are totally decoupled, and assuming that the charge remains in the ground state, while the spin is thermally excited and at an effective "spin temperature". We use the time-dependent density matrix renormalization group method (tDMRG) to calculate the dynamical contributions of the spin, to reconstruct the single-particle spectral function of the electrons. The crossover is characterized by a redistribution of spectral weight both in frequency and momentum, with an apparent shift by kFk_F of the minimum of the dispersion.Comment: 4+pages, 3 fig

    P-selectin in preterm infants suffering necrotizing enterocolitis

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    Background: Platelet selectin (P-selectin), an adhesion molecule expressed by activated endothelial cells, mediates the early phases of leukocyte adherence to the endothelium. Expression of P-selectin has been shown to be crucial to neutrophil recruitment in many human inflammatory processes as well as in animal models of intestinal ischemia-reperfusion, intestinal transplantation, and sepsis, but its role in NEC is unknown. Objective: To study P-selectin, a possible cause of NEC, in the blood of preterm infants. Study design: Twenty-four consecutive preterms, clinically suspected or proven to have NEC, were enrolled in this pilot study. Their weight ranged from 1 to 2.3 Kg (mean ±SD: 1.7±0.5 Kg), age ranged from 2 to 21 days (mean ±SD: 12±3.5 days) and their gestational age (GA) ranged from 29 to 33 weeks (mean ±SD: 31±3 weeks). In addition, 12 age- and weight-matched apparently healthy preterm infants served as a control group. Written consents were obtained from the parents of infants included in the study. All neonates were subjected to perinatal history, clinical examination, routine investigations (CBC, plain X-ray and abdominal ultrasonography (US), arterial blood gases and serum bicarbonate, serum sodium, CRP and blood culture), and measurement of blood P-selectin by direct immunofluorescent staining. Results: Infants with NEC clinically presented with significant PROM, gastric residual, abdominal distensions, hypoperfusion, hematochezia and evidence of NEC in abdominal X-ray and/or US, compared to control infants. Significant abnormal laboratory investigations in NEC cases included high CRP, hyponatremia, bandemia, thrombocytopenia, metabolic acidosis, and blood culture-proven neonatal sepsis. Abnormal blood P-selectin (>20 units) was detected in 21 (87.5%) infants with NEC, with a mean level of 51±12.4 units that was significantly higher than that of control infants, P < 0.001. A strong significant negative correlation was observed between blood P-selectin and each of GA, body weight, platelet count, arterial blood pH and bicarbonate, while it was a significant positive correlation with each of CRP and band cell count. Conclusion: P-selectin may have a role in the pathogenesis of NEC in preterm infants and may be used as a diagnostic tool. Keywords: Prematurity -abdominal distension-hematocheziaEgypt J Pediatr Allergy Immunol 2010;8(2):61-6

    Efficiency of Dimethyl Sulphoxide and Ethylene Glycol on Subsequent Development of Vitrified Awassi Sheep Embryos

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    The use of cryoprotectants in vitrification would reduce the critical damages to the embryos, thus increase the survival rates. This research was conducted in the laboratory of reproductive biotechnology at the faculty of Agriculture of Aleppo University.  The study aimed to evaluate the viability and survivability of early Syrian Awassi embryos under the influence of dimethyl sulphoxide (DMSO) and ethylene glycol (EG) following vitrification. Embryos were vitrified in three solutions of cryoprotectants (A: DMSO (3 ml), B: EG (3 ml), and C which was composed of a combination of DMSO (1.5 ml) and EG (1.5 ml)). After thawing, embryos that had been vitrified in C solution achieved the highest rates of cleavage (P 0.01) comparing with A and B solutions for 2-16 cell stage (50.00% Vs 30.77% and 36.36%), morula (9.00% Vs 44.44% and 40.00%) and blastocyst stage embryos (92.86% Vs 58.33% and 50.00%) respectively. Down to the hatching blastocyst stage, 2-16 cell stage vitrified embryos in C solution achieved an encouraging rate comparing with A and B solutions (39.20% Vs23.08% and 22.73% respectively). The rates of arrested embryos decreased significantly (P 0.05) after thawing across the three solutions especially the morula and blastocyst stage (0.00 and 3.70% respectively) (C solution). No significant differences were observed in the three types of embryos across all stages and solutions despite the large range among these rates. Given the apparent benefit of the participatory effect of cytoprotectants, it is advised to use a mixture of DMSO and EG (1:1) in vitrification of ovine embryos

    Pick the Right Tactics When Online Sales Go Live: An Empirical Analysis of Livestreaming for Amazon Sellers

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    Using livestreaming to boost sales has become an essential strategy to achieve deeper interactions with customers for many large e-commerce platforms worldwide. Existing livestreaming literature has looked at multiple Chinese e-commerce platforms but not enough attention has been paid to the U.S. market. This study investigates consumer behaviors and the promotion efficacy in the Livestream setting on Amazon Live. We analyze the time patterns of customer engagement and explain why sellers should use different promotion strategies for weekdays and for weekend streamers. Besides, we present evidence that the average video display time per product is crucial for the livestream promotion efficacy and suggest optimal time-exposure intervals as a benchmark for sellers to align with

    Chelatococcus thermostellatus sp. nov., a new thermophile for bioplastic synthesis: comparative phylogenetic and physiological study

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    The poly(3-hydroxybutyrate), PHB, accumulating thermophilic strain MW9(T), isolated from an aerobic organic waste treatment plant, was characterized by detailed physiological and phylogenetic studies. The strain is a Gram-stainnegative, rod shaped, non-spore forming member of Alphaproteobacteria. It shows optimum growth at 50 degrees C. Based on 16S rRNA gene sequence similarity, the strain together with five very similar isolates, was affiliated to the genus Chelatococcus (Ibrahim et al. in J Appl Microbiol 109: 1579-1590, 2010). Rep-PCR genomic fingerprints and partial dnaK gene sequence also revealed that these isolates are very similar, but differ from other Chelatococcus type strains. The major fatty acids were similar to those of other strains of the genus Chelatococcus. DNA-DNA hybridization of strain MW9(T) with Chelatococcus species type strains revealed 11.0-47.7 % relatedness. G+C content of DNA was 67.1 mol%, which is comparable with the other strains of Chelatococcus species. The physiological and phenotypic characteristics of the new strain MW9(T) are sufficient to differentiate it from previously described species in the genus Chelatococcus. Strain MW9(T) is considered to represent a novel species of the genus Chelatococcus, for which the name Chelatococcus thermostellatus is proposed. The type strain is MW9(T) (= LMG 27009(T) = DSM 28244(T)). Compared to known Chelatococcus strains, strain MW9(T) could be a potent candidate for bioplastic production at elevated temperature

    Pan-cancer classifications of tumor histological images using deep learning

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    Histopathological images are essential for the diagnosis of cancer type and selection of optimal treatment. However, the current clinical process of manual inspection of images is time consuming and prone to intra- and inter-observer variability. Here we show that key aspects of cancer image analysis can be performed by deep convolutional neural networks (CNNs) across a wide spectrum of cancer types. In particular, we implement CNN architectures based on Google Inception v3 transfer learning to analyze 27815 H&E slides from 23 cohorts in The Cancer Genome Atlas in studies of tumor/normal status, cancer subtype, and mutation status. For 19 solid cancer types we are able to classify tumor/normal status of whole slide images with extremely high AUCs (0.995±0.008). We are also able to classify cancer subtypes within 10 tissue types with AUC values well above random expectations (micro-average 0.87±0.1). We then perform a cross-classification analysis of tumor/normal status across tumor types. We find that classifiers trained on one type are often effective in distinguishing tumor from normal in other cancer types, with the relationships among classifiers matching known cancer tissue relationships. For the more challenging problem of mutational status, we are able to classify TP53 mutations in three cancer types with AUCs from 0.65-0.80 using a fully-trained CNN, and with similar cross-classification accuracy across tissues. These studies demonstrate the power of CNNs for not only classifying histopathological images in diverse cancer types, but also for revealing shared biology between tumors. We have made software available at: https://github.com/javadnoorb/HistCNNFirst author draf

    Synthesis and comparative studies of phase transition behaviour of new dimeric liquid crystals consisting of dimethyluracil and biphenyl cores

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    A new homologous series of mesogens containing 6-amino-1,3-dimethyluracil moiety have been synthesized. The structures of the compounds were characterised by elemental analysis, FT-IR, 1H and 13C NMR spectroscopic techniques. Their mesomorphic properties were studied by polarising optical microscopy attached to a heating stage. Microscopy data were supported with transition temperatures and enthalpy change values obtained from the differential scanning calorimetry analysis. The studies have shown that the mesomorphic properties of the compounds are dependent on the lengths of alkoxy-spacers. Compounds 4a-f with a shorter alkoxy-spacer chain (n = 6) exhibited smectic A phase, while compounds 4g-r with a alkoxy-spacer chain (n = 8 or 10) displayed nematic phase

    Sustainable supply chain management in stakeholders:supporting from sustainable supply and process management in the healthcare industry in Vietnam

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    © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group. Prior studies presented the sustainable supply chain management practices, but an approach from stakeholders is still untapped. The interaction between forward and reverse flows also needs to be involved in investment recovery. Sustainable supply chain management is an increasing concern in the environmental, social and economic performance. This study uses fuzzy Delphi method to validate a set of criteria and uses exploratory factor analysis to confirm the aspects. This study applies stakeholder theory in combination with fuzzy set theory and decision-making trial and evaluation method to explore the interrelationships among attributes. The results show that sustainable supply management and process management are the major cause aspects. Investment recovery has not been noticed in the healthcare industry, reflected in the weak interaction. The top five criteria are supplier assessment, environmental management systems, green certification of supplier, supplier collaboration and health and safety certifications. This study provides theoretical and managerial implications
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