2,463 research outputs found

    Quantum vortex lattice via Lifshitz duality

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    We study an effective field theory of a vortex lattice in a two-dimensional neutral rotating superfluid. Utilizing particle-vortex dualities we explore its formulation in terms of a U(1)U(1) gauge theory coupled to elasticity, that at low energies reduces to a Lifshitz theory augmented with a Berry phase term encoding the vortex dynamics in the presence of a superflow. Utilizing elasticity- and Lifshitz-gauge theory dualities, we derive dual formulations of the vortex lattice in terms of a traceless symmetric scalar-charge theory and demonstrate low-energy equivalence of our dual gauge theory to its elasticity-gauge theory dual. We further discuss a multipole symmetry of the vortex lattice and its dual gauge theory's multipole one-form symmetries. We also study its topological crystalline defects, where the multipole one-form symmetry plays a prominent role, organizing the defects, explaining their restricted mobility, and characterizing descendant vortex phases.Comment: 17 page

    The association between physical activity and the risk of symptomatic Barrettā€™s oesophagus: a UK prospective cohort study

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    Background: Physical activity affects the functioning of the gastrointestinal system through both local and systemic effects and may play an important role in the aetiology of gastroesophageal reflux disease, Barrettā€™s oesophagus and oesophageal adenocarcinoma. We investigated, for the first time in a large prospective cohort study, associations between recreational and occupational levels of physical activity and the incidence of Barrettā€™s oesophagus. Participants and methods: The European Prospective Investigation of Cancer-Norfolk recruited 30ā€‰445 men and women between 1993 and 1997. Occupational and recreational levels of physical activity were measured using a baseline questionnaire. The cohort was followed up until 2015 to identify symptomatic cases of Barrettā€™s oesophagus. Cox proportional hazard regression estimated hazard ratios (HR) for physical activity and the development of disease. Results: Two hundred and three participants developed Barrettā€™s oesophagus (mean age: 70.6 years) the majority of whom were men (70.9%). There was an inverse association between standing occupations and disease risk [HR: 0.50, 95% confidence interval (CI): 0.31ā€“0.82, P=0.006] when compared with sedentary jobs. Heavy manual occupations were positively associated with disease risk (HR: 1.66, 95% CI: 0.91ā€“3.00), but conventional statistical significance was not reached (P=0.09). No associations were found between recreational activity and the risk of Barrettā€™s oesophagus (HR: 1.34, 95% CI: 0.72ā€“2.50, P=0.35, highest vs. lowest levels of activity). Conclusion: Our study suggests that occupational levels of physical activity may be associated with the risk Barrettā€™s oesophagus. However, further work is required to confirm and describe specific occupations that may be protective

    The association between preoperative cardiopulmonary exercise test variables and short-term morbidity following oesophagectomy: A hospital-based cohort study

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    Background: Postoperative complications after esophagectomy are thought to be associated with reduced fitness. This observational study explored the associations between aerobic fitness, as determined objectively by preoperative cardiopulmonary exercise testing (CPEX), and 30-day morbidity after esophagectomy. Methods: We retrospectively identified 254 consecutive patients who underwent esophagectomy at a single academic teaching hospital between September 2011 and March 2017. Postoperative complication data were measured using the Esophageal Complications Consensus Group definitions and graded using the Clavien-Dindo classification system of severity (blinded to cardiopulmonary exercise testing values). Associations between preoperative cardiopulmonary exercise testing variables and postoperative outcomes were estimated using logistic regression. Results: A total of 206 patients (77% male) were included in the analyses, with a mean age of 67 years (SD 9). The mean values for the maximal oxygen consumed at the peak of exercise (VO 2peak) and the anaerobic threshold were 21.1 mL/kg/min (SD 4.5) and 12.4 mL/kg/min (SD 2.8), respectively. The vast majority of patients (98.5%) had malignant diseaseā€”predominantly adenocarcinoma (84.5%), for which most received neoadjuvant chemotherapy (79%) and underwent minimally invasive Ivor Lewis esophagectomy (53%). Complications at postoperative day 30 occurred in 111 patients (54%), the majority of which were cardiopulmonary (72%). No associations were found between preoperative cardiopulmonary exercise testing variables and morbidity for either VO 2peak (OR 1.00, 95% CI 0.94ā€“1.07) or anaerobic threshold (OR 0.98, 95% CI 0.89ā€“1.09). Conclusion: Preoperative cardiopulmonary exercise testing variables were not associated with 30-day complications after esophagectomy. The findings do not support the use of cardiopulmonary exercise testing as an isolated preoperative screening tool to predict short-term morbidity after esophagectomy. This modestly sized observational work highlights the need for larger studies examining associations between preoperative cardiopulmonary exercise testing and outcomes after esophagectomy to look for consistency in our findings

    CHD5 is down-regulated through promoter hypermethylation in gastric cancer

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    <p>Abstract</p> <p>Background</p> <p>Nonhistone chromosomal proteins in concert with histones play important roles in the replication and repair of DNA and in the regulation of gene expression. The deregulation of these proteins can contribute to the development of a variety of diseases such as cancer. As a nonhistone chromosomal protein, chromodomain helicase DNA binding protein 5 (CHD5) has recently been identified as the product of a novel tumor suppressor gene (TSG), promoting the transcription of p19<sup><it>ink4a </it></sup>and p16<sup><it>arf</it></sup>. The inactivation of CHD5 was achieved partly through genetic deletion since it is located in 1p36, a region frequently deleted in human tumors. In this study, we aim to study the involvement of CHD5 in gastric cancer, the second most common cancer worldwide.</p> <p>Methods</p> <p>CHD5 expression in a panel of gastric cancer cells were determined by quantitative RT-PCR. The methylation of CHD5 was evaluated by methylation specific PCR and bisulfite genome sequencing. The effect of CHD5 on growth of gastric cancer cells was tested by colony formation assay.</p> <p>Results</p> <p>CHD5 expression was down-regulated in all of gastric cancer cell lines used (100%, 7/7) and significantly restored after pharmacological demethylation. Methylation of CHD5 promoter was detected in all of seven gastric cancer cell lines and in the majority of primary gastric carcinoma tissues examined (73%, 11/15). Finally, ectopic expression of CHD5 in gastric cancer cells led to a significant growth inhibition.</p> <p>Conclusion</p> <p>CHD5 was a TSG epigenetically down-regulated in gastric cancer.</p

    Algebraic tools for the study of quaternionic behavioral systems

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    In this paper we study behavioral systems whose trajectories are given as solutions of quaternionic difference equations. As happens in the commutative case, it turns out that quaternionic polynomial matrices play an important role in this context. Therefore we pay special attention to such matrices and derive new results concerning their Smith form. Based on these results, we obtain a characterization of system theoretic properties such as controllability and stability of a quaternionic behavior

    Single nucleotide polymorphisms and post-operative complications following major gastrointestinal surgery: A systematic review and meta-analysis

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    Background: The human genome is an under-researched area of pre-operative risk stratification. Studies of genetic polymorphisms and their associations with acute post-operative complications in gastrointestinal surgery have reported statistically significant results, but have varied in methodology, genetic variations studied, and conclusions reached. To provide clarity, we conducted a systematic review and meta-analysis of single nucleotide polymorphisms and their association with post-operative complications after major gastro-8 intestinal surgery. Methods: We performed a literature search using Ovid MEDLINE and Web of Science databases. Studies were included if they investigated genetic polymorphisms and their associations with post-operative complications after major gastrointestinal surgery. We extracted clinical and genetic data from each paper and assessed for quality against the STrengthening the REporting of Genetic Association Studies (STREGA) guidelines. Odds ratios were presented, with 95% confidence intervals, to assess strengths of association. We conducted a meta-analysis on TNF-alpha-308, which had been assessed in three papers. Results: Our search returned 68 papers, of which 5 were included after screening and full-text review. Twenty-two different single nucleotide polymorphisms (SNPs) were investigated in these studies. We found that all papers were genetic association studies, and had selected SNPs related to inflammation. The outcome investigated was most commonly post-operative infection, but also anastomotic leak and other non-infectious complications. Statistically significant associations were found for: TNF-alpha-308, IL-10-819, PTGS2-765 and IFN-gamma-874. There was significant variability in study quality and methodology. We conducted a meta-analysis on associations between the TNF-alpha-308 polymorphism and post-operative infection and report an OR of 1.18 (CI 0.27 ā€“ 5.21). Conclusions: We found biologically plausible associations between SNPs involved in inflammation and post-operative infection, but the available data were too limited and of insufficient quality to reach definitive conclusions. Further work is needed, including genome-wide association studies (GWAS)

    Potential Uses of Wild Germplasms of Grain Legumes for Crop Improvement

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    Challenged by population increase, climatic change, and soil deterioration, crop improvement is always a priority in securing food supplies. Although the production of grain legumes is in general lower than that of cereals, the nutritional value of grain legumes make them important components of food security. Nevertheless, limited by severe genetic bottlenecks during domestication and human selection, grain legumes, like other crops, have suffered from a loss of genetic diversity which is essential for providing genetic materials for crop improvement programs. Illustrated by whole-genome-sequencing, wild relatives of crops adapted to various environments were shown to maintain high genetic diversity. In this review, we focused on nine important grain legumes (soybean, peanut, pea, chickpea, common bean, lentil, cowpea, lupin, and pigeonpea) to discuss the potential uses of their wild relatives as genetic resources for crop breeding and improvement, and summarized the various genetic/genomic approaches adopted for these purposes.Instituto de FisiologĆ­a y Recursos GenĆ©ticos VegetalesFil: MuƱoz, Nacira Belen. Chinese University of Hong Kong. Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology and School of Life Sciences; China. Instituto Nacional de TecnologĆ­a Agropecuaria (INTA). Instituto de FisiologĆ­a y Recursos GenĆ©ticos Vegetales; Argentina. Universidad Nacional de CĆ³rdoba. Facultad de Ciencias Exactas FĆ­sicas y Naturales. CĆ”tedra de FisiologĆ­a Vegetal; ArgentinaFil: Ailin, Liu. Chinese University of Hong Kong. Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology and School of Life Sciences; ChinaFil: Leo, Kan. Chinese University of Hong Kong. Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology and School of Life Sciences; ChinaFil: Man-Wah, Li. Chinese University of Hong Kong. Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology and School of Life Sciences; ChinaFil: Hon-Ming, Lam. Chinese University of Hong Kong. Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology and School of Life Sciences; Chin

    The management of municipal solid waste in Hong Kong : a study of civic engagement strategies

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    published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

    The Feasibility of Integrating the Noble Scallop Mimachlamys nobilis with Existing Fish Monoculture Farms in the South China Sea: A Bioeconomic Assessment from Hong Kong

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    The environmental implications of integrated multitrophic aquaculture have been well studied in China, but few investigations have empirically explored potential economic benefits. This study investigated the technical and economic feasibility of physically integrating the noble scallop Mimachlamys nobilis (Reeve, 1852) with existing fish monoculture farms in Hong Kong. Scallops were grown for 201 days from June to December in lantern nets hung directly from fish farm platforms at treatment depths of 1, 3.5, and 6 m. Only the 1-m treatment attained the target mean height-at-harvest of 80 mm. Fitted von Bertalanffy growth functions showed significant differences in growth performance between depths. The von Bertalanffy growth function projected that the 3.5- and 6-m treatments would require an additional 26 and 59 days of culture to reach 80 mm. Mortality was significantly lower at 1 m (53% Ā± 12.5%) compared with those at 3.5 m (70% Ā± 9.0%) and 6 m (83% Ā± 4.5%). The slower growth and higher mortality at 3.5 and 6mwere probably due to periodically low oxygen which dropped to 4.96, 3.08, and 1.73 mg L-1 at 1, 3.5, and 6 m, respectively, in midsummer. A bioeconomic assessments of two typical farm sizes was conducted; small (45 m2) and large (315 m2). The initial investment, discounted payback time, and 10-y net present value of the projects was US5,485.51,3y,andUS5,485.51, 3 y, and US20,211.33, respectively, for the small farm and US27,659.03,2y,andUS27,659.03, 2 y, and US227,406.49, respectively, for the large farm. Sensitivity analysis revealed that the profitability of operations was sensitive to changes in mortality and sales price. This study has confirmed that physically integrating M. nobilis at existing fish farms is technically and economically feasible
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