6,830 research outputs found

    Four conjectures in Nonlinear Analysis

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    In this chapter, I formulate four challenging conjectures in Nonlinear Analysis. More precisely: a conjecture on the Monge-Amp\`ere equation; a conjecture on an eigenvalue problem; a conjecture on a non-local problem; a conjecture on disconnectedness versus infinitely many solutions.Comment: arXiv admin note: text overlap with arXiv:1504.01010, arXiv:1409.5919, arXiv:1612.0819

    Specific inhibition of cyclooxygenase-2 down-regulates NF-kappaB activation in gastric cancer cells by blocking its nuclear translocation

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    Loss of heterozygosity in multistage carcinogenesis of esophageal carcinoma at high-incidence area in Henan Province, China

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    Aim: Microsatellites are the repeated DNA sequences scattered widely within the genomes and closely linked with many important genes. This study was designed to characterize the changes of microsatellite DNA loss of heterozygosity (LOH) in esophageal carcinogenesis. Methods: Allelic deletions in 32 cases of matched precancerous, cancerous and normal tissues were examined by syringe microdissection under an anatomic microscope and microsatellite polymorphism analysis using 15 polymorphic markers on chromosomes 3p, 5q, 6p, 9p, 13q, 17p, 17q and 18q. Results: Microsatellite DNA LOH was observed in precancerous and cancerous tissues, except D9S1752. The rate of LOH increased remarkably with the lesions progressed from basal cell hyperplasia (BCH) to squamous cell carcinoma (SCC) (P60%). LOH loci were different in precancerous and cancerous tissues. LOH in D3S1234 and TP53 was the common event in different lesions from the same patients. Conclusion: Microsatellite DNA LOH occurs in early stage of human esophageal carcinogenesis, even in BCH. With the lesion progressed, gene instability increases, the accumulation of this change may be one of the important mechanisms driving precancerous lesions to cancer. Ā© 2005 The WJG Press and Elsevier Inc. All rights reserved.published_or_final_versio

    How do weather and climate change impact the COVID-19 pandemic? Evidence from the Chinese mainland

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    The COVID-19 pandemic continues to expand, while the relationship between weather conditions and the spread of the virus remains largely debatable. In this paper, we attempt to examine this question by employing a flexible econometric model coupled with fine-scaled hourly temperature variations and a rich set of covariates for 291 cities in the Chinese mainland. More importantly, we combine the baseline estimates with climate-change projections from 21 global climate models to understand the pandemic in different scenarios. We found a significant negative relationship between temperatures and caseload. A one-hour increase in temperatures from 25 Ā°C to 28 Ā°C tends to reduce daily cases by 15.1%, relative to such an increase from āˆ’2 Ā°C to 1 Ā°C. Our results also suggest an inverted U-shaped nonlinear relationship between relative humidity and confirmed cases. Despite the negative effects of heat, we found that rising temperatures induced by climate change are unlikely to contain a hypothesized pandemic in the future. In contrast, cases would tend to increase by 10.9% from 2040 to 2059 with a representative concentration pathway (RCP) of 4.5 and by 7.5% at an RCP of 8.5, relative to 2020, though reductions of 1.8% and 18.9% were projected for 2080ā€“2099 for the same RCPs, respectively. These findings raise concerns that the pandemic could worsen under the climate-change framework

    Rationale and protocol of the Dapagliflozin And Prevention of Adverse outcomes in Chronic Kidney Disease (DAPA-CKD) randomized controlled trial.

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    BACKGROUND: Recent cardiovascular outcome trials have shown that sodium-glucose co-transporter 2 (SGLT2) inhibitors slow the progression of chronic kidney disease (CKD) in patients with type 2 diabetes at high cardiovascular risk. Whether these benefits extend to CKD patients without type 2 diabetes or cardiovascular disease is unknown. The Dapagliflozin and Prevention of Adverse Outcomes in CKD (DAPA-CKD) trial (NCT03036150) will assess the effect of the SGLT2 inhibitor dapagliflozin on renal and cardiovascular events in a broad range of patients with CKD with and without diabetes. METHODS: DAPA-CKD is a randomized, double-blind, placebo-controlled, trial in which āˆ¼4300 patients with CKD Stages 2-4 and elevated urinary albumin excretion will be enrolled. The vast majority will be receiving a maximum tolerated dose of a renin-angiotensin system inhibitor at enrolment. RESULTS: After a screening assessment, eligible patients with a urinary albumin:creatinine ratio ā‰„200ā€‰mg/g and estimated glomerular filtration rate (eGFR) between 25 and 75ā€‰mL/min/1.73ā€‰m2 are randomly assigned to placebo or dapagliflozin 10ā€‰mg/day. Enrolment is monitored to ensure that at least 30% of patients do not have diabetes and that no more than 10% have an eGFR >60ā€‰mL/min/1.73ā€‰m2. The primary endpoint is a composite of a sustained decline in eGFR of ā‰„50%, end-stage renal disease, renal death or cardiovascular death. The trial will conclude when 681 primary renal events have occurred, providing 90% power to detect a 22% relative risk reduction (Ī± level of 0.05). CONCLUSION: DAPA-CKD will determine whether the SGLT2 inhibitor dapagliflozin, added to guideline-recommended therapies, safely reduces the rate of renal and cardiovascular events in patients across multiple CKD stages with and without diabetes

    Direct Formation of Supermassive Black Holes via Multi-Scale Gas Inflows in Galaxy Mergers

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    Observations of distant bright quasars suggest that billion solar mass supermassive black holes (SMBHs) were already in place less than a billion years after the Big Bang. Models in which light black hole seeds form by the collapse of primordial metal-free stars cannot explain their rapid appearance due to inefficient gas accretion. Alternatively, these black holes may form by direct collapse of gas at the center of protogalaxies. However, this requires metal-free gas that does not cool efficiently and thus is not turned into stars, in contrast with the rapid metal enrichment of protogalaxies. Here we use a numerical simulation to show that mergers between massive protogalaxies naturally produce the required central gas accumulation with no need to suppress star formation. Merger-driven gas inflows produce an unstable, massive nuclear gas disk. Within the disk a second gas inflow accumulates more than 100 million solar masses of gas in a sub-parsec scale cloud in one hundred thousand years. The cloud undergoes gravitational collapse, which eventually leads to the formation of a massive black hole. The black hole can grow to a billion solar masses in less than a billion years by accreting gas from the surrounding disk.Comment: 26 pages, 4 Figures, submitted to Nature (includes Supplementary Information

    SmartEx: a case study on user profiling and adaptation in exhibition booths

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    An investigation into user profiling and adaptation with exhibition booth as a case study is reported. First a review of the field of exhibitions and trade fairs and a summary introduction to adaptation and profiling are given. We then introduce three criteria for the evaluation of exhibition booth: effectiveness, efficiency and affect. Effectiveness is related the amount of information collected, efficiency is a measurement of the time taken to collect the information, and affect is the perception of the experience and the mood booth visitors have during and after their visit. We have selected these criteria to assess adaptive and profiled exhibition booths, we call smart exhibition (SmartEx). The assessment is performed with an experiment with three test conditions (non-profiled/non adaptive, profiled/non-adaptive and profiled adaptive presentations). Results of the experiment are presented along discussion. While there is significant improvements of effectiveness and efficiency between the two-first test conditions, the improvement is not significant for the last test condition, for reasons explained. As for the affect, the results show that it has an under-estimated importance in people minds and that it should be addressed more carefully

    Static non-reciprocity in mechanical metamaterials

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    Reciprocity is a fundamental principle governing various physical systems, which ensures that the transfer function between any two points in space is identical, regardless of geometrical or material asymmetries. Breaking this transmission symmetry offers enhanced control over signal transport, isolation and source protection. So far, devices that break reciprocity have been mostly considered in dynamic systems, for electromagnetic, acoustic and mechanical wave propagation associated with spatio-temporal variations. Here we show that it is possible to strongly break reciprocity in static systems, realizing mechanical metamaterials that, by combining large nonlinearities with suitable geometrical asymmetries, and possibly topological features, exhibit vastly different output displacements under excitation from different sides, as well as one-way displacement amplification. In addition to extending non-reciprocity and isolation to statics, our work sheds new light on the understanding of energy propagation in non-linear materials with asymmetric crystalline structures and topological properties, opening avenues for energy absorption, conversion and harvesting, soft robotics, prosthetics and optomechanics.Comment: 19 pages, 3 figures, Supplementary information (11 pages and 5 figures

    Higgs Boson Mass in Low Scale Gauge Mediation Models

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    We consider low scale gauge mediation models with a very light gravitino m_{3/2}~16 eV, in the light of recent experimental hints on the Higgs boson mass. The light gravitino is very interesting since there is no gravitino over-production problem, but it seems difficult to explain the Higgs boson mass of ~125 GeV. This is because of the conflict between the light gravitino mass and heavy SUSY particle masses needed for producing the relatively heavy Higgs boson mass. We consider two possible extensions in this paper: a singlet extension of the Higgs sector, and strongly coupled gauge mediation. We show that there is a large parameter space, in both scenarios, where the Higgs boson mass of ~125 GeV is explained without any conflict with such a very light gravitino.Comment: 23 pages, 5 figure
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