3,940 research outputs found

    Fraction Constraint in Partial Wave Analysis

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    To resolve the non-convex optimization problem in partial wave analysis, this paper introduces a novel approach that incorporates fraction constraints into the likelihood function. This method offers significant improvements in both the efficiency of pole searching and the reliability of resonance selection within partial wave analysis

    Event Generation and Consistence Test for Physics with Sliced Wasserstein Distance

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    In the field of modern high-energy physics research, there is a growing emphasis on utilizing deep learning techniques to optimize event simulation, thereby expanding the statistical sample size for more accurate physical analysis. Traditional simulation methods often encounter challenges when dealing with complex physical processes and high-dimensional data distributions, resulting in slow performance. To overcome these limitations, we propose a solution based on deep learning with the sliced Wasserstein distance as the loss function. Our method shows its ability on high precision and large-scale simulations, and demonstrates its effectiveness in handling complex physical processes. By employing an advanced transformer learning architecture, we initiate the learning process from a Monte Carlo sample, and generate high-dimensional data while preserving all original distribution features. The generated data samples have passed the consistence test, that is developed to calculate the confidence of the high-dimentional distributions of the generated data samples through permutation tests. This fast simulation strategy, enabled by deep learning, holds significant potential not only for increasing sample sizes and reducing statistical uncertainties but also for applications in numerical integration, which is crucial in partial wave analysis, high-precision sample checks, and other related fields. It opens up new possibilities for improving event simulation in high-energy physics research

    Exploring the Social Meaning of Curing HIV: A Qualitative Study of People Who Inject Drugs in Guangzhou, China

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    Our objective was to explore the social meaning of HIV and perceptions of an HIV cure among people who inject drugs (PWID) in Guangzhou, China, which speaks to ethical and resource challenges to development in this field. We conducted a qualitative research study using in-depth interviews. We analyzed interview transcripts from 29 PWID, eight physicians, and three social workers from an outpatient HIV clinic and two methadone maintenance treatment centers. The social meaning of HIV infection and perceptions of an HIV cure reflected patients' relationships with society, health systems, and physicians. First, HIV infection decreased perceived social worth and disrupted peer relationships. The possibility of being cured renewed patient hope for regaining physical well-being and achieving social mobility. However, the existence of a cure may not alter the HIV-related stigma due to its association with stigmatized behaviors and marginalized groups. Second, although stigma was a significant barrier to engagement in health care, hope for a cure may outweigh fears of stigma and enhance linkage to HIV testing and treatment as well as methadone services. A cure may exacerbate perceived health disparities if inaccessible to key affected populations such as PWID. The social implications of an HIV cure among this key affected population may inform the design and implementation of cure clinical trials. Careful management of patient expectations, focusing research on key affected populations, expanding HIV testing and treatment systems, improving access to harm reduction programs, and ensuring post-trial access are important considerations for HIV cure research

    Prediction of the potentially suitable areas of Ligularia virgaurea and Ligularia sagitta on the Qinghai–Tibet Plateau based on future climate change using the MaxEnt model

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    Ligularia virgaurea and Ligularia sagitta are two species of poisonous plants with strong invasiveness in natural grasslands in China that have caused considerable harm to animal husbandry and the ecological environment. However, little is known about their suitable habitats and the key environmental factors affecting their distribution. Although some studies have reported the distributions of poisonous plants on the Qinghai–Tibet Plateau (QTP) and predicted their potential distributions at local scales in some regions under climate change, there have been few studies on the widespread distributions of L. virgaurea and L. sagitta. In this study, we recorded 276 and 118 occurrence points of L. virgaurea and L. sagitta on the QTP using GPS, and then used the MaxEnt model to predict the distribution of suitable habitats. Results showed that (1) under current climate conditions, L. virgaurea and L. sagitta are mainly distributed in southern Gansu, eastern Qinghai, northwestern Sichuan, eastern Tibet, and southwestern Yunnan, accounting for approximately 34.9% and 39.8% of the total area of the QTP, respectively; (2) the main environmental variables affecting the distribution of suitable habitats for L. virgaurea and L. sagitta are the Human Footprint Index (52.8%, 42.2%), elevation (11%, 4.4%), soil total nitrogen (18.9%, 4.2%), and precipitation seasonality (5.1%, 7.3%); and (3) in the future, in the 2050s and 2070s, the area of habitat of intermediate suitability for L. virgaurea will spread considerably in northwest Sichuan, while that of high suitability for L. sagitta will spread to eastern Tibet and western Sichuan

    Quantitative analysis of nanoparticle internalization in mammalian cells by high resolution X-ray microscopy

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    <p>Abstract</p> <p>Background</p> <p>Quantitative analysis of nanoparticle uptake at the cellular level is critical to nanomedicine procedures. In particular, it is required for a realistic evaluation of their effects. Unfortunately, quantitative measurements of nanoparticle uptake still pose a formidable technical challenge. We present here a method to tackle this problem and analyze the number of metal nanoparticles present in different types of cells. The method relies on high-lateral-resolution (better than 30 nm) transmission x-ray microimages with both absorption contrast and phase contrast -- including two-dimensional (2D) projection images and three-dimensional (3D) tomographic reconstructions that directly show the nanoparticles.</p> <p>Results</p> <p>Practical tests were successfully conducted on bare and polyethylene glycol (PEG) coated gold nanoparticles obtained by x-ray irradiation. Using two different cell lines, EMT and HeLa, we obtained the number of nanoparticle clusters uptaken by each cell and the cluster size. Furthermore, the analysis revealed interesting differences between 2D and 3D cultured cells as well as between 2D and 3D data for the same 3D specimen.</p> <p>Conclusions</p> <p>We demonstrated the feasibility and effectiveness of our method, proving that it is accurate enough to measure the nanoparticle uptake differences between cells as well as the sizes of the formed nanoparticle clusters. The differences between 2D and 3D cultures and 2D and 3D images stress the importance of the 3D analysis which is made possible by our approach.</p

    Hepatitis C Virus Treatment Access Among Human Immunodeficiency Virus and Hepatitis C Virus (HCV)-Coinfected People Who Inject Drugs in Guangzhou, China: Implications for HCV Treatment Expansion.

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    Background.  Hepatitis C virus (HCV) treatment access among human immunodeficiency virus (HIV)/HCV-coinfected people who inject drugs is poor, despite a high burden of disease in this population. Understanding barriers and facilitators to HCV treatment uptake is critical to the implementation of new direct-acting antivirals. Methods.  We conducted in-depth interviews with patients, physicians, and social workers at an HIV treatment facility and methadone maintenance treatment centers in Guangzhou, China to identify barriers and facilitators to HCV treatment. We included patients who were in various stages of HCV treatment and those who were not treated. We used standard qualitative methods and organized data into themes. Results.  Interview data from 29 patients, 8 physicians, and 3 social workers were analyzed. Facilitators and barriers were organized according to a modified Consolidated Framework for Implementation Research schematic. Facilitators included patient trust in physicians, hope for a cure, peer networks, and social support. Barriers included ongoing drug use, low HCV disease knowledge, fragmented reimbursement systems, HIV exceptionalism, and stigma. Conclusions.  Expanding existing harm reduction programs, HIV treatment programs, and social services may facilitate scale-up of direct-acting antivirals globally. Improving integration of ancillary social and mental health services within existing HIV care systems may facilitate HCV treatment access

    Influence of organic aerosol molecular composition on particle absorptive properties in autumn Beijing

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    Publisher Copyright: © 2022 Jing Cai et al.Organic aerosol (OA) is a major component of fine particulate matter (PM), affecting air quality, human health, and the climate. The absorptive and reflective behavior of OA components contributes to determining particle optical properties and thus their effects on the radiative budget of the troposphere. There is limited knowledge on the influence of the molecular composition of OA on particle optical properties in the polluted urban environment. In this study, we characterized the molecular composition of oxygenated OA collected on filter samples in the autumn of 2018 in Beijing, China, with a filter inlet for gases and aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-CIMS). Three haze episodes occurred during our sampling period with daily maximum concentrations of OA of 50, 30, and 55 μg m-3. We found that the signal intensities of dicarboxylic acids and sulfur-containing compounds increased during the two more intense haze episodes, while the relative contributions of wood-burning markers and other aromatic compounds were enhanced during the cleaner periods. We further assessed the optical properties of oxygenated OA components by combining detailed chemical composition measurements with collocated particle light absorption measurements. We show that light absorption enhancement (Eabs) of black carbon (BC) was mostly related to more oxygenated OA (e.g., dicarboxylic acids), likely formed in aqueous-phase reactions during the intense haze periods with higher relative humidity, and speculate that they might contribute to lensing effects. Aromatics and nitro-aromatics (e.g., nitrocatechol and its derivatives) were mostly related to a high light absorption coefficient (babs) consistent with light-absorbing (brown) carbon (BrC). Our results provide information on oxygenated OA components at the molecular level associated with BrC and BC particle light absorption and can serve as a basis for further studies on the effects of anthropogenic OA on radiative forcing in the urban environment.Peer reviewe
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