487 research outputs found

    Measuring Invisible Particle Masses Using a Single Short Decay Chain

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    We consider the mass measurement at hadron colliders for a decay chain of two steps, which ends with a missing particle. Such a topology appears as a subprocess of signal events of many new physics models which contain a dark matter candidate. From the two visible particles coming from the decay chain, only one invariant mass combination can be formed and hence it is na\"ively expected that the masses of the three invisible particles in the decay chain cannot be determined from a single end point of the invariant mass distribution. We show that the event distribution in the log(E1T/E2T)\log(E_{1T}/E_{2T}) vs. invariant mass-squared plane, where E1TE_{1T}, E2TE_{2T} are the transverse energies of the two visible particles, contains the information of all three invisible particle masses and allows them to be extracted individually. The experimental smearing and combinatorial issues pose challenges to the mass measurements. However, in many cases the three invisible particle masses in the decay chain can be determined with reasonable accuracies.Comment: 45 pages, 32 figure

    Strain- and Adsorption-Dependent Electronic States and Transport or Localization in Graphene

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    The chapter generalizes results on influence of uniaxial strain and adsorption on the electron states and charge transport or localization in graphene with different configurations of imperfections (point defects): resonant (neutral) adsorbed atoms either oxygen- or hydrogen-containing molecules or functional groups, vacancies or substitutional atoms, charged impurity atoms or molecules, and distortions. To observe electronic properties of graphene-admolecules system, we applied electron paramagnetic resonance technique in a broad temperature range for graphene oxides as a good basis for understanding the electrotransport properties of other active carbons. Applied technique allowed observation of possible metal-insulator transition and sorption pumping effect as well as discussion of results in relation to the granular metal model. The electronic and transport properties are calculated within the framework of the tight-binding model along with the Kubo-Greenwood quantum-mechanical formalism. Depending on electron density and type of the sites, the conductivity for correlated and ordered adsorbates is found to be enhanced in dozens of times as compared to the cases of their random distribution. In case of the uniaxially strained graphene, the presence of point defects counteracts against or contributes to the band-gap opening according to their configurations. The band-gap behaviour is found to be nonmonotonic with strain in case of a simultaneous action of defect ordering and zigzag deformation. The amount of localized charge carriers (spins) is found to be correlated with the content of adsorbed centres responsible for the formation of potential barriers and, in turn, for the localization effects. Physical and chemical states of graphene edges, especially at a uniaxial strain along one of them, play a crucial role in electrical transport phenomena in graphene-based materials.Comment: 16 pages, 10 figure

    Adverse pregnancy and neonatal outcomes associated with <i>Neisseria gonorrhoeae:</i> systematic review and meta-analysis.

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    ObjectiveTo examine associations between Neisseria gonorrhoeae (NG) infection during pregnancy and the risk of preterm birth, spontaneous abortion, premature rupture of membranes, perinatal mortality, low birth weight and ophthalmia neonatorum.Data sourcesWe searched Medline, EMBASE, the Cochrane Library and Cumulative Index to Nursing and Allied Health Literature for studies published between 1948 and 14 January 2020.MethodsStudies were included if they reported testing for NG during pregnancy and compared pregnancy, perinatal and/or neonatal outcomes between women with and without NG. Two reviewers independently assessed papers for inclusion and extracted data. Risk of bias was assessed using established checklists for each study design. Summary ORs with 95% CIs were generated using random effects models for both crude and, where available, adjusted associations.ResultsWe identified 2593 records and included 30 in meta-analyses. Women with NG were more likely to experience preterm birth (OR 1.55, 95% CI 1.21 to 1.99, n=18 studies); premature rupture of membranes (OR 1.41, 95% CI 1.02 to 1.92, n=9); perinatal mortality (OR 2.16, 95% CI 1.35 to 3.46, n=9); low birth weight (OR 1.66, 95% CI 1.12 to 2.48, n=8) and ophthalmia neonatorum (OR 4.21, 95% CI 1.36 to 13.04, n=6). Summary adjusted ORs were, for preterm birth 1.90 (95% CI 1.14 to 3.19, n=5) and for low birth weight 1.48 (95% CI 0.79 to 2.77, n=4). In studies with a multivariable analysis, age was the variable most commonly adjusted for. NG was more strongly associated with preterm birth in low-income and middle-income countries (OR 2.21, 95% CI 1.40 to 3.48, n=7) than in high-income countries (OR 1.38, 95% CI 1.04 to 1.83, n=11).ConclusionsNG is associated with a number of adverse pregnancy and newborn outcomes. Further research should be done to determine the role of NG in different perinatal mortality outcomes because interventions that reduce mortality will have the greatest impact on reducing the burden of disease in low-income and middle-income countries.Prospero registration numberCRD42016050962

    A prediction rule to stratify mortality risk of patients with pulmonary tuberculosis

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    Tuberculosis imposes high human and economic tolls, including in Europe. This study was conducted to develop a severity assessment tool for stratifying mortality risk in pulmonary tuberculosis (PTB) patients. A derivation cohort of 681 PTB cases was retrospectively reviewed to generate a model based on multiple logistic regression analysis of prognostic variables with 6-month mortality as the outcome measure. A clinical scoring system was developed and tested against a validation cohort of 103 patients. Five risk features were selected for the prediction model: hypoxemic respiratory failure (OR 4.7, 95% CI 2.8-7.9), age >= 50 years (OR 2.9, 95% CI 1.7-4.8), bilateral lung involvement (OR 2.5, 95% CI 1.44.4), >= 1 significant comorbidity-HIV infection, diabetes mellitus, liver failure or cirrhosis, congestive heart failure and chronic respiratory disease-(OR 2.3, 95% CI 1.3-3.8), and hemoglobin = 6) mortality risk. The mortality associated with each group was 2.9%, 22.9% and 53.9%, respectively. The model performed equally well in the validation cohort. We provide a new, easy-to-use clinical scoring system to identify PTB patients with high-mortality risk in settings with good healthcare access, helping clinicians to decide which patients are in need of closer medical care during treatment.This work was supported by Fundacao Amelia de Mello/Jose de Mello Saude and Sociedade Portuguesa de Pneumologia (SPP). This work was developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). NSO is a FCT (Fundacao para a Ciencia e Tecnologia) investigator. MS is an Associate FCT Investigator. The fundershad no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Retrospective cohort analysis of real-life decisions about end-of-life care preferences in a Southeast Asian country

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    Objective To describe the end-of-life care preferences of individuals, and to examine the influence of age and gender on these preferences.Design, setting and participants A retrospective cohort study was conducted. Participants included all adults (>=21 years old) (n=3380) who had completed a statement of their preferences as part of a national Advance Care Planning (ACP) programme in Singapore. Data were extracted from the national and Tan Tock Seng Hospital ACP database.Main measures End-of-life care preferences were obtained from the ACP document and differentiated by health status (healthy, chronically ill or diagnosed with advanced illnesses). To analyse the data, descriptive statistics and logistic regression analysis were used.Results Across healthy and chronically ill patients, the majority did not opt for cardiopulmonary resuscitation (CPR) or other life-sustaining measures. Among individuals with advanced illnesses, 94% preferred not to attempt CPR but 69% still preferred to receive some form of active medical treatment. Approximately 40% chose to be cared for, and to die at home. Age and sex significantly predict preferences in those with advanced illnesses. Older age (&gt;=75 years) showed higher odds for home as preferred place of care (OR 1.52; 95% CI 1.23 to 1.89) and place of death (OR 1.29; 95% CI 1.03 to 1.61) and lower odds for CPR (OR 0.31; 95% CI 0.18 to 0.54) and full treatment (OR 0.32; 95% CI 0.17 to 0.62). Being female was associated with lower odds for home as preferred place of care (OR 0.69; 95% CI 0.57 to 0.84) and place of death (OR 0.70; 95% CI 0.57 to 0.85) and higher odds for full treatment (OR 2.35; 95% CI 1.18 to 4.68).Conclusion The majority preferred to not proceed with life-sustaining treatments, but there was still a strong preference to receive some form of limited treatment. Better understanding of end-of-life care preferences through ACP can better guide end-of-life care programme planning, and resource allocation decisions

    Individual, clinical and system factors associated with the place of death: A linked national database study

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    Background Many middle- and high-income countries face the challenge of meeting preferences for home deaths. A better understanding of associated factors could support the design and implementation of policies and practices to enable dying at home. This study aims to identify factors associated with the place of death in Singapore, a country with a strong sense of filial piety. Settings/participants A retrospective cohort of 62,951 individuals (≥21 years old) who had died from chronic diseases in Singapore between 2012–2015 was obtained. Home death was defined as a death that occurred in a private residence whereas non-home deaths occurred in hospitals, nursing homes, hospices and other locations. Data were obtained by extracting and linking data from five different databases. Hierarchical multivariable logistic regression models were used to examine the effects of individual, clinical and system factors sequentially. Results Twenty-eight percent of deaths occurred at home. Factors associated with home death included being 85 years old or older (OR 4.45, 95% CI 3.55–5.59), being female (OR 1.21, 95% CI 1.16–1.25), and belonging to Malay ethnicity (OR 1.91, 95% CI 1.82–2.01). Compared to malignant neoplasm, deaths as a result of diabetes mellitus (OR 1.93, 95% CI 1.69–2.20), and cerebrovascular diseases (OR 1.28, 95% CI 1.19–1.36) were also associated with a higher likelihood of home death. Independently, receiving home palliative care (OR 3.45, 95% CI 3.26–3.66) and having a documented home death preference (OR 5.08, 95% CI 3.96–6.51) raised the odds of home deaths but being admitted to acute hospitals near the end-of-life was associated with lower odds (OR 0.92, 95% CI 0.90–0.94). Conclusion Aside from cultural and clinical factors, system-based factors including access to home palliative care and discussion and documentation of preferences were found to influence the likelihood of home deaths. Increasing home palliative care capacity and promoting advance care planning could facilitate home deaths if this is the desired option of patients

    A megaxion at 750 GeV as a first hint of low scale string theory

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    Journal of High Energy Physics 2016.7 (2016): 021 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)Low scale string models naturally have axion-like pseudoscalars which couple directly to gluons and photons (but not W’s) at tree level. We show how they typically get tree level masses in the presence of closed string fluxes, consistent with the axion discrete gauge symmetry, in a way akin of the axion monodromy of string inflation and relaxion models. We discuss the possibility that the hints for a resonance at 750 GeV recently reported at ATLAS and CMS could correspond to such a heavy axion state (megaxion). Adjusting the production rate and branching ratios suggest the string scale to be of order Ms ≈ 7–104 TeV, depending on the compactification geometry. If this interpretation was correct, one extra Z’ gauge boson could be produced before reaching the string threshold at LHC and future collidersThis work is partially supported by the grants FPA2012-32828 and FPA2015-65929-P from the MINECO, the ERC Advanced Grant SPLE under contract ERC-2012-ADG-20120216-320421, the Consolider-Ingenio 2010 programme under grant MULTIDARK CSD2009-00064 and the grant SEV-2012-0249 of the “Centro de Excelencia Severo Ochoa” Programm

    Racism as a determinant of health: a systematic review and meta-analysis

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    Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants.<br /

    Hydroxychloroquine: Key therapeutic advances and emerging nanotechnological landscape for cancer mitigation.

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    Hydroxychloroquine (HCQ) is a unique class of medications that has been widely utilized for the treatment of cancer. HCQ plays a dichotomous role by inhibiting autophagy induced by the tumor microenvironment (TME). Preclinical studies support the use of HCQ for anti-cancer therapy, especially in combination with conventional anti-cancer treatments since they sensitize tumor cells to drugs, potentiating the therapeutic activity. However, clinical evidence has suggested poor outcomes for HCQ due to various obstacles, including non-specific distribution, low aqueous solubility and low bioavailability at target sites, transport across tissue barriers, and retinal toxicity. These issues are addressable via the integration of HCQ with nanotechnology to produce HCQ-conjugated nanomedicines. This review aims to discuss the pharmacodynamic, pharmacokinetic and antitumor properties of HCQ. Furthermore, the antitumor performance of the nanoformulated HCQ is also reviewed thoroughly, aiming to serve as a guide for the HCQ-based enhanced treatment of cancers. The nanoencapsulation or nanoconjugation of HCQ with nanoassemblies appears to be a promising method for reducing the toxicity and improving the antitumor efficacy of HCQ
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