The Most Massive Ultra-Compact Dwarf Galaxy in the Virgo Cluster

We report on the properties of the most massive ultra-compact dwarf galaxy (UCD) in the nearby Virgo Cluster of galaxies using imaging from the Next Generation Virgo Cluster Survey (NGVS) and spectroscopy from Keck/DEIMOS. This object (M59-UCD3) appears to be associated with the massive Virgo galaxy M59 (NGC 4621), has an integrated velocity dispersion of 78 km/s, a dynamical mass of $3.7\times10^8 M_\odot$, and an effective radius ($R_e$) of 25 pc. With an effective surface mass density of $9.4\times10^{10} M_\odot/kpc^2$, it is the densest galaxy in the local Universe discovered to date, surpassing the density of the luminous Virgo UCD, M60-UCD1. M59-UCD3 has a total luminosity of $M_{g'}=-14.2$ mag, and a spectral energy distribution consistent with an old (14 Gyr) stellar population with [Fe/H]=0.0 and [$\alpha$/Fe]=+0.2. We also examine deep imaging around M59 and find a broad low surface brightness stream pointing towards M59-UCD3, which may represent a tidal remnant of the UCD progenitor. This UCD, along with similar objects like M60-UCD1 and M59cO, likely represents an extreme population of tidally stripped galaxies more akin to larger and more massive compact early-type galaxies than to nuclear star clusters in present-day dwarf galaxies.Comment: 6 pages, 4 figures, 1 table, accepted for publication in ApJ Letter

Solvothermal synthesis of SnO2/graphene nanocomposites for supercapacitor application

A facile solvent-based synthesis route based on the oxidation–reduction reaction between graphene oxide (GO) and SnCl2·2H2O has been developed to synthesize SnO2/graphene (SnO2/G) nanocomposites. The reduction of GO and the in situ formation of SnO2 nanoparticles were achieved in one step. Characterization by X-ray diffraction (XRD), ultraviolet-visible (UV–vis) absorption spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy (FESEM) confirmed the feasibility of using the solvothermally treated reaction system to simultaneously reduce GO and form SnO2 nanoparticles with an average particle size of 10 nm. The electrochemical performance of SnO2/graphene showed an excellent specific capacitance of 363.3 F/g, which was five-fold higher than that of the as-synthesized graphene (68.4 F/g). The contributing factors were the synergistic effects of the excellent conductivity of graphene and the nanosized SnO2 particles

Burnout and work-related stressors in gastroenterology: a protocol for a multinational observational study in the ASEAN region.

BACKGROUND: Clinician burnout is an important occupational hazard that may be exacerbated by the novel COVID-19 pandemic. Within Southeast Asia, burnout in gastroenterology is understudied. The primary objective of this study is to estimate the prevalence of burnout symptoms within gastroenterology, in member states of the Associations of Southeast Asian Nations (ASEAN), during and after the COVID-19 pandemic. The secondary objective is to identify work-related stressors that contribute to burnout in ASEAN gastroenterologists. METHODS AND ANALYSIS: This is an observational study that will use anonymised online surveys to estimate the prevalence of burnout symptoms at two time points: during the COVID-19 pandemic in 2020 and in 2022 (assumed to be after the pandemic). Gastroenterologists from Singapore, Malaysia, Thailand, Indonesia, Philippines and Brunei will be invited to participate in the online survey through their national gastroenterology and endoscopy societies. Burnout will be assessed using the Maslach Burnout Inventory-Human Services Survey tool. Supplementary questions will collect demographic and qualitative data. Associations between demographic characteristics and burnout will be tested by multiple regression. RESULTS: The prevalence of burnout symptoms in gastroenterology during the COVID-19 pandemic, and the baseline prevalence after COVID-19, will be established in the above-mentioned countries. Work-related stressors commonly associated with burnout will be identified, allowing the introduction of preventative measures to reduce burnout in the future. ETHICS AND DISSEMINATION: Ethical approval was granted by the Singhealth Centralised Institutional Review Board (2020/2709). Results will be submitted for publication

Identification of leukocyte surface P2X7 as a biomarker associated with Alzheimer\u27s disease

Alzheimer\u27s disease (AD) has shown altered immune responses in the periphery. We studied P2X7 (a proinflammatory receptor and a scavenger receptor) and two integrins, CD11b and CD11c, on the surface of circulating leukocytes and analysed their associations with Aβ-PET, brain atrophy, neuropsychological assessments, and cerebrospinal fluid (CSF) biomarkers. Total 287 age-matched, sex-balanced participants were recruited in a discovery cohort and two validation cohorts through the AIBL study and studied using tri-colour flow cytometry. Our results demonstrated reduced expressions of P2X7, CD11b, and CD11c on leukocytes, particularly monocytes, in Aβ +ve cases compared with Aβ -ve controls. P2X7 and integrin downregulation was observed at pre-clinical stage of AD and stayed low throughout disease course. We further constructed a polygenic risk score (PRS) model based on 12 P2RX7 risk alleles to assess the genetic impact on P2X7 function in AIBL and ADNI cohorts. No significant association was identified between the P2RX7 gene and AD, indicating that P2X7 downregulation in AD is likely caused by environmental changes rather than genetic factors. In conclusion, the downregulation of P2X7 and integrins at pre-clinical stage of AD indicates altered pro-inflammatory responses, phagocytic functions, and migrating capabilities of circulating monocytes in early AD pathogenesis. Our study not only improves our understanding of peripheral immune involvement in early stage of AD but also provides more insights into novel biomarker development, diagnosis, and prognosis of AD

The Long Distance Contribution to D→πl+l−D\to\pi l^+l^-

We calculate the long distance contribution to $D^{+,0}\to\pi^{+,0}l^+l^-$ decays by the use of a vector meson dominance model, in which the $\phi$-meson plays the central role. The branching ratios obtained are $10^{-6}$ and a few times $10^{-7}$ for the resonance and non-resonance regions respectively. The analysis includes a calculation of $D^+\to\pi^+\phi$, consistent with the experimental value.Comment: Latex file, 10 pages, no figur

A Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

Document submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresDocument submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresDocument submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresHyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of $CP$ asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this document, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis has been updated from the previous Letter of Intent [K. Abe et al., arXiv:1109.3262 [hep-ex]], based on the experience gained from the ongoing T2K experiment. With a total exposure of 7.5 MW $\times$ 10$^7$ sec integrated proton beam power (corresponding to $1.56\times10^{22}$ protons on target with a 30 GeV proton beam) to a $2.5$-degree off-axis neutrino beam produced by the J-PARC proton synchrotron, it is expected that the $CP$ phase $\delta_{CP}$ can be determined to better than 19 degrees for all possible values of $\delta_{CP}$, and $CP$ violation can be established with a statistical significance of more than $3\,\sigma$ ($5\,\sigma$) for $76$ ($58$) of the $\delta_{CP}$ parameter space

Leukocyte surface biomarkers implicate deficits of innate immunity in sporadic Alzheimer\u27s disease

Introduction: Blood-based diagnostics and prognostics in sporadic Alzheimer\u27s disease (AD) are important for identifying at-risk individuals for therapeutic interventions. Methods: In three stages, a total of 34 leukocyte antigens were examined by flow cytometry immunophenotyping. Data were analyzed by logistic regression and receiver operating characteristic (ROC) analyses. Results: We identified leukocyte markers differentially expressed in the patients with AD. Pathway analysis revealed a complex network involving upregulation of complement inhibition and downregulation of cargo receptor activity and Aβ clearance. A proposed panel including four leukocyte markers – CD11c, CD59, CD91, and CD163 – predicts patients’ PET Aβ status with an area under the curve (AUC) of 0.93 (0.88 to 0.97). CD163 was the top performer in preclinical models. These findings have been validated in two independent cohorts. Conclusion: Our finding of changes on peripheral leukocyte surface antigens in AD implicates the deficit in innate immunity. Leukocyte-based biomarkers prove to be both sensitive and practical for AD screening and diagnosis

The impact of the coronavirus disease 2019 pandemic on gastroenterologists in Southeast Asia: A mixed-methods study.

Funder: National University of Singapore; Id: http://dx.doi.org/10.13039/501100001352Funder: University of Cambridge; Id: http://dx.doi.org/10.13039/501100000735Funder: JGH FoundationBACKGROUND AND AIM: The coronavirus disease 2019 pandemic has impacted gastroenterology practices worldwide; however, its protracted effects within Southeast Asia were unknown. The primary aim of the study was to determine the impact of the pandemic on clinical demands including burnout among gastroenterologists within the region. The secondary aim was to identify risk factors for burnout and determine regional stressors. METHODS: This was a mixed-methods study. Gastroenterologists were surveyed electronically between September 1 and December 7, 2020, via gastroenterology and endoscopy societies of Brunei, Indonesia, Malaysia, Philippines, Singapore, and Thailand. Quantitative and qualitative data were collected. The 22-item Maslach Burnout Inventory-Human Services Survey (MBI-HSS) was used to detect burnout. Quantitative data were non-parametric; non-parametric methods were used for statistical comparisons. Logistic regression was used to determine risk factors for burnout. Content analysis method was used to analyze qualitative data. Ethical approval was obtained. RESULTS: A total of 73.0% reported that they were still significantly affected by the pandemic. Of these, 40.5% reported increased workload and 59.5% decreased workload. Statistically significant differences in weekly working hours, endoscopy, and inpatient volumes were present. No differences were observed in outpatient volumes, likely because of telemedicine. Burnout was common; however, 50.1% of gastroenterologists were unaware of or did not have access to mental health support. This, as well as depression, being a trainee, and public sector work, increased burnout risk significantly. CONCLUSION: The effects of the pandemic are multifaceted, and burnout is common among Southeast Asian gastroenterologists. Safeguards for mental health are suboptimal, and improvements are urgently needed