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Large-scale dynamics of tropical cyclone formation associated with the ITCZ breakdown
No full textThis study examines the formation of tropical cyclones (TCs) from the large-scale perspective. Using the nonlinear dynamical transition framework recently developed by Ma and Wang, it is shown that the large-scale formation of TCs can be understood as a result of the principle of exchange of stabilities in the barotropic model for the intertropical convergence zone (ITCZ). Analyses of the transition dynamics at the critical point reveal that the maximum number of TC disturbances that the Earth's tropical atmosphere can support at any instant of time has an upper bound of ∼12 for current atmospheric conditions. Additional numerical estimation of the transition structure on the central manifold at the critical point of the ITCZ model confirms this important finding, which offers an explanation for a fundamental question of why the Earth's atmosphere can support a limited number of TCs globally each year
Thawing, Culturing, and Cryopreserving Drosophila Cell Lines
No full textThere are currently over 160 distinct Drosophila cell lines distributed by the Drosophila Genomics Resource Center (DGRC). With genome engineering, the number of novel cell lines is expected to increase. The DGRC aims to familiarize researchers with using Drosophila cell lines as an experimental tool to complement and drive their research agenda. Procedures for working with a variety of Drosophila cell lines with distinct characteristics are provided, including protocols for thawing, culturing, and cryopreserving cell lines. Importantly, this publication demonstrates the best practices required to work with Drosophila cell lines to minimize the risk of contaminations from adventitious microorganisms or from other cell lines. Researchers who become familiar with these procedures will be able to delve into the many applications that use Drosophila cultured cells including biochemistry, cell biology and functional genomics
Need for Aeromedical Evacuation High-Level Containment Transport Guidelines
No full textCircumstances exist that call for the aeromedical evacuation high-level containment transport (AE-HLCT) of patients with highly hazardous communicable diseases. A small number of organizations maintain AE-HLCT capabilities, and little is publicly available regarding the practices. The time is ripe for the development of standards and consensus guidelines involving AE-HLCT
Money and influence: philanthropies, intermediary organisations, and Atlanta's 2017 school board election
No full textNational philanthropies have recently played a prominent role in spending on U.S. urban school board elections, largely seeking to promote candidates who support charter schools. In Atlanta in 2017, 30 candidates competed for nine open school board seats. One practice has been to fund intermediary organisations (IOs) (e.g. advocacy groups, foundations) that disseminate information and research in an effort to shape public opinion. This paper analyses the role of IOs in the 2017 school board race in Atlanta. Drawing on 12 interviews with policymakers and IO representatives, analysis of campaign literature, and media accounts, the authors contrast the ways in which the intermediary and philanthropic sectors attempted to influence leaders’ framing of educational policy issues. Findings reveal a nascent capacity for IOs in Atlanta for shaping support for pro-charter board candidates. The paper discusses implications for understanding the role that IOs may play in the politics of urban education
Gender and Mathematics: What Can Other Disciplines Tell Us? What is Our Role?
No full textIn this article, we begin by taking stock of broad trends related to gender and mathematics, focusing primarily on patterns within the United States. We then add some important nuance, discussing some ways in which patterns vary by social class and race. Given that much recent work on gender and mathematics has been situated outside of traditional mathematics education frames, we consider how ongoing work in psychology and gender studies can contribute to our understanding, using interview data from a study of woman’s experiences in a mathematics Ph.D. program. Ultimately, we argue that mathematics education researchers bring unique expertise to the table and have a particular role to play in building upon work in other fields to further the work on gender and mathematics
The X-ray Emissivity of Low-Density Stellar Populations
No full textThe dynamical production of low-mass X-ray binaries and brighter cataclysmic variables (CVs) in dense globular clusters is well-established. We investigate how the X-ray emissivity of fainter X-ray binaries (principally CVs and coronally active binaries) varies between different environments. We compile calculations (largely from the literature) of the X-ray emissivity of old stellar populations, including open and globular clusters and several galaxies. We investigate three literature claims of unusual X-ray sources in low-density stellar populations. We show that a suggested quiescent neutron star in the open cluster NGC 6819 is a foreground M dwarf. We show that the suggested diffuse X-ray emission from an old nova shell in the globular cluster NGC 6366 is actually a background galaxy cluster. And we show that a suggested population of quiescent X-ray binaries in the Sculptor Dwarf Galaxy is mostly (perhaps entirely) background galaxies. We find that above densities of 104 M pc, the X-ray emissivity of globular clusters increases, due to dynamical production of X-ray emitting systems. Below this density, globular clusters have lower X-ray emissivity than the other populations, and we do not see a strong dependence of X-ray emissivity due to density effects. We find significant correlations between X-ray emissivity and binary fraction, metallicity, and density. Sampling these fits via bootstrap techniques gives less significant correlations, but confirms the effect of metallicity on low-density populations, and that of density on the full globular cluster sample
Identifications of faintChandrasources in the globular cluster M3
No full textWe report a 30 ks Chandra ACIS-S survey of the globular cluster M3. Sixteen X-ray sources were detected within the half-light radius (2.3 ') with . We used Hubble Space Telescope WFC3/UVIS and ACS/WFC images to find 10 plausible optical/UV counterparts. We fit the spectral energy distribution of the known cataclysmic variable (CV) 1E1339.8+2837 with a blue (, 90 per cent conf.) spectral component from an accretion disc, plus a red component () potentially from a subgiant donor. The second brightest source (CX2) has a soft blackbody-like spectrum suggesting a quiescent low-mass X-ray binary (qLMXB) containing a neutron star. Six new counterparts have obvious UV and/or blue excesses, suggesting a CV or background active galactic nucleus (AGN) nature. Two (CX6 and CX8) have proper motions (PMs) indicating cluster membership, suggesting a CV nature. CX6 is blue in UV filters but red in V–I, which is difficult to interpret. Two CV candidates, CX7 and CX13, show blue excesses in B–V colour but were not detected in the UV. The other two CV candidates were only detected in the two UV bands (UV and NUV), so do not have PM measurements, and may well be AGNs. One Chandra source can be confidently identified with a red straggler (a star reward of the giant branch). The observed X-ray source population of M3 appears consistent with its predicted stellar interaction rate
The association between statins and colorectal cancer stage in the Women's Health Initiative
No full textThe anticarcinogenic effect of statins may reduce the metastatic potential of cancer cells leading to ‘stage migration', with users more likely diagnosed with early rather than late stage cancer. The association between prior statin use and colorectal cancer (CRC) stage at diagnosis in the Women's Health Initiative (WHI) was investigated. The study population included 132,322 post‑menopausal women, among which there were 2,628 pathologically confirmed cases of in situ (3.3%), localized (43.6%), regional (40.4%) and distant (12.7%) stage CRC, after an average of 13.9 (SD=4.7) years of follow‑up. To reduce the possibility of detection bias among women more likely to be prescribed statins, women who did not report a mammogram within 5 years of study entry and who had no health insurance or medical care provider (n=28,237) were excluded from the study. Stage was coded using SEER criteria into early (in situ and local) vs. late (regional and distant) stage disease. Hazards ratios (HR) and 95% confidence intervals (CIs) evaluating the association between statin use and diagnosis of late‑stage CRC both at baseline and in a time‑dependent manner were computed from multivariable‑adjusted Cox proportional hazards analyses. In the multivariable time‑dependent analysis, there was a lower hazard of late stage CRC among users of lipophilic statins compared with non‑users (HR=0.80, 95% CI 0.66‑0.98, P=0.029) and a marginally lower hazard of late stage CRC among users of lipophilic vs. hydrophilic statins (HR=0.70, 95% CI 0.49‑1.01, P=0.058). The use of lipophilic statins was associated with a reduction in the proportion of CRC cases that were late stage at the time of diagnosis
Biomarkers of dietary omega-6 fatty acids and incident cardiovascular disease and mortality: an individual-level pooled analysis of 30 cohort studies
No full textWeight loss, diet composition and breast cancer incidence and outcome in postmenopausal women
No full textTwo complementary studies in separate components of the Women’s Health Initiative (WHI) examined relationships among weight loss, diet composition and breast cancer incidence and outcome in postmenopausal women. In the WHI Observational Study, 61,335 postmenopaus al women had their weight change determined over a 3-year period with subsequent follow-up. Women with weight loss greater than or equal to 5% had significantly lower breast cancer incidence compared to women with stable weight. In the WHI Dietary Modification randomized clinical trial involving 48,835 postmenopausal women, implementation of a low-fat eating pattern significantly reduced deaths after breast cancer. Thus, moderation regarding dietary composition and body weight maintenance can reduce a postmenopausal woman’s risk of being diagnosed with breast cancer and of dying after breast cancer