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MHONGOOSE Discovery of a Gas-Rich Low Surface Brightness Galaxy in the Dorado Group
Get PDFWe present the discovery of a low-mass, gas-rich low surface brightness galaxy in the Dorado group, at a distance of 17.7 Mpc. Combining deep MeerKAT 21-cm observations from the MeerKAT Hi Observations of Nearby Galactic Objects: Observing Southern Emitters (MHONGOOSE) survey with deep photometric images from the VST Early-type Galaxy Survey (VEGAS) we find a stellar and neutral atomic hydrogen (H i) gas mass of M∗ = 2:23 × 106M⊙ and MHI = 1:68 × 106 M⊙, respectively. This low surface brightness galaxy is the lowest-mass Hi detection found in a group beyond the local Universe (D ≳ 10 Mpc). The dwarf galaxy has the typical overall properties of gas-rich low surface brightness galaxies in the Local group, but with some striking differences. Namely, the MHONGOOSE observations reveal a very low column density (∼ 1018-19 cm-2) Hi disk with asymmetrical morphology possibly supported by rotation and higher velocity dispersion in the centre. There, deep optical photometry and UV observations suggest a recent enhancement of the star formation. Found at galactocentric distances where in the Local Group dwarf galaxies are depleted of cold gas (at a projected distance of 390 kpc from the group centre), this galaxy is likely on its first orbit within the Dorado group. We discuss the possible environmental effects that may have caused the formation of the Hi disk and the enhancement of star formation (SF), highlighting the short-lived phase (a few hundreds million years) of the gaseous disk, before either SF or hydrodynamical forces will deplete the gas of the galaxy
Geometric Representation of Classes of Concave Functions and Duality
No full textUsing a natural representation of a 1/s-concave function on R ᵈ as a convex set in R ᵈ⁺¹, we derive a simple formula for the integral of its s-polar. This leads to convexity properties of the integral of the s-polar function with respect to the center of polarity. In particular, we prove that the reciprocal of the integral of the polar function of a log-concave function is log-concave as a function of the center of polarity. Also, we define the Santaló regions for s-concave and log-concave functions and generalize the Santaló inequality for them in the case the origin is not the Santaló point
On the Nature of Transverse Waves in Marginal Hydrogen Detonation Simulations using Boundary Layer Loss Modeling and Detailed Chemistry
No full textHistorically, it has been a challenge to simulate the experimentally observed cellular structures and marginal behavior of multi-dimensional, thin-channel hydrogen detonations in the presence of losses, even with detailed chemistry models. Very recently, a quasi-two-dimensional inviscid approach with a calorically perfect gas and two-step chemistry was pursued, where losses due to viscous boundary layers were modeled by the inclusion of an equivalent mass divergence in the lateral direction using Fay\u27s source term formulation with Mirels’ compressible laminar boundary layer solutions. A similar approach was adopted for this study, but with the inclusion of thermally-perfect detailed chemistry in order to capture the correct ignition sensitivity of the gas to dynamic changes in the thermodynamic state behind the detonation front. In addition, the strength of transverse waves and their impact on the detonation front was investigated. Here, the detailed San Diego mechanism was applied. For marginal cases, where the detonation waves approach their failure limit, quasi-stable mode behavior was observed where the number of transverse waves monotonically decreased to a single strong wave over a long enough distance. The strong transverse waves were also found to be slightly weaker than the detonation front, indicating that they are not overdriven relative to the shocked gas in which they propagate, in agreement with recent studies. Numerical experiments at lower pressures close to the quenching limit also suggest the existence of additional longitudinal waves formed through wall-collision-induced autoignition of unburned gas pockets. These waves could potentially be stronger than the transverse waves and help stabilize and even sustain the detonation. Novelty and Significance This work extends previous numerical investigations of hydrogen detonations in thin channels by including thermally-perfect detailed chemistry and advection of the shock time scalar in Fay\u27s mass divergence source term formulation with Mirels’ constant. This work is accurately able to recover experimental observations and also applies the mass divergence formulation to mixtures and conditions closer to the quenching limit than has been done before. The methodology used efficiently allows important details of marginal behavior found behind the detonation front to be resolved and quantified clearly. These numerical results suggest the existence of additional longitudinal waves behind the shock front which are found to play an important role in sustaining detonations at marginal conditions
Self-Monitoring of Weight as a Weight Loss Strategy: A Systematic Review
Get PDFPurpose of Review: Gauge the effectiveness of self-monitoring of weight for weight loss. Recent Findings: Daily self-monitoring of weight results in increased weight loss, or improved weight maintenance as compared to infrequent or no self-monitoring of weight. Self-weighing is most effective when tied with other behavioral interventions including tracking caloric intake and physical activity tracking. Summary: Self-monitoring of weight is an effective behavioral weight loss intervention which allows patients to track their progress, but also allows them to connect daily life activities with their weight, fostering real-time feedback that allows them to make more informed and personalized decisions related to dietary choices, physical activity, and lifestyle medicine
The Flint Water Crisis and the Perpetuation of Environmental Racism in Flint, Michigan (2014–2018)
No full textThe nexus between environmental racism and racial capitalism has been well documented. However, the government is often blamed for the perpetuation of some forms of environmental racism. Nonetheless, blaming the government for environmental racism without documenting some actions and policy implementation by the government to mitigate or prevent the re-occurrence of environmental racism tends to be a one-sided view. Consequently, this study examines how the American government plays some roles in the occurrence of environmental racism, that is, the Flint Water Crisis (FWC) in Michigan. Racial capitalism theory is used as a theoretical lens in this study. Racial capitalism, historical residential housing policies, anti-blackness or devaluation of Black bodies, the appointment of Emergency Financial Managers, environmental racism, neoliberalism, laissez-faire, and color-blind racism were the mechanisms driving the occurrence of the FWC. The different actions and policies that were taken by the American government to mitigate or prevent the re-emergence of FWC were also documented. Although, these actions were taken after the occurrence of the FWC. The materials-based method (secondary data) was not only adopted to provide answers to the research question that this study answered but was also used to explain the global dynamic and operation of racial capitalism
Reply To: On The Statistical Foundation of a Recent Single Molecule Fret Benchmark
Get PDFIn their ‘Matters Arising’ manuscript, Saurabh et al. discuss two issues related to single-molecule Förster resonance energy transfer (smFRET) experiments: the use of the Gaussian noise approximation and spectral crosstalk. Their arguments are based on simulations obtained with parameters that differ significantly from the typical conditions measured experimentally, and, thus, from the regime included in the original study (Götz et al.1). In addition, they make claims about our multi-lab blind study that we would like to rectify. In Table 1, we provide a list of specific statements made by Saurabh et al. with our respective explanations
SHEA Position Statement on Pandemic Preparedness for Policymakers: Introduction and Overview
Get PDFThroughout history, pandemics and their aftereffects have spurred society to make substantial improvements in healthcare. After the Black Death in 14th century Europe, changes were made to elevate standards of care and nutrition that resulted in improved life expectancy.1 The 1918 influenza pandemic spurred a movement that emphasized public health surveillance and detection of future outbreaks and eventually led to the creation of the World Health Organization Global Influenza Surveillance Network.2 In the present, the COVID-19 pandemic exposed many of the pre-existing problems within the US healthcare system, which included (1) a lack of capacity to manage a large influx of contagious patients while simultaneously maintaining routine and emergency care to non-COVID patients; (2) a just in time supply network that led to shortages and competition among hospitals, nursing homes, and other care sites for essential supplies; and (3) longstanding inequities in the distribution of healthcare and the healthcare workforce. The decades-long shift from domestic manufacturing to a reliance on global supply chains has compounded ongoing gaps in preparedness for supplies such as personal protective equipment and ventilators. Inequities in racial and socioeconomic outcomes highlighted during the pandemic have accelerated the call to focus on diversity, equity, and inclusion (DEI) within our communities. The pandemic accelerated cooperation between government entities and the healthcare system, resulting in swift implementation of mitigation measures, new therapies and vaccinations at unprecedented speeds, despite our fragmented healthcare delivery system and political divisions. Still, widespread misinformation or disinformation and political divisions contributed to eroded trust in the public health system and prevented an even uptake of mitigation measures, vaccines and therapeutics, impeding our ability to contain the spread of the virus in this country.3 Ultimately, the lessons of COVID-19 illustrate the need to better prepare for the next pandemic. Rising microbial resistance, emerging and re-emerging pathogens, increased globalization, an aging population, and climate change are all factors that increase the likelihood of another pandemic
Feasibility of a Low-Intensity Intervention to Influence Antibiotic Prescribing Rates Use in Outpatient Settings: A Cluster Randomized Controlled Clinical Trial
Get PDFBackground. Primary care providers (PCPs) may modify their antibiotic prescription practices if aware of their potentially damaging impact. Methods. We conducted a cluster randomized controlled trial at 12 Veterans Affairs community-based outpatient clinics. PCPs at clinics randomized to the intervention group received quarterly antibiotic use reports with feedback about antibiotics prescribed for acute respiratory infections and adverse event letters alerting about Clostridioides difficile infection or antibiotic-resistant gram-negative bacteria among their patients. The main outcome, antibiotic prescriptions in primary care visits, was compared in the preintervention (April–September 2020), intervention (October 2020 to September 2021), and postintervention periods (September 2021 to September 2022). Results. Among 52 PCPs at 6 clinics in the intervention group, 66% (33 of 52) and 54% (28 of 52) received ≥1 antibiotic use report and adverse event letter. In the intervention clinics, the proportion of primary care visits with antibiotic prescription during the preintervention, intervention, and postintervention periods was 1.4% (1088 of 77 697), 1.4% (2051 of 147 858), and 1.3% (1692 of 131 530). In the control clinics, this increased from 1.8% (1560 of 87 897) to 2.1% (3707 of 176 825) and 2.1% (3418 of 162 979), respectively, during the intervention and postintervention periods. The rate of visits with antibiotic prescription did not differ in the preintervention period (odds ratio [95% confidence interval], 1.10 [.87–1.39); P = .43) but did during the intervention (1.30 [1.04–1.62]; P = .022) and postintervention periods (1.38 [1.09–1.74]; P = .007). There were no differences in emergency department visits and hospitalizations. Conclusions. PCPs from clinics assigned to a low-intensity intervention combining comparative feedback with adverse event notifications had lower antibiotic prescription rates
L-PBF High-Throughput Data Pipeline Approach for Multi-Modal Integration
Get PDFMetal-based additive manufacturing requires active monitoring solutions for assessing part quality. Multiple sensors and data streams, however, generate large heterogeneous data sets that are impractical for manual assessment and characterization. In this work, an automated pipeline is developed that enables feature extraction from high-speed camera video and multi-modal data analysis. The framework removes the need for manual assessment through the utilization of deep learning techniques and training models in a weakly supervised paradigm. We demonstrate this pipeline’s capability over 700,000 high-speed camera frames. The pipeline successfully extracts melt pool and spatter geometries and links them to corresponding pyrometry, radiography, and processparameter information. 715 individual prints are examined to reveal melt pool areas that exceeds 0.07 mm2 and pyrometry signal over a threshold (375 pyrometry units) were more likely to have defects. These automated processes enable massive throughput of characterization techniques
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