Response of a Thermoacoustic Flashover Detector to Thermal Radiation

The thermoacoustic flashover detector is a device designed to be mounted on the helmet of a firefighter which creates a loud whistle when exposed to conditions that are consistent with flashover in order to provide firefighters with a warning and time to escape. The detector is based off a previous device designed at the University of Maryland which was operated using an electric band heater. This device was optimized by slightly altering the stack design and by the addition of approximately 0.3 mL of water to the stack, yielding an activation temperature of 125°C. Once the activation temperature was sufficiently lowered, the device was outfitted with copper fins which were designed to collect radiant heat from a propane-burning radiant panel and transfer it to the detector. When using four of these copper fins and exposed to a radiant heat flux of approximately 25 kW/m2, the detector activated around 125°C after 7 minutes. This was the first known activation of a thermoacoustic device to unconcentrated thermal radiation. The response time of the device was lowered after two more fins were added to the design. Once the detector was shown to work using radiant heat, it was tested at the Maryland Fire and Rescue Institute (MFRI) at the University of Maryland using full scale fires in order to replicate the conditions in which it would be expected to operate. While the detector did not activate during the full scale tests, the radiant panel tests proved that the design is feasible and that some slight design changes are needed in order for the detector to operate in a real fire environment

Wildfires identification: Semantic segmentation using support vector machine classifier

summary:This paper deals with wildfire identification in the Alaska regions as a semantic segmentation task using support vector machine classifiers. Instead of colour information represented by means of BGR channels, we proceed with a normalized reflectance over 152 days so that such time series is assigned to each pixel. We compare models associated with $\mathcal{l}1$-loss and $\mathcal{l}2$-loss functions and stopping criteria based on a projected gradient and duality gap in the presented benchmarks

Novel Oral Anticoagulants: A Comparative Study of the Clinical Potential for Dabigatran, Rivaroxaban, and Apixaban versus Warfarin

Although Coumadin® (warfarin) has been the standard outpatient anticoagulant for long-term prevention of thrombosis for many decades, it presents with significant challenges for both patients and health care providers in optimizing standards of care including dietary and drug restrictions, regular monitoring of the patient\u27s International Normalized Ratio (INR), and difficulty maintaining therapeutic levels. Despite its unmistakable effectiveness, there has been an interest from the medical community in developing potential alternative drug therapies. As a result, within the past three years the U.S. Food and Drug Administration (FDA) has approved the use of three new oral anticoagulant drugs (dabigatran, rivaroxaban, and apixaban) specifically targeting thrombin or factor Xa that have overcome many of the barriers seen in warfarin therapy. The use of these new oral anticoagulants is of particular interest in patients who have failed warfarin therapy or for whom warfarin therapy is contraindicated, in situations when monitoring is not feasible or interactions are problematic, or if patient INR control is poor. All of these novel agents are currently approved for prevention of thrombosis in patients with nonvalvular atrial fibrillation, and with ongoing clinical research these agents may present health care providers with additional therapeutic options in a greater variety of disease states. For the comparative purposes of this article, we have combined all of the recent clinical evidence and major landmark trials for each of these new agents as well as benefits and drawbacks of therapy in specific patient populations when compared to warfarin

Repurposing the GNAT Fold in the Initiation of Polyketide Biosynthesis.

Natural product biosynthetic pathways are replete with enzymes repurposed for new catalytic functions. In some modular polyketide synthase (PKS) pathways, a GCN5-related N-acetyltransferase (GNAT)-like enzyme with an additional decarboxylation function initiates biosynthesis. Here, we probe two PKS GNAT-like domains for the dual activities of S-acyl transfer from coenzyme A (CoA) to an acyl carrier protein (ACP) and decarboxylation. The GphF and CurA GNAT-like domains selectively decarboxylate substrates that yield the anticipated pathway starter units. The GphF enzyme lacks detectable acyl transfer activity, and a crystal structure with an isobutyryl-CoA product analog reveals a partially occluded acyltransfer acceptor site. Further analysis indicates that the CurA GNAT-like domain also catalyzes only decarboxylation, and the initial acyl transfer is catalyzed by an unidentified enzyme. Thus, PKS GNAT-like domains are re-classified as GNAT-like decarboxylases. Two other decarboxylases, malonyl-CoA decarboxylase and EryM, reside on distant nodes of the superfamily, illustrating the adaptability of the GNAT fold

Locality and digital quantum simulation of power-law interactions

The propagation of information in non-relativistic quantum systems obeys a speed limit known as a Lieb-Robinson bound. We derive a new Lieb-Robinson bound for systems with interactions that decay with distance $r$ as a power law, $1/r^\alpha$. The bound implies an effective light cone tighter than all previous bounds. Our approach is based on a technique for approximating the time evolution of a system, which was first introduced as part of a quantum simulation algorithm by Haah et al., FOCS'18. To bound the error of the approximation, we use a known Lieb-Robinson bound that is weaker than the bound we establish. This result brings the analysis full circle, suggesting a deep connection between Lieb-Robinson bounds and digital quantum simulation. In addition to the new Lieb-Robinson bound, our analysis also gives an error bound for the Haah et al. quantum simulation algorithm when used to simulate power-law decaying interactions. In particular, we show that the gate count of the algorithm scales with the system size better than existing algorithms when $\alpha>3D$ (where $D$ is the number of dimensions).Comment: 18 pages, 10 figure

Micro-RNAs Are Related to Epicardial Adipose Tissue in Participants With Atrial Fibrillation: Data From the MiRhythm Study

Introduction: Epicardial adipose tissue (EAT) has been linked to incidence and recurrence of atrial fibrillation (AF), but the underlying mechanisms that mediate this association remain unclear. Circulating microRNAs (miRNAs) contribute to the regulation of gene expression in cardiovascular diseases, including AF. Thus, we sought to test the hypothesis that circulating miRNAs relate to burden of EAT. Methods: We examined the plasma miRNA profiles of 91 participants from the miRhythm study, an ongoing study examining associations between miRNA and AF. We quantified plasma expression of 86 unique miRNAs commonly expressed in cardiomyocytes using quantitative reverse transcriptase polymerase chain reaction (qPCR). From computed tomography, we used validated methods to quantify the EAT area surrounding the left atrium (LA) and indexed it to body surface area (BSA) to calculate indexed LA EAT (iLAEAT). Participants were divided into tertiles of iLAEAT to identify associations with unique miRNAs. We performed logistic regression analyses adjusting for factors associated with AF to examine relations between iLAEAT and miRNA. We performed further bioinformatics analysis of miRNA predicted target genes to identify potential molecular pathways are regulated by the miRNAs. Results: The mean age of the participants was 59 +/- 9, 35% were women, and 97% were Caucasian. Participants in the highest tertile of iLAEAT were more likely to have hypertension, heart failure, and thick posterior walls. In regression analyses, we found that miRNAs 155-5p (p \u3c 0.001) and 302a-3p (p \u3c 0.001) were significantly associated with iLAEAT in patients with AF. The predicted targets of the miRNAs identified were implicated in the regulation of cardiac hypertrophy, adipogenesis, interleukin-8 (IL-8), and nerve growth factor (NGF) signaling. Conclusion: miRNA as well as EAT have previously been linked to AF. Our finding that iLAEAT and miRNAs 155-5p and 302a-3p are associated suggest a possible direct link to between these entities in the development and maintenance of AF. Further research is needed to study causal relationships between these biomarkers

Blackcurrants Reduce the Risk of Postmenopausal Osteoporosis: A Pilot Double-Blind, Randomized, Placebo-Controlled Clinical Trial.

Beneficial effects of blackcurrant supplementation on bone metabolism in mice has recently been demonstrated, but no studies are available in humans. The current study aimed to examine the dose-dependent effects of blackcurrant in preventing bone loss and the underlying mechanisms of action in adult women. Forty peri- and early postmenopausal women were randomly assigned into one of three treatment groups for 6 months: (1) a placebo (control group, n = 13); (2) 392 mg/day of blackcurrant powder (low blackcurrant, BC, group, n = 16); and (3) 784 mg/day of blackcurrant powder (high BC group, n = 11). The significance of differences in outcome variables was tested by repeated-measures ANOVA with treatment and time as between- and within-subject factors, respectively. Overall, blackcurrant supplementation decreased the loss of whole-body bone mineral density (BMD) compared to the control group (p \u3c 0.05), though the improvement of whole-body BMD remained significant only in the high BC group (p \u3c 0.05). Blackcurrant supplementation also led to a significant increase in serum amino-terminal propeptide of type 1 procollagen (P1NP), a marker of bone formation (p \u3c 0.05). These findings suggest that daily consumption of 784 mg of blackcurrant powder for six months mitigates the risk of postmenopausal bone loss, potentially through enhancing bone formation. Further studies of larger samples with various skeletal conditions are warranted to confirm these findings