Band mixing in the quantum anomalous Hall regime of twisted semiconductor bilayers

Remarkable recent experiments have observed fractional quantum anomalous Hall (FQAH) effects at zero field and unusually high temperatures in twisted semiconductor bilayer $t$MoTe$_2$. Intriguing observations in these experiments such as the absence of integer Hall effects at twist angles where a fractional Hall effect is observed, do however remain unexplained. The experimental phase diagram as a function of twist angle remains to be established. By comprehensive numerical study, we show that band mixing has large qualitative and quantitative effects on the energetics of competing states and their energy gaps throughout the twist angle range $\theta\leq 4^\circ$. This lays the ground for the detailed realistic study of a rich variety of strongly correlated twisted semiconductor multilayers and an understanding of the phase diagram of these fascinating systems.Comment: 5 + 2 pages, 7 Figure

The Mechanism behind Erosive Bursts in Porous Media

Erosion and deposition during flow through porous media can lead to large erosive bursts that manifest as jumps in permeability and pressure loss. Here we reveal that the cause of these bursts is the re-opening of clogged pores when the pressure difference between two opposite sites of the pore surpasses a certain threshold. We perform numerical simulations of flow through porous media and compare our predictions to experimental results, recovering with excellent agreement shape and power-law distribution of pressure loss jumps, and the behavior of the permeability jumps as function of particle concentration. Furthermore, we find that erosive bursts only occur for pressure gradient thresholds within the range of two critical values, independent on how the flow is driven. Our findings provide a better understanding of sudden sand production in oil wells and breakthrough in filtration.Comment: 7 pages, 8 figure

Negative Appendectomy Rate in Urban Referral Hospitals in Tanzania: A Cross-sectional Analysis of Associated Factors

Background: Acute appendicitis (AA) has a lifetime risk of 8.3% with a consequent 23% lifetime risk of emergency appendectomy. In atypical presentation, making a clinical diagnosis is difficult, leading to a high perforation rate (PR) or misdiagnoses and high negative appendectomy rates (NAR). This study aimed to establish NAR and explore the associated factors and possible attainable solutions to reduce it in urban referral hospitals in Tanzania. Methods: This was a crosssectional study with 91 consecutive patients, aged 10 years and older undergoing appendectomy for suspected AA with histological evaluation of specimens. The study was powered to detect the NAR at 95% confidence level and 80% power. Results: The histological NAR was 38.5% and the perforation rate was 25.3%. The Alvarado score (AS) was rarely applied (6%), despite a demonstrated ability in this study to decrease the NAR by half. Females were four times more likely to undergo negative appendectomy than males. Conclusion: The NAR is clinically significant as about two out of every five patients undergoing emergency appendectomy for suspected AA do not require the procedure. The AS is underutilized despite a demonstrated ability to decrease the NAR. We recommend that the AS be incorporated in the management of patients with suspected appendicitis

Algae personification toxicity by GC–MASS and treatment by using material potassium permanganate in exposed basin

AbstractThis study was conducted to address algal toxins using potassium permanganate through the control of biomass growth of algae under following conditions value 25±1 °C illumination intensity value 245microeinstein/m2/s, using the culture media Chu-10 Modified for the purpose of development algae. We treated algal toxins belonging to groups of Neurotoxins, Hepatotoxins, Pyriproxyfen, Emodin, Brevetoxins-10 (A) and Cytotoxins using concentrations of potassium permanganate represented by 2, 4, 8 and 16mg/l with alum concentration for each concentration of 30mg/l, as the removal rate reached to 100% of the toxin blooms in concentrations of 8 and 16mg/l respectively, through the examination of algal toxins mediated by GC–MASS compared to the standard, which diagnosed a range of algal toxins with C2H3C12NO formulas of synthetic C9H13NO2, C18H27NO3, C11H12N2O6, C11H17N3O, C10H17N3O, C9H15Br2NO, CH4N2O2, C11H17NO2, C13H9BrN2O3, C3H7NO4S, C20H29NO3, C15H10O5, C4H8O2 and C2H2Cl3NO the concentrations 2 and 4mg/l turned toxic compounds into non-toxic compounds represented by C7H6O2, C5H6N2O, C12H11ClO4, C6H6O2, C12H10O4, C10H17N, C4H6O2 and C5H6N2O. The results showed reduced primary productivity of algae chlorophyll a result of substance to stop chloroplast for vital activity through the influence of the concentration of potassium permanganate values 0.571, 1.142, 0.583 and 1.713mg/l respectively, compared to the standard of 114.2mg/l. As diagnosed types of Algae producing toxins are represented by Microcystis aeruginosa, Microcystis flosaquae, Oscillatoria amoena, Oscillatoria amphibian, Oscillatoria boryana, Oscillatoria limnetica, Oscillatoria perornata, Phormidium ambiguum, Lyngbya digueti, Lyngbya major, Lyngbya nordgaadii, Lyngbya spirulinoides, Nostoc carneum, Nostoc spongiforme, Anabaena augstumalis, Chroococcus indicus and Chroococcus minor, as the dry weight of live Algae producing toxins is 17.342g/l

Influences of powder morphology and spreading parameters on the powder bed topography uniformity in powder bed fusion metal additive manufacturing

Powder spreading is a crucial step in the powder bed fusion process, which controls the quality of powder bed and consequently affects the quality of printed parts. To date, however, powder spreadability has received very little attention and substantial fundamental work is still needed, largely because of the lack of experimental studies. Therefore, the focus of the present study addresses the influences of powder morphology, spreading velocity and layer thickness on the powder bed topography uniformity. The experiments were conducted with a laser powder bed fusion printer and the powder layers were spread systematically and comprehensively assessed. In summary, it was found that particle sphericity and surface texture dictates the degree of impact that the spreader velocity and the layer thickness exert on the quality of powder bed topography in spread layers. The spreader velocity has substantial influence on powder bed uniformity, such that better uniformity is achieved with low spreading velocities, ≤ 80 mm/s. Powders with a wide particle distribution and containing large number of fine particles (< 25 μm) enabled formation of uniform and dense powder beds, however such powders were found to be more affected by segregation. In addition to these observed effects, for the first time, the major process related challenges to powder spreadability and powder bed quality are reported in this study

Household sanitation and personal hygiene practices are associated with child stunting in rural India : a cross-sectional analysis of surveys

Policies and programming aimed at addressing child stunting should encompass water, sanitation and hygiene (WASH) interventions, shifting emphasis from nutrition-specific to nutrition-sensitive programming. Compared with open defecation, household access to a toilet facility was associated with 16–39% reduced odds of stunting among children aged 0–23 months. Household access to improved water supply was not in itself associated with stunting. The caregiver's self-reported practices of washing hands with soap before meals or after defecation were inversely associated with child stunting. However, the inverse association between reported personal hygiene practices and stunting was stronger among households with access to toilet facilities or piped water

USED OIL RECYCLING AND TREATMENT IN THE UNITED ARAB EMIRATES ECONOMICAL AND ENVIRONMENTAL ASSESSMENTS

In this work, we are investigating used oil recycling opportunities in United Arab Emirates. The economical assessment shows that it is worthy to recycle used oil. In the Emirate of Sharjah alone, recycling used oil could save $168,000 per year in fuel, or 250,000 gallons of base oil. The environmental assessment shows that more than 50% of used oil generated in the Emirate of Sharjah is not recorded. This is a serious problem that threatens our natural resources such as water and soil. Laboratory analysis of some properties of different classes of engine oils shows that recycling used oil could be pursued effectively

The path of least resistance: Paying for antibiotics in non-human uses

Antibiotic resistance is a critical threat to human and animal health. Despite the importance of antibiotics, regulators continue to allow antibiotics to be used in low-value applications - subtherapeutic dosing in animals, and spraying tobacco plants for blue mold, for example - where the benefits are unlikely to outweigh the costs in terms of increased resistance. We explore the application of a user fee in non-human uses of antibiotics. Such a fee would efficiently deter low value uses while also providing funding to support the development of the urgently needed new antibiotics