Interaction-tuned Anderson versus Mott localization

Disorder or sufficiently strong interactions can render a metallic state unstable causing it to turn into an insulating one. Despite the fact that the interplay of these two routes to a vanishing conductivity has been a central research topic, a unifying picture has not emerged so far. Here, we establish that the two-dimensional Falicov-Kimball model, one of the simplest lattice models of strong electron correlation does allow for the study of this interplay. In particular, we show that this model at particle-hole symmetry possesses three distinct thermodynamic insulating phases and exhibits Anderson localization. The previously reported metallic phase is identified as a finite-size feature due to the presence of weak localization. We characterize these phases by their electronic density of states, staggered occupation, conductivity, and the generalized inverse participation ratio. The implications of our findings for other strongly correlated systems are discussed.Comment: 5 pages, 4 figure

Impact of mechanical bowel preparation in elective colorectal surgery: a meta-analysis

AIM: To analyse the effect of mechanical bowel preparation vs no mechanical bowel preparation on outcome in patients undergoing elective colorectal surgery. METHODS: Meta-analysis of randomised controlled trials and observational studies comparing adult patients receiving mechanical bowel preparation with those receiving no mechanical bowel preparation, subdivided into those receiving a single rectal enema and those who received no preparation at all prior to elective colorectal surgery. RESULTS: A total of 36 studies (23 randomised controlled trials and 13 observational studies) including 21568 patients undergoing elective colorectal surgery were included. When all studies were considered, mechanical bowel preparation was not associated with any significant difference in anastomotic leak rates (OR = 0.90, 95%CI: 0.74 to 1.10, p = 0.32), surgical site infection (OR = 0.99, 95%CI: 0.80 to 1.24, p = 0.96), intraabdominal collection (OR = 0.86, 95%CI: 0.63 to 1.17, p = 0.34), mortality (OR = 0.85, 95%CI: 0.57 to 1.27, p = 0.43), reoperation (OR = 0.91, 95%CI: 0.75 to 1.12, p = 0.38) or hospital length of stay (overall mean difference 0.11 d, 95%CI: -0.51 to 0.73, p = 0.72), when compared with no mechanical bowel preparation, nor when evidence from just randomized controlled trials was analysed. A sub-analysis of mechanical bowel preparation vs absolutely no preparation or a single rectal enema similarly revealed no differences in clinical outcome measures. CONCLUSION: In the most comprehensive meta-analysis of mechanical bowel preparation in elective colorectal surgery to date, this study has suggested that the use of mechanical bowel preparation does not affect the incidence of postoperative complications when compared with no preparation. Hence, mechanical bowel preparation should not be administered routinely prior to elective colorectal surgery

A Computational Fluid Dynamics Investigation on the Drag Coefficient Measurement of an AUV in a Towing Tank

The accuracy of experimental procedure used to calculate the drag coefficient of an Autonomous underwater vehicle (AUV) in a towing tank is investigated using computational fluid dynamics. Effects of struts, used to connect the AUV model to towing carriage, on the hydrodynamics coefficient of the AUV at various relative submergence depths, at AUV speeds of 1.5 and 2.5 m/s are numerically simulated. Various numerical modeling are performed to investigate the effects of free surface with and without presence of struts on the drag coefficient of the AUV. Volume of fluid (VOF) model is used to solve the two phase flow RANS equations. The drag coefficients obtained from two phase flow simulations are compared with those obtained from single phase flow at corresponding velocities. The results obtained from experiments conducted in the towing tank of the Subsea Science and Technology centre, on a full-scale model of the AUV developed in this Centre, agreed well with those obtained by numerical simulations

Vermicompost Application in Different Intercropping Patterns Improves the Mineral Nutrient Uptake and Essential Oil Compositions of Sweet Basil (Ocimum basilicum L.)

Only a few studies have hitherto investigated the effects of the application of organic fertilizers in intercropping systems on the plant essential oil (EO) productivity. Hence, this work has aimed to study the effect of different intercropping patterns on EO quality and quantity of sweet basil (Ocimum basilicum L.) under vermicompost application. In the present study, the cropping patterns consisted of 1B:1CB, 2B:2CB, 3B:2CB, and 4B:2CB (basil: common bean) as well as the pure culture of both crops and fertilizer treatments including usage or non-usage of vermicompost. The maximum seed yield of common bean (2786 kg ha−1) and dry matter yield of basil in the first (261.5 g m−2) and second harvests (214.7 g m−2) were recorded in the pure cultures fertilized with vermicompost. In addition, the nutrient uptake rate of macronutrients and micronutrients in both plants after application of vermicompost improved in intercropping patterns. In both harvests, the maximum EO content of basil (0.84% in the first harvest and 0.69% in the second harvest) was observed at the cropping ratio of 3B:2CB fertilized with vermicompost. Chemical analysis, achieved by GC–MS, evidenced 1,8-cineole, linalool, methyl chavicol, α-trans-bergamotene, methyl eugenol, and epi-α-cadinol as the main basil EO constituents in both harvests. The highest increment level for most ofEO constituents, nutrient uptake, and land equivalent ratio (1.52) were obtained in the intercropping pattern of 3B:2CB fertilized with vermicompost. In general, the intercropping pattern of 3B:2CB after use of vermicompost can improve the EO productivity and quality of basil. This intercropping pattern was accompanied by the increment of nutrient uptake. Therefore, this treatment can be introduced as a valid and sustainable strategy to replace chemical fertilizer and plant monoculture

Hybrid photonic-bandgap accelerating cavities

In a recent investigation, we studied two-dimensional point-defected photonic bandgap cavities composed of dielectric rods arranged according to various representative periodic and aperiodic lattices, with special emphasis on possible applications to particle acceleration (along the longitudinal axis). In this paper, we present a new study aimed at highlighting the possible advantages of using hybrid structures based on the above dielectric configurations, but featuring metallic rods in the outermost regions, for the design of extremely-high quality factor, bandgap-based, accelerating resonators. In this framework, we consider diverse configurations, with different (periodic and aperiodic) lattice geometries, sizes, and dielectric/metal fractions. Moreover, we also explore possible improvements attainable via the use of superconducting plates to confine the electromagnetic field in the longitudinal direction. Results from our comparative studies, based on numerical full-wave simulations backed by experimental validations (at room and cryogenic temperatures) in the microwave region, identify the candidate parametric configurations capable of yielding the highest quality factor.Comment: 13 pages, 5 figures, 3 tables. One figure and one reference added; minor changes in the tex

The role of oral antibiotic preparation in elective colorectal surgery: a meta-analysis

© 2018 The Author(s). Published by Wolters Kluwer Health, Inc. Objectives:To compare the impact of the use of oral antibiotics (OAB) with or without mechanical bowel preparation (MBP) on outcome in elective colorectal surgery.Summary Background Data:Meta-analyses have demonstrated that MBP does not impact upon postoperative morbidity or mortality, and as such it should not be prescribed routinely. However, recent evidence from large retrospective cohort and database studies has suggested that there may be a role for combined OAB and MBP, or OAB alone in the prevention of surgical site infection (SSI).Methods:A meta-analysis of randomized controlled trials and cohort studies including adult patients undergoing elective colorectal surgery, receiving OAB with or without MBP was performed. The outcome measures examined were SSI, anastomotic leak, 30-day mortality, overall morbidity, development of ileus, reoperation and Clostridium difficile infection.Results:A total of 40 studies with 69,517 patients (28 randomized controlled trials, n = 6437 and 12 cohort studies, n = 63,080) were included. The combination of MBP+OAB versus MBP alone was associated with a significant reduction in SSI [risk ratio (RR) 0.51, 95% confidence interval (CI) 0.46-0.56, P < 0.00001, I2 = 13%], anastomotic leak (RR 0.62, 95% CI 0.55-0.70, P < 0.00001, I2 = 0%), 30-day mortality (RR 0.58, 95% CI 0.44-0.76, P < 0.0001, I2 = 0%), overall morbidity (RR 0.67, 95% CI 0.63-0.71, P < 0.00001, I2 = 0%), and development of ileus (RR 0.72, 95% CI 0.52-0.98, P = 0.04, I2 = 36%), with no difference in Clostridium difficile infection rates. When a combination of MBP+OAB was compared with OAB alone, no significant difference was seen in SSI or anastomotic leak rates, but there was a significant reduction in 30-day mortality, and incidence of postoperative ileus with the combination. There is minimal literature available on the comparison between combined MBP+OAB versus no preparation, OAB alone versus no preparation, and OAB versus MBP.Conclusions:Current evidence suggests a potentially significant role for OAB preparation, either in combination with MBP or alone, in the prevention of postoperative complications in elective colorectal surgery. Further high-quality evidence is required to differentiate between the benefits of combined MBP+OAB or OAB alone

Apple pomace powder as natural food ingredient in bakery jams

The aim of the present study was to investigate whether apple pomace powder produced by a simple drying method is suitable for replacing pectin in bakery jam products. Rheological properties of bakery jams were tested by oscillatory tests using amplitude sweep method. Apple pomace addition decreased gel strength and stability of bakery jams, while 12-month storage increased the gel strength of samples. Based on our results, dried apple pomace powder seems to be suitable to replace pectin up to 40% without changing rheological properties of bakery jams

Novel and emerging mutations of SARS-CoV-2: Biomedical implications

Coronavirus disease-19 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 virus strains has geographical diversity associated with diverse severity, mortality rate, and response to treatment that were characterized using phylogenetic network analysis of SARS-CoV-2 genomes. Although, there is no explicit and integrative explanation for these variations, the genetic arrangement, and stability of SARS-CoV-2 are basic contributing factors to its virulence and pathogenesis. Hence, understanding these features can be used to predict the future transmission dynamics of SARS-CoV-2 infection, drug development, and vaccine. In this review, we discuss the most recent findings on the mutations in the SARS-CoV-2, which provide valuable information on the genetic diversity of SARS-CoV-2, especially for DNA-based diagnosis, antivirals, and vaccine development for COVID-19. © 202

The relationship of air pollution and surrogate markers of endothelial dysfunction in a population-based sample of children

<p>Abstract</p> <p>Background</p> <p>This study aimed to assess the relationship of air pollution and plasma surrogate markers of endothelial dysfunction in the pediatric age group.</p> <p>Methods</p> <p>This cross-sectional study was conducted in 2009-2010 among 125 participants aged 10-18 years. They were randomly selected from different areas of Isfahan city, the second large and air-polluted city in Iran. The association of air pollutants' levels with serum thrombomodulin (TM) and tissue factor (TF) was determined after adjustment for age, gender, anthropometric measures, dietary and physical activity habits.</p> <p>Results</p> <p>Data of 118 participants was complete and was analyzed. The mean age was 12.79 (2.35) years. The mean pollution standards index (PSI) value was at moderate level, the mean particular matter measuring up to 10 μm (PM₁₀) was more than twice the normal level. Multiple linear regression analysis showed that TF had significant relationship with all air pollutants except than carbon monoxide, and TM had significant inverse relationship with ozone. The odds ratio of elevated TF was significantly higher in the upper vs. the lowest quartiles of PM₁₀, ozone and PSI. The corresponding figures were in opposite direction for TM.</p> <p>Conclusions</p> <p>The relationship of air pollutants with endothelial dysfunction and pro-coagulant state can be an important factor in the development of atherosclerosis from early life. This finding should be confirmed in future longitudinal studies. Concerns about the harmful effects of air pollution on children's health should be considered a top priority for public health policy; it should be underscored in primordial and primary prevention of chronic diseases.</p