618 research outputs found

    Intermittency in Two-Dimensional Turbulence with Drag

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    We consider the enstrophy cascade in forced two-dimensional turbulence with a linear drag force. In the presence of linear drag, the energy wavenumber spectrum drops with a power law faster than in the case without drag, and the vorticity field becomes intermittent, as shown by the anomalous scaling of the vorticity structure functions. Using a previous theory, we compare numerical simulation results with predictions for the power law exponent of the energy wavenumber spectrum and the scaling exponents of the vorticity structure functions ζ2q\zeta_{2q} obtained in terms of the distribution of finite time Lyapunov exponents. We also study, both by numerical experiment and theoretical analysis, the multifractal structure of the viscous enstrophy dissipation in terms of its R\'{e}nyi dimension spectrum DqD_q and singularity spectrum f(α)f(\alpha). We derive a relation between DqD_q and ζ2q\zeta_{2q}, and discuss its relevance to a version of the refined similarity hypothesis. In addition, we obtain and compare theoretically and numerically derived results for the dependence on separation rr of the probability distribution of \delta_{\V{r}}\omega, the difference between the vorticity at two points separated by a distance rr. Our numerical simulations are done on a 4096×40964096 \times 4096 grid.Comment: 18 pages, 17 figure

    Persistence Wins: Long-Term Agricultural Conservation Outreach Pays Off

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    This article discusses the lesson learned from an Extension, state, and federal agency coordinated water quality project that was formally started in 1995. In the project, educational programing was provided, high risk areas were identified, and BMPs were implemented on these areas. The net result of BMP implementation was a 38% improvement in South Dakota Bad River water quality. This improvement was attributed to Extension and others providing leadership on: 1) the development of local learning communities and 2) identification and implementing BMP\u27s in high risk areas. This work demonstrates that Extension can make a difference

    Copper-induced conformational change in a marsupial prion protein repeat peptide probed using FTIR spectroscopy

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    AbstractWe report the first Fourier transform infrared analysis of prion protein (PrP) repeats and the first study of PrP repeats of marsupial origin. Large changes in the secondary structure and an increase in hydrogen bonding within the peptide groups were evident from a red shift of the amide I band by >7 cm−1 and an approximately five-fold reduction in amide hydrogen–deuterium exchange for peptide interacting with Cu2+ ions. Changes in the tertiary structure upon copper binding were also evident from the appearance of a new band at 1564 cm−1, which arises from the ring vibration of histidine. The copper-induced conformational change is pH dependent, and occurs at pH >7

    N,N′-Bis[3,5-bis­(2,6-diisopropyl­phen­yl)phen­yl]butane-2,3-diimine

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    The title mol­ecule, C64H80N2, lies on an inversion center wherein the central butane­diimine fragment [N=C(Me)—C(Me)=N] is essentially planar [maximum deviation = 0.002 (2) Å] and its mean plane forms a dihedral of 70.88 (10)° with the attached benzene ring. In the symmetry-unique part of the mol­ecule, the dihedral angles between the benzene ring bonded to the N atom and the other two benzene rings are 89.61 (6) and 82.77 (6)°

    (2R,3aR,4S,7R,7aS,9R,10aR,11S,14R,14aS)-rel-3a,4,7,7a,10a,11,14,14aOctahydro-4,14:7,11-diepoxy-2,9propanonaphtho[1,2-f:5,6-f000]diisoindole1,3,8,10-tetrone (9CI): a cyclophane derived from naphtho[1,2-c:5,6-c]difuran

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    Sherpa Romeo green journal. Open access article. Creative Commons Attribution License (CC BY) applies.The title compound, C25H18N2O6, is a naphthalenophane styled in the manner of Warrener's alicyclic cyclo­phanes or mol­ecular racks wherein a trimethyl­ene tether is perfectly staggered between the two N atoms such that the central methyl­ene H atoms point toward the naphthalene [pi]-system. The dihedral angle between the mean planes of the two benzene rings is 7.61 (7)°.Ye

    The effects of yogurt supplementation and nutritional education on malnourished infants : a pilot RCT in Dhaka's slums

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    Our objective was to quantify the effects of yogurt supplementation and nutrition education over three months on the linear growth of infants at risk of stunting. We conducted a three-arm pilot randomized controlled trial: (1) nutrition education for mothers; (2) nutrition education plus a daily yogurt supplement (50 g) for the index child; and (3) usual care (control). Dyads of children aged 4–6 months and at risk of stunting [length-for-age z-score (LAZ) ≤ −1 SD and >−2 SD] and their mothers with ≤10 years of education were eligible for the study. Participants were recruited from five slum areas in Dhaka, Bangladesh. Intention-to-treat (N = 162) and complete-case analyses (N = 127) showed no between-group statistically significant differences in LAZ or weight-for-age (WAZ). However, the yogurt group showed greater change in linear growth compared to the control (LAZ: mean difference 0.20, 95% CI: −0.06, 0.47, p-value 0.13), which was also slightly greater than the education-only group. Children in the yogurt plus group were five times (95% CI: 0.80, 31.80, p-value 0.09) more likely to meet the minimum dietary diversity (MDD) score compared to the control. A 3-month follow-up of this pilot study did not demonstrate that yogurt was beneficial to linear growth. However, there were encouraging trends that merit replication of the intervention with larger samples and longer follow-ups

    Raman Fingerprints of Graphene Produced by Anodic Electrochemical Exfoliation

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    Electrochemical exfoliation is one of the most promising methods for scalable production of graphene. However, limited understanding of its Raman spectrum as well as lack of measurement standards for graphene strongly limit its industrial applications. In this work we show a systematic study of the Raman spectrum of electrochemically exfoliated graphene, produced using different electrolytes and different types of solvents in varying amounts. We demonstrate that no information on the thickness can be extracted from the shape of the 2D peak as this type of graphene is defective. Furthermore, the number of defects and the uniformity of the samples strongly depend on the experimental conditions, including post-processing. Under specific conditions, formation of short conductive trans-polyacetylene chains has been observed. Our Raman analysis provides guidance for the community on how to get information on defects coming from electrolyte, temperature and other experimental conditions, by making Raman spectroscopy a powerful metrology tool.Comment: This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Nano Letters, American Chemical Society after peer review. To access the final edited and published work, included the SI, see DOI: 10.1021/acs.nanolett.0c0033

    New Phases in the Mg-Al-Sr System

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    Abstract. This work presents experimental investigation of 14 different alloys with differential scanning calorimetery (DSC), scanning electron microscopy/energy dispersive spectrometer (SEM/EDS) analysis, quantitative electron probe micro-analysis (EPMA) and X-ray diffraction (XRD) techniques to identify the phases in the Mg-Al-Sr system and to determine their compositions. DSC has permitted real time measurement of the phase changes involved in these systems. The temperature ranges for the phase transformations and enthalpy of melting and enthalpy of formation of the compounds are reported. Comparison between these results and the thermodynamic findings has been discussed. The microstructure of the Mg-Al-Sr-based alloys is primarily dominated by (Mg) and (Al 4 Sr). The plate-like structure has been identified as Al 4 Sr. A new ternary intermetallic with chemical composition of 69.9 ± 1.5 at.% magnesium, 19.3 ± 2.0 at.% aluminum and 8.7 ± 0.6 at.% strontium has been identified in three different alloys. This phase was characterized as a large precipitate. Three ternary solid solutions have been observed. The solubility ranges of Al in Mg 38 Sr 9 and Mg 17 Sr 2 are 12.5 and 8.5 at.%, respectively, whereas the solubility of Mg in Al 4 Sr compound is found to be 23 at.% in the investigated samples. Further, Mg was found to dissolve 11.4 at.% Al at room temperature

    Impact of COVID-19 on Children and Young Adults With Type 2 Diabetes: A Narrative Review With Emphasis on the Potential of Intermittent Fasting as a Preventive Strategy

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    open access articleBackground: The world is still struggling to control the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The level of uncertainty regarding the virus is still significantly high. The virus behaves differently in children and young adults. Most children and adolescents are either asymptomatic or have mild symptoms. They generally have a very good prognosis. However, it is not well known whether children and young adults with type 2 diabetes are at risk of getting a severe infection of COVID-19 or not as it has only been reported among adults with diabetes. Many children with type 2 diabetes have been performing dawn to dusk fasting during the month of Ramadan, before and during the COVID-19 pandemic, and the impact of this on their health has not been well investigated. Previous studies with adults have suggested that intermittent fasting may be beneficial in different ways including reversal of type 2 diabetes and prevention of COVID-19 infection. Objective: The primary aim of this narrative review is to summarise the impacts of the COVID-19 pandemic on children and young adults with type 2 diabetes, and to identify the knowledge gaps in the literature. It also explores the importance of intermittent fasting in reversing the pathogenesis of diabetes and highlighting the effects of Ramadan fasting on these patients. Methods: This narrative review has been produced by examining several databases, including Google Scholar, Research Gate, PubMed, Cochrane Library, MEDLINE (EBSCO), and Web of Science. The most common search terms used were “COVID-19 AND Children”, “SARS-CoV-2 AND/OR Children”, “COVID-19 AND Diabetes” “COVID-19 Epidemiology”, “COVID-19 AND Ramadan fasting”, “COVID-19 and Intermittent fasting”. All the resources used are either peer-reviewed articles/reports and/or official websites, such as the BBC and GOV.UK. Results: Having reviewed the currently limited evidence, it has been found that the incidence of COVID-19 among children with type 2 diabetes seems to be not much different from children without diabetes. However, these patients are still vulnerable to any infection. Several studies have reported that prevention programmes such as intermittent fasting are effective to protect these groups of patients from developing any complications. Moreover, observing Ramadan fasting could be beneficial for some children with established diabetes and people at risk. Conclusion: Children and young adults with type 2 diabetes are not at risk of severe COVID-19 infection as the case in adults with diabetes. More research is needed to identify the impact of COVID-19 and to investigate the efficacy and safety of intermittent fasting, including Ramadan fasting, among these age groups. Implementing these cost-effective programmes may have a great impact in minimising the incidence of diabetes among these age groups during the current pandemic

    Water Manganese Exposure and Children’s Intellectual Function in Araihazar, Bangladesh

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    Exposure to manganese via inhalation has long been known to elicit neurotoxicity in adults, but little is known about possible consequences of exposure via drinking water. In this study, we report results of a cross-sectional investigation of intellectual function in 142 10-year-old children in Araihazar, Bangladesh, who had been consuming tube-well water with an average concentration of 793 μg Mn/L and 3 μg arsenic/L. Children and mothers came to our field clinic, where children received a medical examination in which weight, height, and head circumference were measured. Children’s intellectual function was assessed on tests drawn from the Wechsler Intelligence Scale for Children, version III, by summing weighted items across domains to create Verbal, Performance, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and creatinine and were asked to provide blood samples for measuring blood lead, As, Mn, and hemoglobin concentrations. After adjustment for sociodemographic covariates, water Mn was associated with reduced Full-Scale, Performance, and Verbal raw scores, in a dose–response fashion; the low level of As in water had no effect. In the United States, roughly 6% of domestic household wells have Mn concentrations that exceed 300 μg Mn/L, the current U.S. Environmental Protection Agency lifetime health advisory level. We conclude that in both Bangladesh and the United States, some children are at risk for Mn-induced neurotoxicity
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