167 research outputs found

    Pair Correlations, Short Range Order and Dispersive Excitations in the Quasi-Kagome Quantum Magnet Volborthite

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    We present spatial and dynamic information on the s=1/2 distorted kagome antiferromagnet volborthite, Cu3V2O7(OD)2.2D2O, obtained by polarized and inelastic neutron scattering. The instantaneous structure factor, S(Q), is dominated by nearest neighbor pair correlations, with short range order at wave vectors Q1=0.65(3) {\AA}^-1 and Q2=1.15(5) {\AA}^-1 emerging below 5 K. The excitation spectrum, S(Q,{\omega}), reveals two steep branches dispersing from Q1 and Q2, and a flat mode at {\omega}=5.0(2) meV. The results allow us to identify the cross-over at T*=1 K in 51V NMR and specific heat measurements as the build-up of correlations at Q_1. We compare our data to theoretical models proposed for volborthite, and demonstrate that the excitation spectrum can be explained by spin-wave-like excitations with anisotropic exchange parameters, as also suggested by recent local density calculations.Comment: Rewritten article resubmitted to Phys. Rev. Lett. 021

    Evaluation of an educational training on telehelath utilization rates and hospital readmissions in a home health setting.

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    Background: Hospital readmissions are on the rise and continue to be a concern within healthcare due to their effects on the quality of care and healthcare costs. Telehealth strategies have been utilized across healthcare settings to improve hospital readmission rates. Purpose: The purpose of this project was to evaluate the effectiveness of a telehealth training program in increasing telehealth utilization rates and reducing the acute care hospitalization rate within a single home health agency. Intervention: A 30-minute PowerPoint presentation on the definition of telehealth, goals, and benefits of telehealth, patient eligibility, special considerations for clinicians, billing and coding guidelines, documentation requirements, discussion with patients on telehealth usage, role-playing exercises, and a mock telehealth visit was conducted for all field clinicians after the mandatory patient care conference. Following the education session, an eight-month evaluation was completed to compare telehealth enrollment, utilization, and hospital readmission rates before and after the training. Results: Telehealth enrollment significantly increased over the eight-month evaluation period, indicated by an increase from zero to 39 patients enrolled. The 60-day ACH rate decreased from 25.4% to 14.2% during the evaluation period, reaching statistical significance (p\u3c.001) Discussion: Implementing telehealth training is an effective way to increase telehealth utilization rates and decrease ACH rates within a home health setting

    Parental perceptions of bladder dysfunction in children with symptomatic joint hypermobility

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    Children with symptomatic joint hypermobility (SJH) report chronic pain, fatigue, and joint instability as their main symptoms. Symptoms can extend beyond musculoskeletal and include lower urinary tract dysfunction (LUTD). There are no studies exploring parent-perceived quality of life (QoL) in children with LUTD, or strategies used to manage symptoms in this population. Our online cross-sectional survey assessed parents of 6–18-year-olds via two UK charitable organizations. It included the Pediatric Incontinence Questionnaire (PinQ), the Dysfunctional Voiding Symptom Score, and questions exploring treatments and efficacy. Sixty-seven parental questionnaires were analyzed. The majority of children were white females (95%, n = 64). Urgency (97%, n = 65) and enuresis (41.7%, n = 28) were the most frequently reported symptoms. The PinQ questionnaire showed that children were emotionally distressed by LUTD. Twenty-nine parents (43%, n = 29) reported pharmacotherapy as the most effective treatment. Few had accessed other treatments such as physiotherapy (16%, n = 18). Most parents reported that overall treatment did not meet their expectations. This study highlights that parents perceive LUTD as having a great impact on their child's QoL. There is need for education among clinicians about LUTD and hypermobility-related disorders, and for development and evaluation of treatments

    The influence of poultry litter biochar on early season cotton growth

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    Cotton is known for being sensitive to cool, wet soils, especially in the early stages of growth. Amendments to soil can aid cotton seedlings in development and nutrient uptake. However, soil amendments can be costly and detrimental to the environment, and alternatives such as the addition of biochar have been considered. Biochar is produced from biomass that has gone through pyrolysis and has been shown to improve plant yield, microbial response, soil structure, soil cation–exchange capacity, and water use efficiency. This study was conducted to evaluate the effect of biochar on early season cotton growth. The aim of this study was to determine whether biochar aids nutrient uptake and seedling development during the seedling’s life cycle. The study was established in October 2013 in the greenhouse at the University of Arkansas using a randomized complete block design with three replications. Treatments included a control with no fertilizer or biochar, a control with fertilizer (56 kg N/ ha) and no biochar, and two fertilizer treatments (0 or 56 kg N/ ha) each with 1500 or 3000 kg/ha biochar. Plants were grown for eight weeks then harvested to collect plant height, plant fresh weight, plant dry weight, and leaf area. Data showed that the highest level of biochar with additional fertilizer provided the best growth response in plant height, fresh weight dry weight, and leaf area at 27.52 cm, 14.7g, 1.87 g, and 419.48 cm2 , respectively

    Her9/Hes4 Is Required for Retinal Photoreceptor Development, Maintenance, and Survival

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    The intrinsic and extrinsic factors that regulate vertebrate photoreceptor specification and differentiation are complex, and our understanding of all the players is far from complete. Her9, the zebrafish ortholog of human HES4, is a basic helix-loop-helix-orange transcriptional repressor that regulates neurogenesis in several developmental contexts. We have previously shown that her9 is upregulated during chronic rod photoreceptor degeneration and regeneration in adult zebrafish, but little is known about the role of her9 during retinal development. To better understand the function of Her9 in the retina, we generated zebrafish her9 CRISPR mutants. Her9 homozygous mutants displayed striking retinal phenotypes, including decreased numbers of rods and red/green cones, whereas blue and UV cones were relatively unaffected. The reduction in rods and red/green cones correlated with defects in photoreceptor subtype lineage specification. The remaining rods and double cones displayed abnormal outer segments, and elevated levels of apoptosis. In addition to the photoreceptor defects, her9 mutants also possessed a reduced proliferative ciliary marginal zone, and decreased and disorganized Müller glia. Mutation of her9 was larval lethal, with no mutants surviving past 13 days post fertilization. Our results reveal a previously undescribed role for Her9/Hes4 in photoreceptor differentiation, maintenance, and survival

    Complex magnetic ordering behavior in the frustrated perovskite Ba2MnMoO6

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    New and exotic ground states of magnetic materials are highly sought after and are extensively studied for the insights they provide into the thermodynamics of disorder and fundamental magnetic interactions. By controlling the crystal structure of an appropriate magnetic lattice, it is possible to cause the strong magnetic exchange interactions to sum to zero and so be frustrated. Due to the presence of this frustration, the lowest energy configuration that results may be crucially dependent on the tiniest of energy differences between a multitude of states that have (almost) the same energy. The keen interest in these materials arises from the fact that these finely balanced systems offer a way of probing classical or quantum mechanical interactions that are of fundamental importance but are too weak to be observed in non-frustrated systems. Here, we combine local and crystallographic probes of the cation-ordered double perovskite Ba2MnMoO6 that contains a face-centered cubic lattice of S = 5/2 Mn2+ cations. Neutron diffraction measurements below 9.27(7) K indicate that a fourfold degenerate non-collinear antiferromagnetic state exists with almost complete ordering of the Mn2+ spins. Muon spin relaxation measurements provide a local probe of the magnetic fields inside this material over the t1/2 = 2.2 µs lifetime of a muon, indicating a slightly lower Néel transition temperature of 7.9(1) K. The dc susceptibility data do not show the loss of magnetization that should accompany the onset of the antiferromagnetic order; they indicate that a strongly antiferromagnetically coupled paramagnetic state [θ = −73(3) K] persists down to 4 K, at which temperature a weak transition occurs. The behavior of this material differs considerably from the closely related compositions Ba2MnMO6 (M = W, Te), which show collinear ordering arrangements and well defined antiferromagnetic transitions in the bulk susceptibility. This suggests that the Mo6+ cation leads to a fine balance between the nearest and next-nearest neighbor superexchange in these frustrated double perovskite structures

    Evaluation of the 2010 Toyota Prius Hybrid Synergy Drive System

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    Subsystems of the 2010 Toyota Prius hybrid electric vehicle (HEV) were studied and tested as part of an intensive benchmarking effort carried out to produce detailed information concerning the current state of nondomestic alternative vehicle technologies. Feedback provided by benchmarking efforts is particularly useful to partners of the Vehicle Technologies collaborative research program as it is essential in establishing reasonable yet challenging programmatic goals which facilitate development of competitive technologies. The competitive nature set forth by the Vehicle Technologies Program (VTP) not only promotes energy independence and economic stability, it also advocates the advancement of alternative vehicle technologies in an overall global perspective. These technologies greatly facilitate the potential to reduce dependency on depleting natural resources and mitigate harmful impacts of transportation upon the environment
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