A proposed neutral line signature

An identifying signature is proposed for the existence and location of the neutral line in the magnetotail. The signature, abrupt density, and temperature changes in the Earthtail direction, was first discovered in test particle simulations. Such temperature variations have been observed in ISEE data (Huang et. al. 1992), but their connection to the possible existence of a neutral line in the tail has not yet been established. The proposed signature develops earlier than the ion velocity space ridge of Martin and Speiser (1988), but can only be seen by spacecraft in the vicinity of the neutral line, while the latter can locate a neutral line remotely

Origin of Lagrangian Intermittency in Drift-Wave Turbulence

The Lagrangian velocity statistics of dissipative drift-wave turbulence are investigated. For large values of the adiabaticity (or small collisionality), the probability density function of the Lagrangian acceleration shows exponential tails, as opposed to the stretched exponential or algebraic tails, generally observed for the highly intermittent acceleration of Navier-Stokes turbulence. This exponential distribution is shown to be a robust feature independent of the Reynolds number. For small adiabaticity, algebraic tails are observed, suggesting the strong influence of point-vortex-like dynamics on the acceleration. A causal connection is found between the shape of the probability density function and the autocorrelation of the norm of the acceleration

A Near-Deterministic Mutational Hotspot in Pseudomonas fluorescens Is Constructed by Multiple Interacting Genomic Features

Mutation—whilst stochastic—is frequently biased toward certain loci. When combined with selection, this results in highly repeatable and predictable evolutionary outcomes. Immotile variants of the bacterium Pseudomonas fluorescens (SBW25) possess a “mutational hotspot” that facilitates repeated occurrences of an identical de novo single nucleotide polymorphism when re-evolving motility, where ≥95% independent lines fix the mutation ntrB A289C. Identifying hotspots of similar potency in other genes and genomic backgrounds would prove valuable for predictive evolutionary models but to do so we must understand the genomic features that enable such a hotspot to form. Here, we reveal that genomic location, local nucleotide sequence, gene strandedness, and presence of mismatch repair proteins operate in combination to facilitate the formation of this mutational hotspot. Our study therefore provides a framework for utilizing genomic features to predict and identify hotspot positions capable of enforcing near-deterministic evolution

Field Measurement of Soil Surface Chemical Transport Properties for Comparison of Management Zones

Management of chemicals in soil is important, yet the complexity of field soils limits prediction of management effects on transport. To date, few methods have been available for field measurement of chemical transport properties, but a recently developed dripper–time domain reflectometry technique allows rapid collection of data for determining these properties. The objective of this work was to apply this technique for comparison of chemical transport properties for different soil management zones. Experiments were conducted comparing four interrow management zones: no-till nontrafficked, no-till trafficked, chisel plow nontrafficked, and chisel plow trafficked. Drip emitters were positioned at 12 locations in each zone and used to apply water followed by a step input of CaCl2 tracer solution. Breakthrough curves were measured via electrical conductivity with time domain reflectometry probes. The mobile–immobile model was fit to the breakthrough curves to determine chemical transport properties. Mean chemical transport properties were 0.34, 0.11 h−1, 10 cm h−1, 164 cm2 h−1, and 5 cm, for the immobile water fraction, mass exchange coefficient, average pore-water velocity, mobile dispersion coefficient, and dispersivity, respectively. All five properties showed significant differences between management zones. Differences in mass exchange and mobile dispersion coefficients coincided with differences in tillage, while differences in mean pore water velocities coincided with differences in traffic. The immobile water fraction was largest for the no-till nontrafficked zone. These results represent one of very few reports for field measurement of chemical transport properties and the first application of this approach for comparison of chemical transport properties across management zones

Soil water retention and hydraulic conductivity dynamics following tillage

Soil bulk density (ρb) may be purposely reduced in agricultural fields using tillage to improve hydraulic properties. However, tillage alters the soil structure, resulting in unstable soils. As the soil stabilizes, ρb increases over time. While this is known, studies on soil hydraulic properties in tilled soils, including comparisons between tilled and non-tilled soils, commonly assume a rigid soil structure. This study presents changes in soil water retention and saturated hydraulic conductivity (Ksat) as ρb increased dynamically with time following tillage at a loam-textured field site. Over the summer of 2015, soil cores were collected at several depths below the surface following precipitation events. Soil water retention curves and Ksat were determined using pressure cells and the constant head method, respectively. Tillage reduced ρb to 0.94 g cm−3. Changes in ρb increased with depth, reaching a ρb of 1.11 g cm−3 in the 0–5 cm layer, and a ρb of 1.42 g cm−3 at the deepest tilled layer. Soil water retention curves were markedly steeper for samples with higher ρb, indicating an overall increase in water retained at a soil matric potential (Ψ) of −33 kPa. Evaluation of two modeling approaches for water retention as a function ρbindicated that changes in water retention with increases in ρb could be reasonably estimated if a matching point was used. No clear relationship between Ksat and ρbwas obvious for ρb \u3c 1.06 cm3 cm−3, but for ρb \u3e 1.06 cm3 cm−3, Ksat decreased markedly (order of magnitude) as ρb increased. Hydraulic properties varied strongly depending on time since tillage and soil depth, and results have implications for models of tilled soils, as well as for studies comparing tilled and non-tilled soils

Remote Monitoring of Fish in Small Streams: A Unified Approach Using Pit Tags

Accurate assessments of fish populations are often limited by re-observation or recapture events. Since the early 1990s, passive integrated transponders (PIT tags) have been used to understand the biology of many fish species. Until recently, PIT applications in small streams have been limited to physical recapture events. To maximize recapture probability, we constructed PIT antenna arrays in small streams to remotely detect individual fish. Experiences from two different laboratories (three case studies) allowed us to develop a unified approach to applying PIT technology for enhancing data assessments. Information on equipment, its installation, tag considerations, and array construction is provided. Theoretical and practical definitions are introduced to standardize metrics for assessing detection efficiency. We demonstrate how certain conditions (stream discharge, vibration, and ambient radio frequency noise) affect the detection efficiency and suggest that by monitoring these conditions, expectations of efficiency can be modified. We emphasize the importance of consistently estimating detection efficiency for fisheries applications

Comorbidities and Treatments in United States Youth with Chronic Musculoskeletal Pain

Introduction: Chronic musculoskeletal (MSK) pain has been associated with chronic illnesses and high rates of pain medication use, often in referral centers, European populations, or studies focused on single drug classes. We aimed to characterize patterns of comorbidities and treatments associated with chronic MSK pain in a nationally-representative sample of US youth. Methods: We used the National Ambulatory Medical Care Survey (2002-2015) and National Hospital Ambulatory Medical Care Survey (2002-2011), which contain cross-sectional data for US outpatient visits. The study included all visits for youth age 8-24, excluding those with malignancy or sickle cell disease. We compared comorbidities and drugs ordered in visits for chronic MSK pain with (1) visits for any reason besides MSK pain and (2) visits for acute MSK pain, using chi-square tests and logistic regression, adjusting for several covariates. Results: Chronic non-psychiatric diseases were more common among visits for chronic MSK pain (32.0%) in comparison to both visits for acute MSK pain (17.9%) and visits for other reasons (18.8%). Nonsteroidal anti-inflammatories were less commonly ordered at visits for chronic MSK pain in comparison to acute MSK pain (adjusted odds ratio [aOR]: 0.63, 95% CI 0.50-0.80). Opioids, gabapentinoids, and alternative medicine were each ordered more commonly at visits for chronic MSK pain in comparison to visits for acute MSK pain and other visits. Conclusion: US youth with chronic MSK were more likely to have chronic non-psychiatric medical conditions compared to youth without pain. Additionally, opioids, gabapentinoids, and alternative medicine were ordered more often in chronic MSK visits, which warrants further study

Strengthening NHS management and leadership : priorities for reform

Good management is key to the NHS’s ability to provide high-quality services and to maximise the impact of its resources in the face of growing demand for care. However, in recent years, the importance of good management has been somewhat forgotten in the policy debate at the expense of a focus on leadership.As part of the Health Foundation’s research on management in the health service, we interviewed NHS managers and leaders in England to understand the challenges they face, what works well and what could be done differently. In this long read, we set out some of the insights from these interviews, focusing mainly on the role and practice of managers, and how they are trained and supported.This coincides with government commissioning a review of leadership in health and social care in England, led by Sir Gordon Messenger, which is expected to report to the Secretary of State for Health and Social Care at the end of March. Here, we conclude with a series of recommendations for the Messenger review to consider, focused around the need to: better support providers and systems to tackle variation in management practice; improve access to training and development opportunities; ensure training equips managers and leaders with the skills they need today; tackle the reporting burden facing managers, and ensure the role of managers and leaders is better understood and valued. Arguing that we should better value NHS managers and leaders, and increase the support available to them, might not be the most politically popular case. But it is the right thing to do, and indeed will be essential if the NHS is to improve the quality and efficiency of its services as it recovers from the COVID-19 pandemic