Spatial and Temporal Patterns of Small-Scale Mixing in Drake Passage

Temperature and salinity profiles obtained with expendable CTD probes throughout Drake Passage between February 2002 and July 2005 are analyzed to estimate turbulent diapycnal eddy diffusivities to a depth of 1000 m. Diffusivity values are inferred from density/temperature inversions and internal wave vertical strain. Both methods reveal the same pattern of spatial variability across Drake Passage; diffusivity estimates from inversions exceed those from vertical strain by a factor of 3 over most of Drake Passage. The Polar Front (PF) separates two dynamically different regions. Strong thermohaline intrusions characterize profiles obtained north of the PF. South of the PF, stratification is determined largely by salinity, and temperature is typically unstably stratified between 100- and 600-m depth. In the upper 400 m, turbulent diapycnal diffusivities are O(10^(−3) m2 s^(−1)) north of the PF but decrease to O(10^(−4) m2 s^(−1)) or smaller south of the PF. Below 400 m diffusivities typically exceed 10^(−4) m^2 s^(−1). Diffusivities decay weakly with depth north of the PF, whereas diffusivities increase with depth and peak near the local temperature maximum south of the PF. The meridional pattern in near-surface mixing corresponds to local maxima and minima of both wind stress and wind stress variance. Near-surface diffusivities are also found to be larger during winter months north of the PF. Wind-driven near-inertial waves, strong mesoscale eddy activity, and double-diffusive convection are suggested as possible factors contributing to observed mixing pattern

Hydrogeomorphic Factors and Ecosystem Responses in Coastal Wetlands of the Great Lakes

Gauging the impact of manipulative activities, such as rehabilitation or management, on wetlands requires having a notion of the unmanipulated condition as a reference. An understanding of the reference condition requires knowledge of dominant factors influencing ecosystem processes and biological communities. In this paper, we focus on natural physical factors (conditions and processes) that drive coastal wetland ecosystems of the Laurentian Great Lakes. Great Lakes coastal wetlands develop under conditions of largelake hydrology and disturbance imposed at a hierarchy of spatial and temporal scales and contain biotic communities adapted to unstable and unpredictable conditions. Coastal wetlands are configured along a continuum of hydrogeomorphic types: open coastal wetlands, drowned river mouth and Hooded delta wetlands, and protected wetlands, each developing distinct ecosystem properties and biotic communities. Hydrogeomorphic factors associated with the lake and watershed operate at a hierarchy of scales: a) local and short-term (seiches and ice action), b) watershed /lakewide /annual (seasonal water- level change), and c) larger or year-to-year and longer (regional and/or greater than one-year). Other physical factors include the unique water quality features of each lake. The aim of this paper is to provide scientists and managers with a framework for considering regional and site-specific geomorphometry and a hierarchy of physical processes in planning management and conservation projects

Journey Towards Recovery Following Physical Trauma

Convalescence and recovery following illness are of central importance to nursing. These themes have been explored increasingly in the literature. The focus, however, has been primarily on the process of integrating chronic illness into one’s life. Recovery from physical injury is rarely addressed. A body of work focusing on physical trauma demonstrates that recovery is often not complete after injuries that have not been viewed as disabling. To illuminate understanding of recovery following physical trauma, the purpose of our 1997 study was to describe more thoroughly the nature of recovery. A total of 63 adults, in a convenience sample, who survived serious physical trauma, were interviewed 2·5 years after injury using an open-ended semistructured interview guide. Three themes were identified: event, fallout, and moving-on. These themes provided the organizing structure for exploring the journey to recovery. This journey, as disclosed by the seriously injured, does not necessarily correspond with the views of most trauma clinicians. Traumatic events create a line of demarcation, separating lives into before and after. The event becomes the starting point of a journey to resume one’s life. The event itself is more than the trauma; it is the perceptual and contextual experience that needs to be incorporated into a person’s essence. Fallout from the injury is multifaceted and includes physical, psychological, social, and spiritual dimensions. Moving-on in this journey is nonlinear as survivors recognize their lives are forever different. The survivors’ accounts suggest that nurses should carefully consider the question, ‘What is successful recovery?

Preliminary Validation of a Mobility Obstacle Course for Persons with Mobility Impairment

The purpose of this study was to assess the reliability and validity of a mobility obstacle course for women with mobility impairments. Participants included 72 adult women with permanent physical disabilities including arthritis, orthopedic conditions, paraplegia, and others. The 60-m course consisted of carpeted runways and turns, ramps, a doorway, a transfer, and object manipulation. Participants completed two trials, walking or wheeling through the course as quickly as possible, safely and without running. Total course time and peak heart rate data were correlated with SF-36 health survey subscales. Overall, peak heart rate was significantly (p \u3c .05) correlated with physical functioning (r = -.328), limitations due to physical functioning (r = .261), and pain (r = .296). Total course time was significantly correlated with physical functioning. These findings indicate very high reliability and preliminary evidence of validity

Yeast Pro- and Paraprobiotics Have the Capability to Bind Pathogenic Bacteria Associated With Animal Disease

Live yeast probiotics and yeast cell wall components (paraprobiotics) may serve as an alternative to the use of antibiotics in prevention and treatment of infections caused by pathogenic bacteria. Probiotics and paraprobiotics can bind directly to pathogens, which limits binding of the pathogens to the intestinal cells and also facilitates removal from the host. However, knowledge of bacterial binding, specificity, and/or capability is limited with regard to probiotics or paraprobiotics. The goal of this study was to characterize the qualitative and quantitative nature of two Saccharomyces cerevisiae probiotics and three S. cerevisiae paraprobiotics to adhere to thirteen different pathogenic bacteria using scanning electron miscroscopy and filtration assays. On average, the yeast probiotics (LYA and LYB) exhibited overall greater (P \u3c 0.05) adhesion to the pathogenic bacteria tested (41% and 34%) in comparison to paraprobiotics (23%, 21%, and 22%), though variations were observed between pathogens tested. The ability of Salmonella and Listeriato utilize components of the yeast as a nutrient source was also tested. Bacteria were cultured in media with limited carbon and supplemented with cell free extracts of the probiotics and paraprobiotics. Salmonella exhibited growth, indicating these pathogens could utilize the yeast lysates as a carbon source. Listeria monocytogenes had limited growth in only one of the lysates tested. Together, these data indicate that the interaction between probiotics and paraprobiotics occurs in a strain dependent mechanism. Administration of probiotics and paraprobiotics as therapeutics therefore needs to be specific against the bacterial pathogen target

Patterns of Natural and Human-Caused Mortality Factors of a Rare Forest Carnivore, the Fisher (Pekania pennanti) in California.

Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti), a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%), natural disease (16%), toxicant poisoning (10%) and, less commonly, vehicular strike (2%) and other anthropogenic causes (2%) were causes of mortality observed. We documented both an increase in mortality to (57% increase) and exposure (6%) from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species

Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results

Enhanced vertical velocities associated with submesoscale motions may rapidly modify mixed layer depths and increase exchange between the mixed layer and the ocean interior. These dynamics are of particular importance in the Southern Ocean, where the ventilation of many density classes occurs. Here we present results from an observational field program in southern Drake Passage, a region preconditioned for submesoscale instability owing to its strong mesoscale eddy field, persistent fronts, strong down-front winds, and weak vertical stratification. Two gliders sampled from December 2014 through March 2015 upstream and downstream of the Shackleton Fracture Zone (SFZ). The acquired time series of mixed layer depths and buoyancy gradients enabled calculations of potential vorticity and classifications of submesoscale instabilities. The regions flanking the SFZ displayed remarkably different characteristics despite similar surface forcing. Mixed layer depths were nearly twice as deep, and horizontal buoyancy gradients were larger downstream of the SFZ. Upstream of the SFZ, submesoscale variability was confined to the edges of topographically steered fronts, whereas downstream these motions were more broadly distributed. Comparisons to a one-dimensional (1D) mixing model demonstrate the role of submesoscale instabilities in generating mixed layer variance. Numerical output from a submesoscale-resolving simulation indicates that submesoscale instabilities are crucial for correctly reproducing upper-ocean stratification. These results show that bathymetry can play a key role in generating dynamically distinct submesoscale characteristics over short spatial scales and that submesoscale motions can be locally active during summer months