Winter-to-summer transition of Arctic sea ice breakup and floe size distribution in the Beaufort Sea

Breakup of the near-continuous winter sea ice into discrete summer ice floes is an important transition that dictates the evolution and fate of the marginal ice zone (MIZ) of the Arctic Ocean. During the winter of 2014, more than 50 autonomous drifting buoys were deployed in four separate clusters on the sea ice in the Beaufort Sea, as part of the Office of Naval Research MIZ program. These systems measured the ocean-ice-atmosphere properties at their location whilst the sea ice parameters in the surrounding area of these buoy clusters were continuously monitored by satellite TerraSAR-X Synthetic Aperture Radar. This approach provided a unique Lagrangian view of the winter-to-summer transition of sea ice breakup and floe size distribution at each cluster between March and August. The results show the critical timings of a) temporary breakup of winter sea ice coinciding with strong wind events and b) spring breakup (during surface melt, melt ponding and drainage) leading to distinctive summer ice floes. Importantly our results suggest that summer sea ice floe distribution is potentially affected by the state of winter sea ice, including the composition and fracturing (caused by deformation events) of winter sea ice, and that substantial mid-summer breakup of sea ice floes is likely linked to the timing of thermodynamic melt of sea ice in the area. As the rate of deformation and thermodynamic melt of sea ice has been increasing in the MIZ in the Beaufort Sea, our results suggest that these elevated factors would promote faster and more enhanced breakup of sea ice, leading to a higher melt rate of sea ice and thus a more rapid advance of the summer MIZ

Measuring Exercise Capacity and Physical Function in Adult and Older Mice

The inability of older adults to maintain independence is a consequence of sarcopenia and frailty. In order to identify the molecular mechanisms responsible for decreased physical function, it will be critical to utilize a small animal model. The main purpose of this study was to develop a composite Comprehensive Functional Assessment Battery (CFAB) of well-validated tests to determine physical function and exercise capacity in 3 age groups of male C57BL/6 mice (6 months old, n = 29; 24 months old, n = 24; 28+ months old, n = 28). To measure physical function in mice, we used rotarod (overall motor function), grip meter (forelimb strength), treadmill (endurance), inverted cling (strength/endurance), voluntary wheel running (volitional exercise and activity rate), and muscle performance with in vivo contractile physiology (dorsiflexor torque). We hypothesized that CFAB would be a valid means to assess the physical function of a given mouse across the life span. In addition, we proposed that CFAB could be used to determine relationships between different parameters associated with sarcopenia. We found that there was an overall age-related significant decline (p < .05) in all measurements, and the CFAB score demonstrated that some individual mice (the upper quartile) retained the functional capacity of average mice 1 cohort younger. We conclude that the CFAB is a powerful, repeatable, and noninvasive tool to assess and compare physical function and assess complex motor task ability in mice, which will enable researchers to easily track performance at the individual mouse level

Decreases in Antimicrobial Use Associated With Multihospital Implementation of Electronic Antimicrobial Stewardship Tools.

BackgroundAntimicrobial stewards may benefit from comparative data to inform interventions that promote optimal inpatient antimicrobial use.MethodsAntimicrobial stewards from 8 geographically dispersed Veterans Affairs (VA) inpatient facilities participated in the development of antimicrobial use visualization tools that allowed for comparison to facilities of similar complexity. The visualization tools consisted of an interactive web-based antimicrobial dashboard and, later, a standardized antimicrobial usage report updated at user-selected intervals. Stewards participated in monthly learning collaboratives. The percent change in average monthly antimicrobial use (all antimicrobial agents, anti-methicillin-resistant Staphylococcus aureus [anti-MRSA] agents, and antipseudomonal agents) was analyzed using a pre-post (January 2014-January 2016 vs July 2016-January 2018) design with segmented regression and external comparison with uninvolved control facilities (n = 118).ResultsIntervention sites demonstrated a 2.1% decrease (95% confidence interval [CI], -5.7% to 1.6%) in total antimicrobial use pre-post intervention vs a 2.5% increase (95% CI, 0.8% to 4.1%) in nonintervention sites (absolute difference, 4.6%; P = .025). Anti-MRSA antimicrobial use decreased 11.3% (95% CI, -16.0% to -6.3%) at intervention sites vs a 6.6% decrease (95% CI, -9.1% to -3.9%) at nonintervention sites (absolute difference, 4.7%; P = .092). Antipseudomonal antimicrobial use decreased 3.4% (95% CI, -8.2% to 1.7%) at intervention sites vs a 3.6% increase (95% CI, 0.8% to 6.5%) at nonintervention sites (absolute difference, 7.0%; P = .018).ConclusionsComparative data visualization tool use by stewards at 8 VA facilities was associated with significant reductions in overall antimicrobial and antipseudomonal use relative to uninvolved facilities

Intermediate Vancomycin Susceptibility in a Community-associated MRSA Clone

We describe a case of treatment failure caused by a strain of USA300 community-associated methicillin-resistant Staphylococcus aureus (MRSA) with intermediate susceptibility to vancomycin and reduced susceptibility to daptomycin. The strain was isolated from the bone of a 56-year-old man with lumbar osteomyelitis after a 6-week treatment course of vancomycin for catheter-associated septic thrombophlebitis

Index

Seafloor massive sulfide deposits form in remote environments, and the assessment of deposit size and composition through drilling is technically challenging and expensive. To aid the evaluation of the resource potential of seafloor massive sulfide deposits, three-dimensional inverse modelling of geophysical potential field data (magnetic and gravity) collected near the seafloor can be carried out to further enhance geologic models interpolated from sparse drilling. Here, we present inverse modelling results of magnetic and gravity data collected from the active mound at the Trans-Atlantic Geotraverse hydrothermal vent field, located at 26o08'N on the Mid-Atlantic Ridge, using autonomous underwater vehicle (AUV) and submersible surveying. Both minimum-structure and surface geometry inverse modelling methods were utilized. Through deposit-scale magnetic modelling, the outer extent of a chloritized alteration zone within the basalt host rock below the mound was resolved, providing an indication of the angle of the rising hydrothermal fluid and the depth and volume of seawater/hydrothermal mixing zone. The thickness of the massive sulfide mound was determined by modelling the gravity data, enabling the tonnage of the mound to be estimated at 2.17 +/- 0.44 Mt through this geophysics-based, non-invasive approach

Wettability decay in an oil-contaminated waste-mineral mixture with dry-wet cycles

The dependency of soil particle wettability on soil water content implies that soils subjected to drying-wetting cycles become wettable with wetting and water repellent with drying. While this has been demonstrated widely, the results are contradictory when water repellent soils are subjected to a sequence of cycles. Added to this, past wettability measurements were seldom done in batches of samples collected from the field at natural or dry water contents, with little appreciation that slight particle size variations, different drying-wetting histories and fabric (as required by different wettability measurement methods) may alter the results. This note presents soil particle wettability—soil water content relations by means of an index test following staged drying and wetting paths over a period of 8 months for an untreated, oil-contaminated anthropogenic soil (a mixture of slag, coal particles, fly ash and mineral particles) from Barry Docks (UK), a site formally used for oil storage, which is to be remediated and redeveloped for housing. The results revealed a decrease in the water repellency and increasing mineralization and bacterial activity with the wetting and drying cycles.postprin

Think twice: A cognitive perspective of an antibiotic timeout intervention to improve antibiotic use

ObjectivesTo understand clinicians' impressions of and decision-making processes regarding an informatics-supported antibiotic timeout program to re-evaluate the appropriateness of continuing vancomycin and piperacillin/tazobactam.MethodsWe implemented a multi-pronged informatics intervention, based on Dual Process Theory, to prompt discontinuation of unwarranted vancomycin and piperacillin/tazobactam on or after day three in a large Veterans Affairs Medical Center. Two workflow changes were introduced to facilitate cognitive deliberation about continuing antibiotics at day three: (1) teams completed an electronic template note, and (2) a paper summary of clinical and antibiotic-related information was provided to clinical teams. Shortly after starting the intervention, six focus groups were conducted with users or potential users. Interviews were recorded and transcribed. Iterative thematic analysis identified recurrent themes from feedback.ResultsThemes that emerged are represented by the following quotations: (1) captures and controls attention ("it reminds us to think about it"), (2) enhances informed and deliberative reasoning ("it makes you think twice"), (3) redirects decision direction ("…because [there was no indication] I just [discontinued] it without even trying"), (4) fosters autonomy and improves team empowerment ("the template… forces the team to really discuss it"), and (5) limits use of emotion-based heuristics ("my clinical concern is high enough I think they need more aggressive therapy…").ConclusionsRequiring template completion to continue antibiotics nudged clinicians to re-assess the appropriateness of specified antibiotics. Antibiotic timeouts can encourage deliberation on overprescribed antibiotics without substantially curtailing autonomy. An effective nudge should take into account clinician's time, workflow, and thought processes

Medical Intensive Care Unit Admission Among Patients With and Without HIV, Hepatitis C Virus, and Alcohol-Related Diagnoses in the United States: A National, Retrospective Cohort Study, 1997-2014.

BACKGROUND: HIV, hepatitis C virus (HCV), and alcohol-related diagnoses (ARD) independently contribute increased risk of all-cause hospitalization. We sought to determine annual medical intensive care unit (MICU) admission rates and relative risk of MICU admission between 1997 and 2014 among people with and without HIV, HCV, and ARD, using data from the largest HIV and HCV care provider in the United States. SETTING: Veterans Health Administration. METHODS: Annual MICU admission rates were calculated among 155,550 patients in the Veterans Aging Cohort Study by HIV, HCV, and ARD status. Adjusted rate ratios and 95% confidence intervals (CIs) were estimated with Poisson regression. Significance of trends in age-adjusted admission rates were tested with generalized linear regression. Models were stratified by calendar period to identify shifts in MICU admission risk over time. RESULTS: Compared to HIV-/HCV-/ARD- patients, relative risk of MICU admission decreased among HIV-mono-infected patients from 61% (95% CI: 1.56 to 1.65) in 1997-2009% to 21% (95% CI: 1.16 to 1.27) in 2010-2014, increased among HCV-mono-infected patients from 22% (95% CI: 1.16 to 1.29) in 1997-2009% to 54% (95% CI: 1.43 to 1.67) in 2010-2014, and remained consistent among patients with ARD only at 46% (95% CI: 1.42 to 1.50). MICU admission rates decreased by 48% among HCV-uninfected patients (P-trend <0.0001) but did not change among HCV+ patients (P-trend = 0.34). CONCLUSION: HCV infection and ARD remain key contributors to MICU admission risk. The impact of each of these conditions could be mitigated with combination of treatment of HIV, HCV, and interventions targeting unhealthy alcohol use

The Inner-Shelf Dynamics Experiment

17 USC 105 interim-entered record; under review.The article of record as published may be found at http://dx.doi.org/10.1175/BAMS-D-19-0281.1The inner shelf, the transition zone between the surfzone and the midshelf, is a dynamically complex region with the evolution of circulation and stratification driven by multiple physical processes. Cross-shelf exchange through the inner shelf has important implications for coastal water quality, ecological connectivity, and lateral movement of sediment and heat. The Inner-Shelf Dynamics Experiment (ISDE) was an intensive, coordinated, multi-institution field experiment from September–October 2017, conducted from the midshelf, through the inner shelf, and into the surfzone near Point Sal, California. Satellite, airborne, shore- and ship-based remote sensing, in-water moorings and ship-based sampling, and numerical ocean circulation models forced by winds, waves, and tides were used to investigate the dynamics governing the circulation and transport in the inner shelf and the role of coastline variability on regional circulation dynamics. Here, the following physical processes are highlighted: internal wave dynamics from the midshelf to the inner shelf; flow separation and eddy shedding off Point Sal; offshore ejection of surfzone waters from rip currents; and wind-driven subtidal circulation dynamics. The extensive dataset from ISDE allows for unprecedented investigations into the role of physical processes in creating spatial heterogeneity, and nonlinear interactions between various inner-shelf physical processes. Overall, the highly spatially and temporally resolved oceanographic measurements and numerical simulations of ISDE provide a central framework for studies exploring this complex and fascinating region of the ocean.U.S. Office of Naval Research (ONR)ONR Departmental Research Initiative (DRI)Inner-Shelf Dynamics Experiment (ISDE

Genetic Networks of Liver Metabolism Revealed by Integration of Metabolic and Transcriptional Profiling

Although numerous quantitative trait loci (QTL) influencing disease-related phenotypes have been detected through gene mapping and positional cloning, identification of the individual gene(s) and molecular pathways leading to those phenotypes is often elusive. One way to improve understanding of genetic architecture is to classify phenotypes in greater depth by including transcriptional and metabolic profiling. In the current study, we have generated and analyzed mRNA expression and metabolic profiles in liver samples obtained in an F2 intercross between the diabetes-resistant C57BL/6 leptinob/ob and the diabetes-susceptible BTBR leptinob/ob mouse strains. This cross, which segregates for genotype and physiological traits, was previously used to identify several diabetes-related QTL. Our current investigation includes microarray analysis of over 40,000 probe sets, plus quantitative mass spectrometry-based measurements of sixty-seven intermediary metabolites in three different classes (amino acids, organic acids, and acyl-carnitines). We show that liver metabolites map to distinct genetic regions, thereby indicating that tissue metabolites are heritable. We also demonstrate that genomic analysis can be integrated with liver mRNA expression and metabolite profiling data to construct causal networks for control of specific metabolic processes in liver. As a proof of principle of the practical significance of this integrative approach, we illustrate the construction of a specific causal network that links gene expression and metabolic changes in the context of glutamate metabolism, and demonstrate its validity by showing that genes in the network respond to changes in glutamine and glutamate availability. Thus, the methods described here have the potential to reveal regulatory networks that contribute to chronic, complex, and highly prevalent diseases and conditions such as obesity and diabetes