1,524 research outputs found
Targeted ocean sampling guidance for tropical cyclones
This paper is not subject to U.S. copyright. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 3505–3518, doi:10.1002/2017JC012727.A 3-D variational ocean data assimilation adjoint approach is used to examine the impact of ocean observations on coupled tropical cyclone (TC) model forecast error for three recent hurricanes: Isaac (2012), Hilda (2015), and Matthew (2016). In addition, this methodology is applied to develop an innovative ocean observation targeting tool validated using TC model simulations that assimilate ocean temperature observed by Airborne eXpendable Bathy Thermographs and Air-Launched Autonomous Micro-Observer floats. Comparison between the simulated targeted and real observation data assimilation impacts reveals a positive maximum mean linear correlation of 0.53 at 400–500 m, which implies some skill in the targeting application. Targeted ocean observation regions from these three hurricanes, however, show that the largest positive impacts in reducing the TC model forecast errors are sensitive to the initial prestorm ocean conditions such as the location and magnitude of preexisting ocean eddies, storm-induced ocean cold wake, and model track errors.ONR Grant Numbers: N0001416WX01949, N0001416WX01384, N0001416WX01262;
NOAA Grant Number: NA13OAR483023
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Effect of Combination Folic Acid, Vitamin B6 , and Vitamin B12 Supplementation on Fracture Risk in Women: A Randomized, Controlled Trial.
Epidemiologic studies have demonstrated an association of elevated plasma homocysteine levels with greater bone resorption and fracture risk. Vitamins B12 , B6 , and folic acid are cofactors in homocysteine metabolism, and supplementation with B vitamins is effective in lowering homocysteine levels in humans. However, randomized trials of supplemental B vitamins for reduction of fracture risk have been limited. Therefore, we performed an ancillary study to the Women's Antioxidant and Folic Acid Cardiovascular Study (WAFACS), a large randomized trial of women with preexisting cardiovascular disease or three or more coronary risk factors, to test whether a daily B vitamin intervention including folic acid (2.5 mg/day), vitamin B6 (50 mg/day), and vitamin B12 (1 mg/day) reduces nonspine fracture risk over 7.3 years of treatment and follow-up. Among 4810 women, we confirmed 349 nonspine fracture cases by centralized review of medical records. In a substudy of 300 women (150 in treatment group and 150 controls) with paired plasma samples at randomization and follow-up (7.3 years later), we measured two bone turnover markers, including C-terminal cross-linking telopeptide of type I collagen (CTX) and intact type I procollagen N-propeptide (P1NP). In Cox proportional hazards models based on intention-to-treat, we found no significant effects of B vitamin supplementation on nonspine fracture risk (relative hazard = 1.08; 95% confidence interval, 0.88 to 1.34). In a nested case-cohort analysis, there were no significant effects of B vitamins on fracture risk among women with elevated plasma homocysteine levels, or low levels of vitamins B12 or B6 , or folate at baseline. Furthermore, treatment with B vitamins had no effect on change in markers of bone turnover. We found no evidence that daily supplementation with B vitamins reduces fracture risk or rates of bone metabolism in middle-aged and older women at high risk of cardiovascular disease. © 2017 American Society for Bone and Mineral Research
The complete plasmid sequences of Salmonella enterica serovar Typhimurium U288.
Salmonella enterica Serovar Typhimurium U288 is an emerging pathogen of pigs. The strain contains three plasmids of diverse origin that encode traits that are of concern for food security and safety, these include antibiotic resistant determinants, an array of functions that can modify cell physiology and permit genetic mobility. At 148,711 bp, pSTU288-1 appears to be a hybrid plasmid containing a conglomerate of genes found in pSLT of S. Typhimurium LT2, coupled with a mosaic of horizontally-acquired elements. Class I integron containing gene cassettes conferring resistance against clinically important antibiotics and compounds are present in pSTU288-1. A curious feature of the plasmid involves the deletion of two genes encoded in the Salmonella plasmid virulence operon (spvR and spvA) following the insertion of a tnpA IS26-like element coupled to a blaTEM gene. The spv operon is considered to be a major plasmid-encoded Salmonella virulence factor that is essential for the intracellular lifecycle. The loss of the positive regulator SpvR may impact on the pathogenesis of S. Typhimurium U288. A second 11,067 bp plasmid designated pSTU288-2 contains further antibiotic resistance determinants, as well as replication and mobilization genes. Finally, a small 4675 bp plasmid pSTU288-3 was identified containing mobilization genes and a pleD-like G-G-D/E-E-F conserved domain protein that modulate intracellular levels of cyclic di-GMP, and are associated with motile to sessile transitions in growth
Sustaining Educational Reforms in Introductory Physics
While it is well known which curricular practices can improve student
performance on measures of conceptual understanding, the sustaining of these
practices and the role of faculty members in implementing these practices are
less well understood. We present a study of the hand-off of Tutorials in
Introductory Physics from initial adopters to other instructors at the
University of Colorado, including traditional faculty not involved in physics
education research. The study examines the impact of implementation of
Tutorials on student conceptual learning across eight first-semester, and seven
second-semester courses, for fifteen faculty over twelve semesters, and
includes roughly 4000 students. It is possible to demonstrate consistently
high, and statistically indistinguishable, student learning gains for different
faculty members; however, such results are not the norm, and appear to rely on
a variety of factors. Student performance varies by faculty background -
faculty involved in, or informed by physics education research, consistently
post higher student learning gains than less-informed faculty. Student
performance in these courses also varies by curricula used - all semesters in
which the research-based Tutorials and Learning Assistants are used have higher
student learning gains than those semesters that rely on non-research based
materials and do not employ Learning Assistants.Comment: 21 pages, 4 figures, and other essential inf
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Individual and joint trajectories of change in bone, lean mass and physical performance in older men.
BackgroundDeclines in bone, muscle and physical performance are associated with adverse health outcomes in older adults. However, few studies have described concurrent age-related patterns of change in these factors. The purpose of this study was to characterize change in four properties of muscle, physical performance, and bone in a prospective cohort study of older men.MethodsUsing repeated longitudinal data from up to four visits across 6.9 years from up to 4681 men (mean age at baseline 72.7 yrs. ±5.3) participating in the Osteoporotic Fractures in Men (MrOS) Study, we used group-based trajectory models (PROC TRAJ in SAS) to identify age-related patterns of change in four properties of muscle, physical performance, and bone: total hip bone mineral (BMD) density (g/m2) and appendicular lean mass/ht2 (kg/m2), by DXA; grip strength (kg), by hand dynamometry; and walking speed (m/s), by usual walking pace over 6 m. We also described joint trajectories in all pair-wise combinations of these measures. Mean posterior probabilities of placement in each trajectory (or joint membership in latent groups) were used to assess internal reliability of the model. The number of trajectories for each individual factor was limited to three, to ensure that the pair-wise determination of joint trajectories would yield a tractable number of groups as well as model fit considerations.ResultsThe patterns of change identified were generally similar for all measures, with three district groups declining over time at roughly similar rates; joint trajectories revealed similar patterns with no cross-over or convergence between groups. Mean posterior probabilities for all trajectories were similar and consistently above 0.8 indicating reasonable model fit to the data.ConclusionsOur description of trajectories of change with age in bone mineral density, grip strength, walking speed and appendicular lean mass found that groups identified by these methods appeared to have little crossover or convergence of change with age, even when considering joint trajectories of change in these factors
Implicit sequence learning in people with Parkinson\u27s disease
Implicit sequence learning involves learning about dependencies in sequences of events without intent to learn or awareness of what has been learned. Sequence learning is related to striatal dopamine levels, striatal activation, and integrity of white matter connections. People with Parkinson’s disease (PD) have degeneration of dopamine-producing neurons, leading to dopamine deficiency and therefore striatal deficits, and they have difficulties with sequencing, including complex language comprehension and postural stability. Most research on implicit sequence learning in PD has used motor-based tasks. However, because PD presents with motor deficits, it is difficult to assess whether learning itself is impaired in these tasks. The present study used an implicit sequence learning task with a reduced motor component, the Triplets Learning Task (TLT). People with PD and age- and education-matched healthy older adults completed three sessions (each consisting of 10 blocks of 50 trials) of the TLT. Results revealed that the PD group was able to learn the sequence, however, when learning was examined using a Half Blocks analysis (Nemeth et al., 2013), which compared learning in the 1st 25/50 trials of all blocks to that in the 2nd 25/50 trials, the PD group showed significantly less learning than Controls in the 2nd Half Blocks, but not in the 1st. Nemeth et al. (2013) hypothesized that the 1st Half Blocks involve recall and reactivation of the sequence learned, thus reflecting hippocampal-dependent learning, while the 2nd Half Blocks involve proceduralized behavior of learned sequences, reflecting striatal-based learning. The present results suggest that the PD group had intact hippocampal-dependent implicit sequence learning, but impaired striatal-dependent learning. Thus, sequencing deficits in PD are likely due to striatal impairments, but other brain systems, such as the hippocampus, may be able to partially compensate for striatal decline to improve performance
Raloxifene, a selective estrogen receptor modulator, is renoprotective: a post-hoc analysis
Estrogens have a protective effect on kidney fibrosis in several animal models. Here, we tested the effect of raloxifene, an estrogen receptor modulator, on the change in serum creatinine or estimated glomerular filtration rate (eGFR) and incident kidney-related adverse events. We performed a post-hoc analysis of the multiple outcomes of raloxifene evaluation trial, a double-masked, placebo-controlled randomized clinical trial encompassing 7705 post-menopausal women (aged 31–80 years) with osteoporosis. Participants were randomized to either of two doses of raloxifene, 60 or 120 mg/day, or placebo. Serum creatinine was measured at a central laboratory at baseline and annually. Adverse events were assessed every 6 months and uniformly categorized. Compared with those in the placebo group, participants on raloxifene had a slower yearly rate of increase in creatinine (significant at the low dose) and a significantly slower yearly rate of decrease in eGFR for both doses over 3 years of follow-up. Raloxifene was associated with significantly fewer kidney-related adverse events compared with placebo. Thus, treatment with raloxifene was safe and renoprotective. Clinical trials of raloxifene in post-menopausal women with kidney disease designed to look at kidney outcomes are needed to confirm these findings
denosumab in postmenopausal women with osteoporosis and diabetes subgroup analysis of freedom and freedom extension
Abstract Purpose Diabetes and osteoporosis occur frequently in older adults and are both associated with increased fracture risk. Denosumab treatment reduced new vertebral, nonvertebral, and hip fractures over 3 years, with continued low fracture incidence for up to 10 years in postmenopausal women with osteoporosis. However, its effects in diabetic subjects with osteoporosis have not yet been investigated. Methods Post hoc analysis of the 3-year, placebo-controlled FREEDOM study and 7-year Extension included postmenopausal women with osteoporosis and diabetes. Effects on BMD, vertebral, and nonvertebral fracture incidence were evaluated. Results Of 7808 subjects in FREEDOM, 508 with diabetes received denosumab (n = 266) or placebo (n = 242). Among those, BMD increased significantly with denosumab versus placebo in FREEDOM, and continued to increase during the Extension in long-term (continuing denosumab) and crossover (placebo to denosumab) denosumab subjects. In FREEDOM, denosumab-treated subjects with diabetes had significantly lower new vertebral fracture rates (1.6%) versus placebo (8.0%) (RR: 0.20 [95% CI 0.07–0.61]; p = .001). Nonvertebral fracture incidence was higher with denosumab (11.7%) versus placebo (5.9%) (HR: 1.94 [95% CI 1.00–3.77]; p = .046), although there were fewer hip fractures with denosumab (World Health Organization, 2017 [ 1 ]) than placebo (4; nonsignificant). During the first 3 years in FREEDOM Extension, new vertebral and nonvertebral fracture incidences were low in long-term and crossover denosumab diabetic groups (≤6%), consistent with the overall Extension population; yearly nonvertebral fracture incidence was comparable to the FREEDOM placebo group. Conclusion Denosumab significantly increased BMD and decreased vertebral fracture risk in subjects with osteoporosis and diabetes. No reduction in nonvertebral fractures was observed
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