614 research outputs found
Bat Quickness and Bat Velocity for Left- and Right-Handed Softball Swings
Please view abstract in the attached PDF fil
Genomic abundance is not predictive of tandem repeat localization in grass genomes.
Highly repetitive regions have historically posed a challenge when investigating sequence variation and content. High-throughput sequencing has enabled researchers to use whole-genome shotgun sequencing to estimate the abundance of repetitive sequence, and these methodologies have been recently applied to centromeres. Previous research has investigated variation in centromere repeats across eukaryotes, positing that the highest abundance tandem repeat in a genome is often the centromeric repeat. To test this assumption, we used shotgun sequencing and a bioinformatic pipeline to identify common tandem repeats across a number of grass species. We find that de novo assembly and subsequent abundance ranking of repeats can successfully identify tandem repeats with homology to known tandem repeats. Fluorescent in-situ hybridization shows that de novo assembly and ranking of repeats from non-model taxa identifies chromosome domains rich in tandem repeats both near pericentromeres and elsewhere in the genome
Short-Term Calorie Restriction in Male Mice Feminizes Gene Expression and Alters Key Regulators of Conserved Aging Regulatory Pathways
Background: Calorie restriction (CR) is the only intervention known to extend lifespan in a wide range of organisms, including mammals. However, the mechanisms by which it regulates mammalian aging remain largely unknown, and the involvement of the TOR and sirtuin pathways (which regulate aging in simpler organisms) remain controversial. Additionally, females of most mammals appear to live longer than males within species; and, although it remains unclear whether this holds true for mice, the relationship between sex-biased and CR-induced gene expression remains largely unexplored. Methodology/Principal Findings: We generated microarray gene expression data from livers of male mice fed high calorie or CR diets, and we find that CR significantly changes the expression of over 3,000 genes, many between 10- and 50-fold. We compare our data to the GenAge database of known aging-related genes and to prior microarray expression data of genes expressed differently between male and female mice. CR generally feminizes gene expression and many of the most significantly changed individual genes are involved in aging, hormone signaling, and p53-associated regulation of the cell cycle and apoptosis. Among the genes showing the largest and most statistically significant CR-induced expression differences are Ddit4, a key regulator of the TOR pathway, and Nnmt, a regulator of lifespan linked to the sirtuin pathway. Using western analysis we confirmed post-translational inhibition of the TOR pathway. Conclusions: Our data show that CR induces widespread gene expression changes and acts through highly evolutionarily conserved pathways, from microorganisms to mammals, and that its life-extension effects might arise partly from a shift toward a gene expression profile more typical of females
Measuring subaqueous progradation of the Wax Lake Delta with a model of flow direction divergence
Remotely sensed flow patterns can reveal the location of
the subaqueous distal tip of a distributary channel on a prograding river
delta. Morphodynamic feedbacks produce distributary channels that become
shallower over their final reaches before the unchannelized foreset slopes
basinward. The flow direction field over this morphology tends to diverge
and then converge, providing a diagnostic signature that can be captured in
flow or remote sensing data. A total of 21 measurements from the Wax Lake Delta
(WLD) in coastal Louisiana and 317 measurements from numerically simulated
deltas show that the transition from divergence to convergence occurs in a
distribution that is centered just downstream of the channel tip, on average
132 m in the case of the WLD. These data validate an inverse model for
remotely estimating subaqueous channel tip location. We apply this model to
33 images of the WLD between its initiation in 1974 and 2016. We find that
six
of the primary channels grew at rates of 60–80 m yr−1, while the remaining
channel grew at 116 m yr−1. We also show that the subaqueous delta planform
grew at a constant rate (1.72 km2 yr−1). Subaerial land area initially
grew at the same rate but slowed after about 1999. We explain this behavior
as a gradual decoupling of channel tip progradation and island aggradation
that may be common in maturing deltas.</p
Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Ambulatory Heart Failure Patients The ROADMAP Study 2-Year Results
OBJECTIVES The authors sought to provide the pre-specified primary endpoint of the ROADMAP (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Ambulatory Heart Failure Patients) trial at 2 years. BACKGROUND The ROADMAP trial was a prospective nonrandomized observational study of 200 patients (97 with a left ventricular assist device [LVAD], 103 on optimal medical management [OMM]) that showed that survival with improved functional status at 1 year was better with LVADs compared with OMM in a patient population of ambulatory New York Heart Association functional class IIIb/IV patients. METHODS The primary composite endpoint was survival on original therapy with improvement in 6-min walk distance \u3e= 75 m. RESULTS Patients receiving LVAD versus OMM had lower baseline health-related quality of life, reduced Seattle Heart Failure Model 1-year survival (78% vs. 84%; p = 0.012), and were predominantly INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) profile 4 (65% vs. 34%; p \u3c 0.001) versus profiles 5 to 7. More LVAD patients met the primary endpoint at 2 years: 30% LVAD versus 12% OMM (odds ratio: 3.2 [95% confidence interval: 1.3 to 7.7]; p = 0.012). Survival as treated on original therapy at 2 years was greater for LVAD versus OMM (70 +/- 5% vs. 41 +/- 5%; p \u3c 0.001), but there was no difference in intent-to-treat survival (70 +/- 5% vs. 63 +/- 5%; p = 0.307). In the OMM arm, 23 of 103 (22%) received delayed LVADs (18 within 12 months; 5 from 12 to 24 months). LVAD adverse events declined after year 1 for bleeding (primarily gastrointestinal) and arrhythmias. CONCLUSIONS Survival on original therapy with improvement in 6-min walk distance was superior with LVAD compared with OMM at 2 years. Reduction in key adverse events beyond 1 year was observed in the LVAD group. The ROADMAP trial provides risk-benefit information to guide patient- and physician-shared decision making for elective LVAD therapy as a treatment for heart failure. (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Ambulatory Heart Failure Patients [ROADMAP]; NCT01452802
Ecological assessment of the marine ecosystems of Barbuda, West Indies: Using rapid scientific assessment to inform ocean zoning and fisheries management
A Youth-Leader Program in Baltimore City Recreation Centers: Lessons Learned and Applications
Peer-led interventions may be an effective means of addressing the childhood obesity epidemichowever, few studies have looked at the long-term sustainability of such programs. As part of a multilevel obesity prevention intervention, B'More Healthy Communities for Kids, 16 Baltimore college students were trained as youth-leaders (YLs) to deliver a skill-based nutrition curriculum to low-income African American children (10-14 years old). In April 2015, formative research was used to inform sustainability of the YL program in recreation centers. In-depth interviews were conducted with recreation center directors (n = 4) and the YLs (n = 16). Two focus groups were conducted with YLs (n = 7) and community youth-advocates (n = 10). Barriers to this program included difficulties with transportation, time constraints, and recruiting youth. Lessons learned indicated that improving trainings and incentives to youth were identified as essential strategies to foster continuity of the youth-led program and capacity building. High school students living close to the centers were identified as potential candidates to lead the program. Based on our findings, the initial intervention will be expanded into a sustainable model for implementation, using a train-the-trainer approach to empower community youth to be change agents of the food environment and role models.Johns Hopkins Urban Health InstituteGlobal Obesity Prevention Center at Johns HopkinsEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentOffice of the Director, National Institutes of Health [U54HD070725]646 CNPq [GDE: 249316/2013-7]Johns Hopkins Bloomberg Sch Publ Hlth, Baltimore, MD USAUniv Tennessee, Knoxville, TN USAUniv Fed Sao Paulo, Santos, SP, BrazilDept Recreat & Pk City Baltimore, Baltimore, MD USAUniv Maryland Extens, Ellicott City, MD USAUniv Fed Sao Paulo, Santos, SP, BrazilWeb of Scienc
Static non-reciprocity in mechanical metamaterials
Reciprocity is a fundamental principle governing various physical systems,
which ensures that the transfer function between any two points in space is
identical, regardless of geometrical or material asymmetries. Breaking this
transmission symmetry offers enhanced control over signal transport, isolation
and source protection. So far, devices that break reciprocity have been mostly
considered in dynamic systems, for electromagnetic, acoustic and mechanical
wave propagation associated with spatio-temporal variations. Here we show that
it is possible to strongly break reciprocity in static systems, realizing
mechanical metamaterials that, by combining large nonlinearities with suitable
geometrical asymmetries, and possibly topological features, exhibit vastly
different output displacements under excitation from different sides, as well
as one-way displacement amplification. In addition to extending non-reciprocity
and isolation to statics, our work sheds new light on the understanding of
energy propagation in non-linear materials with asymmetric crystalline
structures and topological properties, opening avenues for energy absorption,
conversion and harvesting, soft robotics, prosthetics and optomechanics.Comment: 19 pages, 3 figures, Supplementary information (11 pages and 5
figures
Framework for Leadership and Training of Biosafety Level 4 Laboratory Workers
One-sentence summary for table of contents: Training should include theoretical consideration of biocontainment principles, practical hands-on training, and mentored on-the-job experience
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