310 research outputs found
A Comparison of Drill and Broadcast Planting Methods forBiomass Production of Two Legume Cover Crops
The effects of drill and broadcast planting methods on cover crop biomass production depend on various environmental and operational factors. We investigated whether drilling and broadcasting result in different amounts of biomass production by crimson clover (Trifolium incarnatum L.) and hairy vetch (Vicia villosa Roth) in the upstate of South Carolina, and results vary when seeding rates are increased by 50% from the standard value (22.4 kg ha−1). Field trials were conducted during the fall–winter of 2019–2020 (season one) and 2020–2021 (season two) at the Piedmont Research and Education Center in Pendleton, SC, USA. Cover crop (hairy vetch, crimson clover), planting method (broadcast, drill), and seeding rate (standard, high) treatments were arranged as a 2 × 2 × 2 factorial in both years. Aboveground biomass was measured after 22.5 weeks from planting. At standard seeding rates, crimson clover produced a higher biomass when drilled, rather than broadcasted, whereas biomass production did not vary for hairy vetch. Even with 50% higher seeding rates, broadcasting did not always produce the same biomass as that of drilling for crimson clover. Our results suggest that the advantage of drilling over broadcasting depends upon the cover crop species, as crimson clover responds well to drilling, whereas hairy vetch does not
Transmyocardial laser revascularization fails to prevent left ventricular functional deterioration and aneurysm formation after acute myocardial infarction in sheep
AbstractObjective: Transmyocardial laser revascularization is an investigational technique for revascularizing ischemic myocardium in patients with inoperable coronary arterial disease. This study tests the hypothesis that laser revascularization prevents left ventricular functional deterioration and aneurysm formation after acute anteroapical myocardial infarction. Methods: An ultrasonic ascending aortic flow probe and snares around the distal left anterior descending and second diagonal coronary arteries were placed in 26 Dorsett hybrid sheep. Ten to 14 days later, snared arteries were occluded to produce an anteroapical infarction of 23% of left ventricular mass. Before infarction 14 animals had 34 ± 4 transmyocardial perforations in the area of the anticipated infarction made with a carbon dioxide laser. Twelve animals served as controls. Hemodynamic measurements and transdiaphragmatic quantitative echocardiograms were obtained before, immediately after, and 2, 5, and 8 weeks after infarction. Eighteen sheep completed the protocol. Results: All animals had large anteroapical left ventricular aneurysms with massive ventricular enlargement. Immediately after infarction the anterior wall became thinner and dyskinetic in all sheep. At 8 weeks aneurysmal size and shape were indistinguishable between groups. Two days after infarction, laser holes were filled with fibrin. At 5 and 8 weeks the infarct consisted of dense collagen, fibroblasts, scattered calcifications, myocyte fragments, neutrophils, macrophages, and no laser holes. There were no significant differences at any time between groups for cardiac pressures or output, ventricular volumes, ejection fraction, stroke work, and the stroke work–left ventricular end-diastolic pressure index. Conclusion: Transmyocardial laser perforations do not revascularize acute myocardial infarction in sheep. (J Thorac Cardiovasc Surg 1998;116:752-62
Lunar Volatile and Mineralogy Mapping Orbiter (VMMO): Viable Science from Lunar CubeSats
The Volatile and Mineralogy Mapping Orbiter (VMMO) is a low-cost 12U CubeSat concept that was originally selected by the European Space Agency (ESA) as one of the two winners of the 2018 SysNova Challenge. The VMMO spacecraft will carry out a volatiles and mineralogical survey of the lunar South Pole permanently shadowed regions using the Lunar Volatile and Mineralogy Mapper (LVMM) multi-wave chemical Lidar payload to detect and map volatiles and other resources such as ilmenite (FeTiO3) down to a Ground Sample Distance (GSD) of approximately 100m. The exploitation of valuable lunar resources, such as water ice and other volatiles, will be crucial to the sustainability of future manned lunar bases. Although water ice has already been detected and mapped around the poles of the Moon by previous lunar missions, there is still considerable uncertainty with regards to the precise distribution of volatile content within the lunar regolith. There are a number of planned future missions to further locate and map water ice deposits around the lunar poles, but the spatial resolution of these observations is still expected to be on the order of kilometres.
This paper will describe the VMMO mission and CubeSat spacecraft design work that was carried out in the recent Phase A study for ESA. It also aims to address some of the key objectives and challenges involved in designing a low-cost, semi-autonomous CubeSat for beyond-Earth orbit
Normally preordered spaces and utilities
In applications it is useful to know whether a topological preordered space
is normally preordered. It is proved that every -space equipped with
a closed preorder is a normally preordered space. Furthermore, it is proved
that second countable regularly preordered spaces are perfectly normally
preordered and admit a countable utility representation.Comment: 17 pages, 1 figure. v2 contains a second proof to the main theorem
with respect to the published version. The last section of v1 is not present
in v2. It will be included in a different wor
Stochastic Processes Are Key Determinants of Short-Term Evolution in Influenza A Virus
Understanding the evolutionary dynamics of influenza A virus is central to its surveillance and control. While immune-driven antigenic drift is a key determinant of viral evolution across epidemic seasons, the evolutionary processes shaping influenza virus diversity within seasons are less clear. Here we show with a phylogenetic analysis of 413 complete genomes of human H3N2 influenza A viruses collected between 1997 and 2005 from New York State, United States, that genetic diversity is both abundant and largely generated through the seasonal importation of multiple divergent clades of the same subtype. These clades cocirculated within New York State, allowing frequent reassortment and generating genome-wide diversity. However, relatively low levels of positive selection and genetic diversity were observed at amino acid sites considered important in antigenic drift. These results indicate that adaptive evolution occurs only sporadically in influenza A virus; rather, the stochastic processes of viral migration and clade reassortment play a vital role in shaping short-term evolutionary dynamics. Thus, predicting future patterns of influenza virus evolution for vaccine strain selection is inherently complex and requires intensive surveillance, whole-genome sequencing, and phenotypic analysis
Functional assessment of older patients in the emergency department: comparison between standard instruments, medical records and physicians' perceptions
BACKGROUND: We evaluated the accuracy of physician recognition of functional status impairment in older emergency departments (ED) patients. In particular, we evaluated the accuracy of medical records (a comparison of the information in the medical record with the functional status based on proxy interviews), and the accuracy of physician knowledge (a comparison of the information obtained from the responsible physician with the functional status based on proxy interviews). METHODS: Cross-sectional study on 101 frail older patients selected at random from among those attending ED, their ED physicians, and respondents. The study was conducted at ED in four general university teaching hospitals in a city, from July through November 2003. Functional data shown on patients' medical records were compared against functional data obtained from respondents (family members), using Kendall's Tau-b statistic. In addition patients' Katz Indices (which assesses six basic activities of daily living – basic ADL) based on interviews with ED physicians were compared against those obtained from respondents, using the coefficient of concordance weighted kappa (κ). Each patient and his respondent were paired with a single physician. RESULTS: The correlation between information on dependence for basic ADL obtained from medical records and that furnished by respondents, was 0.41 (95% CI 0.27–0.55). Concordance between the respective Katz Indices obtained from physicians and respondents was 0.47 (95% CI 0.38–0.57). CONCLUSION: Older subjects' functional status is not properly assessed by emergency department physicians
A core human primary tumor angiogenesis signature identifies the endothelial orphan receptor ELTD1 as a key regulator of angiogenesis.
Limited clinical benefits derived from anti-VEGF therapy have driven the identification of new targets involved in tumor angiogenesis. Here, we report an integrative meta-analysis to define the transcriptional program underlying angiogenesis in human cancer. This approach identified ELTD1, an orphan G-protein-coupled receptor whose expression is induced by VEGF/bFGF and repressed by DLL4 signaling. Extensive analysis of multiple cancer types demonstrates significant upregulation of ELTD1 in tumor-associated endothelial cells, with a higher expression correlating with favorable prognosis. Importantly, ELTD1 silencing impairs endothelial sprouting and vessel formation in vitro and in vivo, drastically reducing tumor growth and greatly improving survival. Collectively, these results provide insight into the regulation of tumor angiogenesis and highlight ELTD1 as key player in blood vessel formation
School engagement among LGBTQ high school students: The roles of safe adults and gay–straight alliance characteristics
Drosophila Dynein Intermediate Chain Gene, Dic61B, Is Required for Spermatogenesis
This study reports the identification and characterization of a novel gene, Dic61B, required for male fertility in Drosophila. Complementation mapping of a novel male sterile mutation, ms21, isolated in our lab revealed it to be allelic to CG7051 at 61B1 cytogenetic region, since two piggyBac insertion alleles, CG7051c05439 and CG7051f07138 failed to complement. CG7051 putatively encodes a Dynein intermediate chain. All three mutants, ms21, CG7051c05439 and CG7051f07138, exhibited absolute recessive male sterility with abnormally coiled sperm axonemes causing faulty sperm individualization as revealed by Phalloidin staining in Don Juan-GFP background. Sequencing of PCR amplicons uncovered two point mutations in ms21 allele and confirmed the piggyBac insertions in CG7051c05439 and CG7051f07138 alleles to be in 5′UTR and 4th exon of CG7051 respectively, excision of which reverted the male sterility. In situ hybridization to polytene chromosomes demonstrated CG7051 to be a single copy gene. RT-PCR of testis RNA revealed defective splicing of the CG7051 transcripts in mutants. Interestingly, expression of cytoplasmic dynein intermediate chain, α, β, γ tubulins and α-spectrin was normal in mutants while ultra structural studies revealed defects in the assembly of sperm axonemes. Bioinformatics further highlighted the homology of CG7051 to axonemal dynein intermediate chain of various organisms, including DNAI1 of humans, mutations in which lead to male sterility due to immotile sperms. Based on these observations we conclude that CG7051 encodes a novel axonemal dynein intermediate chain essential for male fertility in Drosophila and rename it as Dic61B. This is the first axonemal Dic gene of Drosophila to be characterized at molecular level and shown to be required for spermatogenesis
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