7,458 research outputs found
Hamiltonian formalism and the Garrett-Munk spectrum of internal waves in the ocean
Wave turbulence formalism for long internal waves in a stratified fluid is
developed, based on a natural Hamiltonian description. A kinetic equation
appropriate for the description of spectral energy transfer is derived, and its
self-similar stationary solution corresponding to a direct cascade of energy
toward the short scales is found. This solution is very close to the high
wavenumber limit of the Garrett-Munk spectrum of long internal waves in the
ocean. In fact, a small modification of the Garrett-Munk formalism includes a
spectrum consistent with the one predicted by wave turbulence.Comment: 4 pages latex fil
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Year 1 report for ‘Conserving Texas Biodiversity: Status, Trends, and Conservation Planning for Fishes of Greatest Conservation Need’
State Wildlife Grant Program, grant TX T-106-1 (CFDA# 15.634), Contract No. 459125 UTA14-001402Substantive progress was made on all major Project Activities in this first year:
Activity 1. Coordinate and Facilitate Science and Conservation Actions for Conserving Texas Biodiversity - We expanded and strengthened UT-TPWD coordination, transitioning the relationship between these partners into a much more collaborative one than was previously realized. The flow of data between TPWD and the Fishes of Texas Project (supported in part by this project) has become much more bi-directional. Many newly collected TPWD specimens, agency databases, legacy data products and reports, and feedback from resource managers are now beginning to contribute substantively to growth and diversity (now including non-specimen-vouchered records) of data served through the FoTX Project’s websites. Work on cleaning and normalizing of FoTX’s online specimen-vouchered database continued, and the updated FoTX occurrence and distribution data are being actively used. Most recently they were used by this project, together with expert (TPWD, UT and others’) opinions, to develop recommendations on conservation status of native fishes of Texas’ Species of Greatest Conservation Need for TPWD’s consideration in anticipated updates to the Texas Conservation Action Plan. Within two months of this report, a new and substantially larger and improved version of the FoTX website/database and related collection of images, field notes, and ancillary datasets, will be formally announced.
Activity 2. Identify Priority Geographic Management Units for Conserving Fishes of Greatest Conservation Need - We used FoTX data in a systematic conservation area prioritization analysis to identify Native Fish Conservation Areas (NFCAs) for large portions of Texas where such comprehensive planning had not been previously carried out. Updated and new FoTX data for all Texas fish Species of Greatest Conservation Need (SGCN) were used in production of newly improved Species Distribution Models for input into this planning process, and the results of the planning exercise have already been integrated by TPWD into management prioritizations of both those species and the resultant NFCAs.
Activity 3. Develop Monitoring and Conservation Plans for Native Fish Conservation Areas - Monitoring and conservation plans were delivered to TPWD for all NFCAs identified in Activity 2.
Activity 4. Conduct Field-Based Surveys Detailed Biodiversity Assessments (i.e. Bioblitzing), and Citizen-Based Monitoring - Field surveys with detailed biodiversity assessments (“bioblitzes”) and citizen-based monitoring were conducted in three areas selected collaboratively by TPWD and FoTX Project staff from within the identified NFCAs: Nueces River headwaters, Big Cypress Bayou basin, and Village Creek basin. Along with this field effort, FoTX Project staff developed and circulated guidelines and best practices, and provided training for citizen-based monitoring that leverages iNaturalist for capture and reporting of photo-vouchered occurrence records in ways that will help assure scientifically useful data are obtained. All specimens acquired during these field efforts, and from many other routine specimen acquisitions from across the state (1845 total records/jars of specimens), were cataloged in the UT Fish Collection database. From there, these new records will soon be fed into GBIF, VertNet, FishNet2 and other major online data aggregators, including the online Fishes of Texas database.Texas Parks and Wildlife Department; U.S. Fish and Wildlife ServiceIntegrative Biolog
Previously Unidentified Changes in Renal Cell Carcinoma Gene Expression Identified by Parametric Analysis of Microarray Data
BACKGROUND. Renal cell carcinoma is a common malignancy that often presents as a metastatic-disease for which there are no effective treatments. To gain insights into the mechanism of renal cell carcinogenesis, a number of genome-wide expression profiling studies have been performed. Surprisingly, there is very poor agreement among these studies as to which genes are differentially regulated. To better understand this lack of agreement we profiled renal cell tumor gene expression using genome-wide microarrays (45,000 probe sets) and compare our analysis to previous microarray studies. METHODS. We hybridized total RNA isolated from renal cell tumors and adjacent normal tissue to Affymetrix U133A and U133B arrays. We removed samples with technical defects and removed probesets that failed to exhibit sequence-specific hybridization in any of the samples. We detected differential gene expression in the resulting dataset with parametric methods and identified keywords that are overrepresented in the differentially expressed genes with the Fisher-exact test. RESULTS. We identify 1,234 genes that are more than three-fold changed in renal tumors by t-test, 800 of which have not been previously reported to be altered in renal cell tumors. Of the only 37 genes that have been identified as being differentially expressed in three or more of five previous microarray studies of renal tumor gene expression, our analysis finds 33 of these genes (89%). A key to the sensitivity and power of our analysis is filtering out defective samples and genes that are not reliably detected. CONCLUSIONS. The widespread use of sample-wise voting schemes for detecting differential expression that do not control for false positives likely account for the poor overlap among previous studies. Among the many genes we identified using parametric methods that were not previously reported as being differentially expressed in renal cell tumors are several oncogenes and tumor suppressor genes that likely play important roles in renal cell carcinogenesis. This highlights the need for rigorous statistical approaches in microarray studies.National Institutes of Healt
Remarks on monopole charge properties within the Generalized Coherent State Model
The Generalized Coherent State Model, proposed previously for a unified
description of magnetic and electric collective properties of nuclear systems,
is used to study the ground state band charge density as well as the E0
transitions from to . The influence of the nuclear
deformation and of angular momentum projection on the charge density is
investigated. The monopole transition amplitude has been calculated for ten
nuclei. The results are compared with some previous theoretical studies and
with the available experimental data. Our results concerning angular momentum
projection are consistent with those of previous microscopic calculations for
the ground state density. The calculations for the E0 transitions agree quite
well with the experimental data. Issues like how the shape transitions or shape
coexistence are reflected in the behavior are also addressed.Comment: 32 pages, 7 figure
Walnut agroforestry (1996)
Agroforestry, or growing trees and other crops together on the same land, has been practiced for years in other countries to achieve more sustainable and productive use of limited land resources. In the U.S., forestry and agriculture historically have been considered mutually exclusive land use alternatives. But with clear management objectives, careful planning and skillful intensive management, combining crops and trees can provide advantages that outweigh any perceived disadvantages. Agroforestry is a potential alternative to conventional mechanical methods for soil erosion control. It also allows for gradual removal of highly erodible cropland from row-crop production.New 1/92, Reprinted 5/96/5
Kinematic Analysis of Obstacle Clearance During Locomotion
This study investigated the effect of obstacles of different heights on the locomotion of 15 healthy subjects. The following parameters were studied: (1) the distance of the toe and heel markers from the obstacle during toe-off and heel contact, respectively, (2) the minimum clearance distance of the toe and heel markers, and (3) the angular displacements and velocities of the hip, knee, and ankle. Results show significant differences in joint angular kinematics and clearance distances as obstacle height increased. The kinematic and distance differences exhibited both strong linear and non-linear trends. Toe-off distance and heel contact distance did not change significantly with changes in obstacle height
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