3,079 research outputs found
Cost and Perceived Value in Obtaining a Bachelorâs Degree in Aviation Professional Flight: Will Collegiate Aviation Price Themselves Out of the Market with Technologically Advanced Aircraft?
Traditional academic baccalaureate degree programs have become increasingly expensive throughout the US. For collegiate aviation students, this news is even more daunting. Students obtaining a bachelor\u27s degree in aviation with a professional flight emphasis face unique challenges in today\u27s colleges and universities not typified by a majority of 4-year degree programs. Perhaps the most distinctive challenge lays in the financial arena of cost and return on investment for a bachelor\u27s degree in professional flight. This article will examine the various barriers associated with a typical bachelor\u27s degree aviation student majoring in professional flight
A procedure for developing an acceptance test for airborne bathymetric lidar data application to NOAA charts in shallow waters
National Oceanic and Atmospheric Administration (NOAA) hydrographic data is typically acquired using sonar systems, with a small percent acquired via airborne lidar bathymetry for nearâshore areas. This study investigated an integrated approach for meeting NOAAâs hydrographic survey requirements for nearâshore areas of NOAA charts, using the existing topographicâbathymetric lidar data from USACEâs National Coastal Mapping Program (NCMP). Because these existing NCMP bathymetric lidar datasets were not collected to NOAA hydrographic surveying standards, it is unclear if, and under what circumstances, they might aid in meeting certain hydrographic surveying requirements. The NCMPâs bathymetric lidar data are evaluated through a comparison to NOAAâs Office of Coast Survey hydrographic data derived from acoustic surveys. As a result, it is possible to assess if NCMPâs bathymetry can be used to fill in the data gap shoreward of the navigable area limit line (0 to 4 meters) and if there is potential for applying NCMPâs bathymetry lidar data to nearâshore areas deeper than 10 meters. Based on the study results, recommendations will be provided to NOAA for the site conditions where this data will provide the most benefit. Additionally, this analysis may allow the development of future operating procedures and workflows using other topographicâ bathymetric lidar datasets to help update nearâshore areas of the NOAA charts
Local brain connectivity and associations with gender and age
ABSTRACTRegional homogeneity measures synchrony of resting-state brain activity in neighboring voxels, or local connectivity. The effects of age and gender on local connectivity in healthy subjects are unknown. We performed regional homogeneity analyses on resting state BOLD time series data acquired from 58 normal, healthy participants, ranging in age from 11 to 35 (mean 18.1±5.0 years, 32 males). Regional homogeneity was found to be highest for gray matter, with brain regions within the default mode network having the highest local connectivity values. There was a general decrease in regional homogeneity with age with the greatest reduction seen in the anterior cingulate and temporal lobe. Greater female local connectivity in the right hippocampus and amygdala was also noted, regardless of age. These findings suggest that local connectivity at the millimeter scale decreases during development as longer connections are formed, and underscores the importance of examining gender differences in imaging studies of healthy and clinical populations
WU Polyomavirus in Patients Infected with HIV or Hepatitis C Virus, Connecticut, USA, 2007
WU polyomavirus (WUPyV) was detected in 10 (8.3%) of 121 HIV-positive plasma specimens, 0 (0%) of 120 HIV-negative serum specimens, and 2 (2.5%) of 79 hepatitis C virus (HCV)âpositive serum specimens. KI polyomavirus was not detected in HIV-positive plasma or HCV-positive serum specimens. HIV-infected persons may be susceptible to systemic WUPyV infection
CANDELS: The Contribution of the Observed Galaxy Population to Cosmic Reionization
We present measurements of the specific ultraviolet luminosity density from a
sample of 483 galaxies at 6<z<8. These galaxies were selected from new deep
near-infrared HST imaging from the CANDELS, HUDF09 and ERS programs. In
contrast to the majority of previous analyses, which assume that the
distribution of galaxy ultraviolet (UV) luminosities follows a Schechter
distribution, and that the distribution continues to luminosities far below our
observable limit, we investigate the contribution to reionization from galaxies
which we can observe, free from these assumptions. We find that the observable
population of galaxies can sustain a fully reionized IGM at z=6, if the average
ionizing photon escape fraction (f_esc) is ~30%. A number of previous studies
have measured UV luminosity densities at these redshifts that vary by 5X, with
many concluding that galaxies could not complete reionization by z=6 unless a
large population of galaxies fainter than the detection limit were invoked, or
extremely high values of f_esc were present. The observed UV luminosity density
from our observed galaxy samples at z=7-8 is not sufficient to maintain a fully
reionized IGM unless f_esc>50%. Combining our observations with constraints on
the emission rate of ionizing photons from Ly-alpha forest observations at z=6,
we can constrain f_esc<34% (2-sigma) if the observed galaxies are the only
contributors to reionization, or <13% (2-sigma) if the luminosity function
extends to M_UV = -13. These escape fractions are sufficient to complete
reionization by z=6. These constraints imply that the volume ionized fraction
of the IGM becomes less than unity at z>7, consistent with a number of
complementary reionization probes. If faint galaxies dominate reionization,
future JWST observations will probe deep enough to see them, providing an
indirect constraint on the ionizing photon escape fraction [abridged].Comment: 16 pages, 7 figures, Submitted to the Astrophysical Journa
A novel inhibitor of p75-neurotrophin receptor improves functional outcomes in two models of traumatic brain injury.
The p75 neurotrophin receptor is important in multiple physiological actions including neuronal survival and neurite outgrowth during development, and after central nervous system injury. We have discovered a novel piperazine-derived compound, EVT901, which interferes with p75 neurotrophin receptor oligomerization through direct interaction with the first cysteine-rich domain of the extracellular region. Using ligand binding assays with cysteine-rich domains-fused p75 neurotrophin receptor, we confirmed that EVT901 interferes with oligomerization of full-length p75 neurotrophin receptor in a dose-dependent manner. Here we report that EVT901 reduces binding of pro-nerve growth factor to p75 neurotrophin receptor, blocks pro-nerve growth factor induced apoptosis in cells expressing p75 neurotrophin receptor, and enhances neurite outgrowth in vitro Furthermore, we demonstrate that EVT901 abrogates p75 neurotrophin receptor signalling by other ligands, such as prion peptide and amyloid-ÎČ. To test the efficacy of EVT901 in vivo, we evaluated the outcome in two models of traumatic brain injury. We generated controlled cortical impacts in adult rats. Using unbiased stereological analysis, we found that EVT901 delivered intravenously daily for 1 week after injury, reduced lesion size, protected cortical neurons and oligodendrocytes, and had a positive effect on neurological function. After lateral fluid percussion injury in adult rats, oral treatment with EVT901 reduced neuronal death in the hippocampus and thalamus, reduced long-term cognitive deficits, and reduced the occurrence of post-traumatic seizure activity. Together, these studies provide a new reagent for altering p75 neurotrophin receptor actions after injury and suggest that EVT901 may be useful in treatment of central nervous system trauma and other neurological disorders where p75 neurotrophin receptor signalling is affected
- âŠ