9,481 research outputs found

    Neutrino degeneracy and cosmological nucleosynthesis, revisited

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    A reexamination of the effects of non-zero degeneracies on Big Bang Nucleosynthesis is made. As previously noted, non-trivial alterations of the standard model conclusions can be induced only if excess lepton numbers L sub i, comparable to photon number densities eta sub tau, are assumed (where eta sub tau is approx. 3 times 10(exp 9) eta sub b). Furthermore, the required lepton number densities (L sub i eta sub tau) must be different for upsilon sub e than for upsilon sub mu and epsilon sub tau. It is shown that this loophole in the standard model of nucleosynthesis is robust and will not vanish as abundance and reaction rate determinations improve. However, it is also argued that theoretically (L sub e) approx. (L sub mu) approx. (L sub tau) approx. eta sub b is much less than eta sub tau which would preclude this loophole in standard unified models

    Benthic Habitat Characterization for the South Florida Ocean Measurement Facility (SFOMF)

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    This report summarizes the distribution and relative abundance of two stony coral species (Acropora cervicornis and Acropora palmata) currently listed as threatened under the US Endangered Species Act (ESA) (Federal Register/Vol. 71, No. 129/Thursday, July 6, 2006 / Rules and Regulations, http://www.gpo.gov/fdsys/pkg/FR-2006-07-06/pdf/06-6017.pdf) and seven additional stony coral species which have been petitioned for listing as endangered or threatened under the ESA (Agaricia lamarcki, Dendrogyra cylindrus, Dichocoenia stokesii, Montastraea annularis, Montastraea faveolata, Montastraea franksi, and Mycetophyllia ferox) (Federal Register/Vol. 75, No. 27/Wednesday, February 10, 2010/Proposed Rules, http://www.nmfs.noaa.gov/pr/pdfs/fr/fr75-6616.pdf). This report also summarizes the abundance and distribution of small recreational vessel anchors observed within the study area for this survey effort. This effort was guided by the NOAA Fisheries Service’s recommended survey protocol (http://sero.nmfs.noaa.gov/pr/pdf/RecommendedSurveyProtocolforAcropora.pdf). This protocol was designed for surveying the distribution and abundance of Acropora spp. utilizing a 2-tiered survey approach. The protocol recommends data collection at 1 sampling site per every 10,000 m² within the project area. The first tier is a rapid assessment of the site to locate any occurrences of Acropora spp. The second tier is a more comprehensive effort designed to provide greater detail on colony abundance, size, and condition. If five or more Acropora colonies are identified during the tier 1 effort, a tier 2 effort is conducted. The seven candidate species were also included in the tier 1 sampling effort. No tier 2 effort was conducted for the seven candidate species. The number of small recreational vessel anchors seen during the tier 1 effort was also included. The project area included eight coral reef habitats found in depths less than 30m (Walker et al. 2008). These habitats included, from nearshore to offshore: colonized pavement-shallow, ridge shallow, inner linear reef, middle linear reef, colonized pavement-deep, outer linear reef, spur and groove, and aggregated patch reefs. Within these habitats in the project area, 376 sites were sampled (tier 1 sites). No Acropora palmata colonies were identified during this effort. Acropora cervicorniswas identified within 45 of the 376 tier 1 sites. A majority of these sites were within the nearshore habitats (colonized pavement-shallow, ridge-shallow, and inner linear reef) in depths less than 10m. Of these 45 sites, 29 had more than five colonies identified and were included in the tier 2 effort. All seven candidate species were identified at the tier 1 sites within the project area during the effort: Dichocoenia stokesii (344 sites), Montastraea faveolata (291 sites), Agaricia lamarcki (155 sites), Montastraea annularis (85 sites); Montastraea franksi (74 sites), Mycetophyllia ferox (24 sites), and Dendrogyra cylindrus (4 sites). D. stokesii was abundant in all habitats with more than five colonies identified in 228 sites. The middle reef supported the highest abundance of M. faveolata. More than five colonies of M. faveolatawere identified in 188 sites, and 11 sites had more than 50 colonies identified. A. lamarkicolonies were identified at nearly all of the colonized pavement-deep, outer reef, spur and groove, and aggregated patch reef; no colonies were identified in the nearshore colonized pavement-shallow and ridge-shallow habitats. Fifty sites had more than five colonies identified, and 29 sites had more than 10 colonies identified. Fourteen sites supported more than five colonies of M. annularis, and four sites in the middle linear reef habitat had more than 10 colonies identified. M. franksi colonies were identified in all habitats except the ridge shallow habitat; more than five colonies of M. franksi were identified in 15 sites, and the middle linear reef supported the highest abundance of colonies. More than five colonies of D. cylindricus and M. feroxwere not identified in any of the 376 tier one sites during the survey. Anchors were counted at 149 of the 376 tier 1 sites. Anchors were observed in all eight habitats. The maximum number of anchors seen at one site was eight, and 65 sites had two or more anchors

    Determining the Extent and Characterizing Coral Reef Habitats of the Northern Latitudes of the Florida Reef Tract (Martin County)

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    Climate change has recently been implicated in poleward shifts of many tropical species including corals; thus attention focused on higher-latitude coral communities is warranted to investigate possible range expansions and ecosystem shifts due to global warming. As the northern extension of the Florida Reef Tract (FRT), the third-largest barrier reef ecosystem in the world, southeast Florida (25–27° N latitude) is a prime region to study such effects. Most of the shallow-water FRT benthic habitats have been mapped, however minimal data and limited knowledge exist about the coral reef communities of its northernmost reaches off Martin County. First benthic habitat mapping was conducted using newly acquired high resolution LIDAR bathymetry and aerial photography where possible to map the spatial extent of coral reef habitats. Quantitative data were collected to characterize benthic cover and stony coral demographics and a comprehensive accuracy assessment was performed. The data were then analyzed in a habitat biogeography context to determine if a new coral reef ecosystem region designation was warranted. Of the 374 km2 seafloor mapped, 95.2% was Sand, 4.1% was Coral Reef and Colonized Pavement, and 0.7% was Other Delineations. Map accuracy assessment yielded an overall accuracy of 94.9% once adjusted for known map marginal proportions. Cluster analysis of cross-shelf habitat type and widths indicated that the benthic habitats were different than those further south and warranted designation of a new coral reef ecosystem region. Unlike the FRT further south, coral communities were dominated by cold-water tolerant species and LIDAR morphology indicated no evidence of historic reef growth during warmer climates. Present-day hydrographic conditions may be inhibiting poleward expansion of coral communities along Florida. This study provides new information on the benthic community composition of the northern FRT, serving as a baseline for future community shift and range expansion investigations

    Altering HIF-1α through 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure affects coronary vessel development.

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    Differential tissue hypoxia drives normal cardiogenic events including coronary vessel development. This requirement renders cardiogenic processes potentially susceptible to teratogens that activate a transcriptional pathway that intersects with the hypoxia-inducible factor (HIF-1) pathway. The potent toxin 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is known to cause cardiovascular defects by way of reduced myocardial hypoxia, inhibition of angiogenic stimuli, and alterations in responsiveness of endothelial cells to those stimuli. Our working hypothesis is that HIF-1 levels and thus HIF-1 signaling in the developing myocardium will be reduced by TCDD treatment in vivo during a critical stage and in particularly sensitive sites during heart morphogenesis. This inadequate HIF-1 signaling will subsequently result in outflow tract (OFT) and coronary vasculature defects. Our current data using the chicken embryo model showed a marked decrease in the intensity of immunostaining for HIF-1α nuclear expression in the OFT myocardium of TCDD-treated embryos. This area at the base of the OFT is particularly hypoxic during normal development; where endothelial cells initially form a concentrated anastomosing network known as the peritruncal ring; and where the left and right coronary arteries eventually connect to the aortic lumen. Consistent with this finding, anomalies of the proximal coronaries were detected after TCDD treatment and HIF-1α protein levels decreased in a TCDD dose-dependent manner

    Health Disparities Among Racial and Ethnic Minority Firefighters

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    ABSTRACT Background: Racial/ethnic minorities are substantially underrepresented in the fire service and this situation is unique when compared to similarly mentally and physically demanding and hazardous occupations such as the military and law enforcement. There is little systematic research to provide greater clarity about this significant disparity. The purpose of this study is to examine physical and behavioral health issues of racial/ethnic minority firefighters when compared to their white, non-Hispanic counterparts and potentially identify areas for future research that might assist in improving their substantial underrepresentation. Materials and Methods: We report the results of a secondary analysis of data combining the baseline evaluations of two different firefighter health studies, the Firefighter Injury and Risk Evaluation (FIRE) and Fuel 2 Fight (F2F) studies. Male career firefighters (N=1,404) were from 31 fire departments across the US and its territories. White, non-Hispanic firefighters comprised 72.5% of the sample (n=1,018) and 27.5% classified themselves as a racial/ethnic minority. Firefighters who agreed to participate comprised 94% (F2F) and 97% (FIRE) of those available and all underwent assessments including body composition, fitness, and general/behavioral health, and job satisfaction. Results: We examined differences in health and job status between minority and non-minority firefighters and between firefighters in minority- (MDCs) and white-dominated communities (WDCs). After adjusting for potential confounds, there were significant main effects for the individual minority status vs. non-minority status on both BMI and BF%, indicating that minority firefighters had significantly higher average BMI (28.8±0.3kg/m2) and BF% (24.7± 0.7%) when compared to their white, non-Hispanic colleagues (27.7±0.2kg/m2and 23.1±0.6% for BMI and BF%, respectively). Minority firefighters also were 59% more likely to be obese (adjusted [A]OR=1.59; 95% CI=1.16-2.18). Firefighters serving in MDCs reported significantly more poor health days (Mean±SE; 3.2±0.2 days) than firefighters serving in WDCs (2.8±0.2 days; p=0.038). In addition, minority firefighters reported significantly more poor health days (3.6±0.4 days) than their non-minority colleagues (2.8±0.2 days; p=0.003), while the interaction indicates that minority firefighters in MDCs reported more poor health days than the other groups (p Conclusions: Individual and community minority status (i.e., ethnic density effect) were both significantly associated with a number of important health status indicators, with racial/ethnic minority firefighters demonstrating greater risk for unfavorable body composition and more poor physical health days. In addition, minority firefighters in WDCs reported the highest prevalence of lifetime diagnosis of depression by a physician, while minority firefighters in MDCs had the lowest. Many of these health status indicators have recently been studied within the context of experiences with discrimination, demonstrating that racial discrimination is associated with greater risk for obesity, depression, and poor physical and mental health and could be contributing to health disparities and potentially negatively impacting racial/ethnic minority firefighter health, safety, and retention

    Laboratory and field strength of mine waste rock

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    LIDAR-Derived Benthic Habitat Maps Enable the Quantification of Potential Dredging Impacts to Coral Reef Ecosystems

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    An essential component to the analysis of ecosystem services is to characterize and define the major habitats within the area of interest. Aerial photography and/or satellite imagery coupled with geographic information systems (GIS) are frequently used to identify and quantify habitats in open terrestrial ecosystems. However, it is more difficult to successfully apply this methodology to deeper, \u3c20 m, underwater environments. Light detection and ranging (LIDAR), a relatively new remote sensing technology that provides detailed bathymetry, can be used when adequate imagery is not available. This study uses LIDAR as the basis to characterize various benthic habitats in a coral reef ecosystem in order to quantify the habitats for a Habitat Equivalency Analysis (HEA) related to planned dredging activities to expand the Port Everglades entrance channel, Broward County, FL. As part of a regional mapping effort, marine benthic habitats were characterized for Broward County, FL. A mosaic of interpolated, sunshaded, laser bathymetry data served as the foundation upon which acoustic ground discrimination, limited subbottom profiling and aerial photography, and groundtruthing data were added in a GIS to aid in interpretation of benthic habitats. Expert-driven visual interpretation outlined geomorphological features in the LIDAR data at a scale of 1:6000 with a minimum mapping unit of 1 acre. The map of Broward County yielded a high overall accuracy of 89.6%. To quantify the potential dredging impacts, the habitat layer was clipped in GIS to the boundaries of anticipated direct and indirect impacts of the proposed project. Then the area of each clipped polygon was totaled for each habitat by impact type. HEA and Florida’s Uniform Mitigation Assessment Method (UMAM) were performed using these areas. This work would not have been possible using satellite imagery or aerial photography alone and illustrates the capability of relatively new remote sensing technologies to aid in the definition and quantification of habitats for ecosystem service analyses

    Plant Community Changes Over 54 Years Within the Great Basin Experimental Range, Manti-La Sal National Forest

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    Plant community changes and natural succession over time impact forage values, watershed quality, wildlife habitat, and ecosystem dynamics. Comparisons were made between a vegetation map of community types completed in 1937 by the U.S. Forest Service, and vegetation maps compiled in 1990 of the same areas by satellite imagery, and through 1991 areal photo interpretation combined with ground truthing. The study area includes nearly all of the drainage in Ephraim Canyon located in central Utah which consists of 6,027 acres (2,439 ha). Elevation ranges from 6,600 to 10,400 feet (2,040 to 3,210 m). Vegetation types ranged from pinyon-juniper woodland through oakbrush, mountain shrub, aspen, conifer and subalpine herbland. The comparison showed significant plant community changes and successional trends over the 54 year period
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