195 research outputs found
Early postnatal growth of the spotted dolphin, Stenella attenuata, in the offshore Eastern Tropical Pacific.
Estimates of length at birth and early postnatal growth are made for the northern and southern populations of the offshore spotted dolphin in the offshore eastern tropical Pacific. Length at birth is estimated to be 85.4 cm for the northern population and 83.2 cm for the southern population. Analyses of series of monthly distributions of length revealed two cohorts born each year in the northern population, at least in the northern inshore part of its geographic range, but only one cohort born each year in the southern population. Growth curves fitted to the means of the monthly distributions of length gave estimates of
length at 1 year of 126.2 and 132.6 cm and length at 2 years of 154.3 and 154.9 cm for the two cohorts in the northern population. and length at 1 year of 127.9 cm for the southern population. A growth curve fitted to lengths and ages (in dental growth layer groups) from the northern population gave estimates of lengths at 1 and 2 years of 123.0 and 143.0 cm, respectively
Estimates of cetacean abundance in European Atlantic waters in summer
This report summarises design-based estimates of abundance for those cetacean species for which sufficient data were obtained during SCANS-III: harbour porpoise, bottlenose dolphin, Risso’s dolphin, white-beaked dolphin, white-sided dolphin, common dolphin, striped dolphin, pilot whale, all beaked whale species combined, sperm whale, minke whale and fin whale
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Piping elbow irrecoverable pressure loss coefficients for moderately high Reynolds numbers
Test data is described for three different piping elbows. These include 900 elbows with radii of curvature of 12 and 1.5, and a 45{degrees} elbow with a radius of curvature of 1.2. These radii of curvature are sufficiently sharp to cause significant irrecoverable pressure losses to occur. The variation in static wall pressure was measured upstream and downstream of each elbow plus spatially around the elbow itself. Irrecoverable loss coefficients over a range of flows were obtained and correlations for the data are provided. The testing extended the Reynolds number range of the currently existing data base in various handbooks (and other references available in the open literature) by over a factor of five. Comparisons of results to predictions from the correlations of prior studies are provided
Distribution and Abundance of Fin whales and other baleen whales in the European Atlantic
The abundance of fin whales (Balaenoptera physalus) and other baleen whales was generated from data collected during
shipboard sightings surveys as part of the Cetacean Offshore Distribution and Abundance in the European Atlantic project
(CODA). The survey area covered offshore waters beyond the continental shelf of the UK, Ireland, France and Spain. The area
was stratified into four blocks and was surveyed by five ships during July 2007. Double platform methods employing the trialconfiguration
method (BT-method) were used. Fin, sei (B. borealis) and minke whales (B. acutorostrata) were positively
identified, with possible sightings of blue whales (B. musculus). Abundance was estimated for these species and for “large baleen
whales” which included fin, sei, fin/sei and blue whales. Abundance for the larger species was estimated using the Mark-
Recapture Line Transect design-based method and also model-based methods using density surface modelling. Sample size
limitations dictated that conventional line transect sampling methods were used to estimate the abundance of minke whales.
Estimates from the two methods were comparable but model-based methods improved the precision and were considered best
estimates. The density of large baleen whale species was greatest in the southern end of the survey area and water depth,
temperature and distance to the 2000m contour were important predictors of their distribution. The total abundance estimated for
the entire survey area was 9,019 (CV=0.11) fin whales and 9,619 (CV= 0.11) large baleen whales. The uncertainty around these
estimates due to duplicate classification and species identification were explored. The fin whale estimate is likely to be
underestimated because it excludes unidentified large whales, of which a large proportion was likely to have been fin whales.
Notwithstanding this, these large baleen whale abundance estimates are the first robust estimates (corrected for responsive
movement and g(0)) for this area. The estimated abundance of minke whales was 6,765 (CV=0.99) and sightings were restricted
to the northern blocks of the survey area. The minke whale estimate, although imprecise and likely underestimated, does provide a
baseline figure for this area and, when considered with results from the SCANS-II continental shelf surveys of July 2005, gives a
more comprehensive picture of this species in the European Atlantic. These abundance estimates are important contributions to
the conservation and management of these species in the Northeast Atlantic
Gravitational Geometric Phase in the Presence of Torsion
We investigate the relativistic and non-relativistic quantum dynamics of a
neutral spin-1/2 particle submitted an external electromagnetic field in the
presence of a cosmic dislocation. We analyze the explicit contribution of the
torsion in the geometric phase acquired in the dynamic of this neutral
spinorial particle. We discuss the influence of the torsion in the relativistic
geometric phase. Using the Foldy-Wouthuysen approximation, the non-relativistic
quantum dynamics are studied and the influence of the torsion in the
Aharonov-Casher and He-McKellar-Wilkens effects are discussed.Comment: 14 pages, no figur
Abundance of baleen whales in the European Atlantic
The abundance of fin whales (Balaenoptera physalus), sei whales (B. borealis) and minke whales (B. acutorostrata) was estimated
from data collected during shipboard sightings surveys conducted as part of CODA and TNASS (Faroese block) in July 2007 in
offshore waters of the European Atlantic west of the UK, Ireland, France and Spain, combined with data collected from shipboard and
aerial surveys of European Atlantic continental shelf waters conducted as part of SCANS-II in July 2005. Double platform methods
employing the trial-configuration method (BT-method) were used in all shipboard surveys. Analysis used Mark-Recapture Distance
Sampling to account for animals missed on the transect line. Density surface modelling was undertaken to generate model-based
abundance estimates and maps of predicted density. Estimates are presented for the SCANS-II and CODA survey areas. Estimates for
the Faroese block of TNASS have been presented elsewhere.
The abundance of fin whales in the CODA and SCANS-II areas was estimated as 19,354 (CV 0.24) for identified sightings and 29,512
(CV 0.26) when adjusted to include a proportion of unidentified large whale abundance (which included large baleen and sperm
whales), prorated by number of sightings, because there were a large number of such sightings in one of the CODA survey blocks. The
model-based estimate of identified fin whales was 19,751 (CV 0.17), more precise than the design-based estimate. Fin whales were
mainly found in the southern part of the CODA survey area. Estimates based on identified sightings were comparable to those from
the Spanish survey conducted as part of 1989 NASS but were larger if adjusted for a proportion of unidentified large whales. Sei
whales were rare except in the southwest of the survey area; the estimate of abundance was 619 (CV 0.34) for identified sightings and
765 (CV 0.43) adjusted for a proportion of unidentified large whales. Minke whale abundance was estimated for shelf and offshore
European Atlantic waters as 30,410 (CV 0.34). The model-based estimate was less precise and considerably larger
Quadruple abnormal protein aggregates in brainstem pathology and exogenous metal-rich magnetic nanoparticles (and engineered Ti-rich nanorods). The substantia nigrae is a very early target in young urbanites and the gastrointestinal tract a key brainstem portal
Fine particulate air pollution (PM2.5) exposures are linked with Alzheimer's and Parkinson's diseases (AD,PD). AD and PD neuropathological hallmarks are documented in children and young adults exposed lifelong to Metropolitan Mexico City air pollution; together with high frontal metal concentrations (especially iron)–rich nanoparticles (NP), matching air pollution combustion- and friction-derived particles. Here, we identify aberrant hyperphosphorylated tau, ɑ synuclein and TDP-43 in the brainstem of 186 Mexico City 27.29 ± 11.8y old residents. Critically, substantia nigrae (SN) pathology seen in mitochondria, endoplasmic reticulum and neuromelanin (NM) is co-associated with the abundant presence of exogenous, Fe-, Al- and Ti-rich NPs.The SN exhibits early and progressive neurovascular unit damage and mitochondria and NM are associated with metal-rich NPs including exogenous engineered Ti-rich nanorods, also identified in neuroenteric neurons. Such reactive, cytotoxic and magnetic NPs may act as catalysts for reactive oxygen species formation, altered cell signaling, and protein misfolding, aggregation and fibril formation. Hence, pervasive, airborne and environmental, metal-rich and magnetic nanoparticles may be a common denominator for quadruple misfolded protein neurodegenerative pathologies affecting urbanites from earliest childhood. The substantia nigrae is a very early target and the gastrointestinal tract (and the neuroenteric system) key brainstem portals. The ultimate neural damage and neuropathology (Alzheimer's, Parkinson's and TDP-43 pathology included) could depend on NP characteristics and the differential access and targets achieved via their portals of entry. Thus where you live, what air pollutants you are exposed to, what you are inhaling and swallowing from the air you breathe,what you eat, how you travel, and your occupational longlife history are key. Control of NP sources becomes critical. © 2020 Elsevier Inc
On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection
A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)
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