1,867 research outputs found
A method for estimating the rate of shedding of tags from yellowfin tuna
ENGLISH: The present paper describes a new method for estimating the shedding rate of tags. The method utilizes not only data on tagging and recovery of fish marked with two tags but also data from those marked with one. One important advantage of the new technique is that the estimates of the shedding rates are free from distortion caused by variations in fishing intensity during the total recovery period. The idea of this method appears to be implicit in a short note by Gulland (1963). This technique has been applied to the data obtained by the Inter-American Tropical Tuna Commission in a tagging cruise off the west coast of southern Baja California, during June 1963, at which time both single and double-tagged yellowfin tuna were released. Details of the tagging procedure and equipment have been described by Fink (1965b). The results presented in the present paper are for yellowfin tuna tagged with dart tags. Estimates of shedding should be made separately for each species investigated and also for each type of tag used, since these rates may be variable and often unexpectedly high (Springer and McErlean 1961, Chadwick 1963).
SPANISH: El presente estudio describe un nuevo método para estimar las tasas del desprendimiento de marcas. El método emplea no solamente los datos sobre la marcación y recobro de peces marcados con dos marcas, pero también datos de los peces marcados con una marca. Una ventaja importante de la nueva técnica, es que las estimaciones de las tasas de desprendimiento son libres de alteración, causada por las variaciones en la intensidad de pesca durante el período total de recobro. La idea de este método parece ser implícita en un breve apunte por Gulland (1963). Esta técnica se ha aplicado a los datos obtenidos por la Comisión Interamericana del Atún Tropical, en un crucero de marcación efectuado frente a la costa occidental al sur de Baja California, en junio de 1963, tiempo en el cual fueron liberados atunes aleta amarilla marcados tanto con una como con dos marcas. Los detalles del procedimiento de la marcación y del equipo usado han sido descritos por Fink (1965b). Los resultados presentados en este estudio, pertenecen al atún aleta amarilla marcado con marcas de dardo. Las estimaciones del desprendimiento deben efectuarse separadamente para cada especie que ha sido investigada y también para cada tipo de marca usado, ya que estas tasas pueden ser vaiables, y a menudo inesperadamente altas (Springer y McErlean 1961, Chadwick 1963).
(PDF contains 20 pages.
A method for estimating the rate of shedding of tags from yellowfin tuna
ENGLISH: The present paper describes a new method for estimating the shedding rate of tags. The method utilizes not only data on tagging and recovery of fish marked with two tags but also data from those marked with one. One important advantage of the new technique is that the estimates of the shedding rates are free from distortion caused by variations in fishing intensity during the total recovery period. The idea of this method appears to be implicit in a short note by Gulland (1963). This technique has been applied to the data obtained by the Inter-American Tropical Tuna Commission in a tagging cruise off the west coast of southern Baja California, during June 1963, at which time both single and double-tagged yellowfin tuna were released. Details of the tagging procedure and equipment have been described by Fink (1965b). The results presented in the present paper are for yellowfin tuna tagged with dart tags. Estimates of shedding should be made separately for each species investigated and also for each type of tag used, since these rates may be variable and often unexpectedly high (Springer and McErlean 1961, Chadwick 1963).
SPANISH: El presente estudio describe un nuevo método para estimar las tasas del desprendimiento de marcas. El método emplea no solamente los datos sobre la marcación y recobro de peces marcados con dos marcas, pero también datos de los peces marcados con una marca. Una ventaja importante de la nueva técnica, es que las estimaciones de las tasas de desprendimiento son libres de alteración, causada por las variaciones en la intensidad de pesca durante el período total de recobro. La idea de este método parece ser implícita en un breve apunte por Gulland (1963). Esta técnica se ha aplicado a los datos obtenidos por la Comisión Interamericana del Atún Tropical, en un crucero de marcación efectuado frente a la costa occidental al sur de Baja California, en junio de 1963, tiempo en el cual fueron liberados atunes aleta amarilla marcados tanto con una como con dos marcas. Los detalles del procedimiento de la marcación y del equipo usado han sido descritos por Fink (1965b). Los resultados presentados en este estudio, pertenecen al atún aleta amarilla marcado con marcas de dardo. Las estimaciones del desprendimiento deben efectuarse separadamente para cada especie que ha sido investigada y también para cada tipo de marca usado, ya que estas tasas pueden ser vaiables, y a menudo inesperadamente altas (Springer y McErlean 1961, Chadwick 1963).
(PDF contains 20 pages.
A population of z> 2 far-infrared Herschel-spire-selected starbursts
We present spectroscopic observations for a sample of 36 Herschel-SPIRE
250-500um selected galaxies (HSGs) at 2<z<5 from the Herschel Multi-tiered
Extragalactic Survey (HerMES). Redshifts are confirmed as part of a large
redshift survey of Herschel-SPIRE-selected sources covering ~0.93deg^2 in six
extragalactic legacy fields. Observations were taken with the Keck I Low
Resolution Imaging Spectrometer (LRIS) and the Keck II DEep Imaging
Multi-Object Spectrograph (DEIMOS). Precise astrometry, needed for
spectroscopic follow-up, is determined by identification of counterparts at
24um or 1.4GHz using a cross-identification likelihood matching method.
Individual source luminosities range from log(L_IR/Lsun)=12.5-13.6
(corresponding to star formation rates 500-9000Msun/yr, assuming a Salpeter
IMF), constituting some of the most intrinsically luminous, distant infrared
galaxies yet discovered. We present both individual and composite rest-frame
ultraviolet spectra and infrared spectral energy distributions (SEDs). The
selection of these HSGs is reproducible and well characterized across large
areas of sky in contrast to most z>2 HyLIRGs in the literature which are
detected serendipitously or via tailored surveys searching only for high-z
HyLIRGs; therefore, we can place lower limits on the contribution of HSGs to
the cosmic star formation rate density at (7+-2)x10^(-3)Msun/yr h^3Mpc^(-3) at
z~2.5, which is >10% of the estimated total star formation rate density (SFRD)
of the Universe from optical surveys. The contribution at z~4 has a lower limit
of 3x10^(-3)Msun/yr h^3 Mpc^(-3), ~>20% of the estimated total SFRD. This
highlights the importance of extremely infrared-luminous galaxies with high
star formation rates to the build-up of stellar mass, even at the earliest
epochs.Comment: 25 pages, 10 figures; ApJ accepte
HerMES: Current Cosmic Infrared Background Estimates Can be Explained by Known Galaxies and their Faint Companions at z < 4
We report contributions to cosmic infrared background (CIB) intensities
originating from known galaxies and their faint companions at submillimeter
wavelengths. Using the publicly-available UltraVISTA catalog, and maps at 250,
350, and 500 {\mu}m from the \emph{Herschel} Multi-tiered Extragalactic Survey
(HerMES), we perform a novel measurement that exploits the fact that
uncatalogued sources may bias stacked flux densities --- particularly if the
resolution of the image is poor --- and intentionally smooth the images before
stacking and summing intensities. By smoothing the maps we are capturing the
contribution of faint (undetected in K_S ~ 23.4) sources that are physically
associated, or correlated, with the detected sources. We find that the
cumulative CIB increases with increased smoothing, reaching 9.82 +- 0.78, 5.77
+- 0.43, and 2.32 +- 0.19 at 250, 350, and 500 {\mu}m
at 300 arcsec FWHM. This corresponds to a fraction of the fiducial CIB of 0.94
+- 0.23, 1.07 +- 0.31, and 0.97 +- 0.26 at 250, 350, and 500 {\mu}m, where the
uncertainties are dominated by those of the absolute CIB. We then propose, with
a simple model combining parametric descriptions for stacked flux densities and
stellar mass functions, that emission from galaxies with log(M/Msun) > 8.5 can
account for the most of the measured total intensities, and argue against
contributions from extended, diffuse emission. Finally, we discuss prospects
for future survey instruments to improve the estimates of the absolute CIB
levels, and observe any potentially remaining emission at z > 4.Comment: Accepted to ApJL. 6 Pages, 3 figure
The frequency of CD127low expressing CD4+CD25high T regulatory cells is inversely correlated with human T lymphotrophic virus type-1 (HTLV-1) proviral load in HTLV-1-infection and HTLV-1-associated myelopathy/tropical spastic paraparesis
<p>Abstract</p> <p>Background</p> <p>CD4<sup>+</sup>CD25<sup>high </sup>regulatory T (T<sub>Reg</sub>) cells modulate antigen-specific T cell responses, and can suppress anti-viral immunity. In HTLV-1 infection, a selective decrease in the function of T<sub>Reg </sub>cell mediated HTLV-1-tax inhibition of FOXP3 expression has been described. The purpose of this study was to assess the frequency and phenotype of T<sub>Reg </sub>cells in HTLV-1 asymptomatic carriers and in HTLV-1-associated neurological disease (HAM/TSP) patients, and to correlate with measures of T cell activation.</p> <p>Results</p> <p>We were able to confirm that HTLV-I drives activation, spontaneous IFNγ production, and proliferation of CD4+ T cells. We also observed a significantly lower proportion of CTLA-4<sup>+ </sup>T<sub>Reg </sub>cells (CD4<sup>+</sup>CD25<sup>high </sup>T cells) in subjects with HAM/TSP patients compared to healthy controls. Ki-67 expression was negatively correlated to the frequency of CTLA-4<sup>+ </sup>T<sub>Reg </sub>cells in HAM/TSP only, although Ki-67 expression was inversely correlated with the percentage of CD127<sup>low </sup>T<sub>Reg </sub>cells in healthy control subjects. Finally, the proportion of CD127<sup>low </sup>T<sub>Reg </sub>cells correlated inversely with HTLV-1 proviral load.</p> <p>Conclusion</p> <p>Taken together, the results suggest that T<sub>Reg </sub>cells may be subverted in HAM/TSP patients, which could explain the marked cellular activation, spontaneous cytokine production, and proliferation of CD4<sup>+ </sup>T cells, in particular those expressing the CD25<sup>high</sup>CD127<sup>low </sup>phenotype. T<sub>Reg </sub>cells represent a potential target for therapeutic intervention for patients with HTLV-1-related neurological diseases.</p
Location Preferences of Family Firms: Strategic Decision Making or “Home Sweet Home”?
Selecting a business location is among the most important strategic decisions for family firms. Yet the separate demands of the family and the business often prove difficult to balance. A comparison of location preferences in family and nonfamily firms provides insight into the family influence on strategic decision making.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67069/2/10_1111_j_1741-6248_1992_00271_x.pd
Comparison of prestellar core elongations and large-scale molecular cloud structures in the Lupus 1 region
Turbulence and magnetic fields are expected to be important for regulating molecular cloud formation and evolution. However, their effects on sub-parsec to 100 parsec scales, leading to the formation of starless cores, are not well understood. We investigate the prestellar core structure morphologies obtained from analysis of the Herschel-SPIRE 350 mum maps of the Lupus I cloud. This distribution is first compared on a statistical basis to the large-scale shape of the main filament. We find the distribution of the elongation position angle of the cores to be consistent with a random distribution, which means no specific orientation of the morphology of the cores is observed with respect to the mean orientation of the large-scale filament in Lupus I, nor relative to a large-scale bent filament model. This distribution is also compared to the mean orientation of the large-scale magnetic fields probed at 350 mum with the Balloon-borne Large Aperture Telescope for Polarimetry during its 2010 campaign. Here again we do not find any correlation between the core morphology distribution and the average orientation of the magnetic fields on parsec scales. Our main conclusion is that the local filament dynamics---including secondary filaments that often run orthogonally to the primary filament---and possibly small-scale variations in the local magnetic field direction, could be the dominant factors for explaining the final orientation of each core
Trends and determinants of excess winter mortality in New Zealand: 1980 to 2000
<p>Abstract</p> <p>Background</p> <p>Although many countries experience an increase in mortality during winter, the magnitude of this increase varies considerably, suggesting that some winter excess may be avoidable. Conflicting evidence has been presented on the role of gender, region and deprivation. Little has been published on the magnitude of excess winter mortality (EWM) in New Zealand (NZ) and other Southern Hemisphere countries.</p> <p>Methods</p> <p>Monthly mortality rates per 100,000 population were calculated from routinely collected national mortality data for 1980 to 2000. Generalised negative binomial regression models were used to compare mortality rates between winter (June–September) and the warmer months (October–May).</p> <p>Results</p> <p>From 1980–2000 around 1600 excess winter deaths occurred each year with winter mortality rates 18% higher than expected from non-winter rates. Patterns of EWM by age group showed the young and the elderly to be particularly vulnerable. After adjusting for all major covariates, the winter:non-winter mortality rate ratio from 1996–2000 in females was 9% higher than in males. Mortality caused by diseases of the circulatory system accounted for 47% of all excess winter deaths from 1996–2000 with mortality from diseases of the respiratory system accounting for 31%. There was no evidence to suggest that patterns of EWM differed by ethnicity, region or local-area based deprivation level. No decline in seasonal mortality was evident over the two decades.</p> <p>Conclusion</p> <p>EWM in NZ is substantial and at the upper end of the range observed internationally. Interventions to reduce EWM are important, but the surprising lack of variation in EWM by ethnicity, region and deprivation, provides little guidance for how such mortality can be reduced.</p
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