1,026 research outputs found
Trends in Annual Survival of Steller’s Eiders Molting at Izembek Lagoon on the Alaska Peninsula, 1993–2006
Izembek Lagoon, located on the Alaska Peninsula, is an important molting area for the Pacific population of Steller’s Eiders (Polysticta stelleri) and was the site of consistent banding effort during 1993–2006. We used Pradel mark-recapture models to estimate annual survival and population growth rates for adult Steller’s Eiders molting at Izembek Lagoon. We designed 32 models that included effects of sex and year on survival, recapture rate, and seniority, as well as potential trends in survival and seniority. The top model incorporated a two-phase trend (1993–98, 1999–2003) in survival and seniority for each sex and fully sex- and year-specific recapture rates. Average annual adult survival was estimated at 0.86 (SE = 0.030) for females and 0.87 (SE = 0.018) for males. Average annual population growth rates since 1998 were estimated to be approximately 1.0 for both sexes. A brief warming event in the Pacific Decadal Oscillation (1997–98) coincided with the lowest estimates of annual survival, while a subsequent return to cooler conditions in the Bering Sea coincided with the highest estimates and an increasing trend in annual survival.La lagune d’Izembek, située dans la péninsule de l’Alaska, constitue une aire de mue importante pour la population d’eiders de Steller (Polysticta stelleri) du Pacifique. Elle a fait l’objet de travaux de baguage soutenus entre 1993 et 2006. Nous nous sommes servis des modèles de marquage et de recapture de Pradel pour estimer les taux de survie et d’accroissement de la population d’eiders de Steller adultes en période de mue à la lagune d’Izembek. Nous avons conçu 32 modèles qui compre-naient les effets du sexe et de l’année sur le taux de survie, le taux de recapture et l’ancienneté. Le meilleur des modèles comprenait une tendance diphasique (de 1993 à 1998, et de 1999 à 2003) en ce qui a trait aux taux de survie et d’ancienneté de chacun des sexes ainsi qu’en ce qui a trait aux taux de recapture entièrement en fonction du sexe et de l’année. Chez les adultes, le taux de survie moyen était estimé à 0,86 (SE = 0,030) pour la femelle et à 0,87 (SE = 0,018) pour le mâle. Depuis 1998, les taux annuels d’accroissement de la population étaient estimés à environ 1,0 dans le cas des deux sexes. Un bref événement de réchauffement dans l’oscillation décadaire du Pacifique (1997-1998) a coïncidé avec les estimations de survie annuelles les plus faibles, tandis que le retour de conditions plus fraîches dans la mer de Béring a coïncidé avec les estimations les plus élevées ainsi qu’à une tendance à la hausse du taux de survie annuel
Transplantation of Human Neuroblastoma Cells, Catecholaminergic and Non-Catecholaminergic: Effects on Rotational Behavoir in Parkinson's Rat Model
Cultured human catecholaminergic and noncatecholaminergic
donor cells were used in
neural transplantation experiments in a rat
model of Parkinson's disease. Using two different
human catecholaminergic neuroblastoma cell
lines, one control non-catecholaminergic neuroblastoma
cell line, and one sham control (tissue
culture medium), transplants were made into the
striatum using a modified Ungerstedt
hemiparkinsonian rat model. Significant
decreases in apomorphine-induced rotational
behavior were produced by two of three
catecholaminergic cell lines. Grafted cells staining
positively for tyrosine hydroxylase (TH) and
catecholamine fluorescence indicated viable catecholamine
activity in the two cell lines which produced
reductions in rotational behavior.
Catecholamine fluorescence was not detected in
either of the two controls. These data suggest a
link between catecholamine secretion by transplanted
cells and motor improvement using a rat
rotational behavior model
A Phase III Randomized Trial of Gemcitabine–Oxaliplatin versus Carboplatin–Paclitaxel as First-Line Therapy in Patients with Advanced Non-small Cell Lung Cancer
Purpose:This phase III study compared the efficacy and tolerability of gemcitabine and oxaliplatin (GEMOX) with paclitaxel and carboplatin (PCb) in chemotherapy-naive patients with stage IIIB/IV non-small cell lung cancer.Patients and Methods:Patients aged 18 years or older were randomized to PCb (paclitaxel 225 mg/m2 followed by carboplatin area under the curve = 6 on day 1 every 3 weeks) or GEMOX (gemcitabine 1,000 mg/m2 on days 1 and 8 followed by oxaliplatin 130 mg/m2 on day 1 every 3 weeks) for up to six cycles. The primary end point was progression-free survival (PFS), with tumor response rate, overall survival (OS), and quality of life as secondary end points.Results:The study was terminated after 383 patients had been randomized (371 received treatment) as the incidence of adverse events had exceeded the protocol-specified safety threshold (≥20% in either arm). No formal statistical comparisons were conducted. Median PFS was 4.44 months and 4.67 months in the GEMOX and PCb groups, respectively. Objective response rates (complete or partial) were 15.2% and 22.4% in the GEMOX and PCb arms, respectively. Median OS was 9.90 months (GEMOX) and 9.24 months (PCb); post hoc analyses showed median OS in patients aged 70 years or older to be similar to those younger than 70 years. PFS was similar in both groups of patients with adenocarcinoma histology, although OS favored the GEMOX group. Quality of life was improved from baseline in both groups. Toxicity profiles were comparable between the groups.Conclusion:PFS, OS, and objective response rates with GEMOX were similar to PCb. Nevertheless, toxicities limit the adoption of this regimen for routine use in advanced non-small cell lung cancer
Suzaku Observations of Local Ultraluminous Infrared Galaxies
We report the results from our analysis of {\it Suzaku} XIS (0.5-10 keV) and
HXD/PIN (15-40 keV) observations of five well-known local ULIRGs: {\em IRAS}
F05189-2524, {\em IRAS} F08572+3915, Mrk 273, PKS 1345+12, and Arp 220. The XIS
observations of F05189-2524 and Mrk 273 reveal strong iron lines consistent
with Fe K and changes in spectral shapes with respect to previous {\it
Chandra} and {\it XMM-Newton} observations. Mrk 273 is also detected by the
HXD/PIN at 1.8-. For F05189-2524, modeling of the data from the
different epochs suggests that the change in spectral shape is likely due to
the central source switching off, leaving behind a residual reflection
spectrum, or an increase in the absorbing column. An increase in the covering
fraction of the absorber can describe the spectral variations seen in Mrk 273,
although a reduction in the intrinsic AGN luminosity cannot be formally ruled
out. The {\it Suzaku} spectra of Mrk 273 are well fit by a ~94% covering
fraction model with a column density of cm. The
absorption-corrected log[ / ] ratio is consistent
with those found in PG Quasars. The 0.5-10 keV spectrum of PKS 1345+12 and Arp
220 seem unchanged from previous observations and their hard X-ray emission is
not convincingly detected by the HXD/PIN. The large column density derived from
CO observations and the large equivalent width of an ionized Fe line in Arp 220
can be reconciled by an ionized reflection model. F08572+3915 is undetected in
both the XIS and HXD/PIN, but the analysis of unpublished {\em Chandra} data
provides a new measurement at low energies.Comment: 37 pages including 4 tables and 10 figures. Accepted for publication
in ApJ. It is tentatively scheduled to appear in the January 20, 2009 issue
of Ap
Economic inequalities in the effectiveness of a primary care intervention for depression and suicidal ideation.
BACKGROUND: Economic disadvantage is associated with depression and suicide. We sought to determine whether economic disadvantage reduces the effectiveness of depression treatments received in primary care. METHODS: We conducted differential-effects analyses of the Prevention of Suicide in Primary Care Elderly: Collaborative Trial, a primary-care-based randomized, controlled trial for late-life depression and suicidal ideation conducted between 1999 and 2001, which included 514 patients with major depression or clinically significant minor depression. RESULTS: The intervention effect, defined as change in depressive symptoms from baseline, was stronger among persons reporting financial strain at baseline (differential effect size = -4.5 Hamilton Depression Rating Scale points across the study period [95% confidence interval = -8.6 to -0.3]). We found similar evidence for effect modification by neighborhood poverty, although the intervention effect weakened after the initial 4 months of the trial for participants residing in poor neighborhoods. There was no evidence of substantial differences in the effectiveness of the intervention on suicidal ideation and depression remission by economic disadvantage. CONCLUSIONS: Economic conditions moderated the effectiveness of primary-care-based treatment for late-life depression. Financially strained individuals benefited more from the intervention; we speculate this was because of the enhanced treatment management protocol, which led to a greater improvement in the care received by these persons. People living in poor neighborhoods experienced only temporary benefit from the intervention. Thus, multiple aspects of economic disadvantage affect depression treatment outcomes; additional work is needed to understand the underlying mechanisms
Simultaneous Chandra and RXTE Spectroscopy of the Microquasar H~1743-322: Clues to Disk Wind and Jet Formation from a Variable Ionized Outflow
We observed the bright phase of the 2003 outburst of the Galactic black hole
candidate H 1743-322 in X-rays simultaneously with Chandra and RXTE on four
occasions. The Chandra/HETGS spectra reveal narrow, variable (He-like) Fe XXV
and (H-like) Fe XXVI resonance absorption lines. In the first observation, the
Fe XXVI line has a FWHM of 1800 +/- 400 km/s and a blue-shift of 700 +/- 200
km/s, suggesting that the highly ionized medium is an outflow. Moreover, the Fe
XXV line is observed to vary significantly on a timescale of a few hundred
seconds in the first observation, which corresponds to the Keplerian orbital
period at approximately 1 E+4 gravitational radii. Our models for the
absorption geometry suggest that a combination of geometric effects and
changing ionizing flux are required to account for the large changes in line
flux observed between observations, and that the absorption likely occurs at a
radius less than 1 E+4 radii for a 10 Msun black hole. Viable models for the
absorption geometry include cyclic absorption due to an accretion disk
structure, absorption in a clumpy outflowing disk wind, or possibly a
combination of these two. If the wind in H 1743-322 has unity filling factor,
the highest implied mass outflow rate is 20 percent of the Eddington mass
accretion rate. This wind may be a hot precursor to the Seyfert-like,
outflowing "warm absorber" geometries recently found in the Galactic black
holes GX 339-4 and XTE J1650-500. We discuss these findings in the context of
ionized Fe absorption lines found in the spectra of other Galactic sources, and
connections to warm absorbers, winds, and jets in other accreting systems.Comment: 18 pages, 7 figures, 5 in color, subm. to ApJ. Uses emulateapj.sty
and apjfonts.st
Evidence for Black Hole Spin in GX 339-4: XMM-Newton EPIC-pn and RXTE Spectroscopy of the Very High State
We have analyzed spectra of the Galactic black hole GX 339-4 obtained through
simultaneous 76 ksec XMM-Newton/EPIC-pn and 10 ksec RXTE observations during a
bright phase of its 2002-2003 outburst. An extremely skewed, relativistic Fe
K-alpha emission line and ionized disk reflection spectrum are revealed in
these spectra. Self-consistent models for the Fe K-alpha emission line profile
and disk reflection spectrum rule-out an inner disk radius compatible with a
Schwarzschild black hole at more than the 8 sigma level of confidence. The
best-fit inner disk radius of 2-3 r_g suggests that GX 339-4 harbors a black
hole with a ~ 0.8-0.9 (where r_g = GM/c^2 and a=cJ/GM^2, and assuming that
reflection in the plunging region is relatively small). This confirms
indications for black hole spin based on a Chandra spectrum obtained later in
the outburst. The emission line and reflection spectrum also rule-out a
standard power-law disk emissivity in GX 339-4; a broken power-law form with
enhanced emissivity inside ~6 r_{g} gives improved fits at more than the 8
sigma level of confidence. The extreme red wing of the line and steep
emissivity require a centrally--concentrated source of hard X-rays which can
strongly illuminate the inner disk. Hard X-ray emission from the base of a jet
- enhanced by gravitational light bending effects - could create the
concentrated hard X-ray emission; this process may be related to magnetic
connections between the black hole and the inner disk. We discuss these results
within the context of recent results from analyses of XTE J1650-500 and
MCG-6-30-15, and models for the inner accretion flow environment around black
holes.Comment: 5 pages, 2 color figures, uses emulateapj.sty and apjfonts.sty, ApJ
Letters, accepte
Recommended from our members
Modeling the role of fomites in a norovirus outbreak
Norovirus accounts for a large portion of the gastroenteritis disease burden, and outbreaks have occurred in a wide variety of environments. Understanding the role of fomites in norovirus transmission will inform behavioral interventions, such as hand washing and surface disinfection. The purpose of this study was to estimate the contribution of fomite-mediated exposures to infection and illness risks in outbreaks. A simulation model in discrete time that accounted for hand-to-porous surfaces, hand-to-nonporous surfaces, hand-to-mouth, -eyes, -nose, and hand washing events was used to predict 17 hr of simulated human behavior. Norovirus concentrations originated from monitoring contamination levels on surfaces during an outbreak on houseboats. To predict infection risk, two dose-response models (fractional Poisson and 2F1 hypergeometric) were used to capture a range of infection risks. A triangular distribution describing the conditional probability of illness given an infection was multiplied by modeled infection risks to estimate illness risks. Infection risks ranged from 70.22% to 72.20% and illness risks ranged from 21.29% to 70.36%. A sensitivity analysis revealed that the number of hand-to-mouth contacts and the number of hand washing events had strong relationships with model-predicted doses. Predicted illness risks overlapped with leisure setting and environmental attack rates reported in the literature. In the outbreak associated with the viral concentrations used in this study, attack rates ranged from 50% to 86%. This model suggests that fomites may have accounted for 25% to 82% of illnesses in this outbreak. Fomite-mediated exposures may contribute to a large portion of total attack rates in outbreaks involving multiple transmission modes. The findings of this study reinforce the importance of frequent fomite cleaning and hand washing, especially when ill persons are present.12 month embargo; published online: 04 Feb 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
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