We develop a multi-model approach to explore how abundance of a forage fish (Pacific sardine Sardinops sagax) impacts the ecosystem and predators in the California Current, a region where sardine and ...anchovy Engraulis mordax have recently declined to less than 10% of contemporary peak abundances. We developed or improved applications of 3 ecosystem modeling approaches: Ecopath, Model of Intermediate Complexity for Ecosystem assessment (MICE), and Atlantis. We also used Ecopath diets to predict impacts to predators using a statistical generalization of the dynamic Ecosim model (Predator Response to the Exploitation of Prey PREP). Models that included brown pelican Pelecanus occidentalis at the species level (MICE and Ecopath/PREP) both predict moderate to high vulnerability of brown pelicans to low sardine abundance. This vulnerability arises because sardine comprises a large fraction of their diet, and because other important prey (anchovy) also exhibit large population fluctuations. Two of the ecosystem models (MICE and Atlantis) suggest that California sea lions Zalophus californianus exhibit relatively minor responses to sardine depletion, due to having broader diets and lower reliance on another fluctuating species, anchovy. On the other hand, Ecopath/PREP suggests that sardine declines will have a stronger impact on California sea lions. This discrepancy may in part reflect structural differences in the models: Atlantis and MICE explicitly represent density dependence and age-structure, which can mitigate effects of prey depletion in these models. Future work should identify fisheries management strategies that are robust to uncertainties within and among models, rather than relying on single models to assess ecosystem impacts of management and forage fish abundance.
Effect of waiting time on renal transplant outcome.
Numerous factors are known to impact on patient survival after renal transplantation. Recent studies have confirmed a survival advantage for renal ...transplant patients over those waiting on dialysis. We aimed to investigate the hypothesis that longer waiting times are more deleterious than shorter waiting times, that is, to detect a “dose effect” for waiting time.
We analyzed 73,103 primary adult renal transplants registered at the United States Renal Data System Registry from 1988 to 1997 for the primary endpoints of death with functioning graft and death-censored graft failure by Cox proportional hazard models. All models were corrected for donor and recipient demographics and other factors known to affect outcome after kidney transplantation.
A longer waiting time on dialysis is a significant risk factor for death-censored graft survival and patient death with functioning graft after renal transplantation (P < 0.001 each). Relative to preemptive transplants, waiting times of 6 to 12 months, 12 to 24 months, 24 to 36, 36 to 48, and over 48 months confer a 21, 28, 41, 53, and 72% increase in mortality risk after transplantation, respectively. Relative to preemptive transplants, waiting times of 0 to 6 months, 6 to 12 months, 12 to 24 months, and over 24 months confer a 17, 37, 55, and 68% increase in risk for death-censored graft loss after transplantation, respectively.
Longer waiting times on dialysis negatively impact on post-transplant graft and patient survival. These data strongly support the hypothesis that patients who reach end-stage renal disease should receive a renal transplant as early as possible in order to enhance their chances of long-term survival.
Emergence of a quasar outflow Hamann, F.; Kaplan, K. F.; Hidalgo, P. Rodríguez ...
Monthly notices of the Royal Astronomical Society. Letters,
November 2008, Volume:
391, Issue:
1
Journal Article
Peer reviewed
Open access
We report the first discovery of the emergence of a high-velocity broad-line outflow in a luminous quasar, J105400.40+034801.2, at redshift z∼ 2.1. The outflow is evident in ultraviolet C iv and Si ...iv absorption lines with velocity shifts v∼ 26 300 km s−1 and deblended widths FWHM ∼4000 km s−1. These features are marginally strong and broad enough to be considered broad absorption lines (BALs), but their large velocities exclude them from the standard BAL definition. The outflow lines appeared between two observations in the years 2002.18 and 2006.96. A third observation in 2008.48 showed the lines becoming ∼40 per cent weaker and 10 to 15 per cent narrower. There is no evidence for acceleration or for any outflow gas at velocities ≲23 000 km s−1. The lines appear to be optically thick, with the absorber covering just 20 per cent of the quasar continuum source. This indicates a characteristic absorber size of ∼4 × 1015 cm, but with a BAL-like total column density log NH(cm−2) ≳ 21.2 and average space density nH≳ 2 × 105 cm−3. We attribute the emergence of the outflow lines to a substantial flow structure moving across our line of sight, possibly near the ragged edge of the main BAL flow or possibly related to the onset of a BAL evolutionary phase.
An increasing number of cadaveric kidney transplants are now performed with organs from donors who would have been deemed unsuitable in earlier times. Although good allograft outcomes have been ...obtained with these marginal donor transplants, it is unclear whether recipients of marginal kidney transplants achieve a reduction in long-term mortality as do recipients of "ideal" kidneys. Patients with end-stage renal disease registered on the cadaveric renal transplant waiting list between January 1, 1992, and June 30, 1997, were studied for mortality risks according to three outcomes: wait-listed on dialysis treatment with no transplant (WLD); transplantation with marginal donor kidney (MDK); and "ideal" or optimal donor kidney transplantation (IDK). Thirty-four percent of wait-list registrants had received a cadaveric kidney transplant by June 30, 1998. Of these, 18% received a marginal kidney that had one or more of the following pretransplant factors: donor age >55 yr, non-heartbeating donor, cold ischemia time >36 h, and donor hypertension or diabetes mellitus of > 10 yr duration. Five-year graft and patient survival was 53% and 74% for MDK recipients compared with 67% (P< 0.001) and 80% (P< 0.001) for IDK recipients. Adjusted annual death rate and estimated remaining life time was 6.3%, 4.7%, and 3.3% and 15.3 yr, 20.4 yr, and 28.7 yr for WLD, MDK, and IDK groups, respectively. The average increase in life expectancy for MDK recipients compared with the WLD cohort was 5 yr, although this benefit varied from 3 to 10 yr depending on the recipient's characteristics. It is concluded that transplantation of a marginal kidney is associated with a significant survival benefit when compared with maintenance dialysis.
Abstract
Objective:
This real-life, global study aimed to investigate current views of and clinical practice in the management of COPD and its exacerbations, among clinicians from both the primary ...and secondary care settings.
Methodology:
We devised an online questionnaire about COPD management and invited 13,613 general practitioners (GPs) and respiratory specialists to respond. Participating clinicians, recruited from an established research panel, treated a minimum of 10 (GPs) or 20 (respiratory specialists) patients with COPD per month. Completed responses were collected from 1400 clinicians from 14 countries.
Results:
A third of GPs and respiratory specialists reported that the main goal of COPD management was to improve patients' quality of life; only 14% of GPs thought that the prevention of exacerbations was a priority.
The study showed a strong preference for inhaled corticosteroids in combination with other treatments, rather than as sole therapy, in line with global guidelines. Fewer GPs than respiratory specialists routinely recommended anticholinergics, pulmonary rehabilitation or oxygen therapy.
Clinicians reported that 55% (GPs) and 57% (respiratory specialists) of their COPD patients had experienced an exacerbation in the previous 12 months. Although higher than those reported in clinical trials, these rates were lower than patients' own estimates from a corresponding patient survey, even in mild COPD patients (62%; 80% in severe patients). Despite this, 74% of GPs and 67% of respiratory physicians reported satisfaction with therapies to prevent exacerbations.
Conclusions:
This global survey revealed that clinicians' main goal when managing COPD was to improve the lives of their patients, and that few viewed reducing exacerbations as a priority. Despite a relatively high level of adherence to treatment recommendations, it appears that clinicians, particularly GPs, underestimate the frequency and impact of exacerbations. These results suggest a need to raise awareness of exacerbations among both GPs and respiratory specialists.
Simultaneous pancreas-kidney transplantation (SPK) ameliorates the progression of microvascular diabetic complications but the procedure is associated with excess initial morbidity and an uncertain ...effect on patient survival when compared with solitary cadaveric or living donor renal transplantation. We evaluated mortality risks associated with SPK, solitary renal transplantation, and dialysis treatment in a national cohort of type 1 diabetics with end-stage nephropathy.
A total of 13,467 adult-type 1 diabetics enrolled on the renal and renal-pancreas transplant waiting list between 10/01/88 and 06/30/97 were followed until 06/30/98. Time-dependent mortality risks and life expectancy were calculated according to the treatment received subsequent to wait-list registration: SPK; cadaveric kidney only (CAD); living donor kidney only (LKD) transplantation; and dialysis wait-listed, maintenance dialysis treatment (WLD).
Adjusted 10-year patient survival was 67% for SPK vs. 65% for LKD recipients (P=0.19) and 46% for CAD recipients (P<0.001). The excess initial mortality normally associated with renal transplantation and the risk of early infectious death was 2-fold higher in SPK recipients. The time to achieve equal proportion of survivors as the WLD patients was 170, 95, and 72 days for SPK, CAD, and LKD recipients, respectively (P<0.001). However, the adjusted 5-year morality risk (RR) using WLD as the reference and the expected remaining life years were 0.40, 0.45, and 0.75 and 23.4, 20.9, and 12.6 years for SPK, LKD, and CAD, respectively. There was no survival benefit in SPK recipients > or =50 years old (RR=1.38, P=0.81).
Among patients with type 1 DM with end-stage nephropathy, SPK transplantation before the age of 50 years was associated with long-term improvement in survival compared to solitary cadaveric renal transplantation or dialysis.
Context
.
Measuring the abundances of neutron-capture elements in Galactic disk stars is an important part of understanding key stellar and galactic processes. In the optical wavelength regime a ...number of different neutron-capture elements have been measured; however, only the s-process-dominated element cerium has been accurately measured for a large sample of disk stars from the infrared H band. The more r-process dominated element ytterbium has only been measured in a small subset of stars so far.
Aims
.
In this study we aim to measure the ytterbium (Yb) abundance of local disk giants using the Yb II line at
λ
air
= 16 498 Å. We also compare the resulting abundance trend with cerium and europium abundances for the same stars to analyse the
s
- and
r
-process contributions.
Methods
.
We analyse 30 K giants with high-resolution H band spectra using spectral synthesis. The very same stars have already been analysed using high-resolution optical spectra via the same method, but it was not possible to determine the abundance of Yb from those spectra due to blending issues for stars with Fe/H > −1. In the present analysis, we utilise the stellar parameters determined from the optical analysis.
Results
.
We determined the Yb abundances with an estimated uncertainty for Yb/Fe of 0.1 dex. By comparison, we found that the Yb/Fe trend closely follows the Eu/Fe trend and has clear s-process enrichment in identified
s
-rich stars. This comparison confirms both that the validity of the Yb abundances is ensured and that the theoretical prediction that the
s-/r
-process contribution to the origin of Yb of roughly 40/60 is supported.
Conclusions
.
These results show that, with a careful and detailed analysis of infrared spectra, reliable Yb abundances can be derived for a wider sample of cooler giants in the range −1.1 < Fe/H < 0.3. This is promising for further studies of the production of Yb and for the
r
-process channel, key for galactochemical evolution, in the infrared.
Context.
Stellar activity is currently challenging the detection of young planets via the radial velocity (RV) technique.
Aims.
We attempt to definitively discriminate the nature of the RV variations ...for the young active K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent results on the existence of a substellar companion.
Methods.
We compare VIS data with high precision RVs in the near-infrared (NIR) range by using the GIANO–B and IGRINS spectrographs. In addition, we present for the first time simultaneous VIS-NIR observations obtained with GIARPS (GIANO–B and HARPS–N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV amplitude does not change at different wavelengths, while stellar activity induces wavelength-dependent RV variations, which are significantly reduced in the NIR range with respect to the VIS.
Results.
The NIR radial velocity measurements from GIANO–B and IGRINS show an average amplitude of about one quarter with respect to previously published VIS data, as expected when the RV jitter is due to stellar activity. Coeval multi-band photometry surprisingly shows larger amplitudes in the NIR range, explainable with a mixture of cool and hot spots in the same active region.
Conclusions.
In this work, the claimed massive planet around BD+20 1790 is ruled out by our data. We exploited the crucial role of multi-wavelength spectroscopy when observing young active stars: thanks to facilities like GIARPS that provide simultaneous observations, this method can reach its maximum potential.
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