842 research outputs found
Strain identity of the ectomycorrhizal fungus Laccaria bicolor is more important than richness in regulating plant and fungal performance under nutrient rich conditions
This work was funded by the Natural Environment Research Council (NE/I014527/1).Peer reviewedPublisher PD
Environment Behavior Models for Scenario Generation and Testing Automation
In Proceedings of the First International Workshop on Advances in Model-Based Software Testing (A-MOST'05), the 27th International Conference on Software Engineering ICSE’05, May 15-16, 2005, St. Louis, USAThis paper suggests an approach to automatic scenario generation
from environment models for testing of real-time reactive
systems. The behavior of the system is defined as a set of events
(event trace) with two basic relations: precedence and inclusion.
The attributed event grammar (AEG) specifies possible event
traces and provides a uniform approach for automatically
generating, executing, and analyzing test cases. The environment
model includes a description of hazardous states in which the
system may arrive and makes it possible to gather statistics for
system safety assessment. The approach is supported by a
generator that creates test cases from the AEG models. We
demonstrate the approach with case studies of prototypes for the
safety-critical computer-assisted resuscitation algorithm (CARA)
software for a casualty intravenous fluid infusion pump and the
Paderborn Shuttle System
The Metallicity of High Redshift Galaxies: The Abundance of Zinc in 34 Damped Lyman Alpha Systems from z = 0.7 to 3.4
We report new observations of ZnII and CrII absorption lines in 10 damped
\lya systems (DLAs), mostly at redshift z_{abs} \simgt 2.5 . By combining
these results with those from our earlier survey (Pettini et al. 1994) and
other recent data, we construct a sample of 34 measurements (or upper limits)
of the Zn abundance relative to hydrogen [Zn/H]; the sample includes more than
one third of the total number of DLAs known.
The plot of the abundance of Zn as a function of redshift reinforces the two
main findings of our previous study. (1) Damped \lya systems are mostly
metal-poor, at all redshifts sampled; the column density weighted mean for the
whole data set is [Zn/H] (on a logarithmic scale), or
approximately 1/13 of solar. (2) There is a large spread, by up to two orders
of magnitude, in the metallicities we measure at essentially the same
redshifts. We propose that damped \lya systems are drawn from a varied
population of galaxies of different morphological types and at different stages
of chemical evolution, supporting the idea of a protracted epoch of galaxy
formation.
At redshifts z \simgt 2 the typical metallicity of the damped \lya systems
is in agreement with expectations based on the consumption of HI gas implied by
the recent measurements of by Storrie-Lombardi et al. (1996a),
and with the metal ejection rates in the universe at these epochs deduced by
Madau (1996) from the ultraviolet luminosities of high redshift galaxies
revealed by deep imaging surveys. There are indications in our data for an
increase in the mean metallicity of the damped \lya systems from to
, consistent with the rise in the comoving star formation rate
indicated by the relative numbers of and drop-outs in the Hubble Deep
Field. Although such comparisons are still tentative, it appears that these
different avenues for exploring the early evolution of galaxies give a broadly
consistent picture.Comment: 51 pages, LaTeX, 9 Postscript Figures. Accepted for publication in
the Astrophysical Journa
Review: Towards the agroecological management of ruminants, pigs and poultry through the development of sustainable breeding programmes. II. Breeding strategies
Agroecology uses ecological processes and local resources rather than chemical inputs to develop productive and resilient livestock and crop production systems. In this context, breeding innovations are necessary to obtain animals that are both productive and adapted to a broad range of local contexts and diversity of systems. Breeding strategies to promote agroecological systems are similar for different animal species. However, current practices differ regarding the breeding of ruminants, pigs and poultry. Ruminant breeding is still an open system where farmers continue to choose their own breeds and strategies. Conversely, pig and poultry breeding is more or less the exclusive domain of international breeding companies which supply farmers with hybrid animals. Innovations in breeding strategies must therefore be adapted to the different species. In developed countries, reorienting current breeding programmes seems to be more effective than developing programmes dedicated to agroecological systems that will struggle to be really effective because of the small size of the populations currently concerned by such systems. Particular attention needs to be paid to determining the respective usefulness of cross-breeding v. straight breeding strategies of well-adapted local breeds. While cross-breeding may offer some immediate benefits in terms of improving certain traits that enable the animals to adapt well to local environmental conditions, it may be difficult to sustain these benefits in the longer term and could also induce an important loss of genetic diversity if the initial pure-bred populations are no longer produced. As well as supporting the value of within-breed diversity, we must preserve between-breed diversity in order to maintain numerous options for adaptation to a variety of production environments and contexts. This may involve specific public policies to maintain and characterize local breeds (in terms of both phenotypes and genotypes), which could be used more effectively if they benefited from the scientific and technical resources currently available for more common breeds. Last but not least, public policies need to enable improved information concerning the genetic resources and breeding tools available for the agroecological management of livestock production systems, and facilitate its assimilation by farmers and farm technicians
An Infrared Search for Star-Forming Galaxies at z > 2
We report the cumulative results of an on-going near-infrared search for
redshifted H-alpha emission from normal galaxies at z>2. An infrared search
reduces the bias due to reddening. Using narrow-band imaging with the Near
Infrared Camera on the Keck I 10-m telescope, a survey area of almost 12 square
arcminutes has been covered. Target regions were selected by matching the
redshifts of QSO emission and metal-line absorptions to our available filters.
The survey depth is 7E-17 ergs/cm^2/s (3sigma) in H-alpha and K-prime ~22.
Eleven H-alpha-emitters, plus two Seyfert I objects, have been discovered. The
high density of galaxy detections, corresponding to a co-moving volume density
of 0.0135/Mpc^3, makes it unlikely that all of the H-alpha flux in these
objects is the result of active nuclei. There is a strong suggestion of
clustering in the environments of metal-line absorbers. Each candidate galaxy
lies typically within a projected distance of 250kpc of the QSO line of sight
and is resolved but compact. The average Star Formation Rate inferred for the
galaxies from the H-alpha flux is 50 Msun/yr, significantly higher than current
day star-forming galaxies, but consistent with other estimates for galaxies at
high redshift.Comment: 39 pages including 17 figures, accepted for publication in Ap
Receipt of Guideline-Concordant Care Among Older Women With Stage I-III Breast Cancer: A Population-Based Study
Background: This study examined receipt of guideline-concordant care (GCC) according to evidence-based treatment guidelines and quality measures and specific types of treatment among older women with breast cancer. Patients and Methods: A total of 142,433 patients aged ≥66 years diagnosed with stage I–III breast cancer between 2007 and 2011 were identified in the SEER-Medicare linked database. Algorithms considering cancer characteristics and the appropriate course of care as per guidelines versus actual care received determined receipt of GCC. Multivariable logistic regression estimated the likelihood of GCC and specific types of treatment for women aged ≥75 versus 66 to 74 years. Results: Overall, 39.7% of patients received GCC. Patients diagnosed at stage II or III, with certain preexisting conditions, and of nonwhite race were less likely to receive GCC. Patients with hormone-negative tumors, higher grade tumors, and greater access to oncology care resources were more likely to receive GCC. Patients aged ≥75 years were approximately 40% less likely to receive GCC or adjuvant endocrine therapy, 78% less likely to have any surgery, 61% less likely to have chemotherapy, and about half as likely to have radiation therapy than those aged 66 to 74 years. Conclusions: Fewer than half of older women with breast cancer received GCC, with the lowest rates observed among the oldest age groups, racial/ethnic minorities, and women with later-stage cancers. However, patients with more aggressive tumor characteristics and greater access to oncology resources were more likely to receive GCC. Considering that older women have the highest incidence of breast cancer and that many are diagnosed at stages requiring more aggressive treatment, efforts to increase rates of earlier stage diagnosis and the development of less toxic treatments could help improve GCC and survival while preserving quality of life
Effect of semolina pudding prepared from starch branching enzyme IIa and b mutant wheat on glycaemic response in vitro and in vivo: a randomised controlled pilot study
Refined starchy foods are usually rapidly digested, leading to poor glycaemic control, but not all starchy foods are the same. Complex carbohydrates like resistant starch (RS) have been shown to reduce the metabolic risk factors for chronic diseases such as hyperglycaemia and overweight. The aim of the project was to develop a semolina-based food made from a starch branching enzyme II (sbeIIa/b-AB) durum wheat mutant with a high RS content and to measure its glycaemic index using a double-blind randomised pilot study. We report here the amylose, RS and non-starch polysaccharide concentration of raw sbeIIa/b-AB and wild-type control (WT) semolina. We measured RS after cooking to identify a model food for in vivo testing. Retrograded sbeIIa/b-AB semolina showed a higher RS concentration than the WT control (RS = 4.87 ± 0.6 g per 100 g, 0.77 ± 0.34 g per 100 g starch DWB, respectively), so pudding was selected as the test food. Ten healthy participants consumed ∼50 g of total starch from WT and sbeIIa/b-AB pudding and a standard glucose drink. Capillary blood glucose concentrations were measured in the fasting and postprandial state (2 h): incremental area-under-the-curve (iAUC) and GI were calculated. We found no evidence of difference in GI between sbeIIa/b-AB pudding and the WT control, but the starch digestibility was significantly lower in sbeIIa/b-AB pudding compared to the WT control in vitro (C90 = 33.29% and 47.38%, respectively). Based on these results, novel sbeIIa/b-AB wheat foods will be used in future in vivo studies to test the effect of different RS concentrations and different food matrices on glycaemia
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