5,586 research outputs found
XMM-Newton observations of the Seyfert 1 AGN H0557-385
We present XMM-Newton observations of the Seyfert 1 AGN H0557-385. We have
conducted a study into the warm absorber present in this source, and using
high-resolution RGS data we find that the absorption can be characterised by
two phases: a phase with log ionisation parameter xi of 0.50 (where xi is in
units of ergs cm/s) and a column of 0.2e21 cm^-2, and a phase with log xi of
1.62 and a column of 1.3e22 cm^-2. An iron K alpha line is detected. Neutral
absorption is also present in the source, and we discuss possible origins for
this. On the assumption that the ionised absorbers originate as an outflow from
the inner edge of the torus, we use a new method for finding the volume filling
factor. Both phases of H0557-385 have small volume filling factors (< 1%). We
also derive the volume filling factors for a sample of 23 AGN using this
assumption and for the absorbers with log xi > 0.7 we find reasonable agreement
with the filling factors obtained through the alternative method of equating
the momentum flow of the absorbers to the momentum loss of the radiation field.
By comparing the filling factors obtained by the two methods, we infer that
some absorbers with log xi < 0.7 occur at significantly larger distances from
the nucleus than the inner edge of the torus.Comment: Accepted for publication in MNRA
Potential and pitfalls in the genetic diagnosis of kidney diseases
Next-generation sequencing has dramatically decreased the cost of gene sequencing, facilitating the simultaneous analysis of multiple genes at the same time; obtaining a genetic result for an individual patient has become much easier. The article by Ars and Torra in this issue of the Clinical Kidney Journal provides examples of the ever-increasing ability to understand a given patient's disease on the molecular level, so that in some cases not only the causative variants in a disease gene are identified, but also potential modifiers in other genes. Yet, with increased sequencing, a large number of variants are discovered that are difficult to interpret. These so-called 'variants of uncertain significance' raise important questions: when and how can pathogenicity be clearly attributed? This is of critical importance, as there are potentially serious consequences attached: decisions about various forms of treatment and even about life and death, such as termination of pregnancy, may hinge on the answer to these questions. Geneticists, thus, need to use the utmost care in the interpretation of identified variants and clinicians must be aware of this problem. We here discuss the potential of genetics to facilitate personalized treatment, but also the pitfalls and how to deal with them
Development and Use of Color Standards for Egg Yolks
Abstract FOR SOME YEARS poultry scientists have been engaged in nutrition studies on the effects of various grains fed to laying birds. Some of these studies have been concerned with the effect of grain or combinations of grains in determining yolk color. The desired yolk color for home use varies with the geographical location and customs of the people, but in general a fairly light color is preferred. On the other hand users of yolks such as noodle manufacturers and cake bakers pay premium prices for dark colored yolk. It is therefore more profitable for the egg producer if he accurately maintains the yolk color within the desired range for his particular market. Since verbal color descriptions are ambiguous it is necessary to have standards for egg yolk colors in recording and communicating the results of poultry diet research. The only color chart available in Canada was one which had been
Multistability of free spontaneously-curved anisotropic strips
Multistable structures are objects with more than one stable conformation,
exemplified by the simple switch. Continuum versions are often elastic
composite plates or shells, such as the common measuring tape or the slap
bracelet, both of which exhibit two stable configurations: rolled and unrolled.
Here we consider the energy landscape of a general class of multistable
anisotropic strips with spontaneous Gaussian curvature. We show that while
strips with non-zero Gaussian curvature can be bistable, strips with positive
spontaneous curvature are always bistable, independent of the elastic moduli,
strips of spontaneous negative curvature are bistable only in the presence of
spontaneous twist and when certain conditions on the relative stiffness of the
strip in tension and shear are satisfied. Furthermore, anisotropic strips can
become tristable when their bending rigidity is small. Our study complements
and extends the theory of multistability in anisotropic shells and suggests new
design criteria for these structures.Comment: 20 pages, 10 figure
Assessing the effects of the first 2 years of industry-led badger culling in England on the incidence of bovine tuberculosis in cattle in 2013–2015
Culling badgers to control the transmission of bovine tuberculosis (TB) between this wildlife reservoir and cattle has been widely debated. Industry-led culling began in Somerset and Gloucestershire between August and November 2013 to reduce local badger populations. Industry-led culling is not designed to be a randomised and controlled trial of the impact of culling on cattle incidence. Nevertheless, it is important to monitor the effects of the culling and, taking the study limitations into account, perform a cautious evaluation of the impacts. A standardised method for selecting areas matched to culling areas in factors found to affect cattle TB risk has been developed to evaluate the impact of badger culling on cattle TB incidence. The association between cattle TB incidence and badger culling in the first two years has been assessed. Descriptive analyses without controlling for confounding showed no association between culling and TB incidence for Somerset, or for either of the buffer areas for the first two years since culling began. A weak association was observed in Gloucestershire for Year 1 only. Multivariable analysis adjusting for confounding factors showed that reductions in TB incidence were associated with culling in the first two years in both the Somerset and Gloucestershire intervention areas when compared to areas with no culling (IRR: 0.79, 95%CI: 0.72-0.87, p<0.001 and IRR: 0.42, 95%CI: 0.34-0.51, p<0.001 respectively). An increase in incidence was associated with culling in the 2 km buffer surrounding the Somerset intervention area (IRR: 1.38, 95%CI: 1.09-1.75, p=0.008), but not in Gloucestershire (IRR: 0.91, 95%CI: 0.77-1.07, p=0.243). As only two intervention areas with two years’ of data are available for analysis, and the biological cause-effect relationship behind the statistical associations is difficult to determine, it would be unwise to use these findings to develop generalisable inferences about the effectiveness of the policy at present
Microwave-assisted synthesis and electrochemical evaluation of VO2 (B) nanostructures
Understanding how intercalation materials change during electrochemical operation is paramount to optimizing their behaviour and function and in situ characterization methods allow us to observe these changes without sample destruction. Here we first report the improved intercalation properties of bronze phase vanadium dioxide VO2 (B) prepared by a microwave-assisted route which exhibits a larger electrochemical capacity (232 mAh g-1) compared with VO2 (B) prepared by a solvothermal route (197 mAh g-1). These electrochemical differences have also been followed using in situ X-ray absorption spectroscopy allowing us to follow oxidation state changes as they occur during battery operation
Fast Simulation of Facilitated Spin Models
We show how to apply the absorbing Markov chain Monte Carlo algorithm of
Novotny to simulate kinetically constrained models of glasses. We consider in
detail one-spin facilitated models, such as the East model and its
generalizations to arbitrary dimensions. We investigate how to maximise the
efficiency of the algorithms, and show that simulation times can be improved on
standard continuous time Monte Carlo by several orders of magnitude. We
illustrate the method with equilibrium and aging results. These include a study
of relaxation times in the East model for dimensions d=1 to d=13, which
provides further evidence that the hierarchical relaxation in this model is
present in all dimensions. We discuss how the method can be applied to other
kinetically constrained models.Comment: 8 pages, 4 figure
Historic Churches and Their Hygrothermal Environment: A Review of Criteria Related to Building Fabric, Artefacts, Artwork and Occupants
Regarded as important cultural heritage, historic churches have been utilised over hundreds of years for worship and community benefit. Simple on/off space heating systems are installed in many churches to increase human comfort. However, the conservation of the important historic artefacts and artwork contained within may not have been fully considered. This review attempts to appraise the standards in place for artefacts and artwork. A consensus of 15–25 °C and 40–65% relative humidity is established as safe from the standards reviewed. Consideration is given to the environment within the church to understand if such exacting conditions can be met. The review finds that the conservation and preservation of artefacts and buildings are aligned goals, although striving to meet specified target ranges for artefact types is not fully compatible with historic churches. The stability of the internal environment is clearly an important factor in conservation and benefits human comfort expectations. Churches may contain microclimates throughout the building, complicating the use of target ranges for artefacts, artwork and comfort. The findings of this study can assist historic churches in managing the change, alteration or installation of heating systems
Antibody responses to nasopharyngeal carriage of Streptococcus pneumoniae in adults: A longitudinal household study
Background. Natural immunity to Streptococcus pneumoniae is thought to be induced by exposure to S. pneumoniae or cross-reactive antigens. No longitudinal studies of carriage of and immune responses to S. pneumoniae have been conducted using sophisticated immunological laboratory techniques.Methods. We enrolled 121 families with young children into this study. Nasopharyngeal (NP) swabs were collected monthly for 10 months from all family members and were cultured in a standard fashion. Cultured S. pneumoniae isolates were serotyped. At the beginning (month 0) and end (month 10) of the study, venous blood was collected from family members 118 years old. Serotype-specific antipolysaccharide immunoglobulin G (IgG) and functional antibody and antibodies to pneumolysin, pneumococcal surface protein A (PspA), and pneumococcal surface antigen A (PsaA) were measured in paired serum samples.Results. Levels of anticapsular IgG increased significantly after carriage of serotypes 9V, 14, 18C, 19F, and 23F by an individual or family member. For serotype 14, a higher level of anticapsular IgG at the beginning of the study was associated with reduced odds of carriage (P = .0006). There was a small (similar to 20%) but significant increase in titers of antibodies to PsaA and pneumolysin but no change in titers of antibody to PspA.Conclusions. Adults respond to NP carriage by mounting anticapsular and weak antiprotein antibody responses, and naturally induced anticapsular IgG can prevent carriage
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