To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The search for life in the Universe is a fundamental problem of astrobiology and modern science. The current progress in the detection of terrestrial-type exoplanets has opened a new avenue in the characterization of exoplanetary atmospheres and in the search for biosignatures of life with the upcoming ground-based and space missions. To specify the conditions favourable for the origin, development and sustainment of life as we know it in other worlds, we need to understand the nature of global (astrospheric), and local (atmospheric and surface) environments of exoplanets in the habitable zones (HZs) around G-K-M dwarf stars including our young Sun. Global environment is formed by propagated disturbances from the planet-hosting stars in the form of stellar flares, coronal mass ejections, energetic particles and winds collectively known as astrospheric space weather. Its characterization will help in understanding how an exoplanetary ecosystem interacts with its host star, as well as in the specification of the physical, chemical and biochemical conditions that can create favourable and/or detrimental conditions for planetary climate and habitability along with evolution of planetary internal dynamics over geological timescales. A key linkage of (astro)physical, chemical and geological processes can only be understood in the framework of interdisciplinary studies with the incorporation of progress in heliophysics, astrophysics, planetary and Earth sciences. The assessment of the impacts of host stars on the climate and habitability of terrestrial (exo)planets will significantly expand the current definition of the HZ to the biogenic zone and provide new observational strategies for searching for signatures of life. The major goal of this paper is to describe and discuss the current status and recent progress in this interdisciplinary field in light of presentations and discussions during the NASA Nexus for Exoplanetary System Science funded workshop ‘Exoplanetary Space Weather, Climate and Habitability’ and to provide a new roadmap for the future development of the emerging field of exoplanetary science and astrobiology.
An X-ray diffraction (XRD) technique is employed to determine the presence or absence of crystalline phases in glass batch and to determine its homogeneity qualitatively and quantitatively.
Sample preparation problems are discussed, and promising techniques for sample preparation are presented. Qualitative batch homogeneity determination is accomplished by comparing the integrated intensity of a particular reflection of the reference sample to that of the unknown sample. Quantitative batch determination is accomplished by using the internal standard method. Three replicated data sets indicate that the standard deviation of kaolinite and colemanite are higher than those of quartz and calcite. However, the overall data from the quantitative analyses lie within an acceptable range of precision and accuracy.
There is absence knowledge about the effects of lactation trimester and parity on eating behavior, production and efficiency of dairy cows. Objective of this study was to identify and characterize in 340 dairy cows, the 20% high efficient (HE), 20% low efficient (LE) and 60% mid efficient (ME) cows according to their individual residual feed intake (RFI) values, within and between lactation trimesters and between 1st and 2nd parities. Efficiency effect within each lactation trimester, was exhibited in daily dry matter intake (DMI), eating rate and meal size, that were the highest in LE cows, moderate in the ME cows and lowest in the HE group. Daily eating time, meal frequency, yields of milk and energy-corrected milk (ECM) and BW were similar in the three efficiency groups within each trimester. The lower efficiency of the LE cows in each trimester attributes to their larger metabolic energy intake, heat production and energy losses. In subgroup of 52 multiparous cows examined along their 1st and 2nd trimesters, milk and ECM production, DMI, eating behavior and efficiency traits were similar with high Pearson’s correlation (r=0.78 to 0.89) between trimesters. In another subgroup of 42 multiparous cows measured at their 2nd and 3rd trimesters, milk and ECM yield, DMI and eating time were reduced (P<0.01) at the 3rd trimester, but eating rate, meal frequency and meal size remained similar with high Pearson’s correlation (r=0.74 to 0.88) between trimesters. In subgroup of 26 cows measured in 1st and 2nd parities, DMI, BW, milk and ECM yield, and ECM/DMI increased in the 2nd lactation, but eating behavior and RFI traits were similar in both parities. These findings encourage accurate prediction of DMI based on a model that includes eating behavior parameters, together with individual measurement of ECM production. This can be further used to identify HE cows in commercial herd, a step necessary for potential genetic selection program aimed to improve herd efficiency.
An internationally approved and globally used classification scheme for the diagnosis of CHD has long been sought. The International Paediatric and Congenital Cardiac Code (IPCCC), which was produced and has been maintained by the International Society for Nomenclature of Paediatric and Congenital Heart Disease (the International Nomenclature Society), is used widely, but has spawned many “short list” versions that differ in content depending on the user. Thus, efforts to have a uniform identification of patients with CHD using a single up-to-date and coordinated nomenclature system continue to be thwarted, even if a common nomenclature has been used as a basis for composing various “short lists”. In an attempt to solve this problem, the International Nomenclature Society has linked its efforts with those of the World Health Organization to obtain a globally accepted nomenclature tree for CHD within the 11th iteration of the International Classification of Diseases (ICD-11). The International Nomenclature Society has submitted a hierarchical nomenclature tree for CHD to the World Health Organization that is expected to serve increasingly as the “short list” for all communities interested in coding for congenital cardiology. This article reviews the history of the International Classification of Diseases and of the IPCCC, and outlines the process used in developing the ICD-11 congenital cardiac disease diagnostic list and the definitions for each term on the list. An overview of the content of the congenital heart anomaly section of the Foundation Component of ICD-11, published herein in its entirety, is also included. Future plans for the International Nomenclature Society include linking again with the World Health Organization to tackle procedural nomenclature as it relates to cardiac malformations. By doing so, the Society will continue its role in standardising nomenclature for CHD across the globe, thereby promoting research and better outcomes for fetuses, children, and adults with congenital heart anomalies.
We have previously shown that the minor alleles of vascular endothelial growth factor A (VEGFA) single-nucleotide polymorphism rs833069 and superoxide dismutase 2 (SOD2) single-nucleotide polymorphism rs2758331 are both associated with improved transplant-free survival after surgery for CHD in infants, but the underlying mechanisms are unknown. We hypothesised that one or both of these minor alleles are associated with better systemic ventricular function, resulting in improved survival.
This study is a follow-up analysis of 422 non-syndromic CHD patients who underwent neonatal cardiac surgery with cardiopulmonary bypass. Echocardiographic reports were reviewed. Systemic ventricular function was subjectively categorised as normal, or as mildly, moderately, or severely depressed. The change in function was calculated as the change from the preoperative study to the last available study. Stepwise linear regression, adjusting for covariates, was performed for the outcome of change in ventricular function. Model comparison was performed using Akaike’s information criterion. Only variables that improved the model prediction of change in systemic ventricular function were retained in the final model.
Genetic and echocardiographic data were available for 335/422 subjects (79%). Of them, 33 (9.9%) developed worse systemic ventricular function during a mean follow-up period of 13.5 years. After covariate adjustment, the presence of the VEGFA minor allele was associated with preserved ventricular function (p=0.011).
These data support the hypothesis that the mechanism by which the VEGFA single-nucleotide polymorphism rs833069 minor allele improves survival may be the preservation of ventricular function. Further studies are needed to validate this genotype–phenotype association and to determine whether this mechanism is related to increased vascular endothelial growth factor production.
A segment of the Milky Way in Norma, from ℓ = 327° to 335°, |b|≦ 1°, has been studied as part of the Columbia CO survey of the fourth galactic quadrant. Description of the entire survey is given by Cohen elsewhere in this volume.
The observational status of superluminal radio sources is reviewed, and the results for one well-studied source (3C 345) are discussed in detail. We discuss the relativistic-beam model of superluminal sources, and concentrate on one aspect, namely the geometric constraints provided by combined X-ray and proper-motion measurements.
One view of major Solar Energetic Particle (SEP) events is that these (proton-dominated) fluxes are accelerated in heliospheric shock sources created by Interplanetary Coronal Mass Ejections (ICMEs), and then travel mainly along interplanetary magnetic field lines connecting the shock(s) to the observer(s). This places a particular emphasis on the role of the heliospheric conditions during the event, requiring a realistic description of the latter to interpret and/or model SEP events. The well-known ENLIL heliospheric simulation with cone model generated ICME shocks is used together with the SEPMOD particle event modeling scheme to demonstrate the value of applying these concepts at multiple inner heliosphere sites.
Public health interest in norovirus (NoV) has increased in recent years following improved diagnostics, global burden estimates and the development of NoV vaccine candidates. This study aimed to describe the detection rate, clinical characteristics and environmental features associated with NoV detection in hospitalized children <5 years with diarrhoea in South Africa (SA). Between 2009 and 2013, prospective diarrhoeal surveillance was conducted at four sites in SA. Stool specimens were collected and screened for NoVs and other enteric pathogens using molecular and serological assays. Epidemiological and clinical data were compared in patients with or without detection of NoV. The study detected NoV in 15% (452/3103) of hospitalized children <5 years with diarrhoea with the majority of disease in children <2 years (92%; 417/452). NoV-positive children were more likely to present with diarrhoea and vomiting (odds ratio (OR) 1·3; 95% confidence interval (CI) 1·1–1·7; P = 0·011) with none-to-mild dehydration (adjusted OR 0·5; 95% CI 0·3–0·7) compared with NoV-negative children. Amongst children testing NoV positive, HIV-infected children were more likely to have prolonged hospitalization and increased mortality compared with HIV-uninfected children. Continued surveillance will be important to consider the epidemic trends and estimate the burden and risk of NoV infection in SA.
Recent spectropolarimetric surveys of bright, hot stars have found that ~10% of OB-type stars contain strong (mostly dipolar) surface magnetic fields (~kG). The prominent paradigm describing the interaction between the stellar winds and the surface magnetic field is the magnetically confined wind shock (MCWS) model. In this model, the stellar wind plasma is forced to move along the closed field loops of the magnetic field, colliding at the magnetic equator, and creating a shock. As the shocked material cools radiatively it will emit X-rays. Therefore, X-ray spectroscopy is a key tool in detecting and characterizing the hot wind material confined by the magnetic fields of these stars. Some B-type stars are found to have very short rotational periods. The effects of the rapid rotation on the X-ray production within the magnetosphere have yet to be explored in detail. The added centrifugal force due to rapid rotation is predicted to cause faster wind outflows along the field lines, leading to higher shock temperatures and harder X-rays. However, this is not observed in all rapidly rotating magnetic B-type stars. In order to address this from a theoretical point of view, we use the X-ray Analytical Dynamical Magnetosphere (XADM) model, originally developed for slow rotators, with an implementation of new rapid rotational physics. Using X-ray spectroscopy from ESA’s XMM-Newton space telescope, we observed 5 rapidly rotating B-types stars to add to the previous list of observations. Comparing the observed X-ray luminosity and hardness ratio to that predicted by the XADM allows us to determine the role the added centrifugal force plays in the magnetospheric X-ray emission of these stars.
Large magnetometric surveys have contributed to the detection of an increasing number of magnetic massive stars, and to the recognition of a population of magnetic massive stellar objects with distinct properties. Among these, NGC 1624-2 possesses the largest magnetic field of any O-type star; such a field confines the stellar wind into a circumstellar magnetosphere, which can be probed using observations at different wavelength regimes. Recent optical and X-ray observations suggest that NGC 1624-2’s magnetosphere is much larger than that of any other magnetic O star. By modeling the variations of UV resonance lines, we can constrain its velocity structure. Furthermore, recent spectropolarimetric observations raise the possibility of a more complex field topology than previously expected. Putting all of these multi-wavelength constraints together will allow us to paint a consistent picture of NGC 1624-2 and its surprising behavior, giving us valuable insight into the very nature of massive star magnetospheres.
Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease involving multiple organs, including the central nervous system. Evidence of immune dysfunction exists also in schizophrenia, a psychiatric illness involving chronic or recurrent psychosis. The aim of our study was to investigate if there is an epidemiological association between SLE and schizophrenia.
A cross-sectional study was conducted comparing patients with SLE with age and gender-matched controls regarding the proportion of patients with comorbid schizophrenia. χ2- and t-tests were used for univariate analysis, and interaction of schizophrenia with SLE across strata of covariates was checked. A logistic regression model was used for multivariate analysis. The study was performed utilising the medical database of Clalit Health Services in Israel.
The study included 5018 patients with SLE and 25 090 controls. SLE patients had a female predominance, and a higher proportion of smoking compared with age and sex-matched controls. In multivariate analysis, SLE was found to be independently associated with schizophrenia while controlling for age, gender, socioeconomic status (SES) and smoking (OR 1.33, p = 0.042).
We found a positive association between SLE and schizophrenia across patients of different age, gender and SES. This association can contribute to understanding the pathophysiology of the two disorders and may also have clinical implications for earlier as well as better diagnosis and treatment.
We report on version 1.0 of the Edinburgh/AAO/Strasbourg catalogue of new and possible Planetary Nebulae (PN) distributed via cdrom at this meeting. We provide accurate positions, designations, images and other descriptive parameters for the PN. In future releases this will be supplemented by inclusion of spectra and related material such as line ratios, velocities etc.
The 900+ PN have been discovered solely from visual scrutiny of narrow-band exposures taken for the AAO/UKST H-alpha survey of the Southern Galactic Plane. Most have classic PN-type morphologies (i.e. bi-polar, rings, shells or ovals). SuperCOSMOS data will soon supersede our visual scanning but it proved an effective preliminary technique to identify candidate PN on the basis of morphology, isolation and identification as an H-alpha nebulosity. We already have confirmatory spectroscopy for ~ 700 objects. Much of our new sample are of very low surface brightness, with no obvious central star, and so have remained undetected in previous surveys. They are revealed here due to the excellent depth, resolution, coverage and uniformity of the H-alpha survey. Many PN are also well extended. The average angular size is 51″ with the median of 27″ but examples extend to several arcminutes. This may indicate many are in a highly evolved state where the central star has faded from easy optical detection and the nebula itself is dissipating into the ambient ISM. Large numbers of candidate PN have also been found in the Galactic Bulge region, most of which have been confirmed via UKST FLAIR/6dF MOS spectroscopy (Parker et al, in preparation and these proceedings).
By version 2.0 (release in 2002) we will have doubled the number of Galactic PN accrued from all sources over the last 75 years. This new catalogue should have a profound impact on many aspects of PN research.
We report on an unprecedented source of Planetary Nebulae (PN) discovered from AAO/UKST Hα survey images of the Southern Galactic Plane. A pristine region of PN discovery space is being sampled due to the excellent depth, coverage, resolution and uniformity of the Hα survey. Large numbers of new PN are being found (~1000 so far). They are typically more evolved, obscurred and of lower surface brightness than in most other surveys. The doubling of known PN should have a significant impact on many aspects of PN research.
In rapidly rotating stars with a purely radially driven stellar wind, conservation of wind angular momentum can lead to formation of an equatorial Wind Compressed Disk (WCD). However, for a line-driven stellar wind, recent 2D hydrodynamical simulations based on a localized, Sobolev treatment of the line-force indicate that nonradial components of the line-force can effectively inhibit formation of such a WCD. This presentation will describe current efforts to extend such 2D simulations to a nonlocal, smooth-source-function treatment of the line-force that can incorporate the intrinsically strong instability of line-driving to formation of small-scale, clumped structure. Key questions are how such small-scale clumped structure affects the nonradial line-force components that arise from large-scale velocity-gradient asymmetries, and in particular whether such nonradial forces can still inhibit WCD formation in a clumped flow. The results have important implications for the viability of the WCD mechanism as a paradigm for disk formation in Be stars.
There are striking global inequities in our knowledge of the incidence, aetiology, and outcome of psychotic disorders. For example, only around 10% of research on incidence of psychotic disorders originates in low- and middle-income countries. We established INTREPID I to develop, implement, and evaluate, in sites in India (Chengalpet), Nigeria (Ibadan), and Trinidad (Tunapuna-Piarco), methods for identifying and recruiting untreated cases of psychosis, as a basis for investigating incidence and, subsequently, risk factors, phenomenology, and outcome. In this paper, we compare case characteristics and incidence rates across the sites.
In each site, to identify untreated cases of psychoses in defined catchment areas, we established case detection systems comprising mental health services, traditional and spiritual healers, and key informants.
Rates of all untreated psychoses were 45.9 (per 1 00 000 person-years) in Chengalpet, 31.2 in Ibadan, and 36.9 in Tunapuna-Piarco. Duration of psychosis prior to detection was substantially longer in Chengalpet (median 232 weeks) than in Ibadan (median 13 weeks) and Tunapuna-Piarco (median 38 weeks). When analyses were restricted to cases with a short duration (i.e. onset within preceding 2 years) only, rates were 15.5 in Chengalpet, 29.1 in Ibadan, and 26.5 in Tunapuna-Piarco. Further, there was evidence of age and sex differences across sites, with an older average age of onset in Chengalpet and higher rates among women in Ibadan.
Our findings suggest there may be differences in rates of psychoses and in the clinical and demographic profiles of cases across economically and socially distinct settings.
Major depressive disorder (MDD) is a common and disabling condition with well-established heritability and environmental risk factors. Gene–environment interaction studies in MDD have typically investigated candidate genes, though the disorder is known to be highly polygenic. This study aims to test for interaction between polygenic risk and stressful life events (SLEs) or childhood trauma (CT) in the aetiology of MDD.
The RADIANT UK sample consists of 1605 MDD cases and 1064 controls with SLE data, and a subset of 240 cases and 272 controls with CT data. Polygenic risk scores (PRS) were constructed using results from a mega-analysis on MDD by the Psychiatric Genomics Consortium. PRS and environmental factors were tested for association with case/control status and for interaction between them.
PRS significantly predicted depression, explaining 1.1% of variance in phenotype (p = 1.9 × 10−6). SLEs and CT were also associated with MDD status (p = 2.19 × 10−4 and p = 5.12 × 10−20, respectively). No interactions were found between PRS and SLEs. Significant PRSxCT interactions were found (p = 0.002), but showed an inverse association with MDD status, as cases who experienced more severe CT tended to have a lower PRS than other cases or controls. This relationship between PRS and CT was not observed in independent replication samples.
CT is a strong risk factor for MDD but may have greater effect in individuals with lower genetic liability for the disorder. Including environmental risk along with genetics is important in studying the aetiology of MDD and PRS provide a useful approach to investigating gene–environment interactions in complex traits.
Figure 1 shows hybrid maps of the core of 3C 273B at five epochs, made with arrays of 4 or 5 VLBI antennas. The maps span a period of 3.5 years. They all show a bright eastern peak and a lower-brightness extension to the west. There is a local maximum in the western extension between 6 and 8 milliarcsec from the main peak. This “blob” moves steadily further away from the main peak along a roughly straight line in PA −116° ± 2°. Compare this with the position angle of the 25-arcsec optical jet, −137°. The maps show a slight curvature to the south with increasing separation from the main peak. Lower-resolution VLBI maps at lower frequencies show that this curvature continues at greater separations, suggesting a smooth connection between the milli-arcsecond position angle and the position angle of the optical jet. In our latest map (1981.09) the blob is no longer detectable with the limited dynamic range of the VLBI network (about 20:1).