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.
New angular diameter determinations for the bright southern F8 supergiant δ CMa enable the bolometric emergent flux and effective temperature of the star to be determined with improved accuracy. The spectral flux distribution and bolometric flux have been determined from published photometry and spectrophotometry and combined with the angular diameter to derive the bolometric emergent flux ℱ = (6.50 ± 0.24) × 107 Wm−2 and the effective temperature Teff = 5818 ± 53 K. The new value for the effective temperature is compared with previous interferometric and infrared flux method determinations. The accuracy of the effective temperature is now limited by the uncertainty in the bolometric flux rather than by the uncertainty in the angular diameter.
A new beam-combination and detection system has been installed in the Sydney University Stellar Interferometer working at the red end of the visual spectrum (λλ 500–950 nm) to complement the existing blue-sensitive system (λλ 430–520 nm) and to provide an increase in sensitivity. Dichroic beam-splitters have been introduced to allow simultaneous observations with both spectral systems, albeit with some restriction on the spectral range of the longer wavelength system (λλ 550–760 nm). The blue system has been upgraded to allow remote selection of wavelength and spectral bandpass, and to enable simultaneous operation with the red system with the latter providing fringe-envelope tracking. The new system and upgrades are described and examples of commissioning tests presented. As an illustration of the improvement in performance the measurement of the angular diameter of the southern F supergiant δ CMa is described and compared with previous determinations.
The Sydney University Stellar Interferometer (SUSI) has been used to make a new determination of the angular diameter of Sirius A. The observations were made at an effective wavelength of 694.1 nm and the new value for the limb-darkened angular diameter is 6.048 ± 0.040 mas (± 0.66%). This new result is compared with previous measurements and is found to be in excellent agreement with a conventionally calibrated measurement made with the European Southern Observatory's Very Large Telescope Interferometer (VLTI) at 2.176 μm (but not with a second globally calibrated VLTI measurement). A weighted mean of the SUSI and first VLTI results gives the limb-darkened angular diameter of Sirius A as 6.041 ± 0.017 mas (± 0.28%). Combination with the Hipparcos parallax gives the radius equal to 1.713 ± 0.009 R⊙. The bolometric flux has been determined from published photometry and spectrophotometry and, combined with the angular diameter, yields the emergent flux at the stellar surface equal to (5.32 ± 0.14) × 108 W m−2 and the effective temperature equal to 9845 ± 64 K. The luminosity is 24.7 ± 0.7 L⊙.
Objective: Several studies have provided prevalence estimates of posttraumatic stress disorder (PTSD) related to the September 11, 2001 (9/11) attacks in broadly affected populations, although without sufficiently addressing qualifying exposures required for assessing PTSD and estimating its prevalence. A premise that people throughout the New York City area were exposed to the attacks on the World Trade Center (WTC) towers and are thus at risk for developing PTSD has important implications for both prevalence estimates and service provision. This premise has not, however, been tested with respect to DSM-IV-TR criteria for PTSD. This study examined associations between geographic distance from the 9/11 attacks on the WTC and reported 9/11 trauma exposures, and the role of specific trauma exposures in the development of PTSD.
Methods: Approximately 3 years after the attacks, 379 surviving employees (102 with direct exposures, including 65 in the towers, and 277 with varied exposures) recruited from 8 affected organizations were interviewed using the Diagnostic Interview Schedule/Disaster Supplement and reassessed at 6 years. The estimated closest geographic distance from the WTC towers during the attacks and specific disaster exposures were compared with the development of 9/11–related PTSD as defined by the Diagnostic and Statistical Manual, Fourth Edition, Text Revision.
Results: The direct exposure zone was largely concentrated within a radius of 0.1 mi and completely contained within 0.75 mi of the towers. PTSD symptom criteria at any time after the disaster were met by 35% of people directly exposed to danger, 20% of those exposed only through witnessed experiences, and 35% of those exposed only through a close associate’s direct exposure. Outside these exposure groups, few possible sources of exposure were evident among the few who were symptomatic, most of whom had preexisting psychiatric illness.
Conclusions: Exposures deserve careful consideration among widely affected populations after large terrorist attacks when conducting clinical assessments, estimating the magnitude of population PTSD burdens, and projecting needs for specific mental health interventions.
(Disaster Med Public Health Preparedness. 2011;5:S205-S213)
Two upcoming large scale surveys, the ESA Gaia and LSST projects, will bring a new era in astronomy. The number of binary systems that will be observed and detected by these projects is enormous, estimations range from millions for Gaia to several tens of millions for LSST. We review some tools that should be developed and also what can be gained from these missions on the subject of binaries and exoplanets from the astrometry, photometry, radial velocity and their alert systems.
To compare an existing crisis resolution service with a new crisis resolution team (CRT) in Wales. The impact of the new team was measured by changes in bed days and admissions. A random sample of patients from each service was assessed for service satisfaction, social functioning and quality of life after first presentation.
The total number of bed days was reduced following the introduction of the new CRT (27.3%). The frequency and duration of compulsory admissions increased by 31% in the CRT between the first and second years and by 7% in the control service, offset by a greater reduction in informal admissions in the CRT (23.5%) compared with the control group (13.3%); overall bed usage was unchanged. Service satisfaction, social functioning and quality of life showed no important differences between the services.
Crisis resolution teams may reduce informal admissions in the short term but at the cost of more compulsory admissions later.
Lithium has long been known to be a good tracer of non-standard mixing processes occurring in stellar interiors. Here we present the results of a large survey aimed at determining the surface Li abundance in a sample of about 800 giant (RGB and AGB) stars with accurate Hipparcos parallaxes. We compare the observed Li behaviour with that predicted by stellar models including rotation and thermohaline mixing.
Distribution, size composition and behaviour of Euphausia superba were investigated in the northwestern Weddell Sea (59–63°S, 45–52°W) in October-November 1988 using RMT trawling, SCUBA diving and visual examination of the ice undersurface using a remotely-operated vehicle (ROV). Amounts of krill washed onto the ice during ice-breaking along transects were noted. Juvenile and sub-adult krill were found, often in high numbers, in association with seasonal pack-ice, from the outer marginal ice zone to at least 200 nautical miles [3 50 km] into the closed pack-ice zone. Krill caught with the RMT or observed within or close to the ice usually had full guts. They were frequently seen feeding on ice algae, and seemed to concentrate in pressure zones, melting ice and infiltration layers, ie where ice provided both confining crevices and rich algal growth. During twilight numbers of krill increased in open water close to the ice, though ROV observations at night revealed even greater numbers remaining in ice cavities. Direct observations from deck, by divers and by ROV, confirmed that most of the krill population in the uppermost water layer was confined to ice habitats, though in three out of 20 RMT catches krill reached densities of 0.1 nr3 ie normal summer values. ‘Miniswarms’ forming in early November may indicate seasonal transition of at least part of the krill population from winter ice habitat and grazing on ice-algae, to summer pelagic life and filter-feeding on phytoplankton.
Personality disorder (PD) in psychosis is poorly studied. As PD can affect outcome in mental disorders, it is important to understand its prevalence in order to plan services, understand prognosis more fully and maximize management options.
Literature searching revealed 3972 potential papers. Twenty papers including 6345 patients were included in the final analysis. There was great variation in prevalence and multilevel modelling was used to identify possible reasons for this heterogeneity.
The prevalence of PD varied from 4.5% to 100%. Multilevel analysis suggested country of study, study type, the instruments used to diagnose PD and patient care correlated with the prevalence data explaining the study level heterogeneity, with 34.2, 33.4, 17.0 and 4.5% by each variable respectively. Personality studies in Canada and Sweden reported lower PD prevalence, whereas in Spain it was higher than the multinational study. Compared with randomized controlled trials, case-control studies reported lower prevalence [odds ratio (OR)=0.35, 95% confidence interval (CI) 0.15–0.79] and observational studies higher prevalence (OR 70.5, 95% CI 8.5–583). Primary-care patients were less likely to be diagnosed (OR 0.02, 95% CI 0–0.19) than hospital patients, and out-patients had higher prevalence (OR 12.5, 95% CI 1.77–88.6).
The reported prevalence of PD in schizophrenia varies significantly. Statistical modelling suggests care, country, study type and diagnostic tools for PD all bias prevalence rates. The number of papers reaching the inclusion criteria, the relative paucity of information and the difficulties in developing an accurate statistical model limited interpretation from the study.
The potential of using the entomopathogenic nematode Steinernema feltiae to control the sweetpotato whitefly Bemisia tabaci (Gennadius) has been established in previous laboratory studies. However, laboratory studies can overestimate the level of control achieved by biocontrol agents in the glasshouse. Glasshouse trials are therefore required to confirm laboratory results before full-scale commercial development is considered. Under both controlled laboratory and glasshouse conditions high mortality of second instar B. tabaci (>90% and >80%, respectively) was recorded after application of S. feltiae. The efficacy of the biocontrol agent at various application rates was also investigated, where halving the rate of S. feltiae application caused no significant reduction in B. tabaci mortality on tomato foliage. Steinernema feltiae has shown much potential for incorporation into integrated pest management strategies for the control of B. tabaci.
The carbon isotopic ratio, 12C/13C, is a tracer of the mixing events during the evolution along the giant branch, due to the conversion of 12C into 13C (and 14N) via the CN cycle. A decrease of this ratio from 90, the solar value, to 20–25, is expected due to the first dredge-up. However, ratios down to 3–4, the CN cycle equilibrium value, have been observed in giants of the field, of globular and of open clusters. Observations seem to indicate a non-standard mixing in the RGB, probably beginning in the luminosity bump, when the outward moving hydrogen burning shell crosses the molecular weight barrier left by the convective layer in its maximum extent. We are currently analyzing a sample of 24 giants in 8 open clusters for which we determined 12C/13C from high resolution, high signal to noise spectra using spectrum synthesis. In this work we discuss the general characteristics of our results in comparison to previous analyses of giants in open clusters available in the literature.
The international Project “Lithium in magnetic CP stars” has been put into operation using telescopes of the Crimean Astrophysical Observatory (2.6-m reflector ZTSH), European Southern Observatory (1.4-m CAT, 1.52-m with FEROS), Mount Stromlo Observatory (74-inch), Nordic Optical Telescope Scientific Association (2.4-m with SOFIN), Special Astrophysical Observatory of the Russian Academy of Sciences (6-m BTA). Here we present an historical report of the different scientific results of this project since its beginning in 1996.
Preliminary abundances of lithium and a few other elements have been obtained
for 31 field Am stars with good Hipparcos parallaxes, as well as for
36 normal A and F stars. Radial and projected rotational velocities
were determined as well. We examine the Li abundance as a function of
the stellar parameters: for normal stars, it is clearly bimodal for
Teff< 7500 K, while Am-Fm stars are all somewhat Li-deficient
in this range. The most Li-deficient stars – either Am or normal – tend
to be at least slightly evolved, but the reverse is not true.
Making use of detached eclipsing binaries with B-type components discovered by the OGLE and MACHO teams in the SMC and in the LMC, we give the value of the fractional radius above which circularization occurs. This critical radius is around 0.24 to 0.26, regardless of the mass, surface gravity or metallicity, and is consistent with that found by Giuricin et al. (1984) for galactic binaries. These empirical facts are shown to be consistent with Zahn’s (1975) theory of tidal dissipation. This work confirms and extends that of North & Zahn (2003), thanks to a sample of 448 binaries taken from the recent OGLE catalogue of 2580 eclipsing binaries in the LMC (Wyrzykowski et al. 2003) and a more homogeneous interpretation of the lightcurves of the 148 SMC binaries.