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Thin films containing periodic chemical or strain modulation (e.g. artificial superlattices or SL) are often characterized nondestructively by X-ray double-axis diffractometry. The satellite peaks from the modulated structure allow analysis of layer structure, elemental concentration and strain profile. This paper focuses on the effect of layer uniformity on the rocking curves of (001) GaAs/AlxGa1-xAsSL. Double-axis diffractometry for results from MBE samples with 800 Å SL periods and x=0.35 are compared for GaAs/AlGaAs layer thicknesses of 350/450, 400/400 and 450/350 Å. Symmetric (004) and asymmetric (315) diffraction planes are used to measure parallel and perpendicular misfit strains, layer periodicity and aluminum concentration. A modified kinematical scattering model, correcting for absorption and extinction, is used to calculate the satellite peak intensities and spacings. The relative thicknesses of GaAs and AlGaAs and the aluminum elemental concentration are optimized by matching with experimental results. The effect of nonuniform layer thickness on SL peak intensities is also investigated. The experimental results, the modified kinematical scattering calculations and dynamical theory agree closely for the 3-4 /zm thickness layers studied.
Studies have consistently shown that subthreshold depression is associated with an increased risk of developing major depression. However, no study has yet calculated a pooled estimate that quantifies the magnitude of this risk across multiple studies.
We conducted a systematic review to identify longitudinal cohort studies containing data on the association between subthreshold depression and future major depression. A baseline meta-analysis was conducted using the inverse variance heterogeneity method to calculate the incidence rate ratio (IRR) of major depression among people with subthreshold depression relative to non-depressed controls. Subgroup analyses were conducted to investigate whether IRR estimates differed between studies categorised by age group or sample type. Sensitivity analyses were also conducted to test the robustness of baseline results to several sources of study heterogeneity, such as the case definition for subthreshold depression.
Data from 16 studies (n = 67 318) revealed that people with subthreshold depression had an increased risk of developing major depression (IRR = 1.95, 95% confidence interval 1.28–2.97). Subgroup analyses estimated similar IRRs for different age groups (youth, adults and the elderly) and sample types (community-based and primary care). Sensitivity analyses demonstrated that baseline results were robust to different sources of study heterogeneity.
The results of this study support the scaling up of effective indicated prevention interventions for people with subthreshold depression, regardless of age group or setting.
The spectroscopic identification of the Extended Medium Sensitivity Survey (EMSS) sources now provides ∼350 X-ray selected QSOs and Seyfert galaxies (AGN in our working definition) and 30 BL Lac objects. Almost all of the AGN are spectroscopically similar to AGN found by other means but a few resemble normal galaxies so closely that they would not be identified as AGN easily by any other method.
The CIDA visual refractor of 65-cm aperture and focal length 10.5 m, has been used extensively for position determinations on photographic plates. The combination of Kodak D plates and a yellow filter permit an almost perfect adaptation to the focal curve of the telescope. It appeared of interest to test whether the telescope could be used for astrometric purposes with a CCD detector. As is well known, the spectral sensitivity of these detectors extends well into the infrared where the images formed by the telescope optics will be far out of focus. The blue spectral region where this would also be the case can easily be cut off by a yellow filter. There are no filters which would produce a similarly sharp cut-off towards the red region. On the other hand, given the small field covered by a CCD, the displacement of the red out-of-focus image with respect to the center of the visual image might be negligible. Recently obtained accurate positions in the area of the Perseus Double Cluster made this field suitable for the test of this possibility.
The very large majority of the galaxies selected in X-ray surveys are active galaxies (e.g. narrow emission line galaxies, Seyfert galaxies etc.). There are however a few examples of normal galaxies, which are sometimes characterized by an X-ray luminosity in excess of what is expected on the basis of their optical appearance. A closer look at these galaxies may reveal the presence of a mini active nucleus or of other processes responsible for the powerful X-ray emission. Here we consider the normal galaxies selected in the Medium Sensitivity Survey and we discuss the properties of the most X-ray luminous one. We show that this object, which has an optical spectrum lacking any evidence of nuclear activity and which has a radio luminosity typical of early type galaxies, is indeed a peculiar galaxy surrounded by a hot (>2 keV) halo extending out to a radius of 300 kpc, implying a total mass of ∼3 × 1013 M⊙.
An almost fully automatic scheme has been developed which produces final positions in the system determined by the reference catalogue, cross identifications, and approximate magnitudes in a standard system. A plate-overlap method is used which permits inclusion of higher order terms either plate by plate or common to a subset of plates. Magnitude dependent errors are also included. The system has already been applied to more than 500 plates, most of them of the Paris zone, with smaller sets of the Oxford, Potsdam, and Helsingfors zones. The Paris zone yields consistent higher order and magnitude terms over the entire set analyzed so far.
Studies of the evolution of X-ray emission from clusters of galaxies have so far used optically discovered distant clusters then observed at X-ray wavelengths. A different approach to the study of cluster evolution is to use clusters selected directly by their X-ray emission since X-ray selection is extremely successful at discovering high redshift clusters (up to z = 0.5). The Extension of the Medium Sensitivity Survey (Gioia, Maccacaro and Wolter, 1987), a flux limited sample of serendipitous X-ray sources discovered with the Einstein IPC, has been used to select 68 optically identified clusters and 66 possible candidates (using X-ray isointensity maps and optical POSS and ESO prints). Their X-ray fluxes are in the range 10−13 – 10−12 ergs cm−2 s−1 in the 0.3–3.5 keV energy band. Few misidentifications are expected, thus the results presented here have to be considered as preliminary. This sample can be used to study the X-ray logN-logS, the cluster luminosity function and its possible evolution with cosmic time, and also to compare the properties of X-ray selected clusters with those of samples selected by other techniques. Since the identification process is still in progress, and has not proceeded completely at random, the subset of identified sources is not representative of the entire population. With this caveat in mind we have constructed the redshift and X-ray luminosity distributions for the clusters for which we have spectroscopic observations. 68% of the clusters are at z > 0.1, 34% at z > 0.2, and 12% at z > 0.3. Their X-ray luminosities range from about 3 × 1042 to 1045 ergs s−1. At present the lack of a redshift determination for many of the cluster candidates in our sample prevents us from studying the cluster luminosity function. W e can however derive their logN(>S)-logS relation.
Few trials have compared psychosocial therapies for people with bipolar affective disorder, and conventional meta-analyses provided limited comparisons between therapies.
To combine evidence for the efficacy of psychosocial interventions used as adjunctive treatment of bipolar disorder in adults, using network meta-analysis (NMA).
Systematic review identified studies and NMA was used to pool data on relapse to mania or depression, medication adherence, and symptom scales for mania, depression and Global Assessment of Functioning (GAF).
Carer-focused interventions significantly reduced the risk of depressive or manic relapse. Psychoeducation alone and in combination with cognitive–behavioural therapy (CBT) significantly reduced medication non-adherence. Psychoeducation plus CBT significantly reduced manic symptoms and increased GAF. No intervention was associated with a significant reduction in depression symptom scale scores.
Only interventions for family members affected relapse rates. Psychoeducation plus CBT reduced medication non-adherence, improved mania symptoms and GAF. Novel methods for addressing depressive symptoms are required.
The Antarctic Roadmap Challenges (ARC) project identified critical requirements to deliver high priority Antarctic research in the 21st century. The ARC project addressed the challenges of enabling technologies, facilitating access, providing logistics and infrastructure, and capitalizing on international co-operation. Technological requirements include: i) innovative automated in situ observing systems, sensors and interoperable platforms (including power demands), ii) realistic and holistic numerical models, iii) enhanced remote sensing and sensors, iv) expanded sample collection and retrieval technologies, and v) greater cyber-infrastructure to process ‘big data’ collection, transmission and analyses while promoting data accessibility. These technologies must be widely available, performance and reliability must be improved and technologies used elsewhere must be applied to the Antarctic. Considerable Antarctic research is field-based, making access to vital geographical targets essential. Future research will require continent- and ocean-wide environmentally responsible access to coastal and interior Antarctica and the Southern Ocean. Year-round access is indispensable. The cost of future Antarctic science is great but there are opportunities for all to participate commensurate with national resources, expertise and interests. The scope of future Antarctic research will necessitate enhanced and inventive interdisciplinary and international collaborations. The full promise of Antarctic science will only be realized if nations act together.
Historically, alloy development with better radiation performance has been focused on traditional alloys with one or two principal element(s) and minor alloying elements, where enhanced radiation resistance depends on microstructural or nanoscale features to mitigate displacement damage. In sharp contrast to traditional alloys, recent advances of single-phase concentrated solid solution alloys (SP-CSAs) have opened up new frontiers in materials research. In these alloys, a random arrangement of multiple elemental species on a crystalline lattice results in disordered local chemical environments and unique site-to-site lattice distortions. Based on closely integrated computational and experimental studies using a novel set of SP-CSAs in a face-centered cubic structure, we have explicitly demonstrated that increasing chemical disorder can lead to a substantial reduction in electron mean free paths, as well as electrical and thermal conductivity, which results in slower heat dissipation in SP-CSAs. The chemical disorder also has a significant impact on defect evolution under ion irradiation. Considerable improvement in radiation resistance is observed with increasing chemical disorder at electronic and atomic levels. The insights into defect dynamics may provide a basis for understanding elemental effects on evolution of radiation damage in irradiated materials and may inspire new design principles of radiation-tolerant structural alloys for advanced energy systems.
School-based psychological interventions encompass: universal interventions targeting youth in the general population; and indicated interventions targeting youth with subthreshold depression. This study aimed to: (1) examine the population cost-effectiveness of delivering universal and indicated prevention interventions to youth in the population aged 11–17 years via primary and secondary schools in Australia; and (2) compare the comparative cost-effectiveness of delivering these interventions using face-to-face and internet-based delivery mechanisms.
We reviewed literature on the prevention of depression to identify all interventions targeting youth that would be suitable for implementation in Australia and had evidence of efficacy to support analysis. From this, we found evidence of effectiveness for the following intervention types: universal prevention involving group-based psychological interventions delivered to all participating school students; and indicated prevention involving group-based psychological interventions delivered to students with subthreshold depression. We constructed a Markov model to assess the cost-effectiveness of delivering universal and indicated interventions in the population relative to a ‘no intervention’ comparator over a 10-year time horizon. A disease model was used to simulate epidemiological transitions between three health states (i.e., healthy, diseased and dead). Intervention effect sizes were based on meta-analyses of randomised control trial data identified in the aforementioned review; while health benefits were measured as Disability-adjusted Life Years (DALYs) averted attributable to reductions in depression incidence. Net costs of delivering interventions were calculated using relevant Australian data. Uncertainty and sensitivity analyses were conducted to test model assumptions. Incremental cost-effectiveness ratios (ICERs) were measured in 2013 Australian dollars per DALY averted; with costs and benefits discounted at 3%.
Universal and indicated psychological interventions delivered through face-to-face modalities had ICERs below a threshold of $50 000 per DALY averted. That is, $7350 per DALY averted (95% uncertainty interval (UI): dominates – 23 070) for universal prevention, and $19 550 per DALY averted (95% UI: 3081–56 713) for indicated prevention. Baseline ICERs were generally robust to changes in model assumptions. We conducted a sensitivity analysis which found that internet-delivered prevention interventions were highly cost-effective when assuming intervention effect sizes of 100 and 50% relative to effect sizes observed for face-to-face delivered interventions. These results should, however, be interpreted with caution due to the paucity of data.
School-based psychological interventions appear to be cost-effective. However, realising efficiency gains in the population is ultimately dependent on ensuring successful system-level implementation.
Data were pooled from three Australian sentinel general practice influenza surveillance networks to estimate Australia-wide influenza vaccine coverage and effectiveness against community presentations for laboratory-confirmed influenza for the 2012, 2013 and 2014 seasons. Patients presenting with influenza-like illness at participating GP practices were swabbed and tested for influenza. The vaccination odds of patients testing positive were compared with patients testing negative to estimate influenza vaccine effectiveness (VE) by logistic regression, adjusting for age group, week of presentation and network. Pooling of data across Australia increased the sample size for estimation from a minimum of 684 to 3,683 in 2012, from 314 to 2,042 in 2013 and from 497 to 3,074 in 2014. Overall VE was 38% [95% confidence interval (CI) 24–49] in 2012, 60% (95% CI 45–70) in 2013 and 44% (95% CI 31–55) in 2014. For A(H1N1)pdm09 VE was 54% (95% CI–28 to 83) in 2012, 59% (95% CI 33–74) in 2013 and 55% (95% CI 39–67) in 2014. For A(H3N2), VE was 30% (95% CI 14–44) in 2012, 67% (95% CI 39–82) in 2013 and 26% (95% CI 1–45) in 2014. For influenza B, VE was stable across years at 56% (95% CI 37–70) in 2012, 57% (95% CI 30–73) in 2013 and 54% (95% CI 21–73) in 2014. Overall VE against influenza was low in 2012 and 2014 when A(H3N2) was the dominant strain and the vaccine was poorly matched. In contrast, overall VE was higher in 2013 when A(H1N1)pdm09 dominated and the vaccine was a better match. Pooling data can increase the sample available and enable more precise subtype- and age group-specific estimates, but limitations remain.
One of the continuing problems facing Commission 24 is its name. It has been known and reported for some years that the present title is not suitable for reasons that are all too obvious. This problem has continued during the last three years, despite the growing development and use of non-photographic methods and techniques.
Most of the recent meeting activity in which the Commission and its membership has been involved, has centered on its shared interests with Commission 8 and with the Working Group on reference frames formed at the last General Assembly. Since its inception at that time, C. A. Murray has been appointed to represent the Commission on that group.
The question of the title of Commission 24, obviously, offers a difficult problem as already mentioned in recent reports. Photographic Astrometry no longer describes the whole scope of the commission. This problem has continued during the last three years especially in view of the preparations for the astrometric tasks of the NASA Space Telescope and of the ESA satellite HIPPARCOS.
During the past three years there has been increased activity in many fields where photometric methods are employed; more telescopes have been commissioned or adapted for photometric measurements and new magnitude systems have been proposed and tried, but much of the observing is now of a routine nature. Most of this continues to be done in the wide-band UBV system, but more measurements are now being made in the red and infra-red.
More interest is being shown in narrower band-widths that emphasize particular features of a stellar spectrum, because these offer better prospects of separating the effects of temperature, luminosity, interstellar reddening, composition and duplicity. Attention has been given to finding the most useful bands and practical ways of measuring them, both photoelectrically and photographically.
In developing countries in Latin America, Asia, and Africa, light pollution takes a particular aspect due to the social and economical situation. The official reluctance to solve unpopular problems combined with a generalized ignorance create a hostile climate for any campaign in favor of astronomical observatories or amateur associations. The tropical climate makes most energy savings measures unnecessary. Obsolete industrial installations make the application of particle output control difficult or impossible. The most important contribution to air pollution, however, comes from forest fires, some of them as a cheap clearing method, others as an expressions of political discontent. To this must be added that most countries do not have yet a legislature which would permit the imposition of pollution control.
Results for a near-infrared objective-prism survey for faint cool carbon stars in a Carina region centred at l = 290°, b = 0° are presented. A total of 37 identified carbon stars in area of about 16 square degrees were found, of which 4 are new discoveries. Accurate positions, IRAS identifications, infrared fluxes and colours, and associations of the stars in the sample axe given.