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The Subglacial Antarctic Lakes Scientific Access (SALSA) Project accessed Mercer Subglacial Lake using environmentally clean hot-water drilling to examine interactions among ice, water, sediment, rock, microbes and carbon reservoirs within the lake water column and underlying sediments. A ~0.4 m diameter borehole was melted through 1087 m of ice and maintained over ~10 days, allowing observation of ice properties and collection of water and sediment with various tools. Over this period, SALSA collected: 60 L of lake water and 10 L of deep borehole water; microbes >0.2 μm in diameter from in situ filtration of ~100 L of lake water; 10 multicores 0.32–0.49 m long; 1.0 and 1.76 m long gravity cores; three conductivity–temperature–depth profiles of borehole and lake water; five discrete depth current meter measurements in the lake and images of ice, the lake water–ice interface and lake sediments. Temperature and conductivity data showed the hydrodynamic character of water mixing between the borehole and lake after entry. Models simulating melting of the ~6 m thick basal accreted ice layer imply that debris fall-out through the ~15 m water column to the lake sediments from borehole melting had little effect on the stratigraphy of surficial sediment cores.
Analyses of macroscopic charcoal, sediment geochemistry (%C, %N, C/N, δ13C, δ15N), and fossil pollen were conducted on a sediment core recovered from Stella Lake, Nevada, establishing a 2000 year record of fire history and vegetation change for the Great Basin. Charcoal accumulation rates (CHAR) indicate that fire activity, which was minimal from the beginning of the first millennium to AD 750, increased slightly at the onset of the Medieval Climate Anomaly (MCA). Observed changes in catchment vegetation were driven by hydroclimate variability during the early MCA. Two notable increases in CHAR, which occurred during the Little Ice Age (LIA), were identified as major fire events within the catchment. Increased C/N, enriched δ15N, and depleted δ13C values correspond with these events, providing additional evidence for the occurrence of catchment-scale fire events during the late fifteenth and late sixteenth centuries. Shifts in the vegetation community composition and structure accompanied these fires, with Pinus and Picea decreasing in relative abundance and Poaceae increasing in relative abundance following the fire events. During the LIA, the vegetation change and lacustrine geochemical response was most directly influenced by the occurrence of catchment-scale fires, not regional hydroclimate.
This article examines young people’s experiences of open access youth work in settings in the UK, Finland, Estonia, Italy and France. It analyses 844 individual narratives from young people, which communicate the impact of youthwork on their lives. These accounts are then analysed in the light of the European youth work policy goals. It concludes that it is encouraging that what young people identify as the positive impact of youth work are broadly consistent with many of these goals. There are however some disparities which require attention. These include the importance young people place on the social context of youth work, such as friendship, which is largely absent in EU youth work policy; as well as the importance placed on experiential learning. The paper also highlights a tension between ‘top down’ policy formulation and the ‘youth centric’ practices of youth work. It concludes with a reminder to policy makers that for youth work to remain successful the spaces and places for young people must remain meaningful to them ‘on their terms’.
Beginning with loose aggregations of dust particles coated with heterogeneous ices under vacuum at Kuiper Belt temperatures, moving to Jupiter/Saturn distances and eventually to low-perihelion orbit, we consider the likely development of the gaseous phase within a cometary nucleus over the course of its lifetime. From the perspective of physical chemistry, we consider limits on the spatial and temporal distribution and composition of this gaseous phase. The implications of the gaseous phase for heat transfer and for the possible spatial and temporal development of liquid phases are calculated. We conclude that the likely temperatures, pressures, and compositions beneath the outer crust of typical cometary nuclei are such that fluidised phases can exist at significant depths and that these reservoirs give a coherent explanation for the high-intensity outbursts observed from cometary nuclei at large distances from perihelion.
Pelagic seabirds often nest on islands that are far from productive foraging areas. The Procellariiformes (petrels, shearwaters and albatrosses) are among the longest-ranging seabirds; they have several adaptations that permit them to efficiently utilize distant foraging areas and fast for long periods during incubation (Phillips & Hamer 1999). Giant petrels (Macronectes spp.) are large surface-nesting procellariiforms. They feed both by direct predation and by scavenging carrion, and they are the largest avian predator-scavengers in the Southern Ocean. Among procellariiform seabirds, one partner forages while their mate remains on the nest to incubate their single egg (Warham 1990). Northern giant petrels (Macronectes halli) have incubation shifts lasting up to 17 days (Cooper et al. 2001). In general, incubating procellariiform seabirds do not feed during their shift (Warham 1990). We report the first case to our knowledge of a procellariiform seabird, a northern giant petrel, actively feeding at its nest whilst incubating.
Hydrilla is an invasive aquatic plant that has rapidly spread through many inland water bodies across the globe by outcompeting native aquatic plants. The negative impacts of hydrilla invasion have become a concern for water resource management authorities, power companies, and environmental scientists. The early detection of hydrilla infestation is very important to reduce the costs associated with control and removal efforts of this invasive species. Therefore, in this study, we aimed to develop a tool for rapid, frequent, and large-scale monitoring and predicting spatial extent of hydrilla habitat. This was achieved by integrating in situ and Landsat 8 Operational Land Imager satellite data for Lake J. Strom Thurmond, the largest US Army Corps of Engineers lake east of the Mississippi River, located on the border of Georgia and South Carolina border. The predictive model for presence of hydrilla incorporated radiometric and physical measurements, including remote-sensing reflectance, Secchi disk depth (SDD), light-attenuation coefficient (Kd), maximum depth of colonization (Zc), and percentage of light available through the water column (PLW). The model-predicted ideal habitat for hydrilla featured high SDD, Zc, and PLW values, low values of Kd. Monthly analyses based on satellite images showed that hydrilla starts growing in April, reaches peak coverage around October, begins retreating in the following months, and disappears in February. Analysis of physical and meteorological factors (i.e., water temperature, surface runoff, net inflow, precipitation) revealed that these parameters are closely associated with hydrilla extent. Management agencies can use these results not only to plan removal efforts but also to evaluate and adapt their current mitigation efforts.
Graduate-program decision makers face a similar challenge: how to design an admissions process that screens out applicants who are unlikely to succeed but does not provide too high an entry barrier for students who can be successful. This study catalogs the use of standardized testing in Master of Public Administration admissions and finds that less than one third of programs require standardized tests for all applicants. Moreover, program prestige, program diversity, and program size do not affect the likelihood that a program requires the Graduate Record Examination. This study also reviews the various standards that universities use to provide test waivers and also discusses other common application materials. The results should be of interest to undergraduate academic advisers and graduate-program directors as well as scholars and practitioners of higher-education administration more generally.
High quality evidence for test accuracy can be scarce. We assessed the test accuracy of two tests (Actim Partus and PartoSure) for the prediction of preterm birth. Twenty published full-text papers were included whilst conference abstracts were excluded. Since systematic reviews of diagnostic tests on other topics may need to rely on data from conference abstracts, we test whether the findings of our review would change with conference abstracts included.
Conference citations previously excluded (n=108) were re-screened for inclusion using the following criteria: i) the diagnostic test was Actim Partus or PartoSure ii) test accuracy data of preterm delivery within seven days was reported iii) the population was women with signs/symptoms of preterm labor with intact membranes. Relevant test accuracy data were extracted and used to calculate sensitivity and specificity. Pooled sensitivity and specificity for each test were run using data from full-text papers and conference abstracts combined. These values were compared with the pooled sensitivities and specificities produced for the systematic review using full-text papers only.
Preliminary pooled sensitivities of the sixteen full-text Actim Partus studies and sixteen full-texts and two abstracts were 0.77 (95% confidence interval (CI) 0.68, 0.83) and 0.76 (95% CI 0.69, 0.83) respectively whilst pooled specificities were 0.81 (95% CI 0.76, 0.85).and 0.80 (95% CI 0.75, 0.84) respectively. Preliminary, pooled sensitivities of the four full-text PartoSure studies and four full-texts and three abstracts were 0.83 (95% CI 0.61, 0.94) and 0.82 (95% CI 0.65, 0.92), respectively, whilst pooled specificities were 0.95 (95% CI 0.89, 0.98) and 0.96 (95% CI 0.94, 0.97), respectively.
Our findings suggest that the test accuracy results would not alter substantially with the inclusion of conference abstracts. However, work is ongoing to investigate how the assessment of heterogeneity and risk of bias across studies would alter given the difficulties associated with limited methodological reporting from conference abstracts.
Archaeological fieldwork preceding housing development revealed a Mesolithic site in a primary context. A central hearth was evident from a cluster of calcined flint and bone, the latter producing a modelled date for the start of occupation at 8220–7840 cal bc and ending at 7960–7530 cal bc (95% probability). The principal activity was the knapping of bladelets, the blanks for microlith production. Impact-damaged microliths indicated the re-tooling of hunting weaponry, while microwear analysis of other tools demonstrated hide working and butchery activity at the site. The lithics can be classified as a Honey Hill assemblage type on the basis of distinctive leaf-shaped microlithic points with inverse basal retouch.
Such assemblages have a known concentration in central England and are thought to be temporally intermediate between the conventional British Early and Late Mesolithic periods. The lithic assemblage is compared to other Honey Hill type and related Horsham type assemblages from south-eastern England. Both assemblage types are termed Middle Mesolithic and may be seen as part of wider developments in the late Preboreal and Boreal periods of north-west Europe. Rapid climatic warming at this time saw the northward expansion of deciduous woodland into north-west Europe. Emerging new ecosystems presented changes in resource patterns and the Middle Mesolithic lithic typo-technological developments reflect novel foraging strategies as adaptations to the new opportunities of Boreal forest conditions. While Honey Hill-type assemblages are seen as part of such wider processes their distinctive typological signature attests to autochthonous, regional developments of human groups infilling the landscape. Such cultural insularity may reflect changing social boundaries with reduction in mobility range and physical isolation caused by rising sea level and the creation of the British archipelago.
Congenital abnormalities of the coronary arteries in the absence of structural heart disease account for a small but interesting percentage of cardiac lesions in children. Their presentation may vary from incidental identification to aborted/sudden cardiac death. Patients with aborted sudden death episodes will require significant support if they develop extensive ischaemic myocardial injury. Ultimately, surgical repair should be carried out as soon as haemodynamic stability is attained and the neurological status is evaluated. The aims of this article were to provide a review of congenital abnormalities of the coronary arteries most commonly seen in children in the ICU as well as to review the current critical-care management thereof.
Background: Clinical perfectionism is a risk and maintaining factor for anxiety disorders, depression and eating disorders. Aims: The aim was to examine the psychometric properties of the 12-item Clinical Perfectionism Questionnaire (CPQ). Method: The research involved two samples. Study 1 comprised a nonclinical sample (n = 206) recruited via the internet. Study 2 comprised individuals in treatment for an eating disorder (n = 129) and a community sample (n = 80). Results: Study 1 factor analysis results indicated a two-factor structure. The CPQ had strong correlations with measures of perfectionism and psychopathology, acceptable internal consistency, and discriminative and incremental validity. The results of Study 2 suggested the same two-factor structure, acceptable internal consistency, and construct validity, with the CPQ discriminating between the eating disorder and control groups. Readability was assessed as a US grade 4 reading level (student age range 9–10 years). Conclusions: The findings provide evidence for the reliability and validity of the CPQ in a clinical eating disorder and two separate community samples. Although further research is required the CPQ has promising evidence as a reliable and valid measure of clinical perfectionism.
The interest of organic farmers in adopting conservation agriculture principles, including minimal soil disturbance, permanent soil cover and crop rotation has been growing since the early 2000s. However, currently there is no network for organic farmers practicing conservation agriculture, and a lack of knowledge on how organic farmers implement conservation agriculture in practice. Consequently, few technical references are available for organic farmers when they start applying conservation agriculture practices, in particular on controlling weeds without the use of herbicides. The main objectives of this study were: (1) to explore the diversity of conservation agriculture techniques (i.e., reduced tillage, no-tillage and green manures) practiced among European farmers, and (2) to identify farmers’ main strategies for implementing conservation agriculture and the agronomic and environmental factors that determine these strategies. Strategies were identified by analyzing survey results on: (1) the type and degree of use of conservation agriculture practices by farmers, and (2) the effects it produces in terms of soil disturbance and soil cover (low, medium and high). We carried out a survey of 159 European organic farmers and collected 125 data sets on management of winter-sown crops. Among the conservation agriculture practices, reduced tillage was used by 89%, no-tillage by 27% and green manure by 74% of the 159 interviewed farmers. Green manures were more frequently used in northern Europe than in the south (below 45°N). Most of the farmers used crop rotations, with a mean duration of 6 years. A wide diversity of conservation agriculture practices were used, with farmers rarely using all three techniques (no-till, reduced till and green manures) within one system. The range of practices was grouped into five strategies ranging from intensive non-inversion tillage without soil cover to very innovative techniques with no-tillage and intercrops. The five strategies for conservation agriculture could be grouped into two larger categories based on weed control approach: (1) intensification of the mechanical work without soil inversion or (2) biological regulation of weeds with cover crops. The diversity of strategies identified in this study shows that organic farmers use innovative approaches to implement conservation agriculture without herbicides. This study's findings will help organic farmers to experiment with innovative practices based on conservation agriculture principles and also benefit conventional farmers who use conservation agriculture practices and would like to reduce or eliminate the use of herbicides.