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 evidence linking low-carbohydrate diets (LCD) to CVD is controversial, and results from epidemiological studies are inconsistent. We aimed to assess the relationship between LCD patterns and coronary artery Ca (CAC) scores from computed tomography in the Multi-Ethnic Study of Atherosclerosis cohort. Our sample included 5614 men and women free of clinical CVD at baseline (2000–2002), who had a FFQ, a baseline measure and ≥1 measure of CAC during follow-up. We excluded those with implausible energy intake or daily physical activity. The overall, animal-based and plant-based LCD scores were calculated based on intakes of macronutrients. Relative risk regression and robust regression models were used to examine the cross-sectional and longitudinal relationship between LCD score quintile and CAC outcomes, after adjustment for multiple cardiovascular risk factors. The mean age of participants was 63 years. The median intakes of total carbohydrate, fat and protein were 53·7, 30·5 and 15·6 % energy/d, respectively. Among 2892 participants with zero CAC scores at baseline, 264 developed positive scores during 2·4-year follow-up (11–59 months). Among those with positive scores at baseline, the median increase in CAC was 47 units over the course of follow-up. The overall, the animal-based and the plant-based LCD scores were not associated with CAC prevalence, incidence and progression. In conclusion, diets low in carbohydrate and high in fat and/or protein, regardless of the sources of protein and fat, were not associated with higher levels of CAC, a validated predictor of cardiovascular events, in this large multi-ethnic cohort.
The role that vitamin D plays in pulmonary function remains uncertain. Epidemiological studies reported mixed findings for serum 25-hydroxyvitamin D (25(OH)D)–pulmonary function association. We conducted the largest cross-sectional meta-analysis of the 25(OH)D–pulmonary function association to date, based on nine European ancestry (EA) cohorts (n 22 838) and five African ancestry (AA) cohorts (n 4290) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Data were analysed using linear models by cohort and ancestry. Effect modification by smoking status (current/former/never) was tested. Results were combined using fixed-effects meta-analysis. Mean serum 25(OH)D was 68 (sd 29) nmol/l for EA and 49 (sd 21) nmol/l for AA. For each 1 nmol/l higher 25(OH)D, forced expiratory volume in the 1st second (FEV1) was higher by 1·1 ml in EA (95 % CI 0·9, 1·3; P<0·0001) and 1·8 ml (95 % CI 1·1, 2·5; P<0·0001) in AA (Prace difference=0·06), and forced vital capacity (FVC) was higher by 1·3 ml in EA (95 % CI 1·0, 1·6; P<0·0001) and 1·5 ml (95 % CI 0·8, 2·3; P=0·0001) in AA (Prace difference=0·56). Among EA, the 25(OH)D–FVC association was stronger in smokers: per 1 nmol/l higher 25(OH)D, FVC was higher by 1·7 ml (95 % CI 1·1, 2·3) for current smokers and 1·7 ml (95 % CI 1·2, 2·1) for former smokers, compared with 0·8 ml (95 % CI 0·4, 1·2) for never smokers. In summary, the 25(OH)D associations with FEV1 and FVC were positive in both ancestries. In EA, a stronger association was observed for smokers compared with never smokers, which supports the importance of vitamin D in vulnerable populations.
Anxiety is among the most frequently studied emotions in second language acquisition (SLA). Study abroad (SA) researchers have examined its effects on SLA in that setting in a number of studies. The current study goes beyond previous SA research by examining how anxiety develops and connects with language proficiency development over SA. Specifically, it uses anxiety-related measures of foreign language classroom anxiety (FLCA), foreign language enjoyment (FLE), and a physiological manifestation of anxiety (hair cortisol). As far as the classroom is concerned, learners grew more comfortable, experiencing less anxiety and more enjoyment over the period of SA. However, learners showed physiological signs of overall elevated anxiety despite these increasing classroom comfort levels. Two key factors that may have influenced their anxiety levels abroad were tendency toward anxiety prior to SA and language proficiency upon departure for SA. The latter provides support for having students more proficient prior to SA, since doing so may lead to less anxiety during SA.
Eddy covariance data collected over a horizontal surface on the largest ice body on Kilimanjaro, Tanzania, over 26–29 July 2005 were used to assess the uncertainty of calculating sublimation with a surface energy balance (SEB) model. Data required for input to the SEB model were obtained from an existing automatic weather station. Surface temperatures that were solved iteratively by the SEB model were used to compute emitted longwave radiation, turbulent heat fluxes using the aerodynamic bulk method and the subsurface heat flux. Roughness lengths for momentum and temperature, which were found to be the most important input parameters controlling the magnitude of modelled (bulk method) turbulent heat fluxes, were obtained using eddy covariance data. The roughness length for momentum was estimated to be 1.7×10–3 m, while the length for temperature was one order of magnitude smaller. Modelled sensible and latent heat fluxes (bulk method) compared well to eddy covariance data, with root-mean-square differences between 3.1 and 4.8 Wm–2 for both turbulent heat fluxes. Modelled sublimation accounted for about 90% of observed ablation, confirming that mass loss by melting is much less important than sublimation on the horizontal surfaces of the remaining plateau glaciers on Kilimanjaro.
Snowmelt regions on Greenland ice are mapped daily with the SeaWinds wideswath Ku-band (13.4 GHz) scatterometer on the QuikSCAT satellite. The approach exploits the high temporal resolution of SeaWinds/QuikSCAT data for the melt mapping using diurnal backscatter change independent of the absolute calibration. The results reveal several pronounced melting and refreezing events, and effects of topography are evident in the melt patterns. The spatial resolution is sufficient to identify melt features on the Sukker-toppen Iskappe west of the main ice sheet. An anomalous warming event, caused by down-ward mixing of warm air, is detected in late September 1999 over the west flank of the southern Greenland ice sheet. Time-series images of melt regions are presented over the period from summer to the fall freeze-up. The satellite observations are verified with in situ measurements from the Greenland Climate Network stations.
Deriving glacier outlines from satellite data has become increasingly popular in the past decade. In particular when glacier outlines are used as a base for change assessment, it is important to know how accurate they are. Calculating the accuracy correctly is challenging, as appropriate reference data (e.g. from higher-resolution sensors) are seldom available. Moreover, after the required manual correction of the raw outlines (e.g. for debris cover), such a comparison would only reveal the accuracy of the analyst rather than of the algorithm applied. Here we compare outlines for clean and debris-covered glaciers, as derived from single and multiple digitizing by different or the same analysts on very high- (1 m) and medium-resolution (30 m) remote-sensing data, against each other and to glacier outlines derived from automated classification of Landsat Thematic Mapper data. Results show a high variability in the interpretation of debris-covered glacier parts, largely independent of the spatial resolution (area differences were up to 30%), and an overall good agreement for clean ice with sufficient contrast to the surrounding terrain (differences ∼5%). The differences of the automatically derived outlines from a reference value are as small as the standard deviation of the manual digitizations from several analysts. Based on these results, we conclude that automated mapping of clean ice is preferable to manual digitization and recommend using the latter method only for required corrections of incorrectly mapped glacier parts (e.g. debris cover, shadow).
We report on the EPICA Dronning Maud Land (East Antarctica) deep drilling operation. Starting with the scientific questions that led to the outline of the EPICA project, we introduce the setting of sister drillings at NorthGRIP and EPICA Dome C within the European ice-coring community. The progress of the drilling operation is described within the context of three parallel, deep-drilling operations, the problems that occurred and the solutions we developed. Modified procedures are described, such as the monitoring of penetration rate via cable weight rather than motor torque, and modifications to the system (e.g. closing the openings at the lower end of the outer barrel to reduce the risk of immersing the drill in highly concentrated chip suspension). Parameters of the drilling (e.g. core-break force, cutter pitch, chips balance, liquid level, core production rate and piece number) are discussed. We also review the operational mode, particularly in the context of achieved core length and piece length, which have to be optimized for drilling efficiency and core quality respectively. We conclude with recommendations addressing the design of the chip-collection openings and strictly limiting the cable-load drop with respect to the load at the start of the run.
We assess the runoff and surface mass balance (SMB) of the Greenland ice sheet in the Nuuk region (southwest) using output of two regional climate models (RCMs) evaluated by observations. The region encompasses six glaciers that drain into Godthåbsfjord. RCM data (1960–2012) are resampled to a high spatial resolution to include the narrow (relative to the native grid spacing) glacier trunks in the ice mask. Comparing RCM gridded results with automatic weather station (AWS) point measurements reveals that locally models can underestimate ablation and overestimate accumulation by up to tens of per cent. However, comparison with lake discharge indicates that modelled regional runoff totals are more accurate. Model results show that melt and runoff in the Nuuk region have doubled over the past two decades. Regional SMB attained negative values in recent high-melt years. Taking into account frontal ablation of the marine-terminating glaciers, the region lost 10–20 km3 w.e. a–1 in 2010–12. If 2010 melting prevails during the remainder of this century, a low-end estimate of sea-level rise of 5 mm is expected by 2100 from this relatively small section (2.6%) of the ice sheet alone.
The third symposium on Remote Sensing of Snow and Ice, organized by the International Glaciological Society, took place in Boulder, Colorado, 17–22 May 1992. As part of this meeting a total of 21 papers was presented on snow and ice applications of Advanced Very High Resolution Radiometer (AVHRR) satellite data in polar regions. Also during this meeting a NASA sponsored Workshop was held to review the status of polar surface measurements from AVHRR. In the following we have summarized the ideas and recommendations from the workshop, and the conclusions of relevant papers given during the regular symposium sessions. The seven topics discussed include cloud masking, ice surface temperature, narrow-band albedo, ice concentration, lead statistics, sea-ice motion and ice-sheet studies with specifics on applications, algorithms and accuracy, following recommendations for future improvements. In general, we can affirm the strong potential of AVHRR for studying sea ice and snow covered surfaces, and we highly recommend this satellite data set for long-term monitoring of polar process studies. However, progress is needed to reduce the uncertainty of the retrieved parameters for all of the above mentioned topics to make this data set useful for direct climate applications such as heat balance studies and others. Further, the acquisition and processing of polar AVHRR data must become better coordinated between receiving stations, data centers and funding agencies to guarantee a long-term commitment to the collection and distribution of high quality data.
Safeguarding threatened species in captivity is a promising management approach, but evaluating the performance of captive programmes is essential to assess reintroduction potential. The eastern population of the Northern Bald Ibis, Geronticus eremita, used to be a locally common migratory bird species, but catastrophic population declines throughout the past century have resulted in a single population in southern Turkey that forages freely during summer but only survives in captivity during winter. We examined whether breeding success of this semi-wild colony was comparable to breeding success of previous wild populations, and to what extent breeding success was influenced by supplementary feeding and wild foraging in habitats near the breeding station. Average productivity from 2009 to 2015 was 1.12 fledglings per nesting pair (range 0.96–1.19). In 2013 and 2014, there was no correlation between attendance at supplementary feeding events and productivity, and breeding birds attended on average only 35% of supplementary feeding events. Birds that were frequently observed at a local tree nursery raised fewer offspring, while birds observed more frequently in poldered cultivation, and in particular in mint crops or in fields covered with manure, raised on average more offspring. Foraging success was highest in meadows and cropland, particularly in mint crops and fields covered in manure, and lowest at the tree nursery. We speculate that selection of highly suitable wild foraging habitat such as mint crops or fields covered in manure allows the Northern Bald Ibis to raise more fledglings than exclusive reliance on supplementary food provided at the breeding station. Establishing a second breeding colony of this species in Turkey will therefore require a careful assessment of the suitability of wild foraging habitat in the vicinity of suitable nesting opportunities.
The role of episodic mass loss in evolved massive stars is one of the outstanding questions in stellar evolution theory. Integral field spectroscopy of nebulae around massive stars provide information on their recent mass-loss history. η Car is one of the most massive evolved stars and is surrounded by a complex circumstellar environment. We have conducted a three-dimensional morpho-kinematic analysis of η Car’s ejecta outside its famous Homunculus nebula. SHAPE modelling of VLT MUSE data establish unequivocally the spatial cohesion of the outer ejecta and the correlation of ejecta with the soft X-ray emission.
Glacier surface mass-balance measurements on Greenland started more than a century ago, but no compilation exists of the observations from the ablation area of the ice sheet and local glaciers. Such data could be used in the evaluation of modelled surface mass balance, or to document changes in glacier melt independently from model output. Here, we present a comprehensive database of Greenland glacier surface mass-balance observations from the ablation area of the ice sheet and local glaciers. The database spans the 123 a from 1892 to 2015, contains a total of ~3000 measurements from 46 sites, and is openly accessible through the PROMICE web portal (http://www.promice.dk). For each measurement we provide X, Y and Z coordinates, starting and ending dates as well as quality flags. We give sources for each entry and for all metadata. Two thirds of the data were collected from grey literature and unpublished archive documents. Roughly 60% of the measurements were performed by the Geological Survey of Denmark and Greenland (GEUS, previously GGU). The data cover all regions of Greenland except for the southernmost part of the east coast, but also emphasize the importance of long-term time series of which there are only two exceeding 20 a. We use the data to analyse uncertainties in point measurements of surface mass balance, as well as to estimate surface mass-balance profiles for most regions of Greenland.
This paper briefly describes the principle of operation and science goals of the AMANDA high energy neutrino telescope located at the South Pole, Antarctica. Results from an earlier phase of the telescope, called AMANDA-BIO, demonstrate both reliable operation and the broad astrophysical reach of this device, which includes searches for a variety of sources of ultrahigh energy neutrinos: generic point sources, Gamma-Ray Bursts and diffuse sources. The predicted sensitivity and angular resolution of the telescope were confirmed by studies of atmospheric muon and neutrino backgrounds. We also report on the status of the analysis from AMANDA-II, a larger version with far greater capabilities. At this stage of analysis, details of the ice properties and other systematic uncertainties of the AMANDA-II telescope are under study, but we have made progress toward critical science objectives. In particular, we present the first preliminary flux limits from AMANDA-II on the search for continuous emission from astrophysical point sources, and report on the search for correlated neutrino emission from Gamma Ray Bursts detected by BATSE before decommissioning in May 2000. During the next two years, we expect to exploit the full potential of AMANDA-II with the installation of a new data acquisition system that records full waveforms from the in-ice optical sensors.
Up to now, hydrodynamical models of dust-driven AGB winds do not generally take into account the ‘long-term’ changes of the stellar parameters (on stellar evolution time scales of 103 to 105 yrs), although it is well known that the luminosity and (very likely) the mass loss rate undergo significant variations when so called ‘thermal pulses’ occur on the upper AGB. In this review we demonstrate that time-dependent radiation hydrodynamics calculations are needed to understand the formation, structure, and spectral energy distribution of detached dust shells detected by IRAS and ISO. Combined with appropriate models, these observations can reveal part of the previous mass loss history on the AGB and allow an empirical check of presently adopted mass loss laws.
Based on insights from hydrodynamical simulations, we discuss the two competing scenarios that have been put forward to explain the origin of the very thin molecular shells recently discovered around some carbon stars. We find that the signature of a short mass loss ‘eruption’ broadens quickly with time due to the related velocity gradient across the shell. Hence, this scenario is not considered a likely explanation of detached CO shells. On the other hand, the alternative mechanism, interaction of winds, is shown to be capable of producing very thin shells of greatly enhanced gas density in the dusty outflows from AGB stars by sweeping up matter at the interface between both type of winds.
We investigate the international linkages of uncertainty associated with the long-term movements of inflation. In the first step, we establish that inflation uncertainty in the G7 is intertwined, and the degree of synchronization has increased during the recent two decades. We also document a rise in inflation uncertainty accompanying the global financial crisis. Based on a factor–structural vector autoregression, we provide evidence of a common international shock. We disclose that this shock is closely related to oil and commodity price uncertainty, and it explains large parts of the recent rise in inflation uncertainty. Moreover, increased synchronization can be explained by greater relative importance of this global shock. We also document that inflation uncertainty has become more stable, because domestic shocks translate less extensively into individual economies. This finding lends support to the “good policy” hypothesis.
Depression in late life is a risk factor for cognitive decline. Depression is also associated with increased disability and social support deficits; these may precede conversion to dementia and inform risk. In this study, we examined if baseline or one-year change in disability and social support predicted later cognitive deterioration.
299 cognitively intact depressed older adults were followed for an average of approximately seven years. Participants received antidepressant treatment according to a standardized algorithm. Neuropsychological testing and assessment of disability and social support were assessed annually. Cognitive diagnosis was reviewed annually at a consensus conference to determine if participants remained cognitively normal, or if they progressed to either dementia or cognitively impaired, no dementia (CIND).
During study participation, 167 individuals remained cognitively normal (56%), 83 progressed to CIND (28%), and 49 progressed to dementia (16%). Greater baseline instrumental activities of daily living (IADL) deficits predicted subsequent conversion to a cognitive diagnosis (CIND or dementia). However, neither baseline measures nor one-year change in basic ADLs (BADLs) and social support predicted cognitive conversion. In post hoc analyses, two IADL measures (managing finances, preparing meals) significantly increased the odds of cognitive conversion.
Greater IADL deficits predicted increased risk of cognitive conversion. Assessment of IADL deficits may provide clues about risk of later cognitive decline.
In this response to commentaries, we revisit the two main arguments of our target article. Based on data drawn from a variety of research areas – vocal behavior in nonhuman primates, speech physiology and pathology, neurobiology of basal ganglia functions, motor skill learning, paleoanthropological concepts – the target article, first, suggests a two-stage model of the evolution of the crucial motor prerequisites of spoken language within the hominin lineage: (1) monosynaptic refinement of the projections of motor cortex to brainstem nuclei steering laryngeal muscles, and (2) subsequent “vocal-laryngeal elaboration” of cortico-basal ganglia circuits, driven by human-specific FOXP2 mutations. Second, as concerns the ontogenetic development of verbal communication, age-dependent interactions between the basal ganglia and their cortical targets are assumed to contribute to the time course of the acquisition of articulate speech. Whereas such a phylogenetic reorganization of cortico-striatal circuits must be considered a necessary prerequisite for ontogenetic speech acquisition, the 30 commentaries – addressing the whole range of data sources referred to – point at several further aspects of acoustic communication which have to be added to or integrated with the presented model. For example, the relationships between vocal tract movement sequencing – the focus of the target article – and rhythmical structures of movement organization, the connections between speech motor control and the central-auditory and central-visual systems, the impact of social factors upon the development of vocal behavior (in nonhuman primates and in our species), and the interactions of ontogenetic speech acquisition – based upon FOXP2-driven structural changes at the level of the basal ganglia – with preceding subvocal stages of acoustic communication as well as higher-order (cognitive) dimensions of phonological development. Most importantly, thus, several promising future research directions unfold from these contributions – accessible to clinical studies and functional imaging in our species as well as experimental investigations in nonhuman primates.
The Mediterranean diet has been reported to be inversely associated with incident metabolic syndrome (MetSyn) among older adults; however, this association has not been studied in young African American and white adults. The objective of the present study was to evaluate the association of a modified Mediterranean diet (mMedDiet) score with the 25-year incidence of the MetSyn in 4713 African American and white adults enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. A diet history questionnaire was used to assess dietary intake at baseline, year 7 and year 20 and a mMedDiet score was created. Cardiovascular risk factors were measured at multiple examinations over 25 years. The MetSyn was defined according to the National Cholesterol Education Program Adult Treatment Panel III (ATP III) criteria. Cox proportional-hazards regression analysis was use to evaluate associations for incident MetSyn across the mMedDiet score categories adjusting for demographic characteristics, lifestyle factors and BMI. Higher mMedDiet scores represented adherence to a dietary pattern rich in fruit, vegetables, whole grains, nuts and fish, but poor in red and processed meat and snack foods. The incidence of MetSyn components (abdominal obesity, elevated TAG concentrations and low HDL-cholesterol concentrations) was lower in those with higher mMedDiet scores than in those with lower scores. Furthermore, the incidence of the MetSyn was lower across the five mMedDiet score categories; the hazard ratios and 95 % CI from category 1 to category 5 were 1·0; 0·94 (0·76, 1·15); 0·84 (0·68, 1·04); 0·73 (0·58, 0·92); and 0·72 (0·54, 0·96), respectively (Ptrend= 0·005). These findings suggest that the risk of developing the MetSyn is lower when consuming a diet rich in fruit, vegetables, whole grains, nuts and fish.