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The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.
Using existing data from clinical registries to support clinical trials and other prospective studies has the potential to improve research efficiency. However, little has been reported about staff experiences and lessons learned from implementation of this method in pediatric cardiology.
We describe the process of using existing registry data in the Pediatric Heart Network Residual Lesion Score Study, report stakeholders’ perspectives, and provide recommendations to guide future studies using this methodology.
The Residual Lesion Score Study, a 17-site prospective, observational study, piloted the use of existing local surgical registry data (collected for submission to the Society of Thoracic Surgeons-Congenital Heart Surgery Database) to supplement manual data collection. A survey regarding processes and perceptions was administered to study site and data coordinating center staff.
Survey response rate was 98% (54/55). Overall, 57% perceived that using registry data saved research staff time in the current study, and 74% perceived that it would save time in future studies; 55% noted significant upfront time in developing a methodology for extracting registry data. Survey recommendations included simplifying data extraction processes and tailoring to the needs of the study, understanding registry characteristics to maximise data quality and security, and involving all stakeholders in design and implementation processes.
Use of existing registry data was perceived to save time and promote efficiency. Consideration must be given to the upfront investment of time and resources needed. Ongoing efforts focussed on automating and centralising data management may aid in further optimising this methodology for future studies.
A passive interplanetary dust collection experiment, currently in orbit aboard LDEF (Long Duration Exposure Facility), is described. The collectors, germanium target plates covered by metallized Mylar foils, are designed for secondary ion mass spectrometry (SIMS) measurements of the elemental and isotopic compositions of residues resulting from micrometeoroid (> 10−10 grams) impacts. Impact simulation experiments have demonstrated the validity of the collection concept. Quantitative elemental analyses are complicated by the non-uniform distribution of projectile-derived elements.
A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
Social context has a major influence on the detection and treatment of youth mental and substance use disorders in socioeconomically disadvantaged urban areas, particularly where gang culture, community violence, normalisation of drug use and repetitive maladaptive family structures prevail. This paper aims to examine how social context influences the development, identification and treatment of youth mental and substance use disorders in socioeconomically disadvantaged urban areas from the perspectives of health care workers.
Semi-structured interviews were conducted with health care workers (n=37) from clinical settings including: primary care, secondary care and community agencies and analysed thematically using Bronfenbrenner’s Ecological Theory to guide analysis.
Health care workers’ engagement with young people was influenced by the multilevel ecological systems within the individual’s social context which included: the young person’s immediate environment/‘microsystem’ (e.g., family relationships), personal relationships in the ‘mesosystem’ (e.g., peer and school relationships), external factors in the young person’s local area context/‘exosystem’ (e.g., drug culture and criminality) and wider societal aspects in the ‘macrosystem’ (e.g., mental health policy, health care inequalities and stigma).
In socioeconomically disadvantaged urban areas, social context, specifically the micro-, meso-, exo-, and macro-system impact both on the young person’s experience of mental health or substance use problems and services, which endeavour to address these problems. Interventions that effectively identify and treat these problems should reflect the additional challenges posed by such settings.
Irish adolescents have one of the highest rates of suicide and self-harm in the European Union. Although primary care has been identified as an opportune environment in which to detect and treat mental health problems in adolescents, lack of training among primary care professionals (PCPs) is a barrier to optimum identification and treatment. We describe the development and evaluation of an educational intervention on youth mental health and substance misuse for PCPs.
Thirty general practitioners and other PCPs working in the Mid-West region participated in an educational session on youth-friendly consultations, and identification and treatment of mental ill-health and substance use. Learning objectives were addressed through a presentation, video demonstration, small group discussions, role play, question-and-answer sessions with clinical experts, and an information pack. Following the session, participants completed an evaluation form assessing knowledge gain and usefulness of different components of the session.
A total of 71% of participants were involved in the provision of care to young people and 55% had no previous training in youth mental health or substance abuse. Participants rated knowledge gains as highest with regard to understanding the importance of early intervention, and primary care, in youth mental health. The components rated as most useful were case studies/small group discussion, the ‘question-and-answer session’ with clinical experts, and peer interaction.
The educational session outlined in this pilot was feasible and acceptable and may represent an effective way to train professionals to help tackle the current crisis in youth mental health.
Cannabis varies considerably in levels of its two major constituent cannabinoids – (delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Recently, we found evidence that those who smoked cannabis containing detectable levels of CBD had fewer psychotic-like symptoms than those whose cannabis had no CBD. The present study aimed, first, to replicate those findings and, second, to determine whether protective effects of CBD may extend to other harms of cannabis, such as memory impairment and reduced psychological well-being.
A total of 120 current cannabis smokers, 66 daily users and 54 recreational users were classified into groups according to whether analysis of their hair revealed the presence or absence of CBD and high versus low levels of THC. All were assessed on measures of psychosis-like symptoms, memory (prose recall; source memory) and depression/anxiety.
Lower psychosis-like symptoms were found in those whose hair had CBD compared with those without. However, this was seen only in recreational users, who had higher levels of THC in their hair. Higher THC levels in hair were associated with increased depression and anxiety. Prose recall and source memory were poorer in daily users with high THC levels in hair while recognition memory was better in individuals with CBD present in hair.
CBD attenuates the psychotic-like effects of cannabis over time in recreational users. Higher THC negatively impacts on memory and psychological well-being. These findings raise concerns for the harms stemming from use of varieties such as ‘skunk’ (sensimillia), which lack any CBD but currently dominate the supply of cannabis in many countries.
We analyze the dependence of the second-order G'-band profile in terms of their (n,m) indices by measuring the resonance Raman spectra of several semiconducting and metalic isolated single wal carbon nanotubes. We show that this profile is very sensitive to the electronic structure, thus making it possible to get structural (n,m) information and to probe the splitting of the van Hove singularities in the electronic density of states due to the trigona warping effect.
We present results from resonant Raman spectroscopy on the graphite-like G band by measuring Raman spectra on isolated single wal carbon nanotubes (SWNTs). We discuss the G-band lineshape dependence on nanotube diameter and chirality, as well as polarization studies related to the antenna effect. Symmetry selection rules, dipolar and multipolar antenna behaviors are discussed. Spectra at the single nanotube level are related to spectra observed from SWNT bundles.
We suggest a new application for elastic scattering of a metastable spin-polarized atomic helium beam at thermal energy. We demonstrate how angle-resolved measurements of the Bragg peaks of scattered surviving metastable atoms can give information about the spin-ordering of an antiferromagnetic (AF) transition metal oxide surface. In this paper, we discuss the feasibility of such measurements for NiO(100) and MnO(100), based on available information about their electronic structure and the properties of spin-polarized metastable helium. On impact with a surface, the survival probability of metastables is generally very low (<10-2). There are two possible decay mechanisms for metastables, a resonance ionization followed by auger neutralization, or an auger de-excitation process. For AF surfaces which fulfill certain requirements on their electronic structure, spin-selection rules will inhibit the decay of the metastable atoms from a favourably aligned magnetic sublattice. The survival probability will then be dramatically enhanced from the chosen sublattice, and the coherently scattered surviving metastables will reflect the periodicity of that magnetic sublattice. In contrast to other methods currently applied to magnetic systems, this method does not rely on difference spectra. Consequently, reversal of spinorientation is not necessary for the observation of magnetic ordering.
Gyps vulture populations across the Indian subcontinent collapsed in the 1990s and continue to decline. Repeated population surveys showed that the rate of decline was so rapid that elevated mortality of adult birds must be a key demographic mechanism. Post mortem examination showed that the majority of dead vultures had visceral gout, due to kidney damage. The realisation that diclofenac, a non-steroidal anti-inflammatory drug potentially nephrotoxic to birds, had become a widely used veterinary medicine led to the identification of diclofenac poisoning as the cause of the decline. Surveys of diclofenac contamination of domestic ungulate carcasses, combined with vulture population modelling, show that the level of contamination is sufficient for it to be the sole cause of the decline. Testing on vultures of meloxicam, an alternative NSAID for livestock treatment, showed that it did not harm them at concentrations likely to be encountered by wild birds and would be a safe replacement for diclofenac. The manufacture of diclofenac for veterinary use has been banned, but its sale has not. Consequently, it may be some years before diclofenac is removed from the vultures' food supply. In the meantime, captive populations of three vulture species have been established to provide sources of birds for future reintroduction programmes.
Although people with schizophrenia display impaired abilities for consent, it is not known how much impairment constitutes incapacity.
To assess a method for determining the categorical capacity status of potential participants in schizophrenia research.
Expert-judgement validation of capacity thresholds on the sub-scales of the MacArthur Competence Assessment Tool – Clinical Research (MacCAT–CR) was evaluated using receiver operating characteristic (ROC) analysis in 91 people with severe mental illness and 40 controls.
The ROC areas under the curve for the understanding, appreciation and reasoning sub-scales of the MacCAT–CR were 0.94 (95% CI 0.88–0.99), 0.85 (95% CI 0.76–0.94) and 0.80 (95% CI 0.70–0.90). These findings yielded negative and positive predictive values of incapacity that can guide the practice of investigators and research ethics committees.
By performing such validation studies for a few categories of research with varying risks and benefits, it might be possible to create evidence-based capacity determination guidelines for most schizophrenia research.
Sheep rearing is a traditional occupation of about 85 000 shepherd families on the Deccan plateau in the Maharashtra State of India. They rear Deccani (D) sheep which usually bear only single lambs. Prolificacy is an important trait for the efficiency of meat producing sheep. It was decided to evaluate and utilize Indian sheep genetic resources with a view to improving the efficiency of sheep production on the Deccan plateau. A crossbreeding experiment was conducted over 4 years, using rams of the D, Bannur (B) and Garole (G) breeds and D and B ewes with the aim of developing recommendations for the appropriate breed combination of a likely composite. It was found that crossing with G reduces live weight and growth rates significantly compared with D but lambs sired by G rams were more resistant to naturally acquired gastro-intestinal nematode infections and to artificial challenge with Haemonchus contortus than those sired by D or B rams. The G breed, being from a humid environment is, however, not adapted to the semi-arid Deccan plateau. The higher productivity (in terms of weight of lamb weaned) of twin-bearing ewes compared with those bearing singles was evident even in extensive rearing conditions. The finding of increased resistance to gastro-intestinal nematodes in the G breed, which also carries a major gene for prolificacy, highlights the potential for inclusion of G in a composite breed. Negative effects on growth and survival from inclusion of the Garole need to be carefully managed.
This paper describes an experimental study of two-dimensional surface water waves
propagating on a depth-varying current with a non-uniform vorticity distribution. The
investigation is divided into two parts. The first concerns the ‘equilibrium’ conditions
in which the oscillatory wave motion and the current co-exist. Measurements of
the water-surface elevation, the water-particle kinematics, and the near-bed pressure
fluctuations are compared to a number of wave and wave–current solutions including
a nonlinear model capable of incorporating the vertical structure of the current profile.
These comparisons confirm that the near-surface vorticity leads to an important
modification of the dispersion equation, and thus affects the nature of the wave-induced
orbital motion over the entire water depth. However, the inclusion of vorticity-dependent
terms within the dispersion equation is not sufficient to define the combined
wave–current flow. The present results suggest that vorticity may lead to a significant
change in the water-surface profile. If a current is positively sheared, dU/dz > 0,
with negative vorticity at the water surface, as would be the case in a wind-driven
current, a wave propagating in the same direction as the current will experience
increased crest–trough asymmetry due to the vorticity distribution. With higher and
sharper wave crests there is a corresponding increase in both the maximum water-particle
accelerations and the maximum horizontal water-particle velocities. These
results are consistent with previous theoretical calculations involving uniform vorticity
distributions (Simmen & Saffman 1985 and Teles da Silva & Peregrine 1988).
The second part of the study addresses the ‘gradually varying’ problem in which
there are changes in the current, the wavelength and the wave height due to the
initial interaction between the wave and the current. These data show that there is
a large and non-uniform change in the current profile that is dependent upon both
the steepness of the waves and the vorticity distribution. Furthermore, comparisons
between the measured wave height change and a number of solutions based on the
conservation of wave action, confirm that the vorticity distribution plays a dominant
role. In the absence of a conservation equation for wave action appropriate for
nonlinear waves on a depth-varying current, an alternative approach based on the
conservation of total energy flux, first proposed by Longuet-Higgins & Stewart (1960),
is shown to be in good agreement with the measured data.
We compared reproductive characteristics of the dendrobatid frog Colostethus trinitatis at the Tamana cave in the Central Range hills and at five forest stream sites in the Northern Range hills of Trinidad. There were significant differences between sites in adult female body size, intraovarian clutch size (in absolute terms and relative to body size) and the size of tadpoles carried by male frogs. Clutch sizes ranged from 6 to 13 in the Northern Range samples and from 12 to 26 at Tamana. Adult male body size was similar at all sites. Tadpoles carried by male C. trinitatis at Tamana were significantly smaller (mean length 14.2 mm) than those carried by males at the five Northern range sites (mean length 16.4–16.7 mm). The smallest clutches and largest tadpoles were found at Mount St Benedict, where there was evidence of size-selective predation on tadpoles by fish. Tamana, where clutches were large and tadpoles small, differed from the Northern Range sites in terms of the physical environment (cave vs forest) and the abundance of invertebrates. We discuss possible ultimate and proximate causes of the differences in clutch size and tadpole size, particularly size-selective predation and availability of food.
The efficiency of visual selection in a glasshouse of 1600 seedlings compared with visual selection in the field of the same clones is examined. Also the amount of agreement in assessment between four different potato breeders screening the same clones is investigated. Seedlings were grown from true seed in four-inch pots in a glasshouse and all the clones which produced tubers were grown in the field the following year. Clones which produced more than one tuber from a seedling were grown at two locations in the first clonal year. One of the sites used in the first clonal year is normally used for potato yield trials (i.e. a ware site) and the other is normally used for the production of healthy seed tubers (i.e. a seed site). In all three environments, the tubers produced from each plant were assessed by four breeders independently on a 1–9 scale of increasing attractiveness.
From the data it was found that the repeatability of assessment between the glasshouse and the first clonal year was low in that the correlation between the average preference score of the four breeders in the glasshouse and each of the two first clonal year sites accounted for only 8·24 and 6·84% of the total variation. Many clones which had low scores in the glasshouse were subsequently given high scores in the first clonal year. It was therefore concluded that selection of seedlings was not very efficient. Although, in general, the weight of the tuber that was planted greatly influenced whether a clone was selected in the first clonal year, a large number of clones which produced only small tubers in the glasshouse were subsequently selected in the first clonal year.
Within each environment the four breeders were either all selecting, or all rejecting, a much higher proportion of clones than would be expected if selection had been made completely at random. The breeders were in most agreement when assessing clones at the ‘ware’ site, and in most disagreement when assessing them grown in the glasshouse from true seed. Therefore the poor efficiency of selection of seedlings grown in the glasshouse was not, in the main, a result of a high error variance in visual assessment but rather due to poor association between the performance of seedlings and first clonal year plants.