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Birth weight and early growth have been associated with later blood pressure. However, not all studies consistently find a significant reduction in blood pressure with an increase in birth weight. In addition, the relative importance of birth weight and of other lifestyle and environmental factors is often overlooked and the association is rarely studied in adolescents. We investigated early life predictors, including birth weight, of adolescent blood pressure in the Gateshead Millennium Study (GMS). The GMS is a cohort of 1029 individuals born in 1999–2000 in Gateshead in Northern England. Throughout infancy and early childhood, detailed information were collected, including birth weight and measures of height and weight. Assessments of 491 returning participants at age 12 years included measures of body mass and blood pressure. Linear regression and path analysis were used to determine predictors and their relative importance on blood pressure. Birth weight was not directly associated with blood pressure at the age of 12. However, after adjustment for contemporaneous body mass index (BMI), an inverse association of standardized birth weight on systolic blood pressure was significant. The relative importance of birth weight on later systolic blood pressure was smaller than other contemporaneous body measures (height and BMI). There was no independent association of birth weight on blood pressure seen in this adolescent population. Contemporaneous body measures have an important role to play. Lifestyle factors that influence body mass or size, such as diet and physical activity, where interventions are directed at early prevention of hypertension should be targeted.
The current project seeks to integrate literatures on personality risk for antisocial behavior (ASB) by examining how callous–unemotional traits relate to (a) the development of disinhibited traits and (b) the association between disinhibited traits and ASB. In Study 1, using a nationally representative sample of youth (N > 7,000), we examined whether conduct problems and lack of guilt assessed during ages 4–10 years predicted levels of and changes in disinhibited traits over the course of adolescence, and moderated associations between these traits and ASB. High levels of childhood conduct problems were associated with higher levels of impulsivity, sensation seeking, and ASB in early adolescence, whereas lack of guilt was associated with lower levels of sensation seeking. Neither conduct problems nor lack of guilt significantly predicted changes in impulsivity or sensation seeking, and associations among changes in sensation seeking, impulsivity, and ASB were also consistent across levels of conduct problems and lack of guilt. In Study 2, using a cross-sectional sample of adolescents (N = 970), we tested whether callous–unemotional traits moderated associations between disinhibited traits and ASB. Consistent with the results of Study 1, associations between disinhibited personality and ASB were consistent across a continuous range of callous–unemotional traits.
Cortisol is the primary output of the hypothalamic–pituitary–adrenal (HPA) axis and is central to the biological stress response, with wide-ranging effects on psychiatric health. Despite well-studied biological pathways of glucocorticoid function, little attention has been paid to the role of genetic variation. Conventional salivary, urinary and serum measures are strongly influenced by diurnal variation and transient reactivity. Recently developed technology can be used to measure cortisol accumulation over several months in hair, thus indexing chronic HPA function.
In a socio-economically diverse sample of 1070 twins/multiples (ages 7.80–19.47 years) from the Texas Twin Project, we estimated effects of sex, age and socio-economic status (SES) on hair concentrations of cortisol and its inactive metabolite, cortisone, along with their interactions with genetic and environmental factors. This is the first genetic study of hair neuroendocrine concentrations and the largest twin study of neuroendocrine concentrations in any tissue type.
Glucocorticoid concentrations increased with age for females, but not males. Genetic factors accounted for approximately half of the variation in cortisol and cortisone. Shared environmental effects dissipated over adolescence. Higher SES was related to shallower increases in cortisol with age. SES was unrelated to cortisone, and did not significantly moderate genetic effects on either cortisol or cortisone.
Genetic factors account for sizable proportions of glucocorticoid variation across the entire age range examined, whereas shared environmental influences are modest, and only apparent at earlier ages. Chronic glucocorticoid output appears to be more consistently related to biological sex, age and genotype than to experiential factors that cluster within nuclear families.
The observation of 8B solar Neutrinos in the Kamiokande-II detector is presented. Based on 450 days of data in the time period of January 1987 through May 1988, the measured flux obtained with Ee ≥ 9.3 MeV was 0.46 ± 0.13 (stat) ± 0.08 (sys) of the value predicted by the standard solar model. The detector and analysis methods were improved since June 1988 and the background level has been decreased by a factor of about three since then.
After a little more than forty years of work related to the interplanetary plasma and the heliosphere the IAU's Commission 49 was formally discontinued in 2015. The commission started its work when the first spacecraft were launched to measure the solar wind in–situ away from Earth orbit, both inward and outward from 1 AU. It now hands over its activities to a new commission during an era of space research when Voyager 1 measures in–situ the parameters of the local interstellar medium at the edge of the heliosphere. The commission will be succeeded by C.E3 with a similar area of responsibility but with more focused specific tasks that the community intends to address during the coming several years. This report includes a short description of the motivation for this commission and of the historical context. It then describes work from 2012 to 2015 during the present solar cycle 24 that has been the weakest in the space era so far. It gave rise to a large number of studies on solar energetic particles and cosmic rays. Other studies addressed e.g. the variation of the solar wind structure and energetic particle fluxes on long time scales, the detection of dust in the solar wind and the Voyager measurements at the edge of the heliosphere. The research is based on measurements from spacecraft that are at present operational and motivated by the upcoming Solar Probe + and Solar Orbiter missions to explore the vicinity of the Sun. We also report here the progress on new and planned radio instruments and their importance for heliospheric studies. Contributors to this report are Carine Briand, Yoichiro Hanaoka, Eduard Kontar, David Lario, Ingrid Mann, John D. Richardson.
Our previous work identified deficits in interference processing and learning/memory in past suicide attempters who were currently depressed and medication-free. In this study, we extend this work to an independent sample studied at various stages of illness and treatment (mild symptoms, on average) to determine if these deficits in past suicide attempters are evident during a less severe clinical state.
A total of 80 individuals with a past history of major depression and suicide attempt were compared with 81 individuals with a history of major depression and no lifetime suicide attempts on a battery of neurocognitive measures assessing attention, memory, abstract/contingent learning, working memory, language fluency and impulse control.
Past attempters performed more poorly in attention, memory and working memory domains, but also in an estimate of pre-morbid intelligence. After correction for this estimate, tests that had previously distinguished past attempters – a computerized Stroop task and the Buschke Selective Reminding Test – remained significantly worse in attempters. In a secondary analysis, similar differences were found among those with the lowest levels of depression (Hamilton Depression Rating Scale score <10), suggesting that these deficits may be trait markers independent of current symptomatology.
Deficits in interference processing and learning/memory constitute an enduring defect in information processing that may contribute to poor adaptation, other higher-order cognitive impairments and risk for suicidal behavior.
It has been suggested that in addition to genetic factors, fetal and post-natal growth influence cognition in early adulthood. However, most studies have been in developed populations, so it is unclear if the same findings would be seen in other, less developed, settings, and have used testing tools not applicable to an Australia Aboriginal population. This study investigated the relationships between cognitive function in early adulthood and birth weight and contemporary height. Simple reaction time (SRT), choice reaction time (CRT) and working memory (WM) were assessed using the CogState battery. A significant association was seen between birth weight and SRT in early adulthood, but not with the other two cognitive measures. Urban dwellers had significantly shorter SRT and CRT than their remote counterparts. Contemporary body mass index and maternal age were associated with CRT. Only fetal growth restriction was associated with WM, with greater WM in those with restricted growth. No associations were seen with contemporary height. These results suggest that fetal growth may be more important than the factors influencing post-natal growth in terms of cognition in early adulthood in this population, but that the associations may be inconsistent between cognitive outcomes. Further research is required to identify whether similar associations are seen in other, similar, populations and to assess why differences in cognitive outcome measures are seen.
In light of increasing global protein prices and with the need to reduce environmental impact of contemporary systems of milk production, the current review seeks to assess the feasibility of reducing levels of dietary CP in dairy cow diets. At CP levels between 140 and 220 g/kg DM there is a strong positive relationship between CP concentration and dry matter intake (DMI). However, such effects are modest and reductions in DMI when dietary CP is below 180 g/kg DM can be at least partially offset by improving the digestibility and amino acid profile of the undegradable protein (UDP) component of the diet or by increasing rumen fermentable energy. Level and balance of intestinally absorbable amino acids, in particular methionine and lysine, may become limiting at lower CP concentrations. In general the amino acid composition of microbial protein is superior to that of UDP, so that dietary strategies that aim to promote microbial protein synthesis in the rumen may go some way to correcting for amino acid imbalances in low CP diets. For example, reducing the level of NDF, while increasing the proportion of starch, can lead to improvements in nitrogen (N) utilisation as great as that achieved by reducing dietary CP to below 150 g/kg. A systematic review and meta-analysis of responses to rumen protected forms of methionine and lysine was conducted for early/mid lactation cows fed diets containing ⩽150 g CP/kg DM. This analysis revealed a small but significant (P=0.002) increase in milk protein yield when cows were supplemented with these rumen protected amino acids. Variation in milk and milk protein yield responses between studies was not random but due to differences in diet composition between studies. Cows fed low CP diets can respond to supplemental methionine and lysine so long as DMI is not limiting, metabolisable protein (MP) is not grossly deficient and other amino acids such as histidine and leucine do not become rate limiting. Whereas excess dietary protein can impair reproduction and can contribute to lameness, there is no evidence to indicate that reducing dietary CP levels to around 140 to 150 g CP/kg DM will have any detrimental effect on either cow fertility or health. Contemporary models that estimate MP requirements of dairy cows may require refinement and further validation in order to predict responses with low CP diets.
The effects of small concentrations of metallic impurities have been studied in conjunction with the formation of titanium disilicide. We report that, by introducing small quantities of a refractory metal such as molybdenum or tungsten at or near the titanium/silicon interface, the temperature required to form the C54 phase TiSi2 can be reduced by as much as 100°C. Furthermore, the resulting C54-TiSi2 film exhibits small (∼ 0.2μm) grain size and improved thermal stability. This discovery has the potential to reduce the complexity and cost associated with forming low resistivity TiSi2 on submicron structures and to significantly improve the titanium silicide process window for future sub-half-micron VLSI applications.
We demonstrate that the addition of a molybdenum interlayer between titanium and silicon enhances the formation of C54 TiSi2, without bypassing the formation of the C49 TiSi2 phase. In situ x-ray diffraction analysis during rapid thermal annealing, at a rate of 3 °C/s, was used to study the phase formation sequence of TiSi2 starting from a blanket bilayer of Ti on Mo on a polycrystalline Si substrate. It was shown, as in the case without the Mo layer, that the C49 TiSi2 phase forms first, followed by the C54 TiSi2 phase. The results were similar for undoped or arsenic, boron, and phosphorous doped polycrystalline silicon substrates. The temperature range over which the C49 phase is stable is reduced, on average, by 80 °C. The lower end of the range (appearance of C49) is increased by approximately 60 °C and the upper end of the range (disappearance of C49) is decreased by about 20 0C. The orientation of the C49 phase differs in that both the C49(131) and C49(060) orientations are observed, compared to the case without the Mo layer where only the C49(131) orientation is observed.
A new generation of sensors based on biologically inspired whisking action will help determine the presence and location of solid objects and fluid vortices similar to mechanisms used by whisker bearing animals such as rats and seals. By using nanoindentation, we demonstrate that mechanical properties are essentially uniform by cross section, but vary longitudinally from the whisker base (a 3.9 GPa elastic modulus) to the tip (a 3.1 GPa elastic modulus). Several recent studies show propagation of high frequency information through whiskers that are tuned by their physical properties. In order to fully understand and model these properties, this study demonstrates a more complex whisker structure than previously assumed.
Nanoscratching on GaAs (001) by a pyramidal diamond tip (Berkovitch) indenter has been carried on under different loads, scratching velocities and directions. Plastic deformation and fractures induced by scratching have been investigated by atomic force microscopy (AFM), and by scanning and transmission electron microscopy (SEM and TEM, respectively). Surface images revealed radial and surface tensile cracks. Focused ion beam (FIB) milling of the contact area revealed median and shear fracture distribution in the volume. The different cracks were characterized for various scratching conditions in terms of their direction of propagation, extension and frequencies. Plastic deformations have been characterized by vertical displacement of material. No purely ductile zone was observed, GaAs deformation occurred by fractures and plastic strain. Their preponderances are discussed in terms of material properties.