68 research outputs found
Detectable gravitational waves from very strong phase transitions in the general NMSSM
We study the general NMSSM with an emphasis on the parameter regions with a very strong first-order electroweak phase transition (EWPT). In the presence of heavy fields coupled to the Higgs sector, the analysis can be problematic due to the existence of sizable radiative corrections. In this paper we propose a subtraction scheme that helps to circumvent this problem. For simplicity we focus on a parameter region that is by construction hidden from the current collider searches. The analysis proves that (at least) in the identified parameter region the EWPT can be very strong and striking gravitational wave signals can be produced. The corresponding gravitational stochastic background can potentially be detected at the planned space-based gravitational wave observatory eLISA, depending on the specific experiment design that will be approved
Secular trends in stature of late 20th century white South Africans and two European populations
During the 20th century a general positive secular trend for stature is observed in developed countries around the world while shorter statures, often associated with a lack of a positive secular trend, have mostly been observed in populations with lower SES. The purpose of this study was to compare secular changes in stature between 20th century South Africans of European descent and two European populations. The comparative samples include Dutch males with which there is an assumed genetic relationship, and Swiss males for which the genetic association is less clear. The sample comprised anthropometric stature data of white South Africans (17–62 years), Swiss and Dutch males (18–21 years) obtained from military conscripts with birth cohorts of 5 years from 1946 to 1995. The stature of white South African males did not increase at a significant rate compared to those observed in Swiss and Dutch males. South African and Dutch males were of similar height following World War II, but a considerable trend was observed only in the Dutch group. The Swiss group was initially shorter than the South Africans, but due to a positive secular trend their average stature is on a par with that of South Africans in the most recent cohort. The lack of a significant positive secular trend in the South African group could suggest that factors such as gene flow and poor economic and social development in South Africa resulted in shorter statures in white South African groups than expected.The National Research Foundation (M. Steyn) and the Department of Anatomy at the University of Pretoria.http://www.elsevier.com/locate/jchb2018-12-30hj2018Anatom
Heat transfer during impact
The amount of heat transferred by conduction during the impact of a spherical particle with a surface depends on the thermophysical and mechanical properties of the two colliding media. Other factors, such as the surface properties (e.g. roughness, contamination, stress state, radius of curvature) and the velocity and direction of the impact, also influence the heat transfer. The available theoretical treatment of the heat transfer is based on the Hertzian theory of elastic contact, where the two colliding media are treated as two elastic half-spaces. In this study experiments are performed to measure the amount of heat transfer during impact of metallic spherical particles with small metallic collectors embedded in low thermal conductivity substrates. Convective heat transfer has been eliminated by performing the experiment in a vacuum chamber. However, radiative heat transfer is present and an effort has been made to minimize it by using highly reflective surfaces. The experimental results show that the measured heat transferred per impact is higher than that predicted by the Hertzian theory of elastic impact. The plastic deformation induced in the collector due to the relatively high velocity of impact causes an increase in the contact area and the impact duration. We analyze the heat transfer during plastic impact and discuss the role of other non-ideal conditions such as the flexibility of the support and the obliqueness of the impact.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30036/1/0000404.pd
Non-AIDS defining cancers in the D:A:D Study-time trends and predictors of survival : a cohort study
BACKGROUND:Non-AIDS defining cancers (NADC) are an important cause of morbidity and mortality in HIV-positive individuals. Using data from a large international cohort of HIV-positive individuals, we described the incidence of NADC from 2004-2010, and described subsequent mortality and predictors of these.METHODS:Individuals were followed from 1st January 2004/enrolment in study, until the earliest of a new NADC, 1st February 2010, death or six months after the patient's last visit. Incidence rates were estimated for each year of follow-up, overall and stratified by gender, age and mode of HIV acquisition. Cumulative risk of mortality following NADC diagnosis was summarised using Kaplan-Meier methods, with follow-up for these analyses from the date of NADC diagnosis until the patient's death, 1st February 2010 or 6 months after the patient's last visit. Factors associated with mortality following NADC diagnosis were identified using multivariable Cox proportional hazards regression.RESULTS:Over 176,775 person-years (PY), 880 (2.1%) patients developed a new NADC (incidence: 4.98/1000PY [95% confidence interval 4.65, 5.31]). Over a third of these patients (327, 37.2%) had died by 1st February 2010. Time trends for lung cancer, anal cancer and Hodgkin's lymphoma were broadly consistent. Kaplan-Meier cumulative mortality estimates at 1, 3 and 5 years after NADC diagnosis were 28.2% [95% CI 25.1-31.2], 42.0% [38.2-45.8] and 47.3% [42.4-52.2], respectively. Significant predictors of poorer survival after diagnosis of NADC were lung cancer (compared to other cancer types), male gender, non-white ethnicity, and smoking status. Later year of diagnosis and higher CD4 count at NADC diagnosis were associated with improved survival. The incidence of NADC remained stable over the period 2004-2010 in this large observational cohort.CONCLUSIONS:The prognosis after diagnosis of NADC, in particular lung cancer and disseminated cancer, is poor but has improved somewhat over time. Modifiable risk factors, such as smoking and low CD4 counts, were associated with mortality following a diagnosis of NADC
A century of trends in adult human height
Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries
Rising rural body-mass index is the main driver of the global obesity epidemic in adults
Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)
Water column and grab sample palynofacies assemblages from the Rajang River delta, Sarawak, East Malaysia
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