395 research outputs found
Genetic regulation of glucoraphanin accumulation in BenefortĆ©Ā® broccoli
Diets rich in broccoli (Brassica oleracea var italica) have been associated with maintenance of cardiovascular health and reduction in risk of cancer. These health beneļ¬ts have been
attributed to glucoraphanin that speciļ¬cally accumulates in broccoli. The development of broccoli with enhanced concentrations of glucoraphanin may deliver greater health beneļ¬ts.
Three high-glucoraphanin F1 broccoli hybrids were developed in independent programmes through genome introgression from the wild species Brassica villosa. Glucoraphanin and other metabolites were quantiļ¬ed in experimental ļ¬eld trials. Global SNP analyses quantiļ¬ed the differential extent of B. villosa introgression
The high-glucoraphanin broccoli hybrids contained 2.5ā3 times the glucoraphanin content of standard hybrids due to enhanced sulphate assimilation and modiļ¬cations in sulphur partitioning between sulphur-containing metabolites. All of the high-glucoraphanin hybrids possessed an introgressed B. villosa segment which contained a B. villosa Myb28 allele. Myb28
expression was increased in all of the high-glucoraphanin hybrids. Two high-glucoraphanin hybrids have been commercialised as Beneforte broccoli.
The study illustrates the translation of research on glucosinolate genetics from Arabidopsis to broccoli, the use of wild Brassica species to develop cultivars with potential consumer beneļ¬ts, and the development of cultivars with contrasting concentrations of glucoraphanin for use in blinded human intervention studie
Superrevivals in the quantum dynamics of a particle confined in a finite square well potential
We examine the revival features in wave packet dynamics of a particle
confined in a finite square well potential. The possibility of tunneling
modifies the revival pattern as compared to an infinite square well potential.
We study the dependence of the revival times on the depth of the square well
and predict the existence of superrevivals. The nature of these superrevivals
is compared with similar features seen in the dynamics of wavepackets in an
anharmonic oscillator potential.Comment: 8 pages in Latex two-column format with 5 figures (eps). To appear in
Physical Review
Dissipative Chaos in Semiconductor Superlattices
We consider the motion of ballistic electrons in a miniband of a
semiconductor superlattice (SSL) under the influence of an external,
time-periodic electric field. We use the semi-classical balance-equation
approach which incorporates elastic and inelastic scattering (as dissipation)
and the self-consistent field generated by the electron motion. The coupling of
electrons in the miniband to the self-consistent field produces a cooperative
nonlinear oscillatory mode which, when interacting with the oscillatory
external field and the intrinsic Bloch-type oscillatory mode, can lead to
complicated dynamics, including dissipative chaos. For a range of values of the
dissipation parameters we determine the regions in the amplitude-frequency
plane of the external field in which chaos can occur. Our results suggest that
for terahertz external fields of the amplitudes achieved by present-day free
electron lasers, chaos may be observable in SSLs. We clarify the nature of this
novel nonlinear dynamics in the superlattice-external field system by exploring
analogies to the Dicke model of an ensemble of two-level atoms coupled with a
resonant cavity field and to Josephson junctions.Comment: 33 pages, 8 figure
The Panchromatic Hubble Andromeda Treasury II. Tracing the Inner M31 Halo with Blue Horizontal Branch Stars
We attempt to constrain the shape of M31's inner stellar halo by tracing the
surface density of blue horizontal branch (BHB) stars at galactocentric
distances ranging from 2 kpc to 35 kpc. Our measurements make use of resolved
stellar photometry from a section of the Panchromatic Hubble Andromeda Treasury
(PHAT) survey, supplemented by several archival Hubble Space Telescope
observations. We find that the ratio of BHB to red giant stars is relatively
constant outside of 10 kpc, suggesting that the BHB is as reliable a tracer of
the halo population as the red giant branch. In the inner halo, we do not
expect BHB stars to be produced by the high metallicity bulge and disk, making
BHB stars a good candidate to be a reliable tracer of the stellar halo to much
smaller galactocentric distances. If we assume a power-law profile r^(-\alpha)
for the 2-D projected surface density BHB distribution, we obtain a
high-quality fit with a 2-D power-law index of \alpha=2.6^{+0.3}_{-0.2} outside
of 3 kpc, which flattens to \alpha<1.2 inside of 3 kpc. This slope is
consistent with previous measurements but is anchored to a radial baseline that
extends much farther inward. Finally, assuming azimuthal symmetry and a
constant mass-to-light ratio, the best-fitting profile yields a total halo
stellar mass of 2.1^{+1.7}_{-0.4} x 10^9 M_sun. These properties are comparable
with both simulations of stellar halo formation formed by satellite disruption
alone, and with simulations that include some in situ formation of halo stars.Comment: 15 pages, 1 table, 5 figures, accepted for publication in Ap
Genotyping of Human Lice Suggests Multiple Emergences of Body Lice from Local Head Louse Populations
While being phenotypically and physiologically different, human head and body lice are indistinguishable based on mitochondrial and nuclear genes. As protein-coding genes are too conserved to provide significant genetic diversity, we performed strain-typing of a large collection of human head and body lice using variable intergenic spacer sequences. Ninety-seven human lice were classified into ninety-six genotypes based on four intergenic spacer sequences. Genotypic and phylogenetic analyses using these sequences suggested that human head and body lice are still indistinguishable. We hypothesized that the phenotypic and physiological differences between human head and body lice are controlled by very limited mutations. Under conditions of poor hygiene, head lice can propagate very quickly. Some of them will colonize clothing, producing a body louse variant (genetic or phenetic), which can lead to an epidemic. Lice collected in Rwanda and Burundi, where outbreaks of louse-borne diseases have been recently reported, are grouped tightly into a cluster and those collected from homeless people in France were also grouped into a cluster with lice collected in French non-homeless people. Our strain-typing approach based on highly variable intergenic spacers may be helpful to elucidate louse evolution and to survey louse-borne diseases
Hypoxia induces dilated cardiomyopathy in the chick embryo: mechanism, intervention, and long-term consequences
Background: Intrauterine growth restriction is associated with an increased future risk for developing cardiovascular diseases. Hypoxia in utero is a common clinical cause of fetal growth restriction. We have previously shown that chronic hypoxia alters cardiovascular development in chick embryos. The aim of this study was to further characterize cardiac disease in hypoxic chick embryos. Methods: Chick embryos were exposed to hypoxia and cardiac structure was examined by histological methods one day prior to hatching (E20) and at adulthood. Cardiac function was assessed in vivo by echocardiography and ex vivo by contractility measurements in isolated heart muscle bundles and isolated cardiomyocytes. Chick embryos were exposed to vascular endothelial growth factor (VEGF) and its scavenger soluble VEGF receptor-1 (sFlt-1) to investigate the potential role of this hypoxia-regulated cytokine. Principal Findings: Growth restricted hypoxic chick embryos showed cardiomyopathy as evidenced by left ventricular (LV) dilatation, reduced ventricular wall mass and increased apoptosis. Hypoxic hearts displayed pump dysfunction with decreased LV ejection fractions, accompanied by signs of diastolic dysfunction. Cardiomyopathy caused by hypoxia persisted into adulthood. Hypoxic embryonic hearts showed increases in VEGF expression. Systemic administration of rhVEGF165 to normoxic chick embryos resulted in LV dilatation and a dose-dependent loss of LV wall mass. Lowering VEGF levels in hypoxic embryonic chick hearts by systemic administration of sFlt-1 yielded an almost complete normalization of the phenotype. Conclusions/Significance: Our data show that hypoxia causes a decreased cardiac performance and cardiomyopathy in chick embryos, involving a significant VEGF-mediated component. This cardiomyopathy persists into adulthood
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015
SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factorsāthe summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57Ā·8% (95% CI 56Ā·6ā58Ā·8) of global deaths and 41Ā·2% (39Ā·8ā42Ā·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211Ā·8 million [192Ā·7 million to 231Ā·1 million] global DALYs), smoking (148Ā·6 million [134Ā·2 million to 163Ā·1 million]), high fasting plasma glucose (143Ā·1 million [125Ā·1 million to 163Ā·5 million]), high BMI (120Ā·1 million [83Ā·8 million to 158Ā·4 million]), childhood undernutrition (113Ā·3 million [103Ā·9 million to 123Ā·4 million]), ambient particulate matter (103Ā·1 million [90Ā·8 million to 115Ā·1 million]), high total cholesterol (88Ā·7 million [74Ā·6 million to 105Ā·7 million]), household air pollution (85Ā·6 million [66Ā·7 million to 106Ā·1 million]), alcohol use (85Ā·0 million [77Ā·2 million to 93Ā·0 million]), and diets high in sodium (83Ā·0 million [49Ā·3 million to 127Ā·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
Evolution in Australasian Mangrove Forests: Multilocus Phylogenetic Analysis of the Gerygone Warblers (Aves: Acanthizidae)
The mangrove forests of Australasia have many endemic bird species but their
evolution and radiation in those habitats has been little studied. One genus
with several mangrove specialist species is Gerygone
(Passeriformes: Acanthizidae). The phylogeny of the Acanthizidae is reasonably
well understood but limited taxon sampling for Gerygone has
constrained understanding of its evolution and historical biogeography in
mangroves. Here we report on a phylogenetic analysis of
Gerygone based on comprehensive taxon sampling and a
multilocus dataset of thirteen loci spread across the avian genome (eleven
nuclear and two mitochondrial loci). Since Gerygone includes
three species restricted to Australia's coastal mangrove forests, we
particularly sought to understand the biogeography of their evolution in that
ecosystem. Analyses of individual loci, as well as of a concatenated dataset
drawn from previous molecular studies indicates that the genus as currently
defined is not monophyletic, and that the Grey Gerygone (G.
cinerea) from New Guinea should be transferred to the genus
Acanthiza. The multilocus approach has permitted the
nuanced view of the group's evolution into mangrove ecosystems having
occurred on multiple occasions, in three non-overlapping time frames, most
likely first by the G. magnirostris lineage, and subsequently
followed by those of G. tenebrosa and G.
levigaster
Burden of injury along the development spectrum: Associations between the Socio-demographic Index and disability-adjusted life year estimates from the Global Burden of Disease Study 2017
Background: The epidemiological transition of non-communicable diseases replacing infectious diseases as the main contributors to disease burden has been well documented in global health literature. Less focus, however, has been given to the relationship between sociodemographic changes and injury. The aim of this study was to examine the association between disability-adjusted life years (DALYs) from injury for 195 countries and territories at different levels along the development spectrum between 1990 and 2017 based on the Global Burden of Disease (GBD) 2017 estimates. Methods: Injury mortality was estimated using the GBD mortality database, corrections for garbage coding and CODEm-the cause of death ensemble modelling tool. Morbidity estimation was based on surveys and inpatient and outpatient data sets for 30 cause-of-injury with 47 nature-of-injury categories each. The Socio-demographic Index (SDI) is a composite indicator that includes lagged income per capita, average educational attainment over age 15 years and total fertility rate. Results: For many causes of injury, age-standardised DALY rates declined with increasing SDI, although road injury, interpersonal violence and self-harm did not follow this pattern. Particularly for self-harm opposing patterns were observed in regions with similar SDI levels. For road injuries, this effect was less pronounced. Conclusions: The overall global pattern is that of declining injury burden with increasing SDI. However, not all injuries follow this pattern, which suggests multiple underlying mechanisms influencing injury DALYs. There is a need for a detailed understanding of these patterns to help to inform national and global efforts to address injury-related health outcomes across the development spectrum
Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990ā2015: a systematic analysis for the Global Burden of Disease Study 2015
Background Non-fatal outcomes of disease and injury increasingly detract from the ability of the world's population to live in full health, a trend largely attributable to an epidemiological transition in many countries from causes affecting children, to non-communicable diseases (NCDs) more common in adults. For the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015), we estimated the incidence, prevalence, and years lived with disability for diseases and injuries at the global, regional, and national scale over the period of 1990 to 2015. Methods We estimated incidence and prevalence by age, sex, cause, year, and geography with a wide range of updated and standardised analytical procedures. Improvements from GBD 2013 included the addition of new data sources, updates to literature reviews for 85 causes, and the identification and inclusion of additional studies published up to November, 2015, to expand the database used for estimation of non-fatal outcomes to 60ā900 unique data sources. Prevalence and incidence by cause and sequelae were determined with DisMod-MR 2.1, an improved version of the DisMod-MR Bayesian meta-regression tool first developed for GBD 2010 and GBD 2013. For some causes, we used alternative modelling strategies where the complexity of the disease was not suited to DisMod-MR 2.1 or where incidence and prevalence needed to be determined from other data. For GBD 2015 we created a summary indicator that combines measures of income per capita, educational attainment, and fertility (the Socio-demographic Index [SDI]) and used it to compare observed patterns of health loss to the expected pattern for countries or locations with similar SDI scores. Findings We generated 9Ā·3 billion estimates from the various combinations of prevalence, incidence, and YLDs for causes, sequelae, and impairments by age, sex, geography, and year. In 2015, two causes had acute incidences in excess of 1 billion: upper respiratory infections (17Ā·2 billion, 95% uncertainty interval [UI] 15Ā·4ā19Ā·2 billion) and diarrhoeal diseases (2Ā·39 billion, 2Ā·30ā2Ā·50 billion). Eight causes of chronic disease and injury each affected more than 10% of the world's population in 2015: permanent caries, tension-type headache, iron-deficiency anaemia, age-related and other hearing loss, migraine, genital herpes, refraction and accommodation disorders, and ascariasis. The impairment that affected the greatest number of people in 2015 was anaemia, with 2Ā·36 billion (2Ā·35ā2Ā·37 billion) individuals affected. The second and third leading impairments by number of individuals affected were hearing loss and vision loss, respectively. Between 2005 and 2015, there was little change in the leading causes of years lived with disability (YLDs) on a global basis. NCDs accounted for 18 of the leading 20 causes of age-standardised YLDs on a global scale. Where rates were decreasing, the rate of decrease for YLDs was slower than that of years of life lost (YLLs) for nearly every cause included in our analysis. For low SDI geographies, Group 1 causes typically accounted for 20ā30% of total disability, largely attributable to nutritional deficiencies, malaria, neglected tropical diseases, HIV/AIDS, and tuberculosis. Lower back and neck pain was the leading global cause of disability in 2015 in most countries. The leading cause was sense organ disorders in 22 countries in Asia and Africa and one in central Latin America; diabetes in four countries in Oceania; HIV/AIDS in three southern sub-Saharan African countries; collective violence and legal intervention in two north African and Middle Eastern countries; iron-deficiency anaemia in Somalia and Venezuela; depression in Uganda; onchoceriasis in Liberia; and other neglected tropical diseases in the Democratic Republic of the Congo. Interpretation Ageing of the world's population is increasing the number of people living with sequelae of diseases and injuries. Shifts in the epidemiological profile driven by socioeconomic change also contribute to the continued increase in years lived with disability (YLDs) as well as the rate of increase in YLDs. Despite limitations imposed by gaps in data availability and the variable quality of the data available, the standardised and comprehensive approach of the GBD study provides opportunities to examine broad trends, compare those trends between countries or subnational geographies, benchmark against locations at similar stages of development, and gauge the strength or weakness of the estimates available. Funding Bill & Melinda Gates Foundation
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