214 research outputs found
Inter- and intra-specific variation in accumulation of cadmium by peanut, soybean, and navybean
Production of summer grain legumes like peanut, soybean, and navybean is expanding into irrigated or high rainfall areas on more acid, lighter textured soils in coastal areas of north-eastern Australia. A history of intensive use of phosphatic fertilisers, combined with soil properties which generally enhance phytoavailability of cadmium (Cd), have produced concerns about the likely quality of grain legumes produced in these areas. This paper reports field and pot experiments which examine the effect of grain legume species and variety on Cd accumulation when grown across a range of soil types. Results clearly show that both peanut and soybean accumulate Cd in seeds at levels greater than the maximum permitted concentration (MPC, 0·05 mg Cd/kg) even on soils with relatively low total or available Cd concentrations ( soybean > navybean, with the differences between peanut and navybean apparently correlated with differences in total plant Cd uptake. Cadmium concentrations in plant tops always exceeded that in seeds or kernel, and the testa in peanut kernel was shown to contain Cd concentrations that were 50 times greater than that in the embryonic axis and cotyledons.
Significant (P < 0·05) variation in Cd content (at least 2-fold) was recorded among peanut varieties, with lesser variation evident among a limited sample of commercial navybean varieties. Comparison of results for 11 peanut varieties grown at each of 2 locations suggested strong genotype environment interactions determining kernel Cd concentration.
Highly significant (P < 0·01) linear relationships were established between soil Cd in the cultivated layer (0-20 cm; 0·1 M CaCl2 extraction) and seed Cd content in field-grown soybean. However, despite observations of an apparent relationship between soil Cd (CaCl2 extraction) and peanut kernel Cd in pot studies, relationships between soil Cd in the cultivated layer and kernel Cd could not be reproduced in field trials. Kernel Cd concentrations from field-grown peanut plants were generally higher than those from pot trials, despite using soil collected from the cultivated layer (0-20 cm) of the field site for the potting medium. The presence of significant levels of Cd to approximately 60 cm in the soil profile and a general decline in pHw with depth suggest the lack of correlation between soil test Cd in the top 20 cm and kernel Cd in field-grown plants may be at least partly due to Cd uptake from deeper soil layers
Localization and Coherence in Nonintegrable Systems
We study the irreversible dynamics of nonlinear, nonintegrable Hamiltonian
oscillator chains approaching their statistical asympotic states. In systems
constrained by more than one conserved quantity, the partitioning of the
conserved quantities leads naturally to localized and coherent structures. If
the phase space is compact, the final equilibrium state is governed by entropy
maximization and the final coherent structures are stable lumps. In systems
where the phase space is not compact, the coherent structures can be collapses
represented in phase space by a heteroclinic connection to infinity.Comment: 41 pages, 15 figure
Recovery from PTSD following Hurricane Katrina
Background: We examined patterns and correlates of speed of recovery of estimated posttraumatic stress disorder (PTSD) among people who developed PTSD in the wake of Hurricane Katrina. Method: A probability sample of prehurricane residents of areas affected by Hurricane Katrina was administered a telephone survey 7–19 months following the hurricane and again 24–27 months posthurricane. The baseline survey assessed PTSD using a validated screening scale and assessed a number of hypothesized predictors of PTSD recovery that included sociodemographics, prehurricane history of psychopathology, hurricane‐related stressors, social support, and social competence. Exposure to posthurricane stressors and course of estimated PTSD were assessed in a follow‐up interview. Results: An estimated 17.1% of respondents had a history of estimated hurricane‐related PTSD at baseline and 29.2% by the follow‐up survey. Of the respondents who developed estimated hurricane‐related PTSD, 39.0% recovered by the time of the follow‐up survey with a mean duration of 16.5 months. Predictors of slow recovery included exposure to a life‐threatening situation, hurricane‐related housing adversity, and high income. Other sociodemographics, history of psychopathology, social support, social competence, and posthurricane stressors were unrelated to recovery from estimated PTSD. Conclusions: The majority of adults who developed estimated PTSD after Hurricane Katrina did not recover within 18–27 months. Delayed onset was common. Findings document the importance of initial trauma exposure severity in predicting course of illness and suggest that pre‐ and posttrauma factors typically associated with course of estimated PTSD did not influence recovery following Hurricane Katrina. Depression and Anxiety, 2011. © 2011 Wiley‐Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87167/1/20790_ftp.pd
Targeted disruption of fibulin-4 abolishes elastogenesis and causes perinatal lethality in mice
Elastic fibers provide tissues with elasticity which is critical to the function of arteries, lungs, skin, and other dynamic organs. Loss of elasticity is a major contributing factor in aging and diseases. However, the mechanism of elastic fiber development and assembly is poorly understood. Here, we show that lack of fibulin-4, an extracellular matrix molecule, abolishes elastogenesis. fibulin-4(−/−) mice generated by gene targeting exhibited severe lung and vascular defects including emphysema, artery tortuosity, irregularity, aneurysm, rupture, and resulting hemorrhages. All the homozygous mice died perinatally. The earliest abnormality noted was a uniformly narrowing of the descending aorta in fibulin-4(−/−) embryos at embryonic day 12.5 (E12.5). Aorta tortuosity and irregularity became noticeable at E15.5. Histological analysis demonstrated that fibulin-4(−/−) mice do not develop intact elastic fibers but contain irregular elastin aggregates. Electron microscopy revealed that the elastin aggregates are highly unusual in that they contain evenly distributed rod-like filaments, in contrast to the amorphous appearance of normal elastic fibers. Desmosine analysis indicated that elastin cross-links in fibulin-4(−/−) tissues were largely diminished. However, expression of tropoelastin or lysyl oxidase mRNA was unaffected in fibulin-4(−/−) mice. In addition, fibulin-4 strongly interacts with tropoelastin and colocalizes with elastic fibers in culture. These results demonstrate that fibulin-4 plays an irreplaceable role in elastogenesis
Incorporating patient partner scores into high stakes assessment : an observational study into opinions and attitudes
Peer reviewedPublisher PD
Development of lifetime comorbidity in the world health organization world mental health surveys
CONTEXT: Although numerous studies have examined the role of latent variables in the structure of comorbidity among mental disorders, none has examined their role in the development of comorbidity. OBJECTIVE: To study the role of latent variables in the development of comorbidity among 18 lifetime DSM-IV disorders in the World Health Organization World Mental Health Surveys. DESIGN: Nationally or regionally representative community surveys. SETTING: Fourteen countries. PARTICIPANTS: A total of 21 229 survey respondents. MAIN OUTCOME MEASURES: First onset of 18 lifetime DSM-IV anxiety, mood, behavior, and substance disorders assessed retrospectively in the World Health Organization Composite International Diagnostic Interview. RESULTS: Separate internalizing (anxiety and mood disorders) and externalizing (behavior and substance disorders) factors were found in exploratory factor analysis of lifetime disorders. Consistently significant positive time-lagged associations were found in survival analyses for virtually all temporally primary lifetime disorders predicting subsequent onset of other disorders. Within-domain (ie, internalizing or externalizing) associations were generally stronger than between-domain associations. Most time-lagged associations were explained by a model that assumed the existence of mediating latent internalizing and externalizing variables. Specific phobia and obsessive-compulsive disorder (internalizing) and hyperactivity and oppositional defiant disorders (externalizing) were the most important predictors. A small number of residual associations remained significant after controlling the latent variables. CONCLUSIONS: The good fit of the latent variable model suggests that common causal pathways account for most of the comorbidity among the disorders considered herein. These common pathways should be the focus of future research on the development of comorbidity, although several important pairwise associations that cannot be accounted for by latent variables also exist that warrant further focused study
Improving the effectiveness of Ugandan water user committees
This article outlines issues affecting the functionality of Ugandan water user committees responsible for managing communal water and sanitation (WASH) services. Research undertaken demonstrated that their effectiveness is compromised by poor understanding of their rights and responsibilities by stakeholders within and outside the committees. Following the research, a handbook was produced that explained the rights and responsibilities in a form that is accessible to all community members. Preliminary feedback from committees that have used the handbook suggests that it has the potential to improve the functionality of the water user committees, thereby helping to improve the local management of WASH services in Uganda
Erythroid-Specific Transcriptional Changes in PBMCs from Pulmonary Hypertension Patients
Gene expression profiling of peripheral blood mononuclear cells (PBMCs) is a powerful tool for the identification of surrogate markers involved in disease processes. The hypothesis tested in this study was that chronic exposure of PBMCs to a hypertensive environment in remodeled pulmonary vessels would be reflected by specific transcriptional changes in these cells.The transcript profiles of PBMCs from 30 idiopathic pulmonary arterial hypertension patients (IPAH), 19 patients with systemic sclerosis without pulmonary hypertension (SSc), 42 scleroderma-associated pulmonary arterial hypertensio patients (SSc-PAH), and 8 patients with SSc complicated by interstitial lung disease and pulmonary hypertension (SSc-PH-ILD) were compared to the gene expression profiles of PBMCs from 41 healthy individuals. Multiple gene expression signatures were identified which could distinguish various disease groups from controls. One of these signatures, specific for erythrocyte maturation, is enriched specifically in patients with PH. This association was validated in multiple published datasets. The erythropoiesis signature was strongly correlated with hemodynamic measures of increasing disease severity in IPAH patients. No significant correlation of the same type was noted for SSc-PAH patients, this despite a clear signature enrichment within this group overall. These findings suggest an association of the erythropoiesis signature in PBMCs from patients with PH with a variable presentation among different subtypes of disease.In PH, the expansion of immature red blood cell precursors may constitute a response to the increasingly hypoxic conditions prevalent in this syndrome. A correlation of this erythrocyte signature with more severe hypertension cases may provide an important biomarker of disease progression
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