182 research outputs found
Targeted colonic release formulations of mesalazine - A clinical pharmaco-scintigraphic proof-of-concept study in healthy subjects and patients with mildly active ulcerative colitis.
Colonic targeting of orally applied therapeutic drugs remains a challenge. Tablet coatings relying on gastrointestinal pH and colonic bacterial enzymes as triggers in association with an inner alkaline layer are expected to improve targeting efficiency. Mesalazine release from three differently coated tablets labelled with 1 MBq 153Sm was characterised in a single centre, open-label, parallel group study in nineteen healthy subjects and seven patients with mildly active ulcerative colitis. Two semi-organic and one aqueous-based outer coating with different ratios of enteric polymer and resistant starch were tested. All coatings showed comparable release lagtimes in biorelevant dissolution media and were not affected by neutron-activation of the samarium tracer. Mesalazine pharmacokinetics and gamma scintigraphy were used to characterise drug release, anatomical site of tablet disintegration and gastrointestinal transit. Initial tablet disintegration occurred at the ileo-caecal junction or beyond in 92% of the subjects Time to initial tablet disintegration was inversely correlated with maximal plasma concentrations and systemic mesalazine exposure. Although high inter-subject variability precluded detection of differences between solvent types and different enteric polymer to polysaccharide ratios, the dual pH and enzymatic triggered release system in combination with an inner alkaline layer promoted mesalazine release at the target site with high accuracy
Water uptake patterns of pea and barley responded to drought but not to cropping systems
Agricultural production is under threat of water scarcity due to increasingly frequent and severe drought events under climate change. Whether a change in cropping systems can be used as an effective adaptation strategy against drought is still unclear. We investigated how plant water uptake patterns of a field-grown pea–barley (Pisum sativum L. and Hordeum vulgare L.) mixture, an important fodder intercrop, responded to experimental drought under four cropping systems, i.e. organic intensive tillage, conventional intensive tillage, conventional no tillage, and organic reduced tillage. Drought was simulated after crop establishment using rain shelters. Proportional contributions to plant water uptake from different soil layers were estimated based on stable water isotopes using Bayesian mixing models. Pea plants always took up proportionally more water from shallower depths than barley plants.Water uptake patterns of neither species were affected by cropping systems. Both species showed similar responses to the drought simulation and increased their proportional water uptake from the shallow soil layer (0–20 cm) in all cropping systems. Our results highlight the impact of drought on plant water uptake patterns for two important crop species and suggest that cropping systems might not be as successful as adaptation strategies against drought as previously thought
Severe drought rather than cropping system determines litter decomposition in arable systems
"Litter decomposition is a fundamental process in soil carbon dynamics and nutrient turnover. However, litter decomposition in arable systems remains poorly explored, and it is unclear whether different management practices, such as organic farming, conservation agriculture can mitigate drought effects on litter decomposition.
Thus, we examined the effects of a severe experimental drought on litter decomposition in four cropping systems, i.e., organic vs. conventional farming, each with two levels of tillage (intensive vs. conservation tillage) in Switzerland. We incubated two types of standard litter (tea bags), i.e., high-quality green tea with a low C:N ratio and low-quality rooibos tea with a high C:N ratio. We assessed litter decomposition during the simulated drought and in the post-drought period during three years in three different crops, i.e., pea-barley, maize, and winter wheat. Subsequently, we assessed whether decomposition in the four cropping systems differed in its resistance and resilience to drought.
Drought had a major impact on litter decomposition and suppressed decomposition to a similar extent in all cropping systems. Both drought resistance and resilience of decomposition were largely independent of cropping systems. Drought more strongly reduced decomposition of the high-quality litter compared to the low-quality litter during drought conditions regarding the absolute change in mass remaining (12.3% vs. 6.5 %, respectively). However, the decomposition of high-quality litter showed a higher resilience, i.e., high-quality approached undisturbed decomposition levels faster than low-quality litter after drought. Soil nitrate availability was also strongly reduced by drought (by 32–86 %), indicating the strong reduction in nutrient availability and, most likely, microbial activity due to water shortage. In summary, our study suggests that severe drought has a much stronger impact on decomposition than cropping system indicating that it might not be possible to maintain decomposition under drought by the cropping system approaches we studied. Nevertheless, management options that improve litter quality, such as the use of legume crops with high N concentrations, may help to enhance the resilience of litter decomposition in drought-stressed crop fields.
Limited capability of organic farming and conservation tillage to enhance agroecosystem resilience to severe drought
CONTEXT: Climate change increasingly threatens food security, particularly through prolonged phases of drought. It is therefore important to evaluate and develop arable cropping systems with an enhanced capability to withstand severe drought events to ensure food production. However, it is still poorly understood whether specific management strategies, in particular organic farming and conservation tillage that are thought to be more resilient to drought, can enhance the ability of agroecosystem to withstand drought.
OBJECTIVE: The main objective of this study was, therefore, to test the ability of organic farming and conservation tillage practices to withstand drought within expected boundaries of climate scenarios for the end of the century.
METHODS: This study summarizes the effects of drought (both natural and experimental) on the productivity of three arable crops (maize, pea-barley mixture and winter wheat) assessed in three consecutive years in a longterm cropping system field experiment. We tested whether four relevant cropping systems (i.e., conventional and organic with and without soil conservation tillage) differ in their ability to reduce the impact of drought on plant yield and crop performance. We studied conditions of moderate natural drought (summer 2018) and severe experimental droughts using rainout shelters (3 years) after 8 years of contrasting field management.
RESULTS AND CONCLUSIONS: We found pronounced and consistent yield reductions due to experimental drought events for all cropping systems (34% for maize, 23% for pea-barley, and 17% for winter wheat). Drought induced yield reductions were largely similar across the four cropping systems, suggesting very limited capacity of any cropping system to buffer severe drought. Yet, there was an obvious but insignificant trend in maize in 2018 where under moderate and experimental drought conservation tillage resulted in a higher on-average yield compared to the plowed systems. Furthermore, drought resulted in lower nitrogen (N) uptake by the crops and a positive N budget, which could result in higher N losses after a drought period.
SIGNIFICANCE: This study demonstrates that drought has consistent and adverse effects on crop productivity under conventional, organic and soil conservation arable cropping. It further demonstrates that it is difficult to find effective adaptation strategies for arable systems under realistic future scenarios and underlines the need to combine all available practices, from soil management to crop and cultivar choice, to mitigate drought impacts on crop productivity
Können ökologische und bodenschonende Ackerbausysteme Dürreperioden besser überstehen?
Diese Studie fasst die Auswirkungen simulierte Dürren auf die Produktivität von drei verschiedenen Ackerkulturen zusammen, die in drei aufeinanderfolgenden Jahren für insgesamt vier Erntejahrkombinationen in einem Langzeit-Feldexperiment untersucht wurden
Assessment of explanatory models of mental illness: effects of patient and interviewer characteristics
Background: Explanatory models (EMs) refer to patients’ causal attributions of illness and have been shown to affect treatment preference and outcome. Reliable and valid assessment of EMs may be hindered by interviewer and respondent disparities on certain demographic characteristics, such as ethnicity. The present study examined (a) whether ethnic minority patients reported different EMs to ethnically similar interviewers in comparison with those with a different ethnicity, and (b) whether this effect was related to respondents’ social desirability, the perceived rapport with the interviewer and level of uncertainty toward their EMs. Methods: A total of 55 patients of Turkish and Moroccan origins with mood and anxiety disorders were randomly assigned to ethnically similar or dissimilar interviewers. EMs were assessed, using a semi-structured interview, across 11 different categories of causes. Results: Participants who were interviewed by an ethnically similar interviewer perceived interpersonal, victimization and religious/mystical causes as more important, whereas interviews by ethnically dissimilar interviewers generated higher scores on medical causes. These effects were not mediated by the perceived rapport with the interviewer, and social desirability had a modest impact on the results. Higher uncertainty among participants toward medical and religious/mystical causes seemed to be associated with greater adjustment in the report of these EMs. Conclusion: The findings have significant implications for interviewer selection in epidemiological research and clinical practice
Grassland Resistance and Resilience after Drought Depends on Management Intensity and Species Richness
The degree to which biodiversity may promote the stability of grasslands in the light of climatic variability, such as prolonged summer drought, has attracted considerable interest. Studies so far yielded inconsistent results and in addition, the effect of different grassland management practices on their response to drought remains an open question. We experimentally combined the manipulation of prolonged summer drought (sheltered vs. unsheltered sites), plant species loss (6 levels of 60 down to 1 species) and management intensity (4 levels varying in mowing frequency and amount of fertilizer application). Stability was measured as resistance and resilience of aboveground biomass production in grasslands against decreased summer precipitation, where resistance is the difference between drought treatments directly after drought induction and resilience is the difference between drought treatments in spring of the following year. We hypothesized that (i) management intensification amplifies biomass decrease under drought, (ii) resistance decreases with increasing species richness and with management intensification and (iii) resilience increases with increasing species richness and with management intensification
Good practice in health care for migrants: views and experiences of care professionals in 16 European countries
<p>Abstract</p> <p>Background</p> <p>Health services across Europe provide health care for migrant patients every day. However, little systematic research has explored the views and experiences of health care professionals in different European countries. The aim of this study was to assess the difficulties professionals experience in their service when providing such care and what they consider constitutes good practice to overcome these problems or limit their negative impact on the quality of care.</p> <p>Methods</p> <p>Structured interviews with open questions and case vignettes were conducted with health care professionals working in areas with high proportion of migrant populations in 16 countries. In each country, professionals in nine primary care practices, three accident and emergency hospital departments, and three community mental health services (total sample = 240) were interviewed about their views and experiences in providing care for migrant patients, i.e. from first generation immigrant populations. Answers were analysed using thematic content analysis.</p> <p>Results</p> <p>Eight types of problems and seven components of good practice were identified representing all statements in the interviews. The eight problems were: language barriers, difficulties in arranging care for migrants without health care coverage, social deprivation and traumatic experiences, lack of familiarity with the health care system, cultural differences, different understandings of illness and treatment, negative attitudes among staff and patients, and lack of access to medical history. The components of good practice to overcome these problems or limit their impact were: organisational flexibility with sufficient time and resources, good interpreting services, working with families and social services, cultural awareness of staff, educational programmes and information material for migrants, positive and stable relationships with staff, and clear guidelines on the care entitlements of different migrant groups. Problems and good care components were similar across the three types of services.</p> <p>Conclusions</p> <p>Health care professionals in different services experience similar difficulties when providing care to migrants. They also have relatively consistent views on what constitutes good practice. The degree to which these components already are part of routine practice varies. Implementing good practice requires sufficient resources and organisational flexibility, positive attitudes, training for staff and the provision of information.</p
The Synergistic Effect of Concomitant Schistosomiasis, Hookworm, and Trichuris Infections on Children's Anemia Burden
Polyparasitic infections have been recognized as the norm in many tropical developing countries, but the significance of this phenomenon for helminth-associated morbidities is largely unexplored. Earlier studies have suggested that multi-species, low-intensity parasitic infections were associated with higher odds of anemia among school-age children relative to their uninfected counterparts or those with one low-intensity infection. However, specific studies of the nature of interactions between helminth species in the mediation of helminth-associated morbidities are lacking. This study quantifies the extent to which polyparasitic infections have more than the sum of adverse effects associated with individual infections in the context of childhood anemia. This study found that the risk of anemia is amplified beyond the sum of risks for individual infections in children simultaneously exposed to 1) hookworm and schistosomiasis, and 2) hookworm and trichuris, and suggests that combined treatment for some geohelminth species and schistosomiasis could yield greater than additive benefits for the reduction of childhood anemia in helminth-endemic areas. However, more studies to understand the full range of interactions between parasitic species in their joint effects on helminth-associated morbidities will be necessary to better predict the impact of any future public health intervention
Climate simulations for 1880-2003 with GISS modelE
We carry out climate simulations for 1880-2003 with GISS modelE driven by ten
measured or estimated climate forcings. An ensemble of climate model runs is
carried out for each forcing acting individually and for all forcing mechanisms
acting together. We compare side-by-side simulated climate change for each
forcing, all forcings, observations, unforced variability among model ensemble
members, and, if available, observed variability. Discrepancies between
observations and simulations with all forcings are due to model deficiencies,
inaccurate or incomplete forcings, and imperfect observations. Although there
are notable discrepancies between model and observations, the fidelity is
sufficient to encourage use of the model for simulations of future climate
change. By using a fixed well-documented model and accurately defining the
1880-2003 forcings, we aim to provide a benchmark against which the effect of
improvements in the model, climate forcings, and observations can be tested.
Principal model deficiencies include unrealistically weak tropical El Nino-like
variability and a poor distribution of sea ice, with too much sea ice in the
Northern Hemisphere and too little in the Southern Hemisphere. The greatest
uncertainties in the forcings are the temporal and spatial variations of
anthropogenic aerosols and their indirect effects on clouds.Comment: 44 pages; 19 figures; Final text accepted by Climate Dynamic
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