Do colonization by dark septate endophytes and elevated temperature affect pathogenicity of oomycetes?

Phialocephala subalpina is one of the most frequent dark septate root endophytes in tree roots but its function in forest ecosystems is largely unknown. A full-factorial infection experiment was performed, using six P. subalpina isolates, two pathogenic oomycetes (Phytophthora plurivora [syn. Phytophthora citricola s.l.] and Elongisporangium undulatum [syn. Pythium undulatum]) and two temperature regimes (17.9 and 21.6 °C) to examine the ability of P. subalpina to protect Norway spruce seedlings against root pathogens. Seedling survival, disease intensity and seedling growth were affected by P. subalpina genotype, temperature and pathogen species. Some P. subalpina isolates effectively reduced mortality and disease intensity caused by the two pathogens. Elevated temperature adversely affected seedling growth but did not aggravate the effect of the pathogens. Elongisporangium undulatum but not P. plurivora significantly reduced plant growth. Colonization density of P. subalpina measured by quantitative PCR was not affected by temperature or the presence of the pathogens. In conclusion, P. subalpina confers an indirect benefit to its host and might therefore be tolerated in natural ecosystems, despite negative effects on plant health and plant growt

Microsatellite-Based Quantification Method to Estimate Biomass of Endophytic Phialocephala Species in Strain Mixtures

Fungi of the Phialocephala fortinii sensu lato-Acephala applanata species complex (PAC) are ubiquitous endophytic colonizers of tree roots in which they form genotypically diverse communities. Measurement of the colonization density of each of the fungal colonizers is a prerequisite to study the ecology of these communities. Up to now, there is no method readily available for the quantification of PAC strains co-colonizing the same root. The new DNA quantification method presented here is based on the amplification of microsatellites by competitive polymerase chain reaction (PCR). The method proved to be suitable to detect and quantify at least two strains within one single sample by the addition of a known amount of mycelium of a reference strain before DNA extraction. The method exploits the correlation between the reference/target ratio of light emitted during microsatellite detection (peak ratio) and the reference/target ratio of mycelial weights to determine the biomass of the target strain. Hence, calibration curves were obtained by linear regression of the peak ratios on the weight ratios for different mixtures of reference and target strains. The slopes of the calibration curves and the coefficients of determination were close to 1, indicating that peak ratios are good predictors of weight ratios. Estimates of fungal biomass in mycelial test mixtures of known composition laid within the 95% prediction interval and deviated on average by 16% (maximally 50%) from the true biomass. On average, 3-6% of the root biomass of Norway spruce seedlings consisted of mycelial biomass of either one of two inoculated PAC strains. Biomass estimates obtained by real-time quantitative PCR were correlated with the estimates obtained by the microsatellite-based method, but variation between the two estimates from the same root was high in some samples. The microsatellite-based DNA quantification method described here is currently the best method for strainwise estimation of endophytic biomass of PAC fungi in small root sample

Can Tanzania's adaptation measures prevent future maize yield decline? A simulation study from Singida region

Cereal crop production in sub-Saharan Africa has not achieved the much-needed increase in yields to foster economic development and food security. Maize yields in the region's semi-arid agroecosystems are constrained by highly variable rainfall, which may be worsened by climate change. Thus, the Tanzanian government has prioritized agriculture as an adaptation sector in its intended nationally determined contribution, and crop management adjustments as a key investment area in its Agricultural Sector Development Programme. In this study, we investigated how future changes in maize yields under different climate scenarios can be countered by regional adjusted crop management and cultivar adaptation strategies. A crop model was used to simulate maize yields in the Singida region of Tanzania for the baseline period 1980-2012 and under three future climate projections for 2020-2060 and 2061-2099. Adaptation strategies to improve yields were full irrigation, deficit irrigation, mulch and nitrogen addition and another cultivar. According to our model results, increase in temperature is the main driver of future maize yield decline. Increased respiration and phenological development were associated with lower maize yields of 16% in 2020-2060 and 20% in 2061-2099 compared to the 1980-2012 baseline. Surprisingly, none of the management strategies significantly improved yields; however, a different maize variety that was tested as an alternative coping strategy performed better. This study suggests that investment in accessibility of improved varieties and investigation of maize traits that have the potential to perform well in a warmer future are better suited for sustaining maize production in the semi-arid region than adjustments in crop management

Farm Production Diversity and Household Dietary Diversity: Panel Data Evidence From Rural Households in Tanzania

Evidence on whether diversifying farm production leads to improved household dietary diversity and nutrition remains inconclusive. Existing studies analyzing the link between production diversity and dietary diversity are mainly based on cross-sectional methods, which could be biased by omitted confounding factors. Using two waves of a panel household survey of 900 rural households in Tanzania, this paper examines the link between production diversity and dietary diversity, while minimizing potential confounding effects. We estimate four regression models with two different production diversity measures and two panel estimation methods—fixed effect (FE) and random effect (RE). In three out of the four models, production diversity is significantly and positively associated with the dietary diversity measure of the food consumption score. The production diversity indicator is represented by the total crop and livestock species count, as well as by counting only crop species. The total crop and livestock species count shows a significant positive association with dietary diversity across estimation methods while the positive association with crop species count is not significant in the FE method. Our results suggest that the selection of appropriate production diversity indicators tailored to the specific circumstances of the local agricultural system is likely one key factor in identifying a robust relationship between production diversity and dietary diversity

Farm Production Diversity and Household Dietary Diversity: Panel Data Evidence From Rural Households in Tanzania

Evidence on whether diversifying farm production leads to improved household dietary diversity and nutrition remains inconclusive. Existing studies analyzing the link between production diversity and dietary diversity are mainly based on cross-sectional methods, which could be biased by omitted confounding factors. Using two waves of a panel household survey of 900 rural households in Tanzania, this paper examines the link between production diversity and dietary diversity, while minimizing potential confounding effects. We estimate four regression models with two different production diversity measures and two panel estimation methods—fixed effect (FE) and random effect (RE). In three out of the four models, production diversity is significantly and positively associated with the dietary diversity measure of the food consumption score. The production diversity indicator is represented by the total crop and livestock species count, as well as by counting only crop species. The total crop and livestock species count shows a significant positive association with dietary diversity across estimation methods while the positive association with crop species count is not significant in the FE method. Our results suggest that the selection of appropriate production diversity indicators tailored to the specific circumstances of the local agricultural system is likely one key factor in identifying a robust relationship between production diversity and dietary diversity.Peer Reviewe

Stronger Food and Nutrition Security Impacts from More Intense Project Participation: Evidence from a Multi-Country Intervention Program

Rigorous experiments show that nutrition-sensitive intervention programs can contribute to improved food and nutrition security (FNS) of rural households in low-and middle-income countries. Targeted individuals may, however, choose to engage with the intervention package at different intensities. It is yet unclear to what extent individual participation in more interventions influences FNS outcomes. Positive links would justify efforts by development stakeholders to diversify intervention packages and enable, encourage, or incentivize beneficiaries to participate in many different interventions. Using cross-sectional data from 2733 households across seven countries, we first estimate effects of a multi-sectoral intervention program using probit regressions, propensity score matching, and inverse probability weighted regression adjustment. Over the course of the three-year program, beneficiaries joined 8.3 interventions, on average. We find that targeted households were 6–9 percent more likely to be food secure, and targeted women and children were 15–17 percent more likely to consume a nutrient-adequate diet. Our estimates show that, across three indicators of FNS, each additional intervention increased the probability of achieving positive outcomes by about 1 percent. We conclude that investments in diversified intervention programs can be justified by stronger FNS benefits. Development stakeholders could enable strong individual participation by reducing transaction and opportunity costs of participation.Peer Reviewe

Das Verfahren vor dem Berner Kindes- und Erwachsenenschutzgericht

In the canton of Bern, the Child and Adult Protection Court performs the tasks of the judicial complaints authority in child and adult protection matters. It forms part of the civil department of the higher court and is made up of senior judges as well as specialist judges. The proceedings before this specialized court are characterized by a pluralism of legal sources: a federal rump order in the Swiss Civil Code is given concrete form by a cantonal special procedural code, which in turn refers to the general administrative process of the canton of Bern. The present work systematically presents the proceedings before the child and adult protection court and is intended to serve as an orientation for those seeking justice, lawyers and members of the court on procedural issues

Electronic excitations induced by the impact of coinage metal ions and clusters on a rare gas matrix: neutralization and luminescence

Low energy collisions of atomic ions and cluster ions with rare gas covered metal substrates can lead to strong light emission which is element and size specific. Instead of a direct energy transfer into the electronic system of the cluster the observed emission originates from excitons trapped in the rare gas layer which carries the excitation energy. The nature of the processes involved in the neutralization and excitation of the neutral clusters electronic system are discussed. Strong analogies to thermoluminescence are found

Parasite DNA detection in water samples enhances crayfish plague monitoring in asymptomatic invasive populations

Invasive species can facilitate the spread of pathogens by first providing asymptomatic host reservoirs, and then driving disease outbreaks in native populations through pathogen spillover. An example of this are invasive crayfish species in Europe (Faxonius limosus, Pacifastacus leniusculus, Procambarus clarkii), which carry the deadly plague agent (Aphanomyces astaci). Effective disease management requires comprehensive monitoring, however, pathogen detection in carrier populations with low pathogen prevalence and intensities is challenging. We simultaneously collected and analysed crayfish tissue samples of invasive crayfish populations and water samples to compare A. astaci detection in different sample types using quantitative PCR. Combined, the two sampling methods revealed A. astaci presence with DNA concentrations above limit of detection (LOD; the lowest concentration which can be detected with reasonable certainty) in 13 of 23 invasive crayfish populations. In four additional sites, A. astaci DNA concentrations below LOD were found in water. In four populations only were A. astaci concentrations above LOD detected in both sample types and in three populations in concentrations above LOD in tissue but below LOD in water. The likely reason for these discrepancies is the low A. astaci prevalence and concentration in resistant invasive crayfish, which limit detection reliability. Consistency may be improved by timing surveys with seasonal periods of high A. astaci abundance and by increasing water sampling effort. Considering the ease of collecting eDNA samples, compared to crayfish tissue sampling, eDNA methods would facilitate frequent and comprehensive surveys. However, remaining uncertainties in eDNA-based detection reveal the relevance of combining monitoring tools to improve detection of invasive pathogens and their management

Collision-induced luminescence from the impact of ions and cluster ions on solid rare gases

Light emission during the collision of ions and cluster ions on a metal surface covered by rare gas matrices of variable thickness is reported. The light intensity as a function of distance from the metal surface follows the classical image dipole theory. The spectral signature of the light corresponds to the fluorescence of the neutral cluster species deposited as well as to fragments. The nature of the processes involved in this luminescence, in the neutralization and the excitation are discussed. A microscopic model for the mechanism is proposed: in this model rare gas excitons are produced in the collision process