A hierarchical model for the analysis of spatial rainfall extremes

In this article, we propose a spatial model for analyzing extreme rainfall values over the Triveneto region (Italy). We assess the existence of a long-term trend in the extremes. To integrate data coming from the different stations, we propose a hierarchical model. At the first level, for each monitoring station we model data by making use of a generalized extreme value distribution; at the second level, we combine results from the first stage by exploiting recent advances in modeling nonstationary spatial random fields.     

The Use of Mineral Oil in Potato Protection: Dynamics in the Plant and Effect on Potato Virus Y Spread

The focus of this study was to evaluate two mineral oils (Superior 70 and Vazyl-Y) in reducing the seasonal spread of Potato Virus Y (PVY). Three concentrations of oil (0, 5, and 10 L ha^?1 of Superior 70; 0, 7.5, and 15 L ha^?1 of Vazyl-Y) and three spray regimes for both oils (every 3–4, 7, and 10–11 days) were tested. Two weeks after top-kill, two tubers from each of 49 plants free of virus at emergence were harvested from treatment plots, sprouted, and tested for PVY with enzyme-linked immunosorbent assay (ELISA). Results revealed that in the case of Superior 70, PVY spread in mineral oil treated plots ranged from 2.1 to 12.2 %, while in the control plots it ranged from 20.4 to 37.7 % across three cultivars. In the case of Vazyl-Y, PVY spread in mineral oil treated plots ranged from 2.1 to 26.5 %, while in the control plots it ranged from 49.9 to 85.7 % across three cultivars. These data show that there was a significant reduction in PVY due to spray of mineral oils. In addition, mineral oil was quantified in plants from the Superior 70 treated and the control plots to understand the dynamics of mineral oil during the season. While there was little to no oil measured in the leaves at the early stages of plant growth, a considerable amount of mineral oil was detected close to plant maturity. A basic model of the concentration of oil in the treated foliage was formulated to confirm our understanding of the factors at play. The model could explain from 50 to 90 % of the variation in oil content observed in the field. Plant growth and size are important factors affecting oil content in mineral oil treated foliage.     

Latent Process Modelling of Threshold Exceedances in Hourly Rainfall Series

Two features are often observed in analyses of both daily and hourly rainfall series. One is the tendency for the strength of temporal dependence to decrease when looking at the series above increasing thresholds. The other is the empirical evidence for rainfall extremes to approach independence at high enough levels. To account for these features, Bortot and Gaetan (Scand J Stat 41:606–621, 2014) focus on rainfall exceedances above a fixed high threshold and model their dynamics through a hierarchical approach that allows for changes in the temporal dependence properties when moving further into the right tail. It is found that this modelling procedure performs generally well in analyses of daily rainfalls, but has some inherent theoretical limitations that affect its goodness of fit in the context of hourly data. In order to overcome this drawback, we develop here a modification of the Bortot and Gaetan model derived from a copula-type technique. Application of both model versions to rainfall series recorded in Camborne, England, shows that they provide similar results when studying daily data, but in the analysis of hourly data the modified version is superior.     

Electrofishing in streams of low water conductivity but high biodiversity value: Challenges,limits and perspectives

Electrofishing in streams of low water conductivity has technical limitations leading to the widespread use of poison fishing. In theory, provided a high enough voltage gradient can be created in water, electrofishing should be possible in all but the lowest of conductivities (<10 µS/cm). Using custom‐made equipment delivering up to 1,500 V DC, tests were carried out in French Guiana on 27 streams with water conductivity as low as 16 µS/cm. Approximately 5,800 fish of 93 species were captured, with an electrofishing mortality rate of 1.83%. Poison treatments were used within enclosed sections to assess how efficient multiple pass electrofishing removal is when assessing species richness and population number. The Chao II estimator on 2 electrofishing passes gave the best results for species richness, but rare species can elude electrofishing. Estimates of total fish abundance (i.e. all species pooled) were possible with the use of depletion models. Capture efficiencies by species were highly biased, however, and abundance could be underestimated for the most difficult species to catch. These results show that with the right equipment and settings, electrofishing can be an efficient alternative to poison fishing surveys in small tropical streams of low water conductivity but high biodiversity value.     

THE 4C APPROACH AS A WAY TO UNDERSTAND SPECIES INTERACTIONS DETERMINING INTERCROPPING PRODUCTIVITY

● The 4C approach considers intercropping performances as the result of joint 4C effects. ● Partial land equivalent ratios indicate which effect(s) are the major one(s). ● A major effect of complementarity is related to a better capture of abiotic resources. Modern agriculture needs to develop transition pathways toward agroecological, resilient and sustainable farming systems. One key pathway for such agroecological intensification is the diversification of cropping systems using intercropping and notably cereal-grain legume mixtures. Such mixtures or intercrops have the potential to increase and stabilize yields and improve cereal grain protein concentration in comparison to sole crops. Species mixtures are complex and the 4C approach is both a pedagogical and scientific way to represent the combination of four joint effects of Competition, Complementarity, Cooperation, and Compensation as processes or effects occurring simultaneously and dynamically between species over the whole cropping cycle. Competition is when plants have fairly similar requirements for abiotic resources in space and time, the result of all processes that occur when one species has a greater ability to use limiting resources (e.g., nutrients, water, space, light) than others. Complementarity is when plants grown together have different requirements for abiotic resources in space, time or form. Cooperation is when the modification of the environment by one species is beneficial to the other(s). Compensation is when the failure of one species is compensated by the other(s) because they differ in their sensitivity to abiotic stress. The 4C approach allows to assess the performance of arable intercropping versus classical sole cropping through understanding the use of abiotic resources.     

Host genotype and amoxicillin administration affect the incidence of diarrhoea and faecal microbiota of weaned piglets during a natural multiresistant ETEC infection

Enterotoxigenic Escherichia coli (ETEC) is the aetiological agent of postweaning diarrhoea (PWD) in piglets. The SNPs located on the Mucine 4 (MUC4) and Fucosyltransferase 1 (FUT1) genes have been associated with the susceptibility to ETEC F4 and ETEC F18, respectively. The interplay between the MUC4 and FUT1 genotypes to ETEC infection and the use of amoxicillin in modifying the intestinal microbiota during a natural infection by multiresistant ETEC strains have never been investigated. The aim of this study was to evaluate the effects of the MUC4 and FUT1 genotypes and the administration of amoxicillin through different routes on the presence of diarrhoea and the faecal microbiota composition in piglets naturally infected with ETEC. Seventy-one piglets were divided into three groups: two groups differing by amoxicillin administration routes—parenteral (P) or oral (O) and a control group without antibiotics (C). Faecal scores, body weight, presence of ETEC F4 and F18 were investigated 4 days after the arrival in the facility (T0), at the end of the amoxicillin administration (T1) and after the withdrawal period (T2). The faecal bacteria composition was assessed by sequencing the 16S rRNA gene. We described that MUC4 and FUT1 genotypes were associated with the presence of ETEC F4 and ETEC F18. The faecal microbiota was influenced by the MUC4 genotypes at T0. We found the oral administration to be associated with the presence of diarrhoea at T1 and T2. Furthermore, the exposure to amoxicillin resulted in significant alterations of the faecal microbiota. Overall, MUC4 and FUT1 were confirmed as genetic markers for the susceptibility to ETEC infections in pigs. Moreover, our data highlight that group amoxicillin treatment may produce adverse outcomes on pig health in course of multiresistant ETEC infection. Therefore, alternative control measures able to maintain a healthy faecal microbiota in weaners are recommended.     

Epidemiology. DNA identifications after the 9/11 World Trade Center attack

The attack on the World Trade Center on 9/11/2001 challenged current approaches to forensic DNA typing methods. The large number of victims and the extreme thermal and physical conditions of the site necessitated special approaches to the DNA-based identification. Because of these and many additional challenges, new procedures were created or modified from routine forensic protocols. This effort facilitated the identification of 1594 of the 2749 victims. In this Policy Forum, the authors, who were were members of the World Trade Center Kinship and Data Analysis Panel, review the lessons of the attack response from the perspective of DNA forensic identification and suggest policies and procedures for future mass disasters or large-scale terrorist attacks.     

Identification and Characterization of a New Type III Polyketide Synthase from a Marine Yeast,Naganishia uzbekistanensis

A putative Type III Polyketide synthase (PKSIII) encoding gene was identified from a marine yeast, Naganishia uzbekistanensis strain Mo29 (UBOCC-A-208024) (formerly named as Cryptococcus sp.) isolated from deep-sea hydrothermal vents. This gene is part of a distinct phylogenetic branch compared to all known terrestrial fungal sequences. This new gene encodes a C-terminus extension of 74 amino acids compared to other known PKSIII proteins like Neurospora crassa. Full-length and reduced versions of this PKSIII were successfully cloned and overexpressed in a bacterial host, Escherichia coli BL21 (DE3). Both proteins showed the same activity, suggesting that additional amino acid residues at the C-terminus are probably not required for biochemical functions. We demonstrated by LC-ESI-MS/MS that these two recombinant PKSIII proteins could only produce tri- and tetraketide pyrones and alkylresorcinols using only long fatty acid chain from C8 to C16 acyl-CoAs as starter units, in presence of malonyl-CoA. In addition, we showed that some of these molecules exhibit cytotoxic activities against several cancer cell lines.