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Switching Spectroscopy Piezoresponse Force Microscopy (SSPFM) stands out as a powerful method for probing ferroelectric properties within materials subjected to incremental polarization induced by an external electric field. However, the dense data processing linked to this technique is a critical factor influencing the quality of obtained results. Furthermore, meticulous exploration of various artifacts, such as electrostatics, which may considerably influence the signal, is a key factor in obtaining quantitative results. In this paper, we present a global methodology for SSPFM data processing, accessible in open-source with a user-friendly Python application called PySSPFM. A ferroelectric thin film sample of potassium sodium niobate has been probed to illustrate the different aspects of our methodology. Our approach enables the reconstruction of hysteresis nano-loops by determining the PR as a function of applied electric field. These hysteresis loops are then fitted to extract characteristic parameters that serve as measures of the ferroelectric properties of the sample. Various artifact decorrelation methods are employed to enhance measurement accuracy, and additional material properties can be assessed. Performing this procedure on a grid of points across the surface of the sample enables the creation of spatial maps. Furthermore, different techniques have been proposed to facilitate post-treatment analysis, incorporating algorithms for machine learning (K-means), phase separation, and mapping cross correlation, among others. Additionally, PySSPFM enables a more in-depth investigation of the material by studying the nanomechanical properties during poling, through the measurement of the resonance properties of the cantilever–tip–sample surface system. [ABSTRACT FROM AUTHOR]

Abstract Large carnivores play a pivotal regulating role in maintaining healthy and balanced ecosystems; however, most of them are rare and elusive, and knowledge about their resource consumption is scarce. Traditional methods based on morphological identification of undigested remains are labor intensive and often not sufficiently accurate, leading to errors and biased ecological inferences. Here, we developed a multi‐marker DNA metabarcoding approach to analyze the dietary diversity of giant otters (Pteronura brasiliensis) from fecal DNA while controlling predator species identity. We combined two mitochondrial markers, 12S rRNA and cytochrome c oxidase 1 (COI) gene, that target the full range of potential vertebrate and invertebrate prey. We compiled a local reference database of DNA barcodes for most potentially ingested fish, which were used to evaluate the specificity of the metabarcoding primers in silico. Most prey are identified at the species level (>90%) and the dietary profiles provided independently by the two markers are highly similar, whether in terms of list of prey or frequency of occurrences, hence validating the approach. We detected a higher number of rare fish prey with the 12S primers that amplified solely Teleost species while the degenerate COI primers revealed non‐fish prey (e.g., amphibians, snakes, birds, and earthworms) and confirmed predator species identity. This study demonstrated that scat DNA metabarcoding is particularly useful to provide in‐depth information on elusive carnivorous dietary profile. Our methodology opens up new opportunities to understand how top carnivores diet cope with the effects of anthropogenic alteration of ecosystems and identify conflicts with humans and livestock.

Abstract Changes in environmental conditions alter host–parasite interactions, raising the need for effective epidemiological surveillance. Developing operational, accurate, and cost‐effective methods to assess individual infection status and potential for pathogen spread is a prerequisite to anticipate future disease outbreaks in wild populations. For endoparasites, effective detection of infections usually relies on host‐lethal approaches, which are barely compatible with wildlife conservation objectives. Here, we used the brown trout (Salmo trutta)—Tetracapsuloides bryosalmonae host–parasite system to develop a non‐lethal method for endoparasite infection detection, hereafter called “uDNA” for urine DNA. The uDNA diagnostic test is based on the amplification of endoparasite DNA from host urine. We sampled wild fish (N = 111) from eight sites, let them excrete in individual buckets filled with mineral water and performed parasite DNA amplification from water filtration. We compared the results of the uDNA diagnostic test for host infection status and parasite load to those from kidney samples (the current standard method). uDNA was sensitive in determining host infection status (even for infected hosts showing no sign of the disease), since up to 90% of fish individuals were correctly assigned to their infection status. The quantity of uDNA detected from the hosts depended on the sampling sites, suggesting a spatial variation in the parasite spread. uDNA was positively, but weakly correlated with parasite load in the kidney. This correlation depended on the severity of macroscopic lesions caused by the disease and was negative in fish with severely damaged kidney, likely due to impaired urine excretion. The uDNA approach provides novel avenues to non‐lethally infer infection parameters from wildlife populations at large spatial scales. By targeting parasite transmission stage, uDNA is also valuable to get insights on the parasite fitness and the ecological and evolutionary dynamics of this host–parasite interaction.

Understanding how environmental gradients shape the spatial patterns of intraspecific genetic diversity is a central issue in ecological and evolutionary sciences. In riverine ecosystems, there is generally an increase in neutral genetic diversity downstream, as well as an increase in genetic differentiation among upstream populations. However, selective pressures may vary markedly along the upstream–downstream gradient, which could modify these patterns, but this has rarely been tested empirically. Here, we investigated how environmental gradients in a river network could shape the spatial patterns of intraspecific genetic diversity and differentiation in both neutral SNP markers and functional genetic markers putatively under natural selection (candidate SNPs associated with physiological functions and immune Major Histocompatibility Complex (MHC) loci) in wild brown trout populations. First, we showed that both the distance from the confluence and the centrality on the river network could explain the variation in genetic diversity and differentiation. Second, we found that both neutral and functional markers followed a similar pattern, with a higher genetic diversity and a lower genetic differentiation among populations that were more central and/or near to the confluence. This study highlights the importance of considering both the spatial and hydrological factors of a river network to understand and predict the role of dendritic connectivity in the spatial patterns of genetic diversity and differentiation in wild fish populations.

Abstract Epidemiological investigations implemented in wild and domestic ruminants evidenced a reservoir for Brucella in Capra ibex in the French Alps. Vaccination was considered as a possible way to control Brucella infection in this wildlife population. Twelve ibexes and twelve goats were allocated into four groups housed separately, each including six males or six non-pregnant females. Four to five animals were vaccinated and one or two animals were contact animals. Half of the animals were necropsied 45 days post-vaccination (pv), and the remaining ones at 90 days pv. Additional samples were collected 20 and 68 days pv to explore bacterial distribution in organs and humoral immunity. Neither clinical signs nor Brucella-specific lesions were observed and all vaccinated animals seroconverted. Brucella distribution and antibody profiles were highly contrasted between both species. Proportion of infected samples was significantly higher in ibex compared to goats and decreased between 45 and 90 days pv. Two male ibex presented urogenital excretion at 20 or 45 days pv. The bacterial load was higher 45 days in ibexes compared to goats, whereas it remained moderate to low 90 days pv in both species with large variability between animals. In this experiment, differences between species remained the main source of variation, with low impact of other individual factors. To conclude, multiplicative and shedding capacity of Rev.1 was much higher in ibex compared to goats within 90 days. These results provide initial information on the potential use in natura of a commercial vaccine.

Structural adhesive bonding has several advantages compared to other assembly techniques such as welding and riveting. Yet, creep is an important long-term phenomenon that needs to be considered for the design of such joints. To investigate this aspect, experimental investigations are needed at the scale of the adhesive layer. At such a scale, Arcan setting presents several advantages compared to other existing tests (analysis of different loads, limited edge effects) and was thus chosen for the development of an experimental approach aiming at providing creep characterization of adhesive layers. A mechanically operated testing machine was thus developed and is presented herein. To measure local strains of the adhesive layer, two linear variable differential transformer sensors are fixed on a support placed on the beaks of the Arcan sample according to two directions: normal and tangential to the bonded surface. The developed system (mechanical system and strain measurement) proved to be successful in investigating the creep behavior of adhesive layers while varying several parameters (load levels, type of load, temperature, adhesive thickness). [ABSTRACT FROM AUTHOR]

In tropical regions, most primary ecosystems have been replaced by mosaic landscapes in which species must cope with a large shift in the distribution of their habitat and associated food resources. Primates are particularly vulnerable to habitat modifications. Most species persist in small fragments surrounded by complex human-mediated matrices whose structure and connectivity may strongly influence their dispersal and feeding behavior. Behavioral plasticity appears to be a crucial parameter governing the ability of organisms to exploit the resources offered by new matrix habitats and thus to persist in fragmented habitats. In this study, we were interested in the dietary plasticity of the golden-crowned sifaka (Propithecus tattersalli), an endangered species of lemur, found only in the Daraina region in north-eastern Madagascar. We used a DNA-based approach combining the barcoding concept and Illumina next-generation sequencing to (i) describe the species diet across its entire range and (ii) evaluate the influence of landscape heterogeneity on diet diversity and composition. Faeces from 96 individuals were sampled across the entire species range and their contents were analyzed using the trnL metabarcoding approach. In parallel, we built a large DNA reference database based on a checklist of the plant species of the Daraina region. Our results suggest that golden-crowned sifakas exhibit remarkable dietary diversity with at least 130 plant species belonging to 80 genera and 49 different families. We highlighted an influence of both habitat type and openness on diet composition suggesting a high flexibility of foraging strategies. Moreover, we observed the presence of numerous cultivated and naturalized plants in the faeces of groups living in forest edge areas. Overall, our findings support our initial expectation that P. tattersalli is able to cope with the current level of alteration of the landscape and confirm our previous results on the distribution and the dispersal ability of this species.