Phaidra - University of Veterinary Medicine Vienna
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Polarization-insensitive optical coherence tomography using pseudo-depolarized reference light for mitigating birefringence-related image artifacts
No full textOptical coherence tomography (OCT) images are prone to image artifacts due to the birefringence of the sample or the optical system when a polarized light source is used for imaging. These artifacts can lead to degraded image quality and diagnostic information.We aim to mitigate these birefringence-related artifacts in OCT images by adding a depolarizer module in the reference arm of the interferometer.We investigated different configurations of liquid crystal patterned retarders as pseudo-depolarizers in the reference arm of OCT setups. We identified the most effective depolarization module layout for polarization artifact suppression for a spectral-domain OCT system based on a Michelson and a Mach-Zehnder interferometer.The performance of our approach was demonstrated in an achromatic quarter-wave plate allowing the selection of a variety of sample polarization states. A substantial improvement of the OCT signal magnitude was observed after placing the optimal depolarizer configuration, reducing the cross-polarization artifact from 5.7 to 1.8 dB and from 8.0 to 1.0 dB below the co-polarized signal for the fiber-based Michelson and Mach-Zehnder setup, respectively. An imaging experiment in the birefringent scleral tissue of a post-mortem alpine marmot eye and a mouse tail specimen further showcased a significant improvement in the detected signal intensity and an enhanced OCT image quality followed by a drastic elimination of the birefringence-related artifacts.Our study presents a simple yet cost-effective technique to mitigate birefringence-related artifacts in OCT imaging. This method can be readily implemented in existing OCT technology and improve the effectiveness of various OCT imaging applications in biomedicine
Dealing With the Complexity of Effective Population Size in Conservation Practice
No full textEffective population size (Ne) is one of the most important parameters in evolutionary biology, as it is linked to the long-term survival capability of species. Therefore, Ne greatly interests conservation geneticists, but it is also very relevant to policymakers, managers, and conservation practitioners. Molecular methods to estimate Ne rely on various assumptions, including no immigration, panmixia, random sampling, absence of spatial genetic structure, and/or mutation-drift equilibrium. Species are, however, often characterized by fragmented populations under changing environmental conditions and anthropogenic pressure. Therefore, the estimation methods\u27 assumptions are seldom addressed and rarely met, possibly leading to biased and inaccurate Ne estimates. To address the challenges associated with estimating Ne for conservation purposes, the COST Action 18134, Genomic Biodiversity Knowledge for Resilient Ecosystems (G-BiKE), organized an international workshop that met in August 2022 in Bra?ov, Romania. The overarching goal was to operationalize the current knowledge of Ne estimation methods for conservation practitioners and decision-makers. We set out to identify datasets to evaluate the sensitivity of Ne estimation methods to violations of underlying assumptions and to develop data analysis strategies that addressed pressing issues in biodiversity monitoring and conservation. Referring to a comprehensive body of scientific work on Ne, this meeting report is not intended to be exhaustive but rather to present approaches, workshop findings, and a collection of papers that serve as fruits of those efforts. We aimed to provide insights and opportunities to help bridge the gap between scientific research and conservation practice
Automated, longitudinal measures of drinking behavior provide insights into the social hierarchy in dairy cows
No full textDairy cows compete for feed and water access on commercial farms. In this study we used EloSteepness to assess the summed Elo winning probabilities (i.e., dominance) of 87 cows housed in a dynamic group and compared the resulting social hierarchies based on their steepness (i.e., the average degree of differences in winning probability between adjacently ranked individuals in the group, ranging from 0 to 1). We identified a hierarchy at the drinker with a steepness of 0.55 ± 0.02 (SD), whereas the hierarchy detected at the feeder during the same time period was 0.45 ± 0.02, indicating smaller dominance differences among cows when competing for feed compared with competing for water. Individual cows\u27 winning probabilities at the feeder and drinker were moderately correlated (rs = 0.55), and cows at the lower and upper ends of the hierarchy showed good agreement. We compared the drinker hierarchy between hot (i.e., temperature-humidity index [THI] ?72) and normal (i.e., THI <72) periods. The hierarchy steepness was similar in both hot (0.54 ± 0.03) and normal conditions (0.56 ± 0.03), and there was a strong correlation in cows\u27 individual winning probabilities across these periods (rs = 0.87). Cows with higher winning probability visited the drinker less frequently (hot: rs = -0.40, normal: rs = -0.33) but had a higher average daily water intake (hot: rs = 0.38, normal: rs = 0.37). We also found evidence that individual cows\u27 drinking times differ depending on their winning probability; cows with lower winning probability shifted their drinking times to before or after the visit peak after milking. Automatically identifying cows with consistently high or low winning probabilities using drinkers may help inform grouping decisions and water provision on farms
Molecular characterization, virulence and antimicrobial and biocidal susceptibility of selected bacteria isolated from the cloaca of nestling ospreys (Pandion haliaetus) from Mono Lake, California, USA
No full textIn the present study, the presence of the Enterobacterales, Staphylococcus spp., Mammaliicoccus spp., and Enterococcus spp. in cloacal samples of nestling ospreys (Pandion haliaetus), a fish-eating specialist, from Mono Lake, California, USA was examined by a multiphasic approach, including antimicrobial and biocide susceptibility testing, genotyping, and whole genome sequencing of selected isolates. The most commonly detected species was Escherichia coli, followed by Mammaliicoccus sciuri, Staphylococcus delphini, Enterococcus faecalis, Enterococcus faecium, Hafnia alvei, Klebsiella pneumoniae, Citrobacter braakii and single isolates of Edwardsiella tarda, Edwardsiella albertii, Klebsiella aerogenes, Plesiomonas shigelloides and Staphylococcus pseudintermedius. Multi-drug resistance (MDR) was observed in two E. coli isolates and in an Enterococcus faecium isolate. The MDR blaCTX-M-55-positive E. coli belonged to the pandemic clone ST58. The results of the present study suggest that nestling ospreys are exposed to MDR bacteria, possibly through the ingestion of contaminated fish. Ospreys may be good biosentinels for the presence of these microorganisms and antibiotic resistance in the local environment and the risk for other wildlife, livestock and humans
Mammals show faster recovery from capture and tagging in human-disturbed landscapes
No full textWildlife tagging provides critical insights into animal movement ecology, physiology, and behavior amid global ecosystem changes. However, the stress induced by capture, handling, and tagging can impact post-release locomotion and activity and, consequently, the interpretation of study results. Here, we analyze post-tagging effects on 1585 individuals of 42 terrestrial mammal species using collar-collected GPS and accelerometer data. Species-specific displacements and overall dynamic body acceleration, as a proxy for activity, were assessed over 20?days post-release to quantify disturbance intensity, recovery duration, and speed. Differences were evaluated, considering species-specific traits and the human footprint of the study region. Over 70% of the analyzed species exhibited significant behavioral changes following collaring events. Herbivores traveled farther with variable activity reactions, while omnivores and carnivores were initially less active and mobile. Recovery duration proved brief, with alterations diminishing within 4-7 tracking days for most species. Herbivores, particularly males, showed quicker displacement recovery (4 days) but slower activity recovery (7days). Individuals in high human footprint areas displayed faster recovery, indicating adaptation to human disturbance. Our findings emphasize the necessity of extending tracking periods beyond 1?week and particular caution in remote study areas or herbivore-focused research, specifically in smaller mammals
Comparative pathogenesis of Ethiopia/Habru/2014 Lineage-IV peste des petits ruminants virus in goats and cattle
No full textPeste des Petits Ruminants (PPR) is a highly contagious viral disease primarily affecting goats and sheep, with clinical manifestations ranging from peracute disease to subclinical infection, particularly in atypical hosts such as cattle. The role of atypical hosts such as cattle to the spread of PPR remains controversial, with conflicting reports in the literature. Despite its worldwide significance, considerable knowledge gaps exist regarding the pathogenesis and clinical progression in both primary and atypical hosts. This study aimed to elucidate the tissue tropism, pathogenesis, virus shedding, clinical progression, and pathology associated with experimental PPR virus infection in indigenous goats and cattle. To this end, 32 animals-16 goats and 16 cattle-were intranasally inoculated with the Ethiopia/Habru/2014 Lineage-IV strain of the PPR virus followed by detailed clinical evaluations and systematic sampling at pre-established intervals to assess serological conversion, viral shedding, and the pathogenesis of the infection across both species.The results show that goats exhibited typical clinical signs 4 days post-inoculation, with seroconversion by day 6 and early detection of viral RNA in swabs and tissues by day 3 and virus isolation starting day 4. In contrast, cattle exhibited minimal clinical signs, with seroconversion occurring at day 8 with viral RNA detected in tissue samples at day 4 and virus isolation starting day 6 in tissues and in a single nasal swab at day 8. Clinical scores and tissue positivity rates significantly differed between goats and cattle (P = 0.007 and P < 0.001, respectively). While goats exhibited expected gross and histopathological lesions, cattle showed only nonspecific lesions.Together, our findings highlight the importance of comparative pathology studies for better understanding virus dynamics and transmission pathways that may help inform more effective PPR control programs. Future research should explore the pathogenesis of different PPRV lineages in cattle, assessing variations in disease progression and potential for epidemiological impact
Interdisciplinary Animal Research Ethics-Challenges, Opportunities, and Perspectives
No full textCan nonhuman animals be used for the benefit of humans in a scientifically and morally justified manner and, if yes, how? Based on our own experiences as scholars from various academic backgrounds, we argue that this question can only be answered as an interdisciplinary and international endeavor, considering insights from research ethics and animal ethics as well as scientific and legal aspects. The aim of this article is to contribute to the foundation of the emerging field of animal research ethics. In doing so, we describe the following seven phases of animal research experiments: ethical, legal and social presumptions (phase 0), planning (phase I), review (phase II), conduct of experiments (phase III), publication/dissemination (phase IV), further exploitation of results (phase V), and evaluation (phase VI). In total, 20 key ethical, legal, and practical challenges that an ethical framework for the use of animals in research needs to address are identified and analyzed. Finally, we characterize the following four meta-challenges and opportunities associated with animal research ethics as a field: (1) moral pluralism, (2) the integration of views and positions outside the laboratory, (3) international plurality of conduct, standards, and legal norms, and (4) interdisciplinary education
Subcutaneous and orally self-administered high-dose carprofen shows favorable pharmacokinetic and tolerability profiles in male and female C57BL/6J mice
No full textSurgical interventions in mice require appropriate pain relief to ensure animal welfare and to avoid influence of pain on research findings. Carprofen is a non-steroidal anti-inflammatory drug commonly used as an analgesic for interventions inducing mild to moderate pain in laboratory rodents. Despite its frequent use, species-specific data on pharmacokinetics (PK), side effects, and potential impact on behavioral pain indicators are limited.We determined PK and tolerability profiles of carprofen in healthy male and female C57BL/6J mice (n = 42), administered at highest recommended doses via single subcutaneous (s.c.) injection (20 mg/kg) and oral self-administration (25 mg/kg/24 h) per drinking water (d.w.) for 5 days. Plasma concentrations were measured at various time points after the start of the treatment (n = 6 per time point), and side effects were evaluated using a modified Irwin test battery, hematology, and histopathology. Additionally, potential interference with cage-side behaviors commonly used for pain assessment, such as the mouse grimace scale, wheel running, burrowing, nesting, and grooming activity, was investigated.Maximum plasma concentrations of 133.4 ± 11.3 μg/ml were reached 1 h after single s.c. injection with an elimination half-life of 8.52 h. Intake from d.w. resulted in a steady state within 24 h after the start of the treatment with plasma levels of around 60 μg/ml over 5 days in both sexes. The medicated water was well-accepted, and increased d.w. intake was observed in the first 24 h after exposure (p< 0.0001). The Irwin test revealed only minor influence on tested behavior and physiological functions. However, during treatment via d.w., an increase in body temperature (p< 0.0001) was observed, as well as a reduction in voluntary wheel running activity by 49-70% in male mice. Moreover, grooming behavior was slightly affected. Hematology and histopathology were without pathological findings that could be attributed to carprofen treatment. High-dose carprofen can be considered safe and of favorable PK for both administration routes assessed in healthy C57BL/6J mice of both sexes. Further efficacy evaluation of carprofen as monoanalgesic or component of multimodal post-surgical regimens is clearly encouraged; however, the impact on behavioral markers used for pain assessment should be considered in this context
Correction: Workplace learning: the bidirectional relationship between stress and self-regulated learning in undergraduates
No full textNo abstract available
Workplace learning: the bidirectional relationship between stress and self-regulated learning in undergraduates
No full textThe present study focused on the relationships between various aspects of self-regulated learning (SRL) and stress among undergraduate health science students in workplace settings. Although both constructs are associated with academic achievement (Ahmady Set al., in J Educ Health Promotion 10:32, 2021, Cho KK et al., in BMC Med Educ 17:112, 2017), it is still unclear how they influence each other. Employing a longitudinal diary design, the aim of the present study was to examine whether perceived stress in the previous week impacts SRL-aspects in the current week and, conversely, whether SRL-aspects in the previous week impacts stress in the current week. Subjects were 192 undergraduate health sciences students in their workplace placements. SRL-aspects and stress were assessed using scales and previously tested single-item measures. The 21 SRL-aspects used in this study included cognition (learning strategies), motivation, emotion, perception of the learning environment, and regulation of these areas on a metalevel (monitoring and control). Data collected over 15 weeks were analyzed using multilevel vector autoregressive models, with the data nested within weeks and one model dedicated to each SRL-aspect and its relationship with stress. Among the 21 path estimates assessing the impact of prior stress on individual SRL-aspects, 10 were statistically significant. For individual SRL-aspects impacting stress, 7 out of 21 paths were statistically significant (p < .05). Notably, no model showed statistical significance of effects in both directions. Except for two results, cross-lagged relationships were negative, indicating that better SRL-aspects from the previous week resulted in reduced stress in the current week and vice versa. The effects for the cross-lagged paths from SRL-aspects to stress were predominantly of medium size, whereas the influence of stress on individual SRL-aspects was predominantly small. The present study highlights a potentially causal and mostly negative relationship between stress and various aspects of SRL, but also that the individual relationships require differentiated consideration. The results can be used to develop targeted interventions in the practical part of the training of health science students to reduce stress and improve specific aspects of SRL. Furthermore, these findings underscore assumptions regarding connections between anxiety and increased stress, negative relationships between stress and motivation, and the importance of effective time management strategies for stress reduction