A hypothetico-deductive approach to assessing the social function of chemical signalling in a non-territorial solitary carnivore

The function of chemical signalling in non-territorial solitary carnivores is still relatively unclear. Studies on territorial solitary and social carnivores have highlighted odour capability and utility, however the social function of chemical signalling in wild carnivore populations operating dominance hierarchy social systems has received little attention. We monitored scent marking and investigatory behaviour of wild brown bears Ursus arctos, to test multiple hypotheses relating to the social function of chemical signalling. Camera traps were stationed facing bear ‘marking trees’ to document behaviour by different age sex classes in different seasons. We found evidence to support the hypothesis that adult males utilise chemical signalling to communicate dominance to other males throughout the non-denning period. Adult females did not appear to utilise marking trees to advertise oestrous state during the breeding season. The function of marking by subadult bears is somewhat unclear, but may be related to the behaviour of adult males. Subadults investigated trees more often than they scent marked during the breeding season, which could be a result of an increased risk from adult males. Females with young showed an increase in marking and investigation of trees outside of the breeding season. We propose the hypothesis that females engage their dependent young with marking trees from a young age, at a relatively ‘safe’ time of year. Memory, experience, and learning at a young age, may all contribute towards odour capabilities in adult bears

The Search for Invariance: Repeated Positive Testing Serves the Goals of Causal Learning

Positive testing is characteristic of exploratory behavior, yet it seems to be at odds with the aim of information seeking. After all, repeated demonstrations of one’s current hypothesis often produce the same evidence and fail to distinguish it from potential alternatives. Research on the development of scientific reasoning and adult rule learning have both documented and attempted to explain this behavior. The current chapter reviews this prior work and introduces a novel theoretical account—the Search for Invariance (SI) hypothesis—which suggests that producing multiple positive examples serves the goals of causal learning. This hypothesis draws on the interventionist framework of causal reasoning, which suggests that causal learners are concerned with the invariance of candidate hypotheses. In a probabilistic and interdependent causal world, our primary goal is to determine whether, and in what contexts, our causal hypotheses provide accurate foundations for inference and intervention—not to disconfirm their alternatives. By recognizing the central role of invariance in causal learning, the phenomenon of positive testing may be reinterpreted as a rational information-seeking strategy

Supraspinal fatigue in human inspiratory muscles with repeated sustained maximal efforts

To investigate the involvement of supraspinal fatigue in the loss of maximal inspiratory pressure (PImax), we fatigued the inspiratory muscles. Six participants performed 5 sustained maximal isometric inspiratory efforts (15-s contractions, duty cycle ~75%) which reduced PImax, as measured from esophageal and mouth pressure, to around half of their initial maximums. Transcranial magnetic stimulation (TMS) delivered over the motor cortex near the beginning and end of each maximal effort evoked superimposed twitch-like increments in the ongoing PImax, increasing from ~1.0% of PImax in the unfatigued contractions to ≥40% of ongoing PImax for esophageal and mouth pressures. The rate of increase in the superimposed twitch as PImax decreased with fatigue was not significantly different between the esophageal and mouth pressure measures. The inverse relationship between superimposed twitch pressure and PImax indicates a progressive decline in the ability of motor cortical output to drive the inspiratory muscles maximally, leading to the development of supraspinal fatigue. TMS also evoked silent periods in the electromyographic recordings of diaphragm, scalenes, and parasternal intercostal. The duration of the silent period increased with fatigue in all three muscles, which suggests greater intracortical inhibition, with the largest change observed in the diaphragm. The peak rate of relaxation in pressure during the silent period slowed as fatigue developed, indicating peripheral contractile changes in the active inspiratory muscles. These changes in the markers of fatigue show that both central and peripheral fatigue contribute to the loss in PImax when inspiratory muscles are fatigued with repeated sustained maximal efforts. NEW & NOTEWORTHY When the inspiratory muscles are fatigued with repeated sustained maximal efforts, supraspinal fatigue, a component of central fatigue, contributes to the loss in maximal inspiratory pressure. The presence of supraspinal fatigue was confirmed by the increase in amplitude of twitch-like increments in pressure evoked by motor cortical stimulation during maximal efforts, indicating that motor cortical output was not maximal as extra muscle force could be generated to increase inspiratory pressure

Extreme behavioural shifts by baboons exploiting risky, resource-rich, human-modified environments

Abstract A range of species exploit anthropogenic food resources in behaviour known as ‘raiding’. Such behavioural flexibility is considered a central component of a species’ ability to cope with human-induced environmental changes. Here, we study the behavioural processes by which raiding male chacma baboons (Papio ursinus) exploit the opportunities and mitigate the risks presented by raiding in the suburbs of Cape Town, South Africa. Ecological sampling and interviews conducted with ‘rangers’ (employed to manage the baboons’ space use) revealed that baboons are at risk of being herded out of urban spaces that contain high-energy anthropogenic food sources. Baboon-attached motion/GPS tracking collars showed that raiding male baboons spent almost all of their time at the urban edge, engaging in short, high-activity forays into the urban space. Moreover, activity levels were increased where the likelihood of deterrence by rangers was greater. Overall, these raiding baboons display a time-activity balance that is drastically altered in comparison to individuals living in more remote regions. We suggest our methods can be used to obtain precise estimates of management impact for this and other species in conflict with people

Preclinical Insights Into the Effects of Frequency and Pulse Width on Evoked Compound Action Potential Morphology During Spinal Cord Stimulation

\ua9 2025 The Authors. Objectives: High-frequency spinal cord stimulation (SCS) at 1000 Hz was shown to reduce evoked compound action potential (ECAP) amplitude, likely owing to asynchronous firing of dorsal column (DC) axons. To investigate the relationship between SCS parameters and DC axon activation, we analyzed ECAP morphology across different stimulation frequencies and pulse widths (PWs). Materials and Methods: Adult male Sprague-Dawley rats (200–400 g) were implanted with an epidural lead. To study SCS frequency effects, baseline recordings were taken at 2 Hz, followed by tests at 50, 200, 500, and 1000 Hz, with 2 Hz recovery periods; 200 Hz also was applied in a pig with an epidurally implanted lead. PW effects were assessed in rats by increasing the PW from 50 to 1000 μs, in 50 μs increments per minute. Results: In contrast to 50 Hz, SCS at 200, 500, and 1000 Hz reduced ECAP amplitude and increased peak latencies and ECAP width. Conduction velocity (CV) was reduced at 500 and 1000 Hz. Recovery intervals at 2 Hz, after 200, 500, and 1000 Hz, showed a gradual return to baseline values for ECAP morphology parameters. Similar effects occurred in the pig. Increasing PW prolonged peak latencies, with ECAP amplitudes decreasing from 200 to 250 μs. Conclusions: DC axon responses to SCS at increasing frequencies or PWs depend on their recovery state, as reflected in changes to ECAP morphology and CV. These effects may result from desynchronization, demyelination, or differences within fiber recruitment. Further investigation into these mechanisms can improve the efficacy of SCS therapy

Proteases of haematophagous arthropod vectors are involved in blood-feeding, yolk formation and immunity : a review

Ticks, triatomines, mosquitoes and sand flies comprise a large number of haematophagous arthropods considered vectors of human infectious diseases. While consuming blood to obtain the nutrients necessary to carry on life functions, these insects can transmit pathogenic microorganisms to the vertebrate host. Among the molecules related to the blood-feeding habit, proteases play an essential role. In this review, we provide a panorama of proteases from arthropod vectors involved in haematophagy, in digestion, in egg development and in immunity. As these molecules act in central biological processes, proteases from haematophagous vectors of infectious diseases may influence vector competence to transmit pathogens to their prey, and thus could be valuable targets for vectorial control

Teaching clinical informatics to third-year medical students: negative results from two controlled trials

BACKGROUND: Prior educational interventions to increase seeking evidence by medical students have been unsuccessful. METHODS: We report two quasirandomized controlled trials to increase seeking of medical evidence by third-year medical students. In the first trial (1997–1998), we placed computers in clinical locations and taught their use in a 6-hour course. Based on negative results, we created SUMSearch(TM), an Internet site that automates searching for medical evidence by simultaneous meta-searching of MEDLINE and other sites. In the second trial (1999–2000), we taught SUMSearch's use in a 5½-hour course. Both courses were taught during the medicine clerkship. For each trial, we surveyed the entire third-year class at 6 months, after half of the students had taken the course (intervention group). The students who had not received the intervention were the control group. We measured self-report of search frequency and satisfaction with search quality and speed. RESULTS: The proportion of all students who reported searching at least weekly for medical evidence significantly increased from 19% (1997–1998) to 42% (1999–2000). The proportion of all students who were satisfied with their search results increased significantly between study years. However, in neither study year did the interventions increase searching or satisfaction with results. Satisfaction with the speed of searching was 27% in 1999–2000. This did not increase between studies years and was not changed by the interventions. CONCLUSION: None of our interventions affected searching habits. Even with automated searching, students report low satisfaction with search speed. We are concerned that students using current strategies for seeking medical evidence will be less likely to seek and appraise original studies when they enter medical practice and have less time

Cultural adaptation and psychometric evaluation of the Swedish version of the Reproductive Concerns After Cancer (RCAC) scale

BACKGROUND: Reproductive concerns are common among young cancer survivors and include worries related to different aspects of fertility and parenthood. The Reproductive Concerns After Cancer (RCAC) scale is an 18-item scale with six dimensions, developed to capture a variety of such concerns. The aim of the present study was to describe the cultural adaptation of the RCAC scale into Swedish and evaluate its psychometric properties among young women who have undergone treatment for cancer. METHODS: The RCAC was forward translated from English into Swedish and assessed for cultural adaptation based on a two-panel approach followed by cognitive interviews with the target group. For the psychometric evaluation, a Swedish cohort of 181 female young adult breast cancer survivors completed a survey including the RCAC scale approximately 1.5 years post-diagnosis. Psychometric properties were examined by analyses of construct validity (confirmatory factor analysis and convergent validity), data quality (score distribution, floor and ceiling effects), reliability and known-groups validity. RESULTS: The confirmatory factor analysis yielded an acceptable fit (RMSEA 0.08, SRMR 0.09, CFI 0.92). Convergent validity was demonstrated by a negative correlation of moderate size (- 0.36) between the RCAC total score and the emotional function scale of the EORTC QLQ-C30. Reliability measured with Revelle Ω total was satisfactory (0.73-0.92) for five of the dimensions, and poor for the dimension Becoming pregnant (Revelle Ω total = 0.60); Cronbach's alpha showed a similar pattern. Known-groups validity was indicated by significant RCAC mean score differences (MD), reflecting more concerns among women with a certain (MD 4.56 [95% CI 3.13 to 5.99]) or uncertain (MD 3.41 [95% CI 1.68 to 5.14]) child wish compared to those with no wish for (additional) children. CONCLUSION: The translation and cultural adaptation of the Swedish RCAC has resulted in a scale demonstrating construct and known-groups validity, and satisfactory reliability for five of six dimensions. The dimension Becoming pregnant showed non-optimal internal consistency and should undergo further evaluation. The Swedish RCAC is recommended to be used in research settings for measurement of concerns related to fertility and parenthood in young women with cancer

Police performance measurement: an annotated bibliography

This study provides information to assist those involved in performance measurement in police organisations. The strategies used to identify the literature are described. Thematic sections cover; general overviews; methodological issues; performance management in other industries; national, international and cross-national studies; frameworks (e.g. Compstat; the Balanced Scorecard); criticisms (particularly unintended consequences); crime-specific measures; practitioner guides; performance evaluation of individual staff; police department plans and evaluations; annotated bibliographies in related areas, and; other literature. Our discussion offers two conclusions: the measures best aligned with performance are typically more expensive, while most operational data should only provide contextual information; the philosophy of open governance should be pursued to promote transparency, accountability and communication to improve police performance