914 research outputs found

    Subchondral bone density distribution of the talus in clinically normal Labrador Retrievers

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    Background: Bones continually adapt their morphology to their load bearing function. At the level of the subchondral bone, the density distribution is highly correlated with the loading distribution of the joint. Therefore, subchondral bone density distribution can be used to study joint biomechanics non-invasively. In addition physiological and pathological joint loading is an important aspect of orthopaedic disease, and research focusing on joint biomechanics will benefit veterinary orthopaedics. This study was conducted to evaluate density distribution in the subchondral bone of the canine talus, as a parameter reflecting the long-term joint loading in the tarsocrural joint. Results: Two main density maxima were found, one proximally on the medial trochlear ridge and one distally on the lateral trochlear ridge. All joints showed very similar density distribution patterns and no significant differences were found in the localisation of the density maxima between left and right limbs and between dogs. Conclusions: Based on the density distribution the lateral trochlear ridge is most likely subjected to highest loads within the tarsocrural joint. The joint loading distribution is very similar between dogs of the same breed. In addition, the joint loading distribution supports previous suggestions of the important role of biomechanics in the development of OC lesions in the tarsus. Important benefits of computed tomographic osteoabsorptiometry (CTOAM), i.e. the possibility of in vivo imaging and temporal evaluation, make this technique a valuable addition to the field of veterinary orthopaedic research

    Optimising the effect of noise reduction algorithm ClearVoice in cochlear implant users by increasing the maximum comfort levels

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    Objective: ClearVoice is a single-microphone noise reduction algorithm in Advanced Bionics cochlear implant(CI) systems with the aim to improve performance in background noise. The present study investigated a hypothesised increased effect of ClearVoice if combined with a structural increase of maximum comfort stimulation levels (M-levels) in the CI fitting. Design: We tested performance with ClearVoice (Medium) in four conditions, defined by combined settings of ClearVoice off/on and with/without 5% increase of M-levels. The main outcome measures were the Acceptable Noise Level (ANL) and the speech reception threshold in continuous background noise (SRTn). Study sample: Participants were 16 experienced cochlear implant recipients with Advanced Bionics implants and a Naida Q70 processor. Results: The ANL significantly improved by using either ClearVoice or an increase of M-levels. Combining both settings gave the largest improvement in ANL. For the SRTn, we found a small, but significant interaction between ClearVoice and an increase of M-levels, implying that ClearVoice improved speech understanding slightly, but only if combined with a 5% increase of M-levels. Conclusions: Optimal profit from ClearVoice is obtained if combined with a structural 5% increase of M-levels

    A Coding Scheme for Other-initiated Repair Across Languages

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    We provide an annotated coding scheme for other-initiated repair, along with guidelines for building collections and aggregating cases based on interactionally relevant similarities and differences. The questions and categories of the scheme are grounded in inductive observations of conversational data and connected to a rich body of work on other-initiated repair in conversation analysis. The scheme is developed and tested in a 12-language comparative project and can serve as a stepping stone for future work on other-initiated repair and the systematic comparative study of conversational structures

    Great tits responding to territorial intrusions sing less but alarm more on colder days

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    Bird song transmits information required to defend territories and attract mates. These functions contribute to fitness by affecting survival and reproductive success. Singing is also costly due to physiological costs. We used observational data to evaluate support for the hypothesis that lower temperatures result in decreased singing behaviour in wild great tits due to increased energy consumption during cold conditions required for thermoregulation. More than 6,500 simulated territorial intrusions were performed over an 8‐year period in twelve nest box populations of great tits Parus major south of Munich, Germany. We measured song rate as well as the number of alarm calls and the aggressive response of territorial males to a simulated territorial intrusion. We found a decrease in song rate with decreasing current temperature, but also a concurrent increase in the number of alarm calls. Night temperature did not affect these acoustic traits. We conclude that warmer conditions allow birds to choose more energetically expensive (yet functionally superior) activities during territorial intrusions, thereby facilitating avoidance of physical aggressiveness during territorial intrusions

    Protein deprivation facilitates the independent evolution of behavior and morphology

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    Ecological conditions such as nutrition can change genetic covariances between traits and accelerate or slow down trait evolution. As adaptive trait correlations can become maladaptive following rapid environmental change, poor or stressful environments are expected to weaken genetic covariances, thereby increasing the opportunity for independent evolution of traits. Here, we demonstrate the differences in genetic covariance among multiple behavioral and morphological traits (exploration, aggression, and body weight) between southern field crickets (Gryllus bimaculatus) raised in favorable (free-choice) versus stressful (protein-deprived) nutritional environments. We also quantify the extent to which differences in genetic covariance structures contribute to the potential for the independent evolution of these traits. We demonstrate that protein-deprived environments tend to increase the potential for traits to evolve independently, which is caused by genetic covariances that are significantly weaker for crickets raised on protein-deprived versus free-choice diets. The weakening effects of stressful environments on genetic covariances tended to be stronger in males than in females. The weakening of the genetic covariance between traits under stressful nutritional environments was expected to facilitate the opportunity for adaptive evolution across generations. Therefore, the multivariate gene-by-environment interactions revealed here may facilitate behavioral and morphological adaptations to rapid environmental change

    Effects of multiple-dose ponesimod, a selective SIP1 receptor modulator, on lymphocyte subsets in healthy humans

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    This study investigated the effects of ponesimod, a selective SIP1 receptor modulator, on T lymphocyte subsets in 16 healthy subjects. Lymphocyte subset proportions and absolute numbers were determined at baseline and on Day 10, after once-daily administration of ponesimod (10 mg, 20 mg, and 40 mg each consecutively for 3 days) or placebo (ratio 3: 1). The overall change from baseline in lymphocyte count was -1,292 +/- 340x10(6) cells/L and 275 +/- 486x10(6) cells/L in ponesimod- and placebo-treated subjects, respectively. This included a decrease in both T and B lymphocytes following ponesimod treatment. A decrease in naive CD4(+) T cells (CD45RA(+)CCR7(+)) from baseline was observed only after ponesimod treatment (-113 +/- 98x10(6) cells/L, placebo: 0 +/- 18x10(6) cells/L). The number of T-cytotoxic (CD3(+)CD8(+)) and T-helper (CD3(+)CD4(+)) cells was significantly altered following ponesimod treatment compared with placebo. Furthermore, ponesimod treatment resulted in marked decreases in CD4(+) T-central memory (CD45RA(-)CCR7(+)) cells (-437 +/- 164x10(6) cells/L) and CD4(+) T-effector memory (CD45RA(-)CCR7(-)) cells (-131 +/- 57x10(6) cells/L). In addition, ponesimod treatment led to a decrease of -228 +/- 90x10(6) cells/L of gut-homing T cells (CLA(-)integrin beta 7(+)). In contrast, when compared with placebo, CD8(+) T-effector memory and natural killer (NK) cells were not significantly reduced following multiple-dose administration of ponesimod. In summary, ponesimod treatment led to a marked reduction in overall T and B cells. Further investigations revealed that the number of CD4(+) cells was dramatically reduced, whereas CD8(+) and NK cells were less affected, allowing the body to preserve critical viral-clearing functions

    Indirect genetic effects: a key component of the genetic architecture of behaviour

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    Behavioural ecology research increasingly focuses on why genetic behavioural variation can persist despite selection. Evolutionary theory predicts that directional selection leads to evolutionary change while depleting standing genetic variation. Nevertheless, evolutionary stasis may occur for traits involved in social interactions. This requires tight negative genetic correlations between direct genetic effects (DGEs) of an individual's genes on its own phenotype and the indirect genetic effects (IGEs) it has on conspecifics, as this could diminish the amount of genetic variation available to selection to act upon. We tested this prediction using a pedigreed laboratory population of Mediterranean field crickets (Gryllus bimaculatus), in which both exploratory tendency and aggression are heritable. We found that genotypes predisposed to be aggressive (due to DGEs) strongly decreased aggressiveness in opponents (due to IGEs). As a consequence, the variance in total breeding values was reduced to almost zero, implying that IGEs indeed greatly contribute to the occurrence of evolutionary stasis. IGEs were further associated with genetic variation in a non-social behaviour: explorative genotypes elicited most aggression in opponents. These key findings imply that IGEs indeed represent an important overlooked mechanism that can impact evolutionary dynamics of traits under selection
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