1,075 research outputs found

    Abnormal Coloration in Bighorn Sheep (Ovis canadensis)

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    Despite no mention of abnormal coloration in bighorn sheep (Ovis canadensis) in two earlier reviews addressing that subject, leucism, piebaldism, and melanism do occur in that species. Presented herein is a compilation of observations of abnormally colored bighorn sheep (Ovis canadensis) assembled with information obtained from personal observations and the use of on-line literature search services, other on-line searches, private interviews, and a questionnaire. The majority of abnormally colored bighorn sheep have been described as white or albinistic . Review of images provided by respondents, however, verified that the majority of such reports were of leucistic individuals. White or leucistic bighorn sheep have been described from 23 specific geographic areas distributed among one Canadian province, one state in Mexico, and seven of the western United States; reports of piebaldism or of melanism are much less frequent

    Feral Horses, Feral Asses, and Professional Politicians: Broodings From a Beleaguered Biologist

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    As a member of National Wild Horse and Burro Advisory Board, I gained insight into several aspects of feral equid management that previously had been somewhat cryptic. Foremost in my experience, though, was the dedication and professionalism of the board members with whom I served. During my tenure, the professional approach to management and the frustration faced by employees within the Horse and Burro Program became increasingly apparent. Further came the realization that the effectiveness of the board and program can be improved substantially, if (1) the board is provided the opportunity to rebut or counter incorrect or misleading information received during public testimony, and those statements are shared with elected officials; (2) any member of the Board whose term expires can remain involved in board activities until that board member is reappointed or replaced; and (3) congressional representatives place the well-being of public rangelands ahead of personal ambitions and political expediency. In the absence of corrective actions, the public rangelands will continue to deteriorate, and the concomitant impacts to native species and feral equids will remain unabated, if not exacerbated

    Time-delayed feedback control in astrodynamics

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    In this paper we present time-delayed feedback control (TDFC) for the purpose of autonomously driving trajectories of nonlinear systems into periodic orbits. As the generation of periodic orbits is a major component of many problems in astodynamics we propose this method as a useful tool in such applications. To motivate the use of this method we apply it to a number of well known problems in the astrodynamics literature. Firstly, TDFC is applied to control in the chaotic attitude motion of an asymmetric satellite in an elliptical orbit. Secondly, we apply TDFC to the problem of maintaining a spacecraft in a periodic orbit about a body with large ellipticity (such as an asteroid) and finally, we apply TDFC to eliminate the drift between two satellites in low Earth orbits to ensure their relative motion is bounded

    On the Mechanism of Time--Delayed Feedback Control

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    The Pyragas method for controlling chaos is investigated in detail from the experimental as well as theoretical point of view. We show by an analytical stability analysis that the revolution around an unstable periodic orbit governs the success of the control scheme. Our predictions concerning the transient behaviour of the control signal are confirmed by numerical simulations and an electronic circuit experiment.Comment: 4 pages, REVTeX, 4 eps-figures included Phys. Rev. Lett., in press also available at http://athene.fkp.physik.th-darmstadt.de/public/wolfram.htm

    CD14 and ALPK1 Affect Expression of Tight Junction Components and Proinflammatory Mediators upon Bacterial Stimulation in a Colonic 3D Organoid Model

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    Cd14 and Alpk1 both encode pathogen recognition receptors and are known candidate genes for affecting severity in inflammatory bowel diseases. CD14 acts as a coreceptor for bacterial lipopolysaccharide (LPS), while ALPK1 senses ADP-D-glycero-beta-D-manno-heptose, a metabolic intermediate of LPS biosynthesis. Intestinal barrier integrity can be influenced by CD14, whereas to date, the role of ALPK1 in maintaining barrier function remains unknown. We used colon-derived 3D organoids, first characterised for growth, proliferation, stem cell markers, and expression of tight junction (TJ) components using qPCR and immunohistochemistry. They showed characteristic crypt stem cells, apical shedding of dead cells, and TJ formation. Afterwards, organoids of different genotypes (WT, Il10-/-, Cd14-/-, and Alpk1-/-) were then stimulated with either LPS or Escherichia coli Nissle 1917 (EcN). Gene expression and protein levels of cytokines and TJ components were analysed. WT organoids increased expression of Tnfα and tight junction components. Cd14-/- organoids expressed significantly less Tnfα and Ocln after LPS stimulation than WT organoids but reacted similarly to WT organoids after EcN stimulation. In contrast, compared to WT, Alpk1-/- organoids showed decreased expression of different TJ and cytokine genes in response to EcN but not LPS. However, Western blotting revealed an effect of ALPK1 on TJ protein levels. These findings demonstrate that Cd14, but not Alpk1, alters the response to LPS stimulation in colonic epithelial cells, whereas Alpk1 is involved in the response upon bacterial challenge. © 2020 Pascal Brooks et al

    Measuring endogenous corticosterone in laboratory mice - a mapping review, meta-analysis, and open source database

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    Evaluating stress in laboratory animals is a key principle in animal welfare. Measuring corticosterone is a common method to assess stress in laboratory mice. There are, however, numerous methods to measure glucocorticoids with differences in sample matrix (e.g., plasma, urine) and quantification techniques (e.g., enzyme immunoassay or radioimmunoassay). Here, the authors present a mapping review and a searchable database, giving a complete overview of all studies mea­suring endogenous corticosterone in mice up to February 2018. For each study, information was recorded regarding mouse strain and sex; corticosterone sample matrix and quantification technique; and whether the study covered the research theme animal welfare, neuroscience, stress, inflammation, or pain (the themes of specific interest in our con­sortium). Using all database entries for the year 2012, an exploratory meta-regression was performed to determine the effect of predictors on basal corticosterone concentrations. Seventy-five studies were included using the predictors sex, time-since-lights-on, sample matrix, quantification technique, age of the mice, and type of control. Sex, time-since-lights-on, and type of control significantly affected basal corticosterone concentrations. The resulting database can be used, inter alia, for preventing unnecessary duplication of experiments, identifying knowledge gaps, and standardizing or heterogenizing methodologies. These results will help plan more efficient and valid experiments in the future and can answer new questions in silico using meta-analyses

    P11 promoter methylation predicts the antidepressant effect of electroconvulsive therapy

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    Although electroconvulsive therapy (ECT) is among the most effective treatment options for pharmacoresistant major depressive disorder (MDD), some patients still remain refractory to standard ECT practise. Thus, there is a need for markers reliably predicting ECT non/response. In our study, we have taken a novel translational approach for discovering potential biomarkers for the prediction of ECT response. Our hypothesis was that the promoter methylation of p11, a multifunctional protein involved in both depressive-like states and antidepressant treatment responses, is differently regulated in ECT responders vs. nonresponders and thus be a putative biomarker of ECT response. The chronic mild stress model of MDD was adapted with the aim to obtain rats that are resistant to conventional antidepressant drugs (citalopram). Subsequently, electroconvulsive stimulation (ECS) was used to select responders and nonresponders, and compare p11 expression and promoter methylation. In the rat experiments we found that the gene promoter methylation and expression of p11 significantly correlate with the antidepressant effect of ECS. Next, we investigated the predictive properties of p11 promoter methylation in two clinical cohorts of patients with pharmacoresistant MDD. In a proof-of-concept clinical trial in 11 patients with refractory MDD, higher p11 promoter methylation was found in responders to ECT. This finding was replicated in an independent sample of 65 patients with pharmacoresistant MDD. This translational study successfully validated the first biomarker reliably predicting the responsiveness to ECT. Prescreening of this biomarker could help to identify patients eligible for first-line ECT treatment and also help to develop novel antidepressant treatment procedures for depressed patients resistant to all currently approved antidepressant treatments.Peer reviewe

    A systematic mapping review of the evolution of the rat Forced Swim Test: Protocols and outcome parameters

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    As depression is projected to become the leading mental disease burden globally by 2030, understanding the underlying pathology, as well as screening potential anti-depressants with a higher efficacy, faster onset of action, and/or fewer side-effects is essential. A commonly used test for screening novel antidepressants and studying depression-linked aspects in rodents is the Porsolt Forced Swim Test. The present systematic mappping review gives a comprehensive overview of the evolution and of the most prevalently used set-ups of this test in rats, including the choice of animals (strain, sex, and age), technical aspects of protocol and environment, as well as reported outcome measures. Additionally, we provide an accessible list of all existing publications, to support informed decision-making for procedural and technical aspects of the test, to thereby enhance reproducibility and comparability. This should further contribute to reducing the number of unnecessarily replicated experiments, and consequently, reduce the number of animals used in future
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