227 research outputs found

    A bioassay method for the pheromone(s) of the bont tick Amblyomma hebraeum Koch

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    A bioassay was developed which enabled the detection of the pheromones of the boot tick (Amblyomma hebraeum Koch) within 2 hours with a reproducibility of 82 ± 13%. Dried, solvent extracted ticks were glued onto the shaved backs of rabbits. Those ticks to which pheromone extract was subsequently applied strongly attracted females of the same species. In a 2-way choice test a cork disc impregnated with pheromone extract was even more attractive to female ticks than a treated dried tick.This article has been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-Format

    Neurosecretion in Ornithodoros savignyi (Audouin) (Ixodoidea : Argasidae). The distribution of neurosecretory cells in the brain

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    The arrangement of the brain and peripheral nerves in Ornithodoros savignyi (Audouin) is similar to that of other argasid and ixodid ticks. Histological studies, using a specialized staining technique (aldehyde fuchsin), have shown 15 groups of neurosecretory cells in the cortex of the brain.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    The activity of insect juvenile hormone mimics in larval Amblyomma hebraeum Koch (Acarina : Metastriata : Ixodidae)

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    A total of 14 insect juvenile hormone mimics was tested for activity in Amblyomma hebraeum by exposing newly engorged larvae to filter paper impregnated with hormone mimics. The most active compounds used in this assay were HS 103 (6-ethyl-3-pyridyl geranyl ether; EC₅₀ =0,0018 mg/ cm²), ZR 512 (Ethyl 3, 7, 11-trimethyldodeca-2,4-dienoate; EC₅₀= 0,0022 mg/cm²), HS 2 (6- methyl-3- pyridyl geranyl ether; EC₅₀=0,0035 mg/cm2), ZR 615 (N-ethyl 3, 7, 11-trimethyldodeca- 2, 4- dieneamide; EC₅₀=0, 0035 mg/cm²), ZR 777 (Prop-2-ynyl 3, 7, 11-trimethyldodeca-2, 4-dienoate; EC₅₀=0, 0039 mg/ cm²) and ZR 515 (Isopropyl-11-methoxy 3, 7, 11-trimethyldodeca-2, 4-dienoate; EC₅₀ = 0,0094 mg/cm²). Activity in this assay was similar to that reported in insects and was consistent with the susceptibility of these compounds to metabolic inactivation. The results suggest that ZR 615 may be of possible use in tick control.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    The use of frequency diagrams in the survey of resistance to pesticides in ticks in southern Africa

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    A method whereby resistance data can be analysed by means of frequency distributions is described. This method established that Rhipicephalus appendiculatus and R. evertsi evertsi show either little or only developing resistance to the pesticides chlorfenvinphos and dioxathion. Boophilus spp., however, show more instances and higher levels of resistance to these 2 pesticides.This article has been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-Format

    Impact of 5α-reductase inhibitor and α-blocker therapy for benign prostatic hyperplasia on prostate cancer incidence and mortality

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    Objective: To investigate the use of 5α-reductase inhibitors (5ARIs) and α-blockers among men with benign prostatic hyperplasia (BPH) in relation to prostate cancer (PCa) incidence, severity and mortality. Patients and Methods: A retrospective 20-year cohort study in men residing in Saskatchewan, aged 40–89 years, with a BPH-coded medical claim between 1995 and 2014, was conducted. Cox proportional hazards regression was used to compare incidence of PCa diagnosis, metastatic PCa, Gleason score 8–10 PCa, and PCa mortality among 5ARI users (n = 4 571), α-blocker users (n = 7 764) and non-users (n = 11 677). Results: In comparison with both non-users and α-blocker users, 5ARI users had a ~40% lower risk of a PCa diagnosis (11.0% and 11.4% vs 5.8%, respectively), and α-blocker users had an 11% lower risk of a PCa diagnosis compared with non-users. Overall, the incidence of metastatic PCa and PCa mortality was not significantly different among 5ARI or α-blocker users compared with non-users (adjusted hazard ratios [HR] of metastatic PCa: 1.12 and 1.13, respectively, and PCa mortality: 1.11 and 1.18, respectively, P > 0.05 for both drugs), but both 5ARI and a-blocker users had ~30% higher risk of Gleason score 8–10 cancer, adjusted HR 1.37, 95% confidence interval [CI] 1.03–1.82, P = 0.03, and adjusted HR 1.28, 95% CI 1.03–1.59, P = 0.02, respectively compared with non-users. Conclusion: The use of 5ARIs was associated with lower risk of PCa diagnosis, regardless of comparison group. Risk of high grade PCa was higher among both 5ARI users and α-blocker users compared with non-users; however, this did not translate into higher risk of PCa mortality

    Emotion, Meaning, and Appraisal Theory

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    According to psychological emotion theories referred to as appraisal theory, emotions are caused by appraisals (evaluative judgments). Borrowing a term from Jan Smedslund, it is the contention of this article that psychological appraisal theory is “pseudoempirical” (i.e., misleadingly or incorrectly empirical). In the article I outline what makes some scientific psychology “pseudoempirical,” distinguish my view on this from Jan Smedslund’s, and then go on to show why paying heed to the ordinary meanings of emotion terms is relevant to psychology, and how appraisal theory is methodologically off the mark by employing experiments, questionnaires, and the like, to investigate what follows from the ordinary meanings of words. The overarching argument of the article is that the scientific research program of appraisal theory is fundamentally misguided and that a more philosophical approach is needed to address the kinds of questions it seeks to answer

    Equilibrium and dynamical properties of two dimensional self-gravitating systems

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    A system of N classical particles in a 2D periodic cell interacting via long-range attractive potential is studied. For low energy density UU a collapsed phase is identified, while in the high energy limit the particles are homogeneously distributed. A phase transition from the collapsed to the homogeneous state occurs at critical energy U_c. A theoretical analysis within the canonical ensemble identifies such a transition as first order. But microcanonical simulations reveal a negative specific heat regime near UcU_c. The dynamical behaviour of the system is affected by this transition : below U_c anomalous diffusion is observed, while for U > U_c the motion of the particles is almost ballistic. In the collapsed phase, finite NN-effects act like a noise source of variance O(1/N), that restores normal diffusion on a time scale diverging with N. As a consequence, the asymptotic diffusion coefficient will also diverge algebraically with N and superdiffusion will be observable at any time in the limit N \to \infty. A Lyapunov analysis reveals that for U > U_c the maximal exponent \lambda decreases proportionally to N^{-1/3} and vanishes in the mean-field limit. For sufficiently small energy, in spite of a clear non ergodicity of the system, a common scaling law \lambda \propto U^{1/2} is observed for any initial conditions.Comment: 17 pages, Revtex - 15 PS Figs - Subimitted to Physical Review E - Two column version with included figures : less paper waste

    Dairy foods, calcium, and risk of breast cancer overall and for subtypes defined by estrogen receptor status: a pooled analysis of 21 cohort studies

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    Background: Epidemiologic studies examining the relations between dairy product and calcium intakes and breast cancer have been inconclusive, especially for tumor subtypes. Objective: To evaluate the associations between intakes of specific dairy products and calcium and risk of breast cancer overall and for subtypes defined by estrogen receptor (ER) status. Method: We pooled the individual-level data of over 1 million women who were followed for a maximum of 8-20 years across studies. Associations were evaluated for dairy product and calcium intakes and risk of incident invasive breast cancer overall (n = 37,861 cases) and by subtypes defined by ER status. Study-specific multivariable hazard ratios (HRs) were estimated and then combined using random-effects models. Results: Overall, no clear association was observed between the consumption of specific dairy foods, dietary (from foods only) calcium, and total (from foods and supplements) calcium, and risk of overall breast cancer. Although each dairy product showed a null or very weak inverse association with risk of overall breast cancer (P, test for trend >0.05 for all), differences by ER status were suggested for yogurt and cottage/ricotta cheese with associations observed for ER-negative tumors only (pooled HR = 0.90, 95% CI: 0.83, 0.98 comparing >= 60 g/d with = 25 g/d with Conclusion: Our study shows that adult dairy or calcium consumption is unlikely to associate with a higher risk of breast cancer and that higher yogurt and cottage/ricotta cheese intakes were inversely associated with the risk of ER-negative breast cancer, a less hormonally dependent subtype with poor prognosis. Future studies on fermented dairy products, earlier life exposures, ER-negative breast cancer, and different racial/ethnic populations may further elucidate the relation
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