197 research outputs found

    Dispersal of _Aedes aegypti_: field study in temperate areas and statistical approach

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    We studied the dispersion of _Aedes aegypti_ during egg laying in natural conditions. Two independent experiments involving mosquitoes dispersing from urbanization towards adjacent un-urbanized areas were carried out and analyzed in statistical terms. We find relations between stochastic variables related to the egg laying mosquito activity (ELMA), useful to assess dispersion probabilities, despite the lack of knowledge of the total number of ovipositions in the zone. We propose to evaluate the activity as minus the logarithm of the fraction of negative ovitraps at different distances from buildings. We also estimate the average number of eggs laid per oviposition using a regression between the ELMA and the number of eggs found. Three zones with different oviposition activity were determined: a corridor surrounding the urbanized area, a second region between 10m and 25m and the third region extending from 30m to 45m from the urbanization. The landscape (plant cover) and the human activity in the area appear to have an influence in the dispersal of _Aedes aegypti_

    Assessment of Structural Traits and Management Related to Dairy Herds in the Peri-urban Area of Bobo Dioulasso (South West of Burkina Faso)

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    To define mean herd size, structural traits, animal sourcing and use, management and aspects related to the milk production, 118 dairy herds, involved in a FAO dairy development project were studied. The mean herd size after allocation to clusters: Small (≤38 heads), Medium (>38, ≤61 heads) and Large (>61 heads) was 52.8±25.8, ranging from 7 to 134 heads of cattle. The following genotypes: Cross bred (CR) 58.8%, Zebu (ZB) 23.2% and Taurine cattle (TA) 18.0% which were not uniformly distributed neither across nor within herds were identified. Sex ratio was two thirds of females (70.6%), one third of males (28.1%) and a low proportion (1.3%) of castrated males. No mature TA males compared to 53.3% of the male ZB and 31.4% of the male CR, were indicated as potential sires. Investments in purchase of animals were higher in Small than in Medium and Large herds; of all purchased sires 53.8% were found in Small herds vs. 28.2% and 18.0% in Medium and Large. Herd property was equally distributed between single (56.8%) and multi property (43.2%). There was more manpower available per 100 cows in Small, being almost double and triple than in Medium and Large herds. Although milk extracted, was similar in all clusters averaging 2.4±0.5 litres/day/cow, milk off take rate, due to higher proportion of lactating cows, appeared higher in Small herds

    Contribution to our knowledge of the physiology and metabolism of endurance horses

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    Effect of slaughter age on meat qualitative traits of veals calves

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    Scopo del presente lavoro è stato quello di verificare alcune caratteristiche organolettiche e chimico bromatologhe della carne di 15 vitelli di razza Frisona. I vitelli sono stati macellati a 140, 160 e 190 giorni. I parametri analizzati non sono stati significativamente influenzati dall'età di macellazione se non per una riduzione del tenore proteico della sostanza secca a 160 giorni. Pertanto la scelta dell'età di macellazione, per il periodo studiato, può essere fatta sulla base di criteri di natura economica piuttosto che riferita ad aspetti qualitativi della carn

    Daily Rhythms of Serum Vitamin D-Metabolites, Calcium and Phosphorus in Horses

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    Many physiological processes of domestic animals exhibit daily rhythmicity. The goal of the present study was to investigate the daily rhythms of calcium, inorganic phosphorus and 24,25-(OH)2-D3, 25-(OH)-D3 and 1,25-(OH)2-D3 in the blood serum of horses. Five Thoroughbred mares from the same farm, clinically healthy and placed in individual stalls, at the same environmental temperature and photoperiod were used. For 30 days prior to the study, the animals underwent the same pattern of daily activity. Blood samples were collected at 4 h-intervals for 48 consecutive h, starting at 08:00 h of the first day and finishing at 04:00 h of the second day, via intravenous cannula inserted into the jugular vein. Each individual sample was assessed for serum concentration of calcium and inorganic phosphorus by means of a UV spectrophotometric test, and serum concentration of 24, 25-(OH)-D3, 25-(OH)-D3, and 1,25-(OH)2-D3 were assessed by means of HPLC method. Data analysis was conducted by one-way repeated measures analysis of variance (ANOVA) and by the single cosinor method. ANOVA showed a significant effect of time on all the variables studied (p < 0.0001) and post-hoc test (SNK) showed significant differences (p < 0.001) comparing all the time intervals of 4 h, on either day. The application of the periodic model and the statistical analysis of the cosinor procedure allowed defining the periodic variables and their acrophases (expressed in hours) during the 2 days of monitoring. Calcium showed diurnal acrophases at 15:00 h for the 1st day and at 15:48 for the 2nd day; inorganic phosphorus showed diurnal coincident acrophases at 14:32 h both for the 1st and 2nd day and 25-(OH)-D3 showed diurnal acrophases at 14:08 h for the 1st day and at 15:04 h for the 2nd day. The results obtained could be useful for standardizing blood sampling according to the time of day and for optimizing the administration of these substances according to their circadian or other rhythms

    Agrochemical contamination of honey and bee bread collected in the piedmont region, Italy

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    This study shows the results of a local biomonitoring plan developed by a regional beekeeping association, Aspromiele, in several areas of Piedmont (Italy), in order to understand the status of contamination from pesticides present in the environment and eventually to evaluate their impact on apiculture. Glyphosate was the most abundant chemical found in the bee bread and honey samples. The other pesticides detected at lower concentrations and minor frequency were mandipropamid, tau-fluvalinate, metalaxil and spiroxamine. Even if in the present study the pesticides found in the bee bread and honey were limited to a few molecules, it is important to highlight that the presence of glyphosate could represent a hazard to bees. Honeybees are the main pollinators in agricultural ecosystems, and thus appropriate environmental management could lead to a reduction in the impact of these chemicals on bees and other beneficial insects

    Effects of low doses of dexamethasone on productive traits and meat quality of veal calves

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    An experimental administration of dexamethasone was carried out on 15 veal calves in order to assess the rĂ´le of low doses of exogenous glucocorticoids on productive traits and meat quality. Three groups, of five veal calves each, were formed : one group received oral dexamethasone (0.4 mg per calf per day for 25 days), another intramuscular (i. m.) dexamethasone (2 mg at days 14 and 21), and the third was the control. Calves were slaughtered at 165 days of age (day 31). Food conversion ratio (FCR), hot dressing percentage (HDP), chilled dressing percentage (CDP) and shrinkage were determined. From all carcasses, samples of m. longissimus thoracis (between the 8th and 10th rib) were taken in order to evaluate the chemical composition and some organoleptic characteristics : meat colour, water-holding capacity and tenderness. The animals treated with oral dexamethasone showed the lowest daily weight gain (P < 0.05) and the poorest FCR (P < 0.05). Hot dressing percentage, cold dressing percentage and shrinkage were not affected by the oral treatment. The i. m. injections of dexamethasone did not influence the overall performance. Muscle chemical composition and pH were not affected by the treatments; the meat of calves treated with oral dexamethasone was significantly lighter (P < 0.05) and tended to be paler, while i. m. treatment induced intermediate characteristics. The shear force of the meat was rather low. Shear force of cooked meat from animals treated with dexamethasone (both oral and i. m.) was significantly lower than the control (P < 0.05). Treatment with dexamethasone i. m. induced a decrease in water-holding capacity; the oral treatment had no effect on this parameter

    Management of feline hyperthyroidism and the need to prevent oxidative stress: What can we learn from human research?

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    Feline hyperthyroidism is a clinical syndrome related to an excessive production of thyroid hormones, and it is considered as a spontaneous animal model for human thyrotoxicosis. Many shared features between the feline and the human disease have been identified so far, including pathogenesis, clinical signs, and treatment options. Although methimazole is considered the first-choice drug in both species, several side effects have been described. Furthermore, methimazole could interfere with the oxidative status, already perturbated by the disease. It has been reported in humans that dietary management, mainly through antioxidant supplementation, could mitigate this oxidative burden. The purpose of the review is to describe current therapeutic options in the course of feline hyperthyroidism and to summarize the state of the art relationship between dietary antioxidants administration and the reduction of methimazole side-effects in humans to support the use of this approach also in cats

    Innovations in Educational Research and Teaching of Experimental Calculus

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    For several decades, there have been a varying number of books on Calculus following the classic line of mathematical thought, where Mathematics is taught for everybody by means of rigorous definitions, theorems, and carefully detailed and extensive demonstrations. For mathematical education into the XXI Century the students need to achieve ability in handling of present mathematical tools and concepts from the beginning of their courses. These needs can be achieved today by means of a paradigmatic change in the focus of mathematics teaching: to learn to develop ideas and to experiment and test those ideas in such way that students can verify their own inferences. In this paper we report an educational research in teaching and learning functions models according to a new paradigm in hands-on experimental mathematics, with applications in the real world, i.e. sciences and engineering by using Computer Algebra Systems. The study of functions is presented, focused into the framing of Exploratory Learning Systems, where students learn by means of the action and their participation in it. It is designed for teachers working together with students in a computer laboratory like hands-on workshops-type activities on other sciences. In this way students have a more “alive”, “realistic” and “accessible” touch in Calculus
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