118 research outputs found

    Effects of Cutting Height on Yield and Quality of Five Napier Cultivars

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    Results of this experiment revealed that dry matter yield of five Napier grass species increased with higher stubble and that a delay in closing date had produced a negative effect on regrowth for the following season, especially, when low cutting height had been imposed. The nitrogen and phosphorus percentage in leaf and stem materials were not affected by cutting height. Potassium percentage and NDF% were lower for herbage with 0 cm cutting height compared to 30 cm cutting. Among the different cutting intensities, 20 cm and 30 cm cutting height can be recommended through the growing season

    Cardiac Parasympathetic Reactivation in Elite Soccer Players During Different Types of Traditional High-Intensity Training Exercise Modes and Specific Tests: Interests and Limits

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    Background: The cardiac parasympathetic reactivation is currently used in soccer with a daily or weekly monitoring. However, previous studies have not investigated how this cardiac parasympathetic reactivation is in elite soccer players along different types of traditional high-intensity training exercise and specific tests. In this context, the present study aim to analyse it and to determine the interests and limits of this type of physiological information. Objectives: The present study aims to examine how different traditional training exercise modes affect the cardiac parasympathetic reactivation function in elite soccer players. Materials and Methods: Twenty-two international soccer players participating in UEFA Champion’s League took part in this study (age: 24.3 ± 4.2 years; height: 178.1 ± 6.2 cm; body mass: 80.3 ± 5.7 kg). Players performed different training methods including: short-duration intermittent exercises (INT) in-line and with changes of direction (COD) (10 - 10 seconds, 15 - 15 seconds, 30 - 30 seconds, e.g. an alternance of 10 - 10 seconds is 10 seconds of running according to the maximal aerobic speed (MAS) and 10-sec of recovery), INT including agility and technical skills (8 - 24-seconds), small-sided-games (SSGs) with and without goalkeepers (2 vs. 2, 3 vs. 3, 4 vs. 4), and repeated sprint ability (RSA) efforts (10 × 20 m, 10 × 30 m, 15 × 20 m). Heart rate (HR) decline was recorded 3 minutes after each exercise. Results: HR declines were greater after the RSA compared to SSGs (P < 0.001) and INT (P < 0.01), especially at 1 min post-exercise. In addition, when the analysis focused on each type of exercise, greater HR declines were observed in on-field players at 1 minute when there was: inclusion of goalkeepers in SSGs (for 2 vs. 2 and 3 vs. 3, P < 0.01); increase of sprint distances or number of sprint repetitions in RSA (P < 0.01); increase of intensity (% of maximal aerobic speed), and the use of COD or inclusion of technical skills during INT, especially for the 30 - 30-seconds. Conclusions: This study revealed that cardiac parasympathetic reactivation function varied after INT, RSA and SSG, but also according to the rules manipulation. Therefore, this study provides interesting information for the training monitoring and players’ recovery profile, with the aim of facilitating a more efficient planning and manipulation of training recovery strategies according to their fitness markers

    Heritability of and correlations among genotype-by-environment stability statistics for grain yield in bread wheat

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    Several genotype-by-environment stability measures are in use, but little information exists about their inheritance or genetic interrelationships. Among those measures in common use are the linear regression coefficient (b), deviations from regression (sb), coefficient of determination (R2), coefficient of phenotypic variation (CPV) and, more recently, interaction principal components (IPCA) of the additive main effect and multiplication interaction (AMMI) model. Because of the factorial structure of the data, the diallel cross is well suited to study these parameters and their relationship to quantitative traits. For this study a complete diallel cross, derived by mating eight lines (Buri, Kenya Chiruku, Edsa\Lira, Vee "S", Atilla, CY8801, F6603147 and Car853) from a broad based bread wheat breeding population, was grown for several growing seasons at two Ugandan locations (Kalengyere and Buginyanya), one of which was prone to yellow rust [Puccinia striiformis]. Stability parameters and grain yield were measured for each cross. CPV had the highest narrow-sense heritability (h2=0.522) followed by IPCA1 of the AMMI (h2=0.461). Lowest narrow-sense heritabilities were calculated for b and R2 (h2=0.150 and 0.100 respectively). There were high additive genetic correlations (rA) between grain yield and CPV (rA=-0.933), grain yield and IPCA1 (rA=0.707), and grain yield and IPCA2 (rA=0.751). The genetic association between CPV and IPCA1 was also high and negative (rA=-0.934). These results suggest that it may be possible to select simultaneously for high and stable grain yield in this broad-based bread wheat breeding pool by selecting outyielders that exhibit a low CPV

    Chronic CaMKII inhibition blunts the cardiac contractile response to exercise training

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    Activation of the multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays a critical role modulating cardiac function in both health and disease. Here, we determined the effect of chronic CaMKII inhibition during an exercise training program in healthy mice. CaMKII was inhibited by KN-93 injections. Mice were randomized to the following groups: sham sedentary, sham exercise, KN-93 sedentary, and KN-93 exercise. Cardiorespiratory function was evaluated by ergospirometry during treadmill running, echocardiography, and cardiomyocyte fractional shortening and calcium handling. The results revealed that KN-93 alone had no effect on exercise capacity or fractional shortening. In sham animals, exercise training increased maximal oxygen uptake by 8% (p < 0.05) compared to a 22% (p < 0.05) increase after exercise in KN-93 treated mice (group difference p < 0.01). In contrast, in vivo fractional shortening evaluated by echocardiography improved after exercise in sham animals only: from 25 to 32% (p < 0.02). In inactive mice, KN-93 reduced rates of diastolic cardiomyocyte re-lengthening (by 25%, p < 0.05) as well as Ca2+ transient decay (by 16%, p < 0.05), whereas no such effect was observed after exercise training. KN-93 blunted exercise training response on cardiomyocyte fractional shortening (63% sham vs. 18% KN-93; p < 0.01 and p < 0.05, respectively). These effects could not be solely explained by the Ca2+ transient amplitude, as KN-93 reduced it by 20% (p < 0.05) and response to exercise training was equal (64% sham and 47% KN-93; both p < 0.01). We concluded that chronic CaMKII inhibition increased time to 50% re-lengthening which were recovered by exercise training, but paradoxically led to a greater increase in maximal oxygen uptake compared to sham mice. Thus, the effect of chronic CaMKII inhibition is multifaceted and of a complex nature

    The Role of Canine Distemper Virus and Persistent Organic Pollutants in Mortality Patterns of Caspian Seals (Pusa caspica)

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    Persistent organic pollutants are a concern for species occupying high trophic levels since they can cause immunosuppression and impair reproduction. Mass mortalities due to canine distemper virus (CDV) occurred in Caspian seals (Pusa caspica), in spring of 1997, 2000 and 2001, but the potential role of organochlorine exposure in these epizootics remains undetermined. Here we integrate Caspian seal mortality data spanning 1971-2008, with data on age, body condition, pathology and blubber organochlorine concentration for carcases stranded between 1997 and 2002. We test the hypothesis that summed PCB and DDT concentrations contributed to CDV associated mortality during epizootics. We show that age is the primary factor explaining variation in blubber organochlorine concentrations, and that organochlorine burden, age, sex, and body condition do not account for CDV infection status (positive/negative) of animals dying in epizootics. Most animals (57%, n = 67) had PCB concentrations below proposed thresholds for toxic effects in marine mammals (17 ÎŒg/g lipid weight), and only 3 of 67 animals had predicted TEQ values exceeding levels seen to be associated with immune suppression in harbour seals (200 pg/g lipid weight). Mean organonchlorine levels were higher in CDV-negative animals indicating that organochlorines did not contribute significantly to CDV mortality in epizootics. Mortality monitoring in Azerbaijan 1971-2008 revealed bi-annual stranding peaks in late spring, following the annual moult and during autumn migrations northwards. Mortality peaks comparable to epizootic years were also recorded in the 1970s-1980s, consistent with previous undocumented CDV outbreaks. Gompertz growth curves show that Caspian seals achieve an asymptotic standard body length of 126-129 cm (n = 111). Males may continue to grow slowly throughout life. Mortality during epizootics may exceed the potential biological removal level (PBR) for the population, but the low frequency of epizootics suggest they are of secondary importance compared to anthropogenic sources of mortality such as fishing by-catch

    YAM BEAN (Pachyrhizus spp.) VARIETY TRIALS IN TONGA, SOUTH PACIFIC: FRESH TUBER YIELDS, DRY MATTER AND NITROGEN CONTENTS

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    A total of 16 accessions of Yam Bean (14 Pachvrhizus erosus. 1 ÂŁ. ahipa and 1 P. tuberosus) were tested in a yield trial in Tonga. In addition 29 other accessions representing four different species of-Yam Bean (24 P. erosus. 2 P. ahipa. 2 P. tuberosus and 1 P. panamensis) were observed in multiplication plots. In the yield trials fresh weight tuber yields were up to 72 tons/ha. Dry matter percentages ranged from 8.0 to 20.8 with dry matter yields ranging from 1,13 0 Kg/ha to 7,4 60 Kg/ha. Nitrogen contents of raw peeled tubers were between 0.82 to 1.57% giving crude protein yields of 71-540 Kg/ha, or about twice as much as sweet potatoes (Ipomoea spp.) when grown under similar conditions in Tonga
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