17 resultados para Cote énergétique

em University of Queensland eSpace - Australia


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Treatment of cut freesia var. Cote d'Azur flowers with methyl jasmonate (MeJA, 0.1 mu l MeJA l(-1)) vapour suppressed petal specking caused by Botrytis cinerea infection. MeJA efficacy was concentration and incubation temperature dependent. Disease severity, lesion numbers and lesion diameters decreased with increasing MeJA concentration from 0.025 to 0.1 mu l MeJA l(-1). However, there were no significant (P > 0.05) differences among MeJA concentrations examined. MeJA was more effective in reducing B. cinerea flower specking at 20 degrees C than at 12 degrees C. MeJA treatment was ineffective at 5 degrees C. At 20 degrees C, MeJA treatment at 0.1 mu l MeJA l(-1) reduced disease severity, lesion numbers and lesion diameters by 58, 50 and 48%, respectively, as compared to untreated controls. In a repeat experiment, disease severity, lesion numbers and lesion diameters on MeJA vapour treated flowers after 12 h of incubation were reduced by 68, 56 and 50%, respectively. MeJA did not exert direct antifungal activity in-vitro, suggesting that treatment in-vivo reduced B. cinerea-induced flower specking by induction of host defence responses. MeJA at 0.1 mu l MeJA l(-1) significantly (P < 0.05) increased vase life of cut freesia flowers and delayed senescence judged by lower wilt scores and higher fresh weights as compared to untreated controls. (c) 2005 Elsevier B.V. All rights reserved.

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This paper proposes a three-step method of evaluating high performance coaches involving feedback from the athletes. First, data are collected using an instrument such as the Coaching Behavior Scale for Sport (CBS-S: Cote, Yardley, Hay, Sedgwick, & Baker, 1999). Second, a summary report is prepared with descriptive information regarding the frequency of behaviors demonstrated by the coach that can be compared to previous results or to a criterion measure. The third step involves appropriate personnel reviewing the report and subsequently providing guidance for individual coach development. This three-step appraisal method provides useful evaluative feedback to coaches and has been used in several sport programs in Canada, the United States, and Australia.

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Despite the success of extensive control measures that have been implemented in China for over 50 years, the number of individuals infected with Schistosoma japonicum remains high in the existing endemic areas. A variance components analysis was undertaken to estimate the heritable and environmental components that contribute to S. japonicum infection in the Poyang Lake region of Jiangxi Province, PR China. The total target population was 3148 from four separate administrative villages. Two thousand seven hundred and five of these comprised 400 families ranging in size from 3 to 188. After adjustments were made for gender, water contact and past history of having had schistosomiasis, the heritable component was estimated to account for as much as 58% of the phenotype variation under the polygenic model. Household was not shown to be an important environmental factor. Incorporating village effects indicated that the results were valid for the total population. We conclude that genetic heritability in this region is high and plays an important role in determining risk of infection with S. japonicum. (c) 2005 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

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Compounds that activate host plant defence responses potentially offer socio-environmentally sound alternative methods for disease control. In a series of glasshouse trials over 2 years, pre-harvest sprays with acibenzolar-S-methyl (ASM) and methyl jasmonate (MeJA) were tested for suppression of post-harvest infection of cut Freesia hybrida L. flowers by Botrytis cinerea. For the ASM treatments, variability in reducing the incidence of B. cinerea disease was observed between years freesia varieties, incubation temperatures and ASM concentrations. In the first year, the greatest reductions in lesion numbers on ASM-treated var. 'Cote d'Azur' were recorded using 2.86 mM ASM. For three different post-harvest temperature regimes, the relative reductions in lesion numbers, compared to untreated controls, were 45% at 5 degrees C, 40% at 12 degrees C and 30% at 20 degrees C, respectively. In the second year, lesion numbers were most reduced using 1.43 mM ASM to treat freesia var. 'Dukaat' flowers. Here, the relative reductions were to 44% at 5 degrees C, 26% at 12 degrees C and 51% at 20 degrees C. MeJA treatments were, in general, more consistently effective than ASM treatments in reducing lesion numbers and lesion diameters on cut freesia flowers. MeJA-treated (0.2 mM) freesia flowers (var. 'Dukaat') incubated at 20 degrees C showed relative reductions of 62%, and 45% for lesion number and lesion diameter, respectively. The differing efficacy between ASM and MeJA treatments could be attributed to their differential abilities to induce the salicylic acid (SA)-mediated vs. the jasmonic acid (JA)-mediated host defence pathways, respectively.

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In this study, we assessed whether contextual factors related to where or when an athlete is born influence their likelihood of playing professional sport. The birthplace and birth month of all American players in the National Hockey League, National Basketball Association, Major League Baseball, and Professional Golfer's Association, and all Canadian players in the National Hockey League were collected from official websites. Monte Carlo simulations were used to verify if the birthplace of these professional athletes deviated in any systematic way from the official census population distribution, and chi-square analyses were conducted to determine whether the players' birth months were evenly distributed throughout the year. Results showed a birthplace bias towards smaller cities, with professional athletes being over-represented in cities of less than 500,000 and under-represented in cities of 500,000 and over. A birth month/relative age effect (in the form of a distinct bias towards elite athletes being relatively older than their peers) was found for hockey and baseball but not for basketball and golf. Comparative analyses suggested that contextual factors associated with place of birth contribute more influentially to the achievement of an elite level of sport performance than does relative age and that these factors are essentially independent in their influences on expertise development.

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'Specking' on harvested freesia (Freesia hybrida) flowers is a problem worldwide. The disease is caused by the fungal pathogen Botrytis cinerea. This disease symptom detracts from appearance and reduces marketability of the flowers. Unlike other important cut flower crops (e.g. gerbera), the mode of infection and epidemiology of postharvest freesia flower specking caused by B. cinerea has not been reported. Epidemiological studies were carried out under simulated conditions typical of those occurring during postharvest handling of freesia flowers. Infection of freesia flowers by B. cinerea occurred when a conidium germinated, formed a germ tube(s) and penetrated epidermal cells. Fungal hyphae then colonised adjacent cells, resulting in visible lesions. Different host reactions were observed on freesia 'Cote d'Azur' petals at 20 degrees C compared to 5 degrees C. The infection process was relatively rapid at 20 degrees C, with visible lesions produced within 7 h of incubation. However, lesion expansion ceased after 24 h of incubation. Infection was slower at 5 degrees C, with visible lesions produced after 48 h of incubation. However, lesion development at 5 degrees C was continuous, with lesions expanding over 4 days. Light microscopy observations revealed increased host defence reactions during infection. These reactions involved production of phenolic compounds, probably lignin and/or callose, around infection sites. Such substances may play a role in restricting petal colonisation and lesion expansion. Disease severity and lesion numbers on freesia flowers incubated at 12 degrees C were higher, but not significantly higher (P > 0.05), than on those incubated at 20 degrees C. Disease severity and progression were differentially mediated by temperature and relative humidity (R. H.). Infection of freesia flowers was severe at 100% R. H. for all three incubation temperatures of 5, 12 and 20 degrees C. In contrast, no lesions were produced at 80 to 90% R. H. at either 5 or 20 degrees C.

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