913 resultados para Effect of the pasture supplementation strategy in the growing period on performance


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BACKGROUND AND OBJECTIVES: College students and young adults are experiencing the greatest increases in rates of obesity, and 20% of college students are classified as obese. The objective of this study was to compare changes and rates of change in body weight and body composition between the freshman academic year and the summer after the freshman year among female college students. METHODS: Participants were recruited early in their freshman year of college to participate in a prospective longitudinal study examining changes in body weight and composition over the college years. Height and weight were measured, and body composition was assessed using dual energy x-ray absorptiometry (DEXA) at the beginning and end of the freshman year. Upon return from the summer for their sophomore year, participants returned to have all measurements repeated. Sixty-nine female participants completed all three visits. RESULTS: Body weight increased 1.3 kg during the academic period and an additional 0.1 kg during the summer period. Body mass index (BMI) increased between the first two visits but did not change between the last two visits. However, percent fat increased at each visit. Fat-free mass significantly increased 0.5 kg over the academic year but decreased by 1.1 kg over the summer (p<0.05). Greater rates of change were detected in percent fat, fat-free mass, and BMI during the summer compared with the academic year (p<0.05). CONCLUSIONS: Differences in body composition between the academic and summer periods may reflect changes in living situations between these periods. Unfavorable changes during the summer suggest the need to promote healthy lifestyles to freshman women before they leave campus for the summer

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Tick infestation occurs over 1.3 x 106 km2 in northern Australia. It has been difficult to estimate the economic effects of ticks due to a lack of information on their effects on growth and reproduction (Anon 1975). 12th Biennial Conference. February 1978. Melbourne, Victoria

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In order to assess the structural reliability of bridges, an accurate and cost effective Non-Destructive Evaluation (NDE) technology is required to ensure their safe and reliable operation. Over 60% of the Australian National Highway System is prestressed concrete (PSC) bridges according to the Bureau of Transport and Communication Economics (1997). Most of the in-service bridges are more than 30 years old and may experience a heavier traffic load than their original intended level. Use of Ultrasonic waves is continuously increasing for (NDE) and Structural Health Monitoring (SHM) in civil, aerospace, electrical, mechanical applications. Ultrasonic Lamb waves are becoming more popular for NDE because it can propagate long distance and reach hidden regions with less energy loses. The purpose of this study is to numerically quantify prestress force (PSF) of (PSC) beam using the fundamental theory of acoustic-elasticity. A three-dimension finite element modelling approach is set up to perform parametric studies in order to better understand how the lamb wave propagation in PSC beam is affected by changing in the PSF level. Results from acoustic-elastic measurement on prestressed beam are presented, showing the feasibility of the lamb wave for PSF evaluation in PSC bridges.

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An attempt was made to feed bioencapsulate Lactobacillus sp. in live fish food organism Tubifex for use in the culture of gold fish Carassius auratus. The C. auratus fries when fed with bioencapsulated Lactobacillus sp. in Tubifex showed significant improvement in total wet weight gain (p<0.007) and FCR (p<0.01) compared to control. The specific growth rale and mean survival were slightly higher, although insignificantly (p>0.05) in bioencapsulated Tubifex fed group. None of the bacteriological parameters of the fish gut between the experimental and control groups differed significantly (p>0.05). Lactobacillus sp. was recorded at a level of log 5.11/g on the 90th day of experimentation. When the experimental C. auratus fries were infected with Pseudomonas fluorescents, the bioencapsulated Tubifex fed group resisted the infection. The survival was significantly higher (p<0.05) in bioencapsulated Tubifex fed group (44%) than in control (22%). The C. auratus fed with bioencapsulated Tubifex showed less (55%) signs of tail/fin rot. Likewise, a significant improvement in total wet weight gain (p<0.009), FCR (p<0.01) and SGR (p<0.04) of C. auratus brooder fed with bioencapsulated Tubifex was seen compared to control group fed with depurated Tubifex.

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Although the bactericidal effect of copper has been known for centuries, there is a current resurgence of interest in the use of this element as an antimicrobial agent. During this study the use of dendritic copper microparticles embedded in an alginate matrix as a rapid method for the deactivation of Escherichia coli ATCC 11775 was investigated. The copper/alginate produced a decrease in the minimum inhibitory concentration from free copper powder dispersed in the media from 0.25 to 0.065 mg/ml. Beads loaded with 4% Cu deactivated 99.97% of bacteria after 90 minutes, compared to a 44.2% reduction in viability in the equivalent free copper powder treatment. There was no observed loss in the efficacy of this method with increasing bacterial loading up to 10(6) cells/ml, however only 88.2% of E. coli were deactivated after 90 minutes at a loading of 10(8) cells/ml. The efficacy of this method was highly dependent on the oxygen content of the media, with a 4.01% increase in viable bacteria observed under anoxic conditions compared to a >99% reduction in bacterial viability in oxygen tensions above 50% of saturation. Scanning electron micrographs (SEM) of the beads indicated that the dendritic copper particles sit as discrete clusters within a layered alginate matrix, and that the external surface of the beads has a scale-like appearance with dendritic copper particles extruding. E. coli cells visualised using SEM indicated a loss of cellular integrity upon Cu bead treatment with obvious visible blebbing. This study indicates the use of microscale dendritic particles of Cu embedded in an alginate matrix to effectively deactivate E. coli cells and opens the possibility of their application within effective water treatment processes, especially in high particulate waste streams where conventional methods, such as UV treatment or chlorination, are ineffective or inappropriate.