3,090 research outputs found

    Divergent selection on feather pecking behaviour in laying hens (Gallus gallus domesticus)

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    A selection experiment was initiated in 1996 in which selection for (HP line) and against (LP line) feather pecking was performed. The foundation stock was a White Leghorn layer strain established in 1970 and maintained since then as a random bred control line at the Institute. Six hatches were produced over three generations. At the age of 68 wk (gen. 0, 1996), 35 wk (gen. 1, 1997), 30 wk (gen. 2, 1998), and 27 wk (gen. 3, 1999) female birds were transferred to observation pens and their feather pecking behaviour was recorded. In each generation, 30 females and 8 males were selected from approx. 200 females and 60 males. Selection criteria was breeding value estimated by animal model on the trait ‘number of bouts of feather pecking per bird per hour’. Feather pecking behaviour in adult hens was significantly higher in HP than in LP. In generation 2 the following was recorded: Bouts per bird per hour (3.10 versus 1.37, P<0.01), pecks per bird per hour (7.04 versus 3.58, P<0.05) and proportion of hens recorded feather pecking in the 180 minutes observation period (67 versus 56%, P<0.05). In generation 3 the following was recorded: Bouts per bird per hour (4.56 versus 0.63, P<0.001), pecks per bird per hour (13.9 versus 2.51, P<0.001) and proportion of hens recorded feather pecking in the 180 minutes observation period (75 versus 49%, P<0.001). In generation 3, plumage condition was better in LP on neck, breast, back, wings and tail, as well as overall (P<0.001). Body weight did not differ between lines in generation 2, but in generation 3, HP hens were on average heavier than LP hens at the age of 27 weeks (1435 g versus 1371 g, P<0.001)

    VARIANCE COMPONENTS AND SELECTION FOR FEATHER PECKING BEHAVIOR IN LAYING HENS

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    Variance components and selection response for feather pecking behaviour were studied by analysing the data from a divergent selection experiment. An investigation show that a Box-Cox transformation with power =-0.2 made the data be approximately normally distributed and fit best by the given model. Variance components and selection response were estimated using Bayesian analysis with Gibbs sampling technique. The total variation was rather large for the two traits in both low feather pecking line (LP) and high feather pecking line (HP). The standard deviation was about three times as large as the mean in the observed scale, and about the same value as the mean in the transformed scale. Based on the mean of marginal posterior distribution, in the Box-Cox transformed scale, heritability for number of feather pecking bouts (FP bouts) was 0.174 in line LP and 0.139 in line HP. For number of feather pecking pecks (FP pecks), heritability was 0.139 in line LP and 0.105 in line HP. No full-sib group effect and observing pen effect were found in the two traits. After 4 generations of selection, the total response for number of FP bouts in the transformed scale was 58% and 74% of the mean of the first generation in line LP and line HP, respectively. And the total response for number of FP pecks was 47% and 46% of the mean of the first generation in line LP and line HP, respectively. The total response in original scale in line HP was rather larger than that in line LP. These results show that the heritability for feather pecking behaviour is moderately low but the variation is large. And genetic improvement on feather pecking behaviour by selection is effective

    Visualising project interdependencies for enhanced project portfolio decision-making

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    Project management (PM) and project portfolio management (PPM) communities face challenges in the management of complex and highly interdependent project portfolios, as these interdependencies must be understood and managed for best project and portfolio outcomes. The research reported in this paper provides benefits to the global PM and PPM community by introducing a new tool and by providing insights into the factors affecting an organisationâs ability to understand project interdependencies (PI). Visual project mapping (VPM), the creation of graphical displays of projects and their interdependencies as a network of nodes and arrows, is shown to provide benefits by supporting communication and strategic portfolio decision making. The research also highlights the importance of the environment and culture as well as processes and tools and indicates that they work together to improve an organisationâs understanding of project portfolio interdependencie

    Global to local genetic diversity indicators of evolutionary potential in tree species within and outside forests

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    There is a general trend of biodiversity loss at global, regional, national and local levels. To monitor this trend, international policy processes have created a wealth of indicators over the last two decades. However, genetic diversity indicators are regrettably absent from comprehensive bio-monitoring schemes. Here, we provide a review and an assessment of the different attempts made to provide such indicators for tree genetic diversity from the global level down to the level of the management unit. So far, no generally accepted indicators have been provided as international standards, nor tested for their possible use in practice. We suggest that indicators for monitoring genetic diversity and dynamics should be based on ecological and demographic surrogates of adaptive diversity as well as genetic markers capable of identifying genetic erosion and gene flow. A comparison of past and present genecological distributions (patterns of genetic variation of key adaptive traits in the ecological space) of selected species is a realistic way of assessing the trend of intra-specific variation, and thus provides a state indicator of tree genetic diversity also able to reflect possible pressures threatening genetic diversity. Revealing benefits of genetic diversity related to ecosystem services is complex, but current trends in plantation performance offer the possibility of an indicator of benefit. Response indicators are generally much easier to define, because recognition and even quantification of, e.g., research, education, breeding, conservation, and regulation actions and programs are relatively straightforward. Only state indicators can reveal genetic patterns and processes, which are fundamental for maintaining genetic diversity. Indirect indicators of pressure, benefit, or response should therefore not be used independently of state indicators. A coherent set of indicators covering diversity–productivity–knowledge–management based on the genecological approach is proposed for application on appropriate groups of tree species in the wild and in cultivation worldwide. These indicators realistically reflect the state, trends and potentials of the world’s tree genetic resources to support sustainable growth. The state of the genetic diversity will be based on trends in population distributions and diversity patterns for selected species. The productivity of the genetic resource of trees in current use will reflect the possible potential of mobilizing the resource further. Trends in knowledge will underpin the potential capacity for development of the resource and current management of the genetic resource itself will reveal how well we are actually doing and where improvements are required

    Managing project interdependencies: exploring new approaches

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    The interdependencies between projects create complexities for the management of project portfolios within organisations. In times of uncertainty this challenge is even greater due to the difficulties in predicting the flow-on effects from changes to projects in the portfolio. Hence, in times of disruptive change a good understanding of project interdependencies is particularly important. This paper outlines two related studies that aim to improve the understanding and management of interdependencies within project portfolios. The paper first defines project portfolio management (PPM) and highlights its growing importance for optimising organisational outcomes, especially in dynamic environments. Project portfolio complexity and interdependencies between projects in a portfolio are then overviewed, highlighting the challenges that these interdependencies create for effective PPM, and introducing some of the methods used for understanding and managing these interdependencies including the dependency matrix and the related design structure matrix. Network analysis and mapping tools are then introduced and suggested as a novel method for improving understanding and managing project interdependencies. Finally, an example of the use of this type of method is presented and the current research projects are overviewed

    Load magnitude affects patellar tendon mechanical properties but not collagen or collagen cross-linking after long-term strength training in older adults

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    Abstract Background Regular loading of tendons may counteract the negative effects of aging. However, the influence of strength training loading magnitude on tendon mechanical properties and its relation to matrix collagen content and collagen cross-linking is sparsely described in older adults. The purpose of the present study was to compare the effects of moderate or high load resistance training on tendon matrix and its mechanical properties. Methods Seventeen women and 19 men, age 62–70 years, were recruited and randomly allocated to 12 months of heavy load resistance training (HRT), moderate load resistance training (MRT) or control (CON). Pre- and post-intervention testing comprised isometric quadriceps strength test (IsoMVC), ultrasound based testing of in vivo patellar tendon (PT) mechanical properties, MRI-based measurement of PT cross-sectional area (CSA), PT biopsies for assessment of fibril morphology, collagen content, enzymatic cross-links, and tendon fluorescence as a measure of advanced glycation end-products (AGEs). Results Thirty three participants completed the intervention and were included in the data analysis. IsoMVC increased more after HRT (+ 21%) than MRT (+ 8%) and CON (+ 7%) (p < 0.05). Tendon stiffness (p < 0.05) and Young’s modulus (p = 0.05) were also differently affected by training load with a reduction in CON and MRT but not in HRT. PT-CSA increased equally after both MRT and HRT. Collagen content, fibril morphology, enzymatic cross-links, and tendon fluorescence were unaffected by training. Conclusion Despite equal improvements in tendon size after moderate and heavy load resistance training, only heavy. load training seemed to maintain tendon mechanical properties in old age. The effect of load magnitude on tendon biomechanics was unrelated to changes of major load bearing matrix components in the tendon core. The study is a sub-study of the LISA study, which was registered at http://clinicaltrials.gov (NCT02123641) April 25th 2014

    Comparison of stimulation patterns for FES-cycling using measures of oxygen cost and stimulation cost

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    &lt;b&gt;Aim&lt;/b&gt;&lt;p&gt;&lt;/p&gt; The energy efficiency of FES-cycling in spinal cord injured subjects is very much lower than that of normal cycling, and efficiency is dependent upon the parameters of muscle stimulation. We investigated measures which can be used to evaluate the effect on cycling performance of changes in stimulation parameters, and which might therefore be used to optimise them. We aimed to determine whether oxygen cost and stimulation cost measurements are sensitive enough to allow discrimination between the efficacy of different activation ranges for stimulation of each muscle group during constant-power cycling. &lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt;&lt;p&gt;&lt;/p&gt; We employed a custom FES-cycling ergometer system, with accurate control of cadence and stimulated exercise workrate. Two sets of muscle activation angles (“stimulation patterns”), denoted “P1” and “P2”, were applied repeatedly (eight times each) during constant-power cycling, in a repeated measures design with a single paraplegic subject. Pulmonary oxygen uptake was measured in real time and used to determine the oxygen cost of the exercise. A new measure of stimulation cost of the exercise is proposed, which represents the total rate of stimulation charge applied to the stimulated muscle groups during cycling. A number of energy-efficiency measures were also estimated. &lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Average oxygen cost and stimulation cost of P1 were found to be significantly lower than those for P2 (paired &lt;i&gt;t&lt;/i&gt;-test, &lt;i&gt;p&lt;/i&gt; &lt; 0.05): oxygen costs were 0.56 ± 0.03 l min&lt;sup&gt;−1&lt;/sup&gt; and 0.61 ± 0.04 l min&lt;sup&gt;−1&lt;/sup&gt;(mean ± S.D.), respectively; stimulation costs were 74.91 ± 12.15 mC min&lt;sup&gt;−1&lt;/sup&gt; and 100.30 ± 14.78 mC min&lt;sup&gt;−1&lt;/sup&gt; (mean ± S.D.), respectively. Correspondingly, all efficiency estimates for P1 were greater than those for P2. &lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusion&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Oxygen cost and stimulation cost measures both allow discrimination between the efficacy of different muscle activation patterns during constant-power FES-cycling. However, stimulation cost is more easily determined in real time, and responds more rapidly and with greatly improved signal-to-noise properties than the ventilatory oxygen uptake measurements required for estimation of oxygen cost. These measures may find utility in the adjustment of stimulation patterns for achievement of optimal cycling performance. &lt;p&gt;&lt;/p&gt

    Determinants of Acceptance of Cervical Cancer Screening in Dar es Salaam, Tanzania.

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    To describe how demographic characteristics and knowledge of cervical cancer influence screening acceptance among women living in Dar es Salaam, Tanzania. Multistage cluster sampling was carried out in 45 randomly selected streets in Dar es Salaam. Women between the ages of 25-59 who lived in the sampled streets were invited to a cervical cancer screening; 804 women accepted and 313 rejected the invitation. Information on demographic characteristics and knowledge of cervical cancer were obtained through structured questionnaire interviews. Women aged 35-44 and women aged 45-59 had increased ORs of 3.52 and 7.09, respectively, for accepting screening. Increased accepting rates were also found among single women (OR 2.43) and among women who had attended primary or secondary school (ORs of 1.81 and 1.94). Women who had 0-2 children were also more prone to accept screening in comparison with women who had five or more children (OR 3.21). Finally, knowledge of cervical cancer and awareness of the existing screening program were also associated with increased acceptance rates (ORs of 5.90 and 4.20). There are identifiable subgroups where cervical cancer screening can be increased in Dar es Salaam. Special attention should be paid to women of low education and women of high parity. In addition, knowledge and awareness raising campaigns that goes hand in hand with culturally acceptable screening services will likely lead to an increased uptake of cervical cancer screening
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