43 resultados para Tree traits

em Deakin Research Online - Australia


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Sperm number is often a good predictor of success in sperm competition; however, it has become increasingly clear that, for some species, variation in probability of paternity cannot be explained by sperm number alone. Intraspecific variation in ejaculate characteristics, such as the number of viable sperm and sperm longevity, may play an equally important role in determining fertilization success. Here, we assess variation among ejaculates in three factors that may contribute to fertilization success (number of sperm per ejaculate, viability, and longevity), in a population of Peron’s tree frog (Litoria peronii). We detected large variation among males in the number of sperm per ejaculate and the proportion of viable sperm within ejaculates, which could not be explained by variation in either male size or body condition. However, the proportion of viable sperm released by males increased over the season. Finally, we assessed sperm longevity (proportion viable sperm determined using a dual-fluorochrome vital dye) at two different temperatures. At 23°C, on average, 75% of sperm remained viable after 2 h, but there were significant differences amongst males with the percentage of viable sperm ranging from 43% to 95%. For sperm incubated at 4°C, ejaculates varied fivefold in sperm longevity with some males having 50% viable sperm after 5 days. Our data suggest that ejaculate characteristics (sperm number, viability, and longevity) vary widely in Peron’s tree frog and may therefore play an important role in determining siring success both in the presence and absence of sperm competition. We discuss the results in relation to selection on ejaculate traits via natural and sexual selection in this and other amphibians.

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Animal personality traits such as boldness, activity and aggressiveness have been described for many animal species. However, why some individuals are consistently bolder or more active than others, for example, is currently obscure. Given that life-history tradeoffs are common and known to promote inter-individual differences in behavior, we suggest that consistent individual differences in animal personality traits can be favored when those traits contribute to consistent individual differences in productivity (growth and/or fecundity). A survey of empirical studies indicates that boldness, activity and/or aggressiveness are positively related to food intake rates, productivity and other life-history traits in a wide range of taxa. Our conceptual framework sets the stage for a closer look at relationships between personality traits and life-history traits in animals.

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The conservation of roosting and nesting resources is of critical concern for many hollow-dependent species around the world. We investigated the nest-tree requirements of the threatened brush-tailed phascogale (Phascogale tapoatafa) in a highly cleared agricultural landscape in south-eastern Australia. We documented the physical characteristics of selected nest trees and describe the spatial and temporal patterns of nest-tree use as revealed by radio-tracking. Nine phascogales (seven females, two males) were radio-tracked between March and July 1999 in an area where most woodland habitat is confined to linear strips along roads and streams or small patches and scattered trees in cleared farmland. Female phascogales were monitored for 13–35 days over periods of 5–15 weeks and two males were monitored for 2 and 9 days respectively. A total of 185 nest-tree fixes was collected and all nests occupied by phascogales were in standing trees. Eighty-three nest trees were identified, ranging in diameter at breast height (dbh) from 25 to 171 cm, with a mean dbh for the trees used by each individual phascogale of >80 cm. Phascogales did not discriminate between canopy tree species in selecting nest trees, but showed highly significant selection for trees in the largest size class. All individuals used multiple nest trees, with the seven females occupying an average of 11.4 nest trees from a mean of 25 diurnal locations. The number of nest trees continued to increase throughout the study, suggesting that more would be identified during a longer or more intensive study. Occupied nest trees were located throughout each individual’s home range, highlighting the importance of a continuous spatial distribution of suitable nest trees across the landscape. Nest trees were also located in adjacent farmland up to 225 m from roadside vegetation, demonstrating the value that scattered clumps and even single trees in farmland can have for wildlife conservation.

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A general rooted tree drawing algorithm is designed in this paper. It satisfies the basic aesthetic criteria and can be well applied to binary trees. Given an area, any complex tree can be drawn within the area in users' favorite styles. The algorithm is efficient with O(LxNxlogN) time complexity and self-adaptive as well.

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This study uses a hierarchical approach to build a model of the relationships between Consumer Need for Uniqueness (CNFU), Consumer Novelty Seeking (CNS), and a behavioural outcome, media consumption and information exposure. The study finds that those consumers who have a need for uniqueness are high in consumer novelty seeking tendencies. Subsequently, these consumers are found to have higher information exposure by consuming more media.

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The interplay between stable personality characteristics and environmental factors is emphasised in most contemporary approaches to individual differences. This interaction appears to be important in understanding the development of substance use and misuse. Impulsivity related personality traits such as sensation-seeking, novelty seeking, reward-sensitivity and behavioural disinhibition, are strongly linked to adolescent and adult substance use and misuse. The role of anxiety-related traits, in the development of substance misuse is less clear. Nonetheless, anxiety disorders are very common amongst adult substance misusers and almost certainly play a critical role in the maintenance of a substance use disorder and influence treatment effectiveness. The data suggest that personality influences treatment outcomes and yet these individual differences are generally not addressed in treatment. We argue in this review that interventions which are matched to these relevant personality traits may improve treatment outcomes for substance misusers. [Staiger PK, Kambouropoulos N, Dawe S. Should personality traits be considered when refining substance misuse treatment programs?

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The symptoms of problem drinking and disordered eating were studied independently in relation to sex-role traits and also for evidence of comorbidity in a student sample of 217 women. The participants completed surveys that assessed positive and negative sex-role traits, reported drinking levels, alcohol dependence, problem drinking, bulimic symptoms, dietary restraint, and drive for thinness. Eating symptoms were related to both the negative and positive traits of Femininity, but self-descriptions involving negative traits (passivity, dependence, unassertiveness, etc.) showed the strongest relationship. High scores on identification with the traits typically labelled as Masculinity were related to drinking but there was an important difference between drinking per se (which was related to Positive Masculinity) and drinking found to be associated with drinking problems, which was related to Negative Masculinity (aggression, showing-off, rudeness, etc.). Feminine traits were also related to drinking. Low identification with the traits of Negative Femininity was associated with non-problem drinking, whereas low identification with the traits of Positive Femininity were associated with problem-related drinking. Young women who displayed comorbid symptoms described themselves by a high identification with the traits of both Negative Masculinity and Negative Femininity. It was argued that comorbidity reveals a more extreme form of the sex-role conflict previously described in relation to disordered control over both eating and drinking when considered independently.

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Cluster computation has been used in the applications that demand performance, reliability, and availability, such as cluster server groups, large-scale scientific computations, distributed databases, distributed media-on-demand servers and search engines etc. In those applications, multicast can play the vital roles for the information dissemination among groups of servers and users. This paper proposes a set of novel efficient fault-tolerant multicast routing algorithms on hypercube interconnection of cluster computers using multicast shared tree approach. We present some new algorithms for selecting an optimal core (root) and constructing the shared tree so as to minimize the average delay for multicast messages. Simulation results indicate that our algorithms are efficient in the senses of short end-to-end average delay, load balance and less resource utilizations over hypercube cluster interconnection networks.

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This experiment was conducted to examine the effect of feeding small, isoenergetic amounts of supplements containing high protein and functional lipid components, rather than the greater amounts of cereal and/or legume grains usually fed during the dry season in Australia, on dry matter intake (DMI), growth performance, plasma metabolites, and fat deposition in lambs consuming low quality roughage. Thirty two crossbred wether lambs ([Merino × Border Leicester] × Poll Dorset) were divided into four groups by stratified randomization according to liveweight (26–33 kg). After a 7-day adaptation to a hay diet (lucerne hay:oaten hay; 30:70), lambs were allocated to four treatments consisting of (1) basal diet of lucerne hay:oat hay (20:80; metabolizable energy (ME) = 7.0 MJ/kg DM), Basal; (2) basal + canola meal (84 g per day), CM; (3) basal + soymeal (75 g per day), SM; or (4) basal + fishmeal (80 g per day), FM. Daily hay and supplement DMI, and weekly liveweight were recorded during a 53-day experimental study. Blood samples were taken on day 1 and pre- and post-feeding on days 30 and 53 to measure changes in plasma glucose and plasma urea nitrogen (PUN) concentration. At the end of the experiment, lambs were slaughtered and hot carcass weight (HCW) recorded; cold carcass fatness (total muscle and adipose tissue depth at 12th rib, 110 mm from midline; GR) was determined at 24 h postmortem. Total DMI was increased (P < 0.001) in CM, SM and FM treatments, but basal hay DMI intake was only increased (P < 0.01) in CM and FM treatments compared with Basal treatment. This resulted in significant (P < 0.01) increases in metabolizable energy (ME) and crude protein (CP) intakes in all supplemented treatments, with the highest intakes recorded in the FM treatment. Liveweight gain (LWG) was significantly increased in CM and SM (P < 0.05) and FM (P < 0.01) treatments but HCW was significantly (P < 0.01) heavier slaughter only in the FM treatment. Feed conversion efficiency (P < 0.001) and GR fat at depth (P < 0.05) was reduced in all supplement treatments compared with Basal. Plasma glucose concentration was significantly (P < 0.05) increased after feeding in all treatments but there was no treatment effect. PUN was significantly increased over time in the supplemented treatments compared with the Basal treatment; there was no significant difference between supplement treatments by day 53. Results show that feeding small amounts of high protein and lipid-containing supplements improves production responses and are beneficial in producing carcasses with more lean compared with carcasses from lambs fed a low quality hay diet.


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In a previous study we showed that feeding fish meal significantly increased muscle long chain n-3 fatty acids (FA) and hot carcass weight. In this study we compared the effect of fish meal and fish oil on increasing muscle long-chain FA. We also investigated whether the increase in carcass weight was due to the effect of dietary enrichment of muscle long-chain n-3 FA on muscle membrane phospholipids and(or) to rumen by-pass protein provided by fish meal. Forty crossbred ([Merino x Border Leicester] x Poll Dorset) wether lambs between 26 and 33 kg BW were randomly assigned to one of five treatments: 1) basal diet of oaten:lucerne chaff (Basal); 2) Basal + fish meal (9% DM) = FM; 3) Basal + fish oil (1.5% DM) with protected sunflower meal (9% DM ) = FOSMP; 4) Basal + fish oil (1.5% DM) = FO; or 5) Basal + protected sunflower meal (10.5% DM) = SMP. Daily intake of ME (9.60 - 10.5 MJ ME/d) and CP (150 to 168 g/d) in all treatments was kept similar by varying the ratio of oaten:lucerne chaff and by feeding the animals at 90% ad libitum intake. Blood samples were collected at the start of the experiment and on the day (d 42) prior to slaughter. Lambs were then slaughtered at a commercial abattoir. At 24 h postmortem carcass traits were measured and longis-simus thoracis muscle taken for analysis of FA of phospholipid and triglyceride fractions. Lambs fed FO and FOSMP showed a marked increase in muscle longchain n-3 FA (P < 0.001) and a reduction in magnitude of the rise in insulin concentration (P < 0.001) after feeding compared with lambs fed Basal and SMP diets. Lambs in FM had a moderate increase (P < 0.001) in muscle long-chain n-3 FA content. Compared with Basal diet, both plasma total cholesterol (P < 0.02) and high-density lipoprotein cholesterol (P < 0.001) levels were greater in SMP and less in FO and FOSMP treat- ments. The i.m. fat content was reduced (P < 0.05) in FM and FO treatments, but carcass weight was increased only with fish meal (P < 0.03). Adding SMP to FO produced muscle with an intermediate level of i.m. fat, whereas muscle long-chain n-3 FA, i.m. fat, and insulin concentration were unchanged with SMP treatment. These results indicate that an increase in carcass weight in FM may be due to the supply of ruminally undegraded protein. They also suggest that fish oil along with fish meal can increase long-chain n-3 FA content in phospholipid of muscle membrane. This may be associated with reduced i.m. fat content and altered insulin action and lipoprotein metabolism.

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Automatic events classification is an essential requirement for constructing an effective sports video summary. It has become a well-known theory that the high-level semantics in sport video can be “computationally interpreted” based on the occurrences of specific audio and visual features which can be extracted automatically. State-of-the-art solutions for features-based event classification have only relied on either manual-knowledge based heuristics or machine learning. To bridge the gaps, we have successfully combined the two approaches by using learning-based heuristics. The heuristics are constructed automatically using decision tree while manual supervision is only required to check the features and highlight contained in each training segment. Thus, fully automated construction of classification system for sports video events has been achieved. A comprehensive experiment on 10 hours video dataset, with five full-match soccer and five full-match basketball videos, has demonstrated the effectiveness/robustness of our algorithms.

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