904 resultados para primary sources
Resumo:
Nutrition plays an important role in the development of all organisms and in particular that of farmed aquatic species where costs associated with feed can often exceed 60% of total production costs. Crustacean species in addition, have the added metabolic requirement for regular moulting to allow normal growth and this requires large amounts of energy in the form of sugars (glucose). The current study explored the capacity of the giant freshwater prawn to produce endogenous cellulose-degrading enzymes capable of extracting nutrients (simple sugars) from plant sources in formulated feeds used in the prawn aquaculture industry. We identified a putative cellulase cDNA fragment in the target organism of 1576 base pairs in length of non-microbial origin that after protein modelling exhibited a TM-score of 0.916 with a described cellulase reported from another crustacean species. The functional role of cellulase enzymes is to hydrolyse cellulose to glucose and the fragment identified in GFP was highly expressed in the hepatopancreas, the site of primary food digestion and absorption in crustaceans. Hepatopancreatic tissue from Macrobrachium rosenbergii also showed active digestion of cellulose to glucose following an endoglucanase assay. Cellulase gene(s) are present in the genomes of many invertebrate taxa and play an active role in the conversion of cellulose to available energy. Identification and characterization of endogenous cellulase gene(s) in giant freshwater prawn can assist development of the culture industry because the findings confirm that potentially greater levels of low-cost plant-material could be included in artificial formulated diets in the future without necessarily compromising individual growth performance. Ultimately, this development may contribute to more efficient, cost-effective production systems for freshwater prawn culture stocks that meet the animal's basic nutritional requirements and that also support good individual growth rates.
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Humans dominate many important Earth system processes including the nitrogen (N) cycle. Atmospheric N deposition affects fundamental processes such as carbon cycling, climate regulation, and biodiversity, and could result in changes to fundamental Earth system processes such as primary production. Both modelling and experimentation have suggested a role for anthropogenically altered N deposition in increasing productivity, nevertheless, current understanding of the relative strength of N deposition with respect to other controls on production such as edaphic conditions and climate is limited. Here we use an international multiscale data set to show that atmospheric N deposition is positively correlated to aboveground net primary production (ANPP) observed at the 1-m2 level across a wide range of herbaceous ecosystems. N deposition was a better predictor than climatic drivers and local soil conditions, explaining 16% of observed variation in ANPP globally with an increase of 1 kg N·ha-1·yr-1 increasing ANPP by 3%. Soil pH explained 8% of observed variation in ANPP while climatic drivers showed no significant relationship. Our results illustrate that the incorporation of global N deposition patterns in Earth system models are likely to substantially improve estimates of primary production in herbaceous systems. In herbaceous systems across the world, humans appear to be partially driving local ANPP through impacts on the N cycle.
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After reading this chapter, you should be able to: • Identify the needs of early adolescents • Consider four key areas for supporting transitioning students (i.e., self, social, academic, and differentiation) • Identify resources that can help create successful transitioning programs • Understand ways to devise and facilitate transitioning programs
Resumo:
BACKGROUND After general surgery, the lower limb experiences some of the highest complication rates. However, little is known about contributing factors to surgical site failure in the lower limb dermatological surgery population. OBJECTIVE To determine the incidence of lower limb surgical site failure and to explore the predictors that contribute to surgical site failure. METHODS A prospective observational study design was used to collect data from 73 participants, from July 2010, to March 2012. Incidence was determined as a percentage of surgical site failure from the total population. Predictors were determined by the use of a binary logistic regression model. RESULTS The surgical site failure rate was 53.4%. Split-skin grafting had a higher failure rate than primary closures, 66% versus 26.1%. Predictors of lower limb surgical site failure were identified as increasing age (p = .04) and the presence of postoperative hematoma (p = .01), with all patients who developed surgical site infection experiencing surgical site failure (p = .01). CONCLUSION Findings from this study confirmed that the lower limb is at high risk of surgical site failure. Two predictors of surgical site failure from this cohort were determined. However, to understand this phenomenon and make recommendations to assist and reduce surgical site complications, further research in this field is required.
Resumo:
Problems can occur in mentoring relationships if there is a “lack of mentoring skills on the part of the mentor” (Soutter, Kerr - Roubicek & Smith, 2000, p. 6), which includes the effectiveness of mentor’s personal attributes. There is little Australian research that analyses primary teachers’ personal attributes for mentoring; hence this study aims to examine preservice teachers’ perceptions of their mentors’ personal attributes. Specifically, this study focuses on mentors’ personal attributes in relation to their mentoring of primary science teaching....
Resumo:
Introduction There are concerns about the science performance of Australian primary school students (Good rum, Hackling & Rennie, 2001), which requires a “major set of initiatives that focus on teacher beliefs and practices in the teaching and learning of science” (Sharpley, Tytler & Conley, 2000, p. 1). The science education community is calling for a “new approach” to science education in American schools, with an approach where a “mentor models, then coaches, then scaffolds, and then gradually fades scaffolding” (Barab & Hay, 2001, pp. 74, 90). The mentor, as modeller of practice, appears to be a key factor for enhancing science teaching, which may assist towards implementing science education reform
Resumo:
Perceptions of mentors' practices related to primary science teaching were obtained from final year preservice teachers after a 4-week practicum. Responses to a survey (n=59), constructed through literature-based practices and attributes of effective mentors, identified perceived strengths and weaknesses in the area of mentoring preservice teachers of primary science. Through exploratory factor analysis, this pilot study also tested the unidimensionality of mentoring practices and attributes assigned to categories (factors) that may characterise mentoring in primary science teaching. These suggested factors, namely, personal attributes, system requirements, pedagogical knowledge, modelling, and feedback had Cronbach alpha coefficients of internal consistency reliability of 0.93, 0.78, 0.94, 0.90, and 0.81 respectively. Survey responses indicated that mentors generally do not provide specific mentoring in primary science teaching. It is argued that science education reform requires the identification of factors and associated attributes and practices of mentoring primary science in order to effectively develop preservice teachers in primary science teaching.
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This thesis improves our insight towards the effects of using biodiesels on the particulate matter emission of diesel engines and contributes to our understanding of their potential adverse health effects. The novelty of this project is the use of biodiesel fuel with controlled chemical composition that enables us to relate changes of physiochemical properties of particles to specific properties of the biodiesel. For the first time, the possibility of a correlation of the volatility and the Reactive Oxygen Species concentration of the particles is investigated versus the saturation, oxygen content and carbon chain length of the fuel.
Resumo:
Twenty-nine first-year pre-service teachers' perceptions of mentoring and primary science teaching were collected through a literature-based survey. Frequencies, means, and standard deviations of these responses provided data for analysis on these mentoring practices. Results indicated that even though mentors may provide feedback, the majority of mentors do not provide specific primary science mentoring in the areas of pedagogical knowledge, system requirements, and the modeling of teaching practice. It appears that the mentor's personal attributes may also influence the quality of mentoring. There were tentative conclusions that first-year pre-service teachers may not have strong beliefs about specific primary science mentoring practices, and possibly because of inexperience, may not be critical enough to analyse their mentoring in primary science teaching. Identifying specific mentoring for developing primary science teaching may assist mentors in their practices with pre-service teachers.
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PBDE concentrations are higher in children compared to adults with exposure suggested to include dust ingestion. Besides the home environment, children spend a great deal of time in school classrooms which may be a source of exposure. As part of the “Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH)” project, dust samples (n=28) were obtained in 2011/12 from 10 Brisbane, Australia metropolitan schools and analysed using GC and LC–MS for polybrominated diphenyl ethers (PBDEs) -17, -28, -47, -49, -66, -85, -99, -100, -154, -183, and -209. Σ11PBDEs ranged from 11–2163 ng/g dust; with a mean and median of 600 and 469 ng/g dust, respectively. BDE-209 (range n.d. −2034 ng/g dust; mean (median) 402 (217) ng/g dust) was the dominant congener in most classrooms. Frequencies of detection were 96%, 96%, 39% and 93% for BDE-47, -99, -100 and -209, respectively. No seasonal variations were apparent and from each of the two schools where XRF measurements were carried out, only two classroom items had detectable bromine. PBDE intake for 8–11 year olds can be estimated at 0.094 ng/day BDE-47; 0.187 ng/day BDE-99 and 0.522 ng/day BDE-209 as a result of ingestion of classroom dust, based on mean PBDE concentrations. The 97.5% percentile intake is estimated to be 0.62, 1.03 and 2.14 ng/day for BDEs-47, -99 and -209, respectively. These PBDE concentrations in dust from classrooms, which are higher than in Australian homes, may explain some of the higher body burden of PBDEs in children compared to adults when taking into consideration age-dependant behaviours which increase dust ingestion.
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Mathematics has been perceived as the core area of learning in most educational systems around the world including Sri Lanka. Unfortunately, it is clearly visible that a majority of Sri Lankan students are failing in their basic mathematics when the recent grade five scholarship examination and ordinary level exam marks are analysed. According to Department of Examinations Sri Lanka , on average, over 88 percent of the students are failing in the grade 5 scholarship examinations where mathematics plays a huge role while about 50 percent of the students fail in there ordinary level mathematics examination. Poor or lack of basic mathematics skills has been identified as the root cause.
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Traffic law enforcement sanctions can impact on road user behaviour through general and specific deterrence mechanisms. The manner in which specific deterrence can influence recidivist behaviour can be conceptualised in different ways. While any reduction in speeding will have road safety benefits, the ways in which a ‘reduction’ is determined deserves greater methodological attention and has implications for countermeasure evaluation more generally. The primary aim of this research was to assess the specific deterrent impact of penalty increases for speeding offences in Queensland, Australia, in 2003 on two cohorts of drivers detected for speeding prior to and after the penalty changes were investigated. Since the literature is relatively silent on how to assess recidivism in the speeding context, the secondary research aim was to contribute to the literature regarding ways to conceptualise and measure specific deterrence in the speeding context. We propose a novel way of operationalising four measures which reflect different ways in which a specific deterrence effect could be conceptualised: (1) the proportion of offenders who re-offended in the follow up period; (2) the overall frequency of re-offending in the follow up period; (3) the length of delay to re-offence among those who re-offended; and (4) the average number of re-offences during the follow up period among those who re-offended. Consistent with expectations, results suggested an absolute deterrent effect of penalty changes, as evidenced by significant reductions in the proportion of drivers who re-offended and the overall frequency of re-offending, although effect sizes were small. Contrary to expectations, however, there was no evidence of a marginal specific deterrent effect among those who re-offended, with a significant reduction in the length of time to re-offence and no significant change in the average number of offences committed. Additional exploratory analyses investigating potential influences of the severity of the index offence, offence history, and method of detection revealed mixed results. Access to additional data from various sources suggested that the main findings were not influenced by changes in speed enforcement activity, public awareness of penalty changes, or driving exposure during the study period. Study limitations and recommendations for future research are discussed with a view to promoting more extensive evaluations of penalty changes and better understanding of how such changes may impact on motorists’ perceptions of enforcement and sanctions, as well as on recidivist behaviour.
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Previous research with emergency service workers has examined the relationship between operational and organisational stress and negative indicators of mental health, and generally found that organisational stress is more strongly related to pathology than operational stress. The current study aimed to create and test a model predicting both posttraumatic stress disorder (PTSD) symptoms and posttraumatic growth (PTG) simultaneously in a sample of fire-fighters (N = 250). The results found that the model demonstrated good fit for the data. In contrast to previous research operational stress was directly related to PTSD symptoms, while organisational stress was not. Organisational stress was indirectly related to PTG, through the mediating role of organisational belongingness. This research identified organisational belongingness as a good target for psychosocial interventions aimed at promoting positive adaptation following the experience of trauma in emergency services.