167 resultados para Nitrogen rates


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Accumulating research suggests that rates of child sexual abuse are comparatively low in China. This commentary is an effort to evaluate whether it reflects a true lower prevalence or alternatively the effect of inhibited disclosure by victims. We conclude that while some estimates have almost certainly been affected by inhibited disclosure, the overall magnitude of the contrast between Chinese and international rates, particularly for girls, and its consistency with other indicators do suggest a true lower prevalence, although the evidence is equivocal. We discuss some factors that could account for such lower rates including Confucian family values, definitions of masculinity and a collectivist culture that may be protective.

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A common measure of the economic performance of different fleet segments in fisheries is the rate of return on capital. However, in the English Channel (UK), observed changes in the fleet structure are at odds with expectations given the observed rates of return on capital. This disjunction between expected and observed behaviour raises the question as to the appropriateness of rate of return on capital as a measure of economic performance for small boats whose main input is often non-wage labour. In this paper, an alternative performance indicator is developed based on returns on owner-operator labour. This indicator appears to be of more relevance to small scale boats than the traditional returns on capital, and a better indicator of the direction of adjustment in the fishery.

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This report describes results and conclusions from the monitoring component of the Douglas Shire Council (DSC) water quality project. The components of this project that this report addresses are: • Site selection and installation of in-stream and off-paddock automatic water quality monitoring equipment in the Douglas Shire. • Design of appropriate sampling strategies for automatic stations. • Estimation of loads of suspended sediment, total nitrogen and total phosphorus in rivers and also estimation of the changes in nutrient loads from sugar cane under different fertilizer application rates. • Development of a community-based water quality sampling program to complement the automatic sampling efforts. • Design of an optimised, long-term water quality monitoring strategy.

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Clear-fell harvest of forest concerns many wildlife biologists because of loss of vital resources such as roosts or nests, and effects on population viability. However, actual impact has not been quantified. Using New Zealand long-tailed bats (Chalinolobus tuberculatus) as a model species we investigated impacts of clear-fell logging on bats in plantation forest. C. tuberculatus roost within the oldest stands in plantation forest so it was likely roost availability would decrease as harvest operations occurred. We predicted that post-harvest: (1) roosting range sizes would be smaller, (2) fewer roosts would be used, and (3) colony size would be smaller. We captured and radiotracked C. tuberculatus to day-roosts in Kinleith Forest, an exotic plantation forest, over three southern hemisphere summers (Season 1 October 2006–March 2007; Season 2 November 2007–March 2008; and Season 3 November 2008–March 2009). Individual roosting ranges (100% MCPs) post harvest were smaller than those in areas that had not been harvested, and declined in area during the 3 years. Following harvest, bats used fewer roosts than those in areas that had not been harvested. Over 3 years 20.7% of known roosts were lost: 14.5% due to forestry operations and 6.2% due to natural tree fall. Median colony size was 4.0 bats (IQR = 2.0–8.0) and declined during the study, probably because of locally high levels of roost loss. Post harvest colonies were smaller than colonies in areas that had not been harvested. Together, these results suggest the impact of clear-fell harvest on long-tailed bat populations is negative.

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The hypothesis that twinning raises risk for behavioral difficulties in childhood is persistent, yet there is limited and inconsistent empirical evidence. Simple mean comparison without control for confounders provides data on prevalence rates but cannot provide knowledge about risk or etiology. To assess the effect of twin relationship on behavior, comparison of patterns of association with single-born siblings may be informative. Analyses of data from an Australian sample of twins and single-born children (N = 305, mean age 4 years 9 months, and a follow-up 12 months later) were undertaken. The outcome measure was the Strengths and Difficulties Questionnaire. Predictor and control measures were obtained from parent report on the sibling/co-twin relationship behavior, family demographics, and obstetric history. We assessed difference between twins and single-born children in two respects: (a) mean behavioral difficulties, and (b) patterns of association between sibling relationship and behavioral difficulties, controlling for confounders. Results showed no differences in mean levels of behavioral difficulties between twins and single-born siblings identifying the importance of statistical control for family and obstetric adversity. Differences in patterns of association were found; for twin children, conflict in their co-twin relationship predicted externalizing behaviors, while for single-born children conflict predicted internalizing behaviors. The findings of mean differences between twin and single-born children in social background, but not in behavioral difficulties, underscore the necessity of statistical control to identify risk associated with twinning compared with risk associated with family and obstetric background factors.

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Primary objective: To investigate whether assessment method influences the type of post-concussion-like symptoms. Methods and procedures: Participants were 73 Australian undergraduate students (Mage = 24.14, SD = 8.84; 75.3% female) with no history of mild traumatic brain injury (mTBI). Participants reported symptoms experienced over the previous 2 weeks in response to an open-ended question (free report), mock interview and standardized checklist (British Columbia Post-concussion Symptom Inventory; BC-PSI). Main outcomes and results: In the free report and checklist conditions, cognitive symptoms were reported significantly less frequently than affective (free report: p < 0.001; checklist: p < 0.001) or somatic symptoms (free report: p < 0.001; checklist: p = 0.004). However, in the mock structured interview condition, cognitive and somatic symptoms were reported significantly less frequently than affective symptoms (both p < 0.001). No participants reported at least one symptom from all three domains when assessed by free report, whereas most participants did so when symptoms were assessed by a mock structured interview (75%) or checklist (90%). Conclusions: Previous studies have shown that the method used to assess symptoms affects the number reported. This study shows that the assessment method also affects the type of reported symptoms.

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Is there a threshold above which hand-rub solution consumption is efficient for decreasing MRSA incidence? [J Hosp Infect. 2009] Association between an index of consumption of hand-rub solution and the incidence of acquired meticillin-resistant Staphylococcus aureus in an intensive care unit.

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An effective means of facilitating DNA vaccine delivery to antigen presenting cells is through biodegradable microspheres. Microspheres offer distinct advantages over other delivery technologies by providing release of DNA vaccine in its bioactive form in a controlled fashion. In this study, biodegradable poly(D,L-lactide-coglycolide) (PLGA) microspheres containing polyethylenimine (PEI) condensed plasmid DNA (pDNA) were prepared using a 40 kHz ultrasonic atomization system. Process synthesis parameters, which are important to the scale-up of microspheres that are suitable for nasal delivery (i.e., less than 20 μm), were studied. These parameters include polymer concentration; feed flowrate; volumetric ratio of polymer and pDNA-PEI (plasmid DNA-polyethylenimine) complexes; and nitrogen to phosphorous (N/P) ratio. PDNA encapsulation efficiencies were predominantly in the range 82-96%, and the mean sizes of the particle were between 6 and 15 μm. The ultrasonic synthesis method was shown to have excellent reproducibility. PEI affected morphology of the microspheres, as it induced the formation of porous particles that accelerate the release rate of pDNA. The PLGA microspheres displayed an in vitro release of pDNA of 95-99% within 30 days and demonstrated zero order release kinetics without an initial spike of pDNA. Agarose electrophoresis confirmed conservation of the supercoiled form of pDNA throughout the synthesis and in vitro release stages. It was concluded that ultrasonic atomization is an efficient technique to overcome the key obstacles in scaling-up the manufacture of encapsulated vaccine for clinical trials and ultimately, commercial applications.

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This article examines the trends of road traffic crash (RTC) fatality rates in OECD countries over the past four decades. Based on recent developments in the economic growth literature we propose and test the hypothesis that RTC fatality rates initially increase with economic development, peak, and then gradually decrease. The theory predicts that, as a result, the RTC fatality rates of different countries will tend to converge over time. Our results for the period 1961–2007 reveal no evidence of the convergence of RTC fatality rates across the OECD as a whole for that time period. Nevertheless, there is evidence of convergence among sub-groups of countries. This evidence may assist policymakers as an additional way of benchmarking their country's performance against that of its peers and to identify the next-closest peer in country sub-groups with superior road safety performance.

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This research study comprehensively analyses the dynamics of nitrogen and suspended solids removal in stormwater biofilters. The study focuses on pollutant removal during an event with time, rather than the conventional event-mean analysis. Antecedent dry days (number of days in between rainfall) during which biofilters remain dry and the inflow concentration of pollutants were two other important variables analysed in this study. The research outcome highlights the significance of dry-phase processes and the process of stabilization on filter performance and sets a paradigm shift from the current approach towards an innovative way of performance analysis of biofilters.

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A nitrogen modified graphdiyne is investigated concerning its performance for hydrogen purification from CH4 and CO by density functional theory with dispersion correction and transition state theory. After nitrogen doping, the porous N-graphdiyne nano-mesh shows a reduced H2 diffusion barrier and increased CH4/CO diffusion barriers, hence leading to an enhanced hydrogen purification capability.