Substrate quality and the temperature sensitivity of soil organic matter decomposition

Copyright © 2008 Elsevier. NOTICE: This is the author’s version of a work accepted for publication by Elsevier. Changes resulting from the publishing process, including peer review, editing, corrections, structural formatting and other quality control mechanisms, may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Soil Biology and Biochemistry, 2008, Vol. 40, Issue 7, pp. 1567 – 1574 http://dx.doi.org/10.1016/j.soilbio.2008.01.007Determining the relative temperature sensitivities of the decomposition of the different soil organic matter (SOM) pools is critical for predicting the long-term impacts of climate change on soil carbon (C) storage. Although kinetic theory suggests that the temperature sensitivity of SOM decomposition should increase with substrate recalcitrance, there remains little empirical evidence to support this hypothesis. In the study presented here, sub-samples from a single bulk soil sample were frozen and sequentially defrosted to produce samples of the same soil that had been incubated for different lengths of time, up to a maximum of 124 days. These samples were then placed into an incubation system which allowed CO2 production to be monitored constantly and the response of soil respiration to short-term temperature manipulations to be investigated. The temperature sensitivity of soil CO2 production increased significantly with incubation time suggesting that, as the most labile SOM pool was depleted the temperature sensitivity of SOM decomposition increased. This study is therefore one of the first to provide empirical support for kinetic theory. Further, using a modelling approach, we demonstrate that it is the temperature sensitivity of the decomposition of the more recalcitrant SOM pools that will determine long-term soil-C losses. Therefore, the magnitude of the positive feedback to global warming may have been underestimated in previous modelling studies

Management of water resources in South Africa: A review

In South Africa, there are many challenges regarding water management. Inadequate rainfall, may contribute to mismanagement, hence political breakdowns and racial groups do also contribute to the problem. To list some of the major challenges for effective management are: limited physical resources, a long cycle of inadequate rainfall, a rapid growing population, and stagnant economies. Water resource management is crucial for human security. In South Africa, almost everyone is affected by mismanagement of water resource, hence those living in poor area are the most affected as they do not have access to potable water and proper sanitation. Many policy-makers, researchers, and water managers advocate that water must be managed at the level of river basins, based on the argument that river basins are a ‘‘natural’’ unit and thus the logical unit for water management. Although stakeholder participation in water management is advocated, actually including the poor and achieving substantive stakeholder representation has proven elusive in practice. More often than not, participation is little more than token consultation, with no decision-making power in the hands of the people concerned? Too often, the participation discourse draws attention away from the very real social and economic differences between people and the need for the redistribution of resources, entitlements, and opportunities. This is typified by the definition of stakeholders as water.Keywords: Water, management, resources, stakeholder, population, economy

The African Lungfish (\u3cem\u3eProtopterus dolloi\u3c/em\u3e): Ionoregulation and Osmoregulation in a Fish out of Water

Although urea production and metabolism in lungish have been thoroughly studied, we have little knowledge of how internal osmotic and electrolyte balance are controlled during estivation or in water. We tested the hypothesis that, compared with the body surface of teleosts, the slender African lungfish (Protopterus dolloi) body surface was relatively impermeable to water, Na+ and Cl- due to its greatly reduced gills. Accordingly, we measured the tritiated water (3H-H2O) flux in P. dolloi in water and during air exposure. In water, 3H-H2O efflux was comparable with the lowest measurements reported in freshwater teleosts, with a rate constant (K) of 17.6% body water h-1. Unidirectional ion fluxes, measured using 22Na+ and 36Cl-, indicated that Na+ and Cl- influx was more than 90% lower than values reported in most freshwater teleosts. During air exposure, a cocoon formed within 1 wk that completely covered the dorsolateral body surface. However, there were no disturbances to blood osmotic or ion (Na+, Cl-) balance, despite seven- to eightfold increases in plasma urea after 20 wk. Up to 13-fold increases in muscle urea (on a dry-weight basis) were the likely explanation for the 56% increase in muscle water content observed after 20 wk of air exposure. The possibility that muscle acted as a “water reservoir” during air exposure was supported by the 20% decline in body mass observed during subsequent reimmersion in water. This decline in body mass was equivalent to 28 mL water in a 100-g animal and was very close to the calculated net water gain (approximately 32 mL) observed during the 20-wk period of air exposure. Tritiated water and unidirectional ion fluxes on air-exposed lungfish revealed that the majority of water and ion exchange was via the ventral body surface at rates that were initially similar to aquatic rates. The 3H-H2O flux declined over time but increased upon reimmersion. We conclude that the slender lungfish body surface, including the gills, has relatively low permeability to water and ions but that the ventral surface is an important site of osmoregulation and ionoregulation. We further propose that an amphibian-like combination of ventral skin water and ion permeability, plus internal urea accumulation during air exposure, allows P. dolloi to extract water from its surroundings and to store water in the muscle when the water supply becomes limited

Exploring the relationship between cyberbullying and unnatural child death: an ecological study of twenty-four European countries

Background Internet risk has been recognized as a child safety problem, but evidence is insufficient to conclude that a child's online risk exposure can lead to physical harm. This study aims to explore the ecological relationship between Internet risk exposure and unnatural child death. Methods Multiple secondary data sources were used: online exposure to content about self-harm, cyberbullying, and Internet addiction data (EU Kids Online survey, 2010); and mortality data (European Detailed Mortality Database, 2010 or the latest year if not available) of 24 European countries. Correlations were found using quasi-Poisson regression. Countries' prevalence rates of psychiatric problems (European Social Survey Round 3 and 6, 2006 and 2012) were used to test for possible spuriousness. Results This study finds that countries with higher rates of cyberbullying were more likely to have a higher incidence of unnatural child death. A 1 percent rise in the prevalence of cyberbullying translated into a 28% increase in risk of unnatural child death (95% CI: 2%-57%). No evidence was found to substantiate confounding effect of the national prevalence of depressive symptoms or traditional bullying. Conclusions Explanations are given for the findings. We conclude that intervention programs designed to serve as precautionary measures for risk minimisation should be considered.published_or_final_versio

Cocaine by-product detection with metal oxide semiconductor sensor arrays

A range of n-type and p-type metal oxide semiconductor gas sensors based on SnO2 and Cr2O3 materials have been modified with zeolites H-ZSM-5, Na-A and H–Y to create a gas sensor array able to successfully detect a cocaine by-product, methyl benzoate, which is commonly targeted by detection dogs. Exposure to vapours was carried out with eleven sensors. Upon data analysis, four of these that offered promising qualities for detection were subsequently selected to understand whether machine learning methods would enable successful and accurate classification of gases. The capability of discrimination of the four sensor array was assessed against nine different vapours of interest; methyl benzoate, ethane, ethanol, nitrogen dioxide, ammonia, acetone, propane, butane, and toluene. When using the polykernel function (C = 200) in the Weka software – and just five seconds into the gas injection – the model was 94.1% accurate in successfully classifying the data. Although further work is necessary to bring the sensors to a standard of detection that is competitive with that of dogs, these results are very encouraging because they show the potential of metal oxide semiconductor sensors to rapidly detect a cocaine by-product in an inexpensive way

Outcomes in Trials for Management of Caries Lesions (OuTMaC):protocol

Background Clinical trials on caries lesion management use an abundance of outcomes, hampering comparison or combination of different study results and their efficient translation into clinical practice. Core outcome sets are an agreed standardized collection of outcomes which should be measured and reported in all trials for a specific clinical area. We aim to develop a core outcome set for trials investigating management of caries lesions in primary or permanent teeth conducted in primary or secondary care encompassing all stages of disease. Methods To identify existing outcomes, trials on prevention and trials on management of caries lesions will be screened systematically in four databases. Screening, extraction and deduplication will be performed by two researchers until consensus is reached. The definition of the core outcome set will by based on an e-Delhi consensus process involving key stakeholders namely patients, dentists, clinical researchers, health economists, statisticians, policy-makers and industry representatives. For the first stage of the Delphi process, a patient panel and a separate panel consisting of researchers, clinicians, teachers, industry affiliated researchers, policy-makers, and other interested parties will be held. An inclusive approach will be taken to involve panelists from a wide variety of socio-economic and geographic backgrounds. Results from the first round will be summarized and fed back to individuals for the second round, where panels will be combined and allowed to modify their scoring in light of the full panel’s opinion. Necessity for a third round will be dependent on the outcome of the first two. Agreement will be measured via defined consensus rules; up to a maximum of seven outcomes. If resources allow, we will investigate features that influence decision making for different groups. Discussion By using an explicit, transparent and inclusive multi-step consensus process, the planned core outcome set should be justifiable, relevant and comprehensive. The dissemination and application of this core outcome set should improve clinical trials on managing caries lesions and allow comparison, synthesis and implementation of scientific data. Trial registration Registered 12 April 2015 at COMET (http://www.comet-initiative.org

Respiratory distress in a newborn

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Partial rhombencephalosynapsis and Chiari II malformation

We report a rare case of partial rhombencephalosynapsis coexistent with Chiari II malformation in a 6-year-old girl and discuss the features of these entities on magnetic resonance imaging.published_or_final_versio

ESEM-EDS investigation of the weathering of a heritage sydney sandstone

The degradation of Sydney sandstone used to build the heritage St Mary's Cathedral in Sydney, Australia, has been investigated using environmental scanning electron microscopy combined with energy dispersive X-ray spectroscopy. This technique provided the structural details of the cementing clay and an elemental characterization the sandstone. The observed differences in the elemental composition of the unweathered and weathered sandstones were associated with changes to the clay microstructure upon weathering. The results support the substitution theory that Fe3+ replaces Al3+ in the kaolinite clay component upon weathering. An examination of the impurities present prior to a nonstructural iron removal treatment revealed the presence of minerals that may provide a source of the elements responsible for the substitution process. © 2011 Microscopy Society Of America

Associating Child Sexual Abuse with Child Victimization in China

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