534 research outputs found
Compost Application Affects Metal Uptake in Plants Grown in Urban Garden Soils and Potential Human Health Risk
Purpose This study explores the effect of varying organic matter content on the potential human health risk of consuming vegetables grown in urban garden soils.
Materials and methods Metal accumulation among edible tissues of green bean (Phaseolus vulgaris L.), lettuce (Lactuca sativa L.) and carrot (Daucus carota L.) was determined for plants grown in five urban garden soils amended with 0, 9, or 25% (v/v) compost. Potential risk to human health was assessed by calculating a bioconcentration factor and a hazard quotient.
Results and discussion Overall, the consumption of lettuce and green bean pods grown in some urban gardens posed a potential human health risk due to unacceptably high concentrations of cadmium or lead. In many cases, compost amendment increased the accumulation of metals in the vegetables. Even in soils considered uncontaminated by current guidelines, some hazard quotients exceeded the threshold value of 1. The compost used in this study had a high fulvic acid to humic acid ratio, which may explain increased concentrations of metals in plants grown in compost-amended soils.
Conclusions These results indicate a need to include soil characteristics, specifically organic matter quality, when setting threshold criteria for metal content of urban garden soils
Accumulation of Cadmium in Near-Isogenic Lines of Durum Wheat (Triticum Turgidum L. Var Durum): the Role of Transpiration
Concentrations of cadmium in the grain of durum wheat (Triticum turgidum L. var durum) are often above the internationally acceptable limit of 0.2 mg kg−1. Cultivars that vary in concentrations of cadmium in the grain have been identified but the physiology behind differential accumulation has not been determined. Three pairs of near-isogenic lines (isolines) of durum wheat that vary in aboveground cadmium accumulation (8982-TL ‘high’ and ‘low’, W9260-BC ‘high’ and ‘low’, and W9261-BG ‘high’ and ‘low’) were used to test the hypothesis that the greater amounts of cadmium in shoots of the ‘high’ isolines are correlated with greater volumes of water transpired. In general, cadmium content was positively correlated with transpiration only in the ‘low’ isolines. Although shoots of the ‘high’ isolines of W9260-BC and W9261-BG contained higher concentrations of cadmium than did their corresponding ‘low’ isolines, they did not transpire larger volumes of water. In addition, isolines of 8982-TL transpired less water than did the other pairs of isolines yet both ‘high’ and ‘low’ isolines of 8982-TL contained higher amounts of cadmium than did the other pairs. The difference between ‘high’ and ‘low’ isolines appears to be related to the relative contribution of transpiration to cadmium translocation to the shoot. Increased transpiration was associated with increased cadmium content in the ‘low’ isolines but in the ‘high’ isolines increased cadmium in the shoot occurred independently of the volume of water transpired
Production of Organic Acids and Adsorption of Cd on Roots of Durum Wheat (Triticum turgidum L. var. durum)
A number of isolines of durum wheat (Triticum turgidum var durum) differ in their translocation of Cd. In the field, the high isolines accumulate twice the Cd in leaves and grain when compared to the low isolines. The hypothesis that differential accumulation of Cd is associated with differential production of organic acids was tested by measuring Cd content in tissues, Cd partitioning within the root, and organic acids in tissues. In solution culture, the high and low isolines of W9261-BG did not differ in any of the variables measured. Within W9260-BC, the low isoline had half the Cd in its shoot, 30% more tightly-bound Cd in the root and higher concentrations of fumaric, malic, and succinic acids in the root compared to the high isoline. Differential Cd accumulation may be linked to differential adsorption and retention of Cd in the roots of the low Cd-accumulating isolines, possibly via chelation with organic acids
A microfluidic chip based model for the study of full thickness human intestinal tissue using dual flow
© 2016 Author(s). The study of inflammatory bowel disease, including Ulcerative Colitis and Crohn's Disease, has relied largely upon the use of animal or cell culture models; neither of which can represent all aspects of the human pathophysiology. Presented herein is a dual flow microfluidic device which holds full thickness human intestinal tissue in a known orientation. The luminal and serosal sides are independently perfused ex vivo with nutrients with simultaneous waste removal for up to 72 h. The microfluidic device maintains the viability and integrity of the tissue as demonstrated through Haematoxylin & Eosin staining, immunohistochemistry and release of lactate dehydrogenase. In addition, the inflammatory state remains in the tissue after perfusion on the device as determined by measuring calprotectin levels. It is anticipated that this human model will be extremely useful for studying the biology and tes ting novel interventions in diseased tissue
A prospective, multicentre, observational cohort study of analgesia and outcome after pneumonectomy
Background Meta-analysis and systematic reviews of epidural compared with paravertebral blockade analgesia techniques for thoracotomy conclude that although the analgesia is comparable, paravertebral blockade has a better short-term side-effect profile. However, reduction in major complications including mortality has not been proven.
Methods The UK pneumonectomy study was a prospective observational cohort study in which all UK thoracic surgical centres were invited to participate. Data presented here relate to the mode of analgesia and outcome. Data were analysed for 312 patients having pneumonectomy at 24 UK thoracic surgical centres in 2005. The primary endpoint was a major complication.
Results The most common type of analgesia used was epidural (61.1%) followed by paravertebral infusion (31%). Epidural catheter use was associated with major complications (odds ratio 2.2, 95% confidence interval 1.1–3.8; P=0.02) by stepwise logistic regression analysis.
Conclusions An increased incidence of clinically important major post-pneumonectomy complications was associated with thoracic epidural compared with paravertebral blockade analgesia. However, this study is unable to provide robust evidence to change clinical practice for a better clinical outcome. A large multicentre randomized controlled trial is now needed to compare the efficacy, complications, and cost-effectiveness of epidural and paravertebral blockade analgesia after major lung resection with the primary outcome of clinically important major morbidity
Adam Smith and Colonialism
In the context of debates about liberalism and colonialism, the arguments of Adam Smith have been taken as illustrative of an important line of anti-colonial liberal thought. The reading of Smith presented here challenges this interpretation. It argues that Smith’s opposition to colonial rule derived largely from its impact on the metropole, rather than on its impact on the conquered and colonised; that Smith recognised colonialism had brought ‘improvement’ in conquered territories and that Smith struggled to balance recognition of moral diversity with a universal moral framework and a commitment to a particular interpretation of progress through history. These arguments have a wider significance as they point towards some of the issues at stake in liberal anti-colonial arguments more generally
Recommended from our members
Sorcery and nature conservation
Representations of animals are diverse and can portray local understandings of nature conservation, information that is often missing from conservation debates. In Cantanhez National Park (southern Guinea-Bissau), chimpanzees (Pan troglodytes verus) are recognized as animals that share certain features with humans but live independently of them in the forest. However, chimpanzees are also integral to socially mediated, deep-rooted local narratives about sorcery and nature conservation. We use results from ethnographic research to explore local interpretations of chimpanzee attacks on people. Attacks by ‘bush’ chimpanzees occur when an animal is provoked by someone's actions towards it. Unprovoked attacks, however, are either interpreted as the act of a shape-shifted chimpanzee (i.e. a sorcerer) or as the responsibility of conservation stakeholders. In the case of unprovoked attacks, chimpanzee aggression is linked to a perceived abuse of power and to greed, with implications for nature conservation locally. Close analysis of local representations of animals contributes to a broader consideration of conservation priorities and practice
Was Adam Smith an individualist?
Smith is generally regarded as an individualist without qualification. This article argues that his predominantly individualist policy prescription is rooted in a more complex philosophy. He sees nature, including human nature, as a vast machine supervised by God and designed to maximize human happiness. Human weaknesses, as well as strengths, display the wisdom of God and play their part in this scheme. While Smith pays lip-service to justice, it is really social order that preoccupies him, and, within that, the defence of property. Individuals are valued as bearers of property. As persons, individuals are deceived by nature into acting in a socially beneficial way. In different ways Smith systematically denies the autonomy of the individual with respect to the whole of which he or she is part. For Smith, individual liberty is not the end, but the means, of sustaining social order and property
Habitat determinants of golden‐headed lion tamarin (Leontopithecus chrysomelas) occupancy of cacao agroforests: Gloomy conservation prospects for management intensification
Organismal distributions in human‐modified landscapes largely depend on the capacity of any given species to adapt to changes in habitat structure and quality. The golden‐headed lion tamarin (GHLT; Leontopithecus chrysomelas) is an Endangered primate from the Brazilian Atlantic Forest whose remaining populations occupy heterogeneous landscapes consisting primarily of shade cacao (Theobroma cacao) agroforestry, locally known as cabrucas. This cash crop can coexist with high densities of native tree species and holds a significant proportion of the native fauna, but its widely extolled wildlife‐friendly status is increasingly threatened by management intensification. Although this potentially threatens to reduce the distribution of GHLTs, the main determinants of tamarin's occupancy of cabrucas remain unknown, thereby limiting our ability to design and implement appropriate conservation practices. We surveyed 16 cabruca patches in southern Bahia, Brazil, and used occupancy modeling to identify the best predictors of GHLT patch occupancy. Key explanatory variables included vegetation structure, critical resources, landscape context, human disturbance, and predation pressure. We found a negative relationship between GHLT occupancy and the prevalence of jackfruit trees (Artocarpus heterophylus), which is likely associated with the low representation of other key food species for GHLTs. Conversely, cabrucas retaining large‐diameter canopy trees have a higher probability of GHLT occupancy, likely because these trees provide preferred sleeping sites. Thus, key large tree resources (food and shelter) are currently the main drivers of GHLT occupancy within cabruca agroecosystems. Since both factors can be directly affected by crop management practices, intensification of cabrucas may induce significant habitat impacts on GHLT populations over much of their remaining range‐wide distribution
- …