3,301 research outputs found
Variance in biomass-allocation fractions is explained by distribution in European trees
Intraspecific variability in ecological traits confers the ability of a species to adapt to an ever-changing environment. Fractions of biomass allocation in plants (BAFs) represent both ecological traits and direct expressions of investment strategies and so have important implications on plant fitness, particularly under current global change. - We combined data on BAFs of trees in > 10 000 forest plots with their distributions in Europe. We aimed to test whether plant species with wider distributions have more or less variable intraspecific variance of the BAFs foliage-woody biomass and shoot-root ratios than species with limited distribution. - Irrespective of corrections for tree age and phylogenetic relatedness, the standard deviation in BAFs was up to three times higher in species with the most extensive distributions than in those with the least extensive distribution due to a higher genetic diversity. Variance in BAFs also increased with latitude. - We show that a combination of 36% tree genetic diversity and 64% environmental variability explains variance in BAFs and implies that changes in genetic diversity occur quickly. Genetic diversity should thus play a key role in regulating species responses to future climate change. Loss of habitat, even if transient, could induce a loss of genetic diversity and hinder species survival
Comparison of moisture management methods for the bioremediation of hydrocarbon contaminated soil
Different moisture management methods were compared for biodegradation efficiency in sandy and organic soils. The conventional method consisted in maintaining the soil moisture at approximately 50to 75% field capacity accompanied by daily aeration and mixing. In the test method, the soil was allowed to dry out completely for three to four days after which the soil was moistened to 50 to 75% of field capacity and mixed daily for five days. In the test method the drying and moisturizing cycles were maintained throughout the experiment. There was no difference in treatments in the sandy soil, both treatments resulting in the detoxification to background levels within five weeks. During the processingof the organic soil, an increase in toxicity was observed, apparently due to increased availability of hydrocarbons, and possibly due to the production of toxic intermediates of biodegradation. The transformation rate in the test method was 22% less than in the conventional method, although thistransformation started at least four weeks earlier than in the conventional method. Based on these observations, a combination of drying (to increase bioavailability) and conventional moisture management (to stimulate hydrocarbon degrading microorganisms) is recommended.Key words: Remediation, toxicity, petroleum
The challenges of integrating biodiversity and ecosystem services monitoring and evaluation at a landscape-scale wetland restoration project in the UK
There is an increasing emphasis on the restoration of ecosystem services as well as of biodiversity, especially where restoration projects are planned at a landscape-scale. This increase in the diversity of restoration aims has a number of conceptual and practical implications for the way that restoration projects are monitored and evaluated. Landscape-scale projects require monitoring of not only ecosystem services and biodiversity but also of ecosystem processes since these can underpin both. Using the experiences gained at a landscape-scale wetland restoration project in the UK we discuss a number of issues that need to be considered, including the choice of metrics for monitoring ecosystem services and the difficulties of assessing the interactions between ecosystem processes, biodiversity and ecosystem services. Particular challenges that we identify, using two pilot data sets, include the de-coupling of monetary metrics used for monitoring ecosystem services from biophysical change on the ground and the wide range of factors external to a project that influence the monitoring results. We highlight the fact that the wide range of metrics necessary to evaluate the ecosystem service, ecosystem process and biodiversity outcomes of landscape-scale projects presents a number of practical challenges including: the need for high levels of varied expertise, high costs, incommensurate monitoring outputs and the need for careful management of monitoring results especially where they may be used in making decisions about the relative importance of project aims.This research is linked to grants EN 06-2151 and 09-2739 from the Esmée Fairbairn Foundation.This is the author accepted manuscript. The final version is available from Ecology and Society via https://doi.org//10.5751/ES-08616-21031
TEMPRANILLO is a regulator of juvenility in plants
Many plants are incapable of flowering in inductive daylengths during the early juvenile vegetative phase (JVP). Arabidopsis mutants with reduced expression of TEMPRANILLO (TEM), a repressor of FLOWERING LOCUS T (FT) had a shorter JVP than wild-type plants. Reciprocal changes in mRNA expression of TEM and FT were observed in both Arabidopsis and antirrhinum, which correlated with the length of the JVP. FT expression was induced just prior to the end of the JVP and levels of TEM1 mRNA declined rapidly at the time when FT mRNA levels were shown to increase. TEM orthologs were isolated from antirrhinum (AmTEM) and olive (OeTEM) and were expressed most highly during their juvenile phase. AmTEM functionally complemented AtTEM1 in the tem1 mutant and over-expression of AmTEM prolonged the JVP through repression of FT and CONSTANS (CO). We propose that TEM may have a general role in regulating JVP in herbaceous and woody species
Endothelial Jagged1 promotes solid tumor growth through both pro-angiogenic and angiocrine functions
Angiogenesis is an essential process required for tumor growth and progression. The Notch signaling pathway has been identified as a key regulator of the neo-angiogenic process. Jagged-1 (Jag1) is a Notch ligand required for embryonic and retinal vascular development, which direct contribution to the regulation of tumor angiogenesis remains to be fully characterized.
The current study addresses the role of endothelial Jagged1-mediated Notch signaling in the context of tumoral angiogenesis in two different mouse tumor models: subcutaneous Lewis Lung Carcinoma (LLC) tumor transplants and the autochthonous Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP).
The role of endothelial Jagged1 in tumor growth and neo-angiogenesis was investigated with endothelial-specific Jag1 gain- and loss-of-function mouse mutants (eJag1OE and eJag1cKO). By modulating levels of endothelial Jag1, we observed that this ligand regulates tumor vessel density, branching, and perivascular maturation, thus affecting tumor vascular perfusion. The pro-angiogenic function is exerted by its ability to positively regulate levels of Vegfr-2 while negatively regulating Vegfr-1. Additionally, endothelial Jagged1 appears to exert an angiocrine function possibly by activating Notch3/Hey1 in tumor cells, promoting proliferation, survival and epithelial-to-mesenchymal transition (EMT), potentiating tumor development. These findings provide valuable mechanistic insights into the role of endothelial Jagged1 in promoting solid tumor development and support the notion that it may constitute a promising target for cancer therapy
Occupational and Environmental Risks from Mancozeb in Aviation Facilities in the Banana Producing Area of Teapa, Tabasco, Mexico
Purpose: To identify occupational risks and practices in the four aerial fumigation facilities in the Sierra banana growing region and to evaluate environmental impacts from Mancozeb use.Methods: Occupational health risks were identified and practices in the four aerial fumigation facilities in the Sierra banana growing region were documented. Semi-structured interviews were conducted with installation managers. To evaluate environmental impact, samples of water and soil were collected and analysed in an acute toxicity bioassay with Vibrio fischeri, using uncontaminated soil and water to establish background levels.Results: Even in the largest and best-equipped facility, serious risks to workers’ health were encountered from inadequate use of protective equipment by workers. Furthermore, excessive use of pesticide, lack of re-use of unused product, poor facility design and poor use of wash-water were observed, resulting in maximum toxicity of > 5 times background in discharged water. Parallel soil samples were > 20 times more toxic than background, being most toxic at > 0.5 km from the discharge point.Conclusion: Areas of opportunity to improve worker health and the environment include proper and consistent use of protective equipment, re-use of unused product, wastewater reduction and appropriate wastewater treatment.Keywords: Black Sigatoka, Ethylene thiourea, Fumigation, Pesticide, Mancozeb, Airports, Microtox, Vibrio fischeri, Occupational health risks, Toxicit
A specious unlinking strategy
We show that the following unlinking strategy does not always yield an optimal sequence of crossing changes: first split the link with the minimal number of crossing changes, and then unknot the resulting components
Effect of a vitamin/mineral supplement on children and adults with autism
<p>Abstract</p> <p>Background</p> <p>Vitamin/mineral supplements are among the most commonly used treatments for autism, but the research on their use for treating autism has been limited.</p> <p>Method</p> <p>This study is a randomized, double-blind, placebo-controlled three month vitamin/mineral treatment study. The study involved 141 children and adults with autism, and pre and post symptoms of autism were assessed. None of the participants had taken a vitamin/mineral supplement in the two months prior to the start of the study. For a subset of the participants (53 children ages 5-16) pre and post measurements of nutritional and metabolic status were also conducted.</p> <p>Results</p> <p>The vitamin/mineral supplement was generally well-tolerated, and individually titrated to optimum benefit. Levels of many vitamins, minerals, and biomarkers improved/increased showing good compliance and absorption. Statistically significant improvements in metabolic status were many including: total sulfate (+17%, p = 0.001), S-adenosylmethionine (SAM; +6%, p = 0.003), reduced glutathione (+17%, p = 0.0008), ratio of oxidized glutathione to reduced glutathione (GSSG:GSH; -27%, p = 0.002), nitrotyrosine (-29%, p = 0.004), ATP (+25%, p = 0.000001), NADH (+28%, p = 0.0002), and NADPH (+30%, p = 0.001). Most of these metabolic biomarkers improved to normal or near-normal levels.</p> <p>The supplement group had significantly greater improvements than the placebo group on the Parental Global Impressions-Revised (PGI-R, Average Change, p = 0.008), and on the subscores for Hyperactivity (p = 0.003), Tantrumming (p = 0.009), Overall (p = 0.02), and Receptive Language (p = 0.03). For the other three assessment tools the difference between treatment group and placebo group was not statistically significant.</p> <p>Regression analysis revealed that the degree of improvement on the Average Change of the PGI-R was strongly associated with several biomarkers (adj. R<sup>2 </sup>= 0.61, p < 0.0005) with the initial levels of biotin and vitamin K being the most significant (p < 0.05); both biotin and vitamin K are made by beneficial intestinal flora.</p> <p>Conclusions</p> <p>Oral vitamin/mineral supplementation is beneficial in improving the nutritional and metabolic status of children with autism, including improvements in methylation, glutathione, oxidative stress, sulfation, ATP, NADH, and NADPH. The supplement group had significantly greater improvements than did the placebo group on the PGI-R Average Change. This suggests that a vitamin/mineral supplement is a reasonable adjunct therapy to consider for most children and adults with autism.</p> <p>Trial Registration</p> <p><b>Clinical Trial Registration Number: </b><a href="http://www.clinicaltrials.gov/ct2/show/NCT01225198">NCT01225198</a></p
Contribution of anadromous fish to the diet of European catfish in a large river system
Many anadromous fish species, when migrating from the sea to spawn in fresh waters, can potentially be a valuable prey for larger predatory fish, thereby efficiently linking these two ecosystems. Here, we assess the contribution of anadromous fish to the diet of European catfish (Silurus glanis) in a large river system (Garonne, southwestern France) using stable isotope analysis and allis shad (Alosa alosa) as an example of anadromous fish. Allis shad caught in the Garonne had a very distinct marine delta(13)C value, over 8 per thousand higher after lipid extraction compared to the mean delta(13)C value of all other potential freshwater prey fish. The delta(13)C values of European catfish varied considerably between these two extremes and some individuals were clearly specializing on freshwater prey, whereas others specialized on anadromous fish. The mean contribution of anadromous fish to the entire European catfish population was estimated to be between 53% and 65%, depending on the fractionation factor used for delta(13)C
Standardising outcomes for clinical trials and systematic reviews
Fifteen years ago, what was to become OMERACT met for the first time in The Netherlands to discuss ways in which the multitude of outcomes in assessments of the effects of treatments for rheumatoid arthritis might be standardised. In Trials, Tugwell et al have described the need for, and success of, this initiative [1] and Cooney and colleagues have set out their plans for a corresponding initiative for ulcerative colitis [2]. Why do we need such initiatives? What\u27s the problem? And are these and other initiatives the solution
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