13 research outputs found
Contrasting effects of insect exclusion on wood loss in a temperate forest
Experimental efforts to determine how insects influence terrestrial wood decomposition are few, especially in temperate regions. To address this need, a five-year exclusion study was conducted in northern Mississippi, U.S.A., to quantify insect contributions to wood decay using one-meter loblolly pine (Pinus taeda L.) bolts. The study included three treatments: (1) ‘‘partially protected’’ bolts that were placed on cypermethrin-treated soil to exclude subterranean termites (Isoptera: Rhinotermitidae: Reticulitermes spp.) while permitting colonization by beetles (Coleoptera) and other saproxylic taxa, (2) ‘‘fully protected’’ bolts that were placed on cypermethrin-treated soil and enclosed within screen cages to protect against all insects and (3) ‘‘unprotected’’ bolts that were not subjected to either exclusion treatment. The full insect community consumed approximately 15–20% of wood volume in unprotected bolts, about six times more than in partially protected bolts from which termites were excluded. There were no differences in specific gravity (based on initial wood volume) or mass loss among treatments, however. It is not clear whether these findings are due to an inhibition of microbial decomposers by insects (e.g., antimicrobial compounds secreted by termites or ants), a stimulatory effect of the exclusion treatments (e.g., cypermethrin stimulating fungal growth or cages favorably altering wood moisture), or some combination of both. When based on final water-displaced volume, specific gravity was significantly higher for unprotected bolts than for those fully protected, probably because termites selectively consume the least dense wood. By the end of the study, about 20% of the final dry weight of unprotected bolts consisted of termite-imported soil. Wood volume consumed and soil content decreased with distance from the ends of the bolts whereas water content exhibited the opposite pattern. We detected a significant negative relationship between water content and volume consumed by termites, possibly because water content decreases with increasing wood density and termites tend to avoid high density wood. While insects clearly consume large volumes of wood in southeastern U.S. forests, our results suggest they do not act to accelerate mass loss beyond what is achieved by microbial decomposers. More research is needed to confirm this, however—especially given the uncertainties inherent to exclusion studies
Contrasting effects of insect exclusion on wood loss in a temperate forest
Experimental efforts to determine how insects influence terrestrial wood decomposition are few, especially in temperate regions. To address this need, a five-year exclusion study was conducted in northern Mississippi, U.S.A., to quantify insect contributions to wood decay using one-meter loblolly pine (Pinus taeda L.) bolts. The study included three treatments: (1) ‘‘partially protected’’ bolts that were placed on cypermethrin-treated soil to exclude subterranean termites (Isoptera: Rhinotermitidae: Reticulitermes spp.) while permitting colonization by beetles (Coleoptera) and other saproxylic taxa, (2) ‘‘fully protected’’ bolts that were placed on cypermethrin-treated soil and enclosed within screen cages to protect against all insects and (3) ‘‘unprotected’’ bolts that were not subjected to either exclusion treatment. The full insect community consumed approximately 15–20% of wood volume in unprotected bolts, about six times more than in partially protected bolts from which termites were excluded. There were no differences in specific gravity (based on initial wood volume) or mass loss among treatments, however. It is not clear whether these findings are due to an inhibition of microbial decomposers by insects (e.g., antimicrobial compounds secreted by termites or ants), a stimulatory effect of the exclusion treatments (e.g., cypermethrin stimulating fungal growth or cages favorably altering wood moisture), or some combination of both. When based on final water-displaced volume, specific gravity was significantly higher for unprotected bolts than for those fully protected, probably because termites selectively consume the least dense wood. By the end of the study, about 20% of the final dry weight of unprotected bolts consisted of termite-imported soil. Wood volume consumed and soil content decreased with distance from the ends of the bolts whereas water content exhibited the opposite pattern. We detected a significant negative relationship between water content and volume consumed by termites, possibly because water content decreases with increasing wood density and termites tend to avoid high density wood. While insects clearly consume large volumes of wood in southeastern U.S. forests, our results suggest they do not act to accelerate mass loss beyond what is achieved by microbial decomposers. More research is needed to confirm this, however—especially given the uncertainties inherent to exclusion studies
Reducing Pesticide Drift by Considering Propeller Rotation Effects From Aerial Application Near Buffer Zones
Off-target drift of chemical from agricultural spraying can damage sensitive crops, destroy beneficial insects, and intrude on human and domestic animal habitats, threatening environmental quality. Reduction of drift from aerial application can be facilitated at the edge of a field by offsetting spray ½ or 1 boom width from the field edge or by switching off one boom. For single boom application (and especially when spraying in a cross wind), there is some question whether off-target drift of sprayed crop protection agent is influenced by which boom is spraying and if direction of propeller rotation has any effect. An experiment was conducted to determine the effect of propeller wash rotation on aerial spray drift from turbine-powered aircraft. Spray samplers were placed at three sample lines to collect drift fallout and air-entrained particles 104, 134, 195, and 317 meters downwind, perpendicular to the flight path. An aqueous mixture of malathion was applied from the aircraft through fifty hollow cone nozzles. Five total replications were conducted over two days. Each replication had four treatment combinations of actively spraying boom and airplane direction. Results showed that neither active boom nor boom location (upwind or downwind) was statistically significant for either sampling method at the 0.05 level. Blocking the study to account for weather differences increased statistical precision. Thus when analysis was limited to the second day of testing, propeller wash direction was significant at the 0.10 level for the fallout sheets (P = 0.0773), and at the 0.05 level for high volume (Hi-Vol) air samplers (P = 0.0200). Higher concentrations occurred when propeller wash spiraled downwind. Based on results of this study, recommendations for pilots spraying with a single boom near a boundary is to spray so that propeller wash rotation occurs upwind
Fluid flow properties of the Wilhelmøya Subgroup, a potential unconventional CO2 storage unit in central Spitsbergen
The Upper Triassic to Middle Jurassic Wilhelmøya Subgroup forms one of the more suitable reservoir units on the Norwegian Arctic archipelago of Svalbard. The target siliciclastic storage unit, which is encountered at approx. 670 m depth at the potential injection site in Adventdalen, central Spitsbergen, is a severely under-pressured (at least 35 bar), tight and compartmentalised reservoir with significant contribution of natural fractures to permeability. In this contribution, we characterise the 15–24 m-thick Wilhelmøya Subgroup storage unit using both borehole and outcrop data and present water-injection test results that indicate the presence of fluid-flow barriers and the generation of new, and propagation of pre-existing natural fractures during injection. Whole core samples from drillcores and outcrops were sampled for pore network characterisation and analysed using high-resolution X-ray computed tomography (Micro-CT). We demonstrate that heterogeneities such as structural discontinuities, igneous bodies and lateral facies variations, as examined in well core and equivalent outcrops, will strongly influence fluid flow in the target reservoir, both by steering and baffling fluid migration. Many of these heterogeneities are considered to be subseismic, and their detailed characterisation is important to predict subsurface CO2 storage potential and optimise injection strategy.publishedVersio
Feasibility and preliminary efficacy of the effects of flavanoid-rich purple grape juice on the vascular health of childhood cancer survivors: a randomized, controlled crossover trial.
BACKGROUND: Childhood cancer survivors have an increased risk of developing cardiovascular disease following treatment, yet few interventions have been evaluated to reduce this risk. Purple grape juice (pGJ), a rich source of flavonoids with antioxidant properties, has been shown in adults to reduce oxidative stress and improve endothelial function. We examined the effects of supplementing meals with pGJ on microvascular endothelial function and markers of oxidative stress and inflammation in 24 cancer survivors (ages 10–21 years). PROCEDURE: In a randomized controlled crossover trial consisting of two, 4 week intervention periods, each preceded by a 4 week washout period, subjects received in random order 6 ounces twice daily of pGJ and clear apple juice (cAJ; similar in calories but lower in flavonoids). Measurements were obtained before and after each supplementation period; change was evaluated using mixed effects ANOVA. RESULTS: pGJ did not improve endothelial function, measured using digital reactive hyperemia, compared with cAJ (mean change: pGJ 0.06, cAJ 0.22; difference of mean change [95% CI]: −0.16 [−0.42 – 0.11], P = 0.25). No significant changes in plasma concentrations of oxidized-LDL, myeloperoxidase, or high sensitivity C-reactive protein were observed. CONCLUSION: After 4 weeks of daily consumption of flavonoid-rich pGJ, no measurable change in vascular function was observed in these childhood cancer survivors. Pediatr Blood Cancer 2014;61:2290–2296
Evaluation of traditional and novel measures of cardiac function to detect anthracycline-induced cardiotoxicity in survivors of childhood cancer
Dexrazoxane for reducing anthracycline-related cardiotoxicity in children with cancer: An update of the evidence
Advances in treating childhood cancers over the past 40years have more than doubled 5-year survival rates. More effective use of chemotherapeutic agents has been key to this success. However, the increase has come at a price: chronic conditions are significantly more prevalent in long-term survivors of childhood cancer than they are in the general population, and managing these survivors can be challenging. In patients receiving anthracyclines, cardiotoxicity is the leading cause of morbidity and mortality after relapse and second malignancies. More than 50% of patients exposed to anthracyclines exhibit some form of cardiac dysfunction within 20years after completing chemotherapy, and about 5% develop heart failure. These conditions greatly reduce the quality of life of the individual and also consume substantial amounts of healthcare resources. Dexrazoxane has been used to reduce anthracycline-related cardiotoxicity in children with cancer, but in 2011, the European Medicines Agency determined, on what it acknowledged were limited data, that dexrazoxane was contraindicated in children. Here, we review the evidence for the clinical effects of dexrazoxane in children. Studies published since 2011 have confirmed the efficacy of dexrazoxane in preventing or reducing anthracycline-related cardiotoxicity in children with cancer, and no new evidence of increased risks for recurrence of primary or second malignancies, or reductions in antitumor efficacy has been reported. As a result, we believe that dexrazoxane should be available to children with high-risk cancers to reduce the risk of cardiotoxicity associated with high-dose anthracycline treatment