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Application Data (application + data)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Risk assessment of Magnacide® H herbicide at Río Colorado irrigation channels (Argentina). tier 3: Studies on native species

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2007
Andrés Venturino
Abstract We evaluated the potential environmental risk of the herbicide Magnacide® (Baker Petrolite, TX, USA) using native species from Argentina, representing the ecosystem at the Irrigation Corporation (CORFO) channels at the Colorado River mouth, Buenos Aires, Argentina. Six species including fish, toads, snails, crustaceans, and insects were selected to perform studies on acute toxicity and repeated exposure effects. Magnacide H susceptibility ranking was Bufo arenarum (lethal concentration 50 [LC50] = 0.023 mg/L), Onchorhynchus mykiss (LC50 = 0.038 mg/L), Heleobia parchappii (LC50 = 0.21 mg/L), Hyalella curvispina (LC50 = 0.24 mg/L), Simulium spp. (LC50 = 0.60 mg/L), and Chironomus spp. (LC50 = 2.83 mg/L). The risk limit of 10th percentile (0.013 mg/L) determined by probit analysis on sensitivity distribution was similar to the one calculated from literature data. Risk assessment based on field application data suggested lethal exposures for more than 70 to 90% of the species up to 20 km downstream from the application point. Repeated exposures to Magnacide H of amphibian larvae at the lowest-observed-effect concentration caused some effects during the first exposure, but without cumulative effects. Amphipods were insensitive to repeated exposures, showing no cumulative effects. Whether short-term exposures may result in long-term sublethal effects on the organism's life history was not addressed by these laboratory tests. In conclusion, tier 3 studies indicate that Magnacide H application schedule is extremely toxic for most native species at CORFO,Río Colorado channels, representing a high potential risk in the environment. The real environmental impact must be addressed by field studies at tier 4 giving more information on population effects and communities. [source]

An In Situ Device to Measure Oxygen in the Vadose Zone and in Ground Water: Laboratory Testing and Field Evaluation

GROUND WATER MONITORING & REMEDIATION, Issue 2 2008
Bradley M Patterson
Oxygen probes developed to measure in situ oxygen concentrations in gaseous and aqueous environments were evaluated in laboratory tests and during long-term field evaluation trials at contaminated sites. The oxygen probes were shown to have a linear calibration and to be accurate compared to conventional dissolved oxygen electrodes and gas chromatography, both of which require labor-intensive sample collection and processing. The probes, once calibrated, required no maintenance or recalibration for up to a period of 7 years in low-oxygen environments, demonstrating long-term stability. Times to achieve 90% of the stabilized concentration (t90) after a step change in aqueous oxygen concentration were 100,120 min in laboratory experiments and up to 180 min in field experiments, which is adequate for monitoring subsurface changes. Field application data demonstrated that the oxygen probes could monitor oxygen concentrations in hydrocarbon-contaminated ground water to a depth of 20 m below the water table or in pyritic vadose zones over extended periods. During bioremediation field trials, oxygen monitoring enabled estimation of oxygen utilization rates by microorganisms and hydrocarbon biodegradation rates. Also, probes were able to monitor the development of ground water desaturation during air sparging trials, enabling the automated assessment of the distribution of injected air. [source]

Technological Diversity and Jacobs' Externality Hypothesis Revisited

GROWTH AND CHANGE, Issue 2 2005
OLOF EJERMO
ABSTRACT Recent empirical evidence strongly supports Jacobs's (1969) externality hypothesis that urban diversity provides a more favorable environment for economic development than urban specialization. In order to correctly gauge Jacobs's hypothesis, economic development should be understood as a result of innovations. Furthermore, a relevant diversity measure should take into account the degree of diversity of the inherent classes (e.g. pharmaceuticals are closer to chemicals than to forestry). These ideas are tested using regionally classified Swedish patent application data as a measure of innovativeness. Patent data are also used to reflect technological diversity. The results show that the number of patent applications in Swedish regions is highly and positively dependent on regional technological specialization, quite the opposite of Jacobs's prediction. This paper raises general questions about earlier empirical results. It is concluded that the size of regions is an important factor to consider, since this in itself may affect patenting intensity and technological diversity. [source]

Application of chemical and biological agents for the management of frosty pod rot (Moniliophthora roreri) in Costa Rican cocoa (Theobroma cacao)

ANNALS OF APPLIED BIOLOGY, Issue 2 2005
R.P. Bateman
Abstract This article describes two field trials carried out at La Lola, Costa Rica, to assess control measures against frosty pod rot of cocoa (Theobroma cacao) caused by Moniliophthora (Crinipellis) roreri. In the first, factorial, trial the control agents were applied using motorised mistblowers (MMs) and hydraulic sprayers fitted with a narrow angle cone nozzle. There was an interaction between agents and application methods; together with previous application data for the most active fungicide (copper hydroxide), these trials indicate that best yields are achieved with sprays that maximise deposits on pods. We describe the droplet size spectra produced by a Stihl SR400 MM under a range of conditions because this has become the standard method of fungicide application in this series of trials at La Lola. The factor that had the largest effect on droplet size spectrum was the presence or the absence of a detachable baffle plate in front of the air-shear nozzle. In both trials described here, MMs were fitted with baffle plates, a formulation pump and restrictor transmitting 550 mL min,1 to deliver an estimated equivalent of 190 L ha,1. Copper hydroxide as prophylactic applications at 1500 g a.i. ha,1 have, to date, shown the most consistent (but incomplete) improvement in healthy pod yield. Use of copper fungicides may be cost effective when farm-gate cocoa prices exceed approximately $1.25 kg,1. In these trials, isolates of the hyperparasitic fungi Clonostachys byssicola and Trichoderma asperellum and two off-patent triazole fungicides (bitertanol and triadimenol) made no significant improvement to healthy yields. The systemic oxathiin fungicide flutolanil, at a dosage of 300 g a.i. ha,1, appears to protect pods substantially at early stages but gives proportionately less control of M. roreri than copper at later stages of pod development. [source]