Effect of day time climatic conditions associated with different 2,4-D formulations on spray deposition and weed control

Abstract

The aim of this study was to evaluate the effect of time of the day and their associated climatic conditions on spray deposition of two 2,4-D formulations, as well as the influence on weed control. The experiment was installed in the field in complete randomized design. Treatments were arranged in factorial design 8?×?2, with 20 repetitions. First factor corresponded to different application time (1:00, 4:00, 7:00, 10:00, 13:00, 16:00, 19:00, and 22:00) with their respective climatic conditions. The second factor consisted of two formulations of 2,4-D applied at 776?g a.e. ha^?1 (2,4-D amine and 2,4-D choline salt with Colex-D? Technology) + glyphosate (816?g a.e. ha^?1). There was more spray deposition when 2,4-D choline formulation was used, and such differences were more evident for applications performed under adverse climatic conditions. More spray deposition was found in applications performed at times of day with more favorable temperature and humidity of the air conditions. Only the initial control of the evaluated species was affected by the time of application.     

I will not go,I cannot go: cultural and social limitations of disaster preparedness in Asia,Africa, and Oceania

While much work has been invested in addressing the economic and technical basis of disaster preparedness, less effort has been directed towards understanding the cultural and social obstacles to and opportunities for disaster risk reduction. This paper presents local insights from five different national settings into the cultural and social contexts of disaster preparedness. In most cases, an early warning system was in place, but it failed to alert people to diverse environmental shocks. The research findings show that despite geographical and typological differences in these locations, the limitations of the systems were fairly similar. In Kenya, people received warnings, but from contradictory systems, whereas in the Philippines and on the island of Saipan, people did not understand the messages or take them seriously. In Bangladesh and Nepal, however, a deeper cultural and religious reasoning serves to explain disasters, and how to prevent them or find safety when they strike.     

Revaluation of a Soy Protein By-product in Eco-friendly Bioplastics by Extrusion

Journal of Polymers and the Environment - Agri-food waste and by-products are being increasingly revalued, exploiting their potential. One of the attractive alternatives is their use as raw...     

Corona ion induced atmospheric potential gradient perturbations near high voltage power lines

High voltage power lines are known to produce corona ions that can be carried from the line by the wind, progressively attaching to ambient aerosol particles and causing fluctuations in the Earth’s atmospheric potential gradient. A fixed site monitoring station was installed near two power lines, which recorded the potential gradient at 1 s intervals and the ambient weather conditions every 10 min. The station ran continuously from January 2007 to December 2008, accumulating long-term data. Results from 2008 show an increase in potential gradient variability when a wind is blowing across the power lines towards the station, indicating that corona ions may be present in this environment.     

Modifications of the transition flow reactor theory for the more accurate measurement of nitric acid and nitrate and ammonium ions

Sixty five samples were taken with a Transition Flow Reactor (TFR) for the measurement of nitric acid (HNO₃) and nitrate particulates (NO ₃ ⁻ ), in a central Athens street having a heavy traffic density, between February 1989 and February 1990. It was established that the TFR theory overestimated HNO₃ and underestimated NO ₃ ⁻ . This is caused by the retention of a fraction of the NO₂ and a fraction of the HNO₂ as NO ₂ ⁻ on the sampler's nylon linear. NO ₂ ⁻ is in turn oxidized to NO ₃ ⁻ and this is determined as HNO₃. Two modifications of the TFR theory are proposed for a better estimation of the HNO₃ and NO ₃ ⁻ . With the first modification HNO₃ is estimated as being equal to the smaller of two values: HNO_{3 TFR} and the value calculated if it is considered that 91% of HNO₃ is retained by the nylon filter. The second modification was based on the quantification of the effect of NO₂ on the concentrations of HNO₃ and NO ₃ ⁻ . This modification is an improvement on the first one and enables the calculation of a lower limit for the concentration of HNO₂. Both modifications improve the accuracy of the TFR sampler in measuring HNO₃ and NO ₃ ⁻ , without altering it structurally. It was also found that the nylon filter partially retains some NH₃, causing a negative error in the measurement of NH ₄ ⁺ with the TFR. The extent of NH₃ retention on the nylon filter is proportional to the HNO₃ concentration. This error must be taken into account whenever NH ₄ ⁺ is being determined.     

Prospects for repellent in pest control: current developments and future challenges

The overall interest in environmentally safe pest control methods and the rise of insecticide resistance in pest populations have prompted medical and agricultural entomology research on insect repellents in recent years. However, conducting research on repellent is challenging for several reasons: (1) the different repellent phenomena are not well defined; (2) it is difficult to test for and quantify repellent; (3) the physiological mechanisms are poorly known; (4) the field efficacy appears to be highly variable. Here, we identified five different types of repellent: expellency, irritancy, deterrency, odor masking and visual masking, and described behavioral bioassays to differentiate between them. Although these categories are currently defined by their behavioral response to different stimuli, we suggest new definitions based on their mechanism of action. We put forward three main hypotheses on the physiological mechanism: (1) a dose effect that modifies the behavior, (2) a repellent mechanism with specific receptors, or (3) inhibition of the transduction of neural information.     

Fixism and conservation science

The field of biodiversity conservation has recently been criticized as relying on a fixist view of the living world in which existing species constitute at the same time targets of conservation efforts and static states of reference, which is in apparent disagreement with evolutionary dynamics. We reviewed the prominent role of species as conservation units and the common benchmark approach to conservation that aims to use past biodiversity as a reference to conserve current biodiversity. We found that the species approach is justified by the discrepancy between the time scales of macroevolution and human influence and that biodiversity benchmarks are based on reference processes rather than fixed reference states. Overall, we argue that the ethical and theoretical frameworks underlying conservation research are based on macroevolutionary processes, such as extinction dynamics. Current species, phylogenetic, community, and functional conservation approaches constitute short‐term responses to short‐term human effects on these reference processes, and these approaches are consistent with evolutionary principles.