612 research outputs found

    Early Season Soybean Insects: Past Problems and Future Risk

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    The spring of 1994 saw many early season insect problems on soybeans in Iowa and, indeed, across much of the Midwest. Although early season problems on soybeans are not uncommon, certainly the scale of problems we saw in 1994 was unusual. Undoubtedly, many of these problems followed from weather, in particular the heavy rains of 1993. In this paper, we will briefly review some of the reasons behind the events we saw in 1994 and focus on the potential for future problems and their management. In particular, with the possibility of many acres coming into production out of the Conservation Reserve Program (CRP), there is a potential for specific insect problems that should be recognized

    Ecophysiological Significance of CO2-Recycling via Crassulacean Acid Metabolism in Talinum Calycinum Englem. (Portulacaceae)

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    This is the publisher's official version, also available electronically from: http://www.plantphysiol.org/content/86/2/562.full.pdfHigh levels of variability in gas exchange characteristics and degree of CAM-cycling were found in the same and different individuals of Talinum calycinum Engelm. collected from rock outcrops in Missouri. Differences in CO, assimilation were mostly correlated with differences in shoot conductance to C02 not shoot internal C02 concentration. As found previously, CAM acid fluctuations were evident in well-watered plants exhibiting C3 gas exchange patterns (CAM-cycling) and also in drought-stressed plants with stomata closed, or nearly so, day and night (CAM-idling). Drought stress also resulted in rapid stomatal closure, conserving water during droughts. Maximal CO, uptake rates occurred below 35°C; higher temperatures induced decreases in CO. assimilation and conductance while shoot internal C02 concentrations remained similar. Plant water-use-efficiency was severely curtailed at temperatures above 30°C. Tissue acid fluctuations were the result of changes in malic acid concentrations. Calculations of the amount of water potentially conserved by CAM-cycling yielded values of approximately 5 to 4 4% of daytime water loss. Thus, CAM-cycling may be an important adaptation minimizing water loss by perennial succulents growing in shallow soil on rock outcrops

    Gravity Fed Water System

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    The Gravity Fed Water Project aims to provide direct access to safe and clean water to about 150 people in Sipacapa, Guatemala by using gravity to transport water from groundwater seeps down a mountain to the community. The project partners with the Mennonite Central Committee. Concrete intake structures will be built for various groundwater seeps, then water from those will be combined into one large concrete intake structure. The water will then be piped down to a concrete water tank which will help to store enough water for a day\u27s use for the village. There will then be piping going to two different locations which will each have a storage tank. The Gravity Fed Water team plans to travel to the site to install part of the system in the future, although the date is uncertain. While in Guatemala, onsite water testing will be done for bacterial coliforms and the intake structure and the piping to the first storage tank will be built.https://mosaic.messiah.edu/engr2020/1010/thumbnail.jp

    Magnetic switching in granular FePt layers promoted by near-field laser enhancement

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    Light-matter interaction at the nanoscale in magnetic materials is a topic of intense research in view of potential applications in next-generation high-density magnetic recording. Laser-assisted switching provides a pathway for overcoming the material constraints of high-anisotropy and high-packing density media, though much about the dynamics of the switching process remains unexplored. We use ultrafast small-angle x-ray scattering at an x-ray free-electron laser to probe the magnetic switching dynamics of FePt nanoparticles embedded in a carbon matrix following excitation by an optical femtosecond laser pulse. We observe that the combination of laser excitation and applied static magnetic field, one order of magnitude smaller than the coercive field, can overcome the magnetic anisotropy barrier between "up" and "down" magnetization, enabling magnetization switching. This magnetic switching is found to be inhomogeneous throughout the material, with some individual FePt nanoparticles neither switching nor demagnetizing. The origin of this behavior is identified as the near-field modification of the incident laser radiation around FePt nanoparticles. The fraction of not-switching nanoparticles is influenced by the heat flow between FePt and a heat-sink layer

    Patterns of Natural and Human-Caused Mortality Factors of a Rare Forest Carnivore, the Fisher (Pekania pennanti) in California.

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    Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti), a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%), natural disease (16%), toxicant poisoning (10%) and, less commonly, vehicular strike (2%) and other anthropogenic causes (2%) were causes of mortality observed. We documented both an increase in mortality to (57% increase) and exposure (6%) from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species
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