612 research outputs found
Early Season Soybean Insects: Past Problems and Future Risk
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)
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
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
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
Recommended from our members
Engineering current density over 5 kA mm-2 at 4.2 K, 14 T in thick film REBCO tapes
We report on remarkably high in-field performance at 4.2 K achieved in >4 μm thick rare earth barium copper oxide (REBCO) samples with Zr addition. Two different samples have been measured independently at Lawrence Berkeley National Laboratory and the National High Magnetic Field Laboratory, achieving critical current densities (J ) of 12.21 MA cm and 12.32 MA cm at 4.2 K, 14 T (), respectively, which corresponds to equivalent critical current (I ) values of 2247 and 2119 A/4 mm. These I values are about two times higher than the best reported performance of REBCO tapes to date and more than five times higher than the commercial HTS tapes reported in a recent study. The measured J values, with a pinning force of ∼1.7 T N m are almost identical to the highest value reported for thin (∼1 μm thick) REBCO at the field and temperature, but extended to very thick (>4 μm) films. This results in an engineering current density (J ) above 5 kA mm at 4.2 K, 14 T, which is more than five times higher than Nb Sn and nearly four times higher than the highest reported value of all superconductors other than REBCO at this field and temperature. The reported results have been achieved by utilizing an advanced metal organic chemical vapor deposition system. This study demonstrates the remarkable level of in-field performance achievable with REBCO conductors at 4.2 K and strong potential for high-field magnet applications. c c c c e 3 -2 -2 -3 -
Patterns of Natural and Human-Caused Mortality Factors of a Rare Forest Carnivore, the Fisher (Pekania pennanti) in California.
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
Imported Longhorned Weevil (Coleoptera: Curculionidae) Injury to Soybean: Physiological Response and Injury Guild-Level Economic Injury Levels
Recommended from our members
Tripled critical current in racetrack coils made of Bi-2212 Rutherford cables with overpressure processing and leakage control
We fabricated three racetrack coils (RC1, RC2, and RC3) from Bi-2212 Rutherford cables (17-strand, thickness × width = 1.44 mm × 7.8 mm, strand diameter = 0.8 mm) and applied overpressure processing heat treatment (OPHT). The quench currents of RC1 and RC2 reached 5268 A and 5781 A, respectively, despite them still, surprisingly, exhibiting some Bi-2212 leakage to the surface. After removing most of the leakages using a simple-to-implement insulation scheme, the quench current of RC3 improved to 6485 A, which is about three times the average quench current of a dozen racetrack coils that had been fabricated and reacted using the conventional 1 bar heat treatment. The results confirm the effectiveness of the OPHT technology and the new leakage control scheme for coils made from Bi-2212 Rutherford cables. Coils exhibited an increased quench current with increasing the current ramp rate from 5 to 200 A s ; they were quite stable against point and transient disturbances, and were capable of adsorbing persistent Joule heating at ∼80 mW for >15 s before quenching. These behaviors are different from Nb-Ti and Nb Sn accelerator magnets. Overall, our results provide a critical evaluation and verification of Bi-2212 wire and magnet technologies (wire, insulation, heat treatment, coil fabrication, and coil operation), reveal crucial new stability features of Bi-2212 magnets, and demonstrate technological options for it to become a practical high-field magnet technology. -1
- …