3,090 research outputs found
Foundations of Programming Languages
This clearly written textbook provides an accessible introduction to the three programming paradigms of object-oriented/imperative, functional, and logic programming. Highly interactive in style, the text encourages learning through practice, offering test exercises for each topic covered. Review questions and programming projects are also presented, to help reinforce the concepts outside of the classroom. This updated and revised new edition features new material on the Java implementation of the JCoCo virtual machine
RESULTS OF A FARM AND MARKET SURVEY FOR HMONG SPECIALTY CROP FARMERS IN THE MINNEAPOLIS, ST. PAUL METRO AREA
This report is part of a larger project, "Risk Management Education and Farm Management Development Program for Hmong Specialty Crop Farmers in the Minneapolis, St. Paul Metro Area," funded by the Risk Management Agency, U.S. Department of Agriculture. The project was designed to assist Hmong farmers in the Twin Cities area in improving their production and management practices so they are able to increase their economic viability and reduce their exposure to risk. As part of the overall project, 62 Hmong farmers and 69 customers at farmers markets were surveyed to determine the local specialty crop production and market conditions. The findings of these 2 surveys are contained in the report. The median size of the 62 farms surveyed farms was 3 acres. Forty-two percent of those farmers responding reported total farm product sales between 8,999. Few farmers indicated they were familiar with crop insurance programs. Sixty-eight percent of the 19 farmers responding (or 21% of the 62 surveyed) said they were familiar with multi-peril crop insurance (MPCI). Only 12% of the 50 farmers responding had bought crop insurance in 2002. The most frequently indicated needs for future education programs were production oriented: weed control, insect control, fertilization, and pesticide safety. All of the 69 customers surveyed regularly bought some kind of vegetables or herbs. Over half of the customers bought potatoes, snap beans, peppers, sweet corn, carrots, cucumbers, basil, and winter squash. Eighty-eight percent of customers indicated they typically spend between 29 on vegetables and herbs during each visit to a farmers' market.Crop Production/Industries,
170 Nanometer Nuclear Magnetic Resonance Imaging using Magnetic Resonance Force Microscopy
We demonstrate one-dimensional nuclear magnetic resonance imaging of the
semiconductor GaAs with 170 nanometer slice separation and resolve two regions
of reduced nuclear spin polarization density separated by only 500 nanometers.
This is achieved by force detection of the magnetic resonance, Magnetic
Resonance Force Microscopy (MRFM), in combination with optical pumping to
increase the nuclear spin polarization. Optical pumping of the GaAs creates
spin polarization up to 12 times larger than the thermal nuclear spin
polarization at 5 K and 4 T. The experiment is sensitive to sample volumes
containing Ga. These results
demonstrate the ability of force-detected magnetic resonance to apply magnetic
resonance imaging to semiconductor devices and other nanostructures.Comment: Submitted to J of Magnetic Resonanc
Identification of a novel retroviral gene unique to human immunodeficiency virus type 2 and simian immunodeficiency virus SIVMAC
Human and simian immunodeficiency-associated retroviruses are extraordinarily complex, containing at least five genes, tat, art, sor, R, and 3' orf, in addition to the structural genes gag, pol, and env. Recently, nucleotide sequence analysis of human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus SIVMAC revealed the existence of still another open reading frame, termed X, which is highly conserved between these two viruses but absent from HIV-1. In this report, we demonstrate for the first time that the X open reading frame represents a functional retroviral gene in both HIV-2 and SIVMAC and that it encodes a virion-associated protein of 14 and 12 kilodaltons, respectively. We also describe the production of recombinant TrpE/X fusion proteins in Escherichia coli and show that sera from some HIV-2-infected individuals specifically recognize these proteins
Photonic Crystal Vertical Cavity Lasers
Photonic crystal confinement in vertical cavity surface-emitting lasers (VCSELs) is a robust and reliable technology for achieving operation in the fundamental lateral mode and is potentially applicable to a variety of materials systems and operating wavelengths. We demonstrate photonic crystal VCSELs operating in a single transverse mode with over 30 dB side mode suppression and over 1 mW of output power. These lasers have been subjected to a post-process technique to introduce the etched holes making up the photonic crystals that surround a centralized defect in which lasing occurs. We also show that coupling between adjacent defects in a photonic lattice is possible, further increasing the power available in the devices
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