2,474 research outputs found
Safety Nets or Trampolines? Federal Crop Insurance, Disaster Assistance, and the Farm Bill
We review the implications of the 2007 Farm Bill for the risk management dimensions of U.S. agriculture and policy. Legislative proposals suggest significant changes in risk management policy, including the introduction of state or national revenue insurance. We also pursue an empirical analysis of the interrelationships of crop insurance, disaster relief, and farm profitability. We find an inverse relationship between disaster assistance and insurance purchases. Our analysis also suggests that farmers that buy insurance and that receive disaster payments tend to have higher returns to farming.crop insurance, disaster payments, Farm Bill, Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Risk and Uncertainty, Q18,
Herbivorous Insects and the Hawaiian Silversword Alliance: Coevolution or Cospeciation?
Numerous groups of herbivorous insects in the Hawaiian archipelago
have undergone adaptive radiations. R. C. L. Perkins collected and documented
species in nearly all of these groups. In this study I tested whether patterns of host
plant use by herbivorous insects can be explained by host plant history. I examined
a group of insects in the planthopper genus Nesosydne (Hemiptera: Delphacidae) that
feed on plants in the Hawaiian silversword alliance, many of which are endangered
or threatened. For these Nesosydne species feeding on the silversword alliance,
mitochondrial DNA sequence data revealed a statistically significant pattern of
cospeciation between these insects and their hosts. These planthoppers are highly
host-specific, with each species feeding on only one, or a few closely related, plant
species. Patterns of host plant use across the plant lineage, as well as within extensive
hybrid zones between members of the silversword alliance, suggest that planthopper
diversification parallels host plant diversification. Data collected thus far are consistent
with, but do not directly demonstrate, reciprocal adaptation. For other herbivorous
insects associated with members of the Hawaiian silversword alliance, patterns
of host plant use and evolutionary history are not yet well understood. However,
cospeciation appears not to be universal. For example, endemic flies in the family
Tephritidae (Diptera) are less host-specific and demonstrate host-switching. Research
is under way to reveal the mechanisms associated with cospeciation and host switching
for different insect groups associated with the Hawaiian silversword
alliance
Evaluation of the kinetics and mechanism of drug release from Econazole nitrate nanosponge loaded Carbapol Hydrogel
The objective of this study was to investigate the mechanism of release of econazole nitrate (EN) nanosponges loaded hydrogel and to compare it with EN hydrogel so as to develop an extended release topical drug delivery system of EN. Nanosponges of EN were prepared using ethyl cellulose and PVA by emulsion solvent evaporation method. On the basis of pharmacotechnical evaluation nanosponges with least particle size of 230.1 nm and good rheological properties were formulated as hydrogel (F1 – F7). In vitro drug release data of EN nanosponges loaded hydrogels in phosphate buffer pH 6.8 and 7.4 when analysed by GraphPad Prism software version 4.0 San Diego, USA best fitted the Makoid-2 Banakar model (R value greater than 0.98). The Korsmeyer-Peppas release exponent (n) ranged between 0.331 – 0.418, which confirmed diffusion as the principle mechanism of drug release. The release mechanism was further confirmed by calculating the ratio of exponents A/B ratio derived from the Kopcha model
On-Change Publishing of Database Resident Control System Data
The CERN accelerator control system is largely data driven, based on a distributed Oracle® database architecture. Many application programs depend on the latest values of key pieces of information such as beam mode and accelerator mode. Rather than taking the non-scalable approach of polling the database for the latest values, the CERN control system addresses this requirement by making use of the Oracle Advanced Queuing – an implementation based on JMS (Java Message Service) – to publish data changes throughout the control system via the CERN Controls Middleware (CMW). This paper describes the architecture of the system, the implementation choices and the experience so far
Happiness as stable extraversion : internal consistency reliability and construct validity of the Oxford Happiness Questionnaire among undergraduate students
The Oxford Happiness Questionnaire (OHQ) was developed by Hills and Argyle (2002) to provide a more accessible equivalent measure of the Oxford Happiness Inventory (OHI). The aim of the present study was to examine the internal consistency reliability, and construct validity of this new instrument alongside the Eysenckian dimensional model of personality. The Oxford Happiness Questionnaire was completed by a sample of 131 undergraduate students together with the abbreviated form of the Revised Eysenck Personality Questionnaire. The data demonstrated good internal consistency reliability (alpha = .92) and good construct validity in terms of positive association with extraversion (r = .38 p < .001) and negative association with neuroticism (r = −.57 p < .001). The kind of happiness measured by the OHQ is clearly associated with stable extraversion
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