Has the "Farm Problem" Disappeared? A Comparison of Household and Self-Employment Income Levels of the Farm and Nonfarm Self-Employed

This study tests the impact of household and demographic factors on the economic well-being of the farm and nonfarm self-employed using data from the Integrated Public Use Microdata Series. Parametric and nonparametric techniques are used to test for statistical differences in self-employment and household income levels. Further, household and demographic factors are tested for their effect on self-employment income using a censored tobit regression model. The farm self-employed report significantly higher levels of self-employment income. Results reveal that several household and demographic factors significantly impact self-employment income levels for the farm and nonfarm self-employed, with key differences in impacts.self-employment, farm households, Community/Rural/Urban Development,

Does Experience Determine Performance? A Meta-Analysis on the Experience-Performance Relationship

The impact of experience on entrepreneurial performance has been widely tested. Although experience is expected to positively impact performance, results are varied. This research synthesizes the current literature by determining systematic sources of variation through both exploratory and ordered probit analyses. Results reveal that start date for data collection and form of experience tested pose a major impact on the probability of obtaining a positive estimate for the experience-performance relationship. This research further emphasizes the need for tightened standards across the experience-performance literature in order to equip both academics and practitioners with better information.Entrepreneurship, Experience, Performance, Meta-Analysis, Agribusiness, Labor and Human Capital,

Thermal and structural modeling of superinsulation

Model permits direct physical measurement of the thermal response of critical components of space telescopes, thus providing flexibility for systems studies and design changes

Thermal and structural modeling of a large aperture space telescope Technical summary report, 22 Jun. - 22 Sep. 1968

Thermal and structural modeling for large aperture space telescop

Light structures phototroph, bacterial and fungal communities at the soil surface

The upper few millimeters of soil harbour photosynthetic microbial communities that are structurally distinct from those of underlying bulk soil due to the presence of light. Previous studies in arid zones have demonstrated functional importance of these communities in reducing soil erosion, and enhancing carbon and nitrogen fixation. Despite being widely distributed, comparative understanding of the biodiversity of the soil surface and underlying soil is lacking, particularly in temperate zones. We investigated the establishment of soil surface communities on pasture soil in microcosms exposed to light or dark conditions, focusing on changes in phototroph, bacterial and fungal communities at the soil surface (0–3 mm) and bulk soil (3–12 mm) using ribosomal marker gene analyses. Microbial community structure changed with time and structurally similar phototrophic communities were found at the soil surface and in bulk soil in the light exposed microcosms suggesting that light can influence phototroph community structure even in the underlying bulk soil. 454 pyrosequencing showed a significant selection for diazotrophic cyanobacteria such as Nostoc punctiforme and Anabaena spp., in addition to the green alga Scenedesmus obliquus. The soil surface also harboured distinct heterotrophic bacterial and fungal communities in the presence of light, in particular, the selection for the phylum Firmicutes. However, these light driven changes in bacterial community structure did not extend to the underlying soil suggesting a discrete zone of influence, analogous to the rhizosphere

Earthworms of Two Minnesota Forest Areas

This paper reviews Lumbricidae records for Minnesota and reports on two collections in northern areas of the state. The first site, Itasca State Park, lies to the northwest with Maple-basswood representative of climax forest to the south and southeast and Spruce-fir stands representative of climax forest to the north and northeast (Buell and Gordon 1945). The Cloquet Forestry Center (CFC); site of the other collection, is near Duluth, 150 miles to the east, where the forests are largely coniferous. Here seven forest types, as described by Wenstrom (1973), and known to be used by American woodcock (Philohela minor), were sampled

Use of a Smartphone for Improved Self-Management of Pulmonary Rehabilitation

Patients suffering from chronic respiratory disease need to follow a rehabilitative exercise programme, in order to self-manage their illness and improve quality of life. Adherence to the programme is highly dependent on professional support from a physiotherapist and hence declines when patients seek to self-manage in the home. A number of requirements were identified for a Smartphone-based application in which patients are supported remotely and given automatic feedback during exercise. An application is described which will improve adherence during pulmonary rehabilitation

Multimode pumping of optical parametric oscillators

Cataloged from PDF version of article.Calculations suggest that optical parametric oscillators (OPO’s) can be efficiently pumped using multimode, divergent pump sources. The influence of pump beam divergence and mode structure upon OPO performance is measured for both noncritical phase-matching, and OPO’s with walkoff. Multimode OPO pumping is shown to be efficient, provided appropriate nonlinear crystals and OPO cavities are employed; the nonlinear crystal must have sufficient angular acceptance to tolerate a divergent pump; the OPO cavity must support modes that match the divergence and spatial intensity characteristics of the pump. For low-order pump modes, the OPO can be made to match the mode of the pump. Higher order pump modes reduce the OPO efficiency, and cause a saturation of efficiency with increasing pump power. The efficiency is degraded in a similar fashion in the presence of walkoff. Multimode pumping is more difficult in longer OPO cavities due to increased buildup time of higher order OPO modes