Field measurement of penetrator seismic coupling in sediments and volcanic rocks

Field experiments were conducted to determine experimentally how well a seismometer installed using a penetrator would be coupled to the ground. A dry lake bed and a lava bed were chosen as test sites to represent geological environments of two widely different material properties. At each site, two half-scale penetrators were fired into the ground, a three-component geophone assembly was mounted to the aft end of each penetrator, and dummy penetrators were fired at various distances to generate seismic signals. The recorded signals were digitized, and cross-spectral analyses were performed to compare the observed signals in terms of power spectral density ratio, coherence and phase difference. The analyses indicate that seismometers deployed by penetrators will be as well coupled to the ground as are seismometers installed by conventional methods for the frequency range of interest in earthquake seismology, although some minor differences were observed at frequencies near the upper limit of the frequency band

Study of proton radiation effects on solar vehicle electronic system

Radiation effects on electronic equipment of solar spacecraft - shielding requirement

Cheeseheads and Longhorns: Why Texas Should Follow Wisconsin’s Lead in the Treatment of Limited Liability Company Member Interests as Securities

The limited liability company has become one of the more attractive business associations, both for legitimate enterprises seeking flexibility in structure, shields from personal liability for company debts and obligations, and tax advantages, and for the not-so-legitimate enterprises seeking shelter from personal liability for taking advantage of the unwary. In order to assist and protect the investing public and to provide certainty and structure for business owners, Texas should amend its current statutory scheme to mandate the treatment of certain LLC interests as securities, modeling this legislation after the Wisconsin approach-a three-tiered method of defining an LLC as a security. Part II of this Comment will describe the LLC entity and its history, enumerate its advantages, and give a brief description of the 1997 IRS taxation changes. Part III will delve into the much-debated question whether LLC member interests are securities and will describe the benefits of treating them as such. Part IV will describe the Texas treatment of LLC member interests to date and the problems that accompany that treatment. Part V will describe some other states\u27 treatment of LLC interests and how the Wisconsin approach is preferable. Part VI will enumerate the proposed changes to Texas law modeled after those states\u27 regulations

Bee diversity of three Appalachian shale barren sites

Insect pollination is vital to ecosystem function. However, climate change, habitat loss, pesticides, and a variety of other anthropogenic sources are contributing to a decline in pollinator diversity. Fragile small ecosystems with a high composition of specialized plant species that rely on specific pollinators such as Appalachian shale barrens, are especially at risk of losing biodiversity. This study combines the use of active sweep net sampling of endemic shale barren forbs and passive trap methods over the course of a bloom season (April-August) in three barren sites to identify bee community populations and visitation relationships between pollinator species and endemic flowers. From all samples, 72 species of bees were identified. Both Shannon’s Diversity Index and a rarefaction analysis of Month x Site indicate May is a time of highest species diversity for bees. Among individuals caught visiting flowers, June was indicated as a time of highest flower visitations. A pollinator network was created to identify unique relationships between pollinators and flowers, providing information on species of particular value to those systems for future conservation purposes. Species records from this survey contribute to expanding the currently limited data on bee species range, life history, and flower associations

Health strategies for the control of childhood malnutrition

Malnutrition is the most important cause of morbidity and mortality of young children in non-industrialized poor countries. The control of protein - energy malnutrition is more complex than the prevention of most other common killing diseases of children. It requires a multi-disciplinary approach including involvement of departments and staff responsible for agriculture, social services, education, economic development, health and possibly others. The aetiology of the problem is complex and is closely related to poverty, deprivation, ignorance and prevalent infectious diseases. Intervention programmes should be considered a legitimate part of national and local development plans. This paper, while briefly discussing the planning of nutrition programmes, deals primarily with those interventions in which health personnel play a leading role. The need for base-line data, for continuing surveillance and for planned evaluation of programmes is discussed. The major part of the paper consists of a critical examination of the three levels of treatment and prevention now commonly favoured: the hospital, the nutrition rehabilitation centre and the health clinic

A new approach to upscaling fracture network models while preserving geostatistical and geomechanical characteristics

A new approach to upscaling two-dimensional fracture network models is proposed for preserving geostatistical and geomechanical characteristics of a smaller-scale “source” fracture pattern. First, the scaling properties of an outcrop system are examined in terms of spatial organization, lengths, connectivity, and normal/shear displacements using fractal geometry and power law relations. The fracture pattern is observed to be nonfractal with the fractal dimension D ≈ 2, while its length distribution tends to follow a power law with the exponent 2 < a < 3. To introduce a realistic distribution of fracture aperture and shear displacement, a geomechanical model using the combined finite-discrete element method captures the response of a fractured rock sample with a domain size L = 2 m under in situ stresses. Next, a novel scheme accommodating discrete-time random walks in recursive self-referencing lattices is developed to nucleate and propagate fractures together with their stress- and scale-dependent attributes into larger domains of up to 54 m × 54 m. The advantages of this approach include preserving the nonplanarity of natural cracks, capturing the existence of long fractures, retaining the realism of variable apertures, and respecting the stress dependency of displacement-length correlations. Hydraulic behavior of multiscale growth realizations is modeled by single-phase flow simulation, where distinct permeability scaling trends are observed for different geomechanical scenarios. A transition zone is identified where flow structure shifts from extremely channeled to distributed as the network scale increases. The results of this paper have implications for upscaling network characteristics for reservoir simulation

Brown-headed Cowbird Brood Parasitism in Bison-grazed and Ungrazed Tallgrass Prairie

The Brown-headed Cowbird (Molothrus ater has long been associated with bison (Bos bison) in North America on the Great Plains (Friedmann 1929). As a result, I anticipated that cowbirds would parasitize host nests more frequently in the presence of bison than in their absence. I predicted that several common ground-nesting avian species, Dickcissels (Spiza americana), Grasshopper Sparrows (Ammodramus savannarum), and Eastern Meadowlarks (Sturnella magna), would suffer higher frequencies of brood parasitism in bison-grazed habitat than in ungrazed habitat on the tallgrass Konza Prairie Research Natural Area, located in northeastern Kansas. The frequency of cowbird parasitism for all species combined was significantly higher in bison-grazed (0.69) than in ungrazed habitat (0.44) (p =0.044, X2 = 4.061, df =1). These results are consistent with the hypothesis and suggestion that bison-grazed habitat may be a more optimal site for cowbird brood parasitism than ungrazed habitat. I pose two principal explanations for the higher frequency of parasitism observed in the bison-grazed area. First, cowbirds may be able to forage more efficiently in the bison-grazed area, indirectly inflating parasitism frequencies by conferring a variety of energetic and nutritional advantages upon the females. Second, the cowbirds\u27 abilities to find and parasitize nests may be enhanced by the shorter, less dense grass characteristic of grazed habitat. Further studies investigating the conservation implications of this phenomenon are merited

Endothelial HO-1 induction by model TG-rich lipoproteins is regulated through a NOX4-Nrf2 pathway

Circulating levels of chylomicron remnants (CMRs) increase postprandially and their composition directly reflects dietary lipid intake. These TG-rich lipoproteins likely contribute to the development of endothelial dysfunction, albeit via unknown mechanisms. Here, we investigated how the FA composition of CMRs influences their actions on human aortic endothelial cells (HAECs) by comparing the effects of model CMRs—artificial TG-rich CMR-like particles (A-CRLPs)—containing TGs extracted from fish, DHA-rich algal, corn, or palm oils. HAECs responded with distinct transcriptional programs according to A-CRLP TG content and oxidation status, with genes involved in antioxidant defense and cytoprotection most prominently affected by n-3 PUFA-containing A-CRLPs. These particles were significantly more efficacious inducers of heme oxygenase-1 (HO-1) than n-6 PUFA corn or saturated FA-rich palm CRLPs. Mechanistically, HO-1 induction by all CRLPs requires NADPH oxidase 4, with PUFA-containing particles additionally dependent upon mitochondrial reactive oxygen species. Activation of both p38 MAPK and PPARβ/δ culminates in increased nuclear factor erythroid 2-related factor 2 (Nrf2) expression/nuclear translocation and HO-1 induction. These studies define new molecular pathways coupling endothelial cell activation by model CMRs with adaptive regulation of Nrf2-dependent HO-1 expression and may represent key mechanisms through which dietary FAs differentially impact progression of endothelial dysfunction