Process controls introduction of selected impurities into semiconductor wafers

Modified three-step process controls the concentration of lithium diffused as a dopant into the base region of a diffused n-on-p silicon solar cell wafer. Part of the surface layer of the base region of the p-type silicon containing the diffused dopant is removed, prior to redistributing the remaining portion of the dopant into the bulk of the wafer

“Popping it” as family in Mosquitoes & Me: affective accumulation and Anzaldúan aesthetic consciousness in \u3ci\u3eCiencia Zurda\u3c/i\u3e

This article uses key concepts of Anzaldúan philosophy to describe the Mosquitoes & Me summer camp as ciencia zurda or left-handed science. It details a day-in-the-life portrait of Elena, a first-generation Latina middle schooler, as she experiences the opportunities that Mosquitoes & Me provided for self-other bridge crossing and radically relational, Nepantlan potential. Our discussion of Elena’s experiences in terms of Nepantlan principles of diversity, Affect, and spirit, as well as Affective accumulation and aesthetic consciousness, infuse an emotional and spiritual dimension to inquiry science- and responsive sciencecomplementarity and revisit a call for soul-centered, socially-transformative science. Este artículo utiliza conceptos clave de la filosofía de Anzaldúan para describir el campamento de verano Mosquitos & Me como ciencia zurda. Detalla un retrato del día a día en la vida de Elena, una estudiante de secundaria latinoamericana de primera generación, mientras experimenta las oportunidades que Mosquitoes & Me le brindó para cruzar el puente entre sí misma y el potencial Nepantla que es radicalmente relacional. Nuestra discusión sobre las experiencias de Elena en términos de los principios de Nepantla sobre diversidad, afecto y espíritu, así como la acumulación afectiva y la conciencia estética, infunden una dimensión emocional y espiritual a la complementariedad de la ciencia investigadora y la ciencia receptiva, y hacen un llamado por una ciencia centrada en el alma y socialmente transformadora

Solid-State Microwave Electronics

Contains reports on three research projects.National Aeronautics and Space Administration (Grant NGL 22-009-163)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E

Ecological Niche Modeling of Potential West Nile Virus Vector Mosquito Species in Iowa

Ecological niche modeling (ENM) algorithms, Maximum Entropy Species Distribution Modeling (Maxent) and Genetic Algorithm for Rule-set Prediction (GARP), were used to develop models in Iowa for three species of mosquito — two significant, extant West Nile virus (WNV) vectors (Culex pipiens L and Culex tarsalis Coquillett (Diptera: Culicidae)), and the nuisance mosquito, Aedes vexans Meigen (Diptera: Culicidae), a potential WNV bridge vector. Occurrence data for the three mosquito species from a state-wide arbovirus surveillance program were used in combination with climatic and landscape layers. Maxent successfully created more appropriate niche models with greater accuracy than GARP. The three Maxent species' models were combined and the average values were statistically compared to human WNV incidence at the census block group level. The results showed that the Maxent-modeled species' niches averaged together were a useful indicator of WNV human incidence in the state of Iowa. This simple method for creating probability distribution maps proved useful for understanding WNV dynamics and could be applied to the study of other vector-borne diseases

Evaluation of preservation methods for selected nutrients in ground water at the Idaho National Engineering Laboratory, Idaho

Water from 28 wells completed in the Snake River Plain aquifer at the Idaho National Engineering Laboratory (INEL) was sampled as part of the US Geological Survey`s quality-assurance program to determine the effect of different preservation methods on nutrient concentrations. Samples were preserved with filtration and with mercuric chloride and chilling, chilling only, or sulfuric acid and chilling. The samples were analyzed for ammonia, nitrite, nitrite plus nitrate, and orthophosphate by the US Geological Survey National Water Quality Laboratory. The study was done in cooperation with the US Department of Energy. The comparison between samples preserved with mercuric chloride and chilling and samples preserved by chilling only showed that all sample pairs were in statistical agreement. Results for ammonia and nitrite plus nitrate samples preserved with sulfuric acid and chilling were within the 95 percent confidence level of the results for the samples preserved by the other two methods and can be considered equivalent to them. Results of this study indicate that discontinuing the use of mercuric chloride as a preservation method for nutrients in water samples will not affect the comparability of data collected at the INEL before and after October 1, 1994

\u3ci\u3eTraumatomutilla\u3c/i\u3e André miscellanea: Revision of the bellica, bifurca, diabolica, and vitelligera species groups, and a new group for the new species \u3ci\u3eT. pilkingtoni\u3c/i\u3e Bartholomay and Williams (Hymenoptera: Mutillidae: Sphaeropthalminae: Dasymutillini)

Five small species groups of Traumatomutilla André, 1901 are revised. A new species, T. pilkingtoni Bartholomay and Williams sp. nov. (Argentina) is described and placed within its own species group. All known species of the bellica, diabolica, vitelligera, and bifurca species groups are redescribed. New synonymies are proposed for T. vitelligera (Gerstaecker, 1874) = Mutilla fascinata Smith, 1879, syn. nov.; = Traumatomutilla comata André, 1906, syn. nov. and for T. bifurca (Klug, 1821) = T. ira Casal, 1969, syn. nov. The lectotypes of Mutilla bifurca Klug, 1821 and Mutilla comata André, 1906 are designated. The hitherto unknown males of T. vitelligera and T. bifurca are diagnosed and described

Plant essential oils synergize various pyrethroid insecticides and antagonize malathion in Aedes aegypti

Pyrethroid resistance is a significant threat to agricultural, urban and public health pest control activities. Because economic incentives for the production of novel active ingredients for the control of public health pests are lacking, this field is particularly affected by the potential failure of pyrethroid‐based insecticides brought about by increasing pyrethroid resistance. As a result, innovative approaches are desperately needed to overcome insecticide resistance, particularly in mosquitoes that transmit deadly and debilitating pathogens. Numerous studies have demonstrated the potential of plant essential oils to enhance the efficacy of pyrethroids. The toxicity of pyrethroids combined with plant oils is significantly greater than the baseline toxicity of either oils or pyrethroids applied alone, which suggests there are synergistic interactions between components of these mixtures. The present study examined the potential of eight plant essential oils applied in one of two concentrations (1% and 5%) to enhance the toxicity of various pyrethroids (permethrin, natural pyrethrins, deltamethrin and β‐cyfluthrin). The various plant essential oils enhanced the pyrethroids to differing degrees. The levels of enhancement provided by combinations of plant essential oils and pyrethroids in comparison with pyrethroids alone were calculated and synergistic outcomes characterized. Numerous plant essential oils significantly synergized a variety of pyrethroids; type I pyrethroids were synergized to a greater degree than type II pyrethroids. Eight plant essential oils significantly enhanced 24‐h mortality rates provided by permethrin and six plant essential oils enhanced 24‐h mortality rates obtained with natural pyrethrins. By contrast, only three plant essential plants significantly enhanced the toxicity of deltamethrin and β‐cyfluthrin. Of the plant essential oils that enhanced the toxicity of these pyrethroids, some produced varying levels of synergism and antagonism. Geranium, patchouli and Texas cedarwood oils produced the highest levels of synergism, displaying co‐toxicity factors of \u3e 100 in some combinations. To assess the levels of enhancement and synergism of other classes of insecticide, malathion was also applied in combination with the plant oils. Significant antagonism was provided by a majority of the plant essential oils applied in combination with this insecticide, which suggests that plant essential oils may act to inhibit the oxidative activation processes within exposed adult mosquitoes

Biodistribution of degradable polyanhydride particles in Aedes aegypti tissues

Insecticide resistance poses a significant threat to the control of arthropods that transmit disease agents. Nanoparticle carriers offer exciting opportunities to expand the armamentarium of insecticides available for public health and other pests. Most chemical insecticides are delivered by contact or feeding, and from there must penetrate various biological membranes to reach target organs and kill the pest organism. Nanoparticles have been shown to improve bioactive compound navigation of such barriers in vertebrates, but have not been well-explored in arthropods. In this study, we explored the potential of polyanhydride micro- and nanoparticles (250 nm– 3 μm), labeled with rhodamine B to associate with and/or transit across insect biological barriers, including the cuticle, epithelium, midgut and ovaries, in female Ae. aeygpti mosquitoes. Mosquitoes were exposed using conditions to mimic surface contact with a residual spray or paint, topical exposure to mimic contact with aerosolized insecticide, or per os in a sugar meal. In surface contact experiments, microparticles were sometimes observed in association with the exterior of the insect cuticle. Nanoparticles were more uniformly distributed across exterior tissues and present at higher concentrations. Furthermore, by surface contact, topical exposure, or per os, particles were detected in internal organs. In every experiment, amphiphilic polyanhydride nanoparticles associated with internal tissues to a higher degree than hydrophobic nanoparticles. In vitro, nanoparticles associated with Aedes aegypti Aag2 cells within two hours of exposure, and particles were evident in the cytoplasm. Further studies demonstrated that particle uptake is dependent on caveolae-mediated endocytosis. The propensity of these nanoparticles to cross biological barriers including the cuticle, to localize in target tissue sites of interest, and to reach the cytoplasm of cells, provides great promise for targeted delivery of insecticidal candidates that cannot otherwise reach these cellular and subcellular locations