44,872 research outputs found

    DNA extraction from museum specimens of parasitic Hymenoptera.

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    At the same time that molecular researchers are improving techniques to extract DNA from museum specimens, this increased demand for access to museum specimens has created tension between the need to preserve specimens for maintaining collections and morphological research and the desire to conduct molecular analyses. To address these concerns, we examined the suitability of non-invasive DNA extraction techniques on three species of parasitic Hymenoptera (Braconidae), and test the effects of body size (parasitoid species), age (time since collection), and DNA concentration from each extract on the probability of amplifying meaningful fragments of two commonly used genetic loci. We found that age was a significant factor for determining the probability of success for sequencing both 28S and COI fragments. While the size of the braconid parasitoids significantly affected the total amount of extracted DNA, neither size nor DNA concentration were significant factors for the amplification of either gene region. We also tested several primer combinations of various lengths, but were unable to amplify fragments longer than ~150 base pairs. These short fragments of 28S and COI were however sufficient for species identification, and for the discovery of within species genetic variation

    An efficient prebreathing apparatus for humans during decompression

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    Portable prebreathing system was developed which recirculates and reconditions respiratorily exhaled oxygen. Apparatus reduces fire hazards, simplifies prebreathing procedures, and does not require extensive enclosure venting system usage

    Microbiological surface sampling cart

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    Mobile sampling cart automatically swabs surfaces for the recovery of microorganisms. Unit operates without human involvement and provides for control of swabbing speed, rotation of cotton swab, and the pressure and angle applied to swab. Capability of reverse direction is also available. Sampling cart use is limited to flat surfaces

    Automated single-slide staining device

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    A simple apparatus and method is disclosed for making individual single Gram stains on bacteria inoculated slides to assist in classifying bacteria in the laboratory as Gram-positive or Gram-negative. The apparatus involves positioning a single inoculated slide in a stationary position and thereafter automatically and sequentially flooding the slide with increments of a primary stain, a mordant, a decolorizer, a counterstain and a wash solution in a sequential manner without the individual lab technician touching the slide and with minimum danger of contamination thereof from other slides

    How has the Louisiana Scholarship Program Affected students? A Comprehensive Summary of Effects After Three Years

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    School choice reforms comprise a broad category of policies aimed at improving public education through the introduction of market forces that expand customer choice and competition between schools. Here we summarize our research to date on the effects of a large statewide school voucher initiative, the Louisiana Scholarship Program (LSP), and draw the following conclusions: • Overall, participating in the LSP had no statistically significant impact on student English Language Arts (ELA) or math scores after using an LSP scholarship for three years. • The subgroup of students who were lower achieving before applying to the program did show significant gains in ELA after three years of scholarship usage. Students applying to lower grades demonstrated significant losses in math. • Students without disabilities were less likely to be identified to receive special education services if they participated in the LSP than if they did not. Students with disabilities were more likely to be de-identified as requiring special education services if they participated in the private school choice program. • The private schools that chose to participate in the LSP were disproportionately Catholic, had low tuitions, had low enrollments, and served a high percentage of minority students. We discuss these findings in the remainder of this brief and in greater detail in the three accompanying technical reports. Combined with prior evidence, these results are informative about the specific design of voucher and other choice policies and about how the effects of choice evolve over time as programs mature

    A critical analysis of the hydrino model

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    Recently, spectroscopic and calorimetric observations of hydrogen plasmas and chemical reactions with them have been interpreted as evidence for the existence of electronic states of the hydrogen atom with a binding energy of more than 13.6 eV. The theoretical basis for such states, that have been dubbed hydrinos, is investigated. We discuss both, the novel deterministic model of the hydrogen atom, in which the existence of hydrinos was predicted, and standard quantum mechanics. Severe inconsistencies in the deterministic model are pointed out and the incompatibility of hydrino states with quantum mechanics is reviewed.Comment: 9 page

    The Effects of the Louisiana Scholarship Program on Student Achievement After Two Years

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    The Louisiana Scholarship Program (LSP) is a statewide initiative offering publicly-funded vouchers to enroll in local private schools to students in low-performing schools with family income no greater than 250 percent of the poverty line. Initially established in 2008 as a pilot program in New Orleans, the LSP was expanded statewide in 2012. This paper examines the experimental effects of using an LSP scholarship to enroll in a private school on student achievement in the first two years following the program’s expansion. Our results indicate that the use of an LSP scholarship has negatively impacted both ELA and math achievement, although only the latter estimates are statistically significant. Moreover, we observe less negative effect estimates in the second year of the program

    Automated single-slide staining system

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    Apparatus developed to Gram-stain single slides automatically is flexible enough to accommodate other types of staining procedures. Method frees operator and eliminates necessity for subjective evaluations as to length of staining or decolorizing time

    Apparatus for microbiological sampling

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    An automatic apparatus is described for microbiologically sampling surface using a cotton swab which eliminates human error. The apparatus includes a self-powered transport device, such as a motor-driven wheeled cart, which mounts a swabbing motor drive for a crank arm which supports a swab in the free end thereof. The swabbing motor is pivotably mounted and an actuator rod movable responsive to the cart traveling a predetermined distance provides lifting of the swab from the surface being sampled and reversal of the direction of travel of the cart
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