1,138 research outputs found
Variable geometry inlet design for scram jet engine
The present invention relates to an improved variable geometry inlet for a scram jet engine having at least one combustor module. The variable geometry inlet comprises each combustor module having two sidewalls. Each of the sidewalls has a central portion with a thickness and a tapered profile forward of the central portion. The tapered profile terminates in a sharp leading edge. The variable geometry inlet further comprises each module having a lower wall and a movable cowl flap positioned forward of the lower wall. The movable cowl flap has a leading edge and the leading edges of the sidewalls intersect the leading edge of the cowl flap
Critical Analysis of Theoretical Estimates for to Light Meson Form Factors and the Data
We point out that current estimates of form factors fail to explain the
non-leptonic decays and that the combination of data
on the semi-leptonic decays and on the non-leptonic
decays (in particular recent po\-la\-ri\-za\-tion
data) severely constrain the form (normalization and dependence) of the
heavy-to-light meson form factors, if we assume the factorization hypothesis
for the latter. From a simultaneous fit to \bpsi and \dk data we find that
strict heavy quark limit scaling laws do not hold when going from to
and must have large corrections that make softer the dependence on the masses.
We find that should increase slower with \qq than .
We propose a simple parametrization of these corrections based on a quark
model or on an extension of the \hhs laws to the \hl case, complemented with an
approximately constant . We analyze in the light of these data and
theoretical input various theoretical approaches (lattice calculations, QCD sum
rules, quark models) and point out the origin of the difficulties encountered
by most of these schemes. In particular we check the compatibility of several
quark models with the heavy quark scaling relations.Comment: 48 pages, DAPNIA/SPP/94-24, LPTHE-Orsay 94/1
Comparative exergy analysis of direct alcohol fuel cells using fuel mixtures
Within the last years there has been increasing interest in direct liquid fuel cells as power sources for portable devices and, in the future, power plants for electric vehicles and other transport media as ships will join those applications. Methanol is considerably more convenient and easy to use than gaseous hydrogen and a considerable work is devoted to the development of direct methanol fuel cells. But ethanol has much lower toxicity and from an ecological viewpoint ethanol is exceptional among all other types of fuel as is the only chemical fuel in renewable supply. The aim of this study is to investigate the possibility of using direct alcohol fuel cells fed with alcohol mixtures. For this purpose, a comparative exergy analysis of a direct alcohol fuel cell fed with alcohol mixtures against the same fuel cell fed with single alcohols is performed. The exergetic efficiency and the exergy loss and destruction are calculated and compared in each case. When alcohol mixtures are fed to the fuel cell, the contribution of each fuel
to the fuel cell performance is weighted attending to their relative proportion in the aqueous solution. The optimum alcohol composition for methanol/ethanol mixtures has been determined
HUBUNGAN PENINGKATAN BERAT BADAN FE4NGAN KONVERSI SPUTUM PADA PASIEN TUBERKULOSIS DI RSUDZA BANDA ACEH
ABSTRAKKonversi sputum pada fase awal pengobatan merupakan salah satu indikator awal keberhasilan terapi obat anti tuberkulosis (OAT). Nutrisi merupakan faktor penting yang juga mempengaruhi kesembuhan pasien tuberkulosis Penelitian ini bertujuan untuk mengetahui hubungan peningkatan berat badan dengan konversi sputum setelah fase awal pada pasien TB di Rumah Sakit Umum dr. Zainoel Abidin Banda Aceh (RSUDZA). Jenis penelitian yang digunakan adalah Cross sectional. Subjek penelitian terdiri atas 92 pasien tuberkulosis di poliklinik DOTS RSUDZA Banda Aceh yang diperoleh dengan metode total sampling terhitung dari Januari sampai dengan Desember 2013. Hasil penelitian dianalisis menggunakan uji statistik Fisher dengan Confident interval 95%. Hasil uji statistik menunjukkan p = 0,107 (p > 0,05) yang menunjukkan bahwa tidak ada hubungan antara peningkatan berat badan dengan konversi sputum pada penderita tuberkulosis yang telah mendapatkan OAT fase awal. Diharapkan adanya penelitian yang lebih lanjut mengenai hubungan nutrisi dengan konversi sputum dengan jumlah sampel yang lebih besar dan desain penelitian yang lebih baik. Kata Kunci : Tuberkulosis, Konversi sputum, Berat badan ABSTRACTSputum conversion at the initial phase of treatment is one of the early indicators of the success of anti-tuberculosis drug therapy (OAT). Nutrition is an important factor that also effects the recovery of tuberculosis patients The aim of this study was to determine the relationship of weight gain and sputum conversion after the initial phase of TB patients at the General Hospital dr. Zainoel Abidin Banda Aceh (RSUDZA). This research was cross sectional study. Subjects consisted of 92 outpatient DOTS tuberculosis in RSUDZA Banda Aceh obtained with total sampling method starting from January to December 2013. Results were analyzed using Fisher test with 95% confident interval. Statistical test results p= 0,107 (p > 0,05) that showed there is no association between increased weight to conversion of sputum in patients with tuberculosis who have earned OAT initial phase, It is expected that the presence of further reaserh on the relationship of nutrition with sputum convertion with a larger number of sampel and design better research. Keywords: Tuberculosis, Sputum conversion, Weight los
Under-representation of Hispanics in Gifted Education : A Look across State Lines
This paper is the first to test a national panel data set of Hispanic enrollments in gifted education. Using data from 2002-2010, it is found that lower education budgets have a disproportionately negative impact on Hispanics and differences across states in learning disability programs may lower Hispanic gifted enrollments. Larger Hispanic student populations do not seem to be a significant factor across states, but have a negative effect within states over time. Graduating a high percentage of Hispanic students increases gifted program enrollments. Identification of students as learning disabled needs to be reexamined in the context of race/ethnicity as well. JEL Classification: I21, I2
Nucleon to Delta Weak Excitation Amplitudes in the Non-relativistic Quark Model
We investigate the nucleon to Delta(1232) vector and axial vector amplitudes
in the non-relativistic quark model of the Isgur-Karl variety. A particular
interest is to investigate the SU(6) symmetry breaking, due to color hyperfine
interaction. We compare the theoretical estimates to recent experimental
investigation of the Adler amplitudes by neutrino scattering.Comment: \documentstyle[aps]{revtex}, 21pages; 11 postscript figures. Accepted
for publication by Phys. Rev.
Verified and potential pathogens of predatory mites (Acari: Phytoseiidae)
Several species of phytoseiid mites (Acari: Phytoseiidae), including species of the genera Amblyseius, Galendromus, Metaseiulus, Neoseiulus, Phytoseiulus and Typhlodromus, are currently reared for biological control of various crop pests and/or as model organisms for the study of predator¿prey interactions. Pathogen-free phytoseiid mites are important to obtain high efficacy in biological pest control and to get reliable data in mite research, as pathogens may affect the performance of their host or alter their reproduction and behaviour. Potential and verified pathogens have been reported for phytoseiid mites during the past 25 years. The present review provides an overview, including potential pathogens with unknown host effects (17 reports), endosymbiotic Wolbachia (seven reports), other bacteria (including Cardinium and Spiroplasma) (four reports), cases of unidentified diseases (three reports) and cases of verified pathogens (six reports). From the latter group four reports refer to Microsporidia, one to a fungus and one to a bacterium. Only five entities have been studied in detail, including Wolbachia infecting seven predatory mite species, other endosymbiotic bacteria infecting Metaseiulus (Galendromus, Typhlodromus) occidentalis (Nesbitt), the bacterium Acaricomes phytoseiuli infecting Phytoseiulus persimilis Athias-Henriot, the microsporidium Microsporidium phytoseiuli infecting P. persimilis and the microsporidium Oligosproridium occidentalis infecting M. occidentalis. In four cases (Wolbachia, A. phytoseiuli, M. phytoseiuli and O. occidentalis) an infection may be connected with fitness costs of the host. Moreover, infection is not always readily visible as no obvious gross symptoms are present. Monitoring of these entities on a routine and continuous basis should therefore get more attention, especially in commercial mass-production. Special attention should be paid to field-collected mites before introduction into the laboratory or mass rearing, and to mites that are exchanged among rearing facilities. However, at present general pathogen monitoring is not yet practical as effects of many entities are unknown. More research effort is needed concerning verified and potential pathogens of commercially reared arthropods and those used as model organisms in research
Fitness-based Linkage Learning and Maximum-Clique Conditional Linkage Modelling for Gray-box Optimization with RV-GOMEA
For many real-world optimization problems it is possible to perform partial
evaluations, meaning that the impact of changing a few variables on a
solution's fitness can be computed very efficiently. It has been shown that
such partial evaluations can be excellently leveraged by the Real-Valued GOMEA
(RV-GOMEA) that uses a linkage model to capture dependencies between problem
variables. Recently, conditional linkage models were introduced for RV-GOMEA,
expanding its state-of-the-art performance even to problems with overlapping
dependencies. However, that work assumed that the dependency structure is known
a priori. Fitness-based linkage learning techniques have previously been used
to detect dependencies during optimization, but only for non-conditional
linkage models. In this work, we combine fitness-based linkage learning and
conditional linkage modelling in RV-GOMEA. In addition, we propose a new way to
model overlapping dependencies in conditional linkage models to maximize the
joint sampling of fully interdependent groups of variables. We compare the
resulting novel variant of RV-GOMEA to other variants of RV-GOMEA and VkD-CMA
on 12 problems with varying degree of overlapping dependencies. We find that
the new RV-GOMEA not only performs best on most problems, also the overhead of
learning the conditional linkage models during optimization is often
negligible
Distinct phenotypes of three-repeat and four-repeat human tau in a transgenic model of tauopathy.
Tau exists as six closely related protein isoforms in the adult human brain. These are generated from alternative splicing of a single mRNA transcript and they differ in the absence or presence of two N-terminal and three or four microtubule binding domains. Typically all six isoforms have been considered functionally similar. However, their differential involvement in particular tauopathies raises the possibility that there may be isoform-specific differences in physiological function and pathological role. To explore this, we have compared the phenotypes induced by the 0N3R and 0N4R isoforms in Drosophila. Expression of the 3R isoform causes more profound axonal transport defects and locomotor impairments, culminating in a shorter lifespan than the 4R isoform. In contrast, the 4R isoform leads to greater neurodegeneration and impairments in learning and memory. Furthermore, the phosphorylation patterns of the two isoforms are distinct, as is their ability to induce oxidative stress. These differences are not consequent to different expression levels and are suggestive of bona fide physiological differences in isoform biology and pathological potential. They may therefore explain isoform-specific mechanisms of tau-toxicity and the differential susceptibility of brain regions to different tauopathies
- …
