14,977 research outputs found
Noise characteristics of upper surface blown configurations: Analytical Studies
Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer
Carrier induced ferromagnetism in concentrated and diluted local-moment systems
For modeling the magnetic properties of concentrated and diluted magnetic
semiconductors, we use the Kondo-lattice model. The magnetic phase diagram is
derived by inspecting the static susceptibility of itinerant band electrons,
which are exchange coupled to localized magnetic moments. It turns out that
rather low band occupations favour a ferromagnetic ordering of the local moment
systems due to an indirect coupling mediated by a spin polarization of the
itinerant charge carriers. The disorder in diluted systems is treated by adding
a CPA-type concept to the theory. For almost all moment concentrations x,
ferromagnetism is possible, however, only for carrier concentrations n
distinctly smaller than x. The charge carrier compensation in real magnetic
semiconductors (in Ga_{1-x}Mn_{x}As by e.g. antisites) seems to be a necessary
condition for getting carrier induced ferromagnetism.Comment: 9 pages (REVTeX), 6 figures, to be published in Phys. Rev.
Effect of Organic Nutrition Practices on Papaya (cv. Surya) Fruit Yield, Quality and Soil Health
A field experiment was conducted during 2005-07 at Indian Institute of Horticultural Research, Bangalore, on papaya cv. Surya with six organic treatments along with recommended dose of fertilizers and no manure/fertilizer application. Results indicated that crop growth and fruit yield were higher in inorganic fertilizer treatment (55 t ha1) compared to organic treatments (26.9 to 38 t ha-1). There was no significant variation in average fruit weight and TSS, but shelf life of the fruit was significantly higher in organic treatments (6.2 to 7.9 days) as compared to inorganic fertilizer treatment (5.1days). Among the treatments, application of 7 kg urban compost plant-1 or 10 kg FYM plant-1 was found to be ideal for improving soil health in terms of microbial population, and biochemical reaction compared to other treatments
Many-Body Corrections to Charged-Current Neutrino Absorption Rates in Nuclear Matter
Including nucleon--nucleon correlations due to both Fermi statistics and
nuclear forces, we have developed a general formalism for calculating the
charged--current neutrino--nucleon absorption rates in nuclear matter. We find
that at one half nuclear density many--body effects alone suppress the rates by
a factor of two and that the suppression factors increase to 5 at
g cm. The associated increase in the neutrino--matter
mean--free--paths parallels that found for neutral--current interactions and
opens up interesting possibilities in the context of the delayed supernova
mechanism and protoneutron star cooling.Comment: 11 pages, APS REVTeX format, 1 PostScript figure, uuencoded
compressed, and tarred, submitted to Physical Review Letter
Fetal malnutrition and adult chronic disease
Since the fetal origins of adult disease hypothesis was put forward, more than 30 studies around the world have indicated low-birth-weight (LBW) infants have a higher incidence of hypertension and impaired glucose tolerance. India ranks second in incidence of LBW among South East Asian countries and is experiencing a transition of disease pattern from communicable disease to non-communicable disease. Whether this could be explained in part by LBW infants who experienced better nutrition at a later age is explored here. An earlier cohort with accurate birth weights was traced and enrolled into the study. A sample of 50 LBW and 78 normal birth weight (NBW) individuals are reported on here. Though the odds ratio (OR) estimates of risk factors for coronary heart disease and diabetes tended to be higher in LBWs who were better nourished at the time of the study, they were not statistically different. Similarly, OR estimates for risk factors tended to be higher in LBWs who put on more weight than the median of NBWs, but they were not significant. Logistic regressions with several variables indicated significant influence of body mass index on systolic (P<0.007) and diastolic (P<0.004) blood pressures. Since the risk associations are weak, more studies are needed to put the hypothesis on a firm footing
Surface PM machine parameter selection for wide field-weakening applications
Recent work on fractional-slot pitch, concentrated winding (FSCW) surface PM machines has shown that these machines can achieve a wide constant-power speed range. This paper shows that defining the allowable machine design parameter plane using the characteristic current and the peak back-emf provides useful insights into how application requirements restrict the machine parameters. The parameter plane also shows the influence of changing the parameters on the machine's current rating and magnet losses. As an example of a practical application, the parameter plane is used to study the FreedomCAR traction motor drive requirements and the characteristics of five FSCW surface PM machine designs.W.L. Soong, P.B. Reddy, A.M. El-Refaie, T.M. Jahns and N. Ertugru
Dust extinction from Balmer decrements of star-forming galaxies at 0.75<z<1.5 with HST/WFC3 spectroscopy from the WISP survey
Spectroscopic observations of Halpha and Hbeta emission lines of 128
star-forming galaxies in the redshift range 0.75<z<1.5 are presented. These
data were taken with slitless spectroscopy using the G102 and G141 grisms of
the Wide-Field-Camera 3 (WFC3) on board the Hubble Space Telescope as part of
the WFC3 Infrared Spectroscopic Parallel (WISP) survey. Interstellar dust
extinction is measured from stacked spectra that cover the Balmer decrement
(Halpha/Hbeta). We present dust extinction as a function of Halpha luminosity
(down to 3 x 10^{41} erg/s), galaxy stellar mass (reaching 4 x 10^{8} Msun),
and rest-frame Halpha equivalent width. The faintest galaxies are two times
fainter in Halpha luminosity than galaxies previously studied at z~1.5. An
evolution is observed where galaxies of the same Halpha luminosity have lower
extinction at higher redshifts, whereas no evolution is found within our error
bars with stellar mass. The lower Halpha luminosity galaxies in our sample are
found to be consistent with no dust extinction. We find an anti-correlation of
the [OIII]5007/Halpha flux ratio as a function of luminosity where galaxies
with L_{Halpha}<5 x 10^{41} erg/s are brighter in [OIII]5007 than Halpha. This
trend is evident even after extinction correction, suggesting that the
increased [OIII]5007/Halpha ratio in low luminosity galaxies is likely due to
lower metallicity and/or higher ionization parameters.Comment: 11 pages, 9 figures, 2 tables; version addressing the referee
comment
A to G transitions at 260, 386 and 437 in DAZL gene are not associated with spermatogenic failure in Indian population
The autosomal DAZL (Deleted-in-Azoospermic-Like) gene, mapped to the short arm of the human chromosome 3, is the precursor for the Y-chromosomal DAZ cluster, which encodes for putative RNA-binding proteins. Mutations in the DAZL have been reported to be associated with spermatogenic failure in Taiwanese population but not in Caucasians. As there was no study on Indian populations, we have analysed the entire coding sequences of exons 2 and 3 of DAZL in a total of 1010 men from Indian subcontinent, including 660 infertile men with 598 non-obstructive azoospermia, 62 severe oligozoospermia and 350 normozoospermic fertile control men, to investigate whether mutation(s) in the DAZL is associated with male infertility. Interestingly, none of our samples (1010) showed A386G (T54A) mutation, which was found to be associated with spermatogenic failure in Taiwanese population. In contrast, A260G (T12A) mutation was observed in both infertile and normozoospermic fertile control men, without any significant association with infertile groups (χ2=0.342; p=0.556). Similarly, we have found a novel A437G (I71V) mutation, which is also present in both infertile and normozoospermic fertile control men without any significant difference (χ2=0.476; p=0.490). Our study clearly demonstrates the complete absence of the A386G (T54A) mutation in Indian subcontinent and the other two mutations- A260G (T12A) and A437G (I71V)- observed are polymorpic. Therefore, we conclude that these mutations in the DAZL gene are not associated with male infertility in Indian subcontinent
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