21,086 research outputs found
Kinetics of the reduction of metalloproteins by chromous ion
The reduction of Cu(330) in Rhus vernicifera laccase by chromous ion is 30% faster than reduction of Cu(614) at room temperature [pH 4.8, µ = 0.1 (NaCl)], and two parallel first-order paths, attributed to heterogeneity of the protein, are observed at both wavelengths. The reactions of stellacyanin, spinach and French-bean plastocyanins, and cytochrome c with chromous ion under similar conditions are faster than that with laccase by factors of 102 to 104, and are first order in protein concentration. Comparison of rates and activation parameters for the reduction of "blue" copper in laccase, stellacyanin, and the two plastocyanins indicates that reduction of the Cu(614) site in laccase may occur by intramolecular electron transfer from one of the Cu(330) sites. Our value of ΔH (17.4 kcal/mol) for the chromous ion reduction of cytochrome c is consistent with a mechanism in which major conformational changes in the protein must accompany electron transfer
Discovery of the supernova remnant G351.0-5.4
Context. While searching the NRAO VLA Sky Survey (NVSS) for diffuse radio
emission, we have serendipitously discovered extended radio emission close to
the Galactic plane. The radio morphology suggests the presence of a previously
unknown Galactic supernova remnant. An unclassified {\gamma}-ray source
detected by EGRET (3EG J1744-3934) is present in the same location and may stem
from the interaction between high-speed particles escaping the remnant and the
surrounding interstellar medium.
Aims. Our aim is to confirm the presence of a previously unknown supernova
remnant and to determine a possible association with the {\gamma}-ray emission
3EG J1744-3934.
Methods. We have conducted optical and radio follow-ups of the target using
the Dark Energy Camera (DECam) on the Blanco telescope at Cerro Tololo
Inter-American Observatory (CTIO) and the Giant Meterwave Radio Telescope
(GMRT). We then combined these data with archival radio and {\gamma}-ray
observations.
Results. While we detected the extended emission in four different radio
bands (325, 1400, 2417, and 4850 MHz), no optical counterpart has been
identified. Given its morphology and brightness, it is likely that the radio
emission is caused by an old supernova remnant no longer visible in the optical
band. Although an unclassified EGRET source is co-located with the supernova
remnant, Fermi-LAT data do not show a significant {\gamma}-ray excess that is
correlated with the radio emission. However, in the radial distribution of the
{\gamma}-ray events, a spatially extended feature is related with SNR at a
confidence level {\sigma}.
Conclusions. We classify the newly discovered extended emission in the radio
band as the old remnant of a previously unknown Galactic supernova: SNR
G351.0-5.4.Comment: 6 pages, 6 figures, accepted A&
Induced Second Trimester Abortion and Associated Factors at Debre Markos Referral Hospital: Cross-Sectional Study.
BACKGROUND:Although most induced abortions in Ethiopia are performed in the first trimester, many women will still require second trimester abortions. While access to abortion in Ethiopia is limited, few data are being available concerning the demand for and associated outcomes of second trimester abortions. This knowledge is important for planning the health service response to abortion. OBJECTIVE:The main objective of this study was to determine the proportion and associated factors of second trimester abortion among women presenting for abortion care services at Debre Markos Referral Hospital, Debre Markos, Northwest Ethiopia. METHODS:An institution-based cross-sectional study was conducted at Debre Markos Referral Hospital on a sample of 262 calculated using the single population proportion formula. Women who sought abortion services were interviewed consecutively from 12 February 2017 to 14 March 2017. Data were collected in a face-to-face exit interview and document review and analyzed using SPSS version 24.0 software. Bivariate and multivariable analyses were undertaken to identify factors. RESULT:Of the women who presented for abortion care services in Debre Markos Referral Hospital, 73 (29.6%) had induced second trimester abortion. Unmarried women (adjusted odds ratio = 4.93, 95% confidence interval = 1.41-17.16) and women employed at private business (adjusted odds ratio = 6.17, 95% confidence interval = 1.16-32.76) were associated with induced second trimester abortion. CONCLUSION:This study revealed that almost one-third of women who presented for abortion care services at Debre Markos Referral Hospital had induced second trimester abortions. Raising awareness of the health consequence of second trimester abortion at community levels and counseling to avoid further occurrences are helpful to minimize the problem. Furthermore, early management of induced second trimester abortion is very crucial to prevent further complications
Study and applications of retrodirective and self adaptive electromagnetic-wave phase controls to a Mars probe
Computer analyses of retrodirective, and self adaptive antenna phase control techniques for Mars prob
Evidence for quantum confinement in the photoluminescence of porous Si and SiGe
We have used anodization techniques to process porous surface regions in p-type Czochralski Si and in p-type Si0.85Ge0.15 epitaxial layers grown by molecular beam epitaxy. The SiGe layers were unrelaxed before processing. We have observed strong near-infrared and visible light emission from both systems. Analysis of the radiative and nonradiative recombination processes indicate that the emission is consistent with the decay of excitons localized in structures of one or zero dimensions
Simulation Study of TenTen: A new Multi-TeV IACT array
TenTen is a proposed array of Imaging Atmospheric Cherenkov Telescopes (IACT)
optimized for the gamma ray energy regime of 10 TeV to 100 TeV, but with a
threshold of ~1 to a few TeV. It will offer a collecting area of 10 km2 above
energies of 10 TeV. In the initial phase, a cell of 3 to 5 modest-sized
telescopes, each with 10-30 m2 mirror area, is suggested for an Australian
site. A possible expansion of the array could comprise many such cells. Here we
present work on configuration and technical issues from our simulation studies
of the array. Working topics include array layout, telescope size and optics,
camera field of view, telescope trigger system, electronics, and site surveys.Comment: 4 pages, 7 figures, submitted to Proceedings of the ICRC 2007, pdf
forma
Investigating Nabisco\u27s claim that double stuf Oreos contain double the stuff
The objective of this study was to test Nabisco\u27s claim that Double Stuf Oreos contain double the \stuf\ when compared to original Oreos. Six packages of each type of cookie were purchased from 3 local grocery stores. For each package 10 cookies were randomly selected using a random number generator. Sixty of each cookie type was used in this study. Total cookie weight of each cookie side and cream weight were measured in grams for each cookie. Results from a t-test indicate no evidence that consumers are getting less than double the stuff and a 95% confidence interval constructed for the ratio of means also supports this
TenTen: A New Array of Multi-TeV Imaging Cherenkov Telescopes
The exciting results from H.E.S.S. point to a new population of gamma-ray
sources at energies E > 10 TeV, paving the way for future studies and new
discoveries in the multi-TeV energy range. Connected with these energies is the
search for sources of PeV cosmic-rays (CRs) and the study of multi-TeV
gamma-ray production in a growing number of astrophysical environments. TenTen
is a proposed stereoscopic array (with a suggested site in Australia) of
modest-sized (10 to 30m^2) Cherenkov imaging telescopes with a wide field of
view (8 to 10deg diameter) optimised for the E~10 to 100 TeV range. TenTen will
achieve an effective area of ~10 km^2 at energies above 10 TeV. We outline here
the motivation for TenTen and summarise key performance parameters.Comment: 4 pages, 2 figures, proceedings of the 30th ICRC, Merida, Mexico,
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The reproducibility of physiological responses and performance profiles of youth soccer players in small-sided games
Place-based marketing and wine tourism: creating a point of difference and economic sustainability for small wineries
The purpose of this paper is to explore how small-scale wineries and wine regions create a point of difference and economic sustainability in a competitive marketplace through utilizing regional place branding and cellar door visitation. This research is based on qualitative, semi-structured, in-depth interviews with winery owners/managers and additional wine and tourism stakeholders in a single case study: The Central Otago wine region in the South Island of New Zealand. In total, 39 interviews were conducted in 2007 and 2010. Interviews were audio-recorded, transcribed verbatim, coded and categorized for analysis. Place marketing is a significant factor in the success of both regional and individual wine marketing initiatives, as it serves as a strategy of differentiation. Desirable regional attributes, as well as emotionally-appealing stories of the people and processes behind wine production, have been used deliberately by respondents in the marketing of Central Otago wine products and experiences. Respondents suggest that one of the most effective ways to facilitate a positive association between place and their product in the minds of consumers is through winery visitation, whereby visitors come to associate the region’s wines with the landscape and beauty of the area that they experience. Visitors also have the opportunity to experience the stories behind the wine, building emotional connections with the winery, and the region, which may ultimately lead to brand loyalty
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