483 research outputs found
Rejuvenating Green OA for a Greener Pasture
This paper is a critical sequel to John Dove’s paper titled “Maximum Dissemination: A possible model for society journals in the humanities and social sciences to support Open while retaining their subscription revenue”, presented at the Charleston Conference 2019. Dove’s OA advocacy has included both gold and green. Dove’s innovative model, which makes full use of the green route to achieve maximum dissemination of authors’ works through open repositories, suggests a switch in the functional responsibility for depositing author’s manuscript from author to publisher. The model has publishers to act as agents of the authors as much through the green route as their subscription route. Dove has suggested this maximum use of the green path by the publisher for specific journals in specific disciplines. This paper looks to examine the feasibility of green OA model in this context, and then to consider other ways to expand on this idea to other green OA supporting publishers. It further looks at the possibilities of the model driving the re-emergence of green OA as a favoured option for facilitating immediate and parallel dissemination of authors’ papers through both green and subscription channels
GMOSS: All-sky model of spectral radio brightness based on physical components and associated radiative processes
We present Global MOdel for the radio Sky Spectrum (GMOSS) -- a novel,
physically motivated model of the low-frequency radio sky from 22 MHz to 23
GHz. GMOSS invokes different physical components and associated radiative
processes to describe the sky spectrum over 3072 pixels of
resolution. The spectra are allowed to be convex, concave or of more complex
form with contributions from synchrotron emission, thermal emission and
free-free absorption included. Physical parameters that describe the model are
optimized to best fit four all-sky maps at 150 MHz, 408 MHz, 1420 MHz and 23
GHz and two maps at 22 MHz and 45 MHz generated using the Global Sky Model of
de Oliveira-Costa et al. (2008). The fractional deviation of model to data has
a median value of and is less than for of the pixels.
Though aimed at modeling of foregrounds for the global signal arising from the
redshifted 21-cm line of Hydrogen during Cosmic Dawn and Epoch of Reionization
(EoR) - over redshifts , GMOSS is well suited for any
application that requires simulating spectra of the low-frequency radio sky as
would be observed by the beam of any instrument. The complexity in spectral
structure that naturally arises from the underlying physics of the model
provides a useful expectation for departures from smoothness in EoR foreground
spectra and hence may guide the development of algorithms for EoR signal
detection. This aspect is further explored in a subsequent paper.Comment: 19 pages, 7 figure
On the detection of spectral ripples from the Recombination Epoch
Photons emitted during the epochs of Hydrogen () and Helium recombination ( for HeII
HeI, for HeIII
HeII) are predicted to appear as broad, weak spectral distortions of the Cosmic
Microwave Background. We present a feasibility study for a ground-based
experimental detection of these recombination lines, which would provide an
observational constraint on the thermal ionization history of the Universe,
uniquely probing astrophysical cosmology beyond the last scattering surface. We
find that an octave band in the 2--6 GHz window is optimal for such an
experiment, both maximizing signal-to-noise ratio and including sufficient line
spectral structure. At these frequencies the predicted signal appears as an
additive quasi-sinusoidal component with amplitude about nK that is
embedded in a sky spectrum some nine orders of magnitude brighter. We discuss
an algorithm to detect these tiny spectral fluctuations in the sky spectrum by
foreground modeling. We introduce a \textit{Maximally Smooth} function capable
of describing the foreground spectrum and distinguishing the signal of
interest. With Bayesian statistical tests and mock data we estimate that a
detection of the predicted distortions is possible with 90\% confidence by
observing for 255 days with an array of 128 radiometers using cryogenically
cooled state-of-the-art receivers. We conclude that detection is in principle
feasible in realistic observing times; we propose APSERa---Array of Precision
Spectrometers for the Epoch of Recombination---a dedicated radio telescope to
detect these recombination lines.Comment: 33 pages, 16 figures, submitted to ApJ, comments welcom
ANTIOXIDANT AND HEPATO PROTECTIVE ACTIVITY OF VARIOUS EXTRACTS OF INDIGOFERA BARBERI GAMBLE AGAINST D-GALACTOSAMINE INDUCED TOXICITY IN RATS
Objective: To investigate Antioxidant and Hepatoprotective activity of various extracts of Indigofera barberi Gamble against D-Galactosamine induced toxicity in rats.
Methods: Indigofera barberi Gamble is used traditionally as folk system of medicine in India for the treatment of liver diseases, and as a liver tonic. Petroleum ether (PEEIB), chloroform(CEIB) and ethanolic extracts (EEIB) of Indigofera barberi Gamble (aerial part of the plants extracts, 200mg/kg, p. o) was tested for its hepatoprotective effect against D-galactosamine induced hepatic damage in rats at a dose of (400mg/kg, i. p) to induce hepatotoxicity and Silymarin (25 mg/kg, i. p.) was administered as standard drug.
Results: The biochemical parameters of liver tissue LPO, GSH, GPX, GST, SOD and CAT values were significantly (p<0.01) altered against ethanolic extracts treatment of Indigofera barberi Gamble and were comparable with standard drug silymarin.
Conclusion: Animal pretreatment with petroleum ether and chloroform extracts of Indigofera barberi Gamble did not change above mentioned parameters significantly. The histopathological studies also substantiates the results and hence, it can be concluded from the present study that, the ethanolic extracts of Indigofera barberi Gamble has appreciable hepatoprotective potential in albino rats against D-galactosamine induced hepatic damage
Somatic embryogenesis in Mucuna pruriens
This study reports the induction of somatic embryos in Mucuna pruriens. Different explants cultured on MS medium supplemented with 11.31 ìM 2,4-D produced golden yellow embryogenic callus that induced synchronized embryo development on MS basal liquid medium. Organization of pre-embryonic mass was noticed 15 d after sub culturing the callus, which progressively developed to globular, heart, torpedo and cotyledonary shaped embryos. Attempts to germinate them did not succeed as the cotyledonary embryos turned characteristic red and subsequently brown before finally turning blackand unresponsive. The reaction was consistent across different media constituents, hormonal concentrations and pH ranges. Supplementation of anti-oxidants was also ineffective. Polyacrylamide gel electrophoretic analysis of the brown and non-brown embryos revealed quantitative differences inprotein contents between the two. More detailed study is necessary to establish the precise cause for embryo browning and ways of its regulation
Effect of Bevel Angle in Bevel Groove Butt Joints on Shrinkages in CO2 Arc Welding Process
The in-plane distortions such as transverse shrinkages and longitudinal shrinkages induce residual stress in the welded joints which is undesirable as it reduces the strength of the welded structure. The problems of distortions in welded joints are of major concern in structures and the shipbuilding industry and in other similar manufacturing industries. The predictions of the degree of shrinkages in ship panels due to welding are of great importance from the point of view of dimensional control and it is important to analyze transverse shrinkages and longitudinal shrinkages. In this investigation, the experimental analysis of transverse shrinkages and longitudinal shrinkages bevel-groove butt welded joints in CO2 Arc Welding process by bevel angle and keeping process parameters constant. It was found that, the transverse and longitudinal shrinkages increase with increase in the bevel angle. There is a significant increase in the transverse shrinkage and small variation in longitudinal shrinkage
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