102 research outputs found
Adire in South-western Nigeria: Geography of the Centres
Adire, the patterned dyed cloth is extant and is practiced in almost all Yoruba towns in Southwestern Nigeria. The art tradition is however preponderant in a few Yoruba towns to the extent that the names of these towns are traditionally inseparable with the Adire art tradition. With Western education, introduction of foreign religions, influence from other cultures, technique and technology, there is a shift in the producers of Adire, the training pattern, and even an evolution in the production centre. While Western education resulted in a shift from the hitherto traditional apprenticeship method to the study of the art in schools, unemployment gave birth to the introduction of training drives by government and non governmental parastatals. This study, a field research, is an appraisal of the factors that contributed to the vibrancy of the traditionally renowned centres, and how the newly evolved centres have in contemporary times contributed to the sustainability of the Adire art tradition.Key words: Adire, Geography, Centre
Evolution and Final Fates of a Rotating 25 M Pop III star
In this proceeding, we present the 1-dimensional stellar evolution of two
rotating population III (Pop III) star models, each having a mass of 25
M at the zero-age main-sequence (ZAMS). The slowly rotating model has
an initial angular rotational velocity of 10 per cent of the critical angular
rotational velocity. In contrast, the rapidly rotating model has an initial
angular rotational velocity of 70 per cent of the critical angular rotational
velocity. As an effect of rotationally enhanced mixing, we find that the
rapidly rotating model suffers an enormous mass loss due to the deposition of a
significant amount of CNO elements toward the surface after the main-sequence
phase. We also display the simulated light curves as these models explode into
core-collapse supernovae (CCSNe).Comment: Resubmitted after incorporating minor revision, Part of 3 BINA
conference proceeding
Recent observations of peculiar Gamma-ray bursts using 3.6 m Devasthal Optical Telescope (DOT)
India has been actively involved in the follow-up observations of optical
afterglows of gamma-ray bursts (GRBs) for more than two decades, using the
country's meter-class facilities such as the 1.04 m Sampurnanand Telescope, 1.3
m Devasthal Fast Optical Telescope, 2.01 m Himalayan Chandra Telescope along
with many others in the country, utilizing the longitudinal advantage of the
place. However, since 2016, Indian astronomers have embarked on a new era of
exploration by utilizing the country's largest optical telescope, the 3.6 m
Devasthal Optical Telescope (DOT) at the Devasthal Observatory of ARIES
Nainital. This unique telescope has opened up exciting opportunities for
transient study. Starting from the installation itself, the DOT has been
actively performing the target of opportunity (ToO) observations, leading to
many interesting discoveries. Notable achievements include the contributions
towards the discovery of long GRB 211211A arising from a binary merger, the
discovery of the most delayed optical flare from GRB 210204A along with the
very faint optical afterglow (fainter than 25 mag in g-band) of GRB 200412B. We
also successfully observed the optical counterpart of the very-high-energy
(VHE) detected burst GRB 201015A using DOT. Additionally, DOT has been used for
follow-up observations of dark and orphan afterglows, along with the
observations of host galaxies associated with peculiar GRBs. More recently,
DOT's near-IR follow-up capabilities helped us to detect the first near-IR
counterpart (GRB 230409B) using an Indian telescope. In this work, we summarise
the recent discoveries and observations of GRBs using the 3.6 m DOT,
highlighting the significant contributions in revealing the mysteries of these
cosmic transients.Comment: 16 pages, 2 figures, 1 table, accepted for publication in the
Bulletin of Li\`ege Royal Society of Sciences as a part of 3
Belgo-Indian Network for Astronomy and Astrophysics (BINA) workshop, 22-24
March 202
Tale of GRB 171010A/SN 2017htp and GRB 171205A/SN 2017iuk: Magnetar origin?
We present late-time optical follow-up observations of GRB 171010A/SN 2017htp
( = 0.33) and low-luminosity GRB 171205A/SN 2017iuk ( = 0.037) acquired
using the 4K4K CCD Imager mounted at the 3.6m Devasthal Optical
Telescope (3.6m DOT) along with the prompt emission data analysis of these two
interesting bursts. The prompt characteristics (other than brightness) such as
spectral hardness, T, and minimum variability time-scale are comparable
for both the bursts. The isotropic -ray and kinetic energies of the plateau
phase of GRB 171205A are found to be less than the maximum energy budget of
magnetars, supporting magnetar as a central engine powering source. The new
optical data of SN 2017htp and SN 2017iuk presented here, along with published
ones, indicate that SN 2017htp is one of the brightest and SN 21017iuk is among
the faintest GRB associated SNe (GRB-SNe). Semi-analytical light-curve
modelling of SN 2017htp, SN 2017iuk and only known GRB associated superluminous
supernova (SLSN 2011kl) are performed using the code. The
model with a spin-down millisecond magnetar as a central engine powering source
nicely reproduced the bolometric light curves of all three GRB-SNe mentioned
above. The magnetar central engines for SN 2017htp, SN 2017iuk, and SLSN 2011kl
exhibit values of initial spin periods higher and magnetic fields closer to
those observed for long GRBs and H-deficient SLSNe. Detection of these rare
events at such late epochs also demonstrates the capabilities of the 3.6m DOT
for deep imaging considering longitudinal advantage in the era of time-domain
astronomy.Comment: Accepted for publication in New Astronomy; Received 21 April 2022,
Revised 13 June 2022, Accepted 1 July 202
Not Available
Not AvailableThe 'Farmer FIRST Programme’ was a unique initiative of Indian Council of Agricultural Research (ICAR) that
focussed on farmers’ Farm, Innovations, Resources, Science and Technology (FIRST) where farmers played
centric role for research problem identification, prioritization and conduct of experiments and its management
in field conditions. The major target groups were small and marginal farmers including women. The problems
of farmers related to agricultural production were discussed in details in farmer-scientist interface and those
problems were addressed with best suitable interventions covered under different modules. Organizing training
programmes/exposure visits for farmers to enrich technical knowledge; supplying superior quality germplasm
of various crops/livestock/poultry strains/fishes; using soil test-based fertilizers; managing nutrients through
leaf colour chart; practising line transplanting in paddy; using mulching for soil moisture conservation; using
poly house technology; adopting sprinkler/drip irrigation; using trellis system in horticultural crops production;
managing crops, livestock, poultry and fishes scientifically; selecting appropriate enterprises, establishing
marketing channels for agricultural produces were among the major interventions adopted under this programme. As a result, agricultural production was increased substantially under crop- and horticulture-based module
(both varied from 20-200%), natural resource management module (ranged between 12 and 100%), livestock
module (varied from 15-150%), enterprise-based module (ranged from 12-100%) and integrated farming
system-based module (ranged between 14 and 200%) which fetched higher income to the farmers than before
adopting interventions.Not Availabl
Green revolution in Sub-Saharan Africa: Implications of imposed innovation for the wellbeing of rural smallholders
Green Revolution policies are again being pursued to drive agricultural growth and reduce poverty in Sub-Saharan Africa. However conditions have changed since the well-documented successes of the 1960s and 1970s benefited smallholders in southern Asia and beyond. We argue that under contemporary constraints the mechanisms for achieving improvements in the lives of smallholder farmers through such policies are unclear and that both policy rationale and means of governing agricultural innovation are crucial for pro-poor impacts. To critically analyze Rwanda’s Green Revolution policies and impacts from a local perspective, a mixed methods, multidimensional wellbeing approach is applied in rural areas in mountainous western Rwanda. Here Malthusian policy framing has been used to justify imposed rather than ‘‘induced innovation”. The policies involve a substantial transformation for rural farmers from a traditional polyculture system supporting subsistence and local trade to the adoption of modern seed varieties, inputs, and credit in order to specialize in marketable crops and achieve increased production and income. Although policies have been deemed successful in raising yields and conventionally measured poverty rates have fallen over the same period, such trends were found to be quite incongruous with local experiences. Disaggregated results reveal that only a relatively wealthy minority were able to adhere to the enforced modernization and policies appear to be exacerbating landlessness and inequality for poorer rural inhabitants. Negative impacts were evident for the majority of households as subsistence practices were disrupted, poverty exacerbated, local systems of knowledge, trade, and labor were impaired, and land tenure security and autonomy were curtailed. In order to mitigate the effects we recommend that inventive pro-poor forms of tenure and cooperation (none of which preclude improvements to input availability, market linkages, and infrastructure) may provide positive outcomes for rural people, and importantly in Rwanda, for those who have become landless in recent years. We conclude that policies promoting a Green Revolution in Sub-Saharan Africa should not all be considered to be pro-poor or even to be of a similar type, but rather should be the subject of rigorous impact assessment. Such assessment should be based not only on consistent, objective indicators but pay attention to localized impacts on land tenure, agricultural practices, and the wellbeing of socially differentiated people
A LOFAR prompt search for radio emission accompanying X-ray flares in GRB 210112A
© The Author(s) 2023. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/).The composition of relativistic gamma-ray burst (GRB) jets and their emission mechanisms are still debated, and they could be matter or magnetically dominated. One way to distinguish these mechanisms arises because a Poynting flux dominated jet may produce low-frequency radio emission during the energetic prompt phase, through magnetic reconnection at the shock front. We present a search for radio emission coincident with three GRB X-ray flares with the LOw Frequency ARray (LOFAR), in a rapid response mode follow-up of long GRB 210112A (at z~2) with a 2 hour duration, where our observations began 511 seconds after the initial swift-BAT trigger. Using timesliced imaging at 120-168 MHz, we obtain upper limits at 3 sigma confidence of 42 mJy averaging over 320 second snapshot images, and 87 mJy averaging over 60 second snapshot images. LOFAR's fast response time means that all three potential radio counterparts to X-ray flares are observable after accounting for dispersion at the estimated source redshift. Furthermore, the radio pulse in the magnetic wind model was expected to be detectable at our observing frequency and flux density limits which allows us to disfavour a region of parameter space for this GRB. However, we note that stricter constraints on redshift and the fraction of energy in the magnetic field are required to further test jet characteristics across the GRB population.Peer reviewe
In vitro and in vivo single-agent efficacy of checkpoint kinase inhibition in acute lymphoblastic leukemia
Background: Although progress in children, in adults, ALL still carries a dismal outcome. Here, we explored the in vitro and in vivo activity of PF-00477736 (Pfizer), a potent, selective ATP-competitive small-molecule inhibitor of checkpoint kinase 1 (Chk1) and with lower efficacy of checkpoint kinase 2 (Chk2). Methods: The effectiveness of PF-00477736 as single agent in B-/T-ALL was evaluated in vitro and in vivo studies as a single agent. The efficacy of the compound in terms of cytotoxicity, induction of apoptosis, and changes in gene and protein expression was assessed using different B-/T-ALL cell lines. Finally, the action of PF-00477736 was assessed in vivo using leukemic mouse generated by a single administration of the tumorigenic agent n-ethyl-n-nitrosourea. Results: Chk1 and Chk2 are overexpressed concomitant with the presence of genetic damage as suggested by the nuclear labeling for \u3b3-H2A.X (Ser139) in 68 % of ALL patients. In human B-and T-ALL cell lines, inhibition of Chk1/2 as a single treatment strategy efficiently triggered the Chk1-Cdc25-Cdc2 pathway resulting in a dose-and time-dependent cytotoxicity, induction of apoptosis, and increased DNA damage. Moreover, treatment with PF-00477736 showed efficacy ex vivo in primary leukemic blasts separated from 14 adult ALL patients and in vivo in mice transplanted with T-ALL, arguing in favor of its future clinical evaluation in leukemia. Conclusions: In vitro, ex vivo, and in vivo results support the inhibition of Chk1 as a new therapeutic strategy in acute lymphoblastic leukemia, and they provide a strong rationale for its future clinical investigation
SN 2016iyc : a Type IIb supernova arising from a low-mass progenitor
In this work, photometric and spectroscopic analyses of a very low-luminosity Type IIb supernova (SN) 2016iyc have been performed. SN 2016iyc lies near the faint end among the distribution of similar supernovae (SNe). Given lower ejecta mass (Mej) and low nickel mass (MNi) from the literature, combined with SN 2016iyc lying near the faint end, one-dimensional stellar evolution models of 9–14 M⊙ zero-age main-sequence (ZAMS) stars as the possible progenitors of SN 2016iyc have been performed using the publicly available code mesa. Moreover, synthetic explosions of the progenitor models have been simulated, using the hydrodynamic evolution codes stella and snec. The bolometric luminosity light curve and photospheric velocities produced through synthetic explosions of ZAMS stars of mass in the range of 12–13 M⊙ having a pre-supernova radius R0 = (204–300) R⊙, with Mej = (1.89–1.93) M⊙, explosion energy Eexp = (0.28–0.35) × 1051 erg, and MNi < 0.09 M⊙, are in good agreement with observations; thus, SN 2016iyc probably exploded from a progenitor near the lower mass limits for SNe IIb. Finally, hydrodynamic simulations of the explosions of SN 2016gkg and SN 2011fu have also been performed to compare intermediate- and high-luminosity examples among well-studied SNe IIb. The results of progenitor modelling and synthetic explosions for SN 2016iyc, SN 2016gkg, and SN 2011fu exhibit a diverse range of mass for the possible progenitors of SNe IIb
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