745 research outputs found
Neutrino masses, cosmological bound and four zero Yukawa textures
Four zero neutrino Yukawa textures in a specified weak basis, combined with
symmetry and type-I seesaw, yield a highly constrained and predictive
scheme. Two alternately viable light neutrino Majorana mass matrices
result with inverted/normal mass ordering. Neutrino
masses, Majorana in character and predicted within definite ranges with
laboratory and cosmological inputs, will have their sum probed cosmologically.
The rate for decay, though generally below the reach of
planned experiments, could approach it in some parameter region. Departure from
symmetry due to RG evolution from a high scale and consequent CP
violation, with a Jarlskog invariant whose magnitude could almost reach
, are explored.Comment: Published versio
A simulation study of pearlite-to-austenite transformation kinetics in rapidly heated hot-rolled low carbon steel
The main aim of the present research was to obtain an optimized microstructure with adequate mechanical properties in a low carbon steel. The effect of microstructure on kinetics of austenite transformation was simulated. A 3.2 mm hot rolled steel was subjected to continuous annealing to obtain properties of Dual Phase 590 grade. Kinetics of austenite transformation was studied with respect to the condition of just pearlite dissolution to form austenite under rapid heating. Annealing parameters were based on process conditions of dual phase steel production in a continuous annealing line. DICTRA was used to simulate heating rates of the order 10–500 °C/s with peak temperatures in the range 750–850 °C to predict isothermal annealing time required for complete dissolution of pearlite into austenite under different temperature-heating rate conditions. Simulation results showed dependency of temperature and heating rate on austenite transformation time. Interestingly, no significant effect of heating rate on complete pearlite dissolution into austenite was evident. Results were validated with limited experimentation on Gleeble. Microstructure analysis validated the simulation results to be accurate. The observations have pertinent inputs while designing industrial continuous annealing line parameters where rapid heating rates are generally encountered (10–20 °C/s).A simulation study of pearlite-to-austenite transformation kinetics in rapidly heated hot-rolled low carbon steel (PDF Download Available). Availablefrom:https://www.researchgate.net/publication/303915593_A_simulation_study_of_pearlite-to austenite_transformation_kinetics_in_rapidly_heated_hot-rolled_low_carbon_steel [accessed Aug 14, 2017]
Baryon asymmetry from leptogenesis with four zero neutrino Yukawa textures
The generation of the right amount of baryon asymmetry of the Universe
from supersymmetric leptogenesis is studied within the type-I seesaw framework
with three heavy singlet Majorana neutrinos and their
superpartners. We assume the occurrence of four zeroes in the neutrino Yukawa
coupling matrix , taken to be symmetric, in the weak basis
where (with real masses ) and the charged leptons are mass diagonal. The quadrant of the single nontrivial
phase, allowed in the corresponding light neutrino mass matrix , gets
fixed and additional constraints ensue from the requirement of matching
with its observed value. Special attention is paid to flavor effects in the
washout of the lepton asymmetry. We also comment on the role of small
departures from high scale symmetry due to RG evolution.Comment: 35 pages, no figure, Published Versio
Impact of COVID-19 pandemic on safe abortion and family planning services at a tertiary care women’s hospital in Nepal
Background: The COVID-19pandemic emerged as a major public health crisis, which has affected all dimensions of the health care system. Sexual and reproductive health services were severely affected, leading to a decrease in access and service utilization, affecting the overall health of women.Methods: A two-year comparative study, before and during the COVID-19 pandemic, on safe abortion services and family planning, was conducted at Paropakar maternity and women's hospital to assess the impact of COVID-19 on service utilization.Results: Safe abortion services were decreased by 34.4%, and family planning services by 39%, in 2020 as compared to the previous year. Uptake of long-acting reversible contraceptives and permanent methods was most affected. Utilization of services was affected markedly during lockdown, and showed a persistent decline, even after the lockdown was lifted.Conclusions: The COVID-19 pandemic has seriously affected safe abortion and family planning services in Nepal due to lockdown, travel restriction, home isolation, resource reallocation, health facilities serving only emergencies and confusing messages about COVID-19 control. The decline in these services will create additional demand and pressure on the health care system, resulting from unplanned pregnancies and unsafe abortions. Health care staffs should be reoriented about the essential nature of safe abortion and family planning services during emergencies, and the implications of service disruption, on society and the country. Pragmatic and gender sensitive changes to national policies should be made, to ensure that women's health is safeguarded, and safe abortion and family planning included as essential health care services during emergencies.
Towards Minimal S4 Lepton Flavor Model
We study lepton flavor models with the flavor symmetry. We construct
simple models with smaller numbers of flavon fields and free parameters, such
that we have predictions among lepton masses and mixing angles. The model with
a triplet flavon is not realistic, but we can construct realistic models
with two triplet flavons, or one triplet and one doublet flavons.Comment: 18 pages, 4 figures, references are adde
'Mu-Tau' symmetry, tribimaximal mixing and four zero neutrino Yukawa textures
Within the type-I seesaw framework with three heavy right chiral neutrinos
and in the basis where the latter and the charged leptons are mass diagonal, a
near `mu-tau' symmetry in the neutrino sector is strongly suggested by the
neutrino oscillation data. There is further evidence for a close to the
tribimaximal mixing pattern which subsumes `mu-tau' symmetry. On the other
hand, the assumption of a (maximally allowed) four zero texture in the Yukawa
coupling matrix Y_nu in the same basis leads to a highly constrained and
predictive theoretical scheme. We show that the requirement of an exact
`mu-tau' symmetry, coupled with observational constraints, reduces the `seventy
two' allowed textures in such a `Y_nu' to 'only four' corresponding to just two
different forms of the light neutrino mass matrix `m_nu'. The effect of each of
these on measurable quantities can be described, apart from an overall factor
of the neutrino mass scale, in terms of two real parameters and a phase angle
all of which are within very constrained ranges. The additional input of a
tribimaximal mixing reduces these three parameters to `only one' with a very
nearly fixed value. Implications for both flavored and unflavored leptogenesis
as well as radiative lepton flavor violating decays are discussed. We also
investigate the stability of these conclusions under small deviations due to
renormalization group running from a high scale where the four zero texture as
well as `mu-tau' symmetry or the tribimaximal mixing pattern are imposed.Comment: Typographical changes,accepted for publication in JHE
Cultivation of Shiitake mushroom - a potential agro-industry for hilly areas of North Eastern India
74-78The survival and economic prosperity of various ethnic people of North eastern India largely depends upon rationale wise utilization and sustainable development of its local resources. Recently, Japanese wood mushroom commonly called as shiitake or golden oak mushroom [Lentinula edodes (Berk) Sing] has been explored for its large scale cultivation and production leading to conservation of biodiversity and economic upliftment of the local people. Shiitake mushroom is in high demand in the local markets due to its unique characteristic taste and usefulness in health care such as diabetes, hypertension, tumours, antiviral and as immuno-stimulant. On taking up its commercial cultivation one can earn a net profit of Rs. 4000 to 11,000 per annum from a mushroom cultivable shed of the size 4×4 m2
The Golden Ratio Prediction for the Solar Angle from a Natural Model with A5 Flavour Symmetry
We formulate a consistent model predicting, in the leading order
approximation, maximal atmospheric mixing angle, vanishing reactor angle and
tan {\theta}_12 = 1/{\phi} where {\phi} is the Golden Ratio. The model is based
on the flavour symmetry A5 \times Z5 \times Z3, spontaneously broken by a set
of flavon fields. By minimizing the scalar potential of the theory up to the
next-to-leading order in the symmetry breaking parameter, we demonstrate that
this mixing pattern is naturally achieved in a finite portion of the parameter
space, through the vacuum alignment of the flavon fields. The leading order
approximation is stable against higher-order corrections. We also compare our
construction to other models based on discrete symmetry groups.Comment: 28 pages, 2 figures. Minor changes, references added. Corrected typos
in Appendix A. Version appeared on JHE
Suppression of AP1 Transcription Factor Function in Keratinocyte Suppresses Differentiation
Our previous study shows that inhibiting activator protein one (AP1) transcription factor function in murine epidermis, using dominant-negative c-jun (TAM67), increases cell proliferation and delays differentiation. To understand the mechanism of action, we compare TAM67 impact in mouse epidermis and in cultured normal human keratinocytes. We show that TAM67 localizes in the nucleus where it forms TAM67 homodimers that competitively interact with AP1 transcription factor DNA binding sites to reduce endogenous jun and fos factor binding. Involucrin is a marker of keratinocyte differentiation that is expressed in the suprabasal epidermis and this expression requires AP1 factor interaction at the AP1-5 site in the promoter. TAM67 interacts competitively at this site to reduce involucrin expression. TAM67 also reduces endogenous c-jun, junB and junD mRNA and protein level. Studies with c-jun promoter suggest that this is due to reduced transcription of the c-jun gene. We propose that TAM67 suppresses keratinocyte differentiation by interfering with endogenous AP1 factor binding to regulator elements in differentiation-associated target genes, and by reducing endogenous c-jun factor expression
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