8,700 research outputs found
A method for rapidly evaluating the linearity of calibration data
Simple technique determines whether or not a set of five data points lies within a specified close tolerance of a linear fit
The State of Pakistan’s Dairy Sector : An Assessment
While there is a plethora of research documenting a multitude of dimensions of the crop sector of Pakistan, there is virtual absence of meaningful economic analysis of the dairy economy that is surprising. No serious attempt has been made in the past to clarify the micro-level potential of this sector in creating an impact on rural economy. This paper is a pioneering attempt to provide an objective assessment of the state of Pakistans dairy and to point out areas of further research. The paper analyzes some core issues and highlights the potentials, and recommends measures that could be adopted.dairy, rural economy, research areas
The State of Pakistan’s Dairy Sector: An Assessment
While there is a plethora of research documenting a multitude of dimensions of the crop sector of Pakistan, the virtual absence of meaningful economic analysis of the dairy economy is surprising. No serious attempt has been made in the past to clarify the microlevel potential of this sector to impact rural economy. This paper is a pioneering attempt to provide an objective assessment of the state of Pakistan’s dairy and to point out areas of further research. The paper analyses some core issues, highlights the potential of this sector, and recommends the measures to be adopted towards such a goal.Dairy Industry, Pakistan
Leptogenesis with heavy neutrino flavours: from density matrix to Boltzmann equations
Leptogenesis with heavy neutrino flavours is discussed within a density
matrix formalism. We write the density matrix equation, describing the
generation of the matter-antimatter asymmetry, for an arbitrary choice of the
right-handed (RH) neutrino masses. For hierarchical RH neutrino masses lying in
the fully flavoured regimes, this reduces to multiple-stage Boltzmann
equations. In this case we recover and extend results previously derived within
a quantum state collapse description. We confirm the generic existence of
phantom terms. However, taking into account the effect of gauge interactions,
we show that they are washed out at the production with a wash-out rate that is
halved compared to that one acting on the total asymmetry. In the N_1-dominated
scenario they cancel without contributing to the final baryon asymmetry. In
other scenarios they do not in general and they have to be taken into account.
We also confirm that there is a (orthogonal) component in the asymmetry
produced by the heavier RH neutrinos which completely escapes the washout from
the lighter RH neutrinos and show that phantom terms additionally contribute to
it. The other (parallel) component is washed out with the usual exponential
factor, even for weak washout. Finally, as an illustration, we study the two RH
neutrino model in the light of the above findings, showing that phantom terms
can contribute to the final asymmetry also in this case.Comment: 39 pages, 5 figures; v2: added Appendix and discussion in 2.2 on
lepton-antilepton flavour compositions difference (eq. (28) is a new result);
footnotes 4 and 5; new effect of gauge interactions in inducing wash-out of
phantom terms but with halved wash-out rate compared to the total asymmetry
wash-out rate; matches JCAP versio
Leptogenesis in the two right-handed neutrino model revisited
We revisit leptogenesis in the minimal non-supersymmetric type I see-saw
mechanism with two right-handed (RH) neutrinos, including flavour effects and
allowing both RH neutrinos N_1 and N_2 to contribute, rather than just the
lightest RH neutrino N_1 that has hitherto been considered. By performing scans
over parameter space in terms of the single complex angle z of the orthogonal
matrix R, for a range of PMNS parameters, we find that in regions around z \sim
\pm \pi/2, for the case of a normal mass hierarchy, the N_2 contribution can
dominate the contribution to leptogenesis, allowing the lightest RH neutrino
mass to be decreased by about an order of magnitude in these regions, down to
M_1 \sim 1.3*10^11 GeV for vanishing initial N_2-abundance, with the numerical
results supported by analytic estimates. We show that the regions around z \sim
\pm \pi /2 correspond to light sequential dominance, so the new results in this
paper may be relevant to unified model building.Comment: 41 pages, 10 figures; v2 matches published version in PR
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