23,825 research outputs found
Numerical computation of real or complex elliptic integrals
Algorithms for numerical computation of symmetric elliptic integrals of all
three kinds are improved in several ways and extended to complex values of the
variables (with some restrictions in the case of the integral of the third
kind). Numerical check values, consistency checks, and relations to Legendre's
integrals and Bulirsch's integrals are included
Limnological research in Nigeria: some perspectives
A brief review on limnological research in Nigeria is given: the status of the research in the country and perspectives for future development are illustrate
Approaches and methods for monitoring and evaluation
The aim of many agricultural innovation networks is to realize a system innovation. With system innovation, whole production and consumption systems change, including social relationships, division of roles, formal rules and values, and the technical artefacts and infrastructure. This type of innovation takes place when stakeholders learn from each other in a process of thinking and acting together. In order to get to grips with these learning processes, it is increasingly common to use monitoring and evaluation methods. What are the methods that can be used, what are the most significant differences between them and to what degree are the methods from the different approaches of use in evaluating and managing innovation projects
Economic and Ecological Benefits of System of Rice Intensification (SRI) in Tamil Nadu
The paper has quantified the benefits of SRI over non-SRI practices of rice cultivation in Tamil Nadu. The SRI practices have been found to save inputs substantially and to increase returns. Higher return has been attributed to increase in production as well as substantial reduction in cost of cultivation. The most impressive are the savings in water (22-39 per cent ) and seed (92 per cent). The organic supplementation due to green manuring and weed incorporation, enhanced soil microbial activities and aeration, use of solar energy and time saving due to early transplantation, are some of the uncommon advantages of SRI. The women employment in specialized operations such as transplanting, harvesting and weedings can lead to gender equity. The estimates of technical efficiency using DEAP has clearly shown that SRI is more technical and economic efficient. Upscaling of SRI strategy will help achieve national as well as household food-security.Agricultural and Food Policy,
On Plouffe's Ramanujan Identities
Recently, Simon Plouffe has discovered a number of identities for the Riemann
zeta function at odd integer values. These identities are obtained numerically
and are inspired by a prototypical series for Apery's constant given by
Ramanujan: Such sums follow from a general relation given by Ramanujan, which is
rediscovered and proved here using complex analytic techniques. The general
relation is used to derive many of Plouffe's identities as corollaries. The
resemblance of the general relation to the structure of theta functions and
modular forms is briefly sketched.Comment: 19 pages, 3 figures; v4: minor corrections; modified intro; revised
concluding statement
Process controls on the development of stratigraphic trap potential on the margins of confined turbidite systems and aids to reservoir evaluation
Stratigraphic trapping at pinch-out margins is a key feature of many
turbidite-hosted hydrocarbon reservoirs. In systems confined by lateral
or oblique frontal slopes, outcrop studies show that there is a
continuum between two geometries of pinch-out configuration. In
type A, turbidites thin onto the confining surface—although the
final sandstone pinch-out is commonly abrupt—and individual beds
tend not to erode into earlier deposits. In type B, turbidite sandstones
commonly thicken toward the confining slope, and beds may
incise into earlier deposits. These two types may occur in combination,
to give a wide spectrum of pinch-out characteristics. Our
analysis suggests the principal control in determining pinch-out
character is flow magnitude, with smaller flows producing type A
and larger flows producing type B.
In areas of poor seismic control it can be difficult to assess either
pinch-out character or the proximity of wells to confining slopes.
Because estimates of paleoflow magnitude can be made from core
or high-quality log image data, however, it is possible to make reasonable
estimates of pinch-out character even from wells such as
exploration wells, which may be placed conservatively, away from
the field margins. Furthermore, systematic paleoflow variations and
thickness trends are commonly seen in individual turbidite sandstones
as they approach confining slopes. For example, dispersal
directions indicate flow deflection parallel with the strike of confining
topography; beds thin toward type A onlaps and thicken toward
type Bonlaps. These relationships can be exploited via analysis of
vertical successions to constrain well position with respect to the
slope. Similarly, the presence, location, and frequency of locally
derived debrites can provide information on the presence and proximity
of confining slopes
Further comments-Waihi Terrace and Hamilton Ash Ages
The authors of the previous paper (Selby et al. 1971) kindly allowed us to see their manuscript, prior to publication. They have made a significant contribution to Bay of Plenty late Quaternary stratigraphy in recognising established ash beds in the coastal terrace sequence at Waihi Beach (Kear & Waterhouse, 1961). This brief note acknowledges their work, and uses their data to produce an alternative age interpretation, that implies broad dates for the formation of each of the coastal terraces and for the Hamilton Ash
Vertex operators for the plane wave pure spinor string
Indexación: Scopus.We would like to thank William Linch for useful discussions and comments on the draft. The work of Bcv is partially supported by FONDECYT grant number 1151409 and CON-ICYT grant number DPI20140115.In this work we give an explicit construction for the vertex operators of massless states in the pure spinor superstring in a plane wave background. The construction is based on the observation that the full action can be divided in two parts, where the simpler one is based on a smaller coset and closely resembles the gauge fixed Green-Schwarz action. © 2018, The Author(s).https://link.springer.com/article/10.1007%2FJHEP10%282018%2908
The 5 ' untranslated region of protein kinase C delta directs translation by an internal ribosome entry segment that is most active in densely growing cells and during apoptosis.
Protein kinase Cdelta (PKCdelta) is a member of the PKC family of phospholipid-dependent serine/threonine kinases and is involved in cell proliferation, apoptosis, and differentiation. Previous studies have suggested that different PKC isoforms might be translationally regulated. We report here that the 395-nt-long 5' untranslated region (5' UTR) of PKCdelta is predicted to form very stable secondary structures with free energies (DeltaG values) of around -170 kcal/mol. The 5' UTR of PKCdelta can significantly repress luciferase translation in rabbit reticulocyte lysate but does not repress luciferase translation in a number of transiently transfected cell lines. By using a bicistronic luciferase reporter, we show that the 5' UTR of PKCdelta contains a functional internal ribosome entry segment (IRES). The activity of the PKCdelta IRES is greatest in densely growing cells and during apoptosis, when total protein synthesis and levels of full-length eukaryotic initiation factor 4G are reduced. However, the IRES activity of the 5' UTR of PKCdelta is not enhanced during serum starvation, another condition shown to inhibit cap-dependent translation, suggesting that its potency is dependent on specific cellular conditions. Accumulating data suggest that PKCdelta has a function as proliferating cells reach high density and in early and later events of apoptosis. Our studies suggest a mechanism whereby PKCdelta synthesis can be maintained under these conditions when cap-dependent translation is inhibited
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