489 research outputs found
Water as an economic good in irrigated agriculture: theory and practice
This report describes the results of the Water Valuation and Pricing project, which aims to provide insight into the relevance of economics to typical problems found in irrigated agriculture. It first considers the theoretical basis for the use of economic instruments, then considers their usefulness in the context of five case studies of irrigated areas - in Egypt, India, Indonesia, Morocco and Ukraine. The case studies confirm that competition for scarce water and shortage of funds are widespread. The study provides insight into the current price paid for water, the cost of service provision, and the value to irrigators of the water they receive. The analysis shows that volumetric pricing is unlikely to be relevant to demand management because the price of water at which demand and supply would be balanced is so high as to substantially reduce farm incomes. This socio-political problem, plus the technical and administrative complexity of measuring and accounting for water, and the crucial distinction between water applied to the field and water consumed by the crop make water pricing an unsuitable approach to balancing supply and demand
Structure of the ovaries of the Nimba otter shrew, Micropotamogale lamottei, and the Madagascar hedgehog tenrec, Echinops telfairi
The otter shrews are members of the subfamily Potamogalinae within the family Tenrecidae. No description of the ovaries of any member of this subfamily has been published previously. The lesser hedgehog tenrec, Echinops telfairi, is a member of the subfamily Tenrecinae of the same family and, although its ovaries have not been described, other members of this subfamily have been shown to have ovaries with non-antral follicles. Examination of these two species illustrated that non-antral follicles were characteristic of the ovaries of both species, as was clefting and lobulation of the ovaries. Juvenile otter shrews range from those with only small follicles in the cortex to those with 300- to 400-mu m follicles similar to those seen in non-pregnant and pregnant adults. As in other species, most of the growth of the oocyte occurred when follicles had one to two layers of granulosa cells. When larger follicles became atretic in the Nimba otter shrew, hypertrophy of the theca interna produced nodules of glandular interstitial tissue. In the tenrec, the hypertrophying theca interna cells in most large follicles appeared to undergo degeneration. Both species had some follicular fluid in the intercellular spaces between the more peripheral granulosa cells. It is suggested that this fluid could aid in separation of the cumulus from the remaining granulosa at ovulation. The protruding follicles in lobules and absence of a tunica albuginea might also facilitate ovulation of non-antral follicles. Ovaries with a thin-absent tunica albuginea and follicles with small-absent antra are widespread within both the Eulipotyphla and in the Afrosoricida, suggesting that such features may represent a primitive condition in ovarian development. Lobulated and deeply crypted ovaries are found in both groups but are not as common in the Eulipotyphla making inclusion of this feature as primitive more speculative. Copyright (C) 2005 S. Karger AG, Basel
PEACH™ Queensland program improved child eating behaviours and reduced BMI z-score for overweight children (pilot study)
Background/Aims: Parenting, Eating and Activity for Child Health (PEACH™) Queensland is a 6-month family-focussed child weight management program currently targeting 1400 Queensland children. This study aims to investigate changes in child BMI and eating behaviours during the pilot phase. Methods: From 2013 – 2014, 251 overweight children (US-CDC BMI percentile ≥ 85th) were enrolled in the pilot phase of PEACH™ Queensland, using pre-defined inclusion criteria which included having a child above a healthy weight for their age (5 – 11 years). Baseline and follow-up data were collected from parents by questionnaire and included child eating behaviours, measured by core food intake and Children’s Dietary Questionnaire (CDQ). Children attending sessions were weighed and measured by a trained facilitator. Results: Children attending sessions were 80% obese (IOTF cut-points), 60% female, with average age of 9.0 ± 1.9 years. For the subset of children with complete anthropometry (n = 69), we observed significant decreases in US-CDC z-scores for weight and BMI, 2.3 ± 0.7 to 2.2 ± 0.7 (p < 0.001) and 2.2 ± 0.5 to 2.1 ± 0.7 (p < 0.0001), respectively. This reduction in BMI z-score was accompanied by increases in the proportion meeting recommendations for serves of fruit and vegetables, and significantly lower scores for sweetened beverages and discretionary food intake as measured by CDQ. Conclusions: The PEACH™ Queensland pilot reduced child weight and BMI z-scores, and improved eating behaviours (increased fruit and vegetable intake, decreased intake of discretionary foods and sweetened beverages) although there is need for further improvement
Self-consistent solution of the Schwinger-Dyson equations for the nucleon and meson propagators
The Schwinger-Dyson equations for the nucleon and meson propagators are
solved self-consistently in an approximation that goes beyond the Hartree-Fock
approximation. The traditional approach consists in solving the nucleon
Schwinger-Dyson equation with bare meson propagators and bare meson-nucleon
vertices; the corrections to the meson propagators are calculated using the
bare nucleon propagator and bare nucleon-meson vertices. It is known that such
an approximation scheme produces the appearance of ghost poles in the
propagators. In this paper the coupled system of Schwinger-Dyson equations for
the nucleon and the meson propagators are solved self-consistently including
vertex corrections. The interplay of self-consistency and vertex corrections on
the ghosts problem is investigated. It is found that the self-consistency does
not affect significantly the spectral properties of the propagators. In
particular, it does not affect the appearance of the ghost poles in the
propagators.Comment: REVTEX, 7 figures (available upon request), IFT-P.037/93,
DOE/ER/40427-12-N9
Effect of tensor couplings in a relativistic Hartree approach for finite nuclei
The relativistic Hartree approach describing the bound states of both
nucleons and anti-nucleons in finite nuclei has been extended to include tensor
couplings for the - and -meson. After readjusting the parameters
of the model to the properties of spherical nuclei, the effect of
tensor-coupling terms rises the spin-orbit force by a factor of 2, while a
large effective nucleon mass sustains. The overall
nucleon spectra of shell-model states are improved evidently. The predicted
anti-nucleon spectra in the vacuum are deepened about 20 -- 30 MeV.Comment: 31 pages, 4 postscript figures include
The distribution of heartwater in the highveld of Zimbabwe, 1980-1997
Heartwater, the tick-borne disease caused by the rickettsia Cowdria ruminantium has historically been
confined to the southern and western lowvelds of Zimbabwe. Since 1986, however, cases of heartwater
have been diagnosed with increasing frequency in the central and eastern regions of the previously
heartwater-free highveld plateau. During the same period, collections of the two major tick
vectors of heartwater in Zimbabwe, Amblyomma hebraeum and Amblyomma variegatum, were made
for the first time in these areas, suggesting that spread of these ticks was responsible for the changed
distribution of the disease. The factors associated with this spread have not been determined, but
increased cattle and wildlife movement and reduced intensity of dipping undoubtedly play important
roles. Currently, the distribution of heartwater and its vectors in the highveld is still largely restricted
to the central and eastern regions. The northern regions of the highveld appear to be predominantly
uninfected, though it is likely that, eventually, heartwater will spread further with considerable impact
on livestock production in Zimbabwe.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.United States Agency tor International Development.mn201
Seismology of the Sun : Inference of Thermal, Dynamic and Magnetic Field Structures of the Interior
Recent overwhelming evidences show that the sun strongly influences the
Earth's climate and environment. Moreover existence of life on this Earth
mainly depends upon the sun's energy. Hence, understanding of physics of the
sun, especially the thermal, dynamic and magnetic field structures of its
interior, is very important. Recently, from the ground and space based
observations, it is discovered that sun oscillates near 5 min periodicity in
millions of modes. This discovery heralded a new era in solar physics and a
separate branch called helioseismology or seismology of the sun has started.
Before the advent of helioseismology, sun's thermal structure of the interior
was understood from the evolutionary solution of stellar structure equations
that mimicked the present age, mass and radius of the sun. Whereas solution of
MHD equations yielded internal dynamics and magnetic field structure of the
sun's interior. In this presentation, I review the thermal, dynamic and
magnetic field structures of the sun's interior as inferred by the
helioseismology.Comment: To be published in the proceedings of the meeting "3rd International
Conference on Current Developments in Atomic, Molecular, Optical and Nano
Physics with Applications", December 14-16, 2011, New Delhi, Indi
Distribution maps of cetacean and seabird populations in the North‐East Atlantic
1. Distribution maps of cetaceans and seabirds at basin and monthly scales are needed for conservation and marine management. These are usually created from standardized and systematic aerial and vessel surveys, with recorded animal den- sities interpolated across study areas. However, distribution maps at basin and monthly scales have previously not been possible because individual surveys have restricted spatial and temporal coverage.
2. This study develops an alternative approach consisting of: (a) collating diverse survey data to maximize spatial and temporal coverage, (b) using detection func- tions to estimate variation in the surface area covered (km2) among these surveys, standardizing measurements of effort and animal densities, and (c) developing species distribution models (SDM) that overcome issues with heterogeneous and uneven coverage.
3. 2.68 million km of survey data in the North-East Atlantic between 1980 and 2018 were collated and standardized. SDM using Generalized Linear Models and General Estimating Equations in a hurdle approach were developed. Distribution maps were then created for 12 cetacean and 12 seabird species at 10 km and monthly resolution. Qualitative and quantitative assessment indicated good model performance.
4. Synthesis and applications. This study provides the largest ever collation and standardization of diverse survey data for cetaceans and seabirds, and the most comprehensive distribution maps of these taxa in the North-East Atlantic. These distribution maps have numerous applications including the identification of im- portant areas needing protection, and the quantification of overlap between vul- nerable species and anthropogenic activities. This study demonstrates how the analysis of existing and diverse survey data can meet conservation and marine management needs.Versión del editor4,7
Variation with mass of B(E3;01+→31-) transition rates in A=124-134 even-mass xenon nuclei
B(E3;01+→31-) transition matrix elements have been measured for even-mass Xe124-134 nuclei using subbarrier Coulomb excitation in inverse kinematics. The trends in energy E(3-) and B(E3;01+→31-) excitation strengths are well reproduced using phenomenological models based on a strong coupling picture with a soft quadrupole mode and an increasing occupation of the intruder h11/2 orbital
Genomic basis for RNA alterations in cancer
Transcript alterations often result from somatic changes in cancer genomes. Various forms of RNA alterations have been described in cancer, including overexpression, altered splicing and gene fusions; however, it is difficult to attribute these to underlying genomic changes owing to heterogeneity among patients and tumour types, and the relatively small cohorts of patients for whom samples have been analysed by both transcriptome and whole-genome sequencing. Here we present, to our knowledge, the most comprehensive catalogue of cancer-associated gene alterations to date, obtained by characterizing tumour transcriptomes from 1,188 donors of the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). Using matched whole-genome sequencing data, we associated several categories of RNA alterations with germline and somatic DNA alterations, and identified probable genetic mechanisms. Somatic copy-number alterations were the major drivers of variations in total gene and allele-specific expression. We identified 649 associations of somatic single-nucleotide variants with gene expression in cis, of which 68.4% involved associations with flanking non-coding regions of the gene. We found 1,900 splicing alterations associated with somatic mutations, including the formation of exons within introns in proximity to Alu elements. In addition, 82% of gene fusions were associated with structural variants, including 75 of a new class, termed 'bridged' fusions, in which a third genomic location bridges two genes. We observed transcriptomic alteration signatures that differ between cancer types and have associations with variations in DNA mutational signatures. This compendium of RNA alterations in the genomic context provides a rich resource for identifying genes and mechanisms that are functionally implicated in cancer
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