137 research outputs found
Effect of water and straw management practices on methane emissions from rice fields: A review through a meta-analysis
[EN] Rice fields contribute substantially to global warming of the atmosphere through emission of methane (CH4). This article reviews the state of the art of factors affecting CH4 emissions in rice fields, focusing on soil organic matter content and water management practices. A quantitative relationship between these factors was established through a meta-analysis based on a literature survey. This relationship can be useful to update emission factors used to estimate CH4 in the National Emission Inventories. Methane emissions in rice fields can be as much as 90% higher in continuously flooded rice fields compared with other water management practices, independent from straw addition. Water management systems that involve absence of flooding in total or for part of the growing period such as midseason drainages, intermittent flooding, and percolation control, can reduce CH4 emissions substantially. Moreover, CH4 emissions increase with the amount of straw added up to 7.7 t/ha for continuously flooded soils and up to 5.1 t/ha for other water regimes. Above these levels, no further increase is produced with further addition of straw. With regard to rice straw management mitigation strategies, recommended practices are composting rice straw, straw burning under controlled conditions, recollecting rice straw for biochar production, generation of energy, to be used as a substrate, or to obtain other byproducts with added value. This review improves the understanding of the relationship between straw application rate, water regimes, and CH4 emissions from rice fields to date. This relationship can help to select the most appropriate management practices to improve current mitigation strategies to reduce atmospheric CH4. © 2012 Mary Ann Liebert, Inc.This study was financially supported by Fundacio´n Agroalimed from the Consellerı´a de Agricultura of Valencia, Spain and the Vicerrectorado de Investigacio´n of the UPV (Programa de Apoyo a la Investigacio´n y Desarrollo, PAID06-11 Program, Project No. 1950).Sanchís Jiménez, EM.; Ferrer Roglán, M.; Torres, AG.; Cambra López, M.; Calvet Sanz, S. (2012). Effect of water and straw management practices on methane emissions from rice fields: A review through a meta-analysis. Environmental Engineering Science. 29(12):1053-1062. https://doi.org/10.1089/ees.2012.0006S10531062291
Two neutrino positron double beta decay of Cd for transition
The two neutrino positron double beta decay of Cd for 0
0 transition has been studied in the Hartree-Fock-Bogoliubov model in
conjunction with the summation method. In the first step, the reliability of
the intrinsic wave functions of Cd and Pd nuclei has been
tested by comparing the theoretically calculated results for yrast spectra,
reduced : transition probabilities, quadrupole moments
and gyromagnetic factors with the available experimental
data. In the second step, the nuclear transition matrix element and
the half-life for 0 0 transition have been
calculated with these wave functions. Moreover, we have studied the effect of
deformation on nuclear transition matrix element MComment: 20 page
Nuclear deformation and the two neutrino double-\beta decay in ^{124,126}Xe,^{128,130}Te, ^{130,132}Ba and ^{150}Nd isotopes
The two neutrino double beta decay of Xe,Te, Ba and Nd isotopes is studied in the Projected
Hartree-Fock-Bogoliubov (PHFB) model. Theoretical 2
half-lives of Te, and Nd isotopes, and 2, 2 and 2 for Xe and Ba nuclei are presented. Calculated quadrupolar
transition probabilities B(E2: ), static quadrupole moments and
factors in the parent and daughter nuclei reproduce the experimental
information, validating the reliability of the model wave functions. The
anticorrelation between nuclear deformation and the nuclear transition matrix
element is confirmed.Comment: 19 page
Profile: Agincourt health and socio-demographic surveillance system.
The Agincourt health and socio-demographic surveillance system (HDSS), located in rural northeast South Africa close to the Mozambique border, was established in 1992 to support district health systems development led by the post-apartheid ministry of health. The HDSS (90 000 people), based on an annual update of resident status and vital events, now supports multiple investigations into the causes and consequences of complex health, population and social transitions. Observational work includes cohorts focusing on different stages along the life course, evaluation of national policy at population, household and individual levels and examination of household responses to shocks and stresses and the resulting pathways influencing health and well-being. Trials target children and adolescents, including promoting psycho-social well-being, preventing HIV transmission and reducing metabolic disease risk. Efforts to enhance the research platform include using automated measurement techniques to estimate cause of death by verbal autopsy, full 'reconciliation' of in- and out-migrations, follow-up of migrants departing the study area, recording of extra-household social connections and linkage of individual HDSS records with those from sub-district clinics. Fostering effective collaborations (including INDEPTH multi-centre work in adult health and ageing and migration and urbanization), ensuring cross-site compatibility of common variables and optimizing public access to HDSS data are priorities
Perspectives from the 2nd International Post-Tuberculosis Symposium: mobilising advocacy and research for improved outcomes
In 2020, it was estimated that there were 155 million survivors of TB alive, all at risk of possible post TB disability. The 2nd International Post-Tuberculosis Symposium (Stellenbosch, South Africa) was held to increase global awareness and empower TB-affected communities to play an active role in driving the agenda. We aimed to update knowledge on post-TB life and illness, identify research priorities, build research collaborations and highlight the need to embed lung health outcomes in clinical TB trials and programmatic TB care services. The symposium was a multidisciplinary meeting that included clinicians, researchers, TB survivors, funders and policy makers. Ten academic working groups set their own goals and covered the following thematic areas: 1) patient engagement and perspectives; 2) epidemiology and modelling; 3) pathogenesis of post-TB sequelae; 4) post-TB lung disease; 5) cardiovascular and pulmonary vascular complications; 6) neuromuscular & skeletal complications; 7) paediatric complications; 8) economic-social and psychological (ESP) consequences; 9) prevention, treatment and management; 10) advocacy, policy and stakeholder engagement. The working groups provided important updates for their respective fields, highlighted research priorities, and made progress towards the standardisation and alignment of post-TB outcomes and definitions
Chitosan–Starch–Keratin composites: Improving thermo-mechanical and degradation properties through chemical modification
The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73 % for chitosan-starch matrix up to 16 % for the composites with 5wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiat-ing chitosan–starch films with sustainable featuresChitosan–starch polymers are reinforced with different keratin materials obtained from chicken feather. Keratin materials are treated with sodium hydroxide; the modified surfaces are rougher in comparison with untreated surfaces, observed by Scanning Electron Microscopy. The results obtained by Differential Scanning Calorimetry show an increase in the endothermic peak related to water evaporation of the films from 92 °C (matrix) up to 102–114 °C (reinforced composites). Glass transition temperature increases from 126 °C in the polymer matrix up to 170–200 °C for the composites. Additionally, the storage modulus in the composites is enhanced up to 1614 % for the composites with modified ground quill, 2522 % for composites with modified long fiber and 3206 % for the composites with modified short fiber. The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73 % for chitosan-starch matrix up to 16 % for the composites with 5wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiat-ing chitosan–starch films with sustainable featuresUniversidad Autónoma del Estado de México Tecnológico Nacional de México, Instituto Tecnológico de Querétaro Universidad Nacional Autónoma de México Tecnológico Nacional de México, Instituto Tecnológico de Celaya Universidad Autónoma de Cd. Juáre
A systematic study of band structure and electromagnetic properties of neutron rich odd mass Eu isotopes in the projected shell model framework
The positive and negative parity rotational band structure of the neutron rich odd mass Eu isotopes with neutron numbers ranging from 90 to 96 are investigated up to the high angular momentum. In the theoretical analysis of energy spectra, transition energies and electromagnetic transition probabilities we employ the projected shell model. The calculations successfully describe the formation of the ground and excited band structures from the single particle and multi quasiparticle configurations. Calculated excitation energy spectra, transition energies, exact quantum mechanically calculated B(E2) and B(M1) transition probabilities are compared with experimental data wherever available and a reasonably good agreement is obtained with the observed data. The change in deformation in the ground state band with the increase in angular momentum and the increase in neutron number has also been established
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Improving learning in South African schools: the QLP baseline evaluation
The Quality Learning Project (QLP) is a five-year school improvement project intended to facilitate educational change in South Africa by working with district officials, school management teams and educators. The aim of the project is to improve learner performance in mathematics and the languages of instruction in Grades 8-12 in 500 schools across 17 districts
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