155 research outputs found
Gene transfer in bacteria from soils contaminated with heavy metals
Transfer of metal resistance plasmids into two pseudomonad recipients, Pseudomonas aureofaciens and Ps. putida, from soil bacteria donor populations, was investigated in agricultural soil contaminated predominantly with Zn and Cu. The putative donor and recipient numbers on selective agar were not affected by the concentration of metals in the soils, nor were the number of transconjugants. However, there were differences in transfer frequencies of Hg and Cu resistance from the different soil samples. This is the first time that transfer of Cu resistance has been observed from native bacteria present in agricultural soils
C2M: Configurable Chemical Middleware
One of the vexing problems that besets concurrent use of multiple, heterogeneous resources
is format multiplicity. C2M aims to equip scientists with a wrapper generator on their
desktop. The wrapper generator can build wrappers, or converters that can convert data
from or into different formats, from a high-level description of the formats. The language
in which such a high-level description is expressed is easy enough for scientists to be able to
write format descriptions at minimal cost. In C2M, wrappers and documentation for
human reading are automatically obtained from the same user-supplied specifications.
Initial experiments demonstrate that the idea can, indeed, lead to the advent of usergoverned
wrapper generators. Future research will consolidate the code and extend the
approach to a realistic variety of formats
Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model
A new critical survey is presented of all half-life, decay-energy and
branching-ratio measurements related to 20 0+ to 0+ beta decays. Compared with
our last review, there are numerous improvements: First, we have added 27
recently published measurements and eliminated 9 references; of particular
importance, the new data include a number of high-precision Penning-trap
measurements of decay energies. Second, we have used the recently improved
isospin symmetry-breaking corrections. Third, our calculation of the
statistical rate function now accounts for possible excitation in the daughter
atom. Finally, we have re-examined the systematic uncertainty associated with
the isospin symmetry-breaking corrections by evaluating the radial-overlap
correction using Hartree-Fock radial wave functions and comparing the results
with our earlier calculations, which used Saxon-Woods wave functions; the
provision for systematic uncertainty has been changed as a consequence. The new
corrected Ft values are impressively constant and their average, when combined
with the muon liftime, yields the up-down quark-mixing element of the
Cabibbo-Kobayashi-Maskawa (CKM) matrix, V_{ud} = 0.97425(22). The unitarity
test on the top row of the matrix becomes |V_{ud}|^2 + |V_{us}|^2 + |V_{ub}|^2
= 0.99995(61). Both V_{ud} and the unitarity sum have significantly reduced
uncertainties compared with our previous survey, although the new value of
V_{ud} is statistically consistent with the old one. From these data we also
set limits on the possible existence of scalar interactions, right-hand
currents and extra Z bosons. Finally, we discuss the priorities for future
theoretical and experimental work with the goal of making the CKM unitarity
test even more definitive.Comment: 36 pages, 11 tables, 9 figure
Superallowed nuclear beta decays: A critical survey with tests of CVC and the standard model
A complete and critical survey is presented of all half-life, decay-energy
and branching-ratio measurements related to 20 superallowed decays; no
measurements are ignored, though some are rejected for cause and others
updated. A new calculation of the statistical rate function is described and
experimental ft values determined. The associated theoretical corrections
needed to convert these results into Ft values are discussed, and careful
attention is paid to the origin and magnitude of their uncertainties. As an
exacting confirmation of the conserved vector current hypothesis, the Ft values
are seen to be constant to 3 parts in 10^4. These data are also used to set new
limits on any possible scalar interactions or right-hand currents. The average
Ft value obtained from the survey, when combined with the muon lifetime, yields
the CKM matrix element Vud = 0.9738(4); and the unitarity test on the top row
of the matrix becomes |Vud|^2 + |Vus|^2 + |Vub|^2 = 0.9966(14) using the PDG's
currently recommended values for Vus and Vub. We discuss the priorities for
future theoretical and experimental work with the goal of making the CKM
unitarity test more definitive.Comment: 64 pages, 4 postscript figure
Childrenâs Stories Supporting the Development of Critical Literacy and Intercultural Understanding
This chapter examines the possibilities of applying childrenâs storybooks in supporting the development of critical literacy as well as intercultural understanding. Valuing and supporting childrenâs reading is known to provide understanding and empathy towards other human beings. The chapter focuses on theoretical notions related to promoting critical literacies through childrenâs storybooks, but also includes practical examples of utilizing multicultural childrenâs stories. The chapter introduces different strategies that parents and teachers can use to support the development of critical literacy, including critical thinking and understanding multiple perspectives. Focus is especially on young children, because they already are capable of moving beyond what is in front of them on the page. Since childrenâs storybooks offer possibilities for readers to question implicit assumptions about self and others, books can support readers in becoming more culturally aware and sensitive. Consequently, reading storybooks can affect childrenâs intercultural understanding, and the role of storybooks in childrenâs moral development â both shaping and changing attitudes â should be seen as transformative.Peer reviewe
Post partum anxiety and depression in peri-urban communities of Karachi, Pakistan: a quasi-experimental study
<p>Abstract</p> <p>Background</p> <p>Postpartum anxiety and depression is a major public health concern because of its adverse effects on the cognitive and social development of the infant. Globally postpartum depression has been widely investigated but as anxiety is a more prominent feature of postpartum depression we assessed the prevalence of anxiety and depression and their associated factors in post partum women.</p> <p>Methods</p> <p>A quasi-experimental study investigating the impact of postpartum anxiety and depression on child growth and development was conducted in two peri-urban, multiethnic, communities of Karachi, a mega city of Pakistan. A house to house questionnaire based survey was done by trained field workers; 420 consenting pregnant women were identified and data for socio-demographic, home environment and family relationship variables was collected between 36 weeks of pregnancy and within 10 days of childbirth. Mother's levels of anxiety and depression were assessed after one month, two months, six months and twelve months of childbirth; this was two step process: initially an indigenous, validated screening instrument Aga Khan University Anxiety and Depression Scale was used and diagnostic confirmation was done through a psychologist's interview based on DSM IV criteria. Women found to be anxious and depressed at least once out of four assessments were considered for the computation of overall prevalence of postpartum anxiety and depression as well as its risk factors. However, point prevalence's of postpartum anxiety and depression were also reported at each assessment time. Two sixty seven women could be followed for one year. Data was analyzed using SPSS. Chi-square test, simple and multiple logistic regression were used to see the association of different factors.</p> <p>Results</p> <p>The overall prevalence of postpartum anxiety and depression was found to be 28.8 percent. Domestic violence, difficulty in breast feeding at birth and unplanned current pregnancy were found to be significantly associated with postpartum anxiety and depression.</p> <p>Conclusion</p> <p>Domestic violence and not having the right to plan pregnancy are related to the patriarchal culture and lack of empowerment of women. The association with difficulties in breast feeding needs to be further explored in future studies</p
What is the future for nuclear fission technology? A technical opinion from the Guest Editors of VSI NFT series and the Editor of the Journal Nuclear Engineering and Design
The Nuclear Fission Technology (NFT) series of Virtual Special Issues (VSIs) for the Journal Nuclear Engineering and Design (J NED) was proposed in 2023, including
the request to potential authors of manuscript to address the following questions:
o For how long will (water-cooling based) large size nuclear reactor survive?
o Will water-technology based SMRs displace large reactors?
o Will non-water-cooling technology SMRs and micro-reactors have an industrial deployment?
o Will breeding technology, including thorium exploitation, have due relevance?
o Will ânuclear infrastructureâ (fuel supply, financial framework, competence by regulators for new designs, waste management, etc.) remain or be
sufficiently robust?
Several dozen Guest Editors (GEs), i.e., the authors of the present document, managed the activity together with the Editor-in-Chief (EiC) of the
journal. More than one thousand scientists contributed 470+ manuscripts, not evenly distributed among the geographical regions of the world and not
necessarily addressing directly the bullet-questions, but certainly providing a view of current research being done.
Key conclusions are as follows: (a) Large size reactors are necessary for a sustainable and safe exploitation of nuclear fission technology; (b) The burning of 233U (from
thorium) and 239Pu (from uranium) is unavoidable, as well as recycling residual uranium currently part of waste; (c) Nuclear infrastructures in countries that
currently use, or are entering the use of, fission energy for electricity production need a century planning; (d) The adoption of small reactors for commercial naval
propulsion, hydrogen production and desalination is highly recommended
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