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Herrera, G.
University of the Witwatersrand, Johannesburg (South Africa)1987
University of the Witwatersrand, Johannesburg (South Africa)1987
AbstractAbstract
[en] A gene bank of Agrobacterium tumefaciens D286 wt has been constructed by cloning D286 wt DNA partially digested with EcoRI in the cosmid vector pLAFRI. The library; composed of 1750 members with a 27.7 kb average insert size was probed with pCDTn5-3, a cosmid vector carrying a D286:: Tn5 insert from the strain D286:: Tn5 Ag-. One recombinant cosmid of the library, pCDO932, was detected. The insert DNA of pCDO932 has sequences homologous to the D286:: Tn5 insert of pCDTn5-3, therefore it carries putative wt agrocin D286 genes. The insert DNA of pCDO932 was isolated and used to probe the D286 wt gene library. Chromosome walking resulted in the detection of pCD2375. EcoRI restriction digestions and DNA homology studies of pCDO932 and pCD2375 showed that their D286 wt inserts are both composed of 4 EcoRI DNA sub-fragments totalling 21.8 and 24.8 kb respectively, with an overlapping sequence extending 3.5 kb. In order to overcome the failure to detect A. tumefaciens cells transformed with pCDO932. Vectors pSUP204-1 was constructed. Such vector has been derived from pSUP204 which were slightly altered by cloning into it a 700 bp λ DNA SalI fragmet. This resulted in insertion inactivation of the Tcr gene, allows the use of pSUP204-1 as a subcloning vector in conjugations and transformations involving pCDO932 or pCD2375 and strains D286:: Tn5 Ag- and C58 C1G. Two recombinant cosmids bearing D286 wt DNA inserts, at least one of which (pCDO932) contains DNA sequences putatively affecting agrocin D286 production, are now available for further genetic manipulations. pSUP204-1 should prove useful as a subcloning vector for transformations and conjugations involving recombinant cosmids from the D286 wt gene bank and Agrobacterium strains. Future work on the molecular biology of agrocin D286 production is discussed. The DNA probe used in this study was labelled with phosphorus 32
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Feb 1987; 124 p; Available from the Registrar, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, 2001, South Africa; Thesis (M.Sc.).
Record Type
Miscellaneous
Literature Type
Thesis/Dissertation; Numerical Data
Country of publication
BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, BIOLOGY, CELL CONSTITUENTS, CLONING, DATA, DAYS LIVING RADIOISOTOPES, DISEASES, DRUGS, GENES, INFORMATION, ISOTOPES, LIGHT NUCLEI, MICROORGANISMS, NUCLEI, NUCLEIC ACIDS, NUMERICAL DATA, ODD-ODD NUCLEI, ORGANIC COMPOUNDS, PHOSPHORUS ISOTOPES, RADIOISOTOPES
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AbstractAbstract
[en] The workshop provides courses and lectures in which students have the opportunity to learn about new trends in the field. There was a special session dedicated to Leon M. Lederman, who was awarded a medal by the Division of Particles and Fields of the Mexican Physical Society in recognition of his support in the creation of experimental high energy physics groups in Latin America. There are also parallel sessions of short seminars in which participants present their research work
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31 Dec 2000; 400 p; American Institute of Physics; Melville, NY (United States); Particles and Fields: Seventh Mexican Workshop; Merida, Yucatan (Mexico); 10-17 Nov 1999; ISBN 1-56396-954-8; ; ISSN 0094-243X; ; Available from American Institute of Physics, Melville, NY (US); CODEN APCPCS
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Book
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Conference
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Devine, R. A. B.; Herrera, G. V.
Funding organisation: (United States)2001
Funding organisation: (United States)2001
AbstractAbstract
[en] The temperature and time dependence of electric-field-induced motion of thermally generated protons in 20 nm amorphous SiO2 films has been investigated. The short-time behavior is found to involve an activation energy of ∼0.38 eV and a hopping distance of ∼0.55 nm. The activation energy is considerably smaller than that found for radiation-generated proton motion (∼0.82 eV). The hopping distance is consistent with transport involving motion between a bridging oxygen atom and a next-nearest-neighbor (or farther) bridging oxygen atom; this suggests that motion is primarily via cross-ring hopping
Source
Othernumber: PRBMDO000063000023233406000001; 047115PRB; The American Physical Society
Record Type
Journal Article
Journal
Physical Review. B, Condensed Matter and Materials Physics; ISSN 1098-0121; ; v. 63(23); p. 233406-233406.4
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Herrera, G.; Magnin, J.; Montano, Luis M.; Simao, F.R.A.
Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)1996
Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)1996
AbstractAbstract
[en] We study the ΛO polarization in the p+p -> ΛO + X reaction. In the framework of the Thomas precession model we use different recombination functions and see how their shape influences the polarization prediction. (author). 8 refs., 2 figs
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Feb 1996; 10 p; ISSN 0029-3865;
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Report
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AbstractAbstract
[en] The testing procedure was carried out in 1996-2 at the experimental station of the Universidad Nacional de Colombia in Palmira using vertical tillage (by chiseling) in coherent vertisol (typic Haplustert isohiperthermic fine loamy 1%). eight physical properties in depth of 15-25 cm were studied. the sampling methodology for soil physical properties and corn yield accounted the regionalized variable, and the analysis of results was carried out accounting a map of each variable. the results proved that geostatystics is versatile and give accuracy results. it showed in most of the area that vertical tillage was more favorable than conventional tillage to improve coherence (more soil penetrability without degradation) in seedbed zone. it was not found influence over corn yield. soil organic matter; clay and silt had influence over the soil response to mechanical strengths
Original Title
La variabilidad espacial en el estudio de la condicion fisica del suelo
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Journal Article
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Acta Agronomica (Palmira); ISSN 0120-2812; ; v. 50(No.3-4); p. 38-43
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AbstractAbstract
[en] We study the polarization of Λ04s produced in heavy ion collisions. Using the Thomas Precession Model to describe the Λ0 polarization we observed that dose Λ0 produced below some critical nuclear density should be polarized. We assume that there are two mechanisms at work for the Λ0 production in heavy-ion collisions. The polarization would depend on how large is the contribution of one of the two processes to the total Λ0 production. (Author)
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AbstractAbstract
[en] Ground subsidence caused by aquifer withdrawal is a geotechnical hazard that affects wide areas, causing high economic losses. This phenomenon id due to aquifer system fine soil consolidation produced by the increase of effective stress caused by piezo metric depletion. The Vega Media of the Segura River basin (SE Spain) has suffered this type of phenomena since 90s being until the moment the first documented case at a regional scale in Spain. In this work a Differential SAR Interferometry (DInSAR) remote sensing technique called Coherent Pixel (CPT) is applied to monitoring subsidence in the Vega Media of the Segura River using 81 SAR images provided by ERS-1, ERS-2 and ENVISAT European Space Agency satellites. The processing has provided the subsidence spatial distribution and temporal evolution for the whole study area showing maximum subsidence values near 15 cm for the 1994-2007 period. (Author) 33 refs.
Original Title
Monitorizacion de la subsidencia del terreno de la Vega Media del rio SAR Diferencial Avanzada
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Journal Article
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Ingenieria Civil (Madrid); CODEN ICIVE7; v. 158; p. 93-102
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Montano, Luis M.; Herrera, G.
Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)1996
Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)1996
AbstractAbstract
[en] We explore the possibility to resolve an intrinsic charm Fock state in the proton studying the Λc+ polarization in proton collisions. (author). 8 refs., 2 figs
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Feb 1996; 12 p; ISSN 0029-3865;
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Report
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Herrera, G; Ramirez, A; Sanmiguel, R.
X Latin American Symposium on Nuclear Physics and Applications. Book of Abstracts2013
X Latin American Symposium on Nuclear Physics and Applications. Book of Abstracts2013
AbstractAbstract
[en] A set-up for X-Ray Imaging was mounted using a micro source X-ray generator, a Shad-O Box detector and a X-ray Imaging Plate System. We implemented the in-line phase contrast technique in our laboratory. Phase contrast imaging is an emerging X-ray imaging technique capable of improving the conspicuity of fine detail in an image, including some detail which are not visible with conventional techniques. The application of phase contrast imaging techniques to medical diagnostics (e.g. mammography) and the new segmentation adaptative algorithms based in entropy has opened new horizons for X-ray based imaging. The ROI (Region Of Interest) extraction is an important step in de X-ray imaging processing, because it reduces the computational cost. The classical spatial filters used in image segmentation show different results when the dimension of an image changes, this implies modifying the algorithm and it takes longer. The phase contrast technique shows better detail information. In order to avoid different results on images with variable dimensions, we used the non extensive systems concept applied to images through Tsallis entropy that assumes subsets of probabilities for different regions in the X-ray image. The ROI extraction based on Tsallis entropy and phase contrast X-ray images offers high quality region extraction and therefore more accurate diagnoses
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Universidad de la Republica, Facultad de Ingenieria, Facultad de Ciencias, Montevideo (Uruguay); National Superconducting Cyclotron Laboratory, Michigan, (United States); Thomas Jefferson National Accelerator Facility, Virginia (United States); [187 p.]; Dec 2013; 1 p; 10. Latin American Symposium; Montevideo (Uruguay); 1-6 Dec 2013; Poster contributions
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Miscellaneous
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Conference
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[en] We study the inclusive production of charged and neutral pions in the reactions p↑p→φX and anti p↑p→φX in the framework of single spin asymmetries. We propose a two components model where production of pions occurs both by recombination of the constituents present in the initial state and by fragmentation of quarks in the final state. Taking the Thomas precession mechanism in the recombination component into account, we obtain a good description of the experimentally observed single spin asymmetries. We show that the observed single spin asymmetries are consistent with the measured spin alignment in the polarized proton as measured by HERMES and SMC. (orig.)
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Journal Article
Literature Type
Numerical Data
Journal
European Physical Journal. C; ISSN 1434-6044; ; v. 20(4); p. 677-682
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BARYON-BARYON INTERACTIONS, BEAMS, BOSONS, DATA, ELEMENTARY PARTICLES, HADRON-HADRON INTERACTIONS, HADRONS, INFORMATION, INTERACTIONS, MESONS, NUCLEON-ANTINUCLEON INTERACTIONS, NUCLEON-NUCLEON INTERACTIONS, NUMERICAL DATA, ORIENTATION, PARTICLE INTERACTIONS, PIONS, PROTON-NUCLEON INTERACTIONS, PSEUDOSCALAR MESONS
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