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Search Results: 1 - 10 of 466920 matches for " A. Nelson "
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Synthesis and Characterization of Poly(styrene-co-acrylamide) Polymers Prior to Electrospinning  [PDF]
Adebola A. Oketola, Nelson Torto
Advances in Nanoparticles (ANP) , 2013, DOI: 10.4236/anp.2013.22015

Electrospun nanofibers present a new and rapidly growing research area due to their pronounced micro and nano characteristics associated with high surface area to volume ratio. Poly(styrene-co-acrylamide) and polystyrene polymers were synthesized by boiling temperature soap free emulsion polymerization in aqueous medium with potassium peroxosulphate as the initiator. The resulting polymers were dissolved in dimethylformamide and teterahydrofuran (DMF: THF) (4:1) to form polymer solutions that were electrospun into fiber mats with diameters ranging from 1.84 - 2.53 μm and 5.01 μm, respectively. The fibers were characterized by Fourier transform infrared spectroscopy (FTIR) equipped with universal ATR sampling accessory (4000 - 400 cm-1). The morphology and size were examined by a scanning electron miscroscope (SEM) and the thermal properties by thermogravimetric analysis (TGA). The FTIR spectra of the poly(styrene-co-acrylamide) revealed the presence of acrylamide on the polystyrene chain. Thus, surface modification of polystyrene with acrylamide is possible in a single step polymerization reaction prior to electrospinning.

Tomonaga-Luttinger Unusual Exponents around Fermi Points in the One-Dimensional Hubbard Model  [PDF]
Nelson O. Nenuwe, John O. A. Idiodi
World Journal of Condensed Matter Physics (WJCMP) , 2015, DOI: 10.4236/wjcmp.2015.52012
Abstract: We study the correlation functions of one-dimensional Hubbard model in the presence of external magnetic field through the conformal field method. The long distance behaviour of the correlation functions and their unusual exponents for the model in the presence of a magnetic field are developed by solving the dressed charge matrix equations and setting the number of occupancies \"\"?to one, as alternative to the usual zero used by authors in literatures. This work shows that the exponent of the correlation functions is a monotonous function of magnetic field and the correlation functions decay as powers of these unusual exponents. As the magnetic field goes to zero, we obtain the exponents as 8.125, 11.125, 17.125, 26.125 and 38.125 at kF, 3kF, 5kF, 7kF and 9kF. Our analytical results will provide insights into criticality in condensed matter physics.
Evidence-Based Practices for Safe Patient Handling and Movement
Nelson, A., Baptiste, A
Online Journal of Issues in Nursing , 2004,
Abstract: Efforts to reduce injuries associated with patient handling are often based on tradition and personal experience rather than scientific evidence. The purpose of this article is to summarize current evidence for interventions designed to reduce caregiver injuries, a significant problem for decades. Despite strong evidence, published over three decades, the most commonly used strategies have strong evidence that demonstrate they are ineffective. There is a growing body of evidence to support newer interventions that are effective or show promise in reducing musculoskeletal pain and injuries in care providers. The authors have organized potential solutions into three established ergonomic solution types: engineering based, administrative, and behavioral. For each intervention, the level of evidence to support its use is provided.
Supersymmtric Baryogenesis
A. Cohen,A. Nelson
Physics , 1992, DOI: 10.1016/0370-2693(92)91078-N
Abstract: Requiring that the baryon number of the universe be generated by anomalous electroweak interactions places strong constraints on the minimal supersymmetric standard model. In particular, the electric dipole moment of the neutron must be greater than $10^{-27}$e-cm. Improvement of the current experimental bound on the neutron's electric dipole moment by one order of magnitude would constrain the lightest chargino to be lighter than 88 GeV, and the the lightest neutralino to be lighter than 44 GeV. In extensions of this model with gauge singlet superfields all of these bounds are eliminated.
Caracterización socio-educativa de una comunidad Warao: Estado Delta Amacuro
Investigación y Postgrado , 2008,
Abstract: the main objectives of this descriptive and ethnographic field research are: to describe the present habitat of a warao community, determine the socio-economic and educational aspects of a sample population and to describe aspects such as: social organization, cosmovision, socio-cultural changes and perspectives for the future, in the framework of the bilingual intercultural education programme offered to the teachers of this ethnic group by the ipr ?el mácaro?. the warao?s are an indigenous community that lives in the orinoco delta. the 73 members of the group of students that are part of this programme were key informants. the data was triangulated by means of participating observation and in-depth interviews. the instruments used for data gathering were: video and photographic cameras, notebooks, gathering of samples of objects commonly used and self-response questionnaires. this project will contribute to the fulfillment of the mission of the university in this area of research as well as to improve the quality of intercultural education.
Publicaciones de la revista Agronomía Mesoamericana durante el periodo 1990-2010: clasificación, temática, países y difusión
Pe?a Navarro,Nelson;
Agronomía Mesoamericana , 2011,
Abstract: publications of the mesoamerican journal of agronomy during the period 1990-2010: classification, thematic, countries and diffusion. the objective of this study was to assess the thematic and sources of the publications in the mesoamerican journal of agronomy during the period 1990-2010. mesoamerican journal of agronomy was created as a publication of the central american cooperative program for the improvement of crops and livestock (pccmca ). from 1990 to date, 629 papers have been published, of which 63% are scientific articles, 26% are technical notes, 8% are analyses and commentaries, while technical information and literature reviews are 2% each. costa rica and mexico are the countries with the largest number of published papers, with 37 and 32% respectively, followed by el salvador, guatemala, honduras and cuba. the principal topics have been corn (24%) and beans (21%), forages (7%), and dairy cattle (4%), while rice, sorghum, weeds and peach palm reached 3% each. in 2010, the journal rejected 20% of all papers submitted for publication. we highlight the distribution of the printed journal to libraries and documentation centers in thirty countries around the world, mainly the continents of america, europa, asia and some caribbean islands.
El lugar sin límites de José Donoso: una re-lectura desde la alegoría de Walter Benjamin
Rodríguez A.,Nelson;
Literatura y lingüística , 2003, DOI: 10.4067/S0716-58112003001400003
Abstract: the following work is a study, that attempts to construct a re-reading to the novel written by josé donoso el lugar sin límites (the place without boundaries), based on the analysis and reflection that the german philosopher walter benjamin develops concerning the problem of allegory. allegory is dealt with in three connotations. the first conceives allegory as (the story) history itself, as "that which happens". the second is a relationship of (the story) history with "what has been", the past that (the story) history has, such as "the ruin". the third is made up by the trauerspiel, which is the staging of (the story) history, the death scene for example. these three elements will allow us to open the re-reading, due to the many carried out, to understand the work of donoso, as (the story) history itself, ours, that of chile's, or any other. the discussion, that we should start from this article is the possibility to understand literature as 'us reading ourselves', from the ruin and the scent of death that life has
Transición de la infancia a la adolescencia: notas para la práctica pediátrica
Vargas,Nelson A.;
Archivos argentinos de pediatr?-a , 2004,
Abstract: the transition from childhood to adolescence is analyzed based on information found in internet, chilean research results obtained in the decades of 1980 and 1990 and personal experience. some guidelines are proposed to make this transition easier and softer as well as to prevent problems or to allow quick and better detection of eventual major crises. emphasis is made on the advantage of taking into account individual general and family contexts and the convenience of preparedness. anticipatory guides for parents and children are outlined as potentially useful tools while some practical management attitudes are suggested for preparation. the importance of good communication and advisable parent's communication styles is emphasized.
170 a?os de la Escuela de Medicina de la Universidad de Chile: su aporte a la salud infantil y del adolescente en Chile
Vargas C.,Nelson A.;
Revista chilena de pediatría , 2003, DOI: 10.4067/S0370-41062003000200001
Abstract: a biomedical and paedriatric literature review was carried out to examine the relationship between the university of chile medical school, founded in 1833, and the first in the country, and the evolution of child and adolescent health during its 170 year history. gradually, the school provided the basis for the university of chile, faculty of medicine. the article highlights some of the important events and persons that made important contributions to the care of children and adolescents in chile
Apoptosis: experiencias en la anatomía patológica experimental
Merino García,Nelson;
Revista Cubana de Investigaciones Biom??dicas , 2001,
Abstract: the effectiviness of the tunel method was evaluated and compared with that of the conventional hematoxylineosin technique. the histopathology of a squamous cell carcinoma was studied by using both techniques and it was observed that the tunel method reduced the apoptosis indices
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