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Search Results: 1 - 10 of 449796 matches for " J.C. "
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A determina??o do boro em plantas pelo método colorimétrico da curcumina
Alcarde, J.C.;
Anais da Escola Superior de Agricultura Luiz de Queiroz , 1969, DOI: 10.1590/S0071-12761969000100004
Abstract: the determination of boron in vegetables by the curcumin colorimetric method is based on the formation of the rosocianin complex in acetic-sulphuric media. in this procedure the reaction takes place in solution at room temperature, needing not to control the temperature at 55 3°c, as with the common method in which the rubrocurcumin complex is formed. an aliquot of the vegetable extract is rendered alkiline by adding a solution of naoh and then dried over a vapor bath. to the residue is added a 0,125% curcumin acetic solution and a (1 + 1) acetic-sulphuric solution. the reaction is completed in 15 minutes. in the application of the method to plant materials analysis, several aspects were studied: interferents and their elimination, the recovery of boron from the ashed samples, the contamination due to filtration through paper filter, and the precision and accuracy of the method. among the normally found elements in vegetable aske, the one interfering were: ca2+, mg2+, fe3+, mn2+ and co2+. they were separated by passing the extract through cation exchange resin. the method, as described, may be considered efficient for the boron determination in vegetables, since it showed good precision and accuracy, coupled with high sensitivity, allowing the determination of as low as 2 ppm of boron in vegetables, within the limits of the least erros.
La revolución de los microarrays en la investigación biosanitaria: tipos de plataformas, usos y perspectivas en oncología
Cigudosa,J.C.;
Anales del Sistema Sanitario de Navarra , 2004, DOI: 10.4321/S1137-66272004000100002
Abstract: through the introduction, use and management of genome-based tools, research into genetic alterations that give rise to diseases as common as cancer has undergone a technical revolution comparable to the introduction of the microscope in laboratories. now, study of the gene-disease relationship is no longer based on analysing a single gene and its effects, but on analysing the behaviour of thousands of genes in a simultaneous form. these systems, generically called matrices, arrays, microarrays or biochips, are changing the way we pose problems and draw conclusions from experiments, since they offer us a complex photo of the genome as a whole. analyses of expression through microarrays of cdni or oligos are now accessible to the spanish scientific community. the results have proved fascinating to researchers since they can be reproduced easily and contribute a great quantity of information on the regulation of the gene expression in normal and pathological conditions.
Interacción entre fármacos y plantas medicinales
Tres,J.C.;
Anales del Sistema Sanitario de Navarra , 2006, DOI: 10.4321/S1137-66272006000300007
Abstract: in recent years there has been a notable increase in the consumption of medicinal plants in spanish society. this might be due to the fact that in some cases they have shown themselves to be efficient in treating certain pathologies and to the erroneous perception that these products are innocuous. medicinal plants behave as authentic medicines since the chemical substances of which they are formed can have a biological activity in humans. for this reason, their joint administration with "conventional medicines" can produce variations in the magnitude of the effect. this type of interaction, just like those produced between two or more medicines, can produce pharmacokinetic mechanisms if they affect the processes of absorption, distribution, metabolism and excretion, or pharmacodynamic mechanisms if they affect the result of the pharmacological action. in the medical literature there are few articles and notifications of cases concerning the adverse effects and interactions that affect medicinal plants, which probably reflects an under-notification of these phenomena. if we add to this the lack of experimental data and controlled studies, perception of their prevalence is difficult or nearly impossible. this article sets out, in an order that will be explained later, the findings of an exhaustive review of the medical literature with the aim of making its existence known to the reader, without going into other considerations, such as the degree of evidence for example, which will be the subject of forthcoming articles.
Biochemical characterization of the GM2 gangliosidosis B1 variant
Tutor, J.C.;
Brazilian Journal of Medical and Biological Research , 2004, DOI: 10.1590/S0100-879X2004000600001
Abstract: the deficiency of the a isoenzyme of ?-hexosaminidase (hex) produced by different mutations of the gene that codes for the a subunit (tay-sachs disease) has two variants with enzymological differences: the b variant consists of the absence of hex a isoenzyme and the b1 variant produces an inactive hex a isoenzyme for the hydrolysis of the gm2 ganglioside and synthetic substrates with negative charge. in contrast to the early childhood form of the b variant, the b1 variant appears at a later clinical stage (3 to 7 years of age) with neurodegenerative symptoms leading to the death of the patient in the second decade of life. the most frequent mutation responsible for the gm2 gangliosidosis b1 variant is r178h, which has a widespread geographic and ethnic distribution. the highest incidence has been described in portugal, which has been suggested as the point of origin of this mutation. biochemical characterization of this lysosomal disease is carried out using negatively charged synthetic a subunit-specific sulfated substrates, since hex a isoenzyme heat-inactivation assays are not applicable. however, the determination of the apparent activation energy of hex using the neutral substrate 3,3'-dichlorophenolsulfonphthaleinyl n-acetyl-?-d-glucosaminide, may offer a valid alternative. the presence of an a subunit in the a? heterodimer hex a means that its activation energy (41.8 kj/mol) is significantly lower than that of the ?? homodimer hex b (75.1 kj/mol); however, as mutation inactivates the a subunit, the hex a of the b1 variant presents an activation energy that is similar to that of the hex b isoenzyme.
OIL GEOCHEMISTRY OF THE PUTUMAYO BASIM
RAMON,J.C.;
CT&F - Ciencia, Tecnología y Futuro , 1996,
Abstract: biomarker fingerprinting of 20 crude oils from putumayo basin, colombia, shows a vertical segregation of oil families. the lower cretaceous reservoirs (caballos and "u" villeta sands) contain oils that come from a mixture of marine and terrestrial organic matter, deposited in a marginal, "oxic" marine setting. the upper cretaceous ("t" and "n" sands) and tertiary reservoirs contain oils with marine algal input deposited in a reducing, carbonate-rich environment. lithology, environmental conditions and organic matter type of source rocks as predicted from oil biomarker differences correspond to organic composition of two cretaceous source rocks. vertical heterogeneity in the oils, even those from single wells, suggests the presence of two isolated petroleum systems. hydrocarbons from lower cretaceous source rocks charged lower cretaceous reservoirs whereas oils from upper cretaceous source rocks charged upper cretaceous and tertiary reservoirs. oil migration from mature source rocks into multiple reservoirs has been stratigraphically updip along the "regional" sandstone units and vertical migration through faults has been limited. biomarker maturity parameters indicate that all oils were generated from early thermal maturity oil window.
Avalia??o de herbicidas aplicados em pré e pós-emergência na cultura da cebola (Allium cepa L.)
Ferreira, J.C.;
Planta Daninha , 1985, DOI: 10.1590/S0100-83581985000100011
Abstract: two field experiments were carried out in grower's fields of the bebedouro irrigation project, in petrolina, pe, in order to study the performance of several herbicides in controlling weeds on transplanted onion crop and the crop tolerance. the treatments were arranged in a randomized complete block design with 3 replications, in a sandy red -yellow latosol, of low clay and organic matter values. in the experiment i, oxadiazon (1.00 kg/h a), pent imethalin (1.25 kg/h a) and napropamide (1.50 kg/ ha) were applied in pre -emergence, two days aft er transplanting; oxyfluorfen (0.24 and 0.48 kg/h a) in early post emergence, ten days after transplanting; oxadiazon (1.00 kg/ha), oxadiazon (1.00 kg/h a) + ammonium sulphat e (5.00 kg/h a), bentazon (0,72 kg/h a), acifluorfen-sodium (0.32 kg/h a), dinoseb acetate (1.50 kg/h a), setoxydim (0.23 kg/ ha), alloxydim -sodium (1.12kg/ha ), diclofop-methyl (0.72 kg/h a) , and bentazon (0.72 kg/ha) + sethoxydim (0.23 kg/h a), 14 days after transplanting. in the experiment ii, oxadiazon (1.00 kg/h a), oxyfluorfen (0.48 and 0.96 kg/h a), and napropamide (1.50 and 3,00 kg/h a) were applied two days after transplanting; oxyf luorfen (0.48 and 0.96 kg/h a), bentazon (0.72 and 1.44 kg/h a), acifluorfen-sodium (0.27 and 0.54 kg/h a), dinoseb acetate (1.50 and 3.00 kg/h a), and bentazon (0.72 kg/h a) + sethoxydim (0.23 kg/h a), 14 days after transplanting. in evaluations made 20 and 34 days after transplanting, respectively in the experiment i and ii, high levels of weed control by oxadiazon and oxyflurfen herbicides were observed. among other treat ments, acifluorfen -sodium was outs tanding in controlling broad leave weeds and sethoxydin, alloxydim-sodium, napropamide, pendimethalin and bentazon + sethoxydim mixture in grass control. in experiment ii, dinoseb and mainly napropamide affected the develop ment of the onion crop and caused yield reductions.
Hete kole op 'n amper koue vuurherd: Oor 'n nuwe bydrae tot die Afrikaanse literêre geskiedskrywing
J.C. Kannemeyer
Tydskrif vir letterkunde , 2004,
Abstract: Hot coals on a near cold fire [Afrikaans] In this article – the text of the annual P.J. Nienaber Memorial Lecture which this year was held at Stellenbosch on 11 March 2004 – the author mentions the important bibliographies and lists of sources which Nienaber published and which served as the necessary data and preliminary spadework for the writing of a history of Afrikaans literature. He outlines the main task of the literary historian and refers to the controversy that arose after the publication of his own work in the 1980s. He mentions other publications in the field of literary history, including Michael Chapman's Southern African Literatures, and in conclusion formulates his own vision of what a history of literature ought to be. Key Words: Nienaber, P.J., Afrikaans literary historiography, Afrikaans literature debates. Hete kole op 'n amper koue vuurherd Oor 'n nuwe bydrae tot die Afrikaanse literêre geskiedskrywing In hierdie artikel – die teks van die jaarlikse P.J. Nienaber-Gedenklesing wat hierdie jaar op 11 Maart 2004 op Stellenbosch gehou is – noem die skrywer die belangrike bibliografie en bronnegidse waarmee Nienaber vir die Afrikaanse literatuurhistorikus die nodige data versamel en voorarbeid verrig het. Hy omskryf die hooftaak van die literêre geskiedskrywer en verwys na die polemiek wat na aanleiding van die publikasie van sy eie werk in die tagtigerjare ontstaan het. Hy verwys ook na ander werk wat intussen op dié gebied gepubliseer is, insluitend Michael Chapman se Southern African Literatures, en formuleer ten slotte sy eie opvatting van hoe 'n literatuurgeskiedenis daar behoort uit te sien. Trefwoorde: Nienaber P.J., Afrikaanse literêre geskiedskrywing, Afrikaanse letterkundige debatte Tydskrif vir letterkunde Vol. 41(2) 2004: 142-156
A REFLECTION OF ADMINISTRATIVE MACHINERIES AND CHALLENGES IN THE MANAGEMENT OF ADULT LITERACY EDUCATION IN NIGERIA
J.C. Ihejirika
Academic Research International , 2013,
Abstract: The focus of this paper was to highlight the challenges associated with promotion of adult literacy education in Nigeria and to examine critically the modalities (structures and strategies) employed by adult literacy institutions in the management of adult literacy programmes. Since 1946, the year of first government mass literacycampaign in the country, Non-Governmental Organizations and some international partners have been playing complementary roles to governmental efforts towards promoting adult literacy education. In addition to well-structured institutional arrangements right from the Federal level to zonal education offices in the 774 localgovernment areas, a good number of administrative strategies including the 1999- launched Universal free Basic Education Programme with its inclusive nature are on ground to reduce the high rate of adult illiteracy in the country. Upon all these, adult illiteracy continues to pose a significant problem in Nigeria. Is it to be understoodthat most of the institutions and personnel charged with the responsibility of planning and organizing adult literacy education lack the expertise and training on how adult literacy programmes should be handled for positive results? However, in the finalanalysis, some identified challenges such as poor conceptualization of adult literacy, lack of political will, inadequate funding, poor professional development, porous literacy environment, etc. which make the practitioners face a Herculean task in performing their duties, must be seriously addressed else, administration and management of adult literacy education will remain a farce in Nigeria.
TEACHING STRATEGIES FOR ADULT LEARNERS: IMPLICATIONS OF LEARNING CHARACTERISTICS FOR EFFECTIVE TEACHINGLEARNING TRANSACTION
J.C. Ihejirika .
Academic Research International , 2013,
Abstract: Adult learners are persons above school age who did not have the opportunity of attending formal school early or might have attended but have educational deficiencies to remedy; hence they voluntarily opt to participate in various learning situations. As they go to learning centres, adults do not leave behind their varied experiences, personal and community problems and needs which they hope to solve with the knowledge and skills acquired through participation in educational programmes. They also possess common learning characteristics, which to some extent; determine the teaching strategies adopted by the instructors to enable learners derive maximum satisfaction of their expectations. This study examined theimplications of such learning characteristics of adult learners and analyzed the appropriate teaching styles and strategies the instructor should employ in each case. Recommendations are made based on the observations of Malcolm Knowles, (1978) a pioneer in the study of adult learning.
Third cumulative index for Koedoe: volumes 35/2-44/1
J.C. Rautenbach
Koedoe : African Protected Area Conservation and Science , 2001, DOI: 10.4102/koedoe.v44i2.179
Abstract: Index to Koedoe: volumes 35/2 - 44/1 Authors 85 Subjects 98 Botany 98 Ecology and behaviour 100 Wildlife conservation & techniques 100 Zoology 102 Invertebrata 102 Pisces 103 Amphibia 103 Reptilia 103 Aves 104 Mammalia 104 Archaeology and History 105 Bibliography 106 Climate 106 Geologyand Pedology 106 Environmental impact on rivers & water quality 106 Check list 107 Issues in conservation 107 Maps 108 Social Science 108 Parks
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