Advanced search    

Search: Analytical Chemistry

266 papers found.
Use AND, OR, NOT, +word, -word, "long phrase", (parentheses) to fine-tune your search.

PHENOMENOLOGICAL APPROACHES TO STUDY LEARNING IN THE TERTIARY LEVEL CHEMISTRY LABORATORY

Pedro de Montes de Oca, 2060, San José, Costa Rica ABSTRACT Despite the widespread notion amongst chemistry educators that the laboratory is essential to learn chemistry, it is often a ... a subject of debate for much of college chemistry education history. Already in 1929, Havighurst1 put forth his visionary proposal of shifting away from a curriculum and instructional approach that

Concepción de la identidad química en estudiantes y profesores de química: Parte I - La identidad química como base del concepto macroscópico de sustancia

The value of the concept of substance, both in its theoretical and phenomenological constructions, should be considered in the learning of chemistry. The central idea of chemical identity is defined ...   Chemistry students' and professors' conceptions of chemical identity: Part I – Chemical identity as the basis of the macroscopic concept of substance   Hannah Sevian,¹* Courtney Ngai,¹ Gabriela Szteinberg

Rapid bioerosion in a tropical upwelling coral reef

(>30%) may influence seawater carbon chemistry. This is evident by measurements of an elevated seawater pH (>8.2) and aragonite saturation state (Ωarag >3) at Matapalo Reef during the upwelling period ... , San JoseA? , Costa Rica , 5 Senckenberg am Meer, Wilhelmshaven, Germany , 6 University of Bremen, Faculty of Biology & Chemistry, Marine Ecology Department , Bremen , Germany 1 Editor: Even Moland

Task-based assessment of visualization tools for the comparison of biological taxonomies

Maintenance and curation of large-sized biological taxonomies are complex and laborious activities. Information visualization systems use interactive visual interfaces to facilitate analytical ... visual interfaces to facilitate analytical reasoning on complex information. Several approaches such as treemaps, indented lists, cone trees, radial trees, and many others have been used to visualize and

Relevance of the education: opinions of people graduated from theSchool of chemistry

of Chemistry. The perception of graduates between 2010 and 2014 of the career of Bachelor in Chemistry at University of Costa Rica was assessed by applying a survey where the relevance of thematic ... blocks during vocational training, convenience of present and absent themes in the current curriculum was evaluated and the role of Industrial Chemistry courses, especially professional practice. As a

Nitrogen recycling at the Costa Rican subduction zone: The role of incoming plate structure

compositions with gas chemistry and noble gas compositions of forearc and arc front springs in Costa Rica to show that the structure of the incoming plate has a profound effect on the extent of N subduction into ... this work, we explore forearc regions with new results of N isotope compositions, gas chemistry, and helium isotopes of springs. Costa Rica is the ideal location to perform such a study because in

Chemical and behavioral integration of army ant-associated rove beetles – a comparison between specialists and generalists

is only accomplished by socially integrated species. Considering the interplay between behavior, morphology, and cuticular chemistry, specialists but not generalists have cracked the ants’ social code

Aspects of Scientific Competences Outlined in High School Biology, Physics and Chemistry Syllabus and its Relation with the Scientific and Technological Development Needs of Costa Rica

qualitative research using a hermeneutic study was carried out. Nine participants (three biology teachers, three of physics, and three of chemistry) were selected from three kinds of educational institutions ... Century, Academy of Science, Center of Foreign Trade, INTEL and consultants of Biology, Physics and Chemistry from the Ministry of Public Education. The techniques used to collect information were

Extremely high diversity of sulfate minerals in caves of the Irazú Volcano (Costa Rica) related to crater lake and fumarolic activity

, Costa Rica 4 Red Sismológica Nacional (RSN: UCR-ICE), Apdo. 214-2060, San Pedro , Costa Rica 5 Department of Hydrogeology and Analytical Chemistry, University of Almería , Crta. Sacramento, s/n, 04120 ... procedures (INTE-ISO/IEC17025:2005) at Agrotec Analytical Laboratory (San Jose, Costa Rica). Trace element analyses were measured by inductively coupled plasma optical emission spectrometry (Thermo Trace

Physicochemical and antioxidant composition of fresh peach palm (Bactris gasipaes Kunth) fruits in Costa Rica

. (Ed.). Official methods of analysis of the Association of Official Analytical Chemists. 16th. ed. Gaithersburg: AOAC, 1999. v. 1. [ Links ] Huang, D.; Ou, B.; Hampsch-Woodill, M.; Flanagan, J.; Prior ... /CFRSearch.cfm?fr=101.9>. Accessed on: 6 oct. 2014. [ Links ] Vinson, J.; Su, X.; Zubik, L.; Bose, P. Phenol antioxidant quantity and quality in foods: fruits. ,Journal of Agricultural and Food Chemistry

Practical Issues Concerning the Approval and Use of Biosimilar Drugs for the Treatment of Multiple Sclerosis in Latin America

indicate if changes were made. References 1. Kwon O, Joung J, Park Y, Kim CW, Hong SH. Considerations of critical quality attributes in the analytical comparability assessment of biosimilar products

Comparation of two boron extractant solutions and determination of its content in soil and banana plant

mejorar el límite de detección del método (PerkinElmer 1996). Se analizaron muestras de referencia del programa International Soil Analytical-Exchange (ISE) de Wageningen Evaluating Programs for ... Analytical Laboratories de Holanda (WEPAL) con diferentes contenidos de boro, con el fin de confirmar si la metodología genera resultados comparables con otros laboratorios en el mundo y, de esa forma

Association of moderate-to-vigorous physical activity with neck circumference in eight Latin American countries

]. The minimal amount of accelerometer data that was considered acceptable for analytical purposes was 5 days (including at least one weekend day) with at least 10 h/day of waking wear time. After

Análisis de pintura automotriz mediante espectroscopía Raman para uso forense

, vol. 219, pp. 35-40, 2004. [ Links ] P. L. Stiles, J. A. Dieringer, N. C. Shah y R. P. Van Duyne, “Surface-Enhanced Raman Spectroscopy,” Annual Review of Analytical Chemistry, vol. 1, p. 601-626 ... , “Application of micro-Raman and FT-IR spectroscopy in forensic analysis of automotive topcoats in the Republic of Macedonia,” Macedonian Journal of Chemistry and Chemical Engineering, vol. 27, nº 1, pp. 9-17

The interplay between voluntary food intake, dietary carbohydrate-lipid ratio and nutrient metabolism in an amphibian, (Xenopus laevis)

of the Laboratory of Animal Nutrition, especially Herman De Rycke for the analysis carried out, the Laboratory of Applied and Physical Chemistry, the Laboratory of Animal Nutrition and Animal Product ... Analytical Chemists . 13rd ed. Washington, USA; 1984 . 47. Van Rooijen C , Bosch G , van del Poel A , Wierenga P , Alexander L , Hendriks W. Quantitation of Maillard reaction products in commercially available

Volatile constituents of the oils from Povedadaphne Quadriporata (lauraceae) from "Alberto M. Brenes

were 0.1% (v/w). General analytical procedures GC/FID analysis The oils of P. quadriporata were analyzed by GC/FID using a Shimadzu GC-17 gas chromatograph. The data were obtained on a 5% phenyl

Initial evidence to validate an instructional design-derived evaluation scale in higher education programs

, curricular content, learning activities, educational resources, and the existing evaluation strategy at the Costa Rica Institute of Technology (TEC). Through the use of an analytical and descriptive study, as ... use of an analytical and descriptive study, as well as qualitative and quantitative techniques, a Likert evaluation scale was designed. According to the results, the final version of the instrument

Geosphere-Biosphere Interactions in Bio-Activity Volcanic Lakes: Evidences from Hule and Rìo Cuarto (Costa Rica)

phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes ... . This paper presents the geochemical (water and dissolved gas chemistry) and microbiological results obtained from samples collected in 2010 during the 7th Workshop of the Commission on Volcanic Lakes

Agroquímicos y Sufrimiento Ambiental: Reflexiones desde las Ciencias Sociales

banana workers who have been affected by the use of Nemagon (DBCP). The article suggests some analytical perspectives to recognize the contributions from social science to understand the use and

Pesticides and Environmental Suffering: Perspectives from the Social Sciences

banana workers who have been affected by the use of Nemagon (DBCP). The article suggests some analytical perspectives to recognize the contributions from social science to understand the use and