Analysis of relations between epistemological beliefs about mathematics and academic performance

Resumen: La investigación toma como referencia el Paradigma Multidimensional propuesto por Marlene Schommer y colaboradores, para determinar las dimensiones de creencias epistemológicas sobre la Matemática que se relacionan con el rendimiento académico de esta asignatura. Participaron 522 alumnos de secundaria básica de la provincia de Villa Clara. Se constató que los estudiantes poseen creencias poco productivas para el aprendizaje de esta ciencia afectando los resultados docentes, así por ejemplo: cuando creen en la simplicidad del conocimiento matemático, en la presencia de una autoridad como fuente en la cual radica la información, que no son capaces de aprenderla de manera autodeterminada; que el aprendizaje de la Matemática no requiere del esfuerzo personal, sino que es una habilidad que se posee al nacer peor es su rendimiento. Las correlaciones positivas entre el rendimiento y la dimensión Conocimiento relativo indican que cuando los alumnos creen que el conocimiento matemático es relativo obtienen mejores resultados. Analysis of relations between epistemological beliefs about mathematics and academic performance Abstract:The research draws on the Multidimensional Paradigm proposed by Marlene Schommer et al, to determine the dimensions of epistemological beliefs about mathematics that relate to the achievement of this subject. 522 students attended junior high school in the province of Villa Clara. It was found that students have little productive beliefs for learning this science affecting learning outcomes, so for example, when they believe in the simplicity of mathematical knowledge, in the presence of an authority as a source in which lies the information not they are able to learn selfdetermined way; learning of mathematics does not require personal effort, but it is a skill that has at birth worse performance. Positive correlations between performance and relative dimension Knowledge indicate that when students believe that mathematical knowledge is relative get better results.</jats:p

Transport of persistent organic pollutants across the human placenta

Environment International 65, 107-115 (2014

Ruthenium(II) Picolyl-NHC Complexes: Synthesis, Characterization, and Catalytic Activity in Amine N‑alkylation and Transfer Hydrogenation Reactions

Ruthenium(II) p-cymene complexes with picolylfunctionalized N-heterocyclic carbenes [(η6-p-cymene)Ru(L)(Cl)]- [PF6] (L = 3-methyl-1-(2-picolyl)imidazol-2-ylidene (1a), 3- isopropyl-1-(2-picolyl)imidazol-2-ylidene (1b), 3,4,5-trimethyl- 1-(2-picolyl)imidazol-2-ylidene (1c), 3-mesityl-1-(2-picolyl)- imidazol-2-ylidene (1d), 3-methyl-1-(2-picolyl)benzoimidazol- 2-ylidene (1e), 3-methyl-1-(2-picolyl)-4,5-dichloroimidazol-2- ylidene (1f), 3-phenyl-1-(2-picolyl)imidazol-2-ylidene (1g)) have been synthesized and characterized. Compounds 1a−g were recrystallized, and X-ray crystal structures are reported for 1a,f. Furthermore, compounds 1a−f show catalytic activity in transfer hydrogenation of ketones and N-alkylation of amines. Notably, complexes 1a,c,f were found to be very efficient and versatile catalysts toward transfer hydrogenation of a wide range of ketones and imines in addition to N-alkylation of several amines

Picolyl−NHC Hydrotris(pyrazolyl)borate Ruthenium(II) Complexes: Synthesis, Characterization, and Reactivity with Small Molecules

Ruthenium(II) hydrotris(pyrazolyl)borate chloro complexes bearing picolyl-functionalized N-heterocyclic carbenes [TpRu- (κ2-C,N-picolyl-RI)Cl] (picolyl-MeI = 3-methyl-1-(2-picolyl)imidazol-2- ylidene) (1a), picolyl-iPrI = 3-isopropyl-1-(2-picolyl)imidazol-2-ylidene (1b), picolyl-Me45DClI = 3-methyl-1-(2-picolyl)-4,5-dichloroimidazol- 2-ylidene (1c), picolyl-PhI = 3-phenyl-1-(2-picolyl)imidazol-2-ylidene (1d), picolyl-MeBI = 3-methyl-1-(2-picolyl)benzoimidazol-2-ylidene (1e)) have been synthesized and characterized. Furthermore, cationic carbonyl derivatives 2a−e have been prepared, characterized, and used to study the donor properties of the picolylcarbene ligands (picolyl-RI) via infrared spectroscopy. Also, the reactivity of the 16-electron species [TpRu(κ2-C,N-picolyl-RI)]+, in situ generated using NaBArF 4 (ArF = 3,5-bis(trifluoromethyl)phenyl) as a halide scavenger, toward N2, CH3CN, H2, CH2CH2, S8, and O2 was studied indicating a strong influence of the NHC wingtip and backbone substituents in the product distribution. The crystal structures of [TpRu(κ2- C,N-picolyl-iPrI)Cl] (1b), [TpRu(κ2-C,N-picolyl-MeI)CO][BArF 4] (2a), [TpRu(κ2-C,N-picolyl-PhI)CO][BArF 4] (2d), [{TpRu(κ2- C,N-picolyl-MeI}2(μ-N2)][BArF 4]2 (3′a), [{TpRu(κ2-C,N-picolyl-PhI)}2(μ-N2)][BArF 4]2 (3′d), [TpRu(κ2-C,N-picolyl-iPrI)(η2- CH2CH2)][BArF 4] (5b), and [{TpRu(κ2-C,N-picolyl-MeI)}2(μ-S2)][BArF 4]2 (6) are reported

Long term consumption of thiamethoxam coated seeds causes multilevel effects to the passerine Agelaiodes badius

Presentación en diapositivasBirds and pesticide treated seeds Birds and pesticide treated seedsBirds and pesticide treated seeds Birds and pesticide treated seedsInstituto de Recursos BiológicosFil: Poliserpi, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina.Fil: Fernández-Vizcaino, E. CSIC. Instituto de Investigación de Recursos Cinegéticos (IREC) SCIC-UCLM; EspañaFil: Ruíz de Arcaute, C. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Soloneski, S. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brodeur, Julie Celine. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina