Enseñanza de Física en el nivel medio : probables estrategias didácticas innovadoras

La dificultad en el aprendizaje de Física es ampliamente conocida en distintos contextos. Ella influye en la eficacia escolar y pone en tela de juicio la calidad educativa de los centros. En este trabajo se describe el estado de avance de una investigación llevada a cabo en IFBA. En la primera etapa de diagnóstico se diseñaron y validaron instrumentos de recolección de información los cuales se aplicaron y están en procesamiento de datos. El producto esperado de esta etapa es una evaluación institucional que evidencie la imagen de la institución respecto a la Física y su enseñanza. En una segunda parte se diseñó e implementó una secuencia didáctica innovadora, sustentada en teorías e investigaciones actuales desarrolladas en el ámbito de didáctica de las ciencias. En ella se está trabajando con dos grupos de estudiantes, uno experimental y otro control. De esta instancia se pretenden obtener conclusiones que evidencien una posible mejora en los resultados del aprendizaje de la Física a partir de modificaciones en las estrategias de enseñanza. La última parte corresponde a la autoevaluación de la propia práctica docente, en esta etapa se validará la secuencia diseñada y su implementación con los instrumentos construidos por el Dr. Godino.A dificuldade na aprendizagem de Física é amplamente conhecida em diferentes contextos. Ela influencia na eficácia escolar e expõe a qualidade educativa dos centros. Neste trabalho se descreve o atual estágio de uma pesquisa que se realiza no IFBA. Na primeira etapa do diagnóstico foram desenhados e validados os instrumentos de recolecção da informação, os quais foram aplicados e estão em processamento de dados. O produto esperado desta etapa é uma avaliação institucional que evidencie a imagem da instituição com respeito à Física y seu ensino. Na segunda parte se elaborou e executou uma sequencia didática inovadora, sustentada em teorias e investigações atuais desenvolvidas no âmbito da didática das ciências. Nela, se está trabalhando com dois grupos de estudantes, um experimental e outro de controle. Desta instancia se pretende obter conclusões que consigam evidenciar uma possível melhora nos resultados da aprendizagem de Física a partir de modificações nas estratégias de ensino. A última parte corresponde à autoavaliação da própria prática docente, e nesta etapa será validada a sequencia desenhada e a sua execução com os instrumentos construídos pelo Dr. Godino da Universidade de Granada

PPAR gamma pro12Ala polymorphism and type 2 diabetes: a study in a spanish cohort

Type 2 diabetes (T2D) is a disease whose occurrence is increasing prevalent in westernized civilizations and is responsible for the proliferation in the morbidity and total mortality of patients with cardiovascular diseases, worldwide. However, the complexity in the treatment and prevention of T2D arises from the intricacy of the many physical and biological factors involved in its etiology. Impaired pathways for insulin signaling have been implicated as one the many factors in the development of T2D Individual peroxisome proliferator-activated receptors (PPARs) have previously exhibited associations with alterations of lipid profiles, fat tissue and T2D and displayed complications derived from high levels of glucose. However, PPARgamma has not yet been associated with the development or developmental pathways of T2D. We performed an observational study a Spanish cohort in order to better understand the association between the SNP PPARgamma polymorphism Pro12Ala in our patients and the incidence of T2D and other cardiovascular complications. We study did not find a statistically significant relationship between the Pro12Ala and T2D development in our cohort, future observations will help us to know the association with vascular disease in patients with T2D

The formation of a nanohybrid shish-kebab (NHSK) structure in melt-processed composites of poly (ethylene terephthalate) (PET) and multi-walled carbon nanotubes (MWCNTs)

The combination of synchrotron Small- and Wide-Angle X-ray scattering (SAXS/WAXS), and thermal analysis was used to follow the evolution of crystalline morphology and crystallization kinetics in a series of melt-processed composites of poly(ethylene terephthalate) (PET) and multiwall carbon nanotubes (MWCNT). The as-extruded PET-MWCNT composites underwent both hot and cold isothermal crystallizations where a final oriented nanohybrid shish-kebab (NHSK) crystalline structure was observed. An oriented NHSK structure was seen to persist even after melting and recrystallization of the composites. From the scattering data, we propose a model whereby the oriented MWCNTs act as heterogeneous nucleation surfaces (shish) and the polymer chains wrap around them and the crystallites (kebabs) grow epitaxially outwards during crystallization. However, depending on crystallization temperature, unoriented crystallites also grow in the polymer matrix, resulting in a combination of a NHSK and lamellar morphology. In contrast, the neat PET homopolymer showed the sporadic nucleation of a classic unoriented lamellar structure under the same isothermal crystallization conditions. These results provide a valuable insight into the distinctive modification of the crystalline morphology of melt-processed polymer-MWCNT composites prior to any secondary processing, having a significant impact on the use of MWCNTs as fillers in the processing and modification of the physical and mechanical properties of engineering polymers

Atopidae (Trilobita) in the upper Marianian (Cambrian Series 2, Stage 4) of Iberia

New atopid trilobites are described from the early Cambrian Cumbres beds and Herreriás shale of northern Huelva Province (Andalusia, Spain) and are dated as middle-late Marianian (Cambrian Series 2, Stage 4). New specimens of Atops calanus Richter and Richter, 1941 are described and the Laurentian species Pseudatops reticulatus (Walcott, 1890b) is recognized for the first time in the Mediterranean subprovince. The associated trilobite assemblage studied herein suggests an age close to the base of Cambrian Stage 4

Impact of minority concentration on fundamental (H)D ICRF heating performance in JET-ILW

ITER will start its operation with non-activated hydrogen and helium plasmas at a reduced magnetic field of B-0 = 2.65 T. In hydrogen plasmas, the two ion cyclotron resonance frequency (ICRF) heating schemes available for central plasma heating (fundamental H majority and 2nd harmonic He-3 minority ICRF heating) are likely to suffer from relatively low RF wave absorption, as suggested by numerical modelling and confirmed by previous JET experiments conducted in conditions similar to those expected in ITER's initial phase. With He-4 plasmas, the commonly adopted fundamental H minority heating scheme will be used and its performance is expected to be much better. However, one important question that remains to be answered is whether increased levels of hydrogen (due to e. g. H pellet injection) jeopardize the high performance usually observed with this heating scheme, in particular in a full-metal environment. Recent JET experiments performed with the ITER-likewall shed some light onto this question and the main results concerning ICRF heating performance in L-mode discharges are summarized here

Análisis de las representaciones icónicas del agua subterránea en los textos de educación secundaria

Las diversas investigaciones didácticas han mostrado que la fase subterránea del ciclo del agua es, junto a la fase área, la peor comprendida por el alumnado e incluso puede pasar desapercibida. Sin embargo, el análisis de las ilustraciones gráficas y otros elementos icónicos presentes en los textos del primer ciclo de educación secundaria obligatoria pone de manifiesto el gran número de conceptos y elementos que se representan en estos materiales curriculares. Con su análisis y trabajo en el aula, los profesores tienen una magnífica oportunidad para favorecer la alfabetización visual del alumnado y eliminar sus errores de comprensión en esta fase del ciclo del agua

Theoretical insight on the treatment of ß-hexachlorocyclohexane waste through alkaline dehydrochlorination

The occurrence of 4.8–7.2 million tons of hexachlorocyclohexane (HCH) isomers stocked in dumpsites around the world constitutes a huge environmental and economical challenge because of their toxicity and persistence. Alkaline treatment of an HCH mixture in a dehydrochlorination reaction is hampered by the low reactivity of the ß-HCH isomer (HCl elimination unavoidably occurring through syn H–C–C–Cl arrangements). More intriguingly, the preferential formation of 1, 2, 4-trichlorobenzene in the ß-HCH dehydrochlorination reaction (despite the larger thermodynamical stability of the 1, 3, 5-isomer) has remained unexplained up to now, though several kinetic studies had been reported. In this paper, we firstly show a detailed Density Functional study on all paths for the hydroxide anion-induced elimination of ß-HCH through a three-stage reaction mechanism (involving two types of reaction intermediates). We have now demonstrated that the first reaction intermediate can follow several alternative paths, the preferred route involving abstraction of the most acidic allylic hydrogen which leads to a second reaction intermediate yielding only 1, 2, 4-trichlorobenzene as the final reaction product. Our theoretical results allow explaining the available experimental data on the ß-HCH dehydrochlorination reaction (rate-determining step, regioselectivity, instability of some reaction intermediates). © 2021, The Author(s)

The use of Barthel index for the assessment of the functional recovery after osteoporotic hip fracture: One year follow-up

The Barthel index evolution was analyzed in a sample of older people with osteoporotic hip fracture in order to verify the influence of comorbidities and cognitive impairment on the physical recovery of those patients, during the first year following the fracture. A prospective observational study was carried out between October 1, 2012 and March 31, 2013. A sample of 247 individuals was initially selected. After a primary revision, 39 participants were excluded (clearly not meeting inclusion criteria, lack of data, or not agree to participate in the study), and finally a total of 208 participants were included in the analysis, 166 women, with an average age of 84.59 years, and 42 men, with an average age of 82.05. 54.80% of all cases were older than 85 years. The mean Barthel index value prior to fracture was 76.63, decreasing to 64.91 at one-year follow-up. Only 22.12% of patients achieved a full recovery for activities of daily living. A statistical analysis was performed by comparing Barthel index recovery depending on the values of Charlson and Pfeiffer indexes, respectively. The mean differences in Barthel index drop between the one-year follow-up and the hospital admission values were found statistical significant (p<0.01). These findings indicate that Charlson and Pfeiffer indexes clearly influence the Barthel index recovery. Low values of Charlson and Pfeiffer indexes resulted in better Barthel index recovery. In conclusion, the Barthel index is a good tool to evaluate the physical recovery after osteoporotic hip fracture

Beyond gold: rediscovering tetrakis-(hydroxymethyl)-phosphonium chloride (THPC) as an effective agent for the synthesis of ultra-small noble metal nanoparticles and Pt-containing nanoalloys

The use of tetrakis-(hydroxymethyl)-phosphonium chloride (THPC) as simultaneous reducing agent and stabilizing ligand has been extended to the single-step synthesis at room temperature of a wide variety of monometallic nanoparticles and bi-/tri- metallic nanoalloys containing noble metals with potential application in catalysis. The colloidal suspensions exhibit mean diameters below 4 nm with narrow size distributions and high stability in aqueous solution for long periods of time

Synthesis of zeolite A using raw kaolin from Ethiopia and its application in removal of Cr(III) from tannery wastewater

BACKGROUND: The commercial production of zeolite A mainly involves costly synthetic chemicals. However, cheaper raw materials such as clay minerals, coal ashes, natural zeolites, solid wastes and industrial sludge have been tested. Based on this, the objective of the present study is synthesis of zeolite A from two sources of raw kaolins (Ansho and Bombowha) from Ethiopia and evaluation of its application in tannery wastewater treatment. RESULTS: The synthesis result indicated high crystallinity (&gt;90%) of zeolite A using Ansho kaolin. Lower grade Bombowha kaolin yielded zeolite A with crystallinity of 80%. In the tannery wastewater treatment study, a real sample having chromium concentration of 2036 mg L-1 was treated, obtaining 99.8% removal and about 200 mg g-1 adsorption capacity of Cr(III) using 100 g L-1 and 5 g L-1 adsorbent dose, respectively. This indicated that the synthesized zeolite A has great potential for Cr(III) removal from tannery wastewater. CONCLUSION: In this study, zeolite A has been synthesized from two sources of kaolin from Ethiopia and has been evaluated in tannery wastewater treatment. The synthesis result indicated the formation of crystals of zeolite A with optimum crystallinity of 91% and the material exhibited chromium removal efficiency of 99.8%