185 research outputs found

    Lemur Systematics and Hemoglobin Phylogeny a

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73526/1/j.1749-6632.1988.tb51443.x.pd

    It Works Both Ways: Transfer Difficulties between Manipulatives and Written Subtraction Solutions

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    Three experiments compared performance and transfer among children aged 83-94 months after written or manipulatives instruction on two-digit subtraction. In Experiment 1, all children completed the posttest in a written format, while in Experiment 2, all children took a posttest using manipulatives. Experiment 3 investigated how altered surface features of the blocks affected posttest performance, subtraction strategies and mathematical behaviors. In the first two experiments, children demonstrated performance gains when the posttest format was identical to the instructed format, but failed to demonstrate transfer from the instructed format to an incongruent posttest. Posttest performance in these two experiments provides evidence for bidirectional challenges in transfer between manipulatives and written instruction. In the third experiment, children who learned with standard, unaltered blocks more often used productive problem-solving strategies and engaged in mathematical behaviors significantly more often than children who used blocks with altered surface features. Flexibility and the need to provide explicit links between written and manipulatives instruction are discussed.Fil: David, Uttal H.. Northwestern University; Estados UnidosFil: Amaya, Meredith. Northwestern University; Estados UnidosFil: Maita, María del Rosario. Northwestern University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación; ArgentinaFil: Liu Hand, Linda. Northwestern University; Estados Unidos. University of Iowa; Estados UnidosFil: Cohen, Cheryl. Northwestern University; Estados UnidosFil: O'Doherty, Katherine. Vanderbilt University; Estados UnidosFil: Deloache, Judy. University of Virginia; Estados Unido

    Anti-rat myoglobin antisera in the immunocytochemical diagnosis of rhabdomyosarcomas of rats. Vet

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    Abstract. Anti-rat myoglobin (Mb) was prepared and used in the avidin-biotin-peroxidase complex (ABC) method on paraffin-embedded sections of nine soft tissue tumors (including two rhabdomyosarcomas) of rats. Distribution and nature of the reactive substance to Mb antiserum were compared to those of desmin antiserum. Rat Mb was isolated from the skeletal muscle; monospecificity of the rat antiserum was confirmed by the immunoblotting procedures. The Mb antiserum reacted specifically to normal and neoplastic striated muscle cells. Mb-staining reactions were present diffusely in the cytoplasm, while desmin-staining substances were localized at Z-bands or were diffuse in the cytoplasm as separated aggregates. Reaction to the Mb serum was also detected in cells of thick portions of Henle's loop and distal convoluted tubules

    Black pigmented bacteria in the wall of the periodontal pocket at the beginning and end of the periodontal therapy

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    Objetivo: Determinar la presencia de bacterias negro pigmentadas (BNP) en bolsas periodontales, antes y después de un tratamiento periodontal. Materiales y método: El tipo de estudio es descriptivo. Tiene una muestra de 10 áreas, de 10 pacientes, en la que se identificaron bolsas periodontales. Se tomaron muestras en conos de papel, que luego fueron cultivados en el medio de agar sangre con hemina y vitamina K, incubados. Posteriormente se identificó y contabilizó las co-lonias negro pigmentadas, antes y después del tratamiento periodontal. Resultados: De las muestras examinadas antes del tratamiento, se pudo recuperar BNP en un 60 % de muestras cultivadas, con un rango de presencia de 16 a 312 UFC. De las muestras obtenidas después del tratamiento periodontal, se pudo recuperar en un 50 % de ellas, con un rango de presencia de 5 a 70 UFC. El análisis estadístico demuestra la diferencia significativa de las unidades formadoras de colonias, antes y después de la terapia periodontal. Conclusiones: Se demuestra la presencia de BNP en bolsas periodontales y que estas redu-cen su número, posterior a la terapia periodontal.Objective: Determine the presence of black pigmented bacteria (BNP) in periodontal pockets before and after periodontal treatment. Materials and method: The type of study is descriptive which has a sample of 10 areas, ten patients in which periodontal pockets were identified, samples were taken with paper cones, which were then cultured in blood agar medium with hemin and vitamin K, incubated. Subsequently he identified and counted the black pigmented colonies before and after periodontal treatment. Results: Of the first samples examined before treatment could be recovered BNP 60 % of cultured samples with a range of presence of 16-312 CFU and samples obtained after periodontal treat-ment could be recovered in 50 % of them , with a range of 5 to 70 presence UFC, and this is confirmed by statistical analysis. Conclusions: It is concluded that BNP is present in periodontal pockets and that they reduce their presence, after periodontal therapy

    Thermal expansion, heat capacity and magnetostriction of RAl3_3 (R = Tm, Yb, Lu) single crystals

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    We present thermal expansion and longitudinal magnetostriction data for cubic RAl3 (R = Tm, Yb, Lu) single crystals. The thermal expansion coefficient for YbAl3 is consistent with an intermediate valence of the Yb ion, whereas the data for TmAl3 show crystal electric field contributions and have strong magnetic field dependencies. de Haas-van Alphen-like oscillations were observed in the magnetostriction data of YbAl3 and LuAl3, several new extreme orbits were measured and their effective masses were estimated. Zero and 140 kOe specific heat data taken on both LuAl3 and TmAl3 for T < 200 K allow for the determination of a CEF splitting scheme for TmAl3

    Differential-thermal analysis around and below the critical temperature Tc of various low-Tc superconductors: A comparative study

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    We present specific-heat data on the type-II superconductors V3Si, LuNi2B2C and NbSe2 which were acquired with a low-temperature thermal analysis (DTA) technique. We compare our data with available literature data on these superconductors. In the first part we show that the DTA technique allows for fast measurements while providing a very high resolution on the temperature scale. Sharp features in the specific heat such as at the one at the transition to superconductivity are resolved virtually without instrumental broadening. In the second part we investigate the magnetic-field dependence of the specific heats of V3Si and LuNi2B2C at a fixed temperature T=7.5K to demonstrate that DTA techniques also allow for sufficiently precise measurements of absolute values of cp even in the absence of a sharp phase transition. The corresponding data for V3Si and LuNi2B2C are briefly discussed

    Fibrinogen-to-Albumin Ratio and Blood Urea Nitrogen-to-Albumin Ratio in COVID-19 Patients: A Systematic Review and Meta-Analysis

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    Fibrinogen-to-albumin ratio (FAR) and blood urea nitrogen-to-albumin ratio (BAR) are inflammatory biomarkers that have been associated with clinical outcomes of multiple diseases. The objective of this study is to evaluate the association of these biomarkers with the severity and mortality of COVID-19 patients. A systematic search was performed in five databases. Observational studies that reported the association between FAR and BAR values with the severity and mortality of COVID-19 patients were included. Random-effects models were used for meta-analyses, and effects were expressed as Odds Ratio (OR) and their 95% confidence intervals (CI). Publication bias was assessed using the Begg test, while the quality assessment was assessed using the Newcastle Ottawa Scale. A total of 21 studies (n = 7949) were included. High FAR values were associated with a higher risk of severity (OR: 2.41; 95% CI 1.41–4.12; p < 0.001) and mortality (OR: 2.05; 95% CI 1.66–2.54; p < 0.001). High BAR values were associated with higher risk of mortality (OR: 4.63; 95% CI 2.11–10.15; p < 0.001). However, no statistically significant association was found between BAR values and the risk of severity (OR: 1.16; 95% CI 0.83–1.63; p = 0.38). High FAR and BAR values were associated with poor clinical outcomes.Revisión por pare

    ATP-Dependent Unwinding of U4/U6 snRNAs by the Brr2 Helicase Requires the C Terminus of Prp8

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    The spliceosome is a highly dynamic machine requiring multiple RNA-dependent ATPases of the DExD/H-box family. A fundamental unanswered question is how their activities are regulated. Brr2 function is necessary for unwinding the U4/U6 duplex, a step essential for catalytic activation of the spliceosome. Here we show that Brr2-dependent dissociation of U4/U6 snRNAs in vitro is activated by a fragment from the C terminus of the U5 snRNP protein Prp8. In contrast to its helicase-stimulating activity, this fragment inhibits Brr2 U4/U6-dependent ATPase activity. Notably, U4/U6 unwinding activity is not stimulated by fragments carrying alleles of prp8 that in humans confers an autosomal dominant form of retinitis pigmentosa. Because Brr2 activity must be restricted to prevent premature catalytic activation, our results have important implications for fidelity maintenance in the spliceosome
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