1,122 research outputs found

    Interpreting Force Concept Inventory Scores: NormalizedGain and SAT Scores

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    Preinstruction SAT scores and normalized gains (G) on the force concept inventory (FCI) were examined for individual students in interactive engagement (IE) courses in introductory mechanics at one high school (N=335) and one university (N=292), and strong, positive correlations were found for both populations (r=0.57 and r=0.46, respectively). These correlations are likely due to the importance of cognitive skills and abstract reasoning in learning physics. The larger correlation coefficient for the high school population may be a result of the much shorter time interval between taking the SAT and studying mechanics, because the SAT may provide a more current measure of abilities when high school students begin the study of mechanics than it does for college students, who begin mechanics years after the test is taken. In prior research a strong correlation between FCI G and scores on Lawson\u27s Classroom Test of Scientific Reasoning for students from the same two schools was observed. Our results suggest that, when interpreting class average normalized FCI gains and comparing different classes, it is important to take into account the variation of students\u27 cognitive skills, as measured either by the SAT or by Lawson\u27s test. While Lawson\u27s test is not commonly given to students in most introductory mechanics courses, SAT scores provide a readily available alternative means of taking account of students\u27 reasoning abilities. Knowing the students\u27 cognitive level before instruction also allows one to alter instruction or to use an intervention designed to improve students\u27 cognitive level

    Cardiolipin drives cytochrome c proapoptotic and antiapoptotic actions

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    ""\\"Cytochrome c (cytc) is pivotal in mitochondrial respiration and apoptosis. The heme-Fe-atom of native hexacoordinated horse heart cytc (hhcytc) displays a very low reactivity toward ligands and does not exhibit catalytic properties. However, on interaction with cardiolipin (CL), hhcytc changes its tertiary structure disrupting the heme-Fe-Met80 distal bond. The CL-hhcytc complex displays a very low midpoint potential, out of the range required for its physiological role, binds CO and NO with high affinity, facilitates peroxynitrite isomerization to NO(3)(-), and displays peroxidase activity. As a whole, the CL-hhcytc complex could play either proapoptotic effects, catalyzing lipid peroxidation and the subsequent hhcytc release into the cytoplasm, or antiapoptotic actions, such as scavenging peroxynitrite (i.e., protecting the mitochondrion from reactive nitrogen and oxygen species), and binding of CO and NO (i.e., inhibiting lipid peroxidation and hhcytc traslocation). Here, the CL-driven allosteric modulation of hhcytc properties is reviewed, highlighting proapoptotic and antiapoptotic actions. (C) 2011 IUBMB IUBMB Life, 63(3): 160-165, 2011\\""

    ‘Malvasia nera di Brindisi/Lecce’ grapevine cultivar (Vitis vinifera L.) originated from ‘Negroamaro’ and ‘Malvasia bianca lunga’

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    ‘Malvasia nera di Brindisi’ and ‘Malvasia nera di Lecce’ are two of the few Malvasias with black berries and belong to the Apulian ampelographic assortment (South Italy). Their presumed synonymy has been recently ascertained with SSR markers and therefore these two black 'Malvasias' can be considered as an unique variety. We discovered that this cultivar is the cross between ‘Malvasia bianca lunga’ alias ‘Malvasia del Chianti’ and ‘Negroamaro’ by using 42 nuclear SSR. Both parents belong to the Apulian varietal resources, since centuries. So far, ‘Malvasia nera di Brindisi/Lecce’ origin has been obscure; now we may assert that this cultivar was born right in Apulia. Three sets of chloroplast SSR loci were used to determine the female and the male parent: 6 ccmp loci, already used in previous pedigree studies, 15 ccSSR loci and 2 NTCP loci, derived from tobacco. The second set of loci was sequenced in order to compare the length of the markers with the reference species where they were originally obtained: in 4 cases no microsatellite motives were detected and in other 4 cases the perfect repetition found in tobacco was not maintained in grape. Unfortunately, the three sets of markers failed to show any polymorphism. A detailed comparison of the black Malvasia morphology with its two parents showed a closer similarity to ‘Negroamaro’. Also the anthocyanin profile is in agreement with that of the black parent; its varietal aroma presents interesting levels of free and bound 2-phenylethanol, responsible for rose flavor, and of bound linalool compounds.

    Ibuprofen modulates allosterically NO dissociation from ferrous nitrosylated human serum heme-albumin by binding to three sites

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    Human serum albumin (HSA) is a monomeric allosteric protein. Here, the effect of ibuprofen on denitrosylation kinetics (k(off)) and spectroscopic properties of HSA-heme-Fe(II)-NO is reported. The k(off) value increases from (1.4 +/- 0.2) x 10(-4) s(-1), in the absence of the drug, to (9.5 +/- 1.2) x 10(-3) s(-1), in the presence of 1.0 x 10(-2) M ibuprofen, at pH 7.0 and 10.0 degrees C. From the dependence of k(off) on the drug concentration, values of the dissociation equilibrium constant for ibuprofen binding to to HSA-heme-Fe(II)-NO (K-1 = (3.1 +/- 0.4) x 10(-7) M, K-2= (1.7 +/- 0.2) x 10(-4) M. and K-3 (2.2 +/- .2) x 10(-3) M) were determined. The K-3 value corresponds to the HSA-heme-Fe(II)-NO determined by monitoring drug-dependent absorbance spectroscopic changes (H = (2.6 +/- 0.3) x 10(-3) M). Present data indicate that ibuprofen binds to the FA3-FA4 cleft (Sudlow's site II), to the FA6 site, and possibly to the FA2 pocket, inducing the hexa-coordination of HSA-heme-Fe(II)-NO and triggering the heme-ligand dissociation kinetics. (C) 2009 Elsevier Inc. All rights reserved

    Building typological classification in Switzerland using deep learning methods for seismic assessment

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    Natural disasters, such as earthquakes, have always represented a danger to human life. Seismic risk assessment consists of the evaluation of existing buildings and their expected response in case of an earthquake; the exposure model of buildings plays a key role in risk calculations. With this respect, in recent years, advanced techniques have been developed to speed up and automatize the processes of data acquisition to data interpretation, although it is worth mentioning that the visual survey is essential to train and validate Machine Learning (ML) methods. In the present study, the identification of building types is conducted by exploiting the traditional visual survey to implement a Deep Learning (DL) classification model. As a first step, city mapping schemes are obtained by classifying buildings according to the main features (i.e., construction period and height classes). Then, Random Forest (RF), a supervised learning algorithm, is applied to classify different building types by exploiting all their attributes. The RF model is trained and tested on the cities of Neuchatel and Yverdon-Les-Bains. The decent accuracy of the results encourages the application of the method to different cities, with proper adjustments in datasets, features and algorithms

    Viticultural Climate Indexes and Their Role in The Prediction of Anthocyanins and Other Flavonoids Content in Seedless Table Grapes

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    Background: Viticulture bioclimatic indexes like the Heliothermal Index (HI), Cool Night Index (CI), and Dryness Index (DI), can be used to assess the influence of climate on grapes’ quality. Methods: HI, CI, and DI + total seasonal irrigation were utilized to assess the effect of climate on the flavonoids content and composition of two Vitis vinifera seedless varieties, ‘Summer Royal’ and ‘Crimson Seedless’, both grown in Apulia (Southern Italy). Results: The flavonoids content was significantly affected by variety and climate conditions on the base of HI, CI, and DI + total seasonal irrigation. Factor analysis applied to climate indexes and flavonoids showed that anthocyanins and flavonols were negatively and positively correlated to CI in both varieties, respectively. Additionally, warmer night temperatures determined higher fla-van-3-ols. HI increase promoted anthocyanins, flavonols, and flavan-3-ols content in Crimson Seedless, whilst it induced an opposite trend in Summer Royal. Finally, DI + total seasonal irrigation showed to be positively linked to flavonols content and negatively linked to anthocyanins content just in the case of Crimson Seedless. Significant regression models were also determined between climate indexes and productive parameters (i.e., yield, TSS, TA, pH, bunch, and berry weight). Conclusions: Climate indexes HI, CI, and DI + total seasonal irrigation showed an effect on quality grape parameters like flavonoids and contributed to building predictive models when new climatic zones are going to be evaluated for the production of table grapes

    Images in Christmas Balls

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    We describe light-reflection properties of spherically curved mirrors, like balls in the Christmas tree. In particular, we study the position of the image which is formed somewhere beyond the surface of a spherical mirror, when an eye observes the image of a pointlike light source. The considered problem, originally posed by Abu Ali Hasan Ibn al-Haitham -- alias Alhazen -- more than a millennium ago, turned out to have the now well known analytic solution of a biquadratic equation, being still of great relevance, e.g. for the aberration-free construction of telescopes. We do not attempt to perform an exhaustive survey of the rich historical and engineering literature on the subject, but develop a simple pedagogical approach to the issue, which we believe to be of continuing interest in view of its maltreating in many high-school textbooks.Comment: 13 pages, 7 figures plain LaTeX; Also see http://cft.fis.uc.pt/eef/mirrors.htm, revised version has simplified formulas, more transparent for a wider audience, one reference adde
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