272 research outputs found
Skill Acquisition and Transfer in a Simple Algebraic Task
Speelman\u27s (\999) finding that performance of a skill is based to some extent on the conter.t in which it is performed, rather than simply on the acquired skill itself, is not accounted for by the basic skill acquisition theories like ACT -R Theory or Instance Theory. The purpose of the current experiment was to examine whether the degree of change in context influences the degree of reduction in transfer. Forty participants were trained on an algebraic task and then tested in two different transfer conditions. Condition one included one new item and condition two included two new items in the transfer phase. Reaction time, the dependent variable, was measured to find out whether the performance of a learned skill was influenced by the number of new items incorporated into the transfer phase. The results showed that, with an increased number of items changed in the task, the transfer of the previously acquired skill decreased. The findings, along with those of Speelman\u27s (1999), challenge some of the basic underlying assumptions of current theories of skill acquisition and transfer
L'India contemporanea. Dinamiche culturali e politiche, trasformazioni economiche e mutamento sociale
Frutto di uno studio interdisciplinare realizzato da tre grandi centri di ricerca indiani, il volume rende con sapienza la vivacità delle dinamiche sociali e della complessa evoluzione culturale in corso nella società indiana.- Indice #5- Introduzione #9- Correnti culturali e versioni indiane della modernità. Le tradizioni e il futuro della democrazia, Ashis Nandy #13- Caste e classi in India: realtà sociale e rappresentazioni politiche, Dhirubhai L. Sheth #33- Religione e politica in India. Cultura politica, revivalismo, fondamentalismo e secolarismo, Triloki N. Madan #61- Comunitarismo e integrazione nello stato nazionale. Tolleranza e secolarismo, Shail Mayaram #79- Il ruolo delle scuole e delle università nel promuovere una cultura comune e lo sviluppo sociale nelle città e nelle aree rurali, Suma Chitnis #101- I partiti e il processo elettorale in India. Nodi centrali nel dibattito politico corrente, Peter R. de Souza #127- Pluralismo centrale e istituzioni politiche. Lo stato federale indiano e il suo futuro, Ajit Mozoomdar #149- Società civile, movimenti sociali e stato in India: le politiche del cambiamento sociale, Shobha Raghuram #183- Geostrategia e geopolitica dell’India. Sviluppi recenti, sfide contemporanee e prospettive future, Jasjit Singh #209- La demografia e le sue implicazioni economiche, Vishvanath A. Pai Panandiker #235- L’economia dell’India e le sue prospettive, Isher J. Ahluwalia #255- Diseguaglianze nella distribuzione del reddito e del patrimonio in India, Nilakantha Rath #279- Il ruolo dello stato e del mercato nell’economia indiana, Eswaran Sridharan #317- La posizione geoeconomica dell’India. Relazioni internazionali e prospettive dell’integrazione regionale, con particolare riferimento all’ASEAN, Charan D. Wadhva #34
Partial pulmonary embolization disrupts alveolarization in fetal sheep
BACKGROUND: Although bronchopulmonary dysplasia is closely associated with an arrest of alveolar development and pulmonary capillary dysplasia, it is unknown whether these two features are causally related. To investigate the relationship between pulmonary capillaries and alveolar formation, we partially embolized the pulmonary capillary bed. METHODS: Partial pulmonary embolization (PPE) was induced in chronically catheterized fetal sheep by injection of microspheres into the left pulmonary artery for 1 day (1d PPE; 115d gestational age; GA) or 5 days (5d PPE; 110-115d GA). Control fetuses received vehicle injections. Lung morphology, secondary septal crests, elastin, collagen, myofibroblast, PECAM1 and HIF1 alpha abundance and localization were determined histologically. VEGF-A, Flk-1, PDGF-A and PDGF-R alpha mRNA levels were measured using real-time PCR. RESULTS: At 130d GA (term approximately 147d), in embolized regions of the lung the percentage of lung occupied by tissue was increased from 29 +/- 1% in controls to 35 +/- 1% in 1d PPE and 44 +/- 1% in 5d PPE fetuses (p < 0.001). Secondary septal crest density was reduced from 8 +/- 0% in controls to 5 +/- 0% in 1d PPE and 4 +/- 0% in 5d PPE fetuses (p < 0.05), indicating impaired alveolar formation. The deposition of differentiated myofibroblasts (23 +/- 1% vs 28 +/- 1%; p < 0.001) and elastin fibres (3 +/- 0% vs 4 +/- 0%; p < 0.05) were also impaired in embolized lung regions of PPE fetuses compared to controls. PPE did not alter the deposition of collagen or PECAM1. At 116d GA in 5d PPE fetuses, markers of hypoxia indicated that a small and transient hypoxic event had occurred (hypoxia in 6.7 +/- 1.4% of the tissue within embolized regions of 5d PPE fetuses at 116d compared to 0.8 +/- 0.2% of tissue in control regions). There was no change in the proportion of tissue labelled with HIF1 alpha. There was no change in mRNA levels of the angiogenic factors VEGF and Flk-1, although a small increase in PDGF-R alpha expression at 116d GA, from 1.00 +/- 0.12 in control fetuses to 1.61 +/- 0.18 in 5d PPE fetuses may account for impaired differentiation of alveolar myofibroblasts and alveolar development. CONCLUSIONS: PPE impairs alveolarization without adverse systemic effects and is a novel model for investigating the role of pulmonary capillaries and alveolar myofibroblasts in alveolar formation
Search for an invisible in a final state with two muons and missing energy at Belle II
The extension of the standard model predicts the existence
of a lepton-flavor-universality-violating boson that couples only
to the heavier lepton families. We search for such a through its
invisible decay in the process . We use a
sample of electron-positron collisions at a center-of-mass energy of 10.58GeV
collected by the Belle II experiment in 2019-2020, corresponding to an
integrated luminosity of 79.7fb. We find no excess over the expected
standard-model background. We set 90-confidence-level upper limits on the
cross section for this process as well as on the coupling of the model, which
ranges from at low masses to 1 at
masses of 8
Measurement of the branching fraction and asymmetry of decays using pairs in Belle II data
We report measurements of the branching fraction and asymmetry in
decays reconstructed at Belle II in an
electron-positron collision sample containing
pairs. We measure a branching fraction \mathcal{B}(\Bpipi) =
(1.38 \pm 0.27 \pm 0.22) \times 10^{-6} and a asymmetry \Acp(\Bpipi)
= 0.14 \pm 0.46 \pm 0.07, where the first uncertainty is statistical and the
second is systematic
Tests of light-lepton universality in angular asymmetries of decays
We present the first comprehensive tests of light-lepton universality in the
angular distributions of semileptonic \Bz-meson decays to charged spin-1
charmed mesons. We measure five angular-asymmetry observables as functions of
the decay recoil that are sensitive to lepton-universality-violating
contributions. We use events where one neutral \B is fully reconstructed in
\PUpsilonFourS{} \to\B\overline{B} decays in data corresponding to \lumion
integrated luminosity from electron-positron collisions collected with the
\belletwo detector. We find no significant deviation from the standard model
expectations
Measurement of asymmetries and branching-fraction ratios for and with using Belle and Belle II data
We measure asymmetries and branching-fraction ratios for and decays with , where
is a superposition of and . We use the full data set of the
Belle experiment, containing pairs, and data from the
Belle~II experiment, containing pairs, both collected
in electron-positron collisions at the resonance. Our results
provide model-independent information on the unitarity triangle angle .Comment: 26 pages, 8 figure
Observation of decays using the 2019-2022 Belle II data sample
We present a measurement of the branching fractions of four decay modes. The measurement is based on data from
SuperKEKB electron-positron collisions at the resonance
collected with the Belle II detector and corresponding to an integrated
luminosity of . The event yields are extracted from fits
to the distributions of the difference between expected and observed meson
energy to separate signal and background, and are efficiency-corrected as a
function of the invariant mass of the system. We find the branching
fractions to be: where the first uncertainty is statistical and
the second systematic. These results include the first observation of
, , and decays and a significant improvement in the precision
of compared to previous measurements
Search for a resonance in events with the Belle II experiment
We report the first search for a non-standard-model resonance decaying into
pairs in events in
the 3.6-10 GeV/ mass range. We use a 62.8 fb sample of
collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II
experiment at the SuperKEKB collider. The analysis probes three different
models predicting a spin-1 particle coupling only to the heavier lepton
families, a Higgs-like spin-0 particle that couples preferentially to charged
leptons (leptophilic scalar), and an axion-like particle, respectively. We
observe no evidence for a signal and set exclusion limits at 90% confidence
level on the product of cross section and branching fraction into pairs,
ranging from 0.7 fb to 24 fb, and on the couplings of these processes. We
obtain world-leading constraints on the couplings for the leptophilic scalar
model for masses above 6.5 GeV/ and for the axion-like particle model over
the entire mass range
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