15,798 research outputs found
Structure of Thin Irreducible Modules of a Q-polynomial Distance-Regular Graph
Let Gamma be a Q-polynomial distance-regular graph with vertex set X,
diameter D geq 3 and adjacency matrix A. Fix x in X and let A*=A*(x) be the
corresponding dual adjacency matrix. Recall that the Terwilliger algebra T=T(x)
is the subalgebra of Mat_X(C) generated by A and A*. Let W denote a thin
irreducible T-module. It is known that the action of A and A* on W induces a
linear algebraic object known as a Leonard pair. Over the past decade, many
results have been obtained concerning Leonard pairs. In this paper, these
results will be applied to obtain a detailed description of W. In particular,
we give a description of W in terms of its intersection numbers, dual
intersection numbers and parameter array. Finally, we apply our results to the
case in which Gamma has q-Racah type or classical parameters
A Child-Directed Music Curriculum in the Montessori Classroom: Results of a Critical Participatory Action Research Study
Maria Montessori strongly advocated for music learning to be fully integrated into the classroom; however, many Montessori classrooms are dominated by materials aimed at developing childrenâs visual sense. The purpose of this critical participatory action research (CPAR) study was to address this perceived learning disparity by developing and implementing a curriculum that is consistent with the Montessori approach, child directed, and focused on sound examination and music learning. We designed six shelf works and offered them, over the course of 6 CPAR cycles, to 20 3- to 6-year-old children attending a Montessori school. Findings from qualitative and quantitative data indicate that the children received the works positively, chose to engage with them, became more confident in their musical tasks over time, showed signs of deep concentration and attention, and demonstrated consistent performance across similar tasks related to perception and cognition. We conclude that the presence of these 6 curricular works began to disrupt the perceived learning disparity we identified; however, more can be done to understand and change the classroom practices that support that disparity
Vector fuzzy dark matter, fifth forces, and binary pulsars
We study the secular effects that an oscillating background ultralight (fuzzy) cosmological vector field has on the dynamics of binary systems; such effects appear when the field and the binary are in resonance. We first consider the gravitational interaction between the field and the systems, and quantify the main differences with an oscillating background scalar field. If the energy density of such a field is sufficiently large, as required if it is supposed to be all of the dark matter, we show that the secular effects could yield potentially observable signatures in high precision time of arrival measurements of binary pulsars. We then analyse the secular effects that arise when the field is directly coupled to the bodies in the binary. We show that this study is particularly relevant for models where fuzzy dark matter mediates a baryonic force B (or B-L, with L the lepton number), due to the stellar amount of nucleons present in the stars. The constraints we obtain from current data are already competitive with (or even more constraining than) laboratory tests of the equivalence principle.Fil: Lopez Nacir, Diana Laura. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de FĂsica de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FĂsica de Buenos Aires; ArgentinaFil: Urban, Federico R.. Czech Academy of Sciences; RepĂșblica Chec
Long Memory and Volatility Clustering: is the empirical evidence consistent across stock markets?
Long memory and volatility clustering are two stylized facts frequently
related to financial markets. Traditionally, these phenomena have been studied
based on conditionally heteroscedastic models like ARCH, GARCH, IGARCH and
FIGARCH, inter alia. One advantage of these models is their ability to capture
nonlinear dynamics. Another interesting manner to study the volatility
phenomena is by using measures based on the concept of entropy. In this paper
we investigate the long memory and volatility clustering for the SP 500, NASDAQ
100 and Stoxx 50 indexes in order to compare the US and European Markets.
Additionally, we compare the results from conditionally heteroscedastic models
with those from the entropy measures. In the latter, we examine Shannon
entropy, Renyi entropy and Tsallis entropy. The results corroborate the
previous evidence of nonlinear dynamics in the time series considered.Comment: 8 pages; 2 figures; paper presented in APFA 6 conferenc
Gender and the Distribution of Wealth in Developing Countries
women, assets, gender inequality, marital regimes, inheritance, land, Latin America, Africa, law
Novel solid-state emissive polymers and polymeric blends from a T-Shaped benzodifuran scaffold: A comparative study
Two novel polyimines were synthesized from a benzodifuran based diamino monomer and two dialdehydes bearing bulky groups and a flexible spacer. The polymers display tuned luminescence performance according to the presence of half-salen groups. The effect of the intramolecular bond on the emission properties were examined. Two model compounds, replicating the same emissive Schiff base cores, were synthetized. From the models, dye-doped blends in the fluorophore/matrix ratio, resembling the polymers, were produced. Amorphous thin films of the covalent polymers and the polymeric blends were obtained by spin-coating technique. The Photoluminescent (PL) response of the different macromolecular systems were qualitatively and quantitatively examined and compared
Investigating the relationship between predictability and imbalance in minimisation : a simulation study
Peer reviewedPublisher PD
Use of pharmacological treatments by a sample of Italian patients affected by alcohol use disorders
Title: USE OF PHARMACOLOGICAL TREATMENTS BY A SAMPLE OF ITALIAN PATIENTS AFFECTED BY ALCOHOL USE DISORDERS
Author name(s): R. Agabio; E.M. Diana; D. Grazzini; R. Pirastu; G.L. Gessa
Institution: Department of Biochemical Sciences, Section of Neuroscience, Preclinical and Clinical Pharmacology, University of Cagliari, Italy
Text
Background: It has often been reported that the majority of patients affected by Alcohol Use Disorders (AUDs) do not receive any pharmacological treatment. This study was aimed at investigating the use of the medications available in Italy (disulfiram, naltrexone, acamprosate, and Îł-hydroxybutyric acid) by a sample of outpatients affected by AUDs.
Methods: Four trained psychologists interviewed outpatients affected by AUDs in an area of Sardinia, Italy, of approximately 550.000 adult inhabitants.
Results: A total sample of 208 outpatients affected by AUDs was interviewed (~1/3 of total outpatients affected by AUDs of that area). Their main features were: 166 males (79.5%); mean age=48.6±0.6 year; duration of AUDs=15.8±0.7 years; number of drinks per drinking days=19.4±1.3; number of criteria of DSM-IV-Tr=5.8±0.1. Before the admission into specific services, 13 patients (6.2%) had already received medication for AUDs; 7 patients (3.4%) had received disulfiram and 6 patients (2.9%) γ-hydroxybutyric acid. Over the same period, 22 patients (10.6%) had already attended self-help groups and 4 patients (1.9%) had received thiamine (Vitamine B1). After the admission into specific medical settings for the treatment of AUDs, 113 patients (54.3%) received medication for AUDs: 58 patients (27.9%) received disulfiram, 65 patients (31.2%) γ-hydroxybutyric acid, 2 patients (1.0%) naltrexone, and 6 patients (2.9%) acamprosate. In the same period, 54 patients (26.0%) frequented self-help associations, and 21 patients (10.1%) received thiamine.
Conclusions: The results of this study confirm that the number of patients who receive a treatment for AUDs continues to be surprisingly low. Despite the long duration and the high level of severity of the AUDs, the majority of patients affected by AUDs did not receive any treatment before their admission in specific medical settings for the treatment of AUDs (10% of patients frequented self-help groups, 6% received a medication for AUDs, and 2% thiamine). After the admission into specific medical settings, the number of patients who received a treatment increased: 26% frequented self-help associations, 54% received a specific medication, and 10% received thiamine. However, approximately half of the patients did not receive any pharmacological treatment even if they frequented medical settings for the treatment of AUDs. Additional work is needed to understand the reasons of such a scarce use of treatments.
Acknowledgements: This study was supported by a grant from Regione Autonoma della Sardegna
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