630 research outputs found
Concurrent validity of the Alcohol Purchase Task for measuring the reinforcing efficacy of alcohol: an updated systematic review and meta-analysis
Background and aims: An early meta-analysis testing the concurrent validity of the Alcohol Purchase Task (APT), a measure of alcohol''s relative reinforcing value, reported mixed associations, but predated a large number of studies. This systematic review and meta-analysis sought to: (1) estimate the relationships between trait-based alcohol demand indices from the APT and multiple alcohol indicators, (2) test several moderators and (3) analyze small study effects.
Methods: A meta-analysis of 50 cross-sectional studies in four databases (n = 18 466, females = 43.32%). Sex, year of publication, number of APT prices and index transformations (logarithmic, square root or none) were considered as moderators. Small study effects were examined by using the Begg–Mazumdar, Egger''s and Duval & Tweedie''s trim-and-fill tests. Alcohol indicators were quantity of alcohol use, number of heavy drinking episodes, alcohol-related problems and hazardous drinking. APT indices were intensity (i.e. consumption at zero cost), elasticity (i.e. sensitivity to increases in costs), Omax (i.e. maximum expenditure), Pmax (i.e. price associated to Omax) and breakpoint (i.e. price at which consumption ceases).
Results: All alcohol demand indices were significantly associated with all alcohol-related outcomes (r = 0.132–0.494), except Pmax, which was significantly associated with alcohol-related problems only (r = 0.064). The greatest associations were evinced between intensity in relation to alcohol use, hazardous drinking and heavy drinking and between Omax and alcohol use. All the tested moderators emerged as significant moderators. Evidence of small-study effects was limited.
Conclusions: The Alcohol Purchase Task appears to have concurrent validity in alcohol research. Intensity and Omax are the most relevant indices to account for alcohol involvement
The last glacial termination on the eastern flank of the central Patagonian Andes (47ºS)
Few studies have examined in detail the sequence of events during the last glacial termination (T1) in the core sector of the Patagonian Ice Sheet (PIS), the largest ice mass in the Southern Hemisphere outside of Antarctica. Here we report results from Lago Edita (47°8′ S, 72°25′ W, 570 m a.s.l.), a small closed-basin lake located in a valley overridden by eastward-flowing Andean glaciers during the Last Glacial Maximum (LGM). The Lago Edita record shows glaciolacustrine sedimentation until 19 400 yr BP, followed by organic sedimentation in a closed-basin lake and a mosaic of cold-resistant hygrophilous conifers and rainforest trees, along with alpine herbs between 19 400 and 11 000 yr BP. Our data suggest that the PIS retreated at least  ∼  90 km from its LGM limit between  ∼  21 000 and 19 400 yr BP and that scattered, low-density populations of cold-resistant hygrophilous conifers, rainforest trees, high-Andean and steppe herbs thrived east of the Andes during the LGM and T1, implying high precipitation levels and southern westerly wind (SWW) influence at 47° S. The conifer Podocarpus nubigena increased between 14 500 and 13 000 yr BP, suggesting even stronger SWW influence during the Antarctic Cold Reversal, after which it declined and persisted until 11 000 yr BP. Large increases in arboreal pollen at  ∼  13 000 and  ∼  11 000 yr BP led to the establishment of forests near Lago Edita between 10 000 and 9000 yr BP, suggesting a rise in the regional tree line along the eastern Andean slopes driven by warming pulses at  ∼  13 000 and  ∼  11 000 yr BP and a subsequent decline in SWW influence at  ∼  11 000 yr BP. We propose that the PIS imposed a regional cooling signal along its eastern, downwind margin through T1 that lasted until the separation of the northern and southern Patagonian ice fields along the Andes during the Younger Dryas period. We posit that the withdrawal of glacial and associated glaciolacustrine environments through T1 provided a route for the dispersal of hygrophilous trees and herbs from the eastern flank of the central Patagonian Andes, contributing to the afforestation of the western Andean slopes and pacific coasts of central Patagonia during T1.Fil: HenrÃquez, William I.. Victoria University Of Wellington; Nueva ZelandaFil: Villa-Martinez, Rodrigo. Gaia-antártica Universidad de Magallanes; ChileFil: Vilanova, Isabel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: De Pol-Holz, Ricardo. Gaia-antártica Universidad de Magallanes; ChileFil: Moreno, Patricio. Instituto de EcologÃa y Biodiversidad, Departamento de; Chil
Mineral phases in metakaolin-portlandite pastes cured 15 years at 60 °C. New data for scientific advancement
One of the problems addressed by the scientific community in connection with cement matrix hydration is the evolution of hydrated phases under certain, primarily temperature-related, curing conditions. Such conditions are of utmost importance when the cement generates metastable hydrated phases that develop into stable phases, inducing substantial physical-mechanical changes in the matrix. One such instance arises during the pozzolanic reaction between metakaolinite and calcium hydroxide at 60 °C when metastable hexagonal phases co-exist with cubic stable phases. Such processes are well understood in the short and medium term (<5 years). Evolution at longer curing times has not been studied, however. This paper describes the evolution of the initial (stable and metastable) mineral phases in the metakaolinite / Ca(OH) reaction toward a zeolite-like phase after 15 year curing at 60 °C. An understanding of such mineralogical changes is scientifically significant, given their direct impact on the engineering properties of cement-based matricesThe authors thank the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (ref: RTI2018-097074-B-C21/C22
Tilting mutation of weakly symmetric algebras and stable equivalence
We consider tilting mutations of a weakly symmetric algebra at a subset of
simple modules, as recently introduced by T. Aihara. These mutations are
defined as the endomorphism rings of certain tilting complexes of length 1.
Starting from a weakly symmetric algebra A, presented by a quiver with
relations, we give a detailed description of the quiver and relations of the
algebra obtained by mutating at a single loopless vertex of the quiver of A. In
this form the mutation procedure appears similar to, although significantly
more complicated than, the mutation procedure of Derksen, Weyman and Zelevinsky
for quivers with potentials. By definition, weakly symmetric algebras connected
by a sequence of tilting mutations are derived equivalent, and hence stably
equivalent. The second aim of this article is to study these stable
equivalences via a result of Okuyama describing the images of the simple
modules. As an application we answer a question of Asashiba on the derived
Picard groups of a class of self-injective algebras of finite representation
type. We conclude by introducing a mutation procedure for maximal systems of
orthogonal bricks in a triangulated category, which is motivated by the effect
that a tilting mutation has on the set of simple modules in the stable
category.Comment: Description and proof of mutated algebra made more rigorous (Prop.
3.1 and 4.2). Okuyama's Lemma incorporated: Theorem 4.1 is now Corollary 5.1,
and proof is omitted. To appear in Algebras and Representation Theor
The deterioration and environmental impact of binary cements containing thermally activated coal mining waste due to calcium leaching
Calcium-leaching processes can potentially degrade the structure of a concrete matrix. This problem is studied here through the progressive dissolution of Ca2+ in both ordinary Portland cement pastes (C-0) and binary cement blends (C-20) containing 20% thermally Activated Coal Mining Waste (ACMW).1 A series of accelerated tests are conducted that involve the immersion of these cement pastes in a 6 M ammonium nitrate solution at a temperature of 20  C for 7 and for 21 days. A rise in paste porosity was observed, due to increased capillary pore sizes of between 5 and 0.1 μm. In the case of the 20% ACMW pastes (C-20), calcium leaching decreased, probably as a consequence of the pozzolanic effect of the ACMW, while potassium and magnesium leaching increased, due to the presence of the phyllosilicates in the ACMW. The paste compounds most affected by leaching were Ca(OH)2, C6AS3H32, and C4AC¯H12. In general terms, it can be concluded that the incorporation of ACMW into binary cements slightly reduces the calcium leaching phenomena. Concerning the environmental impact assessment, the substitution of 20% OPC by ACMW reduced CO2 emissions by as much as 12% and improved energy efficiency by using approximately 19% fewer fossil resources.This research was developed in the framework of the MATCON Associated Unit (CSICTecnalia,
Madrid, Spain) with the support of the Spanish Ministry of Economy and
Competitiveness (Project Ref. MAT2012-37005-CO3-01/02/03) and the European
Regional Development Fund (MINECO/FEDER) (Project Ref.BIA2015-65558-C3-
1,2,3-R. The authors are also grateful to the Sociedad Anónima Hullera Vasco-Leonesa
and to the Spanish Cement Institute (IECA) for providing us with raw materials
Are protected areas covering important biodiversity sites? An assessment of the nature protection network in Sicily (Italy)
GIS spatial analysis of three indicators (vegetation value, faunal richness and landscape heterogeneity) was used to detect and map High-Value Biodiversity Areas (HVBAs), estimate the coverage of biodiversity in the Sicilian protected areas network, and identify new priority areas that could improve long-term biodiversity conservation outcomes. Findings indicated that only 32% of HVBAs are currently covered by the protected areas network. Hotspot analysis revealed that a modest expansion (less than 1%) in the current extent of protected areas would include a disproportionate amount (56%) of biodiversity hotspots, and identified prioritized candidates HVBAs for designation of new protected areas. © 2018 Elsevier Lt
N-complexes as functors, amplitude cohomology and fusion rules
We consider N-complexes as functors over an appropriate linear category in
order to show first that the Krull-Schmidt Theorem holds, then to prove that
amplitude cohomology only vanishes on injective functors providing a well
defined functor on the stable category. For left truncated N-complexes, we show
that amplitude cohomology discriminates the isomorphism class up to a
projective functor summand. Moreover amplitude cohomology of positive
N-complexes is proved to be isomorphic to an Ext functor of an indecomposable
N-complex inside the abelian functor category. Finally we show that for the
monoidal structure of N-complexes a Clebsch-Gordan formula holds, in other
words the fusion rules for N-complexes can be determined.Comment: Final versio
La improvisación: una alternativa para desarrollar la musicalidad.
El presente trabajo nace de los retos encontrados por tres profesores de música del colegio San Bartolomé La Merced. Tales retos llevan al grupo a cuestionar una serie de hábitos y creencias en torno a los procesos de enseñanza aprendizaje de la música. De esta forma, cuestionan el lugar brindado a los procesos creativos, particularmente la escasa atención brindada a estrategias que inviten a utilizar la música como forma de expresión e interacción con otros.The present work is born from the challenges encountered by three teachers of music of the school San Bartolomé La Merced. Such challenges lead the group to question a series of habits and beliefs about the teaching of music. In this way, they question the place given to creative processes, particularly the careful attention given to strategies that invite the use of music as a form of expression and interaction with others.Magister en EducaciónMaestrÃ
The first Hochschild cohomology group of a schurian cluster-tilted algebra
Given a cluster-tilted algebra B we study its first Hochschild cohomology group HH1(B) with coefficients in the B-B-bimodule B. We find several consequences when B is representation-finite, and also in the case where B is cluster-tilted of type Ã.Fil: Assem, Ibrahim. University of Sherbrooke; CanadáFil: Redondo, Maria Julia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - BahÃa Blanca. Instituto de Matemática BahÃa Blanca. Universidad Nacional del Sur. Departamento de Matemática. Instituto de Matemática BahÃa Blanca; Argentin
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