Toward Exact Number: Young Children Use One-to-One Correspondence to Measure Set Identity but Not Numerical Equality

Exact integer concepts are fundamental to a wide array of human activities, but their origins are obscure. Some have proposed that children are endowed with a system of natural number concepts, whereas others have argued that children construct these concepts by mastering verbal counting or other numeric symbols. This debate remains unresolved, because it is difficult to test children’s mastery of the logic of integer concepts without using symbols to enumerate large sets, and the symbols themselves could be a source of difficulty for children. Here, we introduce a new method, focusing on large quantities and avoiding the use of words or other symbols for numbers, to study children’s understanding of an essential property underlying integer concepts: the relation of exact numerical equality. Children aged 32–36 months, who possessed no symbols for exact numbers beyond 4, were given one-to-one correspondence cues to help them track a set of puppets, and their enumeration of the set was assessed by a non-verbal manual search task. Children used one-to-one correspondence relations to reconstruct exact quantities in sets of 5 or 6 objects, as long as the elements forming the sets remained the same individuals. In contrast, they failed to track exact quantities when one element was added, removed, or substituted for another. These results suggest an alternative to both nativist and symbol-based constructivist theories of the development of natural number concepts: Before learning symbols for exact numbers, children have a partial understanding of the properties of exact numbers.Psycholog

Pseudodoping of Metallic Two-Dimensional Materials by The Supporting Substrates

We demonstrate how hybridization between a two-dimensional material and its substrate can lead to an apparent heavy doping, using the example of monolayer TaS$_2$ grown on Au(111). Combining $\textit{ab-initio}$ calculations, scanning tunneling spectroscopy experiments and a generic model, we show that strong changes in Fermi areas can arise with much smaller actual charge transfer. This mechanism, which we refer to as pseudodoping, is a generic effect for metallic two-dimensional materials which are either adsorbed to metallic substrates or embedded in vertical heterostructures. It explains the apparent heavy doping of TaS$_2$ on Au(111) observed in photoemission spectroscopy and spectroscopic signatures in scanning tunneling spectroscopy. Pseudodoping is associated with non-linear energy-dependent shifts of electronic spectra, which our scanning tunneling spectroscopy experiments reveal for clean and defective TaS$_2$ monolayer on Au(111). The influence of pseudodoping on the formation of charge ordered, magnetic, or superconducting states is analyzed.Comment: arXiv admin note: substantial text overlap with arXiv:1609.0022

Inversiones públicas en el Perú (1900-1968): una aproximación cuantitativa

El presente documento se propone reconstruir el patrón de comportamiento de la inversión pública peruana entre 1900 y 1968, a partir de nuevas evidencias empíricas extraídas de los Balances y Cuentas Generales de la República que han permitido elaborar series estadísticas completas del gasto fiscal a lo largo de todo el período examinado. Al proceder de esta manera hemos buscado responder, entre otras, a las siguientes interrogantes: ¿Cuál fue el monto del gasto fiscal total destinado a realizar obras públicas durante los distintos gobiernos que tuvieron bajo su administración el aparato estatal? ¿Qué tipo de obras se ejecutaron y qué orden de prioridades revelaban nuestros gobernantes en sus decisiones de inversión? Y, finalmente, ¿qué grado de autonomía relativa mostró el Estado en su política de inversiones públicas en relación a las presiones ejercidas por los grupos de poder locales

The Aggregation Kinetics of a Simulated Telechelic Polymer

We investigate the aggregation kinetics of a simulated telechelic polymer gel. In the hybrid Molecular Dynamics (MD) / Monte Carlo (MC) algorithm, aggregates of associating end groups form and break according to MC rules, while the position of the polymers in space is dictated by MD. As a result, the aggregate sizes change every time step. In order to describe this aggregation process, we employ master equations. They define changes in the number of aggregates of a certain size in terms of reaction rates. These reaction rates indicate the likelihood that two aggregates combine to form a large one, or that a large aggregate splits into two smaller parts. The reaction rates are obtained from the simulations for a range of temperatures. Our results indicate that the rates are not only temperature dependent, but also a function of the sizes of the aggregates involved in the reaction. Using the measured rates, solutions to the master equations are shown to be stable and in agreement with the aggregate size distribution, as obtained directly from simulation data. Furthermore, we show how temperature induced variations in these rates give rise to the observed changes in the aggregate distribution that characterizes the sol-gel transition.Comment: 9 pages, 10 figure

Crystalline and electronic structure of single-layer TaS2_2

Single-layer TaS$_2$ is epitaxially grown on Au(111) substrates. The resulting two-dimensional crystals adopt the 1H polymorph. The electronic structure is determined by angle-resolved photoemission spectroscopy and found to be in excellent agreement with density functional theory calculations. The single layer TaS$_2$ is found to be strongly n-doped, with a carrier concentration of 0.3(1) extra electrons per unit cell. No superconducting or charge density wave state is observed by scanning tunneling microscopy at temperatures down to 4.7 K.Comment: 6 pages, 4 figure

Gestión pública y políticas alimentarias en el Perú

En primer lugar, Brinda un panorama de la pobreza y de las políticas sociales en el Perú a partir de algunos indicadores básicos que nos permiten ubicar la situación del país en el contexto latinoamericano. Igualmente, son examinadas las principales tendencias de la cooperación internacional, así como el redireccionamiento que están experimentando los flujos de ayuda en el mundo. En segundo lugar, se concentra en definir los principales componentes conceptuales de la cuestión alimentaria, así como también la situación nutricional del país y el marco institucional en el cual opera la intervención estatal. En tercer lugar, se hace una revisión de las teorías más importantes acerca de la lógica que existe en el proceso de formulación e implementación de políticas. Aun cuando se trata de literatura académica concebida para burocracias de países desarrollados, los elementos conceptuales que se desarrollan proporcionan algunas pistas que ayudan a comprender y visualizar mejor las limitaciones e incongruencias que existen en las instituciones públicas peruanas. En cuarto lugar, busca reconstruir cómo funciona la burocracia estatal peruana a partir del análisis del PRONAA y de una “Nueva administración” que, durante parte importante del año 1996, quiso introducir cambios en la misión institucional de este organismo estatal. Al examinar la forma cómo se organizó el proceso de formulación de políticas, cuáles fueron las principales características de la gestión de los programas, el tipo de recursos humanos con los que se contó, los limitados niveles de coordinación, supervisión y evaluación desarrollados, y la relación mantenida con los beneficiarios, la cooperación internacional y las Organizaciones No Gubernamentales, se entenderán mejor las razones que condujeron a su fracaso. Finalmente, intenta llevar a cabo una evaluación del proceso de focalización de la ayuda que se dirige a los comedores populares, así como una evaluación de impacto de un programa específico de la institución cuyo principal objetivo es garantizar el aumento de la seguridad alimentaria de los beneficiarios

Mobilisation Du Foncier Au Profit Des Investissements Immobiliers Publics Dans La Commune D’Abomey-Calavi

Pour faire face à l’évolution démographique et à l’augmentation de la demande de logement dans la ville d’Abomey-Calavi, l’Etat Béninois a initié de nombreux projets de construction de logements économiques au profit des ménages. La présente recherche vise à analyser les stratégies de mobilisation du foncier au profit de ces investissements. La méthodologie de recherche s’est basée sur les recherches documentaires, la collecte de données auprès de 113 personnes par entretien et questionnaire, le traitement de ces données et l’analyse des résultats par le biais du modèle SWOT ou FFOM (Forces, Faiblesses, Opportunités et Menaces).Les résultats obtenus montrent que deux principales stratégies sont utilisées par les autorités pour mobiliser le foncier pour la  construction de logements sociaux.  Il s’agit de la constitution de réserves administratives à l’issue des opérations de lotissement  et de l’expropriation foncière pour cause d’utilité publique.  Au total, 539 réserves administratives ont été constituées dans la Commune d’Abomey-Calavi et environ 3 457 ha de domaines ont été expropriés au profit des programmes immobiliers. Trente-deux (32) logements de type F2, soixante-quinze (75) logements de type F3 et quarante-cinq (45) logements de type F4 ont été construits sur le site de la Zopah à Abomey-Calavi en 2008. De même, il est prévu la construction de 200 logements de type F2, 500 logements de type F3 et 300 logements de type F4 sur un premier site  dans l’Arrondissement de Ouèdo.  Sur un second site du même arrondissement, 8900 logements sont en cours de construction dont 3035 sont pratiquement achevés.  Malgré ces efforts en termes d’investissements,  les ménages font évoquent  des insuffisances qui ne facilitent pas un accès équitable et juste  auxdits logements. . Pour 75% des personnes interrogées, ces logements seraient trop chers ; 20% trouvent que ces logements sont exigus, et 5% trouvent que leurs plans architecturaux ne conviennent pas aux besoins des ménages. Il paraît donc  important que les autorités publiques travaillent davantage à l’ancrage socio-économique de ces logements pour faciliter leur acquisition et leur occupation par les ménages

The IACOB project. IV. New predictions for high-degree non-radial mode instability domains in massive stars and their connection with macroturbulent broadening

Context. Asteroseismology is a powerful tool to access the internal structure of stars. Apart from the important impact of theoretical developments, progress in this field has been commonly associated with the analysis of time-resolved observations. Recently, the so-called macroturbulent broadening has been proposed as a complementary and less expensive way - in terms of observational time - to investigate pulsations in massive stars. Aims: We assess to what extent this ubiquitous non-rotational broadening component which shapes the line profiles of O stars and B supergiants is a spectroscopic signature of pulsation modes driven by a heat mechanism. Methods: We compute stellar main-sequence and post-main-sequence models from 3 to 70 M[SUB]⊙[/SUB] with the ATON stellar evolution code, and determine the instability domains for heat-driven modes for degrees ℓ = 1-20 using the adiabatic and non-adiabatic codes LOSC and MAD. We use the observational material compiled in the framework of the IACOB project to investigate possible correlations between the single snapshot line-broadening properties of a sample of ≈260 O and B-type stars and their location inside or outside the various predicted instability domains. Results: We present an homogeneous prediction for the non-radial instability domains of massive stars for degree ℓ up to 20. We provide a global picture of what to expect from an observational point of view in terms of the frequency range of excited modes, and we investigate the behavior of the instabilities with respect to stellar evolution and the degree of the mode. Furthermore, our pulsational stability analysis, once compared to the empirical results, indicates that stellar oscillations originated by a heat mechanism cannot explain alone the occurrence of the large non-rotational line-broadening component commonly detected in the O star and B supergiant domain. Based on observations made with the Nordic Optical Telescope, operated by NOTSA, and the Mercator Telescope, operated by the Flemish Community, both at the Observatorio del Roque de los Muchachos (La Palma, Spain) of the Instituto de Astrofísica de Canarias