3,062 research outputs found

    El efecto de redundancia en el aprendizaje predictivo humano: Evidencia en contra de una interpretación proposicional.

    Get PDF
    The redundancy effect is the finding of greater learning when an X stimulus is trained in an A+ AX+ blocking procedure, than when a Y stimulus is trained in a BY+ CY- discrimination procedure. These findings are new and theoretically challenging for all conditioning theories that calculate learning based on a common error. For this reason, we alternatively examined the possibility that the phenomenon is the result of a propositional reasoning. In an experiment, we replicated the basic effect and we found out that the addition of instructions on the occurrence of the consequences at a submaximal level does not have a significant impact on the redundancy effect. These findings are discussed with regard to a propositional and associative approach based on the assumption that the experimental stimuli share a common feature.El efecto de redundancia es el hallazgo de un mayor aprendizaje a un estímulo X entrenado en un procedimiento de bloqueo A+ AX+, que a un estímulo Y entrenado en un procedimiento de discriminación BY+ CY-. Estos hallazgos son nuevos y teóricamente desafiantes para todas las teorías del condicionamiento que calculan el aprendizaje en base a un error común. Es por ello que examinamos alternativamente la posibilidad que el fenómeno sea el resultado de un razonamiento proposicional. En un experimento, replicamos el efecto básico y encontramos que la adición de instrucciones sobre la ocurrencia de las consecuencias a un nivel sub-máximo no tiene un efecto significativo sobre el efecto de redundancia. Estos hallazgos son discutidos en relación con una aproximación proposicional y asociativa basada en el supuesto que los estímulos experimentales comparten un elemento común

    Single strand conformation polymorphism (SSCP) detection in six genes in the Portuguese indigenous sheep breed "Churra da Terra Quente"

    Get PDF
    Evaluation of the genetic diversity for six genes in forty animals of the Portuguese indigenous sheep breed (Ovis aries) “Churra da Terra Quente” was done. A non-radioactive method to allow single-strand conformation polymorphism (SSCP) detection was optimised, starting from genomic DNAand PCR amplification of seven fragments: exon 1 of the a-lactalbumin gene; exons 10 and 11 of the as1-casein gene; exon 7 of the b-casein gene; exon 4 of the k-casein gene; exons 4 and 5 of the growth hormone gene and exon 6 of the growth hormone receptor gene. Polymorphisms were detected in five of the PCR products. Only k-casein and growth hormone receptor were monomorphic. a-lactalbumin and as1-casein exons showed three conformational patterns, b-casein and growth hormone exon 4 showed two electrophoretic patterns and growth hormone exon 5 showed five conformational patterns. These data provide evidence that “Churra da Terra Quente” has a high genetic variability, which opens interesting prospects for future selection programs and also for preservation strategies. Also, our data show that PCR-SSCP is an appropriate tool for evaluating genetic variability

    Marketing mix and new product diffusion models

    Get PDF
    In this paper we analyze the relationship between the marketing mix and new product diffusion models. The goal is to obtain a general new product diffusion model that incorporates the classic 4Ps model of the Marketing Mix: Product, Price, Place, Promotion. An empirical study was conducted using mobile broadband adoption data in Japan.info:eu-repo/semantics/publishedVersio

    a before-and-after study and scale-up process in Mozambique

    Get PDF
    BACKGROUND: The universal coverage bed nets campaign is a proven health intervention promoting increased access, ownership, and use of bed nets to reduce malaria burden. This article describes the intervention and implementation strategies that Mozambique carried out recently in order to improve access and increase demand for long-lasting insecticidal nets (LLINs). METHODS: A before-and-after study with a control group was used during Stage I of the implementation process. The following strategies were tested in Stage I: (1) use of coupons during household registration; (2) use of stickers to identify the registered households; (3) new LLIN ascription formula (one LLIN for every two people). In Stage II, the following additional strategies were implemented: (4) mapping and micro-planning; (5) training; and (6) supervision. Odds ratio (OR) and 95% confidence interval (CI) were used to compare and establish differences between intervened and control districts in Stage I. Main outcomes were: percentage of LLINs distributed, percentage of target households benefited. RESULTS: In Stage I, 87.8% (302,648) of planned LLINs were distributed in the intervention districts compared to 77.1% (219,613) in the control districts [OR: 2.14 (95% CI 2.11-2.16)]. Stage I results also showed that 80.6% (110,453) of households received at least one LLIN in the intervention districts compared to 72.8% (87,636) in the control districts [OR: 1.56 (95% CI 1.53-1.59)]. In Stage II, 98.4% (3,536,839) of the allocated LLINs were delivered, covering 98.6% (1,353,827) of the registered households. CONCLUSIONS: Stage I results achieved better LLINs and household coverage in districts with the newly implemented strategies. The results of stage II were also encouraging. Additional strategies adaptation is required for a wide-country LLIN campaignpublishersversionpublishe

    Relative Abundance and Compositional Variation of Silicates, Oxides and Phosphates in the W-Sn-Rich Lodes of the Panasqueira Mine (Portugal): Implications for the Ore-Forming Process

    Get PDF
    Panasqueira is a world-class W-Sn-Cu lode-type deposit located in Portugal. It consists of a dense swarm of subhorizontal quartz lodes criss-crossed by several ENE–WSW and N–S fault zones, bordering Late Variscan granite and hosted in Late Ediacaran—Early Cambrian metasediments. The relative abundance and compositional variation (assessed with EPMA) of the main silicates, oxides and phosphates forming the quartz lodes and their margins were examined, aiming to explore: (i) mineral and geochemical zonation at the mine scale; and (ii) some conclusions on the chemical nature of prevalent fluid inflows and T-conditions of mineral deposition. Quartz lodes nearby or far from the known greisen-granite cupola display significant differences, reflecting multiple fluid influxes of somewhat distinct composition related to various opening and closing events extending for several My, ranging from an early “oxide–silicate stage” (OSS) to a “main sulfide stage” (MSS), and further on to a post-ore carbonate stage (POCS); however, a rejuvenation event occurred after MSS. The onset of OSS was placed at ca. 299 ± 5 Ma and the rejuvenation event at ca. 292 Ma. The OSS was confined to ≈500 ≤ T ≤ 320 °C, following rutile and tourmaline growth under ≈640 ≤ T ≤ 540 °C (depending on aSiO2). The rejuvenation event (≈440–450 °C) preceded a late chlorite growth (≈250–270 °C) and the progression towards POCS.info:eu-repo/semantics/publishedVersio

    TZ- VirtIO: Enabling Standardized Inter-Partition Communication in a Trustzone-Assisted Hypervisor

    Get PDF
    Virtualization technology allows the coexistence and execution of multiple operating systems on top of the same hardware platform. In the embedded systems domain, virtualization has been focused on the isolation of critical requirements like real-time, security and safety from non-critical characteristics. The strict confinement of guest partitions typically provided by virtualization does not suit the modular and inter-cooperative nature of embedded systems. The need for inter-partition communication has been addressed by multiple virtualization solutions, either to enable guest-level device para-virtualization or to ensure increased flexibility regarding cooperative partitions. However, the majority of existing approaches follow an ad hoc approach with limited to none applicability outside their solution's scope. This paper presents TZ-VirtIO, an asynchronous standardized inter-partition communication (IPC) mechanism on top of a TrustZone-assisted dual-OS hypervisor (LTZVisor). The implemented IPC uses the standard VirtIO transport layer. The experiments conducted on a physical platform show a scalable, high-bandwidth and low-overhead solution for both single-core and multi-core architectures.FCT - Fundação para a Ciência e a Tecnologia (UID/CEC/00319/2013

    6β-Chloro-5α-hydr­oxy-20-oxopregnan-3β-yl acetate

    Get PDF
    The title steroid, C23H35ClO4, is a pregnane derivative prepared by ring opening of the corresponding 5α,6α-ep­oxy steroid with BiCl3. There are two symmetry-independent mol­ecules in the asymmetric unit that show no significant differences concerning bond lengths and angles. The conformation of the six-membered rings in both mol­ecules is close to a chair form, while the five-membered ring adopts an envelope conformation. All rings in both mol­ecules are trans-fused. The mol­ecules are held together by an extensive O—H⋯O hydrogen-bonding network
    corecore