52 research outputs found

    The Developmental Trajectory of the Operational Momentum Effect

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    Mental calculation is thought to be tightly related to visuospatial abilities. One of the strongest evidence for this link is the widely replicated operational momentum (OM) effect: the tendency to overestimate the result of additions and to underestimate the result of subtractions. Although the OM effect has been found in both infants and adults, no study has directly investigated its developmental trajectory until now. However, to fully understand the cognitive mechanisms lying at the core of the OM effect it is important to investigate its developmental dynamics. In the present study, we investigated the development of the OM effect in a group of 162 children from 8 to 12 years old. Participants had to select among five response alternatives the correct result of approximate addition and subtraction problems. Response alternatives were simultaneously presented on the screen at different locations. While no effect was observed for the youngest age group, children aged 9 and older showed a clear OM effect. Interestingly, the OM effect monotonically increased with age. The increase of the OM effect was accompanied by an increase in overall accuracy. That is, while younger children made more and non-systematic errors, older children made less but systematic errors. This monotonous increase of the OM effect with age is not predicted by the compression account (i.e., linear calculation performed on a compressed code). The attentional shift account, however, provides a possible explanation of these results based on the functional relationship between visuospatial attention and mental calculation and on the influence of formal schooling. We propose that the acquisition of arithmetical skills could reinforce the systematic reliance on the spatial mental number line and attentional mechanisms that control the displacement along this metric. Our results provide a step in the understanding of the mechanisms underlying approximate calculation and an important empirical constraint for current accounts on the origin of the OM effect

    Pedometric Tools Applied to Zoning Management of Areas in Brazilian Semiarid Region

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    Brazilian semi-arid region is a recent frontier in the country for agribusiness. The objective of this study is to apply pedometric tools to zoning areas with distinct potential and limitations to agricultural purposes. The research was set in three main steps: (i) to compile a database with all complete profile data collection; (ii) to analyze the vertical variability of soil properties and select a set of soil key properties useful to define the land potential and limitations; and (iii) to classify the area according to potential for agriculture, considering a medium technological level of the farmers. The quantitative methods applied are supported by geographic information systems (GIS) and spatial statistics. The soil data compilation was based on legacy data, with corresponding topographical data and information from remote sensing images of the area. Tree-based and geostatistical algorithms were applied to predict the spatial variability of the soil key properties. The definition of management zones was based on Iso Cluster and Maximum Likelihood Classification tools. The results pointed three different management zones according to risks of salinization and requirements for irrigation control. The approach showed to be a simple and useful way to select and recommend primarily potential areas for agriculture based on soil properties

    Contributions from specific and general factors to unique deficits: two cases of mathematics learning difficulties

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    Mathematics learning difficulties are a highly comorbid and heterogeneous set of disorders linked to several dissociable mechanisms and endophenotypes. Two of these endophenotypes consist of primary deficits in number sense and verbal numerical representations. However, currently acknowledged endophenotypes are underspecified regarding the role of automatic vs. controlled information processing, and their description should be complemented. Two children with specific deficits in number sense and verbal numerical representations and normal or above-normal intelligence and preserved visuospatial cognition illustrate this point. Child H.V. exhibited deficits in number sense and fact retrieval. Child G.A. presented severe deficits in orally presented problems and transcoding tasks. A partial confirmation of the two endophenotypes that relate to the number sense and verbal processing was obtained, but a much more clear differentiation between the deficits presented by H.V. and G.A. can be reached by looking at differential impairments in modes of processing. H.V. is notably competent in the use of controlled processing but has problems with more automatic processes, such as nonsymbolic magnitude processing, speeded counting and fact retrieval. In contrast, G.A. can retrieve facts and process nonsymbolic magnitudes but exhibits severe impairment in recruiting executive functions and the concentration that is necessary to accomplish transcoding tasks and word problem solving. These results indicate that typical endophenotypes might be insufficient to describe accurately the deficits that are observed in children with mathematics learning abilities. However, by incorporating domain-specificity and modes of processing into the assessment of the endophenotypes, individual deficit profiles can be much more accurately described. This process calls for further specification of the endophenotypes in mathematics learning difficulties

    Um sistema nervoso conceitual para o diagnĂłstico neuropsicolĂłgico

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    Although tests are an important aspect of the neuropsychological practice, neuropsychology is not limited to nomothetically validated tests. The objective of this paper is to examine, from the perspective of a “conceptual nervous system”, meta-diagnostic aspects of neuropsychology, which go beyond testing. The nomothetic approach to diagnosis is compared to an idiographic one, in which diagnosis is conceived as hypothesis testing according to information processing models. The construction and use of these models is plausible due to the modular organization of the mental system, evidenced by double-dissociations. In this study, the diagnostic process in neuropsychology is examined, particularly the functional and topographic diagnoses. In most cases, the topographic diagnosis is only virtual, and uses the conceptual nervous system to correlate the observed functional deficit to lesional loci established in the literature. The models of information processing must be anatomically specified, since they will be used to establish structural-functional correlations. The human brain-mind can be seen as a computational system, in which cognition is located between perception (input) and action (output). Mental functions are divided into material (content possessing) and formal (organizers of mental processes). Brain lesions with different causes and locations disrupt these mental functions in different ways. The traditional nomothetic model of neuropsychological diagnosis must be complemented by an idiographic approach, testing hypotheses based on a model of structure-function correlation that is adequate to the anatomo-clinical relations observed in the different lesions. Key words: neuropsychology, structural-functional correlation, cognition.Apesar de a aplicação de testes, a partir de uma perspectiva nomotĂ©tico- nomolĂłgica, constituir um aspecto importante da prĂĄtica neuropsicolĂłgica, a neuropsicologia nĂŁo se resume a esse procedimento. O objetivo deste trabalho Ă© examinar, sob a perspectiva de um “sistema nervoso conceitual”, aspectos metadiagnĂłsticos da neuropsicologia, cujos efeitos ultrapassam o uso de testes normatizados. Ao enfoque nomotĂ©tico Ă© contraposta a perspectiva idiogrĂĄfica, na qual o diagnĂłstico Ă© concebido como teste de hipĂłteses a partir de modelos de processamento de informação. A construção e o uso desses modelos Ă© plausĂ­vel devido Ă  organização modular do sistema mental, evidenciada pelas duplas-dissociaçÔes. Neste trabalho, sĂŁo analisados os processos de diagnĂłstico em neuropsicologia, principalmente o funcional e o topogrĂĄfico. Na maioria das vezes, o diagnĂłstico de localização Ă© virtual, e utiliza o sistema nervoso conceitual para relacionar o dĂ©ficit funcional observado Ă s localizaçÔes lesionais estabelecidas na literatura. Os modelos funcionais de processamento de informação devem ser anatomicamente especificados, para que possam ser usados como base para a correlação estrutura-função. O cĂ©rebro-mente humano pode ser visto como um sistema computacional; neste, a cognição se localiza entre a percepção (input) e a ação (output). As funçÔes mentais sĂŁo classificadas como materiais (com conteĂșdo) e formais (organização dos processos mentais). LesĂ”es encefĂĄlicas com diferentes causas e localizaçÔes alteram essas funçÔes de formas distintas. O modelo nomotĂ©tico tradicional de diagnĂłstico neuropsicolĂłgico deve ser complementado por uma abordagem idiogrĂĄfica, mediante a testagem das hipĂłteses baseadas num modelo de correlação estrutura-função que seja fiel Ă s relaçÔes anĂĄtomo-clĂ­nicas observadas em diferentes lesĂ”es. Palavras-chave: neuropsicologia, correlação estrutura-função, cognição

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Terrestrial behavior in titi monkeys (Callicebus, Cheracebus, and Plecturocebus) : potential correlates, patterns, and differences between genera

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    For arboreal primates, ground use may increase dispersal opportunities, tolerance to habitat change, access to ground-based resources, and resilience to human disturbances, and so has conservation implications. We collated published and unpublished data from 86 studies across 65 localities to assess titi monkey (Callicebinae) terrestriality. We examined whether the frequency of terrestrial activity correlated with study duration (a proxy for sampling effort), rainfall level (a proxy for food availability seasonality), and forest height (a proxy for vertical niche dimension). Terrestrial activity was recorded frequently for Callicebus and Plecturocebus spp., but rarely for Cheracebus spp. Terrestrial resting, anti-predator behavior, geophagy, and playing frequencies in Callicebus and Plecturocebus spp., but feeding and moving differed. Callicebus spp. often ate or searched for new leaves terrestrially. Plecturocebus spp. descended primarily to ingest terrestrial invertebrates and soil. Study duration correlated positively and rainfall level negatively with terrestrial activity. Though differences in sampling effort and methods limited comparisons and interpretation, overall, titi monkeys commonly engaged in a variety of terrestrial activities. Terrestrial behavior in Callicebus and Plecturocebus capacities may bolster resistance to habitat fragmentation. However, it is uncertain if the low frequency of terrestriality recorded for Cheracebus spp. is a genus-specific trait associated with a more basal phylogenetic position, or because studies of this genus occurred in pristine habitats. Observations of terrestrial behavior increased with increasing sampling effort and decreasing food availability. Overall, we found a high frequency of terrestrial behavior in titi monkeys, unlike that observed in other pitheciids

    Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

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    Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt
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