Literacy: A cultural influence on functional left-right differences in the inferior parietal cortex

The current understanding of hemispheric interaction is limited. Functional hemispheric specialization is likely to depend on both genetic and environmental factors. In the present study we investigated the importance of one factor, literacy, for the functional lateralization in the inferior parietal cortex in two independent samples of literate and illiterate subjects. The results show that the illiterate group are consistently more right-lateralized than their literate controls. In contrast, the two groups showed a similar degree of left-right differences in early speech-related regions of the superior temporal cortex. These results provide evidence suggesting that a cultural factor, literacy, influences the functional hemispheric balance in reading and verbal working memory-related regions. In a third sample, we investigated grey and white matter with voxel-based morphometry. The results showed differences between literacy groups in white matter intensities related to the mid-body region of the corpus callosum and the inferior parietal and parietotemporal regions (literate > illiterate). There were no corresponding differences in the grey matter. This suggests that the influence of literacy on brain structure related to reading and verbal working memory is affecting large-scale brain connectivity more than grey matter per se

Scaling relations of branching pulsatile flow

Apparently complex flow structures obey to scaling relations that enable to make it viable the study of their configuration and flow dynamics. This is the case of flow structures that exhibit several branching levels and are thought to perform optimally. Here we present scaling relations of diameters and lengths of branching cylindrical channels with pulsatile flows, and compare them with other relations published in the literature. It is shown that, under constant global volume of the flow tree, and for zero pulse frequency these scaling relations reduce to Murrays's law of consecutive diameters. Optimal scaling depends on pulse frequency, distensibility of the channel walls, and asymmetry of the daughter vessels. In case that in addition to global volume of the flow tree, the pressure head is also kept constant, a similar scaling law of channel lengths emerges that holds together with the law of diameter scaling. The effect of channel distensibility is shown to be somehow important, such that for achieving optimal performance (lowest impedance) channels with lower relative distensibility must have their diameter increased. Results are compared with those of other models for the case of some arteries

Heart rate, arterial distensibility, and optimal performance of the arterial tree

In this study we explore the ability of a previously developed model of pulsatile flow for explaining the observed reduction of arterial distensibility with heart rate. The parameters relevant for the analysis are arterial wall distensibility together with permeability and reflection coefficients of the end capillaries. A non-specific artery and the ensemble of tissues supplied by that artery were considered in the model. The blood current within that artery was equalized to the sum of all micro currents in the tissues supplied by that artery. A formula emerged that relates changes in arterial distensibility with heart rate, and also with some particular aspects of microcirculation. Then, that formula was tested with data of distensibilities of the radial and carotid arteries observed at the heart rates of 63, 90, and 110 b.p.m. The formula correctly predicted the trend of decreased distensibility with heart rate for both arteries. Moreover, due to the fact that the carotid artery supplies the brain, and because the Blood–Brain barrier is highly restrictive to colloids in the blood, for the carotid artery the formula predicted a less marked decrease in distensibility than in the case of the radial artery feeding muscle tissue, which has a greater permeability to colloids, a trend that was confirmed by data. It was found that reduction of arterial distensibility with heart rate was greater in arteries that supply end capillaries with high permeability and low reflection coefficients

Global Electric Circuit research at Graciosa Island (ENA-ARM facility): First year of measurements and ENSO influences

Around 100 years after Carnegie expeditions discovered the Global Electric Circuit, a measuring campaign started at ARM, Eastern North Atlantic facility (Graciosa Island, Azores), meant for the first time to resemble the conditions in which those took place. Here, the first year of measurements (starting April 2015) are analysed and initial results are discussed. The Potential Gradient findings show a deviation from the Carnegie Curves towards inland measurements as a consequence of local aerosol and ion load. The Potential Gradient maxima evolves from 18 UTC (spring/autumn) to 20 UTC (summer), being consistent with the strong 2015 El Nino

Particle deposition in airway bifurcations in different breathing conditions

In this paper, particle deposition in a rigid double bifurcation airway is studied experimentally. The effect of particle size and breathing conditions in the deposition are analyzed. Besides, the effect of airway obstruction (local reduction of airway diameter) that can be originated by some respiratory disorders is also studied. The experiments were performed in conditions of humidity near saturation in order to account for the conditions occurring in the respiratory tree

Stages of behavioral change and positive perception of the environment towards physical activity among urban park users

The objectives of this study were to identify the stages of behavioral change (SBC) towards physical activity (PA) among users of urban parks, to determine the association between socio-demographic and economic variables of users of urban parks in relation to physical activity (PA), and to analyze environmental indicators of the park perceived positively for PA. A total of 218 users of an urban park, who filled out a questionnaire regarding socio-demographic data, SBC and perception of the existing environment, participated in the study. The most prevalent SBC were maintenance (56.6%) and action (21.1%). Most park users (78.7%) presented an active behavior (maintenance + action) towards PA, with this behavior being prevalent among middle-aged individuals (p<0.05). The beauty and geographic location of the park, technological and architectonic factors, some normative policies (public services to the users’ disposition), and values and attitudes were perceived positively for PA, regardless of whether the users regularly performed PA or not. The study suggests that most public park users present an active behavior towards PA, especially middle-aged individuals. In addition, the perception of environmental indicators is positive among physically inactive and active park users, irrespective of SBC

The importance of diffusing capacity as a complementary study to plethysmography in smokers

Rev Port Pneumol. 2007 Nov-Dec;13(6):763-74. [The importance of diffusing capacity as a complementary study to plethysmography in smokers] [Article in Portuguese] Paes Cardoso A, Reis Ferreira JM, Moreira da Silva A. Human Physiology, Porto University, Instituto de Ciências Biomédicas de Abel Salazar, Santo António Hospital. Abstract This study comprised 194 male and female heavy smokers or ex-smokers (>or= 1 pack-year) aged between 20 and 82, whose symptoms varied. Cases were only selected from patients with normal whole-body plethysmography. Subjects with any significant pathology and occupational risk factors were excluded from the study. Varying degrees of symptoms were found and a range of results from normal plethysmography examination, with abnormal levels of alveolar-capillary transfer, determined by the single-breath method to analyse CO (TLCO and TLCO-VA) coefficients. Using the chi-square test for statistical analysis of the sample revealed a significant variation in sensitivity between both parameters (p=0.0001). Possible limitations of using the single-breath method, of were reduced in this study (ventilatory restriction with Vital Capacity <1.5 litres) by the routine plethysmography results seen. Likewise, the presence of alterations in ventilatory distribution was, in principle, minimised by the absence of TLCsb/TLCplet values below 0.85% CONCLUSIONS: Normal plethysmography results in heavy or ex-smokers are not enough to confirm normal respiratory function, as a large percentage of cases present abnormalities in the alveolar-capillary transfer factor for CO. Alveolar limitation was considered not only anatomically, but also from a functional perspective. PMID: 18183328 [PubMed - indexed for MEDLINE

Natural-origin polymers as carriers and scaffolds for biomolecules and cell delivery in tissue engineering applications

The present paper intends to overview a wide range of natural–origin polymers with special focus on proteins and polysaccharides (the systems more inspired on the extracellular matrix) that are being used in research, or might be potentially useful as carriers systems for active biomolecules or as cell carriers with application in the tissue engineering field targeting several biological tissues. The combination of both applications into a single material has proven to be very challenging though. The paper presents also some examples of commercially available natural–origin polymers with applications in research or in clinical use in several applications. As it is recognized, this class of polymers is being widely used due to their similarities with the extracellular matrix, high chemical versatility, typically good biological performance and inherent cellular interaction and, also very significant, the cell or enzyme-controlled degradability. These biocharacteristics classify the natural–origin polymers as one of the most attractive options to be used in the tissue engineering field and drug delivery applications