Is Orienting of Attention Selectively Impaired After Sleep Loss? The Role of Disengagement

Research on the effects of sleep deprivation on covert orienting of attention have produced evidence indicating either a negative or a null impact of sleep loss. Moreover, it is still unclear whether, following sleep deprivation, there is a general impairment of orienting processes or a selective one. Aim of the present study is highlighting the effects of sleep deprivation on the three subcomponents of orienting of attention: disengagement, moving and engagement (Posner and Raichle, 1994). The ANT-R (Fan et al., 2009) was administered following two sleep conditions: Baseline - a regular night of uninterrupted sleep, and Deprivation - 24 hours of total sleep deprivation. We have found a significant slowing down of the disengagement component, while engagement and shift components were virtually unaffected by sleep deprivation. Our data show that sleep deprivation selectively affects the three subcomponents underlying covert orienting of attention. Hence, they suggest that performance deficits following sleep curtailment should no longer be accounted for in terms of a general reduction of alertness or global attentional deficits

Cognitive exertion affects the appraisal of one's own and other people's pain.

Correctly evaluating others' pain is a crucial prosocial ability. In both clinical and private settings, caregivers assess their other people's pain, sometimes under the effect of poor sleep and high workload and fatigue. However, the effect played by such cognitive strain in the appraisal of others' pain remains unclear. Fifty participants underwent one of two demanding tasks, involving either working memory (Experiment 1: N-Back task) or cognitive interference (Experiment 2: Stroop task). After each task, participants were exposed to painful laser stimulations at three intensity levels (low, medium, high), or video-clips of patients experiencing three intensity levels of pain (low, medium, high). Participants rated the intensity of each pain event on a visual analogue scale. We found that the two tasks influenced rating of both one's own and others' pain, by decreasing the sensitivity to medium and high events. This was observed either when comparing the demanding condition to a control (Stroop), or when modelling linearly the difficulty/performance of each depleting task (N-Back). We provide converging evidence that cognitive exertion affects the subsequent appraisal of one's own and likewise others' pain

Formación de taumasita en morteros hidráulicos mediante la deposición de SO2 atmosférico

Sulphation of mortars and concretes is a function of diverse environmental factors (SO2 aerosol, temperature, etc) as well as some material characteristics. One of the phases that could be formed as consequence of the sulphation of the hydraulic binder is thaumasite. In this paper different hydraulic mortars have been exposed to laboratory exposure chambers in order to reproduce thaumasite formation due to atmospheric SO2. Under the laboratory exposure conditions, thaumasite was formed in hydraulic lime mortars, and mortars elaborated with ordinary Portland cement as well as mineralized white portland cement. However, thaumasite was not formed in mortars made of lime and pozzolan. The first product formed as a result of the SO2-mortar interaction was gypsum. Gypsum reacted with calcite and C-S-H gel, present in the samples, giving place to thaumasite. Low temperature promotes thaumasite formation.La sulfatación de morteros y hormigones depende de las condiciones ambientales (SO2 aerosol, temperatura, etc.), así como de las características del material. Una de las fases que se puede formar como consecuencia de la sulfatación de los ligantes hidráulicos es la taumasita. En este trabajo se han expuesto diferentes morteros hidráulicos en cámaras de laboratorio con el fin de reproducir la formación de taumasita por efecto del SO2 atmosférico. Bajo las condiciones de laboratorio se formó taumasita en los morteros de cal hidráulica y en los morteros fabricados con cemento portland y cemento blanco mineralizado. Sin embargo, cuando el ligante utilizado en los morteros fue cal y puzolana, no se formó taumasita. El yeso fue el primer producto formado en la interacción entre los morteros y el SO2. A continuación, este yeso reaccionó con la calcita y el gel C-S-H dando lugar a la formación de taumasita. Las bajas temperaturas favorecieron la formación de taumasita

Simulation and theory of abnormal grain growth--anisotropic grain boundary energies and mobilities

Abnormal grain growth has been studied by means of a computer-based Monte Carlo model. This model has previously been shown to reproduce many of the essential features of normal grain growth. The simulations presented in this work are based on a modified model in which two distinct types of grains are present. These two grain types might correspond to two components of different crystallographic orientation, for example. This results in three classes of grain boundaries: 1. (a) between unlike types,2. (b)between grains of the first type and3. (c) between grains of the second type, to which different grain boundary energies or different mobilities can be assigned. Most simulations started with a single grain of the first type embedded in a matrix of grains of the second type. Anisotropie grain boundary energies were modeled by assigning a higher energy to boundaries between like type than to boundaries between grains of unlike type. For this case, abnormal grain growth only occurred for an energy ratio greater than 2 and then wetting of the matrix by the abnormal grain occurred. Anisotropie grain boundary mobilities were modeled by assigning a lower mobility to boundaries between grains of like type than to boundaries between unlike type. For this case the extent of abnormal grain growth varied with the ratio of mobilities and it is tentatively concluded that there is a limiting ratio of size of the abnormal grain relative to the matrix. A simple treatment of anisotropic grain boundary mobility was developed by modifying Hillert's grain growth model [Acta metall. 13, 227 (1965)]. This theoretical treatment also produced a limiting ratio of relative size that is a simple function of the mobility ratio.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28006/1/0000442.pd