Agency improves working memory and accelerates visual and attentional processing

ABSTRACTAgency, understood as the ability of an organism to control stimuli onset, modulates perceptual and attentional functions. Since stimulus encoding is an essential component of working memory (WM), we conjectured that the perceptual process’s agency would positively modulate WM. To corroborate this proposition, we tested twenty-five healthy subjects in a modified-Sternberg WM task under three stimuli presentation conditions: an unpredictable presentation of encoding stimulus, self-initiated presentation of the stimulus, and self-initiation presentation with random-delay stimulus onset. Concurrently, we recorded the subjects’ electroencephalographic signals during WM encoding. We found that the self-initiation condition was associated with better WM accuracy, and earlier latencies of N100 and P200 evoked potential components representing visual and attentional processes, respectively. Our work demonstrates that agency enhances WM performance and accelerates early visual and attentional processes deployed during WM encoding. We also found that self-initiation presentation correlates with an increased attentional state compared to the other two conditions, suggesting a role for temporal stimuli predictability. Our study remarks on the relevance of agency in sensory and attentional processing for WM.

Dynamic Behavior to Fatigue Crack Initiation of a Glass/Epoxy Laminate

This paper based to study of the dynamic and fatigue behaviors with numerical and experimental parts of a composite material manufactured by stacking two layers of E-glass fiber in different angle orientations (0°/90°) immersed in polyester resin with total thickness 1.39mm. In Finite Element Analysis (FEA) using ABAQUS was used to evaluate the maximal (displacement, strain and stress) and the natural frequencies (mode shapes) of composite behavior under crack initiation condition. In the experimental part the laminate plate specimen with two layers is tested under one types of cyclic load in fully reversible tensile at (R=0), the fast fracture occur phenomenon and the fatigue life are presented , the fatigue testing exerted in INSTRON 8801 machine.

Improved plantlet regeneration from open-pollinated families of Abies alba trees of Dobroč primeval forest and adjoing managed stand via somatic embryogenesis

Possibility to improve plantlet regeneration from Abies alba Mill. open-pollinated families of 4 trees in Dobroč primeval and 3 trees in managed forest was studied. Immature zygotic embryos were cultured in order to obtain initiation of embryogenic tissue. Totally, three from the families of the managed forest (57%) and two from the primeval families (50%) responded to initiation condition. Initiation frequencies among families ranged in managed forest: 4.5–56.2%, primeval: 5.4–16.8%. Maturation ability was shown by 77.3% of the primeval cell lines, 36.4% cell lines produced cotyledonary somatic embryos. In managed forest, in 62.5% of the cell lines embryo maturation was observed. Cotyledonary embryos developed only in 15% of cell lines. Regenerants were obtained from 9 cell lines of primeval and from 6 cell lines of managed forest. Biochemically, the mature somatic embryos were characterized by the variation in soluble and protein profiles. The corresponding profiles of insoluble proteins exhibited uniform pattern. The variation was characteristic for somatic embryos of individual cell lines rather than for the primeval and managed stands. Enzymatically, no indications were obtained supporting higher metabolic potential of somatic embryos derived from zygotic embryos of silver fir primeval stand than in somatic embryos originating from the trees of managed stand.