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Abstract : An Analytical Solution to Heat Equation
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Abstract: The present paper explores theoretical aspects of solving the heat equation in the monodimensional case. The proposed study method is the variables separation method, finding thus an original solution, which is compared with the numerical solution obtained by finite difference method. Keywords: Heat equation, non-stationary regime, variables separation method, finite difference method.Download Full Article |
Abstract : Neglect is a Spatial Failure of Alerting Mechanisms Required for Awareness: An ERP Study
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Abstract: In the present study, we describe a group of right brain-damaged (RBD) patients with neglect or extinction, most of them affected in all three (visual, auditory, somatosensory) modalities studied. We applied event-related potential (ERP) analysis to reveal the neural mechanisms underlying hemispatial neglect. ERPs to stimuli of all three modalities were determined for the patients with neglect/extinction at (sub)acute phase, and 3 and 12 months post-stroke. Our results demonstrated that N1 deflections in ERPs, reflecting fronto-parietal alerting mechanisms, were absent or diminished/delayed in neglect, and the waves became normalized with recovery from neglect. In somatosensory ERPs, similar changes were evident also in P1 deflections preceding the N1, reflecting activation of the secondary somatosensory cortex (SII). We also demonstrated somatosensory ERPs of some of our patients who showed different responses elicited by low intensity electrical stimulation of the median nerve at the wrist depending on the location of the hands either in uncrossed anatomical position or crossed over the body midline to the other hemispace. Our results indicate that there are cases among patients with hemispatial neglect who do indeed show emergence or increment of responses to left-hand stimulation when the arm is crossed to the right hemispace. Therefore, we propose that the mechanism underlying hemispatial neglect is the disruption of the flow of (location related) sensory information to awareness at the level of multimodal alerting mechanisms. Keywords: Neglect, alerting, awareness, event-related potential, recovery, space. |
Abstract : Land Cover Dynamics in Beni Chougrane Mountains, North West of Algeria, Using Remote Sensing
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Abstract: Land cover change is the result of complex interactions between social and environmental systems, systems that evolve over time. While climate and biophysical phenomena have long been the main drivers of changes in land surfaces, the human is now behind most of the changes affecting terrestrial ecosystems. The main objective of this work is to show the characterization and monitoring of land cover change in semi-arid Mediterranean area. The changes in agro-forest area which is a land use mode in the mountains of Beni-Chougrane at local scale. We used Support Vector Machines method for classification of Landsat TM image, and change detection technique to analyze change of land cover types by comparing the satellite observations of Landsat TM from 1984 to 2009. Our analysis showed that proportion of forest cover decreased from 41% in 1984 to 14% in 2009 that from approximately 190 hectares/year and agriculture land from 18 % to 1.5 %. The results showed that all land cover and lad use area have experienced structural changes in it's globally, Intensive regression of woody natural vegetation imposed by fires and unsustainable use of resources, a remarkable decline in land occupied by agriculture. Suggesting an immediate response to a policy based on priorities for the preservation, protection, development and rational use of land areas. Keywords: Remote sensing, change detection, Landsat, anthropogenic, Beni-Chougrane. Download Full Article |
Abstract : Autonomic Dysfunction in Asian Indian T2DM Patients is Related to Body Fat Content Instead of Insulin Resistance: A DEXA Study
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Abstract: Aim: To study autonomic dysfunction in Asian Indian T2DM patients by heart rate variability and it's relation with body fat content, distribution and insulin resistance. Subjects and Methods: Subjects: 33 T2DM patients aged (46.96 ± 8.90 yrs), and 33 healthy controls aged (44.08 ± 9.15 yrs). Methods: Short-term heart rate variability (HRV) was measured by impedance plethysmograph recording of pulse wave in distal superficial arteries. Time domain and Frequency domain analysis of HRV was carried out. Time domain parameters (SDNN, rMSSD, pNN50) and frequency domain parameters (Total Power, LF power, HF Power, LF (nu), HF (nu), LF/HF Ratio) were determined. Body fat content and distribution was estimated by (DEXA). Insulin Resistance was assessed by HOMA-R. Student t test was used for comparison of parameters in two groups. Multiple regression was used to find out relation between parameters of adiposity and HRV. Results: Parameters rMSSD, pNN50, Total power, LF Power, HF Power were significantly lower in diabetics. Total power showed negative correlation with BMI and truncal fat (r=-.43; p<. 05) and (r=-.41; p<. 05) respectively. Frequency domain parameter HF (ms2) showed negative correlation with BMI and trunk fat (gm %) (r= -.47; p<. 05) and (r=-.40; p<. 05) respectively. HF (nu) was negatively correlated with BMI (r=-.43; p<. 05) whereas positive correlation was observed between LF (nu) and BMI (r=. 40; p<. 05). Conclusion: T2DM is associated with overall reduction in autonomic activity however, body fat content influences relative modulation of sympathetic and parasympathetic activity among diabetics but not among controls. Contrary to most previous reports, insulin resistance as well as W: H ratio had no influences on autonomic activity. Keywords: T2DM, Autonomic Imbalance, Insulin Resistance, Body Fat Distribution.Download Full Article |
