An integrated brain-behavior model for working memory.

Working memory (WM) is a central construct in cognitive neuroscience because it comprises mechanisms of active information maintenance and cognitive control that underpin most complex cognitive behavior. Individual variation in WM has been associated with multiple behavioral and health features including demographic characteristics, cognitive and physical traits and lifestyle choices. In this context, we used sparse canonical correlation analyses (sCCAs) to determine the covariation between brain imaging metrics of WM-network activation and connectivity and nonimaging measures relating to sensorimotor processing, affective and nonaffective cognition, mental health and personality, physical health and lifestyle choices derived from 823 healthy participants derived from the Human Connectome Project. We conducted sCCAs at two levels: a global level, testing the overall association between the entire imaging and behavioral-health data sets; and a modular level, testing associations between subsets of the two data sets. The behavioral-health and neuroimaging data sets showed significant interdependency. Variables with positive correlation to the neuroimaging variate represented higher physical endurance and fluid intelligence as well as better function in multiple higher-order cognitive domains. Negatively correlated variables represented indicators of suboptimal cardiovascular and metabolic control and lifestyle choices such as alcohol and nicotine use. These results underscore the importance of accounting for behavioral-health factors in neuroimaging studies of WM and provide a neuroscience-informed framework for personalized and public health interventions to promote and maintain the integrity of the WM network

Dynamical Effects from Asteroid Belts for Planetary Systems

The orbital evolution and stability of planetary systems with interaction from the belts is studied using the standard phase-plane analysis. In addition to the fixed point which corresponds to the Keplerian orbit, there are other fixed points around the inner and outer edges of the belt. Our results show that for the planets, the probability to move stably around the inner edge is larger than the one to move around the outer edge. It is also interesting that there is a limit cycle of semi-attractor for a particular case. Applying our results to the Solar System, we find that our results could provide a natural mechanism to do the orbit rearrangement for the larger Kuiper Belt Objects and thus successfully explain the absence of these objects beyond 50 AU.Comment: accepted by International Journal of Bifurcation and Chaos in Aug. 2003, AAS Latex, 27 pages with 6 color figure

Dent–Wrong disease and other rare causes of the Fanconi syndrome

Dent–Wrong disease, an X-linked recessive disorder of the proximal tubules, presents with hypercalciuria, nephrocalcinosis, nephrolithiasis, renal insufficiency, low-molecular-weight proteinuria, rickets and/or osteomalacia. Dent and Friedman initially characterized the disorder in 1964 following studies of two patients with rickets who presented with hypercalciuria, hyperphosphaturia, proteinuria and aminoaciduria. Since then, extensive investigation identified two genetic mutations (CLCN5 and OCRL1) to be associated with Dent–Wrong disease. Clinical features supported by laboratory findings consistent with proximal tubule dysfunction help diagnose Dent–Wrong disease. Genetic analysis supports the diagnosis; however, these two genes can be normal in a small subset of patients. The differential diagnosis includes other forms of the Fanconi syndrome, which can be hereditary or acquired (e.g. those related to exposure to exogenous substances). Treatment is supportive with special attention to the prevention of nephrolithiasis and treatment of hypercalciuria. We review the rare forms of Fanconi syndrome with special attention to Dent–Wrong disease

Time Domain Analysis of Sound Signals for Bearing Damage Identification

Time domain analysis requires less computational time compared to the frequency domain. Analysis is performed directly on the signal without any conversion at all. This paper describes high-frequency signal analysis on sound produced by rotated bearing. Three bearing conditions - normal, damaged, and badly damaged - was chosen to obtain the characteristics of high frequency sound. From the entire spectrum of the recorded sound, the higher frequency range looks very different for the three conditions bearing. Phisically, more damage rotated bearing, the disturbance sound heard more loudly. Bearings were rotated at various rpm, from low to high, to ensure the similarities and differences in characteristics. Average energy and standard deviation were calculated as bearing damage indication

Tribological behaviour of refined bleached and deodorized palm olein in different loads using a four-ball tribotester

AbstractVegetable oil is one of the bio-oils that have been promoted to replace petroleum-based products due to its eco- friendly characteristics. Palm oil has high productivity rate, and so it could fulfil the demand for a bio-lubricant. In this paper, the influence of the normal load on friction and wear performance were investigated for a RBD palm olein and compared with paraffinic mineral oil using four-ball tribotester. The normal load was varied from 30 kg to 60 kg. All experimental works were conforming to ASTM D 4172. The results exhibited that the RBD palm olein has lower coefficient of friction compared to paraffinic mineral oil. However, the wear scar of ball bearings lubricated with RBD palm olein showed larger diameter compared to paraffinic mineral oil. As a conclusion, RBD palm olein has better performance compared to paraffinic mineral oil in terms of capability to reduce friction

The nature of the normal form map for soft impacting systems

Soft impacting mechanical systems-where the impacting surface is cushioned with a spring-damper support-are common in engineering. Mathematically such systems come under the description of switching dynamical systems, where the dynamics toggle between two (or more) sets of differential equations, determined by switching conditions. It has been shown that the Poincare map of such a system would have a power of 1/2 (the so-called square-root singularity) if the vector fields at the two sides of the switching manifold differ, and a power of 3/2 if they are the same. These results were obtained by concentrating on the leading order terms in a Taylor expansion of the zero-time discontinuity map, and are true in the immediate neighbourhood of a grazing orbit. In this paper we investigate how the character of the two-dimensional map changes over a large parameter range as the system is driven from a non-impacting orbit to an impacting orbit. This study leads to vital conclusions regarding the character of the normal form of the map not only in the immediate vicinity of the grazing orbit, but also away from it, as dependent on the system parameters. We obtain these characteristics by experiment and by simulation