On maximal mobility of linearly connected spacesL n

A. P. Urbonas

doi:10.1007/bf02465557

The modulatory influence of end-point controllability on decisions between actions

Journal of Neurophysiology ◽

10.1152/jn.00081.2012 ◽

2012 ◽

Vol 108 (6) ◽

pp. 1764-1780 ◽

Cited By ~ 27

Author(s):

Ignasi Cos ◽

Farid Medleg ◽

Paul Cisek

Keyword(s):

Selection Process ◽

Dynamic Properties ◽

Human Subjects ◽

Reaching Movements ◽

End Point ◽

Gradual Process ◽

Path Distance ◽

Maximal Mobility ◽

Motor Actions ◽

Biomechanical Factors

Recent work has shown that human subjects are able to predict the biomechanical ease of potential reaching movements and use these predictions to influence their choices. Here, we examined how reach decisions are influenced by specific biomechanical factors related to the control of end-point stability, such as aiming accuracy or stopping control. Human subjects made free choices between two potential reaching movements that varied in terms of path distance and biomechanical cost in four separate blocks that additionally varied two constraints: the width of the targets (narrow or wide) and the requirement of stopping in them. When movements were unconstrained (very wide targets and no requirement of stopping), subjects' choices were strongly biased toward directions aligned with the direction of maximal mobility. However, as the movements became progressively constrained, factors related to the control of the end point gained relevance, thus reducing this bias. This demonstrates that, before movement onset, constraints such as stopping and aiming participate in a remarkably adaptive and flexible action selection process that trades off the advantage of moving along directions of maximal mobility for unconstrained movements against exploiting biomechanical anisotropies to facilitate control of end-point stability whenever the movement constraints require it. These results support a view of decision making between motor actions as a highly context-dependent gradual process in which the subjective desirability of potential actions is influenced by their dynamic properties in relation to the intrinsic properties of the motor apparatus.

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Changes in NMR-visible kidney cell phosphate with age and diet: relationship to phosphate transport

AJP Renal Physiology ◽

10.1152/ajprenal.1991.261.1.f153 ◽

1991 ◽

Vol 261 (1) ◽

pp. F153-F162 ◽

Cited By ~ 2

Author(s):

M. Barac-Nieto ◽

T. L. Dowd ◽

R. K. Gupta ◽

A. Spitzer

Keyword(s):

Nuclear Magnetic Resonance ◽

Guinea Pigs ◽

Absolute Magnitude ◽

Phosphate Transport ◽

Pi Transport ◽

Maximal Mobility ◽

Induced Changes ◽

The Relationship ◽

Pi Deprivation

To test the hypothesis that growth and dietary Pi affect the intracellular concentration of Pi ([Pi]i) as well as its renal reabsorption, we measured nuclear magnetic resonance (NMR)-visible [Pi]i in isolated perfused kidneys of less than 1- and greater than 4-wk-old guinea pigs fed various amounts of Pi. Changes in [Pi]i were correlated with those in fractional Pi reabsorption (FRPi) in vivo and in capacity (Vmax) for Na(+)-Pi cotransport in microvilli derived from animals of similar age and fed the same diets. In animals fed normal (0.76% Pi) diet, [Pi]i was lower (0.91 +/- 0.14 vs. 1.85 +/- 0.23 mM, P less than 0.05), whereas FRPi was higher (0.90 +/- 0.02 vs. 0.70 +/- 0.03, P less than 0.01) in less than 1- than in greater than 4-wk-old guinea pigs. Pi deprivation decreased [Pi]i in mature animals to 0.74 +/- 0.29 mM, P less than 0.05, and increased FRPi to 0.99 +/- 0.01. Excess dietary Pi increased [Pi]i in immature animals to 1.67 +/- 0.56 mM, P less than 0.05, and decreased FRPi to 0.55 +/- 0.03. Diet-induced changes in [Pi]i were associated with reciprocal changes in Vmax of similar absolute magnitude in immature and mature animals. However, diets that resulted in comparable [Pi]i at the two ages were associated with higher (P less than 0.05) Vmax in less than 1- than in greater than 4-wk-old animals. The reciprocal nature of the relationship between [Pi]i and renal Pi transport indicates that [Pi]i is primarily determined by Pi efflux from the cells or Pi organification rather than Pi influx through Na(+)-Pi cotransport. Findings indicate that changes in [Pi]i with growth or diet may be a cause but cannot be the consequence of changes in abundance or maximal mobility of Na(+)-Pi cotransporters. Data also indicate that factors in addition to low [Pi]i contribute to the high Na(+)-Pi cotransport capacity observed in renal microvilli of growing animals.

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μMAX Enhanced 190% of a Strained NMOS Based on SiGe Virtual Substrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.756-759.154 ◽

2013 ◽

Vol 756-759 ◽

pp. 154-157

Author(s):

Zhao Huan Tang ◽

Kai Zhou Tan ◽

Wei Cui ◽

Bin Wang

Keyword(s):

High Performance ◽

Silicon Layer ◽

Sige Layer ◽

Strained Silicon ◽

Low Field ◽

Source Current ◽

Maximal Mobility ◽

Better Than ◽

Strained Sige

Based on SiGe virtual substrate technology, a high-performance strained NMOS is obtained. By growing 2~3μm SiGe relaxed layer, 100~200nm strained SiGe layer and 20nm strained silicon layer, and also forming a P-well by multiple implantation technology, a surface strained NMOS is fabricated. Finally, Measured results shown that drain-source current and the low field maximal mobility of the strained NMOS are enhancement of up to 190% at Vgs=3.5V, which is almost three times to the value of common Silicon NMOS and is also better than the 170% reported in public.

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