On-demand hd video using Jini based grid

This research establishes the feasibility of using a network centric technology, Jini, to provide a grid framework on which to perform parallel video encoding. A solution was implemented using Jini and obtained real-time on demand encoding of a 480 HD video stream. Further, a projection is made concerning the encoding of 1080 HD video in real-time, as the current grid was not powerful enough to achieve this above 15fps. The research found that Jini is able to provide a number of tools and services highly applicable in a grid environment. It is also suitable in terms of performance and responds well to a varying number of grid nodes. The main performance limiter was found to be the network bandwidth allocation, which when loaded with a large number of grid nodes was unable to handle the traffic.

Measuring lexical diversity among L2 learners of French: an exploration of the validity of D, MTLD and HD-D as measures of language ability

In this study two new measures of lexical diversity are tested for the first time on French. The usefulness of these measures, MTLD (McCarthy and Jarvis (2010 and this volume) ) and HD-D (McCarthy and Jarvis 2007), in predicting different aspects of language proficiency is assessed and compared with D (Malvern and Richards 1997; Malvern, Richards, Chipere and Durán 2004) and Maas (1972) in analyses of stories told by two groups of learners (n=41) of two different proficiency levels and one group of native speakers of French (n=23). The importance of careful lemmatization in studies of lexical diversity which involve highly inflected languages is also demonstrated. The paper shows that the measures of lexical diversity under study are valid proxies for language ability in that they explain up to 62 percent of the variance in French C-test scores, and up to 33 percent of the variance in a measure of complexity. The paper also provides evidence that dependence on segment size continues to be a problem for the measures of lexical diversity discussed in this paper. The paper concludes that limiting the range of text lengths or even keeping text length constant is the safest option in analysing lexical diversity.

Chemical abundance analysis of the Be star HD 171054

In this work the results of a spectroscopic study of the southern field narrow-line Be star HD 171054 are presented. High dispersion and signal-to-noise ratio spectra allowed the estimation of the fundamental photospheric parameters such as the projected rotational velocity, effective temperature and superficial gravity from non-LTE stellar atmosphere models. From these parameters and microturbulence, the abundances of He, C, N, O, Mg, Al and Si for this object are estimated. Results show that C is depleted whereas N is overabundant compared with the sun and OB stars in the solar vicinity. Oxygen and helium are close to the solar value. Magnesium is down by 0.43 dex and aluminium and silicon are overabundant. (C) 2010 Elsevier B.V. All rights reserved.

Cell-cell signal-dependent dynamic interactions between HD-GYP and GGDEF domain proteins mediate virulence in Xanthomonas campestris

RpfG is a paradigm for a class of widespread bacterial two-component regulators with a CheY-like receiver domain attached to a histidine-aspartic acid-glycine-tyrosine-proline (HD-GYP) cyclic di-GMP phosphodiesterase domain. In the plant pathogen Xanthomonas campestris pv. campestris (Xcc), a two-component system comprising RpfG and the complex sensor kinase RpfC is implicated in sensing and responding to the diffusible signaling factor (DSF), which is essential for cell-cell signaling. RpfF is involved in synthesizing DSF, and mutations of rpfF, rpfG, or rpfC lead to a coordinate reduction in the synthesis of virulence factors such as extracellular enzymes, biofilm structure, and motility. Using yeast two-hybrid analysis and fluorescence resonance energy transfer experiments in Xcc, we show that the physical interaction of RpfG with two proteins with diguanylate cyclase (GGDEF) domains controls a subset of RpfG-regulated virulence functions. RpfG interactions were abolished by alanine substitutions of the three residues of the conserved GYP motif in the HD-GYP domain. Changing the GYP motif or deletion of the two GGDEF-domain proteins reduced Xcc motility but not the synthesis of extracellular enzymes or biofilm formation. RpfG-GGDEF interactions are dynamic and depend on DSF signaling, being reduced in the rpfF mutant but restored by DSF addition. The results are consistent with a model in which DSF signal transduction controlling motility depends on a highly regulated, dynamic interaction of proteins that influence the localized expression of cyclic di-GMP.

Anodal tDCS applied during strength training enhances motor cortical plasticity

Purpose:
The objective of this study was to assess the effect of anodal transcranial direct current stimulation (a-tDCS) on voluntary dynamic strength and cortical plasticity when applied during a 3-wk strength training program for the wrist extensors.

Methods:
Thirty right-handed participants were randomly allocated to the tDCS, sham, or control group. The tDCS and sham group underwent 3 wk of heavy-load strength training of the right wrist extensors, with 20 min of a-tDCS (2 mA) or sham tDCS applied during training (double blinded). Outcome measures included voluntary dynamic wrist extension strength, muscle thickness, corticospinal excitability, short-interval intracortical inhibition (SICI), and silent period duration.

Results:
Maximal voluntary strength increased in both the tDCS and sham groups (14.89% and 11.17%, respectively, both P < 0.001). There was no difference in strength gain between the two groups (P = 0.229) and no change in muscle thickness (P = 0.15). The tDCS group demonstrated an increase in motor-evoked potential amplitude at 15%, 20%, and 25% above active motor threshold, which was accompanied by a decrease in SICI during 50% maximal voluntary isometric contraction and 20% maximal voluntary isometric contraction (all P < 0.05). Silent period decreased for both the tDCS and sham groups (P < 0.001).

Conclusion:
The application of a-tDCS in combination with strength training of the wrist extensors in a healthy population did not provide additional benefit for voluntary dynamic strength gains when compared with standard strength training. However, strength training with a-tDCS appears to differentially modulate cortical plasticity via increases in corticospinal excitability and decreases in SICI, which did not occur following strength training alone

Formation of cortical plasticity in older adults following tDCS and motor training

Neurodegeneration accompanies the process of natural aging, reducing the ability to perform functional daily activities. Transcranial direct current stimulation (tDCS) alters neuronal excitability and motor performance; however its beneficial effect on the induction of primary motor cortex (M1) plasticity in older adults is unclear. Moreover, little is known as to whether the tDCS electrode arrangement differentially affects M1 plasticity and motor performance in this population. In a double-blinded, cross-over trial, we compared unilateral, bilateral and sham tDCS combined with visuomotor tracking, on M1 plasticity and motor performance of the non-dominant upper limb, immediately post and 30 min following stimulation. We found (a) unilateral and bilateral tDCS decreased tracking error by 12–22% at both time points; with sham decreasing tracking error by 10% at 30 min only, (b) at both time points, motor evoked potentials (MEPs) were facilitated (38–54%) and short-interval intracortical inhibition was released (21–36%) for unilateral and bilateral conditions relative to sham, (c) there were no differences between unilateral and bilateral conditions for any measure. These findings suggest that tDCS modulated elements of M1 plasticity, which improved motor performance irrespective of the electrode arrangement. The results provide preliminary evidence indicating that tDCS is a safe non-invasive tool to preserve or improve neurological function and motor control in older adults.

Anodal-tDCS applied during unilateral strength training increases strength and corticospinal excitability in the untrained homologous muscle

Evidence suggests that the cross-transfer of strength following unilateral training may be modulated by increased corticospinal excitability of the ipsilateral primary motor cortex, due to cross-activation. Anodal-tDCS (a-tDCS) has been shown to acutely increase corticospinal excitability and motor performance, which may enhance this process. Therefore, we sought to examine changes in neural activation and strength of the untrained limb following the application of a-tDCS during a single unilateral strength training session. Ten participants underwent three conditions in a randomized, double-blinded crossover design: (1) strength training + a-tDCS, (2) strength training + sham-tDCS and (3) a-tDCS alone. a-tDCS was applied for 20 min at 2 mA over the right motor cortex. Unilateral strength training of the right wrist involved 4 × 6 wrist extensions at 70 % of maximum. Outcome measures included maximal voluntary strength, corticospinal excitability, short-interval intracortical inhibition, and cross-activation. We observed a significant increase in strength of the untrained wrist (5.27 %), a decrease in short-interval intracortical inhibition (−13.49 %), and an increase in cross-activation (15.71 %) when strength training was performed with a-tDCS, but not following strength training with sham-tDCS, or tDCS alone. Corticospinal excitability of the untrained wrist increased significantly following both strength training with a-tDCS (17.29 %), and a-tDCS alone (15.15 %), but not following strength training with sham-tDCS. These findings suggest that a single session of a-tDCS combined with unilateral strength training of the right limb increases maximal strength and cross-activation to the contralateral untrained limb.

Anodal tDCS Prolongs the Cross-education of Strength and Corticomotor Plasticity

To assess the efficacy of applying anodal transcranial direct current stimulation (a-tDCS) to the ipsilateral motor cortex (iM1) during unilateral strength training to enhance the neurophysiological and functional effects of cross-education.

The effects of anodal-tDCS on cross-limb transfer in older adults

OBJECTIVE: Age-related neurodegeneration may interfere with the ability to respond to cross-limb transfer, whereby bilateral performance improvements accompany unilateral practice. We investigated whether transcranial direct current stimulation (tDCS) would facilitate this phenomena in older adults. METHODS: 12 young and 12 older adults underwent unilateral visuomotor tracking (VT), with anodal or sham-tDCS over the ipsilateral motor cortex. Transcranial magnetic stimulation (TMS) assessed motor evoked potentials (MEPs) and short interval intracortical inhibition (SICI). Performance was quantified through a VT error. Variables were assessed bilaterally at baseline and post-intervention. RESULTS: The trained limb improved performance, facilitated MEPs and released SICI in both age groups. In the untrained limb, VT improved in young for both sham and anodal-tDCS conditions, but only following anodal-tDCS for the older adults. MEPs increased in all conditions, except the older adult's receiving sham. SICI was released in both tDCS conditions for young and old. CONCLUSION: Following a VT task, older adults still display use-dependent plasticity. Although no significant age-related differences between the outcome measures, older adults exhibited significant cross-limb transfer of performance following anodal-tDCS, which was otherwise absent following motor practice alone. SIGNIFICANCE: These findings provide clinical implications for conditions restricting the use of one limb, such as stroke.