51 research outputs found
From Spinal Central Pattern Generators to Cortical Network: Integrated BCI for Walking Rehabilitation
No full textSuccess in locomotor rehabilitation programs can be improved with the use of brain-computer interfaces (BCIs). Although a wealth of research has demonstrated that locomotion is largely controlled by spinal mechanisms, the brain is of utmost importance in monitoring locomotor patterns and therefore contains information regarding central pattern generation functioning. In addition, there is also a tight coordination between the upper and lower limbs, which can also be useful in controlling locomotion. The current paper critically investigates different approaches that are applicable to this field: the use of electroencephalogram (EEG), upper limb electromyogram (EMG), or a hybrid of the two neurophysiological signals to control assistive exoskeletons used in locomotion based on programmable central pattern generators (PCPGs) or dynamic recurrent neural networks (DRNNs). Plantar surface tactile stimulation devices combined with virtual reality may provide the sensation of walking while in a supine position for use of training brain signals generated during locomotion. These methods may exploit mechanisms of brain plasticity and assist in the neurorehabilitation of gait in a variety of clinical conditions, including stroke, spinal trauma, multiple sclerosis, and cerebral palsy
Emerg Infect Dis
No full textWe report a rare case of aorto-bi-iliac prosthetic allograft mucormycosis in a 57-year-old immunocompetent patient in France. Outcome was favorable after surgery and dual antifungal therapy with liposomal amphotericin B and isavuconazole. In a literature review, we identified 12 other cases of prosthetic vascular or heart valve mucormycosis; mortality rate was 38%
EMG patterns during assisted walking in the exoskeleton
No full textNeuroprosthetic technology and robotic exoskeletons are being developed to facilitate stepping, reduce muscle efforts and promote motor recovery. Nevertheless, the guidance forces of an exoskeleton may influence the sensory inputs, sensorimotor interactions and resulting muscle activity patterns during stepping. The aim of this study was to report the muscle activation patterns in a sample of intact and injured subjects while walking with a robotic exoskeleton and, in particular, to quantify the level of muscle activity during assisted gait. We recorded electromyographic (EMG) activity of different leg and arm muscles during overground walking in an exoskeleton in six healthy individuals and four spinal cord injury (SCI) participants. In SCI patients, EMG activity of the upper limb muscles was augmented while activation of leg muscles was typically small. Contrary to our expectations, however, in neurologically intact subjects, EMG activity of leg muscles was similar or even larger during exoskeleton-assisted walking compared to normal overground walking. In addition, significant variations in the EMG waveforms were found across different walking conditions. The most variable pattern was observed in the hamstring muscles. Overall, the results are consistent with a non-linear reorganization of the locomotor output when using the robotic stepping devices. The findings may contribute to our understanding of human-machine interactions and adaptation of locomotor activity patterns
Maternal and professional identity change during the transition to motherhood
No full textBecoming a mother derails many women’s chances for career progression. One reason for this is that women leave organisations when they become mothers, or reduce their working hours. Another reason is that people within the organisation start to view them as less career-orientated as a result of being mothers. At the core of this issue is that who a woman is – her identity – is being redefined in the transition to motherhood, by herself and by those around her. But, little is known about how her professional identity develops during the transition to motherhood, or whether its development is related to her growing maternal identity. This paper, therefore, presents a systematic review of the literature concerning changes in maternal and professional identities, as well as the relationship between them. Based on the evidence, this review concludes that although the development of maternal identity has been well documented in the literature, little is known about how a woman’s professional identity develops, as she becomes a mother. Suggestions for further research and practice are discussed
The Effects of Age, Gender and Job Strain on Labour Market Outflow: An Exploratory Study
No full textThe objective of this study is to improve our understanding of the causes of replacement demand and labour market outflow. A better understanding of the factors that explain why workers flow out is needed for the Netherlands because this country is faced with a particularly high labour market outflow, reflected in a very low participation rate. In our investigation, we focus on different indicators of job strain, as well as variables such as age, gender and job level. We perform both univariate and multivariate regressions to find the effects of these variables on the net flows on the labour market. The regression results reveal that age, gender and (to a lesser extent) job level have the strongest connection with and effect on outflow. The regressions also show that job strain has hardly any noticeable effect on net flow.education, training and the labour market;
Report on representation and development of women for top leadership roles in the New Zealand public service
No full textNew Zealand has an enviable international reputation as a country where it is relatively common for women to hold top leadership roles in government and in organisations. Of 36 OECD countries, in 2003 New Zealand had the 4th highest representation of women in senior management with 31% of such positions held by women. However, by 2009 New Zealand had slipped to 17th position with 27% representation. The New Zealand Public Service in particular has traditionally had higher representation levels of women in senior management with 34% in 2001 climbing to a new high 40% in 2010. The proportion of women in public service chief executive roles averaged 23% per year for the years 2001 to 2006. However, it has declined from a high of 26% (9 out of 35) in 2005 to 14% (5 out of 35) in late 2010.
This paper focuses on appointments to CE positions in the New Zealand Public Service and in particular it examines:
- the extent to which women are applying for, being shortlisted for and being appointed to Public Service chief executive positions over the last decade - the extent to which women are represented in the potential pool for CE appointments and the previous roles of CE appointees - what can be done to increase the number of women who apply for and are appointed to Public Service chief executive positions
Female and male entrepreneurs in Sweden and the Netherlands: a test of liberal and social feminism
No full textThe purpose of this paper is to propose a nonparametric interest rate term structure model and investigate its implications on term structure dynamics and prices of interest rate derivative securities. The nonparametric spot interest rate process is estimated from the observed short-term interest rates following a robust estimation procedure and the market price of interest rate risk is estimated as implied from the historical term structure data. That is, instead of imposing a priori restrictions on the model, data are allowed to speak for themselves, and at the same time the model retains a parsimonious structure and the computational tractability. The model is implemented using historical Canadian interest rate term structure data. The parametric models with closed form solutions for bond and bond option prices, namely the Vasicek (1977) and CIR (1985) models, are also estimated for comparison purpose. The empirical results not only provide strong evidence that the traditional spot interest rate models and market prices of interest rate risk are severely misspecified but also suggest that different model specifications have significant impact on term structure dynamics and prices of interest rate derivative securities.
Gender Diversity and Firm Performance: Evidence from Dutch and Danish Boardrooms
No full textDrawing on the business case for gender diversity, this article examines whether board gender diversity has a positive effect on firm performance, based on evidence from the Netherlands and Denmark. We use empirical data on 186 listed firms observed in 2007, of which 102 Dutch and 84 Danish. Of these firms, almost 40% have at least one woman in the boardroom. Within boards the average share of women is only 5.4%. In order to investigate the impact of board gender diversity on firm performance, two-stage least-squares estimation is applied, using Tobin's Q as a measure of performance. Our findings indicate that there is no effect of board gender diversity on firm performance. This implies that the business case for board gender diversity is not supported for this particular sample. Our finding seems in line with most European research.Corporate governance, firm performance, board diversity, female board representation
Recurrent Neural Networks for Temporal Data Processing: Toward an Integrative Dynamic Recurrent Neural Network for Sensorimotor Coordination Dynamics
No full textThe utilization of dynamic recurrent neural networks (DRNN) for the interpretation of biological signals coming from human brain and body has acquired a significant growth in the field of brain-machine interface. DRNN approaches may offer an ideal tool for the identification of input-output relationships in numerous types of neural-based signals, such as intracellular synaptic potentials, local field potentials, EEG and EMG which integrate multiple sources of activity distributed across large neuronal assemblies. In the field of motor control, the output signals of the DRNN mapping concern movement-related kinematics signals such as position, velocity or acceleration of the different body segments involved. The most direct input signals consist in the electromyographic signals (EMG) recorded over the different superficial muscles implicated in movement generation. It is generally recognized that the non-invasive recording of the EMG envelope signal represents a reasonable reflection of the firing rate of the motoneuronal pools including both central and afferent influences (Cheron and Godaux, 1986). In addition, the combination of the multiple EMG signals may reveal the basic motor coordination dynamics of the gesture (Scholz and Kelso, 1990; Kelso, 1995). A major interest of the EMGs to kinematics mapping by a DRNN is that it may represent a new indirect way for a better understanding of motor organization elaborated by the central nervous system. After the learning phase and whatever the type of movement, the identification performed by the DRNN offers a dynamic memory which is able to recognize the preferential direction of the physiological action of the studied muscles (Cheron et al. 1996, 2003, 2006, 2007). In this chapter, we present the DRNN structure and the training procedure applied in case of noisy biological signals. Different DRNN applications are here reviewed in order to illustrate their usefulness in the field of motor control as diagnostic tools and potential prosthetic controllers
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