Temporary employment and employability: training opportunities and efforts of temporary and permanent employees.

The rise of temporary employment contributes to the fact that people can no longer count on life time employment with one employer. The conclusion that life time employment within the same organisation is no longer a prerogative for all, inspires the search for new career concepts. 'Life time employability' is often put forward as an alternative to 'life time employment'. A successful career is, then, believed to be assured by having and obtaining the appropriate capacities for being continuously employable on the internal and external labour market during one's working life. At first sight, temporary employment relations and employability go hand in hand. For temporary employment is less dramatic when it is linked to a higher employability. The career opportunities of temporary workers are safeguarded by their employability. Opponents, however, add some critical observations to this statement and claim that contractual flexibility and employability enhancement are at odds. In this article, we deal with this question. If temporary employment and employability enhancing activities are at odds, temporary employees get less facilities to expand their employability. This can have important implications for the career opportunities of temps. We compare the employability enhancing activities of temporary and permanent employees. We study one central employability enhancing activity, namely training. Firstly, we have a look at the capacity and the willingness of temporary and permanent employees to participate in training in order to enhance their employability. Secondly, we also study the training opportunities that are offered by employers to temporary and permanent employees. The results indicate that, although temps do largely take responsibility for their own training, they get less opportunities to enhance their employability than permanent employeEmployment;

Assessment of nerve cathodal block for the percutaneous auricular vagus nerve stimulation

Nerve cathodal block mechanism for the percutaneous auricular vagus nerve stimulation is investigated. The response of individual axons to stimulation will be assessed in terms of excitation, blocking and propagation of action potentials in order to optimize stimulation patterns. It was seen that the response obeyed the activating function remarkably well. The found sensitivity indices of the blocking threshold for variations in diameter and temperature (61 % and 15 % respectively) are significantly higher than for the excitation threshold. Finally, the threshold needed for cathodal block (around -5 V) is far from the amplitudes used to stimulate the nerves (around -1 V). More investigations by performing an uncertainty analysis varying axonal trajectories and electrode placement can lead to the conclusion that cathodal block is less likely to occur when stimulating with clinically used amplitudes in pVNS

Setting reference level in the human safety guidelines via nerve activation intercomparison at IF

International guidelines/standards have been published for human protection from electromagnetic field exposure. The research in the intermediate frequencies (IF: 300 Hz-10 MHz) is scattered unlike for other frequencies, and thus the limit prescribed in the guidelines/standards are different by a factor of 10. The IEEE International Committee on Electromagnetic Safety has published a research agenda for exploring the electrostimulation thresholds. However, the consistency of the excitation models for specific target tissue needs to be revised. For this purpose, we present the first intercomparison study using multiphysics modelling to investigate stimulation thresholds during transcranial magnetic stimulation (TMS). To define the stimulation threshold, a noninvasive technique for brain stimulation has been used. In this study, by incorporating individual neurons into electromagnetic computation in realistic head models, stimulation thresholds can be determined. The study case of one subject showed that the allowable external magnetic field strength in the current guidelines/standard is conservative

Exposure and neuronal excitation by wireless power transfer for auricular vagus nerve stimulation

Inductive wireless power transfer (WPT) can be used to power implanted as well as wearable medical devices, such as a percutaneous auricular vagus nerve stimulation device. This device is placed on the neck of the patient and is connected to needle electrodes in the auricle. With regard to WPT, limitations on exposure to electric and magnetic fields should not be exceeded. Furthermore, these fields should not interfere with the therapeutic goal of stimulation, i.e., with unintended peripheral nerve stimulation in the auricle. These effects are investigated by numerical simulation of induced internal fields in the head and neck and, for the first time, subsequent neuronal simulations, quantifying the potential of neuronal excitation by the fields in the auricle in particular. Internal electric field values were in the range of 1\%-5\% of the ICNIRP 2010 basic restrictions, and current densities were in the range of 30\%-45\% of the ICNIRP 1998 basic restrictions, indicating that all tested configurations are conform the guidelines. Basic restrictions on heating of tissue turned out not to be of relevance for this application. Thresholds for neuronal stimulation were two orders of magnitude higher than the induced fields, suggesting that there is almost no risk for unintended stimulation

Sensitivity study of neuronal excitation and cathodal blocking thresholds of myelinated axons for percutaneous auricular vagus nerve stimulation

Objective: Excitation of myelinated nerve fibers is investigated by means of numerical simulations, for the application of percutaneous auricular vagus nerve stimulation (pVNS). High sensitivity to axon diameter is of interest regarding the goal of targeting thicker fibers. Methods: Excitation and blocking thresholds for different pulse types, phase durations, axon depths, axon-electrode distances, temperatures and axon diameters are investigated. The used model consists of a 50 mm long axon and a centrally located needle electrode in a layered medium representing the auricle. Neuronal excitation is simulated using the Frankenhaeuser-Huxley equations for all combinations of parameter values. Results and conclusion: Multiple modes and locations of excitation along the axon were observed, depending on the pulse type and amplitude. When increasing the axon-electrode distance from 1 mm to 2 mm, sensitivity of thresholds to axon depth decreased with ca. 50%, while sensitivity to axon-electrode distance, axon diameter and phase duration each increased with ca. 15% to 20%, except from monophasic anodal pulses, showing a 45% decrease for axon-electrode distance. These trends for axon diameter and axon-electrode distance allow for more selective stimulation of thicker target fibers using monophasic anodal pulses at higher axon-electrode distances. Cathodal monophasic pulses did not perform well due to blocking of the thicker fibers, which was only rarely seen for other pulse types. Significance: Sensitivities of stimulation thresholds to these parameters by numerical simulation reveal how the stimulation parameters can be changed in order to increase therapeutic effect and comfort during pVNS by enabling more selective stimulation