Two-surface wave decay: improved analytical theory and effects on electron acceleration

Two-surface wave decay (TSWD), i.e. the parametric excitation of electron surface waves, was recently proposed as an absorption mechanism in the interaction of ultrashort, intense laser pulses with solid targets. We present an extension of the fluid theory of TSWD to a warm plasma which treats boundary effects consistently. We also present test-particle simulations showing localized enhancement of electron acceleration by TSWD fields; this effect leads to a modulation of the current density entering into the target and may seed current filamentation instabilities.Comment: 4 figures, submitted to Appl.Phys.B (special issue from HFSW X conference, Biarritz, France, Oct 12-15 2003); slightly revised tex

On Transmission Grid Governance

Meeting 100% of Europe.s electricity needs through renewable energy by 2050 is possible - if we succeed in pooling the potential of Europe's renewable energy sources. This will require cooperation between the EU member states, as well as coherent policies and regulation at the European level. Both currently exist only in fragments, as energy policy in Europe is still shaped mainly at the national level. The Heinrich Boell Foundation therefore asked a number of experts to take stock of European policy in the sectors most important for the transition to renewable energy, to identify the areas in which European cooperation has been inadequate to date, and to propose possible solutions. The construction of a European grid is a prerequisite for the joint exploitation of renewable energy sources in Europe. But although the necessity to construct such a grid is now widely accepted, the construction of this grid and especially of the interconnectors between the different European countries is progressing slowly. In this paper, Antonella Battaglini and Johan Lilliestam explore what could be done - especially on the European level - to speed up the construction of a European grid

BESTGRID Process: Going Beyond Existing Practices of Stakeholders’ Participation in Electricity Transmission Projects

The goals of climate change mitigation and energy security policies are key drivers for the EU energy transition towards low-carbon energy generation. Even though alternative technologies, including renewable energy, are well advanced, the current state of electricity grids is one of the bottlenecks for its further deployment. Inhabitants of communities affected by planned infrastructure are protesting against further projects to deploy electricity grids in many European countries. The innovative BESTGRID process brings together organized stakeholders from civil society, academia and the energy sector to understand the nature of concerns about these projects and to test various actions to address the concerns. The major research questions addressed by this work are: What are the main stakeholder concerns about the deployment of electricity transmission grids in Europe? What are successful actions to address these concerns? Which level of participation can be achieved in electricity transmission infrastructure project siting in Europe? We address these research questions through a variety of methods, which allow us to gain a systemic look and the holistic understanding of the problem. We analyse five real-world pilot projects which are under planning or construction in Germany (SuedLink and Bertikow-Pasewalk connections), UK (NEMO Link connection) and Belgium (Stevin and Waterloo-Braine l’Alleud connections). We collect empirical data through extensive dialogue with stakeholders, by observation of public and stakeholders information events on-site, by conducting interviews with key stakeholders, and by conducting an on-site survey of all communities where public information events were organized. We mapped participation in each project according to the methodology developed by Arnstein and finally analyzed how concerns about the planned power lines changed before and after actions and policy interventions, which were developed and tested in BESTGRID

Binding Mechanisms in Visual Perception and Their Link With Neural Oscillations: A Review of Evidence From tACS

Neurophysiological studies in humans employing magneto- (MEG) and electro- (EEG) encephalography increasingly suggest that oscillatory rhythmic activity of the brain may be a core mechanism for binding sensory information across space, time, and object features to generate a unified perceptual representation. To distinguish whether oscillatory activity is causally related to binding processes or whether, on the contrary, it is a mere epiphenomenon, one possibility is to employ neuromodulatory techniques such as transcranial alternating current stimulation (tACS). tACS has seen a rising interest due to its ability to modulate brain oscillations in a frequency-dependent manner. In the present review, we critically summarize current tACS evidence for a causal role of oscillatory activity in spatial, temporal, and feature binding in the context of visual perception. For temporal binding, the emerging picture supports a causal link with the power and the frequency of occipital alpha rhythms (8–12 Hz); however, there is no consistent evidence on the causal role of the phase of occipital tACS. For feature binding, the only study available showed a modulation by occipital alpha tACS. The majority of studies that successfully modulated oscillatory activity and behavioral performance in spatial binding targeted parietal areas, with the main rhythms causally linked being the theta (~7 Hz) and beta (~18 Hz) frequency bands. On the other hand, spatio-temporal binding has been directly modulated by parieto-occipital gamma (~40–60 Hz) and alpha (10 Hz) tACS, suggesting a potential role of cross-frequency coupling when binding across space and time. Nonetheless, negative or partial results have also been observed, suggesting methodological limitations that should be addressed in future research. Overall, the emerging picture seems to support a causal role of brain oscillations in binding processes and, consequently, a certain degree of plasticity for shaping binding mechanisms in visual perception, which, if proved to have long lasting effects, can find applications in different clinical populations

Social challenges of electricity transmission: grid Deployment in Germany, the United Kingdom, and Belgium

The European Union needs to decarbonize its energy generation to reach its goals of climate change mitigation and energy security policies. In 2011, the European Commission published a road map to reduce greenhouse gases (GHG) by at least 80% by 2050. The road map foresees five pathways, and, across all of them, renewable energy generation plays a significantly stronger role today. The deployment of renewable energy sources (RES)to generate electricity is one possible option to decarbonize energy generation. The goals of the European energy security policy require restructuring energy generation toward a greater share of lowcarbon energy generation. In October 2014, EU leaders agreed on the 2030 policy framework for climate and energy, which settles the GHG reduction target of 40% compared to 1990, as well as an increase of the share of renewable energy to at least 27% of EU energy consumption by 2030

The importance of monitoring cerebral oxygenation in non brain injured patients

Over the past few years, the use of non-invasive neuromonitoring in non-brain injured patients has increased, as a result of the recognition that many of these patients are at risk of brain injury in a wide number of clinical scenarios and therefore may benefit from its application which allows interventions to prevent injury and improve outcome. Among these, are post cardiac arrest syndrome, sepsis, liver failure, acute respiratory failure, and the perioperative settings where in the absence of a primary brain injury, certain groups of patients have high risk of neurological complications. While there are many neuromonitoring modalities utilized in brain injured patients, the majority of those are either invasive such as intracranial pressure monitoring, require special skill such as transcranial Doppler ultrasonography, or intermittent such as pupillometry and therefore unable to provide continuous monitoring. Cerebral oximetry using Near infrared Spectroscopy, is a simple non invasive continuous measure of cerebral oxygenation that has been shown to be useful in preventing cerebral hypoxemia both within the intensive care unit and the perioperative settings. At present, current recommendations for standard monitoring during anesthesia or in the general intensive care concentrate mainly on hemodynamic and respiratory monitoring without specific indications regarding the brain, and in particular, brain oximetry. The aim of this manuscript is to provide an up-to-date overview of the pathophysiology and applications of cerebral oxygenation in non brain injured patients as part of non-invasive multimodal neuromonitoring in the early identification and treatment of neurological complications in this population

Moving towards 100% renewable electricity in Europe & North Africa by 2050

In spring 2010, European and international climate experts at PwC, the European Climate Forum, the Potsdam Institute for Climate Impact Research and the International Institute for Applied System Analysis published 100% Renewable Electricity - A roadmap to 2050 for Europe and North Africa. The report examined the potential for powering Europe and North Africa with renewable electricity exclusively by 2050. It set out a series of financial, market, infrastructure and government policy steps that would need to occur if such a "what if" vision was to be achieved. Now, a year on, this latest report provides a complementary analysis to the original roadmap. PwC, the Potsdam Institute for Climate Impact Research and the International Institute for Applied System Analysis, look at whether the vision of 100% renewable electricity has moved closer or further away as a result of current and recent developments over the last 12 months. The report, intended to support the wider debate in this area, examines five areas that are most critical to achieving progress and, through the lens of these five areas, looks at the impact of recent and current events

T2 lesion location really matters: a 10 year follow-up study in primary progressive multiple sclerosis

Objectives: Prediction of long term clinical outcome in patients with primary progressive multiple sclerosis (PPMS) using imaging has important clinical implications, but remains challenging. We aimed to determine whether spatial location of T2 and T1 brain lesions predicts clinical progression during a 10-year follow-up in PPMS. Methods: Lesion probability maps of the T2 and T1 brain lesions were generated using the baseline scans of 80 patients with PPMS who were clinically assessed at baseline and then after 1, 2, 5 and 10 years. For each patient, the time (in years) taken before bilateral support was required to walk (time to event (TTE)) was used as a measure of progression rate. The probability of each voxel being ‘lesional’ was correlated with TTE, adjusting for age, gender, disease duration, centre and spinal cord cross sectional area, using a multiple linear regression model. To identify the best, independent predictor of progression, a Cox regression model was used. Results: A significant correlation between a shorter TTE and a higher probability of a voxel being lesional on T2 scans was found in the bilateral corticospinal tract and superior longitudinal fasciculus, and in the right inferior fronto-occipital fasciculus (p<0.05). The best predictor of progression rate was the T2 lesion load measured along the right inferior fronto-occipital fasciculus (p=0.016, hazard ratio 1.00652, 95% CI 1.00121 to 1.01186). Conclusion: Our results suggest that the location of T2 brain lesions in the motor and associative tracts is an important contributor to the progression of disability in PPMS, and is independent of spinal cord involvement