Nordic Electricity Congestion's Arrangement as a Model for Europe: Physical Constraints or Operators' Opportunity

Nordic Electricity Congestion's Arrangement as a Model for Europe: Physical Constraints or Operators' Opportunit

What happens after the NICU? Parents Experience of Caring for their Premature Infants at Home

This paper reviews the literature on what happens after the NICU with premature babies and their families and provides perspective of a lived experience. There have been numerous studies conducted on the traumatic experience of the NICU, however there is limited research involving the parenting process and experience following the NICU and caring for a high risk infant at home. Articles were searched through two databases, CINAHL and Pubmed, yielding 15 articles in which three specific themes were outlined; psychological distress of parents, perceptions of parents and linking family to resources. While there are programs available for families, not all families are provided access to these programs or other resources. It seems that further research should be conducted on parent’s experiences and finding out which services would be helpful after their stay in the NICU

Nordic electricity congestion's arrangement as a model for Europe : physical constraints or operators' opportunism?

Congestion on power grids seems a physical reality, a "hard" fact easy to check. Our paper models a different idea: congestion signal may be distorted by transmission system operators (TSOs), which puts the European integrated electricity market at risk. 1ʻ when the TSOs share the revenue produced by congestion's pricing they have an incentive in distorting data. 2ʻ because congestion signals are not physical data but "home made" conventions, TSOs could be able distorting them. 3ʻ when congestion appears on cross border lines that link several countries with their own regulatory mechanisms, the settlement of this incentive's problem necessitates a high degree of coordination. Congestion puts undoubtedly the threat of a collapse on interconnected grids. The "capacity constrained situations" have therefore to be avoided. Congestion signalling depends on norms set by TSOs and a signal is given when the power flows attain the "secure" limits set by TSOs. These security norms are not stable and invariable because some flexibility is needed by the very nature of the power flows and because lines physical capacity limits are not constant. Therefore TSOs are defining the congestion signal on a variable, complex and non transparent constraint and may manipulate it for their own interests. In Nordic countries the "Light Handed Regulation" makes this opportunistic behaviour more likely. We need a more effective congestion regulatory mechanism.Supported by the MIT Center for Energy and Environmental Policy Research

Sigmoid Neural Transfer Function Realised by Percolation

An experiment using the phenomenon of percolation has been conducted to demonstrate the implementation of neural functionality (summing and sigmoid transfer). A simple analog approximation to digital percolation is implemented. The device consists of a piece of amorphous silicon with stochastic bit-stream optical inputs, in which a current percolating from one end to the other defines the neuron output, also in the form of a stochastic bit stream. Preliminary experimental results are presented

Non-dynamic origin of the acoustic attenuation at high frequency in glasses

The sound attenuation in the THz region is studied down to T=16 K in glassy glycerol by inelastic x-ray scattering. At striking variance with the decrease found below 100 K in the GHz data, the attenuation in the THz range does not show any T dependence. This result i) indicates the presence of two different attenuation mechanisms, active respectively in the high and low frequency limits; ii) demonstrates the non-dynamic origin of the attenuation of THz sound waves, and confirms a similar conclusion obtained in SiO2 glass by molecular dynamics; and iii) supports the low frequency attenuation mechanism proposed by Fabian and Allen (Phys.Rev.Lett. 82, 1478 (1999)).Comment: 3 pages, 5 Figures, To be published in PR

Coordinating cross-border congestion management through auctions: An experimental approach to European solutions

International audienceCompetition among producers within an integrated electricity system is impeded by any limited transmission capacity there may be at its borders. Two alternative market mechanisms have recently been designed to organize the allocation of scarce transmission capacity at cross-border level: (i) the "implicit auction", already used in some countries, and (ii) the "coordinated explicit auction", proposed by the European Transmission System Operators (ETSO) but not implemented yet. The main advantage of the explicit auction is that it allows each country to keep its own power exchange running. In the European institutional context, this is seen as a factor of success of a market reform, although the explicit auction (not coordinated) is known to be less efficient than the implicit mechanism. The addition of a coordination dimension in the explicit auction is intended to solve problems of international flows. We use an experimental methodology to identify and compare in a laboratory setting the efficiency properties of these two market mechanisms, given a market structure similar to the existing one in continental Europe, i.e. a competitive oligopoly. Our main result highlights the inefficiency of the coordinated explicit auction compared to the performance of the implicit auction, measured in terms of both energy prices and transmission capacity allocation. We suggest that the poor performance of the coordinated explicit auction in the laboratory is due to the level of individual expectations about both energy and transmission prices that the mechanism demands. One solution to resolve this problem when the mechanism is implemented in the field would be to design an additional and secondary market for "used" transmission capacity

Rheo-acoustic gels: Tuning mechanical and flow properties of colloidal gels with ultrasonic vibrations

Colloidal gels, where nanoscale particles aggregate into an elastic yet fragile network, are at the heart of materials that combine specific optical, electrical and mechanical properties. Tailoring the viscoelastic features of colloidal gels in real-time thanks to an external stimulus currently appears as a major challenge in the design of "smart" soft materials. Here we introduce "rheo-acoustic" gels, a class of materials that are sensitive to ultrasonic vibrations. By using a combination of rheological and structural characterization, we evidence and quantify a strong softening in three widely different colloidal gels submitted to ultrasonic vibrations (with submicron amplitude and frequency 20-500 kHz). This softening is attributed to micron-sized cracks within the gel network that may or may not fully heal once vibrations are turned off depending on the acoustic intensity. Ultrasonic vibrations are further shown to dramatically decrease the gel yield stress and accelerate shear-induced fluidization. Ultrasound-assisted fluidization dynamics appear to be governed by an effective temperature that depends on the acoustic intensity. Our work opens the way to a full control of elastic and flow properties by ultrasonic vibrations as well as to future theoretical and numerical modeling of such rheo-acoustic gels.Comment: 21 pages, 14 figure

Individual patient data meta-analysis in cancer.

As in many areas of health care, treatments for cancer may differ only moderately in their effects on major end points, such as death. But, such differences are worth knowing about, particularly in common diseases in which they could represent a substantial benefit to public health. Large-scale randomized evidence allows moderate differences to be investigated reliably, and one way to achieve this is by meta-analyses of updated and centrally collected individual patient data from all relevant trials. This paper illustrates why this form of research can often be important in cancer. It also offers the first list of such projects, as a source of information on current and past research in this area