3,967 research outputs found
Implementing Electricity Restructuring: Policies, Potholes, and Prospects
Electricity is one of the last U.S. industries in which competition is replacing regulation. We briefly review the technology for producing and delivering power, the history of electricity policy, and recent state and international experience. We then outline the major questions facing policymakers as they decide whether, when, and how to implement restructuring. We conclude with some thoughts on the California electricity crisis and other political controversies. Although the California experience has come to define what it means for electricity markets to fail, most of the problems it raised are among those we know how to solve or prevent. The still unresolved make-or-break issue remains whether the cooperation necessary to maintain reliability is compatible with the degree of competition necessary to bring about greater efficiency and lower prices. This paper draws upon our forthcoming book, Alternating Curents: Electricity Markets and Public Policy.electricity restructuring, regulation, deregulation
Molecular Regionalization of the Diencephalon
The anatomic complexity of the diencephalon depends on precise molecular and cellular regulative mechanisms orchestrated by regional morphogenetic organizers at the neural tube stage. In the diencephalon, like in other neural tube regions, dorsal and ventral signals codify positional information to specify ventro-dorsal regionalization. Retinoic acid, Fgf8, BMPs, and Wnts signals are the molecular factors acting upon the diencephalic epithelium to specify dorsal structures, while Shh is the main ventralizing signal. A central diencephalic organizer, the zona limitans intrathalamica (ZLI), appears after neurulation in the central diencephalic alar plate, establishing additional antero-posterior positional information inside diencephalic alar plate. Based on Shh expression, the ZLI acts as a morphogenetic center, which cooperates with other signals in thalamic specification and pattering in the alar plate of diencephalon. Indeed, Shh is expressed first in the basal plate extending dorsally through the ZLI epithelium as the development proceeds. Despite the importance of ZLI in diencephalic morphogenesis the mechanisms that regulate its development remain incompletely understood. Actually, controversial interpretations in different experimental models have been proposed. That is, experimental results have suggested that (i) the juxtaposition of the molecularly heterogeneous neuroepithelial areas, (ii) cell reorganization in the epithelium, and/or (iii) planar and vertical inductions in the neural epithelium, are required for ZLI specification and development. We will review some experimental data to approach the study of the molecular regulation of diencephalic regionalization, with special interest in the cellular mechanisms underlying planar inductions
Numerical simulation of laminar flow over hypersonic compression ramps
Available from British Library Document Supply Centre- DSC:DXN061559 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
P ORTOLAN: a Model-Driven Cartography Framework
Processing large amounts of data to extract useful information is an
essential task within companies. To help in this task, visualization techniques
have been commonly used due to their capacity to present data in synthesized
views, easier to understand and manage. However, achieving the right
visualization display for a data set is a complex cartography process that
involves several transformation steps to adapt the (domain) data to the
(visualization) data format expected by visualization tools. To maximize the
benefits of visualization we propose Portolan, a generic model-driven
cartography framework that facilitates the discovery of the data to visualize,
the specification of view definitions for that data and the transformations to
bridge the gap with the visualization tools. Our approach has been implemented
on top of the Eclipse EMF modeling framework and validated on three different
use cases
Forecasting aircraft stand requirements
The aim of this thesis is to obtain from a simulation procedure a
set of graphs to compute the number of aircraft stands required at an
airport.
The scope of the study has been set within airports from the size
of that of Birmingham up to those of the size of Manchester. A general
approach has been taken hoping that the graphs may be used in the case
of similar airports within the range.
A computer model is developed to compute stand requirements for 5
aircraft groups under 4 aircraft mixes and 5 flight type mixes. The
basic input variables taken into account in the model are aircraft
arrival time and stand occupancy time.
The model simulates the apron under three handling rules, the first one being that of stands mutually shared amongst the aircraft
groups, the second without stands sharing and the last case for stands
being partially shared.
With outputs from the simulation procedure a number of graphs are
plotted with arrivals per hour as the independent variable and stands
required as the dependent variable. The graphs are split into 4 groups
according to the aircraft mixes
Rad-hard vertical JFET switch for the HV-MUX system of the ATLAS upgrade Inner Tracker
This work presents a new silicon vertical JFET (V-JFET) device, based on the
trenched 3D-detector technology developed at IMB-CNM, to be used as switches
for the High-Voltage powering scheme of the ATLAS upgrade Inner Tracker. The
optimization of the device characteristics is performed by 2D and 3D TCAD
simulations. Special attention has been paid to the on-resistance and the
switch-off and breakdown voltages to meet the specific requirements of the
system. In addition, a set of parameter values has been extracted from the
simulated curves to implement a SPICE model of the proposed V-JFET transistor.
As these devices are expected to operate under very high radiation conditions
during the whole experiment life-time, a study of the radiation damage effects
and the expected degradation on the device performance is also presented at the
end of the paper.Comment: KEYWORDS: Radiation-hard electronics; Voltage distributions; Large
detector systems for particle and astroparticle physics. 9 Pages, 7 Figure
How complexity increases in development : An analysis of the spatial-temporal dynamics of Gene expression in Ciona intestinalis
The increase in complexity in an embryo over developmental time is perhaps one of the most intuitive processes of animal development. It is also intuitive that the embryo becomes progressively compartmentalized over time and space. In spite of this intuitiveness, there are no systematic attempts to quantify how this occurs. Here, we present a quantitative analysis of the compartmentalization and spatial complexity of Ciona intestinalis over developmental time by analyzing thousands of gene expression spatial patterns from the ANISEED database. We measure compartmentalization in two ways: as the relative volume of expression of genes and as the disparity in gene expression between body parts. We also use a measure of the curvature of each gene expression pattern in 3D space. These measures show a similar increase over time, with the most dramatic change occurring from the 112-cell stage to the early tailbud stage. Combined, these measures point to a global pattern of increase in complexity in the Ciona embryo. Finally, we cluster the different regions of the embryo depending on their gene expression similarity, within and between stages. Results from this clustering analysis, which partially correspond to known fate maps, provide a global quantitative overview about differentiation and compartmentalization between body parts at each developmental stage. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe
Phases Dynamic Balancer
Most of the current domestic installations are single phase, with contracted power equal to or less than 15 kW and with a potential difference of 230 V. When consumption is expected to be higher you choose to use three different alternating currents with a difference voltage of 400 V between them, which are called phases. This enables the subdivision of the installation in different single-phase circuits, fed independently with the neutral installation. These couples have, in turn, a difference in voltage of 230 V. The neutral is common for all three phases so that, if the system is balanced, no current flows through it. The problem with these installations is that they are designed to work in an offset manner, using phase loads, and simultaneously an equal amount of energy consumed by the three phases of the network. Connection to each of the phases makes independent single-phase loads or disturbance of the operation of the original phase circuit and, consequently, the corresponding increases in consumption, heating of engines, etc.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Método de diferenciación de Caolinitas y Cloritas
En el presente trabajo se hace una revision bibliografica de los distintos métodos de identificación de Caolinita y Clorita en mezclas naturales y artificiales, valorando la distinta problematica que presentan cada uno de ellos, y aplicandolos a muestras patrones y mezclas naturales que presentan esta problematica a fin de obtener una mejor valoraci6n de los distintos métodos expuesto
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