2,137 research outputs found
Top quark forward-backward asymmetry and W^prime bosons
The top quark forward-backward asymmetry measured at the Fermilab Tevatron
collider deviates from the standard model prediction. A W^prime boson model is
described, where the coupling W^prime-t-d is fixed by the tt_bar
forward-backward asymmetry and total cross section at the Tevatron. We show
that such a W^prime boson would be produced in association with a top quark at
the CERN Large Hadron Collider (LHC), thus inducing additional tt_bar+j events.
We use measurements of tt_bar+n-jet production from the LHC to constrain the
allowed W^prime-t-d couplings as a function of W^prime boson mass. We find that
this W^prime model is constrained at the 95% C.L. using 0.7 fb^{-1} of data
from the LHC, and could be fully excluded with 5 fb^{-1} of data.Comment: 6 pgs., 4 PS figure
RBF neural net based classifier for the AIRIX accelerator fault diagnosis
The AIRIX facility is a high current linear accelerator (2-3.5kA) used for
flash-radiography at the CEA of Moronvilliers France. The general background of
this study is the diagnosis and the predictive maintenance of AIRIX. We will
present a tool for fault diagnosis and monitoring based on pattern recognition
using artificial neural network. Parameters extracted from the signals recorded
on each shot are used to define a vector to be classified. The principal
component analysis permits us to select the most pertinent information and
reduce the redundancy. A three layer Radial Basis Function (RBF) neural network
is used to classify the states of the accelerator. We initialize the network by
applying an unsupervised fuzzy technique to the training base. This allows us
to determine the number of clusters and real classes, which define the number
of cells on the hidden and output layers of the network. The weights between
the hidden and the output layers, realising the non-convex union of the
clusters, are determined by a least square method. Membership and ambiguity
rejection enable the network to learn unknown failures, and to monitor
accelerator operations to predict future failures. We will present the first
results obtained on the injector.Comment: 3 pages, 4 figures, LINAC'2000 conferenc
L’évolution du taux de la plus-value en France (1951-1980)
The measurement of the rate of surplus-value, in France, during the last thirty years, refers to the Marxist economic theory of capitalism and araises theoretical and statistical problems.
FDI in Vietnam: An Empirical Study of an Economy in Transition
Vietnam has emerged as an alternative smaller emerging economy market for FDI in the last five years, attracting both domestic market seeking and export oriented FDI. Vietnam continues to attract significant East Asian and OECD investors. This paper analyses the economic determinants of FDI for a smaller Non-BRIC emerging country, undergoing a rapid transition to a market driven economy in a region of great competitiveness among host countries and growing attractiveness to major source countries. The regression models presented in this paper show that while macro-economic variables such as GDP and to a lesser extent labor costs were predictably significant as determinants of FDI in Vietnam, (as they are in developed economies), the loss of value of the Dong, both against the dollar and against SDR, was a significant and negative factor in the regression models. It appears the relationship of the value of the host currency to FDI in newly emerging countries may be different from that of the more developed countries. Tax rates, openness to trade and growth rate were not shown to be significant in this empirical analysis. Perhaps the traditional literature on FDI needs to be re-examined for the unique challenges facing the newly emerging economies such as CIVETS countries
A Model of Lepton Masses from a Warped Extra Dimension
In order to explain the non-hierarchical neutrino mixing angles and the
absence of lepton flavor violating processes in the context of warped extra
dimensions one needs to introduce bulk flavor symmetries. We present a simple
model of lepton masses and mixings in RS models based on the A4 non-abelian
discrete symmetry. The virtues of this choice are: (i) the natural appearance
of the tri-bimaximal mixing pattern; (ii) the complete absence of tree-level
flavor violations in the neutral sector; (iii) the absence of flavor gauge
bosons; (iv) the hierarchies in the charged lepton masses are explained via
wave-function overlaps. We present the minimal field content and symmetry
breaking pattern necessary to obtain a successful model of this type. The
bounds from electroweak precision measurements allow the KK mass scale to be as
low as 3 TeV. Tree-level lepton flavor violation is absent in this model, while
the loop induced mu -> e gamma branching fraction is safely below the
experimental bound
Some Aspects of New CDM Models and CDM Detection Methods
We briefly review some recent Cold Dark Matter (CDM) models. Our main focus
are charge symmetric models of WIMPs which are not the standard SUSY LSP's
(Lightest Supersymmetric Partners). We indicate which experiments are most
sensitive to certain aspects of the models. In particular we discuss the
manifestations of the new models in neutrino telescopes and other set-ups. We
also discuss some direct detection experiments and comment on measuring the
direction of recoil ions--which is correlated with the direction of the
incoming WIMP. This could yield daily variations providing along with the
annual modulation signatures for CDM.Comment: 14 page
(De)Bonding with embryos: The emotional choreographies of Portuguese IVF patients
In this article we develop the new concept of emotional choreography to describe how patients bond, debond and/or rebond with their embryos created in vitro using assisted reproductive technologies (ART). Using this concept, we explore how the patients' management of their own emotions intertwines with political, scientific, and religious factors. Our analysis relies on and further advances Thompson's concepts of ethical and ontological “choreography”. It is through these forms of choreography that complex contemporary biomedical issues with high political, ethical, and scientific stakes are negotiated, and through which different actors, entities, practices, roles, and norms undergo mutual constitution, reinforcement and (re)definition. Our article draws on the analysis of 69 in-depth interviews and the results of an online survey with 85 respondents.info:eu-repo/semantics/publishedVersio
L’évolution du taux de la plus-value en France (1951-1980)
The measurement of the rate of surplus-value, in France, during the last thirty years, refers to the Marxist economic theory of capitalism and araises theoretical and statistical problems. From a theoretical point of view and after discussing on the legitimacy of measuring the rate of surplus-value, the author mainly evocates the following problems. 1) what kind of workers generate surplus-value? 2) are engineers producers of surplus-value? 3) is it correct to use the data of national accounts to quantify a rate defined on an essential level? After mentioning the theoretical choices, the author examines the statistical aspects of the problems. According to his results and assumptions, his main conclusion is that the rate of surplus-value, in France, has grown up from 1950. But its rate has been getting slower and slower. The return of capitalist exploitation would have been decreasing. The economic policy worked out from 1974 to 1980 resulted in an increase of the rate of surplus-value without reaching the variations observed during the Vth RĂ©public
A Retro-Projected Robotic Head for Social Human-Robot Interaction
As people respond strongly to faces and facial features, both con-
sciously and subconsciously, faces are an essential aspect of social
robots. Robotic faces and heads until recently belonged to one of the
following categories: virtual, mechatronic or animatronic. As an orig-
inal contribution to the field of human-robot interaction, I present the
R-PAF technology (Retro-Projected Animated Faces): a novel robotic
head displaying a real-time, computer-rendered face, retro-projected
from within the head volume onto a mask, as well as its driving soft-
ware designed with openness and portability to other hybrid robotic
platforms in mind.
The work constitutes the first implementation of a non-planar mask
suitable for social human-robot interaction, comprising key elements
of social interaction such as precise gaze direction control, facial ex-
pressions and blushing, and the first demonstration of an interactive
video-animated facial mask mounted on a 5-axis robotic arm. The
LightHead robot, a R-PAF demonstrator and experimental platform,
has demonstrated robustness both in extended controlled and uncon-
trolled settings. The iterative hardware and facial design, details of the
three-layered software architecture and tools, the implementation of
life-like facial behaviours, as well as improvements in social-emotional
robotic communication are reported. Furthermore, a series of evalua-
tions present the first study on human performance in reading robotic
gaze and another first on user’s ethnic preference towards a robot face
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