11,726 research outputs found
Foliations modeling nonrational simplicial toric varieties
We establish a correspondence between simplicial fans, not necessarily
rational, and certain foliated compact complex manifolds called LVMB-manifolds.
In the rational case, Meersseman and Verjovsky have shown that the leaf space
is the usual toric variety. We compute the basic Betti numbers of the foliation
for shellable fans. When the fan is in particular polytopal, we prove that the
basic cohomology of the foliation is generated in degree two. We give evidence
that the rich interplay between convex and algebraic geometries embodied by
toric varieties carries over to our nonrational construction. In fact, our
approach unifies rational and nonrational cases.Comment: 24 pages, 4 figures, expository changes, references updated. Link to
the journal http://j.mp/BatZaf; Int. Math. Res. Not. 2015 (Published online
February 24, 2015
Light neutralino dark matter in MSSM
Three dark matter direct detection experiments, DAMA, COGENT and CRESST, have
reported a possible signal of WIMP interaction corresponding to very light
particles, close to the edge of the XENON 100 and CDMS sensitivity. Imposing
the latest constraints from colliders, flavour physics, electroweak precision
tests and direct and indirect dark matter searches, we show that viable MSSM
scenarios with a light neutralino, in agreement with all the present data, are
feasible. An analysis of the characteristics of the resulting scenarios will be
presented.Comment: 6 pages, 2 figures, contribution to the ICHEP 2012 Conference
proceedings, 4-11 July 2012, Melbourne, Australi
Implications of LHC Higgs and SUSY searches for MSSM
The implications of the LHC SUSY searches as well as the discovery of a new
bosonic state compatible with the lightest Higgs boson will be discussed in the
context of constrained and general MSSM scenarios. Exploring the MSSM through
the Higgs sector is an alternative and complementary path to direct searches,
and tight constraints on the MSSM parameter space can be obtained.Comment: 7 pages, 5 figures, contribution to the ICHEP 2012 Conference
proceedings, 4-11 July 2012, Melbourne, Australi
An update of the constraints on the phenomenological MSSM from the new LHC Higgs results
Updated results on the search of Higgs bosons at the LHC with up to 17/fb of
data have just been presented by the ATLAS and CMS collaborations. New
constraints are provided by the LHCb and XENON experiments with the observation
of the rare decay B_s -> mu+mu- and new limits on dark matter direct detection.
In this paper, we update and extend the results on the implications of these
data on the phenomenological Minimal Supersymmetric extension of the Standard
Model (pMSSM) by using high statistics, flat scans of its 19 parameters. The
new LHC data on bb and tau tau decays of the lightest Higgs state and the new
CMS limits from the tau tau searches for the heavier Higgs states set stronger
constraints on the pMSSM parameter space.Comment: 14 pages, 8 figures. This update is based on results presented at HCP
2012 and the December 2012 CERN Council LHC Jamboree. It features larger scan
statistics and additional plot
Convex Polytopes and Quasilattices from the Symplectic Viewpoint
We construct, for each convex polytope, possibly nonrational and nonsimple, a
family of compact spaces that are stratified by quasifolds, i.e. each of these
spaces is a collection of quasifolds glued together in an suitable way. A
quasifold is a space locally modelled on modulo the action of a
discrete, possibly infinite, group. The way strata are glued to each other also
involves the action of an (infinite) discrete group. Each stratified space is
endowed with a symplectic structure and a moment mapping having the property
that its image gives the original polytope back. These spaces may be viewed as
a natural generalization of symplectic toric varieties to the nonrational
setting.Comment: LaTeX, 29 pages. Revised version: TITLE changed, reorganization of
notations and exposition, added remarks and reference
Two brains in action: joint-action coding in the primate frontal cortex
Daily life often requires the coordination of our actions with those of another partner. After sixty years (1968-2018) of behavioral neurophysiology of motor control, the neural mechanisms which allow such coordination in primates are unknown. We studied this issue by recording cell activity simultaneously from dorsal premotor cortex (PMd) of two male interacting monkeys trained to coordinate their hand forces to achieve a common goal. We found a population of 'joint-action cells' that discharged preferentially when monkeys cooperated in the task. This modulation was predictive in nature, since in most cells neural activity led in time the changes of the "own" and of the "other" behavior. These neurons encoded the joint-performance more accurately than 'canonical action-related cells', activated by the action per se, regardless of the individual vs. interactive context. A decoding of joint-action was obtained by combining the two brains activities, using cells with directional properties distinguished from those associated to the 'solo' behaviors. Action observation-related activity studied when one monkey observed the consequences of the partner's behavior, i.e. the cursor's motion on the screen, did not sharpen the accuracy of 'joint-action cells' representation, suggesting that it plays no major role in encoding joint-action. When monkeys performed with a non-interactive partner, such as a computer, 'joint-action cells' representation of the "other" (non-cooperative) behavior was significantly degraded. These findings provide evidence of how premotor neurons integrate the time-varying representation of the self-action with that of a co-actor, thus offering a neural substrate for successful visuo-motor coordination between individuals.SIGNIFICANT STATEMENTThe neural bases of inter-subject motor coordination were studied by recording cell activity simultaneously from the frontal cortex of two interacting monkeys, trained to coordinate their hand forces to achieve a common goal. We found a new class of cells, preferentially active when the monkeys cooperated, rather than when the same action was performed individually. These 'joint-action neurons' offered a neural representation of joint-behaviors by far more accurate than that provided by the canonical action-related cells, modulated by the action per se regardless of the individual/interactive context. A neural representation of joint-performance was obtained by combining the activity recorded from the two brains. Our findings offer the first evidence concerning neural mechanisms subtending interactive visuo-motor coordination between co-acting agents
Foundational Questions About Values in Information Technology
In the contemporary debate about values, information technology constitutes an
important source of hard ethical questions and in turn is a testing area for the
moral theory of values. Values are difficult to track down and yet there are a number of
inquiries starting from economics, social psychology, ethics, and political theory
that engage with the cognitive, epistemic, and moral status of values. This paper is a
contribution to an account of values in connection with information technology. It
argues that information technology may provide further support to a theory of
values that is able to embrace the transformative effects of the digital revolution. In
particular, it is plausible that a non- ideal reflection on digital wrongdoings is better
equipped to produce substantive knowledge about values that have been
undermined than a different approach focused on ideal guiding values. Moreover,
information technology overcomes the vaunted fact/value dichotomy and supports
the fact/value entanglement. As the principal concern of data-mining and machine
-learning communities are ways of remedying a remarkable number of biases and
conformism in techno-social systems, it is within the bounds of possibility to
supplement the non-ideal theory from this new practical angle. I therefore call for a
fully conceptual consideration of values drawing on the experience and reflection
that is growing in the field of information technology
Truth, Knowledge, and Democratic Authority in the Public Health Debate
Quality of democratic arrangements does matter. This kind of conceptual
breakthrough has been made through painfully engagement with the
nonphilosophical area of inquiry arisen by the COVID-19 pandemic. The
pandemic has dramatically emphasized that health is a highly political domain. No
surprise then that it made possible to challenge common thought about
democratic procedures in political theory that considers procedure-independent
standards suspicious. Therefore it is fair to state that the COVID-19 pandemic
has taken the quality of democratic outcomes back on center stage in the debate
in political theory, which has been dominated by fair proceduralism’s claim not
to refer to any procedure-independent standards of good political decisions. The
aim of this paper is to justify the legitimacy and authority of public health policies
on the basis of arguments that do not simply are a matter of their being
democratic. In the
first part, I want to display and criticize the idea that
proceduralism’s not getting one’s hands dirty with the substance of decisions and
remaining neutrally adherent only to procedures is untenable in the present case.
Having criticized democratic theories that want to restrict themselves to purely
procedural values, in the
second part I will focus on the idea of knowledge and
make explicit its characters of being practical and shared. Eventually, it will help
to have one example. M-Health will show that many valuable insights would be
incompatible with the restrictions of the proceduralism. Philosophical
consideration of health will combine epistemic issues with political ones
triggered by technology and sharpened by the COVID-19 pandemic
Values and Identities. A policymaker’s guide
Abstract: This report presents the state-of-the-art scientific knowledge on values and identities from an interdisciplinary perspective.
Values are said to be the dominating forces in life and identities represent who we are and to whom we belong. Both shape the political
landscape in democracies and have gained in importance in recent decades. The report contains important insights for policymakers to
adapt their work to the challenges of our time, including a dedicated toolbox section. The scientific review and toolbox are complemented
by findings from a dedicated Eurobarometer on values and identities commissioned for this purpose.
Manuscript completed in September 2021
This publication is a Science for Policy report by the Joint Research Centre (JRC), the European Commission’s science and knowledge
service. It is part of the series Facts4EUFuture, a stream of reports for the future of Europe. It aims to provide evidence-based scientific
support to the European policymaking process.
The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor
any person acting on behalf of the Commission is responsible for the use that might be made of this publication. For information on
the methodology and quality underlying the data used in this publication for which the source is neither Eurostat nor other Commission
services, users should contact the referenced source. The designations employed and the presentation of material on the maps do not
imply the expression of any opinion whatsoever on the part of the European Union concernin
The Invisible Higgs Decay Width in the Add Model at the LHC
Assuming flat universal extra dimensions, we demonstrate that for a light
Higgs boson the process will be observable at the level at the LHC for the
portion of the Higgs-graviscalar mixing () and effective Planck mass
() parameter space where channels relying on visible Higgs decays fail to
achieve a signal. Further, we show that even for very modest values
of the invisible decay signal probes to higher than does the
(-independent) jets/\gam + missing energy signal from graviton
radiation. We also discuss various effects, such as Higgs decay to two
graviscalars, that could become important when is of order 1.Comment: 6 pages, 2 figures, To appear in the Proceedings of the Les Houches
Workshop 2003: ``Physics at TeV Colliders'', ed. F. Boudjem
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