365 research outputs found
Industrial Development Policies and Performances in Southern China: Beyond the Specialised Industrial Cluster Program
none3The paper offers an updated picture of the policies implemented by the government of the Guangdong Province (China) to foster the industrial development and the technological upgrading of its territories. Among these policies is the promotion and the institutional acknowledgement of a growing number of industrial clusters, defined as “specialized towns”, characterized by a high spatial concentration of firms producing one specific item (or a limited range of similar products). In the view of the provincial and local governments these types of industrial development programs are used to increase firms agglomerations, spatial concentration and visibility, which in turn leads to increased specialization, industrial output, innovation and economic growth. However, little specific empirical evidence has been collected to support this view and the debate, at the national and international level, on the effectiveness of such interventions seems to be still largely ideological. The paper offers a contribution in this sense by offering a detailed description of the policy tools, by suggesting synthetic indexes to quantify policy efforts and industrial performances in Guangdong territories and by providing a first statistical analysis of these indexesmixedBarbieri E.; Di Tommaso M.R.; Bonnini S.Barbieri, Elisa; DI TOMMASO, Marco Rodolfo; Bonnini, Stefan
Supersymmetric Unification Without Low Energy Supersymmetry And Signatures for Fine-Tuning at the LHC
The cosmological constant problem is a failure of naturalness and suggests
that a fine-tuning mechanism is at work, which may also address the hierarchy
problem. An example -- supported by Weinberg's successful prediction of the
cosmological constant -- is the potentially vast landscape of vacua in string
theory, where the existence of galaxies and atoms is promoted to a vacuum
selection criterion. Then, low energy SUSY becomes unnecessary, and
supersymmetry -- if present in the fundamental theory -- can be broken near the
unification scale. All the scalars of the supersymmetric standard model become
ultraheavy, except for a single finely tuned Higgs. Yet, the fermions of the
supersymmetric standard model can remain light, protected by chiral symmetry,
and account for the successful unification of gauge couplings. This framework
removes all the difficulties of the SSM: the absence of a light Higgs and
sparticles, dimension five proton decay, SUSY flavor and CP problems, and the
cosmological gravitino and moduli problems. High-scale SUSY breaking raises the
mass of the light Higgs to about 120-150 GeV. The gluino is strikingly long
lived, and a measurement of its lifetime can determine the ultraheavy scalar
mass scale. Measuring the four Yukawa couplings of the Higgs to the gauginos
and higgsinos precisely tests for high-scale SUSY. These ideas, if confirmed,
will demonstrate that supersymmetry is present but irrelevant for the hierarchy
problem -- just as it has been irrelevant for the cosmological constant problem
-- strongly suggesting the existence of a fine-tuning mechanism in nature.Comment: Typos and equations fixed, references adde
Strong, weak and flavor scalar triplets for the CDF Wjj anomaly
A model describing the 4.1\sigma\ Wjj anomaly observed by the CDF experiment
at the Tevatron collider is introduced. It features new scalar particles which
are charged both under the SU(3)_C and the SU(2)_L gauge groups and which
couple to pairs of quarks. We introduce several identical replicas of the
scalar multiplets in order to leave an unbroken U(3)_Q x U(3)_U x U(3)_D flavor
symmetry to satisfy the constraints coming from flavor physics. We discuss the
LHC reach on the new scalar resonances both in the resonant production channel
(with the Wjj final state) and in the QCD pair production channel (with the 4j
final state).Comment: 17 pages, 6 figures and 4 table
SUSY Quivers, Intersecting Branes and the Modest Hierarchy Problem
We present a class of chiral non-supersymmetric D=4 field theories in which
quadratic divergences appear only at two loops. They may be depicted as ``SUSY
quivers'' in which the nodes represent a gauge group with extended e.g., N=4
SUSY whereas links represent bifundamental matter fields which transform as
chiral multiplets with respect to different N=1 subgroups. One can obtain this
type of field theories from simple D6-brane configurations on Type IIA string
theory compactified on a six-torus. We discuss the conditions under which this
kind of structure is obtained from D6-brane intersections. We also discuss some
aspects of the effective low-energy field theory. In particular we compute
gauge couplings and Fayet-Iliopoulos terms from the Born-Infeld action and show
how they match the field theory results. This class of theories may be of
phenomenological interest in order to understand the modest hierarchy problem
i.e., the stability of the hierarchy between the weak scale and a fundamental
scale of order 10-100 TeV which appears e.g. in low string scale models.
Specific D-brane models with the spectrum of the SUSY Standard Model and three
generations are presented.Comment: 36 pages, using JHEP3.cls, 8 figures. References update
Anisotropic dark energy stars
A model of compact object coupled to inhomogeneous anisotropic dark energy is
studied. It is assumed a variable dark energy that suffers a phase transition
at a critical density. The anisotropic Lambda-Tolman-Oppenheimer-Volkoff
equations are integrated to know the structure of these objects. The anisotropy
is concentrated on a thin shell where the phase transition takes place, while
the rest of the star remains isotropic. The family of solutions obtained
depends on the coupling parameter between the dark energy and the fermion
matter. The solutions share several features in common with the gravastar
model. There is a critical coupling parameter that gives non-singular black
hole solutions. The mass-radius relations are studied as well as the internal
structure of the compact objects. The hydrodynamic stability of the models is
analyzed using a standard test from the mass-radius relation. For each
permissible value of the coupling parameter there is a maximum mass, so the
existence of black holes is unavoidable within this model.Comment: 12 pages, 6 figures, final manuscript, Accepted for publication in
Astrophysics & Space Scienc
Saúde perinatal: baixo peso e classe social
A survey was carried out in Ribeirão Preto, S. Paulo State, Brazil, between June 1978 and May 1979 with a view to studying the prevalence of low birth weight and its occurrence among different social classes. Data were collected from 8,878 singleton live births in eight maternity hospitals, accounting for 98% of all births in the area. Social classes were determinated by the use of a model proposed by Singer and modified for epidemiological purposes by Barros. Out of the 8,878 births, 660 (7.5%) were of low birth weight. The prevalence of deficient weight at birth (between 2,500 and 2,999 grams) was of 21.1%. Analysis indicated that 50.6% of children with low birth weight were at term and the majority of them suffered form intrauterine growth retardation. The prevalence of low birth weight according to social class was seen to be lower in the bourgeoisie classes (ranging from 2.8% to 3.9%) and higher in working classes (from 7% up to 9.5%). Low birth weight (defined as < 2,500 grams) was used for purposes of comparison with other previous surveys. The percentage was lower in this study (8.3%) than that found in the Interamerican Investigation of Mortality in Childhood (8.7%), carried out in 1968-70. No statistically significant differences in the percentage of low birth weight were found in the case of Ribeirão Preto when these two surveys were compared.Estudou-se, em Ribeirão Preto, SP, Brasil, no período de 1º de junho de 1978 a 31 de maio de 1979, 98% do universo de nascidos vivos, totalizando 8.878 crianças nascidas de parto único. As taxas de baixo peso e de peso deficiente ao nascer foram de 7,5% e de 21,1%, respectivamente. A maioria dos nascimentos de baixo peso eram crianças a termo, 50,6%, representando casos de retardo de crescimento intra-uterino. A prevalência de baixo peso nas classes sociais foi de 3,2% na burguesia empresarial, 2,8% na burguesia gerencial, 3,9% na pequena burguesia, 7,0% no proletariado e 9,5% no subproletariado, o que demonstra uma profunda disparidade. Definindo-se o baixo peso como menor ou igual a 2.500 gramas e comparando os resultados alcançados (8,3%) com os de outro estudo clássico (8,7%), observou-se que não houve redução estatisticamente significativa na prevalência de baixo peso em Ribeirão Preto, no intervalo de uma década
Resting metabolic rate and respiratory quotient in human longevity
Significant changes in body composition, body fat distribution, and resting metabolic rate (RMR) occur with aging. Interestingly, studies on human longevity pointed out that long-lived subjects are less prone to the anthropometrics and metabolic derangement normally observed in the elderly. Indeed, the relationship between energy expenditure and longevity has been poorly investigated. Thus, energy expenditure parameters of 28 long-lived subjects were assessed and compared with those of 26 adults and 27 younger elderly. All subjects enrolled were female. In the whole population, RMR was negatively correlated with age (P < 0.05), waist to hip ratio (WHR) (P < 0.001), fat mass (P < 0.001), and percent body fat (P < 0.03); respiratory quotient (Rq) displayed an age-related decrease (P < 0.001) and was negatively correlated with WHR (P < 0.001) and fat-free mass (FFM) (P < 0.006). In multivariate analysis, both RMR and Rq had FFM, WHR, but not body mass index as significant and independent determinants. Splitting the whole study group into subgroups according to age, long-lived subjects had oxygen volume, carbon dioxide volume, and Rq significantly higher than aged subjects but lower than adult subjects. In addition, long-lived subjects had total volume of expired air and RMR greater than aged subjects but not different from ones found in adults. In long-lived subjects, Rq was negatively correlated with percent body fat (P < 0.02), plasma glucose (P < 0.05), free fatty acid (P < 0.05), and WHR (P < 0.05), whereas RMR was negatively correlated with WHR (P < 0.05). No significant associations of RMR and Rq with FFM were found. In conclusion, our data demonstrate that human longevity seems protected toward an age-related decline. It is likely that the lack of the anthropometrics derangement may preserve long-lived subjects from the age-related decrease in energy metabolism
Effects of SO(10)-inspired scalar non-universality on the MSSM parameter space at large tan beta
We analyze the parameter space of the (mu > 0, A_0 = 0) CMSSM at large tan
beta with a small degree of non-universality originating from D-terms and
Higgs-sfermion splitting inspired by SO(10) GUT models. The effects of such
non-universalities on the sparticle spectrum and observables such as (g-2)_mu,
B(b -> X_s gamma), the SUSY threshold corrections to the bottom mass and
Omega_CDM h^2 are examined in detail and the consequences for the allowed
parameter space of the model are investigated. We find that even small
deviations to universality can result in large qualitative differences compared
to the universal case; for certain values of the parameters, we find, even at
low m_16, that radiative electroweak symmetry breaking fails as a consequence
of either |mu|^2 < 0 or m_(A^0)^2 < 0. We find particularly large departures
from the mSugra case for the neutralino relic density, which is sensitive to
significant changes in the position and shape of the A^0 resonance and a
substantial increase in the Higgsino component of the LSP. However, we find
that the corrections to the bottom mass are not sufficient to allow for Yukawa
unification.Comment: 53 pages, 14 figures, elsart format, some minor corrections,
references adde
What if Supersymmetry Breaking Unifies beyond the GUT Scale?
We study models in which soft supersymmetry-breaking parameters of the MSSM
become universal at some unification scale, , above the GUT scale,
\mgut. We assume that the scalar masses and gaugino masses have common
values, and respectively, at . We use the
renormalization-group equations of the minimal supersymmetric SU(5) GUT to
evaluate their evolutions down to \mgut, studying their dependences on the
unknown parameters of the SU(5) superpotential. After displaying some generic
examples of the evolutions of the soft supersymmetry-breaking parameters, we
discuss the effects on physical sparticle masses in some specific examples. We
note, for example, that near-degeneracy between the lightest neutralino and the
lighter stau is progressively disfavoured as increases. This has the
consequence, as we show in planes for several different values
of , that the stau coannihilation region shrinks as
increases, and we delineate the regions of the plane
where it is absent altogether. Moreover, as increases, the focus-point
region recedes to larger values of for any fixed and
. We conclude that the regions of the plane that are
commonly favoured in phenomenological analyses tend to disappear at large
.Comment: 24 pages with 11 eps figures; references added, some figures
corrected, discussion extended and figure added; version to appear in EPJ
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