1,854 research outputs found
Gauge and Yukawa mediated supersymmetry breaking in the triplet seesaw scenario
We propose a novel supersymmetric unified scenario of the triplet seesaw
mechanism where the exchange of the heavy triplets generates both neutrino
masses and soft supersymmetry breaking terms. Our framework is very predictive
since it relates neutrino mass parameters, lepton flavour violation in the
slepton sector, sparticle and Higgs spectra and electroweak symmetry breakdown.
The phenomenological viability and experimental signatures in lepton flavor
violating processes are discussed.Comment: 11 pages, 3 eps figs. Comments and references added. Final version to
be published in Phys. Rev. Let
A lower bound in Nehari's theorem on the polydisc
By theorems of Ferguson and Lacey (d=2) and Lacey and Terwilleger (d>2),
Nehari's theorem is known to hold on the polydisc D^d for d>1, i.e., if H_\psi
is a bounded Hankel form on H^2(D^d) with analytic symbol \psi, then there is a
function \phi in L^\infty(\T^d) such that \psi is the Riesz projection of \phi.
A method proposed in Helson's last paper is used to show that the constant C_d
in the estimate \|\phi\|_\infty\le C_d \|H_\psi\| grows at least exponentially
with d; it follows that there is no analogue of Nehari's theorem on the
infinite-dimensional polydisc
A screening mechanism for extra W and Z gauge bosons
We generalize a previous construction of a fermiophobic model to the case of
more than one extra and gauge bosons. We focus in particular on the
existence of screening configurations and their implication on the gauge boson
mass spectrum. One of these configurations allows for the existence of a set of
relatively light new gauge bosons, without violation of the quite restrictive
bounds coming from the parameter. The links with Bess and
degenerate Bess models are also discussed. Also the signal given here by this
more traditional gauge extension of the SM could help to disentangle it from
the towers of Kaluza-Klein states over and gauge bosons in extra
dimensions.Comment: 23 pages, 1 figure, extended discussion on precision tests. To appear
in International Journal of Modern Physics
Catches in ghost-fishing octopus and fish traps in the northeastern Atlantic Ocean (Algarve, Portugal)
Ghost fishing is the term used to describe the continued capture of fish and other living organisms after a
fisherman has lost all control over the gear. Traps may be lost for a variety of reasons including theft, vandalism,
abandonment, interactions with other gear, fouling on the bottom (i.e., traps and ropes are caught on rocky substrate), bad weather, and human error (Laist, 1995). Annual trap loss can be as high as 20% to 50% of fished traps in some fisheries (Al-Masroori et al., 2004). Because lost traps can continue to fish for long periods, albeit
with decreasing efficiency over time (e.g., Smolowitz, 1978; Breen, 1987, 1990; Guillory, 1993), ghost fishing is
a concern in fisheries worldwide
Employment generation in Brazilian coffee regions
Due to the specific characteristics of coffee production on each of the main Brazilian states producers of arabica (Coffea arabica) and robusta coffee (Coffea canephora), a better understanding of the structural links between production and industrialization of coffee on those states and the national economy can provide subsides for implementation of public policies, essential to plan the coffee production and increase the sector competitiveness. Therefore, this study analyzed the employment generation in production and coffee industrialization in the major Brazilian production regions, based on an inter-regional input-output model, with seven regions, which represent the main coffee-producing states - Minas Gerais, Espirito Santo, São Paulo, Paraná, Bahia and Other States - with 44 sectors each, in a system of 308 sectors. The results indicated that the production of robusta coffee is the sector that generates more employments (total) per currency unit, and that arabica production sector is the fourth largest generator of employments, among the 44 sectors considered for the country. The results for each state emphasized the importance of farming and coffee industry for national and state economies.Coffee; Coffee Production; Input-Output
CFRP-based confinement strategies for RC columns-experimental and analytical research
The present work aims to compare the confinement effectiveness of full and partial wrapping of concrete elements under compression loads. The main results of the experimental program are presented and analysed. The Lam and Teng analytical model was applied to predict the compression stress-strain behaviour of concrete column elements partially confined by strips of CFRP lay-up sheets. The model performance is assessed using the experimental results.The authors of the present work wish to acknowledge the generous support provide by MBT Bettor Portugal and S&P Clever Reinforcement. The first author would like to thank the financial support by PRODEP action 5.3/N/199.014/01
Strategies for concrete confinement with strips of CFRP sheet
To increase the strength and the energy absorption capacity of concrete elements submitted
to compression loading, concrete cylinder specimens of 150 mm diameter and 300 mm height were confined
with strips of wet lay-up carbon fiber sheet (CFRP). To assess the influence of the width and number of
CFRP strips, and the number of CFRP layers per strip in the concrete compression strength and ductility, distinct
confinement arrangements were applied. The main results obtained are presented and analyzed in the
present work
Confinamento por cintagem total e parcial de elementos de betão com mantas de fibras de carbono
Relatório técnico 04-DEC/E-2
Stress-strain model for partial CFRP confined concrete
Concrete columns requiring strengthening intervention always contain a certain percentage of
steel hoops. Applying strips of wet lay-up carbon fiber reinforced polymer (CFRP) sheets in-between the
existent steel hoops might, therefore, be an appropriate confinement technique with both technical and
economic advantages, when full wrapping of a concrete column is taken as a basis of comparison.
To assess the effectiveness of the partial wrapping technique, circular cross section concrete columns
were confined by distinct CFRP arrangements and tested under direct compression. The experimental
program was designed to evaluate the influence of the concrete strength class, the stiffness of the wet lay-up
CFRP sheet, the distance between strips, the width of the strip, and the number of layers per each strip.
The Harajli et al. model was modified in order to predict the compression stress-strain behaviour of
reinforced concrete column elements partially and totally confined by CFRP lay-up sheets. The main results
of the experimental program are hereby presented and analysed. The model’s performance is assessed
using the experimental results
Confinamento de pilares de betão armado reforçados total e parcialmente com mantas de CFRP submetidos a carregamentos ciclícos de compressão
No sentido de contribuir para o aumento do conhecimento no âmbito do confinamento com
sistemas de CFRP de elementos de pilar submetidos a carregamentos cíclicos de
compressão, foi efectuado um programa experimental, cujos resultados são apresentados e
analisados no presente trabalho
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