35,825 research outputs found
Operator Analysis for Proton Decay in SUSY SO(10) GUT Models
Non-renormalizable operators both account for the failure of down quark and
charged lepton Yukawa couplings to unify and reduce the proton decay rate via
dimension-five operators in minimal SUSY SU(5) GUT. We extend the analysis to
SUSY SO(10) GUT models.Comment: Higgs sector clarified, two Refs adde
Experimental characterization of the structural response of adobe arches
Earth was one of the first construction materials used by mankind and has been used as a building material since ancient times until the present days. Its qualities related to thermal comfort, low cost or simple construction techniques have contributed to such a long tradition throughout the world with several different architectural expressions, integrating the culture and history of each region.
With the wide propagation of steel and concrete structures, there has been a general loss of the traditional knowledge in earth construction. This type of construction presents important structural fragilities and requires a special maintenance to preserve its qualities. In order to understand the structural behaviour of this type of structures, the associated construction methods and processes have to be considered.
Aveiro University has been developing studies on adobe constructions, with research on the material mechanical characterization, experimental study of the structural behaviour of adobe masonry walls and, more recently, in the development of a detailed survey methodology for the characterization of buildings in Aveiro district.
Integrated in these studies, arches with different geometries were built using adobe blocks and traditional construction methods. These arches were tested under different types of vertical loading (distributed symmetrical, distributed non-symmetrical and point load) until collapse. The experimental tests performed reproduce the typical loading conditions of these structures during construction and use. The tests conducted, the results obtained and the main conclusions attained are described in this paper
Urban environmental quality and wellbeing in the context of incomplete urbanization in Brazil: integrating directly experienced ecosystem services into planning
The benefits of urban greenspace to residents are increasingly recognized as important to planning for sustainable and healthy cities. However, the way that people interact with and benefit from urban greenspace is context dependent and conditioned by a range of social and material factors. This paper applies and expands the ecosystems services based approach to understanding urban environmental quality and the way in which greenspace is appropriated by residents in the context of incomplete urbanization in three peri-urban target areas in Brazil. We develop and employ the notion of indirect (scientifically detected) and directly experienced ecosystems services, and undertake a science based ecosystem services assessment and a qualitative analysis of interviews, walking narratives and images captured with a smartphone application to understand what functions urban greenspace serves in the daily life of the studied neighborhoods. Findings demonstrate how elements of urban greenspace and what can be termed ecosystem services serve both material and signifying functions and produce subjective and collective benefits and dis-benefits that hinge on aspects of livability such as quality of urban service delivery, housing status and perceptions of crime and neighborhood character. We identify factors that enable, hinder and motivate both active material and interpretative interactions with urban greenspace. The findings suggest that the relationship between ecosystem service provision and wellbeing is better understood as reciprocal rather than one way. Although at the neighborhood scale, fear of crime and poor access to urban services can hinder positive engagements with urban greenspace and experienced benefits form ES, urban squares and fringe vegetation is also being appropriated to address experienced disadvantages. Presently however these local interactions and ecosystem service benefits are overlooked in formal planning and conservation efforts and are increasingly compromised by growing population density and environmental degradation. We make recommendations for a nuanced assessment of the material and interpretative human-nature interactions and associated ecosystem services in an urban context, and discuss the potential for planning initiatives that could be employed to articulate and nurture these important interactions in our target areas
Caracterização patológica e construtiva de igrejas e capelas do concelho de Estarreja
Este estudo pretende enfatizar a importância de caracterizar construtivamente e
avaliar a preservação de imóveis pertencentes ao património social da Câmara Municipal de
Estarreja, ou seja, a sua herança religiosa e cultural.
São apresentadas 8 fichas criadas especificamente para a inspecção de edifícios religiosos,
procurando-se caracterizar os materiais e os sistemas estruturais e identificar os principais
sintomas patológicos encontrados em igrejas e capelas das sete freguesias do concelho de
Estarreja, bem como sua dimensão e frequência.
Parte deste trabalho consistiu na observação através de registos fotográficos do ambiente
dentro e fora de sete igrejas e dezassete capelas dando-se especial importância ao estado de
conservação de todos os elementos estruturais, realçando-se as paredes estruturais e não
estruturais.
O estado de conservação de cada elemento que compõe este tipo de construção foi
caracterizado com base em observações e na análise dos registos fotográficos. Em cada caso,
tentou-se enquadrar os danos observados numa escala de seis categorias de danos,
correspondendo a ausência de danos a zero e a existência de danos extensos a seis.
O trabalho realizado foi também integrado num CD multimédia interactivo, que reúne
informações detalhadas sobre os edifícios pesquisados e do seu estado de conservação [1]
Labels for non-individuals
Quasi-set theory is a first order theory without identity, which allows us to
cope with non-individuals in a sense. A weaker equivalence relation called
``indistinguishability'' is an extension of identity in the sense that if
is identical to then and are indistinguishable, although the
reciprocal is not always valid. The interesting point is that quasi-set theory
provides us a useful mathematical background for dealing with collections of
indistinguishable elementary quantum particles. In the present paper, however,
we show that even in quasi-set theory it is possible to label objects that are
considered as non-individuals. We intend to prove that individuality has
nothing to do with any labelling process at all, as suggested by some authors.
We discuss the physical interpretation of our results.Comment: 11 pages, no figure
FUSE Observations of the Magellanic Bridge Gas toward Two Early-Type Stars: Molecules, Physical Conditions, and Relative Abundance
We discuss FUSE observations of two early-type stars, DI1388 and DGIK975, in
the low density and low metallicity gas of Magellanic Bridge (MB). Toward
DI1388, the FUSE observations show molecular hydrogen, O VI, and numerous other
atomic or ionic transitions in absorption, implying the presence of multiple
gas phases in a complex arrangement. The relative abundance pattern in the MB
is attributed to varying degrees of depletion onto dust similar to that of halo
clouds. The N/O ratio is near solar, much higher than N/O in damped Ly-alpha
systems, implying subsequent stellar processing to explain the origin of
nitrogen in the MB. The diffuse molecular cloud in this direction has a low
column density and low molecular fraction. H2 is observed in both the
Magellanic Stream and the MB, yet massive stars form only in the MB, implying
significantly different physical processes between them. In the MB some of the
H2 could have been pulled out from the SMC via tidal interaction, but some also
could have formed in situ in dense clouds where star formation might have taken
place. Toward DGIK975, the presence of neutral, weakly and highly ionized
species suggest that this sight line has also several complex gas phases. The
highly ionized species of O VI, C IV, and Si IV toward both stars have very
broad features, indicating that multiple components of hot gas at different
velocities are present. Several sources (a combination of turbulent mixing
layer, conductive heating, and cooling flows) may be contributing to the
production of the highly ionized gas in the MB. Finally, this study has
confirmed previous results that the high-velocity cloud HVC 291.5-41.2+80 is
mainly ionized composed of weakly and highly ions. The high ion ratios are
consistent with a radiatively cooling gas in a fountain flow model.Comment: Accepted for publication in the ApJ (October 10, 2002). Added
reference (Gibson et al. 2000
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