48 research outputs found
Form Factors from a Relativistic Dynamical Model of Pion Electroproduction
We obtain the electromagnetic form factors of the transition
by analyzing recent pion-electroproduction data using a fully relativistic
dynamical model. Special care is taken to satisfy Ward-Takahashi identities for
the Born term in the presence of form factors thereby allowing the use of
realistic electromagnetic form factors of the nucleon and pion. We parametrize
the dependence of the {\it bare} form factors by a
three-parameter form which is consistent with the asymptotic behavior inferred
from QCD. The parameters of the bare form factors are the
only free parameters of the model and are fitted to the differential
cross-section and multipole-analysis data up to (GeV/c) in the
-resonance region. This analysis emphasizes the significance of
the pion-cloud effects in the extraction of the resonance parameters.Comment: 9 pages, 5 figures, several small corrections, to be published in
Phys. Rev.
Different Methods for the Two-Nucleon T-Matrix in the Operator Form
We compare three methods to calculate the nucleon-nucleon t-matrix based on
the three-dimensional formulation of J. Golak et al., Phys. Rev. C 81, 034006,
(2010). In the first place we solve a system of complex linear inhomogeneous
equations directly for the t-matrix. Our second method is based on iterations
and a variant of the Lanczos algorithm. In the third case we obtain the
t-matrix in two steps, solving a system of real linear equations for the
k-matrix expansion coefficients and then solving an on-shell equation, which
connects the scalar coefficients of the k- and t-matrices. A very good
agreement among the three methods is demonstrated for selected nucleon-nucleon
scattering observables using a chiral next-to-next-to-leading-order
neutron-proton potential. We also apply our three-dimensional framework to the
demanding problem of proton-proton scattering, using a corresponding version of
the nucleon-nucleon potential and supplementing it with the (screened) Coulomb
force, taken also in the three-dimensional form. We show converged results for
two different screening functions and find a very good agreement with other
methods dealing with proton-proton scattering.Comment: 18 pages, 10 figures (54 eps files
The role of temporary accommodation buildings for post-disaster housing reconstruction
The number of houses damaged or destroyed after disasters is frequently large, and re-housing of homeless people is one of the most important tasks of reconstruction programmes. Reconstruction works often last long and during that time, it is essential to provide victims with the minimum conditions to live with dignity, privacy, and protection. This research intends to demonstrate the crucial role of temporary accommodation buildings to provide spaces where people can live and gradually resume their life until they have a permanent house. The study also aims to identify the main problems of temporary accommodation strategies and to discuss some principles and guidelines in order to reach better design solutions. It is found that temporary accommodation is an issue that goes beyond the simple provision of buildings, since the whole space for temporary settlement is important. Likewise, temporary accommodation is a process that should start before a disaster occurs, as a preventive pre-planning. In spite of being temporary constructions, these housing buildings are one of the most important elements to provide in emergency scenarios, contributing for better recovery and reconstruction actions.The first author gratefully acknowledges the financial support of Fundacao para a Ciencia e a Tecnologia, FCT, through grant SFRH/BD/73853/2010
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Environmental justice and conceptions of the green economy
Green economy has become one of the most fashionable terms in global environmental public policy discussions and forums. Despite this popularity, and its being selected as one of the organizing themes of the United Nations Rio+20 Conference in Brazil, June 2012, its prospects as an effective mobilization tool for global environmental sustainability scholarship and practice remains unclear. A major reason for this is that much like its precursor concepts such as environmental sustainability and sustainable development, green economy is a woolly concept which lends itself to many interpretations. Hence, rather than resolve long-standing controversies, green economy merely reinvigorates existing debates over the visions, actors and policies best suited to secure a more sustainable future for all. In this review article, we aim to fill an important gap in scholarship by suggesting various ways in which green economy may be organized and synthesized as a concept, and especially in terms of its relationship with the idea of social and environmental justice. Accordingly, we offer a systemization of possible interpretations of green economy mapped onto a synthesis of existing typologies of environmental justice. This classification provides the context for future analysis of which, and how, various notions of green economy link with various conceptions of justice
Study of in the vicinity of
Using 2917 of data accumulated at 3.773~,
44.5~ of data accumulated at 3.65~ and data accumulated
during a line-shape scan with the BESIII detector, the reaction
is studied considering a possible interference
between resonant and continuum amplitudes. The cross section of
,
, is found to have two
solutions, determined to be () pb with the phase angle
(0.11 pb at the 90% confidence level),
or ) pb with both of which
agree with a destructive interference. Using the obtained cross section of
, the cross section of , which is useful information for the future PANDA experiment, is
estimated to be either () nb ( nb at 90% C.L.) or
nb
The role of sleep in maximising performance in elite athletes
This chapter explores the characteristics of sleep and its function before providing insight into what is known about sleep in athletes. Limited research exists examining the effects of sleep loss on sporting performance. Sleep hygiene involves the practise of habits typifying appropriate behavioural and environmental sleep, in an attempt to promote optimal sleep quantity and quality. Athletes perceive sleep as an important recovery modality; however, elite athletes have often demonstrated compromised sleep. Athletes are required to deal with an array of psychosocial stressors while competing in elite sport. Regular air travel is common in elite sport, with athletes often required to travel domestically, and on occasion on long-haul international flights across multiple time zones. The amount and quality of sleep obtained by an athlete may also influence their predisposition to injury. Elite athletes appear vulnerable to losses in sleep, particularly following competition played at night, or when early morning training sessions are scheduled
The Prevalence Of Obstructive Sleep Apnea Within A Professional Rugby League Team: An Exploratory Study
Obstructive sleep apnea (OSA) is a disorder characterized by recurrent episodes of partial or complete obstruction of the upper airway. This results in non-restorative sleep leading to daytime sleepiness and decreased quality of life. It is estimated that 1-5% of the worldwide population suffer from OSA, however the prevalence within athletes is largely unknown
Obstructive sleep apnea in professional rugby league athletes: An exploratory study
Objectives To explore the prevalence of obstructive sleep apnea (OSA) within a professional rugby league team and determine associations of OSA with ethnicity, positional group, and physical characteristics.Design Observational prospective cohort study.Methods Twenty-two professional rugby league athletes underwent one night of home-based polysomnography with apnea-hypopnea index (AHI), rapid eye movement (REM)AHI, non-REMAHI and supineAHI determined to indicate OSA. Linear models were used to assess if playing position (back or forward) or ethnicity (European-Australian or Polynesian) influenced AHI, REMAHI, non-REMAHI and supineAHI. Models were also built to determine differences according to body composition.Results Seven athletes were classified with mild OSA (6 forwards and 1 back, 3 European-Australians, and 4 Polynesians) and three with moderate OSA (2 forwards and 1 back, 3 Polynesians). When considering ethnicity, differences were observed between Polynesians and European-Australians for REMAHI (ES = 0.90, p = 0.02). Increased body mass index (BMI) was associated with a moderate increase in AHI (r = 0.38, p = 0.04) and non-REMAHI (r = 0.36, p = 0.05), while higher skinfold thickness moderately related to a higher AHI (r = 0.40, p = 0.05) non-REMAHI (r = 0.47, p = 0.02), and supineAHI (r = 0.41, p = 0.04).Conclusions This exploratory study found 10 cases of OSA. Polynesian athletes and athletes classified as forwards constituted the majority of reported cases, suggesting their susceptibility to OSA. Furthermore, the data suggests that athletes with greater BMI and skinfold thickness may be predisposed to OSA