4,072 research outputs found
The European Migration System and Global Justice. A First Appraisal
Migration is at the heart of the current political debate in Europe. Moreover,
the migration crisis has disclosed a number of normative and ethical issues
connected to the current management of migration in the EU. This report provides
a preliminary insight into the EU’s policy on migration. It looks specifically
at the terms the EU chooses, the definitions it devises and the concepts and
understandings it endorses in its migration policies. In order to grasp the actual
working of an emerging EU Migration System of Governance (EUMSG), the
same terms, concepts and definitions are also examined with reference to a set
of national cases: Italy, France, Germany, United Kingdom, Hungary, Greece
and Norway
Underwater calibration of dome port pressure housings.
Underwater photogrammetry using consumer grade photographic equipment can be feasible for different applications, e.g.
archaeology, biology, industrial inspections, etc. The use of a camera underwater can be very different from its terrestrial use due to
the optical phenomena involved. The presence of the water and camera pressure housing in front of the camera act as additional
optical elements. Spherical dome ports are difficult to manufacture and consequently expensive but at the same time they are the
most useful for underwater photogrammetry as they keep the main geometric characteristics of the lens unchanged. Nevertheless, the
manufacturing and alignment of dome port pressure housing components can be the source of unexpected changes of radial and
decentering distortion, source of systematic errors that can influence the final 3D measurements. The paper provides a brief
introduction of underwater optical phenomena involved in underwater photography, then presents the main differences between flat
and dome ports to finally discuss the effect of manufacturing on 3D measurements in two case studies
Exclusive πᵒ Electroproduction at W \u3e 2 GeV with CLAS
Exclusive neutral-pion electroproduction (ep → e\u27p\u27π0 was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections d4σ/dtdQ2dxBdΦπ and structure functions σT+ ϵσL, σTT, and σLT as functions of t were obtained over a wide range of Q2 and xB. The data are compared with Regge and handbag theoretical calculations. Analyses in both frameworks find that a large dominance of transverse processes is necessary to explain the experimental results. For the Regge analysis it is found that the inclusion of vector meson rescattering processes is necessary to bring the magnitude of the calculated and measured structure functions into rough agreement. In the handbag framework, there are two independent calculations, both of which appear to roughly explain the magnitude of the structure functions in terms of transversity generalized parton distributions
Induced Polarization of Λ1116 in Kaon Electroproduction
We have measured. the induced polarization of the Λ (1116) in the reaction ep →e′K+Λ , detecting the scattered e′ and K+ in the final state along with the proton from the decay Λ → pπ− . The present study used the CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance in invariant energy W (1.6≤ W ≤ 2.7 GeV) and covered the full range of the kaon production angle at an average momentum transfer Q2 = 1.90GeV2 . In this experiment a 5.50-GeV electron beam was incident upon an unpolarized liquid-hydrogen target. We have mapped out the W and kaon production angle dependencies of the induced polarization and found striking differences from photoproduction data over most of the kinematic range studied. However, we also found that the induced polarization is essentially Q2 independent in our kinematic domain, suggesting that somewhere below the Q2 covered here there must be a strong Q2 dependence. Along with previously published photo- and electroproduction cross sections and polarization observables, these data are needed for the development of models, such as effective field theories, and as input to coupled-channel analyses that can provide evidence of previously unobserved s -channel resonances
OBLIQUE PHOTOGRAMMETRY SUPPORTING 3D URBAN RECONSTRUCTION OF COMPLEX SCENARIOS
Accurate 3D city models represent an important source of geospatial information to support various “smart city” applications, such as space management, energy assessment, 3D cartography, noise and pollution mapping as well as disaster management. Even though remarkable progress has been made in recent years, there are still many open issues, especially when it comes to the 3D modelling of complex urban scenarios like historical and densely-built city centres featuring narrow streets and non-conventional building shapes. Most approaches introduce strong building priors/constraints on symmetry and roof typology that penalize urban environments having high variations of roof shapes. Furthermore, although oblique photogrammetry is rapidly maturing, the use of slanted views for façade reconstruction is not completely included in the reconstruction pipeline of state-of-the-art software. This paper aims to investigate state-of-the-art methods for 3D building modelling in complex urban scenarios with the support of oblique airborne images. A reconstruction approach based on roof primitives fitting is tested. Oblique imagery is then exploited to support the manual editing of the generated building models. At the same time, mobile mapping data are collected at cm resolution and then integrated with the aerial ones. All approaches are tested on the historical city centre of Bergamo (Italy)
Measurement of the Q(2) Dependence of the Deuteron Spin Structure Function g(1) and Its Moments at Low Q(2) with CLAS
We measured the g1 spin structure function of the deuteron at low Q2, where QCD can be approximated with chiral perturbation theory (χPT). The data cover the resonance region, up to an invariant mass of W ≈ 1.9 GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Γd1 and the spin polarizability γ0d are precisely determined down to a minimum Q2 of 0.02 GeV2 for the first time, about 2.5 times lower than that of previous data. We compare them to several χPT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χPT domain.
We measured the g1 spin structure function of the deuteron at low Q2, where QCD can be approximated with chiral perturbation theory (χPT). The data cover the resonance region, up to an invariant mass of W ≈1.9 GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Γ_{1}^{d} and the spin polarizability γ_{0}^{d} are precisely determined down to a minimum Q2 of 0.02 GeV2 for the first time, about 2.5 times lower than that of previous data. We compare them to several χPT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χPT domain
Resistance and the paradox of legal entitlement – A theoretical analysis of migrant women’s responses to domestic abuse in the host country
This article provides a theoretically informed examination of migrant women’s responses to domestic abuse in the host country. It departs from an analysis of research on South Asian women in England, on Portuguese women in England and on Portuguese women in Canada to suggest that women’s apparent lack of mobilisation of law (primarily by eschewing contact with the justice system of the host country and preferring informality), both perpetuates hegemonic discourses and presents a possibility for change. The theoretical approach undertaken combines literature on legal consciousness, power and resistance, and on socio-cultural structures and barriers that affect migrant women. The article ultimately suggests that, rather than an acceptance of hegemonic discourses, women’s behaviour is best understood as a form of resistance to, and from within, socio-cultural pressures encountered in everyday life; as a form of “entrenched” resistance
First Measurement of the Polarization Observable E in the p→ (ɣ→, π+) in Reaction up to 2.25 Gev
First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction ɣ→p→→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, Jfilich-Bonn, and SAID groups
Precise Determination of the Deuteron Spin Structure at Low to Moderate Q² with CLAS and Extraction of the Neutron Contribution
We present the final results for the deuteron spin structure functions obtained from the full data set collected in 2000–2001 with Jefferson Lab\u27s continuous electron beam accelerator facility (CEBAF) using the CEBAF large acceptance spectrometer (CLAS). Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.8 GeV were scattered from deuteron (15ND3 ) targets, dynamically polarized along the beam direction, and detected with CLAS. From the measured double-spin asymmetry, the virtual photon absorption asymmetry Ad1 and the polarized structure function gd1 were extracted over a wide kinematic range (0.05GeV2 \u3c Q2 \u3c 5GeV2 and 0.9 GeV \u3c W \u3c 3GeV ). We use an unfolding procedure and a parametrization of the corresponding proton results to extract from these data the polarized structure functions An1 and gn1 of the (bound) neutron, which are so far unknown in the resonance region, W \u3c 2 GeV. We compare our final results, including several moments of the deuteron and neutron spin structure functions, with various theoretical models and expectations, as well as parametrizations of the world data. The unprecedented precision and dense kinematic coverage of these data can aid in future extractions of polarized parton distributions, tests of perturbative QCD predictions for the quark polarization at large x , a better understanding of quark-hadron duality, and more precise values for higher-twist matrix elements in the framework of the operator product expansion
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