Comparative and International Legal Study on the Position of Irregular Migrants in the United Kingdom, Russia and South Africa: Issues of Their Internal Legal Capacity and Immigration Control Regimes

PhDThe present thesis deals with the legal position of irregular migrants in the three receiving societies, i. e. Britain, Russia and South Africa. Irregular migrants are an exploited underclass enjoying very few, if any, entitlements in the host countries and so long as their numbers are substantial their status becomes problematic both for them and the receiving society. To deal with these challenges, I propose that immigration policies or regimes, directly or indirectly related to regulation of the irregular migrants' position (internal legal capacity) are too restrictive and discriminatory for the position of irregular migrants and do not constitute an effective means of immigration control. In order to test this hypothesis, a socio-legal analysis of irregular migrants' position is made in the following spheres: entry, residence, employment (including temporary labour migration policies) and social welfare. The position of asylum seekers constitutes an integral part of the present analysis. The research led to two general conclusions in relation to irregular migration. First of all, irregular migrants should be granted at least a limited internal juridical capacity in the countries of residence. Secondly, there should be a more liberal labour migration policy and more balanced approaches to the humanitarian needs of immigrants. These liberal solutions could nevertheless be combined with rigorous internal control

In situ synthesis, structural chemistry and vibrational spectroscopy of Zn-doped Ca5Mg4(VO4)6

The phase formation of the solid solution Ca5Mg4–xZnx(VO4)6 (0≤x≤4) was studied in situ using differential scanning calorimetry and high-temperature X-Ray powder diffraction (XRPD). XRPD analysis shows the appearance of unavoidable secondary pyrovanadate phases using conventional synthesis methods. The local structure of the solid solution was verified by vibrational spectroscopy. The analysis of the infrared and Raman spectroscopy data allows establishing the main features between vanadate garnets and their isostructural analogs among natural silicates

Search for exotic resonances decaying into WZ/ZZ in pp collisions at √s=7 TeV

Journal of High Energy Physics 2013.2 (2013): 036 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMA search for new exotic particles decaying to the VZ final state is performed, where V is either a W or a Z boson decaying into two overlapping jets and the Z decays into a pair of electrons, muons or neutrinos. The analysis uses a data sample of pp collisions corresponding to an integrated luminosity of 5 fb-1 collected by the CMS experiment at the LHC at √s=7 TeV in 2011. No significant excess is observed in the mass distribution of the VZ candidates compared with the background expectation from standard model processes. Model-dependent upper limits at the 95% confidence level are set on the product of the cross section times the branching fraction of hypothetical particles decaying to the VZ final state as a function of mass. Sequential standard model W′ bosons with masses between 700 and 940 GeV are excluded. In the Randall-Sundrum model for graviton resonances with a coupling parameter of 0.05, masses between 750 and 880 GeV are also exclude

Searches for long-lived charged particles in pp collisions at √s =7 and 8 TeV

Results of searches for heavy stable charged particles produced in pp collisions at √s =7 and 8 TeV are presented corresponding to an integrated luminosity of 5.0 fb⁻¹ and 18.8 fb⁻¹, respectively. Data collected with the CMS detector are used to study the momentum, energy deposition, and time-of-flight of signal candidates. Leptons with an electric charge between e/3 and 8e, as well as bound states that can undergo charge exchange with the detector material, are studied. Analysis results are presented for various combinations of signatures in the inner tracker only, inner tracker and muon detector, and muon detector only. Detector signatures utilized are long time-of-flight to the outer muon system and anomalously high (or low) energy deposition in the inner tracker. The data are consistent with the expected background, and upper limits are set on the production cross section of long-lived gluinos, scalar top quarks, and scalar τ leptons, as well as pair produced long-lived leptons. Corresponding lower mass limits, ranging up to 1322 GeV/c² for gluinos, are the most stringent to date

Searches for heavy Higgs bosons in two-Higgs-doublet models and for t → c h decay using multilepton and diphoton final states in p p collisions at 8 TeV

Searches are presented for heavy scalar (H) and pseudoscalar (A) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of pp collisions collected with the CMS experiment at the LHC at a center-of-mass energy of root s = 8 TeV and corresponding to an integrated luminosity of 19.5 fb(-1). The decays H - GT hh and A - GT Zh, where h denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the H and A production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% C.L. cross section upper limits of approximately 7 pb on sigma B for H - GT hh and 2 pb for A - GT Zh. Also presented are the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, t - GT ch, the existence of which would indicate a nonzero flavor-changing Yukawa coupling of the top quark to the Higgs boson. We place a 95% C.L. upper limit of 0.56% on B(t - GT ch)

Novel Red Phosphor of Gd³⁺, Sm³⁺ co-Activated Ag<i>_x</i>Gd_{((2−<i>x</i>)/3)−0.3−<i>y</i>}Sm<i>_y</i>Eu³⁺_0.30☐_{(1−2<i>x</i>−2<i>y</i>)/3}WO₄ Scheelites for LED Lighting

Gd3+ and Sm3+ co-activation, the effect of cation substitutions and the creation of cation vacancies in the scheelite-type framework are investigated as factors influencing luminescence properties. AgxGd((2−x)/3)−0.3−ySmyEu3+0.3☐(1−2x)/3WO4 (x = 0.50, 0.286, 0.20; y = 0.01, 0.02, 0.03, 0.3) scheelite-type phases (AxGSyE) have been synthesized by a solid-state method. A powder X-ray diffraction study of AxGSyE (x = 0.286, 0.2; y = 0.01, 0.02, 0.03) shows that the crystal structures have an incommensurately modulated character similar to other cation-deficient scheelite-related phases. Luminescence properties have been evaluated under near-ultraviolet (n–UV) light. The photoluminescence excitation spectra of AxGSyE demonstrate the strongest absorption at 395 nm, which matches well with commercially available UV-emitting GaN-based LED chips. Gd3+ and Sm3+ co-activation leads to a notable decreasing intensity of the charge transfer band in comparison with Gd3+ single-doped phases. The main absorption is the 7F0 → 5L6 transition of Eu3+ at 395 nm and the 6H5/2 → 4F7/2 transition of Sm3+ at 405 nm. The photoluminescence emission spectra of all the samples indicate intense red emission due to the 5D0 → 7F2 transition of Eu3+. The intensity of the 5D0 → 7F2 emission increases from ~2 times (x = 0.2, y = 0.01 and x = 0.286, y = 0.02) to ~4 times (x = 0.5, y = 0.01) in the Gd3+ and Sm3+ co-doped samples. The integral emission intensity of Ag0.20Gd0.29Sm0.01Eu0.30WO4 in the red visible spectral range (the 5D0 → 7F2 transition) is higher by ~20% than that of the commercially used red phosphor of Gd2O2S:Eu3+. A thermal quenching study of the luminescence of the Eu3+ emission reveals the influence of the structure of compounds and the Sm3+ concentration on the temperature dependence and behavior of the synthesized crystals. Ag0.286Gd0.252Sm0.02Eu0.30WO4 and Ag0.20Gd0.29Sm0.01Eu0.30WO4, with the incommensurately modulated (3 + 1)D monoclinic structure, are very attractive as near-UV converting phosphors applied as red-emitting phosphors for LEDs

Structural and Vibrational Properties of the Ordered Y₂CaGe₄O₁₂ Germanate: A Periodic Ab Initio Study

DFT calculations with six LDA, GGA, and hybrid functionals have been performed using the CRYSTAL09 code to describe the crystal structure and vibrational spectra of Y₂CaGe₄O₁₂ cyclotetragermanate, a new optical host. Two space groups <i>P</i>4/<i>nbm</i> and <i>Cmme</i> have been considered. The former corresponds to a mixed (0.5 Ca + 0.5 Y) distribution at the octahedral sites found from the results of Rietveld refinement of room temperature powder XRD pattern; the latter refers to the model of crystallographically nonequivalent calcium and yttrium atomic setting in distorted oxygen octahedrons. The most accurate geometry description has been obtained with the WC1LYP and PBE (<i>n</i> = 6) hybrid functionals, while the B3LYP calculation provides the best agreement between the recorded infrared and Raman spectra and their computed counterparts. Assignments of most of the observed bands to vibrational modes are given. The comparison between calculated and experimental frequencies shows a general good agreement for the spectra below 600 cm^–1. The relationship between selected infrared bands and Raman lines, internal vibrations of the [Ge₄O₁₂] unit, and external modes is briefly discussed

Luminescence Property Upgrading via the Structure and Cation Changing in Ag_<i>x</i>Eu_{(2–<i>x</i>)/3}WO₄ and Ag_<i>x</i>Gd_{(2–<i>x</i>)/3–0.3}Eu_0.3WO₄

The creation and ordering of A-cation vacancies and the effect of cation substitutions in the scheelite-type framework are investigated as a factor for controlling the scheelite-type structure and luminescence properties. Ag_<i>x</i>Eu³⁺_{(2–<i>x</i>)/3}□_{(1–2<i>x</i>)/3}WO₄ and Ag_<i>x</i>Gd_{(2−<i>x</i>)/3−0.3}Eu³⁺_0.3□_{(1−2<i>x</i>)/3}WO₄ (<i>x</i> = 0.5–0) scheelite-type phases were synthesized by a solid state method, and their structures were investigated using a combination of transmission electron microscopy techniques and powder synchrotron X-ray diffraction. Transmission electron microscopy also revealed the (3 + 1)­D incommensurately modulated character of Ag_<i>x</i>Eu³⁺_{(2–<i>x</i>)/3}□_{(1–2<i>x</i>)/3}WO₄ (<i>x</i> = 0.286, 0.2) phases. The crystal structures of the scheelite-based Ag_<i>x</i>Eu³⁺_{(2–<i>x</i>)/3}□_{(1–2<i>x</i>)/3}WO₄ (<i>x</i> = 0.5, 0.286, 0.2) red phosphors have been refined from high resolution synchrotron powder X-ray diffraction data. The luminescence properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of Ag_<i>x</i>Eu³⁺_{(2–<i>x</i>)/3}□_{(1–2<i>x</i>)/3}WO₄ (<i>x</i> = 0.5, 0.286, 0.2) phosphors show the strongest absorption at 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The excitation spectra of the Eu_2/3□_1/3WO₄ and Gd_0.367Eu_0.30□_1/3WO₄ phases exhibit the highest contribution of the charge transfer band at 250 nm and thus the most efficient energy transfer mechanism between the host and the luminescent ion as compared to direct excitation. The emission spectra of all samples indicate an intense red emission due to the ⁵D₀ → ⁷F₂ transition of Eu³⁺. Concentration dependence of the ⁵D₀ → ⁷F₂ emission for Ag_<i>x</i>Eu_{(2–<i>x</i>)/3}□_{(1–2<i>x</i>)/3}WO₄ samples differs from the same dependence for the earlier studied Na_<i>x</i>Eu³⁺_{(2–<i>x</i>)/3}□_{(1–2<i>x</i>)/3}MoO₄ (0 ≤ <i>x</i> ≤ 0.5) phases. The intensity of the ⁵D₀ → ⁷F₂ emission is reduced almost 7 times with decreasing <i>x</i> from 0.5 to 0, but it practically does not change in the range from <i>x</i> = 0.286 to <i>x</i> = 0.200. The emission spectra of Gd-containing samples show a completely different trend as compared to only Eu-containing samples. The Eu³⁺ emission under excitation of Eu³⁺(⁵L₆) level (λ_ex = 395 nm) increases more than 2.5 times with the increasing Gd³⁺ concentration from 0.2 (<i>x</i> = 0.5) to 0.3 (<i>x</i> = 0.2) in the Ag_<i>x</i>Gd_{(2−<i>x</i>)/3−0.3}Eu³⁺_0.3□_{(1−2<i>x</i>)/3}WO₄, after which it remains almost constant for higher Gd³⁺ concentrations