The Hanle Effect in 1D, 2D and 3D

This paper addresses the problem of scattering line polarization and the Hanle effect in one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) media for the case of a two-level model atom without lower-level polarization and assuming complete frequency redistribution. The theoretical framework chosen for its formulation is the QED theory of Landi Degl'Innocenti (1983), which specifies the excitation state of the atoms in terms of the irreducible tensor components of the atomic density matrix. The self-consistent values of these density-matrix elements is to be determined by solving jointly the kinetic and radiative transfer equations for the Stokes parameters. We show how to achieve this by generalizing to Non-LTE polarization transfer the Jacobi-based ALI method of Olson et al. (1986) and the iterative schemes based on Gauss-Seidel iteration of Trujillo Bueno and Fabiani Bendicho (1995). These methods essentially maintain the simplicity of the Lambda-iteration method, but their convergence rate is extremely high. Finally, some 1D and 2D model calculations are presented that illustrate the effect of horizontal atmospheric inhomogeneities on magnetic and non-magnetic resonance line polarization signals.Comment: 14 pages and 5 figure

Measuring the Polarization of Boosted Hadronic Tops

We propose a new technique for measuring the polarization of hadronically decaying boosted top quarks. In particular, we apply a subjet-based technique to events where the decay products of the top are clustered within a single jet. The technique requires neither b-tagging nor W-reconstruction, and does not rely on assumptions about either the top production mechanism or the sources of missing energy in the event. We include results for various new physics scenarios made with different Monte Carlo generators to demonstrate the robustness of the technique.Comment: v2: version accepted for publication in JHE

Top Quarks as a Window to String Resonances

We study the discovery potential of string resonances decaying to $t\bar{t}$ final state at the LHC. We point out that top quark pair production is a promising and an advantageous channel for studying such resonances, due to their low Standard Model background and unique kinematics. We study the invariant mass distribution and angular dependence of the top pair production cross section via exchanges of string resonances. The mass ratios of these resonances and the unusual angular distribution may help identify their fundamental properties and distinguish them from other new physics. We find that string resonances for a string scale below 4 TeV can be detected via the $t\bar{t}$ channel, either from reconstructing the $t\bar{t}$ semi-leptonic decay or recent techniques in identifying highly boosted tops.Comment: 22 pages, 6 figure

Heavy Squarks at the LHC

The LHC, with its seven-fold increase in energy over the Tevatron, is capable of probing regions of SUSY parameter space exhibiting qualitatively new collider phenomenology. Here we investigate one such region in which first generation squarks are very heavy compared to the other superpartners. We find that the production of these squarks, which is dominantly associative, only becomes rate-limited at mSquark > 4(5) TeV for L~10(100) fb-1. However, discovery of this scenario is complicated because heavy squarks decay primarily into a jet and boosted gluino, yielding a dijet-like topology with missing energy (MET) pointing along the direction of the second hardest jet. The result is that many signal events are removed by standard jet/MET anti-alignment cuts designed to guard against jet mismeasurement errors. We suggest replacing these anti-alignment cuts with a measurement of jet substructure that can significantly extend the reach of this channel while still removing much of the background. We study a selection of benchmark points in detail, demonstrating that mSquark= 4(5) TeV first generation squarks can be discovered at the LHC with L~10(100)fb-1

A novel isolator-based system promotes viability of human embryos during laboratory processing

In vitro fertilisation (IVF) and related technologies are arguably the most challenging of all cell culture applications. The starting material is a single cell from which one aims to produce an embryo capable of establishing a pregnancy eventually leading to a live birth. Laboratory processing during IVF treatment requires open manipulations of gametes and embryos, which typically involves exposure to ambient conditions. To reduce the risk of cellular stress, we have developed a totally enclosed system of interlinked isolator-based workstations designed to maintain oocytes and embryos in a physiological environment throughout the IVF process. Comparison of clinical and laboratory data before and after the introduction of the new system revealed that significantly more embryos developed to the blastocyst stage in the enclosed isolator-based system compared with conventional open-fronted laminar flow hoods. Moreover, blastocysts produced in the isolator-based system contained significantly more cells and their development was accelerated. Consistent with this, the introduction of the enclosed system was accompanied by a significant increase in the clinical pregnancy rate and in the proportion of embryos implanting following transfer to the uterus. The data indicate that protection from ambient conditions promotes improved development of human embryos. Importantly, we found that it was entirely feasible to conduct all IVF-related procedures in the isolator-based workstations

Interplay between Fermi gamma-ray lines and collider searches

We explore the interplay between lines in the gamma-ray spectrum and LHC searches involving missing energy and photons. As an example, we consider a singlet Dirac fermion dark matter with the mediator for Fermi gamma-ray line at 130 GeV. A new chiral or local U(1) symmetry makes weak-scale dark matter natural and provides the axion or Z 0 gauge boson as the mediator connecting between dark matter and electroweak gauge bosons. In these models, the mediator particle can be produced in association with a monophoton at colliders and it produces large missing energy through the decays into a DM pair or ZZ; Z with at least one Z decaying into a neutrino pair. We adopt the monophoton searches with large missing energy at the LHC and impose the bounds on the coupling and mass of the mediator field in the models. We show that the parameter space of the Z 0 mediation model is already strongly constrained by the LHC 8TeV data, whereas a certain region of the parameter space away from the resonance in axion-like mediator models are bounded. We foresee the monophoton bounds on the Z 0 and axion mediation models at the LHC 14 TeV

Analysis of dental care of children receiving comprehensive care under general anaesthesia at a teaching hospital in England

Objectives: This study aimed to analyse the characteristics of comprehensive dental care provided under general anaesthesia (CDGA) and to review the additional treatment required by children over the 6 years subsequent to CDGA. Method: Information collected from hospital records for the 6-year period following the first CDGA included the types of dental treatment performed at CDGA, the return rates for follow-up appointments, further treatment required subsequent to CDGA and the types of dental treatment performed at repeat DGA. Results: The study population consisted of 263 children, of whom 129 had a significant medical history, with mean age of 6.7 years. The results revealed that the waiting time for CDGA was significantly shorter in children who had a significant medical history, with 49 % being admitted for CDGA within 3 months of pre-GA assessment, as compared to 29 % of healthy children. 67 % of children had follow-up care recorded, with a slightly higher proportion of children with significant medical history returning for follow-up [70 % (90/129)] compared with 65 % (87/134) of healthy children. Re-treatment rates were 34 % (88/263), the majority of cases being treated under local analgesia (42/88). 34 of 263 children had repeat DGA (12.9 %). Of these 71 % (24/34) were children with significant medical history. The mean age at repeat DGA was 9 years. In 25 of 34 children (74 %), repeat DGA was due to trauma, oral pathology, supernumerary removal, hypomineralized teeth or new caries of previously sound or un-erupted teeth at CDGA. The ratio of extraction over restoration (excluding fissure sealants) performed at repeat DGA was 2.8, compared with the ratio of 1.3 in the initial CDGA. Conclusions: There was a higher ratio of extraction over restorations at the repeat DGA. This suggests that the prescribed treatments at repeat DGA were more aggressive as compared to the initial CDGA in 1997. The majority of the treatment required at repeat DGA was to treat new disease

Overview on the phenomenon of two-qubit entanglement revivals in classical environments

The occurrence of revivals of quantum entanglement between separated open quantum systems has been shown not only for dissipative non-Markovian quantum environments but also for classical environments in absence of back-action. While the phenomenon is well understood in the first case, the possibility to retrieve entanglement when the composite quantum system is subject to local classical noise has generated a debate regarding its interpretation. This dynamical property of open quantum systems assumes an important role in quantum information theory from both fundamental and practical perspectives. Hybrid quantum-classical systems are in fact promising candidates to investigate the interplay among quantum and classical features and to look for possible control strategies of a quantum system by means of a classical device. Here we present an overview on this topic, reporting the most recent theoretical and experimental results about the revivals of entanglement between two qubits locally interacting with classical environments. We also review and discuss the interpretations provided so far to explain this phenomenon, suggesting that they can be cast under a unified viewpoint.Comment: 16 pages, 9 figures. Chapter written for the upcoming book "Lectures on general quantum correlations and their applications

Expression of M. tuberculosis-induced suppressor of cytokine signaling (SOCS) 1, SOCS3, FoxP3 and secretion of IL-6 associates with differing clinical severity of tuberculosis

Background Appropriate immune activation of T cells and macrophages is central for the control of Mycobacterium tuberculosis infections. IFN-γ stimulated responses are lowered in tuberculosis (TB), while expression of Suppressor of Cytokine Signaling (SOCS) molecules – 1 and 3 and CD4+CD25+FoxP3+T regulatory cells is increased. Here we investigated the association of these molecules in regard to clinical severity of TB. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from patients with pulmonary TB (PTB, n = 33), extra-pulmonary TB (ETB, n = 33) and healthy endemic controls (EC, n = 15). Cases were classified as moderately advanced or far advanced PTB, and less severe or severe disseminated ETB. M. tuberculosis -stimulated IFN-γ, SOCS1, SOCS3 and FoxP3 gene expression and secretion of Th1 and Th2 cytokines was measured. Statistical analysis was performed using Mann–Whitney U, Wilcoxon Rank and Kruskal Wallis non-parametric tests. Results In un-stimulated PBMCs, IL-6 (p = 0.018) and IL-10 (p = 0.013) secretion levels were increased in PTB while IL-10 was also increased in ETB (p = 0.003), all in comparison with EC. M. tuberculosis-stimulated IL-6 (p = 0.003) was lowered in ETB as compared with EC. SOCS1 mRNA expression in M. tuberculosis stimulated PBMCs levels in moderately advanced PTB (p = 0.022), far advanced (p = 0.014) PTB, and severe ETB (p = 0.009) were raised as compared with EC. On the other hand, SOCS1 mRNA titers were reduced in less severe ETB, in comparison with severe ETB (p = 0.027) and far advanced PTB (p = 0.016). SOCS3 mRNA accumulation was reduced in far advanced PTB (p = 0.007) and FoxP3 mRNA expression was increased in less severe ETB as compared with EC (p = 0.017). Conclusions The lowered SOCS1 mRNA levels in patients with less severe extra-pulmonary TB as compared to those with more severe ETB and PTB may lead to elevated IFN-γ pathway gene expression in the latter group. As localized ETB has shown to be associated with more effective Th1 immunity and adaptive responses, this suggests a role for SOCS1 in determining disease outcome in extra-pulmonary TB