Role of CD8 T cell subsets in the pathogenesis of multiple sclerosis

AbstractMultiple sclerosis (MS) is an immune-mediated disease of the central nervous system leading to demyelination and axonal/neuronal loss. Cumulating evidence points to a key role for CD8 T cells in this disabling disease. Oligoclonal CD8 T cells reside in demyelinating plaques where they are likely to contribute to tissue destruction. Histopathological analyses and compelling observations from animal models indicate that cytotoxic CD8 T cells target neural cell populations with the potential of causing lesions reminiscent of MS. However, CD8 T cell differentiation results in several subsets of effector CD8 T cells that could be differentially implicated in the mechanisms contributing to tissue damage. Moreover CD8 regulatory T cells arise as important populations involved in restoring immune homoeostasis and in maintaining immune privileged sites. Here we examine the current literature pertaining to the role of CD8 effector and regulatory T cell subsets in the pathogenesis of MS

Limits on the Ununified Standard Model

The ununified standard model is an extension of the standard model that contains separate electroweak gauge groups for quarks and leptons. When it was originally proposed, data allowed the new gauge bosons to be quite light. We use recent data from precision electroweak measurements to put stringent bounds on the ununified standard model. In particular, at the 95% confidence level, we find that the ununified gauge bosons must have masses above about 2 TeV.Comment: 14 pages, plain TeX, 2 postscript figures, figures also available at http://smyrd.bu.edu/htfigs/figure.htm

Political Dynasties and the Selection of Cabinet Ministers

We investigate whether politicians whose family relatives previously served in parliament and cabinet enjoy a competitive "legacy advantage" in progressing from the backbenches to ministerial office. This advantage may stem from two potential mechanisms: a direct effect attributable to the informational advantages of legacies, or an indirect effect that operates through greater electoral strength. We evaluate the relative contribution of each mechanism using candidate-level data from Irish parliamentary elections and cabinets from 1944-2016. Our results reveal that politicians with a family history in cabinet do enjoy an advantage in cabinet selection, and that this advantage cannot be attributed simply to greater electoral popularity

R-Parity Violation at HERA ?

We examine the possibility that the high-Q^2 events seen at HERA are due to the production and decay of squarks of R-parity violating supersymmetry. The relevant R-parity violating coupling(s) is identified and shown to lie between 0.03 and 0.26. Consequences of such a coupling at other experiments, such as the LEP and Tevatron, are discussed

Weighted Gossip: Distributed Averaging Using Non-Doubly Stochastic Matrices

This paper presents a general class of gossip-based averaging algorithms, which are inspired from Uniform Gossip [1]. While Uniform Gossip works synchronously on complete graphs, weighted gossip algorithms allow asynchronous rounds and converge on any connected, directed or undirected graph. Unlike most previous gossip algorithms [2]–[6], Weighted Gossip admits stochastic update matrices which need not be doubly stochastic. Double-stochasticity being very restrictive in a distributed setting [7], this novel degree of freedom is essential and it opens the perspective of designing a large number of new gossip-based algorithms. To give an example, we present one of these algorithms, which we call One-Way Averaging. It is based on random geographic routing, just like Path Averaging [5], except that routes are one way instead of round trip. Hence in this example, getting rid of double stochasticity allows us to add robustness to Path Averaging

Characterising the magnetic fields of the Herbig Ae/Be stars HD97048, HD150193, HD176386, and MWC480

Our knowledge of the presence and the role of magnetic fields in intermediate-mass pre-main-sequence stars remains very poor. We present the magnetic properties of four Herbig Ae/Be stars that have not been previously studied in detail. Our results for the three Herbig Ae/Be stars HD97048, HD150193, and HD176386 are based on multi-epoch low-resolution spectra obtained in spectropolarimetric mode with FORS2 mounted on the VLT. New high-resolution polarimetric spectra were obtained for MWC480 with the SOFIN spectrograph installed at the Nordic Optical Telescope. We discuss 41 FORS2 low-resolution observations of the Herbig Ae/Be stars HD97048, HD150193, and HD176386 and determine their rotational periods. Using stellar fundamental parameters and the longitudinal magnetic field phase curves, we place constraints on the magnetic field geometry. Three high-resolution circularly polarised SOFIN spectra obtained for MWC480 were measured using the moment technique where wavelength shifts between right- and left-hand side circularly polarised spectra are interpreted in terms of a longitudinal magnetic field . Our search for periodicities resulted in P=0.693d for HD97048, P=1.317d for HD150193, and P=0.899d for HD176386. The magnetic field geometry can likely be described by a centred dipole with a polar magnetic field strength B_d of several hundred Gauss. The longitudinal magnetic-field measurements of MWC480 reveal the presence of a strong kG field, which was undetected in our previous low-resolution polarimetric observations with FORS1. A weak magnetic field was detected in the circumstellar components of the Ca II H&K lines and the Na I D lines, indicating a complex interaction between the stellar magnetic field and the circumstellar environment.Comment: 8 pages, 9 figures, 5 tables, accepted for publication in A&

Auto - incompatibilidad, parámetros florales y caracterización de polen en la especie endémica y amenazada Artemisia granatensis (Asteraceae)

Artemisia granatensis Boiss. is a paradigmatic species for plant conservation in Spain and Europe. It is a critically endangered (CR) endemic species growing above 2500 m in the Sierra Nevada (southern Spain). Natural populations have been considerably devastated in the past due to intensive human exploitation for folk medicine. The sparse available data concerning the reproductive biology of this species under natural conditions indicate a low reproductive success. To provide additional information on the reproductive biology of A. granatensis, and consequently information useful for the management and conservation of this species, we studied the breeding system through pollen-tube growth. In addition, some floral and pollen traits were recorded. No differences were found between populations in terms of the morphological traits of flowers and inflorescences. A. granatensis is an anemophilous species, and the data indicate that pollen transfer may be limited between isolated populations, and so contributing to an extremely low fruit-set. Results show A. granatensis is selfincompatible, probably with a sporophytic self-incompatibility system, and with no evidence of partial self-incompatibility. Reproductive traits, related to pollen morphology and settling speed may explain the low rate of recruitment in the small populations separated by geographical barriers.Artemisia granatensis Boiss. es una especie paradigmática en la conservación de flora a nivel español y europeo. Es una especie catalogada como En Peligro Crítico (CR) endémica de Sierra Nevada (sur de España), donde habita por encima de los 2500 m. Las poblaciones naturales han sido casi exterminadas en el pasado debido a una recolección masiva de la especie, utilizada en medicina popular. Los escasos datos disponibles acerca de su biología reproductiva en condiciones naturales indican que existe un bajo éxi to reproductivo. Con el objetivo de proporcionar información adicional acerca de la biología reproductiva de A. granatensis, útil para la conservación y el manejo de la especie, evaluamos el sistema de compatibilidad a través del crecimiento del tubo polínico. Además se registraron datos sobre algunos rasgos florales y polínicos de la especie. No se encontraron diferencias entre poblaciones en términos de rasgos morfológicos de flores e inflorescencias. A. granatensis es una especie anemófila para la cual los datos obtenidos sobre capacidad de dispersión sugieren que la transferencia de polen podría ser difícil entre poblaciones aisladas o muy distanciadas, pudiendo ser un factor más a tener en cuenta entre las causas que provocan un limitado éxito reproductivo y una paupérrima producción de semillas. Los resultados muestran que A. granatensis tiene autoincompatibilidad esporofítica sin evidencias de autoincompatibilidad parcial. Los rasgos reproductivos relacionados con la morfología y la velocidad de sedimentación del polen pueden explicar la baja tasa de reclutamiento de poblaciones pequeñas, a veces separadas por barreras geográficas.This work has been partly financed by the Spanish Education and Science Ministry (project reference REN2003-09427-C02), and partly by the Consejería de Innovación, Ciencia y Tecnología de la Junta de Andalucía (project reference P05-RNM1067)

Precision tests of the MSSM

We present the results of a first global fit to the electroweak observables in the MSSM. The best fit selects either very low or very large values of ~$\tan\beta$ ~and, correspondingly, chargino (higgsino--like) and stop or the ~$CP-$odd Higgs boson are within the reach of LEP 2. Moreover, the best fit gives ~ $\alpha_s(M_Z)=0.118^{+0.005}_{-0.010}$, ~which is lower than the one obtained from the SM fits. The overall fit is excellent ~ ($\chi^2=7.2$ ~for 15 d.o.f. as compared to ~$\chi^2=11$ ~in the SM). Those results follow from the fact that in the MSSM one can increase the value of ~ $R_b\equiv\Gamma_{Z^0\to\bar bb}/\Gamma_{Z^0\to hadrons}$ ~ {\it without} modyfying the SM predictions for other observables.Comment: 10 pages, LaTEX, 7 figures (not included) may be obtained from [email protected] upon request. Modified version of the plenary talk given by S. Pokorski at the ``Beyond the Standard Model IV'', Lake Tahoe, CA, December 199