421 research outputs found
Human red blood cells have an enhancing effect on the relative expansion of CD8+ T lymphocytes in vitro
Cell Prolif. 2001 Dec;34(6):359-67.
Human red blood cells have an enhancing effect on the relative expansion of CD8+ T lymphocytes in vitro.
Porto B, Fonseca AM, Godinho I, Arosa FA, Porto G.
Laboratory of Cytogenetics, Abel Salazar Institute for the Biomedical Sciences (ICBAS), Porto, Portugal. [email protected]
Abstract
The present study was designed to analyse the effect of red blood cells on T-cell proliferation and expansion. A comparative study was done in peripheral blood cell cultures stimulated with phytohemagglutinin, with or without red blood cells. The presence of red blood cells had a consistent enhancing effect on T lymphocyte proliferation, as determined by an increase in both the mitotic index and thymidine uptake. Phenotypic characterization of T cell blasts by flow cytometry revealed that, in the presence of red blood cells, expanding cells were preferentially CD8+ cells. Accordingly, proliferation of CD8+ lymphocytes from two patients with CD8+ hyperlymphocytosis was dependent on the presence of red blood cells. In contrast, proliferation of CD4+ lymphocytes from two patients with CD4+ hyperlymphocytosis was strongly inhibited by the presence of red blood cells. This is the first reported evidence that human red blood cells have an enhancing effect on the expansion of CD8+ lymphocytes in vitro.
PMID: 11737000 [PubMed - indexed for MEDLINE
Spatial and temporal concentration of tourism demand in northern Portugal: regional policy recommendations to promote tourism competition and portofolio diversity
The northern region of Portugal, in the last years, has experienced a growing number of visitors from different countries, which may indicate the emergence of an overtourism phenomenon in some particular municipalities or specific spaces. This phenomenon may cause significant destruction of the living conditions of residents, landscapes, seascapes, air and water quality, causing economic inequalities and social exclusion. The concentration of tourism activity in different municipality regions can be measured with a well know concentration measured, the Herfindahl-Hirschman Index. Using as variables the number and nationality of visitors and their expenditures it is possible to follow the concentration of tourism visitors and expenditure, all over the 8 NUTIII regions located in the Northen of Portugal, and describe the routes of distribution of the tourism indicators from urban to rural areas following a more nature-oriented tourism. The results serve as a dipping compass for more oriented and well-targeted tourism policies.info:eu-repo/semantics/publishedVersio
First record of anelosimus jucundus (O. Pickard-Cambridge, 1896) (araneae, theridiidae) in the state of Ceara, Brazil
We present the first record for Anelosimus jucundus O. Pickard-Cambridge, 1896 for the state of Ceará, Brazil. We collected 22 individuals in three different ecosystems: (1) Mangrove swamps, (2) Caatinga-type desert vegetation, and (3) Montane semi-deciduous tropical forest. We corrected the misinformation of Levi’s 1963 Ceará record, was actually from the state of Pernambuco. Anelosimus jucundus presents a wide altitudinal distribution, which indicates that this species can tolerate a variety climatic conditions and can colonize a variety of sites with different vegetation155933936CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPnão temnão temnão temThis study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES), Finance Code 001 (G.A. Villanueva-Bonilla). We were also financially supported by the Instituto Na-cional de Ciência e Tecnologia dos Hymenoptera Para-sitoides (HYMPAR/Sudeste – CNPq/FAPESP/CAPES), FUNCAP-BPI proc. BP3- 00139- 00186.01.00/18 (research grants to J.F. Sobczak
Demand and supply of outdoor tourism activities in Northern Portugal: a survey-based approach
This paper focuses on the North of Portugal, as a diversified region with unique natural resources, to create information regarding both resources and equipment and business dynamics; the evolution of tourism supply and demand.This research is a part of a project title “TURNOUT: Desenvolvimento do Turismo Outdoor da Região Norte de
Portugal”, with the reference POCI-01-0145-FEDER-032289; funded by the European Regional Development
Fund (FEDER) (through the Operational Programme ‘Innovation and competitiveness’) and by the Portuguese
Foundation for the Development of Science and Technology (FCT), of the Ministry of Science, Technology and
Higher Education. This work is, also, funded by National Funds through the Foundation for Science and
Technology under the project UIDB/04752/2020. The SABI database was made available by the Applied
Management Research Unit (UNIAG), according to the protocol between UNIAG and COFACE.info:eu-repo/semantics/publishedVersio
Trophic models and short-term dynamic simulations for benthic-pelagic communities at Banco Chinchorro Biosphere Reserve (Mexican Caribbean): a conservation case
Banco Chinchorro is the largest reef in the Mexican Caribbean. Historically, spiny lobster, queen conch and over 20 other reef species have been exploited here. Multispecies intervention management from an ecosystem perspective has been developed in this area; however, an assessment of the effects of such practices on ecosystem health is required. Five quantitative trophic models were constructed using Ecopath with Ecosim. The results show that, in terms of biomass, benthic autotrophs are the dominant group in all communities. Ecosystem Network Analysis indices showed that Cueva de Tiburones was the most mature, developed, complex and healthy subsystem, but, El Colorado and La Baliza were the subsystems most resistant to disturbances. The fisheries mainly concentrate on primary (La Baliza and Cueva de Tiburones sites) and secondary consumers (La Caldera, Chancay, and El Colorado). The greatest propagation of direct and indirect effects, estimated by Mixed Trophic Impacts and Ecosim simulations, were generated by the benthic autotrophs, small benthic epifauna, benthic-pelagic carnivorous fish and benthic carnivorous fish, among others. In contrast, the System Recovery Time showed different patterns among subsystems, indicating several compartments that reduce resilience. Considering the structure, dynamics, trophic functioning and ecosystem health of Banco Chinchorro, its ecological heterogeneity highlights the need for the design of a specific (by subsystem) management strategy, particularly because different species or functional groups present greater sensitivity to human interventions in each community
4D gravity on a non-BPS bent dilatonic brane
We investigate the localization of metastable four-dimensional gravity around
a bent dilatonic brane, embedded into a five-dimensional space, that exists
only up to distances sufficiently small compared to a crossover scale. Far from
such scale, five-dimensional effects strongly deviate the Newtonian potential.
We study this effect by considering localization of massive gravity on a
non-BPS bent dilatonic 3-brane solution of a five-dimensional supergravity. Our
results show that the cosmological constant on the bent brane controls the size
of the crossover scale. For sufficiently small positive cosmological constant,
that is in accord with the present observations, the crossover scale becomes
very large.Comment: 7 pages, version to appear in JCA
Stationary solutions for the parity-even sector of the CPT-even and Lorentz-covariance-violating term of the standard model extension
In this work, we focus on some properties of the parity-even sector of the
CPT-even electrodynamics of the standard model extension. We analyze how the
six non-birefringent terms belonging to this sector modify the static and
stationary classical solutions of the usual Maxwell theory. We observe that the
parity-even terms do not couple the electric and magnetic sectors (at least in
the stationary regime). The Green's method is used to obtain solutions for the
field strengths E and B at first order in the Lorentz- covariance-violating
parameters. Explicit solutions are attained for point-like and spatially
extended sources, for which a dipolar expansion is achieved. Finally, it is
presented an Earth-based experiment that can lead (in principle) to an upper
bound on the anisotropic coefficients as stringent as
Comment: 8 pages, revtex style, revised published version, to appear in EPJC
(2009
Generating mixtures of spatial qubits
In a recent letter [Phys. Rev. Lett. 94, 100501 (2005)], we presented a
scheme for generating pure entangled states of spatial qudits (-dimensional
quantum systems) by using the momentum transverse correlation of the parametric
down-converted photons. In this work we discuss a generalization of this
process to enable the creation of mixed states. With the technique proposed we
experimentally generated a mixture of two spatial qubits.Comment: To appear in Optics Communication
On Dark Matter Annihilation in the Local Group
Under the hypothesis of a Dark Matter composed by supersymmetric particles
like neutralinos, we investigate the possibility that their annihilation in the
haloes of nearby galaxies could produce detectable fluxes of -photons.
Expected fluxes depend on several, poorly known quantities such as the density
profiles of Dark Matter haloes, the existence and prominence of central density
cusps and the presence of a population of sub-haloes. We find that, for all
reasonable choices of Dark Matter halo models, the intensity of the
-ray flux from some of the nearest extragalactic objects, like M31, is
comparable or higher than the diffuse Galactic foreground. We show that next
generation ground-based experiments could have the sensitivity to reveal such
fluxes which could help us unveiling the nature of Dark Matter particles.Comment: 11 pages, 10 figures. Accepted for publication in Phys. Rev. D.;
added a new paragraph on the detectability of Galactic sub-halos in our
Galaxy; added a discussion on their model dependence. The relation of our
results with the "CDM crisis" issue has also been adde
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