37 research outputs found
The role of TNFR2 and DR3 in the in vivo expansion of tregs in T cell depleting transplantation regimens
[EN] Regulatory T cells (Tregs) are essential for the maintenance of tolerance to self and non-self
through cell-intrinsic and cell-extrinsic mechanisms. Peripheral Tregs survival and clonal expansion
largely depend on IL-2 and access to co-stimulatory signals such as CD28. Engagement of tumor
necrosis factor receptor (TNFR) superfamily members, in particular TNFR2 and DR3, contribute to
promote peripheral Tregs expansion and sustain their survival. This property can be leveraged to
enhance tolerance to allogeneic transplants by tipping the balance of Tregs over conventional T cells
during the course of immune reconstitution. This is of particular interest in peri-transplant tolerance
induction protocols in which T cell depletion is applied to reduce the frequency of alloreactive T cells
or in conditioning regimens that allow allogeneic bone marrow transplantation. These conditioning
regimens are being implemented to limit long-term side effects of continuous immunosuppression and
facilitate the establishment of a state of donor-specific tolerance. Lymphopenia-induced homeostatic
proliferation in response to cytoreductive conditioning is a window of opportunity to enhance
preferential expansion of Tregs during homeostatic proliferation that can be potentiated by agonist
stimulation of TNF
Quick decline and stem pitting Citrus tristeza virus isolates induce a distinct metabolomic profile and antioxidant enzyme activity in the phloem sap of two Citrus species
Susceptibility to the severe Citrus tristeza virus (CTV), T36, is higher for Citrus macrophylla
(CM) than for C. aurantium (CA). How host-virus interactions are reflected in host physiology is
largely unknown. In this study, the profile of metabolites and the antioxidant activity in the phloem
sap of healthy and infected CA and CM plants were evaluated. The phloem sap of quick decline
(T36) and stem pitting (T318A) infected citrus, and control plants was collected by centrifugation,
and the enzymes and metabolites analyzed. The activity of the antioxidant enzymes, superoxide
dismutase (SOD) and catalase (CAT), in infected plants increased significantly in CM and decreased
in CA, compared to the healthy controls. Using LC-HRMS2 a metabolic profile rich in secondary
metabolites was assigned to healthy CA, compared to healthy CM. CTV infection of CA caused a
drastic reduction in secondary metabolites, but not in CM. In conclusion, CA and CM have a different
response to severe CTV isolates and we propose that the low susceptibility of CA to T36 may be
related to the interaction of the virus with the host’s metabolism, which reduces significantly the
synthesis of flavonoids and antioxidant enzyme activity.ALG-01-0145-FEDER-30957; LA/P/0101/2020; ALG-01-0145-FEDER-022121info:eu-repo/semantics/publishedVersio
A high performance cost-effective digital complex correlator for an X-band polarimetry survey
The detailed knowledge of the Milky Way radio emission is important to characterize galactic foregrounds masking extragalactic and cosmological signals. The update of the global sky models describing radio emissions over a very large spectral band requires high sensitivity experiments capable of observing large sky areas with long integration times. Here, we present the design of a new 10 GHz (X-band) polarimeter digital back-end to map the polarization components of the galactic synchrotron radiation field of the Northern Hemisphere sky. The design follows the digital processing trends in radio astronomy and implements a large bandwidth (1 GHz) digital complex cross-correlator to extract the Stokes parameters of the incoming synchrotron radiation field. The hardware constraints cover the implemented VLSI hardware description language code and the preliminary results. The implementation is based on the simultaneous digitized acquisition of the Cartesian components of the two linear receiver polarization channels. The design strategy involves a double data rate acquisition of the ADC interleaved parallel bus, and field programmable gate array device programming at the register transfer mode. The digital core of the back-end is capable of processing 32 Gbps and is built around an Altera field programmable gate array clocked at 250 MHz, 1 GSps analog to digital converters and a clock generator. The control of the field programmable gate array internal signal delays and a convenient use of its phase locked loops provide the timing requirements to achieve the target bandwidths and sensitivity. This solution is convenient for radio astronomy experiments requiring large bandwidth, high functionality, high volume availability and low cost. Of particular interest, this correlator was developed for the Galactic Emission Mapping project and is suitable for large sky area polarization continuum surveys. The solutions may also be adapted to be used at signal processing subsystem levels for large projects like the square kilometer array testbeds
The preservation of significant Islamic architectural heritage of Al-Mustansiriya School, Baghdad City, Iraq
Baghdad City is distinguished by its rich Islamic architectural heritage. Deterioration of heritage building values can affect the city itself as well as the country in general.This research highlights the issue that Al-Mustansiriya School, located in Baghdad City, is facing. There is no attention from local population neither governmental protection to its architectural heritage values. Therefore, there is a dire need to preserve the heritage school, aiming to increase not just tourism to the city, but also to the entire country. After the introduction of the background problem, this research presents the existing literature on Al-Mustansiriya School, highlighting the significant historical values, then summarizing the issues that it is facing. The methodology of this research uses a case study, following a qualitative method. This study contributes to the identification of the significant architectural element values of the place, proposing a theory on the protection of Islamic Architecture Heritage from the issues that Al-Mustansiriya in Baghdad City is facing and high-lights the important role of local organizations and archaeologists in preservation of heritage sites, with its recommendations. It helps on the protection and documentation of heritage values in Al-Mustansiriya, having a global impact towards humanity issues
Searching for non-Gaussianity in the VSA data
We have tested Very Small Array (VSA) observations of three regions of sky
for the presence of non-Gaussianity, using high-order cumulants, Minkowski
functionals, a wavelet-based test and a Bayesian joint power
spectrum/non-Gaussianity analysis. We find the data from two regions to be
consistent with Gaussianity. In the third region, we obtain a 96.7% detection
of non-Gaussianity using the wavelet test. We perform simulations to
characterise the tests, and conclude that this is consistent with expected
residual point source contamination. There is therefore no evidence that this
detection is of cosmological origin. Our simulations show that the tests would
be sensitive to any residual point sources above the data's source subtraction
level of 20 mJy. The tests are also sensitive to cosmic string networks at an
rms fluctuation level of (i.e. equivalent to the best-fit observed
value). They are not sensitive to string-induced fluctuations if an equal rms
of Gaussian CDM fluctuations is added, thereby reducing the fluctuations due to
the strings network to rms . We especially highlight the usefulness
of non-Gaussianity testing in eliminating systematic effects from our data.Comment: Minor corrections; accepted for publication to MNRA
Estimating 3-Dimensional Structure of Tropical Forests from Radar Interferometry / Estimativa da Estrutura 3-Dimensional das Florestas Tropicais Através de Interferometria de Radar
This paper describes the retrieval of 3-dimensional vegetation density profiles from interferometric synthetic aperture radar (InSAR) using physical models. InSAR’s sensitivity to vertical structure is generally regarded as less direct and more difficult to understand than that of lidar. But InSAR’s coverage is superior to that of lidar, suggesting InSAR is more promising as an important component of a global 3-dimensional forest monitoring technique. The goal of this paper is to introduce, simplify and demystify the use of simple physical models to understand InSAR. A general equation expressing the InSAR observation in terms of density is described heuristically, along with the approximations in its development. The information content of the equation leads to the estimation of density parameters. Preliminary results are shown from a multibaseline C-band (wavelength=0.056 m) vertical-polarization interferometer, realized with AirSAR flown at multiple altitudes over primary, secondary, and selectively logged tropical forests, as well as abandoned pastures at La Selva Biological Station in Costa Rica
CMB observations from the CBI and VSA: A comparison of coincident maps and parameter estimation methods
We present coincident observations of the Cosmic Microwave Background (CMB)
from the Very Small Array (VSA) and Cosmic Background Imager (CBI) telescopes.
The consistency of the full datasets is tested in the map plane and the Fourier
plane, prior to the usual compression of CMB data into flat bandpowers. Of the
three mosaics observed by each group, two are found to be in excellent
agreement. In the third mosaic, there is a 2 sigma discrepancy between the
correlation of the data and the level expected from Monte Carlo simulations.
This is shown to be consistent with increased phase calibration errors on VSA
data during summer observations. We also consider the parameter estimation
method of each group. The key difference is the use of the variance window
function in place of the bandpower window function, an approximation used by
the VSA group. A re-evaluation of the VSA parameter estimates, using bandpower
windows, shows that the two methods yield consistent results.Comment: 10 pages, 6 figures. Final version. Accepted for publication in MNRA
Estimating 3-Dimensional Structure of Tropical Forests from Radar InterferometryEstimativa da Estrutura 3-Dimensional das Florestas Tropicais Através de Interferometria de Radar
This paper describes the retrieval of 3-dimensional vegetation density profiles from interferometric synthetic aperture radar (InSAR) using physical models. InSAR’s sensitivity to vertical structure is generally regarded as less direct and more difficult to understand than that of lidar. But InSAR’s coverage is superior to that of lidar, suggesting InSAR is more promising as an important component of a global 3-dimensional forest monitoring technique. The goal of this paper is to introduce, simplify and demystify the use of simple physical models to understand InSAR. A general equation expressing the InSAR observation in terms of density is described heuristically, along with the approximations in its development. The information content of the equation leads to the estimation of density parameters. Preliminary results are shown from a multibaseline C-band (wavelength=0.056 m) vertical-polarization interferometer, realized with AirSAR flown at multiple altitudes over primary, secondary, and selectively logged tropical forests, as well as abandoned pastures at La Selva Biological Station in Costa Rica.Resumo Este trabalho descreve o procedimento de recuperação do perfil tridimensional da densidade de vegetação, a partir de dados interferométricos de radar de abertura sintética (InSAR), utilizando modelos físicos. A sensibilidade da técnica InSAR para detectar estruturas verticais de vegetação é geralmente considerada menos direta e mais difícil de entender se comparado com dados de LIDAR (técnica utilizando laser). A utilização da técnica InSAR permite uma cobertura superior ao LIDAR e é potencialmente mais promissora como técnica de monitoramento global para a detecção da estrutura tri-dimensional de florestas. O objetivo deste trabalho é o de simplificar e desmistificar o uso de modelos físicos simples no entendimento da técnica InSAR. A equação geral que expressa a observação InSAR em termos de densidade é escrita heuristicamente, bem como as aproximações feitas no seu desenvolvimento. O conteúdo de informação da equação nos possibilita a estimação dos parâmetros de densidade da vegetação
A Global Assessment of the Effects of Eucalyptus Plantations on Stream Ecosystem Functioning
Forest change is a major environmental problem worldwide. Forest streams, with their large aquatic–terrestrial interface and strong dependence on terrestrially derived organic matter, are highly sensitive to forest changes. Fast-wood plantations can be particularly threatening if they markedly differ from native forests. Eucalyptus plantations, in particular, cover large areas worldwide (> 20 million ha, mostly from 35°S to 35°N), but their effects on stream functioning have been addressed mostly in the Iberian Peninsula, which limits generalization to other regions. We assessed the effect of eucalyptus plantations on total (microbial decomposers and macroinvertebrates; in coarse mesh bags) and microbial-driven (in fine mesh bags) leaf litter decomposition by comparing streams flowing through native forests and eucalyptus plantations in seven regions in the Iberian Peninsula, Central Africa and South America. We found an overall significant inhibition of total litter decomposition by 23%. The effect did not significantly differ across regions, although a significant inhibition was found for Spain (− 41%), South Brazil (− 31%) and Uruguay (− 36%) (Portugal had a marginally nonsignificant inhibition by 50%) but not for other regions, suggesting that the effects of plantations in temperate climates are mediated through effects on macroinvertebrate communities. Contrarily, the overall effect for microbial-driven litter decomposition was non-significant, but it significantly differed across regions with a significant stimulation in Central Brazil (110%) and Uruguay (32%), and nonsignificant effects for other regions (Kenya had a marginally nonsignificant inhibition by 48%), suggesting that functional redundancy among microbial communities is not general and effects can occur if plantations induce changes in nutrient availability, solar irradiation or litter characteristics