Evolution of thymopoietic microenvironments

In vertebrates, the development of lymphocytes from undifferentiated haematopoietic precursors takes place in so-called primary lymphoid organs, such as the thymus. Therein, lymphocytes undergo a complex differentiation and selection process that culminates in the generation of a pool of mature T cells that collectively express a self-tolerant repertoire of somatically diversified antigen receptors. Throughout this entire process, the microenvironment of the thymus in large parts dictates the sequence and outcome of the lymphopoietic activity. In vertebrates, direct genetic evidence in some species and circumstantial evidence in others suggest that the formation of a functional thymic microenvironment is controlled by members of the Foxn1/4 family of transcription factors. In teleost fishes, both Foxn1 and Foxn4 contribute to thymopoietic activity, whereas Foxn1 is both necessary and sufficient in the mammalian thymus. The evolutionary history of Foxn1/4 genes suggests that an ancient Foxn4 gene lineage gave rise to the Foxn1 genes in early vertebrates, raising the question of the thymopoietic capacity of the ancestor common to all vertebrates. Recent attempts to reconstruct the early events in the evolution of thymopoietic tissues by replacement of the mouse Foxn1 gene by Foxn1-like genes isolated from various chordate species suggest a plausible scenario. It appears that the primordial thymus was a bi-potent lymphoid organ, supporting both B cell and T cell development; however, during the course of vertebrate, evolution B cell development was gradually diminished converting the thymus into a site specialized in T cell development

Influence of diagenetic processes and terrestrial/anthropogenic sources in the REE contents of the Cascais submarine canyon (Iberian western coast)

ABSTRACT: Temporal variations of rare earth elements (REE) and their fractionation patterns, major elements, Pb and Hg were determined in two multicores collected at 445 and 2100 m water depth (mwd) in the Cascais submarine canyon (CSC). The PAAS-normalized REE patterns suggest mixing of Tagus estuarine and marine sediments, marked by MREE (Nd‐Dy series) enrichment and by positive Eu-anomaly, with marine sediments. The positive Eu/Eu* implies incorporation of detrital feldspar minerals derived from the estuary. Ce/Ce*, (La/Yb)PAAS and (Nd/Yb)PAAS show differences between the two cores. Core 252-35 from the shallower site is enriched in HREE (Ho‐Lu series) over LREE (La‐Pr series), a pattern also found in the Tagus estuary in the vicinity of an abandoned chemical complex, where the environment is affected by the legacy of massive-sulfide ores processing. There seems to be only limited down-canyon sediment transport to the deeper reaches where core 252-32 was collected. This deeper site shows Ce/Ce* peaks coinciding with low (La/Yb)PAAS values suggesting preferential diagenetic remobilization of LREE relative to HREE. Upcore Pb/Al and Hg/Corg trends observed in both cores indicate dispersion of the anthropogenic component from the estuary through the CSC, which is less obvious from the ∑REE/Al trends particularly in the deeper site. This may suggest the influence of diagenetic processes in the REE signal, associated with relatively low sediment accumulation rates.info:eu-repo/semantics/publishedVersio

Tourism and the city: the impact on residents' quality of life

The present work investigates the relationship between tourism presence and perceptions of urban quality of life of resident populations (UQOL). Nowadays, this topic is at the forefront since many European cities have started raising their voice against mass tourism. An ad hoc questionnaire was designed and submitted to resident population of two Mediterranean destinations. Following an integrative approach à la Sen, UQOL is analysed using the presence of the services/amenities (capabilities) as well as their accessibility (functionings). Findings indicate that both presence and mainly accessibility of services/amenities matter for UQOL and that a negative effect of tourism prevails

RAG Recombinase as a Selective Pressure for Genome Evolution

The RAG recombinase is a domesticated transposable element co-opted in jawed vertebrates to drive the process of the so-called V(D)J recombination, which is the hallmark of the adaptive immune system to produce antigen receptors. RAG targets, namely, the Recombination Signal Sequences (RSS), are rather long and degenerated sequences, which highlights the ability of the recombinase to interact with a wide range of target sequences, including outside of antigen receptor loci. The recognition of such cryptic targets by the recombinase threatens genome integrity by promoting aberrant DNA recombination, as observed in lymphoid malignancies. Genomes evolution resulting from RAG acquisition is an ongoing discussion, in particular regarding the counter-selection of sequences resembling the RSS and the modifications of epigenetic regulation at these potential cryptic sites. Here, we describe a new bioinformatics tool to map potential RAG targets in all jawed vertebrates. We show that our REcombination Classifier (REC) outperforms the currently available tool and is suitable for full genomes scans from species other than human and mouse. Using the REC, we document a reduction in density of potential RAG targets at the transcription start sites of genes co-expressed with the rag genes and marked with high levels of the trimethylation of the lysine 4 of the histone 3 (H3K4me3), which correlates with the retention of functional RAG activity after the horizontal transfer.Instituto Gulbenkian de Ciência; Optimus alive award; Fundação para a Ciência e Tecnologia grant: (SFRH/BPD/65292/2009).info:eu-repo/semantics/publishedVersio

SPA: Web-based platform for easy access to speech processing modules

This paper presents SPA, a web-based Speech Analytics platform that integrates several speech processing modules and that makes it possible to use them through the web. It was developed with the aim of facilitating the usage of the modules, without the need to know about software dependencies and specific configurations. Apart from being accessed by a web-browser, the platform also provides a REST API for easy integration with other applications. The platform is flexible, scalable, provides authentication for access restrictions, and was developed taking into consideration the time and effort of providing new services. The platform is still being improved, but it already integrates a considerable number of audio and text processing modules, including: Automatic transcription, speech disfluency classification, emotion detection, dialog act recognition, age and gender classification, non-nativeness detection, hyperarticulation detection, dialog act recognition, and two external modules for feature extraction and DTMF detection. This paper describes the SPA architecture, presents the already integrated modules, and provides a detailed description for the ones most recently integrated.info:eu-repo/semantics/publishedVersio

Submarine Cascais Canyon as a sediment conduit to the deep sea : comparison with adjacent slopes

Submarine canyons are known to be important conduits that trap, accumulate and deliver both natural and anthropogenic sediments from the shelf to the deep sea. Ten multi-cores from the Cascais Canyon and from the neighbour slopes (off Estremadura and Sines) were dated by 21Opb methodologies and analyzed for texture, major and trace metals to evaluate the role of submarine canyons in the transport of anthropogenic metals to the abyssal plains. Higher accumulation mass rates were determined in the upper Cascais Canyon than in the lower canyon and slopes. Enrichment factors (EF) were used to evaluate the level of metal enrichment in the studied areas. EF values exceeding natural background concentrations were obtained for Pb suggesting an anthropogenic and/or diagenetic source for Pb enrichment in the Cascais Canyon, but also, to a lesser extent, in the Estremadura and Sines slopes. Studies of provenance based on the ratio of different stable Pb isotopes can help to determinethe origin of such metal in the sediments

Alterações recentes nas razões isotópicas de Pb em sedimentos do Canhão Submarino de Cascais, Portugal

Temporal variations in lead concentrations and stable lead isotopic ratios in two sediment cores from the Cascais Canyon shows changes in sources of Pb during the last two centuries. The increase of total Pb contents wIth the evolution of Pb ratio recorded in both cores reveals the Increase of Pb from industrial sources. Nevertheless, this increase is lower in deeper core location (252-32) due to dilution and mixing with uncontaminated marine materials. An isotopic shift towards lower Pb/Pb in the shallower core (252-35) during the 1970s may reflect the increasing number of vehicles in the Lisboa area during that time