125 research outputs found
Transcorrência diacrônica Cenozóica no sudoeste da Bacia Colombiana
We propose a major Eocene tectonic inversion related to an oblique convergence between Farallon (after Cocos plate) and Caribbean plates in the offshore of Colombian Caribbean. Between EoceneOligocene occurred an extension and another tectonic inversion since Oligocene to Pleistocene. By structural and stratigraphic evidence extracted from seismic, gravity and well data, we identified diverse diachronic Cenozoic deformations related to an important syndepositional wrenching event. Diachronic wrench system corresponds with Riedel structures and subordinated related-structures which have been growing progressively from north to south as result of convergence of Farallon (after Cocos plate) and Caribbean plates. Older basement-involved structures were inverted since Eocene. Tectonic inversions were interpreted from different strata geometries, relations of strata, growth strata and erosive truncations. A regional Eocene unconformity defined by erosional truncations reveals the timing of tectonic inversion and consequently closure of Colombian basin at northern boundary. The Eocene erosional unconformity becomes conformable toward the basin and should be an important correlative stratigraphic surface in the Caribbean offshore.Propõe-se que uma inversão tectónica maior tenha ocorrido durante o Eocénico associada à convergência oblíqua entre as placas Farallon (actual placa de Cocos) e Caribe no offshore do Caribe Colombiano. No período Eocénico-Oligocénico ocorreu extensão e do Oligocénico ao Pleistocénico ocorreu outra inversão tectónica. Foram ainda identificados diferentes eventos de deformação diacrónica no Cenozóico a partir de evidências estruturais e estratigráficas obtidas a partir de dados sísmicos, gravimétricos e de poço. As diferentes deformações estão associadas a um importante evento de transcorrência sin-deposicional. O sistema de transcorrência diacrónica é evidenciado em estruturas riedel e outras subordinadas que se desenvolveram progressivamente de norte para sul no seguimento da convergência das placas Farallon e Caribe. As estruturas antigas que afectaram o substrato foram invertidas a partir do Eocénico. As inversões tectónicas foram interpretadas a partir das diferentes relações geométricas dos estratos. A discordância regional eocénica, identificada a partir de superfícies erosivas, revela o período da inversão tectónica associada ao fecho da Bacia Colombiana no limite norte. A discordância erosiva do Eocénico passa a conformidade à medida que tende para o interior da bacia e deve ser uma importante superfície estratigráfica de correlação no offshore do Caribe.Fil: Alfaro, E.. Universidade Federal Da Bahia; BrasilFil: Barrera, Daniel Florencio. Universidade Estadual de Campinas; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rossello, Eduardo Antonio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Vegetation groups and habitats of neutro-basophilous fens in the Cantabro- Pyrenaean mountains
Los tremedales neutro-basófilos figuran entre los humedales con mayor riqueza de especies y más amenazados de Europa. Debido a su variabilidad ecológica y florística, la vegetación de estos hábitats puede estar sujeta a clasificaciones discordantes. En este trabajo utilizamos una base de datos de tremedales pirenaico-cantábricos para analizar los principales grupos de vegetación de estos medios y su relación con los tipos de hábitat europeos y la clasificación fitosociológica. Seleccionamos 295 muestras de acuerdo a la presencia de plantas higrófilas y calcícolas en el área de estudio (Carex lepidocarpa, C. davalliana, C. frigida y Eriophorum latifolium) y una estratificación espacial. Realizamos una clasificación utilizando datos sobre plantas vasculares y el sistema TWINSPAN modificado con una selección óptima de grupos. Analizamos los grupos de vegetación a partir de su distribución geográfica, variabilidad en altitud y pendiente, así como la similitud en la composición de especies mediante análisis de gradiente (DCA). Identificamos así cinco grupos relacionados con (i) tremedales de fuentes carbonatadas pirenaicas; (ii) fuentes carbonatadas cantábricas con el endemismo Centaurium somedanum; (iii) pastizales húmedos carbonatados pirenaico-cantábricos; (iv) tremedales carbonatados pirenaico-cantábricos; y (v) tremedales neutro-basófilos pirenaicos.Neutro-basophilous fens are among the most species-rich and threatened wetlands in Europe. Because of their ecological and floristic variability, vegetation of these habitats may be subject to classification inconsistencies. Here we use a vegetation database of Cantabro-Pyrenean fens to analyze the main vegetation groups related to these fens and their relationship with the European habitat types and phytosociological classification. We selected 295 vegetation relevés from the study area according to the presence of four calcicole specialists (Carex lepidocarpa, C. davalliana, C. frigida and Eriophorum latifolium) and geographical stratification. We classified the relevés using cover data of vascular plants, modified TWINSPAN analysis and classification crispness. We analyzed the vegetation groups according to their geographical distribution, variation in altitude and slope, and similarity of species composition using gradient analysis (DCA). We finally established five major vegetation groups: (i) Pyrenean calcareous spring fens related to high mountain streamsides, including Caricion davallianae communities with Carex frigida and relict plant communities of the Caricion maritimae alliance; (ii) Cantabrian calcareous springs with the endemic Centaurium somedanum and few fen species, which should be better assigned to tufa-forming springs; (iii) Pyreneo-Cantabrian calcareous fen grasslands, which could be included in alkaline fens or Molinietalia wet grasslands; (iv) Pyreneo-Cantabrian calcareous fens, possibly related to limestone bedrocks of Cantabrian Range and Western Pyrenees; and (v) Pyrenean neutro-basophilous fens, which seem to be part of extremely rich fens distributed on non-limestone substrates of Central and Eastern Pyrenees
Germination ecology of the perennial Centaurium somedanum, a specialist species of mountain springs
To improve understanding of how a rare endemic species of Centaurium adapts to a specialized ecological niche, we studied the germination ecology of the mountain spring specialist, C. somedanum, a perennial species restricted to an unusual habitat for this genus. We conducted laboratory experiments with fresh seeds collected from two populations for three consecutive years, to investigate: (1) the effect of temperature and light ongermination; (2) the existence of seed dormancy; and (3) inter-population and inter-annual variation in germinability. Germination occurred only in the light and at relatively low temperatures (15?228C) with no differences between constant and alternating regimes, and a significant decrease at high temperatures (258C and 308C). We found non-deep simple morphophysiological dormancy and variation in seed germinability depending on the year of seed collection. C. somedanum diverged from the common germination characteristics of the genus in: (1) its germination at lower temperatures, which contrasts with what is generally expected in wetland species but could be adaptive in the spring habitat; and (2) its morphophysiological dormancy, which we report here for the first time in the genus and which could be an adaptation to its mountain habitat
The immunotherapy potential of agonistic anti-CD137 (4-1BB) monoclonal antibodies for malignancies and chronic viral diseases
Pharmacological intervention on the immune system to
achieve more intense lymphocyte responses has potential application
in tumour immunology and in the treatment of chronic
viral diseases. Immunostimulating monoclonal antibodies are
defined as a new family of drugs that augment cellular immune
responses. They interact as artificial ligands with functional proteins
of the immune system, either activating or inhibiting their
functions. There are humanized monoclonal antibodies directed
to the inhibitory receptor CD152 (CTLA-4) that are being tested
in clinical trials with evidence of antitumoural activity. As a
drawback, anti-CTLA-4 monoclonal antibodies induce severe
autoimmunity reactions in a fraction of the patients. Anti-CD137
monoclonal antibodies have the ability to induce potent
immune responses mainly mediated by cytotoxic lymphocytes
with the result of frequent complete tumour eradications in
mice. Comparative studies in experimental models indicate that
the antitumour activity of anti-CD137 monoclonal antibodies is
superior to that of anti-CD152. CD137 (4-1BB) is a leukocyte differentiation
antigen selectively expressed on the surface of activated
T and NK lymphocytes, as well as on dendritic cells. Monoclonal
antibodies acting as artificial stimulatory ligands of this
receptor (anti-CD137 agonist antibodies) enhance cellular antitumoural
and antiviral immunity in a variety of mouse models.
Paradoxically, anti-CD137 monoclonal antibodies are therapeutic
or preventive in the course of model autoimmune diseases in
mice. In light of these experimental results, a number of
research groups have humanized antibodies against human
CD137 and early clinical trials are about to start
Dendritic cells delivered inside human carcinomas are sequestered by interleukin-8
In the course of a clinical trial consisting of intratumoral injections of dendritic cells (DCs) transfected to produce interleukin-12, the use of (111)In-labeled tracing doses of DCs showed that most DCs remained inside tumor tissue, instead of migrating out. In search for factors that could explain this retention, it was found that tumors from patients suffering hepatocellular carcinoma, colorectal or pancreatic cancer were producing IL-8 and that this chemokine attracted monocyte-derived dendritic cells that uniformly express both IL-8 receptors CXCR1 and CXCR2. Accordingly, neutralizing antihuman IL-8 monoclonal antibodies blocked the chemotactic attraction of DCs by recombinant IL-8, as well as by the serum of the patients or culture supernatants of human colorectal carcinomas. In addition, tissue culture supernatants of colon carcinoma cells inhibited DC migration induced by MIP-3beta in an IL-8-dependent fashion. IL-8 production in malignant tissue and the responsiveness of DCs to IL-8 are a likely explanation of the clinical images, which suggest retention of DCs inside human malignant lesions. Impairment of DC migration toward lymphoid tissue could be involved in cancer immune evasion
Recombinant adenoviral vectors turn on the type I interferon system without inhibition of transgene expression and viral replication
Recombinant adenovirus administration gives rise to transgene-independent effects caused by the ability of the vector to activate innate immunity mechanisms. We show that recombinant adenoviruses encoding reporter genes trigger IFN-alpha and IFN-beta transcription from both plasmacytoid and myeloid mouse dendritic cells. Interestingly, IFN-beta and IFN-alpha5 are the predominant transcribed type I IFN genes both in vitro and in vivo. In human peripheral blood leukocytes type I IFNs are induced by adenoviral vectors, with a preponderance of IFN-beta together with IFN-alpha1 and IFN-alpha5 subtypes. Accordingly, functional type I IFN is readily detected in serum samples from human cancer patients who have been treated intratumorally with a recombinant adenovirus encoding thymidine kinase. Despite inducing functional IFN-alpha release in both mice and humans, gene transfer by recombinant adenoviruses is not interfered with by type I IFNs either in vitro or in vivo. Moreover, IFN-alpha does not impair replication of wild-type adenovirus. As a consequence, cancer gene therapy strategies with defective or replicative-competent adenoviruses are not expected to be hampered by the effect of the type I IFNs induced by the vector itself. However, type I IFN might modulate antitumor and antiadenoviral immune responses and thus influence the outcome of gene immunotherapy
What Darwin did not see : Pleistocene fossil assemblages on a highenergy coast at Ponta das Bicudas, Santiago, Cape Verde Islands
Two distinct Pleistocene assemblages from SE Santiago
Island are comparable to modern analogues elsewhere in
the Cape Verde Islands. A low-diversity Siderastrea radians
assemblage lived atop basalt knobs surrounded by sand on a
slope below a cliff. A Millepora alcicornis–Megabalanus
azoricus assemblage occupied the cliff. The latter was a
typical rocky-shore assemblage from a high-energy setting
belowthe tidal zone.Bioerosion structures in basalt produced
by Circolites kotoncensis and Gastrochaenolites isp. also
occur there. Despite extensive studies on local limestone
deposits in 1832 and 1836, lack of exposure prevented
Darwin from seeing these fossils.Funding for fieldwork on Santiago Island in June 2011 was provided under grant CGL2010-15372-BTE from the Spanish Ministry of Science and Innovation to project leader Eduardo Mayoral (University of Huelva). Financial support to A. Santos came from the Spanish Ministry of Science and Technology (Juan de la Cierva subprogram, Ref: JCI-2008-2431). Additional support by the Junta de Andalucia (Spanish government) to the Research Group RNM276 is also acknowledged. Partial funding to J. Ledesma-Vazquez on this project came from the Programma Integral de Fortalecimiento Institucional 2010. We thank Christopher K. Pham, Department of Oceanography and Fisheries, University of the Azores, Portugal, for help with identification of the fossil barnacles and Ricardo Ramalho, Institut fur Geophysik, Westphalishe-Wilhelms Universitat, Germany, for discussions about bioerosion by sea urchins on basalt surfaces
Checklist of the vascular plants of the Cantabrian Mountains
We present the first standardized list of the vascular flora of the Cantabrian Mountains, a transitional zone between the Eurosiberian and Mediterranean biogeographic regions in northwestern Spain. The study area comprises 15000 km2 divided in UTM grid cells of 10 km x 10 km, for which we revised occurrence data reported in the Spanish Plant Information System (Anthos) and the online database of Iberian and Macaronesian Vegetation (SIVIM). We used a semi-automatic procedure to standardize taxonomic concepts into a single list of names, which was further updated by expert-based revision with the support of national and regional literature. In the current version, the checklist of the Cantabrian Mountains contains 2338 native species and subspecies, from which 56 are endemic to the study area. The nomenclature of the checklist follows Euro+Med in 97% of taxa, including annotations when other criteria has been used and for taxa with uncertain status. We also provide a list of 492 non-native taxa that were erroneously reported in the study area, a list of local apomictic taxa, a phylogenetic tree linked to The Plant List, a standardized calculation of Ellenberg Ecological Indicator Values for 80% of the flora, and information about life forms, IUCN threat categories and legal protection status. Our review demonstrates how the Cantabrian mountains represent a key floristic region in southern Europe and a relevant phytogeographical hub in south-western Europe. The checklist and all related information are freely accessible in a digital repository for further uses in basic and applied researchThis research was supported by the Jardín Botánico Atlántico de Gijón (SV-20-GIJON-JBA) and SEEDALP project (Spanish Reearch Agency; PID2019-108636GA/AEI/10.13039/501100011033)Peer reviewe
A randomized phase II clinical trial of dendritic cell vaccination following complete resection of colon cancer liver metastasis
Surgically resectable synchronic and metachronic liver metastases of colon cancer have high risk of relapse in spite
of standard-of-care neoadjuvant and adjuvant chemotherapy regimens. Dendritic cell vaccines loaded with autologous
tumor lysates were tested for their potential to avoid or delay disease relapses (NCT01348256). Patients with surgically
amenable liver metastasis of colon adenocarcinoma (n = 19) were included and underwent neoadjuvant chemotherapy,
surgery and adjuvant chemotherapy. Fifteen patients with disease-free resection margins were randomized 1:1 to receive
two courses of four daily doses of dendritic cell intradermal vaccinations versus observation. The trial had been originally
designed to include 56 patients but was curtailed due to budgetary restrictions. Follow-up of the patients indicates a
clear tendency to fewer and later relapses in the vaccine arm (median disease free survival –DFS-) 25.26 months, 95% CI 8.
74-n.r) versus observation arm (median DFS 9.53 months, 95% CI 5.32–18.88)
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
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