556 research outputs found
Dinosaurs and other vertebrates from the Papo-Seco Formation (Lower Cretaceous) of southern Portugal
New vertebrate remains reported from the Papo-Seco Formation (Lower Barremian, Lower Cretaceous) of Areias do Mastro, in Cabo Espichel, SW Portugal, south of Lisbon. The marine, lagoonal, and estuarine limestones, marls, sands and gravels have yielded remains of dinosaurs and other reptiles since the 19th century. Recent paleontological prospecting produced several vertebrate remains, including turtle shell fragments, crocodilian teeth, fish and pterosaurs. Research identified both bones and teeth of fish, crocodiles, dinosaurs Baryonyx and iguanodontian, as well as a ctenochasmatoid pterosaur, and a possible ornithocheirid pterosaur. These new disclosures are an important contribution to the knowledge of vertebrate diversity from the Portuguese Cretaceous. Faunal species combination proven to be similar to other faunal associations of Barremian formations in the Iberian Peninsula.Se presentan nuevos restos fósiles de vertebrados de la formación Papo-Seco (Barremiense inferior, Cretácico Inferior), en el yacimiento de Areias do Mastro, SW de Portugal, al sur de Lisboa. En las margas, arenas, areniscas y calizas de origen marino y estuarino de esta formación localizada en el Cabo Espichel, y ya desde el siglo XIX, se han encontrado restos de dinosaurios y otros reptiles. Recientemente, nuestra prospección sacó a la luz varios restos fósiles de vertebrados, entre los que se incluyen fragmentos de caparazón de tortuga, dientes de cocodrilo, de peces actinopterigios y de pterosaurio (ctenocasmatoideo y posiblemente ornitoqueiroideo), así como algunos huesos y dientes de dinosaurios. Hemos identificado restos de Baryonyx y de ornitópodos iguanodontios. Su descubrimiento representa una importante contribución al conocimiento de la diversidad de vertebrados existentes en el Cretácico portugués. La combinación de las especies muestra ser similar a otras asociaciones de la fauna de las formaciones Barremienses en la Península Ibérica
Physical Conditions in Circumstellar Gas surrounding SN 1987A 12 Years After Outburst
Two-dimensional spectra of Supernova 1987A were obtained on 1998 November
14-15 (4282 days after outburst) with the Space Telescope Imaging Spectrograph
(STIS) on board the Hubble Space Telescope (HST). The slit sampled portions of
the inner circumstellar ring at the east and west ansae as well as small
sections of both the northern and southern outer rings. The temperature and
density at these locations are estimated by nebular analysis of [N II], [O
III], and [S II] emission line ratios, and with time-dependent
photoionization/recombination models. The results from these two methods are
mutually consistent. The electron density in the inner ring is ~ 4000 cm-3 for
S II, with progressively lower densities for N II and O III. The electron
temperatures determined from [N II] and [O III] line ratios are ~11,000 K and
\~22,000 K, respectively. These results are consistent with evolutionary trends
in the circumstellar gas from similar measurements at earlier epochs. We find
that emission lines from the outer rings come from gas of lower density (n_e
\la 2000 cm-3) than that which emits the same line in the inner ring. The N/O
ratio appears to be the same in all three rings. Our results also suggest that
the CNO abundances in the northern outer ring are the same as in the inner
ring, contrary to earlier results of Panagia et al. (1996). Physical conditions
in the southern outer ring are less certain because of poorer signal-to-noise
data. The STIS spectra also reveal a weak Ha emission redshifted by ~100 km s-1
at p.a. 103\arcdeg that coincides with the recently discovered new regions that
are brightening (Lawrence et al. 2000). This indicates that the shock
interaction in the SE section of the inner ring commenced over a year before it
became apparent in HST images.Comment: 25 pages, 6 figures, to appear in December 1, 2000 Astrophysical
Journa
Stiff‐Stilbene Ligands Target G‐Quadruplex DNA and Exhibit Selective Anticancer and Antiparasitic Activity
G-quadruplex nucleic acid structures have long been studied as anticancer targets whilst their potential in antiparasitic therapy has only recently been recognized and barely explored. Herein, we report the synthesis, biophysical characterization, and in vitro screening of a series of stiff-stilbene G4 binding ligands featuring different electronics, side-chain chemistries, and molecular geometries. The ligands display selectivity for G4 DNA over duplex DNA and exhibit nanomolar toxicity against Trypasanoma brucei and HeLa cancer cells whilst remaining up to two orders of magnitude less toxic to non-tumoral mammalian cell line MRC-5. Our study demonstrates that stiff-stilbenes show exciting potential as the basis of selective anticancer and antiparasitic therapies. To achieve the most efficient G4 recognition the scaffold must possess the optimal electronics, substitution pattern and correct molecular configuration.M.P.O. thanks the Bristol Chemical Synthesis Centre for Doctoral Training, funded by EPSRC (EP/L015366/1) and the University
of Bristol for a PhD studentship. J.C.M./P.P. thank Spanish Ministerio de Ciencia Innovación y Universidades (Grants CTQ2015-
64275-P and RTI2018-099036-B-I00). M.C.G. thanks the European Research Council (ERC-COG: 648239
Geoarchaeology of Pleistocene open-air sites in the Vila Nova da Barquinha-Santa Cita area (Lower Tejo River basin, central Portugal)
This paper aims to provide insight into human occupation and landscape change during the Pleistocene
in a central area of the Lower Tejo basin (Portugal). Detailed geomorphological mapping, coupled with
lithostratigraphy, sedimentology and luminescence dating, supports the identification of a complete
terrace staircase sequence. It consists of six gravely terraces located below the culminant (Pliocene)
basin unit. A chronological framework for the sedimentary sequences and associated human industries
is proposed and correlated with marine oxygen isotope stages (MIS): T1 terrace, not dated; T2, not dated;
T3, >300 ka; T4, 300–160 ka (MIS8, MIS7 and MIS6); T5, 136–75 ka (MIS5); T6, 62–30 ka (MIS3);
colluviumand aeolian sands, 30–14 ka (MIS2); valley fill deposits, 14 ka to present (MIS1). The oldest
artefacts were found at the base of the T4 terrace, with the local stratigraphic level dated to 175 6 ka
(Middle Pleistocene). The lithic assemblages collected from distinct stratigraphic levels (T4, T5 top, T6
terraces and colluvium) are characterized by the predominance of opportunistic technological choices, a
feature that can be attributed partly to the preferential exploitation of the available raw material, dominated
by local-sourced quartzites and quartz pebbles. The adaptation to local raw material (texture and volume),
together with subsistence patterns and behaviours, could explain the rarity of Acheulian types (handaxes and
cleavers) and picks in the T4 terraces of the Tejo tributaries; this is in contrast to the same terrace of the Tejo
valley, in which these types are found. Interpretation of the environmental conditions (controlled by climate
and glacio-eustatic sea-level changes) affecting the hunter-gatherer human groups is also presente
Geochemistry of phosphatic nodules as a tool for understanding depositional and taphonomical settings in a paleolithic cave site (San teodoro, Sicily)
Interpreting depositional settings of cave sites is generally problematic, especially in absence of paleontological/archaeological evidence. This is the case of some deposits at San Teodoro Cave (Sicily), a key site for the Mediterranean Paleolithic. In a stratigraphic level interrupted by a carbonatic concretion, phosphatic nodules are present only in the part enclosed between the concretion and the cave wall. The discovery of these nodules combined with the punctual lack of fossils had initially suggested an erosion phenomenon and subsequent formation of nodules at a vadose level. Here we show the usefulness of an integrated, geochemical-paleoecological approach in defining stratigraphy and paleoenvironmental reconstructions. XRD, ICP-OES, ATR-FTIR and EDS analyses allowed the formulation of a new hypothesis regarding the origin of the nodules, the depositional dynamics, and the role played by the guano produced by an extensive colony of bats. The role of barium and rubidium in detecting taphonomical processes has been highlighted
Raw Sewage Harbors Diverse Viral Populations
At this time, about 3,000 different viruses are recognized, but metagenomic studies suggest that these viruses are a small fraction of the viruses that exist in nature. We have explored viral diversity by deep sequencing nucleic acids obtained from virion populations enriched from raw sewage. We identified 234 known viruses, including 17 that infect humans. Plant, insect, and algal viruses as well as bacteriophages were also present. These viruses represented 26 taxonomic families and included viruses with single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), positive-sense ssRNA [ssRNA(+)], and dsRNA genomes. Novel viruses that could be placed in specific taxa represented 51 different families, making untreated wastewater the most diverse viral metagenome (genetic material recovered directly from environmental samples) examined thus far. However, the vast majority of sequence reads bore little or no sequence relation to known viruses and thus could not be placed into specific taxa. These results show that the vast majority of the viruses on Earth have not yet been characterized. Untreated wastewater provides a rich matrix for identifying novel viruses and for studying virus diversity
Estimation of faecal excretion in alpacas (Vicugna pacos) in confinement conditions using titanium dioxide
El objetivo del estudio fue estimar la producción de heces en alpacas con el uso del dióxido de titanio (TiO2). Se usó un diseño cuadrado latino 4x4, con cuatro animales, cuatro tratamientos y cuatro periodos. Cada periodo de 14 días de experimentación y siete de descanso. Los tratamientos fueron: T2.5(1), 2.5 g de TiO2/animal/día; T1.25(2), 2.5 g de TiO2/animal/día repartido en dos dosis (07:00, 16:00); T5(1), 5 g de TiO2/animal/día; T2.5(2), 5 g de TiO2/animal/día repartido en dos dosis (07:00, 16:00). Los porcentajes de la recuperación de TiO2 fueron de 90, 82, 78 y 52% para T2.5(1), T1.25(2), T5(1) y T2.5(2), respectivamente, siendo T2.5(2) diferente a los otros tratamientos (p=0.00013). Los parámetros del patrón de excreción del TiO2 fueron: intercepto de la curva de la excreción de TiO2 en el tiempo cero (a), máxima excreción del TiO2 en tiempo (b), la tasa constante de excreción de b (c), tiempo necesario de excreción de TiO2 para que haya excretado la mitad de la concentración inicial (T1/2) y tiempo para alcanzar el equilibrio de excreción del marcador (T(a+b)). No hubo diferencia entre tratamientos para los valores de a, c, T medio y T, pero hubo diferencia significativa del valor de b entre la administración del marcador de 2.5 vs. 5 g (p<0.0001). Los promedios de producción de heces estimada con TiO2 vs. producción de heces observada directamente fue diferente en T1.25(2), T5(1) y T2.5(2) (p<0.05), pero no en T2.5(1). En conclusión, el tiempo en el que se alcanza el equilibrio de excreción del TiO2 es de aproximadamente ocho días y la dosis de 2.5 g de TiO2 una vez al día estima con mayor precisión la producción fecal en alpacas.The aim of this study was to estimate the production of faeces in alpacas with the use of titanium dioxide (TiO2). A square 4x4 Latin design was used, with four animals, four treatments and four periods. Each period last for 14 days of evaluation and seven days of rest. The treatments were: T2.5 (1), 2.5 g of TiO2/animal/day; T1.25(2), 2.5 g of TiO2/animal/day divided into two doses (07:00, 16:00); T5(1), 5 g of TiO2/animal/day; T2.5(2), 5 g of TiO2/animal/day divided into two doses (07:00, 16:00). The percentages of the recovery of TiO2 were 90, 82, 78 and 52% for T2.5(1), T1.25(2), T5(1) and T2.5(2), respectively, being T2.5(2) different from the other treatments (p=0.00013). The parameters of the TiO2 excretion pattern were: intercept of the curve of TiO2 excretion at time zero (a), maximum excretion of TiO2 at time (b), constant rate of excretion of b (c), time needed of excretion of TiO2 so that it has excreted half of the initial concentration (T1/2), and time to reach the balance of excretion of the marker (T (a+b)). There was no difference between treatments for the values of a, c, mean T and T, but there was a significant difference in the value of b between the administration of the marker of 2.5 vs 5 g (p<0.0001). The averages of faecal production estimated with TiO2 vs. faecal production observed directly was different in T1.25(2), T5(1) and T2.5(2) (p<0.05), but not in T2.5(1). In conclusion, the time in which the excretion equilibrium of TiO2 is reached is approximately eight days and the dose of 2.5 g of TiO2 once a day more accurately estimates faecal production in alpacas
Bullous pemphigoid and comorbidities: a case-control study in Portuguese patients
BACKGROUND:
Although rare, bullous pemphigoid (BP) is the most common autoimmune blistering disease. Recent studies have shown that patients with bullous pemphigoid are more likely to have neurological and psychiatric diseases, particularly prior to the diagnosis of bullous pemphigoid.
OBJECTIVE:
The aims were: (i) to evaluate the demographic and clinical features of bullous pemphigoid from a database of patients at a Portuguese university hospital and (ii) to compare the prevalence of comorbid conditions before the diagnosis of bullous pemphigoid with a control group.
METHODS:
Seventy-seven patients with bullous pemphigoid were enrolled in the study. They were compared with 176 age- and gender-matched controls, which also had the same inpatient to outpatient ratio, but no history of bullous or cutaneous malignant disease. Univariate and multivariate analyses were used to calculate odds ratios for specific comorbid diseases.
RESULTS:
At least one neurologic diagnosis was present in 55.8% of BP patients compared with 20.5% controls (p<0.001). Comparing cases to controls, stroke was seen in 35.1 vs. 6.8%, OR 8.10 (3.80-17.25); dementia in 37.7 vs. 11.9%, OR 5.25 (2.71-10.16); and Parkinson's disease in 5.2 vs. 1.1%, OR 4.91 (0.88-27.44). Using multivariate analysis, all diseases except Parkinson's retained their association with BP. Patients under systemic treatment were eight times more likely to have complications than those treated with topical steroids (p< 0.017).
CONCLUSIONS:
The results of this study substantiate the association between BP and neurological diseases. In addition, they highlight the potential complications associated with the treatment of BP
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