The Dusty Tori of Nearby QSOs as Constrained by High-Resolution Mid-IR Observations

We present mid-infrared (MIR; 7.5–13.5 μm) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4-m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs). We find that for the majority of QSOs the MIR emission is unresolved at angular scales ∼0.3 arcsec, corresponding to physical scales ≲ 600 pc. We find that the higher-spatial resolution CC spectra have similar shapes to those obtained with Spitzer/IRS, and hence we can assume that the spectra are not heavily contaminated by extended emission in the host galaxy. We thus take advantage of the higher signal-to-noise ratio Spitzer/IRS spectra, as a fair representation of the nuclear emission, to decompose it into a combination of active galactic nuclei (AGN), polycyclic aromatic hydrocarbon (PAH) and stellar components. In most cases, the AGN is the dominant component, with a median contribution of 85 per cent of the continuum light at MIR (5–15 μm) within the IRS slit. This IR AGN emission is well reproduced by clumpy torus models. We find evidence for significant differences in the parameters that describe the dusty tori of QSOs when compared with the same parameters of Seyfert 1 and 2 nuclei. In particular, we find a lower number of clouds (N0 ≲ 12), steeper radial distribution of clouds (q ∼ 1.5–3.0) and clouds that are less optically thick (τV ≲ 100) than in Seyfert 1, which could be attributed to dusty structures that have been partially evaporated and piled up by the higher radiation field in QSOs. We find that the combination of the angular width σtorus, viewing angle i, and number of clouds along the equatorial line, N0, produces large escape probabilities (Pesc \u3e 2 per cent) and low geometrical covering factors (f2 ≲ 0.6), as expected for AGN with broad lines in their optical spectra

Lateralization in the escape behaviour of the common wall lizard (_Podarcis muralis_)

Lateralization in ectotherms is now as well studied as in endotherms. Bias in eye use seems widespread, particularly in several ectotherms, most of them having lateral eyes. Several studies evidenced that the right eye/left hemisphere is involved in predatory behaviour and food searching while the left eye/right hemisphere seems to control predator monitoring, making lateralized individuals able to carry out both tasks simultaneously. Starting from previous observations that demonstrated a right-eye/left-hemisphere preference for observing a prey in common wall lizards, Podarcis muralis, we investigated whether a visual lateralization in antipredatory behaviour is present too. In a first experiment, we induced lizards in a terrarium to escape from a simulated predator attacking from behind, recording the direction of the escape path in relation to the starting point. We found that the preferred escape direction of most lateralized individuals was to the right and there was also a strong rightward preference in escape direction as a whole. In a second experiment the lizards, again stimulated from behind, had to choose to run down either the right or the left arm of a semi-circular tunnel ("ram-horn" maze). The rightward preference in escape behaviour was confirmed in this experiment too. We conclude that the constant rightward escape could be due to a left-eye early perception of the threatening cue and to the possibility it gives of better monitoring of most of the terrarium surface. Moreover, we found a left bias in turning the head for monitoring the predatory stimulus during escape, supporting the hypothesis that such a preference is likely due to visual lateralization rather than to motor lateralization

Lateralization when monitoring predators in the wild: a left eye control in the common wall lizard (_Podarcis muralis_)

Lateralization is the function specialization between left and right brain hemispheres. It is now ascertained in ectotherms too, where bias in eye use for different tasks, i.e., visual lateralization, is widespread. The lateral eye position on the head of ectotherm animals, in fact, allows them to observe left/right stimuli independently and allows lateralized individuals to carry out left and right perceived tasks at the same time. A recent study conducted on common wall lizards, Podarcis muralis, showed that lizards predominantly monitor a predator with the left eye while escaping. However, this work was conducted in a controlled laboratory setting owing to the difficulty of carrying out lateralization experiments under natural conditions. Nevertheless, field studies could provide important information to support what was previously found in the laboratory and demonstrate that these traits occur in nature. In this study, we conducted a field study on the antipredatory behavior of P. muralis lizards. We simulated predatory attacks on lizards in their natural environment. We found no lateralization in the measure of eye used by the lizard to monitor the predator before escaping from it, but the eye used was probably determined by the relative position of the lizard and the predator just before the attack. This first eye used did not affect escape decisions; lizards chose to escape toward the nearest refuge irrespective of whether it was located to the lizard’s left or right side. However, once they had escaped to a refuge, lizards had a left eye–mediated bias to monitor the predator when first emerging from the refuge, and this bias was likely independent of other environmental variables. Hence, these field findings support a left eye–mediated observation of the predator in P. muralis lizards, which confirms previous findings in this and other species

Is the _Podarcis muralis_ lizard left-eye lateralized when exploring a new environment?

Articolo segnalato da “Faculty of 1000” (www.facultyof1000.com), 07 ottobre 2010

Diseño e implementación de una aplicación web para la optimización de los procesos administrativos del msia y msig

El presente articulo es para dar a conocer una aplicacion web llamada SAP (Sistema para la Administracion de Unidades de Postgrado), la cual permitirá la administracion de dicha unidad académica. Es una herramienta cuyo proposito general es el de brindar una solucion a la problematica que se presenta al momento de administrar esta unidad académica, los cuales es su mayoria son la excesiva informacion que se encuentra almacenada en carpetas sin tener un respaldo en un repositorio de una base de dato, lo cual se convierte en un gran problema si esta informacion llegase a perderse de las carpetas

Effectiveness of chemotherapy in advanced differentiated thyroid cancer: a systematic review.

In differentiated thyroid carcinoma refractory to radioactive iodine (CDT-RTI), chemotherapy has been considered for decades to be the only systemic therapy with palliative purpose. Phase II studies assessing the efficacy of different chemotherapy outlines have been published. Nevertheless, phase III studies in these tumours have not been performed. Our objective is to evaluate the effectiveness of chemotherapy in patients with CDT-RTI by a systematic review of published studies. Systematic research of the literature in Medline and Embase databases (among others) was carried out. The full texts of selected references were analysed by two independent reviewers and then assessed for risk of bias in each study. We also extracted data using specifically designed questionnaires. Later, a qualitative synthesis of results was performed and pooled data were calculated. We found that 16 studies with 473 patients published in the last 40 years were included out of 509 identified references in databases. Thirteen studies (176 patients) included data on response to treatment and histology. Four studies included 70 patients only with well-differentiated non-medullary tumours. Response rate (RR) was 22.1% (0-57%) for 13 studies, 25% for the 176 patients and 27.1% for the 70 patients, with 2.5, 3.4 and 2.8% complete responses respectively. Survival times could not be assessed or pooled due to the lack of data and heterogeneity of the studies, and was determined to have a high risk of bias. Although it has not been possible to find solid evidence about the efficacy of chemotherapy, the results shown indicate that it may have some effectiveness, although this should be proven with well-designed studies using modern drugs

Folic Acid Protects Against Glutamate-Induced Excitotoxicity in Hippocampal Slices Through a Mechanism that Implicates Inhibition of GSK-3β and iNOS

Folic acid (folate) is a vitamin of the B-complex group crucial for neurological function. Considering that excitotoxicity and cell death induced by glutamate are involved in many disorders, the potential protective effect of folic acid on glutamate-induced cell damage in rat hippocampal slices and the possible intracellular signaling pathway involved in such effect were investigated. The treatment of hippocampal slices with folic acid (100 μM) significantly abrogated glutamate (1 mM)-induced reduction of cell viability measured by MTT reduction assay and inhibited glutamate-induced D-[3H]-aspartate release. To investigate the putative intracellular signaling pathways implicated in the protective effect of folic acid, we used a PI3K inhibitor, LY294002, which abolished the protective effects of folic acid against glutamate-induced cell damage and D-[3H] aspartate release. Moreover, hippocampal slices incubated with folic acid alone for 30 min presented increased phosphorylation of GSK-3β at Ser9, indicating an inhibition of the activity of this enzyme. Furthermore, folic acid in the presence of glutamate insult in hippocampal slices maintained for an additional period of 6 h in fresh culture medium without glutamate and/or folic acid induced phosphorylation of GSK-3β and β-catenin expression. In addition, glutamate-treated hippocampal slices showed increased iNOS expression that was reversed by folic acid. In conclusion, the results of this study show that the protective effect of folic acid against glutamate-induced excitotoxicity may involve the modulation of PI3K/GSK-3β/β-catenin pathway and iNOS inhibition.Conselho de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)IBNNet/CNPqNENASC projectSpanish Ministry of Science and InnovationMinistry of EducationDepto. de Bioquímica y Biología MolecularFac. de FarmaciaTRUEpu

The dusty tori of nearby QSOs as constrained by high-resolution mid-IR observations

We present mid-infrared (MIR; 7.5-13.5 μm) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4-m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs).We find that for the majority of QSOs the MIR emission is unresolved at angular scales~0.3 arcsec, corresponding to physical scales ≲600 pc. We find that the higher-spatial resolution CC spectra have similar shapes to those obtained with Spitzer/IRS, and hence we can assume that the spectra are not heavily contaminated by extended emission in the host galaxy. We thus take advantage of the higher signal-to-noise ratio Spitzer/IRS spectra, as a fair representation of the nuclear emission, to decompose it into a combination of active galactic nuclei (AGN), polycyclic aromatic hydrocarbon (PAH) and stellar components. In most cases, the AGN is the dominant component, with a median contribution of 85 per cent of the continuum light at MIR (5-15 μm) within the IRS slit. This IR AGN emission is well reproduced by CLUMPY torus models. We find evidence for significant differen ces in the parameters that describe the dusty tori of QSOs when compared with the same parameters of Seyfert 1 and 2 nuclei. In particular, we find a lower number of clouds (N0 ≲ 12), steeper radial distribution of clouds (q ~ 1.5-3.0) and clouds that are less optically thick (τ V ≲ 100) than in Seyfert 1, which could be attributed to dusty structures that have been partially evaporated and piled up by the higher radiation field in QSOs. We find that the combination of the angular width σ torus , viewing angle i, and number of clouds along the equatorial line, N0, produces large escape probabilities (P esc > 2 per cent) and low geometrical covering factors (f 2 ≲ 0.6), as expected for AGN with broad lines in their optical spectra

Synthesis of (+)-Coniceine via Reductive Photocyclization of Dienamides: An Entry to Indolizidines

This paper describes the establishment of a new synthetic route to the hydrobromide salt of (+)-coniceine 1 with high enantiopurity in five steps and 8% overall yield. The key step is the reductive photocyclization of an acyclic chiral dienamide, for which a convenient one-pot synthesis is described