10 research outputs found

    Integrated monitoring of mola mola behaviour in space and time

    Get PDF
    Over the last decade, ocean sunfish movements have been monitored worldwide using various satellite tracking methods. This study reports the near-real time monitoring of finescale (< 10 m) behaviour of sunfish. The study was conducted in southern Portugal in May 2014 and involved satellite tags and underwater and surface robotic vehicles to measure both the movements and the contextual environment of the fish. A total of four individuals were tracked using custom-made GPS satellite tags providing geolocation estimates of fine-scale resolution. These accurate positions further informed sunfish areas of restricted search (ARS), which were directly correlated to steep thermal frontal zones. Simultaneously, and for two different occasions, an Autonomous Underwater Vehicle (AUV) videorecorded the path of the tracked fish and detected buoyant particles in the water column. Importantly, the densities of these particles were also directly correlated to steep thermal gradients. Thus, both sunfish foraging behaviour (ARS) and possibly prey densities, were found to be influenced by analogous environmental conditions. In addition, the dynamic structure of the water transited by the tracked individuals was described by a Lagrangian modelling approach. The model informed the distribution of zooplankton in the region, both horizontally and in the water column, and the resultant simulated densities positively correlated with sunfish ARS behaviour estimator (r(s) = 0.184, p < 0.001). The model also revealed that tracked fish opportunistically displace with respect to subsurface current flow. Thus, we show how physical forcing and current structure provide a rationale for a predator's finescale behaviour observed over a two weeks in May 2014

    Stress granules, RNA-binding proteins and polyglutamine diseases: too much aggregation?

    Get PDF
    Stress granules (SGs) are membraneless cell compartments formed in response to different stress stimuli, wherein translation factors, mRNAs, RNA-binding proteins (RBPs) and other proteins coalesce together. SGs assembly is crucial for cell survival, since SGs are implicated in the regulation of translation, mRNA storage and stabilization and cell signalling, during stress. One defining feature of SGs is their dynamism, as they are quickly assembled upon stress and then rapidly dispersed after the stress source is no longer present. Recently, SGs dynamics, their components and their functions have begun to be studied in the context of human diseases. Interestingly, the regulated protein self-assembly that mediates SG formation contrasts with the pathological protein aggregation that is a feature of several neurodegenerative diseases. In particular, aberrant protein coalescence is a key feature of polyglutamine (PolyQ) diseases, a group of nine disorders that are caused by an abnormal expansion of PolyQ tract-bearing proteins, which increases the propensity of those proteins to aggregate. Available data concerning the abnormal properties of the mutant PolyQ disease-causing proteins and their involvement in stress response dysregulation strongly suggests an important role for SGs in the pathogenesis of PolyQ disorders. This review aims at discussing the evidence supporting the existence of a link between SGs functionality and PolyQ disorders, by focusing on the biology of SGs and on the way it can be altered in a PolyQ disease context.ALG-01-0145-FEDER-29480, SFRH/BD/133192/2017, SFRH/BD/133192/2017, SFRH/BD/148533/2019info:eu-repo/semantics/publishedVersio

    Designing Pt nanoparticles supported on CeO2-Al2O3 Synthesis, characterization and catalytic properties in the steam reforming and partial oxidation of methane

    No full text
    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Platinum nanoparticles (Pt-NPs) of about 3 nm were synthesized by colloidal methods and encapsulated in mesoporous Al2O3 and CeO2-Al2O3 prepared by sol-gel method A new strategy to synthesize Pt clusters of uniform size supported on mixed oxides was achieved and the catalysts were characterized by Fourier transform Infrared spectroscopy of adsorbed CO transmission electron microscopy and X-ray absorption fine structure spectroscopy and tested in steam reforming of methane (SRM) and partial oxidation of methane (POM) Pt-NPs were well dispersed on the supports and there was no significant modification of their size during calcination and under POM conditions In the SRM the CH4 turnover rate on the Pt-NPs/CeO2-Al2O3 catalyst was twice higher than the one on the Pt-NPs/Al2O3 catalyst despite their similar Pt-NP sizes The use of colloidal Pt-NPs to produce nanocatalysts with similar particle size clearly pointed out the important role of the CeO2 in promoting the catalytic activity (C) 2010 Elsevier Inc All rights reserved2762351359Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Characterization of Oblique Dual Frame Pairs

    Get PDF
    <p/> <p>Given a frame for a subspace <inline-formula><graphic file="1687-6180-2006-092674-i1.gif"/></inline-formula> of a Hilbert space <inline-formula><graphic file="1687-6180-2006-092674-i2.gif"/></inline-formula>, we consider all possible families of oblique dual frame vectors on an appropriately chosen subspace <inline-formula><graphic file="1687-6180-2006-092674-i3.gif"/></inline-formula>. In place of the standard description, which involves computing the pseudoinverse of the frame operator, we develop an alternative characterization which in some cases can be computationally more efficient. We first treat the case of a general frame on an arbitrary Hilbert space, and then specialize the results to shift-invariant frames with multiple generators. In particular, we present explicit versions of our general conditions for the case of shift-invariant spaces with a single generator. The theory is also adapted to the standard frame setting in which the original and dual frames are defined on the same space.</p

    Evaluation of Water Variables in No-Take Zone of Ustica Marine Protected Area (Southern Tyrrhenian Sea)

    No full text
    ABSTRACT In this research, the seasonal fluctuations of the main water variables in the no-take area (A zone) of the Ustica MPA were investigated. This study aims to monitor the water quality of the Ustica MPA, to analyze all the hydrological parameters useful to the physical-chemical characterization of water and to use TRIX index to characterize the trophic level of the coastal marine area. The final results shown that Ustica is an area of relevant environmental and ecological value and is a good example of a Marine Protected Area, which is not excessively affected by the human presence even during the touristic season. This study represents the first records based on well-organized protocol in order to assess water column characteristics of the studied area. This paper could be used as a reference document for future studies regarding the same or similar areas
    corecore