264 research outputs found
CleverRiver: an open source and free Google Colab toolkit for deep-learning river-flow models
In a period in which climate change is significantly varying rainfall regimes and their intensity all over the world, river-flow prediction is a major concern of geosciences. In recent years there has been an increase in the use of deep-learning models for river-flow prediction. However, in this field we can observe two main issues: i) many case studies use similar (or the same) strategies without sharing the codes, and ii) the application of these techniques requires good computer knowledge. This work proposes to employ a Google Colab notebook called CleverRiver, which allows the application of deep-learning for river-flow predictions. CleverRiver is a dynamic software that can be upgraded and modified not only by the authors but also by the users. The main advantages of CleverRiver are the following: the software is not limited by the client hardware, operating systems, etc.; the code is open-source; the toolkit is integrated with user-friendly interfaces; updated releases with new architectures, data management, and model parameters will be progressively uploaded. The software consists of three sections: the first one enables to train the models by means of some architectures, parameters, and data; the second section allows to create predictions by using the trained models; the third section allows to send feedback and to share experiences with the authors, providing a flux of precious information able to improve scientific research
Small sinkhole-like features in alluvial plains: the example of Paganico (Lucca Plain, Italy)
Paganico is a little village located in the southeastern portion of the
Lucca Plain (northwestern Tuscany, Italy). Since the seventies, a few square
kilometers' area around Paganico has been involved in the opening of small
cavities (sinkhole-like) on the land surface. At the beginning they were very
small and sporadic. Later on the phenomena were characterized by a
significant extension, increasing in frequency and size (up to 2 m in
diameter and depth), causing inconvenience to local people, agricultural
operations and occasionally a little damage (cracks to buildings, fencing walls
and outside floorings).
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The cavities prevalently occur at the end of the dry season, during or
immediately after the first intense rainy events, that is, between the end of
summer and early autumn. Even so, the predisposition and triggering causes at present are not
completely clarified. Therefore this study is aimed at
individuating the triggering and evolution mechanism of the Paganico
sinkhole-like features, particularly referring to the stratigraphic,
hydrogeological and geotechnical features of the involved materials.
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Another important issue made clear with this research is represented by the
overexploitation of the local aquifer, characterized by particular
hydro-structural conditions. In fact, the Paganico underground shows three
horizons with different lithologic, hydrogeological and geotechnical
properties: a superficial silty-sandy horizon (2–3 m thick), which is
particularly involved in collapses; an intermediate silty-clayey horizon
(2–4 m thick); and a lower and thick gravel-pebbly horizon, characterized by
important water resources and heavy pumping. Since the seventies, such water
pumping rose considerably due to the local demographic (well field),
industrial (paper manufacture) and agricultural development.
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From a hydrogeological point of view, this area is consequently characterized
by two water tables: a temporary one, housed in the superficial silty-sandy
horizon (perched aquifer), and a second one, confined, associated with the
lower gravel-pebbly horizon (aquifer). The perched aquifer and confined
aquifer are separated by an impermeable silty-clayey horizon. According to
the observations resulting from this study, the latter probably tends to
fracture by desiccation during the dry season, originating water exchange
between the two water tables during the first important autumnal rainfall,
depending on the pumping conditions, which lower the piezometric surface of
the confined aquifer. Cracking would also characterize the superficial
horizon. Thus, the water exchange would produce erosional phenomena in the
superficial material, with removal of the fine fraction and collapse. This
process could be at the origin of the cavities opening
Seasonal rainfall trends of a key Mediterranean area in relation to large-scale atmospheric circulation: How does current global change affect the rainfall regime?
Current global warming causes a change in atmospheric dynamics, with consequent variations in the rainfall regimes. Understanding the relationship between global climate patterns, global warming, and rainfall regimes is crucial for the creation of future scenarios and for the relative modification of water management. The aim of this study is to improve knowledge of the relationship between North Atlantic Oscillation (NAO), East Atlantic (EA), and Western Mediterranean Oscillation (WeMO) with the seasonal rainfalls in Tuscany, Italy. The study area occupies a strategic position since it lies in a transition zone between the wet area of northern Europe and the dry area of the northern coast of Africa. This research, based on a statistical correlation method and on linear models, is designed to understand the relationship between seasonal rainfalls and climate patterns. The results of this study demonstrate that the use of linear models can yield more information than traditional statistical corre-lations. The results show a decrease in rainfall in the warm period of the year, namely in the summer, when its expression is most visible. This phenomenon is ascribable to current global warming, which causes an increase in sea-surface temperatures. An increase in the Northern Atlantic Sea Surface Temperature and in the Mediterra-nean Sea Surface Temperature causes a reduction of the Iceland Low, with an extension of the Azores High. Moreover, an increase in the Genoa Gulf SST induces a weakening of the Genoa Gulf Low, one of the main cyclogenetic systems of the Mediterranean
Toxicity of thallium at low doses: A review
A mini review of the toxicity of Thallium (Tl) at low doses is herein presented. Thallium has severe toxicity. Although its acute biological effects have been widely investigated and are well known, its biological effects on human health and in cell cultures at low doses (<100 µg/L) due, for example, to Tl chronic exposure via consumption of contaminated water or foods, have often been overlooked or underestimated. Relatively few papers have been published on this topic and are herein reviewed to provide a focused scientific opinion in the light of current worldwide regulatory issues
Vaccination with an Inactivated Virulent Feline Immunodeficiency Virus Engineered to Express High Levels of Env
An inactivated virus vaccine was prepared from a pathogenic isolate of feline immunodeficiency virus containing a mutation that eliminated an endocytic sorting signal in the envelope glycoprotein, increasing its expression on virions. Cats immunized with inactivated preparations of this modified virus exhibited strong titers of antibody to Env by enzyme-linked immunosorbent assay. Evidence of protection following challenge demonstrated the potential of this approach to lentiviral vaccination
Estimation of the susceptibility of a road network to shallow landslides with the integration of the sediment connectivity
Abstract. Landslides cause severe damage to the road network of the hit zone, in terms of
both direct (partial or complete destruction of a road or blockages) and
indirect (traffic restriction or the cut-off of a certain area) costs. Thus, the
identification of the parts of the road network that are more susceptible to
landslides is fundamental to reduce the risk to the population potentially
exposed and the financial expense caused by the damage. For these reasons,
this paper aimed to develop and test a data-driven model for the
identification of road sectors that are susceptible to being hit by shallow
landslides triggered in slopes upstream from the infrastructure. This model was
based on the Generalized Additive Method, where the function relating
predictors and response variable is an empirically fitted smooth function
that allows fitting the data in the more likely functional form, considering
also non-linear relations. This work also analyzed the importance, on the
estimation of the susceptibility, of considering or not the sediment
connectivity, which influences the path and the travel distance of the
materials mobilized by a slope failure until hitting a potential barrier such as a road.
The study was carried out in a catchment of northeastern Oltrepò Pavese
(northern Italy), where several shallow landslides affected roads in the last
8 years. The most significant explanatory variables were selected by a random
partition of the available dataset in two parts (training and test subsets),
100 times according to a bootstrap procedure. These variables (selected
80 times by the bootstrap procedure) were used to build the final
susceptibility model, the accuracy of which was estimated through a 100-fold
repetition of the holdout method for regression, based on the training and test
sets created through the 100 bootstrap model selection. The presented
methodology allows the identification, in a robust and reliable way, of the
most susceptible road sectors that could be hit by sediments delivered by
landslides. The best predictive capability was obtained using a model in
which the index of connectivity was also calculated according to a linear
relationship, was considered. Most susceptible road traits resulted to be
located below steep slopes with a limited height (lower than 50 m), where
sediment connectivity is high. Different land use scenarios were considered in
order to estimate possible changes in road susceptibility. Land use classes
of the study area were characterized by similar connectivity features. As a
consequence, variations on the susceptibility of the road network according
to different scenarios of distribution of land cover were limited. The
results of this research demonstrate the ability of the developed methodology
in the assessment of susceptible roads. This could give the managers of
infrastructure information about the criticality of the different road traits,
thereby allowing attention and economic budgets to be shifted towards the
most critical assets, where structural and non-structural mitigation measures
could be implemented
Interaction of short modified peptides deriving from glycoprotein gp36 of feline immunodeficiency virus with phospholipid membranes
A tryptophan-rich octapeptide, C8 (Ac-Trp-Glu-Asp-Trp-Val-Gly-Trp-Ile-NH2), modelled on the membrane-proximal external region of the feline immunodeficiency virus (FIV) gp36 glycoprotein ectodomain, exhibits potent antiviral activity against FIV. A mechanism has been proposed by which the peptide, being positioned on the surface of the cell membrane, inhibits its fusion with the virus. In the present work, peptide–lipid interactions of C8 with dimyristoyl phosphatidylcholine liposomes are investigated using electron spin resonance spectroscopy of spin-labelled lipids. Three other peptides, obtained from modifications of C8, have also been investigated, in an attempt to clarify the essential molecular features of the interactions involving the tryptophan residues. The results show that C8 adsorbs strongly on the bilayer surface. Membrane binding requires not only the presence of the Trp residues in the sequence, but also their common orientation on one side of the peptide that is engendered by the WX2 WX2 W motif. Membrane interaction correlates closely with peptide antiviral activity, indicating that the membrane is essential in stabilizing the peptide conformation that will be able to inhibit viral infection
Selective expansion of viral variants following experimental transmission of a reconstituted feline immunodeficiency virus quasispecies
Following long-term infection with virus derived from the pathogenic GL8 molecular clone of feline immunodeficiency virus (FIV), a range of viral variants emerged with distinct modes of interaction with the viral receptors CD134 and CXCR4, and sensitivities to neutralizing antibodies. In order to assess whether this viral diversity would be maintained following subsequent transmission, a synthetic quasispecies was reconstituted comprising molecular clones bearing envs from six viral variants and its replicative capacity compared in vivo with a clonal preparation of the parent virus. Infection with either clonal (Group 1) or diverse (Group 2) challenge viruses, resulted in a reduction in CD4+ lymphocytes and an increase in CD8+ lymphocytes. Proviral loads were similar in both study groups, peaking by 10 weeks post-infection, a higher plateau (set-point) being achieved and maintained in study Group 1. Marked differences in the ability of individual viral variants to replicate were noted in Group 2; those most similar to GL8 achieved higher viral loads while variants such as the chimaeras bearing the B14 and B28 Envs grew less well. The defective replication of these variants was not due to suppression by the humoral immune response as virus neutralising antibodies were not elicited within the study period. Similarly, although potent cellular immune responses were detected against determinants in Env, no qualitative differences were revealed between animals infected with either the clonal or the diverse inocula. However, in vitro studies indicated that the reduced replicative capacity of variants B14 and B28 in vivo was associated with altered interactions between the viruses and the viral receptor and co-receptor. The data suggest that viral variants with GL8-like characteristics have an early, replicative advantage and should provide the focus for future vaccine development
Modulation of the virus-receptor interaction by mutations in the V5 loop of feline immunodeficiency virus (FIV) following in vivo escape from neutralising antibody
<b>BACKGROUND:</b> In the acute phase of infection with feline immunodeficiency virus (FIV), the virus targets activated CD4+ T cells by utilising CD134 (OX40) as a primary attachment receptor and CXCR4 as a co-receptor. The nature of the virus-receptor interaction varies between isolates; strains such as GL8 and CPGammer recognise a "complex" determinant on CD134 formed by cysteine-rich domains (CRDs) 1 and 2 of the molecule while strains such as PPR and B2542 require a more "simple" determinant comprising CRD1 only for infection. These differences in receptor recognition manifest as variations in sensitivity to receptor antagonists. In this study, we ask whether the nature of the virus-receptor interaction evolves in vivo.<p></p>
<b>RESULTS:</b> Following infection with a homogeneous viral population derived from a pathogenic molecular clone, a quasispecies emerged comprising variants with distinct sensitivities to neutralising antibody and displaying evidence of conversion from a "complex" to a "simple" interaction with CD134. Escape from neutralising antibody was mediated primarily by length and sequence polymorphisms in the V5 region of Env, and these alterations in V5 modulated the virus-receptor interaction as indicated by altered sensitivities to antagonism by both anti-CD134 antibody and soluble CD134.<p></p>
<b>CONCLUSIONS:</b> The FIV-receptor interaction evolves under the selective pressure of the host humoral immune response, and the V5 loop contributes to the virus-receptor interaction. Our data are consistent with a model whereby viruses with distinct biological properties are present in early versus late infection and with a shift from a "complex" to a "simple" interaction with CD134 with time post-infection.<p></p>
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