Adsorção de cádmio e chumbo em solos tropicais altamente intemperizados

O objetivo deste trabalho foi determinar a capacidade de adsorção de cádmio e de chumbo e avaliar a influência das propriedades dos solos sobre os parâmetros de adsorção desses elementos em solos tropicais altamente intemperizados. Foram utilizados quatro Latossolos e um Argissolo. Amostras de 1 g de solo foram agitadas por 16 horas, com soluções de CaCl2 0,01 mol L-1, às quais foram adicionadas 0, 10, 20, 30, 40, 60 e 80 µg mL-1 de cádmio e 0, 10, 20, 40, 60, 80, 100 e 120 µg mL-1 de chumbo na forma de nitrato. As quantidades adsorvidas foram determinadas mediante análise dos elementos no sobrenadante, e os dados foram ajustados às isotermas de Langmuir e de Freundlich. Os resultados experimentais ajustaram-se aos modelos estudados. A adsorção máxima de cádmio variou de 136 a 1.604 µg g-1 e a de chumbo, de 988 a 1.660 µg g-1. As energias de ligação variaram de 0,0036 a 0,0403 µg mL-1 e de 0,0282 a 1,0425 µg mL-1 para cádmio e chumbo, respectivamente. Os atributos dos solos correlacionados à adsorção de cádmio foram o pH e a capacidade de troca de cátions, e à adsorção de chumbo foram o pH e os níveis de óxidos de ferro e de alumínio.

The clc element and related genomic islands in Proteobacteria

Genomic islands are large DNA segments, present in most bacterial genome, that are acquired via horizontal gene transfer and contribute to the rapid bacterial evolution and adaptation of the host cell. Here we focus on the clc element (or ICEclc), a 103‑kb genomic island first discovered in Pseudomonas knackmussii B13, as a model of this diverse group of mobile genetic elements. ICEclc is normally integrated in the host bacterial chromosome but can excise and transfer to a new host by conjugation. In this chapter we review the basic features of ICEclc, the mechanisms of its life‑style as well as evolutionary relationships with other known and unknown elements in a variety of Proteobacteria.

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Sleep and waking are controlled by opposing interactions between circadian and homeostatic processes. A circadian process generated by the suprachiasmatic nucleus determines when sleep should occur, while a homeostatic process keeps track of time spent awake and asleep and signals sleep need or sleep propensity. Recent evidence indicates that these two processes employ many of the same set of genes. Herein, we review the basic concepts of the circadian and homeostatic regulation of sleep, and then outline the molecular components of circadian clock. We then discuss the evidence demonstrating a role of clock genes in sleep homeostasis in flies, mice, and humans. We conclude by suggesting that clock genes might be crucial for integrating homeostatic need, not only that of sleep but also of food intake and energy metabolism.

Comparative genomics of emerging pathogens in the Candida glabrata clade

BACKGROUND: Candida glabrata follows C. albicans as the second or third most prevalent cause of candidemia worldwide. These two pathogenic yeasts are distantly related, C. glabrata being part of the Nakaseomyces, a group more closely related to Saccharomyces cerevisiae. Although C. glabrata was thought to be the only pathogenic Nakaseomyces, two new pathogens have recently been described within this group: C. nivariensis and C. bracarensis. To gain insight into the genomic changes underlying the emergence of virulence, we sequenced the genomes of these two, and three other non-pathogenic Nakaseomyces, and compared them to other sequenced yeasts. RESULTS: Our results indicate that the two new pathogens are more closely related to the non-pathogenic N. delphensis than to C. glabrata. We uncover duplications and accelerated evolution that specifically affected genes in the lineage preceding the group containing N. delphensis and the three pathogens, which may provide clues to the higher propensity of this group to infect humans. Finally, the number of Epa-like adhesins is specifically enriched in the pathogens, particularly in C. glabrata. CONCLUSIONS: Remarkably, some features thought to be the result of adaptation of C. glabrata to a pathogenic lifestyle, are present throughout the Nakaseomyces, indicating these are rather ancient adaptations to other environments. Phylogeny suggests that human pathogenesis evolved several times, independently within the clade. The expansion of the EPA gene family in pathogens establishes an evolutionary link between adhesion and virulence phenotypes. Our analyses thus shed light onto the relationships between virulence and the recent genomic changes that occurred within the Nakaseomyces.

Morbillivirus glycoprotein expression induces ER stress, alters Ca2+ homeostasis and results in the release of vasostatin.

Although the pathology of Morbillivirus in the central nervous system (CNS) is well described, the molecular basis of neurodegenerative events still remains poorly understood. As a model to explore Morbillivirus-mediated CNS dysfunctions, we used canine distemper virus (CDV) that we inoculated into two different cell systems: a monkey cell line (Vero) and rat primary hippocampal neurons. Importantly, the recombinant CDV used in these studies not only efficiently infects both cell types but recapitulates the uncommon, non-cytolytic cell-to-cell spread mediated by virulent CDVs in brain of dogs. Here, we demonstrated that both CDV surface glycoproteins (F and H) markedly accumulated in the endoplasmic reticulum (ER). This accumulation triggered an ER stress, characterized by increased expression of the ER resident chaperon calnexin and the proapoptotic transcription factor CHOP/GADD 153. The expression of calreticulin (CRT), another ER resident chaperon critically involved in the response to misfolded proteins and in Ca(2+) homeostasis, was also upregulated. Transient expression of recombinant CDV F and H surface glycoproteins in Vero cells and primary hippocampal neurons further confirmed a correlation between their accumulation in the ER, CRT upregulation, ER stress and disruption of ER Ca(2+) homeostasis. Furthermore, CDV infection induced CRT fragmentation with re-localisation of a CRT amino-terminal fragment, also known as vasostatin, on the surface of infected and neighbouring non-infected cells. Altogether, these results suggest that ER stress, CRT fragmentation and re-localization on the cell surface may contribute to cytotoxic effects and ensuing cell dysfunctions triggered by Morbillivirus, a mechanism that might potentially be relevant for other neurotropic viruses.

Une étude clinique de l'activité de médecin de premier secours : vers une modélisation d'une profession complexe

Ce travail a pour objectif d'étudier l'évolution du métier de médecin de premier recours à la lumière du réel de son activité. Afin de pallier les lacunes de la littérature, nous proposons d'investiguer les perceptions et les pratiques rapportées de médecins de premier recours, considérant leur activité comme située dans un contexte spécifique. Un cadre théorique multiréférencé, intégrant les apports de Bischoff (2012), de la théorie de l'activité (Engeström et al., 1999), de l'ergonomie (Daniellou, 1996 ; Falzon, 2004a; Leplat, 1997) et de certains courants de la psychologie du travail (Curie et al., 1990 ; Curie, 2000b ; Malrieu, 1989) permet de tenir compte de la complexité du travail des médecins de premier recours. Une méthodologie mixte, alliant une approche qualitative par entretiens semi-structurés (n=20) à une approche quantitative par questionnaire (n=553), a été développée. Les résultats de l'analyse thématique des entretiens mettent en évidence trois thèmes majeurs : l'Evolution du métier (Thème 1), caractérisé par les changements perçus, les demandes des populations qui consultent et les paradoxes et vécus des médecins ; les Ajustements et supports (Thème 2) mis en place par les médecins pour faire face aux changements et aux difficultés de leur métier ; les Perceptions et les attentes par rapport au métier (Thème 3), mettant en avant des écarts perçus entre la formation et la réalité du métier. La partie quantitative permet de répondre aux questionnements générés à partir des résultats qualitatifs et de généraliser certains d'entre eux. Suite à l'intégration des deux volets de l'étude, nous présentons une nouvelle modélisation du métier de médecin de premier recours, soulignant son aspect dynamique et évolutif. Cette modélisation rend possible l'analyse de l'activité réelle des médecins, en tenant compte des contraintes organisationnelles, des paradoxes inhérents au métier et du vécu des médecins de premier recours. L'analyse des limites de cette étude ouvre à de nouvelles perspectives de recherche. A l'issue de ce travail, nous proposons quelques usages pragmatiques, qui pourront être utiles aux médecins de premier recours et aux médecins en formation, non seulement dans la réalisation de leur activité, mais également pour le maintien de leur équilibre et leur épanouissement au sein du métier. - This study aims to investigate the evolution of primary care physicians' work, in the light of the reality of their activity. In order to overcome the limitations of the literature, we propose to focus on primary care physicians' reported perceptions and practices, considering their activity as situated in a specific context. The theoretical framework refers to Bischoff (2012), Activity theory (Engeström et al., 1999), ergonomy (Daniellou, 1996; Falzon, 2004a; Leplat, 1997) and work psychology (Curie et al., 1990 ; Curie, 2000b ; Malrieu, 1989) and enables to take into account the complexity of primary care physicians' work. This mixed methods study proposes semi-structured interviews (n=20) and a questionnaire (n=553). Thematic analysis of interviews points out three major themes : Evolution of work (Theme 1) is characterised by perceived changes, patients' expectations and paradoxes ; Adjustments and supports (Theme 2), that help to face changes and difficulties of work ; Perceptions related to work, including differences between work reality as represented during medical education/training and actual work reality. Quantitative part of the study enables to answer questions generated from qualitative results and to generalise some of them. Integration of qualitative and quantitative results leads to a new modelling of primary care physicians ' work, that is dynamic and evolutionary. This modelling is useful to analyse the primary care physicians' activity, including organisational constraints, paradoxes of work and how primary care physicians are experiencing them. Despite its limitations, this study offers new research perspectives. To conclude, we state pragmatic recommendations that could be helpful to primary care physicians in private practice and junior doctors, in order to realise their activity, to maintain their balance and to sustain their professional fulfilment.

Neuroligin-1 links neuronal activity to sleep-wake regulation.

Maintaining wakefulness is associated with a progressive increase in the need for sleep. This phenomenon has been linked to changes in synaptic function. The synaptic adhesion molecule Neuroligin-1 (NLG1) controls the activity and synaptic localization of N-methyl-d-aspartate receptors, which activity is impaired by prolonged wakefulness. We here highlight that this pathway may underlie both the adverse effects of sleep loss on cognition and the subsequent changes in cortical synchrony. We found that the expression of specific Nlg1 transcript variants is changed by sleep deprivation in three mouse strains. These observations were associated with strain-specific changes in synaptic NLG1 protein content. Importantly, we showed that Nlg1 knockout mice are not able to sustain wakefulness and spend more time in nonrapid eye movement sleep than wild-type mice. These changes occurred with modifications in waking quality as exemplified by low theta/alpha activity during wakefulness and poor preference for social novelty, as well as altered delta synchrony during sleep. Finally, we identified a transcriptional pathway that could underlie the sleep/wake-dependent changes in Nlg1 expression and that involves clock transcription factors. We thus suggest that NLG1 is an element that contributes to the coupling of neuronal activity to sleep/wake regulation.

Estructura espacial de un ecotono bosque subalpino pastos alpinos en el Tessó de Son (Pirineos Centrales) formado por bandas altitudinales de árboles

El límite altitudinal del bosque y los pastos alpinos forman los límites inferior y superior del ecotono bosque subalpino-pastos alpinos, respectivamente. El objetivo es la descripción espacial de este ecotono, en un sitio poco afectado por perturbaciones humanas locales (Tessó, 42° 36' N, 01° 03' E), para inferir los procesos que generaron su estructura espacial. Este ecotono está compuesto por Pinus uncinata y su límite altitudinal se sitúa a -2350 m snm. Se midieron la localización (coordenadas x e y) y varias características (diámetros en la base -Db- y a 1,3 m -Dbh-, altura, edad estimada, etc.) para cada árbol dentro de una parcela rectangular (30 m x 140 m) paralela a la máxima pendiente y cruzando el ecotono. La estructura espacial se describió mediante cuatro grupos de técnicas:(i) análisis del patrón de puntos, (ii) análisis del patrón de superficies, (iii) detección y descripción de fronteras (lattice-wombling), y (iv) ordenación de 115 cuadrados de 6 m x 6 m en que se subdividió la parcela de acuerdo a su posición en el ecotono y al tipo de individuos de P. uncinata (adultos, jóvenes, vástagos, plántulas y muertos) y de plantas (arbustos y herbáceas) que contenían. El límite del bosque se sitúa bajo el límite forestal potencial marcado por la isoterma de 10 ºC para la temperatura media del mes más cálido. A lo largo de la pendiente, las plántulas de P. uncinata aparecen por encima del límite del árbol, donde predomina Dryas octopetala, mientras que los individuos grandes (adultos) aparecen cerca o dentro del bosque, con un sotobosque dominado por densas matas de Rhododendron ferrugineum acompañadas por Vaccinium myrtillus sobre un sustrato de materia orgánica. La ordenación confirma estos resultados colocando a los individuos muertos en una posición intermedia. La variación a lo largo del ecotono de diversas variables ...

Aludes de nieve. Riesgo actual y riesgo futuro.

Los aludes son fenómenos recurrentes que se producen con una gran variedad de situaciones nivo-meteorológicas. Las actuaciones para minimizar el riesgo son básicamente dos: la predicción temporal (boletín del peligro de aludes), que hay que mantener, y la predicción en el espacio (cartografías). El riesgo de ser afectado por un alud se percibe con total indefensión por la población cuando un alud de gran magnitud impacta sobre un edificio o una infraestructura. Por tanto, es necesaria una legislación del uso de suelo que obligue a considerar los riesgos naturales en la calificación de suelos no urbanizables, basada en mapas de inventario y peligrosidad. Así se puede proteger a la población no especialista frente a las amenazas naturales extremas. Respecto al cambio climático, el IPCC, en su Tercer Informe de Evaluación expone una serie de probables escenarios de cambio climático a escala global. En todos ellos se concluye que muy probablemente las temperaturas mínimas serán más altas (irán en aumento), habrá menos días fríos, días de heladas y olas de frío en casi todas las zonas continentales. esto va a conllevar la elevación de la isoterma de 0ºC hacia mayores altitudes y, por lo tanto, la elevación del límite del manto nivoso continuo durante el invierno hacia mayores altitudes. Respecto a la precipitación y también a escala global, no se puede concluir que vaya a haber un incremento positivo de los eventos de temporal extremos, por lo que no se puede concluir que vaya a haber una variación del número de aludes extremos. Respecto al riesgo futuro, en el mejor de los casos se van a seguir produciendo aludes de la misma o mayor magnitud y en los mismos lugares. El deterioro del bosque de protección es muy probable, por lo será necesaria una buena gestión forestal. La minimización del riesgo deberá basarse en una buena legislación y una buena gestión territorial.

The systemic control of circadian gene expression.

The mammalian circadian timing system consists of a central pacemaker in the brain's suprachiasmatic nucleus (SCN) and subsidiary oscillators in nearly all body cells. The SCN clock, which is adjusted to geophysical time by the photoperiod, synchronizes peripheral clocks through a wide variety of systemic cues. The latter include signals depending on feeding cycles, glucocorticoid hormones, rhythmic blood-borne signals eliciting daily changes in actin dynamics and serum response factor (SRF) activity, and sensors of body temperature rhythms, such as heat shock transcription factors and the cold-inducible RNA-binding protein CIRP. To study these systemic signalling pathways, we designed and engineered a novel, highly photosensitive apparatus, dubbed RT-Biolumicorder. This device enables us to record circadian luciferase reporter gene expression in the liver and other organs of freely moving mice over months in real time. Owing to the multitude of systemic signalling pathway involved in the phase resetting of peripheral clocks the disruption of any particular one has only minor effects on the steady state phase of circadian gene expression in organs such as the liver. Nonetheless, the implication of specific pathways in the synchronization of clock gene expression can readily be assessed by monitoring the phase-shifting kinetics using the RT-Biolumicorder.

In vivo imaging of the central and peripheral effects of sleep deprivation and suprachiasmatic nuclei lesion on PERIOD-2 protein in mice.

STUDY OBJECTIVES: That sleep deprivation increases the brain expression of various clock genes has been well documented. Based on these and other findings we hypothesized that clock genes not only underlie circadian rhythm generation but are also implicated in sleep homeostasis. However, long time lags have been reported between the changes in the clock gene messenger RNA levels and their encoded proteins. It is therefore crucial to establish whether also protein levels increase within the time frame known to activate a homeostatic sleep response. We report on the central and peripheral effects of sleep deprivation on PERIOD-2 (PER2) protein both in intact and suprachiasmatic nuclei-lesioned mice. DESIGN: In vivo and in situ PER2 imaging during baseline, sleep deprivation, and recovery. SETTINGS: Mouse sleep-recording facility. PARTICIPANTS: Per2::Luciferase knock-in mice. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Six-hour sleep deprivation increased PER2 not only in the brain but also in liver and kidney. Remarkably, the effects in the liver outlasted those observed in the brain. Within the brain the increase in PER2 concerned the cerebral cortex mainly, while leaving suprachiasmatic nuclei (SCN) levels unaffected. Against expectation, sleep deprivation did not increase PER2 in the brain of arrhythmic SCN-lesioned mice because of higher PER2 levels in baseline. In contrast, liver PER2 levels did increase in these mice similar to the sham and partially lesioned controls. CONCLUSIONS: Our results stress the importance of considering both sleep-wake dependent and circadian processes when quantifying clock-gene levels. Because sleep deprivation alters PERIOD-2 in the brain as well as in the periphery, it is tempting to speculate that clock genes constitute a common pathway mediating the shared and well-known adverse effects of both chronic sleep loss and disrupted circadian rhythmicity on metabolic health.

An interactive web-GIS tool for risk analysis: a case study in the Fella River basin, Italy

This paper presents a prototype of an interactive web-GIS tool for risk analysis of natural hazards, in particular for floods and landslides, based on open-source geospatial software and technologies. The aim of the presented tool is to assist the experts (risk managers) in analysing the impacts and consequences of a certain hazard event in a considered region, providing an essential input to the decision-making process in the selection of risk management strategies by responsible authorities and decision makers. This tool is based on the Boundless (OpenGeo Suite) framework and its client-side environment for prototype development, and it is one of the main modules of a web-based collaborative decision support platform in risk management. Within this platform, the users can import necessary maps and information to analyse areas at risk. Based on provided information and parameters, loss scenarios (amount of damages and number of fatalities) of a hazard event are generated on the fly and visualized interactively within the web-GIS interface of the platform. The annualized risk is calculated based on the combination of resultant loss scenarios with different return periods of the hazard event. The application of this developed prototype is demonstrated using a regional data set from one of the case study sites, Fella River of northeastern Italy, of the Marie Curie ITN CHANGES project.

Precursor nanoscale modulations in ferromagnets: Modeling and thermodynamic characterization

Using a Ginzburg-Landau model for the magnetic degrees of freedom with coupling to disorder, we demonstrate through simulations the existence of stripelike magnetic precursors recently observed in Co-Ni-Al alloys above the Curie temperature. We characterize these magnetic modulations by means of the temperature dependence of local magnetization distribution, magnetized volume fraction, and magnetic susceptibility. We also obtain a temperature-disorder strength phase diagram in which a magnetic tweed phase exists in a small region between the paramagnetic and dipolar phases.

Origin of magnetic and magnetoelastic tweedlike precursor modulations in ferroic materials

Based on experimental observations of modulated magnetic patterns in a Co0.5Ni0.205Ga0.295 alloy, we propose a model to describe a (purely) magnetic tweed and a magnetoelastic tweed. The former arises above the Curie (or Nel) temperature due to magnetic disorder. The latter results from compositional fluctuations coupling to strain and then to magnetism through the magnetoelastic interaction above the structural transition temperature. We discuss the origin of purely magnetic and magnetoelastic precursor modulations and their experimental thermodynamic signatures.

Magnetic and transport properties of InGaAs quantum wells with Mn

In the present work structural, magnetic and transport properties of InGaAs quantum wells (QW) prepared by MBE with an remote Mn layer are investigated. By means of high-resolution X-ray diffractometry the structure of the samples is analyzed. It is shown that Mn ions penetrate into the QW. Influence of the thickness of GaAs spacer and annealing at 286 ºС on the properties of the system is shown. It is shown that annealing of the samples led to Mn activation and narrowing of the Mn layer. Substantial role of 2D holes in ferromagnetic ordering in Mn layer is shown. Evidence for that is observation of maximum at 25 – 55 K on the resistivity temperature dependence. Position of maximum, which is used for quantitative assessment of the Curie temperature, correlates with calculations of the Curie temperature for structures with indirect interaction via 2D holes’ channel. Dependence of the Curie temperature on the spacer thickness shows, that creation of applicable spintronic devices needs high-precision equipment to manufacture extra fine structures. The magnetotransport measurements show that charge carrier mobility is very low. This leads to deficiency of the anomalous Hall effect. At the same time, magnetic field dependences of the magnetization at different temperatures demonstrate that systems are ferromagnetically ordered. These facts, most probably, give evidence of presence of the ferromagnetic MnAs clusters.