Effect of the surface chemical composition and of added metal cation concentration on the stability of metal nanoparticles synthesized by pulsed laser ablation in water

Metal nanoparticles (NPs) made of gold, silver, and platinum have been synthesized by means of pulsed laser ablation in liquid aqueous solution. Independently from the metal nature, all NPs have an average diameter of 10 ± 5 nm. The ζ-potential values are:-62 ± 7 mV for gold,-44 ± 2 mV for silver and-58 ± 3 for platinum. XPS analysis demonstrates the absence of metal oxides in the case of gold and silver NPs. In the case of platinum NPs, 22% of the particle surface is ascribed to platinum oxidized species. This points to a marginal role of the metal oxides in building the negative charge that stabilizes these colloidal suspensions. The investigation of the colloidal stability of gold NPs in the presence of metal cations shows these NPs can be destabilized by trace amounts of selected metal ions. The case of Ag+ is paradigmatic since it is able to reduce the NP ζ-potential and to induce coagulation at concentrations as low as 3 μM, while in the case of K+ the critical coagulation concentration is around 8 mM. It is proposed that such a huge difference in destabilization power between monovalent cations can be accounted for by the difference in the reduction potential

The sensory ecology of speciation

In this chapter, we explore the potential influence of sensory ecology on speciation, including but not limited to the concept of sensory drive, which concerns the co-evolution of signals and sensory systems with the local environment. The sensory environment can influence individual fitness in a variety of ways, thereby affecting the evolution of both pre- and post-mating reproductive isolation. Previous work focused on sensory drive has undoubtedly advanced the field, but we argue that it may have also narrowed our understanding of the broader influence of the sensory ecology on speciation. Moreover, the clearest examples of sensory drive are largely limited to aquatic organisms, which may skew the influence of contributing factors. We review the evidence for sensory drive across environmental conditions, and in this context discuss the importance of more generalized effects of sensory ecology on adaptive behavioral divergence. Finally, we consider the potential of rapid environmental change to influence reproductive barriers related to sensory ecologies. Our synthesis illustrates the importance of sensory conditions for local adaptation and divergence in a range of behavioral contexts and extends our understanding of the interplay between sensory ecology and speciation

Imagens sociais de famílias com filhos em acolhimento e em contexto familiar: um estudo entre Brasil e Portugal

A literatura indica que as famílias de crianças e jovens em acolhimento institucional podem ser estigmatizadas socialmente, gerando um impacto negativo no seu bem-estar, na construção da sua identidade e no sucesso da intervenção familiar. No entanto, poucos estudos investigam empiricamente esta imagem social. Este estudo teve como objetivo analisar a imagem social das famílias de crianças e jovens em diferentes contextos em Portugal e no Brasil. Uma amostra de 378 participantes (176 portugueses e 202 brasileiros) foi solicitada a indicar cinco atributos de famílias de crianças e jovens em acolhimento institucional e outros cinco atributos de famílias de crianças e jovens em contexto familiar, de estatutos socioeconômicos baixo e médio. Os dados indicam que em ambos os países existe um predomínio de atributos negativos associados às famílias de crianças e jovens em acolhimento institucional e de estatuto socioeconômico baixo, e um predomínio de atributos positivos associados às famílias em contexto familiar de estatuto socioeconômico médio. Destaca-se a necessidade de intervenções, especialmente com profissionais que atuam junto a essa população, para conscientização sobre essas imagens sociais.info:eu-repo/semantics/publishedVersio

Exposure to Domestic and Community Violence and Subjective Well-Being in Adolescents

Abstract There is major exposure to domestic and community violence during adolescence, which has been negatively related to well-being. This work aimed to identify relationships between domestic and community violence and the levels of subjective well-being perceived by adolescents, considering sex and age. The participants were 426 adolescents from public schools in the south of Brazil; 62% were girls, with a mean age of 14.91 years old ( SD = 1.65), who answered one instrument about exposure to violence and another about well-being. Results indicated greater domestic violence exposure among girls and greater community exposure among boys. The age range from 16 to 18 years old was the most exposed to domestic violence. Boys reported greater well-being and less negative affect. Differences in violence exposure may be related to roles of gender in our society. Well-being promotion is highlighted as a resource for confronting violence among adolescents

The diversification of Heliconius butterflies: what have we learned in 150 years?

Research into Heliconius butterflies has made a significant contribution to evolutionary biology. Here, we review our understanding of the diversification of these butterflies, covering recent advances and a vast foundation of earlier work. Whereas no single group of organisms can be sufficient for understanding life's diversity, after years of intensive study, research into Heliconius has addressed a wide variety of evolutionary questions. We first discuss evidence for widespread gene flow between Heliconius species and what this reveals about the nature of species. We then address the evolution and diversity of warning patterns, both as the target of selection and with respect to their underlying genetic basis. The identification of major genes involved in mimetic shifts, and homology at these loci between distantly related taxa, has revealed a surprising predictability in the genetic basis of evolution. In the final sections, we consider the evolution of warning patterns, and Heliconius diversity more generally, within a broader context of ecological and sexual selection. We consider how different traits and modes of selection can interact and influence the evolution of reproductive isolation.RMM is funded by a Junior Research Fellowship at King’s College, Cambridge. KMK is supported by the Balfour Studentship, University of Cambridge, SHMa by a Research Fellowship at St John's College, Cambridge, and SHMo by a Research Fellowship from the Royal Commission for the Exhibition of 1851. Our work on Heliconius has been additionally supported by the Agence Nationale de la Recherche (France), the Biology and Biotechnology Research Council (UK), the British Ecological Society, the European Research Council, the Natural Environment Research Council (UK), and the Smithsonian Tropical Research Institute.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/jeb.1267

Psychological Indicators and Perceptions of Adolescents in Residential Care

Abstract The institutionalization of adolescents has been mentioned in the literature with positive and negative aspects. This study investigated 61 adolescents in residential care aiming to evaluate psychological problems and perceptions related to the care, using interviews and the YSR. Data was evaluated using quantitative and qualitative analysis, using gender, age and length of institutionalization as variables. Results indicated clinical scores for psychological problems, except for externalizing problems, in younger girls recently taken into care and older boys institutionalized for longer periods. The perceptions about the care were negative or indifferent; elements of positivity were expressed by adolescents institutionalized for longer periods. Instability in the permanence in the care service and the reasons for having been taken into care were manifested with psychological distress. There were few contacts with the family of origin; the adolescents mentioned the importance of their families and the desire to leave the institution. Members of the institutional teams were indicated as sources of care and protection. This study reflects the challenges for the positive development of this population

Overview of the techniques used for the study of non-terrestrial bodies: Proposition of novel non-destructive methodology

Meteorites and impact glasses have been largely analysed using different techniques, but most studies have been focused on their geologicalemineralogical characterization and isotopic ratios, mainly of a destructive nature. However, much more information can be gained by applying novel non-destructive analytical procedures and techniques that have been scarcely used to analyse these materials. This overview presents some new methodologies to study these materials and compares these new approaches with the commonly used ones. Techniques such as X-Ray Fluorescence (XRF) and Laser Induced Breakdown Spectroscopy (LIBS), for elemental characterization, the hyphenated Raman spectroscopy- SEM/EDS and the combination of them, allow extracting simultaneous information from elemental, molecular and structural data of the studied sample; furthermore, the spectroscopic image capabilities of such techniques allow a better understanding of the mineralogical distribution. © 2017 Elsevier B.V. All rights reserved.Ministerio de Economía, Industria y Competitividad (project ESP2014-56138-C3-2-R