Increase in environmental temperature affects exploratory behaviour, anxiety and social preference in Danio rerio

The aim of this work is to investigate the effect of a temperature increase on the behaviour of adult zebrafish (Danio rerio) maintained for 21 days at 34 °C (treatment) and 26 °C (control). The temperatures chosen are within the vital range of zebrafish and correspond to temperatures that this species encounters in the natural environment. Previous results showed that the same treatment affects the brain proteome and the behaviour of adult zebrafish by producing alterations in the proteins involved in neurotransmitter release and synaptic function and impairing fish exploratory behaviour. In this study, we have investigated the performance of treated and control zebrafish during environmental exploration by using four behavioural tests (novel tank diving, light and dark preference, social preference and mirror biting) that are paradigms for assessing the state of anxiety, boldness, social preference and aggressive behaviour, respectively. The results showed that heat treatment reduces anxiety and increases the boldness of zebrafish, which spent more time in potentially dangerous areas of the tank such as the top and the uncovered bright area and at a distance from the social group, thus decreasing protection for the zebrafish. These data suggest that the increase in ambient temperature may compromise zebrafish survival rate in the natural environment

Mare Indicum Temps et espacesd’une autre modernité

Dans les dernières années, le corpus croissant d'études sur l'Océan Indien a soulevé bien des questions de méthodologie, mais aussi de nombreuses possibilités pour la recherche comparative. Le colonialisme a été un facteur évident pour donner unité à l'espace de l'Océan Indien. La religion était un autre domaine important de l'interaction. Les questions qui se posent quant à la nature et la dynamique de ces formes historiques de cohésion sont nombreux. Comment, par exemple, les migrations et les expériences de résistance anticoloniale ont façonné les subjectivités modernes dans l'Océan Indien? Comment pouvons-nous véritablement comprendre la notion de multiculturalisme dans l'Oéan Indien? Comment ont été forgées les identités dans l'Océan Indien, et quel rôle ont joué dans ce processus les réseaux religieux, commerciaux et culturels? De nouvelles études viennent de traiter certaines de ces questions en s'appuyant sur les conclusions émergeant du transnationalisme, l'universalisme et les régimes de circulation dans l'Océan Indien, en suggérant de nouveaux cadres théoriques pour comprendre et explorer de nouvelles méthodologies.The Indian Ocean has in recent years emerged as a vital area of study and analysis inviting attention from historians, anthropologists, social scientists and cultural studies scholars. The growing corpus of scholarship on the Indian Ocean has in turn raised issues of methodology and of potentialities for comparative research. The very nature of the discursive as well as the physical space of the Indian Ocean discourages a uni-disciplinary perspective and compels the researcher to consider both an expanded archive as well as a more inclusive paradigm of understanding. Colonialism was an obvious factor giving unity to the space of the Indian Ocean. Religion was another important field of cohesive interaction. The questions that arise as to the nature and dynamics of these historical and contemporary forms of cohesion are many. How for instance, did migrations and anti-colonial resistance experiences shape modern subjectivities in the Indian Ocean ? How can we meaningfully understand the notion of multi-culturalism in the Indian Ocean ? How were identities forged in the Indian Ocean, and what role did religious, commercial networks and media networks play in this process ? New studies intend to address some of these issues by drawing on emerging analysis of transnationalism, universalism and regimes of circulation in the Indian Ocean, by suggesting new theoretical frameworks for understanding and exploring new methodologies of study

Quantization for an elliptic equation of order 2m with critical exponential non-linearity

On a smoothly bounded domain $\Omega\subset\R{2m}$ we consider a sequence of positive solutions $u_k\stackrel{w}{\rightharpoondown} 0$ in $H^m(\Omega)$ to the equation $(-\Delta)^m u_k=\lambda_k u_k e^{mu_k^2}$ subject to Dirichlet boundary conditions, where $0<\lambda_k\to 0$. Assuming that $$\Lambda:=\lim_{k\to\infty}\int_\Omega u_k(-\Delta)^m u_k dx<\infty,$$ we prove that $\Lambda$ is an integer multiple of \Lambda_1:=(2m-1)!\vol(S^{2m}), the total $Q$-curvature of the standard $2m$-dimensional sphere.Comment: 33 page

Biomaterial-mediated factor delivery for spinal cord injury treatment

Spinal cord injury (SCI) is an injurious process that begins with immediate physical damage to the spinal cord and associated tissues during an acute traumatic event. However, the tissue damage expands in both intensity and volume in the subsequent subacute phase. At this stage, numerous events exacerbate the pathological condition, and therein lies the main cause of post-traumatic neural degeneration, which then ends with the chronic phase. In recent years, therapeutic interventions addressing different neurodegenerative mechanisms have been proposed, but have met with limited success when translated into clinical settings. The underlying reasons for this are that the pathogenesis of SCI is a continued multifactorial disease, and the treatment of only one factor is not sufficient to curb neural degeneration and resulting paralysis. Recent advances have led to the development of biomaterials aiming to promote in situ combinatorial strategies using drugs/biomolecules to achieve a maximized multitarget approach. This review provides an overview of single and combinatorial regenerative-factor-based treatments as well as potential delivery options to treat SCIs

A threshold phenomenon for embeddings of H0mH^m_0 into Orlicz spaces

We consider a sequence of positive smooth critical points of the Adams-Moser-Trudinger embedding of $H^m_0$ into Orlicz spaces. We study its concentration-compactness behavior and show that if the sequence is not precompact, then the liminf of the $H^m_0$-norms of the functions is greater than or equal to a positive geometric constant.Comment: 14 Page

Environmental temperature variation affects brain protein expression and cognitive abilities in adult zebrafish (Danio rerio): A proteomic and behavioural study.

Water temperature is an important environmental parameter influencing the distribution and the health of fishes and it plays a central role in ectothermic animals. The aim of this study is to determine the effects of environmental temperature on the brain proteome and the behavioural responses in zebrafish, a widely used animal model for environmental "omics" studies. Adult specimens of wild-type zebrafish were kept at 18 °C, 34 °C and 26 °C (control) for 21 days. Proteomic data revealed that several proteins involved in cytoskeletal organization, mitochondrial regulation and energy metabolism are differently regulated at the extreme temperatures. In particular, the expression of proteins associated to synapses and neurotransmitter release is down-regulated at 18 °C and 34 °C. In both thermal conditions, fish exhibited a reduced interest for the novel environment and an impairment of cognitive abilities during Y-Maze behavioural tests. The observed pathways of protein expression are possibly associated to functional alterations of the synaptic transmission that may result in cognitive functions impairment at central nervous system level as those revealed by behavioural tests. This study indicates that temperature variations can elicit biochemical changes that may affect fish health and behaviour. This combined approach provides insights into mechanisms supporting thermal acclimation and plasticity in fishes. SIGNIFICANCE: Environmental temperature variation may impact on all levels of biological life. Understanding the impact of thermal variation on the nervous system and animal behaviour is of primary importance since the results obtained can be applied from the ecological to the biomedical fields