The Sea Urchin Embryo: A Model for Studying Molecular Mechanisms Involved in Human Diseases and for Testing Bioactive Compounds

Most of the current knowledge concerning fundamental genetic mechanisms, evolutionary processes and development, cellular physiology, and pathogenesis comes from studies of different animal model systems. Whereas mice, rats, and other small mammals are generally thought of as the typical model systems used by researchers in biomedical studies, aquatic models including both freshwater and marine organisms have long proved to be essential for the study of basic biological processes. For over a century, biologists have used the sea urchin embryo as a prototype for the investigation of developmental mechanisms that contribute to building the embryo body plan. Here we highlight the contribution of the sea urchin embryo as a simple model for studying aging and age-associated neurodegenerative diseases, as well as the pathways and mechanisms involved in cell survival and death. Moreover, we point out the role of this embryonic system as a potent and affordable tool for learning about developmental effects and toxicity responses to environmental contaminants and chemical compounds

The influence of aquatic humic substances characteristics on the coagulation efficiency using ferric chloride

The aim of this study was to verify the influence of the apparent molecular size of aquatic humic substances on the effectiveness of coagulation with ferric chloride. Coagulation-filtration tests using jar test and bench-scale sand filters were carried out on samples of water with true color of approximately 100 Hazen units, prepared with aquatic humic substances of different molecular sizes (F1: < 0.45 µm, F2: 100 kDa - 0.45 µm, F3: 30 - 100 kDa and F4': < 30 kDa). For the water samples with lower apparent molecular size fractions, greater dosages of coagulant was needed to remove the color around 5.0 Hanzen units, mainly because these water samples contain higher concentrations of fulvic acids, which exhibited a larger number of negatively-charged groups.Conselho Nacional de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Pesquisa e Desenvolvimento (CNPq

A Novel Computer-Based Set-Up to Study Movement Coordination in Human Ensembles

Existing experimental works on movement coordination in human ensembles mostly investigate situations where each subject is connected to all the others through direct visual and auditory coupling, so that unavoidable social interaction affects their coordination level. Here, we present a novel computer-based set-up to study movement coordination in human groups so as to minimize the influence of social interaction among participants and implement different visual pairings between them. In so doing, players can only take into consideration the motion of a designated subset of the others. This allows the evaluation of the exclusive effects on coordination of the structure of interconnections among the players in the group and their own dynamics. In addition, our set-up enables the deployment of virtual computer players to investigate dyadic interaction between a human and a virtual agent, as well as group synchronization in mixed teams of human and virtual agents. We show how this novel set-up can be employed to study coordination both in dyads and in groups over different structures of interconnections, in the presence as well as in the absence of virtual agents acting as followers or leaders. Finally, in order to illustrate the capabilities of the architecture, we describe some preliminary results. The platform is available to any researcher who wishes to unfold the mechanisms underlying group synchronization in human ensembles and shed light on its socio-psychological aspects

Impairing Otp homeodomain function in oral ectoderm cells affects skeletogenesis in sea urchin embryos

AbstractIn the sea urchin embryo skeletogenesis is the result of a complex series of molecular and cellular events that coordinate the morphogenetic process. Past and recent evidence strongly indicate that skeletal initiation and growth are strictly dependent on signals emanating from the oral ectodermal wall. As previously suggested, Orthopedia (Otp), a homeodomain-containing transcription factor specifically expressed in a small subset of oral ectoderm cells, might be implicated in this signalling pathway. In this study, we utilize three different strategies to address the issue of whether Otp is an upstream regulator of sketelogenesis. We describe the effects of microinjection of Otp morpholino-substituted antisense oligonucleotides and dominant-negative Otp-engrailed mRNA in Paracentrotus lividus embryos. We demonstrate that inhibition of Otp expression completely abolishes skeletal synthesis. By contrast, coinjection of Otp mRNA and the morpholino antisense oligonucleotide specifically rescues the skeletogenic program. In addition, localized ectodermal expression of the Otp-GFP fusion gene construct driven by the hatching enzyme promoter, induces ectopic and abnormal spiculogenesis. We further show that an indirect target of this homeoprotein is the skeletogenic specific gene SM30, whose expression is known to be under the strict control of the oral ectoderm territory. Based on these results, we conclude that Otp triggers the ectoderm-specific signal that promotes skeletogenesis

Leadership emergence in walking groups

Understanding the mechanisms underlying the emergence of leadership in multi-agent systems is still under investigation in many areas of research where group coordination is involved. While leadership has been mostly investigated in the case of animal groups, only a few works address the problem of leadership emergence in human ensembles, e.g. pedestrian walking, group dance. In this paper we study the emergence of leadership in the specific scenario of a small walking group. Our aim is to unveil the main mechanisms emerging in a human group when leader or follower roles are not designated a priori. Two groups of participants were asked to walk together and turn or change speed at self-selected times. Data were analysed using time-dependent cross correlation to infer leader-follower interactions between each pair of group members. The results indicate that leadership emergence is due both to contextual factors, such as an individual's position in the group, and to personal factors, such as an individual's characteristic locomotor behaviour. Our approach can easily be extended to larger groups and other scenarios such as team sports and emergency evacuations

Modelling and control for bounded synchronization in multi-terminal VSC-HVDC transmission networks

© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The extension and size of the power grid is expected to increase in the near future. Managing such a system presents challenging control problems that, so far, have been approached with classical control techniques. However, large scale systems of interconnected nodes fall within the framework of the emerging field of complex networks. This paper models multi-terminal VSC-HVDC systems as a complex dynamical network, and derives conditions ensuring bounded synchronization of its trajectories for a family of controllers. The obtained results are validated via numerical simulations.Postprint (author's final draft

Eficiência do tratamento de água em ciclo completo na remoção do Diclofenaco Sódico / Efficiency of water treatment in the complete cycle in the removal of Sodic Diclofenac

A presença de fármacos em águas de abastecimento tem sido alvo de estudos nas áreas de saúde pública e ambiental devido principalmente à sua persistência no meio ambiente e aos efeitos adversos causados à comunidade aquática e à saúde humana. Dentre os fármacos comumente identificados em águas de abastecimento, destacam-se os anti-inflamatórios, especialmente o diclofenaco, por ser um dos mais consumidos no Brasil e no mundo.  Neste contexto, foram realizados ensaios em ciclo completo utilizando equipamento de jarteste e filtros, em escala laboratorial, preenchidos com areia (FLAs) para verificar a remoção do diclofenaco sódico (DCF) empregando-se o tratamento de água em ciclo completo (coagulação, floculação, sedimentação, filtração em areia e pós-cloração). Verificou-se que não houve remoção de DCF nas etapas de coagulação, floculação, sedimentação e filtração em areia. Houve remoção de 36 % e de 97 % do DCF após 30 min e 24 h do término da pós-cloração com 5 mg L-1 de cloro, respectivamente. 

Vita della serva di Dio svor Giovanna Maria della Santissima Trinita : monaca carmelitana scalza del Monastere delle Sante Anna e Teresa ...

Copia digital : Junta de Castilla y León. Consejería de Cultura y Turismo, 2014Sign.: [cruz griega]4, 2 [cruz griega]4, A-Z4, 2A-2Z4, 3A-3F4