23 research outputs found

    Chromoselective access to Z- or E- allylated amines and heterocycles by a photocatalytic allylation reaction

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    The most useful strategies for the alkylation of allylic systems are related to the Tsuji–Trost reaction or the use of different Lewis acids. Herein we report a photocatalytic approach for the allylation reaction of a variety of nucleophiles, such as heteroarenes, amines and alcohols. This method is compatible with a large variety of pyrroles and indoles, containing different substituents such as electron-withdrawing and electron-donating groups, unprotected nitrogen atoms and bromo derivatives. Moreover, this methodology enables the chromoselective synthesis of Z- or E-allylated compounds. While the use of UV-light irradiation has allowed the synthesis of the previously inaccessible Z-allylated products, E-isomers are prepared simply by changing both the light source to the visible region, and the catalytic system. Based on mechanistic and photochemical proofs, laser flash photolysis studies and DFT calculations, a rational mechanism is presentedFinancial support from the Spanish Government (CTQ2015-64561-R), CCC-UAM (computing time), and ERC (ERC-CG, 647550, 648319) is acknowledged. L.M., R.P-R, and R.C. thank CAM for the “Atracción de Talento” fellowship. The authors thank “Comunidad de Madrid” and European Structural Funds for their financial support to FotoArt-CM project (S2018/NMT-4367). We thank Miguel Ángel Miranda for helpful discussions about photochemical mechanism

    Mesityl or imide acridinium photocatalysts: accessible versus inaccessible charge-transfer states in photoredox catalysis

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    A study on C9-imide acridinium photocatalysts with enhanced photoredox catalytic activity with respect to the well-established C9-mesityl acridinium salt is presented. The differences observed rely on the diverse accessibility of singlet chargetransfer excited states, which have been proven by CASPT2/CASSCF calculations, fluorescence and quenching studiesThe Boehringer Ingelheim Stiftung (Exploration Grant), the Deutsche Forschungsgemeinschaft (DFG), Spanish Government (CTQ2015-64561-R, CTQ2015-63997-C2, ENE2016-79608-C2-1-R) and Community of Madrid (2016-T1/AMB-1275) are acknowledged. The authors wish to thank ’’Comunidad de Madrid’’ for its support to the FotoArt-CM Project (S2018/NMT-4367) through the Program of R&D activities between research groups in Technologies 2013, co-financed by European Structural Fun

    Learning to make informed health choices : Protocol for a pilot study in schools in Barcelona

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    The Informed Health Choices (IHC) project has developed learning resources to teach primary school children (10 to 12-year-olds) to assess treatment claims and make informed health choices. The aim of our study is to explore both the students' and teachers' experience when using these resources in the context of Barcelona (Spain). During the 2019-2020 school year, we will conduct a pilot study with 4 th and 5 th-year primary school students (9 to 11-year-olds) from three schools in Barcelona. The intervention in the schools will include: 1) assessment of the IHC resources by the teachers before the lessons, 2) non-participatory observations during the lessons, 3) semi-structured interviews with the students after a lesson, 4) assessment of the lessons by the teachers after a lesson, 5) treatment claim assessment by the students at the end of the lessons, and 6) assessment of the IHC resources by the teachers at the end of the lessons. We will use ad hoc questionnaires and guides to register the data. We will perform a quantitative and qualitative analysis of the data to explore understandability, desirability, suitability, usefulness, facilitators and barriers of the resources. The most relevant results will be discussed and some recommendations on how to use, how to adapt (if needed), and how to implement the IHC resources to this context will be agreed. The findings of the contextualization activities could inform the design of a cluster-randomised trial, to determine the effectiveness of the IHC resources in this context prior to scaling-up its use. The study protocol has obtained an approval exemption from the Ethics Committee of the Hospital de la Santa Creu i Sant Pau (Barcelona, Spain)

    Social Participation Network: Linking things, services and people to support participatory processes

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    International audienceDigital technologies have impacted almost every aspect of our society, including how people participate in activities that matter to them. Indeed, digital participation allows people to be involved in different societal activities at an unprecedented scale through the use of Information and Communication Technologies (ICT). Still, enabling participation at scale requires making it seamless for people to: interact with a variety of software platforms, get information from connected physical objects and software services, and communicate and collaborate with their peers. Toward this objective, this paper introduces and formalizes the concept of Social Participation Network, which captures the diverse participation relationships-between people, digital services and connected things-supporting participatory processes. The paper further presents the design of an associated online service to support the creation and management of Social Participation Networks. The design advocates the instantiation of Social Participation Networks within distinct participation contexts-spanning, e.g., private institutions, neighbor communities, and governmental institutions-so that the participants' information and contributions to participation remain isolated and private within the given context

    El barranc de la Boella de la Canonja (TarragonĂšs) revisitat en la intervenciĂł arqueolĂČgica preventiva de l'any 2007

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    El barranc de la Boella de la Canonja Ă©s un jaciment descobert en el primer terç del segle XX. Cinquanta anys desprĂ©s de la seva descoberta, la publicaciĂł d'aquest jaciment pels senyors R. Capdevila i S. Vilaseca va permetre actualitzar l'escĂ s coneixement de la bioestratigrafia del quaternari del Camp de Tarragona (Vilaseca, 1973). Tal com assenyala el mateix S. Vilaseca, la presĂšncia de fĂČssils de mamĂ­fers en el barranc va ser donada a conĂšixer per J. R. Bataller en la memĂČria explicativa del segon mapa geolĂČgic del full 473 de l'IGME corresponent a Tarragona (Bataller, 1935). El mateix S. Vilaseca apunta altres descobertes de mamĂ­fers ressenyades en el Camp de Tarragona, com la nota de Faura i Sans sobre un fragment de molar de proboscidi que HarlĂ© determinaria com Elephas meridionalis el mateix any (Faura i Sans, 1920; HarlĂ©, 1920). Aquesta resta va ser enviada per A. RomanĂ­, aleshores director del Museu Balaguer de Vilanova i la GeltrĂș, a qui li van fer arribar des d'unes pedreres del Port de Tarragona. Els treballs geolĂČgics de M. Faura i Sans, J.R. Bataller i S. Vilaseca durant el primer quart del segle XX protagonitzaren el desenvolupament de la geologia, la paleontologia i la prehistĂČria en el marc del Servei del Mapa de la Mancomunitat de Catalunya

    Binding the Smart City Human-Digital System with Communicative Processes

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    This chapter will explore the dynamics of power underpinning ethical issues within smart cities via a new paradigm derived from Systems Theory. The smart city is an expression of technology as a socio-technical system. The vision of the smart city contains a deep fusion of many different technical systems into a single integrated “ambient intelligence”. ETICA Project, 2010, p. 102). Citizens of the smart city will not experience a succession of different technologies, but a single intelligent and responsive environment through which they move. Analysis of such an environment requires a framework which transcends traditional ontologically-based models in order to accommodate this deep fusion. This chapter will outline a framework based on Latour’s Actor-Network Theory and Luhmann’s treatment of society as an autopoetic system. We shall use this framework to map the influence of relevant factors on ethical issues, irrespective of their composition or type. For example, under this treatment, both human praxis and technical design can be viewed as comparable tools of domination. This chapter will provide a framework for the analysis of relations between any elements of the smart city, ranging from top-level urban management processes down to individual device operations. While we will illustrate the use of this schema through examination of ethical issues arising from power dynamics within the smart city, it is intended that this example will demonstrate the wider utility of the model in general

    Cultural or ecological sustainability? The effect of cultural change on Sabal palm management among the lowland Maya of Mexico

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    Sabal palm has been used for thatching the traditional Maya house for over 3000 yr. The great importance of this resource has promoted its management within home gardens. Although traditionally managed populations in home gardens are capable of ecological long-term persistence, the impact of cultural change on sustainable resource management is poorly understood. By means of interviews in 108 households, we obtained information about Sabal management practices, leaf demand, and sociocultural data. Density and size structure of the palm populations in the respective home gardens were also measured. By means of principal components analysis, the sociocultural data were summarized into a cultural change index, which was then statistically related to palm density, size structure, leaf demand, and management practices. Leaf demand along the cultural change gradient was estimated. Sabal populations were affected by the cultural change index. Palm density and the proportion of harvestable individuals were higher in the more traditional households. The number of management practices decreased, and the probability of felling adult palms increased with cultural change. As a result, the percentage of the total leaf demand satisfied by home garden production diminished from 118.2–69.4% as cultural change increased. Traditional practices seem oriented to increasing the palm availability. Seed sowing and the protection of seedlings and adults affect the life stages with the largest impact on the population growth rate, as measured through sensitivity analysis. This means that abandoning traditional practices and felling adults more frequently should reduce rapidly, which is consistent with the low palm density observed in less traditional households. The application of demographic models to Sabal tells us that traditional management warrants the persistence of the resource as long as the current conditions remain unchanged. In contrast, our data show that Sabal management may not be sustainable from a cultural perspective, since the cultural attitudes that affect palm management and demand change over time. Both approaches assess the same problem from different viewpoints reaching different but complementary conclusions. In this study, we propose new methods that integrate the ecological and cultural processes, which affect the sustainable management of the natural resources
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