129 research outputs found

    Gas phase structures and charge localization in small aluminum oxide anions: Infrared photodissociation spectroscopy and electronic structure calculations

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    We use cryogenic ion trap vibrational spectroscopy in combination with quantum chemical calculations to study the structure of mono- and dialuminum oxide anions. The infrared photodissociation spectra of D2-tagged AlO1-4− and Al2O3-6− are measured in the region from 400 to 1200 cm−1. Structures are assigned based on a comparison to simulated harmonic and anharmonic IR spectra derived from electronic structure calculations. The monoaluminum anions contain an even number of electrons and exhibit an electronic closed-shell ground state. The Al2O3-6− anions are oxygen-centered radicals. As a result of a delicate balance between localization and delocalization of the unpaired electron, only the BHLYP functional is able to qualitatively describe the observed IR spectra of all species with the exception of AlO3−. Terminal Al–O stretching modes are found between 1140 and 960 cm−1. Superoxo and peroxo stretching modes are found at higher (1120-1010 cm−1) and lower energies (850-570 cm−1), respectively. Four modes in-between 910 and 530 cm−1 represent the IR fingerprint of the common structural motif of dialuminum oxide anions, an asymmetric four-member Al–(O)2–Al ring

    Site-specific vibrational spectral signatures of water molecules in the magic H<sub>3</sub>O<sup>+</sup>(H<sub>2</sub>O)<sub>20</sub> and Cs<sup>+</sup>(H<sub>2</sub>O)<sub>20</sub> clusters

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    Theoretical models of proton hydration with tens of water molecules indicate that the excess proton is embedded on the surface of clathrate-like cage structures with one or two water molecules in the interior. The evidence for these structures has been indirect, however, because the experimental spectra in the critical H-bonding region of the OH stretching vibrations have been too diffuse to provide band patterns that distinguish between candidate structures predicted theoretically. Here we exploit the slow cooling afforded by cryogenic ion trapping, alongwith isotopic substitution, to quench water clusters attached to the H3O+ and Cs+ ions into structures that yield well-resolved vibrational bands over the entire 215- to 3,800-cm−1 range. The magic H3O+ (H2O)20 cluster yields particularly clear spectral signatures that can, with the aid of ab initio predictions, be traced to specific classes of network sites in the predicted pentagonal dodecahedron H-bonded cage with the hydronium ion residing on the surface

    Wild boar rooting intensity determines shifts in understorey composition and functional traits

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    In recent decades, the European populations of wild boar have grown substantially, as has the impact of this species, owing above all to its rooting activity. Our aim was to investigate the relationships between vascular plant understorey and wild boar rooting intensity. The questions we addressed are: does rooting intensity influence understorey species composition and diversity? Which functional traits are associated with different levels of rooting? We performed a comparative analysis of plant communities in areas with contrasting levels of rooting intensity within a Mediterranean deciduous lowland forest in central Italy. Besides comparing species composition and diversity, we tested the association between species traits and rooting levels through fourth-corner analysis. We found that contrasting levels of rooting were associated to different understorey species composition and evenness, while we observed no significant difference in species richness. In contrast with our expectations, sites with lower rooting returned i) lower evenness values and ii) a higher proportion of species characterized by traits related to resistance or response to herbivory, i.e., spinescence, clonality, endozoochory, underground storage organs, and low height values. Our findings suggest that current vegetation patterns partly depend on the legacy effect of past rooting disturbance, since the areas currently subjected to low rooting intensity were likely to be intensely rooted in the past. These areas may have developed a marked dominance of clonal thorny species that, in turn, inhibited further feeding activities by wild boar

    DIGISER. Digital Innovation in Governance and Public Service Provision

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    Digital Innovation Challenges In view of the increasingly intense pressures on the public sector to address the challenges of our time, governments and other public entities are gradually adopting digital innovation, seeking to promote quality public services. Digital technologies and capabilities create opportunities to re-organise public service inno- vation and delivery in ways that reduce cost and increase quality, proactiveness and citizen-centricity. Multilevel governance, networks and other collaboration systems (at local, regional, national and interna- tional level) are gaining importance as key drivers of this process of digital innovation and transformation. The link to the innovation ecosystem, including all sectors of activity, both private and public (e.g., academia, industry, business, citizens and governments) appears as fundamental in all phases of the creation, devel- opment, implementation and maintenance of public services and policy making. Information and communi- cation technologies are conceived as essential elements to support the creation and sustainability of these collaboration processes. In an era in which information gains relevance in the management of the territory and allows new power relations, the expectations of citizens are increasingly demanding and specific. Considering the develop- ments of recent years, such as the economic, social and health crises, the pressure placed on the resolution of global challenges is progressively transferred to the scope of cities. There are several elements that con- tribute to the importance of cities in the digital innovation transformation process namely buying- power, being closer to citizens and being able to work across different sectors. In fact, urban territories increasingly represent a greater number of citizens - in Europe, for example, they correspond to 75% of the population - have greater autonomy in management, worldwide they contribute to 80% of the global GDP and have the potential to provide a major contribution to the resolution of global challenges. The balance between change (promoted by the digital innovation strategies) and stability (driven by organi- sational inertia) needs to be handled carefully. The transformation process has to be based on a long-term strategy and to occur in a sustainable way, by focusing on learning experiences and knowledge and tech- nology transfer, while being sensitive to the local context to ensure improvement. At the European level, the Digital Transition has been considered a main goal for the next decade. The EU launched the European Green Deal and Europe Fit for the Digital Age, a twin initiative, which links green and digital transition. The vision for the EU ́s digital decade is reflected in the Digital Compass 2030 and includes 4 cardinal points: skills, government, infrastructure and Business. With the aim of having 100% of the key public services online by 2030, the digital compass ensures that digital will contribute in a positive way to improve citizens quality of life while reducing the resources spent. To support this vision, and by understanding the importance of community-led data-driven solutions and the potential of collaborative ap- proaches, several initiatives are being implemented. The Living-in.EU movement, for example, points out the European Way’ where multi-level governance and co-creation processes support the development of a cohesive digital Europe in the path towards digital transition. Another initiative contributing to this strategy is promoted by Open &amp; Agile Smart Cities which is connecting cities through Minimal Interoperability Mech- anisms (MIMs) - “a set of practical capabilities based on open technical specifications that allow cities and communities to replicate and scale solutions globally”. The MIMs contribute to the creation of the European Single Market by providing a common technical ground for the procurement and deployment of urban data platforms and end-to-end solutions in cities

    Skin tribology: Science friction?

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    The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems. In fact, effective solutions to friction and wear related questions can be found in our everyday life. An important part is related to skin tribology, as the human skin is frequently one of the interacting surfaces in relative motion. People seem to solve these problems related to skin friction based upon a trial-and-error strategy and based upon on our sense for touch. The question of course rises whether or not a trained tribologist would make different choices based upon a science based strategy? In other words: Is skin friction part of the larger knowledge base that has been generated during the last decades by tribology research groups and which could be referred to as Science Friction? This paper discusses the specific nature of tribological systems that include the human skin and argues that the living nature of skin limits the use of conventional methods. Skin tribology requires in vivo, subject and anatomical location specific test methods. Current predictive friction models can only partially be applied to predict in vivo skin friction. The reason for this is found in limited understanding of the contact mechanics at the asperity level of product-skin interactions. A recently developed model gives the building blocks for enhanced understanding of friction at the micro scale. Only largely simplified power law based equations are currently available as general engineering tools. Finally, the need for friction control is illustrated by elaborating on the role of skin friction on discomfort and comfort. Surface texturing and polymer brush coatings are promising directions as they provide way and means to tailor friction in sliding contacts without the need of major changes to the produc

    Cancer Biomarker Discovery: The Entropic Hallmark

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    Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases
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