1,721,188 research outputs found
Climate Change Threats to Stone Cultural Heritage: State of the Art of Quantitative Damage Functions and New Challenges for a Sustainable Future
Full text linkClimate change effects are a warning of the planetary crises threatening our collective future. This is a topic largely considered in the context of the environmental crisis, but we are now aware that climate change represents an increasingly alarming threat also in terms of the conservation of cultural heritage sites. Cultural heritage preservation should aim to an active environmental and societal strategy built on a renewed ethics of responsibility on long-term effects. This work provides a review of the current state of the art on the damage functions used for assessing the impacts of climate change on stone heritage surfaces. Within this framework, it introduces new concepts such as (i) the Loss of Details (LoD), in terms of the readability reduction of decorative elements and, subsequently, (ii) the Future Cultural Value (FCV), as the capacity of a cultural heritage to transmit its cultural message in its future appearance. The valorization of the historical legacy is a win–win solution to fix new planning tools and to achieve multiple goals oriented to a sustainable development for future generations. From this point of view, plaster cast galleries and museums play a crucial role in preserving cultural identity since they report a careful documentation of the original artifacts and monuments over the time
“A density functional study of the interaction between zinc ion in metalloproteinases and substituted hydroxamic acids”
No full text“Quantum chemistry study on the coordination of substituted hydroxamic acids with zinc ion in matrix metalloproteinases”
No full textHyperspherical symmetry of hydrogenic orbitals and recoupling coefficients among alternative bases
No full textFock's representation of momentum space hydrogenic orbitals in terms of harmonics on the hypersphere S(3) Of a four-dimensional space is extended to classify alternative bases. These orbitals are of interest for Sturmian expansions of use in atomic and molecular structure calculations and for the description of atoms in fields. Because of the correspondence between the S(3) manifold and the SU(2) group, new sum rules are established which are of relevance for the connection, not only among hydrogen atom orbitals in different bases, but also among the usual vector coupling coefficients and rotation matrix elements
“Binding of non-competitive ligands of the glutamate AMPA-receptor: a molecular mechanics investigation”
No full textAngular and hyperangular momentum momentum recoupling, harmonic superposition and Racah polynomials. A recursive algorithm
No full textGeneralized 6j symbols are defined in terms of orthonormalized Racah polynomials of a discrete variable and given explicitly as hypergeometric series. They extend the recoupling coefficients of ordinary angular moment-am algebra, including multiples of 1/4 as quantum numbers. A three-term recurrence relationship is exploited for extensive calculations and illustration of their properties. Their role is outlined as matrix elements for overlaps both between alternative spherical and hyperspherical harmonics and between alternative Sturmian sets, an important case being that of four-dimensional harmonics, which applies to the hydrogen atomic orbitals in momentum space
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Grafene Ossido ingegnerizzato con biomolecole per la deacidificazione di carte antiche contenenti inchiostri metallo-gallici
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