Mediated modeling of the impacts of enhanced UV-B radiation on ecosystem services

This article describes the use of group model building to facilitate interaction with stakeholders, synthesize research results and assist in the development of hypotheses about climate change at the global level in relation to UV-B radiation and ecosystem service valuation. The objective was to provide a platform for integration of the various research components within a multidisciplinary research project as a basis for interaction with stakeholders with backgrounds in areas other than science. An integrated summary of the scientific findings, along with stakeholder input, was intended to produce a bridge between science and policymaking. We used a mediated modeling approach that was implemented as a pilot project in Ushuaia, Argentina. The investigation was divided into two participatory workshops: data gathering and model evaluation. Scientists and the local stakeholders supported the valuation of ecosystem services as a useful common denominator for integrating the various scientific results. The concept of economic impacts in aquatic and marsh systems was represented by values for ecosystem services altered by UV-B radiation. In addition, direct local socioeconomic impacts of enhanced UV-B radiation were modeled, using data from Ushuaia. We worked with 5 global latitudinal regions, focusing on net primary production and biomass for the marine system and on 3 plant species for the marsh system. Ecosystem service values were calculated for both sectors. The synthesis model reflects the conclusions from the literature and from experimental research at the global level. UV-B is not a significant stress for the marshes, relative to the potential impact of increases in the sea level. Enhanced UV-B favors microbial dynamics in marine systems that could cause a significant shift from primary producers to bacteria at the community level. In addition, synergetic effects of UV-B and certain pollutants potentiate the shift to heterotrophs. This may impact the oceanic carbon cycle by increasing the ratio of respiratory to photosynthetic organisms in surface waters and, thus, the role of the ocean as a carbon sink for atmospheric CO2. In summary, although changes in the marine sector due to anthropogenic influences may affect global climate change, marshes are expected to primarily be affected by climate change.     

Non-interacting dimer kinetics in hypercubic lattices

The exact formulation of the kinetic of dimer in hypercubic lattices is developed in the framework of the kinetic lattice gas model. The so-called local evolution rules are used to obtain the hierarchy of equation of motion for the correlation functions where processes like adsorption and desorption are included. The hierarchy of equations are truncated using a mean field (m, n) closures which allows the analytical treatment of the system. A general expression for non-interacting dimer isotherm and two particle correlation functions are obtained in hypercubic lattices.     

Totally positive functions through nonstationary subdivision schemes

In this paper a new class of nonstationary subdivision schemes is proposed to construct functions having all the main properties of B-splines, namely compact support, central symmetry and total positivity. We show that the constructed nonstationary subdivision schemes are asympotically equivalent to the stationary subdivision scheme associated with a B-spline of suitable degree, but the resulting limit function has smaller support than the B-spline although keeping its regularity.     

Controlling Type II Error While Constructing Triple Sampling Fixed Precision Confidence Intervals for the Normal Mean

The rationale and methodology for estimating a mean with a fixed width confidence interval through sampling in three stages are extended to cover the additional problem of testing hypotheses concerning shifts in the mean with controlled Type II error. The coverage probability and operating characteristic function of the confidence interval based on the integrated approach are derived and compared with those of the usual triple sampling confidence interval. The extended methodology leads to better coverage probability and uniformly better Type II error probabilities. Achieving the additional objective of controlling Type II error inevitably implies a two- to threefold increase in the required optimal sample size. Some suggestions for dealing with this apparent limitation are discussed from a practical viewpoint. It is recommended that an integrated approach to estimation and testing based on confidence intervals be incorporated in the design stage for credible inferences.     

Tracing the biological origin of animal glues used in paintings through mitochondrial DNA analysis

We report the development of a suitable protocol for the identification of the biological origin of binding media on tiny samples from ancient paintings, by exploitation of the high specificity and high sensitivity offered by the state-of-the art DNA analysis. In particular, our aim was to molecularly characterize mitochondrial regions of the animal species traditionally employed for obtaining glues. The model has been developed using aged painting models and then tested to analyze the organic components in samples from the polychrome terracotta Madonna of Citerna by Donatello (1415-1420), where, by GC-MS and FTIR spectroscopy, animal glues and siccative oils were identified. The results obtained are good in terms of both sensibility and specificity of the method. First of all, it was possible to confirm that Donatello used animal glue for the preparation of the painted layers of the Madonna of Citerna and, specifically, glue derived from Bos taurus. Data obtained from sequencing confirm that each sample contains animal glue, revealing that it was mostly prepared from two common European taurine lineages called T2 and T3. There is one remarkable exception represented by one sample which falls into a surviving lineage of the now extinct European aurochs.     

A novel base-mediated intramolecular hydroamination to build fused heteroaryl pyrazinones

Functionalized fused heteroaryl pyrazinones were built up through a novel DBU-catalyzed intramolecular hydroamination reaction of aryl(prop-2-yn-1-yl)-1H-heteroaryl-2-carboxamides. The nucleophilic addition afforded three isomers; two with an exo-cyclic double bond [cis (Z), trans (E)], and a third one with an endo-cyclic double bond. After the carboxamide deprotection, isomerization of the mixture under acidic conditions resulted in a unique isomer.     

Full rank interpolatory subdivision: A first encounter with the multivariate realm

We extend our previous work on interpolatory vector subdivision schemes to the multivariate case. As in the univariate case we show that the diagonal and off-diagonal elements of such a scheme have a significantly different structure and that under certain circumstances symmetry of the mask can increase the polynomial reproduction power of the subdivision scheme. Moreover, we briefly point out how tensor product constructions for vector subdivision schemes can be obtained.     

LEED,AES and thermal desorption studies of chemisorbed Hydrogen and hydrocarbons (C2H2, C2H4, C6H6, C6H12) on the (111) and stepped [6(111) × (100)] iridium crystal surfaces; comparison with platinum

The adsorption of hydrogen, ethylene, acetylene, cyclohexane and benzene was studied on both the (111) and stepped [6(111) × (100)] crystal surfaces of iridium. The techniques used were low energy electron diffraction, Auger electron spectroscopy, and thermal desorption mass spectrometry. At 30°C, acetylene, ethylene and benzene are adsorbed with a sticking probability near unity. The sticking probability of cyclohexane is less than 0.1 on both surfaces. Heating the (111) surface above 800°C, in the presence of the hydrocarbons, results in the formation of an ordered carbonaceous overlayer with a diffraction pattern corresponding to a (9 × 9) surface structure. No indication for ordering of the carbonaceous residue was found on the stepped iridium surface in these experimental conditions. The hydrocarbon molecules form only poorly ordered surface structures on both iridium surfaces when the adsorption is carried out at 30°C. Benzene is the only gas that can be desorbed from the surfaces in large amounts by heating. Ethylene remains largely on the surface, only a few percent is removed by heating while acetylene and cyclohexane cannot be desorbed at all. When adsorption is carried out at 30°C and the crystal is subsequently flashed to high temperature, hydrogen is liberated from the surface. The hydrogen desorption spectra from the iridium surfaces exposed to C₂H₄, C₂H₂, or C₆H₆ exhibit two hydrogen desorption peaks, one around 200°C and the second around 350°C. The temperatures where these peaks appear vary slightly with the type of hydrocarbon. The relative intensities of these two peaks depend strongly on the surface used. Arguments are presented that decomposition of the hydrocarbon molecules (C-H bond breaking nd possibly also C-C bond breaking) occurs easier on the stepped iridium surface than on the (111) surface. Hydrogen is desorbed at a higher temperature from an iridium surface possessing a high density of surface imperfections than from a perfect iridium (111) surface. The results are compared with those obtained previously on similar crystal surfaces of platinum. It appears that C-H bond breaking occurs more easily on iridium than on platinum.     

Evidence for Degradation of the Chrome Yellows in Van Gogh’s Sunflowers: A Study Using Noninvasive In Situ Methods and Synchrotron‐Radiation‐Based X‐ray Techniques

This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh’s Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron‐radiation‐based X‐ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO₄ and the sulfur‐rich PbCr_1?xS_xO₄ (x≈0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., Cr^III compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future.     

Hybrid Multivalent Jack Bean α-Mannosidase Inhibitors: The First Example of Gold Nanoparticles Decorated with Deoxynojirimycin Inhitopes

Among carbohydrate-processing enzymes, Jack bean α-mannosidase (JBα-man) is the glycosidase with the best responsiveness to the multivalent presentation of iminosugar inhitopes. We report, in this work, the preparation of water dispersible gold nanoparticles simultaneously coated with the iminosugar deoxynojirimycin (DNJ) inhitope and simple monosaccharides (β-d-gluco- or α-d-mannosides). The display of DNJ at the gold surface has been modulated (i) by using an amphiphilic linker longer than the aliphatic chain used for the monosaccharides and (ii) by presenting the inhitope, not only in monomeric form, but also in a trimeric fashion through combination of a dendron approach with glyconanotechnology. The latter strategy resulted in a strong enhancement of the inhibitory activity towards JBα-man, with a K_i in the nanomolar range (K_i = 84 nM), i.e., more than three orders of magnitude higher than the monovalent reference compound.