966 resultados para Gesualdo, Carlo, príncipe di Venosa, ca.1560-1613
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Collection includes promotional material such as posters and pamphlets, surveys conducted by the BJE, and press releases. Also includes numerous publications, the majority being bulletins, newsletters, educational material, and bibliographies.
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Genetics, the science of heredity and variation in living organisms, has a central role in medicine, in breeding crops and livestock, and in studying fundamental topics of biological sciences such as evolution and cell functioning. Currently the field of genetics is under a rapid development because of the recent advances in technologies by which molecular data can be obtained from living organisms. In order that most information from such data can be extracted, the analyses need to be carried out using statistical models that are tailored to take account of the particular genetic processes. In this thesis we formulate and analyze Bayesian models for genetic marker data of contemporary individuals. The major focus is on the modeling of the unobserved recent ancestry of the sampled individuals (say, for tens of generations or so), which is carried out by using explicit probabilistic reconstructions of the pedigree structures accompanied by the gene flows at the marker loci. For such a recent history, the recombination process is the major genetic force that shapes the genomes of the individuals, and it is included in the model by assuming that the recombination fractions between the adjacent markers are known. The posterior distribution of the unobserved history of the individuals is studied conditionally on the observed marker data by using a Markov chain Monte Carlo algorithm (MCMC). The example analyses consider estimation of the population structure, relatedness structure (both at the level of whole genomes as well as at each marker separately), and haplotype configurations. For situations where the pedigree structure is partially known, an algorithm to create an initial state for the MCMC algorithm is given. Furthermore, the thesis includes an extension of the model for the recent genetic history to situations where also a quantitative phenotype has been measured from the contemporary individuals. In that case the goal is to identify positions on the genome that affect the observed phenotypic values. This task is carried out within the Bayesian framework, where the number and the relative effects of the quantitative trait loci are treated as random variables whose posterior distribution is studied conditionally on the observed genetic and phenotypic data. In addition, the thesis contains an extension of a widely-used haplotyping method, the PHASE algorithm, to settings where genetic material from several individuals has been pooled together, and the allele frequencies of each pool are determined in a single genotyping.
Spray deposition of exfoliated MoS2 flakes as hole transport layer in perovskite-based photovoltaics
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We propose the use of solution-processed molybdenum disulfide (MoS2) flakes as hole transport layer (HTL) for metal-organic perovskite solar cells. MoS2 bulk crystals are exfoliated in 2-propanol and deposited on perovskite layers by spray coating. We fabricated cells with glass/FTO/compact-TiO2/mesoporous-TiO2/CH3NH3PbI3/spiro- OMeTAD/Au structure and cells with the same structure but with MoS2 flakes as HTL instead of spiro-OMeTAD, the most widely used HTL. The electrical characterization of the cells with MoS2 as HTL show promising power conversion efficiency -η- of 3.9% with respect to cells with pristine spiro-OMeTAD (η=3.1%). Endurance test on 800-hour shelf life has shown higher stability for the MoS2–based cells (ΔPCE/PCE=-17%) with respect to the doped spiro-OMeTAD-based one (ΔPCE/PCE =-45%). Further improvements are expected with the optimization of the MoS2 deposition process
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A Monte Carlo simulation of Ising chains with competing short-range and infiniterange interactions has been carried out. Results show that whenever the system does not enter a metastable state, variation of temperature brings about phase transitions in the Ising chain. These phase transitions, except for two sets of interaction strengths, are generally of higher order and involve changes in the long-range order while the short-range order remains unaffected.
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We have shown previously that the Ca2+-specific fluorescent dyes chlortetracycline (CTC) and indo-1/AM can be used to distinguish between prestalk and prespore cells in Dictyostelium discoideum at a very early stage. In the present study, pre- and post-aggregative amoebae of Dictyostelium discoideum were labelled with CTC or indo-1 and their fluorescence monitored after being drawn into a fine glass capillary. The cells rapidly form two zones of Ca2+-CTC or Ca2+-indo-1 fluorescence. Anterior (air side) cells display a high level of fluorescence; the level drops in the middle portion of the capillary and rises again to a lesser extent in the posteriormost cells (oil side). When bounded by air on both sides, the cells display high fluorescence at both ends. When oil is present at both ends of the capillary, there is little fluorescence except for small regions at the ends. These outcomes are evident within a couple of minutes of the start of the experiment and the fluorescence pattern intensifies over the course of time. By using the indicator neutral red, as well as with CTC and indo-1, we show that a band displaying strong fluorescence moves away from the anterior end before stabilizing at the anterior-posterior boundary. We discuss our findings in relation to the role of Ca2+ in cell-type differentiation in Dictyostelium discoideum.
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A survey of the literature on lanthanide coordination compounds reveals that ligands involving ether oxygens as donor atoms have received very little attention [ 11. Only recently have the complexes of lanthanides with cyclic polyethers been characterized [l-3]. We report in this communication that interaction of rareearth perchlorates with two new ligands namely N,N,N’,N’-tetramethyl-u-carboxamido-Oanisamide (TMCA) and N,N’-di-t-butyl-crcarboxamido- 0-anisamide (DTBCA). The two ligands are potentially tridentate possessing two amide moieties and an ether linkage in between. The isolated complexes have been characterized by analysis, electrolytic conductance, infrared and electronic spectra. The ‘H and “C NMR spectra for the diamagnetic La3+ and Y3+ complexes are also discussed.
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The 270 MHz 1H n.m.r. spectrum of benzyloxycarbonyl-Pro-N-methylamide in CDCl3 is exchange broadened at 293° K. Spectral lines due to two species are frozen out at 253° K and a dynamically averaged spectrum is obtained at 323° K. A selective broadening of the Cβ and Cγ resonances in the 13C n.m.r. spectrum is observed at 253° K, with a splitting of the Cβ and Cγ resonances into a pair of lines of unequal intensity. A similar broadening of Cβ and Cγ peaks is also detected in pivaloyl-Pro-N-methylamide where cis-trans interconversion about the imide bond is precluded by the bulky t-butyl group. The rate process is thus attributed to rotation about the Cα-CO bond (ψ) and a barrier (ΔG#) of 14kcal mol-1 is estimated. 13C n.m.r. data for pivaloyl-Pro-N-methylamide in a number of solvents is presented and the differences in the Cβ and Cγ chemical shifts are interpreted in terms of rotational isomerism about the Cα-CO bond.
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The crystal structures of two oligopeptides containing di-n-propylglycine (Dpg) residues, Boc-Gly-Dpg-Gly-Leu-OMe (1) and Boc-Val-Ala-Leu-Dpg-Val-Ala-Leu-Val-Ala-Leu-Dpg-Val-Ala-Leu-OMe (2) are presented. Peptide 1 adopts a type I-turn conformation with Dpg(2)-Gly(3) at the corner positions. The 14-residue peptide 2 crystallizes with two molecules in the asymmetric unit, both of which adopt -helical conformations stabilized by 11 successive 5 1 hydrogen bonds. In addition, a single 4 1 hydrogen bond is also observed at the N-terminus. All five Dpg residues adopt backbone torsion angles (, ) in the helical region of conformational space. Evaluation of the available structural data on Dpg peptides confirm the correlation between backbone bond angle NCC() and the observed backbone , values. For > 106° , helices are observed, while fully extended structures are characterized by < 106° . The mean values for extended and folded conformations for the Dpg residue are 103.6° ± 1.7° and 109.9° ± 2.6° , respectively.
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Phase relations in the system Ca-Ti-O have been established by equilibration of several samples at 1200 K for prolonged periods and identification of phases in quenched samples by optical and scanning electron microscopy, XRD and EDS. Samples representing 20 compositions in the ternary system were analyzed. There was negligible solid solubility of Ca in the phases along the binary Ti-O, and of Ti in CaO. Four ternary oxides were identified: CaTiO3, Ca4Ti3O10 and Ca3Ti2O7 containing tetravalent titanium, and CaTi2O4 containing trivalent titanium. Tie-lines link calcium titanite (CaTi2O4) with the three calcium titanates (CaTiO3, Ca4Ti3O10 and Ca3Ti2O7), CaO, oxygen excess TiO1+delta and stoichiometric TiO. Tie-lines connect CaTiO3 with TiO2-x, Magneli phases TinO2n-1 (28 >= n >= 4), Ti3O5, Ti2O3 and TiO1+delta. CaO was found to coexist with TiO, and Ti-O solid solutions alpha and beta. The phase diagram is useful for understanding the mechanisms and kinetics of direct calciothermic reduction of TiO2 to metal and electrochemical reduction of TiO2 using graphite anode and molten CaCl2 electrolyte.
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A better understanding of the limiting step in a first order phase transition, the nucleation process, is of major importance to a variety of scientific fields ranging from atmospheric sciences to nanotechnology and even to cosmology. This is due to the fact that in most phase transitions the new phase is separated from the mother phase by a free energy barrier. This barrier is crossed in a process called nucleation. Nowadays it is considered that a significant fraction of all atmospheric particles is produced by vapor-to liquid nucleation. In atmospheric sciences, as well as in other scientific fields, the theoretical treatment of nucleation is mostly based on a theory known as the Classical Nucleation Theory. However, the Classical Nucleation Theory is known to have only a limited success in predicting the rate at which vapor-to-liquid nucleation takes place at given conditions. This thesis studies the unary homogeneous vapor-to-liquid nucleation from a statistical mechanics viewpoint. We apply Monte Carlo simulations of molecular clusters to calculate the free energy barrier separating the vapor and liquid phases and compare our results against the laboratory measurements and Classical Nucleation Theory predictions. According to our results, the work of adding a monomer to a cluster in equilibrium vapour is accurately described by the liquid drop model applied by the Classical Nucleation Theory, once the clusters are larger than some threshold size. The threshold cluster sizes contain only a few or some tens of molecules depending on the interaction potential and temperature. However, the error made in modeling the smallest of clusters as liquid drops results in an erroneous absolute value for the cluster work of formation throughout the size range, as predicted by the McGraw-Laaksonen scaling law. By calculating correction factors to Classical Nucleation Theory predictions for the nucleation barriers of argon and water, we show that the corrected predictions produce nucleation rates that are in good comparison with experiments. For the smallest clusters, the deviation between the simulation results and the liquid drop values are accurately modelled by the low order virial coefficients at modest temperatures and vapour densities, or in other words, in the validity range of the non-interacting cluster theory by Frenkel, Band and Bilj. Our results do not indicate a need for a size dependent replacement free energy correction. The results also indicate that Classical Nucleation Theory predicts the size of the critical cluster correctly. We also presents a new method for the calculation of the equilibrium vapour density, surface tension size dependence and planar surface tension directly from cluster simulations. We also show how the size dependence of the cluster surface tension in equimolar surface is a function of virial coefficients, a result confirmed by our cluster simulations.
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Purpose: Mutations in IDH3B, an enzyme participating in the Krebs cycle, have recently been found to cause autosomal recessive retinitis pigmentosa (arRP). The MDH1 gene maps within the RP28 arRP linkage interval and encodes cytoplasmic malate dehydrogenase, an enzyme functionally related to IDH3B. As a proof of concept for candidate gene screening to be routinely performed by ultra high throughput sequencing (UHTs), we analyzed MDH1 in a patient from each of the two families described so far to show linkage between arRP and RP28. Methods: With genomic long-range PCR, we amplified all introns and exons of the MDH1 gene (23.4 kb). PCR products were then sequenced by short-read UHTs with no further processing. Computer-based mapping of the reads and mutation detection were performed by three independent software packages. Results: Despite the intrinsic complexity of human genome sequences, reads were easily mapped and analyzed, and all algorithms used provided the same results. The two patients were homozygous for all DNA variants identified in the region, which confirms previous linkage and homozygosity mapping results, but had different haplotypes, indicating genetic or allelic heterogeneity. None of the DNA changes detected could be associated with the disease. Conclusions: The MDH1 gene is not the cause of RP28-linked arRP. Our experimental strategy shows that long-range genomic PCR followed by UHTs provides an excellent system to perform a thorough screening of candidate genes for hereditary retinal degeneration.
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We describe an investigation of (Ba3MMWO9)-M-II-W-IV oxides for M-II = Ca, Zn, and other divalent metals and M-IV = Ti, Zr. In general, a 1:2-ordered 6H (hexagonal, P6(3)/mmc) perovskite structure is stabilized at high temperatures (1300 degrees C) for all of the (Ba3MTiWO9)-Ti-II oxides investigated. An intermediate phase possessing a partially ordered 1:1 double perovskite (3C) structure with the cation distribution, Ba-2(Zn2/3Ti1/3)(W2/3Ti1/3)O-6, is obtained at 1200 degrees C for Ba3ZnTiWO9. Sr substitution for Ba in the latter stabilizes the cubic 3C structure instead of the 6H structure. A metastable Ba3CaZrWO9 that adopts the 3C (cubic, Fm (3) over barm) structure has also been synthesized by a low-temperature metathesis route. Besides yielding several new perovskite oxides that may be useful as dielectric ceramics, the present investigation provides new insights into the complex interplay of crystal chemistry (tolerance factor) and chemical bonding (anion polarization and d(0)-induced distortion of metal-oxygen octahedra) in the stabilization of 6H versus 3C perovskite structures for the (Ba3MMWO9)-M-II-W-IV series.