3,705 research outputs found

    Organic Carbon Burial following the Middle Eocene Climatic Optimum (MECO) in the central - western Tethys

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    We present trace metal geochemistry and stable isotope records for the middle Eocene Alano di Piave section, NE Italy, deposited during magnetochron C18n in the marginal Tethys Ocean. We identify a \sim 500 kyr long carbon isotope perturbation event we infer to be the middle Eocene Climatic Optimum (MECO) confirming the northern hemisphere expression and global occurrence of MECO. Interpreted peak climatic conditions are followed by the rapid deposition of two organic rich intervals (\le3\% TOC) and contemporaneous positive δ13\delta^{13}C excursions. These two intervals are associated with increases in the concentration of sulphur and redox-sensitive trace metals, and low concentrations of Mn, as well as coupled with the occurrence of pyrite. Together these changes imply low, possibly dysoxic, bottom water O2_{2} conditions promoting increased organic carbon burial. We hypothesize that this rapid burial of organic carbon lowered global {\it p}CO2_{2} following the peak warming and returned the climate system to the general Eocene cooling trend

    Craniofacial superimposition studies on a set of cosimo i de’ medici’s (1519-1574) and eleonora di toledo’s (1522-1562) portraits

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    A set of portraits of the Florentine grand duke Cosimo I de’ Medici (1519-1574) and of his wife Eleonora di Toledo (1522–1562) painted by two major representatives of Florentine Mannerism (Italian Late Renaissance), Pontormo and Bronzino was compared with the skulls of the two subjects utilizing the forensic technique of craniofacial superimposition. The results show that, in the case of Cosimo I, both a painting (Pontormo, workshop of, Cosimo I de’ Medici, 1537) and a drawing (Pontormo, Cosimo I de’ Medici in Profile, 1537) show lack of fit with the skull in four points (the glabellar outline, the depth of the nasal bridge, the bony lateral wall of the orbit, and the outline of the frontal process of the zygomatic bone). The drawing, therefore, seems to contradict the well established idea that Renaissance painters prepared lifelike sketches of their sitters which were then modified when transferred to the painting. In the case of Eleonora di Toledo, on the other hand, craniofacial superimposition analysis reveals that Bronzino, possibly as the result of a desperate search for the “best angle” of the sitter, adopted an unusual perspective to portray the duchess (Bronzino, Eleonora di Toledo, c. 1539) possibly looking down the sitter, by standing, while the sitter was seated in front of him. The face of the sitter was subsequently, in another painting (Bronzino, Eleonora di Toledo and Her Son Giovanni, c. 1544-45) “transplanted” onto the rest of the body given the impression that the duchess “looks” at the viewer from above. © 2016 Romanian Society of Legal Medicine

    Keeping it modern, making it sustainable. Monitoring and energy retrofitting the Urbino University Colleges

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    This paper presents a research to balance building conservation, users’ comfort and energy efficiency of a masterpiece of XX century architecture. The Urbino University Colleges were designed by architect Giancarlo de Carlo and built since 1962 to 1983 beside the Renaissance city. They host more than 1,000 students within 5 dormitories and 62,000 m2 surface. Authors discuss some outcomes from the “Keeping it modern” research program financed by the Getty Foundation in 2016, which aims at providing the Colleges with a sustainable conservation plan. The goal is to lower heating and operational costs to allow funds in conservation activities. Specific issues regard: the striking dimensions of the complex, the constructive features (brickwork walls, exposed concrete structures, single-glazed windows) and the lack of data about the hygrothermal performances. The research thus includes a hygrothermal analysis, a proposal for the energy retrofitting, a building-HVAC model, a test on a pilot site. Authors have monitored surface temperatures, indoor air temperature and humidity for one year, even mapping their distribution through a digital psychrometer. Thermal imaging has been used to detect heat losses, thermal bridges and heat gains due to the solar radiation. Data have fed a building-HVAC model, which was a reference to design an appropriate strategy for retrofitting and improving the energy efficiency of the complex. Some solutions are being implemented on a pilot site. The building performances before and after retrofitting are compared. Results provide indications to merge conservation and sustainability of a XX century heritage building. In conclusion, the solid knowledge of each case confirms being required to support a retrofit proposal of a heritage building, moreover in case of a XX century building, as the cultural value of such a huge heritage is often disregarded to improve its energy performance

    On Symmetries of Extremal Black Holes with One and Two Centers

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    After a brief introduction to the Attractor Mechanism, we review the appearance of groups of type E7 as generalized electric-magnetic duality symmetries in locally supersymmetric theories of gravity, with particular emphasis on the symplectic structure of fluxes in the background of extremal black hole solutions, with one or two centers. In the latter case, the role of an "horizontal" symmetry SL(2,R) is elucidated by presenting a set of two-centered relations governing the structure of two-centered invariant polynomials.Comment: 1+13 pages, 2 Tables. Based on Lectures given by SF and AM at the School "Black Objects in Supergravity" (BOSS 2011), INFN - LNF, Rome, Italy, May 9-13 201

    Gut Microbiome of an 11th Century A.D. Pre-Columbian Andean Mummy

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    The process of natural mummification is a rare and unique process from which little is known about the resulting microbial community structure. In the present study, we characterized the microbiome of paleofeces, and ascending, transverse and descending colon of an 11th century A.D. pre-Columbian Andean mummy by 16S rRNA gene high-throughput sequencing and metagenomics. Firmicutes were the most abundant bacterial group, with Clostridium spp. comprising up to 96.2% of the mummified gut, while Turicibacter spp. represented 89.2% of the bacteria identified in the paleofeces. Microbiome profile of the paleofeces was unique when compared to previously characterized coprolites that did not undergo natural mummification. We identified DNA sequences homologous to Clostridium botulinum, Trypanosoma cruzi and human papillomaviruses (HPVs). Unexpectedly, putative antibiotic-resistance genes including beta-lactamases, penicillin-binding proteins, resistance to fosfomycin, chloramphenicol, aminoglycosides, macrolides, sulfa, quinolones, tetracycline and vancomycin, and multi-drug transporters, were also identified. The presence of putative antibiotic-resistance genes suggests that resistance may not necessarily be associated with a selective pressure of antibiotics or contact with European cultures. Identification of pathogens and antibiotic-resistance genes in ancient human specimens will aid in the understanding of the evolution of pathogens as a way to treat and prevent diseases caused by bacteria, microbial eukaryotes and viruses

    Can be gravitational waves markers for an extra-dimension?

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    The main issue of the present letter is to fix specific features (which turn out being independent of extradimension size) of gravitational waves generated before a dimensional compactification process. Valuable is the possibility to detect our prediction from gravitational wave experiment without high energy laboratory investigation. In particular we show how gravitational waves can bring information on the number of Universe dimensions. Within the framework of Kaluza-Klein hypotheses, a different morphology arises between waves generated before than the compactification process settled down and ordinary 4-dimensional waves. In the former case the scalar and tensor degrees of freedom can not be resolved. As a consequence if were detected gravitational waves having the feature here predicted (anomalous polarization amplitudes), then they would be reliable markers for the existence of an extra dimension.Comment: 5 pages, two figure, to appear on Int. Journ. Mod. Phys.

    Matrix Norms, BPS Bounds and Marginal Stability in N=8 Supergravity

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    We study the conditions of marginal stability for two-center extremal black holes in N-extended supergravity in four dimensions, with particular emphasis on the N=8 case. This is achieved by exploiting triangle inequalities satisfied by matrix norms. Using different norms and relative bounds among them, we establish the existence of marginal stability and split attractor flows both for BPS and some non-BPS solutions. Our results are in agreement with previous analysis based on explicit construction of multi-center solutions.Comment: 1+15 pages; v2: some new formulas added and misprints corrected; v3: typos fixed, various refinements, Sec. 2.4 rewritten; to appear on JHE

    Indexed left atrial volume, C-reactive protein and erythrocyte sedimentation rate as predictors of recurrence of non-valvular atrial fibrillation after successful cardioversion

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    Indexed left atrial volume, C-reactive protein and erythrocyte sedimentation rate as predictors of recurrence of non-valvular atrial fibrillation after successful cardioversio

    Exact expression for the diffusion propagator in a family of time-dependent anharmonic potentials

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    We have obtained the exact expression of the diffusion propagator in the time-dependent anharmonic potential V(x,t)=1/2a(t)x2+blnxV(x,t)={1/2}a(t)x^2+b\ln x. The underlying Euclidean metric of the problem allows us to obtain analytical solutions for a whole family of the elastic parameter a(t), exploiting the relation between the path integral representation of the short time propagator and the modified Bessel functions. We have also analyzed the conditions for the appearance of a non-zero flow of particles through the infinite barrier located at the origin (b<0).Comment: RevTex, 19 pgs. Accepted in Physical Review

    Ion diffusion modelling of Fricke-agarose dosemeter gels

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    In Fricke-agarose gels, an accurate determination of the spatial dose distribution is hindered by the diffusion of ferric ions. In this work, a model was developed to describe the diffusion process within gel samples of finite length and, thus, permit the reconstruction of the initial spatial distribution of the ferric ions. The temporal evolution of the ion concentration as a function of the initial concentration is derived by solving Fick's second law of diffusion in two dimensions with boundary reflections. The model was applied to magnetic resonance imaging data acquired at high spatial resolution (0.3 mm) and was found to describe accurately the observed diffusion effect
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