Early-Middle Pleistocene benthic turnover and oxygen isotope stratigraphy from the Central Mediterranean (Valle di Manche, Crotone Basin, Italy): data and trends

Ostracod faunal turnover and oxygen isotope data (foraminifera) along the Valle di Manche (VdM) section are herein compiled. Specifically, the material reported in this work includes quantitative palaeoecological data and patterns of ostracod fauna framed within a high-resolution oxygen isotope stratigraphy (δ18O) from Uvigerina peregrina. In addition, the multivariate ostracod faunal stratigraphic trend (nMDS axis-1 sample score) is calibrated using bathymetric distributions of extant molluscs sampled from the same stratigraphic intervals along the VdM section. Data and analyses support the research article “Dynamics of benthic marine communities across the Early-Middle Pleistocene boundary in the Mediterranean region (Valle di Manche, Southern Italy): biotic and stratigraphic implications” Rossi et al. [1]

A single-point mutation in FGFR2 affects cell cycle and Tgfβ signalling in osteoblasts

AbstractFgf and Tgfβ are key regulators of bone development. It is not known, however, whether there is a relationship between defective Fgf signalling, resulting in a premature cranial suture fusion, and Tgfβ signalling. We used mouse calvaria osteoblasts carrying a mutation (hFGFR2-C278F) associated with Crouzon and Pfeiffer syndromes to investigate effects of this mutation on cell growth and possible mechanisms underlying it. Mutated osteoblasts displayed reduced S-phase, increased apoptosis and increased differentiation. As Tgfβ signalling appeared to be required in an autocrine/paracrine manner for osteoblast proliferation, we tested the hypothesis that reduced growth might be due, at least in part, to an altered balance between FGF and Tgfβ signalling. Tgfβ expression was indeed decreased in mutated osteoblasts, as compared to osteoblasts carrying the wild type hFGFR2. Treatment with Tgfβ, however, neither increased proliferation in mutated osteoblasts, unlike in controls, nor rescued proliferation in control osteoblasts treated with an Erk1/2 inhibitor. Significantly, Erk2, that is important for proliferation, was reduced relatively to Erk1 in mutated cells. Altogether this study suggests that the hFGFR2-C278F mutation affects the osteoblast ability to respond to Tgfβ stimulation via the Erk pathway and that the overall effect of the mutation is a loss of function

EVALUATION OF CRACK WIDTH IN RC TIES THROUGH A NUMERICAL "RANGE" MODEL

The problem of cracking in reinforced concrete (RC) tensile members has been studied extensively in the past, not only for the analysis of tension zones, but also for understanding and modeling the behavior of beams in bending. Despite the large number of published studies, there is still no agreement on the relative importance of the most critical parameters influencing crack width and spacing (especially bond-slip and stress diffusion in concrete cover), as proved by the development of more than twenty different formulae available in technical literature [1]. Aim of this work is to investigate if a model based exclusively on bond-slip is able to predict correctly crack width and spacing or if the contribution of stress diffusion in concrete cover - which is included in several design Codes and in some numerical or analytical approaches – must be considered. To this purpose, a one-dimensional numerical model based on bond between steel and concrete is here developed for analyzing the behavior of RC tension ties, by also taking into account the influence of bond deterioration near crack surfaces. To consider the uncertainty of crack pattern evolution, the model provides a range of crack widths and spacing that, according to bond theory, are possible for a given load. The effectiveness of the proposed procedure is verified through comparisons with significant experimental results on RC tension members available in the technical literature [2-3], both in terms of global behavior and in terms of crack width and crack spacing evolution as loading increases. These comparisons prove that bond deterioration improves the results and that the proposed approach can be successfully adopted for design purposes, since it provides a correct estimate of maximum crack width. The obtained results are also compared with Codes provisions and the effectiveness of different approaches for predicting crack width is analyzed and discussed. References [1] Borosnyoi A, Balazs GL. Models for flexural cracking in concrete: the state of the art. Struct Concr, 2005; 6(2): 53-62. [2] Wu HQ, Gilbert RI. An experimental study of tension stiffening in reinforced concrete members under short-term and long-term loads. In: UNICIV Report No. R-449, 2008, The University of New South Wales, Sidney, Australia. [3] Gijsbers FBJ, Hehemann AA. Enige trekproven op gewapend beton (Some tensile tests on reinforced concrete). In: Report BI-77-61, 1977, TNO Inst for Building Mat and Struct, Delft, The Netherlands

The production of metal artefacts in Southern Etruria (Central Italy): case studies from copper to Iron Age

An analytical study is presented, aimed to determine the elemental composition of copper-based artefacts dated back from Copper Age to Early Iron Age (mid-fourth millennium to the VIIIth century B.C.), found on the Tyrrhenian side of the peninsula, corresponding to the Lazio region. The objects belong to different archaeological contexts and had various functions. They were analysed by the X-ray fluorescence technique. The results highlight the experimental character of Copper Age metallurgy, which will later evolve in the established use of copper-tin alloys. Regarding the Bronze Age, despite the typological and functional heterogeneity of the artefacts and the wide chronological range, the alloys are relatively homogeneous in composition, with regular changes that appear related to chronology, according to what is already known for the Italian peninsula. Such changes are supposedly due to variations in the availability of tin, which was not locally mined. Early Iron Age metallurgy is represented by the Selvicciola Hoard solely, which restricts the possibility of generalizing the conclusions. A striking feature of the alloys is the great compositional difference between the complete and the fragmented artefacts. The formers are made of tin bronze, whereas in the latter tin is replaced by antimony and/or lead. The use of such unusual alloys is unlikely due to lack of metallurgical knowledge. Considering the urbanized communities that arose in the Middle-Tyrrhenian area during the Early Iron Age, we suppose that such variability in a single context might be related to a production system capable of using alloys of different quality and value to satisfy a diversified demand

The Marine Isotope Stage 19 in the mid-latitude North Atlantic Ocean: astronomical signature and intra-interglacial variability

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Southwest Pacific deep-water carbonate chemistry during the Mid-Pleistocene Transition

After more than 40 years of research, there is still wide disagreement in defining when the Mid-Pleistocene Transition (MPT) occurred, with climate reconstructions ranging from an abrupt versus gradual transition that began as early as 1500 ka and ended as late as 600 ka. Our recent work in the Southwest Pacific (Ocean Drilling Program Site 1123) has provided some evidence for a rapid transition, suggesting that the MPT was initiated by an abrupt increase in global ice volume 900 thousand years ago [1]. This study uses shallow-infaunal benthic foraminifera Uvigerina spp. to disentangle the contributions of deep-water temperature (using Mg/Ca ratios) and ice volume to the oxygen isotopic composition of foraminiferal calcite over the last 1.5 Ma. The resulting sea-level reconstruction across the MPT shows that the critical step in ice-volume variation was associated with the suppression of melting in Marine Isotope Stage (MIS) 23, followed by renewed ice growth in MIS 22 to yield a very large ice sheet with 120 m of sea level lowering. Here, we built on this work with the aim to investigate further the abrupt event centered on MIS 24 to 22 (the ‘900-ka event’) and try to shed some light on the processes and mechanisms that caused the MPT. Different hypotheses account for the origin of the MPT as a response to long-term ocean cooling, perhaps because of lowering CO2. To better quantify the role of the carbon system during the MPT, we reconstruct past changes in bottom water inorganic carbon chemistry from the trace element (B/Ca) and stable isotopic composition of calcite shells of the infaunal benthic foraminifera Uvigerina spp. from 1100 ka to 350 ka at ODP Site 1123. This site was retrieved from Chatham Rise, east of New Zealand in the Southwest Pacific Ocean (41º47.2’S, 171º 29.9’ W, 3290 m water depth) and lies under the Deep Western Boundary Current (DWBC) that flows into the Pacific Ocean, and is responsible for most of the deep water in that ocean; DWBC strength is directly related to processes occurring around Antarctica. The ratio of boron to calcium (B/Ca) in benthic foraminifer shells has proven to be a reliable indicator of the calcite saturation state of ocean bottom waters. The comparison between benthic foraminifera δ18O and δ13C shows a similar trend at ODP Site 1123, implying a close relationship between these climate and carbon cycle signals, and we use our B/Ca record reconstructed from the same samples to explore the potential processes behind this tight coupling. These results permit preliminary discussion on the deep-water carbonate saturation state during glacial/interglacial cycles. Deep-water temperatures estimates using Mg/Ca and oxygen isotopic composition of seawater (δ18Osw) are available from Site 1123 for the last 1.5 million years [1] and the phase relationship between the different signals is tentatively assessed for the early/middle Pleistocene, when different patterns of climate variability have been inferred from marine and ice cores records. [1] Elderfield et al. (2012). Evolution of ocean temperature and ice volume through the Mid Pleistocene Climate Transition. Science, vol. 337, 6095, 704-70

Experimental characterization of fiber-reinforced cementitious mortar under tension

This work focuses on the mechanical characterization of the inorganic matrix used for Fiber-Reinforced Cementitious Matrix (FRCM) composites, nowadays widely used to retrofit existing reinforced concrete and masonry structures. While several works in technical literature investigate the experimental behavior of the whole FRCM composite, few information are available on the mechanical characterization of the mortar, which contains polymers and synthetic fibers in its admixture. However, the knowledge of its behavior in tension, especially after crack formation, is an important feature for the calibration of constitutive models to be adopted in the study of structural elements strengthened with FRCM. To this aim, an experimental program was performed on mortar specimens characterized by different shapes and dimensions, tested under direct tension or three-point-bending. From the performed tests, it was possible to characterize inorganic matrix behavior both in the uncracked stage, through the determination of the elastic parameters (elastic modulus and Poisson’s coefficient), and in the cracked stage. The use of digital image correlation (DIC) technique also allowed the study of the evolution of crack propagation in the specimens. Lastly, a correlation factor between axial and flexural tensile strength is proposed, for both design and numerical modelling purposes