Non-neuronal Cells Are Not The Limiting Factor For The Low Axonal Regeneration In C57bl/6j Mice.

Peripheral axonal regeneration was investigated in adult male mice of the C57BL/6J (C), BALB/cJ (B) and A/J (A) strains and in their F1 descendants using a predegenerated nerve transplantation model. Four types of transplants were performed: 1) isotransplants between animals of the C, B and A strains; 2) donors of the C strain and recipients of the C x B and C x A breeding; 3) donors of the B strain and recipients of the C x B breeding, and 4) donors of the A strain and recipients of the C x A breeding. Donors had the left sciatic nerve transected and two weeks later a segment of the distal stump was transplanted into the recipient. Four weeks after transplantation the regenerated nerves were used to determine the total number of regenerated myelinated fibers (TMF), diameter of myelinated fibers (FD) and myelin thickness (MT). The highest TMF values were obtained in the groups where C57BL/6J mice were the donors (C to F1 (C x B) = 4658 +/- 304; C to F1 (C x A) = 3899 +/- 198). Also, A/J grafts led to a significantly higher TMF (A to F1 (C x A) = 3933 +/- 565). Additionally, isotransplant experiments showed that when the nerve is previously degenerated, C57BL/6J mice display the largest number of myelinated fibers (C to C = 3136 +/- 287; B to B = 2759 +/- 170, and A to A = 2835 +/- 239). We also observed that when C57BL/6J was the graft donor, FD was the highest and MT did not differ significantly when compared with the other groups. These morphometric results reinforce the idea that Schwann cells and the nerve environment of C57BL/6J provide enough support to the regenerative process. In this respect, the present results support the hypothesis that the non-neuronal cells, mainly Schwann cells, present in the sciatic nerve of C57BL/6J mice are not the main limiting factor responsible for low axonal regeneration.331467-7

Large Eddy Simulations of a Low-Swirl Gaseous Partially Premixed Lifted Flame in Presence of Wall Heat Losses

The use of lifted flames presents some very promising advantages in terms of pollutant emissions and flame stability. The focus here is on a specific low-swirl injection system operated with methane and derived from an air-blast atomizer for aero-engine applications, which is responsible for flame lift-off. The key feature of this concept is the interaction between the swirling jet and the confinement walls, leading to a strong outer recirculation zone and thus to an upstream transport of combustion products from the main reaction region to the flame base. Here, the representation of the physics involved is challenging, since finite-rate effects govern the lift-off occurrence, and only a few numerical studies have been carried out on this test case so far. The aim of the present work is therefore to understand the limits of some state-of-the-art combustion models within the context of LES. Considering this context, two different strategies are adopted: the Flamelet-Generated Manifold (FGM) approach and the Thickened Flame (TF) model. A modified version of the FGM model including stretch and heat loss effects is also applied as an improvement of the standard model. Numerical results are compared with the available experimental data in terms of temperature and chemical species concentration maps, showing that the TF model can better reproduce the lift-off than the FGM approach

Effects of hydrodynamic cavitation, low-level thermal and low-level alkaline pre-treatments on sludge solubilisation.

Abstract WAS is a polluting and hazardous waste generated in WWTPs that must be treated to prevent pollution and human health risks. Anaerobic digestion is the most used process for sludge stabilization. However, it must be improved in terms of both speed and extend of degradation. With the purpose of reducing the energy and chemical consumption linked to sludge treatment, in this study, different anaerobic digestion pre-treatments such as low-level mechanical (hydrodynamic cavitation, 2 bar), low-level thermal (50 °C) and low-level alkaline (NaOH, KOH and Ca(OH)2, pH 10) methods, and a combination thereof, were tested as strategies to improve sludge solubilisation. When the pre-treatments were used alone, the alkaline pre-treatment showed the highest sludge solubilisation. Among the alkaline reagents tested, NaOH and KOH led to higher DDPCOD (41.6 and 39.4%), while only 8.4% was achieved by using Ca(OH)2. However, the low-level hydrodynamic cavitation assisted thermo-alkaline pre-treatment was the most efficient in terms of both sludge solubilisation (DDPCOD = 53.0%) and energy efficiency (EE = 64.5 mgΔSCOD kJ−1). The synergetic effects of the combined pre-treatment were also confirmed by the highest release of EPS. Furthermore, cytometric analyses showed that the main mechanism involved in sludge solubilisation for the investigated pre-treatments was flocs disintegration rather than cell lysis

High pressure melting of eclogite and metasomatism of garnet peridotites from Monte Duria Area (Central Alps, N Italy): A proxy for melt-rock reaction during subduction

In the Monte Duria area (Adula-Cima Lunga unit, Central Alps, N Italy) garnet peridotites occur in direct contact with migmatised orthogneiss (Mt. Duria) and eclogites (Borgo). Both eclogites and ultramafic rocks share a common high pressure (HP) peak at 2.8\u202fGPa and 750\u202f\ub0C and post-peak static equilibration at 0.8\u20131.0\u202fGPa and 850\u202f\ub0C. Garnet peridotites show abundant amphibole, dolomite, phlogopite and orthopyroxene after olivine, suggesting that they experienced metasomatism by crust-derived agents enriched in SiO2, K2O, CO2 and H2O. Peridotites also display LREE fractionation (La/Nd\u202f=\u202f2.4) related to LREE-rich amphibole and clinopyroxene grown in equilibrium with garnet, indicating that metasomatism occurred at HP conditions. At Borgo, retrogressed garnet peridotites show low strain domains characterised by garnet compositional layering, cut by a subsequent low-pressure (LP) chlorite foliation, in direct contact with migmatised eclogites. Kfs\u202f+\u202fPl\u202f+\u202fQz\u202f+\u202fCpx interstitial pocket aggregates and Cpx\u202f+\u202fKfs thin films around symplectites after omphacite parallel to the Zo\u202f+\u202fOmp\u202f+\u202fGrt foliation in the eclogites suggest that they underwent partial melting at HP. The contact between garnet peridotites and eclogites is marked by a tremolitite layer. The same rock also occurs as layers within the peridotite lens, showing a boudinage parallel to the garnet layering of peridotites, flowing in the boudin necks. This clearly indicates that the tremolitite boudins formed when peridotites were in the garnet stability field. Tremolitites also show Phl\u202f+\u202fTc\u202f+\u202fChl\u202f+\u202fTr pseudomorphs after garnet, both crystallised in a static regime postdating the boudins formation, suggesting that they derive from a garnet-bearing precursor. Tremolitites have Mg#\u202f>\u202f0.90 and Al2O3\u202f=\u202f2.75\u202fwt% pointing to ultramafic compositions but also show enrichments in SiO2, CaO, and LREE suggesting that they formed after the reaction between the eclogite-derived melt and the garnet peridotite at HP. To test this hypothesis, we performed a thermodynamic modelling at fixed P\u202f=\u202f3\u202fGPa and T\u202f=\u202f750\u202f\ub0C to model the chemical interaction between the garnet peridotite and the eclogite-derived melt. Our results show that this interaction produces an Opx\u202f+\u202fCpx\u202f+\u202fGrt assemblage plus Amp\u202f+\u202fPhl, depending on the water activity in the melt, suggesting that tremolitites likely derive from a previous garnet websterite with amphibole and phlogopite. Both peridotites and tremolitites also show a selective enrichment in LILE recorded by amphiboles in the spinel stability field, indicating that a fluid-assisted metasomatic event occurred at LP conditions, leading to the formation of a chlorite foliation post-dating the garnet layering in peridotites, and the retrogression of Grt-websterites in tremolitites. The Monte Duria area is a unique terrane where we can observe syn-deformation eclogite-derived melt interacting with garnet peridotite at HP, proxy of subduction environments

Kernel Spectral Clustering and applications

In this chapter we review the main literature related to kernel spectral clustering (KSC), an approach to clustering cast within a kernel-based optimization setting. KSC represents a least-squares support vector machine based formulation of spectral clustering described by a weighted kernel PCA objective. Just as in the classifier case, the binary clustering model is expressed by a hyperplane in a high dimensional space induced by a kernel. In addition, the multi-way clustering can be obtained by combining a set of binary decision functions via an Error Correcting Output Codes (ECOC) encoding scheme. Because of its model-based nature, the KSC method encompasses three main steps: training, validation, testing. In the validation stage model selection is performed to obtain tuning parameters, like the number of clusters present in the data. This is a major advantage compared to classical spectral clustering where the determination of the clustering parameters is unclear and relies on heuristics. Once a KSC model is trained on a small subset of the entire data, it is able to generalize well to unseen test points. Beyond the basic formulation, sparse KSC algorithms based on the Incomplete Cholesky Decomposition (ICD) and $L_0$, $L_1, L_0 + L_1$, Group Lasso regularization are reviewed. In that respect, we show how it is possible to handle large scale data. Also, two possible ways to perform hierarchical clustering and a soft clustering method are presented. Finally, real-world applications such as image segmentation, power load time-series clustering, document clustering and big data learning are considered.Comment: chapter contribution to the book "Unsupervised Learning Algorithms

Tidal modulation of river-flood deposits: How low can you go?

Quantification of the interaction between river discharge and tides is vital to characterize fluvio-deltaic systems, to identify diagnostic elements of tidal signatures in the rock record, and to reconstruct paleogeographies. In modern systems, even microtides can significantly influence delta morphodynamics; yet, many fundamental processes, particularly in prodeltaic settings, remain elusive. Here, by combining a unique process-product data set acquired during a flood event of the Po River (Italy) with numerical modeling, we show that tidal signatures are recorded in the open-water prodelta zone of a microtidal system. Based on the analyses of box-cores collected before and after a flood off the main distributary channel, we interpreted storm beds, tide-modulated flood strata of alternating normal and inverse graded beds, and rapid bioturbation. Modeling of the river discharge indicates that, at the peak of the flood, the steepening of the water-surface profile forced by 0.15 m lowering of sea level during low tides generated an 8% increase in river flow velocity. The alternation of profile steepness and associated cyclicity in flow strength during consecutive tidal cycles controlled the sediment load of the plume and, consequently, led to the deposition of tidal-modulated strata. Formation of microtidal signals appears to be enhanced in fluvio-deltaic successions characterized by multiple distributaries and in basins where river floods are out of phase with storm-wave activity. Bioturbation of sediment, which can start during the waning stage of the flow, and erosion by storm waves hamper the preservation of tidal signals, unless rapid burial occurs. The recognition of tidal-modulated strata in river-dominated settings may facilitate the characterization of mudstone reservoirs and reconstruction of paleogeographic conditions during deposition

Early cretaceous plume–ridge interaction recorded in the band-e-zeyarat ophiolite (North Makran, Iran): New constraints from petrological, mineral chemistry, and geochronological data

The North Makran domain (southeast Iran) is part of the Makran accretionary wedge and consists of an imbricate stack of continental and Neo-Tethyan oceanic tectonic units. Among these, the Band-e-Zeyarat ophiolite consists of (from bottom to top): ultramafic cumulates, layered gabbros, isotropic gabbros, a sheeted dyke complex, and a volcanic sequence. Sheeted dykes and volcanic rocks are mainly represented by basalts and minor andesites and rhyolites showing either normal-type (N) or enriched-type (E) mid-ocean ridge basalt affinities (MORB). These conclusions are also supported by mineral chemistry data. In addition, E-MORBs can be subdivided in distinct subtypes based on slightly different but significant light rare earth elements, Th, Nb, TiO2, and Ta contents. These chemical differences point out for different partial melting conditions of their mantle sources, in terms of source composition, partial melting degrees, and melting depths. U-Pb geochronological data on zircons from intrusive rocks gave ages ranging from 122 to 129 Ma. We suggest that the Band-e-Zeyarat ophiolite represents an Early Cretaceous chemical composite oceanic crust formed in a mid-ocean ridge setting by partial melting of a depleted suboceanic mantle variably metasomatized by plume-type components. This ophiolite records, therefore, an Early Cretaceous plume–ridge interaction in the Makran Neo-Tethys

Water Masses Variability in Inner Kongsfjorden (Svalbard) During 2010–2020

Kongsfjorden is an Arctic fjord located in the Svalbard archipelago. Its hydrography is influenced by the warm and saline Atlantic Water (AW) in the West Spitsbergen Current and the cold and fresh Polar Water circulating on the shelf. We assess the so-called atlantification of Kongsfjorden in the 2010–2020 decade by inspecting modifications in water properties and water masses variability through moored data and summer CTD surveys. Atlantification in this fjord has emerged as an increasing temperature and salinity, resulting from enhanced advection of Atlantic waters from the West Spitsbergen Current. The water column in inner Kongsfjorden warmed by 0.13°C/yr at 35 m and 0.06°C/yr at 85 m depth from 2010 to 2020, while salinity increased by 0.3 PSU. Depth-averaged temperatures have increased by 0.26°C/yr in the warmest months of the year, whereas they appear relatively stable in the coldest months. Both temperature and salinity present a linear regression change point in January 2017, with latter years featuring decreasing values. Highly diluted AW is found at the beginning of the decade, which give way to more and more pure AW in latter years, culminating in extensive intrusions in 2016 and 2017 determining the warmest and saltiest conditions over the decade in inner Kongsfjorden. Observations in the 2010–2020 decade confirm that Kongsfjorden has transitioned to an Atlantic-type fjord, featuring depleted sea ice conditions and rather regular shallow intrusions of AW in summer and frequently also in winter. Although single intrusions of AW are associated with dynamical events on the shelf, we found that the long-term temperature evolution in the inner Kongsfjord is consistent with the meridional temperature transport of the West Spitsbergen Current. The AW current flowing northward from lower latitudes along the western Svalbard archipelago thus has profoundly driven local conditions in the inner fjord in this decade

Garnets from Val d’Ala Rodingites, Piedmont, Italy: An Investigation of Their Gemological, Spectroscopic and Crystal Chemical Properties

In Val d\u2019Ala (Piedmont,Western Alps, Italy), the more interesting rocks for the mineralogical research are represented by rodingites (rich in mineralized veins and fractures) associated with serpentinites in the eclogitized oceanic crust of Piemonte Zone, south of Gran Paradiso Massif. Among the vein-filling minerals, garnets are the most appreciated as mineral specimens and, in less degree despite their vivid and rich colors, for their potential as gem-quality materials. This study provides a complete gemological characterization of five faceted samples and others new information by means of Synchrotron X-ray computed micro-tomography imaging gem features. Electron-probe microanalysis (EMPA) and laser ablation\u2013inductively coupled plasma\u2013mass spectrometry (LA\u2013ICP\u2013MS) established that the chemical composition of garnets from different localities, resulted both close to pure andradite, enriched in light rare earth elements (LREE) with a positive Eu anomaly, and grossular-andradite solid solution (grandite), enriched in heavy rare earth elements (HREE). X-ray powder diffraction analyses indicate the possible coexistence of almost pure grossular and andradite. A spectroscopic approach, commonly used with gem-like material, by Raman and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, completes the characterization of the samples. The new data on the textural and geochemical features of the grandite and andradite garnets suggest local growth processes under various chemical and oxidation conditions of metasomatic and metamorphic fluids interacting with the host-rocks. Garnets represent long-lasting mineral records of the complex geological history of the Val d\u2019Ala rodingitic dikes during their oceanic- and subduction-related metamorphic evolution