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The deep biosphere of the subseafloor crust is believed to contain a significant part of Earth's biomass, but because of the difficulties of directly observing the living organisms, its composition and ecology are poorly known. We report here a consortium of fossilized prokaryotic and eukaryotic micro-organisms, occupying cavities in deep-drilled vesicular basalt from the Emperor Seamounts, Pacific Ocean, 67.5m below seafloor (mbsf). Fungal hyphae provide the framework on which prokaryote-like organisms are suspended like cobwebs and iron-oxidizing bacteria form microstromatolites (Frutexites). The spatial inter-relationships show that the organisms were living at the same time in an integrated fashion, suggesting symbiotic interdependence. The community is contemporaneous with secondary mineralizations of calcite partly filling the cavities. The fungal hyphae frequently extend into the calcite, indicating that they were able to bore into the substrate through mineral dissolution. A symbiotic relationship with chemoautotrophs, as inferred for the observed consortium, may be a pre-requisite for the eukaryotic colonization of crustal rocks. Fossils thus open a window to the extant as well as the ancient deep biosphere., AuthorCount:7

This chapter makes a strong statement in favour of self-narration in adult education, both as a method for research and for intervention. A critical view of the most recent developments in the European policies and practices for adult education highlights the limits of a narrowing and reductive concept of lifelong learning, understood as mere adaptation to the labour market, while adult voices need to be listened, chronicled, and recognized. The need to take position, and allow learners to do the same, brings to political education, in its noblest meanings. Self-narration, framed in a critical view, becomes the process to voice alternative stories, silenced stories, and to create the basis for participation. In the last paragraph, qualitative research in adult education, in its more recent dialogical, participatory and critical versions, is signalled as a field to be developed to help policy makers and practitioners to meet academics so as to open possibilities for a better society .

Il tema dell'infanzia femminile contemporanea viene riletto in chiave pedagogico-critica attraverso le due categorie di inconscio e di potere.l'inconscio è, in questa prospettiva, quel concetto chiave che rende conto di come il confine generazionale tra adulti e bambini sia sia assottigliato e di come alcune dimensioni dell'inconscio d'infanzia continuino a sopravvivere nella genrazione adulta e rendano il rapporto madri figlie ancorato a stati di fusionalità affettiva e a difficoltàeducative nell'esercizio della funzione genitoriale dovute a un ecceso della funzione di rispecchiamento. Il tema del potere ci è utile per introdurre il versante sociale e per analizzare criticamente come l'immaginario mass-mediatico e quello dell'arte contemporanea si serve della categoria dell'infantile per produrre immagini di donne e bambine stereotipate e costruite sulla su una fantasia collettivamente diffusa di giovinezza perenne. Quest'analisi è utile per problematizzare in chiave pedagogica alcune zone residuali e di margine che svolgano una funzione di resistenza e nelel quali radicare nuovi orizzonti educativi percorribili.

Il contributo affronta, nella prima parte, il tema del cambiamento della ” forma -scuola” a partire da una rilettura critica del suo dispositivo e degli spazi dei suoi setting di apprendimento. La prospettiva epistemologica adottata è quella della clinica della formazione che pensa la scuola come un contesto educativo deputato a elaborare in modo intenzionale, sinergico e integrato i contributi che gli attori istituzionali portano dall’ambito della vita diffusa. Una scuola intesa come spazio teatrale di elaborazione della complessità del mondo vitale, viene proposta come antidoto e cura radicale ai malesseri che affliggono la formazione scolastica contemporanea, sempre più appiattita su mandati di performance e sempre più inadeguata a sostenere il compito di crescita e di maturazione evolutiva delle giovani generazioni nel contesto della scuola. L’apertura della scuola a nuovi linguaggi divergenti e a nuove forme di comunicazione che interrompano l’automaticità della lezione tradizionale, centrata sul primato di un sapere astratto, viene interpretata in chiave critica, come capacità di allestire la scena dell’aula come spazio tridimensionale, aperto alla profondità dei vissuti e dei saperi che i giovani portano e come sfondo integratore, capace di utilizzare le piste di apprendimento come occasioni per elaborare una cultura ampia e aperta anche all’elaborazione dei vissuti emotivi e fantasmatici che si animano nella scena della classe. In questo senso, la comunicazione perde il suo significato strategico e strumentale per divenire forma intenzionata di predisposizione di un setting in cui dare significato non solo agli elementi di compito ma anche a quelle latenze che si muovono nel “sottobanco” dell’esperienza scolastica Nella seconda parte del contributo vengono delineate le ipotesi di lavoro di un progetto di ricerca-formazione destinato agli insegnanti della scuola secondaria e agli studenti attraverso il dispositivo cinematografico. L’esperienza visuale

Teeth and jaws constitute a model of the evolutionary developmental biology concept of modularity and they have been considered the key innovations underpinning a classic example of adaptive radiation. However, their evolutionary origins are much debated. Placoderms comprise an extinct sister clade or grade to the clade containing chondrichthyans and osteichthyans, and although they clearly possess jaws, previous studies have suggested that they lack teeth, that they possess convergently evolved tooth-like structures or that they possess true teeth. Here we use synchrotron radiation X-ray tomographic microscopy (SRXTM) 13 of a developmental series of Compagopiscis croucheri (Arthrodira) to show that placoderm jaws are composed of distinct cartilages and gnathal ossifications in both jaws, and a dermal element in the lower jaw. The gnathal ossification is a composite of distinct teeth that developed in succession, polarized along three distinct vectors, comparable to tooth families. The teeth are composed of dentine and bone, and show a distinct pulp cavity that is infilled centripetally as development proceeds. This pattern is repeated in other placoderms, but differs from the structure and development of tooth-like structures in the postbranchial lamina and dermal skeleton of Compagopiscis and other placoderms. We interpret this evidence to indicate that Compagopiscis and other arthrodires possessed teeth, but that tooth and jaw development was not developmentally or structurally integrated in placoderms. Teeth did not evolve convergently among the extant and extinct classes of early jawed vertebrates but, rather, successional teeth evolved within the gnathostome stem-lineage soon after the origin of jaws. The chimaeric developmental origin of this model of modularity reflects the distinct evolutionary origins of teeth and of component elements of the jaws.

Sub-second temporal-resolution tomographic microscopy is becoming a reality at third-generation synchrotron sources. Efficient data handling and post-processing is, however, difficult when the data rates are close to 10 GB s-1. This bottleneck still hinders exploitation of the full potential inherent in the ultrafast acquisition speed. In this paper the fast reconstruction algorithm gridrec, highly optimized for conventional CPU technology, is presented. It is shown that gridrec is a valuable alternative to standard filtered back-projection routines, despite being based on the Fourier transform method. In fact, the regridding procedure used for resampling the Fourier space from polar to Cartesian coordinates couples excellent performance with negligible accuracy degradation. The stronger dependence of the observed signal-to-noise ratio for gridrec reconstructions on the number of angular views makes the presented algorithm even superior to filtered back-projection when the tomographic problem is well sampled. Gridrec not only guarantees high-quality results but it provides up to 20-fold performance increase, making real-time monitoring of the sub-second acquisition process a reality.

Water management is an important factor for optimizing polymer electrolyte fuel cells (PEFC) under high current density conditions as required for the automotive application. The characteristics of the local liquid saturation of the gas diffusion layer (GDL) is of particular interest. Here we report on the development of in-situ X-ray tomographic microscopy (XTM) with a pixel sizes in the order of 2 μm and sensitivity for carbon and liquid water for the quantitative analysis of liquid water in GDLs. In-situ XTM of PEFC is a major experimental challenge. A complete cell needs to be operated under realistic conditions in the constraint space of the small field of view on the beamline sample stage. Further phase segmentation of the images is required to successfully analyze the quantitative properties of the different phases. For this a workflow, applying differential images between dry and wet structures has been developed. Cells with Toray TGP-H-060 GDLs were analyzed in-situ. Droplets that appear on the GDL surface are connected to a significant water structure inside the GDL. Further the water cluster size distribution in the GDL shows that while small droplets (<100 pl) are numerous, most of the water is contained in few larger clusters., QC 20140917

We report on a setup for differential x-ray phase-contrast imaging and tomography, that measures the full 2D phase-gradient information. The setup uses a simple one-dimensional x-ray grating interferometer, in which the grating structures of the interferometer are oriented at a tilt angle with respect to the sample rotation axis. In such a configuration, the differential phase images from opposing tomography projections can be combined to yield both components of the gradient vector. We show how the refractive index distribution as well as its x, y, and z gradient components can be reconstructed directly from the recorded projection data. The method can equally well be applied at conventional x-ray tube sources, to analyzer based x-ray imaging or neutron imaging. It is demonstrated with measurements of an x-ray phantom and a rat brain using synchrotron radiation.

At the TOMCAT (TOmographic Microscopy and Coherent rAdiology experimenTs) beamline of the Swiss Light Source with an energy range of 8-45 keV and voxel size from 0.37 µm to 7.4 µm, full tomographic datasets are typically acquired in 5 to 10 min. To exploit the speed of the system and enable high-throughput studies to be performed in a fully automatic manner, a package of automation tools has been developed. The samples are automatically exchanged, aligned, moved to the correct region of interest, and scanned. This task is accomplished through the coordination of Python scripts, a robot-based sample-exchange system, sample positioning motors and a CCD camera. The tools are suited for any samples that can be mounted on a standard SEM stub, and require no specific environmental conditions. Up to 60 samples can be analyzed at a time without user intervention. The throughput of the system is dependent on resolution, energy and sample size, but rates of four samples per hour have been achieved with 0.74 µm voxel size at 17.5 keV. The maximum intervention-free scanning time is theoretically unlimited, and in practice experiments have been running unattended as long as 53 h (the average beam time allocation at TOMCAT is 48 h per user). The system is the first fully automated high-throughput tomography station: mounting samples, finding regions of interest, scanning and reconstructing can be performed without user intervention. The system also includes many features which accelerate and simplify the process of tomographic microscopy.

Water transport in wood is vital for the survival of trees. With synchrotron radiation X-ray tomographic microscopy (SRXTM), it has become possible to characterize and quantify the three-dimensional (3D) network formed by vessels that are responsible for longitudinal transport. In the present study, the spatial size dependence of vessels and the organization inside single growth rings in terms of vessel-induced porosity was studied by SRXTM. Network characteristics, such as connectivity, were deduced by digital image analysis from the processed tomographic data and related to known complex network topologies.

The penetrating power of X-rays coupled with the high flux of 3rd generation synchrotron sources makes X-ray tomography to excel among fast imaging methods . To exploit this asset of synchrotron sources is the motivation for setting up an ultra-fast tomography endstation at the TOMCAT beamline. The state of the art instruments at synchrotron sources offer routinely a temporal resolution of tens of seconds in tomography. For a number of applications, for example biomedical studies, the relevant time scales (breathing, heartbeat) are rather in the range of 0.5–2 seconds. To overcome motion artifacts when imaging such systems a new ultra-fast tomographic data acquisition scheme is being developed at the TOMCAT beamline. We can acquire a full set of projections at sub-second timescale in monochromatic or white-beam configuration. We present a feasibility study with the ultimate aim to achieve sub-second temporal resolution in 3D without significant deterioration of the spatial resolution. For the first time, the 3D dynamics of the very early stages of a quickly aging liquid foam can be visualised with high quality and sufficiently large field of view. ©2010 American Institute of Physics

Synchrotron‐based full‐field tomographic microscopy established itself as a tool for noninvasive investigations. Many beamlines worldwide routinely achieve micrometer spatial resolution while the isotropic 100‐nm barrier is reached and trespassed only by few instruments, mainly in the soft x‐ray regime. We present an x‐ray, full‐field microscope with tomographic capabilities operating at 10 keV and with a 3D isotropic resolution of 144 nm recently installed at the TOMCAT beamline of the Swiss Light Source. Custom optical components, including a beam‐shaping condenser and phase‐shifting dot arrays, were used to obtain an ideal, aperture‐matched sample illumination and very sensitive phase‐contrast imaging. The instrument has been successfully used for the nondestructive, volumetric investigation of single, unstained cells.

During its first four years of life, the TOMCAT beamline [1] at the Swiss Light Source has established itself as a state‐of‐the art hard x‐ray tomographic microscopy endstation for experiments on a large variety of samples, ranging from the fields of biology to materials science. It routinely performs absorption as well as phase‐contrast imaging with an isotropic voxel size ranging from 0.360 up to 14.8 microns. Phase contrast is obtained either with simple edge‐enhancement, a modified transport of intensity approach [2] or grating interferometry [3]. Typical acquisition times are on the order of a few minutes, depending on energy and resolution. A recently implemented automatic sample exchanger is now available for high‐throughput studies [4]. In addition to further developments in phase‐contrast imaging, current scientific activities at the beamline focus on pushing spatial and temporal resolution by a few orders of magnitude, aiming at nano‐ [5] and “real‐time” [6] tomography.

Volumetric data at micrometer level resolution can be acquired within a few minutes using synchrotron-radiation-based tomographic microscopy. The field of view along the rotation axis of the sample can easily be increased by stacking several tomograms, allowing the investigation of long and thin objects at high resolution. On the contrary, an extension of the field of view in the perpendicular direction is non-trivial. This paper presents an acquisition protocol which increases the field of view of the tomographic dataset perpendicular to its rotation axis. The acquisition protocol can be tuned as a function of the reconstruction quality and scanning time. Since the scanning time is proportional to the radiation dose imparted to the sample, this method can be used to increase the field of view of tomographic microscopy instruments while optimizing the radiation dose for radiation-sensitive samples and keeping the quality of the tomographic dataset on the required level. This approach, dubbed wide-field synchrotron radiation tomographic microscopy, can increase the lateral field of view up to five times. The method has been successfully applied for the three-dimensional imaging of entire rat lung acini with a diameter of 4.1 mm at a voxel size of 1.48 microm.

The European Plate has a 4.5 Gy long and complex tectonic history. This is reflected in the present-day large-scale crustal structures. A new digital Moho depth map is compiled from more than 250 data sets of individual seismic profiles, 3-D models obtained by body and surface waves, receiver function results and maps of seismic and/or gravity data compilations. We have compiled the first digital, high-resolution map of the Moho depth for the whole European Plate, extending from the mid-Atlantic ridge in the west to the Ural Mountains in the east, and from the Mediterranean Sea in the south to the Barents Sea and Spitsbergen in the Arctic in the north. In general, three large domains within the European Plate crust are visible. The oldest Archean and Proterozoic crust has a thickness of 40–60 km, the continental Variscan and Alpine crust has a thickness of 20–40 km, and the youngest oceanic Atlantic crust has a thickness of 10–20 km.

Phase-sensitive X-ray imaging methods can provide substantially increased contrast over conventional absorption-based imaging, and therefore new and otherwise inaccessible information. Differential phase-contrast (DPC) imaging, which uses a grating interferometer and a phase-stepping technique, has been integrated into TOMCAT, a beamline dedicated to tomographic microscopy and coherent radiology experiments at the Swiss Light Source. Developments have been made focusing on the fast acquisition and post-processing of data to enable a high-throughput of samples, with obvious advantages, also through increasing the efficiency of the detecting system, of helping to reduce radiation dose imparted to the sample. A novel aquarium design allows a vertical rotation axis below the sample with measurements performed in aqueous environment. Optimization of the data acquisition procedure enables a full phase volume (1024 x 1024 pixels x 1000 projections x 9 phase steps, i.e. 9000 projections in total) to be acquired in 20 min (with a pixel size of 7.4 microm), and the subsequent post-processing has been integrated into the beamline pipeline for sinogram generation. Local DPC tomography allows one to focus with higher magnification on a particular region of interest of a sample without the presence of local tomography reconstruction artifacts. Furthermore, 'widefield' imaging is shown for DPC scans for the first time, enabling the field of view of the imaging system to be doubled for samples that are larger than the magnification allows. A case study is illustrated focusing on the visualization of soft tissue features, and particularly the substantia nigra of a rat brain. Darkfield images, based on local X-ray scattering, can also be extracted from a grating-based DPC scan: an example of the advantages of darkfield contrast is shown and the potential of darkfield X-ray tomography is discussed.

X-ray microscopy greatly benefits from the advances in x-ray optics. At the Paul Scherrer Institut, developments in x-ray diffractive optics include the manufacture and optimization of Fresnel zone plates (FZPs) and diffractive optical elements for both soft and hard x-ray regimes. In particular, we demonstrate here a novel method for the production of ultra-high resolution FZPs. This technique is based on the deposition of a zone plate material (iridium) onto the sidewalls of a prepatterned template structure (silicon) by atomic layer deposition. This approach overcomes the limitations due to electron-beam writing of dense patterns in FZP fabrication and provides a clear route to push the resolution into sub-10 nm regime. A FZP fabricated by this method was used to resolve test structures with 12 nm lines and spaces at the scanning transmission x-ray microscope of the PolLux beamline of the Swiss Light Source at 1.2 keV photon energy.