A new species of Craspedisia (Araneae: Theridiidae) in Miocene Dominican amber, imaged using X-ray computed tomography

Penney, David; Green, DI; McNeil, Andrew; Bradley, R. H.; Marusik, YM; Withers, Philip J.; Preziosi, Richard F.

doi:10.1134/s0031030112060093

Cited by 11 publications

(7 citation statements)

References 27 publications

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“…Indeed it has proved invaluable in imaging fossils using lab sources. 15,16 However because the incident beam is polychromatic, phase retrieval is not as effective as for synchrotron X-ray imaging. 17 Analyser-based diffraction enhanced imaging 18,19 involves the reflection of the transmitted beam from a Bragg crystal which acts as an angular filter converting refractive effects caused by the object into intensity effects in the detector plane.…”

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confidence: 99%

Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

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X-ray computer tomography (CT) is fast becoming an accepted tool within the materials science community for the acquisition of 3D images. Here the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one. Our review considers first the image acquisition process, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight (e.g. fast and high resolution imaging, crystallite (grain) imaging) than conventional attenuation based tomography. Methods and shortcomings of CT are examined for the quantification of 3D volumetric data to extract key topological parameters such as phase fractions, phase contiguity, and damage levels as well as density variations. As a non-destructive technique, CT is an ideal means of following structural development over time via time lapse sequences of 3D images (sometimes called 3D movies or 4D imaging). This includes information needed to optimise manufacturing processes, for example sintering or solidification, or to highlight the proclivity of specific degradation processes under service conditions, such as intergranular corrosion or fatigue crack growth. Besides the repeated application of static 3D image quantification to track such changes, digital volume correlation (DVC) and particle tracking (PT) methods are enabling the mapping of deformation in 3D over time. Finally the use of CT images is considered as the starting point for numerical modelling based on realistic microstructures, for example to predict flow through porous materials, the crystalline deformation of polycrystalline aggregates or the mechanical properties of composite materials.

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confidence: 99%

Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

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601

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“…In summary, 76% of all species belonged to families that were shared between both deposits and this value is most likely to rise, rather than fall, as a result of new fossil spider descriptions (e.g. Penney 2009 ; Penney et al 2011 , in press ; Saupe et al 2010 ; Wunderlich 2008 , 2011 ). These data are based on relatively young Tertiary fossils, so their similarity to the extant fauna should not be a great surprise.…”

Section: Discussionmentioning

confidence: 96%

Summary statistics for fossil spider species taxonomy

Penney¹,

Dunlop²,

Marusik³

2012

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Spiders (Araneae) are one of the most species-rich orders on Earth today, and also have one of the longest geological records of any terrestrial animal groups, as demonstrated by their extensive fossil record. There are currently around 1150 described fossil spider species, representing 2.6% of all described spiders (i.e. extinct and extant). Data for numbers of fossil and living spider taxa described annually (and various other metrics for the fossil taxa) were compiled from current taxonomic catalogues. Data for extant taxa showed a steady linear increase of approximately 500 new species per year over the last decade, reflecting a rather constant research activity in this area by a large number of scientists, which can be expected to continue. The results for fossil species were very different, with peaks of new species descriptions followed by long troughs, indicating minimal new published research activity for most years. This pattern is indicative of short bursts of research by a limited number of authors. Given the frequent discovery of new fossil deposits containing spiders, a wealth of new material coming to light from previously worked deposits, and the application of new imaging techniques in palaeoarachnology that allow us to extract additional data from historical specimens, e.g. X-ray computed tomography, it is important not only to ensure a sustained research activity on fossil spiders (and other arachnids) through training and enthusing the next generation of palaeoarachnologists, but preferably to promote increased research and expertise in this field.

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“…When the method of Paganin et al [1] (PM) is utilised in a tomographic context [21], its domain of utility broadens since many objects may be viewed as locally composed of a single material of interest, in three spatial dimensions, even though they cannot be described as composed of a single material in projection [22,23]. Examples of applications of the PM in a tomographic setting include the imaging of paper [21], polymer micro-wire composites [24], high-Weber-number water jets [25], self healing thermoplastics [26], paint-primer microstructure [27], sandstone micro-structure [28], granite [29], melting snow [30], anthracite coal [31], evolving liquid foams [32], iron oxide particles in mouse brains [33,34], rat brains [23], mouse lungs [35], rabbit lungs [23], mouse tibiae [36], crocodile teeth [37], mosquitoes [6], fly legs [21], high speed in vivo imaging of a fly's flight motor system [38], wood [24], dynamic crack propagation in heat treated hardwood [39], rose peduncles [40], amber-fossilised spiders [41,42], amberfossilised centipedes [43], fossilised rodent teeth [44], fossil bones [45], ancient cockroach coprolites [46], fossilised earlyanimal embryos [47], fossil muscles of primitive vertebrates [48,49] and the vertebral architecture of ancient tetrapods [50]. The preceding list is restricted to papers published prior to 2014.…”

Section: Introductionmentioning

confidence: 99%

Boosting spatial resolution by incorporating periodic boundary conditions into single-distance hard-x-ray phase retrieval

Paganin¹,

Favre‐Nicolin²,

Mirone³

et al. 2020

J. Opt.

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A simple coherent-imaging method due to Paganin et al. is widely employed for phase-amplitude reconstruction of samples using a single paraxial x-ray propagation-based phase-contrast image. The method assumes that the sample-to-detector distance is sufficiently small for the associated Fresnel number to be large compared to unity. The algorithm is particularly effective when employed in a tomographic setting, using a single propagation-based phase-contrast image for each projection.Here we develop a simple extension of the method, which improves the reconstructed contrast of very fine sample features. This provides first-principles motivation for boosting fine spatial detail associated with high Fourier frequencies, relative to the original method, and was inspired by several recent works employing empirically-obtained Fourier filters to a similar end.

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A new species of Craspedisia (Araneae: Theridiidae) in Miocene Dominican amber, imaged using X-ray computed tomography

Cited by 11 publications

References 27 publications

Quantitative X-ray tomography

Quantitative X-ray tomography

Summary statistics for fossil spider species taxonomy

Boosting spatial resolution by incorporating periodic boundary conditions into single-distance hard-x-ray phase retrieval

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