69 research outputs found
Knowlton Circles: A Later Neolithic and Early Bronze Age Ceremonial Complex and Its EnvironsâA Review
The larger henge monuments of Wessex have been the focus of detailed archaeological investigation for over a century and consequently their study has provided a greater, albeit fragmentary, understanding of later Neolithic society. For the most part such studies have continued to show that these great mega-structures of the third millennium B.C. persist as beacons of ceremonial functionality into which later societies invested much of themselves, intellectually, spiritually and unquestionably physically. While Stonehenge, Avebury and Durrington Walls continue to attract a great deal of attention with ongoing research, comparable sites in Dorset have been less well researched. Two campaigns of archaeological investigation undertaken in the Allen Valley of east Dorset by the author have focussed upon the complex of earthworks at Knowlton and additionally at one of three broadly contemporary barrow cemeteries located nearby. The findings from these investigations are beginning to shed more light on the possible origins and development of these important but weakly understood landscapes. This paper outlines some of the main findings from these investigations and posits a chronological framework for the integration of a group of monuments that formed both a ceremonial landscape and a geographical and spiritual home for communities that lasted for a thousand years
Multi-system neurological disease is common in patients with OPA1 mutations
Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal âdominant optic atrophy plusâ variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44â6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08â4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment
Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run
Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society
Luminescent rhenium fac-tricarbonyl-containing complexes of androgenic oxo-steroids
A new route to luminescent derivatives of androgenic steroids containing a ketone group in the 3-
or 17-position has been developed. Reaction with the fac-Re(CO)3Cl complex of 3,3â-diamino-2,2â-
bipyridine (complex 1) afforded a cyclic aminal product with different steroids. The rate of reaction
and yield varies according to the conjugation or steric hindrance around the ketone grou
Are the Kimmeridge Clay deposits affected by âburn-downâ events? Palynological and geochemical studies on a 1 metre long section from the Upper Kimmeridge Clay Formation (Dorset, UK)
Two independent analytical approaches, palynology and inorganic geochemistry, were applied to identify potential oxygen âburn-downâ events in the Late Jurassic Kimmeridge Clay Formation (KCF). The KCF interval of the rotunda ammonite zone, spanning 121.82â122.72 m depth was sampled from the Swanworth Quarry 1 borehole (Dorset, UK) at 2.5â5.0 cm resolution. Samples were analysed for total organic carbon (TOC), concentrations of elements that are known to be productivity- and/or nutrient-related (e.g. Cu, P), detrital (e.g. Al, Ti, Zr) and redox-sensitive/sulphide-forming (e.g. V, Mo, Fe, Mn, S), and palynofacies components including analysis of organic-walled dinoflagellate cysts (dinocysts) on a species level.The TOC contents generally exceed 2 wt.%, with a maximum of 8.8 wt.% at 122.37 cm depth and elevated values in the central part of the investigated interval. This interval of relatively higher TOC values correlates well with the maximum recovery of marine palynomorphs and low Al values, suggesting that the TOC is primarily of marine organic matter (OM).Changes in V/Al, Mo/Al, Fe/Al, Mn/Al and S patterns at 122.37 m depth mark a shift from anoxic conditions in the lower part of the studied interval to more oxic conditions in its upper part. Such a shift could explain the relatively high TOC and marine palynomorph concentrations in the lower part of the studied interval as a result of better preservation, and the subsequent decrease as an effect of a post-depositional âburn-downâ, i.e. OM oxidation. As the amount of marine palynomorphs and TOC content diminishes from the middle part of the section upwards, species-specific changes in dinocyst assemblages can be observed. In particular, concentrations of Circulodinium spp., Cyclonephelium spp., Sirmiodinium grossi, Senoniasphaera jurassica and Systematophora spp. decrease rapidly in comparison to other species, such as Glossodinium dimorphum and Cribroperidinium sp. 1, which may suggest selective degradation of dinocysts due to oxidation.We suggest that post-depositional oxygenation of bottom and pore waters within the sediment was most probably the cause for decreasing TOC values and reduced recovery of marine palynomorphs towards the top of the studied interval in comparison to high TOC and marine palynomorph values in the central part of the studied interval due to anoxic conditions.<br/
The composition and diversity of dinosporin in species of the Apectodinium complex (Dinoflagellata)
Organic-walled dinoflagellate cysts, produced as a result of sexual reproduction, are important tools for studies on recent and past environments. Additionally, the organic-walled cysts can be used as proxies for understanding the composition and chemical transformations of marine kerogen, the largest global organic carbon pool. However, any usage of dinoflagellate cysts in this manner is predicated on an understanding of the composition and transformations of this potential proxy. Dinoflagellate cyst walls are composed of âdinosporinâ, a refractory biomacromolecule that probably represents a suite of chemically distinct biopolymers. In order to investigate both the nature of dinosporin and the extent to which the composition of this biomacromolecule may differ between dinoflagellate cyst taxa, we analyzed cyst species from the genus Apectodinium. The species defined within this genus are visually similar with several seeming to represent end-members along a continuum of morphological variation. Micro-Fourier transform infrared (FTIR) analysis was performed on three of these morphospecies (identified visually as A. paniculatum, A. parvum and A. augustum) from two regionally distinct samples. The analyses showed consistent patterns with clear differences between the species. The dinosporin of A. paniculatum closely resembles cellulose and is rich in ether bonds (Csingle bondO), while the dinosporin of A. augustum contains more carboxyl (COOH) groups. A. parvum appears intermediate in many respects, despite representing an end-member in terms of morphology. These differences are consistent regardless of the regional setting or post-depositional conditions, and strongly suggest that the original cyst wall composition of the species differed when the cysts were formed. These data are the first to clearly show differences in cyst wall composition between species of the same genus and indicate that the chemical diversity of dinosporins is greater than previously thought
Differences in the chemical composition of organic-walled dinoflagellate resting cysts from phototrophic and heterotrophic dinoflagellates
Dinoflagellates constitute a large proportion of the planktonic biomass from marine to freshwater environments. Some species produce a preservable organic-walled resting cyst (dinocyst) during the sexual phase of their life cycle that is an important link between the organisms, the environment in which their parent motile theca grew, and the sedimentary record. Despite their abundance and widespread usage as proxy indicators for environmental conditions, there is a lack of knowledge regarding the dinocyst wall chemical composition. It is likely that numerous factors, including phylogeny and life strategy, determine the cyst wall chemistry. However, the extent to which this composition varies based on inherent (phylogenetic) or variable (ecological) factors has not been studied. To address this, we used micro-Fourier transform infrared (FTIR) spectroscopy to analyze nine cyst species produced by either phototrophic or heterotrophic dinoflagellates from the extant orders Gonyaulacales, Gymnodiniales and Peridiniales. Based on the presence of characteristic functional groups, two significantly different cyst wall compositions are observed that correspond to the dinoflagellate's nutritional strategy. The dinocyst wall compositions analyzed appeared carbohydrate-based, but the cyst wall produced by phototrophic dinoflagellates suggested a cellulose-like glucan, while heterotrophic forms produced a nitrogen-rich glycan. This constitutes the first empirical evidence nutritional strategy is related to different dinocyst wall chemistries. Our results indicated phylogeny was less important for predicting composition than the nutritional strategy of the dinoflagellate, suggesting potential for cyst wall chemistry to infer past nutritional strategies of extinct taxa preserved in the sedimentary record
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