1,160 research outputs found
Pyritized tube feet in a protasterid ophiuroid from the Upper Ordovician of Kentucky, U.S.A.
A single specimen of the protasterid ophiuroid Protasterina flexuosa from the Kope Formation (Cincinnatian, Upper Ordovician) of Kentucky exhibits threeâdimensionally pyritized tube feet. This represents the first report of softâtissue preservation in an echinoderm from the typeâCincinnatian series. The tube feet are solid and lack all internal structure. They consist of aggregated masses of small euhedral to subhedral pyrite crystals suggesting that pyritization, although decayâinduced and mediated, did not necessarily replicate softâtissues but might instead have formed inside the voidâspaces left behind during the decay process. The discovery of pyritized softâtissue as delicate as ophiuroid tube feet suggests that similar forms of softâtissue preservation might be found in other taxa in the Kope Formation. Perhaps much more importantly, this unexpected occurrence demonstrates the incompleteness of our knowledge of permissible conditions for the preservation of softâtissues and it thereby indicates promise for discovery of other such occurrences in diverse organisms in unexpected settings. Systematics of Paleozoic ophiuroids remains problematic in spite of many years of study by capable paleontologists. The incomplete but wellâpreserved specimens treated here include the types of Protasterina flexuosa and Protasterina fimbriata as well as previously undescribed specimens. Together they permit a revised diagnosis and detailed description of the genus Protasterina. Protasterina fimbriata is the type species of the genus but is a subjective junior synonym of Protaster flexuosus (= Protasterina flexuosa). The genus is clearly differentiated from the only other known protasterid ophiuroid from the Cincinnatian series, Taeniaster spinosus, and from all other protasterid genera
Analysis of the Impact and Value of Community Benefit Clauses in Procurement
This research draws on data from a large scale e-survey of public organisations and in-depth analysis of 24 individual contracts
Reflections on the dreamer examines his pillow - Scene 1
Senior Project submitted to The Division of Arts of Bard College
How Will the Czech Republic Achieve the EU Climate and Energy Targets?
This article argues that the Czech Republic should expand wind power to meet the ever-growing European Union renewable energy requirements and to achieve the Czech Republicâs State Energy Policy objectives. The country could save about $23 billion in initial investment costs by expanding only wind power instead of its current plan of using diversified renewable energy sources
Arithmetical structures on bidents
An arithmetical structure on a finite, connected graph is a pair of
vectors with positive integer entries for which
, where is
the adjacency matrix of and where the entries of have no
common factor. The critical group of an arithmetical structure is the torsion
part of the cokernel of . In this paper,
we study arithmetical structures and their critical groups on bidents, which
are graphs consisting of a path with two "prongs" at one end. We give a process
for determining the number of arithmetical structures on the bident with
vertices and show that this number grows at the same rate as the Catalan
numbers as increases. We also completely characterize the groups that occur
as critical groups of arithmetical structures on bidents.Comment: 32 page
Analysis of the Impact and Value of Community Benefit Clauses in Procurement
This research draws on data from a large scale e-survey of public organisations and in-depth analysis of 24 individual contracts
UAVM: Towards Unifying Audio and Visual Models
Conventional audio-visual models have independent audio and video branches.
In this work, we unify the audio and visual branches by designing a Unified
Audio-Visual Model (UAVM). The UAVM achieves a new state-of-the-art
audio-visual event classification accuracy of 65.8% on VGGSound. More
interestingly, we also find a few intriguing properties of UAVM that the
modality-independent counterparts do not have.Comment: Published in Signal Processing Letters. Code at
https://github.com/YuanGongND/uav
Analysis of building-integrated renewable energy systems in modern UK homes
Driven by climate change and the impending depletion of fossil fuels, the UK Government has set the great challenge to UK builders to produce zero-carbon homes as of 2016. Due to a lack of experience the merits of integrating onsite micro renewable energy systems were largely unknown. Barratt Development PLC, UK's largest builder, set out in 2006 to investigate how these new building regulations can best be tackled. The key points to be investigated are: how much CO2 can be offset using renewable energy systems in standard homes and at what cost; how reliable are these systems; and how can their performance be improved? At the EcoSmart village several systems were tested under realistic conditions, including PV, Solar Thermal, Micro Wind Turbines, GSHPs and microCHP. The systems were tested over a 12-month period, integrated into standard Barratt homes, and running under near real-life conditions. Data was recorded from the test-site, including heat and electrical energy generation and consumption, temperature data and weather data. This data was used to establish the theoretical performance of the systems at the test site, and by doing so simple methods were found and tested that can be used by builders or architects to gain a better understanding of the expected performance of a particular system. The estimated energy generation was then compared to the measured performance. Detailed modelling and analysis of observations was carried out to provide explanations for any discrepancies, and based on this general recommendations were made on how the performance of the systems could be improved. Given the commercial drivers behind carrying out this research project, a high emphasis was given to financial implications of installing the systems. For this purpose payback periods and life-time savings were estimated, based on measured performance and other influences such as feed-in tariffs. This was also done for embodied energy and embodied carbon, as this will ultimately determine how the systems can help to fulfil the purpose of Government legislation, which is to reduce the carbon footprint of the UK domestic sector.EThOS - Electronic Theses Online ServiceBarratt Developments PLCEPSRCGBUnited Kingdo
Fractal Scales in a Schwarzschild Atmosphere
Recently, Glass and Krisch have extended the Vaidya radiating metric to
include both a radiation fluid and a string fluid [1999 Class. Quantum Grav.
vol 16, 1175]. Mass diffusion in the extended Schwarzschild atmosphere was
studied. The continuous solutions of classical diffusive transport are believed
to describe the envelope of underlying fractal behavior. In this work we
examine the classical picture at scales on which fractal behavior might be
evident.Comment: to appear in Class. Quantum Gra
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