Return-to-launch-site three degree of freedom analysis, constant inertial attitude during the fuel dissipation phase

Results are presented of a study to show the effect of selecting a constant inertial attitude during the fuel dissipation phase of a return-to-launch-site abort. Results are also presented which show that the selection of the constant inertial attitude will affect the arrival point on the range-velocity target line. An alternate selection of the inertial attitude will provide control over the trajectory shape

Virtual Site as an aid to first-year learning

Courses run by the School of the Built Environment have a range of entry requirements that enable diverse students and those with lower academic qualifications to gain entry. This results in a particular challenge for the Documentation & Estimating module, which is a very practical, skillsand competence-based module. It is delivered to large tutorial cohorts of mixed courses, abilities, ages and experience. Many students need one-toone guidance to understand what, practically, they have to do. They are given the theory first in a lecture and then have practical tutorials to carry out assessed exercises with limited tutor contact time. The module includes some basic surveying techniques and a levelling exercise which involves the transfer of a level from an assumed benchmark to establish a temporary benchmark some distance away. Many students have problems with computation of results. In spite of a careful introduction and explanation of the use of the instruments and techniques, many students find it difficult to visualise what is happening

Calcareous nannofossils from the Eocene North Atlantic Ocean (IODP Expedition 342 Sites U1403-1411)

Integrated Ocean Drilling Program Expedition 342 (June-July 2012) cored nine sites and 18 holes (Sites U1403-U1411) on the J-Anomaly and the Southeast Newfoundland ridges in the NW Atlantic Ocean. These sites recovered sections ranging from Pleistocene to upper Albian, but the expedition particularly focussed on the recovery of expanded Paleogene successions with high quality microfossil preservation. This was achieved by choosing sites with thick packages of drift-type sediments on topographic highs that would maximise the preservation of carbonate. The expedition suceeded in recovering middle Eocene to lower Oligocene and upper Oligocene to lower Miocene high sedimentation rate sediment sequences with very well preserved microfossils. Highlights of the expedition include the recovery of continuous Eocene/Oligocene and Oligocene/Miocene boundaries, a Cretaceous-Paleogene boundary section with intact spherule layer, and Cenomanian/Turonian section with a 44 cm black shale. Here, we describe notable aspects of the Eocene nannofossil record, including the exceptional preservation and the evolution of several important Eocene groups: Nannotetrina, the Sphenolithus furcatolithoides group, the Reticulofenestra bisecta group and the Coccolithus gigas group. We also present a taxonomic overview of the Eocene nannofossil assemblages from Sites U1403-1411, illustrating 164 taxa and describing 25 new species (Blackites friedrichii, Blackites sextonii, Blackites subtilis, Calcidiscus scullyae, Clausicoccus norrisii, Coccolithus hulliae, Coccolithus opdykei, Cruciplacolithus nishii, Helicosphaera prolixa, Holodiscolithus agniniae, Holodiscolithus lippertii, Holodiscolithus liuii, Holodiscolithus whitesideae, Nannotetrina plana, Nannotetrina ruda, Neococcolithes purus, Neococcolithes radiatus, Pontosphaera brinkhuisii, Pontosphaera hollisii, Pontosphaera romansii, Pontosphaera wilsonii, Reticulofenestra magniscutum, Scyphosphaera interstincta, Semihololithus pseudobiskayae, Syracosphaera octiforma) and five new combinations (Blackites inversus, Pontosphaera zigzag, Reticulofenestra erbae, Reticulofenestra isabellae, Umbilicosphaera elliptica)

Changing the view:towards the theory of visualisation comprehension

The core problem of the evaluation of information visualisation is that the end product of visualisation - the comprehension of the information from the data - is difficult to measure objectively. This paper outlines a description of visualisation comprehension based on two existing theories of perception: principles of perceptual organisation and the reverse hierarchy theory. The resulting account of the processes involved in visualisation comprehension enables evaluation that is not only objective, but also non-comparative, providing an absolute efficiency classification. Finally, as a sample application of this approach, an experiment studying the benefits of interactivity in 3D scatterplots is presented

The Empirical Landscape of Trade Policy

This chapter surveys empirically the broad features of trade policy in goods for 31 major economies that collectively represented 83 percent of the world's population and 91 percent of the world's GDP in 2013. We address five questions: Do some countries have more liberal trading regimes than others? Within countries, which industries receive the most import protection? How do trade policies change over time? Do countries discriminate among their trading partners when setting trade policy? Finally, how liberalized is world trade? Our analysis documents the extent of cross-sectional heterogeneity in applied commercial policy across countries, their economic sectors, and their trading partners, over time. We conclude that substantial trade policy barriers remain as an important feature of the world economy.antidumpin

Biometry of Upper Cretaceous (Cenomanian-Maastrichtian) coccoliths - a record of long-term stability and interspecies size shifts

Biometric measurements of Mesozoic coccoliths (coccolith length and width) have been used in short-term biostratigraphic, taxonomic and palaeoecologic studies, but until now, not over longer time scales. Here, we present a long time-series study (∼ 30 million years) for the Upper Cretaceous, which aims to identify broad trends in coccolith size and to understand the factors governing coccolith size change over long time scales. We have generated biometric data for the dominant Upper Cretaceous coccolith groups, Broinsonia/Arkhangelskiella, Prediscosphaera, Retecapsa and Watznaueria, from 36 Cenomanian–Maastrichtian (100.5–66 Ma) samples from Goban Spur in the northeast Atlantic (DSDP Site 549). These data show that the coccolith sizes within Prediscosphaera, Retecapsa and Watznaueria were relatively stable through the Late Cretaceous, with mean size variation less than 0.7 μm. Within the Broinsonia/Arkhangelskiella group there was more pronounced variation, with a mean size increase from ∼ 6 μm in the Cenomanian to ∼ 10 μm in the Campanian. This significant change in mean size was largely driven by evolutionary turnover (species origination and extinctions), and, in particular, the appearance of larger species/subspecies (Broinsonia parca parca, Broinsonia parca constricta, Arkhangelskiella cymbiformis) in the early Campanian, replacing smaller species, such as Broinsonia signata and Broinsonia enormis. Shorter-term size fluctuations within Broinsonia/Arkhangelskiella, observed across the Late Cenomanian–Turonian and Late Campanian–Maastrichtian intervals, may, however, reflect changing palaeoenvironmental conditions, such as sea surface temperature and nutrient availability. / Les dimensions des coccolithes du Mésozoïque (longueur et largeur) ont été utilisées dans des études biostratigraphiques, taxonomiques et paléoécologiques sur le court-terme mais jusqu’à présent, jamais sur le long-terme. Ici, nous présentons l’étude d’une série chronologique à échelle de temps longue (∼ 30 millions d’années) du Crétacé supérieur, visant à identifier les tendances générales de leur taille et de comprendre les facteurs gouvernant les changements de taille des coccolithes sur une échelle de temps longue. Nous avons généré des données biométriques pour les groupes de coccolithes dominants au Crétacé supérieur, Broinsonia/Arkhangelskiella, Prediscosphaera, Retecapsa et Watznaueria, sur 36 échantillons du Cénomanien–Maastrichtien (100,5–66 Ma) provenant du Goban Spur dans l’Atlantique Nord-Est (DSDP Site 549). Ces données montrent que la taille des coccolithes appartenant aux groupes Prediscosphaera, Retecapsa et Watznaueria fut relativement stable durant tout le Crétacé supérieur, avec une variation de la taille moyenne inférieure à 0,7 μm. Au sein du groupe Broinsonia/Arkhangelskiella, les variations furent plus prononcées, avec une augmentation de la taille moyenne de ∼ 6 μm au Cénomanien jusqu’à ∼ 10 μm au Campanien. Ce changement significatif de la taille moyenne fut largement dû aux processus évolutifs (spéciations et extinctions), et en particulier à l’apparition d’espèces/sous-espèces plus larges (Broinsonia parca parca, Broinsonia parca constricta, Arkhangelskiella cymbiformis) au Campanien inférieur, remplaçant des espèces plus petites, telles que Broinsonia signata et Broinsonia enormis. Cependant, les fluctuations à court-terme au sein du groupe Broinsonia/Arkhangelskiella, observées aux transitions Cénomanien–Turonien et Campanien–Maastrichtien, pourraient refléter un changement des conditions paléoenvironnementales, telles que la température superficielle des eaux océaniques et la disponibilité en nutriment

THE ORIGIN OF \u3ci\u3eCHUBUTOLITHES\u3c/i\u3e IHERING, ICHNOFOSSILS FROM THE EOCENE AND OLIGOCENE OF CHUBUT PROVINCE, ARGENTINA

ABSTRACT-The distinctive trace fossil Chubutolithes gaimanensis n. ichnosp. occurs in Casamayoran (early Eocene) and Colhuehaupian (late Oligocene) alluvial rocks of the Sarmiento Formation in eastern Chubut Province, Argentina. Though known for nearly 70 years, its origin has remained obscure. Examination of new specimens and comparisons with modem analogs demonstrate that specimens of Chubutolithes represent the fossil nests of a mud-dauber (Hymenoptera: Sphecidae). Virtually identical nests are constructed today by mud-daubers in areas as disparate as southern Santa Cruz Province, Argentina, and Nebraska, confirming that quite similar trace fossils can be produced by several different taxa in a higher taxonomic clade. No satisfactory ethological term exists for trace fossils that, like Chubutolithes, were constructed by organisms above, rather than within, a substrate or medium. The new term aedificichnia is proposed. Chubutolithes occurs in alluvial paleosols and is associated with a large terrestrial ichnofauna. These trace fossils include the nests of scarab beetles, compound nests of social insects, and burrows of earthworms

Middle Eocene large coccolithaceans: Biostratigraphic implications and paleoclimatic clues

A combined light microscope-scanning electron microscope study of exceptionally well-preserved calcareous nannofossil assemblages from clay-rich middle Eocene sediments recovered at IODP Site U1410 (NW Atlantic Ocean) has enabled us to document a new evolutionary lineage within Coccolithus-like placoliths that have well-developed near-axial or diagonal cross-bars in their central-area. Based on our observations, we describe a new genus Pletolithus, a new species Pletolithus giganteus and four new combinations (Pletolithus opdykei, Pletolithus staurion, Pletolithus mutatus and Pletolithus gigas). The distinctive ultra-structures of the different morphotypes and the presence of transitional morphologies suggest that Pletolithus evolved from a morphological variant of Coccolithus. The evolution of this group of coccolithaceans is initially characterized by increasing size and the appearance of delicate axial cross-bars in the central-area. Size continues to increase in these coccoliths and the orientation of the cross-bars shifts to asymmetric and diagonal in later representatives. Morphometric measurements on P. gigas and the morphologically similar P. giganteus, provide evidence for the presence of two distinct populations allowing for an objective differentiation of these two species, which in turn provides unambiguous taxonomic definition for the important biostratigraphic marker species P. gigas. These data improve the reliability of middle Eocene biostratigraphy and show that this lineage appeared when a new equilibrium in the environmental conditions was reached and intriguingly it coincides with a remarkable change in the deep circulation of the North Atlantic Ocean

Muted calcareous nannoplankton response at the Middle/Late Eocene Turnover event in the western North Atlantic

Key extinctions in two major planktonic foraminiferal groups and high taxic turnover in radiolarians have led to the identification of the Middle/Late Eocene Turnover (MLET) and point towards significant palaeoclimatic and/or palaeoceanographic changes at around 38 million years ago. Here we present quantitative calcareous nannofossil data from Ocean Drilling Program Site 1052 (Blake Nose, western North Atlantic) in order to investigate the response of phytoplankton during the MLET. Our data show only minor shifts in taxon abundance, with no strong trends identified through the interval and no nannofossil origination or extinction events associated with the MLET. The assemblages are characterised by the dominance of neritic braarudosphaerids and eurytopic reticulofenestrids. The increased abundance of warm to temperate and mesotrophic nannofossils (Reticulofenestra reticulata, Reticulofenestra bisecta and Coccolithus pelagicus) in and around the MLET occur against a backdrop of cooling, as indicated by oxygen isotopes, suggesting that changing nutrient conditions was the principle driver of these shifts in the nannoplankton assemblage. This is further supported by an increase in radiolarian accumulation rates at this time. The lack of response in the calcareous nannoplankton relative to the zooplanktonic planktonic foraminifera and radiolaria demonstrates the contrasting sensitivity to environmental change in these different plankton groups, with radiolarians showing the highest degree of change at the MLET and the nannoplankton showing little or none