bluuebunny/crossref_metadata_2025 huggingface dataset:
Standardization of preanalytical aspects of cerebrospinal fluid biomarker testing for Alzheimer's disease diagnosis: A consensus paper from the Alzheimer's Biomarkers Standardization Initiative
Authors: Vanderstichele Hugo , Bibl Mirko , Engelborghs Sebastiaan , Le Bastard Nathalie , Lewczuk Piotr , Molinuevo Jose Luis , Parnetti Lucilla , Perret‐Liaudet Armand , Shaw Leslie M. , Teunissen Charlotte , Wouters Dirk , Blennow Kaj
Published: November 2011

Background

Numerous studies show that the cerebrospinal fluid biomarkers total tau (T‐tau), tau phosphorylated at threonine 181 (P‐tau181P), and amyloid‐β (1‐42) (Aβ1–42) have high diagnostic accuracy for Alzheimer's disease. Variability in concentrations for Aβ1–42, T‐tau, and P‐tau181P drives the need for standardization.

Methods

Key issues were identified and discussed before the first meeting of the members of the Alzheimer's Biomarkers Standardization Initiative (ABSI). Subsequent ABSI consensus meetings focused on preanalytical issues.

Results

Consensus was reached on preanalytical issues such as the effects of fasting, different tube types, centrifugation, time and temperature before storage, storage temperature, repeated freeze/thaw cycles, and length of storage on concentrations of Aβ1–42, T‐tau, and P‐tau181P in cerebrospinal fluid.

Conclusions

The consensus reached on preanalytical issues and the recommendations put forward during the ABSI consensus meetings are presented in this paper.
Countrywide strategic plans on Alzheimer's disease: Developing the framework for the international battle against Alzheimer's disease
Authors: Rosow Kyra , Holzapfel Andrew , Karlawish Jason H. , Baumgart Matthew , Bain Lisa J. , Khachaturian Ara S.
Published: November 2011

As the world's population ages, countries must prepare for the significant impact Alzheimer's disease will have on their health systems, their economies, and their citizens. In anticipation of major global demographic changes, many countries in the G‐20 since 2000 have begun to develop and enact plans to address Alzheimer's disease as a national priority. However, even with nearly half of these participating countries having plans in place, there has been little research done to quantify the value of enacting a countrywide plan on this disease. In this review, we summarize recent national plans (from the year 2000 and beyond) and any results stemming from their respective recommendations and activities.
Designing e‐government services: Key service attributes and citizens’ preference structures
Authors: Venkatesh Viswanath , Chan Frank K.Y. , Thong James Y.L.
Published: November 2011

Advances in Internet technologies have led to the popularity of technology‐based self‐services, with the design of such services becoming increasingly important. Using technology‐based services in the public sector as the setting, we identified the key service attributes driving adoption and use of transactional e‐government services, and citizens’ preference structures across these attributes. After identifying four key attributes, i.e., usability, computer resource requirement, technical support provision and security provision, we conducted a Web‐based survey and a conjoint experiment among 2465 citizens. In a two‐stage Web‐based survey, citizens reported their perceptions about a smartcard technology for transactional e‐government services before use, and their use and satisfaction 4 months later. Results showed that the key attributes (noted above) influenced citizens’ intentions, subsequent use and satisfaction. In the conjoint experiment, citizens reported their preferences for key service attributes for two transactional e‐government services. Further, a cluster analysis uncovered four distinct citizen segments, i.e., balanced, usability‐focused, risk‐conscious and resource‐conservative, that can inform efforts in designing e‐government services. A post hoc analysis confirmed the appropriateness of the market segmentation in understanding citizens’ adoption and use of transactional e‐government services.
Enhancing effects of manufacturing flexibility through operational absorptive capacity and operational ambidexterity
Authors: Patel Pankaj C. , Terjesen Siri , Li Dan
Published: November 2011

A large body of research investigates how manufacturing flexibility in uncertain environments leads to firm performance, with mixed results. The mixed findings could be due to differences across firms in terms of the capabilities to acquire, assimilate, and transform knowledge and to simultaneously pursue both the exploitation of existing operational capabilities and the exploration for new operational capabilities. Building on the literature that suggests that manufacturing flexibility mediates the relationship between environmental uncertainty and firm performance, we explore the applicability of two organizational learning contingencies to the operations environment: operational absorptive capability and operational ambidexterity. Absorptive capacity enables the recognition and assimilation of new knowledge. Ambidexterity determines whether this knowledge will be applied for both exploration and exploitation. Using a sample of 852 manufacturing firms, we find that environmental uncertainty affects firm performance directly and indirectly through manufacturing flexibility. Furthermore, both operational absorptive capacity and operational ambidexterity moderate the relationship between environmental uncertainty and manufacturing flexibility and the relationship between manufacturing flexibility and firm performance. Theoretical and practical implications are discussed.
Electoral-system change in Latvia and the elections of 2010
Authors: Millard Frances
Published: November 2011

Latvia’s highly distinctive proportional electoral system owes its origins to Latvia’s 1922 Constitution and the new democracy’s electoral legislation of 1919 and 1922. Latvia’s unique feature lies in its preference system, offering the voters the opportunity to judge each candidate on their party’s list. Although the system appears to maximise responsiveness to voters’ preferences, in practice this promise remained unfulfilled and the representative quality of parliament was questionable. This was in large measure because of the capacity of candidates to stand in multiple constituencies. In 2009 amendments to the electoral law altered this key provision. This change clearly made a difference, but it could not resolve fundamental problems of Latvia’s political process in general and its political parties in particular.
Rayleigh–Taylor mixing in an otherwise stable stratification
Authors: Lawrie Andrew G. W. , Dalziel Stuart B.
Published: November 2011

We seek to understand the distribution of irreversible energy conversions (mixing efficiency) between quiescent initial and final states in a miscible Rayleigh–Taylor driven system. The configuration we examine is a Rayleigh–Taylor unstable interface sitting between stably stratified layers with linear density profiles above and below. Our experiments in brine solution measure vertical profiles of density before and after the unstable interface is allowed to relax to a stable state. Our analysis suggests that less than half the initially available energy is irreversibly released as heat due to viscous dissipation, while more than half irreversibly changes the probability density function of the density field by scalar diffusion and therefore remains as potential energy, but in a less useful form. While similar distributions are observed in Rayleigh–Taylor driven mixing flows between homogeneous layers, our new configuration admits energetically consistent end-state density profiles that span all possible mixing efficiencies, ranging from all available energy being expended as dissipation, to none. We present experiments that show that the fluid relaxes to a state with a significantly lower mixing efficiency than the value for ideal mixing in this configuration, and deduce that this mixing efficiency more accurately characterizes Rayleigh–Taylor driven mixing than previous measurements. We argue that the physical mechanisms intrinsic to Rayleigh–Taylor instability are optimal conditions for mixing, and speculate that we have observed an upper bound to fluid mixing in general.
Global stability of the two-dimensional flow over a backward-facing step
Authors: Lanzerstorfer Daniel , Kuhlmann Hendrik C.
Published: November 2011

The two-dimensional, incompressible flow over a backward-facing step is considered for a systematic variation of the geometry covering expansion ratios (step to outlet height) from 0.25 to 0.975. A global temporal linear stability analysis shows that the basic flow becomes unstable to different three-dimensional modes depending on the expansion ratio. All critical modes are essentially confined to the region behind the step extending downstream up to the reattachment point of the separated eddy. An energy-transfer analysis is applied to understand the physical nature of the instabilities. If scaled appropriately, the critical Reynolds number approaches a finite asymptotic value for very large step heights. In that case centrifugal forces destabilize the flow with respect to an oscillatory critical mode. For moderately large expansion ratios an elliptical instability mechanism is identified. If the step height is further decreased the critical mode changes from oscillatory to stationary. In addition to the elliptical mechanism, the strong shear in the layer emanating from the sharp corner of the step supports the amplification process of the critical mode. For very small step heights the basic state becomes unstable due to the lift-up mechanism, which feeds back on itself via the recirculating eddy behind the step, resulting in a steady critical mode comprising pronounced slow and fast streaks.
Sr–Nd isotopic characteristics of the Late Cretaceous Shuangyashan suite: evidence for enriched mantle 2 in Northeast China
Authors: ZHANG LEI , HAN BAO-FU , CHEN JIA-FU , XU ZHAO
Published: November 2011

In Northeast China, large volumes of Mesozoic–Cenozoic igneous rocks have developed as a result of long-lasting subduction of the palaeo-Pacific and Pacific plates beneath the eastern Eurasian continent. Previous studies have convincingly confirmed the presence of depleted mantle (DM), FOcal ZOne (FOZO) mantle and enriched mantle 1 (EM1) end-members; the enriched mantle 2 (EM2) end-member is probably present but it has been poorly constrained. The Late Cretaceous Shuangyashan suite, comprising a monzogabbro and diorite–porphyrite stocks and their cumulate hornblendite enclaves, from the Shuangyashan coal basin, Northeast China, is characterized by high initial87Sr/86Sr (0.70922–0.71095) and low initial143Nd/144Nd ratios (0.51221–0.51238) at 98 Ma. Their occurrence demonstrates that EM2 is present in the lithospheric mantle of Northeast China and its formation may be related to recycled continental material in a subduction setting.
A prospective study of social difficulties, acculturation and persistent depression in Pakistani women living in the UK
Authors: Chaudhry N. , Husain N. , Tomenson B. , Creed F.
Published: November 2011

Background

The reasons for the high prevalence of depressive disorders in women of Pakistani origin living in the UK are not clear. The aim of this study was to determine the relative importance of life events, chronic social difficulties and acculturation in a population-based sample of British Pakistani women.

Method

A cross-sectional and prospective cohort study of 18- to 65-year-old Pakistani women in UK was carried out. The Schedule for Clinical Assessment in Neuropsychiatry for diagnosis, the Life Events and Difficulties Schedule for social stress and an acculturation questionnaire were used.

Results

Depressive disorder at baseline was associated with older age, social isolation and marked difficulties involving health and close relationships. Depressive disorder at follow-up was associated with severity of depression at baseline, difficulties in close relationships and two aspects of acculturation, especially less acculturation in relation to use of the English language.

Conclusions

Lack of acculturation, especially less familiarity with the English language, is an independent predictor of persistence of depression in Pakistani women in UK. This needs to be taken into consideration when planning treatment, which also needs to address the personal difficulties associated with persistent depression. The implication of this work is that women of Pakistani origin with depression should be encouraged to receive help in the use of English as one part of treatment that may prevent relapse.
Biostratigraphical control of thrust models for the Southern Uplands of Scotland
Authors: Rushton A. W. A. , Stone P. , Hughes R. A.
Published: November 2011

Graptolite biostratigraphy affords a robust and relatively accurate means of correlating Ordovician and Silurian hemipelagite and turbidite sequences and has been used to establish the structural development of the regional thrust belt in the Southern Uplands of Scotland. The overall structural pattern has long been recognised: greywackes within individual thrust slices, deposited within a relatively short time-interval, become sequentially younger southwards; each overlies the basal Moffat Shale Group which was deposited over a longer time. However, recent refinement of the graptolite biozonal scheme has allowed the better assessment of along-strike variations within the thrust belt which are here illustrated by two transects; one, based on work in the Rhins of Galloway and the Kirkcudbright areas (SW Southern Uplands), and the other in the Peebles-Hawick area (NE Southern Uplands). The SW transect most closely approximates to the regular pattern wherein a southward-propagating thrust-front incorporated sequentially younger greywacke units. The uniform geometry is interrupted only locally, towards the southern margin of the thrust belt, by a system of back-thrusts producing structural pop-ups. The NE transect departs from this regular model: a northern sector shows the orderly initiation of the thrust belt, but towards the SE a more irregular distribution of the thrust-slice agescan be best explained by outof- sequence movement. This transect also shows more repetitive imbrication of the same biostratigraphic interval than is apparent farther SW. In both transects the fundamental changes in thrustbelt geometry took place from mid-Llandovery times onwards, with a reversion to forward-breaking, in-sequence thrusting at the beginning of the Wenlock. The cause is a matter for speculation, but may be linked withthe accommodation of an obstacle to forward-thrust propagation. However it is recognised that such variationsin thrust geometry are a fundamental feature of most thrust belts and do not require a single regionally significant cause.
Silurian and late Ordovician K-bentonites as a record of late Caledonian volcanism in the British Isles
Authors: Fortey N. J. , Merriman R. J. , Huff W. D.
Published: November 2011

Silurian and late Ordovician K-bentonites of the British Isles provide a record of prolonged volcanism during the convergence of terranes associated with closure of the Iapetus and Tornquist Oceans. In the Southern Uplands–Longford-Down and Midland Valley terranes, they range from late Caradoc to Telychian, withfurther early Homerian occurrences. South of the Iapetus suture, in Eastern Avalonia, the range is Hirnantianto early Ludlow in northern England and early Telychian to earliest Ludfordian in the Welsh Borderland and English Midlands. In both cases, the distributions indicate that volcanism was more long-lived and probably more extensive than is depicted in current plate tectonic reconstructions. Average intervals between K-bentonites are estimated, based on Harland et al. (1990), as: c. 65000 years at Dob's Linn (late Aeronian to early Telychian); c. 39000 years in the Cautley area (Telychian); c. 51000 years in a borehole at Walsall (late Llandovery to Sheinwoodian). Trace element geochemistry suggests mostly subalkaline dacitic to rhyolitic magmas in which LILE-enrichment accompanies variable enrichment in crustally derived elements (Ta, Nb). The geochemistry suggests comparison with continental arc volcanism of ‘withinplate, attenuated lithosphere’ character. Ta–Nb enrichment and an absence of Eu anomalies from REE profiles are consistently present northof the Iapetus suture, but trace element patterns are less consistent south of the suture where negative Eu anomalies are generally present. Discriminant function analysis successfully distinguishes Llandovery, Wenlockand Ludlow K-bentonites from south of the Iapetus suture, and Llandovery K-bentonites from north and south ofthe suture. Those from north of the Iapetus suture probably originated in volcanism along the southern marginof Laurentia before final closure of the Iapetus Ocean. Those from south of the suture may have been derived from volcanism associated with late destruction of Iapetus and Tornquist oceanic crust, although an alternative involving volcanism at the southern margin of Eastern Avalonia or Baltica may accord better with the distribution of K-bentonites and the geographical trend of the fragmentary outcrops of Silurian volcanic rocks from southern Ireland to Belgium.
Carboniferous biostratigraphy of the Rookhope Borehole, Co. Durham
Authors: Johnson G. A. L. , Nudds J. R.
Published: November 2011

A deep borehole drilled at Rookhope in Weardale, Co. Durham in 1960–61 proved the Weardale Granite below Carboniferous sediments at a depth of 390 m; an account of the Carboniferous rocks is presented. The boring commenced in the basal Namurian Great Limestone and entered the Dinantian at the bottom of the limestone at 25 m. Most of the ten Brigantian cyclothems sectioned in the borehole are compound and average 30 m thick. They consist of an initial cycle often more than 20 m thick and overlying minor cycles that are usuallyless than 6 m thick. Each of the cycles, both initial and minor, are coarsening upwards sequences from marine limestone or mudstohe to deltaic and fluvial mudstone, sandstone, seatearth and occasionally a thin coal seam. The underlying Asbian consists of seven cyclothems averaging 8 m thick. By contrast they are simple coarsening upwards sequences similar to the Brigantian initial cycles, but no minor cycles are developed.

Marine fossils are abundant in the majority of cyclothems and are listed against their stratigraphical horizon in the borehole. Special studies of miospores, conodonts and foraminiferans from the borehole are presented. A consensus of biostratigraphical evidence shows that the base of the Carboniferous succession in the borehole is of early Asbian age.
Lower jaws, lower tetrapods–a review based on the Devonian genusAcanthostega
Authors: Ahlberg Per Erik , Clack Jennifer A.
Published: November 2011

The lower jaw of the Devonian tetrapodAcanthostegais described for the first time. Redescriptions are provided for the lower jaws of the elpistostegidPanderichthys, the Devonian tetrapodsElginerpeton, Obruchevichthys, Metaxygnathus, VentastegaandIchthyostega, and the Carboniferous tetrapodsCrassigyrinus, MegalocephalusandGephyrostegus. The character distri- butions thus revealed differ considerably from previous accounts, particularly in the wide distribution of certain primitive characters. Meckelian ossification in the middle part of the jaw is widespread among Devonian tetrapods, being demonstrably absent only inAcanthostega.Among Carboniferous tetrapods, a tooth-bearing parasymphysial plate is shown to be present inCrassigyrinusandMegalocephalus(having already been demonstrated by other authors inWhatcheeriaandGreererpeton).A phylogenetic analysis of 26 early tetrapods including all the aforementioned genera, scored for 51 lower jaw characters, produces at least 2,500 equally parsimonious trees. However, the lack of resolution lies largely in a big top end polychotomy containing anthracosaurs, temnospondyls, seymouriamorphs, microsaurs and a nectridean-amniote clade. Below this polycho- tomy, which may correspond approximately to the tetrapod crown group, there is a well-resolved stem-group containing, in descending order,Megalocephalus, Greererpeton, Crassigyrinus, (jaws associated with)Tulerpeton, Whatcheeria, Acanthostega, Metaxygnathus, Ichthyostega, VentastegaandMetaxygnathus(unresolved), anElginerpeton-Obruchevichthysclade, andPanderichthys.This conflicts with recently published phylogenies by Coates and Lebedev & Coates, which placeTulerpetonand all post-Devonian tetrapods in the amphibian or amniote branches of the tetrapod crown group.
Relative sea-level rise during the Main Postglacial Transgression in NE Scotland, U.K.
Authors: Smith D. E. , Firth C. R. , Brooks C. L. , Robinson M. , Collins P. E. F.
Published: November 2011

Flandrian (Holocene) relative sea level changes in the lower Ythan valley, NE Scotland, U.K., are inferred from detailed stratigraphical evidence including microfossil analysis and radiocarbon assay. The principal event recorded is the Main Postglacial Transgression, which was under way in the area byc.8300 and had culminated beforec.4000 radiocarbon years BP. It is concluded that the rise in relative sea levels during the transgression in the area exceeded 12 m; that the mean rate of rise there was 8·05 mm a−1betweenc.8300 andc.7100 radiocarbon years BP, or 7·09 mm a−1based upon calibrated dates for the same period, before declining markedly to 1·75 mm a−1(radiocarbon) or 1·86 mm a−1(calibrated) to the culmination of the event. By comparison with other sites, the culmination appears to have been time-transgressive in eastern Scotland. Deposits of the Second Storegga Slide tsunami, which occurred during the Main Postglacial Transgression, are present in the Ythan valley, where the sediment run-up of the event at the sites studied is estimated to have been within the range 2·99–5·19 m.
Trilobites and biofacies of the Ordovician Pagoda Formation, Donggongsi of Zunyi, Guizhou Province, China
Authors: Yin Gongzheng , Tripp Ronald P. , Zhou Zhiyi , Zhou Zhiqiang , Yuan Wenwei
Published: November 2011

Twenty-one trilobite species belonging to 18 genera are described from the measured section of the Pagoda Formation (Caradoc) at Donggongsi, Zunyi, Guizhou Province, China. The fauna is numerically dominated by the hammatocnemidOvalocephalusand remopleurididDislobosaspis(gen. nov.), and theOvalocephalus–DislobosaspisBiofacies is established to represent a shallow outer-shelf trilobite association. The lithofacies and trilobite taphonomy indicate a comparatively quiet and undisturbed depositional environment. Trilobites exhibit strong SE Asian affinities and formed part of the Peri-Gondwana fauna. They are closely related to those of South- Central Europe but show some Baltoscandian aspects.
Grenvillian magmatism of western and central Nordaustlandet, northeastern Svalbard
Authors: Johansson Åke , Larionov Alexander N. , Tebenkov Alexander M. , Gee David G. , Whitehouse Martin J. , Vestin Jessica
Published: November 2011

The basement of the island of Nordaustlandet, northeastern Svalbard, consists of a complex of metasedimentary and metavolcanic rocks, granites and augen gneisses, unconformably overlain by the Neoproterozoic Murchisonfjorden Supergroup. Earlier U-Pb dating of the Laponiafjellet and Kontaktberget granites has shown them to be late Grenvillian, with ages of c. 960 Ma and 940 Ma, respectively. Here, we present conventional U-Pb zircon and monazite data, single zircon Pb-evaporation data and ion microprobe data from the Kapp Hansteen Group and Svartrabbane Formation volcanic and subvolcanic rocks, and from the Fonndalen and Ringåsvatnet augen gneisses of central Nordaustlandet. The combined evidence suggests late Grenvillian magmatic ages of 940–970 Ma for all these rocks, with inherited zircons ranging in age from c. 1200 Ma to 2600 Ma. The investigated rocks vary in chemical composition from andesites to rhyolites and granites, and show generally similar trace and rare earth element patterns, with trace element compositions suggesting a volcanic arc or syn-collisional tectonic setting, and major element compositions suggesting a large sedimentary input to the magmas. Contributions from older crustal material are also supported by Nd isotope data and the presence of inherited zircons.

The Grenvillian magmatic rocks thus originated in a series of magmatic events along a continental margin over a time span not longer than 30 Ma. The volcanic rocks were extruded onto folded strata of the Brennevinsfjorden Group–Helvetesflya Formation, which must have been deposited in the time interval 1200–960 Ma. Folding of the metasediments preceded the volcanism, but was synchronous with intrusion of the augen gneiss protolith, and was followed by crustal stabilisation, uplift and erosion. This newly formed Grenvillian crust then served as basement for the deposition of the Neoproterozoic Murchisonfjorden Supergroup. The present outcrop pattern of the Grenvillian rocks is largely the result of large-scale Caledonian folding and doming.
Microdecemplicida, a new order of minute arthropleurideans (Arthropoda: Myriapoda) from the Devonian of New York State, U.S.A.
Authors: Wilson Heather M. , Shear William A.
Published: November 2011

Microdecemplex rolfei, gen. and sp. nov., a new microarthropleuridean less than 5 mm long, is described from the Middle Devonian Panther Mountain Formation of New York State, U.S.A. The specimens consist of organically preserved cuticle, with some preserving the only cephalic structures known for arthropleurideans. A new order, Microdecemplicida, and a new family, Microdecemplicidae, are established. The probable phylogenetic position of the Microdecemplicida as one of the basal clades of Diplopoda is proposed.
Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland
Authors: Macdonald R. , Gottfried D. , Farrington M. J. , Brown F. W. , Skinner N. G.
Published: November 2011

The late Carboniferous quartz dolerite suite of Scotland consists mainly of quartz tholeiites, with subordinate olivine tholeiites and tholeiitic andesites. The low pressure evolution of the magmas was controlled by fractionation of olivine–plagioclase–pyroxene–oxides assemblages from more magnesian compositions and plagioclase–pyroxene–oxides–apatite removal from intermediate compositions. A higher pressure stage dominated by olivine fractionation is suggested by the presence of olivine nodules in a magnesian basalt dyke from Fife.

The suite is of high-Fe-Ti type, closely comparable to certain basalts erupted in areas of active lithospheric spreading or “hot spots”, such as Iceland and Hawaii. The ppO2 can be inferred to have been rather higher in the Scottish rocks than in comparative suites, promoting earlier separation of Fe-Ti oxides, with the consequent effects on trace element distribution.

Apart from varying degrees of fractionation, chemical variations in the dykes are of three types: rather minor variations along individual dykes, variations across certain thicker dykes, and minor and trace element variations reflecting chemical heterogeneities in the mantle sources. The dykes and sills are inferred to have been fed from a plexus of small, partly independent, magma reservoirs.

New trace element data on tholeiitic lavas from the Oslo Rift confirm recently revived suggestions that the Scottish and northern English quartz dolerites are part of a larger province extending into Scandinavia.
Structural, metamorphic and igneous history of migmatites in the deep levels of a wrench fault regime, Savonranta, eastern Finland
Authors: Halden N. M.
Published: November 2011

The migmatite complex of the Savonranta district of eastern Finland represents the combined effects of polyphase deformation, polymetamorphism and the emplacement of a series of dioritic, grandioritic, granitic and pegmatitic masses. The most significant feature in terms of both regional structure and control of neosome emplacement is a large wrench fault zone along which there has been a minimum of 30 km displacement. Its development was controlled by a stress system related to plate movement in the early-middle Proterozoic Svecokarelian orogenic belt.

Successive neosome development has been related to the extensive structural and metamorphic history of the amphibolite facies palaeosome mica schists which has been deduced from refolding and cross-cutting relationships. Rb–Sr whole-rock isotopic studies of a porphyritic granite, whose emplacement was controlled by the wrench fault regime, indicate an age of crystallisation of 1786 ± 80 m.y. The initial 87Sr/86Sr ratio of 0·7053 ± 01 shows the source region for the granite magma had a previous crustal history.
Glacier flow at a former ice-divide in SW Scotland
Authors: Cornish Roger
Published: November 2011

Late Devensian ice-sheet movement in the western Southern Uplands of Scotland is demonstrated by the distribution of erratics from four different bedrock sources and by glacial striae and ice-moulded landforms. This evidence shows an almost radial movement of ice from an ice-divide zone. The control of relief over ice flow and the distribution of erratics is emphasised. The distribution of erratics from two of the sources, however, shows that debris in the ice was transported only a very short distance in certain places. Abundant deposits of lodgement till occur in the vicinity of the former ice-divide. Although it is generally considered that glacial erosion, and therefore deposition, are insignificant at the centre of ice-sheets, this study suggests otherwise. It is inferred that till and erratics may be emplaced during ice-sheet build-up when conditions for erosion obtained, these deposits being protected from subsequent removal by the establishment of an ice-divide across the area. The implications for high rates of erosion in ice-sheet source areas are examined.
The Upper Cambrian bradoriid ostracod Cyclotron lapworthi is a hesslandonid
Authors: Williams Mark , Siveter David J. , Rushton Adrian W. A. , Berg-Madsen Vivianne
Published: November 2011

Cyclotron lapworthi (Groom, 1902), one of the few British Cambrian bradoriid ostracod species known from a large number of specimens, is redescribed. It has an interdorsum, thus indicating a hesslandonid affinity. The ontogeny of C. lapworthi does not demonstrate a clear distinction of its individual moult stages but does show marked changes in the development of nodes and lobes. C. lapworthi shows wide variation in carapace shape possibly indicating that its valves were thin and relatively flexible. In England and Canada C. lapworthi is restricted to the Upper Cambrian Olenus Zone. C. lapworthi may also occur coevally in the Upper Cambrian of Sweden.
Evidence for a Caledonian orogeny in Poland
Authors: Johnston J. D. , Tait J. A. , Oliver G. J. H. , Murphy F. C.
Published: November 2011

The Lower Palaeozoic tectonic history of central and eastern Europe is poorly understood because of extensive Variscan and/or Alpine reworking. The trace of the Tornquist Sea, the SE arm of the Lower Palaeozoic Iapetus Ocean, extended from NE Britain to Asia Minor. The site of this ocean is constrained by the tectonostratigraphy and faunal provinciality of Lower Palaeozoic inliers in northern Czechoslovakia, and southern Poland. In this paper, the collage of contrasting tectonostratigraphic histories of terranes in the Lower Palaeozoic of Poland is reviewed. Fossil evidence demonstrates that the Holy Cross Mountains and the Krakovian Belt display Lower Ordovician and Lower Devonian angular unconformities. Faunal data suggest that the Tornquist Suture Zone must lie south of the Holy Cross and between Upper Silesia and the Barrandian of the Czech Republic. Between these areas, in the Sudeten Mountains, a continental scale sinistral mylonite zone (along the line of the Intra-Sudetic Fault) was periodically active between the Middle Ordovician and the Upper Triassic. Various dismembered ophiolite, island arc and batholith terranes from alongside the Intra-Sudetic Fault have Ordocivian and Silurian magmatic and metamorphic zircon isotopic and fossil ages. Thus the often stated view that deformation in the Sudetes is Variscan (i.e. post-Middle Devonian) must be called into question. It is proposed instead that the Tornquist Suture is located within the Sudeten mountains, and as in the Holy Cross Mountains, much of the observed deformation is post-Cambrian and pre-Gedinnian in age, i.e. Caledonian.
The postcranial skeleton of the Middle Devonian lungfishDipterus valenciennesi
Authors: Ahlberg Per Erik , Trewin Nigel H.
Published: November 2011

The axial skeleton and fin supports of the Middle Devonian lungfishDipterusare described from a range of specimens from the Orcadian Basin of Scotland. The axial skeleton of the trunk region consists of intercentra, relatively short ribs, and neural arches bearing two rows of supraneural spines; posteriorly, the intercentra are replaced by haemal arches. The notochord seems to have been essentially unconstricted. There may have been two pairs of cranial ribs. In general terms the vertebral column resembles that ofNeoceratodusbut is more fully ossified. The only known paired fin support ofDipterusis an archipterygial structure resembling those ofNeoceratodus, with at least seven mesomeres and jointed pre- and postaxial radials. The pectoral fin is rotated as in modern lungfishes. The median fin supports all consist of basal plates supporting radials. In the posterior dorsal fin support the posterior radials form a branched structure. The heterocercal tail is supported by segmental radials. A new body reconstruction is presented.

The characters possessed byDipterusoffer support for a lungfish–porolepiform sistergroup relationship. All known lungfishes fit into a single cumulative series of postcranial morphologies. The evidence for a paedomorphic trend in lungfish phylogeny is interesting but inconclusive.
Conodont Colour Alteration Index (CAI) values for the Carboniferous of Scotland
Authors: Dean Mark T. , Turner Nicholas
Published: November 2011

Conodont elements from Scottish Carboniferous rocks have been reviewed for Colour Alteration Index(CAI) data, and most values range between 1 and 1·5. Assuming a local average geothermal gradient similar to that of today, the observed and predicted CAI values generally fit well. Only a few of the samples analysed were influenced by local igneous intrusives. The CAI range shown lies within the immature (early dry gas) to mature (perhapsmid-oil window) stages of hydrocarbon generation, and this suggests that burial maturation (where CAI values are 1-5) could account for locally generated oil, where this occurred away from igneous intrusions. Alkali-dolerite and tholeiitic intrusives are, however, widespread in the Midland Valley of Scotland, and an understanding of their thermal effects has implications for both coal and petroleum exploration. The insensitivity of conodonts to low temperatures is noted, and the relevance, application and potential of various other palaeothermometers is discussed. Locally, the qualitative study of spore colour (SCI) appears useful.
Ontogeny of the Carboniferous trilobitePaladin eichwaldi shunnerensis(King 1914)
Authors: Clarkson Euan N. K. , Xi-guang Zhang
Published: November 2011

The Carboniferous trilobitePaladin eichwaldi shunnerensis(King 1914), at its type locality in northern England is exceptionally well-preserved, and shows all stages of growth from the degree 0 meraspis onwards. The post-protaspid ontogenyis described here with particular reference to the development of cuticular sculpture. On the dorsal surface of the smallest specimens a polygonal network of raised ridges (cell polygons) is apparent. With size increase, granules progressively appear amongst the polygons, which in turn change into large tubercles as the polygonal network fades. As the trilobite grows into an adult, the tubercles become relatively smaller, and pits, the openings of cuticular canals, appear amongst them. Marginal terrace lines become pronounced. On the hypostome, however, terrace lines become effaced centrally, while large pits develop. In the early meraspis the eyes are “schizochroal”, but the lenses rapidly become closely packed and contiguous and the eye is soon of “holochroal” type. The meraspid phase is passed through very rapidly. Whereas the earlymeraspis could not enroll, its pygidium could be bent down vertically, and this facility might have allowed the larva an escape reaction.
Biostratigraphy of late Llandovery (Telychian) and Wenlock turbiditic sequences in the SW Southern Uplands, Scotland
Authors: White Dennis E. , Barron Hugh F. , Barnes Robert P. , Lintern Byron C.
Published: November 2011

In the SW part of the Southern Uplands of Scotland the relatively thin Moffat Shale Group (late Ordovician–early Silurian) is succeeded by a thick development of Silurian greywackes, of variable turbiditic facies. This includes late Llandovery (Telychian) quartzose greywackes with interbedded thin graptolitic shales of theturriculatusandcrispusbiozones, in the upper part of the Gala Group, a sequencewhich is laterally equivalent to the basal part of the Hawick Group. The age of the finer-grained calcareous Hawick Group, which here includes 1. the Ross Formation, ranges from late Llandovery (turriculatusBiozone) to early Wenlock (riccartonensisBiozone). The Riccarton Group, which contains thick units of thinly-bedded siltstones and mudstones, is of Wenlock age (riccartonensistolundgrenibiozones). Within this sequence, all the biozones of the standard graptolite zonal scheme have been recognised in the area, with the exception of thecrenulataBiozone of the late Llandovery (Telychian Stage) and themurchisoniandellesaebiozones of the Wenlock (Sheinwoodian Stage). Details of the graptolite biostratigraphy areclosely comparable with those of the markedly thinner sequences of northern England. Acritarchs occur throughout the sequence but are most numerous and best preserved in the Gala Group. Poorly preserved chitinozoa and spores are also present, the former occurring sporadically throughout the succession but the latter become common only in the Riccarton Group.
The first zosterophyll from the Lower Devonian Rhynie Chert, Aberdeenshire
Authors: Lyon A. G. , Edwards Dianne
Published: November 2011

Fragmentary remains of a vascular sporophyte from the Rhynie Chert are described as a new genus and species, Trichopherophyton teuchansii. The plant, which is characterised by the possession of unicellular spinous hairs, exarch xylem and laterally attached, marginally dehiscent sporangia, is assigned to the Zosterophyllophytina, but lack of information on the arrangement of sporangia prevents its more precise positioning within the subdivision. Unusual features include the combination of circinate tips to axes with almost terete xylem strands, and the lack of a thick-walled outer cortical zone. Associated axes, lacking spinous hairs, but having papillate or rhizoid-like epidermal emergences, are interpreted as likely rhizomes of Trichopherophyton. Features, such as unicellular spinous hairs, rhizoid-like emergences, circinate tipsand parenchymatous cortex are considered in relation to the functioning and growth of aplant inhabiting an early Devonian wetland.
Revision and subdivision of the polyphyletic ‘Leonaspis’ (Trilobita)
Authors: Ramsköld Lars , Chatterton Brian D. E.
Published: November 2011

A phylogenetic analysis is performed on all species previously assigned to the odontopleurid trilobite genusLeonaspis. The PAUP analysis shows this genus, as conventionally defined, to be polyphyletic, composed of four groups of equal taxonomie rank.Leonaspis(s.s.) is here restricted to one of these groups only, a monophyletic set of species characterised by ‘four-spined’ pygidia (i.e. with four spines between the major border spines) and a thorax of nine segments.Kettneraspisis recognised for the largest of these four groups, and is composed of ‘two-spined’ species with nine thoracic segments.LeonaspisandKettneraspisbelong to the Odontopleurinae. A third group of previous ‘Leonaspis’ species constitute a new genus of the Acidaspidinae. Its species are characterised by being ‘four-spined’ and having ten thoracic segments. For these the new genusExallaspisis erected, with type speciesE. bufo. A fourth group of ‘Leonaspis’ species, being ‘four-spined’ with nine thoracic segments, belongs toEoleonaspis, an Ordovician odontopleurine genus.LeonaspisandExallaspisare temporally and spatially non-overlapping,Leonaspisbeing exclusively Gondwanan post-Wenlock, whereasExallaspisis restricted to areas north of the Rheic Ocean and ranges from basal Llandovery to Ludlow.Kettneraspisis pandemic. The condition of five epiborder spines and ten border spines on the free cheek is proposed as plesiomorphic for odontopleurids, and the border spines are shown to originate as two separate rows with alternating spines. A shift in position of the facial suture is shown to transfer the genal spine from the cranidium to the free cheek inKettneraspismeraspides of degree 1 or 2, and the previously suggested co-occurrence of a fixigenal and librigenal spine in these stages is refuted. Earlier proposed dimorphism is rejected, and two mechanisms for reduction in the number of pygidial border spines are proposed.Kettneraspis reetaesp. nov. is described.
Evolution of Ordovician terranes in western Ireland and their possible Scottish equivalents
Authors: Williams D. M.
Published: November 2011

In the W of Ireland the Ordovician rocks of South Mayo and Clew Bay are now juxtaposed but a comparison of the sedimentary histories of these two sequences shows that they accumulated in basins which were probably separated during most of their history. The large amount of terrigenous detritus present in the Arenig to Llanvirn elements of the South Mayo succession is not manifest in that of Clew Bay until the Llandeilo/Caradoc, by which time sedimentation in South Mayo had ceased. A comparison of the South Mayo Ordovician with that of Girvan in Scotland demonstrates that both sequences had a similar provenance. This source contained an ophiolite, granites and some (probably pre-Dalradian) metamorphic rocks. Sediment dispersal directions for the two sequences are opposite in sense, being primarily northward in South Mayo and southward at Girvan. The two stratigraphies indicate that basement subsidence behaviour in South Mayo was virtually the opposite of that at Girvan where initial shallow water sedimentation was rapidly succeeded by deep water environments at the end of the Llanvirn. The two basins may thus have been marginal to a single Ordovician arc complex. One reason for the opposite sense of basin subsidence may lie in the suggested reversal of subduction polarity during the Ordovician. In this scenario the South Mayo basin may be envisaged as lying to the N of a northward-facing arc during the early Ordovician. A new, northward, subduction direction instigated during the Llanvirn, resulted in a fore-arc basin at Girvan complemented by a closing back-arc basin in South Mayo.
The structure and petrogenesis of the Trallval and Ruinsival areas of the Rhum ultrabasic complex
Authors: Volker J. A. , Upton B. G. J.
Published: November 2011

Detailed mapping of the Trallval-Ruinsival area of the ultrabasic complex of Rhum has revealed the relationship between the intrusive peridotites, which form a major part of the complex, and the layered ultrabasic rocks. The layered rocks on Trallval are correlated with Units 8 to 15 of the Eastern Layered Series as seen on Hallival and Askival, and part of an additional unit, Unit 16, has also been identified. The layered rocks of Ruinsival and the western part of Trallval form part of the Central Series and have been subdivided into six cyclic units. They are associated with four sets of intrusive breccia zones which converge towards a central region. Four cylindrical plugs of intrusive peridotite occur within the area of outcrop of the Central Series. Criteria are listed for the distinction of intrusive peridotite from conformable peridotites formed in situ. Distinctive textures and structures are described; these include vertical feldspathic streamers, which are interpreted as direct evidence for the upward expulsion of interstitial fluid, and loading structures at the contact between a peridotite layer and underlying allivalite are ascribed to the intrusion of a peridotite sill. A comparison of the Eastern Layered Series and the Central Series suggests that three stages were involved in the formation of the ultrabasic rocks: (i) the accretion of rhythmically layered unconsolidated olivine cumulates; (ii) the upward expulsion of intercumulus liquid; and (iii) the formation of either allivalite (as in the Eastern Layered Series) or ultrabasic breccia zones (as in the Central Series) from the expelled intercumulus liquid, depending on whether the tectonic environment was quiescent or extensional.
Glacial and volcanic geomorphology of the Chimborazo-Carihuairazo Massif, Ecuadorian Andes
Authors: Clapperton Chalmers M.
Published: November 2011

The Chimborazo (6,310 m)–Carihuairazo (5,102 m) massif is one of the largest ice-capped central volcanic complexes in the northern Andes. Combined evidence from volcanic and glacial landforms and sediments suggests cyclical evolution during the Pleistocene. Effusive eruptions of mixed high-silica andesite (SiO2%wt c. 60) predominated and built the bulk of the edifice. Explosive activity developed as the parental magma evolved to dacite-rhyolite (SiO2%wt 64–74), culminating with cone collapse and large-scale debris avalanching. Post-collapse activity evolved from the production of high-silica andesite to terminate with monogenetic eruptions of basic andesite (SiO2%wt 54–56) from flank fissures. The last eruption occurred before 11,000 yBP.

The interstratification of volcanic and glacial deposits shows that glaciers expanded and contracted several times during the later Pleistocene, while the volcanic edifices were evolving. Glaciers expanded to altitudinal limits of 3,400–3,600 m during the early last glaciation and reached similar limits sometime after 33,000 yBP; an intervening interstadial interval lasted for 10,000 y. By 20,000–18,000 yBP, glaciers receded slightly because of decreased precipitation, but later readvances culiminated at 12,000–10,000 yBP and during the last 5,000 y. Glacier reconstruction and estimation of former equilibrium line altitudes suggest that the mean annual temperatures during the full glacial, late-glacial and Neoglaciation intervals were lower than now by c. 5–6°C, 2–3°C and 1°C, respectively, but these may be underestimates because of the assumption that precipitation was constant.
Reply to ‘The Torridonian Stac Fada Member: a discussion’
Authors: Sanders I. S. , Johnston J. D.
Published: November 2011

We welcome the views of A. D. Stewart (1990) on our interpretation of the unusual lithology and contact relations of the Stac Fada Member at Stoer. Stewart contends that our lower breccia body is a down-faulted outlier of the main breccia body and is therefore not a feeder. He thus rejects our notion that the Member is a peperitic extrusion: he also rejects the previously published view that the Member is a volcanic mudflow. Instead he suggests that the Stac Fada Member is one of several muddy volcanic horizons in the Stoer Group, all of which underwent post-depositional disturbance.
Wenlock (Silurian) graptolites, Cape Phillips Formation, Canadian Arctic Islands
Authors: Lenz A. C. , Melchin M. J.
Published: November 2011

Twenty six of the more important species of monograptids (s.l.), retiolitids andCyrtograptus(from a total fauna of 52 species) are described from Wenlock strata of the Cape Phillips Formation, Canadian Arctic Archipelago. Of this fauna, eight new species or subspecies,Monograptus firmus festinolatus, M. instrenuus, M. opimus, M. testis incomptus, Cyrtograptus falcatus, C. hamatus brevis, C. kolobusandC. pseudomancki, are described and illustrated.

Wenlock biostratigraphic zones comprise theCyrtograptus centrifugus-C. insectusZone (earliest Wenlock),M. instrenuus-C. kolobusZone, tentatively divisible into lower and upper subzones,C. perneri-M. opimusZone possibly divisible into lower and upper subzones, C.lundgreni-M. testisZone divisible into a lowerM. testis incomptusSubzone and an upperM. testis testisSubzone, and thePristiograptus ludensisZone (latest Wenlock).