bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of sediment supply in controlling alluvial architecture: an example from the Spanish Pyrenees
Authors: VINCENT STEPHEN J.
Published: December 2007

This study isolates the controls on the alluvial architecture of two interfingering late Lutetian fluvial systems preserved at the northern margin of the Tremp-Graus Basin, in the south central Pyrenees. One of these, a northerly, mountain-belt-derived, high-gradient, bedload-dominated gravelly system, displays marked variations in its alluvial architecture, with systematic changes in the width, depth, internal facies arrangement and stacking pattern of its channel bodies. The other, an easterly, basin-axis-derived, lower gradient, poorly drained alluvial system, displays no discernible systematic variations in alluvial architecture.

A common control that would similarly affect both of the interfingering fluvial systems cannot be responsible for their contrasting architectural patterns. Variations in base level, despite the contemporaneous shoreline being only 18 km downstream, climate, or the tectonic rotation of the study area are therefore discounted. Fluctuations in sediment supply to the northerly derived system resulting from the episodic uplift of its drainage basin are instead proposed, although intrinsic controls cannot be totally discounted. Similar sediment flux variations in the headwaters of the easterly derived system are envisaged, but its longer, lower-gradient transport path was effective in dampening out these fluctuations upstream of the study area.
Climatic and tectonic controls on fluvial incision and aggradation in the Spanish Pyrenees
Authors: JONES STUART J. , FROSTICK LYNNE E. , ASTIN TIMOTHY R.
Published: December 2007

The influences of tectonic and climatic changes on upland river systems are investigated using data from Plio-Pleistocene terraces of the Rio Cinca river in the southern Pyrenees. This river runs transverse to the main thrust fault structures and is a major conduit for sediment delivery to the Ebro Basin. Detailed field mapping, combined with long-profile and palaeohydraulic reconstructions, yields a comprehensive picture of changes in palaeoriver character during the Plio-Pleistocene. As the area is over 150 km from the basin outlet in the Mediterranean Sea, changes in base level are unlikely to have influenced terrace development. Although tectonic activity has exerted a strong control on the position of the river, the main period of thrust propagation pre-dates the terraces and activity has waned from the Pliocene through to the present. It is concluded that the main control on incision in this area is climate, through its influence on sediment supply. Rivers which are starved of sediment by climate change will have the power to incise, whereas aggradational phases are linked to periods of increased sediment flux.
Volcanic rocks as discriminants in evaluating tectonic versus climatic control on depositional sequences, Permo-Carboniferous continental Saar-Nahe Basin
Authors: STOLLHOFEN HARALD , FROMMHERZ BERND , STANISTREET IAN G.
Published: December 2007

The third- and fourth-order sequential arrangement of continental sedimentary strata in the Permo-Carboniferous Saar–Nahe Basin preserves a detailed record of contemporaneous faulting and volcanism. Transgressive lacustrine facies of the Upper Carboniferous coincide with the stratigraphic position of extrabasinally derived pyroclastic fallout layers and features of synsedimentary tectonism such as unconformities, thickness and facies changes across faults, and seismogenic deformation structures. The tectonic imprint on fourth-order cycle initiation is further documented by abrupt vertical facies transitions during lake transgression, implying rapid and episodic rather than gradual basin subsidence. This interaction becomes much more pronounced within the fluvially dominated Lower Permian, when tectonism controlled both the ascent of large volumes of magma within the basin as well as episodic enlargement of accommodation space and depositional area. Major extrusive volcanic units are preferentially associated with sequences recording transgression that are only preserved in fault-bounded hanging wall traps starved from clastic sediment input. It is suggested that the stratigraphic position of pyroclastic fallout within the sequential framework of basins elsewhere, provides an important analytical tool for the identification of contemporaneous tectonic events and as such form a discriminant between purely climatically induced Milankovitch band cycles versus those involving a tectonic control.
The late Miocene climate of northeastern Africa: unravelling the signals in the sedimentary succession
Authors: GRIFFIN DAVID L.
Published: December 2007

Examination of the depositional profile of the Miocene/Plio-Pleistocene succession at two locations in the Gulf of Suez and seven locations in the Red Sea leads to the conclusion that the Messinian (Zeit Formation and equivalent) sedimentary rocks were deposited at a rate greater than other units of the Miocene/Plio-Pleistocene in these areas. The Zeit Formation contains a significantly higher clastic content than the underlying South Gharib Formation. These two aspects of the stratigraphy are taken to indicate that the Messinian was a time of high rainfall and high sediment yield rates. This period, named the Zeit Wet Phase, stands in marked contrast to the arid conditions of the preceding Tortonian Stage. The latter stage is represented in the Gulf of Suez and Red Sea area by the halite-bearing South Gharib Formation and its equivalents.

Physical evidence for a humid Messinian is provided by five lines of evidence involving four sites around the Red Sea and two sites offshore. It is suggested that the Zeit Wet Phase was marked by high monsoonal activity as demonstrated by drilling sites of the Ocean Drilling Program. It is probable that the wet phase peaked in the late Messinian at the time of the low-stand of the Mediterranean during the Messinian Salinity Crisis.
Calibrating the duration and timing of the Messinian salinity crisis in the Mediterranean: linked tectonoclimatic signals in thrust-top basins of Sicily
Authors: BUTLER R. W. H. , McCLELLAND E. , JONES R. E.
Published: December 2007

The Messinian 'salinity crisis' which affected the Mediterranean represents one of the most dramatic examples of base-level fluctuation known in the geological record: an amplitude of perhaps 2 km within a stage with a duration of less than 2 Ma. Deposits within the Caltanissetta Basin of central Sicily are used to calibrate the duration and timing of these fluctuations. Two successions of evaporites termed 'First Cycle' and 'Second Cycle', are separated by an inter-regional unconformity. The first cycle is regionally regressive while the second is transgressive. Chronostratigraphic calibration of these deposits has been provided by a linked magnetostratigraphic, structural and sedimentological study. The regression was protracted. The earliest evaporites in our study accumulated early in Chron C3Ar (pre 6.88 Ma) and the youngest accumulated late in chron C3An (post 6.0 Ma). During this interval the basinward shift in coastline was 70 km and in vertical section implies a relative fall in sea level at 0.3–0.4 m ka–
1
Lowstand probably finally occurred at 5.8–5.5 Ma. Transgression, marked by accumulation of the 'second cycle' deposits, which all record reversed magnetizations (C3r), apparently occurred far more rapidly (200 ka), prior to the return to 'normal' marine conditions in the central Mediterranean late in Chron C3r. Local rates of tectonic deformation are relatively slow within the thrust belt which underlies the Caltanissetta Basin. Therefore, it is likely that the timing and rates of the Messinian 'salinity crisis' on Sicily are generally applicable to other basins in the region and help to underpin rates of climate change within this part of the Neogene.
The Mediterranean water body in the late Messinian: interpreting the record from marginal basins on Sicily
Authors: KEOGH S. M. , BUTLER R. W. H.
Published: December 2007

The stratigraphic record of climatic and palaeoceanographic changes in the Mediterranean during the late Messinian is controversial. On Sicily, sedimentary facies show a steady transgression, suggesting that sub-basins were hydrodynamically linked to a larger water body. Here we test this hypothesis using strontium isotope studies from Messinian materials collected from a range of sites in the Caltanissetta Basin of central Sicily. The strata include a regionally regressive ‘First Cycle’ of early-mid-Messinian age and a younger, transgressive ‘Second Cycle’. These cycles are separated by an inter-regional unconformity which may be correlated with base-level low stand in the Mediterranean.
87
Sr/
86
Sr ratios for all First Cycle gypsum fall within the expected global marine composition (0.70891–0.70897). All Second Cycle analyses fall within a grouping of significantly lower values (0.70868–0.70878), a surprisingly tight but discrepant grouping for data collected from shells of a brackish water fauna and from gypsum. Analyses from these different Second Cycle materials are statistically indistinguishable. These results indicate that the strontium isotopic composition of waters from different sub-basins on Sicily are indistinguishable regardless of salinity during the late Messinian. Therefore these basins must have mixed with a larger, homogenized reservoir which we infer was the ancestral Mediterranean. Thus circum-Mediterranean basins may indeed chart regional palaeoceanographic and climatic events. By the end of Messinian times the base-level of the Mediterranean was within the range of the world's oceans but the water-body probably had a distinctly different but internally homogeneous strontium isotopic composition.
Lithofacies and faunal succession (faunal phase analysis) as a tool in unravelling climatic and tectonic signals in marginal basins; Messinian (Miocene), Sicily
Authors: PEDLEY MARTYN , MANISCALCO ROSANNA
Published: December 2007

Many basins are filled under the influence of tectonics and variable climatically driven processes. Unravelling the relative contributions of these is generally easier in fossiliferous sequences if faunal diversity patterns are considered in conjunction with lithofacies analysis. This approach has been successfully applied to Late Miocene strata of Sicily, where progressive restriction and desiccation within the Sicilian Caltanissetta region occurred under a semi-arid climate during the Messinian Stage. This restriction was partly due to Antarctic cooling which produced Palaeo-Mediterranean sea-level oscillations during the Early Messinian, as a prelude to closure of the Atlantic connections. In addition, regions within this Afro-European plate collision zone were also subjected to syndepositional tectonic deformation associated with progressive perched basin development above foreland (south) verging thrust sheets. The relative impacts of climatic (eustatic) versus tectonic control on sedimentation patterns within these perched basins has been debated at length. However, progress towards resolving this problem by a combined approach involving lithofacies analysis, and faunal phase analysis provides clues for separating the effects of the controlling factors. Faunal phase analysis identifies general faunal associations with minimal emphasis on species diversity. The resulting ‘phase’ plots for Early Messinian strata appear to be transgression skewed when controlled by eustatic cyclicity, and regression skewed when driven by regional tectonics associated with perched basin tectonics.
Small and short-lived magma batches at composite volcanoes: time windows at Tongariro volcano, New Zealand
Authors: HOBDEN B.J. , HOUGHTON B.F. , DAVIDSON J.P. , WEAVER S. D.
Published: December 2007

Many are volcanoes are characterized by frequent eruptions of small (<0.1 km
3
) volume. A key question is do such small events represent discrete magma batches or do these magmas share a partial common history and to what depths? The last 1000 years of eruptions at Tongariro volcano, New Zealand, offer a series of time-calibrated 'snap shots' of an are magmatic system. Complex and abrupt changes in magma chemistry at Tongariro attest to the small size (<1 km
3
) and short life span (years to decades) of many magma batches and a powerful role for shallow level assimilation, fractional crystallization and mingling in modifying magma compositions on time scales as short as a year.
Sulphur isotope compositions of sedimentary phosphorites from the basal Cambrian of China: implications for Neoproterozoic-Cambrian biogeochemical cycling
Authors: SHIELDS GRAHAM A. , STRAUSS HARALD , HOWE STEPHEN S. , SIEGMUND HENDRIK
Published: December 2007

The Meishucun Section (Yunnan Province, South China) is considered to be an important Precambrian–Cambrian boundary section, primarily because of its rich small shelly fossil record. In this article, we report the results of a sulphur isotope study of phosphate-bound sulphate from the Meishucun Section and several correlative sections in South China. Forty clastic, granular phosphorites from Meishucun yield tightly grouped δ
34
S values averaging 33‰ (CDT), which agree well with published evaporite data for the lower Cambrian of Siberia and elsewhere. We argue that these strongly positive values reflect the sulphur isotopic composition of ambient seawater, confirming further the existence of uniquely high δ
34
S values in the earliest Cambrian oceans. This novel use of trace-sulphate in phosphate to constrain seawater δ
34
S represents the first time that sulphate δ
34
S data for this period have been given precise biostratigraphic assignments. Superimposed on the overall trend are short-term, stratigraphic variations, which might reflect local variations in the sedimentary and early diagenetic environment. Our data, together with other published data, indicate that seawater sulphate δ
34
S rose from low values (15–20‰) during the pre-750 Ma Proterozoic to possibly all-time high values (>32‰) by the earliest Cambrian. We argue that this rise may, in part, relate to increases in the amount of sulphur isotopic discrimination during microbially mediated sulphate reduction as a result of increased sulphide reoxi-dation. On the other hand, the Neoproterozoic trend to high δ
34
S values appears to mirror a trend to decreasing seawater δ
13
C towards the Proterozoic–Phanerozoic transition, implying progressive increases in the efficiency of organic carbon recycling, which would normally be coupled with real increases in sulphate reduction on the global scale. We consider that both these changes in biogeochemical cycling derive ultimately from the introduction of macrofauna around this time and, in particular, from the influence of bioturbation on early diagenesis. Precise constraints on S-isotopic evolution during the Neoproterozoic require additional trace sulphate studies.
Mid- to late Quaternary environments and stratigraphy of the southern Sierra Leone shelf, West Africa
Authors: PEGLER E. A.
Published: December 2007

The middle to upper Quaternary succession of the southern Sierra Leone shelf appears to have been deposited in response to three glacial sea-level cycles, the last of which has left the most complete sedimentary record. The unconformable base of the succession is deeply incised off larger rivers inshore but has little relief toward the shelf-break. This difference results from the steep gradient of the inner shelf and the gentle gradient of the valley's long profile. Incision was caused by high fluvial discharge during sea level fall. Decline of discharge and sediment supply during and after glacial maximum resulted in cessation of incision and in the formation of cemented beach ridges at the shelf-break.

The lowstand wedge of the last glacial cycle is well developed beyond the shelf-break and where the pre-existing shelf was deep. Where sampled it is deposited below wave-base. Its preservation is apparently the result of protection from wave and shelf-current action during regression. The subsequent transgressive wedge entirely dominates shelf deposition, infilling incised valleys, and contains vertically stacked fluvial, estuarine, littoral and sub-littoral elements. It is thin or absent beyond the shelf as a result of active oceanic currents hindering sedimentation. Active oceanic currents also result in only weak development of the highstand wedge. Energy regime, as represented by moderate shelf currents and variable fluvial discharge, has been the fundamental control on sediment architecture. Sediment supply has been of only secondary importance.
The evolution of the southern Menderes Massif in SW Turkey as revealed by zircon dating
Authors: LOOS STEFFEN , REISCHMANN THOMAS
Published: December 2007

This geochronological study concentrates on the evolution of the southern part of the Menderes Massif, a metamorphic core complex in W Turkey, by dating single zircons with the Pb–Pb evaporation and the U–Pb methods. We have analysed zircons from granitic augen gneisses of the core as well as from quartzites of the metasedimentary envelope. Zircons from the granitic core gneisses are euhedral with typical igneous morphologies. The single zircon ages of these gneisses indicate a time span for magmatic activity from 520 to 570 Ma with a major event at about 550 Ma. Some gneisses contain older zircons of
c.
660 Ma which are interpreted as inherited grains. Zircons from the quartzites are detrital as indicated by their rounded shapes and pitted surfaces. Their ages vary from 526 to 2094 Ma. These data partially coincide with the ages of the gneisses, but also indicate an older source region for the sediments. Neither a Tertiary origin nor metamorphic overgrowth is documented in the Pb ages of the zircons. The results suggest that the southern part of the Menderes Massif developed during a major magmatic episode in latest Proterozoic times, thus suggesting a relation with other Pan-African regions in N Africa.
Granitic melt viscosity and silicic magma dynamics in contrasting tectonic settings
Authors: CLEMENS J. D. , PETFORD N.
Published: December 2007

Models for granitic melt viscosities reveal the influences of H
2
O, temperature and tectonics on melt segregation, ascent and emplacement. Low-
T
magmas are wetter than those formed at high-
T,
so log
10
melt viscosity (Pa s) is 3.2–6.3 for leucogranite to tonalite, only 10–1000 times more viscous than basalts. There should be no correlation between critical dyke width (to prevent freezing) and tectonic setting. Granitic magma ascent rates in dykes vary by <10%, and melt extraction rates should be similar in different settings. Emplacement styles are not predetermined by composition or temperature, but by local structures and tectonics.
Crustal sources in Lower Palaeozoic rocks from NW Iberia: insights from laser ablation U–Pb ages of detrital zircons
Authors: FERNÁNDEZ-SUÁREZ J. , GUTIÉRREZ-ALONSO G. , JENNER G. A. , TUBRETT M. N.
Published: December 2007

Detrital zircons from greywackes belonging to an Ordovician volcanosedimentary-igneous complex in NW Spain were dated using the laser ablation-inductively coupled plasma-mass spectrometry technique. U–Pb results indicate the existence of three Pre-cambrian crustal sources in NW Iberia. The age grouping dated at
c
. 590–620 Ma confirms the presence of a Cadomian-Avalonian basement in this zone. The second age group (
c.
1.1–1.2 Ga) is the first evidence for a Grenvillean age crustal component in NW Iberia. The age grouping dated at
c.
1.9–2.0 Ga corresponds to the age of the Icartian igneous basement exposed in other areas of the European Variscides.
New zircon ages and regional significance for the evolution of the Pan-African orogen in Madagascar
Authors: KRÖNER A. , WINDLEY B. F. , JAECKELT P. , BREWER T. S. , RAZAKAMANANA T.
Published: December 2007

New
207
Pb/
206
Pb single zircon evaporation ages for granulites, gneisses and granites in southern and central Madagascar record a widespread Pan-African metamorphic and magmatic event in the period
c.
650–556 Ma, but also earlier ages in the range 1890–1710 Ma, inherited from protolith material and reflecting heterogeneous crustal sources. South of the Ranotsara shear zone, metasedimentary gneisses and granulites contain an early population of detrital zircons with ages in the range 1890–1740 Ma; a detrital grain with an age of 899 ± 2 Ma suggests that some sedimentary protoliths were deposited later than
c.
900 Ma. Metamorphic zircons have a mean age of 564.2 ± 0.9 Ma.

North of the Ranotsara shear zone, our data provide information on the age of source material of metamorphic rocks: 788.6 ± 0.7 Ma for the time of emplacement of the granitic precursor of a granulite-facies charnockite and 650.9 ± 0.9 Ma for the protolith age of an amphibolite-facies migmatitic gneiss. A structurally conformable alkali granite sheet with a crystallization age of 568.7 ±1.6 Ma contains xenocrystic zircons, one of which has an age of 1229.6 ± 1.0 Ma, inherited from the source of the anatectically derived material. The post-tectonic, alkalic Carion granite has an emplacement age of 556.0 ± 1.7 Ma and provides a minimum age for granulite- and amphibolite-facies metamorphism. Our field data indicate that extensional shear zones are common in central Madagascar, locally controlling amphibolite-facies retrogression of granulite-facies rocks and the emplacement of crustal melt granites. These events record the widespread extensional collapse of the Pan-African orogen in Madagascar.
Current controversies in the Caledonides
Authors: TANNER P. W. G. , BLUCK B. J.
Published: December 2007

This set of papers arose from a Discussion Meeting held in the Department of Geology & Applied Geology, University of Glasgow, on 9–10 September 1997. The aim of the Meeting was to review the progress which had been made in resolving some of the more controversial aspects of the pre-Silurian Caledonide geology of the British Isles and Scandinavia. It was also held to mark the retirements of two well-known Caledonide geologists: Professors Bernard Leake and Donald Ramsay. There were 34 talks and poster contributions, and the meeting was attended by over 100 people. We would like to thank our colleague Tim Dempster for helping to convene and organize the meeting.

It was fitting that the Meeting should be held in the Gregory Building, which was named after the Glasgow Professor who not only pioneered work on rift tectonics and regional uplift in Africa, but also wrote a perceptive book on ‘Dalradian Geology’ (
Gregory 1931
). In this work, Gregory pointed out that his observations were made over a period of 25 years, being made on ‘recreational weekends’, and mainly in winter ‘when the ground is less obscured by vegetation and the Highland mountains most attractive’: an approach motivated by a spirit of enquiry, and very productive, but one which would be out of step with current research strategies.

We would like to dedicate this set of papers to Mark Piasecki who died on 13 June 1999. Mark was the first person to draw attention to major problems concerning the relationship
Age of the Grampian orogeny in Scotland and Ireland
Authors: SOPER N. J. , RYAN P. D. , DEWEY J. F.
Published: December 2007

The previous conflict between stratigraphical and geochronological evidence for the age of the Grampian orogeny in Scotland and Ireland has now been largely resolved. Dalradian deposition continued on the Laurentian margin through late Proterozoic into Ordovician time. The Grampian orogeny was a brief, arc-accretion event that took place around the Arenig-Llanvirn boundary, at about 470 Ma, an extension of the Taconic orogeny of the Appalachians. Exhumation of the orogen was rapid; Rb-Sr mica ages that have been taken to indicate pre-Ordovician orogeny and slow cooling are considered to be problematical.
Polymorphic type inference for the named nested relational calculus
Authors: Bussche Jan Van den , Vansummeren Stijn
Published: December 2007

The named nested relational calculus is the canonical query language for the complex object database model and is equipped with a natural static type system. Given an expression in the language, without type declarations for the input variables, there is the problem of whether there are any input type declarations under which the expression is well-typed. Moreover, if there are, then which are they, and what is the corresponding output type for each of these? This problem is solved by a logic-based approach, and the decision problem is shown to be NP-complete.
Service-oriented computing
Authors: Casati Fabio
Published: December 2007

Workflow management and service composition technologies have been around for over twenty years now (or more, depending on who you ask and how you define them). The objective of these technologies is to automate process execution across people and systems. These technologies generated an incredible hype both in the academia and in the industry, at least in the software development industry. Hundreds of process and service composition models have been defined, thousands of papers have been written on the topic, and dozens of commercial workflow/service composition systems have been developed. With all this large effort, one would imagine that such technology is in widespread use and that, if not, the key problems have been identified and that is what generates so much effort from the research community. I believe that this is not the case.
An EBNF grammar for Wiki Creole 1.0
Authors: Junghans Martin , Riehle Dirk , Gurram Rama , Kaiser Matthias , Lopes Mario , Yalcinalp Umit
Published: December 2007

Today's wiki engines are not interoperable. This is an unfortunate consequence of the lack of rigorously specified standards. This technical report presents a complete and validated EBNF-based grammar for Wiki Creole, a community standard for wiki markup. Wiki Creole is also the only standard currently available. Wiki Creole is being specified using prose, leading to inconsistencies and ambiguities. Our grammar uncovered those ambiguities which we fed back into the specification process. The Wiki Creole grammar presented in this report makes the creation of Wiki Creole parsers simple using parser generators, ANTLR in our case. Using a precise specification of wiki markup lets us decouple wiki editors from wiki storage from further wiki processing tools. Based on this decoupling layer we expect innovation on these different parts to proceed independently and at a faster pace than before.
What is an analogue for the semantic web and why is having one important?
Authors: schraefel m. c.
Published: December 2007

This paper postulates that for the Semantic Web to grow and gain input from fields that will surely benefit it, it needs to develop an analogue that will help people not only understand what it is, but what the potential opportunities are that are enabled by these new protocols. The model proposed in the paper takes the way that Web interaction has been framed as a baseline to inform a similar analogue for the Semantic Web. While the Web has been represented as a Page + Links, the paper presents the argument that the Semantic Web can be conceptualized as a Notebook + Memex. The argument considers how this model also presents new challenges for fundamental human interaction with computing, and that hypertext models have much to contribute to this new understanding for distributed information systems.
Real users, real results
Authors: Brown Elizabeth , Fisher Tony , Brailsford Tim
Published: December 2007

This paper examines the current state of AEH (adaptive educational hypermedia) research into explicit learning style modelling for user personalisation. It addresses the problem of non-naïve test subjects, who are often in user trials, thus contributing to experimental bias. Instead, the authors suggest using "real people", i.e. users with a range of backgrounds and abilities, in order to gain a truer insight into evidence-based research.

We report on a study carried out with "real" users: around 80 children at a UK primary school. The study investigated sequential and global learning styles as a personalisation mechanism in an AEH system. The user trial involved matching and mismatching users and learning environments to see if learning improved. The AEH system used by the children was DEUS, a new e-learning platform that is conceptually similar to WHURLE, an AEH that also used learning styles as its user model.

No statistically significant differences were found between experimental groups, learning style preferences or learning environments. We discuss the significance of this, and then critically analyse the use of learning styles in relation to this study and also in the wider context.
MEmory performance
Authors: Bartolini S. , Foglia P. , Prete C. A.
Published: December 2007

In this issue, we present the papers from MEDEA-2006 Workshop [3] held in conjunction with the IEEE-ACM International Conference on Parallel Architectures and Compilation Techniques (PACT-2006) [1,2].
Data prefetching in a cache hierarchy with high bandwidth and capacity
Authors: Ramos Luis M. , Briz José Luis , Ibáñez Pablo E. , Viñals Victor
Published: December 2007

In this paper we evaluate four hardware data prefetchers in the context of a high-performance three-level on chip cache hierarchy with high bandwidth and capacity. We consider two classic prefetchers (Sequential Tagged and Stride) and two correlating prefetchers: PC/DC, a recent method with a superior score and low-sized tables, and P-DFCM, a new method. Like PC/DC, P-DFCM focuses on local delta sequences, but it is based on the DFCM value predictor. We explore different prefetch degrees and distances. Running SPEC2000, Olden and IAbench applications, results show that this kind of cache hierarchy turns prefetching aggressiveness into success for the four prefetchers. Sequential Tagged is the best, and deserves further attention to cut it losses in some applications. PC/DC results are matched or even improved by P-DFCM, using far fewer accesses to tables while keeping sizes low.
An LRU-based replacement algorithm augmented with frequency of access in shared chip-multiprocessor caches
Authors: Dybdahl Haakon , Stenström Per , Natvig Lasse
Published: December 2007

This paper proposes a new replacement algorithm to protect cache lines with potential future reuse from being evicted. In contrast to the recency based approaches used in the past (LRU for example), our algorithm also uses the notion of
frequency of access
. Instead of evicting the least recently used block, our algorithm identifies among a set of LRU blocks the one that is also least-frequently-used (according to a heuristic) and chooses that as a victim. We have implemented this replacement algorithm in a detailed simulation model of a chip multiprocessor system driven by SPEC2000 benchmarks. We have found that the new scheme improves performance for memory intensive applications. Moreover, as compared to other attempts, our replacement algorithm provides robust improvements across all benchmarks. We have also extended an earlier scheme proposed by Wong and Baer so it is switched off when performance is not improved. Our results show that this makes the scheme much more suitable for CMP configurations.
Internet nuggets
Authors: Thorson Mark
Published: December 2007

This column consists of selected traffic from the
comp. arch
newsgroup, a forum for discussion of computer architecture on the Internet---an international computer network.
Private use as fair use
Authors: Grodzinsky F. S. , Bottis M. C.
Published: December 2007

The age of digital technology has introduced new complications into the issues of fair and private use of copyrighted material. In fact, the question of private use of another's work has been transformed from a side issue in intellectual property jurisprudence into the very center of intellectual property discussions about rights and privileges in a networked world. This paper will explore the nuanced difference between fair and private use as articulated in the US and the European Copyright Laws. Part One will explain the legal use and meaning of fair use and its justifications. We maintain that it is almost impossible to resolve the issue of the fair/private use's legal nature, if one has not previously resolved
copyright's
legal nature. Legal resolution of such conflicts, as we shall demonstrate, follows different rules, and the messages sent to users and authors vary greatly depending on the jurisdiction. Part Two will examine the issue of Private Use as Fair Use by Design. We will look at the impact of Digital Rights Management on fair use and explore if the nature of private use as fair use has changed because we are dealing with the protection of digital content. We will show that protecting digital works by code, via various digital rights management schemes is shrinking the public domain of information and restricting private use as fair use.
Prudent policy?
Authors: Henderson K. A. , Spinello R. A. , Lipinski T. A.
Published: December 2007

The United States recognized intellectual property rights from its earliest days and included, in its constitution, a clause which expresses this, "To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries." These few words found in Article 1, Section 8, Clause 8 have grown into a massive body of laws that govern works that were unimaginable to Thomas Jefferson and his contemporaries. Our question today is very simple: is the latest metamorphosis of copyright law, the Digital Millennial Copyright Act of 1998 (DMCA), prudent policy? Specifically, we are concerned with three issues which critics have raised regarding this act: chilling effects on fair use, suppression of innovation, and overreach. We will also touch on the criticism which stresses that the DMCA further expands a system which increasingly and unfairly favors the content industries. This will be limited to illustrating extant tensions between copyright owners and society and also the difficulties law faces in keeping pace with the current, rapid and overwhelming technological and cultural change. We rely primarily on leading cases to establish the impact on fair use and innovation or to demonstrate over reach.
Free software and the political philosophy of the cyborg world
Authors: Chopra S. , Dexter S.
Published: December 2007

Our freedoms in cyberspace are those granted by code and the protocols it implements. When man and machine interact, co-exist, and intermingle, cyberspace comes to interpenetrate the real world fully. In this cyborg world, software retains its regulatory role, becoming a language of interaction with our extended cyborg selves. The mediation of our extended selves by closed software threatens individual autonomy. We define a notion of freedom for software that does justice to our conception of it as language, sketching the outlines of a social and political philosophy for a cyborg world. In a cyberspace underwritten by free software, political structures become contingent and flexible: the polity can choose to change the extent and character of its participation. The rejection of opaque power is an old anarchist ideal: free software, by making power transparent, carries the potential to place substantive restrictions on the regulatory power of cyborg government.
Digital futures
Authors: Horner D. S.
Published: December 2007

In this paper I argue that forecasting presents us with a paradox. Our ability to make reasonable and accurate medium to long term social and technological forecasts is demonstrably dismal. The gap between what actually happens and what was predicted is usually huge. Promoters and technological forecasters continue to provide us with wide varieties of technological futures. The paper introduces a tentative typology of technology futures as a framework for empirical work on failed technology futures. Sociological, psychological and historical explanations are considered for the forecasting paradox. But primarily I argue this is an ethical question. Forecasting is akin to promising and it is in this light it ought to be assessed. Forecasters are accountable for their forecasts in the same way I may be held accountable for my promises.
Electrochemical Behavior of High Nitrogen Ni-Free Austenitic Stainless Steels in L929 Cells and Cell Culture Medium
Authors: Alvarez Kelly P. , Hyun S.K. , Nakajima H. , Fujimoto S.
Published: December 2007

The localized corrosion behavior of high nitrogen Ni-free and Ni-reduced austenitic stainless steels in L929 mouse fibroblasts and cell culture medium (Eagle's minimum essential medium (MEM) supplemented with 10% fetal bovine serum (FBS)) was evaluated by electrochemical techniques in an electrochemical cell culture corrosion cell. The positive effect of nitrogen alloying was evidenced. The examined high nitrogen Ni-free and Ni-reduced alloys resulted to be immune to pitting corrosion even in the presence of cells. Cell culture studies showed that high nitrogen lotus-type porous Ni-free and Ni-reduced stainless steels were non-cytotoxic to mouse fibroblasts cell line. In this sense, they represent a better alternative to other conventional stainless steels.
Treatments for Enhancing Calcium and Phosphorus on Titanium Oxide Formed by Micro-arc Oxidation
Authors: Chen Mao-Teh , Liu Jian-Hong , Lin Chao-Sung
Published: December 2007

Anodic oxidation of titanium in the solution containing calcium (Ca) and phosphorus (P) compounds can prepare a Ca- and P-containing oxide film. However, during the galvanostatic anodizing process, both the porous inner layer formed prior to sparks and the crater-containing overlay formed with sparks resulted in decreasing the adhesion of the anodic film. Higher anodizing voltage can enhance the contents of Ca and P in the anodic film, yet leads to the adhesion decrease problem. Simulated body fluid (SBF) immersion after anodic oxidation in this study was reported to be able to increase the contents of Ca and P in the anodic film, and alkali- and heat-treatment (AHT) before SBF immersion further accelerated the reactions in SBF. Both the chemical and physical properties of the layer on the titanium specimen were optimized via these treatments above.
Charge Transport Analysis in DNA from the Aspect of Phonon Scattering
Authors: Yamanaka Takayuki , Vasudev Milana , Dutta Mitra , Stroscio Michael A.
Published: December 2007

Charge transport characteristics in a double-stranded DNA is discussed. Phonon scattering rates in DNA were calculated by a 1D quantum wire model. In addition, using the calculated phonon scattering rates, the carrier dynamics in DNA was simulated by Monte Carlo method. The simulation result shows rapid spread of charges from the initial point
Profile Measurements of Microscratches Remaining on Polished Si(001) Wafers
Authors: Shigetoshi Takushi , Inoue Haruyuki , Kawashima Tsukasa , Hirokane Takaaki , Kataoka Toshihiko , Morita Mizuho , Arima Kenta
Published: December 2007

We investigate the cross-sectional profile of microscratches remaining on a Si(001) wafer surface by a combination of laser light scattering and atomic force microscopy (AFM). AFM observations reveal that most microscratches detected by laser light scattering are very shallow trenches with widths and depths of 80-200 nm and 0.10-0.20 nm, respectively. A ridge- shaped structure with a height of 0.10 nm is also found. These results demonstrate that the combined method of laser light scattering with AFM enables us to not only detect atomic- scale defects on a Si wafer, but to also speculate when microscratches are formed during chemical mechanical polishing (CMP) processes.
Tuning the Removal Rate of Carbon Doped Oxide during Chemical Mechanical Polishing
Authors: Liu Zhendong , Bian Jinru
Published: December 2007

Most integration schemes require CMP barrier slurries to have high SiO2 and tunable carbon doped oxide (CDO) removal rates (RR). An additive, T, is able to enhance the SiO2 rate at low pH, but greatly suppressed the CDO RR at the concentration providing maximum SiO2 RR. With the addition of another additive, Z or P, the CDO rate could be tuned upward while not affecting the SiO2 RR substantially. Additives Z and P are anionic surfactants with short to intermediate chain length. They are effective only in the presence of T, which suggests a synergistic effect between the additives. Contact angle studies and SIMS analysis indicate that in the presence of T, Z was adsorbed only on SiO2, but not on CDO. Without T in the slurry, Z could not be adsorbed on either film. It was proposed that the adsorption of Z onto silica abrasive made the colloidal silica particle more hydrophobic, leading to greatly enhanced impact on the hydrophobic CDO sur face.
Differential regulation of ERK1/2 and p38 MAP kinases in VacA-induced apoptosis of gastric epithelial cells
Authors: Ki Mi-Ran , Lee Hye-Rim , Goo Moon-Jung , Hong Il-Hwa , Do Sun-Hee , Jeong Da-Hee , Yang Hai-Jie , Yuan Dong-Wei , Park Jin-Kyu , Jeong Kyu-Shik
Published: December 2007

Helicobacter pylori vacuolating cytotoxin A (VacA) has been considered as an apoptosis-inducing factor. Here, we investigated the mechanism of VacA-induced apoptosis in relation to the defense mechanism and MAP kinases pathway in gastric epithelial cells. AGS cells exposed to enriched VacA extracts affected the level of SOD-1 and villin. We further investigated the role of VacA in those inductions using a functional recombinant VacA (rVacA). Activation of p38 MAPK and Bax dimerization by rVacA were increased in a dose-dependent manner. rVacA-induced ERK1/2 MAPK activation was maximal at 30 min and 4 h and 1–4 μg/ml of rVacA. rVacA-induced SOD-1 expression was considerably diminished by inhibiting ERK1/2 MAPK and it was slightly increased by inhibiting p38 MAPK. rVacA increased or decreased villin expression depending on dose and exposure time and its expression was mainly appeared in the contractile actin ring of the dividing cells. Despite its cytoprotective effect, SB-203580, a p38 inhibitor, was unlikely to reduce VacA-induced Bax dimerization and rather inhibited villin and Bcl2 expression, indicating that p38 may also play a role in cell proliferation or differentiation for survival after VacA intoxication. Furthermore, p38 inhibitor accelerated rVacA-induced cell death after exposure of AGS cells to H2O2but ERK1/2 inhibitor protected cells from H2O2insult. These results suggest that SOD-1 and villin are expressed differentially upon VacA insult depending on dose and exposure time via ERK and p38 MAP kinases; decrease in SOD-1 and villin expression coupled with Bax dimerization leads to apoptosis of gastric epithelial cells.
Anandamide inhibits cholangiocyte hyperplastic proliferation via activation of thioredoxin 1/redox factor 1 and AP-1 activation
Authors: DeMorrow Sharon , Francis Heather , Gaudio Eugenio , Ueno Yoshiyuki , Venter Julie , Onori Paolo , Franchitto Antonio , Vaculin Bradley , Vaculin Shelley , Alpini Gianfranco
Published: December 2007

The endocannabinoid system regulates various aspects of hepatic fibrosis; however, nothing is known about its role in regulating cholangiocyte proliferation and function. We evaluated the effects of anandamide (AEA) on cholangiocyte proliferation and explored the effects of AEA on the thioredoxin 1 (TRX1)/redox factor 1 (Ref1)/activator protein-1 (AP-1) pathway. Mice underwent bile duct ligation (BDL) and were infused with AEA for 3 days postsurgery. Proliferation and apoptosis were evaluated in liver sections. Effects of in vitro AEA treatment on cholangiocyte proliferation and apoptosis were studied in purified cholangiocytes. The relative expression of cannabinoid receptors was also assessed in liver sections and cholangiocytes. mRNA expression of the cannabinoid receptors Cb1 and VR1 was decreased after BDL, whereas there was an upregulation of Cb2 mRNA. AEA decreased cholangiocyte growth and induced accumulation of reactive oxygen species, upregulation of TRX1, Ref1, c-Fos, and c-Jun expression, increased nuclear localization of TRX1, and increased AP-1 transcriptional activity. Specific knockdown of TRX1 or Ref1 expression ablated the AP-1 transcriptional activity and AEA-induced cell death but not expression of c-Fos and c-Jun. Knockdown of c-Fos and c-Jun expression also ablated AEA-induced apoptosis. We conclude that AEA suppresses cholangiocyte proliferation during cholestasis via a Cb2-dependent mechanism. Modulation of the endocannabinoid system may be important in the treatment of cholangiopathies.
New primary culture systems to study the differentiation and proliferation of mouse fetal hepatoblasts
Authors: Miki Rika , Tatsumi Norifumi , Matsumoto Ken , Yokouchi Yuji
Published: December 2007

Hepatoblasts have the potential to differentiate into both hepatocytes and biliary epithelial cells through a differentiation program that has not been fully elucidated. With the aim to better define the mechanism of differentiation of hepatoblasts, we isolated hepatoblasts and established new culture systems. We isolated hepatoblasts from E12.5 fetal mouse liver by using E-cadherin. The E-cadherin+ cells expressed α-fetoprotein (AFP) and albumin (Alb) but not cytokeratin 19 (CK19). Transplantation of the E-cadherin+ cells into mice that had been subjected to liver injury or biliary epithelial injury led to differentiation of the cells into hepatocytes or biliary epithelial cells, respectively. In a low-cell-density culture system in the absence of additional growth factors, E-cadherin+ cells formed colonies of various sizes, largely comprising Alb-positive cells. Supplementation of the culture medium with hepatocyte growth factor and epidermal growth factor promoted proliferation of the cells. Thus the low-cell-density culture system should be useful to identify inductive factors that regulate the proliferation and differentiation of hepatoblasts. In a high-cell-density system in the presence of oncostatin M+dexamethasone, E14.5, but not E12.5, E-cadherin+ cells differentiated into mature hepatocytes, suggesting that unidentified factors are involved in hepatic maturation. Culture of E-cadherin+ cells derived from E12.5 or E14.5 liver under high-cell-density conditions should allow elucidation of the mechanism of hepatic differentiation in greater detail. These new culture systems should be of use to identify growth factors that induce hepatoblasts to proliferate or differentiate into hepatocytes and biliary epithelial cells.
Gastrocnemius muscle specific force in boys and men
Authors: Morse Christopher I. , Tolfrey Keith , Thom Jeanette M. , Vassilopoulos Vasilios , Maganaris Constantinos N. , Narici Marco V.
Published: December 2007

The aim of this study was to assess whether the in vivo specific force and architectural characteristics of the lateral gastrocnemius (GL) muscle of early pubescent boys ( n = 11, age = 10.9 ± 0.3 yr, Tanner stage 2) differed from those of adult men ( n = 12, age = 25.3 ± 4.4 yr). Plantarflexor torque was 55% lower in the boys (77.4 ± 21.4 N·m) compared with the adults (175.6 ± 31.7 N·m, P < 0.01). Physiological cross-sectional area (PCSA), determined in vivo using ultrasonography and MRI, was 52% smaller in the boys ( P < 0.01). No difference was found in pennation angle, or in the ratio of fascicle length ( Lf) to muscle length between the boys and men. Moment arm length was 25% smaller in the boys ( P < 0.01). Antagonist coactivation, assessed using surface EMG on the dorsiflexors, was not different between the boys and men (11.8 ± 6.7% and 13.5 ± 5.8%, respectively). Surprisingly, GL force normalized to PCSA (specific force) was significantly higher (21%) in the boys than in the men (13.1 ± 2.0 vs. 15.9 ± 2.7 N/cm2, P < 0.05). This finding could not be explained by differences in moment arm length, muscle activation, or architecture, and other factors, such as tendinous characteristics and/or changes in moment arm length with contraction, may be held responsible. These observations warrant further investigation.