bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Chronic Ethanol Administration on Production of and Response to Erythropoietin in the Mouse
Authors: Giglio Maximo J. , Santoro Rosario C. , Bozzini Carlos E.
Published: September 2007

Male adult mice were allowed to drink only a solution of 32% ethyl alcohol for 3 months. Hematocrit and hemoglobin concentration were lower in ethanol‐treated than in control mice at the end of the experimental period. Red cell volume was not significantly different between both groups. Plasma volume was higher in experimental than in control mice. Therefore, the anemia found in ethanol‐treated mice can be regarded as a dilution anemia. When ethanol‐treated and control mice, both made polycythemic by hypertransfusion to suppress their endogenous erythropoietin formation, were injected with doses of erythropoietin in the range of 0.2 to 3.2 IRP units, the derived dose‐response curves were markedly different because of a reduced response to the hormone by the treated mice. This finding suggests that the number of “erythropoietin‐responsive cells” may be reduced as the result of ethanol, or that their response to the hormone may be delayed or inhibited. Plasma erythropoietin concentration in alcohol‐treated mice, as determined in the posthypoxic polycythemic mouse bioassay, was higher than normal in both normoxic and hypoxic conditions, probably as the result of the impaired responsiveness to the hormone mentioned above.
Cutaneous Vascular Sensitivity to Lower Aliphatic Alcohols and Aldehydes in Orientals
Authors: Wilkin Jonathan K. , Fortner Glenn
Published: September 2007

An ethnic predisposition to ethanol‐provoked flushing among diverse Mongoloid populations may be the consequence of a delayed oxidation and accumulation of acetakfehyde. Orientals who flush after oral alcohol are more likely to have cutaneous erythema after topical ethanol or propanol, and the cutaneous vascular reaction to primary alcohols is actually provoked by the corresponding aldehyde. The cutaneous reaction to primary alcohols can be totally blocked by pretreatment with 4‐methylpyrazole, a potent inhibitor of alcohol dehydrogenase.
Gangliosides in Axolemmal and Synaptic Membrane Fractions from Developing Rats: Effects of Maternal Ethanol Consumption on Offspring
Authors: Noronha Antonio B. , Druse Mary J. , Gnaedinger Jean M. , Kelly Gerard M.
Published: September 2007

Previous work from this laboratory has shown that in utero exposure to ethanol significantly alters the synthesis of glycoproteins in synaptic, axolemmal, and myelin membranes from developing rats. In an attempt to determine whether in utero exposure to ethanol similarly alters the synthesis of other glycoconjugates involved with cell‐cell interactions, the present study examined the influence of chronic maternal ethanol consumption prior to parturition on the content and synthesis of gangliosides in axolemmal and synaptic plasma membranes from developing rats. The results demonstrate that, in contrast to central nervous system glycoproteins, synaptic and axolemmal glycoUpids are minimally affected by in utero exposure to ethanol. At all ages examined (17 to 34 days of age), the offspring of control and ethanol‐treated rats had a comparable distribution of radiolabel among synaptic and axolemmal gangliosides, a normal concentration of ganglioside sialic acid in synaptic plasma membranes, and a near‐normal distribution of sialic acid among synaptic gangliosides. The present study provides evidence which indicates that the radiolabeling patterns of axolemmal and synaptic membrane gangliosides are similar. Specifically, the most heavily labeled synaptic and axolemmal gangliosides were G11b (20–37% of the total radioactivity) and G01s (20–32%). A smaller proportion of radioactivity was associated with G01b (∼ 11–16%), GM1 (5–10%), and G01b (4–11%), as well as with GD3 and the other monosialogangliosides (< 5%). During the age period examined the proportion of radioactive Grit increased in both membrane fractions.
The temporal responses of protein synthesis, gene expression and cell signalling in human quadriceps muscle and patellar tendon to disuse
Authors: De Boer Maarten D. , Selby Anna , Atherton Philip , Smith Ken , Seynnes Olivier R. , Maganaris Constantinos N. , Maffulli Nicola , Movin Tomas , Narici Marco V. , Rennie Michael J.
Published: September 2007

We hypothesized that rates of myofibrillar and patellar tendon collagen synthesis would fall over time during disuse, the changes being accompanied in muscle by decreases in focal adhesion kinase (FAK) phosphorylation and in gene expression for proteolytic enzymes. We studied nine men (22 ± 4 years, BMI 24 ± 3 kg m−2 (means ±s.d.) who underwent unilateral lower leg suspension for 23 days; five were studied between 0 and 10 days and four between 10 and 21 days. Muscle and tendon biopsies were taken in the postabsorptive state at days 0, 10 and 21 for measurement of protein synthesis, gene expression and protein phosphorylation. Muscle cross‐sectional area decreased by 5.2% at 14 days and 10.0% (both P < 0.001), at 23 days, i.e. 0.5% day−1, whereas tendon dimensions were constant. Rates of myofibrillar protein synthesis fell (P < 0.01) from 0.047% h−1 at day 0 to 0.022% h−1 at 10 days without further changes. Tendon collagen synthetic rates also fell (P < 0.01), from 0.052 to 0.023% h−1 at 10 days and then to 0.010% h−1 at 21 days. FAK phosphorylation decreased 30% (P < 0.01) at 10 days. No changes occurred in the amounts/phosphorylation of PKB–P70s6k–mTOR pathway components. Expression of mRNA for MuRF‐1 increased ∼3‐fold at 10 days without changes in MAFbx or tripeptidyl peptidase II mRNA, but all decreased between 10 and 21 days. Thus, both myofibrillar and tendon protein synthetic rates show progressive decreases during 21 days of disuse; in muscle, this is accompanied by decreased phosphorylation of FAK, with no marked increases in genes for proteolytic enzymes.
Paired-End Mapping Reveals Extensive Structural Variation in the Human Genome
Authors: Korbel Jan O. , Urban Alexander Eckehart , Affourtit Jason P. , Godwin Brian , Grubert Fabian , Simons Jan Fredrik , Kim Philip M. , Palejev Dean , Carriero Nicholas J. , Du Lei , Taillon Bruce E. , Chen Zhoutao , Tanzer Andrea , Saunders A. C. Eugenia , Chi Jianxiang , Yang Fengtang , Carter Nigel P. , Hurles Matthew E. , Weissman Sherman M. , Harkins Timothy T. , Gerstein Mark B. , Egholm Michael , Snyder Michael
Published: September 2007

Structural variation of the genome involves kilobase- to megabase-sized deletions, duplications, insertions, inversions, and complex combinations of rearrangements. We introduce high-throughput and massive paired-end mapping (PEM), a large-scale genome-sequencing method to identify structural variants (SVs) ∼3 kilobases (kb) or larger that combines the rescue and capture of paired ends of 3-kb fragments, massive 454 sequencing, and a computational approach to map DNA reads onto a reference genome. PEM was used to map SVs in an African and in a putatively European individual and identified shared and divergent SVs relative to the reference genome. Overall, we fine-mapped more than 1000 SVs and documented that the number of SVs among humans is much larger than initially hypothesized; many of the SVs potentially affect gene function. The breakpoint junction sequences of more than 200 SVs were determined with a novel pooling strategy and computational analysis. Our analysis provided insights into the mechanisms of SV formation in humans.
LIMITED RESOLUTION AND MULTIRESOLUTION METHODS IN COMPLEX NETWORK COMMUNITY DETECTION
Authors: KUMPULA JUSSI M. , SARAMÄKI JARI , KASKI KIMMO , KERTÉSZ JÁNOS
Published: September 2007

Detecting community structure in real-world networks is a challenging problem. Recently, it has been shown that the resolution of methods based on optimizing a modularity measure or a corresponding energy is limited; communities with sizes below some threshold remain unresolved. One possibility to go around this problem is to vary the threshold by using a tuning parameter, and investigate the community structure at variable resolutions. Here, we analyze the resolution limit and multiresolution behavior for two different methods: a q-state Potts method proposed by Reichard and Bornholdt, and a recent multiresolution method by Arenas, Fernández, and Gómez. These methods are studied analytically, and applied to three test networks using simulated annealing.
COMMUNITY DYNAMICS IN SOCIAL NETWORKS
Authors: PALLA GERGELY , BARABÁSI ALBERT-LÁSZLÓ , VICSEK TAMÁS
Published: September 2007

We study the statistical properties of community dynamics in large social networks, where the evolving communities are obtained from subsequent snapshots of the modular structure. Such cohesive groups of people can grow by recruiting new members, or contract by loosing members; two (or more) groups may merge into a single community, while a large enough social group can split into several smaller ones; new communities are born and old ones may disappear. We find significant difference between the behavior of smaller collaborative or friendship circles and larger communities, eg. institutions. Social groups containing only a few members persist longer on average when the fluctuations of the members is small. In contrast, we find that the condition for stability for large communities is continuous changes in their membership, allowing for the possibility that after some time practically all members are exchanged.
NOISE CHARACTERISTICS AND RELIABILITY OF LIGHT EMITTING DIODES BASED ON NITRIDES
Authors: PRALGAUSKAITĖ SANDRA , PALENSKIS VILIUS , MATUKAS JONAS , PETRULIS JUOZAS , KURILČIK GENADIJUS
Published: September 2007

Optical and electrical noises and correlation factor between optical and electrical fluctuations of nitride-based light emitting diodes (LEDs) have been investigated under forward bias. Their electrical, optical and noise characteristics were compared with ones of LEDs of other materials. LED noise characteristic changes during aging have been measured, too. It is found that optical and electrical noise spectra under forward bias for more reliable LEDs distinguish by lower l/f type fluctuations and Lorentzian type noise at higher frequencies. LEDs with intensive 1/f noise demonstrate shorter lifetime. It is shown that reason of LED degradation is related with defects presence in device structure. These defects can be formed during device fabrication or appear during operation. An analysis of LED current-voltage and electrical noise characteristics under forward and reverse bias has shown that LEDs with intensive 1/f electrical noise, large reverse current (low reverse breakdown voltage) and larger terminal voltage under forward bias distinguish by short lifetime.
NOISE CHARACTERISTIC AND QUALITY INVESTIGATION OF ULTRAFAST AVALANCHE PHOTODIODES
Authors: PRALGAUSKAITĖ SANDRA , PALENSKIS VILIUS , MATUKAS JONAS , VIZBARAS AUGUSTINAS
Published: September 2007

A detailed study of photosensitivity and noise characteristics of ultrafast InGaAsP / InP avalanche photodiodes (APDs) with separate absorption, grading, charge and multiplication regions was carried out. Carrier multiplication and noise factors were evaluated. Noise origin in investigated APDs is 1/f, generation-recombination and shot noises. Different quality samples have been investigated and it is shown that noise characteristics well reflect APD quality problems. It is shown that low-frequency noise and excess shot noise characteristics are very sensitive to the APD quality problems and clear up physical processes in device structure. Noise characteristic analyses can be used for the APD quality problems revealing and optimal design development.
Using Latent Semantic Indexing to Improve the Accuracy of Document Clustering
Authors: Zhan Jiaming , Loh Han Tong
Published: September 2007

Document clustering is a significant research issue in information retrieval and text mining. Traditionally, most clustering methods were based on the vector space model which has a few limitations such as high dimensionality and weakness in handling synonymous and polysemous problems. Latent semantic indexing (LSI) is able to deal with such problems to some extent. Previous studies have shown that using LSI could reduce the time in clustering a large document set while having little effect on clustering accuracy. However, when conducting clustering upon a small document set, the accuracy is more concerned than efficiency. In this paper, we demonstrate that LSI can improve the clustering accuracy of a small document set and we also recommend the dimensions needed to achieve the best clustering performance.
Applying Sense-Making and Narrative Techniques to Capture Lessons Learnt
Authors: Cheuk Bonnie
Published: September 2007

This case study demonstrates how we have designed a knowledge management project around story-telling ("narrative" feedback). The aim is to create a global virtual space for sharing of good and bad experiences from the commissioning pilot. This project is also designed to help senior managers understand the experiences of the pilot phase of a major change programme within the British Council. The change programme (referred to as commissioning change programme) is about introducing a new internal model/process to release funding to support new products and services' development and implementation.

The research design is informed by Dervin's sense-making theory and Snowden's Cynefin framework and mass narrative representation tools. Telephone and face-to-face interviews were conducted with 30 colleagues in the UK and overseas. An initial indirect question was posed to respondents—"What was your experience with the commissioning pilot?"—to capture their stories. The stories told were transcribed and indexed and patterns were identified. The analysis helps to highlight the problematic areas as well as opportunities for improvement.

This case study demonstrates the potential of using narratives to evaluate and capture learning points which can be viewed by managers and staff using multiple perspectives. This approach complements the traditional approach of producing an evaluation report which would be written for a specific group of audience, such as the senior management team.
A new field technique for sealing and packing rock and soil samples
Authors: Stimpson Brian , Metcalfe Richard George , Walton Geoffrey
Published: September 2007

A field technique is described for sealing and packing cores of rock and soil in a rigid plastic foam. Initial tests indicate that absolute moisture content losses of 1 per cent or less are obtainable for periods of up to six months.
Some engineering aspects of rock weathering with field examples from Dartmoor and elsewhere
Authors: Fookes Peter George , Dearman William Robert , Franklin John Allan
Published: September 2007

Weathering and weatherability have been defined and a general scheme of weathering classification has been developed for engineering.

Fundamental mechanical changes in behaviour due to weathering are considered for both intact rock and discontinuous rock, and a brief study is made of available field and laboratory tests to assess weathering and weatherability. From this, suggestions are made for classification schemes designating rock quality for mapping and core logging.

The results of fieldwork and laboratory studies on weathered rocks mainly from the Dart-moor area, S.W. England, are given. Several different rock types, including granite, dolerite, limestone and mudstone, have been classified on the weathering scale, tested in the field by point loading and Schmidt hammer, and laboratory determinations of strength and porosity made. The results show clear trends of decreasing strength and fracture spacing with increased weathering and general conclusions and observations on engineering weathering classifications have been drawn. In early stages of weathering it appears that there is a general increase of fractures per unit volume and in later stages of weathering there is a rapid increase in chemical decay. In addition, geometrical distributions of weathering in fold and fault situations have been examined.

The full implications of Tertiary warm climate weathering and Quaternary cold climate weathering are not yet clear.
P. M. JAMES: The behaviour of a soft recent sediment under embankment loadings
Authors: Tan S. B.
Published: September 2007

From S. B. T
an
:

The author has interpreted his results on secondary consolidation by using the empirical approach of Buisman. The writer (Tan, 1971) has suggested that an improved empirical approach would be to plot the ratio of the time to settlement against time in which a straight line would ensue, as shown by the following equation:—

t
/δ =
Mt
+
C

in which δ is the total settlement at time t after the dissipation of excess pore water pressure,
M
and
C
are empirical constants. The inverse slope 1/
M
of Equation (1) will yield the ultimate settlement thus overcoming the shortcomings of Buisman's approach in which the settlement does not seem to terminate.

Using the author's results (Fig. 6), the plot of
t
/δ against
t
is presented in Fig. 1. It is readily seen that Equation (1) is practically followed except for the first few points when the time is small (i.e. when primary settlement predominates). The ultimate settlement evaluated from the inverse slope 1/
M
is as follows:—

North Embankment 5.75 feet

South Embankment 3.55 feet

It would appear from the above that the author's estimate of over 6 feet (North Embankment) and over 3 feet (South Embankment) would be the final settlement and this would take place over a period of about ten years.

In Fig. 2, the predicted field settlement/time curve (using Equation (1) and the empirical constants
M
and
C
derived from Fig. 1) is shown. It is observed that there is good agreement between the actual and the calculated
The functions of the Engineering Geologist in urban development
Authors: Taylor Roy Kenneth
Published: September 2007

The participation of the engineering geologist in urban development can be considered under four principal functions—geological interpretation, data acquisition (pre-site investigation), collation of geotechnical data, recording (and publication) of case histories. Examples cited from the North of England demonstrate that these functions are interrelated and that there is much in favour of local authorities themselves employing engineering geologists.
Large scale geomorphological mapping and Highway engineering design
Authors: Brunsden Denys , Doornkamp John Charles , Fookes Peter George , Jones David Keith Crozier , Kelly John Michael Hunter
Published: September 2007

Geomorphological mapping in site investigations for highway engineering is proving to be a rapid means of obtaining much relevant information about ground conditions. Such mapping requires the recognition of both the origin of surface features and the geological processes that still influence them. In addition information about materials is recorded and inferences made about their extent.

The paper identifies eight aims of a geomorphological survey for highway engineering and discusses these in the context of small-scale maps and large-scale plans. The latter are illustrated by case studies from Nepal and South Wales.

The review identifies the established applications of geomorphological mapping to site investigation and concludes that further work can usefully be directed towards a broadening of the geomorphological content of site investigation.
Old mine shafts and their location by geophysical surveying
Authors: Maxwell George M.
Published: September 2007

Local Authorities cannot permit surface development without giving due weight to what is known, or can be conjectured about the stability of the site with regard to underground workings. Part of these underground workings are the shafts and adits leading into them. Developers should be anxious to locate the surface entrances to such shafts and adits, because the possibility that they might collapse leaves the present and future stability of the site uncertain.

The records of old mine shafts
. In 1873, it became the statutory duty of the owners of mines to send plans of the boundaries of abandoned workings to the Secretary of State (Maxwell 1964). These plans should include the position of the shafts. Unfortunately, there are few plans in existence of the workings of almost 4 000 million tonnes of coal, ironstone and other economic deposits abandoned before 1873. The reason for the absence of such plans is that until 1873, there was no statutory duty for the owner of a mine, other than of coal or ironstone, to make a plan of the workings. Plans of the workings of coal-mines date from 1850, and or ironstone mines from 1860.

In all there should be three plans of the workings of a mine. The working plan and the abandonment plan made by the mine owner, and a working plan kept by the mineral owner. Following an appeal for the deposition of old working plans in 1925, many of them, pre-dating 1873, have been catalogued. A further appeal
Hydrochemistry and groundwater flow patterns in the vicinity of Stratford-upon-Avon
Authors: Lloyd John W.
Published: September 2007

Standard hydrochemistry is used in conjunction with fault control to define the directions of groundwater flow in the Keuper Sandstone aquifer in the vicinity of Stratford-upon-Avon. Four hydrochemical groundwater types are defined. The hydrochemistry confirms the presence of a cone of depression in the area, reinforcing the evidence of water level trends. Environmental isotopes are used to substantiate the standard chemistry and show that the water being abstracted is very old groundwater derived from storage.
Late Quaternary scour-hollows and related features in central London
Authors: Berry F. G.
Published: September 2007

Drift-filled hollows (rock-head depressions) which occur beneath Lower Floodplain deposits of Ipswichian to Recent age in central London can be related to shallow buried ‘channels’ (elongate closed hollows). Twenty-six depressions are represented on a map of the channels and other buried features and are individually described. Most of these are grouped in the South Lambeth–Battersea–Westminister–Southwark area and are formed in the surface of the London Clay. They often appear to coincide with stream junctions in the Recent drainage pattern. Under-drainage may occur in some depressions through contact with underlying granular Lower Tertiary sediments. In some cases, these deposits appear to have risen above the adjacent levels as diapiric features, possibly at the time when deepening of the hollows occurred.
A microcomputer based system to provide report quality borehole records
Authors: Howland A. F. , Podolski N.
Published: September 2007

A system has been developed to provide report quality borehole records with the aid of a microcomputer. Its aim is to provide a greater efficiency in the production of such records without jeopardizing the technical content or their reliability. The system, which consists of a suite of menu-driven programs, has been developed on a small machine which has only limited capabilities compared with many alternatives currently available. The careful development of the system has provided the facility of attaching further programs able to access the data and carry out functions which will produce further savings in the operational and business affairs of the user practice. The successful development of the system illustrates that user needs do not necessarily require equipment at the forefront of hardware development.
Thermal conductivities of marine sediments
Authors: Lovell M. A.
Published: September 2007

Proposals to lay fibre-optic communication systems on the sea floor have prompted renewed interest in the thermal properties of marine sediments. Of particular interest is the recognition of rapid variations in the thermal conductivity of near-surface sediments.

The thermal conductivity of non-cohesive sediments is investigated and shown to be adequately expressed by a simple geometric equation using volumetric and conductivity values for the components. Similar results pertain for previously reported measurements on cohesive sediments.

Electrical formation factor is known to be related to porosity for most marine sediments, and it is shown that the electrical and thermal parameters may in turn be related through this common parameter. This opens the way for the use of continuous electrical profiling as a practical and relatively inexpensive means of mapping lateral variations in the thermal conductivity of surface sediments.
An investigation of metal enrichment in Triassic Sandstones and porewaters below an effluent spreading site, West Midlands, England
Authors: Spears D. A.
Published: September 2007

Soil and sandstone samples were taken from below a sewage effluent spreading site at Whittington Hall, near Stourbridge. The sandstones belong to the Triassic Sherwood Sandstone Group, whole rock samples were analysed for major and trace elements, and porewaters (extracted by high speed centrifuge) for trace metals. The elements found to be enriched in the sediments, at shallow depths (generally not greater than 1 m) were, in order, Zn, Pb, Cu, Cr, Ni and Sr. Systematic decreases with depth were not recorded for the elements Mn, V, Rb, Y and Zr. Retention of the metals is believed to be a combination of filtration of particulate matter and reaction with the sediment, particularly the oxyhydroxide material and possibly smectites. The observed metal enrichment corresponds with the effluent composition and in the case of Zn there would appear to be an approximate balance between the total input into the system and the amount retained in near-surface sediment. The borehole samples were frozen on site in order to suppress microbial changes in the porewaters. Metal concentrations in the porewaters were not, in general, affected but significant differences were noted for Fe, Mn and Ca. At depth in the unsaturated and saturated zones porewater concentrations approach the ‘natural’ background concentration. These decreases in concentrations take place below the zone of sediment-porewater reaction based on whole-rock analyses and are therefore attributed to progressive dilution of the porewater and groundwater.
Book Review SuttonB. H. C.Solving Problems in Soil Mechanics1986LongmanHarlow, Essex£8.95, soft cover;2340 582 98810 1
Authors: Atkinson J. H.
Published: September 2007

There are now plenty of text books available on soil mechanics, foundations, retaining walls, slope stability and other related topics by UK authors and any new book should offer something fresh. This might be by treating the material with new clarity or by dealing with new material or by having a different teaching approach (e.g. by programmed instruction). This book is different from many others in the field, consisting almost entirely of worked answers to questions taken largely from CEI, ICE, University of London and Scottish Technical Education Council examination papers. There are very short sections of text (often only a few lines) introducing a particular topic followed by examination questions highlighted in boxes with model solutions. At the end of each chapter there are problems (also taken from old examination papers) with answers but without working.

The material covered in the book can be judged from the eight chapter headings: Physical properties and classification of soil, Permeability of soil and flow nets, Compressibility of soil and settlement of foundations, The shearing resistance of soil, Lateral soil pressures, The stability of slopes, Bearing capacity of soil and stability of foundations, Compaction and stabilization of soil. The material is similar to that which appears in the reviewer's undergraduate notes taken at Imperial College nearly 25 years ago and most of the examination questions used in the book could very well be of the same vintage. The material covered is decidedly old fashioned and nothing is said at all about the major
Volcanism and continental break-up: a global compilation of large igneous provinces
Authors: Coffin Millard F. , Eldholm Olav
Published: September 2007

Large igneous provinces (LIPs) include continental flood basalts and associated intrusive rocks, volcanic passive margins, oceanic plateaus, submarine ridges, seamount groups, and ocean basin flood basalts. In some cases transient episodes of voluminous magmatism are temporally and spatially related to continental break-up, e.g. North Atlantic Volcanic Province, Deccan Traps, Paraná-Etendeka basalts. In other cases, however, no relationships are apparent, e.g. Siberian flood basalts, Columbia River flood basalts. Herein we review LIPs worldwide in order to better understand their relationship to the break-up and separation of lithospheric plates. The two most voluminous episodes known of basaltic magmatism not associated with the creation of ‘normal’ oceanic crust, the emplacements of the Ontong Java and Kerguelen plateaus, do not appear to be linked to continental break-up. Volcanic passive margins have now been identified on the edges of many continents, and are clearly related to continental break-up and separation. They cannot always, however, be tied to continental flood basalts. Ocean basin flood basalts and seamount groups are not commonly related to continental break-up. In most instances submarine ridges show temporal and spatial relationships with continental flood basalt provinces or oceanic plateaus. Observational data suggest that existing models do not adequately explain all LIPs; we suggest that a thermally and chemically heterogeneous asthenosphere, occasionally penetrated by deep mantle plumes, can account for their origin.
The response of geomorphic systems to climatic and hydrological change during the Late Glacial and early Holocene in the humid and sub-humid tropics
Authors: Thomas Michael F. , Thorp Martin B.
Published: September 2007

Dated alluvial stratigraphies indicative of late Quaternary environmental change in the humid tropics have increased, but the database remains inadequate and the intensity and duration of wet-dry oscillations and responses of hillslopes and river systems remain poorly understood. Dry conditions at the Last Glacial Maximum were marked by semi-arid landforms with reduced stream activity. Large palaeofloods, valley-floor erosion, channel cutting and flood deposition occurred at the Pleistocene-Holocene transition after 13 000 BP. Distinctive floodplains and stratigraphies characterized by multiple shifts from lateral to vertical accretion were built initially over a period of nearly 2 ka after 9 500 BP during the early Holocene pluvial in Africa, Kalimantan and Amazonia during and after re-establishment of the lowland rainforests. Several wet-dry climatic oscillations followed in the mid-Holocene period and are marked by alluvial cut and fill sequences and by slightly thinner but coarse textured floodplain overbank sediments.
The Past Global Changes (PAGES) Project
Authors: Pilcher J. R.
Published: September 2007

PAGES is a core project of the International Geosphere Biosphere program. Its role is to provide a quantitative understanding of the Earth’s past environment and the envelope of natural variability within which we can assess anthropogenic climate changes. The Project is organized into two main time frames: STREAM 1 which covers the last 2000 years and STREAM 2 which covers the last two glacial/interglacial cycles. Within these time frames PAGES has organized a series of Activites and Tasks, the largest of which are three transects from the Arctic to the Antarctic, one through Europe and Africa, one through Siberia, China and Australia and one down the west side of the Americas. In each case PAGES is seeking to co-ordinate the activities of local researchers and bring together scientists from different research backgrounds: tree-rings, corals, deep sea sediments, ice cores, for example, to achieve the scientific goals of the three transects. PAGES is not a funding agency and does not support research, but rather its function is to co-ordinate and facilitate and promote research on a larger scale than any one country or funding agency can support and on topics that go beyond the expertise of any one group of scientists.
Foraminifera and ostracodes across the Pliensbachian-Toarcian boundary in the Arctice Realm (stratigraphy, palaeobiogeography and biofacies)
Authors: Nikitenko Boris L. , Mickey Michael B.
Published: September 2007

The analysis of samples from numerous Pliensbachian and Toarcian sections from the northern regions of Russia and northern Alaska, as well as published data, allow us to estimate the correlative significance of foraminifera and ostracodes, and to develop an Arctic zonal standard based on these microfauna. During the Late Pliensbachian-Early Toarcian depositional period in the Arctic Basin and northwestern seas of Western Europe, a succession of almost simultaneous biotic and abiotic events occurred: widespread development of black bituminous shale at the beginning of the Early Toarcian, and a microbiota crisis (mass extinction event) in the Northern Hemisphere. The Early Toarcian microbiotic crisis was very sharp in both Arctic and Western European palaeobasins. In the Arctic seas, the generic and family composition of ostracode communities was completely replaced by new taxa. The species composition of foraminiferal assemblages changed considerably, while the generic composition of the foraminifera is only characterized by partial changes. In the Western European seas, the Early Toarcian microbenthos crisis caused taxonomic changes generally at the species level among foraminifera and at the generic level among ostracodes. The comprehensive analysis of the biogeographical distribution of Late Pliensbachian and Early Toarcian foraminifera and ostracodes, as well as Jaccard cluster analysis, allow us to define several biogeographical units within the Arctic and Boreal-Atlantic realms. A pattern of ecological distribution of microbenthos in bathymetric zones in Siberian palaeobasins has been developed, providing the basis for palaeoenvironmental reconstructions.
The mid-Cenomanian non-sequence: a micropalaeontological detective story
Authors: Hart Malcolm B.
Published: September 2007

The mid-Cenomanian non-sequence is described in terms of its stratigraphical position, regional impact and importance in Cenomanian stratigraphy. After its discovery in the site investigation for the Channel Tunnel and its location within the chalk succession of the Dover-Sangatte area, it has been traced throughout the United Kingdom and northern France. In stratigraphically complete successions it is coincident with the base of the
Rotalipora cushmani
Taxon Range Zone, although in many areas there is a major hiatus (= sequence boundary?) at this level. In more marginal successions, the non-sequence is characterized by the presence of reworked, phosphatized macrofossil assemblages in which the actual date of deposition can only be determined by the non-phosphatized macrofaunal elements or the microfossils extracted from the enclosing sediments. In Dorset/Devon and northern France the Cenomanian successions are condensed, and horizons with reworked macrofaunas have been investigated using a variety of micropalaeontological techniques (thin-sections, processed residues, acid reductions, etc.). In these areas the mid-Cenomanian non-sequence becomes one of the most important features of the succession and marks a major hiatus in many localities.
Dinoflagellate cyst record of the deep-sea Cretaceous-Tertiary boundary at Uzgruň, Carpathian Mountains, Czech Republic
Authors: Gedl Przemysław
Published: September 2007

The record of organic-walled dinoflagellate cysts in deep-sea facies across the Cretaceous-Tertiary boundary is poorly known. A detailed study of uppermost Maastrichtian-lowermost Danian Tethyan deep-sea flysch sediments deposited below the carbonate compensation depth at Uzgruň, in the Czech Republic, has yielded numerous and relatively well-preserved dinoflagellate cysts. Their distribution allows the Cretaceous-Tertiary boundary to be placed within a 73 cm interval, within which an iridium anomaly occurs. Assemblages show no major shifts within the boundary interval, but gradual changes were recorded that possibly relate to sea-level fluctuations and/or nutrient availability. High concentrations of peridinioids appear to indicate upwelling in this part of the Tethys near the Cretaceous-Tertiary boundary. The presence of thermophilic dinoflagellate cysts throughout the section points to a stable, warm-temperate to subtropical climate during the latest Maastrichtian and earliest Danian. Events, such as the
Areoligera
sp. acme,
Manumiella seelandica
acme and the
Spinidinium
sp. acme, known from other Cretaceous-Tertiary boundary sections around the world, were recognized within the studied material.
Mid-Pleistocene revolution and the ‘eccentricity myth’
Authors: Maslin Mark A. , Ridgwell Andy J.
Published: September 2007

The mid-Pleistocene revolution (MPR) is the term used to describe the transition between 41 ka and 100 ka glacial-interglacial cycles which occurred about one million years ago. Despite eccentricity having by far the weakest influence on insolation received at the Earth’s surface of any of the orbital parameters, it is often assumed to be the primary driver of the post-MPR 100 ka climate cycles. The traditional solution to this is to call for a highly nonlinear response by the global climate system to eccentricity. This ‘eccentricity myth’ is a simplified view of the relationship between global climate and orbital forcing and is in part due to an artefact of spectral analysis. Our aim here is to clarify the often confused role of eccentricity and review current theories of the MPR. We suggest that the post-MPR ‘100 ka’ glacial-interglacial cycles are more closely linked to precession, with the saw-toothed climate cycles being defined by every four or five precessional cycle. Because control over the number of precessional cycles involved is determined by eccentricity, eccentricity at most paces rather than drives the system. If true, then one must also question whether the MPR, itself defined by an abrupt change in spectral characteristics, is not also somewhat misconceived.
A late Early Pleistocene tephrochronological and pollen record from Auckland, New Zealand
Authors: Byrami M. L. , Newnham R. M. , Alloway B. V. , Pillans B. , Ogden J. , Westgate J. , Mildenhall D. C.
Published: September 2007

A late Early Pleistocene pollen record was obtained from a coastal site in Auckland, New Zealand. A combination of isothermal plateau fission track ages on interbedded tephras, palaeomagnetism, palynostratigraphy and orbital tuning to the marine oxygen isotope record of Ocean Drilling Program Site 677 constrained the age of the topmost 28 m of sediments to
c.
1.4–1.0 Ma (Marine Isotope Stages (MIS) 45–28). For this interval a diverse pollen record consisting of mostly extant pollen types shows multiple compositional shifts from a
Nothofagus
-dominated to conifer-dominated regional vegetation. These shifts are broadly correlated to changes in the marine oxygen isotope record. The inferred climate was moist, temperate, stable, and cooler than at present, but never as cool as the last glacial maximum. A permanent increase in
Nothofagus
forest in the region after MIS 35 seems to be related to a long-term palaeoclimatic shift that probably included greater temperature extremes between warm and cool stages and decreases in humidity and increased seasonality during cool stages. Although the Patiki pollen record predates the mid-Pleistocene revolution by
c.
100 ka, the nature of climate change itself was already in transition, and becoming more similar to the climate regime experienced in northern New Zealand in the Late Pleistocene.
Response of the European mammalian fauna to the mid-Pleistocene transition
Authors: van Kolfschoten Thijs , Markova Anastasia K.
Published: September 2007

The end of the Early Pleistocene is intriguing particularly for mammalian palaeontologists. In Eurasia, this interval has a faunal turnover caused by both the evolution and migration of species. It is the time in which the famous end-Villafranchian ‘event’ takes place, a phenomenon characterized by a faunal turnover resulting mainly from the migration of larger mammals. The smaller mammal record reveals in particular an important radiation in medium-sized voles. Different
Microtus
species evolve rapidly from species of the genus
Allophaiomys
, and various lineages can be observed. This radiation finally leads to the diversity seen today.

In eastern Europe, particularly on the Russian Plain and the Taman Peninsula, a number of localities occur where faunal assemblages from well-dated stratigraphic sequences can be analysed. These assemblages show the mid-Pleistocene evolution of rodent faunas within eastern Europe. Identical and synchronous changes in the mammalian faunas are found in other parts of Europe. However, a fauna from Untermassfeld in Germany does not fit this general picture, and serious doubts about its published age must be considered.
Genomic Comparisons of Humans and Chimpanzees
Authors: Varki Ajit , Nelson David L.
Published: September 2007

The genome consists of the entire DNA present in the nucleus of the fertilized embryo, which is then duplicated in every cell in the body. A draft sequence of the chimpanzee genome is now available, providing opportunities to better understand genetic contributions to human evolution, development, and disease. Sequence differences from the human genome were confirmed to be ∼1% in areas that can be precisely aligned, representing ∼35 million single base-pair differences. Some 45 million nucleotides of insertions and deletions unique to each lineage were also discovered, making the actual difference between the two genomes ∼4%. We discuss the opportunities and challenges that arise from this information and the need for comparison with additional species, as well as population genetic studies. Finally, we present a few examples of interesting findings resulting from genome-wide analyses, candidate gene studies, and combined approaches, emphasizing the pros and cons of each approach.
Cellular and subcellular alternans in the canine left ventricle
Authors: Cordeiro Jonathan M. , Malone Jane E. , Di Diego José M. , Scornik Fabiana S. , Aistrup Gary L. , Antzelevitch Charles , Wasserstrom J. Andrew
Published: September 2007

Previous studies indicate that action potential duration (APD) alternans is initiated in the endocardial (END) and midmyocardial (MID) regions rather than the epicardium (EPI) in the canine left ventricle (LV). This study examines regional differences in the rate dependence of Ca2+ transient characteristics under conditions that give rise to APD and associated T wave alternans. The role of the sarcoplasmic reticulum (SR) was further evaluated by studying Ca2+ transient characteristics in myocytes isolated from neonates, where an organized SR is poorly developed. All studies were performed in cells and tissues isolated from the canine LV. Isolated canine ENDO, MID, and EPI LV myocytes were either field stimulated or voltage clamped, and Ca2+ transients were measured by confocal microscopy. In LV wedge preparations, increasing the basic cycle length (BCL) from 800 to 250 ms caused alternans to appear mainly in the ENDO and MID region; alternans were not observed in EPI under these conditions. Ca2+ transient alternans developed in response to rapid pacing, appearing in EPI cells at shorter BCL compared with MID and ENDO cells (BCL=428 ± 17 vs. 517 ± 29 and 514 ± 21, respectively, P < 0.05). Further increases in pacing rate resulted in the appearance of subcellular alternans of Ca2+ transient amplitude, which also appeared in EPI at shorter BCL than in ENDO and MID cells. Ca2+ transient alternans was not observed in neonate myocytes. We conclude that 1) there are distinct regional differences in the vulnerability to rate-dependent Ca2+ alternans in dog LV that may be related to regional differences in SR function and Ca2+ cycling; 2) the development of subcellular Ca2+ alternans suggests the presence of intracellular heterogeneities in Ca2+ cycling; and 3) the failure of neonatal cells to develop Ca2+ alternans provides further support that SR Ca2+ cycling is a major component in the development of these phenomena.
The role of baseline in the cutaneous vasoconstrictor responses during combined local and whole body cooling in humans
Authors: Hodges Gary J. , Kosiba Wojciech A. , Zhao Kun , Alvarez Guy E. , Johnson John M.
Published: September 2007

Previous work showed that local cooling (LC) attenuates the vasoconstrictor response to whole body cooling (WBC). We tested the extent to which this attenuation was due to the decreased baseline skin blood flow following LC. In eight subjects, skin blood flow was assessed using laser-Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was expressed as LDF divided by blood pressure. Subjects were dressed in water-perfused suits to control WBC. Four forearm sites were prepared with microdialysis fibers, local heating/cooling probe holders, and laser-Doppler probes. Three sites were locally cooled from 34 to 28°C, reducing CVC to 45.9 ± 3.9, 42 ± 3.9, and 44.5 ± 4.8% of baseline ( P < 0.05 vs. baseline; P > 0.05 among sites). At two sites, CVC was restored to precooling baseline levels with sodium nitroprusside (SNP) or isoproterenol (Iso), increasing CVC to 106.4 ± 12.4 and 98.9 ± 10.1% of baseline, respectively ( P > 0.05 vs. precooling). Whole body skin temperature, apart from the area of blood flow measurement, was reduced from 34 to 31°C. Relative to the original baseline, CVC decreased ( P < 0.05) by 44.9 ± 2.8 (control), 11.3 ± 2.4 (LC only), 29 ± 3.7 (SNP), and 45.8 ± 8.7% (Iso). The reductions at LC only and SNP sites were less than at control or Iso sites ( P < 0.05); the responses at those latter sites were not different ( P > 0.05), suggesting that the baseline change in CVC with LC is important in the attenuation of reflex vasoconstrictor responses to WBC.
VEGF Induces Tie2 Shedding via a Phosphoinositide 3-Kinase/Akt–Dependent Pathway to Modulate Tie2 Signaling
Authors: Findley Clarence M. , Cudmore Melissa J. , Ahmed Asif , Kontos Christopher D.
Published: September 2007

Objective—

Tie2 and its ligands, the angiopoietins (Ang), are required for embryonic and postnatal angiogenesis. Previous studies have demonstrated that Tie2 is proteolytically cleaved, resulting in the production of a 75-kDa soluble receptor fragment (sTie2). We investigated mechanisms responsible for Tie2 shedding and its effects on Tie2 signaling and endothelial cellular responses.

Methods and Results—

sTie2 bound both Ang1 and Ang2 and inhibited angiopoietin-mediated Tie2 phosphorylation and antiapoptosis. In human umbilical vein endothelial cells, Tie2 shedding was both constitutive and induced by treatment with PMA or vascular endothelial growth factor (VEGF). Constitutive and VEGF-inducible Tie2 shedding were mediated by PI3K/Akt and p38 MAPK. Tie2 shedding was blocked by pharmacological inhibitors of either PI3K or Akt as well as by overexpression of the lipid phosphatase PTEN. In contrast, sTie2 shedding was enhanced by overexpression of either dominant negative PTEN, which increased Akt phosphorylation, or constitutively active, myristoylated Akt.

Conclusions—

These findings demonstrate that VEGF regulates angiopoietin-Tie2 signaling by inducing proteolytic cleavage and shedding of Tie2 via a novel PI3K/Akt-dependent pathway. These results suggest a previously unrecognized mechanism by which VEGF may inhibit vascular stabilization to promote angiogenesis and vascular remodeling.