bluuebunny/crossref_metadata_2025 huggingface dataset:
Age and evolution of late Mesozoic metamorphic core complexes in southern Siberia and northern Mongolia
Authors: DONSKAYA T.V. , WINDLEY B.F. , MAZUKABZOV A.M. , KRöNER A. , SKLYAROV E.V. , GLADKOCHUB D.P. , PONOMARCHUK V.A. , BADARCH G. , REICHOW M.K. , HEGNER E.
Published: January 2008

Numerous Cretaceous metamorphic core complexes (MCCs) extend from Transbaikalia in Russia to northern Mongolia within the Central Asian Orogenic Belt. We investigated the Buteel and Zagan MCCs in detail. Shear sense indicators in mylonitized rocks show footwall-to-the-NW tectonic transport. Single zircon dating of footwall rocks in the Buteel MCC establishes the emplacement of granitoid orthogneiss precursors at 240–211 Ma, a felsic metavolcanic rock at 265.0 ± 1.2 Ma, a syenite at 265.5 ± 1.2 Ma and a metarhyolite of the pre-granitoid basement at 553.6 ± 2.9 Ma. A peralkaline granite intruding orthogneisses of the Zagan MCC has a new U–Pb zircon age of 151.6 ± 0.7 Ma.
40
Ar/
39
Ar ages of 133.5 ± 1.8 Ma of hornblende from amphibolite and 122.6 ± 1.8 Ma of biotite from mylonitized gabbro–dolerite of the Buteel MCC are interpreted as cooling ages representing the time of deformation in the footwall. Geological data suggest that the MCCs in Transbaikalia and northern Mongolia formed as a result of extension in a crust that had previously been thickened by abundant calc-alkaline magmatism in an Andean-type setting on the border of the closing Mongol–Okhotsk ocean, by widespread collisional to post-collisional thrusting, and by extensive alkaline–peralkaline magmatism.
An analysis of Cotswold topography: insights into the landscape response to denudational isostasy
Authors: Lane N.F. , Watts A.B. , Farrant A.R.
Published: January 2008

We have used the NEXTMap Britain digital terrain model (DTM) to determine the lithospheric response to erosional unloading and the contribution of tectonics, in the form of elastic plate flexure, to the Cotswold ‘scarp and vale’ landscape. The calculations take into account lithology variations and along-strike changes in escarpment retreat. We show that flexural rock uplift as a result of erosional unloading varies spatially and may contribute up to 50% of the relief in the Cotswold region. This is supported by morphometric analysis, of concavity and steepness, for 66 longitudinal river profiles that drain the scarp and dip slope of the escarpment. Viscoelastic plate models suggest that the uplift is initially rapid (up to 8 m ka
−1
) and essentially complete within 50 ka. These initial rates are compatible with an early post-Anglian incision rate inferred from the Thames terraces. The ‘staircase’ terrace pattern suggests, however, that there have been a number of denudational isostatic events, each associated with a climate cycle. Finally, the analysis reveals an inherited ‘proto-landscape’ that has a subdued relief when compared with the modern DTM. Such a relief is consistent with an early extension of the River Thames, through the Vale of Moreton, to the north of the present-day Cotswold Hills.
Structure and U–Pb dating of the Saint-Arnac pluton and the Ansignan charnockite (Agly Massif): a cross-section from the upper to the middle crust of the Variscan Eastern Pyrenees
Authors: Olivier Philippe , Gleizes Gérard , Paquette Jean-Louis , Muñoz Sáez Carolina
Published: January 2008

In the Agly Massif (Pyrenees), two Variscan plutons, the Saint-Arnac pluton and the Ansignan charnockite, intrude different levels of a
c
. 10 km thick crustal section. The Saint-Arnac pluton intrudes through upper crustal rocks and the Ansignan charnockite cuts mid-crustal country-rocks. A structural study of these plutons based on the anisotropy of magnetic susceptibility technique, combined with a kinematic study of the country-rocks, shows that the structures and emplacement modes of the plutons are compatible with those of the other plutons of the Pyrenees emplaced during the D
2
transpressive phase. U–Pb dating on zircons from the Saint-Arnac pluton yields a 308.3 ± 1.2 Ma age for a diorite and a 303.6 ± 4.7 Ma age for a granodiorite. The charnockite was previously dated at 315 Ma. The emplacement ages of these two intrusions are thus separated by at least 5 Ma. First, numerous sills and laccoliths, such as the Ansignan laccolith, were injected in the middle crust, and this induced heating and thickening. Subsequently, the large Saint-Arnac pluton was injected in the upper crust at the beginning of formation of a gneissic dome.
Tectonic framework of the mud mounds, associated BSRs and submarine landslides, offshore Nicaragua Pacific margin
Authors: Talukder A.R. , Bialas J. , Klaeschen D. , Brueckmann W. , Reston T. , Petersen J.
Published: January 2008

The regional distribution of mounds, associated bottom-simulating reflectors (BSRs) and submarine landslides of the Pacific margin of Nicaragua suggests a genetic relationship between them. In the landslide-dominated parts of the margin, mud mounds occur in groups upslope behind the scarps and aligned parallel to the headwall. The morphotectonic features associated with the slides suggest that the slope failure could be triggered by slope oversteepening on the trailing flank of subducted seamounts. Geometric analysis of the faults triggering and controlling the mud mounds and associated BSRs also indicates that they were caused by collapses of the uplifted sea floor. Thus we propose a simple conceptual genetic model for the occurrences of the submarine landslides, surrounding mud mounds and associated BSRs in the area. Seamount subduction created locally higher fluid overpressure in the décollement. The uplift and fracturing of the margin wedge above the subducting seamount opened pathways for the overpressured fluid to escape, leading to the formation of numerous mud mounds on the sea floor and the BSR in the subsurface. The higher fluid supply locally reduced the shear strength of the sediments and facilitated failure of these sediments as landslides on the oversteepened slope caused by the subduction of the seamount.
Magmatic and tectonic evolution of the North Atlantic
Authors: Mjelde R. , Breivik A.J. , Raum T. , Mittelstaedt E. , Ito G. , Faleide J.I.
Published: January 2008

The primary aim of the present paper is (1) to review the tectonomagmatic evolution of the North Atlantic, and (2) constrain evolutionary models with new lithosphere strength estimates and interpretation of potential field data north of Iceland. Our interpretations suggest that the breakup along the entire eastern Jan Mayen Ridge occurred at
c
. 55 Ma. Calculations of lithospheric yield strength indicate that the continental rifting in East Greenland, which led to oceanic crustal formation west of the Jan Mayen Ridge at
c
. 25 Ma, could have started at
c
. 42.5 Ma. Symmetrical V-shaped gravimetric ridges, which can be traced back to
c
. 48 Ma, document large-scale asthenospheric flow both north and south of Iceland. Such flow is predicted by geodynamic models of mantle plumes, but has yet to be predicted by other mechanisms. The results from the compartments north of Iceland, viewed in a regional context, strengthen the hypothesis attributing the anomalous magmatism in the North Atlantic area from
c
. 70 Ma to the present to the Icelandic plume.
Late Pleistocene tephrochronology of marine sediments adjacent to Montserrat, Lesser Antilles volcanic arc
Authors: Le Friant A. , Lock E.J. , Hart M.B. , Boudon G. , Sparks R.S.J. , Leng M.J. , Smart C.W. , Komorowski J.C. , Deplus C. , Fisher J.K.
Published: January 2008

The recent history of the Soufrière Hills volcano, Montserrat, Lesser Antilles volcanic arc, is deduced using data obtained from a submarine core collected in 2002. The core contains concentrations of ash and several tephra layers, which are identified by the abundance of glass shards, dense and poorly vesiculated particles, and scoria. The tephra layers have been dated using micropalaeontology and stable isotope stratigraphy. Tephra layers in a marine sediment core off the coast of Montserrat record the volcanic history of South Soufrière Hills–Soufrière Hills volcano back to 250 ka. Eight layers are composed of dense juvenile ash related to dome eruptions, five of which can be directly correlated to dated domes or related pyroclastic flow sequences on land. Six layers are composed of pumiceous glassy ash and relate to significant explosive eruptions. A marker sequence of basalt tephra layers is dated at 124–147 ka and is correlated with construction of the South Soufrière Hills basaltic stratocone. Pelagic sediments between the main tephra layers have low abundances of volcanogenic components (<15%) and suggest long periods (
c
. 10
4
years) of dormancy or low activity.
Use of NanoSIMS in the search for early life on Earth: ambient inclusion trails in a
c
. 3400 Ma sandstone
Authors: WACEY DAVID , KILBURN MATT R. , MCLOUGHLIN NICOLA , PARNELL JOHN , STOAKES CRISPIN A. , GROVENOR CHRIS R.M. , BRASIER MARTIN D.
Published: January 2008

Ambient inclusion trails (AIT) are enigmatic microtubular structures created by the migration of mineral crystals through a lithified substrate. The decomposition of organic material has been suggested as the driving force for the crystal migration, but has yet to be rigorously tested. AIT may hold potential as a biosignature for investigating early life on Earth if the associated organic material can be shown to be biological. This paper attempts to test the formation mechanism and biogenicity of AIT from the
c
. 3400 Ma Strelley Pool sandstone of Western Australia using NanoSIMS technology. In doing so, we demonstrate the unique ability of the NanoSIMS to combine sub-micron scale imaging with
in situ
chemical and isotopic data, thereby enhancing our ability to evaluate the biogenicity criteria for Archaean microstructures. Enrichments of a suite of major elements (C, N, P, S) and trace elements (Co, Fe, Ni, Zn), often associated with biological processes, are found within several AIT in this sandstone. C and N enrichments are most common along AIT margins, and correlate with depletions of Si, O, Ca and Mg, indicating that this material is indeed organic in nature. δ
13
C values of this carbonaceous material average −26‰. Petrographic observations show that some of the AIT occur in the centre of detrital sandstone grains where they were sealed from later fluid flow and therefore preserve primary Archaean (bio)geochemistry. In contrast, AIT found around the outer edges of sandstone grains may contain more recent organic material introduced by later fluid migration and are an unreliable biosignature. Using the petrographic and geochemical data a multi-stage model for AIT formation and subsequent diagenetic modification is proposed. The possible sources of the primary organic material are discussed and we conclude that the data are consistent with a biological origin for these AIT. An abiogenic origin is more difficult to sustain but cannot yet be completely excluded for AIT in general.
Scent of a myth: tectonics, geochemistry and geomythology at Delphi (Greece)
Authors: Piccardi Luigi , Monti Cassandra , Vaselli Orlando , Tassi Franco , Gaki-Papanastassiou Kalliopi , Papanastassiou Dimitris
Published: January 2008

Extensive geochemical investigation (of water, travertine, soil and diffuse gas), coupled with geo-structural analysis, provides new insights into local fault–fluid interaction and allows us to pinpoint basic elements in the geological origin (or geomythology) of the Delphic Oracle, still debated by geologists. Delphi hosted the most famous oracle of antiquity, supposed to prophesy under the effects of intoxicating gas exhaling from a chasm in the ground. CO
2
–H
2
S-rich, ethylene-rich or CH
4
-rich gases have been invoked to explain the mantic vapours. Although previous interpretations dismissed the results achieved by classical scholars, this study fits together history, archaeology, mythology and geology in a single coherent frame. We highlight that no hydrocarbon gas discharges are released at present to the surface in the area. The lack of any geochemical ‘anomaly’ indicates that the Delphi active fault does not at present constitute a preferential route for the circulation of thermogenic deep fluids. The mythological gas-exhaling chasm can plausibly be related to episodic seismic ruptures in the ancient past, which affected for a limited time gas pockets fed by a relatively deep confined hydrothermal system. The Delphi fault has produced shocks up to Ms=6.7 (1 August 1870), and similar seismic faulting events in the past could have episodically triggered CO
2
–H
2
S-rich emissions.
New age constraints for the Ordovician Tyrone Volcanic Group, Northern Ireland
Authors: COOPER M.R. , CROWLEY Q.G. , RUSHTON A.W.A.
Published: January 2008

New biostratigraphical evidence and a high-precision isotope dilution thermal ionization mass spectrometry U–Pb zircon age provide refined age constraint for the Ordovician Tyrone Volcanic Group of the Tyrone Igneous Complex. In a graptolite fauna from Slieve Gallion, the presence of
Isograptus victoriae lunatus
, the index fossil of the
victoriae lunatus
graptolite zone, indicates a correlation with the Australasian Castlemainian (Ca1) Stage. The U–Pb zircon age of 473 ± 0.8 Ma dates a volcanic arc-related rhyolite body that is stratigraphically below graptolitic mudstones of Slieve Gallion. The U–Pb isotopic and biostratigraphical age constraints closely match an interpolated age for the base of the Middle Ordovician and indicate a Whitlandian age for the upper Tyrone Volcanic Group, which supports the regional correlation with the Ballantrae Complex, Midland Valley Terrane, Scotland.
The brittle evolution of a major strike-slip fault associated with granite emplacement: a case study of the Leannan Fault, NW Ireland
Authors: Kirkland C.L. , Alsop G.I. , Prave A.R.
Published: January 2008

NE–SW-trending sinistral strike-slip deformation is widespread throughout the Highlands of Scotland and NW Ireland and has been interpreted as a response to the subduction of Iapetus and continental collision. The southwestern continuation of the Great Glen Fault zone is marked in NW Ireland by the Leannan Fault. Field evidence derived from the Tullagh Point Granite indicates its intrusion along the fault during ductile sinistral shearing. U–Th–Pb zircon geochronology yields a crystallization age of 422 ± 2 Ma for this granite. Detailed analysis of fracture patterns throughout the Malin Head region demonstrates that sinistral fractures (F
1
) developed at an acute angle to the main fault strands. These fractures display oblique internal alignment of K-feldspar and are overprinted by dilatational quartz-filled joints at a similar orientation. The trend of these joints is consistent with
c
. 90° rotation of the σ
1
axes relative to F
1
as a result of intrusion of the Malin Head Granite dated at 412 ± 3 Ma. Subsequent sinistral fractures developed after dissipation of granite-related forces. They define an anticlockwise rotation of the regional σ
1
and moved under a different stress tensor from F
1
. It is concluded that the Leannan Fault moved sinistrally at
c
. 422 Ma and after
c
. 412 Ma, and that granite emplacement had pronounced effects on the fault kinematics.
Estimating hinterland exhumation from late orogenic basin volume, NW Borneo
Authors: MORLEY CHRIS K. , BACK STEFAN
Published: January 2008

A new approach for restoring sediment volumes onto the sediment source area to estimate uplift timing and magnitude is discussed and used in the context of late Tertiary basin and topographic development in NW Borneo. Sediment volumes for the Baram Deltaic Province were estimated for four time periods (latest Early, Middle and Late Miocene, and Pliocene–Recent), using 2D and 3D seismic horizons, wells and outcrops. Volume restoration onto the palaeo-sediment source area determined exhumation amount at the drainage divide (
c
. 5 km from 17 Ma to Recent) and provided a reasonable match with other denudation estimation methods (cooling ages and an older, regional sediment restoration study using 1979 vintage sediment isopach maps). Restoration took into account: (1) changing sediment densities during the erosion–deposition cycle; (2) changing area of the sediment source province with time (e.g. changing shoreline location as a result of eustacy, uplift and delta progradation, tectonic shortening); (3) uplift and partial erosion of Baram Deltaic Province sediment. Denudation at the drainage divide for the Middle Miocene, Late Miocene and Pliocene–Recent has proceeded at a similar rate for each period. Initial uplift of central Borneo has been attributed to buoyancy of thinned continental crust that jammed the subduction zone under NW Borneo in the Early Miocene. However, the absence of decay in the erosion rates with time from the Middle Miocene to Recent suggests operation of an additional uplift mechanism that may be related to delamination of mantle lithosphere; slab detachment is the favoured explanation.
Pre-eruption thermal rejuvenation and stirring of a partly crystalline rhyolite pluton revealed by the Earthquake Flat Pyroclastics deposits, New Zealand
Authors: MOLLOY CATHERINE , SHANE PHIL , NAIRN IAN
Published: January 2008

The Earthquake Flat Pyroclastics form a
c
. 10 km
3
rhyolite deposit erupted at
c
. 50 ka from the margin of Okataina Volcanic Centre, immediately following the caldera-forming eruption of the Rotoiti Pyroclastics (
c
. 100 km
3
) from vents
c
. 20 km to the NE. Earthquake Flat Pyroclastics deposits display textural and compositional complexity on a crystal-scale consistent with rejuvenation of a near-crystalline pluton in the upper crust. Quartz and plagioclase crystals are resorbed, whereas hornblende and biotite are euhedral. Fe–Ti oxides indicate large variations in pre-eruption temperatures (702–805 °C). Differences of up to 70 °C within pumice lapilli show that crystals were chaotically juxtaposed during magma stirring and evacuation. Chemical zoning within hornblende crystals is consistent with rimward increases of
c
. 50 °C. These features are consistent with a convective self-stirring process. Previous isotope studies demonstrate a long (>100 ka) crystallization history for the magma. Resorption of crystals deep in the magma may have produced a Ca-, Fe- and Mg-enriched rhyolite melt that allowed the growth of reverse-zoned hornblende. Microdiorite lithic fragments in the Earthquake Flat Pyroclastics and Rotoiti deposits and a basaltic eruption that immediately preceded the Rotoiti eruption suggest that mafic underplating beneath Okataina Volcanic Centre provided a major thermal and volatile pulse to drive the caldera eruptions.
Silicified
Horodyskia
and
Palaeopascichnus
from upper Ediacaran cherts in South China: tentative phylogenetic interpretation and implications for evolutionary stasis
Authors: DONG LIN , XIAO SHUHAI , SHEN BING , ZHOU CHUANMING
Published: January 2008

Horodyskia
is one of the earliest known macroscopic life forms, with a fossil record dating from
c
. 1.4 Ga.
Palaeopascichnus
represents a key Ediacaran element with world-wide distribution. However, their body constructions and affinities are poorly understood, partly because previously described species are mostly preserved as casts and moulds in siliciclastic rocks. Silicified specimens from the upper Ediacaran Liuchapo Formation in eastern Guizhou, South China, are described as
Horodyskia minor
sp. nov. and
Palaeopascichnus jiumenensis
sp. nov. Their taxonomic assignments are based on their uniserial arrangement of spheroidal or discoidal units, which are connected by a filament and surrounded by a quartz halo. They are unlikely to be brown algae, animal traces, faecal pellets, colonial metazoans, or giant sulphide-oxidizing bacteria. Instead, we propose that
Horodyskia
and
Palaeopascichnus
may be phylogenetically related, and their collective morphologies allow tentative comparison with agglutinated foraminifers: the segments can be compared with cytoplasm-filled chambers, connecting filament with small passage between chambers, and quartz haloes with agglutinated tests. However, their ontogeny appears to be distinct from that of modern foraminifers. The occurrences of
Horodyskia
fossils in Mesoproterozoic and Ediacaran rocks indicate an extremely long range (
c
. 900 Ma) and echoes the proposition of extended evolutionary stasis in the Proterozoic.
Hepatic Stellate Cells: Protean, Multifunctional, and Enigmatic Cells of the Liver
Authors: Friedman Scott L.
Published: January 2008

The hepatic stellate cell has surprised and engaged physiologists, pathologists, and hepatologists for over 130 years, yet clear evidence of its role in hepatic injury and fibrosis only emerged following the refinement of methods for its isolation and characterization. The paradigm in liver injury of activation of quiescent vitamin A-rich stellate cells into proliferative, contractile, and fibrogenic myofibroblasts has launched an era of astonishing progress in understanding the mechanistic basis of hepatic fibrosis progression and regression. But this simple paradigm has now yielded to a remarkably broad appreciation of the cell's functions not only in liver injury, but also in hepatic development, regeneration, xenobiotic responses, intermediary metabolism, and immunoregulation. Among the most exciting prospects is that stellate cells are essential for hepatic progenitor cell amplification and differentiation. Equally intriguing is the remarkable plasticity of stellate cells, not only in their variable intermediate filament phenotype, but also in their functions. Stellate cells can be viewed as the nexus in a complex sinusoidal milieu that requires tightly regulated autocrine and paracrine cross-talk, rapid responses to evolving extracellular matrix content, and exquisite responsiveness to the metabolic needs imposed by liver growth and repair. Moreover, roles vital to systemic homeostasis include their storage and mobilization of retinoids, their emerging capacity for antigen presentation and induction of tolerance, as well as their emerging relationship to bone marrow-derived cells. As interest in this cell type intensifies, more surprises and mysteries are sure to unfold that will ultimately benefit our understanding of liver physiology and the diagnosis and treatment of liver disease.
Amino Acid Transport Across Mammalian Intestinal and Renal Epithelia
Authors: Bröer Stefan
Published: January 2008

The transport of amino acids in kidney and intestine is critical for the supply of amino acids to all tissues and the homeostasis of plasma amino acid levels. This is illustrated by a number of inherited disorders affecting amino acid transport in epithelial cells, such as cystinuria, lysinuric protein intolerance, Hartnup disorder, iminoglycinuria, dicarboxylic aminoaciduria, and some other less well-described disturbances of amino acid transport. The identification of most epithelial amino acid transporters over the past 15 years allows the definition of these disorders at the molecular level and provides a clear picture of the functional cooperation between transporters in the apical and basolateral membranes of mammalian epithelial cells. Transport of amino acids across the apical membrane not only makes use of sodium-dependent symporters, but also uses the proton-motive force and the gradient of other amino acids to efficiently absorb amino acids from the lumen. In the basolateral membrane, antiporters cooperate with facilitators to release amino acids without depleting cells of valuable nutrients. With very few exceptions, individual amino acids are transported by more than one transporter, providing backup capacity for absorption in the case of mutational inactivation of a transport system.
Molecular Physiology of Preconditioning-Induced Brain Tolerance to Ischemia
Authors: Obrenovitch Tihomir Paul
Published: January 2008

Ischemic tolerance describes the adaptive biological response of cells and organs that is initiated by preconditioning (i.e., exposure to stressor of mild severity) and the associated period during which their resistance to ischemia is markedly increased. This topic is attracting much attention because preconditioning-induced ischemic tolerance is an effective experimental probe to understand how the brain protects itself. This review is focused on the molecular and related functional changes that are associated with, and may contribute to, brain ischemic tolerance. When the tolerant brain is subjected to ischemia, the resulting insult severity (i.e., residual blood flow, disruption of cellular transmembrane gradients) appears to be the same as in the naive brain, but the ensuing lesion is substantially reduced. This suggests that the adaptive changes in the tolerant brain may be primarily directed against postischemic and delayed processes that contribute to ischemic damage, but adaptive changes that are beneficial during the subsequent test insult cannot be ruled out. It has become clear that multiple effectors contribute to ischemic tolerance, including: 1) activation of fundamental cellular defense mechanisms such as antioxidant systems, heat shock proteins, and cell death/survival determinants; 2) responses at tissue level, especially reduced inflammatory responsiveness; and 3) a shift of the neuronal excitatory/inhibitory balance toward inhibition. Accordingly, an improved knowledge of preconditioning/ischemic tolerance should help us to identify neuroprotective strategies that are similar in nature to combination therapy, hence potentially capable of suppressing the multiple, parallel pathophysiological events that cause ischemic brain damage.
The Incidence of Placental Abnormalities, Maternal and Cord Plasma Malondialdehyde and Vascular Endothelial Growth Factor Levels in Women with Gestational Diabetes Mellitus and Nondiabetic Controls
Authors: Madazlı Rıza , Tuten Abdullah , Calay Zerrin , Uzun Hafize , Uludag Seyfettin , Ocak Vildan
Published: January 2008

Background/Aims: To evaluate the incidence of placental abnormalities, cord plasma erythropoietin (EPO) levels and nucleated red blood cell (NRBC) counts, maternal and cord plasma malondialdehyde (MDA) and vascular endothelial growth factor (VEGF) levels in women with gestational diabetes mellitus (GDM) and nondiabetic controls. Methods: Twenty-two women with GDM, diagnosed according to the current criteria of the American Diabetes Association, were compared with 22 controls. Maternal and cord blood and placental samples were obtained from all pregnant women. Cord plasma EPO levels and NRBC counts, maternal and cord plasma MDA and VEGF levels were determined. Placental tissues were examined histologically. Results: Maternal and cord plasma levels of MDA and cord plasma EPO levels and NRBC counts were significantly higher in GDM pregnancies (p < 0.01). The presence of villous immaturity, chorangiosis and ischemia were significantly increased in the placentas of women with GDM (p < 0.05). The maternal and cord plasma levels of MDA increased (p = 0.007 and p = 0.001, respectively), whereas VEGF decreased (p = 0.046 and p = 0.001, respectively) with the presence of villous immaturity. Conclusion: The complex process of villous development and maturity might be influenced by the maternal and fetal oxidative and angiogenetic milieu. The placenta that shows abnormalities in angiogenesis and maturation may lead to fetal hypoxia and compromise.
Oxidative Stress in Nonobese Women with Polycystic Ovary Syndrome: Correlations with Endocrine and Screening Parameters
Authors: Verit Fatma Ferda , Erel Ozcan
Published: January 2008

Aims: We investigated serum total oxidant status (TOS) and total antioxidant status (TAS) and whether oxidative stress is associated with endocrine and sonographic parameters in nonobese women with polycystic ovary syndrome (PCOS). Methods: Sixty-three nonobese normoinsulinemic PCOS women and 58 normoandrogenic ovulatory controls were enrolled in the study. Standard clinical examinations and ultrasonographic and endocrine screening including follicle-stimulating hormone, luteinizing hormone (LH), estradiol, progesterone, total testosterone, sex hormone-binding globulin and dehydroepiandrosterone sulfate (DHEAS) were performed. The insulin resistance was calculated by the measurement of fasting serum glucose and insulin levels, serum insulin response to an oral glucose tolerance test and homeostasis model assessment. TAS and TOS were assessed by automated colorimetric methods. Results: The women with PCOS had significantly higher TAS, TOS, LH, free androgen index and DHEAS levels. TAS, but not TOS, was positively correlated with LH, free androgen index and ovarian volume. However, there was no correlation between TAS and DHEAS. By multiple regression analysis, LH, TOS and ovarian volume were the independent variables that were associated with TAS. Conclusions: TAS was found to be increased in nonobese patients with PCOS, and this may account for some of the physiological changes.
Preoperative Predictors for Residual Tumor after Surgery in Patients with Ovarian Carcinoma
Authors: de Jong D. , Eijkemans M.J. , Lie Fong S. , Gerestein C.G. , Kooi G.S. , Baalbergen A. , van der Burg M.E.L. , Burger C.W. , Ansink A.C.
Published: January 2008

Objectives: Suboptimal debulking (>1 cm residual tumor) results in poor survival rates for patients with an advanced stage of ovarian cancer. The purpose of this study was to develop a prediction model, based on simple preoperative parameters, for patients with an advanced stage of ovarian cancer who are at risk of suboptimal cytoreduction despite maximal surgical effort. Methods: Retrospective analysis of 187 consecutive patients with a suspected clinical diagnosis of advanced-stage ovarian cancer undergoing upfront debulking between January 1998 and December 2003. Preoperative parameters were Karnofsky performance status, ascites and serum concentrations of CA 125, hemoglobin, albumin, LDH and blood platelets. The main outcome parameter was residual tumor >1 cm. Univariate and multivariate logistic regression was employed for testing possible prediction models. A clinically applicable graphic model (nomogram) for this prediction was to be developed. Results: Serum concentrations of CA 125 and blood platelets in the group with residual tumor >1 cm were higher in comparison to the optimally cytoreduced group (p < 0.0001 and <0.01, respectively). Serum albumin and hemoglobin levels were lower in the group with residual tumor (p < 0.0001 and <0.05, respectively). The frequency of preoperative ascites was higher in the group with residual tumor (p < 0.0005). The prediction model, consisting of CA 125 and albumin, for remaining with residual tumor showed an area under the receiver operating characteristics curve of 0.79. A nomogram for probability of residual tumor >1 cm based on serum levels of CA 125 and albumin was established. Conclusion: Postoperative residual tumor despite maximal surgical effort can be predicted by preoperative CA 125 and serum albumin levels. With a nomogram based on these two parameters, probability of postoperative residual tumor in each individual patient can be predicted. This proposed nomogram may be valuable in daily routine practice for counseling and to select treatment modality.
Pegylated Liposomal Doxorubicin in Recurrent Malignant Glioma: Analysis of a Case Series
Authors: Glas Martin , Koch Horst , Hirschmann Birgit , Jauch Tanja , Steinbrecher Andreas , Herrlinger Ulrich , Bogdahn Ulrich , Hau Peter
Published: January 2008

Background: Recurrent malignant glioma has a dismal prognosis, and therapeutic options are scarce. After previous potentially encouraging reports on liposomal pegylated doxorubicin (PEG-DOX) in this setting, PEG-DOX was applied to patients with recurrent malignant glioma in an institutional series. Methods: In a retrospective analysis, 49 patients with recurrent high-grade glioma (WHO III, n = 18; WHO IV, n = 31) were treated with PEG-DOX (days 1 and 14/28, 20 mg/m2, n = 26) alone or in combination with temozolomide (days 1–5/28, 200 mg/m2, n = 23). The response rate, progression-free survival and overall survival were evaluated. Results: The rate of progression-free patients at 6 months after initiation of therapy was 27% (WHO III, 33%; WHO IV, 23%). The median overall survival (mOS) after initiation of PEG-DOX (monotherapy and combination therapy) was 8 months (WHO III, 16 months; WHO IV, 7 months). The mOS after initiation of PEG-DOX monotherapy was 8 months, and after initiation of combination therapy, 10 months. Both regimens were well tolerated, with the main side effect being hematologic toxicity (grade 1–2, 8%; grade 3–4, 18%). Conclusion: These data demonstrate the safety and moderate efficacy of PEG-DOX ± temozolomide therapy in recurrent malignant glioma. The potential of this nonalkylating chemotherapy should be further explored.
Inhibition of Dermal MRSA Colonization by Microalgal Micro- and Nanoparticles
Authors: Lukowski G. , Lindequist U. , Mundt S. , Kramer A. , Jülich W.-D.
Published: January 2008

The aim of this study was to investigate the prevention of the dermal colonization of methicillin-resistant Staphylococcus aureus (MRSA) strains by the application of micro- and nanoparticles called Maresome™. Maresome™ were prepared from selected microalgae by a novel emulsion technique. They contain lipids and all other components of the microalgae in an encapsulated form. It could be shown that Maresome™ prepared from a cyanobacterial strain of the order Nostocales (Bio33-Maresome™) were able to inhibit the dermal colonization of different MRSA strains (North German Epidemic Strain, Col, N315) and even of the vancomycin-resistant strain MU50 in the models ‘mouse ear’ and ‘cow udder teat’. Pretreatment of the skin with Maresome™ reduced the number of attached MRSA by 3–4 log units in comparison to the control. We assume that a prophylactic skin care with Maresome™ could complete the multibarrier anti-infectious strategy against MRSA.
Angioleiomyoma Originating from the Ovary of an Eleven-Year-Old Premenarchal Girl
Authors: Hsu Tian-Lun , ChangChien Chan-Chao , Huang Chao-Cheng , Lin Hao
Published: January 2008

Background: Angioleiomyoma (ALM) is a rare, benign neoplasm involving the peripheral soft tissues. ALM has not previously been described to originate from the ovary. We present a case herein of a premenarchal girl with a large ALM originating from the ovary. Case: An 11-year-old girl underwent a laparotomy during the course of evaluation and treatment of a palpable, painless, abdominal mass. The mass was shown to have a strong blood flow by sonography. A solid mass left ovarian was identified and resected. The final pathologic report of the resected tumor was consistent with an ALM. Conclusion: To our knowledge, this is the first report of an ALM arising from the ovary. The treatment of choice for such an ovarian mass is surgical excision, which is usually a curative measure.
Heme Oxygenase-1 and Carbon Monoxide in Vascular Pathobiology
Authors: Dulak Jozef , Deshane Jessy , Jozkowicz Alicja , Agarwal Anupam
Published: January 2008

Angiogenesis involves the formation of new blood vessels and is critical for fundamental events such as development and repair after injury. Perturbances in angiogenesis contribute to the pathogenesis of diverse clinical conditions including cancer, complications of diabetes mellitus, ischemia/reperfusion injury of the heart and other organs, and preeclampsia, as well as a number of inflammatory disorders. Recent work has identified heme oxygenase-1 and its gaseous product, carbon monoxide, to possess potent proangiogenic properties in addition to well-recognized antiinflammatory, antioxidant, and antiapoptotic effects. Angiogenic factors, such as vascular endothelial growth factor and stromal cell–derived factor-1, mediate their proangiogenic effects through induction of heme oxygenase-1, making it an attractive target for therapeutic intervention. This review will provide an overview of the role of heme oxygenase-1 and carbon monoxide in angiogenesis.
Leonardo da Vinci and Perpetual Motion
Authors: Mills Allan A.
Published: January 2008

Leonardo da Vinci illustrated several traditional forms of “perpetual-motion machine” in small pocket books now known as the Codex Forster. He was well aware that these designs, based on waterwheel/pump combinations, mechanical overbalancing hammers or rolling balls, would not—and could not—work.
L'Arte dei “Romori”: Leonardine Devotion in Luigi Russolo's Oeuvre
Authors: Chessa Luciano
Published: January 2008

The author has discerned a deep interest in the occult arts at the core of Luigi Russolo's Art of Noises. Such an interest is confirmed by Russolo's admiration for Leonardo da Vinci. Leonardo's writings on music and acoustics constituted in fact a scientific and spiritual paradigm for Russolo; the former's mechanical musical-instrument projects were important models for Russolo's own, from 1913's intonarumori to the nuovo istrumento musicale a corde of 1931. Perhaps because of the futurists' ambivalent position toward the figure of Leonardo (proto-futurist or passatista), Russolo profusely quoted Leonardo but carefully avoided mentioning any borrowing.
The Proportional Consistency and Geometry of Leonardo's Giant Crossbow
Authors: Landrus Matthew
Published: January 2008

The traditional scholarly appraisal of Leonardo's Giant Crossbow design dismisses it as a fanciful object, although often with praise of it as a quintessential example of his technical draftsmanship. The author offers evidence of Leonardo's likely intent that the drawing function as a reliable plan with which readers of a treatise on military engineering could consider a strategy, or an imaginative solution (a fantasia), for building the full-scale giant crossbow. At issue are the agreements between the illustrated dimensions and the written specifications, the proportional consistency of those dimensions and the possible use of Archimedean geometry to determine the primary dimensions.
Parameters of Spike Trains Observed in a Short Time Window
Authors: Pawlas Zbyněk , Klebanov Lev B. , Prokop Martin , Lansky Petr
Published: January 2008

We study the estimation of statistical moments of interspike intervals based on observation of spike counts in many independent short time windows. This scenario corresponds to the situation in which a target neuron occurs. It receives information from many neurons and has to respond within a short time interval. The precision of the estimation procedures is examined. As the model for neuronal activity, two examples of stationary point processes are considered: renewal process and doubly stochastic Poisson process. Both moment and maximum likelihood estimators are investigated. Not only the mean but also the coefficient of variation is estimated. In accordance with our expectations, numerical studies confirm that the estimation of mean interspike interval is more reliable than the estimation of coefficient of variation. The error of estimation increases with increasing mean interspike interval, which is equivalent to decreasing the size of window (less events are observed in a window) and with decreasing the number of neurons (lower number of windows).
A Sparse Generative Model of V1 Simple Cells with Intrinsic Plasticity
Authors: Weber Cornelius , Triesch Jochen
Published: January 2008

Current models for learning feature detectors work on two timescales: on a fast timescale, the internal neurons' activations adapt to the current stimulus; on a slow timescale, the weights adapt to the statistics of the set of stimuli. Here we explore the adaptation of a neuron's intrinsic excitability, termed intrinsic plasticity, which occurs on a separate timescale. Here, a neuron maintains homeostasis of an exponentially distributed firing rate in a dynamic environment. We exploit this in the context of a generative model to impose sparse coding. With natural image input, localized edge detectors emerge as models of V1 simple cells. An intermediate timescale for the intrinsic plasticity parameters allows modeling aftereffects. In the tilt aftereffect, after a viewer adapts to a grid of a certain orientation, grids of a nearby orientation will be perceived as tilted away from the adapted orientation. Our results show that adapting the neurons' gain-parameter but not the threshold-parameter accounts for this effect. It occurs because neurons coding for the adapting stimulus attenuate their gain, while others increase it. Despite its simplicity and low maintenance, the intrinsic plasticity model accounts for more experimental details than previous models without this mechanism.
Foreigners' Impact on European Societies
Authors: Semyonov Moshe , Raijman Rebeca , Gorodzeisky Anastasia
Published: January 2008

The research examines the extent to which attitudes toward foreigners vary across European countries. Using data from the European Social Survey for 21 countries the analysis reveals that foreigners' impact on society is viewed in most countries in negative rather in positive terms. The negative views are most pronounced with regard to foreigners' impact on crime and least pronounced with regard to foreigners' impact on culture. Multi-level regression analysis demonstrates that the negative views tend to be more pronounced among individuals who are socially and economically vulnerable and among individuals who hold conservative political ideologies. The analysis also reveals that negative attitudes toward foreigners tend to be more pronounced in countries characterized by large proportions of foreigners, where economic conditions are less prosperous, and where support for right-wing political parties is more prevalent. The analysis shows that inflated perception of the size of the foreign population is likely to increase negative views toward foreigners and to mediate the relations between actual size and attitudes toward foreigners' impact on society. The findings are presented and discussed in light of sociological theories on individuals and structural sources of public attitudes toward out-group populations and on the role of perceptions in shaping such attitudes.
An Index of Pro-Woman Nation-States
Authors: Wernet Christine A.
Published: January 2008

Pro-woman nation-states need to be identified because these states may help diminish traditional gender roles and gender stratification by providing structural opportunities for women (Wang, 2004; Wernet et al., 2005). Comparative, country-level data on multiple domains, such as female life expectancy, low fertility rates, education levels, the legal status of abortion, the percent of women in public life, female labor force participation, and family leave policies, are gathered from the Population Reference Bureau (1998) and the International Labor Organization (1997). This article explores the differential access that people in 39 countries have to the aforementioned rights and privileges in order to identify which countries have policies that are the most beneficial for women by ranking pro-woman nation-states in a comparative index.
Meritocracy and Elitism in a Global City: Ideological Shifts in Singapore
Authors: Tan Kenneth Paul
Published: January 2008

The concept of meritocracy is unstable as its constituent ideas are potentially contradictory. The egalitarian aspects of meritocracy, for example, can come into conflict with its focus on talent allocation, competition, and reward. In practice, meritocracy is often transformed into an ideology of inequality and elitism. In Singapore, meritocracy has been the main ideological resource for justifying authoritarian government and its pro-capitalist orientations. Through competitive scholarships, stringent selection criteria for party candidacy, and high ministerial salaries, the ruling People's Action Party has been able to co-opt talent to form a “technocratic” government for an “administrative state.” However, as Singapore becomes more embedded in the processes of globalization, it will experience new forms of national crisis, alternative worldviews through global communications technology, and a widening income gap, all of which will force its ideology of meritocracy to unravel.
Democracy and Floating Exchange Rates
Authors: Hall Michael
Published: January 2008

A number of articles in the past few years have found that democracies are more likely to commit to a floating exchange rate regime. I argue that we do not have a solid understanding of the causal mechanism that explains why democracies would float more often. I test a variety of hypotheses to explore exactly what features of democratic practice might account for the propensity to declare a float, using two different datasets. While the tests are not conclusive, they suggest that the number of veto players or the regular use of open, competitive elections may influence exchange rate commitments.
The Politics of Emotion in British Asian Experiences of Bombay Cinema
Authors: Jha Meeta Rani
Published: January 2008

British Asian subjects articulate their emotional and embodied engagement with Bombay cinema,1 making visible glimpses of their social life. This article scrutinizes the Bombay cinema experience through a sociological, empirical and ethnographic analysis of 24 semi–structured interviews undertaken in London, Manchester and Oldham. I employ the ‘circuit of culture model’ (du Gay et al. 1997; Johnson 1986) to explore the relations between the processes of production, representation, reception and regulation in the diasporic circulation of Bombay cinema. The ambiguous and ambivalent, but clear polarities that define the respondents’ relations with the cinema articulate a dialectical dynamism of affect and criticism. Combining the ‘keeping in touch with back home’ discourses of earlier South Asian generations with other desires of ‘recognition’, ‘visibility’, ‘consumption’ and ‘drudgery of culture’, they convey their understanding of themselves and their world. Some respondents were reflexive about their complicity in the dominant ideologies, and the holding together of the contradictions enabled discussion and debates. The desire for ‘glimpses of ourselves’ is full of contradictions in a neo–liberal global culture, and Bombay cinema practice becomes a site for the postcolonial diasporic imagining of identity. I argue that the contradictory and ambivalent identifications in Bombay cinema experiences are reconfigured to desire a decolonized subjectivity where an inter–subjective sensibility is valued through a prioritizing of an emotional connection and relationality. This, I propose is a critique of Western liberal notions of ‘individual self formation.’
Pantomime Terror
Authors: Hutnyk John
Published: January 2008

I find it increasingly problematic to write analytically about ‘diaspora and music’ at a time of war. It seems inconsequential; the culture industry is not much more than a distraction; a fairytale diversion to make us forget a more sinister amnesia behind the stories we tell. This article nonetheless takes up debates about cultural expression in the field of diasporic musics in Britain. It examines instances of creative engagement with, and destabilization of, music genres by Fundamental and Asian Dub Foundation, and it takes a broadly culture critique perspective on diasporic creativity as a guide to thinking about the politics of hip-hop in a time of war. Examples from music industry and media reportage of the work of these two bands pose both political provocation and a challenge to the seemingly unruffled facade of British civil society, particularly insofar as musical work might still be relevant to struggles around race and war. Here, at a time of what conservative critics call a ‘clash of civilizations’, I examine how music and authenticity become the core parameters for a limited and largely one-sided argument that seems to side-step political context in favour of sensationalized—entrenched—identities and a mythic, perhaps unworkable, ideal of cultural harmony that praises the most asinine versions of multiculturalism while demonizing those most able to bring it about. Here the idea that musical cultures are variously authentic, possessive or coherent must be questioned when issues of death and destruction are central, but ignored.