bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drosophila melanogaster-Based Screening for Multihost Virulence Factors ofPseudomonas aeruginosaPA14 and Identification of a Virulence-Attenuating Factor, HudA
Authors: Kim Seol-Hee , Park Shin-Young , Heo Yun-Jeong , Cho You-Hee 
Published: July 2008

ABSTRACTPseudomonas aeruginosais an important opportunistic human pathogen that interacts with phylogenetically diverse nonmammalian hosts, including plants, nematodes, and insects. Here, we exploited theP. aeruginosa-induced killing of the fruit flyDrosophila melanogasteras an assay system to screen for virulence-attenuated mutants ofP. aeruginosaPA14. Fifteen nonredundant mutants were isolated from 4,018 random transposon (TnphoA) insertion clones, and 13 out of them (86.7%) displayed significantly reduced virulence in a murine peritonitis model as well. The TnphoAinsertion sites of the 15 mutants were determined; already known virulence genes (dsbA,pvdI,fhlB,pilF, andwspF) and new virulence genes such as PA0253 (hudR), PA0369, PA2077, PA0272, PA2113, PA2965 (fabF1), and PA2002 were identified; one insertion was located at the intergenic region between PA1928 and PA1929; and the other two insertions were located in the genes (PA14_35740 and PA14_36000) within a putative genomic island, indicating a potential pathogenicity island of PA14. Further characterization ofhudR, a virulence gene which encodes a MarR/SlyA family transcription factor, revealed that elevated expression of PA0254 (hudA[homologous toUbiD]) was necessary and sufficient for the virulence attenuation of thehudRmutant. The HudR protein repressed thehudARoperon by directly binding to its upstream promoter region. Collectively, these results validate the relevance of theD. melanogastermodel for the high-throughput identification of new virulence factors involved in the multihost pathogenesis ofP. aeruginosa.
HEDGING UNDER THE HESTON MODEL WITH JUMP-TO-DEFAULT
Authors: CARR PETER , SCHOUTENS WIM 
Published: July 2008

In this paper, we will explain how to perfectly hedge under Heston's stochastic volatility model with jump-to-default, which is in itself a generalization of the Merton jump-to-default model and a special case of the Heston model with jumps. The hedging instruments we use to build the hedge will be as usual the stock and the bond, but also the Variance Swap (VS) and a Credit Default Swap (CDS). These instruments are very natural choices in this setting as the VS hedges against changes in the instantaneous variance rate, while the CDS protects against the occurrence of the default event. First, we explain how to perfectly hedge a power payoff under the Heston model with jump-to-default. These theoretical payoffs play an important role later on in the hedging of payoffs which are more liquid in practice such as vanilla options. After showing how to hedge the power payoffs, we show how to hedge newly introduced Gamma payoffs and Dirac payoffs, before turning to the hedge for the vanillas. The approach is inspired by the Post–Widder formula for real inversion of Laplace transforms. Finally, we will also show how power payoffs can readily be used to approximate any payoff only depending on the value of the underlier at maturity. Here, the theory of orthogonal polynomials comes into play and the technique is illustrated by replicating the payoff of a vanilla call option.
Frictional-viscous flow, seismicity and the geology of weak faults: a review and future directions
Authors: Imber J. , Holdsworth R. E. , Smith S. A. F. , Jefferies S. P. , Collettini C. 
Published: July 2008

Abstract
Previously hypothesized fault weakening mechanisms include faults lined by low-friction clay gouges, elevated pore pressures within fault cores and/or the operation of dynamic weakening during seismic slip. Geological studies to support dynamic weakening are still in their infancy and there is little geological evidence for the widespread occurrence of low-friction gouges. The cores of some ancient faults exhumed from <5 km depth contain sheared syntectonic mineral veins. This observation is consistent with elevated pore pressures, but the implications for long-term fault weakening are unclear. Experimental data and microphysical modelling suggest that frictional–viscous flow within phyllosilicate-rich fault rocks (phyllonites, some foliated cataclasites) can cause sufficient weakening of crustal faults to satisfy published heat flow constraints. These predictions are consistent with the common occurrence of phyllonite in the cores of large-displacement faults exhumed from >5 km depth. Comparison with seismological data suggests that some faults with phyllonitic cores are likely to generate large earthquakes. Future studies should establish the geological evidence for seismic slip within phyllonitic fault cores and quantify the partitioning between seismic slip and frictional–viscous flow. Further geological observations are also required to test the hypothesized mechanisms by which earthquakes can nucleate and propagate along phyllosilicate-rich faults.
Fault weakening due to CO
2
degassing in the Northern Apennines: short- and long-term processes
Authors: Collettini C. , Cardellini C. , Chiodini G. , De Paola N. , Holdsworth R. E. , Smith S. A. F. 
Published: July 2008

Abstract

The influx of fluids into fault zones can trigger two main types of weakening process that operate over different timescales and facilitate fault movement and earthquake nucleation. Short- and long-term weakening mechanisms along faults require a continuous fluid supply near the base of the brittle crust, a condition satisfied in the extended/extending area of the Northern Apennines of Italy. Here carbon mass balance calculations, coupling aquifer geochemistry to isotopic and hydrological data, define the presence of a large flux (
c
. 12 160 t/day) of deep-seated CO
2
centred in the extended sector of the area. In the currently active extending area, CO
2
fluid overpressures at ∼85% of the lithostatic load have been documented in two deep (4–5 km) boreholes. In the long-term, field studies on an exhumed regional low-angle normal fault show that, during the entire fault history, fluids reacted with fine-grained cataclasites in the fault core to produce aggregates of weak, phyllosilicate-rich fault rocks that deform by fluid assisted frictional–viscous creep at sub-Byerlee friction values (μ<0.3). In the short term, fluids can be stored in structural traps, such as beneath mature faults, and stratigraphical traps such as Triassic evaporites. Both examples preserve evidence for multiple episodes of hydrofracturing induced by short-term cycles of fluid pressure build-up and release. Geochemical data on the regional-scale CO
2
degassing process can therefore be related to field observations on fluid rock interactions to provide new insights into the deformation processes responsible for active seismicity in the Northern Apennines.
Deformation partitioning within a sinistral transpression zone along the southwestern margin of the Tauern Window (eastern Alps)
Authors: Wölfler Andreas , Rabitsch Robert , Fritz Harald , Gaich Heiko , Kurz Walter , Reiter Angelika 
Published: July 2008

Abstract
This study is concerned with a newly recognized structure at the southwestern border of the Tauern Window and the neighbouring Austroalpine basement rocks, the Lappach Structure. Structural and isotopic investigations show that this structure is the result of sinistral transpression and backthrusting along the Austroalpine–Penninic contact. Deformation partitioning and differential exhumation of crustal wedges is documented by a succession of ductile and brittle deformation stages. Two stages are distinguished: (1) up-doming of Penninic units and associated advective heat transfer caused a strong temperature variation with the highest temperatures in central portions of the Tauern Window. Coeval transpression with distributed sinistral shear formed high-temperature, partly annealed fabrics in central portions and lower-temperature fabrics with strong crystallographic preferred orientation of quartz along the Tauern Window margin. Southward decrease of temperatures was matched by increases in stress and deformation intensity. (2) Progressive cooling was accompanied by shear localization, deformation partitioning and fluid infiltration. Overall sinistral shear resolved in a discrete strike slip–fault and south vergent folds with associated thrusts defining a backthrust zone along the southern Tauern margin. Southwards extrusion disturbed previously established palaeo-isogrades and juxtaposed rocks from greater depths against lower-grade metamorphic units. Fluids penetrated faults, reduced shear strength and contributed to shear localization.
Fluid flow properties of basin-bounding normal faults in platform carbonates, Fucino Basin, central Italy
Authors: Agosta Fabrizio 
Published: July 2008

Abstract

Both structural and petrophysical (porosity, ϕ, and permeability,
k
) data show that the basin-bounding normal faults of the Fucino Basin, central Italy, have a combined barrier–conduit effect on fluid flow. The deformed carbonates comprise fault cores of both matrix- and cement-supported fault rocks (low ϕ and
k
) and major slip surfaces, and damage zones of fragmented and pulverized carbonates (high ϕ and
k
) and small faults. The host rocks are Mesozoic, platform-related boundstones with low ϕ (<1%) and low
k
(<1×10
−4
mD). The results of ultrasonic analysis suggest that the fragmented carbonates contain pores with a high aspect ratio, whereas the fault rocks have pores with a low aspect ratio and some moldic porosity. These two separate fluid units are modelled as an elastic cracked medium (fragmented carbonates), and as a granular medium (fault core). By using well-known correlations, their permeability is then computed from known values of ϕ, pore radii and elastic moduli.
40
Ar/
39
Ar dating of synkinematic white mica: insights from fluid-rock reaction in low-grade shear zones (Mont Blanc Massif) and constraints on timing of deformation in the NW external Alps
Authors: Rolland Y. , Rossi M. , Cox S. F. , Corsini M. , Mancktelow N. , Pennacchioni G. , Fornari M. , Boullier A. M. 
Published: July 2008

Abstract

This paper highlights the use of synkinematic white mica, biotite and phlogopite for the dating of deformation in ductile shear zones within crystalline rocks under low-grade metamorphic conditions. The Mont Blanc shear zones range from 1 mm to 50 m in width and have localized intense fluid flow, resulting in substantial differences in mineralogy and whole-rock geochemistry. On the basis of their synkinematic alteration assemblages and geographic distribution within the Mont Blanc Massif, three main metamorphic zones are distinguished within the network of shear zones. These are: (i) epidote±white mica-bearing assemblages; (ii) chlorite–phlogopite-bearing assemblages; and (iii) white mica±biotite±calcite±actinolite±epidote- bearing assemblages.
40
Ar/
39
Ar age spectra of biotite and phlogopite are complex, and reflect significant variations in chemical composition. In biotite, this is partly due to inheritance from precursor Variscan magmatic biotite. In contrast, new white mica grew at the expense of feldspar during Alpine deformation and its Ar spectra do not show any excess
40
Ar. On the SE side of Mont Blanc, ages of shear zone phengites have a narrow range of 15.8–16.0±0.2 Ma, which is in the same age range as
40
Ar/
39
Ar ages of minerals from kinematically related veins. The top-to-SE sense of shear is consistent with initiation of a Mont Blanc flower-structure within a dextral transpressional system by 16 Ma. On the NW side, mini-plateaux ages of 14.5±0.3 and 23.4±0.4 Ma are preserved in the same sample, suggesting the possibility of two phases of deformation. This is also supported by partly preserved ages of 18–36.6 Ma in biotites and phlogopites. Ages between 36 and 18 Ma might reflect ongoing top-to-NW thrusting, following Penninic Front activation, in a context of nappe stacking and crustal thickening. NW-directed thrusting on the NW side of Mont Blanc continued after 18 Ma, synchronous with SE-directed thrusting on the SE side of the massif. These divergent movements produced the overall pop-up geometry of the Mont Blanc Massif, which may correspond to a positive flower structure developed within a zone of regional dextral transpression extending SW from the Rhone valley into the Mont Blanc area.
Assessment of thermal circulations in strike-slip fault systems: the Terme di Valdieri case (Italian western Alps)
Authors: Baietto A. , Cadoppi P. , Martinotti G. , Perello P. , Perrochet P. , Vuataz F.-D. 
Published: July 2008

Abstract

Individual faults, faults linking at depth in flower structure zones and jogs bounded by faults are common structural elements in strike–slip fault systems and can play an important role in controlling thermal fluid flows. This paper explores the influence of these structures on the thermal circulations and fluid outflows of Terme di Valdieri, in the crystalline basement of the Argentera Massif (western Alps). In this site, thermal waters upwell at the tip of a NW-trending right-lateral fault, but exactly which structures control infiltration of meteoric waters and deep circulation is not clear from field surveys. Three-dimensional thermohydraulic numerical models calculated in steady-state and in transient regimes are presented for three alternative hypotheses. These account for circulations occurring: (i) within a single fault and adjoining host rocks; (ii) in faults intersecting at depth; and (iii) in faults interacting by means of a permeable step-over. The simulations show that advective flows can coexist with convective flows in models (i) and (iii), provided that the fault permeabilities are higher than 2×10
−13
m
2
, while advection prevails in model (ii) at all values of permeability. Model (iii) achieves the best fit to the data under the assumption of advective and convective flows. This finding provides a first quantitative estimate of the importance of jog structures bounded by strike–slip faults in favouring thermal outflows. Moreover, the numerical results suggest that thermal convection can coexist with advection also in mountainous settings.
The influence of layering and pre-existing joints on the development of internal structure in normal fault zones: the Lodève basin, France
Authors: van der Zee Wouter , Wibberley Christopher A. J. , Urai Janos L. 
Published: July 2008

Abstract
This paper examines the role of mechanical stratigraphy on the evolution of normal fault geometry and fault zone internal structure, using a well-exposed normal fault system from the Permian Lodève Basin, southern France. Faults formed early during the syn-deformation tilting history of the basin tend to have steeper segments in the competent sandstone layers due to refraction, assisted by pre-existing early bedding-perpendicular joints, where displacement remained on the order of bed thickness. Faults which continued to slip during tilting have a more complex structure of splays due both to the space incompatability problem of slip at fault bends of this irregular geometry, and because tilting favours the generation of new splays at a different angle to the earlier faults experiencing rotation. Continued deformation between faults and their splays often causes both distributed deformation in between the two, and reconnection of splays to the main fault forming isolated lenses. Thus, fault zone complexity increases greatly as slip exceeds competent bed thickness, owing both to the presence of the mechanical layering, and the fact that this layering is being tilted.
Displacement-length scaling for single-event fault ruptures: insights from Newberry Springs Fault Zone and implications for fault zone structure
Authors: Ferrill David A. , Smart Kevin J. , Necsoiu Marius 
Published: July 2008

Abstract

The Newberry Springs Fault Zone experienced slip associated with the 1992 Landers earthquake in the Mojave Desert of California, USA. Detailed analysis of scaling relationships from single-event ground ruptures in the Newberry Springs Fault Zone mapped in the field shows an average maximum displacement to length (
D
max
/
L
) relationship for fault segments (rupture lengths in the range of 100–1000 m) of 8×10
−5
–consistent with previously published
D
max
/
L
ratios for normal fault earthquake ground ruptures (rupture lengths in the range of 1–100 km) of 7×10
−5
. To explore the ability of remote sensing (interferometric synthetic aperture radar or InSAR) to map small-displacement single-event fault ruptures and add constraints on segment displacements, we applied established interferometry methods with phase unwrapping to produce maps of line-of-sight displacement and displacement gradient. These maps highlight fault traces that experienced displacement during the time between collection of the synthetic aperture radar images. Comparison of published 1992 single-event ground rupture maps with mapping based on photogeologic interpretation of 1950s vintage aerial photographs indicates that most of the 1992 ruptures occurred as reactivation of pre-existing slip surfaces. In general,
D
max
/
L
for total fault displacement is approximately 100 times
D
max
/
L
for single-event ruptures. Evidence from the Newberry Springs Fault Zone indicates that, since the Pleistocene, at least 10–20 Landers-like slip events have occurred, reactivating the Newberry Springs Fault Zone. Evidence of wide damage zones and reactivation of individual segments developed in alluvial floodplain deposits, at relatively small (order of metres) fault displacements, supports a conceptual model of fault damage zone width being established early, during fault propagation. With continued displacement by accumulation of additional slip events, fault zone damage intensifies. The fault zone width may remain relatively stable, although the active portion of the fault zone will likely narrow as faulting continues and a throughgoing slip surface develops and accumulates the bulk of displacement.
Normal fault terminations in limestones from the SE-Basin (France): implications for fluid flow
Authors: Micarelli L. , Benedicto A. 
Published: July 2008

Abstract
The geometry and evolution of normal fault terminations were studied in Tithonian limestones exposed on a vertical cliff in the French SE-Basin. The rocks consist of mainly limestone layers alternated with thin clayey interlayers. All studied fault zones die out vertically into bed-perpendicular veins striking approximately parallel to the fault. Displacement decreasing to zero towards the fault tip is accommodated horizontally by bed-parallel opening of calcite veins, and vertically by bed-perpendicular localized compaction. The latter mechanism leads the clayey interlayers to be thinned and in places completely pushed out, and enhances pressure solution in bed-parallel seams. The respective thicknesses of the limestone layers and clayey interlayers, and the ratio between local displacement amount and bed thickness influence the geometries of the fault termination and of the steps between slip surfaces. Relatively thick clayey interlayers localize low-angle slip surfaces and may impede the vertical propagation of the slip surface. Vertical fault restriction is also related to thick limestone layers, which are deflected and affected by outer arc extensional fractures, localized pressure solution and dilational jogs connecting adjacent propagating slip surfaces. However, beds keep their continuity if thicker than the local displacement amount. Where the local displacement is larger than the layer thickness, limestone beds are disconnected and clayey interlayers are completely cut but the slip surfaces. Tip-point veins, as well as outer arc veins, do not cross the clayey interlayers and fluid flow is local and confined within one limestone layer. In contrast, dilational jogs in places cut through several layers, and the breaking of clayey interlayers causes an increase in fluid flow. Conduits can be opened along the fault zone and fluids are driven into the jog, so slip surfaces may communicate separate reservoirs, until dilational jogs are sealed by mineral precipitation.
On the structure and mechanical properties of large strike-slip faults
Authors: Faulkner D. R. , Mitchell T. M. , Rutter E. H. , Cembrano J. 
Published: July 2008

Abstract

Elucidation of the internal structure of fault zones is paramount for understanding their mechanical, seismological and hydraulic properties. In order to observe representative brittle fault zone structures, it is preferable that the fault be passively exhumed from seismogenic depths and the exposure must be in arid or semi-arid environments where the fragile rocks are not subject to extensive weathering. Field observations of two such faults are used to constrain their likely mechanical properties. One fault is the Carboneras fault in southeastern Spain, where the predominant country rocks are phyllosilicate-rich lithologies, and the other is part of the Atacama fault system in northern Chile, where faults pass through crystalline rocks of acidic to intermediate composition. The Carboneras fault is a left lateral fault with several tens of kilometres offset exhumed from approximately 4 km depth, and displays multiple strands of clay-bearing fault gouge, each several metres wide, that contain variably fractured lenses of protolithic mica schists. The strain is evenly distributed across the gouge layers, in accordance with the measured laboratory mechanical behaviour which shows predominantly strain hardening characteristics. The overall width of the fault zone is several hundred metres. Additionally, there are blocks of dolomitic material that are contained within the fault zones that show extremely localized deformation in the form of faults several centimetres wide. These are typically arranged at an angle of
c
. 20° to the overall fault plane. These differing types of fault rock products allow for the possibility of ‘mixed mode’ seismicity, with fault creep occurring along the strands of velocity strengthening clay-rich gouge, punctuated by small seismic events that nucleate on the velocity weakening localized faults within the dolomite blocks. The Caleta Coloso fault in northern Chile has a left-lateral offset of at least 5 km and was exhumed from 5–10 km depth. The fault core is represented by a 200–300 m wide zone of hydrothermally altered protocataclasite and ultracataclasite. This is surrounded by a zone of micro and macro-fractures on the order of 150 m thick. The fault core shows a heterogeneous distribution of strain, with alternate layers of ultracataclasite and lower strain material. The strain-weakening behaviour of crystalline rocks might be expected to produce highly localized zones of deformation, and thus the wide core zone must be a result of additional process such as precipitation strengthening or geometric irregularities along the fault plane.