bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of the structural controls on oil recovery from shallow-marine reservoirs
Authors: Manzocchi T. , Matthews J. D. , Strand J. A. , Carter J. N. , Skorstad A. , Howell J. A. , Stephen K. D. , Walsh J. J.
Published: October 2008

The differences in oil production are examined for a simulated waterflood of faulted and unfaulted versions of synthetic shallow-marine reservoir models with a range of structural and sedimentological characteristics. Fault juxtaposition can reduce the economic value of the reservoirs by up to 30%, with the greatest losses observed in models with lower sedimentological aggradation angles and faults striking parallel to waterflood direction. Fault rock has a greater effect than fault juxtaposition on lowering the economic value of the reservoir models in the compartmentalized cases only – and only when the fault rock permeability model is based on the least permeable published laboratory data. Moderately sealing faults can increase the economic value of reservoirs except when the main flow direction is parallel to the faults. These results arise from the dependence of economic value on both sweep efficiency and production rate. Simple predictors of fault juxtaposition and fault-rock heterogeneity have been established and combined with two-dimensional considerations from streamline theory in an attempt to capture quantitatively the change in economic reservoir value arising from faults. Despite limitations associated with the three-dimensional role of juxtaposition, the results are encouraging and represent a step towards establishing a rapid transportable predictor of the effects of faults on production.
Sedimentological parameterization of shallow-marine reservoirs
Authors: Howell John A. , Skorstad Arne , MacDonald Alister , Fordham Alex , Flint Stephen , Fjellvoll Bjørn , Manzocchi Tom
Published: October 2008

The key causes of heterogeneity within progradational shallow-marine reservoirs have been defined as: shoreline type (wave vs. fluvial dominated); shoreline trajectory; the presence of permeability contrasts associated with dipping clinoform surfaces within the shoreface or delta front; the presence of cemented barriers between parasequences; and the progradation direction of the shoreline (described with respect to the main waterflood direction in the simulated reservoir). These parameters were recorded from a series of 56 modern and ancient depositional systems from a variety of climatic and tectonic settings. These data were then used to build the 408 synthetic sedimentological models that formed the basis for the SAIGUP study.
Optimization of a reservoir development plan using a parallel genetic algorithm
Authors: Carter Jonathan N. , Matthews John D.
Published: October 2008

A parallel genetic algorithm has been applied successfully to design a production plan that is substantially superior to that obtained using a conventional engineering approach. The reservoir, a dipping structure, was expected to yield optimum production using a rolling line drive from downdip to updip positions. The simulation allowed for 3800 positions for each of 11 wells, giving a total of 1.3×10
31
options. The genetic algorithm sampled 1650 of these and was able to identify seven solutions that would increase production by over 30% compared with the rolling line drive. In contrast, a random search using 850 samples managed to find only two plans that improved production; in each of these cases the improvement was less than 1%.
Sensitivity of the impact of geological uncertainty on production from faulted and unfaulted shallow-marine oil reservoirs: objectives and methods
Authors: Manzocchi T. , Carter J. N. , Skorstad A. , Fjellvoll B. , Stephen K. D. , Howell J. A. , Matthews J. D. , Walsh J. J. , Nepveu M. , Bos C. , Cole J. , Egberts P. , Flint S. , Hern C. , Holden L. , Hovland H. , Jackson H. , Kolbjørnsen O. , MacDonald A. , Nell P. A. R. , Onyeagoro K. , Strand J. , Syversveen A. R. , Tchistiakov A. , Yang C. , Yielding G. , Zimmerman R. W.
Published: October 2008

Estimates of recovery from oil fields are often found to be significantly in error, and the multidisciplinary SAIGUP modelling project has focused on the problem by assessing the influence of geological factors on production in a large suite of synthetic shallow-marine reservoir models. Over 400 progradational shallow-marine reservoirs, ranging from comparatively simple, parallel, wave-dominated shorelines through to laterally heterogeneous, lobate, river-dominated systems with abundant low-angle clinoforms, were generated as a function of sedimentological input conditioned to natural data. These sedimentological models were combined with structural models sharing a common overall form but consisting of three different fault systems with variable fault density and fault permeability characteristics and a common unfaulted end-member. Different sets of relative permeability functions applied on a facies-by-facies basis were calculated as a function of different lamina-scale properties and upscaling algorithms to establish the uncertainty in production introduced through the upscaling process. Different fault-related upscaling assumptions were also included in some models. A waterflood production mechanism was simulated using up to five different sets of well locations, resulting in simulated production behaviour for over 35 000 full-field reservoir models. The model reservoirs are typical of many North Sea examples, with total production ranging from
c
. 15×10
6
 m
3
to 35×10
6
 m
3
, and recovery factors of between 30% and 55%. A variety of analytical methods were applied. Formal statistical methods quantified the relative influences of individual input parameters and parameter combinations on production measures. Various measures of reservoir heterogeneity were tested for their ability to discriminate reservoir performance. This paper gives a summary of the modelling and analyses described in more detail in the remainder of this thematic set of papers.
Characterization of turbidites from the Urucutuca Formation of the Almada Basin, Bahia, Brazil, using seismic and petrophysical well log data
Authors: Lima Klédson Tomaso P. , Dias Carlos Alberto
Published: October 2008

Fifty seismic lines and petrophysical logs from 15 wells were used to characterize the reservoirs of the Urucutuca Formation palaeo-canyon in the Almada Basin. The resulting 3D geological model allowed the Urucutuca Formation and its turbidite canyons to be evaluated as potential petroleum reservoirs. The log analyses indicate great variations in effective porosity (reaching a maximum value of 25%) and the clay content of the sandstones (ranging from less than 5% to greater than 40%). Other relevant factors in this context are the sandstone and calcarenite thicknesses which reach 243 m and 93 m, respectively. Information obtained from the seismic lines indicates that there was a strong tectonic influence on the geometry of the Almada Canyon, resulting in the formation of two canyons that join in the offshore portion of the basin. The connection between the canyons has been observed to extend from the continent to 27 km offshore. The results indicate that the Urucutuca Formation is an important horizon for future oil exploration, having favourable genetic and petrophysical characteristics.
Pressure regression, fluid drainage and a hydrodynamically controlled fluid contact in the North Sea, Lower Cretaceous, Britannia Sandstone Formation
Authors: O'Connor Stephen A. , Swarbrick Richard E.
Published: October 2008

The Lower Cretaceous Britannia Sandstone Formation is located below overpressured Sola Formation shales (
c
. 2800 psi overpressure) and above Jurassic reservoirs (up to 5700 psi overpressure) and represents a pressure regression, recording overpressure values ranging from approximately 100 psi in Block 15/30 (in the extensional Outer Moray Firth/Central North Sea basin) up to a maximum of approximately 1600 psi in Block 22/4. The Britannia Sandstone has an anomalously low overpressure when compared with deeper Cretaceous (Valhall) and Jurassic reservoir overpressures locally, and further afield in the Central North Sea at similar depths.

The pore pressures in the Sola Formation shales have been estimated using conventional porosity/sonic-based prediction methods, indicating strong overpressure disequilibrium between the Sola Formation shales and the Britannia Sandstones, both in the Britannia Field area and in the laterally age-equivalent sands to the west referred to as the Kopervik Fairway (the Aptian sands of the South Halibut Basin, forming the reservoirs of the Blake, Captain and Goldeneye fields).

Burial curve modelling indicates that it is likely that the Sola Formation shales have overpressured for the last 4 Ma, and likely much longer, suggesting an early history of pressure build up (now preserved in the Sola Formation shales and deeper, Jurassic reservoirs and associated sediments). The adjacent Britannia Sandstone Formation therefore lost fluid and pressure due to local availability of a fluid conduit. Resulting active fluid flow, driven by overpressure differences in the Britannia Sandstone Formation, has created a hydrodynamically tilted hydrocarbon–water contact with lateral flow from east to west. Well evidence indicates vertical flow from shallower reservoirs into the stratigraphically deeper, main Britannia reservoir. The fluid escape could be either laterally via the Kopervik Fairway and/or vertically through the Upper Cretaceous Chalk facilitated by fractures/faulting.
Enhanced depositional and AVO models for lithologically complex sandstones in the Santos Basin, offshore Brazil
Authors: Klarner Sabine , Ujetz Bernhardt , Fontana Rogério L.
Published: October 2008

While exploring for hydrocarbons in rift-related basins, volcanic and volcaniclastic rocks and their erosional products are commonly encountered lithologies. At the reservoir level, the presence of rock types derived from volcanism or affected by post-volcanic re-deposition leads to highly varied complex lithologies with wide ranges of inherent rock properties.

In the Santos Basin, a number of exploration wells have encountered basalts emplaced along the basin hinge line that have controlled the sedimentation and basin geometry. The main reservoir units of the basin consist of complex Upper Cretaceous sandstones deposited during periods of active volcanism. For one of the main exploration targets, the Senonian Ilhabela Formation, integrated geological and geophysical interpretation of recently acquired seismic and well data has led to a refined sedimentological model, an enhanced AVO model as well as a deeper understanding of the petroleum system. The encountered sandstones are of shallow-marine and deltaic origin, with local occurrence of mafic volcanic and subvolcanic rocks. Dependent on the presence of volcanic rocks in the vicinity of the particular reservoir, two different types of sandstones with different AVO characteristics have been identified. The presence of volcanic rocks may be interpreted from seismic data by their distinct geometry, usually high amplitudes and unique AVO behaviour, expressed as a strengthening of positive amplitudes with increasing offset.
Stratigraphic modelling of turbidite prospects to reduce exploration risk
Authors: Waltham Dave , Jaffey Noah , MacLean Stuart , Zampetti Valentina
Published: October 2008

This article presents an integrated workflow to model the evolution of ancient turbidity currents on a 3D structurally reconstructed palaeo-seafloor, allowing ancient turbidite sediment distributions to be estimated. Effective use of such approaches requires efficient model-inversion procedures so that model parameters (e.g. flow dimensions, densities etc.) can be estimated from any available data. It is shown that a directed Monte Carlo approach (i.e. a simple genetic search algorithm) is very effective. A case study of a Mesozoic prospect in the UK North Sea shows the power of these methods to discriminate between potentially attractive sediment-source locations. The main power of this approach lies in its ability to exclude many, otherwise attractive, sedimentation scenarios.
Analysing exploration uncertainties by tight integration of seismic and hydrocarbon migration modelling
Authors: Sylta Øyvind
Published: October 2008

High success rates in the exploration for oil and gas can be achieved by incorporating best practice strategies in estimating the geological uncertainties from seismic data and geological models. A tight coupling of the seismic information and hydrocarbon migration modelling may allow for a consistent handling of uncertainties throughout the analysis. Seismic uncertainties include velocities used for depth conversion, the positioning of structural interpretations including faults, and assigning flow properties from seismic attributes. The necessary output from the seismic uncertainty analysis could be provided as uncertainty fields that may be used as input to hydrocarbon migration modelling.

The nonlinearity of the hydrocarbon migration process, including flow-path selection and trap phase filtering, frequently requires that local uncertainties are addressed in more detail. These uncertainties may require high-resolution seismic analyses in order to be further resolved. The structural interpretation is of particular importance to accumulation uncertainties, and fault juxtaposition and carrier dip direction uncertainty estimations can improve phase prediction estimates in exploration prospects. It is suggested that an improved best practice for exploration for oil and gas should include a tight coupling of the handling of uncertainties from seismic data in hydrocarbon migration modelling.
A survey of top-
k
query processing techniques in relational database systems
Authors: Ilyas Ihab F. , Beskales George , Soliman Mohamed A.
Published: October 2008

Efficient processing of top-
k
queries is a crucial requirement in many interactive environments that involve massive amounts of data. In particular, efficient top-
k
processing in domains such as the Web, multimedia search, and distributed systems has shown a great impact on performance. In this survey, we describe and classify top-
k
processing techniques in relational databases. We discuss different design dimensions in the current techniques including query models, data access methods, implementation levels, data and query certainty, and supported scoring functions. We show the implications of each dimension on the design of the underlying techniques. We also discuss top-
k
queries in XML domain, and show their connections to relational approaches.
A New q‐Analogue of Bernoulli Polynomials Associated with p‐Adic q‐Integrals
Authors: Jang Lee-Chae
Published: October 2008

We will study a new q‐analogue of Bernoulli polynomials associated with p‐adic q‐integrals. Furthermore, we examine the Hurwitz‐type q‐zeta functions, replacing p‐adic rational integers x with a q‐analogue [x] q for a p‐adic number q with |q−1|p < 1, which interpolate q‐analogue of Bernoulli polynomials.
Child-Centered Evaluation: Broadening the Child/Designer Dyad
Authors: Pardo Sofia , Howard Steve , Vetere Frank
Published: October 2008

Some settings challenge a literal interpretation of user-centered design orthodoxy; that design is best donefora user, by designingwiththat user. We explore the value that a copresent proxy and interpreter can bring to certainhard-to-reachordifficult-to-interpretsituations; in this case the evaluation of educational software intendedto be usedby children. We discuss the effect that introducing a teacher had on the results of the evaluation and conclude that adding an expert-based component to evaluations increased its diagnostic power.
A Tunable Energy Filter for Medical X‐Ray Imaging
Authors: Fredenberg Erik , Cederström Björn , Åslund Magnus , Ribbing Carolina , Danielsson Mats
Published: October 2008

A multiprism lens (MPL) is a refractive X‐ray lens, and its chromatic properties can be employed in an energy filtering setup to obtain a narrow tunable X‐ray spectrum. We present the first evaluation of such a filter for medical X‐ray imaging. The experimental setup yields a 6.6 gain of flux at 20 keV, and we demonstrate tunability by altering the energy spectrum to center also around 17 and 23 keV. All measurements are found to agree well with ray‐tracing and a proposed geometrical model. Compared to a model mammography system with absorption filtering, the experimental MPL filter reduces dose 13–25% for 3–7 cm breasts if the spectrum is centered around the optimal energy. Additionally, the resolution is improved 2.5 times for a 5 cm breast. The scan time is increased 3 times but can be reduced with a slightly decreased energy filtering and resolution.
Evaluation of Bcl‐2 Expression and Caspase‐3 in STZ‐Induced Diabetic Rats
Authors: Jafari Anarkooli Iraj , Sankian Mojtaba , Ahmadpour Shahriar , Varasteh Abdol-ReZa , Haghir Hossein
Published: October 2008

We assessed the expression of Bcl‐2 family members at both mRNA and protein levels as well as the Caspase‐3 activity, in order to investigate the occurrence of apoptosis in hippocampus of STZ‐induced diabetic rats. We selected twenty‐four Wistar rats; half of them were made diabetic by intraperitoneal injection of a single 60 mg/kg dose of streptozotocin (STZ, IP), while the others received normal saline and served as controls. The expressions of Bcl‐2, Bcl‐xL, and Bax mRNA and proteins were measured using RT‐PCR and western blotting, respectively. Caspases‐3 activity was determined by using the Caspase‐3/CPP32 Fluorometric Assay Kit. The result showed that mRNA
and protein levels of Bcl‐2 and Bcl‐xL were lower in hippocampus of diabetic group than that of the control group, whereas expressions of Bax in hippocampus of diabetic rats were higher than that of controls at both mRNA
and protein levels (P < .01). Hyperglycemia was found to raise 6.9‐fold hippocampal caspase‐3 activity in diabetic group compared with control group (P < .001). Therefore, the induction of diabetes is associated with increased ratios of Bax/Bcl‐2, Bax/Bcl‐xL, and increased caspase‐3 activity in hippocampus which shows that apoptosis is favored in hippocampal region.
A Simple Mechanism for Throttling High‐Bandwidth Flows
Authors: Chang Chia-Wei , Lin Bill
Published: October 2008

This letter presents BREATHe, a simple packet dropping
scheme for identifying and throttling unresponsive or misbehaving
high‐bandwidth flows during times of congestion. BREATHe
is different from the existing active queue management techniques
in that it uses heavy‐hitter set analysis to identify highbandwidth
flows rather than sampling or rate estimation. Specifically,
BREATHe uses heavy‐hitter set analysis to detect highbandwidth
flows that exceed some target rate rlimit and preferentially
drop packets from these flows. We show that the proposed
mechanism is effective at throttling high‐bandwidth flows using
a small amount of state and low‐complexity operation.
Molecular and Biochemical Effects of a Kola Nut Extract on Androgen Receptor-Mediated Pathways
Authors: Solipuram Rajasree , Koppula Sowmya , Hurst Angela , Harris Kinesha , Naragoni Srivatcha , Fontenot Krystal , Gray Wesley
Published: October 2008

The low incidence of prostate cancer in Asians has been attributed to chemopreventative properties of certain chemicals found in their diet. This study characterized the androgenic and chemopreventative properties of the Jamaican bush tea “Bizzy,” using androgen receptor positive and negative cell lines. Exposure of prostate cells to Biz-2 resulted in a growth inhibition (GI50) of 15 ppm in LNCaP cells and 3.6 ppm in DU145 cells. Biz-2 elicited a 2-fold increase in the mRNA of the anti-apoptotic gene Bcl2, with a 10-fold increase in that of the proapoptotic gene Bax. We observed a 2.4- to 7.5-fold change in apoptotic cells in both cell lines. Biz-2 at 10 ppm elicited a time- and dose-dependent stimulation of both the protein and mRNA levels of several androgen-regulated genes. Biz-2 caused a 36% decrease in PSA secretion and a significant increase in PSA mRNA. The relative binding affinity (IC50) of Biz-2 for AR was 2- to 5-fold lower than that of the synthetic androgen R1881. Biz-2 was found to be a specific ligand for the AR in that the natural ligand, DHT, and the anti-androgen, flutamide, displaced Biz-2 bound to AR and inhibited Biz-2-induced transcription and PSA secretion. This study provided evidence that Biz-2 extract possesses the ability to modulate prostate cancer cell biology in an AR-dependent manner.
Cardiovascular Stress Hyperreactivity in Babies of Smokers and in Babies Born Preterm
Authors: Cohen Gary , Vella Silvano , Jeffery Heather , Lagercrantz Hugo , Katz-Salamon Miriam
Published: October 2008

Background—

Being born preterm, small, and to a mother who smokes are common perinatal complications with major public health implications. Evidence suggests that each affects the body’s structure and function in ways that could increase susceptibility to cardiovascular dysfunction later in life. Here, we used 2 routine stress reactivity tests to identify incipient “silent” programming of cardiovascular dysfunction associated with adverse perinatal events.

Methods and Results—

We studied 29 control babies born at term to nonsmokers, 18 term-born babies of mothers who smoked throughout pregnancy (mean, 15 cigarettes a day), and 31 babies born preterm to nonsmokers. All infants were compared at the same age after conception (ie, at 40 to 42 weeks), during sleep. We analyzed blood pressure (BP) and heart rate responses to breathing 4% CO
2
for 4 minutes or to passive head-up tilt to 60°. BP was measured continuously from a wrist cuff. CO
2
exposure raised heart rate and BP in controls by 10%, and tilt increased their BP by 5%. CO
2
elicited the expected BP but no heart rate response from preterm infants but a much-greater-than-expected BP and heart rate response from babies of smokers. Tilt elicited a 3- to 4-fold greater rise in BP from preterm and tobacco-exposed babies.

Conclusions—

Vascular, cardiac, and blood pressure reactivity is heightened in babies born preterm or to smokers. The findings are consistent with in utero and early postnatal “programming” of human cardiovascular dysfunction by adverse circumstances. This incipient dysfunction may be an early manifestation of processes that lead to other problems or complications later on (eg, higher BP or sudden infant death syndrome).
Real-Time Catheter Molecular Sensing of Inflammation in Proteolytically Active Atherosclerosis
Authors: Jaffer Farouc A. , Vinegoni Claudio , John Michael C. , Aikawa Elena , Gold Herman K. , Finn Aloke V. , Ntziachristos Vasilis , Libby Peter , Weissleder Ralph
Published: October 2008

Background—

To enable intravascular detection of inflammation in atherosclerosis, we developed a near-infrared fluorescence (NIRF) catheter-based strategy to sense cysteine protease activity during vascular catheterization.

Methods and Results—

The NIRF catheter design was based on a clinical coronary artery guidewire. In phantom studies of NIRF plaques, blood produced only a mild (<30%) attenuation of the fluorescence signal compared with saline, affirming the favorable optical properties of the NIR window. Catheter evaluation in vivo used atherosclerotic rabbits (n=11). Rabbits received an injection of a cysteine protease-activatable NIRF imaging agent (Prosense750; excitation/emission, 750/770 nm) or saline. Catheter pullbacks through the blood-filled iliac artery detected NIRF signals 24 hours after injection of the probe. In the protease agent group, the in vivo peak plaque target-to-background ratio was 558% greater than controls (6.8±1.9 versus 1.3±0.3, mean±SEM;
P
<0.05). Ex vivo fluorescence reflectance imaging corroborated these results (target-to-background ratio, 10.3±1.8 for agent versus 1.8±0.3 for saline group;
P
<0.01). In the protease group only, saline flush-modulated NIRF signal profiles further distinguished atheromata from normal segments in vivo (
P
<0.01). Good correlation between the in vivo and ex vivo plaque target-to-background ratio was present (
r
=0.82,
P
<0.01). Histopathological analyses demonstrated strong NIRF signal in plaques only from the protease agent group. NIRF signals colocalized with immunoreactive macrophages and the cysteine protease cathepsin B.

Conclusions—

An intravascular fluorescence catheter can detect cysteine protease activity in vessels the size of human coronary arteries in real time with an activatable NIRF agent. This strategy could aid in the detection of inflammation and high-risk plaques in small arteries.
Increased Inflammatory Gene Expression in ABC Transporter–Deficient Macrophages
Authors: Yvan-Charvet Laurent , Welch Carrie , Pagler Tamara A. , Ranalletta Mollie , Lamkanfi Mohamed , Han Seongah , Ishibashi Minako , Li Rong , Wang Nan , Tall Alan R.
Published: October 2008

Background—

Two macrophage ABC transporters, ABCA1 and ABCG1, have a major role in promoting cholesterol efflux from macrophages. Peritoneal macrophages deficient in ABCA1, ABCG1, or both show enhanced expression of inflammatory and chemokine genes. This study was undertaken to elucidate the mechanisms and consequences of enhanced inflammatory gene expression in ABC transporter–deficient macrophages.

Methods and Results—

Basal and lipopolysaccharide-stimulated thioglycollate-elicited peritoneal macrophages showed increased inflammatory gene expression in the order
Abca1
−/−
Abcg1
−/−
>
Abcg1
−/−
>
Abca1
−/−
>wild-type. The increased inflammatory gene expression was abolished in macrophages deficient in Toll-like receptor 4 (TLR4) or MyD88/TRIF. TLR4 cell surface concentration was increased in
Abca1
−/−
Abcg1
−/−
>
Abcg1
−/−
>
Abca1
−/−
> wild-type macrophages. Treatment of transporter-deficient cells with cyclodextrin reduced and cholesterol-cyclodextrin loading increased inflammatory gene expression.
Abca1
−/−
Abcg1
−
bone marrow–derived macrophages showed enhanced inflammatory gene responses to TLR2, TLR3, and TLR4 ligands. To assess in vivo relevance, we injected intraperitoneally thioglycollate in
Abcg1
−/−
bone marrow–transplanted, Western diet–fed,
Ldlr
-deficient mice. This resulted in a profound inflammatory infiltrate in the adventitia and necrotic core region of atherosclerotic lesions, consisting primarily of neutrophils.

Conclusions—

The results suggest that high-density lipoprotein and apolipoprotein A-1 exert anti-inflammatory effects by promoting cholesterol efflux via ABCG1 and ABCA1 with consequent attenuation of signaling via Toll-like receptors. In response to a peripheral inflammatory stimulus, atherosclerotic lesions containing
Abcg1
−/−
macrophages experience an inflammatory “echo,” suggesting a possible mechanism of plaque destabilization in subjects with low high-density lipoprotein levels.
Impact of Statin Use on Outcomes After Coronary Artery Bypass Graft Surgery
Authors: Kulik Alexander , Brookhart M. Alan , Levin Raisa , Ruel Marc , Solomon Daniel H. , Choudhry Niteesh K.
Published: October 2008

Background—

The benefits of statins have been demonstrated for patients with a remote history of coronary artery bypass grafting (CABG); however, no investigation to date has evaluated whether initiation of statin therapy in the early months after surgery improves clinical outcomes.

Methods and Results—

A retrospective cohort of 7503 Medicare patients ≥65 years of age who underwent CABG (1995–2003) was assembled by use of linked hospital and pharmacy claims data. Rates of all-cause mortality and major adverse cardiovascular events were compared between patients who were (n=1745) and were not (n=5788) prescribed statins within 1 month of CABG discharge. Additional analyses evaluated the impact of statin initiation between 1 and 6 months after surgery. Multivariable and propensity score analysis demonstrated that statin use within 1 month of CABG discharge independently reduced the risk of all-cause mortality (adjusted hazard ratio 0.82, 95% confidence interval 0.72 to 0.94) compared with no statin use. Similarly, statin use within 1 month of CABG discharge independently reduced the risk of major adverse cardiovascular events (adjusted hazard ratio 0.89, 95% confidence interval 0.81 to 0.98). Initiation of statin therapy between 1 and 6 months after CABG discharge was also associated with reductions in major adverse cardiovascular events and mortality; however, outcome rates between early (≤1 month after CABG) and delayed (1 to 6 months after CABG) statin initiation were not significantly different.

Conclusions—

Statin therapy initiated in the early months after hospital discharge independently reduces all-cause mortality and major adverse cardiovascular events after CABG. These findings validate the widespread practice of prescribing long-term statin therapy after CABG.
Reduced Selenium Concentrations and Glutathione Peroxidase Activity in Preeclamptic Pregnancies
Authors: Mistry Hiten D. , Wilson Vicky , Ramsay Margaret M. , Symonds Michael E. , Pipkin Fiona Broughton
Published: October 2008

Preeclampsia is pregnancy-specific, affecting 2% to 7% of women, and is a leading cause of perinatal and maternal morbidity and mortality. Preeclampsia may also predispose the fetus to increased risks of adult cardiovascular disease. Selenium, acting through the selenoprotein glutathione peroxidases, has critical roles in regulating antioxidant status. Recent reports implicate poor maternal selenium status as a nutritional factor predisposing the mother to preeclampsia but the fetus and placenta have not been studied in tandem. Measurement of selenium concentrations, expression, and activity levels of glutathione peroxidase and markers of oxidative stress were performed on maternal and umbilical venous blood samples or the placenta from 27 normal pregnant, 25 preeclamptic, and 22 healthy age-matched nonpregnant women. The results of this study revealed highly significant reductions in serum selenium concentrations and plasma glutathione peroxidase activity in pregnancy per se compared to nonpregnant controls. Moreover, these levels were further decreased in the preeclamptic mothers and babies compared to normal pregnancies. Umbilical venous selenium was particularly low (42.1±11.8 and 29.0±9.9 μg/L; mean±SD;
P
<0.05). Both mother and baby had significantly increased levels of markers for oxidative stress in the preeclamptic group. The placental glutathione peroxidase activity and immunohistochemical staining were also reduced in the preeclampsia placentae. Oxidative stress associated with preeclampsia may be a consequence of reduced antioxidant defense pathways specifically involving glutathione peroxidases, perhaps linked to reduced selenium availability. Reduced glutathione peroxidases could be associated with increased generation of toxic lipid peroxides contributing to the endothelial dysfunction and hypertension of preeclampsia.
Neonatal Oxygen Exposure in Rats Leads to Cardiovascular and Renal Alterations in Adulthood
Authors: Yzydorczyk Catherine , Comte Blandine , Cambonie Gilles , Lavoie Jean-Claude , Germain Nathalie , Ting Shun Yue , Wolff Julie , Deschepper Christian , Touyz Rhian M. , Lelièvre-Pegorier Martine , Nuyt Anne Monique
Published: October 2008

Long-term vascular and renal consequences of neonatal oxidative injury are unknown. Using a rat model, we sought to investigate whether vascular function and blood pressure are altered in adult rats exposed to hyperoxic conditions as neonates. We also questioned whether neonatal O
2
injury causes long-term renal damage, important in the pathogenesis of hypertension. Sprague-Dawley pups were kept with their mother in 80% O
2
or room air from days 3 to 10 postnatal, and blood pressure was measured (tail cuff) from weeks 7 to 15. Rats were euthanized, and vascular reactivity (ex vivo carotid rings), oxidative stress (lucigenin chemiluminescence and dihydroethidium fluorescence), microvascular density (tibialis anterior muscle), and nephron count were studied. In male and female rats exposed to O
2
as newborns, systolic and diastolic blood pressures were increased (by an average of 15 mm Hg); ex vivo, maximal vasoconstriction (both genders) and sensitivity (males only) specific to angiotensin II were increased; endothelium-dependant vasodilatation to carbachol but not to NO-donor sodium nitroprussiate was impaired; superoxide dismutase analogue prevented vascular dysfunction to angiotensin II and carbachol; vascular superoxide production was higher; and capillary density (by 30%) and number of nephrons per kidney (by 25%) were decreased. These data suggest that neonatal hyperoxia leads in the adult rat to increased blood pressure, vascular dysfunction, microvascular rarefaction, and reduced nephron number in both genders. Our findings support the hypothesis of developmental programming of adult cardiovascular and renal diseases and provide new insights into the potential role of oxidative stress in this process.
Autoantibodies to the Angiotensin Type I Receptor in Response to Placental Ischemia and Tumor Necrosis Factor α in Pregnant Rats
Authors: LaMarca Babbette , Wallukat Gerd , Llinas Mayte , Herse Florian , Dechend Ralf , Granger Joey P.
Published: October 2008

Circulating factors, such as agonistic autoantibodies to the angiotensin II type 1 (AT1) receptor (AT1-AAs), and inflammatory cytokines, including tumor necrosis factor α (TNF-α), are suggested to be important links between placental ischemia and hypertension in preeclamptic women. The purpose of this study was to determine the role of placental ischemia and TNF-α in stimulating the AT1-AA and the importance of AT1 receptor activation in mediating hypertension during reductions in uterine perfusion pressure (RUPP) and chronic TNF-α excess in pregnant rats. Increased mean arterial pressure in RUPP pregnant rats (122±1 mm Hg RUPP versus 101±1 mm Hg normal pregnant [NP];
P
<0.001) was associated with increased circulating TNF-α (RUPP 48±13 pg/mL versus N 8±1 pg/mL;
P
<0.05) and AT1-AA (RUPP 15.3±1.6 U versus NP 0.6±0.3 U;
P
<0.001). Moreover, TNF-α–induced hypertension (97±2 to 112±2 mm Hg;
P
<0.05) in pregnant rats was associated with AT1-AA production (TNF-α rats 9.2±2.3 U versus NP rats 1.0±0.8 U;
P
<0.05). To determine the importance of AT1 receptor activation in mediating hypertension in RUPP– and TNF-α–treated rats, we administered an AT1 receptor antagonist to RUPP–, TNF-α–treated, and NP rats. Blood pressure responses were attenuated in RUPP rats (Δ 32 mm Hg versus Δ 20 mm Hg, NP;
P
<0.001), as well as in TNF-α–treated rats (Δ 10 mm Hg versus Δ 5 mm Hg, NP;
P
<0.05). Collectively, these data indicate that placental ischemia and TNF-α are important stimuli of AT1-AA, and activation of the AT1 receptor appears to, in part, mediate hypertension produced by RUPP and TNF-α in pregnant rats.
An Effective Hierarchical Model for the Biomolecular Covalent Bond: An Approach Integrating Artificial Chemistry and an Actual Terrestrial Life System
Authors: Oohashi Tsutomu , Ueno Osamu , Maekawa Tadao , Kawai Norie , Nishina Emi , Honda Manabu
Published: October 2008

Under the AChem paradigm and the programmed self-decomposition (PSD) model, we propose a hierarchical model for the biomolecular covalent bond (HBCB model). This model assumes that terrestrial organisms arrange their biomolecules in a hierarchical structure according to the energy strength of their covalent bonds. It also assumes that they have evolutionarily selected the PSD mechanism of turning biological polymers (BPs) into biological monomers (BMs) as an efficient biomolecular recycling strategy. We have examined the validity and effectiveness of the HBCB model by coordinating two complementary approaches: biological experiments using existent terrestrial life, and simulation experiments using an AChem system. Biological experiments have shown that terrestrial life possesses a PSD mechanism as an endergonic, genetically regulated process and that hydrolysis, which decomposes a BP into BMs, is one of the main processes of such a mechanism. In simulation experiments, we compared different virtual self-decomposition processes. The virtual species in which the self-decomposition process mainly involved covalent bond cleavage from a BP to BMs showed evolutionary superiority over other species in which the self-decomposition process involved cleavage from BP to classes lower than BM. These converging findings strongly support the existence of PSD and the validity and effectiveness of the HBCB model.
A Synthon Approach to Artificial Chemistry
Authors: Lenaerts Tom , Bersini Hugues
Published: October 2008

A coevolutionary model is discussed that incorporates the logical structure of constitutional chemistry and its kinetics on the one hand and the topological evolution of the chemical reaction network on the other hand. The motivation for designing this model is twofold. First, experiments that are to provide insight into chemical problems should be expressed in a syntax that remains as close as possible to real chemistry. Second, the study of physical properties of the complex chemical reaction networks requires growing models that incorporate features realistic from a biochemical perspective. In this article the theory and algorithms underlying the coevolutionary model are explained, and two illustrative examples are provided. These examples show that one needs to be careful in making general claims concerning the structure of chemical reaction networks.
Swarm Chemistry
Authors: Sayama Hiroki
Published: October 2008

We propose swarm chemistry, a new artificial chemistry framework that uses artificial swarm populations as chemical reactants. Reaction in swarm chemistry is not determined by predefined reaction rules as commonly assumed in typical artificial chemistry studies, but is spontaneously achieved by the emergence of a new spatiotemporal pattern of collective behavior through the kinetic interaction between multiple chemical species. We developed a prototype of an interactive simulation tool with which one can explore the dynamics of swarm chemistry using an interactive evolutionary method. Several preliminary results are reported to illustrate the characteristics and effectiveness of this framework, including spontaneous segregation of distinct chemical species, production and restriction of movements, and interactive design of complex biological-looking structures.
Distinct Orbitofrontal Regions Encode Stimulus and Choice Valuation
Authors: Cunningham William A. , Kesek Amanda , Mowrer Samantha M.
Published: October 2008

The weak axiom of revealed preferences suggests that the value of an object can be understood through the simple examination of choices. Although this axiom has driven economic theory, the assumption of equation between value and choice is often violated. fMRI was used to decouple the processes associated with evaluating stimuli from evaluating one's actions. Whereas activity in left posterior areas of the orbitofrontal cortex (OFC) was associated with processing the objective value of stimuli, activity in medial anterior areas of the OFC was associated with accepting high value gambles and rejecting low value gambles; that is, making correct decisions. These data demonstrate that distinct areas of the OFC provide dissociated representations for use in adaptive decision-making and suggest an important processing distinction between the concepts of good/bad and right/wrong.
Neurophysiological Correlates of Comprehending Emotional Meaning in Context
Authors: Holt Daphne J. , Lynn Spencer K. , Kuperberg Gina R.
Published: October 2008

Although the neurocognitive mechanisms of nonaffective language comprehension have been studied extensively, relatively less is known about how the emotional meaning of language is processed. In this study, electrophysiological responses to affectively positive, negative, and neutral words, presented within nonconstraining, neutral contexts, were evaluated under conditions of explicit evaluation of emotional content (Experiment 1) and passive reading (Experiment 2). In both experiments, a widely distributed Late Positivity was found to be larger to negative than to positive words (a “negativity bias”). In addition, in Experiment 2, a small, posterior N400 effect to negative and positive (relative to neutral) words was detected, with no differences found between N400 magnitudes to negative and positive words. Taken together, these results suggest that comprehending the emotional meaning of words following a neutral context requires an initial semantic analysis that is relatively more engaged for emotional than for nonemotional words, whereas a later, more extended, attention-modulated process distinguishes the specific emotional valence (positive vs. negative) of words. Thus, emotional processing networks within the brain appear to exert a continuous influence, evident at several stages, on the construction of the emotional meaning of language.
The Return of Images: Photographic Inquiries into the Interaction of Light
Authors: Lissel Edgar
Published: October 2008

Edgar Lissel has been using the camera obscura for more than 10 years. He converted a transporter into a mobile pinhole camera and transformed living quarters and museum displays into walk-in pinhole cameras. Since 1999, Lissel has been working with bacteria, using their phototropic properties to produce his images. The bacteria move out of the shadow into the light. In the photographic installations Mnemosyne I and Mnemosyne II, he uses fluorescent color pigments to fix the images. Like a memory, the image is stored and emitted by the pigments.
Landscapes of Feeling, Arenas of Action: Information Visualization as Art Practice
Authors: Corby Tom
Published: October 2008

Discussing his recent artworks alongside those by Abigail Reynolds, Lucy Kimbell and Christian Nold, the author examines emerging phenomena in the digital and wider fine arts whereby information visualization practices are approached as creative media. By laying bare points of convergence and divergence between artistic and scientific approaches, the article develops a number of arguments that show how the pictures produced by information visualization may be reframed within wider aesthetic and critical frameworks. Thus the author explores how models of image production derived from processes of scientific inquiry expand possibilities for the visual arts to develop new types of hybrid images that consist of data grounded both in material realities and in symbolic and aesthetic elements.
Impact of Race and Welfare Reform on African American Single Mothers’ Access to Higher Education
Authors: Johnson Vanessa D.
Published: October 2008

This article explores the impact of welfare reform policies on African American college students who are single mothers and how race plays a key role in shaping such policies and college access.
A Hybrid Driving Simulator with Dynamics-Driven Motion and Data-Driven Motion
Authors: Cha Moohyun , Yang Jeongsam , Han Soonhung
Published: October 2008

In driving simulator technology, which reproduces the sense of motion in a virtual reality environment, various research activities are attempting to enhance realism. Recently studies have focused on a data-driven method of generating motion; this method records the motions of real objects and regenerates them in a simulation system. By providing a simulator with real motion data, this method can easily guarantee realism without complicated dynamics models and equation solvers. This paper proposes a hybrid method of generating controllable motion in a driving simulator through the application of a data-driven motion generation method and a dynamics-based motion generation method. The driving data acquired from a real vehicle are parsed into motion blocks with a dynamic model of the vehicle; the motion blocks are then stored in the database. In real-time simulation, a natural motion stream is generated by a process of searching for and synthesizing optimal motion blocks from the database and is synthesized with dynamics-based motion again. A more realistic sense of motion can be generated by parameterizing the current simulation state and user requirements.
English Dialect “Default Singulars,” Was versus Were, Verner's Law, and Germanic Dialects
Authors: Trudgill Peter
Published: October 2008

A current suggestion in the variationist literature is that the predominance of forms like we was in nonstandard varieties of English is predictable in that was-generalization represents a case of the “default singular.” I argue that while the principle of the default singular is a sound one, it is not appropriate as an explanation for was-generalization. What is involved is not a matter of singular versus plural but of r-forms of the past tense of to be versus s-forms, with forms like were, war , wor representing the r-variant and was, wiz , wus the s-variant. The ancient Germanic s/r alternation has been leveled out in most dialects over the past millennium. Examination of Germanic dialects shows that in very many cases, it is the r-forms that have survived. If some general principle were at work, we would expect s-forms to predominate. The history of the Germanic dialects as a whole shows that we are dealing with analogical leveling that does not especially favor either the s-forms or the r-forms. The term default singular has no explanatory value in this case.
Big Five personality traits and relationship quality: Self-reported, observational, and physiological evidence
Authors: Holland Ashley S. , Roisman Glenn I.
Published: October 2008

This report explored links between Big Five personality traits and the quality of romantic relationships. Interpersonal functioning was operationalized at three levels of analysis (self-reported quality, observed emotional tone, and physiological reactivity) in three samples (dating, engaged, and married couples). Couples completed questionnaires about their own and partners' personalities and then discussed a disagreement in their relationship while being physiologically monitored. Two conceptual frameworks were examined; the first predicted that personality would be consistently associated with all indicators of functioning. The second framework predicted that personality would be consistently linked to perceived quality and trivially associated with observed emotional tone and electrodermal/cardiac reactivity. Significant associations were identified between personality and self-reported quality, and only trivial associations with other indictors.
Polyimides Containing Trans-1,4-cyclohexane unit (III). Ordered Structure and Intermolecular Interaction in s-BPDA/CHDA Polyimide
Authors: Ishii Junichi , Horii Shunichi , Sensui Nobuyuki , Hasegawa Masatoshi , Vladimirov Leonid , Kochi Masakatsu , Yokota Rikio
Published: October 2008

Polyimide (PI) derived from 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) with trans-1,4-cyclohexanediamine (CHDA), i.e., s-BPDA/CHDA was investigated from the viewpoint of ordered structure and intermolecular interaction. Thermodynamic parameters of the model compounds for melting behavior suggested significantly restricted conformational changes in the trans-1,4-cyclohexylene unit and the presence of strong BPDI—BPDI interaction in s-BPDA/CHDA. The effect of diamine structure on the fluorescence yield also supported the presence of the BPDI—BPDI interaction or the BPDI dimer in s-BPDA-based semi-cycloaliphatic PIs. The results of the fluorescence depolarization measurements can be rationalized by a proposed mechanism assuming the presence of the BPDI dimer sites, where the fluorescence of s-BPDA/CHDA occurs by excitation of the lower energy trap sites consisting of the BPDI dimer via excitation energy migration or direct excitation of the dimer. The structure-sensitive infrared band around 550 cm-1 gradually shifted toward higher frequency with simultaneous narrowing with increasing cure temperature, suggesting gradual ordered structure formation in s-BPDA/CHDA. Thermal imidization at 400 °C caused splitting of the C—H stretching band around 2940 cm-1, corresponding to the disappearance of distinct glass transition for the s-BPDA/CHDA system.