bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress along tensile lap-spliced fibre reinforced polymer reinforcing bars in concrete
Authors: Aly Ragi
Published: December 2007

A theoretical study was carried out to investigate stress along tensile lap-spliced spaced or bundled fibre reinforced polymer (FRP) bars in concrete. R. Tepfers developed a mathematical model, which could be applied for any type of reinforcing bar, based on the modulus of displacement theory. The mathematical model can predict the bond stress and stresses in the reinforcing bars and the surrounding concrete. In this paper, the model developed by Tepfers was represented by applying the modulus of displacement theory, and theoretical predictions are compared with the experimental results from testing 16 large-scale concrete beams. Good agreement between the theoretical values and experimental results was observed at three stages of loading. Recommendations for investigating the modulus of displacement from pullout tests have been included. Lastly, the maximum average bond stress of spliced FRP bars can be estimated using the ultimate failure pattern analysis, in which the contributions of the splitting resistance were included.Key words: beams, fibre reinforced polymer (FRP) bars, bundled bars, concrete, tensile lap-splice, pullout tests, modulus of displacement, flexural tests.
Hierarchical Bayes methods for systems with spatially varying condition states
Authors: Maes Marc A , Dann Markus
Published: December 2007

In engineering decision making, we often face problems where the conditions governing certain response models vary spatially. In such cases, the use of hierarchical Bayesian models is often beneficial. Such models are based on a “condition state” vector that is assumed to be conditionally independent given a set of “hyper-parameters.” All other process parameters are then conditional on this state variable vector. Such models can be applied to a large variety of problems where data from various systems or sources need to be spatially “mixed,” such as in deteriorating infrastructure, spatial aspects of corrosion, preference and consequence modeling, and system failure models for large industrial plants. The models are especially useful for performing statistical inference and for updating in the context of life-cycle optimization, optimal inspection, and maintenance planning. A detailed extension is explored that allows for the spatial correlation of the individual “states” given the hyper-parameters. This allows an efficient posterior assessment of high-level upcrossing rates for the purpose of risk analysis.Key words: spatially distributed processes, hierarchical Bayes models, statistical inference for large systems, spatial correlation.
The variation of nitrifying bacterial population sizes in a sequencing batch reactor (SBR) treating low, mid, high concentrated synthetic wastewater
Authors: Li Baikun , Irvin Shannon , Baker Katherine
Published: December 2007

The purpose of this study was to correlate the population size of ammonia-oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) with nitrification performance under various operational conditions (chemical oxygen demand (COD) concentration, dissolved oxygen (DO), and hydraulic retention time (HRT)) and influent allylthiourea (ATU) shock. The AOB (genera Nitrosomonas and Nitrosospira ) and NOB (genera Nitrobacter and Nitrospira ) communities were analyzed using fluorescent in situ hybridization (FISH). Ammonia-oxidizing bacteria and NOB accounted for 6.2 ± 0.9% and 2.5 ± 0.3% in total biomass, respectively. The population sizes of AOB and NOB varied with different levels of COD, DO, and HRT. Nitrosomonas and Nitrospira were dominant under conditions favorable for nitrification, while Nitrosospira outcompeted Nitrosomonas under adverse conditions (low [NH4+], low DO, short HRT, and ATU shock), and Nitrobacter outcompeted Nitrospira at high substrate concentrations (COD and [NH4+]). Under ATU shock that inhibited the oxidation of NH4+ to NO2–, AOB population was substantially reduced with the stepwise increase of ATU dosage, and led to a corresponding decrease of NOB population. There was a discrepancy between nitrifying bacterial populations and their functions. Although AOB outnumbered NOB in all tests and became more dominant at low DO and short HRT, NH4+ oxidation, instead of NO2– oxidation, was the rate-limiting reaction for nitrification and susceptible to the adverse conditions. The study demonstrated the importance of elucidating the shifts of nitrifying bacterial population to optimize process design and operation at different influent characteristics, aeration intensity, retention time, and potential influent toxic shock.
Development of a vertical TDR probe to evaluate the vertical moisture profile in peat columns to assess biological clogging
Authors: Zhang Xiaoyang , Van Geel Paul J.
Published: December 2007

Time domain reflectometry (TDR) is used to monitor the moisture content in soils including peat. The objective of this study was to develop a TDR-based method to measure the vertical moisture profile in a peat biofilter operating in the field, where access to the filter is limited to the top surface. The moisture profile with depth can then be used to infer or assess the operating status of a filter in terms of clogging. The successful application of water content measurement using horizontal TDR probes has been demonstrated by many researchers. In this study, a single TDR probe was sequentially advanced into a peat column to estimate the vertical moisture profile and the results were compared to horizontal TDR and gravimetric measurements. The experiment was carried out in six peat columns during a drainage process and two columns during a clogging process. Water contents by the vertical and horizontal probes agreed very well, although the data was slightly more scattered in the columns subject to clogging due to signal attenuation. Total signal attenuation was observed with longer probes in clogged peat soils. However, there was a consistent discrepancy between the TDR measured water contents and those determined gravimetrically, which is believed to be caused by a systematic error, possibly error with the calibration curve.
Performance evaluation, comparison and modeling of passive wastewater treatment systems
Authors: Martin D.G. , Anderson B.C.
Published: December 2007

The objectives of this research were to evaluate and compare five configurations of wastewater treatment for on-site or communal applications in various climate conditions: a peat filter, a sand filter, a subsurface flow constructed wetland cell, a peat filter followed by a wetland cell, and a sand filter followed by a wetland cell. Oxygen demand, nitrogen and phosphorus compounds, temperature, and indicator bacteria of the influent and effluent of each treatment stage were monitored over a period of 17 months. The sand and peat filters achieved over 98% reduction in carbonaceous biochemical oxygen demand (CBOD5) to <1 mg/L (below detection limits) in most samples. The filters also reduced all indicator bacteria parameters to low levels. Phosphorus removal through the sand filter consistently exceeded 98% but declined rapidly after 14 months, likely due to saturation. Phosphorus reduction in the peat filter averaged 47% with an additional 58% provided by the wetland cell (total 78%);; no saturation trend was apparent by the 17th month. The total nitrogen reductions were low initially but improved over time in both filters. The wetland cell provided low to moderate treatment efficiencies for CBOD5(49%), phosphorus (33%), indicator bacteria (~2 log reduction), and total nitrogen (31%).
Pressurized water versus ethanol as a Silybum marianum extraction solvent for inhibition of low-density lipoprotein oxidation mediated by copper and J774 macrophage cellsThis article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Wallace Sunny N. , Raible Jennifer , Carrier Danielle Julie , Vaughn Katherine L. , Griffis Carl L. , Clausen Edgar C. , Nagarajan Shanmugam
Published: December 2007

Silybum marianum contains flavonolignans, termed silymarin (SM), that are therapeutic agents for many inflammation-based diseases including atherosclerosis. Oxidation of human low-density lipoprotein was induced by CuSO4 or J774 macrophage cells and measured by the formation of thiobarbituric acid reactive substances (TBARS). SM was extracted by pressurized hot water (PHWE) or ethanol, and the effects of these extracts on TBARS formation were evaluated in comparison with those of SM preparations made from blending masses of individual flavonolignan standards in ratios identical to those of the water and ethanol extracts. Ethanol-extracted SM and its blended counterpart inhibited the generation of TBARS by 82% and 43%, respectively, at 150 μmol/L doses. TBARS levels in the presence of 150 μmol/L of the PHWE and its blended SM counterpart were reduced by 84% and 38%, respectively. Extracts from milk thistle fruit displayed higher protective effects than blended SM solutions of the same concentration with an identical compositional makeup. The appearance of degradation peaks in the water extract did not create any cytotoxic effects. Results of this study confirm that PHWE can be used to extract flavonolignans from milk thistle and that these extracts may possess therapeutic potential different from or beyond that of traditional organic solvent preparations.
In vitro evaluation of the antiviral effects of the homeopathic preparation Gripp-Heel on selected respiratory virusesThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Glatthaar-Saalmüller Bernadette
Published: December 2007

Gripp-Heel®is a homeopathic preparation frequently used in the treatment of respiratory viral infections such as various types of influenza and the common cold. The antiviral activity of Gripp-Heel was studied in vitro on human pathogenic enveloped and nonenveloped RNA and DNA viruses. Before the antiviral assays, in vitro cytotoxicity of Gripp-Heel was determined with cells used for the infection experiments (HeLa, HEp-2, MDCK, BGM) as well as with mitogen-stimulated peripheral blood mononuclear leukocytes. A concentration of 0.5 of the commercially available product slightly reduced cell viability and proliferative capacity, and experiments on antiviral activity were determined starting with a dilution of 0.2 of the commercially available product. The antiviral activity was determined against a broad panel of enveloped and nonenveloped DNA and RNA viruses with plaque reduction assay, cytopathogenic assays, virus titrations, analysis of the viral proteins in virus-specific enzyme immunoassays, and haemagglutination tests. Control substances were acyclovir (10 μg/mL), ribavirin (6 μg/mL), and amantadine hydrochloride (5 μg/mL), depending on the virus type. Gripp-Heel demonstrated dose-dependent in vitro activity (significant reductions of infectivity by 20% to 40%) against Human herpesvirus 1, Human adenovirus C serotype 5, Influenza A virus, Human respiratory syncytial virus, Human parainfluenza virus 3, Human rhinovirus B serotype 14, and Human coxsackievirus serotype A9. The mechanisms of this antiviral activity are still unclear, but type I interferon induction might be a possible explanation. Further research on this homeopathic preparation seems warranted.
Modulation of immune response gene expression by echinacea extracts: results of a gene array analysisThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Altamirano-Dimas M. , Hudson J. B. , Cochrane D. , Nelson C. , Arnason J. T.
Published: December 2007

Echinacea extracts have traditionally been used in the treatment of many infectious and other diseases (such as rhinovirus colds), and research has revealed the presence of various bioactivities in these extracts, particularly those connected with immune responses. We examined the effects of Echinacea by using gene expression analysis in a line of human bronchial epithelial cells, with or without rhinovirus infection. More than 13 000 human genes were evaluated. From these analyses we focused primarily on immune response genes and found that both Echinacea extracts, one predominantly rich in polysaccharides and the other rich in alkylamides and caffeic acid derivatives, stimulated the expression of numerous genes. These included a number of cytokines and chemokines, although the pattern of stimulation was different. In addition, Echinacea extracts tended to neutralize the effects of the rhinovirus. When the immune response gene pathways were analyzed with the Ingenuity Pathway program, it became apparent that many of them were interconnected through a major node, the transcription factor C/EBPβ (CAAT/enhancer-binding protein β) and its related C/EBP proteins. This suggests that Echinacea can bring about important biological responses in cells by virtue of interactions between components of the extract and a small number of intracellular factors involved in multiple signaling pathways.
Adventures in drug disposition: pas seulement pâté de foie
Authors: Sitar Daniel S.
Published: December 2007

Interindividual variability in drug disposition and effect has served to confound the optimization of drug therapy. Over my career, I have focused on delineating mechanisms that contribute to this variability, with the goal of improving the benefit : risk ratio when drug therapy is chosen as an intervention strategy. In this manuscript, I present some of our experimental findings that I believe have contributed to an increased understanding of variability in drug disposition and efficacy.
Soil as an important interface between agricultural activities and groundwater: leaching of nutrients and pesticides in the vadose zone
Authors: Bergström L. F. , Djodjic F.
Published: December 2007

Agricultural non-point source pollution by plant nutrients and pesticides can cause severe environmental disturbances, such as deterioration in the quality of surface water and groundwater. In order to prevent this, the development and implementation of appropriate countermeasures are necessary, which requires knowledge of critical soil functions in the vadose zone. The nutrient source, the transport pathway and the availability of solutes in soil are some important conditions that affect leaching. Our results show that organic nitrogen sources are often more susceptible to leaching than inorganic N fertilizers, due to poor synchronization between the N demand of the crop and the release of inorganic N from the organic N source. Large amounts of leachable N are left in the soil after the growing season. Preferential flow, in combination with where soil solutes occur, is critical for establishing safe loading rates. In some cases, the solute is located in smaller pores of the soil matrix, and is thereby protected against preferential flow and leaching. In other cases, especially soon after application of a fertilizer or pesticide, transient flow-peaks rapidly displace the solutes through macropores in the vadose zone, which can cause large leaching loads and associated water-quality problems.
Heavy metals in Swiss forest soils: modification of lithogenic and anthropogenic contents by pedogenetic processes, and implications for ecological risk assessment
Authors: Luster Jöorg , Zimmermann Stephan , Zwicky Christoph N. , Lienemann Peter , Blaser Peter
Published: December 2007

We investigated the occurrence and effective mobility of heavy metals (HM) in a representative collective of Swiss forest soils. The total HM contents of pedogenetic horizons were analysed, and the enrichment or depletion of a given HM relative to the original lithogenic content was assessed. The latter was calculated using the contents of Zr as an immobile reference. Chromium, Ni, Cu and Zn were mainly lithogenic, with a wide range of contents reflecting the diverse geology of Switzerland, while anthropogenic input of Pb was detected in most topsoils. Pedogenetic processes exerted a strong influence on the translocation or leaching of the HM. In acidic soils Ni, Cu and Pb were more mobile than Cr and Zn. We relate this behaviour to the strong affinity of the former HM to dissolved or colloidal organic matter. On the other hand, nutrient cycling by the vegetation probably led to an apparent reduction of Zn downward mobility. In many soils, guide levels as specified by Swiss legislation, or threshold values for effects on micro-organisms, were exceeded, indicating a potential risk for long-term soil fertility. As a consequence of translocation, guide levels for Cr, Ni and Cu were exceeded more often in subsoils than in topsoils.
Reuse of agricultural drainage water in central California: phytosustainability in soil with high levels of salinity and toxic trace elements
Authors: Bañuelos G. S. , Lin Z.-Q.
Published: December 2007

Agricultural drainage waters in the western San Joaquin Valley of Central California contained high levels of salts, boron (B) and selenium (Se). Discharge of the drainage directly into the Kesterson Reservoir was hazardous to plants and wildlife. To investigate the plausibility of using plants as recipients for disposing of poor-quality drainage-waters, multi-year field studies were conducted to reuse drainage water on plants that are salt and B tolerant, and accumulate or stabilize soluble Se from the drainage. Installation of a subsurface tile drainage system in cropping fields allowed drainage waters to be collected and subsequently reused on tolerant plants. The tested plant species included
Lactuca sativa, Lycopersicon esculentum, Gossypium hirsutum
L.,
Medicago sativa
L.,
Brassica napus
var. Hyola,
Helianthus annuus, Distichlis spicata
L., and
Salicornia bigelovii
Torr. The quality of drainage water decreased along the water reuse path, with a sulphate-dominated salinity change from 4.5 to 15.2 dS m
-1
; soluble B from 3.4 to 14.5 mg L
-1
; and soluble Se from 0.08 to 1.18 mg L
-1
. Soil salinity and concentrations of B and Se increased with decreasing quality of reused drainage waters. This study demonstrated the importance of monitoring changes in soil quality for sustaining such a plant-based system.
Assessing anthropogenic inputs to soils by comparing element contents and their spatial distribution in O- and A-horizons
Authors: Inácio M. , Pereira V. , Pinto M.
Published: December 2007

This paper reports the results of a low-density geochemical survey covering the entire surface of Portugal, taking organomineral horizons (A) and organic horizons (humus, O) as the sampling media. The main purpose of the study was to compare element contents and their spatial variability in the two soil horizons in order to distinguish between natural and anthropogenic inputs. Contents are compared using an index of enrichment, IE = (content in O in mg kg
-1
)/(content in A in mg kg
-1
) and the IE maps are used to discuss the origin of the elements. It was found that element contents in the upper horizons of Portuguese soils are controlled by the nature of the parent material, pedogenetic processes and anthropogenic additions. Our approach, evidencing spatial relationships, proved useful to the confirmation and refinement of the information obtained from biomonitoring surveys. Another advantage is a significant reduction in sampling costs, because by comparing the two uppermost soil horizons there is no need for sampling to great depths.
Seismic imaging for seismic geomorphology beyond the seabed: potentials and challenges
Authors: Zeng H.
Published: December 2007

A successful study of seismic geomorphology depends not only on knowledge of sedimentological, geomorphological principles and the local geological setting, but also on quality of the seismic geomorphological imaging. A thorough understanding of how seismic waves respond to geomorphology of depositional sequences and facies is essential prior to developing strategies and selecting tools for field seismic data interpretation. This is especially important in data that are of variable quality or lack marked amplitude anomalies. Studies presented in this paper show that it is more desirable to use stratal slices to display seismic information on geological time surfaces. Multi-slice or movie display of stratal slices is effective for the study of depositional process and is a good quality-control tool for avoiding seismic artifacts. Seismic wavelets adjusted to 90° phase help tie seismic traces to lithofacies with higher stratigraphic resolution. Seismic frequency bands of stratal slices should match the lithofacies thickness of interest for optimal facies imaging. Seismic facies analysis can be improved by automated geomorphological classification.
Curvature for visualization of seismic geomorphology
Authors: Hart B. S. , Sagan J. A.
Published: December 2007

We illustrate the use of curvature attributes for defining stratigraphic features of interest on horizons mapped in three-dimensional seismic data. Curvature is a two-dimensional property of a curve that quantifies how much the curve deviates from a straight line. Many different types of curvature may be defined for a surface, and these can be more useful than dip, azimuth or even ‘conventional’ (i.e. second derivative) curvature analyses for defining subtle structural or stratigraphic features of interest. In our workflow, we drape curvature over rendered three-dimensional surfaces and adjust lighting to highlight stratigraphic and structural features of interest. The examples we present are derived from clastic and carbonate settings of various ages, and include applications of curvature analyses to multibeam bathymetry and digital elevation model data.
Geometry and seismic geomorphology of carbonate shoreface clinoforms, Jurassic Smackover Formation, north Louisiana
Authors: Handford C. R. , Baria L. R.
Published: December 2007

Across much of the Gulf Coast basin of the USA, the Smackover Formation consists of a nearly 100m-thick shoaling upward cycle capped by oolitic/oncolitic packstones and grain-stones. It has long been interpreted as a homoclinal ramp succession, which was analogous to the modern example in the southeastern Arabian Gulf. In a three-dimensional seismic survey in north Louisiana, the shoaling-upward cycle is imaged as basin ward progradational clinoforms (4–7° inclination) with well-defined toplap and downlap surfaces. In map view, amplitude slices show that the clinoform bodies are strike-oriented and continuous. The inclination and width of the clinoform bodies indicate that water depths of up to 90 m were present within 1 km of the shoreline. Such characteristics indicate that the Smackover Formation cannot be classified as a homoclinal ramp in north Louisiana and that the Arabian Gulf is not analogous to the Smackover.
Early evolution of submarine channels offshore Angola revealed by three-dimensional seismic data
Authors: Gee M. J. R. , Gawthorpe R. L.
Published: December 2007

The deep-water subsurface offshore Angola is characterized by many linear, high-gradient submarine channels typically only tens of metres wide and deep. Larger channel systems (
C.
3–5 km wide, >300 m deep) with highly sinuous channels at their bases are also common, although they appear to have evolved from small, linear, high gradient systems. Generally, such small linear channels become enlarged by sediment gravity flows and therefore are rarely preserved except in examples where avulsion occurs. These small linear systems are often associated with relatively continuous levees 1–3 km wide flanking the channel. Results presented here suggest that small, linear channels evolve from erosional lineations on the slope generated by large, infrequent turbidity currents. Results also indicate that linear, high-gradient channels also exhibit the most significant and distinctive geometry changes where there is complex topography, such as near salt structures. Sedimentary bodies associated with linear, high-gradient channels often deposit within slope depressions as discreet J- or S-shaped structures in plan view. The dominant control on these sedimentary bodies is interpreted to be seafloor gradient and topography. This paper examines a number of these relatively young channels in terms of their geometry, gradient, levee development and seismic facies. The results improve our ability to predict subsurface channel geometries and recognise key evolutionary trends.
Heap reference analysis using access graphs
Authors: Khedker Uday P. , Sanyal Amitabha , Karkare Amey
Published: December 2007

Despite significant progress in the theory and practice of program analysis, analyzing properties of heap data has not reached the same level of maturity as the analysis of static and stack data. The spatial and temporal structure of stack and static data is well understood while that of heap data seems arbitrary and is unbounded. We devise bounded representations that summarize properties of the heap data. This summarization is based on the structure of the program that manipulates the heap. The resulting summary representations are certain kinds of graphs called
access graphs
. The boundedness of these representations and the monotonicity of the operations to manipulate them make it possible to compute them through data flow analysis.

An important application that benefits from heap reference analysis is garbage collection, where currently liveness is conservatively approximated by reachability from program variables. As a consequence, current garbage collectors leave a lot of garbage uncollected, a fact that has been confirmed by several empirical studies. We propose the first ever end-to-end static analysis to distinguish live objects from reachable objects. We use this information to make dead objects unreachable by modifying the program. This application is interesting because it requires discovering data flow information representing complex semantics. In particular, we formulate the following new analyses for heap data: liveness, availability, and anticipability and propose solution methods for them. Together, they cover various combinations of directions of analysis (i.e., forward and backward) and confluence of information (i.e. union and intersection). Our analysis can also be used for plugging memory leaks in C/C++ languages.
Forma
Authors: Zhao Peng , Cui Shimin , Gao Yaoqing , Silvera Raúl , Amaral José Nelson
Published: December 2007

This article presents
Forma
, a practical, safe, and automatic data reshaping framework that reorganizes arrays to improve data locality.
Forma
splits large aggregated data-types into smaller ones to improve data locality. Arrays of these large data types are then replaced by multiple arrays of the smaller types. These new arrays form natural data streams that have smaller memory footprints, better locality, and are more suitable for hardware stream prefetching.
Forma
consists of a field-sensitive alias analyzer, a data type checker, a portable structure reshaping planner, and an array reshaper. An extensive experimental study compares different data reshaping strategies in two dimensions: (1) how the data structure is split into smaller ones (
maximal partition
×
frequency-based partition
×
affinity-based partition
); and (2) how partitioned arrays are linked to preserve program semantics (
address arithmetic-based reshaping
×
pointer-based reshaping
). This study exposes important characteristics of array reshaping. First, a practical data reshaper needs not only an inter-procedural analysis but also a data-type checker to make sure that array reshaping is safe. Second, the performance improvement due to array reshaping can be dramatic: standard benchmarks can run up to 2.1 times faster after array reshaping. Array reshaping may also result in some performance degradation for certain benchmarks. An extensive micro-architecture-level performance study identifies the causes for this degradation. Third, the seemingly naive maximal partition achieves best or close-to-best performance in the benchmarks studied. This article presents an analysis that explains this surprising result. Finally, address-arithmetic-based reshaping always performs better than its pointer-based counterpart.
Efficient dynamic dispatching with type slicing
Authors: Gil Joseph (Yossi) , Zibin Yoav
Published: December 2007

A fundamental problem in the implementation of object-oriented languages is that of a frugal implementation of dynamic dispatching, that is, a small footprint data structure that supports quick response to runtime dispatching queries of the following format: which method should be executed in response to a certain message sent to a given object. Previous theoretical algorithms for this problem tend to be impractical due to their conceptual complexity and large hidden constants. In contrast, successful practical heuristics lack theoretical support.

The contribution of this article is in a novel
type slicing
technique, which results in two dispatching schemes: TS and CT

d

. We make the case for these schemes both practically and theoretically. The empirical findings on a corpus of 35 hierarchies totaling some 64 thousand types from eight different languages, demonstrate improvement over previous results in terms of the space required for the representation, and the time required for computing it.

The theoretical analysis is with respect to ι, the best possible compression factor of the dispatching matrix. The results are expressed as a function of a parameter κ, which can be thought of as a metric of the complexity of the topology of a multiple inheritance hierarchy. In single inheritance hierarchies κ = 1, but although κ can be in the order of the size of the hierarchy, it is typically a small constant in actual use of inheritance; in our corpus, the median value of κ is 5, while its average is 6.4.

The TS scheme generalizes the famous interval containment technique to multiple inheritance. TS achieves a compression factor of ι/κ, that is, our generalization comes with an increase to the space requirement by a small factor of κ. The pay is in the dispatching time, which is no longer constant as in a naive matrix implementation, but logarithmic in the number of different method implementations. In practice, dispatching uses one indirect branch and, on average, only 2.5 binary branches.

The CT schemes are a sequence of algorithms CT
1
, CT
2
, CT
3
, …, where CT

d

uses
d
memory dereferencing operations during dispatch, and achieves a compression factor of 1/
d
ι

1−1/
d

in a
single inheritance
setting. A generalization of these algorithms to a
multiple inheritance
setting, increases the space by a factor of (2κ)

1−1/
d

. This trade-off represents the first bounds on the compression ratio of constant-time dispatching algorithms. We also present an
incremental
variant of the CT

d

suited for languages such as Java.
On specification of Read/Write shared variables
Authors: Haldar Sibsankar , Vidyasankar K.
Published: December 2007

A shared variable is an abstraction of persistent interprocess communication. Processors execute operations, often concurrently, on shared variables to exchange information among themselves. The behavior of operation executions is required to be “consistent” for effective interprocess communication. Consequently, a consistency specification of a shared variable describes some guarantees on the behavior of the operation executions. A Read/Write shared variable has two operations: a Write stores a specified value in the variable and a Read returns a value from the variable. For Read/Write variables, a consistency specification describes what values Reads may return. Using an intuitive notion of illegality of Reads, we propose a framework that facilitates specifying a large variety of Read/Write variables.
Kyu-Young Whang speaks out
Authors: Winslett Marianne
Published: December 2007

Welcome to this installment of ACM SIGMOD Record's series of interviews with distinguished members of the database community. I'm Marianne Winslett, and today we are at the ICDE 2007 Conference in Istanbul. I have here with me Kyu-Young Whang, who is a professor of computer science at Korea Advanced Institute of Science and Technology, and the director of the Advanced Information Technology Research Center. Before joining KAIST, Kyu-Young was a member of technical staff at IBM TJ Watson Research Center. His research interests are very broad, encompassing many different kinds of database systems as well as data mining and data streaming. He is an editor-in-chief of the VLDB Journal, a former member of the VLDB Endowment, and an IEEE Fellow. Kyu-Young's PhD is from Stanford. So, Kyu-Young, welcome!
Introduction
Authors: Hemaspaandra Lane A.
Published: December 2007

Warmest thanks to Salil Vadhan for this issue's wonderful guest column on pseudorandomness. (His column begins in a few pages.) Future columns include Arnaud Durand, Clemens Lautemann, and Malika More on A Simple Proof of Polylog Counting Ability of First-Order Logic, Jonathan Buss and Tarique Islam on Complexity of Fixed-Parameter Problems, and Jin-Yi Cai on holographic algorithms.
The unified theory of pseudorandomness
Authors: Vadhan S.
Published: December 2007

We survey the close connections between a variety of "pseudorandom objects," namely pseudorandom generators, expander graphs, list-decodable error-correcting codes, randomness extractors, averaging samplers, and hardness amplifiers.
Entomological Reactions to Darwin's Theory in the Nineteenth Century
Authors: Kritsky Gene
Published: December 2007

Charles Darwin first became interested in entomology during his childhood, and this interest grew into a beetle-collecting obsession during his college days. Following the voyage of the Beagle, his focus on insects shifted from collecting specimens to searching for insect observations that supported his theory of natural selection as proposed in On the Origin of Species. Initially, Darwin believed that entomologists were opposed to his views. Using Darwin's correspondence, I show that his perception was based, in part, on three reviews, including one that he erroneously attributed to an entomological critic, and that not all entomologists were opposed to his ideas. Henry Walter Bates, discoverer of Batesian mimicry, voiced his support of Darwin in his papers and during meetings of the (now Royal) Entomological Society. In America, entomologist Benjamin D. Walsh wrote to Darwin in 1864, expressing his support and promising to counter any anti-Darwinian attack, and by 1868, Darwin was enjoying significant entomological support on both sides of the Atlantic. After his death in 1882, Darwin's supporters gained influence in Britain and the United States, completing entomology's shift to a Darwinian perspective.
Time Since Menopause Influences the Acute and Chronic Effect of Estrogens on Endothelial Function
Authors: Vitale Cristiana , Mercuro Giuseppe , Cerquetani Elena , Marazzi Giuseppe , Patrizi Roberto , Pelliccia Francesco , Volterrani Maurizio , Fini Massimo , Collins Peter , Rosano Giuseppe M.C.
Published: December 2007

Objective—

We evaluated whether time since menopause influences the acute and chronic effect of Estradiol (E) on vascular endothelial function.

Methods and Results—

We studied flow-mediated dilatation (FMD) in 134 postmenopausal women (PMW) before and after acute and chronic E administration. At baseline FMD was inversely associated to time from menopause (
r
=−0.67,
P
<0.001) and age (
r
=−0.43,
P
<0.05), in exogenous estrogen naïve but not in previous users. Acute and chronic E improved endothelial function in all women. E administration improved FMD more in women within 5 years since menopause than in those with more than 5 years since menopause (76% and 74% versus 45% and 48%, acute and chronic E, respectively;
P
<0.05). Among women with more than 5 years since menopause acute and chronic E increased FMD more in previous E users than in nonusers (59% and 63% versus 31% and 38%, acute and chronic E, respectively;
P
<0.01). Multivariate analysis showed that time from menopause was a predictor of impaired FMD and of its improvement after acute and chronic E.

Conclusions—

Time from menopause influences FMD in PMW. The acute and chronic effect of E on FMD is time dependent and is reduced by a longer time since menopause.
Rapid Assessment of Perfusion–Diffusion Mismatch
Authors: Butcher Ken , Parsons Mark , Allport Louise , Lee Sang Bong , Barber P. Alan , Tress Brian , Donnan Geoffrey A. , Davis Stephen M.
Published: December 2007

Background and Purpose—

For MR perfusion–diffusion (PWI-DWI) mismatch to become routine in thrombolysis patient selection, rapid and reliable assessment tools are required. We examined interrater variability in PWI/DWI volume measurements and developed a rapid assessment tool based on the Alberta Stroke Program Early CT Scores (ASPECTS) system.

Methods—

DWI and PWI were performed in 35 patients with stroke <6 hours after symptom onset. DWI lesion and PWI (time to peak) volumes were measured with planimetric techniques by 4 raters and the 95% limits of agreement calculated. ASPECT scores were assessed separately by 4 investigators (2 experienced and 2 inexperienced) for DWI (MR DWI scores) and PWI (MR time to peak scores). MR mismatch scores were calculated as MR DWI-MR time to peak scores.

Results—

Interobserver variability was much greater for PWI (95% limit of agreement=±72.3 mL) than for DWI (95% limit of agreement=±12.6 mL). A semiautomated PWI volume (time to peak+2 s) was therefore used to calculate mismatch volume. MR mismatch scores ≥2 predicted 20% PWI-DWI mismatch by volume with mean 78% sensitivity (range, 72% to 84%) and 88% specificity (range, 83% to 90%). There was excellent agreement on mismatch classification using MR mismatch scores between experienced raters (weighted kappa scores of 0.94) with agreement in 34 of 35 cases. Agreement was less consistent between inexperienced raters (weighted kappa=0.49, 28 of 35 cases).

Conclusions—

Variability in planimetric mismatch measurements arises primarily from differences in PWI volume assessment. High specificity and interrater reliability may make MR mismatch scores an ideal rapid screening tool for potential thrombolysis patients.
Atorvastatin Promotes Presenilin-1 Expression and Notch1 Activity and Increases Neural Progenitor Cell Proliferation After Stroke
Authors: Chen Jieli , Zacharek Alex , Li Ang , Cui Xu , Roberts Cynthia , Lu Mei , Chopp Michael
Published: December 2007

Background and Purpose—

Presenilin1 (PS1) regulates Notch1 signaling activity, which liberates Notch intracellular domain (NICD). Notch activation promotes neural progenitor cell (NPC) self-renewal in the developing brain. In this study, we tested whether atorvastatin-induced NPC proliferation after stroke is mediated by PS1 and Notch1 activation.

Methods—

PS1 and NICD expressions were measured in retired breeder rats subjected to middle cerebral artery occlusion that were left untreated or treated with atorvastatin. To investigate the mechanisms of atorvastatin-induced NPC self-renewal, subventricular zone (SVZ) neurosphere culture and knockdown of Notch1 gene expression by short interfering RNA were used. SVZ neurosphere formation, cell proliferation, real-time polymerase chain reaction, and Western blotting were performed.

Results—

Atorvastatin significantly increased the numbers of newly generated neuroblasts and promoted PS1 and NICD expression in the ipsilateral and homologous contralateral SVZ compared with saline-treated control rats. Increased SVZ neurosphere formation and cell proliferation were found in cultured neurospheres derived from normal rat and poststroke rat SVZs treated in vitro with atorvastatin compared with untreated neurospheres (
P
<0.05). Atorvastatin significantly increased PS1 and hairy and enhancer of split1 (Hes1) gene expression in cultured SVZ neurospheres. Inhibition of PS1 significantly decreased NICD expression. Short interfering RNA knockdown of Notch1 expression, decreased NPC proliferation, and NICD and hairy and enhancer of split1 expression in cultured neurosphere cells.

Conclusions—

These data indicate that atorvastatin increases the NPC pool in older rats and that it also upregulates PS1 expression and Notch1 signaling activity, which in turn, facilitate an increase in SVZ NPC proliferation.
Metabolic Syndrome and Ischemic Stroke Risk
Authors: Boden-Albala Bernadette , Sacco Ralph L. , Lee Hye-Sueng , Grahame-Clarke Cairistine , Rundek Tanja , Elkind Mitchell V. , Wright Clinton , Giardina Elsa-Grace V. , DiTullio Marco R. , Homma Shunichi , Paik Myunghee C.
Published: December 2007

Background and Purpose—

More than 47 million individuals in the United States meet the criteria for the metabolic syndrome. The relation between the metabolic syndrome and stroke risk in multiethnic populations has not been well characterized.

Methods—

As part of the Northern Manhattan Study, 3298 stroke-free community residents were prospectively followed up for a mean of 6.4 years. The metabolic syndrome was defined according to guidelines established by the National Cholesterol Education Program Adult Treatment Panel III. Cox proportional-hazards models were used to calculate hazard ratios (HRs) and 95% CIs for ischemic stroke and vascular events (ischemic stroke, myocardial infarction, or vascular death). The etiologic fraction estimates the proportion of events attributable to the metabolic syndrome.

Results—

More than 44% of the cohort had the metabolic syndrome (48% of women vs 38% of men,
P
<0.0001), which was more prevalent among Hispanics (50%) than whites (39%) or blacks (37%). The metabolic syndrome was associated with increased risk of stroke (HR=1.5; 95% CI, 1.1 to 2.2) and vascular events (HR=1.6; 95% CI, 1.3 to 2.0) after adjustment for sociodemographic and risk factors. The effect of the metabolic syndrome on stroke risk was greater among women (HR=2.0; 95% CI, 1.3 to 3.1) than men (HR=1.1; 95% CI, 0.6 to 1.9) and among Hispanics (HR=2.0; 95% CI, 1.2 to 3.4) compared with blacks and whites. The etiologic fraction estimates suggest that elimination of the metabolic syndrome would result in a 19% reduction in overall stroke, a 30% reduction of stroke in women; and a 35% reduction of stroke among Hispanics.

Conclusions—

The metabolic syndrome is an important risk factor for ischemic stroke, with differential effects by sex and race/ethnicity.
‘A Christian Benares’
Authors: Sivasundaram Sujit
Published: December 2007

By using the case of the Baptist missionaries called the ‘Serampore Trio’—Rev. William Carey, Rev. William Ward and Rev. Joshua Marshman—this article urges that science and Christianity were intimately related in early nineteenth-century north India. The Serampore Baptists practised a brand of Christian and constructive orientalism, devoting themselves to the recovery of Sanskrit science and the introduction of European science into India. Carey established an impressive private botanical garden and was instrumental in the formation of the Agricultural Society of India. Ward, in his important account of Hinduism, argued that true Hindu science had given way to empiricism, and that Hindus had confused nature with the divine. The Serampore College formed by the trio sought to educate Indians with respect to both Sanskrit and European science, and utilised a range of scientific instruments and texts on science published in India. The College aimed to change the way its pupils saw the material world by urging experimentation rather than reverence of nature. The style of science practised at Serampore operated outside the traditional framework of colonial science: it did not have London as its centre, and it sought to bring indigenous traditions into a dialogue with European science, so that the former would eventually give way to the latter.
A New Approach to the Metamerism Phenomenon in the Frequency Domain
Authors: Khodadadi S. , Hosseini S.A. , Khalili H.
Published: December 2007

In this investigation, the behavior of crossover points of spectral reflectance of metameric pairs in the frequency domain has been studied. Also the general metameric index has been calculated using a power spectrum by Fourier transformation. Correlation between these results and the results of current methods was studied. Results show that the transformation of spectral reflectance differences of metameric pairs in the frequency domain could be considerable. This new approach is regarded as a useful method to investigate the metamerism phenomenon.
Faith in Education
Authors: Symes Colin , Gulson Kalervo N.
Published: December 2007

Fundamentalist and evangelical Christianity is growing in popularity in Australia, concurrent with the ascendancy of the new Christian school. This article examines the historical and policy landscapes that have given rise to this educational phenomenon and draws some links with other education systems, particularly the United States. It is argued that, in Australia, a propitious setting for the rise of new Christian schools has been created through the interplay of evangelical and fundamentalist Christianity, Australia's Constitution, and an enabling neoliberal policy environment.
The Legislative Median and Partisan Policy
Authors: Wiseman Alan E. , Wright John R.
Published: December 2007

We show that the median legislator in the US House is unambiguously closer to the majority party median than to the minority party median. An important implication of this finding is that the median legislator is predisposed to support the majority party's policy agenda. Thus, in the event that the majority party organization exerts no influence over the legislative process, and in the event that all policies then default to the legislative median, policy outcomes will still substantially favor the majority party over the minority. We demonstrate that the legislative median moves predictably toward the majority party in response to changes in majority control and the size and ideological homogeneity of the two parties. Consequently, the median legislators' partisan predisposition increases and decreases in response to electoral change. We conclude that partisan and floor majority, or median, theories of lawmaking are more often complementary than conflicting, and that party activities in the electoral arena have implications for legislative partisanship.
Senate Elections With Independent Candidates
Authors: Heckelman Jac C. , Yates Andrew J.
Published: December 2007

Assuming strict two-party competition, policy balancing models of the US senate imply that senators from the same state will often be from opposite parties and have great ideological divergence. We analyze the effect of independent candidates on these implications. Our theoretical model implies the two state senators will generally not be from opposite parties and will be closer in ideological space than if they were elected under strict two-party competition. Empirical analysis of senate composition from 1991 to 2002 supports the theory.
Effort, Intensity and Position Taking
Authors: Bawn Kathleen , Koger Gregory
Published: December 2007

Effort is a crucial element of the legislative process — writing bills, forming coalitions, crafting strategies, and debating. We develop a model in which legislative decisions are the product of competitive effort by two teams, one trying to pass new legislation, and the other to block it. Teams choose effort levels based on preferences over the policy outcome, political rewards for effort, and opportunity costs, and the team that produces more effort wins. We apply this model to four cases of major legislation from the pre-cloture Senate: passage of the Federal Reserve Act in 1913, the Ship Purchase Act of 1915, the Ship Arming bill of 1917, and the adoption of the Senate cloture rule in 1917. These cases demonstrate the value of looking beyond legislative voting and the rules that structure it, and of including effort as a key element of the legislative game.