bluuebunny/crossref_metadata_2025 huggingface dataset:
Classification-aware hidden-web text database selection
Authors: Ipeirotis Panagiotis G. , Gravano Luis
Published: April 2008

Many valuable text databases on the web have noncrawlable contents that are “hidden” behind search interfaces. Metasearchers are helpful tools for searching over multiple such “hidden-web” text databases at once through a unified query interface. An important step in the metasearching process is database selection, or determining which databases are the most relevant for a given user query. The state-of-the-art database selection techniques rely on statistical summaries of the database contents, generally including the database vocabulary and associated word frequencies. Unfortunately, hidden-web text databases typically do not export such summaries, so previous research has developed algorithms for constructing
approximate
content summaries from document samples extracted from the databases via querying. We present a novel “focused-probing” sampling algorithm that detects the topics covered in a database and adaptively extracts documents that are representative of the topic coverage of the database. Our algorithm is the first to construct content summaries that include the frequencies of the words in the database. Unfortunately, Zipf's law practically guarantees that for any relatively large database, content summaries built from moderately sized document samples will fail to cover many low-frequency words; in turn, incomplete content summaries might negatively affect the database selection process, especially for short queries with infrequent words. To enhance the sparse document samples and improve the database selection decisions, we exploit the fact that topically similar databases tend to have similar vocabularies, so samples extracted from databases with a similar topical focus can complement each other. We have developed two database selection algorithms that exploit this observation. The first algorithm proceeds hierarchically and selects the best categories for a query, and then sends the query to the appropriate databases in the chosen categories. The second algorithm uses “shrinkage,” a statistical technique for improving parameter estimation in the face of sparse data, to enhance the database content summaries with category-specific words. We describe how to modify existing database selection algorithms to adaptively decide (at runtime) whether shrinkage is beneficial for a query. A thorough evaluation over a variety of databases, including 315 real web databases as well as TREC data, suggests that the proposed sampling methods generate high-quality content summaries and that the database selection algorithms produce significantly more relevant database selection decisions and overall search results than existing algorithms.
Towards a belief-revision-based adaptive and context-sensitive information retrieval system
Authors: Lau Raymond Y. K. , Bruza Peter D. , Song Dawei
Published: April 2008

In an adaptive information retrieval (IR) setting, the information seekers' beliefs about which terms are relevant or nonrelevant will naturally fluctuate. This article investigates how the theory of belief revision can be used to model adaptive IR. More specifically, belief revision logic provides a rich representation scheme to formalize retrieval contexts so as to disambiguate vague user queries. In addition, belief revision theory underpins the development of an effective mechanism to revise user profiles in accordance with information seekers' changing information needs. It is argued that information retrieval contexts can be extracted by means of the information-flow text mining method so as to realize a highly autonomous adaptive IR system. The extra bonus of a belief-based IR model is that its retrieval behavior is more predictable and explanatory. Our initial experiments show that the belief-based adaptive IR system is as effective as a classical adaptive IR system. To our best knowledge, this is the first successful implementation and evaluation of a logic-based adaptive IR model which can efficiently process large IR collections.
Locality-Based pruning methods for web search
Authors: Moura Edleno Silva de , Santos Celia Francisca dos , Araujo Bruno Dos santos de , Silva Altigran Soares da , Calado Pavel , Nascimento Mario A.
Published: April 2008

This article discusses a novel approach developed for static index pruning that takes into account the locality of occurrences of words in the text. We use this new approach to propose and experiment on simple and effective pruning methods that allow a fast construction of the pruned index. The methods proposed here are especially useful for pruning in environments where the document database changes continuously, such as large-scale web search engines. Extensive experiments are presented showing that the proposed methods can achieve high compression rates while maintaining the quality of results for the most common query types present in modern search engines, namely, conjunctive and phrase queries. In the experiments, our locality-based pruning approach allowed reducing search engine indices to 30% of their original size, with almost no reduction in precision at the top answers. Furthermore, we conclude that even an extremely simple locality-based pruning method can be competitive when compared to complex methods that do not rely on locality information.
On ranking techniques for desktop search
Authors: Cohen Sara , Domshlak Carmel , Zwerdling Naama
Published: April 2008

Users tend to store huge amounts of files, of various formats, on their personal computers. As a result, finding a specific, desired file within the file system is a challenging task. This article addresses thedesktop searchproblem by considering various techniques for ranking results of a search query over the file system. First, basic ranking techniques, which are based on various file features (e.g., file name, access date, file size, etc.), are considered and their effectiveness is empirically analyzed. Next, two learning-based ranking schemes are presented, and are shown to be significantly more effective than the basic ranking methods. Finally, a novel ranking technique, based on query selectiveness, is considered for use during the cold-start period of the system. This method is also shown to be empirically effective, even though it does not involve any learning.
Task activity vectors
Authors: Merkel Andreas , Bellosa Frank
Published: April 2008

Non-uniform utilization of functional units in combination with hardware mechanisms such as clock gating leads to different power consumptions in different parts of a processor chip. This in turn leads to non-uniform temperature distributions and problematic local hotspots, depending on the characteristics of the currently running task. The operating system's scheduler, responsible for deciding which task to run at what time, can influence temperature distribution. Our work investigates what the operating system can do to alleviate the problem of hotspots. We propose task activity vectors describing which functional units a task uses to what degree. With the knowledge provided by these vectors, the scheduler can schedule tasks using different units successively, distribute tasks using a particular unit excessively over the system's processors, or mix tasks using different units on a SMT processor. We implemented several vector-based scheduling strategies for Linux. Our evaluations show that vector-based scheduling considerably reduces hotspots.
Parallax
Authors: Meyer Dutch T. , Aggarwal Gitika , Cully Brendan , Lefebvre Geoffrey , Feeley Michael J. , Hutchinson Norman C. , Warfield Andrew
Published: April 2008

Parallax is a distributed storage system that uses virtualization to provide storage facilities specifically for virtual environments. The system employs a novel architecture in which storage features that have traditionally been implemented directly on high-end storage arrays and switches are relocated into a federation of storage VMs, sharing the same physical hosts as the VMs that they serve. This architecture retains the single administrative domain and OS agnosticism achieved by array- and switch-based approaches, while lowering the bar on hardware requirements and facilitating the development of new features. Parallax offers a comprehensive set of storage features including frequent, low-overhead snapshot of virtual disks, the 'gold-mastering' of template images, and the ability to use local disks as a persistent cache to dampen burst demand on networked storage.
Replication degree customization for high availability
Authors: Zhong Ming , Shen Kai , Seiferas Joel
Published: April 2008

Object replication is a common approach to enhance the availability of distributed data-intensive services and storage systems. Many such systems are known to have highly skewed object request probability distributions. In this paper, we propose an object replication degree customization scheme that maximizes the expected service availability under given object request probabilities, object sizes, and space constraints (e.g., memory/storage capacities). In particular, we discover that the optimal replication degree of an object should be linear in the logarithm of its popularity-to-size ratio. We also study the feasibility and effectiveness of our proposed scheme using applications driven by real-life system object request traces and machine failure traces. When the data object popularity distribution is known a priori, our proposed customization can achieve 1.32-2.92 "nines" increase in system availability (or 21-74% space savings at the same availability level) compared to uniform replication. Results also suggest that our scheme requires a moderate amount of replica creation/removal overhead (weekly changes involve no more than 0.24% objects and no more than 0.11% of total data size) under realistic object request popularity changes.
DepSpace
Authors: Bessani Alysson Neves , Alchieri Eduardo Pelison , Correia Miguel , Fraga Joni Silva
Published: April 2008

The tuple space coordination model is one of the most interesting coordination models for open distributed systems due to its space and time decoupling and its synchronization power. Several works have tried to improve the dependability of tuple spaces through the use of replication for fault tolerance and access control for security. However, many practical applications in the Internet require both fault tolerance and security. This paper describes the design and implementation of DepSpace, a Byzantine fault-tolerant coordination service that provides a tuple space abstraction. The service offered by DepSpace is secure, reliable and available as long as less than a third of service replicas are faulty. Moreover, the content-addressable confidentiality scheme developed for DepSpace bridges the gap between Byzantine fault-tolerant replication and confidentiality of replicated data and can be used in other systems that store critical data.
Hang analysis
Authors: Wang Xi , Guo Zhenyu , Liu Xuezheng , Xu Zhilei , Lin Haoxiang , Wang Xiaoge , Zhang Zheng
Published: April 2008

Soft hang is an action that was expected to respond instantly but instead drives an application into a coma. While the application usually responds eventually, users cannot issue other requests while waiting. Such hang problems are widespread in productivity tools such as desktop applications; similar issues arise in server programs as well. Hang problems arise because the software contains blocking or time-consuming operations in graphical user interface (GUI) and other time-critical call paths that should not.

This paper proposes HangWiz to find hang bugs in source code, which are difficult to eliminate before release by testing, as they often depend on a user's environment. HangWiz finds hang bugs by finding hang points: an invocation that is expected to complete quickly, such as a GUI action, but calls a blocking function. HangWiz collects hang patterns from runtime traces supplemented with expert knowledge, and feed these patterns into a static analysis framework that searches exhaustively for hang points that involve potential hang bugs.

Experiments with several large, real-world software packages (including a source control client, a graphics editor and a web server) show that there are several hang bugs in these applications, and that HangWiz is effective in finding them. The experiments also demonstrate that HangWiz is scalable and can analyze millions of lines of code. We further discuss related techniques and report our experience on fixing hang bugs.
30 seconds is not enough!
Authors: Peter Simon , Baumann Andrew , Roscoe Timothy , Barham Paul , Isaacs Rebecca
Published: April 2008

The basic system timer facilities used by applications and OS kernels for scheduling timeouts and periodic activities have remained largely unchanged for decades, while hardware architectures and application loads have changed radically. This raises concerns with CPU overhead power management and application responsiveness.

In this paper we study how kernel timers are used in the Linux and Vista kernels, and the instrumentation challenges and tradeoffs inherent in conducting such a study. We show how the same timer facilities serve at least five distinct purposes, and examine their performance characteristics under a selection of application workloads. We show that many timer parameters supplied by application and kernel programmers are somewhat arbitrary, and examine the potential benefit of adaptive timeouts.

We also discuss the further implications of our results, both for enhancements to the system timer functionality in existing kernels, and for the clean-slate design of a system timer subsystem for new OS kernels, including the extent to which applications might require such an interface at all.
Samurai
Authors: Pattabiraman Karthik , Grover Vinod , Zorn Benjamin G.
Published: April 2008

Programs written in type-unsafe languages such as C and C++ incur costly memory errors that result in corrupted data structures, program crashes, and incorrect results. We present a data-centric solution to memory corruption called critical memory, a memory model that allows programmers to identify and protect data that is critical for correct program execution. Critical memory defines operations to consistently read and update critical data, and ensures that other non-critical updates in the program will not corrupt it. We also present Samurai, a runtime system that implements critical memory in software. Samurai uses replication and forward error correction to provide probabilistic guarantees of critical memory semantics. Because Samurai does not modify memory operations on non-critical data, the majority of memory operations in programs run at full speed, and Samurai is compatible with third party libraries. Using both applications, including a Web server, and libraries (an STL list class and a memory allocator), we evaluate the performance overhead and fault tolerance that Samurai provides. We find that Samurai is a useful and practical approach for the majority of the applications and libraries considered.
Controlled, systematic, and efficient code replacement for running java programs
Authors: Nicoara Angela , Alonso Gustavo , Roscoe Timothy
Published: April 2008

In this paper we present PROSE, a system that performs reversible and systematic changes to running Java applications without requiring them to be shut down. PROSE is motivated by scenarios such as hotfixes, online program instrumentation and debugging, and evolution of critical legacy applications. In PROSE, changes to running applications are performed by replacing method bodies. To select which code to replace, PROSE supports matching based on both type information and regular expressions. New code can invoke the method it replaces, facilitating code evolution. Changes are composable, and may be reordered or selectively withdrawn at any time. Furthermore, the dynamic changes are expressed as Java classes rather than through an additional programming language. We describe the architecture of PROSE, the challenges of using aggressive inlining to achieve performance, and use standard benchmarks to demonstrate code performance comparable with, or better than, compile-time systems from the Aspect-Oriented Programming community.
Switchblade
Authors: Fetzer Christof , Süßkraut Martin
Published: April 2008

System call interposition is a common approach to restrict the power of applications and to detect code injections. It enforces a model that describes what system calls and/or what sequences thereof are permitted. However, there exist various issues like concurrency vulnerabilities and incomplete models that restrict the power of system call interposition approaches. We present a new system, SwitchBlade, that uses randomized and personalized fine-grained system call models to increase the probability of detecting code injections. However, using a fine-grain system call model, we cannot exclude the possibility that the model is violated during normal program executions. To cope with false positives, SwitchBlade uses on-demand taint analysis to update a system call model during runtime.
Eudaemon
Authors: Portokalidis Georgios , Bos Herbert
Published: April 2008

Eudaemon is a technique that aims to blur the borders between protected and unprotected applications, and brings together honeypot technology and end-user intrusion detection and prevention. Eudaemon is able to attach to any running process, and redirect execution to a user-space emulator that will dynamically instrument the binary by means of taint analysis. Any attempts to subvert control flow, or to inject malicious code will be detected and averted. When desired Eudaemon can reattach itself to the emulated process, and return execution to the native binary. Selective emulation has been investigated before as a mean to heal an attacked program or to generate a vaccine after an attack is detected, by applying intensive instrumentation to the vulnerable region of the program. Eudaemon can move an application between protected and native mode at will, e.g., when spare cycles are available, when a system policy ordains it, or when it is explicitly requested. The transition is performed transparently and in very little time, thus incurring minimal disturbance to an actively used system Systems offering constant protection against similar attacks have also been proposed, but require access to source code or explicit operating system support, and often induce significant performance penalties We believe that Eudaemon offers a flexible mechanism to detect a series of attacks in end-user systems with acceptable overhead. Moreover, we require no modification to the running system and/or installation of a hypervisor, with an eye on putting taint analysis within reach of the average user.
Flicker
Authors: McCune Jonathan M. , Parno Bryan J. , Perrig Adrian , Reiter Michael K. , Isozaki Hiroshi
Published: April 2008

We present Flicker, an infrastructure for executing security-sensitive code in complete isolation while trusting as few as 250 lines of additional code. Flicker can also provide meaningful, fine-grained attestation of the code executed (as well as its inputs and outputs) to a remote party. Flicker guarantees these properties even if the BIOS, OS and DMA-enabled devices are all malicious. Flicker leverages new commodity processors from AMD and Intel and does not require a new OS or VMM. We demonstrate a full implementation of Flicker on an AMD platform and describe our development environment for simplifying the construction of Flicker-enabled code.
On a query algorithm for a divisibility problem
Authors: Dumitrescu Adrian , Xu Guangwu
Published: April 2008

According to an old result of Turán, any (
n
+ 1)-subset of {1, 2, ..., 2
n
} contains a pair of divisible numbers. Ciurea et al. have recently considered a natural algorithmic variant of this classic mathematical result: if the subset is not known, and it is only accessible via a membership oracle, what is the minimum number of questions necessary to identify one such divisible pair? They showed a 4/3
n
--
O
(1) lower bound and also designed an algorithm which they conjectured asks no more than 4/3
n
+
O
(1) queries, and therefore would be optimal. We reanalyze the proposed algorithm and prove that it comes close to the conjectured value, in asking no more than (4/3 + 5/108)
n
+
O
(1) queries; this corrects an error in the old analysis.
Symbolic-algebraic methods for linear partial differential operators
Authors: Shemyakova Ekaterina
Published: April 2008

This thesis is devoted to the study of symbolic-algebraic factorization, classification, and integration methods for Linear Partial Differential Operators (LPDOs).
A maple library for high performance sparse polynomial arithmetic
Authors: Pearce Roman , Monagan Michael
Published: April 2008

We have developed a library for sparse polynomial arithmetic to supplement Maple's internal routines. Along the way we identified three common sources of inefficiency in existing implementations.
CoCoA
Authors: Abbott John , Bigatti Anna , Caboara Massimo , Robbiano Lorenzo
Published: April 2008

CoCoA is a
special-purpose
system for doing Computations in Commutative Algebra. It runs on all common platforms.
The complexity of fixed-parameter problems
Authors: Buss Jonathan F. , Islam Tarique M.
Published: April 2008

We describe how to found and develop the theory of fixed-parameter complexity and hardness in a manner both fully analgous to the classical theory of
NP
-completeness and much simpler than the original development. We present some recent advance made using this approach.
Computational geometry column 50
Authors: O'Rourke Joseph
Published: April 2008

Two long-open problems have been solved: (1) every sufficiently large planar point set in general position contains the vertices of an empty hexagon; (2) every finite collection of polygons of equal area have a common hinged dissection.
Future generation supercomputers I
Authors: Venkateswaran N. , Srinivasan Deepak , Manivannan Madhavan , Sai Sagar T P Ramnath , Gopalakrishnan Shyamsundar , Elangovan VinothKrishnan , Chandrasekar Karthik , Ramesh Prem Kumar , Venkatesan Viswanath , Babu Arvindakshan , Sudharshan
Published: April 2008

As a result of the increasing requirements of present and future computation intensive applications, there have been many fundamentally divergent approaches such as the Blue-Gene, TRIPS, HERO, Cascade spurred in order to provide increased performance at node level in supercomputing clusters. The design of the node architecture should be such that 'Cost-Effective Supercomputing' is realized without compromising on the requirements of the ever-performance hungry grand challenge applications. However, to increase performance at the cluster level, scalability and likewise tackling the mapping complexity across the large cluster of nodes becomes critical. The potential of such a node architecture can be fully exploited only with an appropriate cluster architecture. In an attempt to address these issues for efficient and Cost-Effective Supercomputing, we propose a novel paradigm for designing High Performance Clusters, in two papers. In paper-II, we discuss the design of operating system and cluster architecture. In this paper, we present a node architecture model based on the Memory In Processor paradigm and discuss the related architectural aspects (ISA, compiler, network interconnection etc). We provide a design space based on the proposed model for which a simulator is developed, with the help of which the performance of such a node architecture is outlined.
Introduction
Authors: Kise Kenji , Sato Toshinori , Nakajo Hironori
Published: April 2008

In this issue, we present the papers from the proceedings of the 2nd International Workshop on Advanced Low Power Systems (ALPS 2007) that was held in conjunction with the 21st International Conference on Supercomputing in Seattle.

"Thoughtfulness" is an important keyword in the both current and future technologies in all over the world: Thoughtful to human being, thoughtful to our surroundings, thoughtful to the earth, and so on. For the thoughtfulness, Low-power is believed to be one of the most indispensable keyword. The ALPS workshop focuses on the current technological challenges in developing low-power and power-aware computing systems ranging from servers to embedded devices. The goal of the workshop is to bring all aspects of power-aware computing from industry and academia.

This year, we have one invited talk entitled "An Under 2W 100GOPS Video Recognition Processor Based on a Linear Array of 128 4-Way VLIW Processing Elements" by Shorin Kyo (NEC Corporation) and 6 papers selected based on the full paper review by the program committee members.

The first set of papers discusses low-power designs. We have three papers: "Optimal Pipeline Depth with Pipeline Stage Unification Adoption" by Jun Yao, Hajime Shimada, Shinobu Miwa, and Shinji Tomita, "VCLEARIT: A VLSI CMOS Circuit Leakage Reduction Technique For Nanoscale Technologies" by Preetham Lakshmikanthan and Adrian Nunez, and "Leakage Energy Reduction in Cache Memory by Data Compression" by Kiyofumi Tanaka and Takahiro Kawahara.

The second set of papers: "Preventing Timing Errors on Register Writes: Mechanisms of Detections and Recoveries" by Hidetsugu Irie, Ken Sugimoto, Masahiro Goshima, and Suichi Sakai, "Not Multi-, but Many-Core: Designing Integral Parallel Architectures for Embedded Computation" by Mihaela Malita, Gheorghe Stefany, and Dominique Thiebaut, and "Fine-grain Compensation Method with Consideration of Trade-offs between Computation and Data Transfer for Power Consumption" by Takefumi Miyoshi and Nobuhiko Sugino, covers reliability, many-core and parallelization issues.

All papers here are going to create the way to the new aspects of low-power systems. We hope you will find the papers of this special issue of Computer Architecture News to be stimulating and that you will be inspired to contribute your efforts to the future low power systems.
Leakage energy reduction in cache memory by data compression
Authors: Tanaka Kiyofumi , Kawahara Takahiro
Published: April 2008

Cache memory is effective in bridging a growing speed gap between a processor and relatively slow external main memory. Almost all of today's commercial processors, not only high-performance microprocessors but embedded ones, have on-chip cache memories. However, energy consumption in the cache memory would approach or exceed 50% of the total consumption by the processors, which leads to a serious problem in terms of allowable temperature and performance improvement. An important point to note is that, in the near future, static (leakage) energy will dominate the energy consumption in deep sub-micron processes. In this paper, we propose cache memory architecture that exploits gated-Vdd control per cache block and a dynamic data compression scheme in the secondary cache, and achieves efficient reduction of static energy consumed by the secondary cache memory. In the simulation using SPEC95 integer benchmarks, our technique reduced about 45% of leakage energy in the cache at maximum, and about 28% on average.
Preventing timing errors on register writes
Authors: Irie Hidetsugu , Sugimoto Ken , Goshima Masahiro , Sakai Shuich
Published: April 2008

To deal with the increasing varitations of the intra-chip transisters, one promising approach is to dynamically detect and recover the timing-errors with microarchitecutre. This will induce dependability and efficiency into microprocessors because it allows VLSI to operate at the optimum frequency and voltage while ensuring accuracy.

A few approaches for dynamically detecting timing-errors have been proposed, but none of them have focused on register writes. In this paper, we propose a technique for detecting and recovering from timing errors during register writes. We introduce a verifying technique that uses additional buffer (called the write assurance buffer (WAB)) which is provided with a sufficient timing margin. The evaluation results reveal a performance degradation of 4.5% using an 8-entry WAB; this value becomes negligible when a 16-entry WAB is used.
Fine-grain compensation method with consideration of trade-offs between computation and data transfer for power consumption
Authors: Miyoshi Takefumi , Sugino Nobuhiko
Published: April 2008

Fine-grain parallelizing method with consideration of the number of data transfers for low power consumption is proposed. In the proposed method, power consumption by data transfers between processor elements in a multiprocessor is focused on, and the number of data transfers is reduced.

In this paper, a measure based on the relationship between variables in a given program is defined to evaluate the number of data transfers, firstly. And then a proposed compensation method by use of the evaluation of power consumption based on the measure is explained. Finally, the result of applying proposed compensation method implemented on COINS framework to several example programs is shown.
Internet nuggets
Authors: Thorson Mark
Published: April 2008

This column consists of selected traffic from the
comp.arch
newsgroup, a forum for discussion of computer architecture on the Internet---an international computer network.

As always, the opinions expressed in this column are the personal views of the authors, and do not necessarily represent the institutions to which they are affiliated.

Text which sets the context of a message appears underlined or in italics; this is usually text the author has quoted from earlier messages. The code-like expressions below the authors' names are their addresses on Internet.
Apical Transporters for Neutral Amino Acids: Physiology and Pathophysiology
Authors: Bröer Stefan
Published: April 2008

Absorption of amino acids in kidney and intestine involves a variety of transporters for different groups of amino acids. This is illustrated by inherited disorders of amino acid absorption, such as Hartnup disorder, cystinuria, iminoglycinuria, dicarboxylic aminoaciduria, and lysinuric protein intolerance, affecting separate groups of amino acids. Recent advances in the molecular identification of apical neutral amino acid transporters has shed a light on the molecular basis of Hartnup disorder and iminoglycinuria.
Neural Systems Controlling the Drive to Eat: Mind Versus Metabolism
Authors: Zheng Huiyuan , Berthoud Hans-Rudi
Published: April 2008

With the bleak outlook that 75% of Americans will be overweight or obese in 10 years, it is essential to find efficient help very soon. Knowledge of the powerful and complex neural systems conferring the basic drive to eat is a prerequisite for designing efficient therapies. Recent studies suggest that the cross talk between brain areas involved in cognitive, emotional, and metabolic-regulatory functions may explain why energy homeostasis breaks down for many predisposed individuals in our modern environment.
Recruitment in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial: the First Phase of Recruitment at Henry Ford Health System
Authors: Lamerato Lois E. , Marcus Pamela M. , Jacobsen Gordon , Johnson Christine Cole
Published: April 2008

Objective: Recruitment of healthy subjects to long-term randomized controlled trials (RCTs) of cancer prevention or early detection has proven to be a difficult task. To quantify recruitment yield as well as characteristics of successfully recruited participants, we examined recruitment outcomes at 1 of the 10 centers participating in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, a National Cancer Institute–funded RCT of cancer screening modalities.

Materials and Methods: During the early recruitment phase of PLCO (1993-1997), data on recruitment outcome were collected at the Henry Ford Health System (HFHS) in Detroit, Michigan. In this phase, HFHS identified potential participants using patient databases. Records were used to assess recruitment success by age, sex, race, household income (using area-based U.S. Census data), and preexisting morbidity. Logistic regression was used to assess whether enrollment success differed significantly according to these factors.

Results: Of 74,139 persons ages 55 to 74 invited by HFHS to participate, 8,250 (11%) `enrolled. In multivariate analyses, the odds of enrolling were modestly but significantly higher for women, Caucasians, persons in their 60's, and persons living in census blocks with higher median household income. Persons with two or more preexisting morbidities had significantly lower odds of enrolling compared to those with one or no preexisting morbidities.

Conclusions: These data suggest that only a small fraction of persons invited to enroll in long-term RCTs of cancer screening modalities actually do so. In this urban, Midwestern setting, certain characteristics including age, race, and income influenced recruitment success, albeit modestly. (Cancer Epidemiol Biomarkers Prev 2008;17(4):827–33)
BTF4/BTNA3.2 and GCS as Candidate mRNA Prognostic Markers in Epithelial Ovarian Cancer
Authors: Le Page Cécile , Ouellet Véronique , Quinn Michael C.J. , Tonin Patricia N. , Provencher Diane M. , Mes-Masson Anne-Marie
Published: April 2008

This study aims to identify reliable prognosis markers to predict patient outcome at surgery in high-grade serous epithelial ovarian cancer by a real-time quantitative PCR (RT-q-PCR)-based test. Seventeen tissue samples from serous epithelial ovarian cancer patients were screened by DNA microarray to identify genes differentially expressed between tumors from patients who relapsed within 18 months and tumors from patients showing no relapse or relapsed after 24 months after initial diagnosis. RNA expression of a subset of genes was validated by RT-q-PCR in the initial set of 17 samples. From these results, a refined list was selected and tested in independent samples from 41 serous. Expression was associated with time to relapse and clinical variables. Microarray analysis identified a profile of 34 differentially expressed genes. RT-q-PCR validated the expression profile of a subset of seven genes in the initial set of patients. Differential gene expression was also validated in an independent set of patients. Low BTF4 or GCS expression was strongly associated with poor outcome in Kaplan-Meier analysis (P < 0.05, log-rank test) and Cox univariate as well as in multivariate analyses with a higher hazard ratio than clinical variables, such as residual disease, age, stage, and grade. (Cancer Epidemiol Biomarkers Prev 2008;17(4):913–20)
Serum Levels of Vitamin D Metabolites and Breast Cancer Risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial
Authors: Freedman D. Michal , Chang Shih-Chen , Falk Roni T. , Purdue Mark P. , Huang Wen-Yi , McCarty Catherine A. , Hollis Bruce W. , Graubard Barry I. , Berg Christine D. , Ziegler Regina G.
Published: April 2008

Experimental and epidemiologic studies suggest that vitamin D metabolites (1,25-dihydroxyvitamin D [1,25(OH)2D] and its precursor 25-hydroxyvitamin D [25(OH)D]) may reduce breast cancer risk. We examined subsequent breast cancer risk related to serum levels of these metabolites. In a cohort of women ages 55 to 74 years, who donated blood at baseline (1993-2001) in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we identified 1,005 incident breast cancer cases during follow-up through 2005 (mean time between blood draw and diagnosis, 3.9 years). Noncases (n = 1,005) were frequency matched to the cases based on age and year of entry. Sample weights that accounted for unequal probabilities of selecting cases and noncases were applied to make inferences that reflected the entire Prostate, Lung, Colorectal, and Ovarian cohort. Using Cox proportional hazards modeling, we computed breast cancer relative risks (RR) and 95% confidence intervals (95% CI) by quintile for each metabolite. The RR of breast cancer for the highest quintile of 25(OH)D concentration versus the lowest was 1.04 (95% CI, 0.75-1.45; Ptrend = 0.81). Similarly, the breast cancer RR for the highest quintile of 1,25(OH)2D compared with the lowest was 1.23 (95% CI, 0.91-1.68; Ptrend = 0.14). Excluding the first 2 years of follow-up did not materially alter these estimates. There was also no evidence of inverse risk in older women (≥60 years) versus younger women (<60 years). In this prospective study of postmenopausal women, we did not observe an inverse association between circulating 25(OH)D or 1,25(OH)2D and breast cancer risk, although we cannot exclude an association in younger women or with long-term or earlier exposure. (Cancer Epidemiol Biomarkers Prev 2008;17(4):889–94)
Dairy Product, Saturated Fatty Acid, and Calcium Intake and Prostate Cancer in a Prospective Cohort of Japanese Men
Authors: Kurahashi Norie , Inoue Manami , Iwasaki Motoki , Sasazuki Shizuka , Tsugane and Shoichiro ,   for the Japan Public Health Center–Based Prospective Study Group
Published: April 2008

Many epidemiologic studies have reported a positive association between dairy products and prostate cancer. Calcium or saturated fatty acid in dairy products has been suspected as the causative agent. To investigate the association between dairy products, calcium, and saturated fatty acid and prostate cancer in Japan, where both the intake of these items and the incidence of prostate cancer are low, we conducted a population-based prospective study in 43,435 Japanese men ages 45 to 74 years. Participants responded to a validated questionnaire that included 138 food items. During 7.5 years of follow-up, 329 men were newly diagnosed with prostate cancer. Dairy products were associated with a dose-dependent increase in the risk of prostate cancer. The relative risks (95% confidence intervals) comparing the highest with the lowest quartiles of total dairy products, milk, and yogurt were 1.63 (1.14-2.32), 1.53 (1.07-2.19), and 1.52 (1.10-2.12), respectively. A statistically significant increase in risk was observed for both calcium and saturated fatty acid, but the associations for these were attenuated after controlling for potential confounding factors. Some specific saturated fatty acids increased the risk of prostate cancer in a dose-dependent manner. Relative risks (95% confidence intervals) on comparison of the highest with the lowest quartiles of myristic acid and palmitic acid were 1.62 (1.15-2.29) and 1.53 (1.07-2.20), respectively. In conclusion, our results suggest that the intake of dairy products may be associated with an increased risk of prostate cancer. (Cancer Epidemiol Biomarkers Prev 2008;17(4):930–7)
Health Insurance–Related Disparities in Colorectal Cancer Screening in Virginia
Authors: de Bosset Vanessa , Atashili Julius , Miller William , Pignone Michael
Published: April 2008

Background: Colorectal cancer (CRC) screening rates remain low in the United States. The effect of health insurance on CRC screening is not clear. We assessed the association between having health insurance and being screened for CRC and the factors that modify this association.

Methods: We used data from the 2005 Virginia Behavioral Risk Factor Surveillance System to evaluate the association of self-reported insurance coverage on self-reported CRC screening among all men and women ages ≥50 years (N = 2,887). Prevalence odds ratios (POR) were estimated using unconditional logistic regression. All covariates were assessed for potential effect measure modification and confounding. All analyses accounted for the Behavioral Risk Factor Surveillance System complex survey sampling design.

Results: Overall, participants who reported having insurance coverage were more than twice as likely to report being screened for CRC compared with those who reported having none [crude POR, 2.16; 95% confidence interval (95% CI), 1.26-3.68]. This relationship differed between men and women (PORmales, 3.37; 95% CI, 1.63-6.96; PORfemales, 1.46; 95% CI, 0.74-2.89). After adjusting for age and income, self-reported insurance coverage had a positive association with report of being screened among men (POR, 2.02; 95% CI, 0.96-4.23) but not among women (POR, 0.81; 95% CI, 0.34-1.93).

Conclusions: Men who reported having health insurance were more likely to report having CRC screening than those who reported not having insurance coverage. However, this effect was not observed in women. These findings, if confirmed in other study populations, indicate that improving CRC screening coverage may require not only insurance status specifications but also gender-explicit considerations. (Cancer Epidemiol Biomarkers Prev 2008;17(4):834–7)
Polymorphisms in Angiogenesis-Related Genes and Prostate Cancer
Authors: Jacobs Eric J. , Hsing Ann W. , Bain Elizabeth B. , Stevens Victoria L. , Wang Yiting , Chen Jinbo , Chanock Stephen J. , Zheng S. Lilly , Xu Jianfeng , Thun Michael J. , Calle Eugenia E. , Rodriguez Carmen
Published: April 2008

Background: Angiogenesis is required for development and progression of prostate cancer. Potentially functional single nucleotide polymorphisms (SNP) in genes important in prostate angiogenesis (VEGF, HIF1A, and NOS3) have previously been associated with risk or severity of prostate cancer.

Methods: Prostate cancer cases (n = 1,425) and controls (n = 1,453) were selected from the Cancer Prevention Study II Nutrition Cohort. We examined associations between 58 SNPs in nine angiogenesis-related candidate genes (EGF, LTA, HIF1A, HIF1AN, MMP2, MMP9, NOS2A, NOS3, VEGF) and risk of overall and advanced prostate cancer. Unconditional logistic regression was used to estimate odds ratios, adjusted for matching factors.

Results: Our results did not replicate previously observed associations with SNPs in VEGF, HIF1A, or NOS3, nor did we observe associations with SNPs in EGF, LTA, HIF1AN, MMP9, or NOS2A. In the MMP2 gene, three intronic SNPs, all in linkage disequilibrium, were associated with overall and advanced prostate cancer (for overall prostate cancer, Ptrend = 0.01 for rs1477017, Ptrend = 0.01 for rs17301608, Ptrend = 0.02 for rs11639960). However, two of these SNPs (rs17301608 and rs11639960) were examined and were not associated with prostate cancer in a recent genome-wide association study using prostate cancer cases and controls from the Prostate, Lung, Colorectal, and Ovary study cohort. Furthermore, when we pooled our results for these two SNPs with those from the Prostate, Lung, Colorectal, and Ovary cohort; neither SNP was associated with prostate cancer.

Conclusion: None of the SNPs examined seem likely to be importantly associated with risk of overall or advanced prostate cancer. (Cancer Epidemiol Biomarkers Prev 2008;17(4):972–7)
Risk Factors for Hepatocellular Carcinoma in a Japanese Population: A Nested Case-Control Study
Authors: Ohishi Waka , Fujiwara Saeko , Cologne John B. , Suzuki Gen , Akahoshi Masazumi , Nishi Nobuo , Takahashi Ikuno , Chayama Kazuaki
Published: April 2008

Background: Epidemiologic studies have shown effects of lifestyle-related factors on risk for hepatocellular carcinoma. However, few cohort studies have incorporated, in a strict and in-depth manner, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections or investigated synergism between such factors.

Methods: We conducted a nested case-control study using sera stored before hepatocellular carcinoma diagnosis in the longitudinal cohort of atomic bomb survivors. The study included 224 hepatocellular carcinoma cases and 644 controls that were matched to the cases on gender, age, city, time of serum storage, and method of serum storage, and countermatched on radiation dose.

Results: Univariate analysis showed that HBV and HCV infections, alcohol consumption, smoking habit, body mass index (BMI), and diabetes mellitus were associated with increased hepatocellular carcinoma risk, whereas coffee drinking was associated with decreased hepatocellular carcinoma risk. Multivariate relative risks of hepatocellular carcinoma (95% confidence interval) were 45.8 (15.2-138), 101 (38.7-263), 70.7 (8.3-601), 4.36 (1.48-13.0), and 4.57 (1.85-11.3), for HBV infection alone, HCV infection alone, both HBV and HCV infections, alcohol consumption of ≥40 g of ethanol per day, and BMI of >25.0 kg/m2 10 years before diagnosis, respectively. HBV and HCV infection and BMI of >25.0 kg/m2 remained independent risk factors even after adjusting for severity of liver fibrosis. Among HCV-infected individuals, the relative risk of hepatocellular carcinoma for a 1 kg/m2 increase in BMI was 1.39 (P = 0.003).

Conclusions: To limit the risk for hepatocellular carcinoma, control of excess weight may be crucial for individuals with chronic liver disease, especially those with chronic hepatitis C. (Cancer Epidemiol Biomarkers Prev 2008;17(4):846–54)
Reliability and Validity of a Questionnaire to Measure Colorectal Cancer Screening Behaviors: Does Mode of Survey Administration Matter?
Authors: Vernon Sally W. , Tiro Jasmin A. , Vojvodic Rachel W. , Coan Sharon , Diamond Pamela M. , Greisinger Anthony , Fernandez Maria E.
Published: April 2008

Valid and reliable self-report measures of cancer screening behaviors are important for evaluating efforts to improve adherence to guidelines. We evaluated test-retest reliability and validity of self-report of the fecal occult blood test (FOBT), sigmoidoscopy (SIG), colonoscopy (COL), and barium enema (BE) using the National Cancer Institute colorectal cancer screening (CRCS) questionnaire. A secondary objective was to evaluate reliability and validity by mail, telephone, and face-to-face survey administration modes. Consenting men and women, 51 to 74 years old, receiving care at a multispecialty clinic for at least 5 years who had not been diagnosed with colorectal cancer were stratified by prior CRCS status and randomized to survey mode (n = 857). Within survey mode, respondents were randomized to complete a second survey at 2 weeks, 3 months, or 6 months. Comparing self-report with administrative and medical records, concordance estimates were 0.91 for COL, 0.85 for FOBT, 0.85 for SIG, and 0.92 for BE. Overall sensitivity estimates were 0.91 for COL, 0.82 for FOBT, 0.76 for SIG, and 0.56 for BE. Specificity estimates were 0.91 for COL, 0.86 for FOBT, 0.89 for SIG, and 0.97 for BE. Sensitivity and specificity varied little by survey mode for any test. Report-to-records ratio showed overreporting for SIG (1.1), COL (1.15), and FOBT (1.57), and underreporting for BE (0.82). Reliability at all time intervals was highest for COL; there was no consistent pattern according to survey mode. This study provides evidence to support the use of the National Cancer Institute CRCS questionnaire to assess self-report with any of the three survey modes. (Cancer Epidemiol Biomarkers Prev 2008;17(4):758–67)