bluuebunny/crossref_metadata_2025 huggingface dataset:
Need to consider variations within demographic groups when evaluating educational interventions
Authors: Kumar Amruth N.
Published: August 2009

Traditionally, educational interventions in Computer Science have been studied for their effect on entire classes, or specific demographic groups. But, in our studies, we have found that often, significant interactions exist among demographic groups. Treating demographic groups as homogeneous groups when evaluating educational interventions in Computer Science could miss subtle interactions among the groups.
Computer science student transformations
Authors: Moström Jan Erik , Boustedt Jonas , Eckerdal Anna , McCartney Robert , Sanders Kate , Thomas Lynda , Zander Carol
Published: August 2009

We examine the transformations experienced by students during their study of computing. These transformations led to changes in the students' perceptions of computer science, in their sense of identity as computer scientists, their behavior and their confidence. The changes are caused by learning or using particular concepts, and often associated with writing computer programs, learning new programming languages, or interacting with peers.
Virtual machines
Authors: Schocken Shimon
Published: August 2009

Various forms of virtualization play key roles in the construction and usage of diverse system artifacts ranging from modern compilers to hardware migration to mobile computing. Virtualization is also a powerful concept on cognitive grounds, requiring considerable abstraction skills and modeling abilities. We present a methodology, a software tool, and a set of instructional resources designed to expose students to virtual machines, focusing on both abstraction and implementation issues. An early version of our methodology appeared in a book form [4] in which we describe how to build a complete computer system - hardware and software - in one semester. Recently we've re-written our VM emulation software and consolidated all our VM materials into a web site that supports a stand-alone module on virtual machines [5]. This module can be plugged into many system-oriented CS courses. All the resources that we present are freely available in open source and are presently used successfully in several universities.
Learning styles
Authors: Zander Carol , Thomas Lynda , Simon Beth , Murphy Laurie , McCauley Renée , Hanks Brian , Fitzgerald Sue
Published: August 2009

We present what students say about their preferred learning style to succeed in introductory programming. Using the Felder-Silverman learning styles, students contrasted the 'best' learning style for programming with the 'best' for learning mathematics. Overall students believe that while they learn mathematics using a reflective style, learning to program is significantly more active. They also believe learning mathematics has a strong verbal component, whereas learning programming is primarily visual.
Why are we still here?
Authors: Dee Hannah M. , Petrie Karen E. , Boyle Roger D. , Pau Reena
Published: August 2009

This paper describes a study into the attitudes and experiences of women at three distinct stages of the career pipeline: undergraduate, graduate student, and staff. Computing has often been likened to a "leaky pipeline" for women, so this work aims to consider various aspects of the student experience from the perspective of those who have in some sense
succeeded
and got at least as far as studying the subject at degree level. Through concentrating on the opinions and experiences of women who have persisted (and in some sense, done well) in computing, the authors hope to accentuate the positive: rather than work out what makes women drop out of computing, we instead consider what makes them stay.
Exploring technologies for building collaborative learning communities among diverse student populations
Authors: Anderson Nicole , Lin Chi-Cheng
Published: August 2009

Collaborative learning has long been recognized as an effective approach to enhance the learning process. The purpose of this research was to investigate mechanisms for building an inclusive collaborative learning community outside the classroom that connects students with diverse backgrounds and ultimately enhances students' learning experience. To accomplish this, we conducted a study using blogs and user groups to support virtual collaborative communities in our upper division computer science courses. Our results show that blogs are an effective tool for bringing together these diverse student groups to create an inclusive learning environment.
A unified approach to introductory computer science
Authors: Huang Timothy , Briggs Amy
Published: August 2009

We discuss our recent experience offering a single introductory computer science course for all students with no prior computer science coursework. The new course interleaves material from traditional CS0 and CS1 courses, providing all students with both a broad overview and an appreciation for the algorithmic foundations of the discipline of computer science. We describe our motivation for this approach, the content of the new course, and some conclusions based on our experiences and feedback from student course evaluations.
Teaching design patterns using a family of games
Authors: Gómez-Martín Marco Antonio , Jiménez-Díaz Guillermo , Arroyo Javier
Published: August 2009

Object-oriented software design requires a combination of abilities that can not be easily transferred to the students in lecture sessions. Based on our experience, this paper details how to increase student comprehension of design patterns through a project-based approach that consists in the development of a family of abstract strategy games in an incremental way. In this approach, the application resulting from the previous assignment is refined using refactoring and design patterns to complete the next assignment. Our approach is illustrated by the development of a family of n-in-a-row games in a CS3 course.
Evaluation of a software engineering course by reflection
Authors: Barzilay Ohad , Hazzan Orit , Yehudai Amiram
Published: August 2009

The evaluation of an advanced software engineering (SE) course is a challenging task that should be addressed as part of the course design. In this paper, we describe an implementation of the reflective practitioner perspective as part of an advanced SE course and introduce its use for feedback purposes. Reflective feedback goes beyond merely using feedback questionnaires. Furthermore, we show, using both qualitative and quantitative empirical data, that the course on which the perspective was applied meets its objectives and fosters students' awareness to the multidimensional nature of SE.
Computer science issues in high school
Authors: Gal-Ezer Judith , Shahak Daphna , Zur Ela
Published: August 2009

Computer Science (CS) seems to be one of the few remaining disciplines almost entirely dominated by men, especially among university faculty and in the hi-tech industry. This phenomenon is prevalent throughout the western world. In Israel, we observed it in high schools where only 30% of the students who choose to major in CS are women. It continues in Israeli universities and colleges, where usually less than 30% of CS students are women. In this paper, we provide data describing the situation in Israeli high schools. In addition, we present a survey conducted among high school students which aimed, among other goals, to discover why girls did not choose to take CS in high school. We analyze the data and provide some conclusions and ways to deal with this situation.
First experiences with a classroom recording system
Authors: Dickson Paul E. , Adrion W. Richards , Hanson Allen R. , Arbour David T.
Published: August 2009

This paper describes our experiences with the first partial deployment of Presentations Automatically Organized from Lectures (PAOL), a lecture recording system developed and tested at the University of Massachusetts Amherst. PAOL automatically records all information presented during lectures using any combination of computer, whiteboard, and overhead presentation and compiles the captured lectures into indexed presentations. We discuss lessons learned from this deployment that have application in lecture recording specifically and classroom technology in general. We also discuss our initial evaluation of created presentations as determined by a small focus group study.
Estimating programming knowledge with Bayesian knowledge tracing
Authors: Kasurinen Jussi , Nikula Uolevi
Published: August 2009

In this paper we present a concept for three-phase measuring method, which can be used to obtain data on student learning. The focus of this method lies on the technical aspects of learning programming, answering questions like which programming constructs students applied and how large portion of the students understood the concepts of programming language.

The model is based on three consecutive measurements, which are used to observe the student errors, applied programming structures and an application of a Bayesian learning model to determine the programming knowledge. So far the model has produced results which confirm prior knowledge on student learning, indicating that the concept is feasible for further development. Despite of the early development phase of the method, it offers a straightforward way for teacher to assess the course contents and student performance.
WriteOn1.0
Authors: Chandrasekar Samantha , Tront Joseph G. , Prey Jane C.
Published: August 2009

A Tablet PC combines all the features of a regular laptop computer with a digitizing screen that interacts with a complementary electronic pen stylus. The ability to annotate on a lecture presentation using the pen stylus of the Tablet PC has attracted the attention of academics to use them as a potential tool for effective classroom instruction. Tablet PC based educational software like Classroom Presenter allows the instructor to supplement lecture material comprising of static text-based PowerPoint® slides by directly annotating on them. However, computer science and engineering classes often involve the use of non text-based lecture material like a simulation demo over which a lecturer would like to make annotations. In order to facilitate this, we present a Tablet PC-based educational tool called WriteOn1.0, the second core implementation of the WriteOn tool, developed at Virginia Tech. WriteOn allows the instructor to utilize electronic ink to annotate on top of any application window visible on the Tablet PC screen, including those that play active content like a movie or simulation, by activating its virtual transparency surface called the eVellum (electronic vellum).The ability of WriteOn to improve classroom presentation were pedagogically very useful as shown by initial classroom testing. However, in order to deploy WriteOn on large scale in classrooms as an active and effective teaching tool of choice, some aspects of the application like its operational CPU performance and the GUI called for improvement. WriteOn1.0 addresses the drawbacks of WriteOn with the introduction of features such as the dynamic eVellum, a picture-based GUI and an improvement to the operational CPU performance of the screen capture process. In this paper, we shall present how WriteOn1.0 can potentially aid in effective lecturing, especially for subject matter like programming and digital circuit design, both of which involve the use of dynamic presentation material.
A visualisation tool for the programming process
Authors: Boisvert Charles R.
Published: August 2009

eL-CID (e-Learning to Communicate Iterative Development) demonstrates computer programs' iterative design using computer animation. It translates descriptions of iterative editing into a dynamic visualisation of the changes, as if code was being edited in front of the user. A range of animations has been developed and the system evaluated through action research. The evaluation shows that it is particulary useful as a reflective tool, revealing the problem solving inherent to development.
A visual proof of amortised-linear resizable arrays
Authors: Blaheta Don
Published: August 2009

We demonstrate visually why doubling capacity is the better strategy when resizing arrays. The visual proof makes simple amortised analysis more accessible to a CS2 audience.
VAST
Authors: Almeida-Martínez Francisco J. , Urquiza-Fuentes Jaime , Velázquez-Iturbide J. Ángel
Published: August 2009

In this demonstration we present VAST, a visualization tool to support teaching language processors. On the one hand, VAST provides an API that allows generating visualizations of syntax trees independently of the parser generator. On the other hand, VAST provides a GUI with multiple views: the source code, the stack and the syntax tree.
Cooperative learning to support the lacks of PBL
Authors: Garcia Martin Javier
Published: August 2009

In this paper, we describe the use of some cooperative learning methodology sessions in a Project Based Learning course, in order to cover those topics uncovered by the project.
Progressive assignment in CS1
Authors: Djordjević Mirela
Published: August 2009

This paper proposes a simple graphics programming project, Java Target project that follows the Spiral Model of teaching three different components of the introductory programming course: fundamentals, object-oriented, and event-driven programming. Especially important in this project is the progressive nature that introduces one concept and reviews others. The project consists of following progressive tasks: draw a circle (target); user defines radius, and center of a circle; report number of shots; randomize shots; select color, select shape, resize target; define user class Circle (Target); define number of circles in target; keep scores and find the best score.
Two novel prolog assignments
Authors: Mohr Jonathan
Published: August 2009

This paper describes two simple but novel Prolog assignments. The first extends the family tree example featured in many Prolog textbooks to the problem of tracing the line of succession to the throne of the British royal family. The solution uses a first-child/next-sibling representation of the royal family tree, since the birth order of a royal's children is significant when determining the order of succession. The second is a simple game that combines features of chess and rock-paper-scissors. The game board is a directed graph, rather than a simple grid.
Automatically identifying learners' problem solving strategies in-process solving algorithmic problems
Authors: Kiesmueller Ulrich , Brinda Torsten
Published: August 2009

Learners often use learning and programming environments to practice basics of programming and solving algorithmic problems. To adapt the software feedback to each learner's problem solving process, the learning environment will be enhanced with a tool to identify the individual problem solving strategy in-process automatically. Former attribution of problem solving strategies to patterns in recorded learner-system interactions by human researchers should be validated with the help of questionnaires based on the Theory of Reasoned Action. To identify the patterns automatically, speech recognition methods can be used. In this research project each single problem solving strategy is modelled by a hidden markov model.
Ensemble
Authors: Lillian (Boots) Cassel , Gregory Hislop , Nadella Bharath
Published: August 2009

Ensemble is a new NSF NSDL Pathways project working to establish a distributed digital library for computing education. This project is funded by the National Science Foundation. The project includes the CSTA portal for teaching materials for teachers in schools.
AARTIC
Authors: Mhiri Faten , Ratté Sylvie
Published: August 2009

The project's main objective is the design and development of an intelligent environment for human learning (EIAH). Our system is adaptive and intelligent and aims to guide students in the realization of their labs and to collaborate with peers. A pedagogical agent, integrated into the environment, incorporates functions of observations and personalized tutoring for learning. The system is currently tested in an introductory course in IA given to undergraduate students at ETS.
Working across time zones in cross-cultural student teams
Authors: Altin Rukiye , Bektik Mustafa , Eksioglu Nuray , Koray Can , Oner Omer Canbek , Sadetas Merve , Sener Hilal , Simsek Duygu , Ma Ching-Chen , Price Christine , Routh Christopher
Published: August 2009

The ability to collaborate with fellow workers from different cultures on international projects is a key asset in today's job market . International projects add new dimensions to student teamwork. These types of projects give students the opportunity to participate in collaboration that is remote, cross-cultural, and linguistically challenging. This proposal examines an international term project completed by the computing students of Rose-Hulman Institute of Technology and Bilkent University.
Use of intuitive tools to enhance student learning and user experience
Authors: Altin Rukiye , Bektik Mustafà , Ekşioğlu Nuray , Koray Can , Öner Ömer Canbek , Sadeta_ Merve , Şener Hilal , Simsek Duygu , Ma Ching-Chen , Price Christine , Routh Christopher R.
Published: August 2009

Most user interfaces today present system functions by use of verbal or iconic symbols on static 2D menu pages organized in a hierarchical system [1]. This is unnatural to all human beings and must be learned, thus being a barrier between the full use and understanding of computer systems. With this problem in mind we set out to build a website and collaborative application for International Children's Center (ICC) which could be used not only across languages but across ages as well. This effort was tested on a daily basis by a multinational team consisting of students from the United States and Turkey as well as children from the respective countries. This attention to usability will not only lead to an intuitive tool for the client but also teach the students in the course how to build intuitive user interfaces.
Graduate attributes and performance measures
Authors: Impagliazzo John
Published: August 2009

In this poster, the author provides a pictorial demonstration of the elements associated with assessment and its relationship to the newly developed requirements by accrediting bodies in various countries. Specifically, it illustrates expected attributes of program graduates and it highlights the importance of performance measures when assessing learning outcomes of a program. The poster shows forms of assessment and it provides definitions and examples of program mission, goals, and learning outcomes, performance indicators, performance measures, and the use of rubrics. The poster highlights the interaction of all these assessment characteristics.
Learning method based on collaborative assessment performed by the students
Authors: Mora Mora Higinio , Signes Pont María Teresa , Camps Jordá Rafael , García Chamizo Juan Manuel
Published: August 2009

This paper describes a novel method of assessment, which is being tested in the subject "Basic Computer Science". This subject is given in the fist year of the Computer Science and Engineering course, at the University of Alicante. This method consists in including the students in the assessment process of their own work, through crossed reviews where the students identify possible improvements in their classmate's work that can be performed in the successive deliveries of the same work.
Developing classification criteria for programming tasks
Authors: Skupas Bronius , Dagiene Valentina , Revilla Miguel
Published: August 2009

The Online Judge (http://icpcres.ecs.baylor.edu) is an on-line programming trainer created by University of Valladolid in 1995 with the aim of training users who participate in programming competitions. Currently this tool has over 64,000 users from many countries and more than 2,000 tasks.

In 2007 the project "Integrating On-line Judge into effective e-learning", funded by the European Commission under the Life Long Learning Programme (grant number 135221-LLP-1-2007-1-ES-KA3-KA3MP), was launched in order to satisfy the users' demand for greater pedagogic character and to facilitate the use of the Online Judge in courses of informatics in higher and secondary education.

The Online Judge has been maintaining a task database, which can be very useful for teaching algorithms at various levels. However it is not easy for teachers to find proper tasks which fit particular students. At the moment it is possible to weight task difficulty by the percentage of participants who provide correct solutions. It is impossible to find which topics or algorithms are required to solve tasks.

An attempt to classify the existing tasks by possible solution algorithms was started by the Online Judge members,

using a Wiki (http://www.algorithmist.com/index.php/Categories). However the process is ad hoc and needs systematic revision and analysis.

We are providing several schemas for classification of the tasks: (1) Categories proposed by task authors, e.g. by providing comments on the best solution. (2) Categories proposed by the Online Judge administrators, e.g. length of source code or time required for solving the task. This type of classification can only be done by the administrators as other users do not have any access to the solutions and statistical data. (3) Categories proposed by participants ranking the difficulty of solved tasks. (4) Categories proposed by teachers who have used the tasks for several years in their courses, e.g. task topics and difficulty.

To make an easier classification process we propose to develop a set of keywords or key phrases. Applying these key phrases to each task will provide more information to users.

Initial set of keywords and key phrases can include: (1) Theory or algorithms [1] needed to solve the task (Fig. 1). Fig. 1. Number of Online Judge tasks classified by algorithms (2) Task difficulty, e.g. involves required knowledge, no mathematics, basic mathematics, no algorithms, no data structures, no abstract data structures, suitable for first year students, correct algorithm is not obvious, & (3) Recommending prior tasks that should be solved first. (4) Task type by solution output format, e.g. output is unambiguous, output is ambiguous, output is one number, & (5) Task type by source, e.g. Which competition or course proposed this task? Who is the author?
Revised associate-level curricular guidelines in computer science
Authors: Hawthorne Elizabeth K. , Klee Karl J. , Campbell Robert D. , Wright Anita M.
Published: August 2009

This poster presentation features revised associate-level transfer curriculum guidelines in computer science that were recently updated by the Two-Year College Education Committee (TYCEC). These guidelines will be available online in a Web 2.0 format. As a standing committee of the ACM Education Board, the TYCEC has been for two decades developing curricular guidelines for associate-degree computing programs worldwide.
Rubyric
Authors: Auvinen Tapio , Karavirta Ville , Ahoniemi Tuukka
Published: August 2009

Writing feedback can be very time-consuming on large Computer Science courses. Evolving from years of research on computer-assisted grading tools, we present the Rubyric assessment tool which allows graders to effortlessly construct feedback with reusable phrases. The tool can be used to facilitate the manual assessment of assignments varying from essays to programming projects.
Blended learning for teaching operating systems with Windows
Authors: Hwang Seung-won
Published: August 2009

Since the release of Windows teaching materials, many experience reports have been published on OS course offerings adopting Windows kernel for course projects. Such projects, inherently requiring active learning, are reported to have both positive and negative correlations for student learning performance and responses. In this paper, we study how to maximize the traditional benefits of active learning, such as promoting student motivation, while minimizing the negatives, such as students feeling lost and overwhelmed. More specifically, we propose to blend active learning projects with closed problem sets and report student responses and learning performances.
CPATH
Authors: Cassel Lillian N. , Way Thomas , Potluri Sridhara
Published: August 2009

This project tries to provide a clarified and comprehensive understanding of the computing disciplines that allows shared experiences and expertise within and across the community. This collective sharing enables computing faculty to collaborate with other disciplines that use computing to enhance groups, and to create new cross-disciplinary areas of study and research. This involves the integration of computing with other disciplines like engineering, sciences, business, and arts and explores the challenge by bringing together instructors and researchers across the disciplinary boundaries. Distributed Expertise enhances teaching and learning experiences for students of computing and other disciplines in which computational thinking and computing models contribute to a variety of applications. This project is a collaboration by Villanova University, Virginia Technology University, and The College of New Jersey (TCNJ).
WAPPEN
Authors: Kagawa Koji
Published: August 2009

This poster presents an Eclipse RCP-based application framework named Wappen for learning programming, and especially, its plugin for Bison and Flex. In courses such as compiler construction and programming languages, learners have to use multiple languages. Time and e ort spent by learners on installation and configuration of programming environments are not negligible. Wappen provides an infrastructure on which teachers can arrange simple Web-based programming environments for various programming languages by writing plug-ins. Wappen for Oolong has been successfully used in our compiler construction lab, where Oolong is an assembly language for the Java Virtual Machine. This poster introduces Wappen for Bison/Flex that tries to help learners avoid pitfalls of Bison/Flex in some respects. It is planned to be put into practical use in our compiler construction lab this year.
Tail recursion by using function generalization
Authors: Rubio-Sánchez Manuel , Velázquez-Iturbide J. Ángel
Published: August 2009

The design of tail recursive algorithms may require thinking about iteration rather than recursion. This paper provides a methodology for deriving tail recursive functions that is based on declarative programming and the concept of function generalization, which allow to avoid iterative thinking.
A system for integral efficiency analysis of sustainable technologies
Authors: Rößling Guido , Kolarov Yavor
Published: August 2009

Sustainability is receiving increasing interest from the CS community and average users. We present plans for a system that provides an integral efficiency analysis for recommending the most appropriate sustainable technology for a given location.
How do robots foster the learning of basic concepts in informatics?
Authors: Wiesner Bernhard , Brinda Torsten
Published: August 2009

In the poster a project is presented that investigates the efficiency of using educational robots in early secondary computer science education. Results will be obtained from a comparative study in 9th grade informatics classes.
Papillary Ependymoma WHO Grade II of the Aqueduct Treated by Endoscopic Tumor Resection
Authors: Stark Andreas M. , Hugo Heinz-Herrmann , Nabavi Arya , Mehdorn H. Maximilian
Published: August 2009

Papillary ependymoma is a rare tumor that may be located along the ventricular walls or within the spinal cord. We report the case of a 54-year-old patient with a papillary ependymoma WHO grade II arising at the entrance of the aqueduct. The tumor caused hydrocephalus. The tumor was completely removed via a right-sided endoscopic approach with restoration of the aqueduct. The free cerebrospinal fluid passage through the aqueduct was not only visualized by endoscopy but also controlled by intraoperative high-field magnetic resonance imaging. Therefore, an additional endoscopic third ventriculostomy was unneccessary.
Phadiatop Infant in the Diagnosis of Atopy in Children with Allergy-Like Symptoms
Authors: Halvorsen Ragnhild , Jenner Åsa , Hagelin Else Marie , Borres Magnus P.
Published: August 2009

Background and Objective. Allergy-like symptoms such as wheezing and eczema are common in young children and an early diagnosis is important to initiate correct management. The objective of this study was to evaluate the diagnostic performance of Phadiatop Infant, an in vitro test for determination of early sensitisation to food and inhalant allergens.Patients and Methods. The study was conducted, retrospectively, using frozen sera from 122 children (median age 2.7 years) admitted to the hospital with suspected allergic symptoms. The doctor's diagnosis atopic/nonatopic was based on routinely used procedures such as clinical evaluation, SPT, total and allergen-specific IgE antibodies. The performance of Phadiatop Infant was evaluated in a blinded manner against this diagnosis.Results. Eighty-four of the 86 children classified as atopic showed a positive Phadiatop Infant test. Thirty-six were classified as nonatopic, 32 of who had a negative test. With a prevalence of atopy of 70% in this population, this gives a sensitivity of 98%, a specificity of 89%, and a positive and negative predictive value of 95% and 94%, respectively.Conclusion. The results from the present study suggest that Phadiatop Infant could be recommended as a complement to the clinical information in the differential diagnosis on IgE-mediated disease in young children with allergy-like symptoms.
Copolymers Formation by Photopolymerization of (Meth)acrylates Containing Dissolved Polyheteroarylenes
Authors: Sapozhnikov Dmitriy A. , Volkova Tat'yana V. , Sakharova Antonina A. , Gasanov Rashid G. , Voytekunas Vanda Yu. , Abadie Marc J. M. , Sanchez Jean-Yves , Vygodskii Yakov S.
Published: August 2009

Radical photopolymerization of (meth)acrylates in the presence of dissolved polyheteroarylenes has been investigated. The kinetics of radical polymerization of unsaturated monomers in the presence of polyheteroarylenes and model compounds has been studied by Differential Scanning Photocalorimetry and Infrared Spectroscopy. From the results of investigations into the kinetics and the polymer structures (Fourier Transform Infrared Spectroscopy, Nuclear Magnetic Resonance, Size-exclusion Chromatography, Thermogravimetric analysis), it has been established that radical photopolymerization of vinyl monomers in the presence of polyheteroarylenes leads to the formation of copolymers owing to chain transfer reactions and/or chain termination by the relevant condensation polymer. Using Electron Spin Resonance Spectroscopy the novel radicals upon the addition of model compounds for the polyheteroarylenes have been detected, and a mechanism of copolymer formation has been proposed.
Putative Role of MicroRNA-Regulated Pathways in Comorbid Neurological and Cardiovascular Disorders
Authors: Hébert Sébastien S.
Published: August 2009

Background. The conserved noncoding microRNAs (miRNAs) that function to regulate
gene expression are essential for the development and function of the brain and heart. Changes in miRNA expression profiles are associated with an increased risk for developing neurodegenerative disorders as well as heart failure. Here, the hypothesis of
how miRNA-regulated pathways could contribute to comorbid neurological and cardiovascular disorders will be discussed. Presentation. Changes in miRNA expression occurring in the brain and heart could have an impact on coexisting neurological and cardiovascular characteristics by (1) modulating organ function, (2) accentuating cellular stress, and (3) impinging on neuronal and/or heart cell survival. Testing. Evaluation of miRNA expression profiles in the brain and heart tissues from individuals with comorbid neurodegenerative and cardiovascular disorders will be of
great importance and relevance. Implications. Careful experimental design will shed light to the deeper understanding of the molecular mechanisms tying up those different but yet somehow connected diseases.
Egomotion and Vection in Young and Elderly Adults
Authors: Haibach Pamela , Slobounov Semyon , Newell Karl
Published: August 2009

Background: Elderly people tend to rely upon their visual input more than upon that from other sensory systems due to age-related declines. This reliance upon vision places older adults at risk for falls because they are often not aware of the magnitude of their body motion. Objective: The purpose of this prospective study was to determine the influence of stationary anchors and vection upon egomotion in young, young-old and old adult age groups using the moving room paradigm. Methods: Forty-five healthy participants separated into 3 age groups (young, 18–20 years; young-old, 60–69 years; old, 70–79 years) were tested. Participants stood on a force platform in front of an oscillating virtual moving room. Optical flow fields were presented to the central and peripheral areas of the retina, individually and jointly. Postural motion was assessed through center of pressure (COP). There were 5 room conditions used to evaluate the role of central and peripheral vision upon postural motion. Participants rated their vection, perceived amount of motion, and the magnitude of the visual scene motion following each condition. Results: In all optical flow conditions, old adults produced more postural motion than the young and young-old adults. Participants were quite accurate at rating their postural motion and vection with their COP displacement; however, young adults rated their vection higher, yet produced significantly less COP displacement than the older adults. Postural responses were also decreased in both age groups when portions of the visual scene were occluded in central or peripheral vision. These findings indicate visual sensitivity to visual scene motion as a function of age when information is available to all areas of the retina. Static images in the visual scene provide a reference point which was found to assist in the stabilization of body position, decreasing fall risk. Conclusions: Older adults exhibited increased egomotion, yet decreased vection in response to visual scene motion. It is likely that the reduction in proprioceptive feedback due to healthy aging induces greater COP motion in the older adults before they perceive visual scene motion, placing them at an increased risk for incurring falls.
Genetic Variation at the
Proprotein Convertase Subtilisin/Kexin Type 5
Gene Modulates High-Density Lipoprotein Cholesterol Levels
Authors: Iatan Iulia , Dastani Zari , Do Ron , Weissglas-Volkov Daphna , Ruel Isabelle , Lee Jenny C. , Huertas-Vazquez Adriana , Taskinen Marja-Riitta , Prat Annik , Seidah Nabil G. , Pajukanta Päivi , Engert James C. , Genest Jacques
Published: August 2009

Background—

A low level of plasma high-density lipoprotein cholesterol (HDL-C) is a risk factor for cardiovascular disease. HDL particles are modulated by a variety of lipases, including endothelial lipase, a phospholipase present on vascular endothelial cells. The
proprotein convertase subtilisin/kexin type 5
(
PCSK5
) gene product is known to directly inactivate endothelial lipase and indirectly cleave and activate angiopoetin-like protein 3, a natural inhibitor of endothelial lipase. We therefore investigated the effect of human
PCSK5
genetic variants on plasma HDL-C levels.

Methods and Results—

Haplotypes at the
PCSK5
locus were examined in 9 multigenerational families that included 60 individuals with HDL-C <10th percentile. Segregation with low HDL-C in 1 family was found. Sequencing of the
PCSK5
gene in 12 probands with HDL-C <5th percentile identified 7 novel variants. Using a 2-stage design, we first genotyped these single-nucleotide polymorphisms (SNPs) along with 163 tagSNPs and 12 additional SNPs (n=182 total) in 457 individuals with documented coronary artery disease. We identified 9 SNPs associated with HDL-C (
P
<0.05), with the strongest results for rs11144782 and rs11144766 (
P
=0.002 and
P
=0.005, respectively). The SNP rs11144782 was also associated with very low-density lipoprotein (
P
=0.039), triglycerides (
P
=0.049), and total apolipoprotein levels (
P
=0.022). In stage 2, we replicated the association of rs11144766 with HDL-C (
P
=0.014) in an independent sample of Finnish low HDL-C families. In a combined analysis of both stages (n=883), region-wide significance of rs11144766 and low HDL-C was observed (unadjusted
P
=1.86�10
−4
and Bonferroni-adjusted
P
=0.031).

Conclusions—

We conclude that variability at the
PCSK5
locus influences HDL-C levels, possibly through the inactivation of endothelial lipase activity, and, consequently, atherosclerotic cardiovascular disease risk.
The Effect of Parkinson's Disease on the Dynamics of On-line and Proactive Cognitive Control during Action Selection
Authors: Wylie Scott A. , Ridderinkhof K. Richard , Bashore Theodore R. , van den Wildenberg Wery P. M.
Published: August 2009

Processing irrelevant visual information sometimes activates incorrect response impulses. The engagement of cognitive control mechanisms to suppress these impulses and make proactive adjustments to reduce the future impact of incorrect impulses may rely on the integrity of frontal–basal ganglia circuitry. Using a Simon task, we investigated the effects of basal ganglia dysfunction produced by Parkinson's disease (PD) on both on-line (within-trial) and proactive (between-trial) control efforts to reduce interference produced by the activation of an incorrect response. As a novel feature, we applied distributional analyses, guided by the activation–suppression model, to differentiate the strength of incorrect response activation and the proficiency of suppression engaged to counter this activation. For situations requiring on-line control, PD (n = 52) and healthy control (n = 30) groups showed similar mean interference effects (i.e., Simon effects) on reaction time (RT) and accuracy. Distributional analyses showed that although the strength of incorrect response impulses was similar between the groups PD patients were less proficient at suppressing these impulses. Both groups demonstrated equivalent and effective proactive control of response interference on mean RT and accuracy rates. However, PD patients were less effective at reducing the strength of incorrect response activation proactively. Among PD patients, motor symptom severity was associated with difficulties in on-line, but not in proactive, control of response impulses. These results suggest that basal ganglia dysfunction produced by PD has selective effects on cognitive control mechanisms engaged to resolve response conflict, with primary deficits in the on-line suppression of incorrect responses occurring in the context of a relatively spared ability to adjust control proactively to minimize future conflict.
Cortical Response to Task-relevant Stimuli Presented outside the Primary Focus of Attention
Authors: Houtkamp Roos , Braun Jochen
Published: August 2009

Visual attention selectively enhances the neural response to a task-relevant item. But what happens when an item outside the primary focus of attention is also relevant to the task at hand? In a dual-task fMRI experiment, we studied the responses in retinotopically organized visual cortex in such a situation. Observers performed an attention-demanding task in the fovea while another, unmasked stimulus appeared in the visual periphery. With respect to this latter stimulus, observers attempted to perform either a less or a more attentionally demanding task. Both tasks increased the BOLD response to the peripheral stimulus. Behaviorally, however, only the less demanding task was performed well, whereas the demanding task was carried out near chance. What could explain the discrepancy between BOLD response and behavioral performance? A control experiment revealed that the report of the less demanding feature was severely disturbed by a mask. Moreover, the visual attributes queried by the demanding task had a significantly shorter iconic memory persistence. We conclude that, in the dual-task situation, the focus of attention initially remains with the foveal task, but subsequently shifts to the former location of the peripheral stimulus. Such a belated shift to a peripheral iconic memory (futile in one case, informative in the other) would reconcile the similar BOLD response with the disparate behavioral performance. In summary, our results show that an enhanced BOLD response is consistently associated with attentional modulation, but not with behavioral performance.
Neural Correlates of Species-typical Illogical Cognitive Bias in Human Inference
Authors: Ogawa Akitoshi , Yamazaki Yumiko , Ueno Kenichi , Cheng Kang , Iriki Atsushi
Published: August 2009

The ability to think logically is a hallmark of human intelligence, yet our innate inferential abilities are marked by implicit biases that often lead to illogical inference. For example, given AB (“if A then B”), people frequently but fallaciously infer the inverse, BA. This mode of inference, called symmetry, is logically invalid because, although it may be true, it is not necessarily true. Given pairs of conditional relations, such as AB and BC, humans reflexively perform two additional modes of inference: transitivity, whereby one (validly) infers AC; and equivalence, whereby one (invalidly) infers CA. In sharp contrast, nonhuman animals can handle transitivity but can rarely be made to acquire symmetry or equivalence. In the present study, human subjects performed logical and illogical inferences about the relations between abstract, visually presented figures while their brain activation was monitored with fMRI. The prefrontal, medial frontal, and intraparietal cortices were activated during all modes of inference. Additional activation in the precuneus and posterior parietal cortex was observed during transitivity and equivalence, which may reflect the need to retrieve the intermediate stimulus (B) from memory. Surprisingly, the patterns of brain activation in illogical and logical inference were very similar. We conclude that the observed inference-related fronto-parietal network is adapted for processing categorical, but not logical, structures of association among stimuli. Humans might prefer categorization over the memorization of logical structures in order to minimize the cognitive working memory load when processing large volumes of information.
Neural Mechanisms of Verb Argument Structure Processing in Agrammatic Aphasic and Healthy Age-matched Listeners
Authors: Thompson Cynthia K. , Bonakdarpour Borna , Fix Stephen F.
Published: August 2009

Processing of lexical verbs involves automatic access to argument structure entries entailed within the verb's representation. Recent neuroimaging studies with young normal listeners suggest that this involves bilateral posterior peri-sylvian tissue, with graded activation in these regions on the basis of argument structure complexity. The aim of the present study was to examine the neural mechanisms of verb processing using fMRI in older normal volunteers and patients with stroke-induced agrammatic aphasia, a syndrome in which verb, as compared to noun, production often is selectively impaired, but verb comprehension in both on-line and off-line tasks is spared. Fourteen healthy listeners and five age-matched aphasic patients performed a lexical decision task, which examined verb processing by argument structure complexity, namely, one-argument [i.e., intransitive (v1)], two-argument [i.e., transitive (v2)], and three-argument (v3) verbs. Results for the age-matched listeners largely replicated those for younger participants studied by Thompson et al. [Thompson, C. K., Bonakdarpour, B., Fix, S. C., Blumenfeld, H. K., Parrish, T. B., Gitelman, D. R., et al. Neural correlates of verb argument structure processing. Journal of Cognitive Neuroscience, 19, 1753–1767, 2007]: v3 − v1 comparisons showed activation of the angular gyrus in both hemispheres and this same heteromodal region was activated in the left hemisphere in the (v2 + v3) − v1 contrast. Similar results were derived for the agrammatic aphasic patients, however, activation was unilateral (in the right hemisphere for three participants) rather than bilateral, likely because these patients' lesions extended to the left temporo-parietal region. All performed the task with high accuracy and, despite differences in lesion site and extent, they recruited spared tissue in the same regions as healthy subjects. Consistent with psycholinguistic models of sentence processing, these findings indicate that the posterior language network is engaged for processing verb argument structure and is crucial for semantic integration of argument structure information.
Mandatory Processing of Irrelevant Fearful Face Features in Visual Search
Authors: Fenker Daniela B. , Heipertz Dorothee , Boehler Carsten N. , Schoenfeld Mircea A. , Noesselt Tömme , Heinze Hans-Jochen , Duezel Emrah , Hopf Jens-Max
Published: August 2009

Faces expressing fear may attract attention in an automatic bottom–up fashion. Here we address this issue with magneto-encephalographic (MEG) recordings in subjects performing a demanding visual search combined with the presentation of irrelevant neutral or fearful faces. The impact of the faces' emotional expression on attentional selection was assessed by analyzing the N2pc component—a modulation of the event-related magnetic field response known to reflect attentional focusing in visual search. We observed that lateralized fearful faces elicited an N2pc approximately between 240 and 400 msec in ventral extrastriate cortex that was independent of the N2pc reflecting target selection in visual search. Despite their clear influence on neural processing, fearful faces did not significantly influence behavioral performance. To clarify this discrepancy, we further performed an MEG experiment in which the demands of the search task were reduced. Under those conditions, lateralized fearful faces elicited an N2pc response that was again independent of the N2pc response to the search target. Behavioral performance was, however, influenced in a significant manner, suggesting that for behavioral effects to appear, sufficient attentional resources need to be left unoccupied by the search task—a notion put forward by the perceptual load theory. Our observations are taken to indicate that irrelevant fearful faces influence attentional processing in extrastriate visual cortex in an automatic fashion and independent of other task-relevant attentional operations. However, this may not necessarily be echoed at the behavioral level as long as task-relevant selection operations exhaust attentional resources.
Lateralized Frontal Eye Field Activity Precedes Occipital Activity Shortly before Saccades: Evidence for Cortico-cortical Feedback as a Mechanism Underlying Covert Attention Shifts
Authors: Gutteling Tjerk P. , van Ettinger-Veenstra Helene M. , Kenemans J. Leon , Neggers Sebastiaan F. W.
Published: August 2009

When an eye movement is prepared, attention is shifted toward the saccade end-goal. This coupling of eye movements and spatial attention is thought to be mediated by cortical connections between the FEFs and the visual cortex. Here, we present evidence for the existence of these connections. A visual discrimination task was performed while recording the EEG. Discrimination performance was significantly improved when the discrimination target and the saccade target matched. EEG results show that frontal activity precedes occipital activity contralateral to saccade direction when the saccade is prepared but not yet executed; these effects were absent in fixation conditions. This is consistent with the idea that the FEF exerts a direct modulatory influence on the visual cortex and enhances perception at the saccade end-goal.