bluuebunny/crossref_metadata_2025 huggingface dataset:
INFLUENCE OF MATTER CREATION ON THE EARLY UNIVERSE STABILITY
Authors: MONTANI GIOVANNI , NESCATELLI NICOLA
Published: February 2008

The effects of the particles creation processes on the evolution of a spatially flat Friedmann–Lemaitre–Robertson–Walker (FLRW) universe are investigated. Our approach is involved in the context of open thermodynamics systems choosing a natural phenomenological ansatz for the particles creation rate. There are reasons to believe that this model gives a simple and appropriate description of the gravitational stability concerning the isotropic model for the Early Universe considered both on a small and large scale. The prelude of our study is that the consideration of the particles production processes are supposed to play an relevant role in the perturbation theory arising in the Early Universe dynamics. We show how perturbations damp forwards in time or remain constant (as in the Cosmological Standard Model) and, differently from the standard analysis, we find instability backward in time from an initial condition on scalar perturbation.
Exploring the links between sediment character, bed material erosion and landscape: implications from a laboratory study of gravels and sand-gravel mixtures
Authors: Frostick Lynne , Murphy Brendan , Middleton Richard
Published: February 2008

Rates of landscape evolution and landform development depend on the capacity of the main transporting medium, predominantly water and the river system, to move material away from the site of production in the upland slopes. In upland areas the main river bed material is coarse gravels, with various admixtures of finer sand and silt. This paper reports a series of flume experiments to investigate the impact of admixtures of finer material on the entrainment of coarse particles. In all experiments the main framework of the bed was made up of quartz-density gravels with a mean particle size of 8 mm. In some of the experiments unimodal, 0.09 mm mean particle size, quartz sands were introduced upstream of the experimental section and transported into place in order to simulate a common condition in natural river beds, of sand migrating over a static gravel bed. New image analysis techniques were developed to extract data from video recordings of the experimental runs. These revealed important differences in entrainment processes among the experiments with a distinctive contrast between the clean gravel and sand–gravel runs. Observations suggest that the presence of sand increases the rates of gravel entrainment and leads to a distinctive patchiness in bed break-up which will encourage bed form development. In the mixtures, sand removal prior to gravel entrainment destabilizes the bed and allows large areas to become entrained. This contrasts with clean gravels where grains tend to entrain individually. These observations show the importance of bed material character in controlling river form and process and point to its role in controlling sediment flux through the landscape.
Perceptual dependencies in information visualization assessed by complex visual search
Authors: Berg Ronald Van den , Cornelissen Frans W. , Roerdink Jos B. T. M.
Published: February 2008

A common approach for visualizing data sets is to map them to images in which distinct data dimensions are mapped to distinct visual features, such as color, size and orientation. Here, we consider visualizations in which different data dimensions should receive equal weight and attention. Many of the end-user tasks performed on these images involve a form of visual search. Often, it is simply assumed that features can be judged independently of each other in such tasks. However, there is evidence for perceptual dependencies when simultaneously presenting multiple features. Such dependencies could potentially affect information visualizations that contain combinations of features for encoding information and, thereby, bias subjects into unequally weighting the relevance of different data dimensions. We experimentally assess (1) the presence of judgment dependencies in a visualization task (searching for a target node in a node-link diagram) and (2) how feature contrast relates to salience. From a visualization point of view, our most relevant findings are that (a) to equalize saliency (and thus bottom-up weighting) of size and color, color contrasts have to become very low. Moreover, orientation is less suitable for representing information that consists of a large range of data values, because it does not show a clear relationship between contrast and salience; (b) color and size are features that can be used independently to represent information, at least as far as the range of colors that were used in our study are concerned; (c) the concept of (static) feature salience hierarchies is wrong; how salient a feature is compared to another is not fixed, but a function of feature contrasts; (d) final decisions appear to be as good an indicator of perceptual performance as indicators based on measures obtained from individual fixations. Eye tracking, therefore, does not necessarily present a benefit for user studies that aim at evaluating performance in search tasks.
Analysis and optimization of prediction-based flow control in networks-on-chip
Authors: Ogras Umit Y. , Marculescu Radu
Published: February 2008

Networks-on-Chip (NoC) communication architectures have emerged recently as a scalable solution to on-chip communication problems. While the NoC architectures may offer higher bandwidth compared to traditional bus-based communication, their performance can degrade significantly in the absence of effective flow control algorithms. Unfortunately, flow control algorithms developed for macronetworks, either rely on local information, or suffer from large communication overhead and unpredictable delays. Hence, using them in the NoC context is problematic at best. For this reason, we propose a predictive closed-loop flow control mechanism and make the following contributions: First, we develop traffic source and router models specifically targeted to NoCs. Then, we utilize these models to predict the possible congestion in the network. Based on this information, the proposed scheme controls the packet injection rate at traffic sources in order to regulate the total number of packets in the network. We also illustrate the proposed traffic source model and the applicability of the proposed flow controller to actual designs using real NoC implementations. Finally, simulations and experimental study using our FPGA prototype show that the proposed controller delivers a better performance compared to the traditional switch-to-switch flow control algorithms under various real and synthetic traffic patterns.
Optimizing wirelength and routability by searching alternative packings in floorplanning
Authors: Sham Chiu-Wing , Young Evangeline F. Y. , Zhou Hai
Published: February 2008

Recent advances in VLSI technology have made optimization of the interconnect delay and routability of a circuit more important. We should consider interconnect planning as early as possible. We propose a postfloorplanning step to reduce the interconnect cost of a floorplan by searching alternative packings. If a packing contains a rectangular bounding box of a group of modules, we can rearrange the blocks in the bounding box to obtain a new floorplan with the same area, but possibly with a smaller interconnect cost. Experimental results show that we can reduce the interconnect cost of a packing without any penalty in area.
2D Euclidean distance transform algorithms
Authors: Fabbri Ricardo , Costa Luciano Da F. , Torelli Julio C. , Bruno Odemir M.
Published: February 2008

The distance transform (DT) is a general operator forming the basis of many methods in computer vision and geometry, with great potential for practical applications. However, all the optimal algorithms for the computation of the exact Euclidean DT (EDT) were proposed only since the 1990s. In this work, state-of-the-art sequential 2D EDT algorithms are reviewed and compared, in an effort to reach more solid conclusions regarding their differences in speed and their exactness. Six of the best algorithms were fully implemented and compared in practice.
Peer-based computer-supported knowledge refinement
Authors: Cho Kwangsu , Chung Tingting Rachel , King William R. , Schunn Christian
Published: February 2008

Nonexpert peer-based knowledge refinement, it turns out, is just as helpful as expert-centric knowledge refinement for improving the quality of results.
Storage optimization for large-scale distributed stream-processing systems
Authors: Hildrum Kirsten , Douglis Fred , Wolf Joel L. , Yu Philip S. , Fleischer Lisa , Katta Akshay
Published: February 2008

We consider storage in an extremely large-scale distributed computer system designed for stream processing applications. In such systems, both incoming data and intermediate results may need to be stored to enable analyses at unknown future times. The quantity of data of potential use would dominate even the largest storage system. Thus, a mechanism is needed to keep the data most likely to be used. One recently introduced approach is to employ retention value functions, which effectively assign each data object a value that changes over time in a prespecified way [Douglis et al.2004]. Storage space for data entering the system is reclaimed automatically by deleting data of the lowest current value. In such large systems, there will naturally be multiple file systems available, each with different properties. Choosing the right file system for a given incoming stream of data presents a challenge. In this article we provide a novel and effective scheme for optimizing the placement of data within a distributed storage subsystem employing retention value functions. The goal is to keep the data of highest overall value, while simultaneously balancing the read load to the file system. The key aspects of such a scheme are quite different from those that arise in traditional file assignment problems. We further motivate this optimization problem and describe a solution, comparing its performance to other reasonable schemes via simulation experiments.
Provably Secure Timed-Release Public Key Encryption
Authors: Cheon Jung Hee , Hopper Nicholas , Kim Yongdae , Osipkov Ivan
Published: February 2008

A timed-release cryptosystem allows a sender to encrypt a message so that only the intended recipient can read it only after a specified time. We formalize the concept of a secure timed-release public-key cryptosystem and show that, if a third party is relied upon to guarantee decryption after the specified date, this concept is equivalent to identity-based encryption; this explains the observation that all known constructions use identity-based encryption to achieve timed-release security. We then give several provably-secure constructions of timed-release encryption: a generic scheme based on any identity-based encryption scheme, and two more efficient schemes based on the existence of cryptographically admissible bilinear mappings. The first of these is essentially as efficient as the Boneh-Franklin Identity-Based encryption scheme, and is provably secure and authenticated in the random oracle model; the final scheme is not authenticated but is provably secure in the standard model (i.e., without random oracles).
High-performance packet classification algorithm for multithreaded IXP network processor
Authors: Liu Duo , Chen Zheng , Hua Bei , Yu Nenghai , Tang Xinan
Published: February 2008

Packet classification is crucial for the Internet to provide more value-added services and guaranteed quality of service. Besides hardware-based solutions, many software-based classification algorithms have been proposed. However, classifying at 10 Gbps speed or higher is a challenging problem and it is still one of the performance bottlenecks in core routers. In general, classification algorithms face the same challenge of balancing between high classification speed and low memory requirements. This paper proposes a modified recursive flow classification (RFC) algorithm, Bitmap-RFC, which significantly reduces the memory requirements of RFC by applying a bitmap compression technique. To speed up classifying speed, we exploit the multithreaded architectural features in various algorithm development stages from algorithm design to algorithm implementation. As a result, Bitmap-RFC strikes a good balance between speed and space. It can significantly keep both high classification speed and reduce memory space consumption. This paper investigates the main NPU software design aspects that have dramatic performance impacts on any NPU-based implementations:
memory space reduction
,
instruction selection
,
data allocation
,
task partitioning
, and
latency hiding
. We experiment with an architecture-aware design principle to guarantee the high performance of the classification algorithm on an NPU implementation. The experimental results show that the Bitmap-RFC algorithm achieves 10 Gbps speed or higher and has a good scalability on Intel IXP2800 NPU.
The theoretic center of computer science
Authors: Kuhn Michael , Wattenhofer Roger
Published: February 2008

In this article we examine computer science in general, and theory and distributed computing in particular. We present a map of the computer science conferences, speculating about the center of computer science. In addition we present some trends and developments. Finally we revisit centrality, wondering about the central actors in computer science. This article is a printed version of a frivolous PODC 2007 business meeting talk, held by the second author. In an attempt to address a broader audience we have extended the content by data about theory conferences and computer science in general. Still, the character of the information remains the same, meaning our investigations should not be taken too seriously.
Introduction
Authors: Pucella Riccardo
Published: February 2008

A short column this time around. Simon Kramer sent me a synopsis of his Ph.D. thesis, defended earlier this year at l'École Polytechnique Fédérale de Lausanne. He introduces a new logic for reasoning about cryptographic protocol called CPL (Cryptographic Protocol Logic). The result is an intriguing blend of modal logic and process algebra, reminiscent of spatial logics for process calculi, but extended with knowledge, belief, and provability operators.
Blogger ethics and YouTube common sense
Authors: Martin C. Dianne
Published: February 2008

As our students live more of their lives on the internet using sites such as Facebook, YouTube, personal blogs and Second Life, those of us in the older generations may need to rethink how we can better mentor them to become good web citizens. Recently there have been a number of interesting controversies around sites that allow people to publish very personal glimpses into their lives or anonymous opinions. The posting of the video Obama Girl and similar bogus videos related to political candidates on YouTube has the potential to influence a presidential election. The recent discovery that John Makey, the CEO of Whole Foods, anonymously authored a blog that praised his company and slammed a rival he was trying to acquire in an attempt to manipulate stock prices has raised eyebrows at the Federal Trade Commission and resulted in a probe by the Securities and Exchange Commission for possible illegal actions. Many college students are finding out that dumb photos of themselves appearing to be drunk or on drugs, which they posted on FaceBook as a joke along with language to support the ruse, are now preventing them from getting jobs or security clearances. The site Second Life has generated both millionaires and bankruptcies as people vie to sell virtual space to each other.
The Randolph thesis
Authors: Lister Raymond
Published: February 2008

Justus Randolph recently completed a PhD dissertation which is a methodological review of computer science education research. His review is based upon 352 CSEd articles published between 2000 and 2005. While I do not agree with all aspects of Randolph's argument, it is a thought provoking dissertation. It is downloadable from a website [2] and I believe that most people who are active in CSEd Research should read it. To whet your appetite for the entire dissertation, I recommend that you first read the paragraph at the top of page 162, which begins "
The typical computer science education research paper is . . .
"
Visions of a future ... without forgetting the past
Authors: Hawthorne Elizabeth K.
Published: February 2008

In his last column,
Reflections on a History
, Robert D. Campbell bade farewell as chair of the ACM Two-Year College Education Committee (TYCEC). On behalf of all committee members past and present, it is my pleasure and privilege as incoming chair to thank Bob for all his countless hours of service to the TYCEC over the past fourteen years. As chair for the last six years, Bob lead the committee to an exceptional record of accomplishment and by doing so continued the fine reputation of the committee. We extend our deepest appreciation for your personal dedication and noteworthy contributions. Likewise, we are so delighted to have ongoing access to your unique talents and vast experience as you remain a committee member and invaluable mentor. You most certainly will be a hard act to follow. I will endeavor to carry on your momentum as well as those of past chairs to promote this committee's extraordinary history into the foreseeable future.
More on IFIP educational activities
Authors: Turner A. Joe
Published: February 2008

This column provides a summary of some recent and upcoming IFIP events.
Head in the clouds
Authors: Astrachan Owen
Published: February 2008

Once upon a time I was a boy in high school who listened to the Firesign Theatre Group and wondered what one of their phrases meant: "How can you be in two places at once when you're not anywhere at all." Today I am thinking of a similar phrase, one I think may apply to many of our introductory courses: "How can we teach problem-solving when we're not solving real problems at all." Of course I have something in mind when I use the phrase
real problem
. Before I describe what I have in mind I'll take a liberty and describe what I don't have in mind: I don't have in mind Towers of Hanoi to illustrate recursion; I don't have in mind a program printing the verses of 'Old MacDonald had a Farm' to illustrate methods and parameters; I don't have in mind employees, hourly employees, and salaried employees to illustrate inheritance. I confess, however, to having used all these examples at some point, but I've abandoned them for a higher cause: the cause of using real problems. My bias is that the real problems we use should come from the academic disciplines our students know about and are close to. For my students these include computer science, biology, economics, sociology, physics, and mathematics. But I am biased even further and I'm staying away from number theory, combinatorics, and inclined planes. That doesn't mean we shouldn't use songs to illustrate parameter passing or employees to illustrate inheritance. We should use these as metaphors and analogies to ground the concepts in terms the students understand. However, these examples should not be the ultimate goal in what we want our students to understand --- they should be tools we use in explaining the concepts we need to understand real problems.
Eliciting an overlooked aspect of Bayesian reasoning
Authors: Yang Feng-Jen
Published: February 2008

Bayesian theorem is the theoretical basis of uncertainty management as well as the stochastic foundation for forecast-oriented expert systems. Mathematically, the reasoning steps can be represented by a sequence of probabilistic computations. To reduce the mathematical complexity and make it mentally manageable, an assumption, known as Bayesian Assumption, is usually made. This assumption does simplify the computation, but also introduces errors to the computation and makes it distorted from the real probabilistic result. In this paper, I use Venn diagrams to discuss the distortion being introduced to the result by showing cases from
best-fitted, partial-fitted to worst-fitted
.
Prolog as the first programming language
Authors: Fleck Arthur
Published: February 2008

The adoption of logic programming in an introductory course on computer programming offers several rewards. The higher conceptual level of this programming paradigm guides students to an early appreciation for abstraction. The descriptive character of programs makes them more understandable than conventional programs, and the relational basis makes them more versatile. This incremental and highly interactive style of programming leads to early student success and motivates active participation by students.
Formal languages through web forms and regular expressions
Authors: Blanco Arbe José Miguel , Ortega Ana Sánchez , Mártinez-Conde Jesús Ibáñez
Published: February 2008

We present a practical and up-to-date proposal to teach formal languages. It takes advantage of frequent use of regular-expressions to specify entry data forms in different contexts and, particularly, in three-layer web applications. Compared to more classical approaches our method improves significantly the acquainting of students with the immediate practical utility of the concepts involved in formal language definition. Students must develop code fragments based on JavaScript notation of regular-expressions. Accordingly, any web browser can be a suitable platform for the execution of solutions. The experience has proved to be effective and well-accepted by students and teachers.
Computer applications
Authors: Sattar Abdul , Lorenzen Torben
Published: February 2008

A paperless computer applications course, which is driven by an online syllabus is described. Students demo their work on the computer rather than hand in paper assignments. Several advanced topics are included to challenge the students and downloads are provided to minimize the amount of student busywork. The use of weekly lecture and assignment downloads allow instructors to teach sections with twenty-five students with no graduate student or clerical support.
Improving the teaching of object-oriented design knowledge
Authors: Garzás Javier , Piattini Mario
Published: February 2008

In the general sphere of the teaching of software engineering concepts, it can be noted that there are very few pieces of work dealing with how to get across, through teaching, the practical experience that has been built up on the subject of object-oriented design. The few works that do exist focus on design patterns. Pattern catalogues, however, do not completely resolve the problem of imparting the experience about object-oriented design, an area where it is clear that the greatest benefit derived from the patterns is achieved when their designers are already-experienced. What is more, other elements associated with object-oriented knowledge, such as principles, heuristics, best practices, bad smells, etc., are components related to practical knowledge of design. These are barely taken into consideration, however. In an effort to solve these problems, we put forward an ontology which brings together and integrates object-oriented design which improves teaching, amongst other things. It makes the great quantity of knowledge that has been built up clearer and brings it together into a united whole. It is thus possible to create catalogues of integrated knowledge.
Concepts to real world implementation via service learning
Authors: Kawell Greg
Published: February 2008

This paper presents the experience I had implementing a Service Learning component into a Operating System/Networking 300 level course. The goal was to get the students to take the concepts from the classroom and textbook and use them to solve real world problems that would affect real people. The method for measuring the effects of this project was the journal entries students kept throughout the semester. In the end, the students not only successfully applied the concepts but felt they had gone beyond the material presented in the classroom and had an impact on the world around them.
Training to persist in computing careers
Authors: Smith Wanda J. , Bélanger France , Lewis Tracy L. , Honaker Kristi
Published: February 2008

Funded by a SIGCSE Special Project grant, Training to Persist in Computing Careers is a hands-on resource for faculty interested in incorporating soft skills training in IT-related courses. Soft skills include such abilities as controlling and using one's emotions (emotional intelligence), dealing with team issues and stress (coping strategies) and using business-appropriate language. These skills are increasingly recognized as key to success in IT-related disciplines [1, 5].
Developing a computer science-specific learning taxonomy
Authors: Fuller Ursula , Johnson Colin G. , Ahoniemi Tuukka , Cukierman Diana , Hernán-Losada Isidoro , Jackova Jana , Lahtinen Essi , Lewis Tracy L. , Thompson Donna McGee , Riedesel Charles , Thompson Errol
Published: February 2008

Bloom's taxonomy of the cognitive domain and the SOLO taxonomy are being increasingly widely used in the design and assessment of courses, but there are some drawbacks to their use in computer science. This paper reviews the literature on educational taxonomies and their use in computer science education, identifies some of the problems that arise, proposes a new taxonomy and discusses how this can be used in application-oriented courses such as programming.
Introduction
Authors: Keim Daniel A. , Schneidewind Joern
Published: February 2008

The information overload is a well-known phenomenon of the information age, since due to the progress in computer power and storage capacity over the last decades, data is produced at an incredible rate, and our ability to collect and store these data is increasing at a faster rate than our ability to analyze it. But, the analysis of these massive, typically messy and inconsistent, volumes of data is crucial in many application domains. For decision makers, analysts or emergency response teams it is an essential task to rapidly extract relevant information from the flood of data.
Impaired lymphatic cerebrospinal fluid absorption in a rat model of kaolin-induced communicating hydrocephalus
Authors: Nagra G. , Li J. , McAllister J. P. , Miller J. , Wagshul M. , Johnston M.
Published: February 2008

It has been assumed that the pathogenesis of hydrocephalus includes a cerebrospinal fluid (CSF) absorption deficit. Because a significant portion of CSF absorption occurs into extracranial lymphatics located in the olfactory turbinates, the purpose of this study was to determine whether CSF transport was compromised at this location in a kaolin-induced communicating (extraventricular) hydrocephalus model in rats. Under 1–3% halothane anesthesia, kaolin ( n = 10) or saline ( n = 9) was introduced into the basal cisterns of Sprague-Dawley rats, and the development of hydrocephalus was assessed 1 wk later using MRI. After injection of human serum albumin (125I-HSA) into a lateral ventricle, the tracer enrichment in the olfactory turbinates 30 min postinjection provided an estimate of CSF transport through the cribriform plate into nasal lymphatics. Lateral ventricular volumes in the kaolin group (0.073 ± 0.014 ml) were significantly greater than those in the saline-injected animals (0.016 ± 0.001 ml; P = 0.0014). The CSF tracer enrichment in the olfactory turbinates (expressed as percent injected/g tissue) in the kaolin rats averaged 0.99 ± 0.39 and was significantly lower than that measured in the saline controls (5.86 ± 0.32; P < 0.00001). The largest degree of ventriculomegaly was associated with the lowest levels of lymphatic CSF uptake with lateral ventricular expansion occurring only when almost all of the lymphatic CSF transport capacity had been compromised. We conclude that lymphatic CSF absorption is impaired in a kaolin-communicating hydrocephalus model and that the degree of this impediment may contribute to the severity of the induced disease.
Protein kinase C inhibits caveolae-mediated endocytosis of TRPV5
Authors: Cha Seung-Kuy , Wu Tao , Huang Chou-Long
Published: February 2008

Transient receptor potential vanilloid 5 (TRPV5) constitutes the apical entry pathway for transepithelial Ca2+reabsorption in kidney. Many hormones alter renal Ca2+reabsorption at least partly by regulating TRPV5. The mechanism for acute regulation of TRPV5 by phospholipase C-coupled hormones is largely unknown. Here, we found that protein kinase C (PKC) activator 1-oleoyl-acetyl-sn-glycerol (OAG) increased TRPV5 current density and surface abundance in cultured cells. The OAG-mediated increase of TRPV5 was prevented by preincubation with specific PKC inhibitors. Coexpression with a dominant-negative dynamin increased the basal TRPV5 current density and prevented the increase by OAG. Knockdown of caveolin-1 by small interference RNA (siRNA) prevented the increase of TRPV5 by OAG. In contrast, knockdown of clathrin heavy chain had no effects. OAG had no effect on TRPV5 expressed in caveolin-1 null cells derived from caveolin-1 knockout mice. Forced expression of recombinant caveolin-1 restored the regulation of TRPV5 by OAG in caveolin-1 knockout cells. Mutations of serine-299 and/or serine-654 of TRPV5 (consensus residues for phosphorylation by PKC) abolished the regulation by OAG. Parathyroid hormone (PTH) increased TRPV5 current density in cells coexpressing TRPV5 and type 1 PTH receptor. The increase caused by PTH was prevented by PKC inhibitor, mutation of serine-299/serine-654, or by knockdown of caveolin-1. Thus, TRPV5 undergoes constitutive caveolae-mediated endocytosis. Activation of PKC increases cell surface abundance of TRPV5 by inhibiting the endocytosis. This mechanism of regulation by PKC may contribute to the acute stimulation of TRPV5 and renal Ca2+reabsorption by PTH.
Renal medullary ETBreceptors produce diuresis and natriuresis via NOS1
Authors: Nakano Daisuke , Pollock Jennifer S. , Pollock David M.
Published: February 2008

Endothelin-1 (ET-1) plays an important role in the regulation of salt and water excretion in the kidney. Considerable in vitro evidence suggests that the renal medullary ETBreceptor mediates ET-1-induced inhibition of electrolyte reabsorption by stimulating nitric oxide (NO) production. The present study was conducted to test the hypothesis that NO synthase 1 (NOS1) and protein kinase G (PKG) mediate the diuretic and natriuretic effects of ETBreceptor stimulation in vivo. Infusion of the ETBreceptor agonist sarafotoxin S6c (S6c: 0.45 μg·kg−1·h−1) in the renal medulla of anesthetized, male Sprague-Dawley rats markedly increased the urine flow (UV) and urinary sodium excretion (UNaV) by 67 and 120%, respectively. This was associated with an increase in medullary cGMP content but did not affect blood pressure. In addition, S6c-induced diuretic and natriuretic responses were absent in ETBreceptor-deficient rats. Coinfusion of NG-propyl-l-arginine (10 μg·kg−1·h−1), a selective NOS1 inhibitor, suppressed S6c-induced increases in UV, UNaV, and medullary cGMP concentrations. Rp-8-Br-PET-cGMPS (10 μg·kg−1·h−1) or RQIKIWFQNRRMKWKK-LRK5H-amide (18 μg·kg−1·h−1), a PKG inhibitor, also inhibited S6c-induced increases in UV and UNaV. These results demonstrate that renal medullary ETBreceptor activation induces diuretic and natriuretic responses through a NOS1, cGMP, and PKG pathway.
Melanopsin Ganglion Cells Use a Membrane-Associated Rhabdomeric Phototransduction Cascade
Authors: Graham Dustin M. , Wong Kwoon Y. , Shapiro Peter , Frederick Courtney , Pattabiraman Kartik , Berson David M.
Published: February 2008

Intrinsically photosensitive retinal ganglion cells (ipRGCs) are photoreceptors of the mammalian eye that drive pupillary responses, synchronization of circadian rhythms, and other reflexive responses to daylight. Melanopsin is the ipRGC photopigment, but the signaling cascade through which this invertebrate-like opsin triggers the photocurrent in these cells is unknown. Here, using patch-clamp recordings from dissociated ipRGCs in culture, we show that a membrane-associated phosphoinositide cascade lies at the heart of the ipRGC phototransduction mechanism, similar to the cascade in rhabdomeric photoreceptors of invertebrate eyes. When ipRGCs were illuminated, melanopsin activated a G protein of the Gq/11class, stimulating the effector enzyme phospholipase C. The presence of these signaling components in ipRGCs was confirmed by single-cell RT-PCR and immunofluorescence. The photoresponse was fully functional in excised inside-out patches of ipRGC membrane, indicating that all core signaling components are within or tightly coupled to the plasma membrane. The striking similarity of phototransduction in ipRGCs and invertebrate rhabdomeric photoreceptors reinforces the emerging view that these cells have a common evolutionary origin.
State Trajectories Analysis for a Class of Tubular Reactor Nonlinear Nonautonomous Models
Authors: Aylaj B. , Achhab M. E. , Laabissi M.
Published: February 2008

The existence and uniqueness of global mild solutions are proven for a class of semilinear nonautonomous evolution equations. Moreover, it is shown that the system, under
considerations, has a unique steady state. This analysis uses,
essentially, the dissipativity, a subtangential condition, and the
positivity of the related C0‐semigroup.
CDBA-Based Universal Biquad Filter and Quadrature Oscillator
Authors: Tangsrirat Worapong , Pukkalanun Tattaya , Surakampontorn Wanlop
Published: February 2008

The voltage-mode universal biquadratic filter and sinusoidal quadrature oscillator based on the use of current differencing buffered amplifiers (CDBAs) as active components have been proposed in this paper. All the proposed configurations employ only two CDBAs and six passive components. The first proposed CDBA-based biquad configuration can realize all the standard types of the biquadratic functions, that is, lowpass, bandpass, highpass, bandstop, and allpass, from the same topology, and can also provide orthogonal tuning of the natural angular frequency(ωo)and the bandwidth (BW) through separate virtually grounded passive components. By slight modification of the first proposed configuration, the new CDBA-based sinusoidal quadrature oscillator is easily obtained. The oscillation condition and the oscillation frequency are independently adjustable by different virtually grounded resistors. The sensitivity analysis of all proposed circuit configurations is shown to be low. PSPICE simulations and experimental results based upon commercially available AD844-type CFAs are included, which confirm the workability of the proposed circuits.
Effect of C‐Peptide on Diabetic Neuropathy in Patients with Type 1 Diabetes
Authors: Ekberg Karin , Johansson Bo-Lennart
Published: February 2008

Recent results indicate that proinsulin C‐peptide, contrary
to previous views, exerts important physiological effects and
shows the characteristics of a bioactive peptide. Studies in
type 1 diabetes, involving animal models as well as patients,
demonstrate that C‐peptide in replacement doses has the
ability to improve peripheral nerve function and prevent or
reverse the development of nerve structural abnormalities.
Peripheral nerve function, as evaluated by determination of
sensory nerve conduction velocity and quantitative sensory
testing, is improved by C‐peptide replacement in diabetes type
1 patients with early stage neuropathy. Similarly, autonomic
nerve dysfunction is ameliorated following administration of C
peptide for up to 3 months. As evaluated in animal models of
type 1 diabetes, the improved nerve function is accompanied by
reversal or prevention of nerve structural changes, and the
mechanisms of action are related to the ability of C‐peptide
to correct diabetes‐induced reductions in endoneurial blood
flow and in Na+, K+‐ATPase activity and modulation of neurotrophic
factors. Combining the results demonstrates that C‐peptide may be
a possible new treatment of neuropathy in type 1 diabetes.
Precise Point Positioning for TAI Computation
Authors: Petit Gérard , Jiang Zhiheng
Published: February 2008

We discuss the use of some new time transfer techniques for computing TAI time links. Precise point positioning (PPP) uses GPS dual frequency carrier phase and code measurements to compute the link between a local clock and a reference time scale with the precision of the carrier phase and the accuracy of the code. The time link between any two stations can then be computed by a simple difference. We show that this technique is well adapted and has better short‐term stability than other techniques used in TAI. We present a method of combining PPP and two‐way time transfer that takes advantage of the qualities of each technique, and shows that it would bring significant improvement to TAI links.
Outcome Evaluation of the Intergroup Project
Authors: Spencer Michael S. , Brown Mikel , Griffin Shayla , Abdullah Shabana
Published: February 2008

Using both quantitative data based on pre-post test questionnaires and qualitative data based on personal interviews with program participants, the authors examine the outcomes of students' experiences in a school-based intervention for improving intergroup relations between adolescents at two high schools. Specifically, the authors investigate whether students increase their awareness of social identities and intergroup conflict, their level of competence with dialogue and intergoup understanding, and their capacity for social action around intergroup conflict. The findings demonstrate that the intervention was successful in increasing students' critical social awareness and developing skills for conflict reduction and promoting intergroup relations. The authors discuss the implications of these findings for research and practice.
Parent Training in Groups: Pilot Study with Parents of Infants with Developmental Delay
Authors: Niccols Alison , Mohamed Shaheen
Published: February 2008

This paper describes an innovative 8-week parent-child interaction skills training group for parents of infants with developmental delay. We developed the "Skill Building Group" within an attachment theory framework. Parents actively learned skills in sensitive responding to infant cues through small and large group discussion of video segments of common parenting challenges, homework assignments, and peer support. We conducted a pilot study comparing 12 participants and 5 controls on several self-report pre-test/post-test measures. Results for the intervention group indicated decreases in dysfunctional parent-child interaction, parental distress, sadnessldepression, and follow-up service utilization, and high levels of consumer satisfaction. For the comparison group, pre-post differences were not significant.
Effects of Toys or Group Composition for Children With Disabilities: A Synthesis
Authors: Kim Ae-Hwa , Vaughn Sharon , Elbaum Batya , Hughes Marie Tejero , Morris Sloan Claire V. , Sridhar Dheepa
Published: February 2008

This synthesis reviewed the findings of 13 intervention studies, published between 1975 and June 1999, that examined the effects of manipulation of toys or group composition on social behaviors of 3- to 5-year-old children with disabilities. The purpose, participants, intervention, measurement, and findings of each study are described. An analysis of study outcomes is provided for (a) toy effect, (b) group composition effect, and (c) toy effect combined with group composition effect. Positive outcomes were associated with children's playing with social toys and play groups that included children with and without disabilities.
Using Planning Time to Individualize Instruction for Preschoolers With Special Needs
Authors: Grisham-Brown Jennifer , Pretti-Frontczak Kristie
Published: February 2008

Teacher planning time is essential for ensuring individualized, intentional instruction for young children with disabilities in community-based settings. The purpose of this study was to describe how preschool teachers plan classroom activities or events, how they describe procedures used to individualize instruction for children with disabilities, and challenges they face in planning effective, individualized instruction. Data were gathered through a written questionnaire completed by 453 teachers and a series of three focus groups. Findings offer initial descriptions of the planning processes of preschool teachers in relation to individualizing instruction, and suggest that planning for individualized instruction is a complex process. Study limitations, in terms of the sample and data collection methods, and suggestions for future research on teacher planning are discussed.
Issues in Designing State Accountability Systems
Authors: Harbin Gloria , Rous Beth , Mclean Mary
Published: February 2008

A pressing need exists within the field of early intervention and early childhood special education to identify and measure outcomes for young children and their families as a result of participating in publicly funded services. This article identifies critical issues for state administrators, providers, families, and researchers to consider when designing state-level accountability systems. The article explains the complexities of multiple federal accountability initiatives, confusion over terms used in various accountability initiatives (e.g. standards versus outcomes), multiple levels and types of accountability initiatives, and challenges faced in identifying and measuring standards and outcomes. Specific information is provided to facilitate the design of accountability systems that support the inclusion of young children with disabilities.
Alcohol and Drug Abuse Among Sexual and Nonsexual Offenders: Relationship to Intimacy Deficits and Coping Strategy
Authors: Looman Jan , Abracen Jeffrey , DiFazio Roberto , Maillet Greg
Published: February 2008

Three groups of subjects (N = 95) consisting or rapists, child molesters, and a comparison group of violent offenders were examined with reference to history of alcohol abuse, history of drug abuse, intimacy deficits, and emotionally based coping strategies. No differences were found between the two groups of sex offenders on any of the measures examined. Sex offenders were found to be significantly older than the comparison group. When age was entered as a covariate sex offenders were found to have significantly more difficulties with alcohol use as measured by the Michigan Alcohol Screening Test (MAST) and were significantly more likely to use emotionally based coping strategies as measured by the Coping Inventory for Stressful Situations (CISS). No differences were found between any of the groups with reference to drug abuse as measured by the Drug Abuse Screening Test (DAST). Results are discussed in terms of Marshall's theory of intimacy deficits in sexual offenders.
The Criminal Histories and Later Offending of Child Pornography Offenders
Authors: Seto Michael C. , Eke Angela W.
Published: February 2008

The likelihood that child pornography offenders will later commit a contact sexual offense is unknown. In the present study, we identified a sample of 201 adult male child pornography offenders using police databases and examined their charges or convictions after the index child pornography offense(s). We also examined their criminal records to identify potential predictors of later offenses: 56% of the sample had a prior criminal record, 24% had prior contact sexual offenses, and 15% had prior child pornography offenses. One-third were concurrently charged with other crimes at the time they were charged for child pornography offenses. The average time at risk was 2.5 years; 17% of the sample offended again in some way during this time, and 4% committed a new contact sexual offense. Child pornography offenders with prior criminal records were significantly more likely to offend again in any way during the follow-up per-iod. Child pornography offenders who had committed a prior or concurrent contact sexual offense were the most likely to offend again, either generally or sexually.
Topology of Female Sex Offenders: A Test of Vandiver and Kercher
Authors: Sandler Jeffrey C. , Freeman Naomi J.
Published: February 2008

Using all 390 female sex offenders registered in New York State, this study attempted to test the analyses and findings of Vandiver and Kercher (2004). Although the current sample varied geographically from Vandiver and Kercher's sample, they were remarkably similar on key demographic variables (e.g., offender age and race, victim age), allowing for close comparison of the findings. Results of the hierarchical loglinear modeling analysis reinforced the importance of variables such as victim and offender ages to categorizing offenders. The present cluster analysis indicated the existence of six distinct types of female sex offender (with the clusters themselves differing substantially from those found by Vandiver and Kercher), supporting the view that female sex offenders are a heterogeneous group.
Denial Predicts Recidivism for Some Sexual Offenders
Authors: Nunes Kevin L. , Hanson R. Karl , Firestone Philip , Moulden Heather M. , Greenberg David M. , Bradford John M.
Published: February 2008

This study examined whether there were variables that moderated the relationship between denial and recidivism among adult male sexual offenders. The first study (N=489) found that the relationship with sexual recidivism was moderated by risk (as measured by the Rapid Risk Assessment for Sexual Offense Recidivism) but not by psychopathy (as measured by the Psychopathy Checklist-Revised). Contrary to expectations, denial was associated with increased sexual recidivism among the low-risk offenders and with decreased recidivism among the high-risk offenders. Post hoc analyses suggested that the risk item most responsible for the interaction was "relationship to victims". For incest offenders, denial was associated with increased sexual recidivism, but denial was not associated with increased recidivism for offenders with unrelated victims. These interactions were substantially replicated in two independent samples (N=490 and N=73). The results suggest that denial merits further consideration for researchers as well as those involved in applied risk assessment of sexual offenders.
Brief event
Authors: Pedersen David
Published: February 2008

This article explores the challenge of how to make sense of ethnographic moments, which are saturated with qualities of immediacy, abruptness, and the faltering of subjective expectations. It approaches the problem through the theoretical lens of nominalism versus realism and, drawing on Marx's inquiries into value formation and Peirce's semiotic logic, develops an approach predicated on discerning a three-way recursively embedded relationship among `the potential', `the actual' and `the general'. The article argues that such a modality — a `realist semiotic of value' — illuminates a great deal more than is otherwise visible and does so in a way that has important political and ethical implications for the subjects involved.