bluuebunny/crossref_metadata_2025 huggingface dataset:
What is the future of disk drives, death or rebirth?
Authors: Deng Yuhui
Published: May 2011

Disk drives have experienced dramatic development to meet performance requirements since the IBM 1301 disk drive was announced in 1961. However, the performance gap between memory and disk drives has widened to 6 orders of magnitude and continues to widen by about 50% per year. Furthermore, energy efficiency has become one of the most important challenges in designing disk drive storage systems. The architectural design of disk drives has reached a turning point which should allow their performance to advance further, while still maintaining high reliability and energy efficiency. This article explains how disk drives have evolved over five decades to meet challenging customer demands. First of all, it briefly introduces the development of disk drives, and deconstructs disk performance and power consumption. Secondly, it describes the design constraints and challenges that traditional disk drives are facing. Thirdly, it presents some innovative disk drive architectures discussed in the community. Fourthly, it introduces some new storage media types and the impacts they have on the architecture of the traditional disk drives. Finally, it discusses two important evolutions of disk drives: hybrid disk and solid state disk. The article highlights the challenges and opportunities facing these storage devices, and explores how we can expect them to affect storage systems.
The area perspective transform
Authors: Hunt Warren A. , Johnson Gregory S.
Published: May 2011

A key problem in applications such as soft shadows and defocus blur is to identify points or primitives which are inside a volume of space. For example, the soft shadow computation involves finding surfaces which pass in front of an area light as viewed from a point
p
in the scene. The desired surfaces are those which are inside a frustum defined by the light and
p
, and can be found by intersecting the frustum with an acceleration structure over geometry. However, accurately computing this intersection is computationally intensive.

In this article, we introduce a homogeneous transform which reduces the computation required to determine the set of points or primitives which are inside a tetrahedral volume. The transform converts tetrahedra into axis-aligned boxes, substantially reducing the cost of intersection with an axis-aligned acceleration structure over points or primitives. We describe the application of this transform to soft shadows and defocus blur, and briefly consider potential uses of the underlying mathematical approach in higher-dimensional problems.
Frequency analysis and sheared filtering for shadow light fields of complex occluders
Authors: Egan Kevin , Hecht Florian , Durand Frédo , Ramamoorthi Ravi
Published: May 2011

Monte Carlo ray tracing of soft shadows produced by area lighting and intricate geometries, such as the shadows through plant leaves or arrays of blockers, is a critical challenge. The final image often has relatively smooth shadow patterns, since it integrates over the light source. However, Monte Carlo rendering exhibits considerable noise even at high sample counts because of the large variance of the integrand due to the intricate shadow function. This article develops an efficient diffuse soft shadow technique for mid to far occluders that relies on a new 4D cache and sheared reconstruction filter. For this, we first derive a frequency analysis of shadows for planar area lights and complex occluders. Our analysis subsumes convolution soft shadows for parallel planes as a special case. It allows us to derive 4D sheared filters that enable lower sampling rates for soft shadows. While previous sheared-reconstruction techniques were able primarily to index samples according to screen position, we need to perform reconstruction at surface receiver points that integrate over vastly different shapes in the reconstruction domain. This is why we develop a new light-field-like 4D data structure to store shadowing values and depth information. Any ray tracing system that shoots shadow rays can easily incorporate our method to greatly reduce sampling rates for diffuse soft shadows.
An efficient scheme for curve and surface construction based on a set of interpolatory basis functions
Authors: Zhang Ren-Jiang , Ma Weiyin
Published: May 2011

An efficient scheme is introduced to construct interpolatory curves and surfaces passing through a set of given scattered data points. The scheme is based on an interpolatory basis derived from the sinc function with a Guassian multiplier previously applied in other fields for signal or function reconstruction. In connection with its application addressed in this article for spatial curve and surface construction, the interpolatory basis possesses various nice properties, such as partition of unity, linear precision, and local support, etc., under a small tolerance. By using these basis functions, free-form curves and surfaces can be conveniently constructed. A designer can adjust the shape of the constructed curve and surface by moving some interpolating points or by inserting new interpolating points. The resulting interpolatory curves and surfaces are
C
∞
continuous. Smooth connection between curves or surfaces can easily be achieved. Closed curves and surfaces can also be expressed using the proposed interpolatory basis functions.
Interactive architectural modeling with procedural extrusions
Authors: Kelly Tom , Wonka Peter
Published: May 2011

We present an interactive procedural modeling system for the exterior of architectural models. Our modeling system is based on procedural extrusions of building footprints. The main novelty of our work is that we can model difficult architectural surfaces in a procedural framework, for example, curved roofs, overhanging roofs, dormer windows, interior dormer windows, roof constructions with vertical walls, buttresses, chimneys, bay windows, columns, pilasters, and alcoves. We present a user interface to interactively specify procedural extrusions, a sweep plane algorithm to compute a two-manifold architectural surface, and applications to architectural modeling.
Frame-based elastic models
Authors: Gilles Benjamin , Bousquet Guillaume , Faure Francois , Pai Dinesh K.
Published: May 2011

We present a new type of deformable model which combines the realism of physically-based continuum mechanics models and the usability of frame-based skinning methods. The degrees of freedom are coordinate frames. In contrast with traditional skinning, frame positions are not scripted but move in reaction to internal body forces. The displacement field is smoothly interpolated using dual quaternion blending. The deformation gradient and its derivatives are computed at each sample point of a deformed object and used in the equations of Lagrangian mechanics to achieve physical realism. This allows easy and very intuitive definition of the degrees of freedom of the deformable object. The meshless discretization allows on-the-fly insertion of frames to create local deformations where needed. We formulate the dynamics of these models in detail and describe some precomputations that can be used for speed. We show that our method is effective for behaviors ranging from simple unimodal deformations to complex realistic deformations comparable with Finite Element simulations. To encourage its use, the software will be freely available in the simulation platform SOFA.
Application-specific service technologies for commodity operating systems in real-time environments
Authors: West Richard , Parmer Gabriel
Published: May 2011

In order to eliminate the costs of proprietary systems and special purpose hardware, many real-time and embedded computing platforms are being built on commodity operating systems and generic hardware. Unfortunately, many such systems are ill-suited to the low-latency and predictable timing requirements of real-time applications. This article, therefore, focuses on application-specific service technologies for low-cost commodity operating systems and hardware, so that real-time service guarantees can be met. We describe contrasting methods to deploy
first-class services
on commodity systems that are dispatched with low latency and execute asynchronously according to bounds on CPU, memory, and I/O device usage. Specifically, we present a “user-level sandboxing” (ULS) mechanism that relies on hardware protection to isolate application-specific services from the core kernel. This approach is compared with a hybrid language and runtime protection scheme, called
SafeX
, that allows untrusted services to be dynamically linked and loaded into a base kernel. SafeX and ULS have been implemented on commodity Linux systems. Experimental results have shown—that both approaches are capable of reducing service violations (and, hence, better qualities of service) for real-time tasks, compared to traditional user-level methods of service deployment in process-private address spaces. ULS imposes minimal additional overheads on service dispatch latency compared to SafeX, with the advantage that it does not require application-specific services to execute in the trusted kernel domain. As evidence of the potential capabilities of ULS, we show how a user-level networking stack can be implemented to avoid data copying via the kernel and allow packet processing without explicit process scheduling. This improves throughput and reduces jitter.
Efficient hardware-based nonintrusive dynamic application profiling
Authors: Nair Ajay , Shankar Karthik , Lysecky Roman
Published: May 2011

Application profiling—the process of monitoring an application to determine the frequency of execution within specific regions—is an essential step within the design process for many software and hardware systems. Profiling is often a critical step within hardware/software partitioning utilized to determine the critical kernels of an application. In this article, we present an innovative, nonintrusive dynamic application profiler (DAProf) capable of profiling an executing application by monitoring the application's short backward branches, function calls, and function returns. The resulting profile information provides an accurate characterization of the frequently executed loops within the application providing a breakdown of loop executions versus loop iterations per execution. DAProf achieves excellent profiling accuracy with an average accuracy of 98% for loop executions, 97% for average iterations per execution, and 95% for percentage of execution time. In addition, the presented dynamic application profiler incurs as little as 11% area overhead compared to an ARM9 microprocessor. DAProf is ideally suited for rapidly profiling software applications and dynamic optimization approaches such as dynamic hardware/software partitioning in which detailed loop execution information is needed to provide accurate performance estimates.
Formal specification and analysis of zeroconf using uppaalS
Authors: Berendsen Jasper , Gebremichael Biniam , Vaandrager Frits W. , Zhang Miaomiao
Published: May 2011

The model checker Uppaal is used to formally model and analyze parts of Zeroconf, a protocol for dynamic configuration of IPv4 link-local addresses that has been defined in RFC 3927 of the IETF. Our goal has been to construct a model that (a) is easy to understand by engineers, (b) comes as close as possible to the informal text (for each transition in the model there should be a corresponding piece of text in the RFC), and (c) may serve as a basis for formal verification. Our modeling efforts revealed several errors (or at least ambiguities) in the RFC that no one else spotted before. We present two proofs of the mutual exclusion property for Zeroconf (for an arbitrary number of hosts and IP addresses): a manual, operational proof, and a proof that combines model checking with the application of a new abstraction relation that is compositional with respect to committed locations. The model checking problem has been solved using Uppaal and the abstractions have been checked by hand.
Evaluating address register assignment and offset assignment algorithms
Authors: Huynh Johnny , Amaral José Nelson , Berube Paul , Touati Sid-Ahmed-Ali
Published: May 2011

In digital signal processors (DSPs), variables are accessed using
k
address registers. The problem of finding a memory layout, for a set of variables, that minimizes the address-computation overhead is known as the General Offset Assignment (GOA) problem. The most common approach to this problem is to partition the set of variables into
k
partitions and to assign each partition to an address register. Thus, effectively decomposing the GOA problem into several Simple Offset Assignment (SOA) problems. Many heuristic-based algorithms are proposed in the literature to approximate solutions to both the variable partitioning and the SOA problems. However, the address-computation overhead of the resulting memory layouts are not accurately evaluated. This article presents an evaluation of memory layouts that uses Gebotys' optimal address-code generation technique. The use of this evaluation method leads to a new optimization problem: the Memory Layout Permutation (MLP) problem. We then use Gebotys' technique and an exhaustive solution to the MLP problem to evaluate heuristic-based offset-assignment algorithms. The memory layouts produced by each algorithm are compared against each other and against the optimal layouts. The results show that even in small access sequences with 12 variables or less, current heuristics may produce memory layouts with address-computation overheads up to two times higher than the overhead of an optimal layout.
Designing mobile interfaces for novice and low-literacy users
Authors: Medhi Indrani , Patnaik Somani , Brunskill Emma , Gautama S.N. Nagasena , Thies William , Toyama Kentaro
Published: May 2011

While mobile phones have found broad application in bringing health, financial, and other services to the developing world, usability remains a major hurdle for novice and low-literacy populations. In this article, we take two steps to evaluate and improve the usability of mobile interfaces for such users. First, we offer an ethnographic study of the usability barriers facing 90 low-literacy subjects in India, Kenya, the Philippines, and South Africa. Then, via two studies involving over 70 subjects in India, we quantitatively compare the usability of different points in the mobile design space. In addition to text interfaces such as electronic forms, SMS, and USSD, we consider three text-free interfaces: a spoken dialog system, a graphical interface, and a live operator.

Our results confirm that textual interfaces are unusable by first-time low-literacy users, and error prone for literate but novice users. In the context of healthcare, we find that a live operator is up to ten times more accurate than text-based interfaces, and can also be cost effective in countries such as India. In the context of mobile banking, we find that task completion is highest with a graphical interface, but those who understand the spoken dialog system can use it more quickly due to their comfort and familiarity with speech. We synthesize our findings into a set of design recommendations.
Refactoring using type constraints
Authors: Tip Frank , Fuhrer Robert M. , Kieżun Adam , Ernst Michael D. , Balaban Ittai , De Sutter Bjorn
Published: May 2011

Type constraints express subtype relationships between the types of program expressions, for example, those relationships that are required for type correctness. Type constraints were originally proposed as a convenient framework for solving type checking and type inference problems. This paper shows how type constraints can be used as the basis for practical refactoring tools. In our approach, a set of type constraints is derived from a type-correct program
P
. The main insight behind our work is the fact that
P
constitutes just one solution to this constraint system, and that alternative solutions may exist that correspond to refactored versions of
P
. We show how a number of refactorings for manipulating types and class hierarchies can be expressed naturally using type constraints. Several refactorings in the standard distribution of Eclipse are based on our work.
Mathematical foundation of trace scheduling
Authors: Banerjee Utpal
Published: May 2011

Since its introduction by Joseph A. Fisher in 1979, trace scheduling has influenced much of the work on compile-time ILP (Instruction Level Parallelism) transformations. Initially developed for use in microcode compaction, it quickly became the main technique for machine-level compile-time parallelism exploitation. Although it has been used since the 1980s in many state-of-the-art compilers (e.g., Intel, Fujitsu, HP), a rigorous theory of trace scheduling is still lacking in the existing literature. This is reflected in the ad hoc way compensation code is inserted after a trace compaction, in the total absence of any attempts to measure the size of that compensation code, and so on.

The aim of this article is to create a mathematical theory of the foundation of trace scheduling. We give a clear algorithm showing how to insert compensation code after a trace is replaced with its schedule, and then
prove
that the resulting program is indeed equivalent to the original program. We derive an upper bound on the size of that compensation code, and show that this bound can be actually attained. We also give a very simple proof that the trace scheduling algorithm always terminates.
Concept-Based Information Retrieval Using Explicit Semantic Analysis
Authors: Egozi Ofer , Markovitch Shaul , Gabrilovich Evgeniy
Published: May 2011

Information retrieval systems traditionally rely on textual keywords to index and retrieve documents. Keyword-based retrieval may return inaccurate and incomplete results when different keywords are used to describe the same concept in the documents and in the queries. Furthermore, the relationship between these related keywords may be semantic rather than syntactic, and capturing it thus requires access to comprehensive human world knowledge. Concept-based retrieval methods have attempted to tackle these difficulties by using manually built thesauri, by relying on term cooccurrence data, or by extracting latent word relationships and concepts from a corpus. In this article we introduce a new concept-based retrieval approach based on Explicit Semantic Analysis (ESA), a recently proposed method that augments keyword-based text representation with concept-based features, automatically extracted from massive human knowledge repositories such as Wikipedia. Our approach generates new text features automatically, and we have found that high-quality feature selection becomes crucial in this setting to make the retrieval more focused. However, due to the lack of labeled data, traditional feature selection methods cannot be used, hence we propose new methods that use self-generated labeled training data. The resulting system is evaluated on several TREC datasets, showing superior performance over previous state-of-the-art results.
Improving Recommender Systems by Incorporating Social Contextual Information
Authors: Ma Hao , Zhou Tom Chao , Lyu Michael R. , King Irwin
Published: May 2011

Due to their potential commercial value and the associated great research challenges,
recommender systems
have been extensively studied by both academia and industry recently. However, the data sparsity problem of the involved user-item matrix seriously affects the recommendation quality. Many existing approaches to recommender systems cannot easily deal with users who have made very few ratings. In view of the exponential growth of information generated by online users, social contextual information analysis is becoming important for many Web applications. In this article, we propose a factor analysis approach based on probabilistic matrix factorization to alleviate the data sparsity and poor prediction accuracy problems by incorporating social contextual information, such as social networks and social tags. The complexity analysis indicates that our approach can be applied to very large datasets since it scales linearly with the number of observations. Moreover, the experimental results show that our method performs much better than the state-of-the-art approaches, especially in the circumstance that users have made few ratings.
Identifying, Indexing, and Ranking Chemical Formulae and Chemical Names in Digital Documents
Authors: Sun Bingjun , Mitra Prasenjit , Lee Giles C. , Mueller Karl T.
Published: May 2011

End-users utilize chemical search engines to search for chemical formulae and chemical names. Chemical search engines identify and index chemical formulae and chemical names appearing in text documents to support efficient search and retrieval in the future. Identifying chemical formulae and chemical names in text automatically has been a hard problem that has met with varying degrees of success in the past. We propose algorithms for chemical formula and chemical name tagging using Conditional Random Fields (CRFs) and Support Vector Machines (SVMs) that achieve higher accuracy than existing (published) methods. After chemical entities have been identified in text documents, they must be indexed. In order to support user-provided search queries that require a partial match between the chemical name segment used as a keyword or a partial chemical formula, all possible (or a significant number of) subformulae of formulae that appear in any document and all possible subterms (e.g., “methyl”) of chemical names (e.g., “methylethyl ketone”) must be indexed. Indexing all possible subformulae and subterms results in an exponential increase in the storage and memory requirements as well as the time taken to process the indices. We propose techniques to prune the indices significantly without reducing the quality of the returned results significantly. Finally, we propose multiple query semantics to allow users to pose different types of partial search queries for chemical entities. We demonstrate empirically that our search engines improve the relevance of the returned results for search queries involving chemical entities.
Building outwards from sustainable HCI
Authors: Huang Elaine M.
Published: May 2011

Sustainability in (Inter)Action provides a forum for innovative thought, design, and research in the area of interaction design and environmental sustainability. The column explores how HCI can contribute to the complex and interdisciplinary efforts to address sustainability challenges.
IT in healthcare
Authors: Mynatt Elizabeth D.
Published: May 2011

This forum is dedicated to personal health in all its many facets: decision-making, goal setting, celebration, discovery, reflection, and coordination --- even entertainment. We'll look at innovations in interactive technologies and how they help address current critical healthcare challenges.
INTERACTING WITH PUBLIC POLICYAre HCI researchers an endangered species in Brazil?
Authors: Junqueira Barbosa Simone Diniz , de Souza Clarisse Sieckenius
Published: May 2011

Public policy increasingly plays a role in influencing the work that we do as HCI researchers, interaction designers, and practitioners. "Public policy" is a broad term that includes both government policy and policy within non-governmental organizations, such as standards bodies. The Interacting with Public Policy forum focuses on topics at the intersection of human-computer interaction and public policy.
TIMELINESThe DigiBarn computer museum
Authors: Damer Bruce
Published: May 2011

Timelines provides perspectives on HCI history, glancing back at a road that sometimes took unexpected branches and turns. History is not a dry list of events; it is about points of view and differing interpretations.
Hyperketonemia increases monocyte adhesion to endothelial cells and is mediated by LFA-1 expression in monocytes and ICAM-1 expression in endothelial cells
Authors: Rains Justin L. , Jain Sushil K.
Published: May 2011

Frequent episodes of hyperketonemia are associated with a higher incidence of vascular disease. The objective of this study was to examine the hypothesis that hyperketonemia increases monocyte-endothelial cell (EC) adhesion and the development of vascular disease in diabetes. Human U937 and THP-1 monocyte cell lines and human umbilical vein endothelial cells (HUVECs) were cultured with acetoacetate (AA) (0–10 mM) or β-hydroxybutyrate (BHB) (0–10 mM) for 24 h prior to evaluating adhesion and adhesion molecule expression. The results demonstrate a significant ( P < 0.01) increase in both U937 and THP-1 adhesion to HUVEC monolayers treated with 4 mM AA compared with control. Equal concentrations of BHB resulted in similar increases in monocyte-EC adhesion. Similarly, treatments of AA or BHB to isolated monocytes from human blood also show increases in adhesion to endothelial cells. intercellular adhesion molecule-1 (ICAM-1) was significantly increased on the surface of HUVECs and an increase in total protein expression with AA treatment compared with control. The expression level of lymphocyte function-associated antigen-1 (LFA-1) was increased in monocytes treated with AA, and LFA-1 affinity was altered from low to high affinity following treatment with both AA and BHB. Monocyte adhesion could be blocked when cells were preincubated with an antibody to ICAM-1 or LFA-1. Results also show a significant increase in IL-8 and MCP-1 secretion in monocytes and HUVECs treated with 0–10 mM AA. These results suggest that hyperketonemia can induce monocyte adhesion to endothelial cells and that it is mediated via increased ICAM-1 expression in endothelial cells and increased expression and affinity of LFA-1 in monocytes.
Left ventricular systolic and diastolic function during tilt-table positioning and passive heat stress in humans
Authors: Nelson Michael D. , Altamirano-Diaz Luis A. , Petersen Stewart R. , DeLorey Darren S. , Stickland Michael K. , Thompson Richard B. , Haykowsky Mark J.
Published: May 2011

The ventricular response to passive heat stress has predominantly been studied in the supine position. It is presently unclear how acute changes in venous return influence ventricular function during heat stress. To address this question, left ventricular (LV) systolic and diastolic function were studied in 17 healthy men (24.3 ± 4.0 yr; mean ± SD), using two-dimensional transthoracic echocardiography with Doppler ultrasound, during tilt-table positioning (supine, 30° head-up tilt, and 30° head-down tilt), under normothermic and passive heat stress (core temperature 0.8 ± 0.1°C above baseline) conditions. The supine heat stress LV volumetric and functional response was consistent with previous reports. Combining head-up tilt with heat stress reduced end-diastolic (25.2 ± 4.1%) and end-systolic (65.4 ± 10.5%) volume from baseline, whereas heart rate (37.7 ± 2.0%), ejection fraction (9.4 ± 2.4%), and LV elastance (37.7 ± 3.6%) increased, and stroke volume (−28.6 ± 9.4%) and early diastolic inflow (−17.5 ± 6.5%) and annular tissue (−35.6 ± 7.0%) velocities were reduced. Combining head-down tilt with heat stress restored end-diastolic volume, whereas LV elastance (16.8 ± 3.2%), ejection fraction (7.2 ± 2.1%), and systolic annular tissue velocities (22.4 ± 5.0%) remained elevated above baseline, and end-systolic volume was reduced (−15.3 ± 3.9%). Stroke volume and the early and late diastolic inflow and annular tissue velocities were unchanged from baseline. This investigation extends previous work by demonstrating increased LV systolic function with heat stress, under varied levels of venous return, and highlights the preload dependency of early diastolic function during passive heat stress.
Sympathetic α3β2-nAChRs mediate cerebral neurogenic nitrergic vasodilation in the swine
Authors: Lee Reggie Hui-Chao , Liu Yi-Qing , Chen Po-Yi , Liu Chin-Hung , Chen Mei-Fang , Lin Hung-Wen , Kuo Jon-Son , Premkumar Louis S. , Lee Tony Jer-Fu
Published: May 2011

The α7-nicotinic ACh receptor (α7-nAChR) on sympathetic neurons innervating basilar arteries of pigs crossed bred between Landrace and Yorkshire (LY) is known to mediate nicotine-induced, β-amyloid (Aβ)-sensitive nitrergic neurogenic vasodilation. Preliminary studies, however, demonstrated that nicotine-induced cerebral vasodilation in pigs crossbred among Landrace, Yorkshire, and Duroc (LYD) was insensitive to Aβ and α-bungarotoxin (α-BGTX). We investigated nAChR subtype on sympathetic neurons innervating LYD basilar arteries. Nicotine-induced relaxation of porcine isolated basilar arteries was examined by tissue bath myography, inward currents on nAChR-expressing oocytes by two-electrode voltage recording, and mRNA and protein expression in the superior cervical ganglion (SCG) and middle cervical ganglion (MCG) by reverse transcription PCR and Western blotting. Nicotine-induced basilar arterial relaxation was not affected by Aβ, α-BGTX, and α-conotoxin IMI (α7-nAChR antagonists), or α-conotoxin AuIB (α3β4-nAChR antagonist) but was inhibited by tropinone and tropane (α3-containing nAChR antagonists) and α-conotoxin MII (selective α3β2-nAChR antagonist). Nicotine-induced inward currents in α3β2-nAChR-expressing oocytes were inhibited by α-conotoxin MII but not by α-BGTX, Aβ, or α-conotoxin AuIB. mRNAs of α3-, α7-, β2-, and β4-subunits were expressed in both SCGs and MCGs with significantly higher mRNAs of α3-, β2-, and β4-subunits than that of α7-subunit. The Aβ-insensitive sympathetic α3β2-nAChR mediates nicotine-induced cerebral nitrergic neurogenic vasodilation in LYD pigs. The different finding from Aβ-sensitive α7-nAChR in basilar arteries of LY pigs may offer a partial explanation for different sensitivities of individuals to Aβ in causing diminished cerebral nitrergic vasodilation in diseases involving Aβ.
Modeling and Analysis of Reentrant Manufacturing Systems: Micro‐ and Macroperspectives
Authors: He Fenglan , Dong Ming , Yang Dong
Published: May 2011

In order to obtain the better analysis of the multiple reentrant manufacturing systems (MRMSs), their modeling and analysis from both micro‐ and macroperspectives are considered. First, this paper presents the discrete event simulation models for MRMS and the corresponding algorithms are developed. In order to describe MRMS more accurately, then a modified continuum model is proposed. This continuum model takes into account the re‐entrant degree of products, and its effectiveness is verified through numerical experiments. Finally, based on the discrete event simulation and the modified continuum models, a numerical example is used to analyze the MRMS. The changes in the WIP levels and outflux are also analyzed in details for multiple re‐entrant supply chain networks. Meanwhile, some interesting observations are discussed.
Estimation of Soil Moisture in an Alpine Catchment with RADARSAT2 Images
Authors: Pasolli L. , Notarnicola C. , Bruzzone L. , Bertoldi G. , Della Chiesa S. , Hell V. , Niedrist G. , Tappeiner U. , Zebisch M. , Del Frate F. , Vaglio Laurin G.
Published: May 2011

Soil moisture retrieval is one of the most challenging problems in the context of biophysical parameter estimation from remotely sensed data. Typically, microwave signals are used thanks to their sensitivity to variations in the water content of soil. However, especially in the Alps, the presence of vegetation and the heterogeneity of topography may significantly affect the microwave signal, thus increasing the complexity of the retrieval. In this paper, the effectiveness of RADARSAT2 SAR images for the estimation of soil moisture in an alpine catchment is investigated. We first carry out a sensitivity analysis of the SAR signal to the moisture content of soil and other target properties (e.g., topography and vegetation). Then we propose a technique for estimating soil moisture based on the Support Vector Regression algorithm and the integration of ancillary data. Preliminary results are discussed both in terms of accuracy over point measurements and effectiveness in handling spatially distributed data.
Complexity on Acute Myeloid Leukemia mRNA Transcript Variant
Authors: Cattani Carlo , Pierro Gaetano
Published: May 2011

This paper deals with the sequence analysis of acute myeloid leukemia mRNA. Six transcript variants of mlf1 mRNA, with more than 2000 bps, are analyzed by focusing on the autocorrelation of each distribution. Through the correlation matrix, some patches and similarities are singled out and commented, with respect to similar distributions. The comparison of Kolmogorov fractal dimension will be also given in order to classify the six variants. The existence of a fractal shape, patterns, and symmetries are discussed as well.
WF10 Stimulates NK Cell Cytotoxicity by Increasing LFA‐1‐Mediated Adhesion to Tumor Cells
Authors: Kühne Louisa , Konstandin Mathias , Samstag Yvonne , Meuer Stefan , Giese Thomas , Watzl Carsten
Published: May 2011

The redox‐active chlorite‐based drug WF10 (Immunokine) was shown to have modulatory effects on both the innate and adaptive immune system in vitro and in vivo. Animal studies suggest that WF10 enhances immunity against tumors. One possible explanation for such an effect is that WF10 stimulates natural killer cell cytotoxicity against malignant cells. Here, we show that WF10 regulates human NK cell cytotoxicity in a time‐dependent manner, following an S‐shaped kinetic with an initial stimulation of activity followed by a decrease in activity relative to the untreated controls. WF10 does not activate NK cells on its own but co‐stimulates NK cell activation mediated by different activating receptors. This is mediated by enhancing NK cell adhesion to target cells through promoting the activation of the integrin LFA‐1. These data demonstrate a direct effect of WF10 on the cytotoxicity of human NK cells.
High-throughput RNAi Screening Identifies a Role for TNK1 in Growth and Survival of Pancreatic Cancer Cells
Authors: Henderson Meredith C. , Gonzales Irma M. , Arora Shilpi , Choudhary Ashish , Trent Jeffrey M. , Von Hoff Daniel D. , Mousses Spyro , Azorsa David O.
Published: May 2011

To identify novel targets in pancreatic cancer cells, we used high-throughput RNAi (HT-RNAi) to select genes that, when silenced, would decrease viability of pancreatic cancer cells. The HT-RNAi screen involved reverse transfecting the pancreatic cancer cell line BxPC3 with a siRNA library targeting 572 kinases. From replicate screens, approximately 32 kinases were designated as hits, of which 22 kinase targets were selected for confirmation and validation. One kinase identified as a hit from this screen was tyrosine kinase nonreceptor 1 (TNK1), a kinase previously identified as having tumor suppressor-like properties in embryonic stem cells. Silencing of TNK1 with siRNA showed reduced proliferation in a panel of pancreatic cancer cell lines. Furthermore, we showed that silencing of TNK1 led to increased apoptosis through a caspase-dependent pathway and that targeting TNK1 with siRNA can synergize with gemcitabine treatment. Despite previous reports that TNK1 affects Ras and NF-κB signaling, we did not find similar correlations with these pathways in pancreatic cancer cells. Our results suggest that TNK1 in pancreatic cancer cells does not possess the same tumor suppressor properties seen in embryonic cells but seems to be involved in growth and survival. The application of functional genomics by using HT-RNAi screens has allowed us to identify TNK1 as a growth-associated kinase in pancreatic cancer cells. Mol Cancer Res; 9(6); 724–32. ©2011 AACR.
Tumor Thrombectomy via a Surgically Reopened Umbilical Vein Combined with Right Hemihepatectomy in a Patient with Hepatocellular Carcinoma
Authors: Soyama Akihiko , Eguchi Susumu , Takatsuki Mitsuhisa , Hidaka Masaaki , Muraoka Izumi , Tomonaga Tetsuo , Kanematsu Takashi
Published: May 2011

This report presents a case of a patient with a huge hepatocellular carcinoma in the right lobe of the liver with an extensive portal venous tumor thrombus extending into the main portal trunk and left portal branch. The patient underwent extended right hemihepatectomy with tumor thrombectomy with direct extraction from an opening of the ventral wall of the right portal vein and using a balloon catheter to push the tumor thrombus via the surgically reopened umbilical vein. This technique seems useful in cases of tumor thrombus that extend deep into the umbilical portion of the left portal vein. In addition, this technique may have minimized the intraoperative migration of the tumor thrombus into the future remnant liver by occluding portal flow with the balloon catheter during the thrombectomy.
A Novel SRD5A2 Mutation with Loss of Function Identified in Chinese Patients with Hypospadias
Authors: Zhang Manna , Yang Jun , Zhang Huijie , Ning Guang , Li Xiaoying , Sun Shouyue
Published: May 2011

Objective: To investigate the functional change of SRD5A2 gene mutations identified in patients with 5α-reductase type 2 deficiency. Patients and Methods: Three unrelated subjects born with ambiguous genitalia were included. All patients were initially reared as girls, but they gradually exhibited variable degrees of virilization at puberty without breast development, followed by a change of gender role. Sequencing analysis of the SRD5A2 gene was performed and enzymatic activities of 5α-reductase type 2 were assessed. Results: Three compound heterozygous mutations in the SRD5A2 gene were identified: patient 1 with p.G203S/ c.655delT, patient 2 with p.Q6X/p.G203S, and patient 3 with p.G203S/c.755_756insT. Heterozygosity for the p.V89L polymorphism was also found in patients 2 and 3. The c.655delT mutation led to a complete loss of the enzymatic activity, whereas mutants p.G203S and c.755_756insT resulted in a reduction of the enzymatic activities by 60 and 90%, respectively. Conclusion: Two frameshift heterozygous mutations, c.655delT and c.755_756insT, led to a dramatic reduction in 5α-reductase activity, and the latter had not been reported previously. In addition, the heterozygous mutation (p.G203) identified in the 3 patients presumably suggests a founder effect in the Chinese population and may explain the similarity in phenotype among the patients.
Ruptured Brain Arteriovenous Malformations in Children: Correlation of Clinical Outcome with Admission Parameters
Authors: Wong Sui-To , Fong Dawson
Published: May 2011

Aims: To gain a better understanding of how clinical outcome in children with ruptured brain arteriovenous malformations (bAVMs) correlates with clinical and imaging parameters on admission. Methods: The authors retrospectively reviewed patients with bAVMs, aged 18 or below, managed at their hospital between January 1992 and December 2008. Clinical outcome was assessed using the modified Rankin Scale (mRS). Patients with ruptured bAVMs were analyzed; their clinical parameters and computerized tomography findings on admission were recorded. Clinical outcome was then evaluated against admission scores using the Glasgow Coma Scale (GCS), the World Federation of Neurosurgical Societies Grading System of Subarachnoid Hemorrhage (WFNS-SAH), the Spetzler-Martin grade, the intracerebral hemorrhage score and 2 other independent parameters, namely pupillary response and significant focal neurological injuries. Spearman’s correlation coefficient, linear regression analysis and multivariate logistic regression analysis were used for data analysis. Results: 40 pediatric patients with bAVMs were found and 32 of them presented with hemorrhage (80%). In the 32 children with ruptured bAVMS, follow-up ranged between 7 and 204 months (median 100.5 months). The complete excision/obliteration rate as confirmed by digital subtraction angiography was 73.3%. The mRS scores at the last follow-up were: grades 0–II in 87.5%; grades IV–V in 6.25%, and grade VI in 6.25%. The Spetzler-Martin grade, the intracerebral hemorrhage score, the WFNS-SAH grade, the GCS scores, and a combined scoring scale consisting of the GCS, pupillary response and significant focal neurological injuries correlated significantly with clinical outcome 6 months after hemorrhage. However, on the scatter diagrams, it appeared that only the combined scoring scale might be valid for clinical practice. Multivariate logistic regression analysis showed that the combined scoring scale was a statistically significant independent predictor of clinical outcome 6 months after hemorrhage. Conclusion: In this series of pediatric patients with ruptured bAVMs, although various grading scales correlated significantly with clinical outcome 6 months after hemorrhage, only the combined scoring scale might have the potential to be applied to predict clinical outcome in these children.
Endoscopic Third Ventriculostomy in Obstructive Infantile Hydrocephalus: Remarks about the So-Called ‘Unsuccessful Cases’
Authors: Gallo Pasquale , Szathmari Alexandru , De Biasi Sara , Mottolese Carmine
Published: May 2011

Background: The failure rate following endoscopic third ventriculostomy (ETV) in infants younger than 2 years of age has been reported to be higher compared with that of older children, and it is unclear whether ETV might be superior to shunt placement in this age group. Methods: Between 2003 and 2009, 23 patients younger than 6 months and without a previous history of shunting underwent ETV in our institution. A review of the literature was performed on the basis of publications presenting detailed data on age and etiology in every single patient. Results: In our own patients, total success rate was 39.1%. In the successful cases, median age was 140 days, whereas in the unsuccessful cases it was 47 days. The difference between the two groups was statistically significant (p = 0.01). The median ages of both successful and unsuccessful groups corresponded to data gained from an analysis of the literature (p = 0.04). At a median follow-up of 47 months, 2 out of 14 patients shunted after a failed ETV were revised for ventriculoperitoneal shunt malfunction. Conclusion: The impact of age on ETV failure in infants is clear and becomes crucial during the first 2 months of life, even when excluding etiological factors. Nevertheless, age cannot be considered the only parameter of the decision-making process, especially in these very young patients. Probably, the definition of ‘unsuccessful ETV’ should be reevaluated in light of decreased risk of shunt malfunction observed after a failed ETV.
Ethnic, Racial and Cultural Identity and Perceived Benefits and Barriers Related to Genetic Testing for Breast Cancer among At-Risk Women of African Descent in New York City
Authors: Sussner K.M. , Edwards T.A. , Thompson H.S. , Jandorf L. , Kwate N.O. , Forman A. , Brown K. , Kapil-Pair N. , Bovbjerg D.H. , Schwartz M.D. , Valdimarsdottir H.B.
Published: May 2011

Background: Due to disparities in the use of genetic services, there has been growing interest in examining beliefs and attitudes related to genetic testing for breast and/or ovarian cancer risk among women of African descent. However, to date, few studies have addressed critical cultural variations among this minority group and their influence on such beliefs and attitudes. Methods: We assessed ethnic, racial and cultural identity and examined their relationships with perceived benefits and barriers related to genetic testing for cancer risk in a sample of 160 women of African descent (49% self-identified African American, 39% Black-West Indian/Caribbean, 12% Black-Other) who met genetic risk criteria and were participating in a larger longitudinal study including the opportunity for free genetic counseling and testing in New York City. All participants completed the following previously validated measures: (a) the multi-group ethnic identity measure (including ethnic search and affirmation subscales) and other-group orientation for ethnic identity, (b) centrality to assess racial identity, and (c) Africentrism to measure cultural identity. Perceived benefits and barriers related to genetic testing included: (1) pros/advantages (including family-related pros), (2) cons/disadvantages (including family-related cons, stigma and confidentiality concerns), and (3) concerns about abuses of genetic testing. Results: In multivariate analyses, several ethnic identity elements showed significant, largely positive relationships to perceived benefits about genetic testing for breast and/or ovarian cancer risk, the exception being ethnic search, which was positively associated with cons/disadvantages, in general, and family-related cons/disadvantages. Racial identity (centrality) showed a significant association with confidentiality concerns. Cultural identity (Africentrism) was not related to perceived benefits and/or barriers. Conclusions: Ethnic and racial identity may influence perceived benefits and barriers related to genetic testing for breast and/or ovarian cancer risk among at-risk women of African descent. Genetic counseling services may want to take into account these factors in the creation of culturally-appropriate services which best meet the needs of this heterogenous population.
Brugada Type 1 Electrocardiographic Pattern Induced by Severe Hyponatremia
Authors: Alvarez Paulino A. , Vázquez Blanco Manuel , Lerman Jorge
Published: May 2011

Brugada syndrome is characterized electrocardiographically by ST segment elevation in the right precordial leads, followed by a negative T wave unrelated to ischemia, electrolyte disturbance or drug effects and prone to rapid polymorphic ventricular tachycardia capable of degenerating into ventricular fibrillation. The ECG pattern may be dynamic and is often concealed. Sodium channel blockers, drugs, electrolyte imbalances, fever and several other clinical circumstances are recognized inducers of a Brugada type 1 ECG in susceptible patients. We describe a case of a Brugada type 1 ECG pattern induced by severe hyponatremia.
Cerebral Anomalies and Chiari Type 1 Malformation
Authors: Galarza Marcelo , Martínez-Lage Juan F. , Ham Steven , Sood Sandeep
Published: May 2011

Objective: To analyze the association of diverse cerebral anomalies in a series of pediatric patients with cerebellar tonsillar ectopia. Methods: We reviewed the medical records of 60 children diagnosed with Chiari type 1 malformation (CM1), of these, 20 patients (11 boys and 9 girls; mean age 7.2 years, range 2–16 years) had an associated cerebral anomaly. Symptoms of tonsillar ectopia evolved over a mean of 12 months (range 3 months to 4 years). Syringomyelia was present in 5 cases. All patients underwent a posterior fossa decompression. Results: Disclosed anomalies included: congenital hydrocephalus (n = 11), cervicomedullary kinking (n = 5), focal cerebral heterotopia with epilepsy (n = 4), partial agenesis of the corpus callosum (n = 4), hypoplastic brain stem (n = 2), holoprosencephaly (n = 1), and subcortical dysplasia in the context of neurofibromatosis type 1 (n = 1). Other malformations included: subcortical hamartoma associated with neurofibromatosis type 1, craniofacial dysmorphism secondary to Noonan syndrome, congenital occipital plagiocephaly, os odontoideum, craniofacial cleft, juvenile rheumathoid arthritis with platybasia, and osteogenesis imperfecta with bathrocephaly and scoliosis. Conclusion: Craniocerebral anomalies in children treated for CM1 may be found consistently. The association of hydrocephalus, which was the most common anomaly in this cohort, with cerebellar tonsillar ectopia may contribute to a poor outcome in regard to tonsillar herniation symptoms.