bluuebunny/crossref_metadata_2025 huggingface dataset:
Residues Arg283, Arg285, and Ile287 in the Nucleotide Binding Pocket of Bovine Viral Diarrhea Virus NS5B RNA Polymerase Affect Catalysis and Fidelity
Authors: Curti Elena , Jaeger Joachim
Published: October 2012

Residues Arg283, Arg285, and Ile287 are highly conserved amino acids in bovine viral diarrhea virus RNA polymerase (BVDV RdRp) and RdRps from related positive-strand RNA viruses. This motif is an important part of the binding pocket for the nascent RNA base pair during initiation and elongation. We found that replacement of the arginines with alanines or more conserved lysines or replacement of isoleucine with alanine or valine alters the ability of the mutant RdRps to incorporate ribonucleotides efficiently. The reduced RdRp activity stems from both decreased ribonucleotide binding and decreased catalytic efficiency in both primer-dependent and
de novo
initiation, as shown by kinetic studies. In line with other studies on flaviviral RdRps, our data suggest that Arg283 and Ile287 may be implicated in ribonucleotide binding and positioning of the template base in the active site. Arg285 appears to be involved directly in the selection of cognate nucleotide. The findings for Arg285 and Ile287 mutants also agree with similar data from picornavirus RdRps.
HETEROGENEOUS ASPIRATIONS PROMOTE COOPERATION IN THE PUBLIC GOODS GAME
Authors: SUN LEI , YANG HAN-XIN , CHEN SHAO-MIN , CHEN YA-SHAN
Published: October 2012

We study the impact of heterogeneous aspirations on the spatial public goods game (PGG) in a square lattice. An aspiration parameter u is introduced to decide who will be more probably to become the potential strategy source in structured population. Individuals are divided into two groups A(u > 0) and B(u = 0) by fraction v and 1 - v. We study how u and v affect cooperation in the PGG. For low values of u, the cooperation level monotonously increases as v increases. However, for large values of u, there exist an intermediate v ≈ 0.5 for which cooperation thrives best. The influence of noise is also investigated. We find that the highest threshold of phase transition is reached at the middle value of noise.
PREDICTION OF CONVECTIVE HEAT TRANSFER OF NANOFLUIDS BASED ON FRACTAL-MONTE CARLO SIMULATIONS
Authors: XIAO BO-QI , JIANG GUO-PING , YANG YI , ZHENG DONG-MEI
Published: October 2012

With the consideration of the Brownian motion of nanoparticles in fluids, the probability model for the size of nanoparticles and the model for convective heat transfer of nanofluids are derived based on the fractal character of nanoparticles. The proposed model is expressed as a function of the size of nanoparticles, the volumetric nanoparticle concentration, the thermal conductivity of base fluids, fractal dimension of nanoparticles and the temperature, as well as the random number. It is found that the convective heat flux of nanofluids decreases with increasing of the average diameter of nanoparticles. This model has the characters of both analytical and numerical solutions. The Monte Carlo simulations combined with the fractal geometry theory are performed. Every parameter of the proposed formula on convective heat transfer of nanofluids has clear physical meaning. So the proposed model can reveal the physical mechanisms of convective heat transfer of nanofluids.
EXPLICIT MODEL REALIZING PARTON–HADRON DUALITY
Authors: JENKOVSZKY LÁSZLÓ L. , MAGAS VOLODYMYR K. , LONDERGAN J. TIMOTHY , SZCZEPANIAK ADAM P.
Published: October 2012

We present a model that realizes both resonance-Regge (Veneziano) and parton–hadron (Bloom–Gilman) duality. We first review the features of the Veneziano model and we discuss how parton–hadron duality appears in the Bloom–Gilman model. Then we review limitations of the Veneziano model, namely that the zero-width resonances in the Veneziano model violate unitarity and Mandelstam analyticity. We discuss how such problems are alleviated in models that construct dual amplitudes with Mandelstam analyticity (so-called DAMA models). We then introduce a modified DAMA model, and we discuss its properties. We present a pedagogical model for dual amplitudes and we construct the nucleon structure function F2(x, Q2). We explicitly show that the resulting structure function realizes both Veneziano and Bloom–Gilman duality.
SIGNS AND COSMOLOGY
Authors: DASGUPTA ARUNDHATI , ZAMPELI ADAMANTIA
Published: October 2012

Using a new effective action predicted from quantum gravity where the sign of the Euclidean Einstein action is reversed, we discuss Wentzel–Kramers–Brillouin (WKB) solutions in quantum cosmology and predict that this sign change might explain the origin of phantom scalars.
TYPICAL BEHAVIOR OF THE GLOBAL ENTANGLEMENT OF AN OPEN MULTIQUBIT SYSTEM IN A NON-MARKOVIAN REGIMEN
Authors: MAJTEY A. P. , PLASTINO A. R.
Published: October 2012

We investigate the decay of the global entanglement, due to decoherence, of multiqubit systems interacting with a reservoir in a non-Markovian regime. We assume that during the decoherence process each qubit of the system interacts with its own, independent environment. Most previous works on this problem focused on particular initial states or families of initial states amenable of analytical treatment. Here we determine numerically the typical, average behavior of the system corresponding to random initial pure states uniformly distributed (in the whole Hilbert space of n-qubit pure states) according to the Haar measure. We study systems consisting of 3, 4, 5, and 6 qubits. In each case we consider also the entanglement dynamics corresponding to important particular initial states, such as the GHZ states or multiqubit states maximizing the global entanglement, and determine in which cases any of these states is representative of the average behavior associated with general initial states.
THE MODIFICATION OF THE ENERGY SPECTRUM OF CHARGED PARTICLES BY EXOTIC OPEN 4-SMOOTHNESS VIA SUPERSTRING THEORY
Authors: ASSELMEYER-MALUGA TORSTEN , GUSIN PAWEŁ , KRÓL JERZY
Published: October 2012

In this paper we present a model where the modified Landau-like levels of charged particles in a magnetic field are determined due to the modified smoothness of ℝ4 as underlying structure of the Minkowski spacetime. The standard smoothness of ℝ4 is shifted to the exotic [Formula: see text], k = 2p, p = 1, 2, …. This is achieved by superstring theory using gravitational backreaction induced from a strong, almost constant magnetic field on standard ℝ4. The exact string background containing flat ℝ4 is replaced consistently by the curved geometry of SU (2)k × ℝ as part of the modified exact backgrounds. This corresponds to the change of smoothness on ℝ4 from the standard ℝ4 to some exotic [Formula: see text]. The calculations of the spectra are using the CFT marginal deformations and Wess–Zumino–Witten (WZW) models. The marginal deformations capture the effects of the magnetic field as well as its gravitational backreactions. The spectra depend on even level k of WZW on SU(2). At the same time the WZ term as element of H3( SU (2), ℝ) determines also the exotic smooth [Formula: see text]. As the consequence we obtain that a nonzero mass-gap induced by the exotic [Formula: see text] emerges in the spectrum.
Carbonate rocks and petroleum reservoirs: a geological perspective from the industry
Authors: Burchette Trevor P.
Published: October 2012

Carbonate oil reservoirs are sometimes regarded with apprehension in the petroleum industry since it can be difficult to predict the quality of, and ensure high recovery factors from, this rock family. Particular problems are the complex and heterogeneous nature of porosity in carbonate rocks, often leading to large ranges in permeability for any given porosity, and the organization of carbonate successions most commonly as vertically heterogeneous, but laterally persistent, layers.

Important issues that arise time and again in carbonate reservoir description include (a) predicting reservoir quality at inter-well scales and in uncored wells, (b) recognizing problematic high-permeability layers, (c) determining the permeability component to allocate to fractures and connected vug systems, and (d) populating reservoir models with representative physical parameters. Because porosity in carbonate rocks generally presents as diverse and heterogeneous, conventional core plugs are seldom representative of large rock volumes and significant issues remain in terms of the scale-compatibility of the various datasets for measured physical parameters that are used in carbonate reservoir description.

Many of the world's largest carbonate reservoirs were discovered and developed shortly after the Second World War and are now showing signs of maturity, expressed variously as poor pressure support, water or gas breakthrough and stranded resources. The proportion of the world's ‘conventional’ petroleum that is reservoired in carbonate rocks is commonly estimated at around 50–60% and many large carbonate reservoirs are likely to have a production lifetime beyond 50 years. It is no coincidence then that the petroleum industry has been the primary source of funding of and promotion of research into carbonate rocks and depositional systems, often with impacts extending well beyond oil and gas exploitation.
The Machar Oil Field, UK Central North Sea: impact of seismic reprocessing on the development of a complex fractured chalk field
Authors: Ward M. V. , Pearse C. , Jehanno Y. , O'Hanlon M. , Zett A. , Houliston D.
Published: October 2012

The Machar Field in the UK Central North Sea is a fractured Cretaceous chalk and Palaeocene sandstone oil reservoir, developed around a tall salt diapir. Machar was discovered in 1976 and, after a lengthy appraisal including extended flow tests starting in 1994, has been developed in a phased manner from 1998 through a multi-well subsea development. The steeper eastern flank has historically lacked coherent reflectivity on seismic data and has remained undrilled. The geological possibility of a reservoir on the east flank provided motivation for extensive seismic reprocessing between 2005 and 2007, and the seismic interpretation showed both a chalk and a sand presence in this area of the field. Simulation modelling suggested that a well here would deliver substantial incremental field volumes. Confidence in the new seismic interpretation reduced the subsurface risk associated with the area, and a new subsea drill-centre reduced the drilling risks and costs sufficiently to allow a Machar East well to be sanctioned. Successful well results in 2008 changed the entire perception of the field and acted as a springboard for further development including a sidetrack in the northern area and a third injection well to support the east, which was drilled and completed in the summer of 2010.
MCEmu
Authors: Tu Chia-Heng , Hung Shih-Hao , Tsai Tung-Chieh
Published: October 2012

Developing software for heterogeneous multicore systems is particularly challenging even for experienced developers. While emulators have proven useful to application development, very few heterogeneous multicore emulators have been made available by vendors so far, as building an emulator for a heterogeneous multicore system has been a time-consuming and difficult task. Thus, we proposed a framework, called MCEmu, to speed up the process of building a heterogeneous multicore emulator by integrating existing and/or new processor emulators. MCEmu is designed to help system and application development, with a basic multicore board support package, an interprocessor communication library, and tools for debugging, tracing, and performance monitoring. In addition, MCEmu can run on a multicore host system to accelerate the emulation of data parallel applications. We show that MCEmu can be very useful for developing system software before the system becomes available, as it has helped us catch numerous functional and performance bugs which could have been hard to find. In this article, we present the design of MCEmu and demonstrate its capabilities with our case studies.
Synchronizing AMS Assertions with AMS Simulation
Authors: Mukherjee Subhankar , Dasgupta Pallab , Mukhopadhyay Siddhartha , Little Scott , Havlicek John , Chandrasekaran Srikanth
Published: October 2012

The verification community anticipates the adoption of assertions in the Analog and Mixed-Signal (AMS) domain in the near future. Several questions need to be answered before AMS assertions are brought into practice, such as: (a) How will the languages for AMS assertions be different from the ones in the digital domain? (b) Does the analog simulator have to be assertion aware? (c) If so, then how and where on the time line will the AMS assertion checker synchronize with the analog simulator? and (d) What will be the performance penalty for monitoring AMS assertions accurately over analog simulation? This article attempts to answer these questions through theoretical analysis and empirical results obtained from industrial test cases. We study logics which extend Linear Temporal Logic (LTL) with predicates over real variables, and show that further extensions allowing the binding of real-valued variables across time makes the logic undecidable. We present a toolkit which can integrate with existing AMS simulators for checking AMS assertions on practical designs. We study the problem of synchronizing the AMS simulator with the AMS assertion checker and demonstrate the performance penalty of different synchronization options.
Resource Sharing of Pipelined Custom Hardware Extension for Energy-Efficient Application-Specific Instruction Set Processor Design
Authors: Lin Hai , Fei Yunsi
Published: October 2012

Application-Specific Instruction set Processor (ASIP) has become an increasingly popular platform for embedded systems because of its high performance, flexibility, and short turn-around time. The hardware extension in ASIPs can speed-up program execution. However, it also incurs area overhead and extra static energy consumption. Traditional datapath merging techniques reduce the circuit overhead by reusing hardware modules for executing multiple operations. However, they introduce structural hazard for multiple custom instructions in sequence, and hence reduce the performance improvement. In this article, we introduce a pipelined configurable structure for the hardware extension in ASIPs, so that structural hazards can be remedied. With multiple subgraphs of operations selected, we design a novel operation-to-hardware mapping algorithm based on Integer Linear Programming (ILP) to automatically construct a resource-efficient pipelined configurable functional unit. Different resource sharing schemes would affect both the hardware overhead and the overall performance improvement. We analyze the design trade-offs between resource efficiency and performance improvement. At the end, we present our design space exploration results by setting the optimization objective to area, area and delay, and delay respectively.
A Hardware/Software Cooperative Custom Register Binding Approach for Register Spill Elimination in Application-Specific Instruction Set Processors
Authors: Lin Hai , Hu Tiansi , Fei Yunsi
Published: October 2012

Application-Specific Instruction set Processor (ASIP) has become an important design choice for embedded systems. It can achieve both high flexibility offered by the base processor core and high performance and energy efficiency offered by the dedicated hardware extensions. Although a lot of efforts have been devoted to computation acceleration, for example, automatic custom instruction identification and synthesis, limited on-chip data storage elements including the register file and data cache have become a potential performance bottleneck. For custom instructions that have more inputs and/or outputs than the generic register file I/O ports, custom registers are added in ASIPs to satisfy the need of additional inputs and outputs, and traditionally they are used only by custom instructions. In this article, we propose a hardware/software cooperative approach with a linear scan register allocation algorithm, which allows base instructions to utilize the existing custom registers in ASIPs for eliminating register spills of the program. The data traffic between the base processor and off-chip memory can be replaced with energy-efficient on-chip communications between the processor core and custom hardware extensions. Our experimental results demonstrate that a significant performance gain can be achieved, orthogonal to improvements by other techniques in ASIP design.
Synthesis of Adaptable Hybrid Adders for Area Optimization under Timing Constraint
Authors: Kim Yonghwan , Kwak Sanghoon , Kim Taewhan
Published: October 2012

Satisfying the timing constraint is the utmost concern in the integrated circuit design and it is true that most critical timing paths in a circuit cover one or more arithmetic components such as adder, subtractor, and multiplier of which addition logic is commonly involved. This work addresses the problem of redesigning the addition logic (in a form of hybrid adder) on a critical timing path to meet the timing constraint while minimally allocating the required addition logic. Unlike the conventional hybrid adder design schemes in which they assume uniform or specific patterns of input signal arrival times and minimize the latest timing of the output signals, our work extracts the required timing of each output signal as well as the input arrival times directly from the circuit and resynthesizes the addition logic by creating a customized hybrid adder that is best suited, in terms of logic area, for meeting the timing constraint of the circuit. Specifically, we propose a systematic approach of hybrid adder design exploration, basically following the principle of dynamic programming with well-controlled pruning techniques. This work is realistic and practically very useful in that it can be used as a timing optimizer to the computation-intensive circuits with a tight timing budget. We provide a set of diverse experimental data to show how much the proposed hybrid adder scheme is effective in meeting or reducing timing while maintaining the circuit area as minimal as possible.
The Synthesis of Cyclic Dependencies with Boolean Satisfiability
Authors: Backes John D. , Riedel Marc D.
Published: October 2012

The accepted wisdom is that combinational circuits must have
acyclic
(i.e., feed-forward) topologies. Yet simple examples suggest that this is incorrect. In fact, introducing cycles (i.e., feedback) into combinational designs can lead to significant savings in area and in delay. Prior work described methodologies for synthesizing cyclic circuits with Sum-Of-Product (SOP) and Binary-Decision Diagram (BDD)-based formulations. Recently, techniques for
analyzing
and
mapping
cyclic circuits based on Boolean satisfiability (SAT) were proposed. This article presents a SAT-based methodology for
synthesizing
cyclic dependencies. The strategy is to generate cyclic functional dependencies through a technique called Craig interpolation. Given a choice of different functional dependencies, a branch-and-bound search is performed to pick the best one. Experiments on benchmark circuits demonstrate the effectiveness of the approach.
Static NBTI Reduction Using Internal Node Control
Authors: Bild David R. , Dick Robert P. , Bok Gregory E.
Published: October 2012

Negative Bias Temperature Instability (NBTI) is a significant reliability concern for nanoscale CMOS circuits. Its effects on circuit timing can be especially pronounced for circuits with standby-mode equipped functional units, because these units can be subjected to static NBTI stress for extended periods of time. This article describes Internal Node Control (INC), in which the inputs to some individual gates are directly manipulated to prevent this static NBTI fatigue. We prove that the INC selection problem is
NP
-complete and present a linear-time heuristic that can quickly determine near-optimal placements. This near-optimality is confirmed by comparing results for small benchmarks against optimal solutions from a mixed integer linear programming formulation of our problem. We evaluate the heuristic on the ISCAS85 benchmarks and the Synopsys DesignWare Library. Our heuristic reduces static NBTI-induced delay over a ten year period by 30--60% and can reduce total path delay by an average 9.4% when NBTI degradation is severe. The INC placements and sleep signal routing require only a 1.6% increase in area.
Launch-on-Shift Test Generation for Testing Scan Designs Containing Synchronous and Asynchronous Clock Domains
Authors: Wu Shianling , Wang Laung-Terng , Wen Xiaoqing , Jone Wen-Ben , Hsiao Michael S. , Li Fangfang , Li James Chien-Mo , Huang Jiun-Lang
Published: October 2012

This article presents a hybrid Automatic Test Pattern Generation (ATPG) technique using the staggered Launch-On-Shift (LOS) scheme followed by the one-hot launch-on-shift scheme for testing delay faults in a scan design containing asynchronous clock domains. Typically, the staggered scheme produces small test sets but needs long ATPG runtime, whereas the one-hot scheme takes short ATPG runtime but yields large test sets. The proposed hybrid technique is intended to reduce test pattern count with acceptable ATPG runtime for multimillion-gate scan designs. In case the scan design contains multiple synchronous clock domains, and each group of synchronous clock domains is treated as a clock group and tested using a launch-aligned or a capture-aligned LOS scheme. By combining these schemes together, we found the pattern counts for two large industrial designs were reduced by approximately 1.6X to 1.8X, while the ATPG runtime was increased by 40% to 50%, when compared to the one-hot clocking scheme alone.
ECR
Authors: Lam Tak-Kei , Tang Wai-Chung , Yang Xiaoqing , Wu Yu-Liang
Published: October 2012

Rewiring is known to be a class of logic restructuring technique that is at least equally powerful in flexibility compared to other logic transformation techniques. Especially it is wiring sensitive and is particularly useful for interconnect-based circuit synthesis processes. One of the most well-studied rewiring techniques is the ATPG-based Redundancy Addition and Removal (RAR) technique which adds a redundant alternative wire to make an originally irredundant target wire become redundant and thus removable. In this article, we propose a new Error-Cancellation-based Rewiring scheme (ECR) which can also identify non-RAR-based rewiring operations with high efficiency. In ECR scheme, it is not necessary for alternative wires to be redundant. Based on the notion of error cancellation, we analyze and reformulate the rewiring problem, and a more generalized rewiring scheme is developed to detect more rewiring cases which are not obtainable by existing schemes while it still maintains a low runtime complexity. Comparing with the most recent non-RAR rewiring tool IRRA, the total number of alternative wires found by our approach is about doubled (202%) while the CPU time used is just slightly more (8%) upon benchmarks preoptimized by ABC’s rewriting. Our experimental results also suggest that the ECR engine is more powerful than IRRA in FPGA technology mapping.
Asymmetric Cache Coherency
Authors: Shield John , Diguet Jean-Philippe , Gogniat Guy
Published: October 2012

Asymmetric coherency is a new optimization method for coherency policies to support nonuniform workloads in multicore processors. Asymmetric coherency assists in load balancing a workload and this is applicable to SoC multicores where the applications are not evenly spread among the processors and customization of the coherency is possible. Asymmetric coherency is a policy change, and consequently our designs require little or no additional hardware over an existing system. We explore two different types of asymmetric coherency policies. Our bus-based asymmetric coherency policy, generated a 60% coherency cost reduction (reduction of latencies due to coherency messages) for nonshared data. Our directory-based asymmetric coherency policy, showed up to a 5.8% execution time improvement and up to a 22% improvement in average memory latency for the parallel benchmarks Sha, using a statically allocated asymmetry. Dynamically allocated asymmetry was found to generate further improvements in access latency, increasing the effectiveness of asymmetric coherency by up to 73.8% when compared to the static asymmetric solution.
Remote FPGA Lab for Enhancing Learning of Digital Systems
Authors: Morgan Fearghal , Cawley Seamus , Newell David
Published: October 2012

Learning in digital systems can be enhanced through applying a learn-by-doing approach on practical hardware systems and by using Web-based technology to visualize and animate hardware behavior. The authors have reported the Web-based Remote FPGA Lab (RFL) which provides a novel, real-time control and visualization interface to a remote, always-on FPGA hardware implementation. The RFL helps students to understand and reason about digital systems operation, using interactive animation of signal behavior in an executing digital logic system, at any level of the design hierarchy. The RFL supports the creation of real-time interactive digital systems teaching demos. The article presents student RFL usage data and survey data which highlight improved student engagement, learning and achievement. The article describes the RFL architecture, communication interface, Web page functionality, user access administration and database management. The article also describes the RFLGen program, developed to automate user design integration into the Xilinx ISE VHDL-based RFL project wrapper for creation of FPGA configuration bitstreams and RFL animations.
Process-oriented application systems for mobile services
Authors: Breitschwerdt Rüdiger , Reinke Philipp , Sextro Markus Kleine , Thomas Oliver
Published: October 2012

A growing number of rescue operations as well as people in need of care cause an increase in ambulant healthcare services. At the same time, the dedicated service providers have to cope with budgets and a decreasing number of qualified personnel. Nevertheless, a high quality of treatment is mandatory. This means a need for improvement enabling the service providers to keep their care processes competitive. Whereas in hospitals, evidence-based guidelines and care pathways have become usual or mandatory, efforts to establish them in ambulant domains are still at an early stage. In contrast to inpatient workflows, standards or best practices have not been established yet. The article analyzes the staffs' intention to use such IT-based support by means of empirical surveys among 444 participants from two fields of application. For this purpose, prospective users would employ applications installed on portable devices -- a potential hardly been considered yet for healthcare service support.
Towards the integration of near-patient collection of information for the delivery of healthcare services
Authors: Briggs Jim , Curry Richard
Published: October 2012

This paper discusses the role that information, particularly information collected and used near to the patient, can play in the delivery of healthcare services. We define what we mean by "near the patient" and review many of the ways in which information is currently collected, stored and shared. We identify what technological and other factors have changed that make the collection and use of information near the patient more likely. We go on to present two scenarios and discuss the opportunities and issues that arise from them.
ACM SIGHIT International Health Informatics Symposium report
Authors: Yang Christopher C.
Published: October 2012

This report summarizes the events and activities of the 2
nd
ACM SIGHIT International Health Informatics Symposium (IHI 2012), which was held in Miami, Florida, January 28-30, 2012. IHI 2012 is the flagship conference of ACM SIGHIT concerned with the application of computer science principles, information science principles, information technology, and communication technology to address problems in healthcare, public health, everyday wellness as well as the related social and ethical issues. There were 321 submissions. 48 and 52 papers were accepted for oral presentations and poster presentations, respectively. There were also 2 keynote speeches, 4 panels, 3 tutorials, 1 extended poster session, and a doctoral consortium. There were over 220 attendees.
How to be a successful app developer
Authors: Lim Soo Ling , Bentley Peter J.
Published: October 2012

App developers are constantly competing against each other to win more downloads for their apps. With hundreds of thousands of apps in these online stores, what strategy should a developer use to be successful? Should they innovate, make many similar apps, optimise their own apps or just copy the apps of others? Looking more deeply, how does a complex app ecosystem perform when developers choose to use different strategies? This paper investigates these questions using AppEco, the first Artificial Life model of mobile application ecosystems. In AppEco, developer agents build and upload apps to the app store; user agents browse the store and download the apps. A distinguishing feature of AppEco is the explicit modelling of apps as artefacts. In this work we use AppEco to simulate Apple's iOS app ecosystem and investigate common developer strategies, evaluating them in terms of downloads received, app diversity, and adoption rate.
Wicked Challenges at Land's End: Managing Coastal Vulnerability Under Climate Change
Authors: Moser Susanne C. , Jeffress Williams S. , Boesch Donald F.
Published: October 2012

With continuing influx of large numbers of people into coastal regions, human stresses on coastal ecosystems and resources are growing at the same time that climate variability and change and associated consequences in the marine environment are making coastal areas less secure for human habitation. The article reviews both climatic and nonclimatic drivers of the growing stresses on coastal natural and human systems, painting a picture of the mostly harmful impacts that result and the interactive and systemic challenges coastal managers face in managing these growing risks. Although adaptive responses are beginning to emerge, the adaptation challenge is enormous and requires not just incremental but also transformative changes. At the same time, such “wicked” problems, by definition, defy all-encompassing, definitive, and final solutions; instead, temporary best solutions will have to be sought in the context of an iterative, deliberately learning-oriented risk management framework.
Defining Akt actions in muscle differentiation
Authors: Gardner Samantha , Anguiano Magdalena , Rotwein Peter
Published: October 2012

Muscle development in childhood and muscle regeneration in adults are highly regulated processes that are necessary for reaching and maintaining optimal muscle mass and strength throughout life. Muscle repair after injury relies on stem cells, termed satellite cells, whose activity is controlled by complex signals mediated by cell-cell contact, by growth factors, and by hormones, which interact with genetic programs controlled by myogenic transcription factors. Insulin-like growth factors (IGFs) play key roles in muscle development and help coordinate muscle repair after injury, primarily by stimulating the phosphatidylinositol 3-kinase-Akt signaling pathway, and both in vitro and in vivo studies have shown that Akt kinase activity is critical for optimal muscle growth and regeneration. Here we find that of the two Akts expressed in muscle, Akt1 is essential for initiation of differentiation in culture and is required for normal myoblast motility, while Akt2 is dispensable. Although Akt2 deficiency did lead to diminished myotube maturation, as assessed by a decline in myofiber area and in fusion index, either Akt1 or Akt2 could restore these processes toward normal. Thus levels of Akt expression rather than distinct actions of individual Akt species are critical for normal myofiber development during the later stages of muscle differentiation.
Acid stress increases gene expression of proinflammatory cytokines in Madin-Darby canine kidney cells
Authors: Raj Suraja , Scott David R. , Nguyen Thomas , Sachs George , Kraut Jeffrey A.
Published: October 2012

Metabolic acidosis is thought to exacerbate chronic kidney disease in part by stimulating the release of potentially injurious substances. To define the genes whose expression is affected by exposure to an acidic milieus, we examined the effect of exposure of MDCK cells to pH 7.4 and pH 7.0 for 24 h on gene expression using a canine derived microarray. Exposure to this pH stress for 24 h led to increased expression of 278 genes (2.2% of the transcriptome) by at least 2-fold and 60 of these (21%) were upregulated by >3-fold. On the other hand, 186 genes (1.5% of the transcriptome) were downregulated by at least 2-fold and 16 of these (9%) were downregulated by 3-fold or more. Ten percent of the genes upregulated by at least threefold encode proinflammatory cytokine proteins, including colony stimulating factor 2, chemokine ligand 7, chemokine ligand 20, chemokine ligand 8, and interleukin-1α. Two others encode metallopeptidases. The most highly upregulated gene encodes a protein, lubricin, shown to be important in preventing cartilage damage and in tissue injury or repair. Upregulation of four genes was confirmed by quantitative PCR. Housekeeping genes were not increased. To examine the effect of decreasing medium pH, we measured intracellular pH (pHi) using 2,7-bis (2-carboxyethyl)5-carboxyfluorescein. With extracellular pH (pHo) of 7.0, pHifell and remained depressed. These findings suggest that a pH stress alone can increase renal expression of proinflammatory and other genes that contribute to renal injury.
Deep brain stimulation of the substantia nigra pars reticulata improves forelimb akinesia in the hemiparkinsonian rat
Authors: Sutton Alexander C. , Yu Wilson , Calos Megan E. , Smith Autumn B. , Ramirez-Zamora Adolfo , Molho Eric S. , Pilitsis Julie G. , Brotchie Jonathan M. , Shin Damian S.
Published: October 2012

Deep brain stimulation (DBS) employing high-frequency stimulation (HFS) is commonly used in the globus pallidus interna (GPi) and the subthalamic nucleus (STN) for treating motor symptoms of patients with Parkinson's disease (PD). Although DBS improves motor function in most PD patients, disease progression and stimulation-induced nonmotor complications limit DBS in these areas. In this study, we assessed whether stimulation of the substantia nigra pars reticulata (SNr) improved motor function. Hemiparkinsonian rats predominantly touched with their unimpaired forepaw >90% of the time in the stepping and limb-use asymmetry tests. After SNr-HFS (150 Hz), rats touched equally with both forepaws, similar to naive and sham-lesioned rats. In vivo, SNr-HFS decreased beta oscillations (12–30 Hz) in the SNr of freely moving hemiparkinsonian rats and decreased SNr neuronal spiking activity from 28 ± 1.9 Hz before stimulation to 0.8 ± 1.9 Hz during DBS in anesthetized animals; also, neuronal spiking activity increased from 7 ± 1.6 to 18 ± 1.6 Hz in the ventromedial portion of the thalamus (VM), the primary SNr efferent. In addition, HFS of the SNr in brain slices from normal and reserpine-treated rat pups resulted in a depolarization block of SNr neuronal activity. We demonstrate improvement of forelimb akinesia with SNr-HFS and suggest that this motor effect may have resulted from the attenuation of SNr neuronal activity, decreased SNr beta oscillations, and increased activity of VM thalamic neurons, suggesting that the SNr may be a plausible DBS target for treating motor symptoms of DBS.
Cerebellar asymmetry and its relation to cerebral asymmetry estimated by intrinsic functional connectivity
Authors: Wang Danhong , Buckner Randy L. , Liu Hesheng
Published: October 2012

Asymmetry of the human cerebellum was investigated using intrinsic functional connectivity. Regions of functional asymmetry within the cerebellum were identified during resting-state functional MRI ( n = 500 subjects) and replicated in an independent cohort ( n = 500 subjects). The most strongly right lateralized cerebellar regions fell within the posterior lobe, including crus I and crus II, in regions estimated to link to the cerebral association cortex. The most strongly left lateralized cerebellar regions were located in lobules VI and VIII in regions linked to distinct cerebral association networks. Comparison of cerebellar asymmetry with independently estimated cerebral asymmetry revealed that the lateralized regions of the cerebellum belong to the same networks that are strongly lateralized in the cerebrum. The degree of functional asymmetry of the cerebellum across individuals was significantly correlated with cerebral asymmetry and varied with handedness. In addition, cerebellar asymmetry estimated at rest predicted cerebral lateralization during an active language task. These results demonstrate that functional lateralization is likely a unitary feature of large-scale cerebrocerebellar networks, consistent with the hypothesis that the cerebellum possesses a roughly homotopic map of the cerebral cortex including the prominent asymmetries of the association cortex.
Intrafascicular stimulation of monkey arm nerves evokes coordinated grasp and sensory responses
Authors: Ledbetter Noah M. , Ethier Christian , Oby Emily R. , Hiatt Scott D. , Wilder Andrew M. , Ko Jason H. , Agnew Sonya P. , Miller Lee E. , Clark Gregory A.
Published: October 2012

High-count microelectrode arrays implanted in peripheral nerves could restore motor function after spinal cord injury or sensory function after limb loss. In this study, we implanted Utah Slanted Electrode Arrays (USEAs) intrafascicularly at the elbow or shoulder in arm nerves of rhesus monkeys ( n = 4) under isoflurane anesthesia. Input-output curves indicated that pulse-width-modulated single-electrode stimulation in each arm nerve could recruit single muscles with little or no recruitment of other muscles. Stimulus trains evoked specific, natural, hand movements, which could be combined via multielectrode stimulation to elicit coordinated power or pinch grasp. Stimulation also elicited short-latency evoked potentials (EPs) in primary somatosensory cortex, which might be used to provide sensory feedback from a prosthetic limb. These results demonstrate a high-resolution, high-channel-count interface to the peripheral nervous system for restoring hand function after neural injury or disruption or for examining nerve structure.
Contribution of near-threshold currents to intrinsic oscillatory activity in rat medial entorhinal cortex layer II stellate cells
Authors: Boehlen Anne , Henneberger Christian , Heinemann Uwe , Erchova Irina
Published: October 2012

The temporal lobe is well known for its oscillatory activity associated with exploration, navigation, and learning. Intrinsic membrane potential oscillations (MPOs) and resonance of stellate cells (SCs) in layer II of the entorhinal cortex are thought to contribute to network oscillations and thereby to the encoding of spatial information. Generation of both MPOs and resonance relies on the expression of specific voltage-dependent ion currents such as the hyperpolarization-activated cation current ( IH), the persistent sodium current ( INaP), and the noninactivating muscarine-modulated potassium current ( IM). However, the differential contributions of these currents remain a matter of debate. We therefore examined how they modify neuronal excitability near threshold and generation of near-threshold MPOs and resonance in vitro. We found that resonance mainly relied on IH and was reduced by IH blockers and modulated by cAMP and an IM enhancer but that neither of the currents exhibited full control over MPOs in these cells. As previously reported, IH controlled a theta-frequency component of MPOs such that blockade of IH resulted in fewer regular oscillations that retained low-frequency components and high peak amplitude. However, pharmacological inhibition and augmentation of IM also affected MPO frequencies and amplitudes. In contrast to other cell types, inhibition of INaP did not result in suppression of MPOs but only in a moderation of their properties. We reproduced the experimentally observed effects in a single-compartment stochastic model of SCs, providing further insight into the interactions between different ionic conductances.
Dichotomy in perceptual learning of interval timing: calibration of mean accuracy and precision differ in specificity and time course
Authors: Sohn Hansem , Lee Sang-Hun
Published: October 2012

Our brain is inexorably confronted with a dynamic environment in which it has to fine-tune spatiotemporal representations of incoming sensory stimuli and commit to a decision accordingly. Among those representations needing constant calibration is interval timing, which plays a pivotal role in various cognitive and motor tasks. To investigate how perceived time interval is adjusted by experience, we conducted a human psychophysical experiment using an implicit interval-timing task in which observers responded to an invisible bar drifting at a constant speed. We tracked daily changes in distributions of response times for a range of physical time intervals over multiple days of training with two major types of timing performance, mean accuracy and precision. We found a decoupled dynamics of mean accuracy and precision in terms of their time course and specificity of perceptual learning. Mean accuracy showed feedback-driven instantaneous calibration evidenced by a partial transfer around the time interval trained with feedback, while timing precision exhibited a long-term slow improvement with no evident specificity. We found that a Bayesian observer model, in which a subjective time interval is determined jointly by a prior and likelihood function for timing, captures the dissociative temporal dynamics of the two types of timing measures simultaneously. Finally, the model suggested that the width of the prior, not the likelihoods, gradually shrinks over sessions, substantiating the important role of prior knowledge in perceptual learning of interval timing.
Lichen Simplex Chronicus That Accompanies Anogenital Warts during the Childhood
Authors: Seçilmiş Kerimoğlu Özlem , Doğan Nasuh Utku , Tazegül Aybike , Karameşe Mehtap , Beyhekim Hasan , Çelik Çetin
Published: October 2012

Anogenital warts and lichen simplex chronicus (LSC) are rarely seen during the childhood. A 9-year-old girl has been presented to hospital by her parents with itching in the anogenital area. There were anogenital warts and a different erythematous lesion in the perianal region. On the pulpa of the right thumb, there was a wart extending under the nail. The lesions are surgically removed. The results of the histopathological examination were reported as condyloma acuminata and LSC. Children with anogenital warts should be examined carefully to discover the transmission route and other possible concomitant cutaneous diseases.
The Dirichlet Problem on the Upper Half‐Space
Authors: Huang Jinjin , Qiao Lei
Published: October 2012

A solution of the Dirichlet problem on the upper half‐space is constructed by the generalized Dirichlet integral with a fast‐growing continuous boundary function.
Double Bolus Application in TWIST-MR-Angiography of the Cervical Arteries
Authors: Korn Andreas , Fenchel Michael , Hauser Till-Karsten , Bisdas Sotirios , Nägele Thomas , Ernemann Ulrike , Klose Uwe , Bender Benjamin
Published: October 2012

Purpose. The aim of the present work was to test the feasibility of the time-resolved MR-angiography (TWIST-MRA) of cervical arteries using double bolus injection.Material and Methods. TWIST-MRA with a temporal resolution of 8.4 seconds for each frame and a spatial resolution with a voxel size of   was performed in 24 patients. A biphasic bolus injection protocol was used with the second injection being started 21 seconds after the first contrast dye bolus. Diagnostic image quality was rated according to a 4-point scale.Results. In 12 patients (50%) no clear separation between the cervical venous and arterial vessels was evident after the first bolus injection. Using TWIST-MRA data acquired after the second bolus a sufficient diagnostic image quality (rating , mean 3.5) could be obtained in 22 of 24 patients (92%).Discussion. The double bolus injection protocol using TWIST-MRA allows for very good separation of the cervical arteries.
Adrenocortical Carcinoma: Current Therapeutic State-of-the-Art
Authors: Lebastchi Amir H. , Kunstman John W. , Carling Tobias
Published: October 2012

Adrenocortical carcinoma (ACC) is a rare, aggressive malignancy that generally conveys a poor prognosis. Currently, surgical resection is considered the lone curative treatment modality. In addition, the low prevalence of ACC has limited effective clinical trial design to develop evidence-based approaches to ACC therapy. The proper role of radio- and chemotherapy treatment for ACC is still being defined. Similarly, the molecular pathogenesis of ACC remains to be fully characterized. Despite these challenges, progress has been made in several areas. After years of refinement, an internationally accepted staging system has been defined. International collaborations have facilitated increasingly robust clinical trials, especially regarding agent choice and patient selection for chemotherapeutics. Genetic array data and molecular profiling have identified new potential targets for rational drug design as well as potential tumor markers and predictors of therapeutic response. However, these advances have not yet been translated into a large outcomes benefit for ACC patients. In this paper, we summarize established therapy for ACC and highlight recent findings in the field that are impacting clinical practice.
A Boundary Integral Equation with the Generalized Neumann Kernel for a Certain Class of Mixed Boundary Value Problem
Authors: Nasser Mohamed M. S. , Murid Ali H. M. , Al-Hatemi Samer A. A.
Published: October 2012

We present a uniquely solvable boundary integral equation with the generalized Neumann kernel for solving two‐dimensional Laplace’s equation on multiply connected regions with mixed boundary condition. Two numerical examples are presented to verify the accuracy of the proposed method.
Structural Health Monitoring of a Tall Building during Construction with Fiber Bragg Grating Sensors
Authors: Li D. S. , Ren L. , Li H. N. , Song G. B.
Published: October 2012

Fiber Bragg grating sensors demonstrate a great potential as a structural health monitoring tool for civil structures to ensure structural integrity, durability, and reliability. The advantages of applying fiber optic sensors to a tall building include their immunity to electromagnetic interference and their multiplexing ability to transfer optical signals over a long distance. In the work, fiber Bragg grating sensors, consisting of strain and temperature sensors, are applied to structural monitoring of an 18-floor tall building since the date of its construction. The strain transferring rate from host material to the fiber core is discussed and the calibration of packaged fiber Bragg grating sensor is presented. The main purposes of the investigation are monitoring temperature evolution history within concrete during the pouring and curing process, measuring variation of the main column strains on the underground floor while upper 18 floors were subsequently added on, and monitoring relative displacement between two foundation blocks. Fiber Bragg grating sensors have been installed and integrated continuously for more than five months. Monitoring results of temperature and strain are presented in the paper. Furthermore, temperature lag behavior between concrete and its surrounding air is investigated.