bluuebunny/crossref_metadata_2025 huggingface dataset:
End-to-end verification of stack-space bounds for C programs
Authors: Carbonneaux Quentin , Hoffmann Jan , Ramananandro Tahina , Shao Zhong
Published: September 2014

Verified compilers guarantee the preservation of semantic properties and thus enable formal verification of programs at the source level. However, important quantitative properties such as memory and time usage still have to be verified at the machine level where interactive proofs tend to be more tedious and automation is more challenging.

This article describes a framework that enables the formal verification of stack-space bounds of compiled machine code at the C level. It consists of a verified CompCert-based compiler that preserves quantitative properties, a verified quantitative program logic for interactive stack-bound development, and a verified stack analyzer that automatically derives stack bounds during compilation.

The framework is based on event traces that record function calls and returns. The source language is CompCert Clight and the target language is x86 assembly. The compiler is implemented in the Coq Proof Assistant and it is proved that crucial properties of event traces are preserved during compilation. A novel quantitative Hoare logic is developed to verify stack-space bounds at the CompCert Clight level. The quantitative logic is implemented in Coq and proved sound with respect to event traces generated by the small-step semantics of CompCert Clight. Stack-space bounds can be proved at the source level without taking into account low-level details that depend on the implementation of the compiler. The compiler fills in these low-level details during compilation and generates a concrete stack-space bound that applies to the produced machine code. The verified stack analyzer is guaranteed to automatically derive bounds for code with non-recursive functions. It generates a derivation in the quantitative logic to ensure soundness as well as interoperability with interactively developed stack bounds.

In an experimental evaluation, the developed framework is used to obtain verified stack-space bounds for micro benchmarks as well as real system code. The examples include the verified operating-system kernel CertiKOS, parts of the MiBench embedded benchmark suite, and programs from the CompCert benchmarks. The derived bounds are close to the measured stack-space usage of executions of the compiled programs on a Linux x86 system.
Slicing probabilistic programs
Authors: Hur Chung-Kil , Nori Aditya V. , Rajamani Sriram K. , Samuel Selva
Published: September 2014

Probabilistic programs use familiar notation of programming languages to specify probabilistic models. Suppose we are interested in estimating the distribution of the return expression
r
of a probabilistic program
P
. We are interested in
slicing
the probabilistic program
P
and obtaining a simpler program Sli(
P
) which retains only those parts of
P
that are relevant to estimating
r
, and elides those parts of
P
that are not relevant to estimating
r
. We desire that the Sli transformation be both correct and efficient. By correct, we mean that
P
and Sli(
P
) have identical estimates on
r
. By efficient, we mean that estimation over Sli(
P
) be as fast as possible.

We show that the usual notion of program slicing, which traverses control and data dependencies backward from the return expression
r
, is unsatisfactory for probabilistic programs, since it produces incorrect slices on some programs and sub-optimal ones on others. Our key insight is that in addition to the usual notions of control dependence and data dependence that are used to slice non-probabilistic programs, a new kind of dependence called
observe dependence
arises naturally due to observe statements in probabilistic programs.

We propose a new definition of Sli(
P
) which is both correct and efficient for probabilistic programs, by including observe dependence in addition to control and data dependences for computing slices. We prove correctness mathematically, and we demonstrate efficiency empirically. We show that by applying the Sli transformation as a pre-pass, we can improve the efficiency of probabilistic inference, not only in our own inference tool R2, but also in other systems for performing inference such as Church and Infer.NET.
Race detection for Android applications
Authors: Maiya Pallavi , Kanade Aditya , Majumdar Rupak
Published: September 2014

Programming environments for smartphones expose a concurrency model that combines multi-threading and asynchronous event-based dispatch. While this enables the development of efficient and feature-rich applications, unforeseen thread interleavings coupled with non-deterministic reorderings of asynchronous tasks can lead to subtle concurrency errors in the applications.

In this paper, we formalize the concurrency semantics of the Android programming model. We further define the
happens-before
relation for Android applications, and develop a dynamic race detection technique based on this relation. Our relation generalizes the so far independently studied happens-before relations for multi-threaded programs and single-threaded event-driven programs. Additionally, our race detection technique uses a model of the Android runtime environment to reduce false positives.

We have implemented a tool called DroidRacer. It generates execution traces by systematically testing Android applications and detects data races by computing the happens-before relation on the traces. We analyzed 15 Android applications including popular applications such as Facebook, Twitter and K-9 Mail. Our results indicate that data races are prevalent in Android applications, and that DroidRacer is an effective tool to identify data races.
Taming the parallel effect zoo
Authors: Kuper Lindsey , Todd Aaron , Tobin-Hochstadt Sam , Newton Ryan R.
Published: September 2014

A fundamental challenge of parallel programming is to ensure that the observable outcome of a program remains deterministic in spite of parallel execution. Language-level enforcement of determinism
is
possible, but existing deterministic-by-construction parallel programming models tend to lack features that would make them applicable to a broad range of problems. Moreover, they lack
extensibility
: it is difficult to add or change language features without breaking the determinism guarantee.

The recently proposed
LVars
programming model, and the accompanying
LVish
Haskell library, took a step toward broadly-applicable guaranteed-deterministic parallel programming. The LVars model allows communication through shared
monotonic data structures
to which information can only be added, never removed, and for which the order in which information is added is not observable. LVish provides a Par monad for parallel computation that encapsulates determinism-preserving effects while allowing a more flexible form of communication between parallel tasks than previous guaranteed-deterministic models provided.

While applying LVar-based programming to real problems using LVish, we have identified and implemented three capabilities that extend its reach: inflationary updates other than least-upper-bound writes; transitive task cancellation; and parallel mutation of non-overlapping memory locations. The unifying abstraction we use to add these capabilities to LVish---without suffering added complexity or cost in the core LVish implementation, or compromising determinism---is a form of
monad transformer
, extended to handle the Par monad. With our extensions, LVish provides the most broadly applicable guaranteed-deterministic parallel programming interface available to date. We demonstrate the viability of our approach both with traditional parallel benchmarks and with results from a real-world case study: a bioinformatics application that we parallelized using our extended version of LVish.
Optimal inference of fields in row-polymorphic records
Authors: Simon Axel
Published: September 2014

Flexible records are a powerful concept in type systems that form the basis of, for instance, objects in dynamically typed languages. One caveat of using flexible records is that a program may try to access a record field that does not exist. We present a type inference algorithm that checks for these runtime errors. The novelty of our algorithm is that it satisfies a clear notion of completeness: The inferred types are optimal in the sense that type annotations cannot increase the set of typeable programs. Under certain assumptions, our algorithm guarantees the following stronger property: it rejects a program if and only if it contains a path from an empty record to a field access on which the field has not been added. We derive this optimal algorithm by abstracting a semantics to types. The derived inference rules use a novel combination of type terms and Boolean functions that retains the simplicity of unification-based type inference but adds the ability of Boolean functions to express implications, thereby addressing the challenge of combining implications and types. By following our derivation method, we show how various operations such as record concatenation and branching if a field exists lead to Boolean satisfiability problems of different complexity. Analogously, we show that more expressive type systems give rise to SMT problems. On the practical side, we present an implementation of the select and update operations and give practical evidence that these are sufficient in real-world applications.
VeriCon
Authors: Ball Thomas , Bjørner Nikolaj , Gember Aaron , Itzhaky Shachar , Karbyshev Aleksandr , Sagiv Mooly , Schapira Michael , Valadarsky Asaf
Published: September 2014

Software-defined networking (SDN) is a new paradigm for operating and managing computer networks. SDN enables logically-centralized control over network devices through a "controller" software that operates independently from the network hardware, and can be viewed as the network operating system. Network operators can run both inhouse and third-party SDN programs (often called applications) on top of the controller, e.g., to specify routing and access control policies. SDN opens up the possibility of applying formal methods to prove the correctness of computer networks. Indeed, recently much effort has been invested in applying finite state model checking to check that SDN programs behave correctly. However, in general, scaling these methods to large networks is challenging and, moreover, they cannot guarantee the absence of errors.

We present VeriCon, the first system for verifying that an SDN program is correct on
all
admissible topologies and for
all
possible (infinite) sequences of network events. VeriCon either confirms the correctness of the controller program on
all
admissible network topologies or outputs a concrete counterexample. VeriCon uses first-order logic to specify admissible network topologies and desired network-wide invariants, and then implements classical Floyd-Hoare-Dijkstra deductive verification using Z3. Our preliminary experience indicates that VeriCon is able to rapidly verify correctness, or identify bugs, for a large repertoire of simple core SDN programs. VeriCon is compositional, in the sense that it verifies the correctness of execution of any single network event w.r.t. the specified invariant, and can thus scale to handle large programs. To relieve the burden of specifying inductive invariants from the programmer, VeriCon includes a separate procedure for inferring invariants, which is shown to be effective on simple controller programs. We view VeriCon as a first step en route to practical mechanisms for verifying network-wide invariants of SDN programs.
Resugaring
Authors: Pombrio Justin , Krishnamurthi Shriram
Published: September 2014

Syntactic sugar is pervasive in language technology. It is used to shrink the size of a core language; to define domain-specific languages; and even to let programmers extend their language. Unfortunately, syntactic sugar is eliminated by transformation, so the resulting programs become unfamiliar to authors. Thus, it comes at a price: it obscures the relationship between the user's source program and the program being evaluated.

We address this problem by showing how to compute reduction steps in terms of the surface syntax. Each step in the surface language emulates one or more steps in the core language. The computed steps hide the transformation, thus maintaining the abstraction provided by the surface language. We make these statements about emulation and abstraction precise, prove that they hold in our formalism, and verify part of the system in Coq. We have implemented this work and applied it to three very different languages.
Hybrid top-down and bottom-up interprocedural analysis
Authors: Zhang Xin , Mangal Ravi , Naik Mayur , Yang Hongseok
Published: September 2014

Interprocedural static analyses are broadly classified into top-down and bottom-up, depending upon how they compute, instantiate, and reuse procedure summaries. Both kinds of analyses are challenging to scale: top-down analyses are hindered by ineffective reuse of summaries whereas bottom-up analyses are hindered by inefficient computation and instantiation of summaries. This paper presents a hybrid approach Swift that combines top-down and bottom-up analyses in a manner that gains their benefits without suffering their drawbacks. Swift is general in that it is parametrized by the top-down and bottom-up analyses it combines. We show an instantiation of Swift on a type-state analysis and evaluate it on a suite of 12 Java programs of size 60-250 KLOC each. Swift outperforms both conventional approaches, finishing on all the programs while both of those approaches fail on the larger programs.
Race detection for event-driven mobile applications
Authors: Hsiao Chun-Hung , Yu Jie , Narayanasamy Satish , Kong Ziyun , Pereira Cristiano L. , Pokam Gilles A. , Chen Peter M. , Flinn Jason
Published: September 2014

Mobile systems commonly support an event-based model of concurrent programming. This model, used in popular platforms such as Android, naturally supports mobile devices that have a rich array of sensors and user input modalities. Unfortunately, most existing tools for detecting concurrency errors of parallel programs focus on a thread-based model of concurrency. If one applies such tools directly to an event-based program, they work poorly because they infer false dependencies between unrelated events handled sequentially by the same thread.

In this paper we present a race detection tool named CAFA for event-driven mobile systems. CAFA uses the causality model that we have developed for the Android event-driven system. A novel contribution of our model is that it accounts for the causal order due to the event queues, which are not accounted for in past data race detectors. Detecting races based on low-level races between memory accesses leads to a large number of false positives. CAFA overcomes this problem by checking for races between high-level operations. We discuss our experience in using CAFA for finding and understanding a number of known and unknown harmful races in open-source Android applications.
Compiler validation via equivalence modulo inputs
Authors: Le Vu , Afshari Mehrdad , Su Zhendong
Published: September 2014

We introduce
equivalence modulo inputs (EMI)
, a simple, widely applicable methodology for validating optimizing compilers. Our key insight is to exploit the close interplay between (1) dynamically executing a program on some test inputs and (2) statically compiling the program to work on all possible inputs. Indeed, the test inputs induce a natural collection of the original program's EMI variants, which can help differentially test any compiler and specifically target the difficult-to-find miscompilations.

To create a practical implementation of EMI for validating C compilers, we profile a program's test executions and stochastically prune its unexecuted code. Our extensive testing in eleven months has led to 147 confirmed, unique bug reports for GCC and LLVM alone. The majority of those bugs are miscompilations, and more than 100 have already been fixed.

Beyond testing compilers, EMI can be adapted to validate program transformation and analysis systems in general. This work opens up this exciting, new direction.
Test-driven repair of data races in structured parallel programs
Authors: Surendran Rishi , Raman Raghavan , Chaudhuri Swarat , Mellor-Crummey John , Sarkar Vivek
Published: September 2014

A common workflow for developing parallel software is as follows: 1) start with a sequential program, 2) identify subcomputations that should be converted to parallel tasks, 3) insert synchronization to achieve the same semantics as the sequential program, and repeat steps 2) and 3) as needed to improve performance. Though this is not the only approach to developing parallel software, it is sufficiently common to warrant special attention as parallel programming becomes ubiquitous. This paper focuses on automating step 3), which is usually the hardest step for developers who lack expertise in parallel programming.

Past solutions to the problem of repairing parallel programs have used static-only or dynamic-only approaches, both of which incur significant limitations in practice. Static approaches can guarantee soundness in many cases but are limited in precision when analyzing medium or large-scale software with accesses to pointer-based data structures in multiple procedures. Dynamic approaches are more precise, but their proposed repairs are limited to a single input and are not reflected back in the original source program. In this paper, we introduce a hybrid static+dynamic test-driven approach to repairing data races in structured parallel programs. Our approach includes a novel coupling between static and dynamic analyses. First, we execute the program on a concrete test input and determine the set of data races for this input dynamically. Next, we compute a set of "finish" placements that prevent these races and also respects the static scoping rules of the program while maximizing parallelism. Empirical results on standard benchmarks and student homework submissions from a parallel computing course establish the effectiveness of our approach with respect to compile-time overhead, precision, and performance of the repaired code.
A lightweight symbolic virtual machine for solver-aided host languages
Authors: Torlak Emina , Bodik Rastislav
Published: September 2014

Solver-aided domain-specific languages (SDSLs) are an emerging class of computer-aided programming systems. They ease the construction of programs by using satisfiability solvers to automate tasks such as verification, debugging, synthesis, and non-deterministic execution. But reducing programming tasks to satisfiability problems involves translating programs to logical constraints, which is an engineering challenge even for domain-specific languages.

We have previously shown that translation to constraints can be avoided if SDSLs are implemented by (traditional) embedding into a host language that is itself solver-aided. This paper describes how to implement a symbolic virtual machine (SVM) for such a host language. Our symbolic virtual machine is lightweight because it compiles to constraints only a small subset of the host's constructs, while allowing SDSL designers to use the entire language, including constructs for DSL embedding. This lightweight compilation employs a novel symbolic execution technique with two key properties: it produces compact encodings, and it enables concrete evaluation to strip away host constructs that are outside the subset compilable to constraints. Our symbolic virtual machine architecture is at the heart of Rosette, a solver-aided language that is host to several new SDSLs.
Dynamic space limits for Haskell
Authors: Yang Edward Z. , Mazières David
Published: September 2014

We describe the semantics and implementation of a space limits system for Haskell, which allows programmers to create resource containers that enforce bounded resident memory usage at runtime. Our system is distinguished by a clear allocator-pays semantics drawn from previous experience with profiling in Haskell and an implementation strategy which uses a block-structured heap to organize containers, allowing us to enforce limits with high accuracy. To deal with the problem of deallocating data in a garbage collected heap, we propose a novel taint-based mechanism that unifies the existing practices of revocable pointers and killing threads in order to reclaim memory. Our system is implemented in GHC, a production-strength compiler for Haskell.
VOBLA
Authors: Beaugnon Ulysse , Kravets Alexey , van Haastregt Sven , Baghdadi Riyadh , Tweed David , Absar Javed , Lokhmotov Anton
Published: September 2014

We present VOBLA, a domain-specific language designed for programming linear algebra libraries. VOBLA is compiled to PENCIL, a domain independent intermediate language designed for efficient mapping to accelerator architectures such as GPGPUs. PENCIL is compiled to efficient, platform-specific OpenCL code using techniques based on the polyhedral model. This approach addresses both the programmer productivity and performance portability concerns associated with accelerator programming.

We demonstrate our approach by using VOBLA to implement a BLAS library. We have evaluated the performance of OpenCL code generated using our compilation flow on ARM Mali, AMD Radeon, and AMD Opteron platforms. The generated code is currently on average 1.9x slower than highly hand-optimized OpenCL code, but on average 8.1x faster than straightforward OpenCL code. Given that the VOBLA coding takes significantly less effort compared to hand-optimizing OpenCL code, we believe our approach leads to improved productivity and performance portability.
Refining piecewise stationary approximation for a Markov-regulated fluid queue
Authors: Zhang Bo , Pang Guodong , Zwart Bert
Published: September 2014

This paper presents a refinement of the Piecewise Stationary Approximation for the stationary distribution of a Markov-regulated uid queue. The refinement is analytically justified. Its accuracy and utility are demonstrated.
On the probability of current and temperature overloading in power grids
Authors: Bosman Joost , Nair Jayakrishnan , Zwart Bert
Published: September 2014

The advent of renewable energy sources has huge implications for the design and control of power grids. On the engineering side, reliability is currently ensured by strict con- straints on current, voltage and temperature. However, with growing supply-side uncertainty induced by renewables, these will need to be replaced by probabilistic guarantees, allowing constraints on a given line to be violated with a low probability, e.g., several minutes per year. In the present note we illustrate, using large deviations techniques, how replacing (probabilistic) current constraints by temperature constraints can lead to capacity gains in power grids.
Maximum entropy traffic matrix synthesis
Authors: Tune Paul , Roughan Matthew
Published: September 2014

The traffic matrix (TM) is an important input in traffic engineering and network design. However, the design of current synthesis models of TMs has been rather ad hoc, and does not necessarily conform to observed traffic constraints. We apply the principle of maximum entropy to develop fast TM synthesis models, with the future goal of developing realistic spatio-temporal TMs.
Rab11, but not Rab4, facilitates cyclic AMP- and tauroursodeoxycholate-induced MRP2 translocation to the plasma membrane
Authors: Park Se Won , Schonhoff Christopher M. , Webster Cynthia R. L. , Anwer M. Sawkat
Published: September 2014

Rab proteins (Ras homologous for brain) play an important role in vesicle trafficking. Rab4 and Rab11 are involved in vesicular trafficking to the plasma membrane from early endosomes and recycling endosomes, respectively. Tauroursodeoxycholate (TUDC) and cAMP increase bile formation, in part, by increasing plasma membrane localization of multidrug resistance-associated protein 2 (MRP2). The goal of the present study was to determine the role of these Rab proteins in the trafficking of MRP2 by testing the hypothesis that Rab11 and/or Rab4 facilitate cAMP- and TUDC-induced MRP2 translocation to the plasma membrane. Studies were conducted in HuH-NTCP cells (HuH7 cells stably transfected with human NTCP), which constitutively express MRP2. HuH-NTCP cells were transfected with Rab11-WT and GDP-locked dominant inactive Rab11-GDP or with Rab4-GDP to study the role of Rab11 and Rab4. A biotinylation method and a GTP overlay assay were used to determine plasma membrane MRP2 and activation of Rab proteins (Rab11 and Rab4), respectively. Cyclic AMP and TUDC increased plasma membrane MRP2 and stimulated Rab11 activity. Plasma membrane translocation of MRP2 by cAMP and TUDC was increased and inhibited in cells transfected with Rab11-WT and Rab11-GDP, respectively. Cyclic AMP (previous study) and TUDC increased Rab4 activity. However, cAMP- and TUDC-induced increases in MRP2 were not inhibited by Rab4-GDP. Taken together, these results suggest that Rab11 is involved in cAMP- and TUDC-induced MRP2 translocation to the plasma membrane.
Adrenergic control of lipolysis in women compared with men
Authors: Schmidt Stacy L. , Bessesen Daniel H. , Stotz Sarah , Peelor Frederick F. , Miller Benjamin F. , Horton Tracy J.
Published: September 2014

Data suggest women are more sensitive to the lipolytic action of epinephrine compared with men while maintaining similar glucoregulatory effects (Horton et al. J Appl Physiol 107: 200–210, 2009). This study aimed to determine the specific adrenergic receptor(s) that may mediate these sex differences. Lean women ( n = 14) and men ( n = 16) were studied on 4 nonconsecutive days during the following treatment infusions: saline (S: control), epinephrine [E: mixed β-adrenergic (lipolytic) and α2-adrenergic (antilipolytic) stimulation], epinephrine + phentolamine (E + P: mixed β-adrenergic stimulation only), and terbutaline (T: selective β2-adrenergic stimulation). Tracer infusions of glycerol, palmitate, and glucose were administered to determine systemic lipolysis, free fatty acid (FFA) release, and glucose turnover, respectively. Following basal measurements, substrate and hormone concentrations were measured in all subjects over 90 min of treatment and tracer infusion. Women had greater increases in glycerol and FFA concentrations with all three hormone infusions compared with men ( P < 0.01). Glycerol and palmitate rate of appearance (Ra) and rate of disappearance (Rd) per kilogram body weight were greater with E infusion in women compared with men ( P < 0.05), whereas no sex differences were observed with other treatments. Glucose concentration and kinetics were not different between sexes with any infusion. In conclusion, these data support the hypothesis that the greater rate of lipolysis in women with infusion of E was likely due to lesser α2antilipolytic activation. These findings may help explain why women have greater lipolysis and fat oxidation during exercise, a time when epinephrine concentration is elevated.
Aerobic exercise attenuates pulmonary inflammation induced byStreptococcus pneumoniae
Authors: Olivo Clarice R. , Miyaji Eliane N. , Oliveira Maria Leonor S. , Almeida Francine M. , Lourenço Juliana D. , Abreu Rodrigo M. , Arantes Petra M. M. , Lopes Fernanda DTQS , Martins Milton A.
Published: September 2014

Aerobic exercise has been recognized as a stimulator of the immune system, but its effect on bacterial infection has not been extensively evaluated. We studied whether moderate aerobic exercise training prior to Streptococcus pneumoniae infection influences pulmonary inflammatory responses. BALB/c mice were divided into four groups: Sedentary Untreated (sedentary without infection); Sedentary Infected (sedentary with infection); Trained Untreated (aerobic training without infection); and Trained Infected (aerobic training with infection). Animals underwent aerobic training for 4 wk, and 72 h after last exercise training, animals received a challenge with S. pneumoniae and were evaluated either 12 h or 10 days after instillation. In acute phase, Sedentary Infected group had an increase in respiratory system resistance and elastance; number of neutrophils, lymphocytes, and macrophages in bronchoalveolar lavage fluid (BAL); polymorphonuclear cells in lung parenchyma; and levels of keratinocyte-derived chemokine (KC), tumor necrosis factor-α (TNF-α), and interleukin (IL)−1β (IL-1β) in lung homogenates. Exercise training significantly attenuated the increase in all of these parameters and induced an increase in expression of antioxidant enzymes (CuZnSOD and MnSOD) in lungs. Trained Infected mice had a significant decrease in the number of colony-forming units of pneumococci in the lungs compared with Sedentary Infected animals. Ten days after infection, Trained Infected group exhibited lower numbers of macrophages in BAL, polymorphonuclear cells in lung parenchyma and IL-6 in lung homogenates compared with Sedentary Infected group. Our results suggest a protective effect of moderate exercise training against respiratory infection with S. pneumoniae. This effect is most likely secondary to an effect of exercise on oxidant-antioxidant balance.
Assessment of middle cerebral artery diameter during hypocapnia and hypercapnia in humans using ultra-high-field MRI
Authors: Verbree Jasper , Bronzwaer Anne-Sophie G. T. , Ghariq Eidrees , Versluis Maarten J. , Daemen Mat J. A. P. , van Buchem Mark A. , Dahan Albert , van Lieshout Johannes J. , van Osch Matthias J. P.
Published: September 2014

In the evaluation of cerebrovascular CO2 reactivity measurements, it is often assumed that the diameter of the large intracranial arteries insonated by transcranial Doppler remains unaffected by changes in arterial CO2 partial pressure. However, the strong cerebral vasodilatory capacity of CO2 challenges this assumption, suggesting that there should be some changes in diameter, even if very small. Data from previous studies on effects of CO2 on cerebral artery diameter [middle cerebral artery (MCA)] have been inconsistent. In this study, we examined 10 healthy subjects (5 women, 5 men, age 21–30 yr). High-resolution (0.2 mm in-plane) MRI scans at 7 Tesla were used for direct observation of the MCA diameter during hypocapnia, −1 kPa (−7.5 mmHg), normocapnia, 0 kPa (0 mmHg), and two levels of hypercapnia, +1 and +2 kPa (7.5 and 15 mmHg), with respect to baseline. The vessel lumen was manually delineated by two independent observers. The results showed that the MCA diameter increased by 6.8 ± 2.9% in response to 2 kPa end-tidal Pco2 (PetCO2) above baseline. However, no significant changes in diameter were observed at the −1 kPa (−1.2 ± 2.4%), and +1 kPa (+1.4 ± 3.2%) levels relative to normocapnia. The nonlinear response of the MCA diameter to CO2 was fitted as a continuous calibration curve. Cerebral blood flow changes measured by transcranial Doppler could be corrected by this calibration curve using concomitant PetCO2 measurements. In conclusion, the MCA diameter remains constant during small deviations of the PetCO2 from normocapnia, but increases at higher PetCO2 values.
Concurrent speed endurance and resistance training improves performance, running economy, and muscle NHE1 in moderately trained runners
Authors: Skovgaard Casper , Christensen Peter M. , Larsen Sonni , Andersen Thomas Rostgaard , Thomassen Martin , Bangsbo Jens
Published: September 2014

The purpose of this study was to examine whether speed endurance training (SET, repeated 30-s sprints) and heavy resistance training (HRT, 80–90% of 1 repetition maximum) performed in succession are compatible and lead to performance improvements in moderately trained endurance runners. For an 8-wk intervention period (INT) 23 male runners [maximum oxygen uptake (V̇o2max) 59 ± 1 ml·min−1·kg−1; values are means ± SE] either maintained their training (CON, n = 11) or performed high-intensity concurrent training (HICT, n = 12) consisting of two weekly sessions of SET followed by HRT and two weekly sessions of aerobic training with an average reduction in running distance of 42%. After 4 wk of HICT, performance was improved ( P < 0.05) in a 10-km run (42:30 ± 1:07 vs. 44:11 ± 1:08 min:s) with no further improvement during the last 4 wk. Performance in a 1,500-m run (5:10 ± 0:05 vs. 5:27 ± 0:08 min:s) and in the Yo-Yo IR2 test (706 ± 97 vs. 491 ± 65 m) improved ( P < 0.001) only following 8 wk of INT. In HICT, running economy (189 ± 4 vs. 195 ± 4 ml·kg−1·km−1), muscle content of NHE1 (35%) and dynamic muscle strength was augmented ( P < 0.01) after compared with before INT, whereas V̇o2max, muscle morphology, capillarization, content of muscle Na+/K+ pump subunits, and MCT4 were unaltered. No changes were observed in CON. The present study demonstrates that SET and HRT, when performed in succession, lead to improvements in both short- and long-term running performance together with improved running economy as well as increased dynamic muscle strength and capacity for muscular H+ transport in moderately trained endurance runners.
Histomorphologic and Immunohistochemical Characterization of a Cardiac Purkinjeoma in a Bearded Seal (Erignathus barbatus)
Authors: Krafsur G. , Ehrhart E. J. , Ramos-Vara J. , Mason G. , Sarren F. , Adams B. , Hanns C. , Spraker T. , Duncan C.
Published: August 2014

The most common cardiac tumors of heart muscle are rhabdomyomas, solitary or multiple benign tumors of striated muscle origin. While cardiac rhabdomyomas are well described in human medical literature, limited information depicting the occurrence of cardiac rhabdomyomas in veterinary species exists. A case of multiple firm white nonencapsulated nodules in the heart of a bearded seal is described. Microscopic findings included cytoplasmic vacuolization with formation of spider cells, glycogen vacuoles, and striated myofibrils. These cells expressed immunoreactivity for neuron-specific enolase and protein gene product 9.5, a marker for neuronal tissue and Purkinje fiber cells. Immunoreactivity for protein gene product 9.5 along with other microscopic findings substantiates Purkinje fiber cell origin of the cardiac rhabdomyoma in the bearded seal and use of the termpurkinjeomato describe this lesion.
The Equine CD4+ Lymphocyte Proteome
Authors: Degroote Roxane L. , Helm Sandra , Klein Ute , Schmitt Ramona , Ueffing Marius , Hauck Stefanie M. , Deeg Cornelia A.
Published: September 2014

CD4+ T cells are key players in immunology and disease pathology, including relapsing autoimmune uveitis. Equine recurrent uveitis is the only spontaneous animal model for this disease in man. Knowledge about the CD4+ cell proteome is crucial for studies on possible changes in proteome expression of CD4+ effector cells in disease. For this purpose, we generated a reference dataset of the equine CD4+ cell proteome by sorting equine CD4+ lymphocytes followed by analysis of whole cell lysate as well as membrane protein fraction using mass spectrometry.
Electrochemical Synthesis of Magnesium Hexaboride by Molten Salt Technique
Authors: Angappan S. , Kalaiselvi N. , Sudha R. , Visuvasam A.
Published: August 2014

The present work reports electrochemical synthesis of MgB6from molten salts using the precursor consists of LiF–B2O3–MgCl2. An attempt has been made to synthesize metastable phase MgB6crystal by electrolysis method. DTA/TGA studies were made to determine the eutectic point of the melt and it was found to be around 900°C. The electrolysis was performed at 900°C under argon atmosphere, at current density of 1.5 A/cm2. The electrodeposited crystals were examined using XRD, SEM, and XPS. From the above studies, the electrochemical synthesis method for hypothetical MgB6from chloro-oxy-fluoride molten salt system is provided. Mechanism for the formation of magnesium hexaboride is discussed.
Color Image Segmentation Based on Different Color Space Models Using Automatic GrabCut
Authors: Khattab Dina , Ebied Hala Mousher , Hussein Ashraf Saad , Tolba Mohamed Fahmy
Published: August 2014

This paper presents a comparative study using different color spaces to evaluate the performance of color image segmentation using the automatic GrabCut technique. GrabCut is considered as one of the semiautomatic image segmentation techniques, since it requires user interaction for the initialization of the segmentation process. The automation of the GrabCut technique is proposed as a modification of the original semiautomatic one in order to eliminate the user interaction. The automatic GrabCut utilizes the unsupervised Orchard and Bouman clustering technique for the initialization phase. Comparisons with the original GrabCut show the efficiency of the proposed automatic technique in terms of segmentation, quality, and accuracy. As no explicit color space is recommended for every segmentation problem, automatic GrabCut is applied withRGB,HSV,CMY,XYZ, andYUVcolor spaces. The comparative study and experimental results using different color images show thatRGBcolor space is the best color space representation for the set of the images used.
Effect of Hydroxypropylation on Functional Properties of Different Cultivars of Sweet Potato Starch in Sri Lanka
Authors: Senanayake Suraji , Gunaratne Anil , Ranaweera K. K. D. S. , Bamunuarachchi Arthur
Published: August 2014

Starches obtained from different cultivars of sweet potatoes commonly consumed in Sri Lanka, were chemically modified with hydroxypropyl substitution, to analyze the changes in the physicochemical properties. Significant changes (P<0.05) in the crude digestibility level, thermal properties, and the water separation (syneresis) of starch gels (7.0% db) during cold and frozen storage were observed due to the modification. Hydroxypropylation increased the gel stability, water solubility, digestibility, and storage stability of the native starches in the cold storage to a significant level. Lowered gelatinization and retrogradation enthalpies as well as gelatinization temperature were observed for derivatized starches compared to the native starch. Low levels of pasting stability with increased levels of breakdown and reduced cold paste viscosity were observed in the hydroxypropylated starch samples except for the Malaysian cultivar (S5). Chemically modified starch gels stored under cold storage did not show a syneresis for two weeks in the cycle and the frozen storage showed much improved stability in the starch gels within the four-week cycle. Chemical modification of sweet potato starch with hydroxyl propyl substitution can enhance the functional characteristics of the native starch which will improve its potential application in the food industry.
Autogenerator-Based Modelling Framework for Development of Strategic Games Simulations: Rational Pigs Game Extended
Authors: Fabac Robert , Radošević Danijel , Magdalenić Ivan
Published: August 2014

When considering strategic games from the conceptual perspective that focuses on the questions of participants’ decision-making rationality, the very issues of modelling and simulation are rarely discussed. The well-known Rational Pigs matrix game has been relatively intensively analyzed in terms of reassessment of the logic of two players involved in asymmetric situations as gluttons that differ significantly by their attributes. This paper presents a successful attempt of using autogenerator for creating the framework of the game, including the predefined scenarios and corresponding payoffs. Autogenerator offers flexibility concerning the specification of game parameters, which consist of variations in the number of simultaneous players and their features and game objects and their attributes as well as some general game characteristics. In the proposed approach the model of autogenerator was upgraded so as to enable program specification updates. For the purpose of treatment of more complex strategic scenarios, we created the Rational Pigs Game Extended (RPGE), in which the introduction of a third glutton entails significant structural changes. In addition, due to the existence of particular attributes of the new player, “the tramp,” one equilibrium point from the original game is destabilized which has an influence on the decision-making of rational players.
Development of a Wheelchair Skills Home Program for Older Adults Using a Participatory Action Design Approach
Authors: Giesbrecht Edward M. , Miller William C. , Mitchell Ian M. , Woodgate Roberta L.
Published: September 2014

Restricted mobility is the most common impairment among older adults and a manual wheelchair is often prescribed to address these limitations. However, limited access to rehabilitation services results in older adults typically receiving little or no mobility training when they receive a wheelchair. As an alternative and novel approach, we developed a therapist-monitored wheelchair skills home training program delivered via a computer tablet. To optimize efficacy and adherence, principles of self-efficacy and adult learning theory were foundational in the program design. A participatory action design approach was used to engage older adult wheelchair users, care providers, and prescribing clinicians in an iterative design and development process. A series of prototypes were fabricated and revised, based on feedback from eight stakeholder focus groups, until a final version was ready for evaluation in a clinical trial. Stakeholder contributions affirmed and enhanced the foundational theoretical principles and provided validation of the final product for the target population.
Proteomics Analysis for Finding Serum Markers of Ovarian Cancer
Authors: Cheng Yushan , Liu Chongdong , Zhang Nawei , Wang Shengdian , Zhang Zhenyu
Published: August 2014

A combination of peptide ligand library beads (PLLB) and 1D gel liquid chromatography-mass spectrometry/mass spectrometry (1DGel-LC-MS/MS) was employed to analyze serum samples from patients with ovarian cancer and from healthy controls. Proteomic analysis identified 1200 serum proteins, among which 57 proteins were upregulated and 10 were downregulated in the sera from cancer patients. Retinol binding protein 4 (RBP4) is highly upregulated in the ovarian cancer serum samples. ELISA was employed to measure plasma concentrations of RBP4 in 80 samples from ovarian cancer patients, healthy individuals, myoma patients, and patients with benign ovarian tumor, respectively. The plasma concentrations of RBP4 ranging from 76.91 to 120.08 ng/mL with the mean value89.13±1.67 ng/mL in ovarian cancer patients are significantly higher than those in healthy individuals (10.85±2.38 ng/mL). Results were further confirmed with immunohistochemistry, demonstrating that RBP4 expression levels in normal ovarian tissue were lower than those in ovarian cancer tissues. Our results suggested that RBP4 is a potential biomarker for diagnostic of screening ovarian cancer.
Electron Transfer of Myoglobin Immobilized in Au Electrodes Modified with a RAFT PMMA-Block-PDMAEMA Polymer
Authors: Toledo Carla N. , Florenzano Fábio H. , Schneedorf José M.
Published: August 2014

Myoglobin was immobilized with poly(methyl methacrylate)-block-poly[(2-dimethylamino)ethyl methacrylate]PMMA-block-PDMAEMA polymer synthesized by reversible addition-fragmentation chain transfer technique (RAFT). Cyclic voltammograms gave direct and slow quasireversible heterogeneous electron transfer kinetics between Mb-PMMA-block-PDMAEMA modified electrode and the redox center of the protein. The values for electron rate constant (Ks) and transfer coefficient (α) were0.055±0.01·s−1and0.81±0.08, respectively. The reduction potential determined as a function of temperature (293–328 K) revealed a value of reaction center entropy ofΔS0of351.3±0.0002 J·mol−1·K−1and enthalpy change of-76.8±0.1 kJ·mol−1, suggesting solvent effects and charge ionization atmosphere involved in the reaction parallel to hydrophobic interactions with the copolymer. The immobilized protein also exhibits an electrocatalytical response to reduction of hydrogen peroxide, with an apparentKmof114.7±58.7 μM. The overall results substantiate the design and use of RAFT polymers towards the development of third-generation biosensors.
Optimal and Suboptimal Resource Allocation in MIMO Cooperative Cognitive Radio Networks
Authors: Ghamari Adian Mehdi , Ghamari Adyan Mahin
Published: August 2014

The core aim of this work is the maximization of the achievable data rate of the secondary user pairs (SU pairs), while ensuring the QoS of primary users (PUs). All users are assumed to be equipped with multiple antennas. It is assumed that when PUs are present, the direct communication between SU pairs introduces intolerable interference to PUs and thereby SUs transmit signal using the cooperation of one of the SUs and avoid transmission in the direct channel. In brief, an adaptive cooperative strategy for MIMO cognitive radio networks is proposed. At the presence of PUs, the issue of joint relay selection and power allocation in underlay MIMO cooperative cognitive radio networks (U-MIMO-CCRN) is addressed. The optimal approach for determining the power allocation and the cooperating SU is proposed. Besides, the outage probability of the proposed system is further derived. Due to high complexity of the optimal approach, a low complexity approach is further proposed and its performance is evaluated using simulations. The simulation results reveal that the performance loss due to the low complexity approach is only about 14%, while the complexity is greatly reduced.
Destabilization of Akt Promotes the Death of Myeloma Cell Lines
Authors: Zhang Yanan , Fu Yunfeng , Zhang Fan , Liu Jing
Published: August 2014

Constitutive activation of Akt is believed to be an oncogenic signal in multiple myeloma and is associated with poor patient prognosis and resistance to available treatment. The stability of Akt proteins is regulated by phosphorylating the highly conserved turn motif (TM) of these proteins and the chaperone protein HSP90. In this study we investigate the antitumor effects of inhibiting mTORC2 plus HSP90 in myeloma cell lines. We show that chronic exposure of cells to rapamycin can inhibit mTORC2 pathway, and AKT will be destabilized by administration of the HSP90 inhibitor 17-allylamino-geldanamycin (17-AAG). Finally, we show that the rapamycin synergizes with 17-AAG and inhibits myeloma cells growth and promotes cell death to a greater extent than either drug alone. Our studies provide a clinical rationale of use mTOR inhibitors and chaperone protein inhibitors in combination regimens for the treatment of human blood cancers.
Diarylheptanoids from Alpinia officinarum Cause Distinct but Overlapping Effects on the Translatome of B Lymphoblastoid Cells
Authors: Kakegawa Tomohito , Takase Saeko , Masubuchi Eri , Yasukawa Ken
Published: August 2014

Diarylheptanoids (AO‐0001, AO‐0002, and AO‐0003) isolated from Alpinia officinarum inhibit proinflammatory mediators and exhibit cytotoxic and antiviral activity. However, the precise mechanisms of action of these diarylheptanoids are unknown as are their effects on expression of specific genes. Here, we used a translatome analysis to investigate the mechanisms and modes of action of these three diarylheptanoids. Polysome‐associated messenger RNAs (mRNAs) were prepared from diarylheptanoids‐treated and control cells from a human B lymphoblastoid cell line; these mRNA samples were then used for microarray analysis. Microarray Data Analysis Tool version 3.2 was used to analyze the microarray data analysis; this software uses pathway information of the WikiPathways for gene ontology analysis. Each of the diarylheptanoids caused upregulation or downregulation of the same 37 and 286 genes, respectively. Among the 37 upregulated genes, 16 were related to mRNA processing based on the WikiPathways analysis. Our findings provided new insights into the mode of action of diarylheptanoids from A. officinarum.