bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Therapeutic Effect of Cornus officinalis Fruits on the Damage of Different Organs in STZ-Induced Diabetic Rats
Authors: Han Yunkyung , Jung Hyo Won , Park Yong-Ki
Published: August 2014

The aim of the present study was to identify the selective therapeutic effects of Corni Fructus (Cornus officinalis Sieb. et Zucc.) on different organs in streptozotocin (STZ)-induced diabetic rats. Diabetes in rats was induced by intraperitonal injection with STZ at a dose of 30 mg/kg body weight (bw) for 3 days (once per a day). STZ-induced diabetic rats were orally administrated Corni Fructus (CF) extract at 300 mg/kg or metformin at 250 mg/kg daily for 4 weeks. Blood glucose and triglyceride (TG) in sera and urine total volume were measured. Histopathological changes of different organs, pancreas, liver, kidney, and lung tissues were observed by H&E staining. The expression of insulin and α-smooth muscle actin (α-SMA) was investigated in pancreas, and kidney by immunohistochemistry, respectively. The results revealed that CF extract significantly decreased the serum levels of blood glucose, and TG, and also urine total volume in STZ-induced diabetic rats. The histological examinations revealed amelioration of diabetes-induced pancreas injury including pathological changes of the Langerhans's islet and glomerular with their loss after the administration of CF extraction. Moreover, the administration of CF extract increased the numbers of insulin releasing beta cells in pancreas and also inhibited the expression of α-SMA in kidney of STZ-induced diabetic rats. On the other hand, CF extract showed no effect on the pathological damages of liver and lung in STZ-induced diabetic rats. These results demonstrated that CF extract may have a selective therapeutic potential through the control of hyperglycemia, and the protection of pancreas and kidney against diabetic damage.
Examples of enhanced quantization: Bosons, fermions and anyons
Authors: Adorno T. C. , Klauder J. R.
Published: August 2014

Enhanced quantization offers a different classical/quantum connection than that of canonical quantization in which ℏ > 0 throughout. This result arises when the only allowed Hilbert space vectors allowed in the quantum action functional are coherent states, which leads to the classical action functional augmented by additional terms of order ℏ. Canonical coherent states are defined by unitary transformations of a fixed, fiducial vector. While Gaussian vectors are commonly used as fiducial vectors, they cannot be used for all systems. We focus on choosing fiducial vectors for several systems including bosons, fermions and anyons.
LP Shilnikov 1934–2011: A Tribute From 'The West'
Authors: Champneys Alan R.
Published: August 2014

This article presents a tribute to L. P. Shilnikov from a fan, a scientist from the next generation who owes much of his career to the results pioneered by this truly great man. The discourse is based on a mixture of personal recollections and conversations with a number of key individuals.
Simple Scenarios of Onset of Chaos in Three-Dimensional Maps
Authors: Gonchenko Alexander , Gonchenko Sergey , Kazakov Alexey , Turaev Dmitry
Published: August 2014

We give a qualitative description of two main routes to chaos in three-dimensional maps. We discuss Shilnikov scenario of transition to spiral chaos and a scenario of transition to discrete Lorenz-like and figure-eight strange attractors. The theory is illustrated by numerical analysis of three-dimensional Henon-like maps and Poincaré maps in models of nonholonomic mechanics.
Shilnikov Chaos in Oscillators with Huygens Coupling
Authors: Belykh Vladimir N. , Pankratova Evgeniya V.
Published: August 2014

We consider van der Pol–Duffing oscillators coupled via a two-dimensional linear system, representing Huygens coupling. We demonstrate that two identical synchronized oscillators can have chaotic movements and exhibit Shilnikov chaos. We rigorously prove the existence of a homoclinic orbit of a saddle-focus and a symmetrical heteroclinic contour of two saddle-foci, leading to the appearance of chaos via the Shilnikov saddle-focus bifurcation. We also support our analytical results with numerical simulations, revealing the main signature of Shilnikov chaos, the coexistence of chaotic and regular attractors with riddled basins of attraction, including wild attractors.
Dynamics of the Logistic Equation with Delay and Delay Control
Authors: Kashchenko S. A.
Published: August 2014

Asymptotic methods investigate the dynamic properties of the logistic equation with delay and delay control. The possibility to effectively control the characteristics of the relaxation cycle has been illustrated. We introduce a new method of studying the dynamics, provided that the ratio of the delayed control is large enough. The original problem of the dynamics equation with delays has been reduced to the nonlocal special dynamics of nonlinear boundary-value problems of a parabolic type.
Periodic Solutions with a Boundary Layer of Reaction–Diffusion Equations with Singularly Perturbed Neumann Boundary Conditions
Authors: Butuzov Valentin F. , Nefedov Nikolay N. , Recke Lutz , Schneider Klaus R.
Published: August 2014

We consider singularly perturbed reaction–diffusion equations with singularly perturbed Neumann boundary conditions. We establish the existence of a time-periodic solution u(x, t, ε) with boundary layers and derive conditions for their asymptotic stability. The boundary layer part of u(x, t, ε) is of order one, which distinguishes our case from the case of regularly perturbed Neumann boundary conditions, where the boundary layer is of order ε. Another peculiarity of our problem is that — in contrast to the case of Dirichlet boundary conditions — it may have several asymptotically stable time-periodic solutions, where these solutions differ only in the description of the boundary layers. Our approach is based on the construction of sufficiently precise lower and upper solutions.
Finite rigid sets and homologically nontrivial spheres in the curve complex of a surface
Authors: Birman Joan , Broaddus Nathan , Menasco William
Published: August 2014

Aramayona and Leininger have provided a "finite rigid subset" 𝔛(Σ) of the curve complex [Formula: see text] of a surface [Formula: see text], characterized by the fact that any simplicial injection [Formula: see text] is induced by a unique element of the mapping class group Mod(Σ). In this paper we prove that, in the case of the sphere with n ≥ 5 marked points, the reduced homology class of the finite rigid set of Aramayona and Leininger is a Mod(Σ)-module generator for the reduced homology of the curve complex [Formula: see text], answering in the affirmative a question posed in [1]. For the surface [Formula: see text] with g ≥ 3 and n ∈ {0, 1} we find that the finite rigid set 𝔛(Σ) of Aramayona and Leininger contains a proper subcomplex X(Σ) whose reduced homology class is a Mod(Σ)-module generator for the reduced homology of [Formula: see text] but which is not itself rigid.
Cohomology of deformations
Authors: Bader Uri , Nowak Piotr W.
Published: August 2014

In this paper we study cohomology of a group with coefficients in representations on Banach spaces and its stability under deformations. We show that small, metric deformations of the representation preserve vanishing of cohomology. As applications we obtain deformation theorems for fixed point properties on Banach spaces. In particular, our results yield fixed point theorems for affine actions in which the linear part is not uniformly bounded. Our proofs are effective and allow for quantitative estimates.
On the theory and application of one-step numerical schemes for solving quantum stochastic differential equation (QSDE)
Authors: Akinwumi T. O. , Adegboyegun B. J.
Published: August 2014

This paper presents one-step numerical schemes for solving quantum stochastic differential equation (QSDE). The algorithms are developed based on the definition of QSDE and the solution techniques yield rapidly convergent sequences which are readily computable. As well as developing the schemes, we perform some numerical experiments and the solutions obtained compete favorably with exact solutions. The solution techniques presented in this work can handle all class of QSDEs most especially when the exact solution does not exist.
On the bound of the complexity of the normal basis generated by the trace of the dual element of a Type I optimal normal element
Authors: Mishra Alok , Sharma Rajendra Kumar , Shukla Wagish
Published: August 2014

Let 𝔽q be a finite field and 𝔽qn be an extension, where a Type I optimal normal basis exists. Suppose n = mk. We provide a bound for the complexity of the normal basis of 𝔽qm over 𝔽q generated by the trace of the dual element of the generator of a Type I optimal normal basis of 𝔽qn over 𝔽q. Further, we show that our bounds are better than the known bounds under certain conditions on m and k.
Partial sum of generalized class of meromorphically univalent functions defined by q-analogue of Liu–Srivastava operator
Authors: Aldweby Huda , Darus Maslina
Published: August 2014

In this paper, we introduce a subclass of meromorphically univalent functions involving q-hypergeometric function. We derive results based on partial sums of functions belonging to this class.
Asymptotics in weighted corner spaces
Authors: Lyu Xiaojing
Published: August 2014

We study corner spaces on singular manifolds, in particular, with conical or edge singularities, and singularities of second-order. We characterize the nature of discrete asymptotics, and we establish other elements of the analysis in these spaces which are necessary in the corner pseudo-differential calculus.
The impact of free cash flows and agency costs on firm performance — An empirical analysis of KSE listed companies of Pakistan
Authors: Khidmat Waqas Bin , Rehman Mobeen Ur
Published: August 2014

The purpose of this research is to find out the impact of free cash flows and agency costs on firm performance in KSE listed companies of Pakistan. A sample of 123 companies listed on KSE representing eight different sectors has been analyzed to determine the association of free cash flows, agency costs and firm performance with each other. For the purpose of analysis, secondary data of selected companies for the period 2003–2009 has been taken from balance sheet analysis of joint stock companies (BSA) issued by State Bank of Pakistan (SBP). Free cash flows have been calculated as by Poulsen (1993) and Lang et al. (1991) while four proxy variables for agency costs are used (Wang, 2010) to assess their relationship with each other and with the firm performance. Results showed that there is a significantly positive relationship between free cash flows and agency cost. Free cash flows have significantly negative impacts on firm performance. The study also shows a significantly negative impact of agency cost on firm performance with exception to total asset turnover (TATO) ratio which has a positive impact. In Pakistani context, the minority shareholders are exploited by the majority shareholders and the management so the government with the help of this study can devise such rules of corporate governance in which the agency cost can be controlled. The investors also are benefitted from this study as they can efficiently manage their portfolio while looking at the impacts of agency costs and firms free cash flows. So this study enables us to better understand the linkage between agency cost, free cash flows and performance measures.
Adaptive Parallelism Exploitation under Physical and Real-Time Constraints for Resilient Systems
Authors: Itturiet Fábio , Nazar Gabriel , Ferreira Ronaldo , Moreira Álvaro , Carro Luigi
Published: August 2014

This article introduces the resilient adaptive algebraic architecture that aims at adapting parallelism exploitation of a matrix multiplication algorithm in a time-deterministic fashion to reduce power consumption while meeting real-time deadlines present in most DSP-like applications. The proposed architecture provides low-overhead error correction capabilities relying on the hardware implementation of the algorithm-based fault-tolerance method that is executed concurrently with matrix multiplication, providing efficient occupation of memory and power resources. The Resilient Adaptive Algebraic Architecture (RA
3
) is evaluated using three real-time industrial case studies from the telecom and multimedia application domains to present the design space exploration and the adaptation possibilities the architecture offers to hardware designers. RA
3
is compared in its performance and energy efficiency with standard high-performance architectures, namely a GPU and an out-of-order general-purpose processor. Finally, we present the results of fault injection campaigns in order to measure the architecture resilience to soft errors.
Road-RFSense: A Practical RF Sensing--Based Road Traffic Estimation System for Developing Regions
Authors: Sen Rijurekha , Maurya Abhinav , Raman Bhaskaran , Mehta Rupesh , Kalyanaraman Ramkrishnan , Singh Amarjeet
Published: August 2014

An unprecedented rate of growth in the number of vehicles has resulted in acute road congestion problems worldwide, especially in many developing countries. In this article, we present Road-RFSense, a practical RF sensing--based road traffic estimation system for developing regions. Our first contribution is a new mechanism to sense road occupancy, based on variation in RF link characteristics, when line of sight between a transmitter-receiver pair is obstructed. We design algorithms to classify traffic states into two classes, free-flow versus congested, at timescales of 20 seconds with greater than 90% accuracy.

We also present a traffic queue length measurement system, where a network of RF sensors can correlate the traffic state classification decisions of individual sensors and detect traffic queue length in real time. Deployment of our system on a Mumbai road gives correct estimates, validated against 9 hours of image-based ground truth. Our third contribution is a large-scale data-driven study, in collaboration with city traffic authorities, to answer questions regarding road-specific classification model training. Finally, we explore multilevel classification into seven different traffic states using a larger set of RF-based features and careful choice of classification algorithms.
PROPANE
Authors: Pazzi Richard W. , Boukerche Azzedine
Published: August 2014

Image-Based Rendering (IBR) has become widely known by its relatively low requirements for generating new scenes based on a sequence of reference images. This characteristic of IBR shows a remarkable potential impact in rendering complex 3D virtual environments on graphics-constrained devices, such as head-mounted displays, set-top boxes, media streaming devices, and so on. If well exploited, IBR coupled with remote rendering would enable the exploration of complex virtual environments on these devices. However, remote rendering requires the transmission of a large volume of images. In addition, existing solutions consider limited and/or deterministic navigation schemes as a means of decreasing the volume of streamed data. This article proposes the
PRO
gressive
PAN
orama Str
E
aming protocol (PROPANE) to offer users a smoother virtual navigation experience by prestreaming the imagery data required to generate new views as the user wanders within a 3D environment. PROPANE is based on a very simple yet effective trigonometry model and uses a
strafe
(lateral movement) technique to minimize the delay between image updates at the client end. This article introduces the concept of key partial panoramas, namely panorama segments that cover movements in any direction by simply
strafing
from an appropriate key partial panorama and streaming the amount of lost pixels. Therefore, PROPANE can provide a constrained device with sufficient imagery data to cover a future user's viewpoints, thereby minimizing the impact of transmission delay and jitter. PROPANE has been implemented and compared to two baseline remote rendering schemes. The evaluation results show that the proposed technique outperforms the selected and closely related existing schemes by minimizing the response time while not limiting the user to predefined paths as opposed to previous protocols.
Up-Fusion
Authors: Wang Xiangyu , Rui Yong , Kankanhalli Mohan
Published: August 2014

The amount of multimedia data on the Internet has increased exponentially in the past few decades and this trend is likely to continue. Multimedia content inherently has multiple information sources, therefore effective fusion methods are critical for data analysis and understanding. So far, most of the existing fusion methods are static with respect to time, making it difficult for them to handle the evolving multimedia content. To address this issue, in recent years, several evolving fusion methods were proposed, however, their requirements are difficult to meet, making them useful only in limited applications. In this article, we propose a novel evolving fusion method based on the online portfolio selection theory. The proposed method takes into account the correlation among different information sources and evolves the fusion model when new multimedia data is added. It performs effectively on both crisp and soft decisions without requiring additional context information. Extensive experiments on concept detection and human detection tasks over the TRECVID dataset and surveillance data have been conducted and significantly better performance has been obtained.
Networks-on-Chip for FPGAs
Authors: Abdelfattah Mohamed S. , Betz Vaughn
Published: August 2014

As FPGA capacity increases, a growing challenge is connecting ever-more components with the current low-level FPGA interconnect while keeping designers productive and on-chip communication efficient. We propose augmenting FPGAs with networks-on-chip (NoCs) to simplify design, and we show that this can be done while maintaining or even improving silicon efficiency. We compare the area and speed efficiency of each NoC component when implemented hard versus soft to explore the space and inform our design choices. We then build on this component-level analysis to architect hard NoCs and integrate them into the FPGA fabric; these NoCs are on average 20--23× smaller and 5--6× faster than soft NoCs. A 64-node hard NoC uses only ∼2% of an FPGA's silicon area and metallization. We introduce a new communication efficiency metric: silicon area required per realized communication bandwidth. Soft NoCs consume 4960 mm
2
/TBps, but hard NoCs are 84× more efficient at 59 mm
2
/TBps. Informed design can further reduce the area overhead of NoCs to 23 mm
2
/TBps, which is only 2.6× less efficient than the simplest point-to-point soft links (9 mm
2
/TBps). Despite this almost comparable efficiency, NoCs can switch data across the entire FPGA while point-to-point links are very limited in capability; therefore, hard NoCs are expected to improve FPGA efficiency for more complex styles of communication.
Composing Multi-Ported Memories on FPGAs
Authors: Laforest Charles Eric , Li Zimo , O'rourke Tristan , Liu Ming G. , Steffan J. Gregory
Published: August 2014

Multi-ported memories are challenging to implement on FPGAs since the block RAMs included in the fabric typically have only two ports. Hence we must construct memories requiring more than two ports, either out of logic elements or by combining multiple block RAMs. We present a thorough exploration and evaluation of the design space of FPGA-based soft multi-ported memories for conventional solutions, and also for the recently proposed Live Value Table (LVT) [LaForest and Steffan 2010] and XOR [LaForest et al. 2012] approaches to unidirectional port memories, reporting results for both Altera and Xilinx FPGAs. Additionally, we thoroughly evaluate and compare with a recent LVT-based approach to bidirectional port memories [Choi et al. 2012].
On the Performance of Lossy Compression Schemes for Energy Constrained Sensor Networking
Authors: Zordan Davide , Martinez Borja , Vilajosana Ignasi , Rossi Michele
Published: August 2014

Lossy temporal compression is key for energy-constrained wireless sensor networks (WSNs), where the imperfect reconstruction of the signal is often acceptable at the data collector, subject to some maximum error tolerance. In this article, we evaluate a number of selected lossy compression methods from the literature and extensively analyze their performance in terms of compression efficiency, computational complexity, and energy consumption. Specifically, we first carry out a performance evaluation of existing and new compression schemes, considering linear, autoregressive, FFT-/DCT- and wavelet-based models , by looking at their performance as a function of relevant signal statistics. Second, we obtain formulas through numerical fittings to gauge their overall energy consumption and signal representation accuracy. Third, we evaluate the benefits that lossy compression methods bring about in interference-limited multihop networks, where the channel access is a source of inefficiency due to collisions and transmission scheduling. Our results reveal that the DCT-based schemes are the best option in terms of compression efficiency but are inefficient in terms of energy consumption. Instead, linear methods lead to substantial savings in terms of energy expenditure by, at the same time, leading to satisfactory compression ratios, reduced network delay, and increased reliability performance.
An Evaluation of High-Level Mechanistic Core Models
Authors: Carlson Trevor E. , Heirman Wim , Eyerman Stijn , Hur Ibrahim , Eeckhout Lieven
Published: August 2014

Large core counts and complex cache hierarchies are increasing the burden placed on commonly used simulation and modeling techniques. Although analytical models provide fast results, they do not apply to complex, many-core shared-memory systems. In contrast, detailed cycle-level simulation can be accurate but also tends to be slow, which limits the number of configurations that can be evaluated. A middle ground is needed that provides for fast simulation of complex many-core processors while still providing accurate results.

In this article, we explore, analyze, and compare the accuracy and simulation speed of high-abstraction core models as a potential solution to slow cycle-level simulation. We describe a number of enhancements to interval simulation to improve its accuracy while maintaining simulation speed. In addition, we introduce the instruction-window centric (IW-centric) core model, a new mechanistic core model that bridges the gap between interval simulation and cycle-accurate simulation by enabling high-speed simulations with higher levels of detail. We also show that using accurate core models like these are important for memory subsystem studies, and that simple, naive models, like a one-IPC core model, can lead to misleading and incorrect results and conclusions in practical design studies. Validation against real hardware shows good accuracy, with an average single-core error of 11.1% and a maximum of 18.8% for the IW-centric model with a 1.5× slowdown compared to interval simulation.
Placing Sensors for Area Coverage in a Complex Environment by a Team of Robots
Authors: Li Xu , Fletcher Greg , Nayak Amiya , Stojmenovic Ivan
Published: August 2014

Existing solutions to carrier-based sensor placement by a single robot in a bounded unknown Region of Interest (ROI) do not guarantee full area coverage or termination. We propose a novel localized algorithm, named
Back-Tracking Deployment
(BTD). To construct a full coverage solution over the ROI, mobile robots (carriers) carry static sensors as payloads and drop them at the visited empty vertices of a virtual square, triangular, or hexagonal grid. A single robot will move in a predefined order of directional preference until a dead end is reached. Then it back-tracks to the nearest sensor adjacent to an empty vertex (an “entrance” to an unexplored/uncovered area) and resumes regular forward movement and sensor dropping from there. To save movement steps, the back-tracking is carried out along a locally identified shortcut. We extend the algorithm to support multiple robots that move independently and asynchronously. Once a robot reaches a dead end, it will back-track, giving preference to its own path. Otherwise, it will take over the back-track path of another robot by consulting with neighboring sensors. We prove that BTD terminates within finite time and produces full coverage when no (sensor or robot) failures occur. We also describe an approach to tolerate failures and an approach to balance workload among robots. We then evaluate BTD in comparison with the only competing algorithms SLD [Chang et al. 2009a] and LRV [Batalin and Sukhatme 2004] through simulation. In a specific failure-free scenario, SLD covers only 40--50% of the ROI, whereas BTD covers it in full. BTD involves significantly (80%) less robot moves and messages than LRV.
A Top-Down Approach for Video Summarization
Authors: Guan Genliang , Wang Zhiyong , Mei Shaohui , Ott Max , He Mingyi , Feng David Dagan
Published: August 2014

While most existing video summarization approaches aim to identify important frames of a video from either a global or local perspective, we propose a top-down approach consisting of scene identification and scene summarization. For scene identification, we represent each frame with global features and utilize a scalable clustering method. We then formulate scene summarization as choosing those frames that best cover a set of local descriptors with minimal redundancy. In addition, we develop a visual word-based approach to make our approach more computationally scalable. Experimental results on two benchmark datasets demonstrate that our proposed approach clearly outperforms the state-of-the-art.
Online Estimation of Evolving Human Visual Interest
Authors: Katti Harish , Rajagopal Anoop Kolar , Kankanhalli Mohan , Kalpathi Ramakrishnan
Published: August 2014

Regions in video streams attracting human interest contribute significantly to human understanding of the video. Being able to predict
salient
and informative Regions of Interest (ROIs) through a sequence of eye movements is a challenging problem. Applications such as content-aware retargeting of videos to different aspect ratios while preserving informative regions and smart insertion of dialog (closed-caption text)
1
into the video stream can significantly be improved using the predicted ROIs. We propose an interactive human-in-the-loop framework to model eye movements and predict visual saliency into yet-unseen frames. Eye tracking and video content are used to model visual attention in a manner that accounts for important eye-gaze characteristics such as temporal discontinuities due to sudden eye movements, noise, and behavioral artifacts. A novel statistical- and algorithm-based method
gaze buffering
is proposed for eye-gaze analysis and its fusion with content-based features. Our robust saliency prediction is instantiated for two challenging and exciting applications. The first application alters video aspect ratios on-the-fly using content-aware video retargeting, thus making them suitable for a variety of display sizes. The second application dynamically localizes active speakers and places dialog captions on-the-fly in the video stream. Our method ensures that dialogs are faithful to active speaker locations and do not interfere with salient content in the video stream. Our framework naturally accommodates personalisation of the application to suit biases and preferences of individual users.
(Leveled) Fully Homomorphic Encryption without Bootstrapping
Authors: Brakerski Zvika , Gentry Craig , Vaikuntanathan Vinod
Published: August 2014

We present a novel approach to fully homomorphic encryption (FHE) that dramatically improves performance and bases security on weaker assumptions. A central conceptual contribution in our work is a new way of constructing leveled, fully homomorphic encryption schemes (capable of evaluating arbitrary polynomial-size circuits of a-priori bounded depth), without Gentry’s bootstrapping procedure.

Specifically, we offer a choice of FHE schemes based on the learning with error (LWE) or Ring LWE (RLWE) problems that have 2
λ
security against known attacks. We construct the following.

(1) A leveled FHE scheme that can evaluate depth-
L
arithmetic circuits (composed of fan-in 2 gates) using
O
(
λ
.
L
3) per-gate computation, quasilinear in the security parameter. Security is based on RLWE for an approximation factor exponential in
L
. This construction does not use the bootstrapping procedure.

(2) A leveled FHE scheme that can evaluate depth-
L
arithmetic circuits (composed of fan-in 2 gates) using
O
(
λ
2) per-gate computation, which is independent of
L
. Security is based on RLWE for quasipolynomial factors. This construction uses bootstrapping as an optimization.

We obtain similar results for LWE, but with worse performance. All previous (leveled) FHE schemes required a per-gate computation of
Ω
(
λ
3.5), and all of them relied on subexponential hardness assumptions.

We introduce a number of further optimizations to our scheme based on the Ring LWE assumption. As an example, for circuits of large width (e.g., where a constant fraction of levels have width
Ω
(
λ
)), we can reduce the per-gate computation of the bootstrapped version to
O
(
λ
), independent of
L
, by batching the bootstrapping operation. At the core of our construction is a new approach for managing the noise in lattice-based ciphertexts, significantly extending the techniques of Brakerski and Vaikuntanathan [2011b].
Better Scalable Algorithms for Broadcast Scheduling
Authors: Bansal Nikhil , Krishnaswamy Ravishankar , Nagarajan Viswanath
Published: August 2014

In the classical
broadcast scheduling problem
, there are
n
pages stored at a server, and requests for these pages arrive over time. Whenever a page is broadcast, it satisfies all outstanding requests for that page. The objective is to minimize average
flow time
of the requests. For any ϵ > 0, we give a (1+ϵ)-speed
O
(1/ϵ
3
)-competitive online algorithm for broadcast scheduling. This improves over the recent breakthrough result of Im and Moseley [2010], where they obtained a (1+ϵ)-speed
O
(1/ϵ
11
)-competitive algorithm. Our algorithm and analysis are considerably simpler than Im and Moseley [2010]. More importantly, our techniques also extend to the general setting of
nonuniform page sizes
and
dependent requests
. This is the first scalable algorithm for broadcast scheduling with varying size pages and resolves the main open question from Im and Moseley [2010].
Constraint Solving via Fractional Edge Covers
Authors: Grohe Martin , Marx Dániel
Published: August 2014

Many important combinatorial problems can be modeled as constraint satisfaction problems. Hence, identifying polynomial-time solvable classes of constraint satisfaction problems has received a lot of attention. In this article, we are interested in structural properties that can make the problem tractable. So far, the largest structural class that is known to be polynomial-time solvable is the class of bounded hypertree width instances introduced by Gottlob et al. [2002]. Here we identify a new class of polynomial-time solvable instances: those having bounded fractional edge cover number. Combining hypertree width and fractional edge cover number, we then introduce the notion of fractional hypertree width. We prove that constraint satisfaction problems with bounded fractional hypertree width can be solved in polynomial time (provided that the tree decomposition is given in the input). Together with a recent approximation algorithm for finding such decompositions [Marx 2010], it follows that bounded fractional hypertree width is now the most generally known structural property that guarantees polynomial-time solvability.
Approximation Algorithms for Min-Max Generalization Problems
Authors: Berman Piotr , Raskhodnikova Sofya
Published: August 2014

We provide improved approximation algorithms for the
min-max generalization problems
considered by Du, Eppstein, Goodrich, and Lueker [Du et al. 2009]. Generalization is widely used in privacy-preserving data mining and can also be viewed as a natural way of compressing a dataset. In min-max generalization problems, the input consists of data items with weights and a lower bound
w
lb
, and the goal is to partition individual items into groups of weight at least
w
lb
while minimizing the maximum weight of a group. The rules of legal partitioning are specific to a problem. Du et al. consider several problems in this vein: (1) partitioning a graph into connected subgraphs, (2) partitioning unstructured data into arbitrary classes, and (3) partitioning a two-dimensional array into contiguous rectangles (subarrays) that satisfy these weight requirements.

We significantly improve approximation ratios for all the problems considered by Du et al. and provide additional motivation for these problems. Moreover, for the first problem, whereas Du et al. give approximation algorithms for specific graph families, namely, 3-connected and 4-connected planar graphs, no approximation algorithm that works for all graphs was known prior to this work.
Annotations in Data Streams
Authors: Chakrabarti Amit , Cormode Graham , Mcgregor Andrew , Thaler Justin
Published: August 2014

The central goal of data stream algorithms is to process massive streams of data using
sublinear
storage space. Motivated by work in the database community on outsourcing database and data stream processing, we ask whether the space usage of such algorithms can be further reduced by enlisting a more powerful “helper” that can
annotate
the stream as it is read. We do not wish to blindly trust the helper, so we require that the algorithm be convinced of having computed a correct answer. We show upper bounds that achieve a nontrivial tradeoff between the amount of annotation used and the space required to verify it. We also prove lower bounds on such tradeoffs, often nearly matching the upper bounds, via notions related to Merlin-Arthur communication complexity. Our results cover the classic data stream problems of selection, frequency moments, and fundamental graph problems such as triangle-freeness and connectivity. Our work is also part of a growing trend—including recent studies of multipass streaming, read/write streams, and randomly ordered streams—of asking more complexity-theoretic questions about data stream processing. It is a recognition that, in addition to practical relevance, the data stream model raises many interesting theoretical questions in its own right.
PDGF receptor-α promotes TGF-β signaling in hepatic stellate cells via transcriptional and posttranscriptional regulation of TGF-β receptors
Authors: Liu Chunsheng , Li Jiachu , Xiang Xiaoyu , Guo Luyang , Tu Kangsheng , Liu Qinghua , Shah Vijay H. , Kang Ningling
Published: August 2014

Platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β) signaling are required for hepatic stellate cell (HSC) activation under pathological conditions such as liver metastatic tumor growth. These two signaling pathways are functionally divergent; PDGF signaling promotes proliferation and migration of HSCs, and TGF-β induces transdifferentiation of quiescent HSCs into myofibroblasts. Although PDGF signaling is implicated in TGF-β-mediated epithelial mesenchymal transition of tumor cells, the role of PDGF receptors in TGF-β activation of HSCs has not been investigated. Here we report that PDGF receptor-α (PDGFR-α) is required for TGF-β signaling of cultured human HSCs although HSCs express both PDGF-α and -β receptors. PDGFR-α knockdown inhibits TGF-β-induced phosphorylation and nuclear accumulation of SMAD2 with no influence on AKT or ERK phosphorylation associated with noncanonical TGF-β signaling. PDGFR-α knockdown suppresses TGF-β receptor I (TβRI) but increases TβRII gene transcription. At the protein level, PDGFR-α is recruited to TβRI/TβRII complexes by TGF-β stimulation. PDGFR-α knockdown blocks TGF-β-mediated internalization of TβRII and induces accumulation of TβRII at the plasma membrane, thereby inhibiting TGF-β phosphorylation of SMAD2. Functionally, knockdown of PDGFR-α reduces paracrine effects of HSCs on colorectal cancer cell proliferation and migration in vitro. In mice and patients, colorectal cancer cell invasion of the liver induces upregulation of PDGFR-α of HSCs. In summary, our finding that PDGFR-α knockdown inhibits SMAD-dependent TGF-β signaling by repressing TβRI transcriptionally and blocking endocytosis of TGF-β receptors highlights a convergence of PDGF and TGF-β signaling for HSC activation and PDGFR-α as a therapeutic target for liver metastasis and other settings of HSC activation.
Dicer mediating the expression of miR-143 and miR-155 regulates hexokinase II associated cellular response to hypoxia
Authors: Yao Mengying , Wang Xinhua , Tang Ying , Zhang Weihong , Cui Bing , Liu Qiuhong , Xing Lihua
Published: August 2014

Lung alveolar epithelial cells are exposed to hypoxia under a variety of physiological and pathological conditions. It has been shown recently that miR-143, which can directly target the key glycolytic enzyme hexokinase II (HK2), may be regulated by miR-155. We investigated whether microRNAs contribute to the cellular glycolysis in response to hypoxia. Using the A549 cells, we found that the expression of Dicer is decreased under hypoxia. When Dicer was knocked down with small-interfering RNA (siRNA), pre-miR143 was increased and mature miR-143 was decreased as that in hypoxia, indicating that reduction of Dicer is responsible for the change of miR-143 under hypoxia. Interestingly, both hypoxia and knockdown of Dicer resulted in miR-155 and pre-miR-155 expression increases. We also examined the expression of HK2 and glucose metabolism in the cells. Both HK2 mRNA and protein were increased under hypoxia, which is accompanied by an increase of glucose uptake and production of lactate. The same alterations were found with siRNA Dicer knockdown. Moreover, transfection with anti-miR-143 also led to a HK2 production and an increase of glucose uptake and lactate production, whereas anti-miR-155 had opposite effects. The miR-143 and anti-miR-155 transfection resulted in a significant cell apoptosis. The expression of Dicer was decreased with HK2 accumulating in mouse lung tissues under hypoxia identified by immunohistochemistry. The changes of miR-143 and miR-155 were similar to those in A549 cells. Our data demonstrate that Dicer regulation of miRNAs promotes HK2 activation and glycolysis, which might protect the cell from hypoxic damage and enter into an adaptive process.
Pendelluft in the bronchial tree
Authors: Greenblatt Elliot E. , Butler James P. , Venegas Jose G. , Winkler Tilo
Published: August 2014

Inhomogeneous inflation or deflation of the lungs can cause dynamic pressure differences between regions and lead to interregional airflows known as pendelluft. This work first uses analytical tools to clarify the theoretical limits of pendelluft at a single bifurcation. It then explores the global and regional pendelluft that may occur throughout the bronchial tree in a realistic example using an in silico model of bronchoconstriction. The theoretical limits of pendelluft volume exchanged at a local bifurcation driven by sinusoidal breathing range from 15.5% to 41.4% depending on the relative stiffness of the subtended regions. When nonsinusoidal flows are considered, pendelluft can be as high as 200% inlet tidal volume (Vin). At frequencies greater than 10 Hz, the inertia of the air in the airways becomes important, and the maximal local pendelluft is theoretically unbounded, even with sinusoidal breathing. In a single illustrative numerical simulation of bronchoconstriction with homogenous compliances, the overall magnitude of global pendelluft volume was <2% of the tidal volume. Despite the small overall magnitude, pendelluft volume exchange was concentrated in poorly ventilated regions of the lung, including local pendelluft at bifurcations of up to 13% Vin. This example suggests that pendelluft may be an important phenomena contributing to regional gas exchange, irreversible mixing, and aerosol deposition patterns inside poorly ventilated regions of the lung. The analytical results support the concept that pendelluft may be more prominent in diseases with significant heterogeneity in both resistance and compliance.
Beyond DNA Repair: DNA-PK Function in Cancer
Authors: Goodwin Jonathan F. , Knudsen Karen E.
Published: August 2014

The DNA-dependent protein kinase (DNA-PK) is a pivotal component of the DNA repair machinery that governs the response to DNA damage, serving to maintain genome integrity. However, the DNA-PK kinase component was initially isolated with transcriptional complexes, and recent findings have illuminated the impact of DNA-PK–mediated transcriptional regulation on tumor progression and therapeutic response. DNA-PK expression has also been correlated with poor outcome in selected tumor types, further underscoring the importance of understanding its role in disease. Herein, the molecular and cellular consequences of DNA-PK are considered, with an eye toward discerning the rationale for therapeutic targeting of DNA-PK.

Significance: Although DNA-PK is classically considered a component of damage response, recent findings illuminate damage-independent functions of DNA-PK that affect multiple tumor-associated pathways and provide a rationale for the development of novel therapeutic strategies. Cancer Discov; 4(10); 1126–39. ©2014 AACR.
Intravenous Injection of MVA Virus Targets CD8+ Lymphocytes to Tumors to Control Tumor Growth upon Combinatorial Treatment with a TLR9 Agonist
Authors: Fend Laetitia , Gatard-Scheikl Tanja , Kintz Jacqueline , Gantzer Murielle , Schaedler Emmanuelle , Rittner Karola , Cochin Sandrine , Fournel Sylvie , Préville Xavier
Published: August 2014

Effector T-cell access to tumor tissue is a limiting step for clinical efficacy of antigen-specific T cell–based immunotherapies. Ectopic mouse tumor models, in which a subcutaneously (s.c.) implanted tumor is treated with s.c. or intramuscular therapeutic immunization, may not be optimal for targeting effector T cells to an organ-borne tumor. We used an orthotopic renal carcinoma model to evaluate the impact of injection routes on therapeutic efficacy of a Modified Vaccinia virus Ankara viral vector expressing the human mucin 1 tumor–associated xeno-antigen (MVA-MUC1). We show that intravenous (i.v.) administration of MVA-MUC1 displayed enhanced efficacy when compared with s.c. injection. Therapeutic efficacy of MVA-MUC1 was further enhanced by i.v. injection of a TLR9 agonist. In all cases, infiltration of tumor-bearing kidney by CD8+ lymphocytes was associated with control of tumor growth. Biodistribution experiments indicate that, following i.v. injection, MVA-encoded antigens are quickly expressed in visceral organs and, in particular, in splenic antigen-presenting cells, compared with those following s.c. injection. This appears to result in a faster generation of MUC1-specific CD8+ T cells. Lymphocytes infiltrating tumor-bearing kidneys are characterized by an effector memory phenotype and express PD-1 and Tim3 immune checkpoint molecules. Therapeutic efficacy was associated with a modification of the tumor microenvironment toward a Th1-type immune response and recruitment of activated lymphocytes. This study supports the clinical evaluation of MVA-based immunotherapies via the i.v. route. Cancer Immunol Res; 2(12); 1163–74. ©2014 AACR.
Signaling Pathways in the Specification of Arteries and Veins
Authors: Corada Monica , Morini Marco Francesco , Dejana Elisabetta
Published: August 2014

The establishment of arterial and venous identity of endothelial cells is critical for the proper anatomic configuration and function of the vascular tree. Arterial and venous specification of endothelial cells is determined by genetic factors, although surrounding cells and hemodynamic forces may also contribute to vascular remodeling. This review provides an overview of the signaling pathways and related transcription factors implicated in differentiation of endothelial cells. We will discuss, in particular, the role of upstream and downstream effectors of Wnt, Sox, and Notch pathways. The understanding of the molecular mechanisms that orchestrate endothelial differentiation may have therapeutic relevance for diseases such as atherosclerosis, arteriovenous malformations, aneurysms, and others.
Platelets Are Highly Activated in Patients of Chronic Thromboembolic Pulmonary Hypertension
Authors: Yaoita Nobuhiro , Shirakawa Ryutaro , Fukumoto Yoshihiro , Sugimura Koichiro , Miyata Satoshi , Miura Yutaka , Nochioka Kotaro , Miura Masanobu , Tatebe Shunsuke , Aoki Tatsuo , Yamamoto Saori , Satoh Kimio , Kimura Tomohiro , Shimokawa Hiroaki , Horiuchi Hisanori
Published: August 2014

Objective—

Chronic thromboembolic pulmonary hypertension (CTEPH) is a fatal disease that is distinct from pulmonary arterial hypertension (PAH). Although CTEPH is characterized by obstruction of major pulmonary artery because of chronic thrombus, it remains unclear whether CTEPH is associated with prothrombotic condition.

Approach and Results—

In addition to conventional markers, GTP-bound levels of Rap1, RhoA, RalA, Rac1, and Ras in platelets, which are implicated for platelet activation, were measured in patients without pulmonary hypertension (non-PH, n=15), patients with PAH (n=19), and patients with CTEPH (n=25). Furthermore, the responsiveness to ex vivo thrombin stimulation was also evaluated. The ratios of the P-selectin positive platelets in the non-PH patients, patients with PAH, and patients with CTEPH were 1.40% (median and interquartile range, 0.83–1.82), 2.40% (1.80–3.39), and 2.63% (1.90–8.22), respectively (non-PH versus CTEPH,
P
<0.01). The activated GPIIb/IIIa-positive platelets were 6.01% (1.34–7.87), 11.39% (5.69–20.86), and 9.74% (7.83–24.01), respectively (non-PH versus CTEPH,
P
=0.01). GTP-bound RhoA was 1.79% (0.94–2.83), 4.03% (2.01–5.14), and 2.01% (1.22–2.48), respectively (non-PH versus PAH,
P
=0.04), and GTP-bound RalA was 1.58% (1.08–2.11), 3.02% (2.03–3.54), and 2.64% (1.42–4.28), respectively (non-PH versus PAH,
P
=0.023; non-PH versus CTEPH,
P
=0.048). In contrast, Rac1, Rap1, or Ras was not activated in any groups. The platelets of patients with CTEPH exhibited hyperresponsiveness to ex vivo thrombin stimulation compared with those of non-PH patients when evaluated for the surface markers. Either D-dimer or fibrin degradation product level was not increased in patients with CTEPH.

Conclusions—

These results provide the first direct evidence that platelets of patients with CTEPH are highly activated and exhibit hyperresponsiveness to thrombin stimulation.