bluuebunny/crossref_metadata_2025 huggingface dataset:
Complex rectal and anal canal injuries secondary to unusual blunt perineal trauma
Authors: El Lakis Mustapha A , Rida Khaled , Nakhle Ram , Abi Saad George
Published: October 2014

A 27-year-old woman sustained a trauma to her perineal area when she was ejected from a jet ski while riding on water at high speed. The patient presented to the emergency department with blood streaking from her anal canal. Imaging revealed pneumoperitoneum. Surgical intervention showed complex anal canal and rectal injuries. Primary repair of the injuries was performed. Postoperatively the patient did well and was followed up with no evidence of residual symptoms and with a continent anal sphincter.
Leading a university
Authors: Nolan Andrea
Published: October 2014

Andrea Nolan became the principal and vice‐chancellor of Edinburgh Napier university just over a year ago. She qualified as vet from Trinity College Dublin and, after a spell in practice, she has worked in the universities of Cambridge, Bristol, and the Technical University of Munich. In 1999, she became dean of Glasgow vet school before moving into university‐wide leadership
Examining differences in nutrient intake and dietary quality on weekdays versus weekend days in Canada
Authors: Yang Penny H.W. , Black Jennifer L. , Barr Susan I. , Vatanparast Hassanali
Published: October 2014

This study examined differences in dietary intake on weekdays versus weekends in Canada (n = 34 402) and found that energy intake was 62 ± 23 kcal higher, and dietary quality was slightly lower on weekends (p < 0.05). After energy adjustment, Canadians consumed 66% more alcohol, 10% more cholesterol, and significantly lower intakes of carbohydrates, protein, and most micronutrients (ranging from 2.0%–6.9% lower) on weekends. Findings suggest that Canadians consume a slightly less favourable nutrient profile and poorer dietary quality on weekends.
Sedentary behavior is associated with disability status and walking performance, but not cognitive function, in multiple sclerosis
Authors: Hubbard Elizabeth A. , Motl Robert W.
Published: October 2014

Eighty-two persons with multiple sclerosis wore an accelerometer as a measure of sedentary time (min/day) and completed measures of disability status (self-reported Expanded Disability Status Scale), walking performance (timed 25-foot walk and 6-min walk), and cognitive function (symbol digit modalities test). Accelerometry-measured sedentary time was significantly correlated with disability status scores (r = 0.31, p < 0.01), 6-min walk distance (r = –0.40, p < 0.01), and timed 25-foot walk performance (r = 0.35, p < 0.01), but not cognitive function performance (r = –0.12, p = 0.29).
GA–GHCA model for the optimal design of pumped sewer networks
Authors: Rohani Maryam , Afshar Mohammad Hadi
Published: October 2014

In this paper, a hybrid model, GA–GHCA, composed of the genetic algorithm (GA) and the general hybrid cellular automata (GHCA) is proposed for the efficient and effective optimal design of pumped sewer networks with fixed layout. The GHCA model was recently introduced by the authors with considerable success for the optimal design of sewer networks. Two alternative versions of the GA–GHCA model are proposed. In the first approach, the pump locations and the corresponding pumping heads are decided by the GA model, while the diameter and nodal cover depths of the network pipes are optimally determined by the GHCA model considering the predefined pump locations and their pumping heights defined by the GA. In the second model, however, only the pump locations are decided by the GA model and for each GA individual, the network characteristics including the pipe diameters, pipe nodal cover depths, and the pumping heights at the predefined locations are determined by the GHCA model. The proposed GA–GHCA model is tested against a benchmark example of pumped sewer network and the results are presented and compared to those of the existing methods. The results indicate that the proposed method is more efficient and effective than alternative methods for the optimal design of pumped sewer networks.
A gap analysis of tree species representation in the protected areas of the Canadian boreal forest: applying a new assemblage of digital Forest Resource Inventory data
Authors: Cumming Steven G. , Drever C. Ronnie , Houle Mélina , Cosco John , Racine Pierre , Bayne Erin , Schmiegelow Fiona K.A.
Published: October 2014

We undertook a gap analysis of how protected areas represent the tree-species diversity within the Canadian boreal forest, as measured from Forest Resource Inventory (FRI) maps. We used a new compilation of Forest Resource Inventory designed to support ecological analyses over large areas and across jurisdictional boundaries. The analysis was stratified into four analytical regions determined by terrestrial ecozones. We calculated the relative abundance of species within regions, developed rarity criteria, and evaluated the relative abundances and prevalence of rare species. We characterized representation gaps when the abundance of a tree species in protected areas within an analytical region differed markedly (by more than a factor of 2) from the expectation, calculated as the product of regional abundance and the proportional area protected. Most species were well represented in the most species-diverse region (n = 33), the Boreal Shield in eastern Canada, due apparently to a large number of relatively small protected areas in the southern part of the region. Some marked gaps existed in the more species-depauperate western zones, notably for montane conifers in the Boreal Plains. As is common for species abundance distributions, as few as five species accounted for 90% of total abundance in each zone. Relatively rare species were more numerous. Mostly associated with southern temperate or hemiboreal forests, these reached their highest prevalence and abundance in the managed forests of the Boreal Shield. Our work identified some gaps in representation in the protected areas network of Canada in western Canada, substantiates the use of species distribution mapping based on FRI data to inform conservation planning — including the identification of high conservation biodiversity elements for forest certification — and demonstrates the need for improved vegetation mapping in National Parks.
A comparative study of fatty acid profile and formation of biofilm inGeobacillus gargensisexposed to variable abiotic stress
Authors: Al-Beloshei Noor Essa , Al-Awadhi Husain , Al-Khalaf Rania A. , Afzal Mohammad
Published: October 2014

Understanding bacterial fatty acid (FA) profile has a great taxonomic significance as well as clinical importance for diagnosis issues. Both the composition and nature of membrane FAs change under different nutritional, biotic and (or) abiotic stresses, and environmental stress. Bacteria produce both odd-carbon as well as branched-chain fatty acids (BCFAs). This study was designed to examine the effect of abiotic pressure, including salinity, temperature, pH, and oxinic stress on the growth, development, and FA profile in thermophilic Geobacillus gargensis. Under these stresses, 3 parametric ratios, 2-methyl fatty acids/3-methyl fatty acids (iso-/anteiso-FAs), BCFAs/straight-chain saturated fatty acids (SCSFA), and SCSFAs/straight-chain unsaturated fatty acids (SCUFA), in addition to total lipids affected by variable stresses were measured. Our results indicate that the ratio of total iso-/anteiso-FAs increased at the acidic pH range of 4.1–5.2 and decreased with increasing pH. The reverse was true for salt stress when iso-/anteiso-FAs ratio increased with salt concentration. The BCFAs/SCSFAs and SCSFAs/SCUFAs ratios increased at neutral and alkaline pH and high salt concentration, reduced incubation time, and comparatively high temperature (55–65 °C) of the growth medium. The bacterial total lipid percentage deceased with increasing salt concentration, incubation period, but it increased with temperature. The formation of extracellular polymeric substances was observed under all stress conditions and with the addition of sodium dodecyl sulfate (2 and 5 mmol/L) to the growth medium. The membrane phospholipid composition of the bacterium was analyzed by thin-layer chromatography.
Effects of nonlinear electrodynamics in the magnetic field of a pulsar
Authors: Denisov Dmitry M.
Published: October 2014

The eikonal method was used to construct differential equations for beams of electromagnetic waves in magnetic and gravitational fields of pulsars, according to the nonlinear electrodynamics of the vacuum. Integrating these equations using successive approximations allows us to find the ray equations and a parametric form of the law of motion for these beams’ electromagnetic pulses. It is shown that the electromagnetic pulse passing through the magnetic field of the pulsar propagates as two normal waves, arriving at the detector along two different rays and spending different amounts of time in transit. The angles of rays’ bending because of the nonlinearity of the electrodynamics of the vacuum and the delay time of the electromagnetic signal carried by one normal wave relative to the other normal wave are calculated. The magnitude of these effects is evaluated.
EFFICIENT DETERMINISTIC FINITE AUTOMATA SPLIT-MINIMIZATION DERIVED FROM BRZOZOWSKI'S ALGORITHM
Authors: GARCÍA PEDRO , LÓPEZ DAMIÁN , DE PARGA MANUEL VÁZQUEZ
Published: October 2014

Minimization of deterministic finite automata is a classic problem in Computer Science which is still studied nowadays. In this paper, we relate the different split-minimization methods proposed to date, or to be proposed, and the algorithm due to Brzozowski which has been usually set aside in any classification of DFA minimization algorithms. In our work, we first propose a polynomial minimization method derived from a paper by Champarnaud et al. We also show how the consideration of some efficiency improvements on this algorithm lead to obtain an algorithm similar to Hopcroft's classic algorithm. The results obtained lead us to propose a characterization of the set of possible splitters.
LINEAR CONJUNCTIVE GRAMMARS AND ONE-TURN SYNCHRONIZED ALTERNATING PUSHDOWN AUTOMATA
Authors: AIZIKOWITZ TAMAR , KAMINSKI MICHAEL
Published: October 2014

In this paper we introduce a subfamily of synchronized alternating pushdown automata, one-turn synchronized alternating pushdown automata, which accept the same class of languages as those generated by linear conjunctive grammars. This equivalence of models of computation is analogous to the classical equivalence between one-turn pushdown automata and linear grammars, thus strengthening the claim of synchronized alternating pushdown automata as a natural counterpart of conjunctive grammars.
An intermediate quasi-isometric invariant between subexponential asymptotic dimension growth and Yu's property A
Authors: Oppenheim Izhar
Published: October 2014

We present a new quasi-isometric invariant for metric spaces that we name asymptotically large depth. For finitely generated groups we show that this invariant implies Yu's property A and is implied by subexponential asymptotic dimension growth.
Quantum channels in quantum gravity
Authors: Rangamani Mukund , Rota Massimilliano
Published: October 2014

The black hole final state proposal implements manifest unitarity in the process of black hole formation and evaporation in quantum gravity, by postulating a unique final state boundary condition at the singularity. We argue that this proposal can be embedded in the gauge/gravity context by invoking a path integral formalism inspired by the Schwinger–Keldysh like thermo-field double construction in the dual field theory. This allows us to realize the gravitational quantum channels for information retrieval to specific deformations of the field theory path integrals and opens up new connections between geometry and information theory.
A new spin on black hole hair
Authors: Herdeiro Carlos A. R. , Radu Eugen
Published: October 2014

We show that scalar hair can be added to rotating, vacuum black holes (BHs) of general relativity. These hairy black holes (HBHs) clarify a lingering question concerning gravitational solitons: Whether a BH can be added at the centre of a boson star (BS), as it typically can for other solitons. We argue that it can, but only if it is spinning. The existence of such HBHs is related to the Kerr superradiant instability triggered by a massive scalar field. This connection leads to the following conjecture: a (hairless) BH, which is afflicted by the superradiant instability of a given field, must allow hairy generalizations with that field.
Matter may matter
Authors: Haghani Zahra , Harko Tiberiu , Sepangi Hamid Reza , Shahidi Shahab
Published: October 2014

We propose a gravitational theory in which the effective Lagrangian of the gravitational field is given by an arbitrary function of the Ricci scalar, the trace of the matter energy–momentum tensor, and the contraction of the Ricci tensor with the matter energy–momentum tensor. The matter energy–momentum tensor is generally not conserved, thus leading to the appearance of an extra-force, acting on massive particles in a gravitational field. The stability conditions of the theory with respect to local perturbations are also obtained. The cosmological implications of the theory are investigated, representing an exponential solution. Hence, a Ricci tensor–energy–momentum tensor coupling may explain the recent acceleration of the universe, without resorting to the mysterious dark energy.
Universal horizons and black holes in gravitational theories with broken Lorentz symmetry
Authors: Lin Kai , Abdalla Elcio , Cai Rong-Gen , Wang Anzhong
Published: October 2014

In this paper, we first show that the definition of the universal horizons studied recently in the khronometric theory of gravity can be straightforwardly generalized to other theories that violate the Lorentz symmetry, by simply considering the khronon as a probe field and playing the same role as a Killing vector field. As an application, we study static charged (D + 1)-dimensional spacetimes in the framework of the healthy (nonprojectable) Horava–Lifshitz (HL) gravity in the infrared (IR) limit, and find various solutions. Some of them represent Lifshitz spacetimes with hyperscaling violations, and some have black hole structures. In the latter, universal horizons always exist inside the Killing horizons. The surface gravity on them can be either larger or smaller than the surface gravity on the Killing horizons, depending on the spacetimes considered. Although such black holes are found only in the IR, we argue that black holes with universal horizons also exist in the full theory of the HL gravity. A simple example is the Schwarzschild solution written in the Painleve–Gullstrand coordinates, which is also a solution of the full theory of the HL gravity and has a universal horizon located inside the Schwarzschild Killing horizon.
Modified Einstein and Finsler like theories on tangent Lorentz bundles
Authors: Stavrinos Panayiotis , Vacaru Olivia , Vacaru Sergiu I.
Published: October 2014

In this paper, we study modifications of general relativity, GR, with nonlinear dispersion relations which can be geometrized on tangent Lorentz bundles. Such modified gravity theories, MGTs, can be modeled by gravitational Lagrange density functionals f(R, T, F) with generalized/modified scalar curvature R, trace of matter field tensors T and modified Finsler like generating function F. In particular, there are defined extensions of GR with extra dimensional "velocity/momentum" coordinates. For four-dimensional models, we prove that it is possible to decouple and integrate in very general forms the gravitational fields for f(R, T, F)-modified gravity using nonholonomic 2 + 2 splitting and nonholonomic Finsler like variables F. We study the modified motion and Newtonian limits of massive test particles on nonlinear geodesics approximated with effective extra forces orthogonal to the four-velocity. We compute the constraints on the magnitude of extra-accelerations and analyze perihelion effects and possible cosmological implications of such theories. We also derive the extended Raychaudhuri equation in the framework of a tangent Lorentz bundle. Finally, we speculate on effective modeling of modified theories by generic off-diagonal configurations in Einstein and/or MGTs and Finsler gravity. We provide some examples for modified stationary (black) ellipsoid configurations and locally anisotropic solitonic backgrounds.
A Numerical Investigation on Sound Absorption Mechanism of Micro Resonator with Offset Slits
Authors: Xu Jun , Li Xiaodong , Guo Yueping
Published: October 2014

Acoustic liners are widely used in commercial aero-engine to suppress noise. In theoretical investigations, the liner geometry is often assumed as an array of symmetric micro resonator with orifice or slit at the center. However, in real application, orifices or slits distributed in micro resonator are offset. For better understanding of sound absorption mechanism of micro resonator with offset slits under high incident sound pressure level (SPL), direct numerical simulations (DNS) using high order low dispersion and low dissipation computational aeroacoustics (CAA) method are carried out. The simulations are first validated by experimental data, showing good agreement and establishing the relevance of the simulation methodology. Numerical simulations of resonators with single offset slit or two slits are then conducted. The two sound absorption mechanisms, namely viscous dissipation and vortex shedding, are discussed with detailed numerical data and analysis, which lead to quantitative parametric description of the energy partition between the two mechanisms as a function of both frequency and geometry. It is shown that offset slit can reduce vortex shedding and results in less sound absorption. The effects of more than one slit are, however, opposite; more vortex shedding occurs with more slits so that sound absorption is enhanced. This may potentially help guide liner design in practical applications.
Universal optimal quantum correlator
Authors: Buscemi Francesco , Dall'Arno Michele , Ozawa Masanao , Vedral Vlatko
Published: October 2014

Recently, a novel operational strategy to access quantum correlation functions of the form Tr[AρB] was provided in [F. Buscemi, M. Dall'Arno, M. Ozawa and V. Vedral, arXiv:1312.4240]. Here we propose a realization scheme, that we call partial expectation values, implementing such strategy in terms of a unitary interaction with an ancillary system followed by the measurement of an observable on the ancilla. Our scheme is universal, being independent of ρ, A, and B, and it is optimal in a statistical sense. Our scheme is suitable for implementation with present quantum optical technology, and provides a new way to test uncertainty relations.
Line Intersection Algorithm for the Enhanced TOA Trilateration Technique
Authors: Pradhan Sajina , Hwang Suk-Seung , Cha Hyun-Rok , Bae Young-Chul
Published: October 2014

The location determination technology (LDT) is one of the core techniques for the location-based services (LBS) which has various applications, including a mobile robot, for the modern wireless communication system. The time of arrival (TOA), which is a kind of LDTs based on the cellular network, estimates the location of the specific user or object using a trilateration method based on the received signals from three base stations (BS). The true location of a mobile station (MS) is determined based on an intersection point of three circles with the radius corresponding to the distance between each BS to MS. Since the TOA method estimates the distance between BS and MS using the number of time delay, these three circles should not generally meet at a point and the performance of the location detection should be degraded in this case. In order to overcome this problem, we propose the mobile location detection algorithm based on a line intersection of the TOA geometry. In the case of those three circles do not meet at a point; in general, there are six intersection points and three lines which connect two intersection points. In this paper, we determine an intersection point of three lines as the location of a MS. The computer simulation example is provided to illustrate the location detection performance of the proposed algorithm.
THE IMPACT OF ACQUISITIONS ON NEW TECHNOLOGY STOCKS: THE GOOGLE–MOTOROLA CASE
Authors: GAO RENFEI , WANG CINDY S. H. , HAFNER CHRISTIAN M.
Published: October 2014

This paper analyzes the impact of the recent acquisition of Motorola by Google on the subsequent performance of stock returns using an event study methodology. We obtain empirical results by a two-stage regression, by which the impact of market and industry effects can be controlled for. Our findings suggest that the Motorola takeover led to negative and significant excess returns to Google, but positive and highly significant excess returns to Motorola. Additionally, while the event led to significantly positive excess returns to direct competitors, it did not have a strong impact on indirect competitors, suggesting that the importance of the event was restricted to related industries.
Eocene magmatism in the Tethyan Himalaya, southern Tibet
Authors: Zeng Lingsen , Gao Li-E , Tang Suohang , Hou Kejun , Guo Chunli , Hu Guyue
Published: October 2014

Recent studies in the Yardoi gneiss dome of the Tethyan Himalaya, southern Tibet demonstrated that the Himalayan orogenic belt experienced a major episode of crustal melting in the Mid-Eocene (
c.
44–40 Ma), represented by the genesis of a suite of high Sr/Y two-mica granites (TMGs) accompanied by leucogranites. Geochemical and U–Pb age data indicate that (1) both the leucogranite and the porphyritic leucogranite formed at
c.
44–41 Ma are characterized by similar Sr–Nd–Hf isotope systematics to those in the less evolved TMGs; (2) these three suites of rocks might represent a Mid-Eocene igneous complex derived from partial melting of amphibolite under crustal thickened conditions; and (3) in contrast with the TMGs, leucogranites experienced hydrothermal-magma interactions as well as plagioclase fractional crystallization as revealed from pronounced negative Eu anomalies, much lower Sr concentrations, and elevated common Pb and U concentrations in the latest magmatic zircon overgrowth. Our data suggest that magmatic differentiation of more primitive magmas could have played a critical role in the generation of leucogranites. Documentation of partial melting of deep crustal rocks during the earliest phase of the tectonic evolution of the Himalayan orogen implies that the large-scale collisional orogenic belt could experience intensive partial melting under contraction and thickening conditions, which could profoundly affect the geophysical and geochemical properties as well as rheological properties and facilitate the initiation of movement or flow of deep crustal rocks.
Near-Optimality in Covering Games by Exposing Global Information
Authors: Balcan Maria-Florina , Krehbiel Sara , Piliouras Georgios , Shin Jinwoo
Published: October 2014

Mechanism design for distributed systems is fundamentally concerned with aligning individual incentives with social welfare to avoid socially inefficient outcomes that can arise from agents acting autonomously. One simple and natural approach is to centrally broadcast nonbinding advice intended to guide the system to a socially near-optimal state while still harnessing the incentives of individual agents. The analytical challenge is proving fast convergence to near optimal states, and in this article we give the first results that carefully constructed advice vectors yield stronger guarantees.

We apply this approach to a broad family of potential games modeling vertex cover and set cover optimization problems in a distributed setting. This class of problems is interesting because finding exact solutions to their optimization problems is NP-hard yet highly inefficient equilibria exist, so a solution in which agents simply locally optimize is not satisfactory. We show that with an arbitrary advice vector, a set cover game quickly converges to an equilibrium with cost of the same order as the square of the social cost of the advice vector. More interestingly, we show how to efficiently construct an advice vector with a particular structure with cost
O
(log
n
) times the optimal social cost, and we prove that the system quickly converges to an equilibrium with social cost of this same order.
Altruism and Its Impact on the Price of Anarchy
Authors: Chen Po-An , Keijzer Bart De , Kempe David , Schäfer Guido
Published: October 2014

We study the inefficiency of equilibria for congestion games when players are (partially) altruistic. We model altruistic behavior by assuming that player
i
's perceived cost is a convex combination of α
i
times his direct cost and α
i
times the social cost. Tuning the parameters α
i
allows smooth interpolation between purely selfish and purely altruistic behavior. Within this framework, we study primarily altruistic extensions of (atomic and nonatomic) congestion games, but also obtain some results on fair cost-sharing games and valid utility games.

We derive (tight) bounds on the price of anarchy of these games for several solution concepts. Thereto, we suitably adapt the
smoothness
notion introduced by Roughgarden and show that it captures the essential properties to determine the
robust price of anarchy
of these games. Our bounds show that for atomic congestion games and cost-sharing games, the robust price of anarchy gets worse with increasing altruism, while for valid utility games, it remains constant and is not affected by altruism.

However, the increase in the price of anarchy is not a universal phenomenon: For general nonatomic congestion games with uniform altruism, the price of anarchy improves with increasing altruism. For atomic and nonatomic symmetric singleton congestion games, we derive bounds on the pure price of anarchy that improve as the
average
level of altruism increases. (For atomic games, we only derive such bounds when cost functions are linear.) Since the bounds are also strictly lower than the robust price of anarchy, these games exhibit natural examples in which pure Nash equilibria are more efficient than more permissive notions of equilibrium.
Utilizing Structural Equation Modeling and Social Cognitive Career Theory to Identify Factors in Choice of IT as a Major
Authors: Luse Andy , Rursch Julie A. , Jacobson Doug
Published: October 2014

In the United States, the number of students entering into and completing degrees in science, technology, engineering, and mathematics (STEM) areas has declined significantly over the past decade. Although modest increases have been shown in enrollments in computer-related majors in the past 4 years, the prediction is that even in 3 to 4 years when these students graduate, there will be shortages of computer-related professionals for industry. The challenge on which this article focuses is attracting students to select an information technology (IT) field such as computer science, computer engineering, software engineering, or information systems as a major when many high schools do not offer a single computer course, and high school counselors, families, and friends do not provide students with accurate information about the field. The social cognitive career theory (SCCT) has been used extensively within counseling and career psychology as a method for understanding how individuals develop vocational interests, make occupational choices, and achieve success within their chosen field. In this article, the SCCT model identifies factors that specifically influence high school students to select a major in an IT-related discipline. These factors can then be used to develop new or enhance existing IT-related activities for high school students. Our work demonstrates that both interest and outcome expectations have a significant positive impact on choice to major. Interest also is found to mediate the effects of self-efficacy and outcome expectations on choice of major. Overall, the model predicts a good portion of variance in the ultimate outcome of whether or not an individual chooses to major in IT.
NUCA-L1
Authors: Hijaz Farrukh , Khan Omer
Published: October 2014

Research has shown that operating in the near-threshold region is expected to provide up to 10× energy efficiency for future processors. However, reliable operation below a minimum voltage (Vccmin) cannot be guaranteed due to process variations. Because SRAM margins can easily be violated at near-threshold voltages, their bit-cell failure rates are expected to rise steeply. Multicore processors rely on fast private L1 caches to exploit data locality and achieve high performance. In the presence of high bit-cell fault rates, traditionally an L1 cache either sacrifices capacity or incurs additional latency to correct the faults. We observe that L1 cache sensitivity to hit latency offers a design trade-off between capacity and latency. When fault rate is high at extreme Vccmin, it is beneficial to recover L1 cache capacity, even if it comes at the cost of additional latency. However, at low fault rates, the additional constant latency to recover cache capacity degrades performance. With this trade-off in mind, we propose a Non-Uniform Cache Access L1 architecture (NUCA-L1) that avoids additional latency on accesses to fault-free cache lines. To mitigate the capacity bottleneck, it deploys a correction mechanism to recover capacity at the cost of additional latency. Using extensive simulations of a 64-core multicore, we demonstrate that at various bit-cell fault rates, our proposed private NUCA-L1 cache architecture performs better than state-of-the-art schemes, along with a significant reduction in energy consumption.
Economic Model-Driven Cloud Service Composition
Authors: Ye Zhen , Bouguettaya Athman , Zhou Xiaofang
Published: October 2014

This article considers cloud service composition from a decision analysis perspective. Traditional QoS-aware composition techniques usually consider the qualities available at the time of the composition because compositions are usually immediately consumed. This is fundamentally different in the cloud environment where the cloud service composition typically lasts for a relatively long period of time. The two most important drivers when composing cloud service are the long-term nature of the composition and the economic motivation for outsourcing tasks to the cloud. We propose an economic model, which we represent as a Bayesian network, to select and compose cloud services. We then leverage influence diagrams to model the cloud service composition. We further extend the traditional influence diagram problem to a hybrid one and adopt an extended Shenoy-Shafer architecture to solve such hybrid influence diagrams that include deterministic chance nodes. In addition, analytical and simulation results are presented to show the performance of the proposed composition approach.
EFGR
Authors: Tavva Venkata Kalyan , Kasha Ravi , Mutyam Madhu
Published: October 2014

High-density DRAM devices spend significant time refreshing the DRAM cells, leading to performance drop. The JEDEC DDR4 standard provides a Fine Granularity Refresh (FGR) feature to tackle refresh. Motivated by the observation that in FGR mode, only a few banks are involved, we propose an Enhanced FGR (EFGR) feature that introduces three optimizations to the basic FGR feature and exposes the bank-level parallelism within the rank even during the refresh. The first optimization decouples the nonrefreshing banks. The second and third optimizations determine the maximum number of nonrefreshing banks that can be active during refresh and selectively precharge the banks before refresh, respectively. Our simulation results show that the EFGR feature is able to recover almost 56.6% of the performance loss incurred due to refresh operations.
Economic Viability of Paris Metro Pricing for Digital Services
Authors: Chau Chi-Kin , Wang Qian , Chiu Dah-Ming
Published: October 2014

Nowadays digital services, such as cloud computing and network access services, allow dynamic resource allocation and virtual resource isolation. This trend can create a new paradigm of flexible pricing schemes. A simple pricing scheme is to allocate multiple isolated service classes with differentiated prices, namely Paris Metro Pricing (PMP). The benefits of PMP are its simplicity and applicability to a wide variety of general digital services, without considering specific performance guarantees for different service classes. The central issue of our study is whether PMP is economically viable, namely whether it will produce more profit for the service provider and whether it will achieve more social welfare. Prior studies had only considered specific models and arrived at conflicting conclusions. In this article, we identify unifying principles in a general setting and derive general sufficient conditions that can guarantee the viability of PMP. We further apply the results to analyze various examples of digital services.
Revenue Guarantees in the Generalized Second Price Auction
Authors: Caragiannis Ioannis , Kaklamanis Christos , Kanellopoulos Panagiotis , Kyropoulou Maria
Published: October 2014

Sponsored search auctions are the main source of revenue for search engines. In such an auction, a set of utility maximizing advertisers competes for a set of ad slots. The assignment of advertisers to slots depends on the bids they submit; these bids may be different than the true valuations of the advertisers for the slots. Variants of the celebrated VCG auction mechanism guarantee that advertisers act truthfully and, under some assumptions, lead to revenue or social welfare maximization. Still, the sponsored search industry mostly uses generalized second price (GSP) auctions; these auctions are known to be nontruthful and suboptimal in terms of social welfare and revenue. In an attempt to explain this tradition, we study a Bayesian setting wherein the valuations of advertisers are drawn independently from a common regular probability distribution. In this setting, it is well known from the work of Myerson [1981] that the optimal revenue is obtained by the VCG mechanism with a particular reserve price that depends on the probability distribution. We show that, by appropriately setting the reserve price, the revenue over any Bayes-Nash equilibrium of the game induced by the GSP auction is at most a small constant factor away from the optimal revenue, improving previous results of Lucier et al. [2012]. Our analysis is based on the Bayes-Nash equilibrium conditions and the improved results are obtained by bounding the utility of each player at equilibrium using infinitely many deviating bids and also by developing novel prophet-like inequalities.
Is the Price of Anarchy the Right Measure for Load-Balancing Games?
Authors: Doncel Josu , Ayesta Urtzi , Brun Olivier , Prabhu Balakrishna
Published: October 2014

Price of anarchy is an oft-used worst-case measure of the inefficiency of noncooperative decentralized architectures. For a noncooperative load-balancing game with two classes of servers and for a finite or infinite number of dispatchers, we show that the price of anarchy is an overly pessimistic measure that does not reflect the performance obtained in most instances of the problem. We explicitly characterize the worst-case traffic conditions for the efficiency of noncooperative load-balancing schemes and show that, contrary to a common belief, the worst inefficiency is in general not achieved in heavy traffic.
Secure Team Composition to Thwart Insider Threats and Cyber-Espionage
Authors: Laszka Aron , Johnson Benjamin , Schöttle Pascal , Grossklags Jens , Böhme Rainer
Published: October 2014

We develop a formal nondeterministic game model for secure team composition to counter cyber-espionage and to protect organizational secrets against an attacker who tries to sidestep technical security mechanisms by offering a bribe to a project team member. The game captures the adversarial interaction between the attacker and the project manager who has a secret she wants to protect but must share with a team of individuals selected from within her organization. Our interdisciplinary work is important in the face of the multipronged approaches utilized by well-motivated attackers to circumvent the fortifications of otherwise well-defended targets.
Recommendation and Weaving of Reusable Mashup Model Patterns for Assisted Development
Authors: Roy Chowdhury Soudip , Daniel Florian , Casati Fabio
Published: October 2014

With this article, we give an answer to one of the open problems of mashup development that users may face when operating a model-driven mashup tool, namely the
lack of modeling expertise
. Although commonly considered simple applications, mashups can also be complex software artifacts depending on the number and types of Web resources (the components) they integrate. Mashup tools have undoubtedly simplified mashup development, yet the problem is still generally nontrivial and requires intimate knowledge of the components provided by the mashup tool, its underlying mashup paradigm, and of how to apply such to the integration of the components. This knowledge is generally neither intuitive nor standardized across different mashup tools and the consequent lack of modeling expertise affects both skilled programmers and end-user programmers alike.

In this article, we show how to effectively assist the users of mashup tools with contextual, interactive recommendations of composition knowledge in the form of reusable mashup model patterns. We design and study three different recommendation algorithms and describe a pattern weaving approach for the one-click reuse of composition knowledge. We report on the implementation of three pattern recommender plugins for different mashup tools and demonstrate via user studies that recommending and weaving contextual mashup model patterns significantly reduces development times in all three cases.
On the Power of Deterministic Mechanisms for Facility Location Games
Authors: Fotakis Dimitris , Tzamos Christos
Published: October 2014

We consider
K
-Facility Location games, where
n
strategic agents report their locations in a metric space and a mechanism maps them to
K
facilities. The agents seek to minimize their connection cost, namely the distance of their true location to the nearest facility, and may misreport their location. We are interested in deterministic mechanisms that are strategyproof, that is, ensure that no agent can benefit from misreporting her location, do not resort to monetary transfers, and achieve a bounded approximation ratio to the total connection cost of the agents (or to the
L

p

norm of the connection costs, for some
p
∈ [1, ∞) or for
p
= ∞).

Our main result is an elegant characterization of deterministic strategyproof mechanisms with a bounded approximation ratio for 2-Facility Location on the line. In particular, we show that for instances with
n
≥ 5 agents, any such mechanism either admits a unique dictator or always places the facilities at the leftmost and the rightmost location of the instance. As a corollary, we obtain that the best approximation ratio achievable by deterministic strategyproof mechanisms for the problem of locating 2 facilities on the line to minimize the total connection cost is precisely
n
-2. Another rather surprising consequence is that the Two-Extremes mechanism of Procaccia and Tennenholtz [2009] is the only deterministic anonymous strategyproof mechanism with a bounded approximation ratio for 2-Facility Location on the line.

The proof of the characterization employs several new ideas and technical tools, which provide new insights into the behavior of deterministic strategyproof mechanisms for
K
-Facility Location games and may be of independent interest. Employing one of these tools, we show that for every
K
≥ 3, there do not exist any deterministic anonymous strategyproof mechanisms with a bounded approximation ratio for
K
-Facility Location on the line, even for simple instances with
K
+1 agents. Moreover, building on the characterization for the line, we show that there do not exist any deterministic strategyproof mechanisms with a bounded approximation ratio for 2-Facility Location and instances with
n
≥ 3 agents located in a star.
Implementation and Computation of a Value for Generalized Characteristic Function Games
Authors: Michalak Tomasz P. , Szczepański Piotr L. , Rahwan Talal , Chrobak Agata , Brânzei Simina , Wooldridge Michael , Jennings Nicholas R.
Published: October 2014

Generalized characteristic function games
are a variation of characteristic function games, in which the value of a coalition depends not only on the identities of its members, but also on the order in which the coalition is formed. This class of games is a useful abstraction for a number of realistic settings and economic situations, such as modeling relationships in social networks. To date, two main extensions of the Shapley value have been proposed for generalized characteristic function games: the Nowak-Radzik [1994] value and the Sánchez-Bergantiños [1997] value. In this context, the present article studies generalized characteristic function games from the point of view of implementation and computation. Specifically, the article makes two key contributions. First, building upon the mechanism by Dasgupta and Chiu [1998], we present a non-cooperative mechanism that implements both the Nowak-Radzik value and the Sánchez-Bergantiños value in Subgame-Perfect Nash Equilibria in expectations. Second, in order to facilitate an efficient computation supporting the implementation mechanism, we propose the Generalized Marginal-Contribution Nets representation for this type of game. This representation extends the results of Ieong and Shoham [2005] and Elkind et al. [2009] for characteristic function games and retains their attractive computational properties.
Resolution of the Age-Old Dilemma about a Magnitude of the Momentum of Light in Matter
Authors: Torchigin V. P. , Torchigin A. V.
Published: October 2014

There are two competitive opinions about a magnitude of the momentum of light in matter. The Balazs thought experiment gives unambiguous theoretical evidence based only on laws of mechanics that the momentum of light in matter is smaller by n times than that of the same light in free space where n is the refractive index of the matter. On the other hand, there is other theoretical evidence confirmed by experimental investigation that the momentum of light in matter is greater by n times than that in free space. This ancient dilemma cannot be resolved till now. We show that the momentum density flux of light in matter is greater by n times than that in free space. In the same time we present an alternative interpretation of the Balazs thought experiment where two optical pressures arising in the regions of the matter where leading and trailing edges of the pulse are propagating are taken into account. This enables us to match contradictory results of mentioned experiments. Since the contradiction is overcome, the dilemma disappears.
Effect of Rat Medicated Serum Containing You Gui Wan on Mouse Oocyte In Vitro Maturation and Subsequent Fertilization Competence
Authors: Jiang Xiao-Hui , Deng Yan-li , Lu Hua , Duan Heng , Zhen Xia , Hu Xiang , Liang Xin , Yie Shang-mian
Published: October 2014

You Gui Wan (YGW) is a classic herbal formula in traditional Chinese medicine (TCM) used for the clinical treatment of infertility. This study was to explore whether YGW has an impact on mouse oocyte maturation in vitro and subsequent fertilization competence. Rat medicated serum containing YGW was prepared by orally administrating YGW. Mouse immature oocytes were cultured with YGW medicated serum and compared to those cultured with or without normal rat serum or follicle‐stimulating hormone (FSH). YGW medicated serum significantly increased the percentages of matured oocytes when compared to the groups with or without normal rat serum (P < 0.01). Furthermore, YGW medicated serum increased the rate of in vitro fertilization (IVF) when compared to the groups treated with FSH and with or without normal rat serum (P < 0.001). YGW medicated serum also had significant effects on the mRNA expressions of PKA, CREB, MAPK, PKC, PKG, and MPF and the concentrations of cAMP, cGMP, and NO in matured oocytes. These results indicate that YGW can promote mouse oocyte maturation and IVF in vitro. Signaling pathways, such as the cAMP/PKA/MAPK, the PKC‐MAPK, and the NO‐cGMP‐PKG pathway, which are similar to those induced by FSH, may be responsible for this action.
Testing for Partial RhD with a D-Screen Diagast Kit in Moroccan Blood Donors with Weak D Expression
Authors: Kabiri Z. , Benajiba M. , Hajjout K. , Dakka N. , Bellaoui H.
Published: October 2014

The aim of this study was to search for the partial D phenotype in Moroccan blood donors with weak D expression. The study included 32 samples with weak D phenotype, and partial D category red blood cells were detected with the D-Screen Diagast kit, which consists in 9 monoclonal anti-D antibodies specific for the most common categories of partial D. Among the 32 samples studied, we identified 13 specific reactions to a partial D antigen (3 DVI, 2 DVa, 2 DIII(a,b,c), and 6 DVII), with 8 reactions suggesting a weak D and 11 reactions providing no formal argument in favor of a partial D antigen. This work can be used to validate the performance of the anti-D reagent and to improve the safety of transfusion of red blood cells from donors expressing the partial D antigen by integrating the finding into the recipient file with a recommendation concerning the appropriate care.
Incremental Hemodialysis Schedule in Patients with Higher Residual Renal Function at the Start of Dialysis
Authors: Lucas Milagros Fernández , Teruel José Luis , Ruíz-Roso Gloria , Díaz Martha , Raoch Viviana , Caravaca Fernando , Quereda Carlos
Published: October 2014

We present an observational study to evaluate a progressive schedule of dose of dialysis, starting with 2 HD/week, when the renal clearance of urea was equal to or greater than 2,5 mL/min/1,73 m2and the patient is in a stable clinical situation. From 2006 to 2011, 182 patients started hemodialysis in our center, of which 134 were included in the study. Residual renal function (RRF), Kt/V, eKru, nPCR, hemoglobin, weekly erythropoietin dose, and beta-2-microglobulin were determined at 6, 12, 18, 24, and 30 months after dialysis initiation. Seventy patients (52%) began with the progressive schedule of 2 HD/week and 64 (48%) patients began with the conventional thrice-weekly schedule (3 HD/week). The decline of RRF was lower in the group of 2 HD/week: 0,20 (0,02–0,53) versus 0,50 (0,14–1,08) mL/min/month (median and interquartile range,P=0,009). No relationship was found between the decline rate and the basal RRF. Survival analysis did not show differences between both groups. Our experience demonstrates that patients with higher residual renal function may require less than conventional 3 HD sessions per week at the start of dialysis. Twice-weekly hemodialysis schedule is safe and cost-effective and may have additional benefit in maintaining the residual renal function.
Flow of a Burger’s Fluid in a Channel Induced by Peristaltic Compliant Walls
Authors: Ahmad I. , Ali N. , Abbasi A. , Aziz W. , Hussain M. , Ahmad M. , Taj M. , Zaman Q.
Published: October 2014

A theoretical analysis is presented for the peristaltic motion of a magneto-hydrodynamic (MHD) non-Newtonian fluid in channel with complaint walls. The fluid obeys viscoelastic non-Newtonian model with Burger’s constitutive equation. The relevant equations are first developed and then solved using perturbation technique. Expressions of stream function and velocity components are constructed under the assumption thatδ(characteristic ratio of transversal and axial scales of peristaltic motion) is small. The results indicate the strong effects of Burger’s fluid parameter, Hartman number, Reynolds number, and complaint wall parameters on the velocity field and stream function. The obtained solutions are shown graphically for the different values of involved parameters.