bluuebunny/crossref_metadata_2025 huggingface dataset:
Ontogenetic variation in Silurian eurypterids from Ontario and New York State
Authors: Cuggy Michael B.
Published: April 2010

For more than 150 years, eurypterids from the Upper Silurian Bertie Formation of New York State and southern Ontario have been assigned to two species: Eurypterus remipes DeKay, 1825 and Eurypterus lacustris Harlan, 1834. These species have been distinguished on overall size and on the length–width ratios of the prosomas. To test the hypothesis that these taxa are simply ontogenetic variants of a single species, a biometrical study of more than 140 specimens from eight localities was performed. Bivariate plots of prosomal length versus width showed that E. remipes and E. lacustris morphs form a single ontogenetic growth series. Multivariate analysis using principal component analysis on nine measurement variables demonstrated that there is no basis for distinguishing between the two species on prosomal morphology. Accordingly E. lacustris is synonymized with E. remipes.
The seismic velocity and Poisson's ratio structure of the Kapuskasing uplift from laboratory measurements
Authors: Salisbury Matthew H. , Fountain David M.
Published: April 2010

The compressional (Vp) and shear (Vs) wave velocity structure of the Kapuskasing uplift have been determined as a function of depth, propagation direction, and polarization from laboratory velocity measurements to confining pressures of 600 MPa on oriented samples from known structural levels of the complex. Based on the relative field abundances of the lithologies measured, the three principal terranes exposed in the uplift are characterized at depth by the following average values of Vp, Vs, and apparent Poisson's ratio, σa: (i) Michipicoten greenstone bell (greenschist, depth 0–6 km, Vp = 6.6 km/s, Vs = 3.9 km/s, σa = 0.235); (ii) Wawa gneiss terrane (amphibolite, depth 6–17 km, Vp = 6.5 km/s, Vs = 3.8 km/s, σa = 0.24); and (iii) Kapuskasing structural zone (granulite, depth 17–23 km, Vp = 6.9 km/s, Vs = 3.9 km/s, σa = 0.27). Although anisotropic lithologies such as paragneiss or mafic gneiss are present at all levels and tend to increase in abundance with depth, only in the deepest level (the Kapuskasing zone) are they sufficiently abundant and oriented to produce significant regional seismic anisotropy (transversely isotropic with Vp and Vs fast in the horizontal plane) and detectable shear wave splitting (ΔVs = 0.1 km/s).A comparison between the laboratory data and velocity models determined for the same crustal section from Lithoprobe refraction studies shows excellent agreement, confirming that the lithologies exposed in the Kapuskasing uplift can be projected downdip to the upper–lower crust transition, or Conrad discontinuity, at about 25 km. Below this depth, high P-wave velocities (7.0–7.6 km/s) suggest that the lower crust is more mafic or garnet rich. Similarities between the velocity structure of the Kapuskasing uplift and other sites in the Canadian Shield suggest that the observed crustal section is fairly typical of Archean continental crust.
Constraints on the nature of the Kapuskasing structural zone from the study of Proterozoic dyke swarms
Authors: Halls H. C. , Palmer H. C. , Bates M. P. , Phinney Wm. C.
Published: April 2010

Petrochemical, paleomagnetic, and structural studies on Early Proterozoic dyke swarms show that the rocks of the Kapuskasing structural zone (KSZ), central Superior Province, were upthrust about 10–15 km along the Ivanhoe Lake fault after intrusion of 2.04 Ga Kapuskasing dykes. This uplift was part of a more widespread deformation in flanking terranes that involved sinistral motion along north–north-northwest-trending faults, dextral displacement along east-northeast–northeast-trending faults, and a distortion of the 2.45 Ga Matachewan swarm to the west and northwest of the Ivanhoe Lake fault. The most spectacular demonstration that the KSZ is largely a product of Proterozoic deformation is that Matachewan dykes change their magnetic polarity on crossing the zone, a consequence of remanence acquisition at deep crustal levels being delayed until after a reversal of the earth's magnetic field and prior to uplift of the dykes.Matachewan and Kapuskasing dykes within the amphibolite- to granulite-grade rocks of the KSZ are relatively fresh and contain a high-alumina green amphibole and feldspar laths that exhibit tea-coloured clouding due to the presence of submicroscopic inclusions of magnetite. These features may be diagnostic of crystallization at deeper crustal levels because they are found in regions where Rb–Sr biotite ages from tonalites suggest broad-scale uplift of the crust after about 2 Ga. About 50 km west of the KSZ, dykes exhibiting clouded feldspar and high-alumina amphiboles occur on the upthrown side of the Budd Lake fault zone, which has a trend similar to that of the Ivanhoe Lake fault. Therefore a second thrust block may exist, raising the possibility that the KSZ represents the basal member of a series of imbricate thrust slices that extends westwards from the Ivanhoe Lake fault. Radiometric age data suggest that the region affected by this Early Proterozoic deformation continues to the northwest for a further 300 km.
Review: Receiver function studies in the southern Canadian Cordillera
Authors: Cassidy John F.
Published: April 2010

Receiver function analysis has proven to be a powerful, yet inexpensive tool for estimating the S-wave velocity structure of the crust and upper mantle beneath three-component seismograph stations in the southern Canadian Cordillera. Receiver function studies using a portable broadband seismograph array across southwestern British Columbia provided site-specific estimates for the location of the subducting Juan de Fuca plate. The oceanic crust was imaged at 47−53 km beneath central Vancouver Island, and 60–65 km beneath the Strait of Georgia. Further, these studies revealed a prominent low-velocity zone (VS = −1.0 km/s) that coincides with the E reflectors imaged ~5–10 km above the subducting plate on Lithoprobe reflection lines. The E low-velocity zone was shown to extend into the upper mantle beneath the Strait of Georgia and the British Columbia mainland, to depths of 50–60 km. Combining the receiver function and refraction models revealed a high Poisson's ratio (0.27–0.38) for this feature. The continental Moho was estimated at 36 km beneath the Strait of Georgia, and a crustal low-velocity zone associated with the Lithoprobe C reflectors beneath Vancouver Island was interpreted to extend eastward, near the base of the continental crust, to the British Columbia mainland. Analysis of data from the recently deployed Canadian National Seismograph Network demonstrates the variations in crustal thickness and complexity across the southern Canadian Cordillera, with the Moho depth varying from 35 km in the Coast Mountains, to 33 km near Penticton, to 50 km near the Rocky Mountain deformation front.
Review: The thermal regime along the southern Canadian Cordillera Lithoprobe corridor
Authors: Hyndman R. D. , Lewis T. J.
Published: April 2010

This summary article describes the surface heat flow and heat generation data available for the Southern Canadian Cordillera Lithoprobe Transect, and the inferred crustal temperatures. At the western end of the transect, the continental margin has the characteristic heat flow pattern of a subduction zone; there are high heat flows over the young oceanic crust of the deep-sea Cascadia Basin (~120 mW·m−2), decreasing values landward on the continental slope and shelf (90–50 mW·m−2), and very low heat flow and low crustal temperatures in the forearc region of Vancouver Island and the adjacent mainland (30–40 mW·m−2). Very high and irregular heat flow occurs in the Garibaldi Volcanic Belt at the northern end of the Cascade volcanic arc. To the east, across the Intermontane and Omineca belts to the Rocky Mountain Trench, the heat flow and inferred crustal temperatures are high. The highest values are in the east in the Omineca Belt, where the radioactive heat generation is especially great. The crustal thermal regime has important implications for the interpretation of the deep seismic structure: (1) The brittle–ductile transition (~450 °C), which occurs in the mid-crust for most of the transect, is expected to represent a general level of thrust and normal fault detachment. The deeper crust may be mechanically decoupled from that above. (2) Crustal thickness may be related to temperature. If the lithosphere temperature is high and its density decreased by thermal expansion, there can be isostatic equilibrium with a thin crust and high topography. (3) The thermal regime appears to control the depth to the widespread crustal reflectivity and high electrical conductivity in the deep crust.
Magmatic origins of calc-alkaline intrusions from the Coast Plutonic Complex, southwestern British Columbia
Authors: Cui Yao , Russell J. K.
Published: April 2010

Major element, trace element, and rare earth element data are presented for Permian to Tertiary calc-alkaline plutonic and volcanic rocks along a transect across the southern Coast Plutonic Complex from Vancouver to Anderson Lake. Late Jurassic to Late Cretaceous plutons are divided into two compositional suites based on mineralogy: (1) the hornblende intrusive suite (tonalite, quartz diorite, diorite, and gabbro) characterized by abundant modal hornblende and little or no K-feldspar, and (2) the K-feldspar intrusive suite (mainly granite and granodiorite) containing significant modal K-feldspar and less hornblende. Compositions of hornblende intrusive suite rocks are effectively portrayed on Pearce element-ratio diagrams utilizing axes X1 = [0.8571 Si−0.1429(Fe + Mg) + 1.2857 Ca + 1.8574 K]/Zr and Y1 = 1.1428 Ti + Al + Fe + Mg + Ca + 1.5714 Na + 0.4762 P]/Zr, because the diagram accounts for the stoichiometry of PI ± Hbl ± Bt ± Ep ± Ttn + Ap. Rocks from the K-feldspar intrusive suite are studied on diagrams using the element-ratio pair X2 = [2 Ti + Al + 3.3333 P]/Zr and Y2 = [2 Ca + Na + K]/Zr, which creates a linear trend of compositional variations controlled by the phases PI ± Kfs ± Bt ± Ttn + Ap. Mean intercepts of model trends on the element-ratio diagrams suggest differences among plutons that relate to source-region processes. For example, samples belonging to the hornblende intrusive suite represent a minimum of six batches of magma. Mean intercept values for plutons west of the Owl Lake–Harrison fault zone are significantly higher than those situated east of this structural break. These systematic differences allude to fundamental differences in the nature of Mesozoic magmatism in Wrangellia (and Harrison) terrane compared with that in Cadwallader, Bridge River, and Methow terranes, and probably in the Intermontane superterrane east of the structural break.
U–Pb geochronology of Jurassic to early Tertiary granitic intrusives from the Nelson–Castlegar area, southeastern British Columbia, Canada
Authors: Ghosh Dipak K.
Published: April 2010

Eleven U–Pb zircon dates from seven intrusives in the Nelson–Castlegar area provide new age constraints on the granitoid magmatism in southeastern British Columbia. Four samples from the Nelson Batholith date three distinct intrusive phases spanning ca. 10 Ma. One sample from the eastern porphyritic phase (Coffee Creek) yields the oldest age at 172.5 ± 5.0 Ma. Two samples from the central K-feldspar megacrystic phase (Crescent Bay) give precise ages at 162.0 ± 1.0 and 161.5 ± 1.5 Ma, and possibly date the youngest phase of the batholith. An intermediate age of emplacement at 166.0 ± 3.0 Ma is suggested for the southern tail of the batholith. The new and published data suggest that the Nelson Batholith was emplaced in roughly concentric zones. In contrast, the southern quartz diorite phase and the northwestern granodiorite phase of the Bonnington Pluton were emplaced coevally during the Middle Jurassic at 167.4 ± 2.0 and 165.0 ± 3.0 Ma, respectively. Middle Jurassic ages were also obtained for a sample of hornblende orthogneiss (166.0 ± 7.5 Ma) that intrudes the Trail Gneiss, and for a leucocratic gneiss sample (156.6 ± 6.0 Ma), a remnant from the Kinnaird Gneiss. A biotite granite sheet that intrudes the Kinnaird Gneiss yields a Middle Eocene age (40.5 ± 6.0 Ma), and possibly dates the youngest deformation event in the region. The Early Eocene ages (55.1 ± 3.7 and 50.6 ± 0.5 Ma) obtained from the Ladybird Granite and Coryell Syenite agree with previous estimates. Early Proterozoic ages of inherited zircon components in most of the samples agree with Nd–Sr isotopic evidence for incorporation of old crustal material in the intrusives empiaced in continental-arc settings.
Absorption detection using optical waveguide cavities
Authors: Loock Hans-Peter , Barnes Jack A. , Gagliardi Gianluca , Li Runkai , Oleschuk Richard D. , Wächter Helen
Published: April 2010

Cavity ring-down spectroscopy is a spectroscopic method that uses a high quality optical cavity to amplify the optical loss due to the light absorption by a sample. In this presentation we highlight two applications of phase-shift cavity ring-down spectroscopy that are suited for absorption measurements in the condensed phase and make use of waveguide cavities. In the first application, a fiber loop is used as an optical cavity and the sample is introduced in a gap in the loop to allow absorption measurements of nanoliters of solution at the micromolar level. A second application involves silica microspheres as high finesse cavities. Information on the refractive index and absorption of a thin film of ethylene diamine on the surface of the microresonator is obtained simultaneously by the measurements of the wavelength shift of the cavity mode spectrum and the change in optical decay time, respectively.
ATRP grafting of oligo(ethylene glycol) methacrylates from gold surface — Effect of monomer size on grafted chain and EO unit densities
Authors: Jin Zhilin , Brash John L. , Zhu Shiping
Published: April 2010

Oligo(ethylene glycol) methacrylate (OEGMA) was grafted from Au surface via surface-initiated atom-transfer radical polymerization (s-ATRP). The initiator density was adjusted by the mole fractions of surface-attachable ATRP initiator and diluting agent. Three OEGMA monomers of Mr 300, 475, and 1100 were used. The Au surfaces before and after modification were characterized by water contact angle and ellipsometry. The effect of monomer Mr and initiator density on surface chain density and EO unit density was investigated. It was found that at low initiator density (mole fraction of initiator of 2%–5%), poly(OEGMA) grafts had comparable surface chain density independent of OEGMA Mr. However, at high initiator density (mole fraction of initiator >10%), poly(OEGMA)1100 had obviously lower chain densities than poly(OEGMA)300 and poly(OEGMA)475, which could be attributed to the size difference of the monomers. The short chain length and low surface chain density of poly(OEGMA)1100 resulted in its relatively low surface EO unit density.
Imino Diels–Alder reaction — An efficient synthetic protocol for 2-methyl-4-substituted tetrahydroquinolines catalyzed by copper dipyridine dichloride
Authors: Kavitha C. S. , Hosamani K. M. , Harisha R. S.
Published: April 2010

For the first time, copper dipyridine dichloride (CuPy2Cl2) is used as an efficient and reusable catalyst for the imino Diels–Alder reaction of para-substituted anilines with N-vinylpyrrolidinone, N-vinylcarbazole, and N-vinylcaprolactam in acetonitrile to afford the corresponding 2-methyl-4-substituted-1,2,3,4-tetrahydroquinoline derivatives in excellent yields with good purity. The products were characterized by FTIR,1H NMR,13C NMR, MS, and elemental analysis.
Competition between electrochemical advanced oxidation and electrochemical hypochlorination of acetaminophen at boron-doped diamond and ruthenium dioxide based anodes
Authors: Boudreau Jordache , Bejan Dorin , Bunce Nigel J.
Published: April 2010

This work was undertaken to distinguish four pathways for the electrochemical oxidation of acetaminophen as a model organic substrate: (i) direct electron transfer from the substrate to the anode, (ii) reaction of the substrate with HO• at boron-doped diamond anodes, (iii) non-radical (two-electron) oxidation of the substrate at Ti/RuO2 anodes, and (iv) electrochemical hypochlorination if Cl– is present. Pathway (i) was isolated as a slow reaction when boron-doped diamond (BDD) was used as the anode in the range of water stability, whereas in the corresponding reaction with Ti/RuO2 only pathway (iii) could be detected. Pathway (ii) predominated for BDD in the potential range of water oxidation, and was the only mechanism leading to mineralization of the substrate. Comparison between chemical hypochlorination and electrochemical oxidation at Ti/RuO2 in the presence of chloride ion indicated that the latter process principally involves mediated hypochlorination. Oxidation at boron-doped diamond anodes in the presence of chloride was the most complex mechanistically, with competition between hypochlorination and the electrochemical “advanced oxidation process”; this led to the formation of chlorinated byproducts. The observation of mineralization under these conditions demonstrated cross-over between reaction pathways (ii) and (iv), even though hypochlorination appeared to be the initial pathway for loss of acetaminophen. The presence of chloride ion did not significantly retard mineralization of acetaminophen in the initial stages of oxidation, but significantly increased the energy requirement for complete mineralization. The results are discussed in the context of the use of electrochemical oxidation in waste management.
On the efficiency of phenol and cyclohexanone electrocatalytic hydrogenation — Effect of conditioning and working pH in acetic acid solution on palladium/fluorine-doped tin dioxide supported catalyst
Authors: Tountian Dihourahouni , Brisach-Wittmeyer Anne , Nkeng Paul , Poillerat Gérard , Ménard Hugues
Published: April 2010

The electrocatalytic hydrogenation (ECH) of phenol and cyclohexanone was performed on a conductive Pd/SnO2:F catalyst. The catalyst was obtained by the impregnation method. We studied the influence of the pH of the supporting electrolyte, the conditioning pH, and the quantity of the conditioning charge passed before hydrogenation. Fourier transform infrared spectroscopy analysis showed that the functionalization of the catalyst surface by the acetic acid electrolyte depends on the pH. A direct correlation was observed between the efficiency of the hydrogenation, the pH of the electrolyte, and the electrode conditioning charge. Phenol hydrogenation was favored in acidic media, whereas cyclohexanone hydrogenation needed an acidic medium for conditioning and a basic medium for hydrogenation. The ECH rate appeared to depend on the functionalization of the catalyst surface, the adsorption of the target organic molecule on the catalyst, and its structural modification with the pH.
GENERATING BLACK STRINGS IN HIGHER DIMENSIONS
Authors: LÓPEZ L. A. , FEINSTEIN A. , BRETÓN N.
Published: April 2010

Starting with a Zipoy–Voorhees line element, we construct and study the three-parameter family of solutions describing a deformed black string with arbitrary tension.
TRIAXIAL SHAPE IN Os–Pt REGION FROM GROUND STATES TO COLLECTIVE ROTATIONAL STATES
Authors: SHEN SHUIFA , WANG XIUJIE , WEN TINGDUN , PAN FENG , GU JIANZHONG , ZHU LIHUA , WU XIAOGUANG , DRAAYER J. P. , ZHENG SHIJIE , LIU HONGLIANG , CHEN YONGBO , WANG TINGTAI
Published: April 2010

In order to study the deformation of the nuclei which belongs to the transitional region between strongly deformed and spherical nuclei, the calculations of the total Routhian surfaces by means of the pairing-deformation-frequency self-consistent cranked shell model were carried out in order to investigate shape evolution in even-mass Os and Pt isotopes (176–202 Os and 182–204 Pt ) starting from the static nuclear ground states. It is found that some nuclear ground states such as in 196 Os and 188–194 Pt are neither oblate nor prolate. Instead, the ground-state minima in these nuclei are axially asymmetric in shape. In addition, a complementary approach is used to extract equilibrium γ0 value (nonaxially symmetric equilibrium shape parameter), which support our predictions.
HOPF BIFURCATION FROM LINES OF EQUILIBRIA WITHOUT PARAMETERS IN MEMRISTOR OSCILLATORS
Authors: MESSIAS MARCELO , NESPOLI CRISTIANE , BOTTA VANESSA A.
Published: April 2010

The memristor is supposed to be the fourth fundamental electronic element in addition to the well-known resistor, inductor and capacitor. Named as a contraction for memory resistor, its theoretical existence was postulated in 1971 by L. O. Chua, based on symmetrical and logical properties observed in some electronic circuits. On the other hand its physical realization was announced only recently in a paper published on May 2008 issue of Nature by a research team from Hewlett–Packard Company. In this work, we present the bifurcation analysis of two memristor oscillators mathematical models, given by three-dimensional five-parameter piecewise-linear and cubic systems of ordinary differential equations. We show that depending on the parameter values, the systems may present the coexistence of both infinitely many stable periodic orbits and stable equilibrium points. The periodic orbits arise from the change in local stability of equilibrium points on a line of equilibria, for a fixed set of parameter values. This phenomenon is a kind of Hopf bifurcation without parameters. We have numerical evidences that such stable periodic orbits form an invariant surface, which is an attractor of the systems solutions. The results obtained imply that even for a fixed set of parameters the two systems studied may or may not present oscillations, depending on the initial condition considered in the phase space. Moreover, when they exist, the amplitude of the oscillations also depends on the initial conditions.
GRAPH-THEORETIC CHARACTERIZATION OF BIFURCATION PHENOMENA IN ELECTRICAL CIRCUIT DYNAMICS
Authors: RIAZA RICARDO
Published: April 2010

This paper addresses bifurcation properties of equilibria in lumped electrical circuits. The goal is to tackle these properties in circuit-theoretic terms, characterizing the bifurcation conditions in terms of the underlying network digraph and the electrical features of the circuit devices. The attention is mainly focused on so-called singular bifurcations, resulting from the semistate (differential-algebraic) nature of circuit models, but the scope of our approach seems to extend to other types of bifurcations. The bifurcation analysis combines different tools coming from graph theory (such as proper trees in circuit digraphs, Maxwell's determinantal expansions or the colored branch theorem) with several results from linear algebra (matrix pencils, the Cauchy–Binet formula, Schur complements). Several examples illustrate the results.
A SIMPLE METHOD FOR FINDING TOPOLOGICAL HORSESHOES
Authors: LI QINGDU , YANG XIAO-SONG
Published: April 2010

This paper presents an efficient method for finding horseshoes in dynamical systems by using several simple results on topological horseshoes. In this method, a series of points from an attractor of a map (or a Poincaré map) are firstly computed. By dealing with the series, we can not only find the approximate location of each short unstable periodic orbit (UPO), but also learn the dynamics of almost every small neighborhood of the attractor under the map or the reverse map, which is very helpful for finding a horseshoe. The method is illustrated with the Hénon map and two other examples. Since it can be implemented with a computer software, it becomes easy to study the existence of chaos and topological entropy by virtue of topological horseshoe.
HETERODIMENSIONAL CYCLE BIFURCATION WITH ORBIT-FLIP
Authors: LU QIUYING , QIAO ZHIQIN , ZHANG TIANSI , ZHU DEMING
Published: April 2010

The local moving frame approach is employed to study the bifurcation of a degenerate heterodimensional cycle with orbit-flip in its nontransversal orbit. Under some generic hypotheses, we provide the conditions for the existence, uniqueness and noncoexistence of the homoclinic orbit, heteroclinic orbit and periodic orbit. And we also present the coexistence conditions for the homoclinic orbit and the periodic orbit. But it is impossible for the coexistence of the periodic orbit and the persistent heterodimensional cycle or the coexistence of the homoclinic loop and the persistent heterodimensional cycle. Moreover, the double and triple periodic orbit bifurcation surfaces are established as well. Based on the bifurcation analysis, the bifurcation surfaces and the existence regions are located. An example of application is also given to demonstrate our main results.
ANALYTICAL SOLUTIONS OF SYSTEMS WITH PIECEWISE LINEAR DYNAMICS
Authors: KOMINIS Y. , BOUNTIS T.
Published: April 2010

A class of nonautonomous dynamical systems, consisting of an autonomous nonlinear system and an autonomous linear periodic system, each acting by itself at different time intervals, is studied. It is shown that under certain conditions for the durations of the linear and the nonlinear time intervals, the dynamics of the nonautonomous piecewise linear system is closely related to that of its nonlinear autonomous component. As a result, families of explicit periodic, nonperiodic and localized breather-like solutions are analytically obtained for a variety of interesting physical phenomena.
ALMOST SURE EXPONENTIAL STABILITY OF STOCHASTIC RECURRENT NEURAL NETWORKS WITH TIME-VARYING DELAYS
Authors: WAN LI , ZHOU QINGHUA
Published: April 2010

The stability of stochastic recurrent neural networks with time-varying delays is investigated. A set of novel sufficient conditions on almost sure exponential stability has been established. Two examples are also given to illustrate the effectiveness of our results.
ON THE NONEQUIVALENCE OF LORENZ SYSTEM AND CHEN SYSTEM
Authors: HOU ZHENTING , KANG NING , KONG XIANGXING , CHEN GUANRONG , YAN GUOJUN
Published: April 2010

In this paper, we prove that the Chen system with a set of chaotic parameters is not smoothly equivalent to the Lorenz system with any parameters.
INTERPLAY BETWEEN CHAOS AND EXTERNAL NOISE IN AN EXTENDED SYSTEM: IMPROVED FORECASTING DUE TO INTRINSIC STOCHASTIC RESONANT PHENOMENA
Authors: REVELLI JORGE A. , RODRIGUEZ MIGUEL A. , WIO HORACIO S.
Published: April 2010

We have investigated the effects of noise on an extended chaotic system using as benchmark the Lorenz'96 model. The analysis of the system's time evolution and its time and space correlations show numerical evidence for two distinct stochastic resonance-like behaviors as a function of the external noise intensity, or the system size, and they result to be only weakly sensitive to an external periodic signal. The underlying mechanisms can be associated to a noise induced chaos reduction. A new view of the stochastic resonance phenomenon in a nonstationary situation is shown, studying the resonant phenomena implications in forecasting by exploiting a new method that quantifies the reduction of chaos error evolution process.
INFLUENCE OF SEDIMENTATION ON CONVECTIVE INSTABILITIES IN COLLOIDAL SUSPENSIONS
Authors: RYSKIN ANDREY , PLEINER HARALD
Published: April 2010

We investigate theoretically the bifurcation scenario for colloidal suspensions subject to a vertical temperature gradient taking into account the effect of sedimentation. In contrast to molecular binary mixtures, here the thermal relaxation time is much shorter than that for concentration fluctuations. This allows for differently prepared ground states, where a concentration profile due to sedimentation and/or the Soret effect has been established or not. This gives rise to different linear instability behaviors, which are manifest in the temporal evolution into the final, generally stationary convective state. In a certain range, above a rather high barometric number there is a coexistence between the quiescent state and the stationary convective one, allowing for a hysteretic scenario.
COMMUNITY DETECTION IN NETWORKS
Authors: DORSO C. O. , MEDUS A. D.
Published: April 2010

The problem of community detection is relevant in many disciplines of science. A community is usually defined, in a qualitative way, as a subset of nodes of a network which are more connected among themselves than to the rest of the network. In this article, we introduce a new method for community detection in complex networks. We define new merit factors based on the weak and strong community definitions formulated by Radicchi et al. [2004] and we show that this local definition properly describes the communities observed experimentally in two typical social networks.
MEAN FIELD APPROXIMATION FOR A STOCHASTIC PUBLIC GOODS GAME
Authors: DA SILVA ROBERTO , GUIDI LEONARDO FERNANDES , BARAVIERA ALEXANDRE
Published: April 2010

We consider a cellular automaton in the context of mean field approximation to model an interacting public goods game. In this game, players are offered to invest their money in a common pool and the profits are equally distributed among all participants irrespective of their contribution. In our version, players have a motivational level that controls the investment which is updated according to the profit obtained by each player due to two sources: a deterministic (risk free parameter) and a stochastic one (external noise). Analytical results are obtained to describe the stationary state of the average motivation level of the population for different initial conditions and Monte Carlo simulations are used to corroborate the theoretical results.
FINITE TEMPERATURE APPROACH TO QUANTUM PHASE TRANSITIONS
Authors: PLASTINO A. , CURADO E. M. F.
Published: April 2010

We show how ordinary, finite-temperature tools of Statistical Mechanics can be used to detect quantum phase transitions in many-body systems. In particular, statistical correlations exhibit a quite idiosyncratic behavior at the critical interaction-strengths. Moreover, what one may call "soft quantum phase-transitions" (crossings of excited states) are characterized by the rather special way of vanishing that these correlations adopt.
RISK INFORMED DECISION MAKING USING MULTIOBJECTIVE OPTIMIZATION TECHNIQUE
Authors: SRINIVAS G. , VERMA A. K. , SRIVIDYA A.
Published: April 2010

Nuclear Power Plant operations are guided by Limiting conditions of operations (LCO's) laid out in the document referred to as the Technical Specifications (TS). This Technical Specification is a legitimate framework approved by the Regulatory Bodies for the Safe operations of the Nuclear Power plants. In the past, the regulatory bodies used a deterministic approach as the basis for making decisions on safety issues and organizing the activities that they carry out. This was done by applying high level criteria such as the need to provide defence in depth and adequate safety margins. However with the availability of detailed Plant Specific Level-1 Probabilistic Safety Assessment (PSA), these limiting conditions need to be reviewed/revised based on the analysis results. This review of the LCO's is not a trivial exercise if the entire solution space of the variables defining the variables has to be investigated. This paper reviews the case for revision of Surveillance test frequencies of the Emergency Core Cooling System injection valves, using the multiobjective optimization technique.
EARLY QUALITATIVE SOFTWARE RELIABILITY PREDICTION AND RISK MANAGEMENT IN PROCESS CENTRIC DEVELOPMENT THROUGH A SOFT COMPUTING TECHNIQUE
Authors: MOHAN K. KRISHNA , VERMA A. K. , SRIVIDYA A.
Published: April 2010

A unique take on strengthening the role of a prototype of a software system without actually realizing it, would be to arrive at predictions using historical information from similar PoCs or the permeating experience of those involved in projects of comparable nature. Abundance of soft computing techniques should make this crucial bypassing feasible. The purpose of the this work is to demonstrate the same. Validation of this approach could be obtained by comparing the results with the ones obtained on realized prototypes at module level. In a work of the first of its kind involving studies at the PoC level, qualititave predictions for the metric 'number of defects' are obtained using a generic Fuzzy Logic based modeling. A sound mathematical base for the calculation of slopes of various Fuzzy membership functions employed is explained in detail for the case studies considered. This framework is applicable to any of the process oriented developmental systems like rational unified process. Pivotal risk management schemes are put forward. Significance of orthogonal defect classification method is explained in the context of the case study considered earlier.
HIERARCHICAL CLASSIFICATION OF GENE ONTOLOGY TERMS USING THE GOstruct METHOD
Authors: SOKOLOV ARTEM , BEN-HUR ASA
Published: April 2010

Protein function prediction is an active area of research in bioinformatics. Yet, the transfer of annotation on the basis of sequence or structural similarity remains widely used as an annotation method. Most of today's machine learning approaches reduce the problem to a collection of binary classification problems: whether a protein performs a particular function, sometimes with a post-processing step to combine the binary outputs. We propose a method that directly predicts a full functional annotation of a protein by modeling the structure of the Gene Ontology hierarchy in the framework of kernel methods for structured-output spaces. Our empirical results show improved performance over a BLAST nearest-neighbor method, and over algorithms that employ a collection of binary classifiers as measured on the Mousefunc benchmark dataset.
UNDERSTANDING DISTAL TRANSCRIPTIONAL REGULATION FROM SEQUENCE, EXPRESSION AND INTERACTOME PERSPECTIVES
Authors: RAO ARVIND , STATES DAVID J. , HERO ALFRED O. , ENGEL JAMES DOUGLAS
Published: April 2010

Gene regulation in eukaryotes involves a complex interplay between the proximal promoter and distal genomic elements (such as enhancers) which work in concert to drive precise spatio-temporal gene expression. The experimental localization and characterization of gene regulatory elements is a very complex and resource-intensive process. The computational identification of regulatory regions that confer spatiotemporally specific tissue-restricted expression of a gene is thus an important challenge for computational biology. One of the most popular strategies for enhancer localization from DNA sequence is the use of conservation-based prefiltering and more recently, the use of canonical (transcription factor motifs) or de novo tissue-specific sequence motifs. However, there is an ongoing effort in the computational biology community to further improve the fidelity of enhancer predictions from sequence data by integrating other, complementary genomic modalities.

In this work, we propose a framework that complements existing methodologies for prospective enhancer identification. The methods in this work are derived from two key insights: (i) that chromatin modification signatures can discriminate proximal and distally located regulatory regions and (ii) the notion of promoter-enhancer cross-talk (as assayed in 3C/5C experiments) might have implications in the search for regulatory sequences that co-operate with the promoter to yield tissue-restricted, gene-specific expression.
R2D: A FRAMEWORK FOR THE RELATIONAL TRANSFORMATION OF RDF DATA
Authors: RAMANUJAM SUNITHA , GUPTA ANUBHA , KHAN LATIFUR , THURAISINGHAM BHAVANI , SEIDA STEVEN
Published: April 2010

The astronomical growth of the World Wide Web has resulted in data explosion that in turn has given rise to a need for data representation methodologies and standards to present required information in a rapid and automated manner. The Resource Description Framework (RDF) is one such standard proposed by W3C to address the above need. The ubiquitous acceptance of RDF on the Internet has resulted in the emergence of a new data storage paradigm, the RDF Graph Model, which, as with any data storage methodology, requires data modeling and visualization tools to aid with data management. This paper presents R2D (RDF-to-Database), a relational wrapper for RDF Data Stores, which aims to transform, at run-time, semi-structured RDF data into an equivalent domain-specific relational schema, thereby bridging the gap between RDF and RDBMS concepts and making the abundance of relational tools currently in the market available to the RDF Stores. The primary R2D functionalities and mapping constructs, the high-level system architecture, and deployment flowchart are presented along with algorithms and performance graphs for every stage of the transformation process and screenshots of a relational visualization tool using R2D as evidence of the feasibility of the proposed work.
The interaction of deformation and metamorphic reactions
Authors: Hobbs Bruce E. , Ord Alison , Spalla Maria Iole , Gosso Guido , Zucali Michele
Published: April 2010

Feedback relations between deformation and metamorphic mineral reactions, derived using the principles of non-equilibrium thermodynamics, indicate that mineral reactions progress to completion in high-strain areas, driven by energy dissipated from inelastic deformation. These processes, in common with other time-dependent geological processes, lead to both strain, and strain-rate, hardening/softening in rate-dependent materials. In particular, strain-rate softening leads to the formation of shear zones, folds and boudins by non-Biot mechanisms. Strain-softening alone does not produce folding or boudinage and results in low-strain shear zones; strain-rate softening is necessary to produce realistic strains and structures. Reaction–mechanical feedback relations operating at the scale of 10–100 m produce structures similar to those that arise from thermal–mechanical feedback relations at coarser (kilometre) scales and reaction–diffusion–mechanical feedback relations at finer (millimetre) scales. The dominance of specific processes at various length scales but the development of similar structures by all coupled processes leads to scale invariance. The concept of non-equilibrium mineral stability diagrams is introduced. In principle, deformation influences the position of mineral stability fields relative to equilibrium stability fields; the effect is negligible for the
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reaction but may be important for others. Application of these results to the development of structures and mineral reactions in the Italian Alps is discussed.
Argon enters the retentive zone: reassessment of diffusion parameters for K-feldspar in the South Cyclades Shear Zone, Ios, Greece
Authors: Forster M. A. , Lister G. S.
Published: April 2010

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Ar apparent age spectra have been measured for unusually retentive potassium feldspars (K-feldspar) from the South Cyclades Shear Zone, Ios, Greece. Our results imply that the Argon Partial Retention Zone (Ar PRZ) for the most retentive domains in potassium K-feldspar can expand into the ductile regime, even when temperatures in excess of about 400–450 °C apply. In such cases K-feldspar could be used as a geochronometer to estimate the timing and duration of deformation and metamorphism events. Therefore, we have reassessed traditional methods used to analyse Arrhenius plots by simulating the effect of step-heating experiments on argon loss. Fractal multidomain diffusion models were used, with theoretical distributions of diffusion domain size and volume. We discovered a Fundamental Asymmetry Principle that offers objective constraints on slope fitting to allow an analysis to be consistent with the multidomain diffusion hypothesis, and which consistently leads to the estimation of higher activation energies. Reanalysis of existing datasets is encouraged to allow reassessment of the significance of the average values reported. Retentive diffusion parameters for K-feldspar might prove to be commonplace.
Versatile system-level memory-aware platform description approach for embedded MPSoCs
Authors: Pyka Robert , Klein Felipe , Marwedel Peter , Mamagkakis Stylianos
Published: April 2010

In this paper, we present a novel system modeling language which targets primarily the development of source-level multiprocessor memory aware optimizations.

In contrast to previous system modeling approaches this approach tries to model the whole system and especially the memory hierarchy in a structural and semantically accessible way. Previous approaches primarily support generation of simulators or retargetable code selectors and thus concentrate on pure behavioral models or describe only the processor instruction set in a semantically accessible way, A simple, database-like, interface is offered to the optimization developer, which in conjunction with the MACCv2 framework enables rapid development of source-level architecture independent optimizations.
Semi-automatic derivation of timing models for WCET analysis
Authors: Schlickling Marc , Pister Markus
Published: April 2010

Embedded systems are widely used for supporting our every day life. In the area of safety-critical systems human life often depends on the system's correct behavior. Many of such systems are hard real-time systems, so that the notion of correctness not only means functional correctness. They additionally have to obey stringent timing constraints, i.e. timely task completion under all circumstances is essential. An example for such a safety-critical system is the flight control computer in an airplane, which is responsible for stability, attitude and path control.

In order to derive guarantees on the timing behavior of hard real-time systems, the worst-case execution time (WCET) of each task in the system has to be determined. Saarland University and AbsInt GmbH have successfully developed the aiT WCET analyzer for computing safe upper bounds on the WCET of a task. The computation is mainly based on abstract interpretation of timing models of the processor and its periphery. Such timing models are currently hand-crafted by human experts. Therefore their implementation is a time-consuming and error-prone process.

Modern processors or system controllers are automatically synthesized out of formal hardware specifications like VHDL or Verilog. Besides the system' functional behavior, such specifications provide all information needed for the creation of a timing model. But due to their size and complexity, manually examining the sources is even more complex than only looking at the processor manuals. Moreover, this would not reduce the effort nor the probability of implementation errors.

To face this problem, this paper proposes a method for semi-automatically deriving suitable timing models out of formal hardware specifications in VHDL that fit to the tool chain of the aiT WCET analyzer. By this, we reduce the creation time of timing models from months to weeks.
Improving both the performance benefits and speed of optimization phase sequence searches
Authors: Kulkarni Prasad A. , Jantz Michael R. , Whalley David B.
Published: April 2010

The issues of compiler optimization phase ordering and selection present important challenges to compiler developers in several domains, and in particular to the speed, code size, power, and cost-constrained domain of embedded systems. Different sequences of optimization phases have been observed to provide the best performance for different applications. Compiler writers and embedded systems developers have recently addressed this problem by conducting iterative empirical searches using machine-learning based heuristic algorithms in an attempt to find the phase sequences that are most effective for each application. Such searches are generally performed at the program level, although a few studies have been performed at the function level. The finer granularity of function-level searches has the potential to provide greater overall performance benefits, but only at the cost of slower searches caused by a greater number of performance evaluations that often require expensive program simulations. In this paper, we evaluate the performance benefits and search time increases of function-level approaches as compared to their program-level counterparts. We, then, present a novel search algorithm that conducts distinct function-level searches simultaneously, but requires only a single program simulation for evaluating the performance of potentially unique sequences for each function. Thus, our new hybrid search strategy provides the enhanced performance benefits of function-level searches with a search-time cost that is comparable to or less than program-level searches.
An efficient code update scheme for DSP applications in mobile embedded systems
Authors: Li Weijia , Zhang Youtao
Published: April 2010

DSP processors usually provide dedicated address generation units (AGUs) to assist address computation. By carefully allocating variables in the memory, DSP compilers take advantage of AGUs and generate efficient code with compact size and improved performance. However, DSP applications running on mobile embedded systems often need to be updated after their initial releases. Studies showed that small changes at the source code level may significantly change the variable layout in the memory and thus the binary code, which causes large energy overheads to mobile embedded systems that patch through wireless or satellite communication, and often pecuniary burden to the users.

In this paper, we propose an update-conscious code update scheme to effectively reduce patch size. It first performs incremental offset assignment based on a recent variable coalescing heuristic, and then summarizes the code difference using two types of update primitives. Our experimental results showed that using update-conscious code update can greatly improve code similarity and thus reduce the update script sizes.
Sampling-based program execution monitoring
Authors: Fischmeister Sebastian , Ba Yanmeng
Published: April 2010

For its high overall cost during product development, program debugging is an important aspect of system development. Debugging is a hard and complex activity, especially in time-sensitive systems which have limited resources and demanding timing constraints. System tracing is a frequently used technique for debugging embedded systems. A specific use of system tracing is to monitor and debug control-flow problems in programs. However, it is difficult to implement because of the potentially high overhead it might introduce to the system and the changes which can occur to the system behavior due to tracing. To solve the above problems, in this work, we present a sampling-based approach to execution monitoring which specifically helps developers debug time-sensitive systems such as real-time applications. We build the system model and propose three theorems to determine the sampling period in different scenarios. We also design seven heuristics and an instrumentation framework to extend the sampling period which can reduce the monitoring overhead and achieve an optimal tradeoff between accuracy and overhead introduced by instrumentation. Using this monitoring framework, we can use the information extracted through sampling to reconstruct the system state and execution paths to locate the deviation.