bluuebunny/crossref_metadata_2025 huggingface dataset:
Vesicular cells of the lodgepole pine dwarf mistletoe (Arceuthobium americanum) fruit: development, cytochemistry, and lipid analysis
Authors: Kelly Shannon K. , Ross Friedman Cynthia M. , Smith Ron G.
Published: December 2009

The lodgepole pine dwarf mistletoe, Arceuthobium americanum Nutt. ex Engelm., is a parasitic angiosperm that infects conifers in western Canadian forests. A striking feature of the Arceuthobium life cycle is explosive seed dispersal, triggered by hydrostatic build-up within the fruit, localized in a tissue called “viscin.” Viscin is composed of two cell types: “viscin cells” that accrue pressure in their hydrated mucilage, and “vesicular cells” with a previously undetermined function. The objective of this work was to investigate the development and composition of vesicular cells using microscopy, cytochemistry, and gas chromatography – mass spectroscopy. We found that vesicular cells are initiated from mesocarp cells lining the viscin cells. As development of the seed progresses, vesicular cells form a single layer, enlarge, and become isodiametric. Later, the cells make up all of the remaining 3–4 outer mesocarp layers. Concomitant with enlargement, intracellular triacylglycerides (TAGs) largely composed of 16-carbon and 18-carbon fatty acids, accumulate. Immediately prior to discharge, vesicular cell boundaries become indistinct, and the cell contents become confluent, creating a lipid mass between the viscin cells and the exocarp. Vesicular cells and their resulting lipid mass likely function in discharge by acting as a hydrophobic barrier to water loss and (or) as a repellant, resistant layer.
Topology of thermogenic tissues ofAlocasia macrorrhizos(Araceae) inflorescences
Authors: Ivancic Anton , Roupsard Olivier , Quero-García José , Sisko Metka , Urbanek Krajnc Andreja , Lebot Vincent
Published: December 2009

Thermogenesis and heat generating tissues in inflorescences of the giant taro ( Alocasia macrorrhizos (L.) G. Don) were studied from December 2005 to February 2006, on the Island of Espiritu Santo, Vanuatu. Temperatures were recorded in the ambient air, in the peduncle tissue, and on 12 positions within spadices during periods of maximum thermogenic activity, in the early morning hours of the female and male phases. The study showed that there were three thermogenic tissues: the sterile appendix, the fertile male part, and the differentiated sterile area below the fertile male part. During the female phase, heat was generated by the sterile appendix and the differentiated sterile area below the fertile male part, the smallest region of the spadix (mean ± SD = 0.86 ± 0.24 cm, 3.17% of the spadix length), and most probably by the fertile male part. Within the spadix, average temperatures gradually increased from the base of the female part and reached the first peak at the midpoint of the differentiated sterile area below the fertile male part (36.11 ± 1.54 °C). After that, they gradually decreased towards the midpoint of the fertile male part and increased again, reaching a second (main) peak at 1/4 of the sterile appendix height (44.83 ± 1.87 °C). From 1/4 to 1/2 of the appendix height they remained at more or less the same level, and then they decreased towards the tip of the spadix. During the male phase, heat was generated only within the fertile male part.
Hydrodynamics of a large oil sand tailings impoundment and related environmental implications
Authors: Ferguson G. P. , Rudolph D. L. , Barker J. F.
Published: December 2009

Oil sand mine tailings are primarily contained by dykes constructed of permeable sand tailings. The environmental impacts of process waters released from these tailings facilities are controlled by groundwater flow within the impoundment structures. Transient groundwater flow characteristics were assessed within the Tar Island Dyke structure at the Suncor Inc. site near Fort McMurray, Alberta, to assist in quantifying potential long-term environmental impacts. A sequence of low-permeability fine tailings underlying the tailings water pond is supported by coarse sand tailings that are connected to and form the containment dyke structure. A clay unit separates the foundation from the underlying limestone that is hydraulically connected to the Athabasca River. The primary groundwater flow pathways are through the toe of the dyke and through the foundation. Field data and numerical simulations indicate that drainage of process water within the structure remains transient yet decreases over time. The fine tailings and pond become perched atop unsaturated coarse tailings, significantly restricting seepage and producing an environmental legacy with reclamation implications. The release of potentially contaminated process water continues to decrease, resulting in diminishing environmental risk. The lowering of pore-water pressures within the main dyke has increased its strength and long-term stability.
Wetting front advancing column test for measuring unsaturated hydraulic conductivity
Authors: Li X. , Zhang L. M. , Fredlund D. G.
Published: December 2009

Unsaturated hydraulic conductivity is the primary soil parameter required when performing seepage analyses for unsaturated–saturated soil systems. Unsaturated hydraulic conductivity is also one of the most difficult parameters to measure because of the time involved and the limited suction measurement range (e.g., 0∼1500 kPa in a test using the steady-state method). In this study, a new wetting front advancing method was developed for measuring unsaturated hydraulic conductivity. The wetting front advancing method simulates and monitors a soil wetting process through a large-scale soil column. A new interpretative procedure was developed to calculate the unsaturated hydraulic conductivity based on the monitored water content, suction, and wetting front advancing velocity. The proposed technique is used to measure the unsaturated hydraulic conductivities of five soils, which vary from gravel to clay. The results indicate that the proposed technique is time-saving (i.e., requires several days for a complete test) and is applicable over wide ranges of suctions and unsaturated hydraulic conductivities. The measured unsaturated hydraulic conductivity using the wetting front advancing method is similar to that obtained using the instantaneous profile method, with the latter covering narrower ranges of soil suction and hydraulic conductivity.
NON-UNIFORM "FAT-MESHES" FOR CHIP MULTIPROCESSORS
Authors: ZHANG YU , JONES ALEX K.
Published: December 2009

This paper studies the traffic hot spots of mesh networks in the context of chip multiprocessors. To mitigate these effects, this paper describes a non-uniform fat-mesh extension to mesh networks, which are popular for chip multiprocessors. The fat-mesh is inspired by the fat-tree and dedicates additional links for connections with heavy traffic (e.g. near the center) with fewer links for lighter traffic (e.g. near the periphery). Two fat-mesh schemes are studied based on the traffic requirements of chip multiprocessors using dimensional ordered XY routing and a randomized XY-YX routing algorithms, respectively. Analytical fat-mesh models are constructed by theoretically presenting the expressions for the traffic requirements of personalized all-to-all traffic for both the raw message numbers and their normalized equivalents. We demonstrate how traffic scales for a traditional mesh compared to a non-uniform fat mesh. Simulation results demonstrate that using same number of physical links the non-uniform fat-mesh can achieve better performance than a uniform fat-mesh mesh using both synthetic traffic patterns and splash-2 benchmark traces.
DEEPLY VIRTUAL COMPTON SCATTERING AT SMALL xBj
Authors: MÜLLER DIETER , KUMERIČKI KREŠIMIR
Published: December 2009

We analyze small-x deeply virtual Compton scattering data using flexible generalized parton distribution models to pin down both the skewness and t dependence. We compare our outcome at t = 0 with the full Shuvaev transformation. We point out that this integral transform is a model which is equivalent to a conformal generalized parton distribution and a minimalist "dual" parameterization. Some mathematical subtleties of conformal representations are recalled.
NON-UNIVERSALITY AND EVOLUTION OF THE SIVERS FUNCTION
Authors: RATCLIFFE PHILIP G. , TERYAEV OLEG
Published: December 2009

We examine the large-x QCD evolution of the twist-three gluonic-pole strength defining an effective T -odd Sivers function, where evolution of the T -even transverse-spin DIS structure function g2 is multiplicative. The result corresponds to a colour-factor modified spin-averaged twist-two evolution.
LONGITUDINALLY POLARIZED HADRO- AND PHOTOPRODUCTION OF HEAVY QUARKS
Authors: RIEDL JOHANN
Published: December 2009

Measurements of double-spin asymmetries for single-inclusive heavy flavor production and for heavy quark correlations are expected to provide valuable information about the spin structure of the nucleon, in particular, the elusive gluon polarization. We discuss progress towards a versatile parton-level Monte-Carlo code for the production and decay of heavy quarks in longitudinally polarized hadron-hadron and photon-hadron collisions at next-to-leading order accuracy of QCD. Phenomenological studies are presented for BNL-RHIC and COMPASS.
BINARY CHAOS SYNCHRONIZATION IN ELEMENTARY CELLULAR AUTOMATA
Authors: DOGARU RADU , DOGARU IOANA , KIM HYONGSUK
Published: December 2009

It is shown that 8 of all 256 elementary cellular automata have the property of chaos synchronization using a binary driving sequence. The binary synchronization signal ensures good noise robustness. A simple measure for characterizing long periodic cycles as being "chaotic" was introduced. It is also shown that certain relations between the profile of attractors shaped by the local rule in the finite state space and the property of chaos synchronization exists. A simple modulation–demodulation scheme is proposed allowing to build spread spectrum communication links at low implementation costs while the cellular automata state space (number of cells) can be taken as large as required by cryptographic reasons.
ON LOCALIZATIONS IN MINIMAL CELLULAR AUTOMATA MODEL OF TWO-SPECIES MUTUALISM
Authors: ADAMATZKY ANDREW , GRUBE MARTIN
Published: December 2009

A mutualism is an interaction where the involved species benefit from each other. We study a two-dimensional hexagonal three-state cellular automaton model of a two-species mutualistic system. The simple model is characterized by four parameters of propagation and survival dependencies between the species. We map the parametric set onto the basic types of space-time structures that emerge in the mutualistic population dynamic. The structures discovered include propagating quasi-one-dimensional patterns, very slowly growing clusters, still and oscillatory stationary localizations. Although we hardly find such idealized patterns in nature, due to inreased complexity of interaction phenomena, we recognize our findings as basic spatial patterns of mutualistic systems, which can be used as baseline to build up more complex models.
DYNAMIC BEHAVIOR OF A STEADY FLOW IN AN ANNULAR TUBE WITH POROUS WALLS AT DIFFERENT TEMPERATURES
Authors: HONA JACQUES , NYOBE ELISABETH NGO , PEMHA ELKANA
Published: December 2009

In this paper, the axisymmetric flow of a viscous fluid through a porous annular tube with walls kept at different temperatures is studied theoretically. The physical properties of the fluid remain constant, notably its specific mass, its dynamic viscosity and its thermal diffusivity. The nondimensional parameters which the solutions of the problem depend on are defined. A numerical integration using the shooting method is applied for solving the Navier–Stokes equations and the energy equation. Bifurcation diagrams are presented and enable to highlight significant properties of the flow. Some thermal behaviors corresponding to specific values of the parameters are performed. Asymmetric solutions of the steady flow are described and some results about velocity components are also analyzed.
NONDEGENERATE UMBILICS, THE PATH FORMULATION AND GRADIENT BIFURCATION PROBLEMS
Authors: FURTER JACQUES-ELIE , SITTA ANGELA MARIA
Published: December 2009

Parametrized contact-equivalence is a successful theory for the understanding and classification of the qualitative local behavior of bifurcation diagrams and their perturbations. Path formulation is an alternative point of view making explicit the singular behavior due to the core of the bifurcation germ (when the parameters vanish) from the effects of the way parameters enter. We show how to use path formulation to classify and structure efficiently multiparameter bifurcation problems in corank 2 problems. In particular, the nondegenerate umbilics singularities are the generic cores in four situations: the general or gradient problems, with or without ℤ2 symmetry where ℤ2 acts on the second component of ℝ2 via κ(x,y) = (x,-y). The universal unfolding of the umbilic singularities have an interesting "Russian doll" type of structure of miniversal unfoldings in all those categories.

With the path formulation approach we can handle one, or more, parameter situations using the same framework. We can even consider some special parameter structure (for instance, some internal hierarchy of parameters). We classify the generic bifurcations with 1, 2 or 3 parameters that occur in those cases. Some results are known with one bifurcation parameter, but the others are new. We discuss some applications to the bifurcation of a loaded cylindrical panel. This problem has many natural parameters that provide concrete examples of our generic diagrams around the first interaction of the buckling modes.
A FAST CONTROL METHOD BASED ON STABLE MANIFOLD INFORMATION
Authors: HILL D. L.
Published: December 2009

A method of greatly decreasing the activation time of a control method based on stable manifold information is proposed.
BIFURCATIONS AND CHAOS IN A PERIODICALLY PROBED COMPUTER NETWORK
Authors: FROMMER IAN , HARDER ERIC , HUNT BRIAN , LANCE RYAN , OTT EDWARD , YORKE JAMES
Published: December 2009

In this paper we model a computer network consisting of one standard Internet connection and one nonstandard connection that transmits uniformly sized bursts of packets at regular intervals. The nonstandard connection can represent probing activity of either a diagnostic measurement or attack. Using bifurcation diagrams, we study how the network's behavior changes as a function of the probing frequency. These diagrams reveal interesting, nonintuitive behavior. We present a series of models of increasing simplicity that capture the significant features of the network's behavior. Our simplest model is a piecewise linear, discontinuous one-dimensional map. This map helps explain the structure of the bifurcation diagram, and allows us to directly determine Lyapunov exponents, which give a measure of the system's predictability. As a result, we are able to more precisely describe and categorize the dynamics, including chaos, exhibited by this network.
SHADOWING AND DYNAMICAL SYNTHESIS
Authors: AKHMET M. U.
Published: December 2009

We discuss a system with a discontinuity moments generator to obtain the solutions. It is proven that the system is chaotic and has shadowing property [Anosov, 1967; Bowen, 1975; Hammel et al., 1987; Robinson, 1995] if the generator possesses these characteristics. Illustrative examples are provided.
CHAOTIC DYNAMICS OF LASER DIODES WITH STRONGLY MODULATED OPTICAL INJECTION
Authors: CHAN SZE-CHUN , TANG WALLACE K. S.
Published: December 2009

In this paper, a modulated optical injection system is proposed. It mainly consists of a semiconductor laser subject to a modulated optical injection. It is known that optical injection will force a laser intensity into high-speed periodic oscillation without modulation, while the oscillation will be locked with weak external modulation. However, the route to chaos in such a system is observed and reported for the first time. It is shown that the generated oscillation frequency shifts away from the external frequency when the modulation amplitude becomes sufficiently large. Due to the nonlinearities of the laser, the frequencies are mixed inside the laser cavity, which causes the dynamics to follow a quasi-periodic route to chaos. In addition, the resultant chaotic signal possesses a larger bandwidth than that attainable with constant optical injection alone. Since the system is capable of generating both narrowband photonic microwave signals with low phase variances and chaotic signals with large bandwidths, it is practically important for Doppler and chaotic lidar applications.
BOUNDS FOR THE DOMAIN CONTAINING ALL COMPACT INVARIANT SETS OF THE SYSTEM MODELING DYNAMICS OF ACOUSTIC GRAVITY WAVES
Authors: STARKOV KONSTANTIN E.
Published: December 2009

In this paper, we study the localization problem of compact invariant sets of the system modeling the dynamics of acoustic gravity waves constructed by Stenflo (the Lorenz–Stenflo system). We discuss relations between compact localization domains and trapping domains with the help of extended invariance principle due to Rodrigues et al. Based on this analysis, we compute the trapping domain for the system modeling the dynamics of acoustic gravity waves. By using the first order extremum conditions and a comparison with localization results obtained earlier for the Lorenz system we find that all compact invariant sets of the Lorenz–Stenflo system are located in the intersection of one-parameter set of ellipsoids with a few domains bounded by some quadratic surfaces. Further, we derive polytopic bounds for the locus of compact invariant sets. Finally, we present the general formulae validating the application of rational localizing functions and use these formulae for the Lorenz–Stenflo system and for the Lorenz system.
INFORMATION ENTROPY AND NONLINEAR SEMIQUANTUM DYNAMICS
Authors: SARRIS C. M. , PROTO ARACELI N.
Published: December 2009

We describe how, departing from the Shannon entropy, it is possible to deal with semiquantum time-independent nonlinear Hamiltonians. The interplay between the quantal and classical degrees of freedom can be easily seen, and the set of differential equations that govern the temporal evolution of the quantal mean values and the classical variables is obtained. We find invariants of motion and, particularly, we describe under which conditions, the uncertainty principle remains as an invariant of motion too. Through the analysis of these invariants, it is possible to follow the transition of the system from quantum to classical regime and to conclude that the uncertainty principle behaves as an indicator telling us whether the system is in regular or irregular regime. A simple example is shown.
CONFIGURATIONAL TEMPERATURE FOR INTERACTING ANISOTROPIC MAGNETIC PARTICLES
Authors: DÍAZ PABLO , LAROZE DAVID
Published: December 2009

We study by means of the Landau–Lifshitz equation both the dynamical and the thermodynamical equilibrium properties of the interacting anisotropic magnetic particles on a chain in the presence of an applied magnetic field. The interaction between the magnetic particles is produced by an exchange coupling between first neighbors with periodic boundary conditions. We find that the total magnetization modulus can be a fluctuating function of time, since the system under study contains anisotropic terms. We obtain an analytical expression for the configurational temperature and an approximate formula for the case of a large number of particles. When the direction of the external field is different to the easy axes, the configurational temperature presents an oscillatory behavior as a function of time. Finally, by using the time average of the temperature, we calculate both the energy and the magnetization along the external field as a function of temperature, recovering the equilibrium thermodynamics results.
SELF-REPLICATION AND LOCALIZED STRUCTURES INTERACTION IN A NONLOCAL MODEL OF POPULATION DYNAMICS
Authors: ESCAFF DANIEL
Published: December 2009

A particular type of localized structure in a prototypical model for population dynamics interaction is studied. The model considers cooperative and competitive interaction among the individuals. Interaction at distance (or nonlocal interaction) and a simple random walk for the motion of the individuals are included. The system exhibits the formation of a periodic cellular pattern in some region of its parameter space. Inside this parameter region, it is possible to observe the localization of a single cell from the cellular pattern into an unpopulated background. The stability of this localized structure is discussed, as well as the destabilization process that gives rise to its own self-replication, inducing the propagation of the cellular pattern. The long distance interaction between these localized structures is also studied which results in a mutual repulsion.
STOCHASTIC SEARCH PROCESSES AND CHEMICAL REACTIVITY IN HETEROGENEOUS MEDIA
Authors: MOREAU M. , BÉNICHOU O. , LOVERDO C. , VOITURIEZ R.
Published: December 2009

Intermittent search processes alternate between two different stochastic motions in order to reach a given target. If the faster motion has a lower probability to detect the target, a question arises concerning the efficiency of both processes, and it may be possible to minimize the search time by a convenient choice of the parameters. This argument has been used to interpret observations in molecular biology or to explain the behavior of animals when searching for food. It can also have interesting consequences for the kinetics of reactions in heterogeneous media. In particular, the reaction kinetics in a biological cell can be enhanced when the active molecules occasionally bind to molecular motors that inactivate their reactivity and carry them far away. Here, we present a synthesis of the recent results obtained on these topics, with new perspectives and possible applications of intermittent behavior in reaction kinetics to be soon developed.
GRANULAR FLOW MODELS AND DILATION FRONT PROPAGATION APPLIED TO UNDERGROUND MINING
Authors: VIVANCO FRANCISCO , MELO FRANCISCO , FUENTES CLAUDIO
Published: December 2009

Underground mining has become a viable alternative method for ore extraction when the operation cost of an open pit mine becomes too high. Its success is based on a good characterization of the rocks flow inside the cave. Kinematic and plasticity models, used in the granular flow description in hoppers, have been adapted to describe the experimental situations aimed at sketching the mine operation. The local packing changes that occur at the early stages of rock motion that significantly affect the flow are considered by introducing a dilation front propagating upward. The dynamics of the dilation front limits the extent of the flow generated by the drawing process allowing the assessment of the loosening zone. Based on the linear character of the kinematic model, it is shown that the loosening zone resulting from the simultaneous extraction at two adjacent draw points is accurately described by the dilation front approach.
IN VIVO NEAR-INFRARED FLUORESCENCE IMAGING OF HUMAN COLON ADENOCARCINOMA BY SPECIFIC IMMUNOTARGETING OF A TUMOR-ASSOCIATED MUCIN
Authors: DACOSTA RALPH S. , TANG YING , KALLIOMAKI TUULA , REILLY RAYMOND M. , WEERSINK ROBERT , ELFORD ALISHA R. , MARCON NORMAN E. , WILSON BRIAN C.
Published: December 2009

Background and Aims: Accurate endoscopic detection of premalignant lesions and early cancers in the colon is essential for cure, since prognosis is closely related to lesion size and stage. Although it has great clinical potential, autofluorescence endoscopy has limited tumor-to-normal tissue image contrast for detecting small preneoplastic lesions. We have developed a molecularly specific, near-infrared fluorescent monoclonal antibody (CC49) bioconjugate which targets tumor-associated glycoprotein 72 (TAG72), as a contrast agent to improve fluorescence-based endoscopy of colon cancer. Methods: The fluorescent anti-TAG72 conjugate was evaluated in vitro and in vivo in athymic nude mice bearing human colon adenocarcinoma (LS174T) subcutaneous tumors. Autofluorescence, a fluorescent but irrelevant antibody and the free fluorescent dye served as controls. Fluorescent agents were injected intravenously, and in vivo whole body fluorescence imaging was performed at various time points to determine pharmacokinetics, followed by ex vivo tissue analysis by confocal fluorescence microscopy and histology. Results: Fluorescence microscopy and histology confirmed specific LS174T cell membrane targeting of labeled CC49 in vitro and ex vivo. In vivo fluorescence imaging demonstrated significant tumor-to-normal tissue contrast enhancement with labeled-CC49 at three hours post injection, with maximum contrast after 48 h. Accumulation of tumor fluorescence demonstrated that modification of CC49 antibodies did not alter their specific tumor-localizing properties, and was antibody-dependent since controls did not produce detectable tumor fluorescence. Conclusions: These results show proof-of-principle that our near-infrared fluorescent-antibody probe targeting a tumor-associated mucin detects colonic tumors at the molecular level in real time, and offer a basis for future improvement of image contrast during clinical fluorescence endoscopy.
The Lower Palaeozoic palaeogeographical evolution of the northeastern and eastern peri-Gondwanan margin from Turkey to New Zealand
Authors: Torsvik Trond H. , Cocks L. Robin M.
Published: December 2009

In Lower Palaeozoic times, Gondwana was by far the largest tectonic entity, stretching from the South Pole to north of the Equator, and is termed a superterrane. We consider the northeastern sector of the Gondwanan and peri-Gondwanan margin, from Turkey through the Middle East, the north of the Indian subcontinent, southern China and SE Asia, to Australia and New Zealand. There was progressive tectonic activity along some of its margins during the period, with areas such as southeastern Australia undergoing enlargement through the accretion of island arcs as that part of Gondwana rotated. However, most of the area, from the Taurides of Turkey to at least east of India, represented a passive margin for the whole of the Lower Palaeozoic. Other adjacent areas, such as the Pontides of Turkey and Annamia (Indochina), were separate from the main Gondwanan craton as independent terranes. The quality and quantity of available data on Lower Palaeozoic rocks and faunas varies enormously over different parts of this substantial area, and there are few or no detailed palaeomagnetic data available for most of it. Some workers have considered the string of terranes from Armorica to the Malaysia Peninsula as having left Gondwana together in the late Cambrian as a Hun superterrane, leaving a widening Palaeotethys Ocean between it and Gondwana. However, we consider that the Palaeotethys opened no earlier than in late Silurian time (with Armorica and other terranes to its north), and that the Hun superterrane was not a cohesive unity. Other researchers vary in presenting many substantial Central Asian and Far Eastern terranes, including North China, South China, Tarim, Annamia and others, as integral parts of core Gondwana and not leaving it until Devonian and later times. We conclude that North China, Tarim and Annamia, among others, were probably not attached to core Gondwana in the Lower Palaeozoic, that South China was close to Gondwana (but not an integral part of it), and that Sibumasu was probably part of Gondwana. We try to reconcile the very varied published geological data and opinions, and present new palaeogeographical maps for that sector of Gondwana and surrounding areas for the Cambrian (500 Ma), Ordovician (480 Ma) and Silurian (425 Ma).
Avalonia: a long-lived terrane in the Lower Palaeozoic?
Authors: Cocks L. R. M. , Fortey R. A.
Published: December 2009

Avalonia was undoubtedly an independent terrane throughout the Ordovician, merging with Baltica at about Ordovician–Silurian boundary times (443 Ma). We consider it to have been internally unified throughout the Lower Palaeozoic, and not the two independent ‘East’ and ‘West’ Avalonian terranes of some authors. In the early Ordovician its faunas were certainly Gondwanan. However, its earlier history is controversial: we discuss whether Avalonia split off from Gondwana in the early Ordovician, or whether it left Gondwana in the late Neoproterozoic. We conclude that the varied basement terranes underlying Avalonia were aggregated to the margin of Gondwana before 650 Ma. Some substantial transform movements occurred along the Gondwanan margin between 610 and 530 Ma, but the Avalonian area remained part of core Gondwana until about the end of the Cambrian (490 Ma), when the rift–drift initiation of the opening Rheic Ocean between Gondwana and Avalonia began.
Ordovician life around the Celtic fringes: diversifications, extinctions and migrations of brachiopod and trilobite faunas at middle latitudes
Authors: Harper David A. T. , Owen Alan W. , Bruton David L.
Published: December 2009

During the early to mid-Ordovician, marine life experienced an unprecedented rise in diversity at the species, genus and family levels that firmly installed the suspension-feeding benthos as the main component of the Palaeozoic fauna. The earlier Ordovician was characterized by a wide dispersal of the continents together with a high frequency of microcontinents and volcanic arcs. Magmatic and tectonic activity was intense, climates were warm and sea levels were high. Central to the entire diversification is the role of gamma (inter-provincial) diversity and by implication the spread of the continents and frequency of island arcs and microcontinents. A disparate group of continental fragments and island arcs loosely assigned to the Celtic province contained distinctive shelly faunas that formed a testable biogeographical unit. The Celtic faunas are characterized by a large number of endemic brachiopod taxa, some cosmopolitan forms, and taxa at the beginning or end of their stratigraphical ranges. The associated trilobite faunas are composed largely of wide-ranging genera, a few genera at the start of their stratigraphical range and some recently evolved taxa extending their geographical range. The Celtic province helped provide a burst of gamma diversity during the early stages of the Ordovician Radiation whereas the timing and position of the archipelagos associated with the Celtic province may have provided a mechanism for the diachroneity associated with the diversification.
A survey of attack and defense techniques for reputation systems
Authors: Hoffman Kevin , Zage David , Nita-Rotaru Cristina
Published: December 2009

Reputation systems provide mechanisms to produce a metric encapsulating reputation for a given domain for each identity within the system. These systems seek to generate an accurate assessment in the face of various factors including but not limited to unprecedented community size and potentially adversarial environments.

We focus on attacks and defense mechanisms in reputation systems. We present an analysis framework that allows for the general decomposition of existing reputation systems. We classify attacks against reputation systems by identifying which system components and design choices are the targets of attacks. We survey defense mechanisms employed by existing reputation systems. Finally, we analyze several landmark systems in the peer-to-peer domain, characterizing their individual strengths and weaknesses. Our work contributes to understanding (1) which design components of reputation systems are most vulnerable, (2) what are the most appropriate defense mechanisms and (3) how these defense mechanisms can be integrated into existing or future reputation systems to make them resilient to attacks.
Face poser
Authors: Lau Manfred , Chai Jinxiang , Xu Ying-Qing , Shum Heung-Yeung
Published: December 2009

This article presents an intuitive and easy-to-use system for interactively posing 3D facial expressions. The user can model and edit facial expressions by drawing freeform strokes, by specifying distances between facial points, by incrementally editing curves on the face, or by directly dragging facial points in 2D screen space. Designing such an interface for 3D facial modeling and editing is challenging because many unnatural facial expressions might be consistent with the user's input. We formulate the problem in a maximum a posteriori framework by combining the user's input with priors embedded in a large set of facial expression data. Maximizing the posteriori allows us to generate an optimal and natural facial expression that achieves the goal specified by the user. We evaluate the performance of our system by conducting a thorough comparison of our method with alternative facial modeling techniques. To demonstrate the usability of our system, we also perform a user study of our system and compare with state-of-the-art facial expression modeling software (Poser 7).
Topology- and error-driven extension of scalar functions from surfaces to volumes
Authors: Patanè Giuseppe , Spagnuolo Michela , Falcidieno Bianca
Published: December 2009

The behavior of a variety of phenomena measurable on the boundary of 3D shapes is studied by modeling the set of known measurements as a scalar functionf:P → R, defined on a surface P. Furthermore, the large amount of scientific data calls for efficient techniques to correlate, describe, and analyze this data. In this context, we focus on the problem of extending the measures captured by a scalar functionf, defined on the boundary surface P of a 3D shape, to its surrounding volume. This goal is achieved by computing a sequence of volumetric functions that approximatefup to a specified accuracy and preserve its critical points. More precisely, we compute a smooth mapg: R3→ R such that the piecewise linear functionh:=gP : P → R, which interpolates the values ofgat the vertices of the triangulated surface P, is an approximation offwith the same critical points. In this way, we overcome the limitation of traditional approaches to function approximation, which are mainly based on a numerical error estimation and do not provide measurements of the topological and geometric features off. The proposed approximation scheme builds on the properties offrelated to itsglobal structure, that is, its critical points, and ignores the local details off, which can be successively introduced according to the target approximation accuracy.
Edge-based image coarsening
Authors: Fattal Raanan , Carroll Robert , Agrawala Maneesh
Published: December 2009

This article presents a new dimensionally-reduced linear image space that allows a number of recent image manipulation techniques to be performed efficiently and robustly. The basis vectors spanning this space are constructed from a scale-adaptive image decomposition, based on kernels of the bilateral filter. Each of these vectors locally binds together pixels in smooth regions and leaves pixels across edges independent. Despite the drastic reduction in the number of degrees of freedom, this representation can be used to perform a number of recent gradient-based tonemapping techniques. In addition to reducing computation time, this space can prevent the bleeding artifacts which are common to Poisson-based integration methods. In addition, we show that this reduced representation is useful for energy-minimization methods in achieving efficient processing and providing better matrix conditioning at a minimal quality sacrifice.
Interactive generation of human animation with deformable motion models
Authors: Min Jianyuan , Chen Yen-Lin , Chai Jinxiang
Published: December 2009

This article presents a new motion model
deformable motion models
for human motion modeling and synthesis. Our key idea is to apply statistical analysis techniques to a set of precaptured human motion data and construct a low-dimensional deformable motion model of the form x =
M
(α, γ), where the deformable parameters α and γ control the motion's geometric and timing variations, respectively. To generate a desired animation, we continuously adjust the deformable parameters' values to match various forms of user-specified constraints. Mathematically, we formulate the constraint-based motion synthesis problem in a Maximum A Posteriori (MAP) framework by estimating the most likely deformable parameters from the user's input. We demonstrate the power and flexibility of our approach by exploring two interactive and easy-to-use interfaces for human motion generation: direct manipulation interfaces and sketching interfaces.
A generic linked list implementation in Fortran 95
Authors: Blevins Jason R.
Published: December 2009

This paper develops a standard conforming generic linked list in Fortran 95 which is capable of storing data of any type. The list is implemented using the transfer intrinsic function, and although the interface is generic, it remains relatively simple and minimizes the potential for error. Although linked lists are the focus of this paper, the generic programming techniques used are very general and broadly-applicable to other data structures and procedures implemented in Fortran 95 that need to be used with data of an unknown type.
Language-based security on Android (abstract only)
Authors: Chaudhuri Avik
Published: December 2009

In this paper, we initiate a formal study of security on Android: Google's new open-source platform for mobile devices. Specifically, we present a core typed language to describe Android applications, and to reason about their data-flow security properties. Our operational semantics and type system provide some necessary foundations to help both users and developers of Android applications deal with their security concerns.
ActionScript bytecode verification with co-logic programming (abstract only)
Authors: DeVries Brian W. , Gupta Gopal , Hamlen Kevin W. , Moore Scott , Sridhar Meera
Published: December 2009

A prototype security policy verification system for ActionScript binaries is presented, whose implementation leverages recent advances in co-logic programming. Our experience with co-logic programming indicates that it is an extremely useful paradigm for elegantly expressing algorithms that lie at the heart of model-checking technologies. This results in an unusually small trusted computing base, making the verification system well-suited to frameworks like certifying in-lined reference monitoring systems, which require small, light-weight verifiers. Preliminary experiments and progress are discussed.
Encoding information flow in AURA (abstract only)
Authors: Jia Limin , Zdancewic Steve
Published: December 2009

Two of the main ways to protect security-sensitive resources in computer systems are to enforce access-control policies and information-flow policies. In this paper, we show how to enforce information-flow policies in AURA, which is a programming language for access control. When augmented with this mechanism for enforcing information-flow polices, AURA can further improve the security of reference monitors that implement access control.

We show how to encode security types and lattices of security labels using AURA's existing constructs for authorization logic. We prove a noninterference theorem for this encoding. We also investigate how to use expressive access-control policies specified in authorization logic as the policies for information declassification.
Catch me if you can
Authors: Askarov Aslan , Sabelfeld Andrei
Published: December 2009

Program errors are a source of information leaks. Tracking these leaks is hard because error propagation breaks out of program structure. Programming languages often feature exception constructs to provide some structure to error handling: for example, the try...catch blocks in Java and Caml. Mainstream information-flow security compilers such as Jif and FlowCaml enforce rigid rules for exceptions in order to prevent leaks via public side effects of computation whose reachability depends on exceptions.

This paper presents a general and permissive alternative to the rigid solution: the programmer is offered a choice for each type of error/exception whether to handle it or not. The security mechanism ensures that, in the former case, it is never handled and, in the latter case, it is always handled with the mainstream restrictions. This mechanism extends naturally to a language with procedures and output, where we show the soundness of the mechanism with respect to termination-insensitive noninterference.
Measuring channel capacity to distinguish undue influence (abstract only)
Authors: Newsome James , McCamant Stephen , Song Dawn
Published: December 2009

The channel capacity of a program is a quantitative measure of the amount of control that the inputs to a program have over its outputs. Because it corresponds to worst-case assumptions about the probability distribution over those inputs, it is particularly appropriate for security applications where the inputs are under the control of an adversary. We introduce a family of complementary techniques for measuring channel capacity automatically using a decision procedure (SAT or #SAT solver), which give either exact or narrow probabilistic bounds.

We then apply these techniques to the problem of analyzing false positives produced by dynamic taint analysis used to detect control-flow hijacking in commodity software. Dynamic taint analysis is based on the principle that an attacker should not be able to control values such as function pointers and return addresses, but it uses a simple binary approximation of control that commonly leads to both false positive and false negative errors. Based on channel capacity, we propose a more refined quantitative measure of influence, which can effectively distinguish between true attacks and false positives. We use a practical implementation of our influence measuring techniques, integrated with a dynamic taint analysis operating on x86 binaries, to classify tainting warnings produced by vulnerable network servers, such as those attacked by the Blaster and SQL Slammer worms. Influence measurement correctly distinguishes real attacks from tainting false positives, a task that would otherwise need to be done manually.
A language for information flow
Authors: Shinnar Avraham , Pistoia Marco , Banerjee Anindya
Published: December 2009

This paper presents λ
I
, a language for dynamic tracking of information flow across multiple, interdependent dimensions of information. Typical dimensions of interest are integrity and confidentiality. λ
I
supports arbitrary domain-specific policies that can be developed independently. ?I treats information-flow metadata as a first-class entity and tracks information flow on the metadata itself (integrity on integrity, integrity on confidentiality, etc.).

This paper also introduces IMPOLITE, a novel class of information-flow policies for λ
I
. Unlike many systems, which only allow for absolute-security relations, IMPOLITE can model more realistic security policies based on relative-security relations. IMPOLITE demonstrates how policies on interdependent dimensions of information can be simultaneously enforced within λ
I
's unified framework.
Confronting a Neglected Epidemic: Tobacco Cessation for Persons with Mental Illnesses and Substance Abuse Problems
Authors: Schroeder Steven A. , Morris Chad D.
Published: December 2009

Tobacco use exerts a huge toll on persons with mental illnesses and substance abuse disorders, accounting for 200,000 of the annual 443,000 annual tobacco-related deaths in the United States. Persons with chronic mental illness die 25 years earlier than the general population does, and smoking is the major contributor to that premature mortality. This population consumes 44% of all cigarettes, reflecting very high prevalence rates plus heavy smoking by users. The pattern reflects a combination of biological, psychosocial, cultural, and tobacco industry–related factors. Although provider and patient perspectives are changing, smoking has been a historically accepted part of behavioral health settings. Additional harm results from the economic burden imposed by purchasing cigarettes and enduring the stigma attached to smoking. Tailored treatment for this population involves standard cessation treatments including counseling, medications, and telephone quitlines. Further progress depends on clinician and patient education, expanded access to treatment, and the resolution of existing knowledge gaps.
Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non–Small Cell Lung Cancer
Authors: Hammerman Peter S. , Jänne Pasi A. , Johnson Bruce E.
Published: December 2009

Gefitinib and erlotinib are ATP competitive inhibitors of the epidermal growth factor receptor (EGFR) tyrosine kinase and are approved around the world for the treatment of patients with non-small cell lung cancer (NSCLC). Somatic mutations in the EGFR are found in 10 to 40% of patients with NSCLC. Patients with sensitizing somatic mutations of EGFR treated with gefitinib or erlotinib have an initial clinical response of 60 to 80%, approximately twice as high as the responses associated with the administration of conventional platinum-based chemotherapy. However, the efficacy of EGFR tyrosine kinase inhibitors (TKI) is limited by either primary (de novo) or acquired resistance after therapy and investigations to define the mechanisms of resistance are active areas of ongoing preclinical and clinical studies. Primary resistance is typically caused by other somatic mutations in genes such as KRAS, which also have an impact on the EGFR signaling pathway or by mutations in the EGFR gene that are not associated with sensitivity to EGFR-TKIs. Two established mechanisms of acquired resistance are caused by additional mutations in the EGFR gene acquired during the course of treatment that change the protein-coding sequence or by amplification of another oncogene signaling pathway driven by the MET oncogene. This review focuses on characterized mechanisms of resistance to the EGFR TKIs and efforts to overcome the problem of resistance aimed at improving the therapy of patients with NSCLC. (Clin Cancer Res 2009;15(24):7502–9)
Vascular Endothelial Growth Factor Receptor-1 Is Synthetic Lethal to Aberrant β-Catenin Activation in Colon Cancer
Authors: Naik Snehal , Dothager Robin S. , Marasa Jayne , Lewis Cory L. , Piwnica-Worms David
Published: December 2009

Purpose: The Wnt/β-catenin (β-cat) signaling cascade is a key regulator of development, and dysregulation of Wnt/β-cat contributes to selected cancers, such as colorectal, breast, and hepatocellular carcinoma, through abnormal activation of Wnt target genes. To identify novel modulators of the Wnt/β-cat pathway that may emerge as therapeutic targets, we did an unbiased high-throughput RNA interference screen.

Experimental Design: A synthetic oligonucleotide small interfering RNA library targeting 691 known and predicted human kinases was screened in Wnt3a-stimulated human cells in a live cell luciferase assay for modulation of Wnt/β-cat–dependent transcription. Follow-up studies of a selected high-confidence “hit” were conducted.

Results: A robust quartile-based statistical analysis and secondary screen yielded several kinases worthy of further investigation, including Cdc2L1, Lmtk3, Pank2, ErbB3, and, of note, vascular endothelial growth factor receptor (VEGFR)1/Flt1, a receptor tyrosine kinase (TK) with putative weak kinase activity conventionally believed to be a negative regulator of angiogenesis. A series of loss-of-function, genetic null, and VEGFR TK inhibitor assays further revealed that VEGFR1 is a positive regulator of Wnt signaling that functions in a glycogen synthase kinase-3β (GSK3β)–independent manner as a potential synthetic lethal target in Wnt/β-cat–addicted colon carcinoma cells.

Conclusions: This unanticipated non-endothelial link between VEGFR1 TK activity and Wnt/β-cat signaling may refine our understanding of aberrant Wnt signaling in colon carcinoma and points to new combinatorial therapeutics targeted to the tumor cell compartment, rather than angiogenesis, in the context of colon cancer. (Clin Cancer Res 2009;15(24):7529–37)