bluuebunny/crossref_metadata_2025 huggingface dataset:
Tectonic history of the central Humber Zone, western Newfoundland Appalachians: post-Taconian deformation in the Old Man's Pond area
Authors: Waldron John W. F. , Milne John V.
Published: June 2010

In the Humber Zone of the west Newfoundland Appalachians, the Middle Ordovician Taconian orogeny led to emplacement of the Humber Arm and other allochthons above a rift and shelf succession of late Precambrian to Early Ordovician age. Later deformation reversed this stacking in the Old Man's Pond area, where shelf sediments are thrust over the Old Man's Pond Group. East-vergent folds were subsequently developed in association with a regional, west-dipping cleavage that overprints the Taconian structures and intensifies eastward. Later, a major episode of shearing along normal-sense, northwest-dipping shear zones juxtaposed the Old Man's Pond Group against metamorphosed rift-related sediments and volcanics of the Hughes Lake Slice. This extensional episode may be related to intrusive events in adjacent central Newfoundland. The shear zones are overprinted by "cross folds," west-vergent folds, crenulation cleavage, and thrusts. These late structures are inferred to be related to westward transport of the rift–shelf succession and the Grenville-age basement rocks of the Long Range massif above a detachment surface, probably in Devonian time. The structural history is difficult to reconcile with a single, Devonian, "Acadian" orogeny, but is consistent with published isotopic data from central Newfoundland that suggest continued protracted tectonic activity in the Humber Zone in Silurian time.
Stratigraphy and paleolimnologic record of lower Holocene sediments in northern Lake Huron and Georgian Bay
Authors: Rea David K. , Moore Jr. Theodore C. , Lewis C. F. Michael , Mayer Larry A. , Dettman David L. , Smith Alison J. , Dobson David M.
Published: June 2010

Seismic reflection profiling and piston coring identified seismic reflectors in northern Lake Huron and Georgian Bay linked with unconformities caused by at least six reductions in lake level. In ascending stratigraphic order, these lowstands occurred at about 11 200 BP, associated with the Kirkfield outlet from early Lake Algonquin; 10 200 – 9900 BP, associated with the post-Algonquin lake level fall; 9800 – 9050 BP, the most extreme lowstand, associated with the main Stanley – Hough draw down; and 7800 – 7450 BP. The concomitant highstands are Lake Algonquin, from about 11 200 – 10 200 BP; early Lake Mattawa, between 9600 and 9350 BP; the main Mattawa phase, 9050–7800 BP; and the Nipissing highstand, at about 4700 BP. Isotopic and paleoecological data show that all of the lowstands are characterized by cold, dilute, and isotopically very light (< −20‰) waters from the melting Laurentian ice cap. Highstands, on the other hand, are characterized by higher dissolved solid concentrations and a much smaller meltwater component. Oxygen isotope values of the waters in these lakes were −15 to −17‰ in Lake Algonquin, −13 to −14‰ for the early and middle Mattawa stages, −9 to −8‰ for the main Mattawa stage, and −7‰ for modern waters. This association of lowstands and not highstands with isotopically light waters is a new contribution to early Holocene hydrology of the Great Lakes. The Younger Dryas cool episode is coeval with the Lake Algonquin highstand and a younger cool episode is generally coeval with the Mattawa highstand. This supports the hypothesis of C.F.M. Lewis and T.W. Anderson that these large cold lakes were responsible for regional cooling during the early Holocene.
40Ar/39Ar dating of metamorphic and igneous rocks of the Liscomb Complex, Meguma Terrane, southern Nova Scotia, Canada
Authors: Kontak D. J. , Reynolds P. H.
Published: June 2010

Recent geological mapping in the Meguma Terrane of southern Nova Scotia has revealed the presence of previously unrecognized high-grade gneisses and gabbroic rocks that form, along with previously recognized granitic rocks, the Liscomb Complex. Field relationships indicate emplacement of the suites, in the sequence gneisses, gabbros, and granites, after the ca. 400 Ma Acadian deformation of the Meguma Group metasedimentary rocks. 40Ar/39Ar dating of amphibole and mica phases from these suites indicates (1) an amphibole inverse isochron age of 375 ± 3 Ma for the gneisses, and amphibole plateau ages of 371 ± 4 and 372 ± 5 Ma for the gabbros; (2) muscovite plateau ages of 367 ± 3 Ma for the gneisses, and 369 ± 3 to 373 ± 4 Ma for the granites; and (3) variably discordant biotite age spectra with integrated ages sometimes greater than the amphibole and muscovite plateau ages (371 – 383 Ma (n = 5) gneisses; 373–385 Ma (n = 3) gabbros; 367 and 368 Ma in granites). The spectral discordance in the biotites is attributed to irradiation-induced recoil in the presence of sub-microscopic chlorite, whereas the high integrated ages reflect excess argon.Collectively, the age data indicate rapid cooling of the Liscomb Complex through the argon retention temperatures of amphibole (approx. 500 °C) and micas (approx. 350–300 °C), consistent with previous 40Ar/39Ar dating of amphibole and micas in this area. This cooling history is attributed to rapid uplift and exhumation of the area postemplacement of the units because of its close proximity (i.e., along its northern boundary) to the Cobequid – Chedabucto Fault System.
Timing constraints on deformation history of the Sudbury Impact Structure
Authors: Wu Jianjun , Milkereit Bernd , Boerner David
Published: June 2010

Herein, we present new high-resolution seismic images of the Sudbury Impact Structure, acquired across the Sudbury Igneous Complex and its environs, which provide evidence for the relative timing of the deformation events that reshaped the initial Sudbury Structure. The seismic images show that the lower unit of the Sudbury basinal fill sediments, the Onwatin argillite, is penetrated by a set of blind, imbricated thrusts, whereas the overlying Chelmsford turbidites are unaffected by faulting. We interpret this observation to mean that the deposition of the Chelmsford sediments postdates the latest major deformation of the Sudbury Structure, suggesting that the uniform paleocurrent trends observed in the Chelmsford turbidites are not related to the initial shape of the Sudbury Structure.
A xiphisternal from the Dinosaur Park Formation (Campanian, Upper Cretaceous) of Alberta, Canada
Authors: Godfrey Stephen J. , Currie Philip J.
Published: June 2010

Xiphisternal elements of dinosaurs are only rarely recovered, probably because they seldom ossified and those that did were fragile and easily destroyed. An isolated but relatively complete, right xiphisternal element was collected from the Dinosaur Park Formation of Dinosaur Provincial Park, Alberta. It apparently contacted the left xiphisternal, the sternum, and at least three costal cartilages. Similar in overall morphology to xiphisternals of Edmontonia, Nodosaurus, and Panoplosaurus, it can be referred to the ankylosaur family Nodosauridae.
Contrasting tectono-stratigraphy and structure in the Coast Belt near Chilko Lake, British Columbia: unrelated terranes or an arc – back-arc transect?
Authors: Umhoefer Paul J. , Rusmore Margaret E. , Woodsworth G. J.
Published: June 2010

Stratigraphy and structural styles vary greatly in two areas of the Coast Belt near Chilko Lake (Chilcotin Ranges in the east and Coast Mountains in the west). No definite continuity between the two belts has been established in the pre-mid-Cretaceous geology, but this area may be a long-lived, episodic magmatic arc and nearby arc-related basin. The stratigraphic contrasts may reflect inherent differences between an arc and related basinal sequence. Triassic volcanic-arc sequences are part of the Stikine (western belt) and Cadwallader (eastern belt) terranes, which may be part of the same arc. The Jurassic is represented by one dated pluton in the west compared with almost continuous deposition of volcanogenic clastic rocks in the east. Lower Cretaceous sequences in the west and east may represent a volcanic arc and back-arc basin. The Taylor Creek Group (Albian) is the first definitive link between the two belts and represents an arc and intra-arc or back-arc basin. The structural evolution of the two belts also differs significantly. The early Late Cretaceous Eastern Waddington thrust belt comprises all major structures in the west, but only has minor expression in the east. Most of the structures in the east are part of the latest Cretaceous(?) to early Tertiary dextral-strike-slip, Yalakom fault system. These differences were most likely caused by the Late Cretaceous change from nearly orthogonal subduction to a dextral-oblique convergent margin.
Ten-year growth results of nitrogen source and interprovincial experiments on jack pine
Authors: Weetman G. F. , Fournier R. M.
Published: June 2010

Sample plots in a 45-year-old jack pine (Pinusbanksiana Lamb.) stand in Quebec were fertilized with urea, ammonium nitrate, and calcium nitrate in single applications of 112 or 448 kg N/ha. There were no significant differences in periodic volume response owing to the form of N added; applications of 112 kg N/ha gave temporary increases in stand growth which lasted 4–5 years, while applications of 448 kg N/ha produced responses lasting 7–8 years. In an experiment of the standardized interprovincial series no significant differences in periodic volume response were found although there was an indication of increased response to the addition of P with N. Fertilizer efficiency was examined for single and repeated applications on the site. The most efficient fertilizer use was with repeated light applications of 56 kg N/ha, requiring 8 kg N for every cubic metre per hectare produced.
Relationship between spacing and nitrogen fertilization of seedlings in the nursery, seedling mineral nutrition, and outplanting performance
Authors: Driessche R. van den
Published: June 2010

Three nitrogen (N) levels and six seedling spacings were applied factorially in a randomized block design, of four replications, to coastal and interior varieties of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), Sitka spruce (Piceasitchensis (Bong.) Carr), and lodgepole pine (Pinuscontorta Dougl.) in the nursery. After growing for 2 years in the nursery, seedling dimensions, dry weights, and needle N, phosphorus (P), and potassium (K) concentrations were determined. At the same time, samples of 400 trees per treatment were planted into the forest using the nursery design. Three years after outplanting, survival and height measurements were obtained for all species and, in addition, dry weights and nutrient concentrations for the coastal Douglas-fir. Both an increase in N fertilizer and wider spacing increased 2-year-old (2–0) seedling needle percent N, except in lodgepole pine. Wider spacing also increased percent P in interior Douglas-fir and percent K in lodgepole pine. Within the highest N fertilizer level the amount of variation in needle percent N accounted for by spacing was 75% in coastal Douglas-fir, 78% in interior Douglas-fir, and 92% in Sitka spruce. Needle percent N in 2–0 coastal Douglas-fir and Sitka spruce was positively correlated with survival (r2 = 0.24 and 0.35, respectively), total height (r2 = 0.48 and 0.61, respectively), and current height growth (r2 = 0.31 and 0.51, respectively) after 3 years in the forest. The relationships of spacing to 2–0 seedling percent N, and of 2–0 seedling percent N to outplanting performance indicated that, at least for Douglas-fir and Sitka spruce, spacing influenced outplanting performance through its effect on N nutrition. During 3 years in the forest, coastal Douglas-fir trees had maintained closely similar relative growth rates (RGR) in all treatments. Consequently, relative differences in 2–0 seedling dry weight between treatments of about threefold between 0.6- and 12-cm spacing and twofold between 60 and 235 kg N/ha fertilizer levels, had been maintained. After 3 years in the forest there were no differences in nutrient concentrations between nursery N treatments, indicating that reserves available at lifting had been dissipated, but nutrient concentrations tended to decrease with wider spacing. This suggested some unidentified wide spacing effect was promoting growth and causing nutrient dilution in the tissue.
Forest growth and the effects of energy production: a method for detecting trends in the growth potential of trees
Authors: Hari P. , Arovaara H. , Raunemaa T. , Hautojärvi A.
Published: June 2010

An increase in the CO2 content of the atmosphere and in the acidity of rain has been detected in large regions of the northern hemisphere. Both these factors can affect the productivity of trees. A three-component model has been employed for the detection of possible trends in the growth potential of trees. The components are (i) the growth intensity associated with tree age, (ii) the effect of weather, and (iii) the effect of possible long-term trends on the radial growth. The model was tested with a limited set of data from conservation stands in southern and central Finland. Preliminary results indicate that an increase in tree growth rate since the beginning of the 20th century has occurred.
Stimulation of early height growth in longleaf pine with growth regulators
Authors: Hare Robert C.
Published: June 2010

Longleaf pine (Pinuspalustris Mill.), although it has many excellent qualities, is not extensively planted because of its extended seedling "grass stage" accompanied by poor field survival. Treatments with cytokininlike substances in spring and early summer stimulated seedling height growth, and this effect was enhanced by gibberellic acid (GA3) and DPX 3778, an experimental triazinone derivative that is synergistic with gibberellins. The synthetic cytokinin benzyladenine and other active purine derivatives, although potent, tended to cause bud proliferation and death. A seaweed extract with cytokinin activity, Cytex, proved effective without the deleterious side effects. A promising technique is thus to apply combination sprays of Cytex, GA3, and DPX 3778 in the nursery to stimulate height growth during the 1st year in the field.
Improving germination of hop-hornbeam seeds
Authors: Pitel J. A. , Wang B. S. P. , Cheliak W. M.
Published: June 2010

The effects of stratification, clipping, sulfuric acid soaking, and pericarp removal on the germination of hop-hornbeam (Ostryavirginiana [Mill.] K. Koch) seeds were investigated. Untreated seeds failed to germinate. Removing the pericarp produced 34–37% germination. Gibberellic acid (GA3) improved germination of intact seeds, but was most effective for seeds with pericarps removed, resulting in 76–80% germination. Although stratification of intact seeds for 3 months produced 15% germination, a combination of pericarp removal, GA3 treatment, and stratification was best, resulting in 81% germination. For seed testing, the pericarps should be removed and seeds treated with 500 mg/L GA3 for 24 h at 20 °C. Germination at 20 °C with continuous light appears to be a good test condition.
Clonal and sexual variation in initial graft take of Juniperusvirginiana L.
Authors: Haverbeke David F. Van
Published: June 2010

Graftings of 44 Juniperusvirginiana L. clones revealed significant differences in initial graft take among clones and between ovulate and staminate clones. Consistent year to year successes of individual clones indicate the presence of clonal variability in J. virginiana.
IMPROVEMENT AND ANALYSIS OF A PSEUDO-RANDOM BIT GENERATOR BY MEANS OF CELLULAR AUTOMATA
Authors: MURGUÍA J. S. , CARLOS M. MEJÍA , ROSU H. C. , FLORES-ERAÑA G.
Published: June 2010

In this paper, we implement a revised pseudo-random bit generator based on a rule-90 cellular automaton. For this purpose, we introduce a sequence matrix HNwith the aim of calculating the pseudo-random sequences of N bits employing the algorithm related to the automaton backward evolution. In addition, a multifractal structure of the matrix HNis revealed and quantified according to the multifractal formalism. The latter analysis could help to disentangle what kind of automaton rule is used in the randomization process and therefore it could be useful in cryptanalysis. Moreover, the conditions are found under which this pseudo-random generator passes all the statistical tests provided by the National Institute of Standards and Technology (NIST).
OPTIMAL DIRECTED CURRENT OF A BROWNIAN MOTOR UNDER A NON-GAUSSIAN NOISE GENERATED BY A MULTIPLICATIVE PROCESS
Authors: DUARTE J. R. R. , LYRA M. L.
Published: June 2010

Unidirectional motion is achieved when a particle, moving under the influence of an underlying noise source, is subjected to a ratchet asymmetric periodic potential. Here, we investigate how deviations from the Gaussian nature of the noise distribution function impacts the average particle's current. The input noise is considered to be produced by a Langevin process including both multiplicative and additive random noise sources. The resulting input random signal has a power-law amplitude distribution and a finite correlation time. These features are controlled by the average of the multiplicative noise. We show that the average particle's velocity depends non-monotonically on the degree of non-Gaussianity of the input noise. It exhibits a maximum at an intermediate value of the effective power-law exponent that characterizes the asymptotic decay of the noise probability distribution function.
UNSTRUCTURED LATTICE BOLTZMANN METHOD FOR HEMODYNAMIC FLOWS WITH SHEAR-DEPENDENT VISCOSITY
Authors: JANELA J. , SEQUEIRA A. , PONTRELLI G. , SUCCI S. , UBERTINI S.
Published: June 2010

The lattice Boltzmann formulation on unstructured grids (ULBE) is compared against semi-analytical solutions of non-Newtonian flows in straight channels, as well as with finite-element simulations in stenosed geometries. In all cases, satisfactory agreement is found, lending further credit to the ULBE method as a potentially useful method for the numerical simulation of small-scale hemodynamic flows, such as blood flow in capillaries and arterioles.
SIMILARITY-BASED CLASSIFICATION IN PARTIALLY LABELED NETWORKS
Authors: ZHANG QIAN-MING , SHANG MING-SHENG , LÜ LINYUAN
Published: June 2010

Two main difficulties in the problem of classification in partially labeled networks are the sparsity of the known labeled nodes and inconsistency of label information. To address these two difficulties, we propose a similarity-based method, where the basic assumption is that two nodes are more likely to be categorized into the same class if they are more similar. In this paper, we introduce ten similarity indices defined based on the network structure. Empirical results on the co-purchase network of political books show that the similarity-based method can, to some extent, overcome these two difficulties and give higher accurate classification than the relational neighbors method, especially when the labeled nodes are sparse. Furthermore, we find that when the information of known labeled nodes is sufficient, the indices considering only local information can perform as good as those global indices while having much lower computational complexity.
EFFECT OF LEADER'S STRATEGY ON OPINION FORMATION IN NETWORKED SOCIETIES WITH LOCAL INTERACTIONS
Authors: SOBKOWICZ PAWEL
Published: June 2010

The work investigates the influence of leader on opinion formation in artificial networked societies. The strength of the social influence is assumed to be dictated by distance from one agent to another, as well as individual strengths of the agents. The leader is assumed to have much greater resources, which allows him to tune the way he influences the other agents. We study various strategies of using these resources to optimize the conditions needed to "convince" the whole society to leader's opinion. The flexibility of the model allows it to be used in studies of political, social and marketing activities and opinion formation.
ANOMALOUS HALL EFFECT IN PARAMAGNETIC 2DEG WITH LINEAR AND CUBIC DRESSELHAUS SPIN–ORBIT COUPLING
Authors: ZHU HUANGJUN
Published: June 2010

We study the anomalous Hall effect in paramagnetic two-dimensional electron gas (2DEG) with both linear and cubic Dresselhaus spin–orbit coupling by means of Berry connection and Berry curvature. The effect of tuning the Fermi level and of tuning the cubic coupling coefficient on the anomalous Hall conductivity have been investigated semiclassically. Our results show that a sign reversal in the anomalous Hall conductivity may appear if the cubic Dresselhaus coefficient is very large and the Fermi surface is high enough, so the cubic Dresselhaus spin–orbit coupling term cannot be neglected in this case.
SCHEME FOR ENTANGLEMENT CONCENTRATION OF UNKNOWN W CLASS STATES IN BAD CAVITIES
Authors: ZHANG LI-HUA , YANG MING , WANG QI-SHEN , CAO ZHUO-LIANG
Published: June 2010

In this paper, we propose an entanglement concentration protocol for unknown tripartite W class states via the detection of photons which are leaked out from the cavities. In our scheme, the atom-cavity coupling strength is smaller than the cavity decay rate. Hence, the requirement on the quality factor of the cavities is greatly relaxed. The scheme is for nonpost-selection results and the fidelity of the scheme is not affected by the detection inefficiency and atomic decay. All the processes are within the current technologies.
MEASUREMENTS OF THE RELATIVE OSCILLATOR STRENGTHS OF THE PRINCIPAL SERIES OF COPPER
Authors: AHMAD ISHAQ , BAIG M. A. , RASHID A.
Published: June 2010

New measurements of the relative oscillator strengths of copper for the 3 d 104 s 2 S 1/2→3 d 10n p 2 P 1/2, (7 ≤ n ≤ 13), and 2 P 3/2(7 ≤ n ≤ 23) series are reported. The data were acquired using the magneto-optical rotation spectroscopic technique, utilizing the linearly polarized light emitted by the 2.5 GeV electron accelerator, a 7 Tesla superconducting magnet, and a 3-meter high dispersion spectrograph with photographic detection. A quantum defect plot of the density of oscillator strengths of the discrete transitions is also presented.
MECHANISM OF QUENCHING OF SUPERCONDUCTIVITY IN THE YBa2Cu3O7-δ SYSTEM ON SUBSTITUTION OF Zn FOR Cu
Authors: GARG K. B. , GAUR S. K. , SINGHAL R. K. , PAL P. , SEKHAR B. R. , NORDBLAD P. , CARLSON S.
Published: June 2010

Substituting Zn for Cu is known to rapidly quench superconductivity in the doped perovskites but the mechanism behind it is still not clearly understood. Single phase YBa 2( Cu 1-x Zn x)3 O 7-δ (x = 0.0 to 0.06) samples were synthesized and characterized using XRD, wet titration, resistivity, and ac susceptibility. Angle-integrated Valence Band Photoemission and Zn K-edge XAFS results clearly show that their oxygen stoichiometry (δ) changes on Zn substitution, thereby adversely affecting the density of free charge carriers and hence the normal state resistivity and the Tc. However, the observed changes in the two happen to be too large to be accounted for solely on the basis of changes in the oxygen stoichiometry δ. We find that the Zn cation acts as a strong "impurity" scattering centre in the YBCO lattice and causes local lattice distortion (LLD). It consequently induces local magnetic moment, seen in our dc susceptibility measurements. It is thus a composite of (Δδ), LLD and possibly also magnetic pair-breaking that is responsible for the rapid quenching of the superconductivity observed with Zn doping in this system.
MODULATIONAL INSTABILITY AND EXACT SOLITON AND PERIODIC SOLUTIONS FOR TWO WEAKLY COUPLED EFFECTIVELY 1D CONDENSATES TRAPPED IN A DOUBLE-WELL POTENTIAL
Authors: KENGNE E. , VAILLANCOURT R. , MALOMED B. A.
Published: June 2010

The modulational instability of the coupled Gross–Pitaevskii equation (alias nonlinear Schrödinger equation), which describes two Bose–Einstein condensates trapped in an asymmetric double-well potential, is investigated. The nonlinear dispersion relation that relates the frequency and wave number of the modulating perturbations is found and its analysis shows several possibilities for the modulational stability region. Exact soliton and periodic solutions are constructed via elliptic ordinary differential equations.
CHAOS ANTI-SYNCHRONIZATION BETWEEN DIFFERENT HYPERCHAOTIC SYSTEMS WITH UNCERTAINTY
Authors: ZHENG QIANG , ZHANG XIAOPING , REN ZHONGZHOU
Published: June 2010

Anti-synchronization between different hyperchaotic systems is presented using the Chen and a new system. When the parameters of two systems are known, one can apply active synchronization method. When the parameters are unknown or uncertain, one can apply adaptive synchronization method. The simulation results verify the effectiveness of the proposed two schemes.
FIRST-PRINCIPLES STUDIES ON THE ELECTRONIC STRUCTURE OF BaCuSi2O6
Authors: JEONG T.
Published: June 2010

The electronic properties of BaCuSi 2 O 6 are studied by band structure calculation based on the density functional theory within local density approximation. We find that the electronic structure and properties are dominated by the layered character of the crystal structure arising from the in plane Cu 3d and O 2p electron interactions.
OPEN VESICLES WITH TWO EDGES
Authors: ZHOU XIAO-HUA , ZHANG XIAO-JUN , LIU YUAN-SHENG , QU XUE-MIN
Published: June 2010

Following the previous theoretical study on the open lipid membranes with edges by Tu and Ou-Yang [Phys. Rev. E68, 061915 (2003)], we show that the discocyte solution can give us several interesting open vesicles with two edges and the central singularity of this solution can be avoided in the meantime.
MAP BASED MODELS IN NEURODYNAMICS
Authors: COURBAGE M. , NEKORKIN V. I.
Published: June 2010

This tutorial reviews a new important class of mathematical phenomenological models of neural activity generated by iterative dynamical systems: the so-called map-based systems. We focus on 1-D and 2-D maps for the replication of many features of the neural activity of a single neuron. It was shown that such systems can reproduce the basic activity modes such as spiking, bursting, chaotic spiking-bursting, subthreshold oscillations, tonic and phasic spiking, normal excitability, etc. of the real biological neurons. We emphasize on the representation of chaotic spiking-bursting oscillations by chaotic attractors of 2-D models. We also explain the dynamical mechanism of formation of such attractors and transition from one mode to another. We briefly present some synchronization mehanisms of chaotic spiking-bursting activity for two coupled neurons described by 1-D maps.
RECURRENCE PLOTS FOR SYMBOLIC SEQUENCES
Authors: FAURE PHILIPPE , LESNE ANNICK
Published: June 2010

This paper introduces an extension of recurrence analysis to symbolic sequences. Heuristic arguments based on Shannon–McMillan–Breiman theorem suggest several relations between the statistical features of "symbolic" recurrence plots and the entropy per unit time of the dynamics; their practical efficiency for experimental sequences of finite length is checked numerically on two paradigmatic models, namely discretized logistic map trajectories and Markov chains, and also on experimental behavioral sequences. Specific advantages of RP analysis are presented, among which is the detection of nonstationary features.
EFFECT OF STEP SIZE ON BIFURCATIONS AND CHAOS OF A MAP-BASED BVP OSCILLATOR
Authors: CAO HONGJUN , WANG CAIXIA , SANJUÁN MIGUEL A. F.
Published: June 2010

The continuous Bonhoeffer–van der Pol (BVP for short) oscillator is transformed into a map-based BVP model by using the forward Euler scheme. At first, the bifurcations and chaos of the map-based BVP model are investigated when the step size varies as a bifurcation parameter. By using the fast-slow decomposition technique, a two-parameter bifurcation diagram is obtained to give insight into the effect of the step size on bifurcations and chaos of the map-based BVP model. The investigation shows that the period-doubling bifurcation is dependent on the step size, while the saddle-node bifurcation is independent of the step size. Second, when the fast–slow decomposition technique cannot be used, we rigorously prove that in the map-based BVP model there exists chaos in the sense of Marotto when the discrete step size varies as a bifurcation parameter. These results show that the discrete step sizes play a vital role between the continuous-time dynamical system and the corresponding discrete dynamical system. Much attention should be paid on the step size when a map-based neuron model is used as an alternative to a continuous neuron model.
Two-query PCP with subconstant error
Authors: Moshkovitz Dana , Raz Ran
Published: June 2010

We show that the NP-Complete language 3Sat has a PCP verifier that makes two queries to a proof of almost-linear size and achieves subconstant probability of error ε=
o
(1). The verifier performs only projection tests, meaning that the answer to the first query determines at most one accepting answer to the second query. The number of bits representing a symbol in the proof depends only on the error ε. Previously, by the parallel repetition theorem, there were PCP Theorems with two-query projection tests, but only (arbitrarily small)
constant
error and
polynomial
size. There were also PCP Theorems with
subconstant
error and
almost-linear
size, but a constant number of queries that is
larger
than 2.

As a corollary, we obtain a host of new results. In particular, our theorem improves many of the hardness of approximation results that are proved using the parallel repetition theorem. A partial list includes the following:

(1) 3Sat cannot be efficiently approximated to within a factor of 7/8+
o
(1), unless P=NP. This holds even under almost-linear reductions. Previously, the best known NP-hardness factor was 7/8+ε for any constant ε>0, under polynomial reductions (Håstad).

(2) 3Lin cannot be efficiently approximated to within a factor of 1/2+
o
(1), unless P=NP. This holds even under almost-linear reductions. Previously, the best known NP-hardness factor was 1/2+ε for any constant ε>0, under polynomial reductions (Håstad).

(3) A PCP Theorem with amortized query complexity 1 +
o
(1) and amortized free bit complexity
o
(1). Previously, the best-known amortized query complexity and free bit complexity were 1+ε and ε, respectively, for any constant ε>0 (Samorodnitsky and Trevisan).

One of the new ideas that we use is a new technique for doing the
composition
step in the (classical) proof of the PCP Theorem, without increasing the number of queries to the proof. We formalize this as a composition of new objects that we call
Locally Decode/Reject Codes
(LDRC). The notion of LDRC was implicit in several previous works, and we make it explicit in this work. We believe that the formulation of LDRCs and their construction are of independent interest.
Reconciling description logics and rules
Authors: Motik Boris , Rosati Riccardo
Published: June 2010

Description logics (DLs) and rules are formalisms that emphasize different aspects of knowledge representation: whereas DLs are focused on specifying and reasoning about conceptual knowledge, rules are focused on nonmonotonic inference. Many applications, however, require features of both DLs and rules. Developing a formalism that integrates DLs and rules would be a natural outcome of a large body of research in knowledge representation and reasoning of the last two decades; however, achieving this goal is very challenging and the approaches proposed thus far have not fully reached it. In this paper, we present a hybrid formalism of

MKNF
+

knowledge bases
, which integrates DLs and rules in a coherent semantic framework. Achieving seamless integration is nontrivial, since DLs use an open-world assumption, while the rules are based on a closed-world assumption. We overcome this discrepancy by basing the semantics of our formalism on the logic of minimal knowledge and negation as failure (MKNF) by Lifschitz. We present several algorithms for reasoning with MKNF
+
knowledge bases, each suitable to different kinds of rules, and establish tight complexity bounds.
In the Virtual Extension
Authors: CACM Staff
Published: June 2010

Communications'
Virtual Extension brings more quality articles to ACM members. These articles are now available in the ACM Digital Library.
Sharing computational perspectives
Authors: Lindley David
Published: June 2010

Computer scientists are now making intellectual contributions to a wide range of other disciplines, including evolutionary theory, physics, and economics.
Censored!
Authors: Greengard Samuel
Published: June 2010

Countries use Internet censorship to dominate the political dialogue, but also to create favorable conditions for government-controlled businesses.
Committed to success
Authors: Anthes Gary
Published: June 2010

Charles P. Thacker talks about the importance of simplicity, reusable tools, thinking broadly, and his practice of Tom Sawyering.
Should the Google book settlement be approved?
Authors: Samuelson Pamela
Published: June 2010

Considering the precedent that could be established by approval of the controversial Google book settlement.
Cultivating cultural diversity in information technology
Authors: Taylor Valerie E.
Published: June 2010

Introducing CMD-IT, a new center focused on synergistic activities related to ethnic minorities and people with disabilities.
You're doing it wrong
Authors: Kamp Poul-Henning
Published: June 2010

Think you've mastered the art of server performance? Think again.
Phase change memory architecture and the quest for scalability
Authors: Lee Benjamin C. , Ipek Engin , Mutlu Onur , Burger Doug
Published: June 2010

Memory scaling is in jeopardy as charge storage and sensing mechanisms become less reliable for prevalent memory technologies, such as dynamic random access memory (DRAM). In contrast, phase change memory (PCM) relies on programmable resistances, as well as scalable current and thermal mechanisms. To deploy PCM as a DRAM alternative and to exploit its scalability, PCM must be architected to address relatively long latencies, high energy writes, and finite endurance.

We propose architectural enhancements that address these limitations and make PCM competitive with DRAM. A baseline PCM system is 1.6× slower and requires 2.2× more energy than a DRAM system. Buffer reorganizations reduce this delay and energy gap to 1.2× and 1.0×, using narrow rows to mitigate write energy as well as multiple rows to improve locality and write coalescing. Partial writes mitigate limited memory endurance to provide more than 10 years of lifetime. Process scaling will further reduce PCM energy costs and improve endurance.
Protective effects ofLactobacillus paracaseiF19 in a rat model of oxidative and metabolic hepatic injury
Authors: Nardone Gerardo , Compare Debora , Liguori Eleonora , Di Mauro Valentina , Rocco Alba , Barone Michele , Napoli Anna , Lapi Dominga , Iovene Maria Rosaria , Colantuoni Antonio
Published: June 2010

The liver is susceptible to such oxidative and metabolic stresses as ischemia-reperfusion (I/R) and fatty acid accumulation. Probiotics are viable microorganisms that restore the gut microbiota and exert a beneficial effect on the liver by inhibiting bacterial enzymes, stimulating immunity, and protecting intestinal permeability. We evaluated Lactobacillus paracasei F19 (LP-F19), for its potential protective effect, in an experimental model of I/R (30 min ischemia and 60 min reperfusion) in rats fed a standard diet or a steatogen [methionine/choline-deficient (MCD)] diet. Both groups consisted of 7 sham-operated rats, 10 rats that underwent I/R, and 10 that underwent I/R plus 8 wk of probiotic dietary supplementation. In rats fed a standard diet, I/R induced a decrease in sinusoid perfusion ( P < 0.001), severe liver inflammation, and necrosis besides an increase of tissue levels of malondialdehyde ( P < 0.001), tumor necrosis factor-α ( P < 0.001), interleukin (IL)-1β ( P < 0.001), and IL-6 ( P < 0.001) and of serum levels of transaminase ( P < 0.001) and lipopolysaccharides ( P < 0.001) vs. sham-operated rats. I/R also induced a decrease in Bacterioides , Bifidobacterium , and Lactobacillus s pps ( P < 0.01, P < 0.001, and P < 0.001, respectively) and an increase in Enterococcus and Enterobacteriaceae ( P < 0.01 and P < 0.001, respectively) on intestinal mucosa. The severity of liver and gut microbiota alterations induced by I/R was even greater in rats with liver inflammation and steatosis, i.e., MCD-fed animals. LP-F19 supplementation significantly reduced the harmful effects of I/R on the liver and on gut microbiota in both groups of rats, although the effect was slightly less in MCD-fed animals. In conclusion, LP-F19 supplementation, by restoring gut microbiota, attenuated I/R-related liver injury, particularly in the absence of steatosis.
Inactivation of hepatocyte nuclear factor-4α mediates alcohol-induced downregulation of intestinal tight junction proteins
Authors: Zhong Wei , Zhao Yantao , McClain Craig J. , Kang Y. James , Zhou Zhanxiang
Published: June 2010

Chronic alcohol exposure has been shown to increase the gut permeability in the distal intestine, in part, through induction of zinc deficiency. The present study evaluated the molecular mechanisms whereby zinc deficiency mediates alcohol-induced intestinal barrier dysfunction. Examination of zinc finger transcription factors in the gastrointestinal tract of mice revealed a prominent distribution of hepatocyte nuclear factor-4α (HNF-4α). HNF-4α exclusively localizes in the epithelial nuclei and exhibited an increased abundance in mRNA and protein levels in the distal intestine. Chronic alcohol exposure to mice repressed the HNF-4α gene expression in the ileum and reduced the protein level and DNA binding activity of HNF-4α in all of the intestinal segments with the most remarkable changes in the ileum. Chronic alcohol exposure also decreased the mRNA levels of tight junction proteins, particularly in the ileum. Caco-2 cell culture studies were conducted to determine the role of HNF-4α in regulation of the epithelial tight junction and barrier function. Knockdown of HNF-4α in Caco-2 cells decreased the mRNA and protein levels of tight junction proteins in association with disruption of the epithelial barrier. Alcohol treatment inactivated HNF-4α, which was prevented by N-acetyl-cysteine or zinc. The link between zinc and HNF-4α function was confirmed by zinc deprivation, which inhibited HNF-4α DNA binding activity. These results indicate that inactivation of HNF-4α due to oxidative stress and zinc deficiency is likely a novel mechanism contributing to the deleterious effects of alcohol on the tight junctions and the intestinal barrier function.
Rab10 associates with primary cilia and the exocyst complex in renal epithelial cells
Authors: Babbey Clifford M. , Bacallao Robert L. , Dunn Kenneth W.
Published: June 2010

Rab10, a mammalian homolog of the yeast Sec4p protein, has previously been associated with endocytic recycling and biosynthetic membrane transport in cultured epithelia and with Glut4 translocation in adipocytes. Here, we report that Rab10 associates with primary cilia in renal epithelia in culture and in vivo. In addition, we find that Rab10 also colocalizes with exocyst proteins at the base of nascent cilia, and physically interacts with the exocyst complex, as detected with anti-Sec8 antibodies. These data suggest that membrane transport to the primary cilum may be mediated by interactions between Rab10 and an exocyst complex located at the cilium base.
Chloroform extract of hog barn dust modulates skeletal muscle ryanodine receptor calcium-release channel (RyR1)
Authors: Tian Chengju , Shao Chun Hong , Fenster Danielle S. , Mixan Mark , Romberger Debra J. , Toews Myron L. , Bidasee Keshore R.
Published: June 2010

Skeletal muscle weakness is a reported ailment in individuals working in commercial hog confinement facilities. To date, specific mechanisms responsible for this symptom remain undefined. The purpose of this study was to assess whether hog barn dust (HBD) contains components that are capable of binding to and modulating the activity of type 1 ryanodine receptor Ca2+-release channel (RyR1), a key regulator of skeletal muscle function. HBD collected from confinement facilities in Nebraska were extracted with chloroform, filtered, and rotary evaporated to dryness. Residues were resuspended in hexane-chloroform (20:1) and precipitates, referred to as HBDorg, were air-dried and studied further. In competition assays, HBDorgdose-dependently displaced [3H]ryanodine from binding sites on RyR1 with an IC50of 1.5 ± 0.1 μg/ml ( Ki= 0.4 ± 0.0 μg/ml). In single-channel assays using RyR1 reconstituted into a lipid bilayer, HBDorgexhibited three distinct dose-dependent effects: first it increased the open probability of RyR1 by increasing its gating frequency and dwell time in the open state, then it induced a state of reduced conductance (55% of maximum) that was more likely to occur and persist at positive holding potentials, and finally it irreversibly closed RyR1. In differentiated C2C12myotubes, addition of HBD triggered a rise in intracellular Ca2+that was blocked by pretreatment with ryanodine. Since persistent activation and/or closure of RyR1 results in skeletal muscle weakness, these new data suggest that HBD is responsible, at least in part, for the muscle ailment reported by hog confinement workers.
Muscle characteristics and altered myofascial force transmission in tenascin-X-deficient mice, a mouse model of Ehlers-Danlos syndrome
Authors: Huijing Peter A. , Voermans Nicol C. , Baan Guus C. , Busé Tinelies E. , van Engelen Baziel G. M. , de Haan Arnold
Published: June 2010

The Ehlers-Danlos syndrome is a group of inherited connective tissue disorders caused by defects in collagens or tenascin-X (TNX). Muscle involvement can be expected based on interactions between muscle and extracellular matrix molecules; however, muscle function has not yet been investigated quantitatively. This study aims to investigate effects of TNX deficiency on muscular characteristics in TNX knockout (KO) mice, a mouse model of Ehlers-Danlos syndrome. At lower muscle lengths, maximally dissected medial gastrocnemius muscle-tendon complex of TNX KO mice showed lower active force, lower maximal rate of relaxation, and longer time delay between first stimulation pulse and initial force rise, supporting the hypothesis that relatively more slack needs to be taken up, as well as more elastic length changes occurring. In addition, study of the minimally dissected lower leg muscles shows that TNX deficiency strongly affects the mechanical interaction between antagonistic, as well as synergistic, muscles, which is consistent with the concept of altered myofascial force transmission due to increased compliance of myofascial components. Altered properties of the force transmission pathways of muscle (being either part of the myotendinous or myofascial pathways) due to TNX deficiency directly affect muscle function in TNX KO mice. Such effects are likely to contribute to muscle weakness experienced by patients with Ehlers-Danlos syndrome.
Delayed recovery of velocity-dependent power loss following eccentric actions of the ankle dorsiflexors
Authors: Power Geoffrey A. , Dalton Brian H. , Rice Charles L. , Vandervoort Anthony A.
Published: June 2010

Unaccustomed eccentric exercise has been shown to impair muscle function, although little is known regarding this impairment on muscle power. The purpose of this study was to investigate changes in neuromuscular properties of the ankle dorsiflexors during and after an eccentric contraction task and throughout recovery in 21 (10 men, 11 women) recreationally active young adults (25.8 ± 2.3 yr). All subjects performed 5 sets of 30 eccentric contractions at 80% of maximum isometric voluntary contraction (MVC) torque. Data were recorded at baseline, during the fatigue task, and for 30 min of recovery. There were no significant sex differences for all fatigue measures; thus data were pooled. After the fatigue task, MVC torque declined by 28% ( P < 0.05) and did not recover fully, and voluntary activation of the dorsiflexors, as assessed by the interpolated twitch technique, was near maximal (>99%) during and after the fatigue task ( P > 0.05). Peak twitch torque was reduced by 21% at 2 min of recovery and progressively decreased to 35% by 30 min ( P < 0.05). Low-frequency torque depression (10-to-50 Hz ratio) was present at 30 s of recovery, increased to 51% by 10 min, and did not recover fully ( P < 0.05). Velocity-dependent concentric power was reduced by 8% immediately after task termination and did not recover fully within 30 min ( P < 0.05). The main findings of an incomplete recovery of MVC torque, low-frequency torque depression, and shortening velocity indicate the presence of muscle damage, which may have altered excitation-contraction coupling and cross-bridge kinetics and reduced the number of functional sarcomeres in series, ultimately leading to velocity-dependent power loss.
Inhaled Granulocyte-Macrophage Colony Stimulating Factor for First Pulmonary Recurrence of Osteosarcoma: Effects on Disease-Free Survival and Immunomodulation. A Report From the Children's Oncology Group
Authors: Arndt Carola A.S. , Koshkina Nadya V. , Inwards Carrie Y. , Hawkins Douglas S. , Krailo Mark D. , Villaluna Doojduen , Anderson Peter M. , Goorin Allen M. , Blakely Martin L. , Bernstein Mark , Bell Sharon A. , Ray Kaylee , Grendahl Darryl C. , Marina Neyssa , Kleinerman Eugenie S.
Published: June 2010

Purpose: Osteosarcoma most commonly recurs in the lung. Based on preliminary data on the antitumor effects of granulocyte-macrophage colony stimulating factor (GM-CSF) in animal models, and promising phase I trials, we embarked on a feasibility study of inhaled GM-CSF in patients with first isolated pulmonary recurrence of osteosarcoma.

Experimental Design: Forty-three eligible patients received inhaled GM-CSF at doses from 250 to 1,750 μg twice daily on alternate weeks. Following two cycles, patients underwent thoracotomy to resect tumor and analyze pulmonary nodules for expression of Fas/Fas ligand (Fas/FasL), and the presence of dendritic cells by immunostaining for CD1a, clusterin, and S100. Following surgery, patients received 12 additional cycles of therapy on alternating weeks or until progression. Event-free survival and survival, and feasibility of therapy delivery were evaluated.

Results: Dose escalation to 1,750 μg twice daily was feasible with no dose-limiting toxicity. Mean scores for Fas/FasL in nodules from patients with bilateral recurrence who underwent unilateral thoracotomy pretreatment (using a scoring system of 0-3) were 1.3 and 0.88, respectively, compared with 0.78 and 0.62 in nodules resected following two cycles of therapy. Only 11 of 30 nodules postinhalation were positive for CD1a, 4 of 30 for S100, and 6 of 30 for clusterin. Event-free and overall survival at 3 years were 7.8% and 35.4%, respectively.

Conclusions: Inhalation of GM-CSF at doses from 250 to 1,750 μg twice daily on alternate weeks was feasible with low toxicity. However, no detectable immunostimulatory effect in pulmonary metastases or improved outcome postrelapse was seen. Clin Cancer Res; 16(15); 4024–30. ©2010 AACR.