bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectra MRSA, a New Chromogenic Agar Medium To Screen for Methicillin-ResistantStaphylococcus aureus
Authors: Peterson Jess F. , Riebe Katherine M. , Hall Gerri S. , Wilson Deborah , Whittier Susan , Palavecino Elizabeth , Ledeboer Nathan A.
Published: November 2009

A novel chromogenic medium, Spectra MRSA (Remel, Lenexa, KS), was designed to detect methicillin-resistantStaphylococcus aureus(MRSA) rapidly and more efficiently than traditional media (i.e., tryptic soy agar with 5% sheep blood [SBA] and mannitol salt agar [MSA]). A multicenter study (including four clinical trial sites and the Medical College of Wisconsin [MCW] Milwaukee, WI) compared the performance characteristics of Spectra MRSA to those of the traditional media for the detection of MRSA. For this study, 767 nasal swab specimens from the multicenter study (traditional medium used, SBA) and 667 nasal swab specimens from MCW (traditional medium used, MSA) were plated on each test medium and examined after 24 and 48 h of incubation. At 24 h, the sensitivity and the specificity of each medium were as follows: in the multicenter study, 95.4% and 99.7%, respectively, for Spectra MRSA and 93.6% and 100%, respectively, for SBA; at MCW, 95.2% and 99.5%, respectively, for Spectra MRSA and 88.7% and 94.0%, respectively, for MSA. The positive predictive values of each medium at 24 h were as follows: in the multicenter study, 98.1% for Spectra MRSA and 100% for SBA; at MCW, 95.2% for Spectra MRSA and 60.4% for MSA. In our evaluation, we found that Spectra MRSA was able to rapidly identify and differentiate methicillin-resistantS. aureusfrom methicillin-susceptibleS. aureuson the basis of the utilization of chromogens that result in denim blue colonies, thus eliminating the need for biochemical analysis and antimicrobial susceptibility testing. Extending the incubation beyond 24 h did not significantly improve the recovery of MRSA and resulted in decreased specificity.
Historical versus contemporary measures of seaweed biodiversity in the Bay of Fundy
Authors: Bates Colin R. , Saunders Gary W. , Chopin Thierry
Published: November 2009

Anthropogenic changes in many components of the Bay of Fundy biota have recently been reported, however a detailed assessment of benthic seaweed biodiversity has not been performed since the late 1970s. Here, we summarize 7 years (2000–2006) of temporal and spatial variation in species richness, composition, and percent cover of intertidal seaweeds in the outer Bay of Fundy, New Brunswick, Canada. In doing so, we provide up-to-date baseline records using repeatable and well-documented protocols. We document the presence of 72 species of seaweeds across four sites, and demonstrate that the biota at one of our sites is indicative of a degraded assemblage: large patches of unutilized substrate, low algal richness and abundance, with assemblages composed of hardy algal species and grazing and filter feeding invertebrates. Additionally, we compare these contemporary data with historical presence–absence records compiled from herbarium collections (1954–1978) and site surveys from 1963 to 1964 and 1978. Comparisons reveal 16 species not relocated in contemporary surveys. However, conclusions of anthropogenic changes in seaweed biodiversity are difficult to assess in the absence of high quality baseline information, and seaweeds historically found but not relocated in current sampling are easily misidentified, subtidal, or rare. We discuss the nature and value of baseline data, and make suggestions for future research.
Population genetic structure of the Gulf of St. Lawrence aster,Symphyotrichum laurentianum(Asteraceae), a threatened coastal endemic
Authors: Heard Stephen B. , Jesson Linley K. , Tulk Kirby
Published: November 2009

The Gulf of St. Lawrence aster ( Symphyotrichum laurentianum (Fernald) G.L. Nesom) is an endemic annual of saline habitats in the southern Gulf of St. Lawrence. It is listed as a threatened species, and has recently experienced population declines in much of its range. We used 11 allozyme markers to assay population genetic variation in six wild populations of S. laurentianum from the Magdalen Islands, Quebec (QC), the only remaining wild population from Prince Edward Island National Park (PEI), and a greenhouse population founded in 1999 with seed collected from PEI. Symphyotrichum laurentianum harbours moderate genetic diversity (Ps= 0.36, As= 1.54), with only modest spatial genetic structure (pairwise FST < 0.15) and no significant isolation by distance. The PEI population had greatly reduced allelic diversity compared with the populations from the Magdalen Islands, which likely act as a reservoir of genetic variation in S. laurentianum. Recent loss of alleles during population decline in PEI is suggested by the retention of greater allelic diversity in the greenhouse population. Estimates of breeding structure suggest small but nonzero rates of outcross pollination (FIS= 0.73, 95% CI = 0.48–0.97; outcrossing rate ∼16%). Population genetic structure in S. laurentianum can inform those forming and carrying out conservation and recovery plans for this threatened species.
Oomycete and chytrid infections of the marine diatom Pseudo-nitzschia pungens (Bacillariophyceae) from Prince Edward Island, Canada
Authors: Hanic Louis A. , Sekimoto Satoshi , Bates Stephen S.
Published: November 2009

Two eukaryotic parasites were found infecting the bloom-forming marine diatom Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle in Prince Edward Island, Canada. The most common was an oomycete; the other, seen once, was a chytrid. The structure of the discharged sporangium of both is remarkably similar. The oomycete parasite caused the host cell to lay down several extra girdle bands as the parasite thallus grew and swelled to form a holocarpic, endobiotic, nonwalled multinucleate thallus within the host cytoplasm. At maturity the thallus formed a single discharge tube with a thickened base and a thin papillate apex. Many biflagaellate zoospores were formed that burst out from the discharge tube. Ultrastructural characteristics of the oomycete thallus include mitochondria with tubular cristae and vesicles with dense body inclusions, features common to the oomycetes. The morphological characteristics and biflagellate condition indicate a placement of this form in the genus Ectrogella . However, neither flagellar mastigonemes nor flagella flimmer vesicles were found. The absence of flimmers may indicate a closer phylogenetic relationship to Haptoglossa , an endoparasitic oomycete of nematodes, the zoospores of which lack flagellar mastigonemes. Cell infection frequencies ranged from 0.6%–15.9% during 1992–1995, at the four sampling sites.
DoesDryas integrifoliafix nitrogen?
Authors: Markham John H.
Published: November 2009

Symbiotic nitrogen fixation is found in plant taxa that also include non-nitrogen-fixing members. Strong evidence for the occurrence of nitrogen fixation comes from physiological measurements and the identification of the nitrogen fixing symbiont. This evidence has been provided for Dryas drummondii Richardson ex Hook. in the Rosaceae. However, while there have been numerous references to the nitrogen fixing ability of Dryas integrifolia Vahl., they can all be traced to a single report that did not provide strong evidence for nitrogen fixation. My attempts to establish nitrogen fixing nodules on vegetatively propagated plants from the field, or seedlings of D. integrifolia, using three different sources of Frankia , all failed. Since other host plants ( Alnus viridis (Chaix) DC. subsp. crispa (Aiton) Turrill and Purshia tridentata (Pursh.) DC.) did produce nitrogen-fixing nodules under the same growth conditions, the ability of D. integrifolia to fix nitrogen should be considered suspect.
Eocene and Neogene volcanic rocks in the southeastern Nechako Basin, British Columbia: interpretation of the Canadian Hunter seismic reflection surveys using first-arrival tomography
Authors: Hayward Nathan , Calvert Andrew J.
Published: November 2009

Geological investigation of the near-surface in the southeastern Nechako Basin is difficult. Shallow seismic reflection imaging is poor due in part to an extensive cover of Eocene and Neogene volcanic rocks. Outcrops of these volcanic rocks, and the primarily Cretaceous bedrock, are commonly obscured by Quaternary deposits and vegetation. Estimates of near-surface P-wave velocity are derived from the tomographic inversion of seismic first-arrivals, an effective tool when seismic imaging is poor. Tomographic model velocities are in agreement with sonic logs and laboratory samples, except for those from the Neogene Chilcotin Group. Cretaceous sedimentary rocks have velocities of ∼2800–4200 ms–1. The Eocene Endako and Ootsa Lake groups, which have velocities of ∼3000–4200 ms–1, are not distinguishable based on velocity. The velocity, the character (density, focus, and penetration depth) of rays, and ties with well and surface geology constrain the subsurface extent of the Endako Group adjacent to well b-82-C. The Chilcotin Group typically exhibits velocities (∼2400–3000 ms–1) lower than corresponding velocities from sonic logs (4500–5200 ms–1) and laboratory measurements (5000–5200 ms–1). These low model velocities may be due to the presence of high porosity, brecciated rocks near to the surface, in comparison with the other measurements that have focussed on lower porosity massive lavas. The lowest mean velocities, located to the southeast, are related to anomalously thick, high porosity, breccia-rich deposits of Chilcotin Group. This conclusion is consistent with the interpretation that the Chilcotin Group is thicker in paleo river valleys.
A new ankylosaur (Dinosauria: Ankylosauria) from the Lower Cretaceous Cloverly Formation of central Montana
Authors: Parsons William L. , Parsons Kristen M.
Published: November 2009

A cranium and other associated skeletal elements representing a new ankylosaurid dinosaur, Tatankacephalus cooneyorum gen. et sp. nov. possess several diagnostic features that indicate that this new taxon differs from the only other known ankylosaur from the Cloverly Formation, Sauropelta edwardsorum . These features include a frontoparietal dome, an enlarged nuchal ridge that obscures the occipital region, a circular orbit, ventral curvature in the posterolaterally directed paroccipital processes, a posteroventrally directed foramen magnum, and a number of features on the braincase. The phylogenetic analysis positions Tatankacephalus with Ankylosauridae based on its sharing of several characters with other members of this clade, including an enlarged nuchal segment that obscures the occiput in dorsal view, a ventrally curving lateral profile of the cranium anterior to the orbit, pyramidal postorbital boss, laterally projecting pyramidal quadratojugal boss, the presence of a postocular shelf, the presence of paranasal sinuses, and the lack of a cingulum on a maxillary (or dentary) tooth. It is considered a basal member of Ankylosauridae because it retains premaxillary teeth and a visible lateral temporal fenestra, in contrast to the absence of premaxillary teeth and an obscured lateral temporal fenestra in younger members of this clade.
Holmograptus spinosus and the Middle Ordovician (Darriwilian) graptolite biostratigraphy at Les Méchins (Quebec, Canada)
Authors: Maletz Jörg
Published: November 2009

The Les Méchins region in Quebec provides a unique opportunity to understand the Darriwilian graptolite succession in eastern North America. The graptolite faunas of the upper member of the Anse au Crapaud Formation include the Arienigraptus gracilis , Oncograptus upsilon , Undulograptus austrodentatus , and Holmograptus spinosus biozone faunas and, thus, complement the well known Darriwilian faunas of the Cow Head, Table Head, and Goose Tickle groups of western Newfoundland. In particular, the Holmograptus spinosus Biozone interval of calcarenitic limestones bears a rare combination of benthic (shelly) and planktic (graptolitic) faunas with conodonts, brachiopods, ostracods, sponge spicules, and algal remains associated with common graptolites that allow an inter-continental correlation. The Holmograptus spinosus Biozone is introduced for the interval based on a diverse and characteristic graptolite fauna. The fauna includes among others, Atopograptus woodwardi , recognized for the first time in North America. The Holmograptus spinosus Biozone fauna can be found worldwide and is easily correlated into the conodont biofacies using species of the genus Histiodella . Ties between graptolite and conodont biozonations are discussed for the Darriwilian. Silicified ostracods are illustrated for the first time from the interval. Hustedograptus quebecensis is described as new.
The Lower Triassic Sulphur Mountain Formation in the Wapiti Lake area: lithostratigraphy, conodont biostratigraphy, and a new biozonation for the lower Olenekian (Smithian)Earth Science Sector (ESS) Contribution 20080714.
Authors: Orchard M. J. , Zonneveld J.-P.
Published: November 2009

The Sulphur Mountain Formation in the Wapiti area is subdivided into the Phroso, Meosin Mountain (new), and Vega members, which collectively span much of the Lower Triassic. The Smithian conodont faunas are particularly well developed and form the basis of three partly new conodont zones and two new subzones: the lachrymiformis Zone, meeki Zone, and mosheri Zone, with the last subdivided into the phryna and milleri Subzones. An informal lowermost Smithian nepalensis interval is introduced, although it has yet to be found in the area. The Phroso Member is latest Griesbachian, Dienerian, and, in its uppermost part, Smithian, specifically the lachrymiformis and meeki zones: these are shown to be equivalent to the Euflemingites romunduri ammonoid Zone. The Meosin Mountain Member is assigned to the meeki Zone in its lower part and the phryna Subzone of the mosheri Zone in its upper part: at least, the upper part of the mosheri Zone is equivalent to the Anawasatchites tardus ammonoid Zone. The Mackenzie Dolomite Lentil is at least partly older than the Meosin Mountain Member, and age equivalence of subsurface turbidite units in the Montney Formation should not be assumed. The lowermost Vega Member is also assigned to the phryna Subzone, and higher parts of that member span both the milleri Subzone of the Smithian and the entire Spathian. The following new conodont taxa are described: Neogondolella ? joanae , Novispathodus latiformis , Scythogondolella lachrymiformis , Sc. phryna , and Sc. rhomboidea ; several other new species are kept in open nomenclature.
FROM SUBFACTOR PLANAR ALGEBRAS TO SUBFACTORS
Authors: KODIYALAM VIJAY , SUNDER V. S.
Published: November 2009

We present a purely planar algebraic proof of the main result of a paper of Guionnet–Jones–Shlaykhtenko which constructs an extremal subfactor from a subfactor planar algebra whose standard invariant is given by that planar algebra.
SUBSETS OF THE GENERAL SIERPINSKI CARPET WITH MIXED GROUP FREQUENCIES
Authors: GUI YONGXIN , LI WENXIA
Published: November 2009

We consider a class of subsets of the general Sierpinski carpet which is characterized by insisting that the allowed digits in the expansion occur with prescribed mixing group frequencies, determine their Hausdorff dimensions and give the necessary and sufficient conditions for their corresponding Hausdorff measures to be positive and finite.
ORIENTED BIVARIANT THEORIES, I
Authors: YOKURA SHOJI
Published: November 2009

In 1981 W. Fulton and R. MacPherson introduced the notion of bivariant theory (BT), which is a sophisticated unification of covariant theories and contravariant theories. This is for the study of singular spaces. In 2001 M. Levine and F. Morel introduced the notion of algebraic cobordism, which is a universal oriented Borel–Moore functor with products (OBMF) of geometric type, in an attempt to understand better V. Voevodsky's (higher) algebraic cobordism. In this paper we introduce a notion of oriented bivariant theory (OBT), a special case of which is nothing but the oriented Borel–Moore functor with products. The present paper is a first one of the series to try to understand Levine–Morel's algebraic cobordism from a bivariant theoretical viewpoint, and its first step is to introduce OBT as a unification of BT and OBMF.
FUNDAMENTAL LIMITS: DEVELOPING NEW TOOLS FOR A BETTER UNDERSTANDING OF SECOND-ORDER MOLECULAR NONLINEAR OPTICS
Authors: PÉREZ-MORENO JAVIER , CLAYS KOEN
Published: November 2009

The generalized Thomas-Kuhn sum rules are used to characterize the nonlinear optical response of organic chromophores in terms of fundamental parameters that can be measured experimentally. The nonlinear optical performance of organic molecules is evaluated from the combination of hyper-Rayleigh scattering measurements and the analysis in terms of the fundamental limits. Different strategies for the enhancement of nonlinear optical behavior at the molecular and supramolecular level are evaluated and new paradigms for the design of more efficient nonlinear optical molecules are proposed and investigated.
THE COMPARISON NONLINEARITY BEHAVIORS OF PHOTONIC CRYSTAL FIBER BY TWO REDUCED LENGTHS OF BI-EDF IN RING CAVITY
Authors: SHAHI S. , MOGHADDAM M. R. A. , HARUN S. W. , AHMAD H.
Published: November 2009

The nonlinearity effects of photonic crystal fiber (PCF) in a ring resonator for different lengths of Bismuth erbium-doped fiber (Bi-EDF) as the Brillouin gain medium is investigated. Bi-EDF (215 cm) itself has high stimulated Brillouin effect at 150 mW that is generated at 1480 nm pump power. The proposed Brillouin fiber laser (BFL) with PCF operates at 1559 nm for 49 cm Bi-EDF, which is upshifted by 0.08 nm from the Brillouin pump with a side-mode suppression ratio more than 12 dB. As a result of using reduced length of PCF and two long Bi-EDF, the BFL is stable at room temperature and compact in this report.
SPECTRAL WIDTH VARIATION OF ULTRASHORT LASER PULSES IN MONOMODE OPTICAL FIBERS
Authors: KBASHI HANI JASSIM , JAWAD HUSSEIN , AL-NAIMEE KAIS A. , BENOCCI ROBERTO , CARPEGGIANI PAOLO , PEREGO CLAUDIO , BATANI DIMITRI
Published: November 2009

Femtosecond laser pulse propagation in monomode optical fibers is demonstrated and investigated numerically (by simulations) and experimentally in this paper. A passively mode locked Nd:glass laser giving a pulse duration of about 200 fsec at 1053 nm wavelength and 120 mW average optical power with 100 MHz repetition rate is used in the experimental work. Numerical simulations are done by solving the nonlinear Schrödinger equation with the aid of Matlab program. The results show that self phase modulation (SPM) leads to compression of the spectral width from 5 nm to 2.1 nm after propagation of different optical powers (34, 43, 86 and 120 mW) in fibers of different length (5, 15, 35 m). The varying optical powers produced a varying phase shift. The output spectral width also changed with the fiber length at a given peak power.
Parametric polymorphism for XML
Authors: Hosoya Haruo , Frisch Alain , Castagna Giuseppe
Published: November 2009

Despite the extensiveness of recent investigations on static typing for XML, parametric polymorphism has rarely been treated. This well-established typing discipline can also be useful in XML processing in particular for programs involving “parametric schemas,” that is, schemas parameterized over other schemas (e.g., SOAP). The difficulty in treating polymorphism for XML lies in how to extend the “semantic” approach used in the mainstream (monomorphic) XML type systems. A naive extension would be “semantic” quantification over all substitutions for type variables. However, this approach reduces to an NEXPTIME-complete problem for which no practical algorithm is known and induces a subtyping relation that may not always match the programmer's intuition. In this article, we propose a different method that smoothly extends the semantic approach yet is algorithmically easier. The key idea here is to devise a novel and simplemarkingtechnique, where we interpret a polymorphic type as a set of values with annotations of which subparts are parameterized. We exploit this interpretation in every ingredient of our polymorphic type system such as subtyping, inference of type arguments, etc. As a result, we achieve a sensible system that directly represents a usual expected behavior of polymorphic type systems—“values of abstract types are never reconstructed”—in a reminiscence of Reynold's parametricity theory. Also, we obtain a set of practical algorithms for typechecking by local modifications to existing ones for a monomorphic system.
Touchable 3D video system
Authors: Cha Jongeun , Eid Mohamad , Saddik Abdulmotaleb El
Published: November 2009

Multimedia technologies are reaching the limits of providing audio-visual media that viewers consume passively. An important factor, which will ultimately enhance the user's experience in terms of impressiveness and immersion, is interaction. Among daily life interactions, haptic interaction plays a prominent role in enhancing the quality of experience of users, and in promoting physical and emotional development. Therefore, a critical step in multimedia research is expected to bring the sense of touch, or haptics, into multimedia systems and applications. This article proposes a touchable 3D video system where viewers can actively touch a video scene through a force-feedback device, and presents the underlying technologies in three functional components: (1) contents generation, (2) contents transmission, and (3) viewing and interaction. First of all, we introduce a depth image-based haptic representation (DIBHR) method that adds haptic and heightmap images, in addition to the traditional depth image-based representation (DIBR), to encode the haptic surface properties of the video media. In this representation, the haptic image contains the stiffness, static friction, and dynamic friction, whereas the heightmap image contains roughness of the video contents. Based on this representation method, we discuss how to generate synthetic and natural (real) video media through a 3D modeling tool and a depth camera, respectively. Next, we introduce a transmission mechanism based on the MPEG-4 framework where new MPEG-4 BIFS nodes are designed to describe the haptic scene. Finally, a haptic rendering algorithm to compute the interaction force between the scene and the viewer is described. As a result, the performance of the haptic rendering algorithm is evaluated in terms of computational time and smooth contact force. It operates marginally within a 1 kHz update rate that is required to provide stable interaction force and provide smoother contact force with the depth image that has high frequency geometrical noise using a median filter.
Video interactions in online video social networks
Authors: Benevenuto Fabrício , Rodrigues Tiago , Almeida Virgilio , Almeida Jussara , Ross Keith
Published: November 2009

This article characterizes video-based interactions that emerge from YouTube's video response feature, which allows users to discuss themes and to provide reviews for products or places using much richer media than text. Based on crawled data covering a representative subset of videos and users, we present a characterization from two perspectives: the video response view and the interaction network view. In addition to providing valuable statistical models for various characteristics, our study uncovers typical user behavioral patterns in video-based environments and shows evidence of opportunistic behavior.
Improving the extraction of bilingual terminology from Wikipedia
Authors: Erdmann Maike , Nakayama Kotaro , Hara Takahiro , Nishio Shojiro
Published: November 2009

Research on the automatic construction of bilingual dictionaries has achieved impressive results. Bilingual dictionaries are usually constructed from parallel corpora, but since these corpora are available only for selected text domains and language pairs, the potential of other resources is being explored as well.

In this article, we want to further pursue the idea of using Wikipedia as a corpus for bilingual terminology extraction. We propose a method that extracts term-translation pairs from different types of Wikipedia link information. After that, an SVM classifier trained on the features of manually labeled training data determines the correctness of unseen term-translation pairs.
Approximation algorithms for data placement on parallel disks
Authors: Golubchik Leana , Khanna Sanjeev , Khuller Samir , Thurimella Ramakrishna , Zhu An
Published: November 2009

We study an optimization problem that arises in the context of data placement in a multimedia storage system. We are given a collection of
M
multimedia objects (data objects) that need to be assigned to a storage system consisting of
N
disks
d
1
,
d
2
…,

d
N

. We are also given sets
U
1
,
U
2
,…,

U
M

such that

U
i

is the set of clients seeking the
i
th data object. Each disk

d
j

is characterized by two parameters, namely, its
storage capacity

C
j

which indicates the maximum number of data objects that may be assigned to it, and a
load capacity

L
j

which indicates the maximum number of clients that it can serve. The goal is to find a placement of data objects to disks and an assignment of clients to disks so as to maximize the total number of clients served, subject to the capacity constraints of the storage system.

We study this data placement problem for two natural classes of storage systems, namely,
homogeneous
and
uniform ratio
. We show that an algorithm developed by Shachnai and Tamir [2000a] for data placement achieves the
best possible
absolute bound regarding the number of clients that can always be satisfied. We also show how to implement the algorithm so that it has a running time of
O
((
N
+
M
) log(
N
+
M
)). In addition, we design a polynomial-time approximation scheme, solving an open problem posed in the same paper.
Sublinear estimation of entropy and information distances
Authors: Guha Sudipto , McGregor Andrew , Venkatasubramanian Suresh
Published: November 2009

In many data mining and machine learning problems, the data items that need to be clustered or classified are not arbitrary points in a high-dimensional space, but are distributions, that is, points on a high-dimensional simplex. For distributions, natural measures are not ℓpdistances, but information-theoretic measures such as the Kullback-Leibler and Hellinger divergences. Similarly, quantities such as the entropy of a distribution are more natural than frequency moments. Efficient estimation of these quantities is a key component in algorithms for manipulating distributions. Since the datasets involved are typically massive, these algorithms need to have only sublinear complexity in order to be feasible in practice.

We present a range of sublinear-time algorithms in various oracle models in which the algorithm accesses the data via an oracle that supports various queries. In particular, we answer a question posed by Batu et al. on testing whether two distributions are close in an information-theoretic sense given independent samples. We then present optimal algorithms for estimating various information-divergences and entropy with a more powerful oracle called the combined oracle that was also considered by Batu et al. Finally, we consider sublinear-space algorithms for these quantities in the data-stream model. In the course of doing so, we explore the relationship between the aforementioned oracle models and the data-stream model. This continues work initiated by Feigenbaum et al. An important additional component to the study is considering data streams that are ordered randomly rather than just those which are ordered adversarially.
A better approximation ratio for the vertex cover problem
Authors: Karakostas George
Published: November 2009

We reduce the approximation factor for the vertex cover to 2 − Θ (1/√log
n
) (instead of the previous 2 − Θ ln ln
n
/2ln
n
obtained by Bar-Yehuda and Even [1985] and Monien and Speckenmeyer [1985]). The improvement of the vanishing factor comes as an application of the recent results of Arora et al. [2004] that improved the approximation factor of the sparsest cut and balanced cut problems. In particular, we use the existence of two big and well-separated sets of nodes in the solution of the semidefinite relaxation for balanced cut, proven by Arora et al. [2004]. We observe that a solution of the semidefinite relaxation for vertex cover, when strengthened with the triangle inequalities, can be transformed into a solution of a balanced cut problem, and therefore the existence of big well-separated sets in the sense of Arora et al. [2004] translates into the existence of a big independent set.
Parametric analysis for ungapped Markov models of evolution
Authors: Fernández-Baca David , Venkatachalam Balaji
Published: November 2009

Efficient sensitivity analysis algorithms are presented for two problems arising in the study of Markov models of sequence evolution: ancestral reconstruction in evolutionary trees and local ungapped alignment under log-odds scoring. The algorithms generate complete descriptions of the optimum solutions for all possible values of the evolutionary distance. The running time for the parametric ancestral reconstruction problem under the Kimura 2-parameter model is
O
(
kn
+
kn
2/3
log
k
), where
n
is the number of sequences and
k
is their length, assuming all edges have the same length. For the parametric gapless alignment problem under the Jukes-Cantor model, the running time is
O
(
mn
+
mn
2/3
log
m
), where
m
and
n
are the sequence lengths and
n
≤
m
.
Low-dimensional lattice basis reduction revisited
Authors: Nguyen Phong Q. , Stehlé Damien
Published: November 2009

Lattice reduction is a geometric generalization of the problem of computing greatest common divisors. Most of the interesting algorithmic problems related to lattice reduction are NP-hard as the lattice dimension increases. This article deals with the low-dimensional case. We study a greedy lattice basis reduction algorithm for the Euclidean norm, which is arguably the most natural lattice basis reduction algorithm because it is a straightforward generalization of an old two-dimensional algorithm of Lagrange, usually known as Gauss' algorithm, and which is very similar to Euclid's gcd algorithm. Our results are twofold. From a mathematical point of view, we show that up to dimension four, the output of the greedy algorithm is optimal: The output basis reaches all the successive minima of the lattice. However, as soon as the lattice dimension is strictly higher than four, the output basis may be arbitrarily bad as it may not even reach the first minimum. More importantly, from a computational point of view, we show that up to dimension four, the bit-complexity of the greedy algorithm is quadratic without fast integer arithmetic, just like Euclid's gcd algorithm. This was already proved by Semaev up to dimension three using rather technical means, but it was previously unknown whether or not the algorithm was still polynomial in dimension four. We propose two different analyzes: a global approach based on the geometry of the current basis when the length decrease stalls, and a local approach showing directly that a significant length decrease must occur every
O
(1) consecutive steps. Our analyzes simplify Semaev's analysis in dimensions two and three, and unify the cases of dimensions two to four. Although the global approach is much simpler, we also present the local approach because it gives further information on the behavior of the algorithm.
Defining strong privacy for RFID
Authors: Juels Ari , Weis Stephen A.
Published: November 2009

In this work, we consider privacy in Radio Frequency IDentification (RFID) systems. Our contribution is twofold: (i) We propose a simple, formal definition of strong privacy useful for basic analysis of RFID systems, as well as a different (weaker) definition applicable to multiverifier systems; (ii) We apply our definition to reveal vulnerabilities in several proposed privacy-enhancing RFID protocols; and (iii) We formally analyze and suggest improvements to hash-locks, one of the first privacy-enhancing RFID protocols in the literature.
Regular tree languages definable in FO and in FO

mod
Authors: Benedikt Michael , Segoufin Luc
Published: November 2009

We consider regular languages of labeled trees. We give an effective characterization of the regular languages over such trees that are definable in first-order logic in the language of labeled graphs. These languages are the analog on trees of the “locally threshold testable” languages on strings. We show that this characterization yields a decision procedure for determining whether a regular tree language is first-order definable: The procedure is polynomial time in the minimal automaton presenting the regular language. We also provide an algorithm for deciding whether a regular language is definable in first-order logic supplemented with modular quantifiers.
A comparative study of motivational differences for online shopping
Authors: Sangwan Sunanda , Siguaw Judy A. , Guan Chong
Published: November 2009

Purchasing through online retailers, electronic markets, and virtual communities has its value. Often motivations to buy online differ from those in an offline environment and these motivations may be more incongruent for online shoppers dispersed globally. In this study, motives to purchase in an electronic environment in the context of two countries are studied. Two data sets of 538 respondents (304 in Singapore and 279 in China) were collected. Results show that there is a significant difference in motivations in China and Singapore buyers, and Singapore buyers have higher positive need gratifications. These findings indicate that Singapore buyers are more positively inclined toward online shopping, and they are likely to be more gratified when buying online than respondents from China. In country specific contexts, no motivational differences for male and female respondents are observed. However, gender is significant for the combined sample indicating that overall male and female populations have different motivations for online shopping. Online retailers could benefit from focusing on aspects that address perceptions of positive need-fulfillment on their e-commerce sites for the Singapore and Chinese market segments, while also differentiating websites for online markets by gender.
Mobile commerce adoption in China and the United States
Authors: Dai Hua , Palvi Prashant C.
Published: November 2009

Mobile communication technologies have penetrated consumer markets throughout the world. Mobile commerce is likely to make a strong influence on business activities, consumer behavior, as well as national and global markets. Thus the identification of factors that influence mobile commerce adoption has significant value. In a global context, this study identified nine factors affecting mobile commerce adoption based on published research in MIS. These factors were investigated in China and the United States, and a comparative examination was conducted. A survey was conducted on 190 individual mobile commerce users in China and USA. Results show that there are several significant differences among the antecedents and their impacts on consumer intention to use mobile commerce in the two cultural settings. The study provides a number of practical insights and informs vendors seeking to enter the Chinese and the US marketplace with specific information on user perspectives.
Differences in e-commerce behavior between neighboring countries
Authors: Goethals Frank G. , Carugati Andrea , Leclercq Aurélie
Published: November 2009

It is often (implicitly) assumed that e-commerce behavior is similar in countries with a similar culture in terms of Hofstede's dimensions. Through a study of e-commerce behavior of 969 private consumers and company representatives on 50 products, this paper proves there are actually significant differences in e-commerce behavior (information finding, suppler selection, and purchase) between people from two neighboring, culturally similar countries: Belgium and France. Furthermore, contrary to what was found in various US studies, very few differences in e-commerce behavior were detected between men and women in these two countries. Furthermore, clear differences were detected between age groups for product information finding and supplier selection but not for product purchase. Finally, to a big extent differences in e-commerce behavior between private consumers of two countries also exist between company representatives of the two countries.
AICAR and metformin, but not exercise, increase muscle glucose transport through AMPK-, ERK-, and PDK1-dependent activation of atypical PKC
Authors: Sajan M. P. , Bandyopadhyay G. , Miura A. , Standaert M. L. , Nimal S. , Longnus S. L. , Van Obberghen E. , Hainault I. , Foufelle F. , Kahn R. , Braun U. , Leitges M. , Farese R. V.
Published: November 2009

Activators of 5′-AMP-activated protein kinase (AMPK) 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), metformin, and exercise activate atypical protein kinase C (aPKC) and ERK and stimulate glucose transport in muscle by uncertain mechanisms. Here, in cultured L6 myotubes: AICAR- and metformin-induced activation of AMPK was required for activation of aPKC and ERK; aPKC activation involved and required phosphoinositide-dependent kinase 1 (PDK1) phosphorylation of Thr410-PKC-ζ; aPKC Thr410 phosphorylation and activation also required MEK1-dependent ERK; and glucose transport effects of AICAR and metformin were inhibited by expression of dominant-negative AMPK, kinase-inactive PDK1, MEK1 inhibitors, kinase-inactive PKC-ζ, and RNA interference (RNAi)-mediated knockdown of PKC-ζ. In mice, muscle-specific aPKC (PKC-λ) depletion by conditional gene targeting impaired AICAR-stimulated glucose disposal and stimulatory effects of both AICAR and metformin on 2-deoxyglucose/glucose uptake in muscle in vivo and AICAR stimulation of 2-[3H]deoxyglucose uptake in isolated extensor digitorum longus muscle; however, AMPK activation was unimpaired. In marked contrast to AICAR and metformin, treadmill exercise-induced stimulation of 2-deoxyglucose/glucose uptake was not inhibited in aPKC-knockout mice. Finally, in intact rodents, AICAR and metformin activated aPKC in muscle, but not in liver, despite activating AMPK in both tissues. The findings demonstrate that in muscle AICAR and metformin activate aPKC via sequential activation of AMPK, ERK, and PDK1 and the AMPK/ERK/PDK1/aPKC pathway is required for metformin- and AICAR-stimulated increases in glucose transport. On the other hand, although aPKC is activated by treadmill exercise, this activation is not required for exercise-induced increases in glucose transport, and therefore may be a redundant mechanism.
Effects of experimental weight perturbation on skeletal muscle work efficiency, fuel utilization, and biochemistry in human subjects
Authors: Goldsmith Rochelle , Joanisse Denis R. , Gallagher Dympna , Pavlovich Katherine , Shamoon Elisabeth , Leibel Rudolph L. , Rosenbaum Michael
Published: November 2009

Maintenance of a body weight 10% above or below that “customary” for lean or obese individuals results in respective increases or decreases in the energy expended in low levels of physical activity (nonresting energy expenditure, NREE). These changes are greater than can be accounted for by the altered body weight or composition and are due mainly to altered skeletal muscle work efficiency at low levels of power generation. We performed biochemical analysis of vastus lateralis muscle needle biopsy samples to determine whether maintenance of an altered body weight was associated with changes in skeletal muscle histomorphology. We found that the maintenance of a 10% reduced body weight was associated with significant declines in glycolytic (phosphofructokinase, PFK) enzyme activity and, in particular, in the ratio of glycolytic to oxidative (cytochrome c oxidase, COX) enzyme activity without significant changes in the activities of enzymes relevant to mitochondrial density, respiratory chain activity, or fuel transport; or in skeletal muscle fiber type or glycogen stores. The fractional change in the ratio of PFK/COX activity in subjects following weight loss was significantly correlated with changes in the systemic respiratory exchange ratio (RER) and measures of mechanical efficiency of skeletal muscle at low workloads (pedaling a bicycle to generate 10 or 25 W of power). Thus, predictable changes in systemic skeletal muscle biochemistry accompany the maintenance of an altered body weight and account for a significant portion of the variance in skeletal muscle work efficiency and fuel utilization at reduced body weight.
Tendinopathy alters mechanical and material properties of the Achilles tendon
Authors: Arya Shruti , Kulig Kornelia
Published: November 2009

The purpose of this study was to investigate the in vivo material and mechanical properties of the human Achilles tendon in the presence of tendinopathy. Real-time ultrasound imaging and dynamometry were used to assess Achilles tendon stiffness, Young's modulus, stress, strain, and cross-sectional area (CSA) in 12 individuals with Achilles tendinopathy and 12 age- and gender-matched controls. The results of this study suggest that tendinopathy weakens the mechanical and material properties of the tendon. Tendinopathic tendons had greater CSA, lower tendon stiffness, and lower Young's modulus. These alterations in mechanical characteristics may put the Achilles tendon at a higher risk to sustain further injury and prolong the time to recovery. Results from this study may be used to design treatment strategies that specifically target these deficits, leading to faster and permanent recovery from tendinopathy.
Targeted disruption of nuclear factor erythroid-derived 2-like 1 in osteoblasts reduces bone size and bone formation in mice
Authors: Kim Jonghyun , Xing Weirong , Wergedal Jon , Chan Jefferson Y. , Mohan Subburaman
Published: November 2009

Previous in vitro studies found that nuclear factor erythroid-derived 2-like 1 (NFE2L1) was involved in mediating ascorbic acid-induced osterix expression and osteoblast differentiation via binding to the antioxidant response element of the osterix promoter. To test the role of NFE2L1 in regulating bone formation in vivo, we disrupted NFE2L1 specifically in osteoblasts. Mice expressing Cre under the control of Col1α2 promoter were crossed with NFE2L1 loxP mice to generate Cre+ knockout (KO) and Cre− wild-type (WT) mice. Skeletal measurements by DEXA revealed 8–10% and 9–11% reduction in total body BMC and bone area in the KO mice from 3 to 8 wk of age. Peripheral quantitative computed tomography analyses found both periosteal and endosteal circumferences were reduced by 6% at the middiaphysis of the femurs from 8 wk old KO mice. Histomorphometric analyses revealed reduced bone formation was a cause for reduced bone size in the KO mice. Microcomputed tomography analysis of the metaphysis of the femur revealed that trabecular bone volume/total volume, and trabecular numbers were decreased by 30 and 53% in the NFE2L1 KO mice. Expression of osterix was decreased by 57% in the bones of NFE2L1 KO mice. In vitro nodule assay demonstrated that mineralized nodule area was reduced by 68% in the cultures of bone marrow stromal cells from NFE2L1 KO mice. Treatment of primary osteoblasts with ascorbic acid increased osterix expression by fourfold, whereas loss of NFE2L1 in osteoblasts diminished ascorbic acid stimulation of osterix expression by 50%. Our data provide the first in vivo experimental evidence that NFE2L1 produced by osteoblasts is involved in regulating osterix expression, osteoblast differentiation, and bone formation.
Prevalence of Metabolic Syndrome in an Adult Urban Population of the West of Iran
Authors: Sharifi F. , Mousavinasab S. N. , Saeini M. , Dinmohammadi M.
Published: November 2009

Objectives. We determine the prevalence of the metabolic syndrome in an urban population of Zanjan, a province located to the west of Tehran.Methods. Randomly selected adults>20 years were studied using stratified sampling. Target study sample was 2941 (1396 males and 1545 females). Metabolic syndrome was diagnosed using Adult Treatment Panel-III (ATP-III) guidelines when any three of the following were present: central obesity, raised triglycerides≥150 mg/dl, low high-density lipoprotein (HDL) cholesterol, blood pressure≥130/≥85 mm Hg, and diabetes or fasting plasma glucose (FPG)≥100 mg/dl.Results. Metabolic syndrome was present in 697 (23.7%) subjects (CI 95%:22%–25%,P= .001), prevalence was 23.1% in men and 24.4% in women (P: .4). The prevalence increased from 7.5% in the population younger than 30 y to 45.6% in ages more than 50 years. Low HDL was the most common metabolic abnormality in both sexes. Most of those with metabolic syndrome had three components of the syndrome (75.6%), 170 subjects (24.4%) had four and none had five components simultaneously. The prevalence of obesity (BMI≥30 kg/m2), hypercholesterolemia (≥200 mg/dl) and high LDL cholesterol (≥130 mg/dl) was greater in the metabolic syndrome group than normal subjects (P= .00).Conclusions. There is a high prevalence of metabolic syndrome in this urban population of the northern west of Iran. Focus of cardiovascular prevention should be undertaken in this area.
Rare Lipomatous Tumors with Osseous and/or Chondroid Differentiation in the Oral Cavity Report of Two Cases and Review of the Literature
Authors: Kuyama Kayo , Fifita Sisilia Fusi , Komiya Masamichi , Sun Yan , Akimoto Yoshiaki , Yamamoto Hirotsugu
Published: November 2009

The purpose of this study was to determine the clinicopathological and immunohistochemical features of lipoma/fibrolipoma with rare occasions as osseous and/or chondroid differentiation in the oral cavity. Two cases of the tumors, who presented with a painless, relatively hard mass on the oral mucosa, were studied. These were consisted of a well-circumscribed mass of fatty tissue with chondroid and significant fibrous component intermixed with the lobules of fat cells with chondroid and woven bone component, respectively. Immunohistochemical study revealed that peripheral spindle cells around chondroid tissue stained diffusely for S-100 & and Sox-9, though peripheral spindle cells around osteoid tissue only stained for RUNX-2. According to review of the literature, lipoma/fibrolipoma with osseous and/or chondroid differentiation was 18 cases. Also fibrolipoma with osseous and chondroid differentiation is the first to be reported here. These results indicated that the cartilage/bone is produced by differentiation of undifferentiated mesenchymal cells of stroma.
Another Representation for the Maximal Lie Algebra of sl(n + 2, ℝ) in Terms of Operators
Authors: Feroze Tooba , Qadir Asghar
Published: November 2009

We provide an alternate representation to the result that the Lie algebra of generators of the system of n differential equations, (ya) ″ = 0, is isomorphic to the Lie algebra
of the special linear group of order (n + 2), over the real numbers, sl(n + 2, ℝ). In this paper, we provide an alternate representation of the symmetry algebra by simple relabelling of indices. This provides one more proof of the result that the symmetry algebra of (ya) ″ = 0 is sl(n + 2, ℝ).