bluuebunny/crossref_metadata_2025 huggingface dataset:
A simple and effective noise whitening method for underwater acoustic orthogonal frequency division multiplexing
Authors: Berger Christian R. , Chen Weian , Zhou Shengli , Huang Jie
Published: April 2010

Underwater acoustic orthogonal frequency division multiplexing (OFDM) enables simple frequency domain equalization, but its performance is often limited by intercarrier interference (ICI) that is induced by channel variation, in addition to the ambient noise. As the signal itself, the variance of the ICI is frequency dependent as (i) the transmitter often has a nonideal transmit voltage response (TVR) and (ii) underwater acoustic propagation introduces frequency dependent attenuation. In this paper, a simple method to account for the frequency dependent spectrum of the ICI plus noise is proposed. Specifically, the power spectrum of the ICI plus noise is approximated using a low-order polynomial in the log domain, by fitting the measurements on the null subcarriers embedded in each OFDM symbol. Prewhitening is then applied to each OFDM symbol before channel estimation and data demodulation. The proposed method is tested using experimental data collected from the SPACE08 and RACE08 experiments, where signals with and without transmitter precompensation are compared side by side in the former. Impressive performance gains are found whenever the signal is significantly colored. This is the case when either the TVR is not compensated or the transmission distance and bandwidth are large.
Design and performance evaluation of a broadband three dimensional acoustic intensity measuring system
Authors: Miah Khalid H. , Hixon Elmer L.
Published: April 2010

A seven-microphone three dimensional (3D) intensity measuring system has been developed and evaluated for performance for a broad frequency band (200 Hz–6.5 kHz). Six microphones are arranged in a concentric array with one microphone at the center of the probe. The screw adjustable center microphone is the probe reference microphone, and is used for calibrations of the other microphones in the probe. This probe addresses limitations of the traditional two-microphone system in measuring acoustical properties in a 3D space from the one dimensional measurements. This probe also eliminates the need of spacers used in the existing 3D probes for broadband measurements. Diffraction and reflection effects on calibrations due to presence of the microphones and the probe supporting structure are negligible. This seven-microphone probe provided better results in the intensity measurements for the wide frequency band than that of a similar four-microphone array probe.
Phase and group velocity measurement of ultrasonic guided wavetrains in plates by pulsed TV holography
Authors: Deán-Ben X. Luís , Trillo Cristina , Doval Ángel F. , Fernández José L.
Published: April 2010

A method for the measurement of the phase and group velocities of guided acoustic waves is presented. For this purpose, a unique capability of a self-developed double-pulsed TV holography system to create movies of the propagation of guided acoustic wavetrains is used. Thereby, the experimental visualization of the evolution of Lamb and Rayleigh wavetrains in aluminum plates is shown, including several movies that illustrate different dispersive behaviors. Each movie shows the propagation of a narrowband wavetrain with a central frequency in the order of 1 MHz that consists of a carrier moving with the phase velocity, modulated by an envelope moving with the group velocity. Each snapshot is a two-dimensional map of the instantaneous out-of-plane displacement field of the surface points of the plate, with amplitudes in the order of several nanometers, acquired with the double-pulsed TV holography system. Then, by repeating the acquisition with successively increasing delays between the generation and detection instants, a sequence of maps is obtained from which a movie is composed. The phase and group velocities of the waves are accurately measured from the movies, yielding values that match well with the reference values for the same plates obtained from independent measurements.
Detecting Atlantic herring by parametric sonar
Authors: Godø Olav Rune , Foote Kenneth G. , Dybedal Johnny , Tenningen Eirik , Patel Ruben
Published: April 2010

The difference-frequency band of the Kongsberg TOPAS PS18 parametric sub-bottom profiling sonar, nominally 1–6 kHz, is being used to observe Atlantic herring. Representative TOPAS echograms of herring layers and schools observed in situ in December 2008 and November 2009 are presented. These agree well with echograms of volume backscattering strength derived simultaneously with the narrowband Simrad EK60/18- and 38-kHz scientific echo sounder, also giving insight into herring avoidance behavior in relation to survey vessel passage. Progress in rendering the TOPAS echograms quantitative is described.
Distortion product emissions from a cochlear model with nonlinear mechanoelectrical transduction in outer hair cells
Authors: Liu Yi-Wen , Neely Stephen T.
Published: April 2010

A model of cochlear mechanics is described in which force-producing outer hair cells (OHC) are embedded in a passive cochlear partition. The OHC mechanoelectrical transduction current is nonlinearly modulated by reticular-lamina (RL) motion, and the resulting change in OHC membrane voltage produces contraction between the RL and the basilar membrane (BM). Model parameters were chosen to produce a tonotopic map typical of a human cochlea. Time-domain simulations showed compressive BM displacement responses typical of mammalian cochleae. Distortion product (DP) otoacoustic emissions at 2f1−f2 are plotted as isolevel contours against primary levels (L1,L2) for various primary frequencies f1 and f2 (f1<f2). The L1 at which the DP reaches its maximum level increases as L2 increases, and the slope of the “optimal” linear path decreases as f2/f1 increases. When primary levels and f2 are fixed, DP level is band passed against f1. In the presence of a suppressor, DP level generally decreases as suppressor level increases and as suppressor frequency gets closer to f2; however, there are exceptions. These results, being similar to data from human ears, suggest that the model could be used for testing hypotheses regarding DP generation and propagation in human cochleae.
The role of formant amplitude in the perception of /i/ and /u/
Authors: Kiefte Michael , Enright Teresa , Marshall Lacey
Published: April 2010

Although recent evidence reconfirmed the importance of spectral peak frequencies in vowel identification [Kiefte and Kluender (2005). J. Acoust. Soc. Am. 117, 1395–1404], the role of formant amplitude in perception remains somewhat controversial. Although several studies have demonstrated a relationship between vowel perception and formant amplitude, this effect may be a result of basic auditory phenomena such as decreased local spectral contrast and simultaneous masking. This study examines the roles that local spectral contrast and simultaneous masking play in the relationship between the amplitude of spectral peaks and the perception of vowel stimuli. Both full- and incomplete-spectrum stimuli were used in an attempt to separate the effects of local spectral contrast and simultaneous masking. A second experiment was conducted to measure the detectability of the presence/absence of a formant peak to determine to what extent identification data could be predicted from spectral peak audibility alone. Results from both experiments indicate that, while both masking and spectral contrast likely play important roles in vowel perception, additional factors must be considered in order to account for vowel identification data. Systematic differences between the audibility of spectral peaks and predictions of perceived vowel identity were observed.
Judgments of intensity for brief sequences
Authors: Gallun Frederick J.
Published: April 2010

The ability to make intensity judgments for sequential stimuli was examined with an intensity-discrimination task involving three 50-ms noise bursts with non-overlapping frequency ranges. Targets (single bursts) presented in three-burst sequences were required to be as much as 5 dB more intense than targets presented as single bursts in isolation, especially for the later targets. Randomizing target position in the sequence did not reliably reduce performance, nor were thresholds for younger and older listeners reliably different. These increases in increment detection threshold are indications of a specific intensity-processing deficit for stimuli occurring later in a sequence.
Synchrony of Thalamocortical Inputs Maximizes Cortical Reliability
Authors: Wang Hsi-Ping , Spencer Donald , Fellous Jean-Marc , Sejnowski Terrence J.
Published: April 2010

Precise and Efficient Cortical Communication

How do thalamic neurons reliably transmit information to the cerebral cortex, despite making few synaptic connections onto their target neurons? Correlated input spikes from the thalamus have been reported, but the number of synchronous inputs and their precision and reliability is unclear.

Wang
et al.

(p.
106
) analyzed a unique data set of simultaneous thalamic and cortical recordings in vivo and compared them with simulations of a model cortical neuron. Using the recorded spike trains as inputs to the model, and constraining the model by the measured output spike trains, allowed strong predictions of the degree of convergence of synchronous inputs from the lateral geniculate nucleus. Synchrony, rather than the strength or frequency of synaptic inputs, was key to signaling, and the data suggest that there may be a region of optimal synchronous coding.
Dynamic Regulation of Archaeal Proteasome Gate Opening As Studied by TROSY NMR
Authors: Religa Tomasz L. , Sprangers Remco , Kay Lewis E.
Published: April 2010

Open Sesame

The proteosome plays a key role in cellular homeostasis through catalyzing protein degradation. It is a barrel-shaped nanomachine whose activity is regulated through gating substrate entry.

Religa
et al.

(p.
98
) now show that N-terminal gating residues in the proteasome interconvert on a second's time-scale between conformations that place them either outside or inside the proteasomal antechamber. An increase in the number of termini occupying the “in” state decreased rates of hydrolysis. Furthermore, proteasome activators known to increase the proteolysis rate lead to an increase in the number of termini in the “out” state.
Maize Tumors Caused by
Ustilago maydis
Require Organ-Specific Genes in Host and Pathogen
Authors: Skibbe David S. , Doehlemann Gunther , Fernandes John , Walbot Virginia
Published: April 2010

Tailor-Made Tumor

The biotrophic smut pathogen
Ustilago maydis
specifically infects the important crop plant, maize. The pathogen elicits large tumors on all aerial maize organs by redirecting primordia into a tumor pathway, and maize developmental mutants can disrupt tumor progression.

Skibbe
et al.

(p.
89
) examined gene expression in parallel in both the host plant and the smut pathogen and found that organ-specific gene expression patterns were required in both for tumor formation. Thus, fungal pathogens may exert distinct effects on different organs and tissues in plants, perhaps explaining the diverse pathologies that can be produced in diseased plants.
Mantle Flow Drives the Subsidence of Oceanic Plates
Authors: Adam Claudia , Vidal Valérie
Published: April 2010

Sinking Sea Floors

The depths of ocean bottoms are constantly fluctuating at a very slow rate in response to the generation (at mid-ocean ridges) and consumption (at subduction zones) of sea-floor material. Because older sea floor is susceptible to sinking as it cools, it has been assumed that sea-floor depth varies directly with its age. However,
Adam and Vidal
(p.
83
; see the Perspective by

Tolstoy

) now show that the depth of the Pacific Ocean actually varies in response to the mantle underlying the oceanic crust. This effect is clear when sea-floor depth was measured along lithospheric flow lines—which represent the movement of oceanic crust triggered by mantle convection. Because the ocean bottom does not flatten as predicted by previous models, there is no need to invoke any additional heat supply to sustain old oceanic crust in thermal models of the mantle.
China's Road to Sustainability
Authors: Liu Jianguo
Published: April 2010

Complex interactions of various forces create a bumpy road to environmental sustainability in China.
What Lies Beneath
Authors: Tolstoy Maya
Published: April 2010

Convection in Earth's hot mantle plays a key role in determining ocean depth.
Ocean Chemistry and Early Animals
Authors: Narbonne Guy M.
Published: April 2010

Chemical changes in the world's oceans were key to the early evolution of animals.
Thought Experiment Torpedoes Variable-Speed-of-Light Theories
Authors: Cho Adrian
Published: April 2010

Physicists' best chance of spotting an effect of "quantum gravity"—the melding of quantum mechanics and Einstein's theory of gravity—may have evaporated.
NOAA's Tom Karl Takes On Task of Serving Up Climate to the Public
Authors: Kerr Richard A.
Published: April 2010

Climatologist Thomas Karl, currently director of NOAA's National Climatic Data Center in Asheville, North Carolina, is the interim director of the new NOAA Climate Service. Karl spoke with
Science
on 18 March.
A Matter of Life and Limb
Authors: Cohen Jon
Published: April 2010

The chimpanzees at Kibale National Park in Uganda are not threatened by poachers for bushmeat. But they face another peril: Many become entangled in snares set in the forest for other animals such as duikers.
Boxed About the Ears, Ape Language Research Field Is Still Standing
Authors: Cohen Jon
Published: April 2010

A once-thriving field now has only a single outpost, the Great Ape Trust, which continues to teach bonobos and orangutans to communicate with humans.
The Inner Workings of the Chimpanzee Brain
Authors: Cohen Jon
Published: April 2010

Using a noninvasive magnetic resonance imaging scanner, investigators have launched a pathbreaking cerebral journey to probe everything from cognition to disease.
Stabilization of VEGFR2 Signaling by Cerebral Cavernous Malformation 3 Is Critical for Vascular Development
Authors: He Yun , Zhang Haifeng , Yu Luyang , Gunel Murat , Boggon Titus J. , Chen Hong , Min Wang
Published: April 2010

CCM3, which is associated with inherited cerebrovascular defects, prevents ligand-mediated degradation of a receptor involved in blood vessel formation.
Determining the Flow
Authors: Foley John F.
Published: April 2010

Planar cell polarity signaling and fluid flow regulate the orientation of cilia.
Bladder Relief?
Authors: Damani Samir
Published: April 2010

A genome-wide association study identifies a novel variant located near a previously known variant linked to low-grade recurrent bladder cancer.
Antibiotic Augmentation of Allografts
Authors: Ng Kenneth W.
Published: April 2010

A bone graft destined for transplantation can be coated with antibiotics, reducing adherent bacteria and thus the risk of infection to the recipient.
Inhibitory Effect of Biocides on the Viable Masses and Matrices of
Staphylococcus aureus
and
Pseudomonas aeruginosa
Biofilms
Authors: Toté K. , Horemans T. , Berghe D. Vanden , Maes L. , Cos P.
Published: April 2010

Bacteria and matrix are essential for the development of biofilms, and assays should therefore target both components. The current European guidelines for biocidal efficacy testing are not adequate for sessile microorganisms; hence, alternative discriminatory test protocols should be used. The activities of a broad range of biocides on
Staphylococcus aureus
and
Pseudomonas aeruginosa
biofilms were evaluated using such
in vitro
assays. Nearly all selected biocides showed a significant decrease in
S. aureus
biofilm viability, with sodium hypochlorite and peracetic acid as the most active biocides. Only hydrogen peroxide and sodium hypochlorite showed some inhibitory effect on the matrix. Treatment of
P. aeruginosa
biofilms was roughly comparable to that of
S. aureus
biofilms. Peracetic acid was the most active on viable mass within 1 min of contact. Isopropanol ensured a greater than 99.999% reduction of
P. aeruginosa
viability after at least 30 min of contact. Comparable to results with
S. aureus
, sodium hypochlorite and hydrogen peroxide markedly reduced the
P. aeruginosa
matrix. This study clearly demonstrated that despite their aspecific mechanisms of action, most biocides were active only against biofilm bacteria, leaving the matrix undisturbed. Only hydrogen peroxide and sodium hypochlorite were active on both the biofilm matrix and the viable mass, making them the better antibiofilm agents. In addition, this study emphasizes the need for updated and standardized guidelines for biofilm susceptibility testing of biocides.
Protein-Specific Analysis of Humoral Immune Responses in a Clinical Trial for Vaccines against Contagious Bovine Pleuropneumonia
Authors: Hamsten Carl , Tjipura-Zaire Georgina , McAuliffe Laura , Huebschle Otto J. B. , Scacchia Massimo , Ayling Roger D. , Persson Anja
Published: April 2010

Specific humoral immune responses in a clinical trial on cattle for vaccines against contagious bovine pleuropneumonia (CBPP) were investigated. The trial included a subunit vaccine consisting of five recombinant putative variable surface proteins of the infectious agentMycoplasma mycoidessubsp.mycoidessmall colony type (M. mycoidesSC) compared to the currently approved attenuated vaccine strain T1/44 and untreated controls. Humoral immune responses to 65 individual recombinant surface proteins ofM. mycoidesSC were monitored by a recently developed bead-based array assay. Responses to the subunit vaccine components were found to be weak. Animals vaccinated with this vaccine were not protected and had CBPP lesions similar to those of the untreated controls. In correlating protein-specific humoral responses to T1/44-induced immunity, five proteins associated with a protective immune response were identified by statistical evaluation, namely, MSC_1046 (LppQ), MSC_0271, MSC_0136, MSC_0079, and MSC_0431. These five proteins may be important candidates in the development of a novel subunit vaccine against CBPP.
Efficacy of a Potential Trivalent Vaccine Based on Hc Fragments of Botulinum Toxins A, B, and E Produced in a Cell-Free Expression System
Authors: Zichel R. , Mimran A. , Keren A. , Barnea A. , Steinberger-Levy I. , Marcus D. , Turgeman A. , Reuveny S.
Published: April 2010

Botulinum toxins produced by the anaerobic bacteriumClostridium botulinumare the most potent biological toxins in nature. Traditionally, people at risk are immunized with a formaldehyde-inactivated toxin complex. Second generation vaccines are based on the recombinant carboxy-terminal heavy-chain (Hc) fragment of the neurotoxin. However, the materialization of this approach is challenging, mainly due to the high AT content of clostridial genes. Herein, we present an alternative strategy in which the native genes encoding Hc proteins of botulinum toxins A, B, and E were used to express the recombinant Hc fragments in a cell-free expression system. We used the unique property of this open system to introduce different combinations of chaperone systems, protein disulfide isomerase (PDI), and reducing/oxidizing environments directly to the expression reaction. Optimized expression conditions led to increased production of soluble Hc protein, which was successfully scaled up using a continuous exchange (CE) cell-free system. Hc proteins were produced at a concentration of more than 1 mg/ml and purified by one-step Ni+affinity chromatography. Mice immunized with three injections containing 5 μg of any of thein vitro-expressed, alum-absorbed, Hc vaccines generated a serum enzyme-linked immunosorbent assay (ELISA) titer of 105against the native toxin complex, which enabled protection against a high-dose toxin challenge (103to 106mouse 50% lethal dose [MsLD50]). Finally, immunization with a trivalent HcA, HcB, and HcE vaccine protected mice against the corresponding trivalent 105MsLD50toxin challenge. Our results together with the latest developments in scalability of thein vitroprotein expression systems offer alternative routes for the preparation of botulinum vaccine.
Structural and Functional Characterization of an RNase HI Domain from the Bifunctional Protein Rv2228c from
Mycobacterium tuberculosis
Authors: Watkins Harriet A. , Baker Edward N.
Published: April 2010

The open reading frame Rv2228c from
Mycobacterium tuberculosis
is predicted to encode a protein composed of two domains, each with individual functions, annotated through sequence similarity searches. The N-terminal domain is homologous with prokaryotic and eukaryotic RNase H domains and the C-terminal domain with α-ribazole phosphatase (CobC). The N-terminal domain of Rv2228c (Rv2228c/N) and the full-length protein were expressed as fusions with maltose binding protein (MBP). Rv2228c/N was shown to have RNase H activity with a hybrid RNA/DNA substrate as well as double-stranded RNase activity. The full-length protein was shown to have additional CobC activity. The crystal structure of the MBP-Rv2228c/N fusion protein was solved by molecular replacement and refined at 2.25-Å resolution (
R
= 0.182;
R
free
= 0.238). The protein is monomeric in solution but associates in the crystal to form a dimer. The Rv2228c/N domain has the classic RNase H fold and catalytic machinery but lacks several surface features that play important roles in the cleavage of RNA/DNA hybrids by other RNases H. The absence of either the basic protrusion of some RNases H or the hybrid binding domain of others appears to be compensated by the C-terminal CobC domain in full-length Rv2228c. The double-stranded-RNase activity of Rv2228c/N contrasts with classical RNases H and is attributed to the absence in Rv2228c/N of a key phosphate binding pocket.
Streptococcus gallolyticusSubspeciespasteurianus(Biotype II/2), a Newly Reported Cause of Adult Meningitis
Authors: Sturt Amy S. , Yang Liying , Sandhu Kuldip , Pei Zhiheng , Cassai Nicholas , Blaser Martin J.
Published: April 2010

We report the first case of adult meningitis confirmed to be due toStreptococcus gallolyticussubsp.pasteurianus. Phenotypically reported asStreptococcus bovisbiotype II/2, 16S rRNA sequencing revealedS. gallolyticussubsp.pasteurianus. Because of taxonomic uncertainties,S. gallolyticussubsp.pasteurianusmay be an underrecognized agent of systemic infections.
Murine Coronavirus Delays Expression of a Subset of Interferon-Stimulated Genes
Authors: Rose Kristine M. , Elliott Ruth , Martínez-Sobrido Luis , García-Sastre Adolfo , Weiss Susan R.
Published: April 2010

The importance of the type I interferon (IFN-I) system in limiting coronavirus replication and dissemination has been unequivocally demonstrated by rapid lethality following infection of mice lacking the alpha/beta IFN (IFN-α/β) receptor with mouse hepatitis virus (MHV), a murine coronavirus. Interestingly, MHV has a cell-type-dependent ability to resist the antiviral effects of IFN-α/β. In primary bone-marrow-derived macrophages and mouse embryonic fibroblasts, MHV replication was significantly reduced by the IFN-α/β-induced antiviral state, whereas IFN treatment of cell lines (L2 and 293T) has only minor effects on replication (K. M. Rose and S. R. Weiss, Viruses 1:689-712, 2009). Replication of other RNA viruses, including Theiler's murine encephalitis virus (TMEV), vesicular stomatitis virus (VSV), Sindbis virus, Newcastle disease virus (NDV), and Sendai virus (SeV), was significantly inhibited in L2 cells treated with IFN-α/β, and MHV had the ability to rescue only SeV replication. We present evidence that MHV infection can delay interferon-stimulated gene (ISG) induction mediated by both SeV and IFN-β but only when MHV infection precedes SeV or IFN-β exposure. Curiously, we observed no block in the well-defined IFN-β signaling pathway that leads to STAT1-STAT2 phosphorylation and translocation to the nucleus in cultures infected with MHV. This observation suggests that MHV must inhibit an alternative IFN-induced pathway that is essential for early induction of ISGs. The ability of MHV to delay SeV-mediated ISG production may partially involve limiting the ability of IFN regulatory factor 3 (IRF-3) to function as a transcription factor. Transcription from an IRF-3-responsive promoter was partially inhibited by MHV; however, IRF-3 was transported to the nucleus and bound DNA in MHV-infected cells superinfected with SeV.
Japanese Encephalitis Virus Utilizes the Canonical Pathway To Activate NF-κB but It Utilizes the Type I Interferon Pathway To Induce Major Histocompatibility Complex Class I Expression in Mouse Embryonic Fibroblasts
Authors: Abraham Sojan , Nagaraj Ashwini Sankrepatna , Basak Soumen , Manjunath Ramanathapuram
Published: April 2010

Flaviviruses have been shown to induce cell surface expression of major histocompatibility complex class I (MHC-I) through the activation of NF-κB. Using IKK1
−/−
, IKK2
−/−
, NEMO
−/−
, and IKK1
−/−
IKK2
−/−
double mutant as well as p50
−/−
RelA
−/−
cRel
−/−
triple mutant mouse embryonic fibroblasts infected with Japanese encephalitis virus (JEV), we show that this flavivirus utilizes the canonical pathway to activate NF-κB in an IKK2- and NEMO-, but not IKK1-, dependent manner. NF-κB DNA binding activity induced upon virus infection was shown to be composed of RelA:p50 dimers in these fibroblasts. Type I interferon (IFN) production was significantly decreased but not completely abolished upon virus infection in cells defective in NF-κB activation. In contrast, induction of classical MHC-I (class 1a) genes and their cell surface expression remained unaffected in these NF-κB-defective cells. However, MHC-I induction was impaired in IFNAR
−/−
cells that lack the alpha/beta IFN receptor, indicating a dominant role of type I IFNs but not NF-κB for the induction of MHC-I molecules by Japanese encephalitis virus. Our further analysis revealed that the residual type I IFN signaling in NF-κB-deficient cells is sufficient to drive MHC-I gene expression upon virus infection in mouse embryonic fibroblasts. However, NF-κB could indirectly regulate MHC-I expression, since JEV-induced type I IFN expression was found to be critically dependent on it.
Whole-Genome Characterization and Genotyping of Global WU Polyomavirus Strains
Authors: Bialasiewicz Seweryn , Rockett Rebecca , Whiley David W. , Abed Yacine , Allander Tobias , Binks Michael , Boivin Guy , Cheng Allen C. , Chung Ju-Young , Ferguson Patricia E. , Gilroy Nicole M. , Leach Amanda J. , Lindau Cecilia , Rossen John W. , Sorrell Tania C. , Nissen Michael D. , Sloots Theo P.
Published: April 2010

Exploration of the genetic diversity of WU polyomavirus (WUV) has been limited in terms of the specimen numbers and particularly the sizes of the genomic fragments analyzed. Using whole-genome sequencing of 48 WUV strains collected in four continents over a 5-year period and 16 publicly available whole-genome sequences, we identified three main WUV clades and five subtypes, provisionally termed Ia, Ib, Ic, II, IIIa, and IIIb. Overall nucleotide variation was low (0 to 1.2%). The discriminatory power of the previous VP2 fragment typing method was found to be limited, and a new, larger genotyping region within the VP2/1 interface was proposed.
Modelling capacity of transparent soil
Authors: Liu Jinyuan , Iskander Magued G.
Published: April 2010

The modelling capacity of transparent soil was investigated by comparing boundary soil displacement fields under a model footing in a transparent soil model with those from a natural soil model. Transparent soil is made of either amorphous silica gels or powders and a pore fluid with a matching refractive index to model sand and clay. An optical system consisting of a laser light, camera, frame grabber, and computer was developed to optically slice a transparent soil model. A distinctive laser speckle pattern was generated by the interaction between the laser light and transparent soil. Two laser speckle images before and after a deformation were used to calculate the displacement field using an image processing technique called digital image correlation. The comparative study shows that transparent soil can be used to study natural soil with some limitations. Transparent soil and the developed optical system could be used to explore opportunities for more advanced nonintrusive three-dimensional deformation measurements for various soil–structure interaction problems.
CONSTRAINTS ON VARIABLE CHAPLYGIN GAS MODEL FROM TYPE IA SUPERNOVAE AND BARYON ACOUSTIC OSCILLATIONS
Authors: LU JIANBO , XU LIXIN
Published: April 2010

We apply the type Ia supernovae union dataset and the baryon acoustic oscillations data at z = 0.2 and z = 0.35 to constrain variable Chaplygin gas (VCG) model as the unification of dark matter and dark energy. It is shown that the confidence levels for VCG model parameters are [Formula: see text]. And it indicates that the values of transition redshift and current deceleration parameter are: [Formula: see text]. In addition, we plot the evolution trajectory of the VCG model in the statefinder parameter r–s plane and show the discrimination between this scenario and other dark energy models.
HIGHER ORDER THERMOELASTIC PROPERTIES OF THE EARTH LOWER MANTLE AND CORE
Authors: KUSHWAH S. S. , BHARDWAJ N. K.
Published: April 2010

We have used some of the most reliable high pressure equations of state (EOS) to determine the thermoelastic Grüneisen parameter and its higher order volume derivatives for the lower mantle, outer core and inner core of the Earth. The cross derivatives of bulk modulus with respect to pressure and temperature have also been obtained for the deep interior of the Earth using the results based on the modified free volume theory for the Grüneisen parameter. We have used five EOS viz. (a) modified Rydberg EOS, (b) modified Poirier–Tarantola EOS, (c) Hama–Suito EOS, (d) Stacey EOS, and (e) Kushwah EOS to determine pressure derivatives of bulk modulus. The results for thermoelastic parameters obtained in the present study show systematic variations with the increase in pressure.
HYPERCHAOTIC SYNCHRONIZATION
Authors: VIDAL GERARD , MANCINI HÉCTOR
Published: April 2010

In this work we study the synchronization between identical pairs of hyperchaotic mathematical systems symmetrically coupled. Calculations are performed firstly in two well-known hyperchaotic systems, and then compared with the results obtained coupling symmetrically two Takens–Bogdanov systems (TBS) which represent a bifurcation in Codimension 2 (a point with two modes bifurcating simultaneously). In all of these systems, complete synchronization is achieved for some intervals of the coupling strength. As it will be shown, these windows can be localized by using the representation of the Lyapounov exponents against the coupling parameter. We analyze here these three models looking for general features in synchronization of hypercaotic systems, that could be useful to model mutual synchronization of two time-dependent convection experiments. We plan to use the results obtained in the TBS as a direct guide to control our experiment because this model was successfully used before to represent the observed dynamics. The other two systems presented here (Chen and Lü) are used to look for the possibility of general features and to check the used numerical methods.
ACCURATE INTERACTIVE ANIMATION OF DEFORMABLE MODELS AT ARBITRARY RESOLUTION
Authors: NESME MATTHIEU , FAURE FRANÇOIS , PAYAN YOHAN
Published: April 2010

Providing realistic interactive simulation requires a powerful animation method with a highly detailed rendering. Based on continuum mechanics, the finite element method needs a volumetric representation of the object to animate. This paper proposes an automatic method for building meshes that are well adapted to interactive simulation starting from miscellaneous input data. Contrary to commonly used methods based on tetrahedral volume meshing, the object is embedded in a regular grid of deformable hexahedra at an arbitrary resolution. This alleviates the complexities and limitations of tetrahedra and results in regular, well-conditioned meshes. Mass and stiffness are set in order to model the physical properties as accurately as possible at any given resolution, in a manner that takes into account the distribution of material within the hexahedra. This allows us to accurately model the mechanical properties of the partially empty boundary hexahedra, and thus enables us to perform fast simulation at a coarse resolution. The accuracy of this approach is compared to theoretical results. In addition, we extend a fast and robust co-rotational approach to the case of hexahedral elements. This permits simulation of arbitrarily complex shapes at interactive rates. We show how to build the hexahedra directly from surfaces and from segmented scanned data, which is very useful to animate complex artistic models or patient specific models for individual medical simulation. Finally, we show how a fast volumetric rendering can make efficient use of the grid structure.
FUZZY GROUP DECISION MAKING IN PURSUIT OF A COMPETITIVE MARKETING STRATEGY
Authors: LIN CHIN-TSAI , LEE CHUAN , WU CHENG-SHIUNG
Published: April 2010

To determine marketing strategy may well be the most critical function of management. The pursuit of competitive advantage always requires much deliberate thought and discussion. The current study attempts to develop a marketing strategy evaluation framework based on the resource-based view (RBV) of the firm to competitive advantage. It tries to identify the most important marketing-specific resources and capabilities using a multiple criteria decision making (MCDM) method. This study employs the fuzzy analytic hierarchy process (AHP) method as an analytical tool to determine a unique competitive marketing strategy for a small tourism venture such as a privately owned hotel. The findings indicate that the differentiation strategy is the best competitive marketing strategy for allocating specific and limited resources and capabilities toward sustainable competitive advantage.
GABOR-BASED TENSOR LOCAL DISCRIMINANT EMBEDDING AND ITS APPLICATION ON PALMPRINT RECOGNITION
Authors: CUI LIMIN , WEI YANTAO , TANG YUAN YAN , LI HONG
Published: April 2010

In this paper, a novel feature extraction method called Gabor-based tensor local discriminant embedding (GTLDE) is proposed. GTLDE first gets the high-order statistic information by using a biologically inspired hierarchical model, and then tensor local discriminant embedding (TLDE) is carried out to extract the discriminant features of the image for recognition task. The method we proposed is not only robust to local translation and scale variations, but also has high distinguishing ability. More importantly, our method can achieve high accuracy with a small number of training samples. Experimental results on PolyU-II palmprint database demonstrate the effectiveness of the method we proposed.
Contrasting fluid events giving rise to apparently similar diagenetic products; late-stage dolomite cements from the Southern Alps and central Apennines, Italy
Authors: Ronchi P. , Giulio A. Di , Ceriani A. , Scotti P.
Published: April 2010

Precipitation of dolomite cements in Jurassic carbonate platform sediments and slope breccias has been studied from well cores and outcrops of the central Southern Alps and central Apennines in Italy.

In both areas, an initial, massive dolomite replacement was followed by multiphase precipitation of dolomite cements. The replacement occurred during burial, in a passive margin regime, in response to compaction-driven flow of formational fluids. This interpretation is based on results from fluid inclusion and stable isotope analyses which have been related to the thermal history. The dolomite cements precipitated when both areas were involved in collisional tectonics. In spite of the similar diagenetic evolution, the fluids causing dolomite cementation in each case were compositionally different. In the Alps a decrease in salinity was recorded from sea water to brackish fluids, whereas in the Apennines an increase in salinity from sea water up to >10% NaCl equivalent was recorded. The remarkable salinity differences in diagenetic fluids are considered to be related to the different sub-aerial relief of the two belts during dolomite precipitation. In the Alps, the dilution of fluids is related to the infiltration of meteoric waters from the mountain chain, that was widely emergent. In the Apennines, dolomite cements precipitated whilst the structural units were still widely submerged, preventing meteoric dilution of cementing fluids and promoting an increase in salinity through mixing with fluids rising from older evaporate-bearing layers. In both Alpine and Apennine cases, the same diagenetic trend is observed in thrust-fold belt and foreland basin units; in both structural systems the diagenetic events start precipitating dolomite cements in the inner part of the collision zone and then the diagenetic processes migrate towards the foreland basin along with the structural evolution of the area.
Sedimentary evolution of an Upper Jurassic epeiric carbonate ramp, Iberian Basin, NE Spain
Authors: Aurell M. , Bádenas B. , Ipas J. , Ramajo J.
Published: April 2010

A synthesis of the sedimentary evolution of the Upper Jurassic carbonate epeiric ramps that developed in the northern part of the Iberian Basin (NE Spain) is presented. The facies distributions reconstructed from the analysis of a 200 km-long transect, show a transition from shallow to relatively deep sedimentation sites. The studied carbonate ramps record major long-term transgression, from mid-Oxfordian to mid-Kimmeridgian followed by progressive basinwards coastal shift until the major regressive event around the mid-Berriasian. Subsidence was relatively homogeneous across the northern Iberian Basin during most of the studied interval. Major episodes of differential subsidence occurred around the Oxfordian–Kimmeridgian transition and onwards from the mid-Tithonian.

The sedimentary evolution and particular facies types of the successive Iberian carbonate ramps is described, considering five depositional sequences that have a long-term transgressive-regressive evolution. The Oxfordian sequence shows a sharp transition from shallow to deep ramp areas: from mixed siliciclastic-carbonate (ooidal, skeletal, peloidal) facies to condensed (i.e. spongiolithic, peloidal, glauconitic) facies in the open platform domain. In the two Kimmeridgian sequences (Kim1 and Kim2), the transition between shallow and deep areas is more gradual and thickness distribution across the ramp is more homogeneous. Coral-microbial reefs and oolitic-peloidal-skeletal shoals characterized the shallow areas. Towards the offshore domain, these facies grade rapidly to a tempestite-dominated lithofacies and then into thick lime mudstone successions (i.e. rhythmic marls-mudstone alternations). Shallow oncolitic-peloidal and skeletal facies covered wide areas of the carbonate ramp during the early Tithonian (Ti1 sequence) and graded basinwards to thick successions of well-bedded micrites. The middle Tithonian to lower Berriasian platform (Ti2 sequence) is only partly exposed and formed during a stage of more heterogeneous subsidence. It is characterized by a thick succession with metre-scale shallowing-upward sequences with local development of peritidal, algal-laminated caps. The factors that controlled the sedimentary evolution and major facies changes across the successive epeiric carbonate ramps are discussed by comparison to other Upper Jurassic platforms developed in the western Tethyan realm.
Partitioning planar graphs with costs and weights
Authors: Aleksandrov Lyudmil , Djidjev Hristo , Guo Hua , Maheshwari Anil
Published: April 2010

A graph separator is a set of vertices or edges whose removal divides an input graph into components of bounded size. This paper describes new algorithms for computing separators in planar graphs as well as techniques that can be used to speed up the implementation of graph partitioning algorithms and improve the partition quality. In particular, we consider planar graphs with costs and weights on the vertices, where weights are used to estimate the sizes of the partitions and costs are used to estimate the size of the separator. We show that in these graphs one can always find a small cost separator (consisting of vertices or edges) that partitions the graph into components of bounded weight. We describe implementations of the partitioning algorithms and discuss results of our experiments.
GRASP with path relinking for the weighted MAXSAT problem
Authors: Festa Paola , Pardalos Panos M. , Pitsoulis Leonidas S. , Resende Mauricio G. C.
Published: April 2010

A GRASP with path relinking for finding good-quality solutions of the weighted maximum satisfiability problem (MAX-SAT) is described in this paper. GRASP, or Greedy Randomized Adaptive Search Procedure, is a randomized multistart metaheuristic, where, at each iteration, locally optimal solutions are constructed, each independent of the others. Previous experimental results indicate its effectiveness for solving weighted MAX-SAT instances. Path relinking is a procedure used to intensify the search around good-quality isolated solutions that have been produced by the GRASP heuristic. Experimental comparison of the pure GRASP (without path relinking) and the GRASP with path relinking illustrates the effectiveness of path relinking in decreasing the average time needed to find a good-quality solution for the weighted maximum satisfiability problem.
Implementing minimum cycle basis algorithms
Authors: Mehlhorn Kurt , Michail Dimitrios
Published: April 2010

In this paper, we consider the problem of computing a minimum cycle basis of an undirected graph
G
= (
V
,
E
) with
n
vertices and
m
edges. We describe an efficient implementation of an
O
(
m
3
+
mn
2
log
n
) algorithm. For sparse graphs, this is the currently best-known algorithm. This algorithm's running time can be partitioned into two parts with time
O
(
m
3
) and
O
(
m
2
n
+
mn
2
log
n
), respectively. Our experimental findings imply that for random graphs the true bottleneck of a sophisticated implementation is the
O
(
m
2
n
+
mn
2
log
n
) part. A straightforward implementation would require Ω(
nm
) shortest-path computations. Thus, we develop several heuristics in order to get a practical algorithm. Our experiments show that in random graphs our techniques result in a significant speed-up. Based on our experimental observations, we combine the two fundamentally different approaches to compute a minimum cycle basis to obtain a new hybrid algorithm with running time
O
(
m
2
n
2
). The hybrid algorithm is very efficient, in practice, for random dense unweighted graphs. Finally, we compare these two algorithms with a number of previous implementations for finding a minimum cycle basis of an undirected graph.
Implementing the LZ-index
Authors: Navarro Gonzalo
Published: April 2010

The LZ-index is a theoretical proposal of a lightweight data structure for text indexing, based on the Ziv-Lempel trie. If a text of
u
characters over an alphabet of size σ is compressible to
n
symbols using the LZ78 algorithm, then the LZ-index takes 4
n
log
2
n
(1+
o
(1)) bits of space (that is, 4 times the entropy of the text) and reports the
R
occurrences of a pattern of length m in worst case time
O
(
m
3
log σ + (
m
+
R
)log
n
). In this paper we face the challenge of obtaining a practical implementation of the LZ-index, which is not at all straightforward from the theoretical proposal. We end up with a prototype that takes the promised space and has average search time
O
(σ
m
log
u
+ √
uR
). This prototype is shown to be faster than other competing approaches when we take into account the time to report the positions or text contexts of the occurrences found. We show in detail the process of implementing the index, which involves interesting lessons of theory versus practice.
Computing visibility on terrains in external memory
Authors: Haverkort Herman , Toma Laura , Zhuang Yi
Published: April 2010

Given an arbitrary viewpoint
v
and a terrain, the visibility map or viewshed of
v
is the set of points in the terrain that are visible from
v
. In this article we consider the problem of computing the viewshed of a point on a very large grid terrain in external memory. We describe algorithms for this problem in the cache-aware and cache-oblivious models, together with an implementation and an experimental evaluation. Our algorithms are a novel application of the distribution sweeping technique and use
O
(
sort
(
n
)) I/Os, where
sort
(
n
) is the complexity of sorting
n
items of data in the I/O-model. The experimental results demonstrate that our algorithm scales up and performs significantly better than the traditional internal-memory plane sweep algorithm and can compute visibility for terrains of 1.1 billion points in less than 4 hours on a low-cost machine compared to more than 32 hours with the internal-memory algorithm.
Compressed text indexes
Authors: Ferragina Paolo , González Rodrigo , Navarro Gonzalo , Venturini Rossano
Published: April 2010

A
compressed full-text self-index
represents a text in a compressed form and still answers queries efficiently. This represents a significant advancement over the (full-)text indexing techniques of the previous decade, whose indexes required several times the size of the text. Although it is relatively new, this algorithmic technology has matured up to a point where theoretical research is giving way to practical developments. Nonetheless this requires significant programming skills, a deep engineering effort, and a strong algorithmic background to dig into the research results. To date only isolated implementations and focused comparisons of compressed indexes have been reported, and they missed a common API, which prevented their re-use or deployment within other applications.

The goal of this article is to fill this gap. First, we present the existing implementations of compressed indexes from a practitioner's point of view. Second, we introduce the
Pizza&Chili
site, which offers tuned implementations and a standardized API for the most successful compressed full-text self-indexes, together with effective test-beds and scripts for their automatic validation and test. Third, we show the results of our extensive experiments on these codes with the aim of demonstrating the practical relevance of this novel algorithmic technology.
An improved heuristic for computing short integral cycle bases
Authors: Kavitha Telikepalli , Krishna Katakam Vamsi
Published: April 2010

In this article, we consider the problem of constructing low-weight integral cycle bases in a directed graph
G
= (
V
,
E
) with nonnegative edge weights. It has been shown that low-weight integral cycle bases have applications in the periodic event scheduling problem and cyclic time tabling. However, no polynomial time algorithm is known for computing a minimum weight integral cycle basis in a given directed graph.

We give a necessary condition that has to be satisfied by any minimum weight integral cycle basis and guided by this necessary condition, we propose a new heuristic for constructing a low weight integral cycle basis. To the best of our knowledge, this is the first algorithm to construct integral cycle bases that are not necessarily fundamental. We implemented our heuristic and tested it on random graphs and compared the weight of the integral cycle basis computed by our algorithm with the weight of a minimum cycle basis and the weights of integral cycle bases (these are, in fact, fundamental cycle bases) computed by already existing and new heuristics for this problem. Empirical results suggest that our heuristic performs better than the existing heuristics for this problem and in fact, it computes a
minimum
weight integral cycle basis on these graphs. (In the above comparison, when the weight of the integral cycle basis computed and the weight of a minimum cycle basis turn out to be equal, it immediately implies that we have in fact found a minimum integral cycle basis.) The time needed for our heuristic is typically a little higher compared to the time taken by the other heuristics that compute fundamental cycle bases.