bluuebunny/crossref_metadata_2025 huggingface dataset:
Monotone Descent Path Queries on Dynamic Terrains
Authors: Wei Xiangzhi , Joneja Ajay , Tian Yaobin , Yao Yan-An
Published: October 2013

Monotone paths are useful in many engineering design applications. In this paper, we address the problem of answering monotone descent path queries on terrains that are continually changing. A terrain can be represented by a unique contour tree. Such a contour tree belongs to a class of graphs called arbitrarily directed trees (ADTs). Let T be an ADT with n nodes. In this paper, we present a new linear time preprocessing algorithm for decomposing a static ADT T into a forest F, with which we can answer lowest common descendent (LCA) queries in O(1) time. This is useful in answering monotone path queries on the corresponding terrain. We show how to maintain this data structure, and thereby answer LCA queries efficiently, for dynamic ADTs. We also show how to maintain the data structure of dynamic terrains, while simultaneously maintaining the corresponding contour tree. This allows us to efficiently answer monotone path queries between any two points on dynamic terrains.
Optimal Uncertainty Quantification: Distributional Robustness Versus Bayesian Brittleness
Authors: Sullivan T. J. , McKerns M. , Ortiz M. , Owhadi H. , Scovel C.
Published: October 2013

We discuss recent mathematical and computational results on uncertainty quantification (UQ) in the presence of uncertainty about the correct probabilistic and physical models. Such UQ problems can be formulated as constrained optimization problems with information acting as the constraints, with consequent optimal assessments of risk, and advantages for interdisciplinary communication and open science. We also report consequences of this point of view for the robustness of Bayesian methods under prior perturbation.
Flow-Excited Acoustic Resonance Excitation Mechanism, Design Guidelines, and Counter Measures
Authors: Ziada Samir , Lafon Philippe
Published: October 2013

The excitation mechanism of acoustic resonances has long been recognized, but the industry continues to be plagued by its undesirable consequences, manifested in severe vibration and noise problems in a wide range of industrial applications. This paper focuses on the nature of the excitation mechanism of acoustic resonances in piping systems containing impinging shear flows, such as flow over shallow and deep cavities. Since this feedback mechanism is caused by the coupling between acoustic resonators and shear flow instabilities, attention is focused first on the nature of various types of acoustic resonance modes and then on the aeroacoustic sound sources, which result from the interaction of the inherently unstable shear flow with the sound field generated by the resonant acoustic modes. Various flow-sound interaction patterns are discussed, in which the resonant sound field can be predominantly parallel or normal to the mean flow direction and the acoustic wavelength can be an order of magnitude longer than the length scale of the separated shear flow or as short as the cavity length scale. Since the state of knowledge in this field has been recently reviewed by Tonon et al. (2011, “Aeroacoustics of Pipe Systems With Closed Branches”, Int. J. Aeroacoust., 10(2), pp. 201–276), this article focuses on the more practical aspects of the phenomenon, including various flow-sound interaction patterns and the resulting aeroacoustic sources, which are relevant to industrial applications. A general design guide proposal and practical means to alleviate the excitation mechanism are also presented. These are demonstrated by two examples of recent industrial case histories dealing with acoustic fatigue failure of the steam dryer in a boiling water reactor (BWR) due to acoustic resonance in the main steam piping and acoustic resonances in the roll posts of the Short Take-Off and Vertical Lift Joint Strike Fighter (JSF).
Development of a Real-Time NOx Prediction Model Based on Heat Release Analysis in a Direct-Injection Diesel Engine
Authors: Wang Dong , Zhang Chao
Published: October 2013

A prediction model, which describes linear relationship between the nitrogen oxides (NOx) emissions and the in-cylinder heat release rate in a direct-injection diesel engine, was developed through numerical simulations. A modified KIVA-3 V code was used to calculate NOx formations and to conduct heat release analyses in a direct-injection diesel engine under different operating conditions. The numerical simulation results indicated that the NOx formation amount was related to both the magnitude and the timing of the peak heat release rate in each engine cycle. Based on the above observations, a control-oriented dynamic NOx model was constructed and then implemented into a feedback emission control system on a small diesel engine. A new parameter—combustion acceleration—was proposed in this research to describe the intensity of the premixed combustion. Experimental work was also conducted to measure the real-time in-cylinder pressure at each crank-angle when the engine was running and the heat release rate was calculated instantaneously to control an exhaust gas recirculation (EGR) valve. The experimental results showed that the proposed NOx prediction model was effective in controlling NOx emissions under high rpm conditions.
Contrast enhancement of vowels in Modern Standard German
Authors: Coren Amy E. , Heckmann Cheryl L.
Published: October 2013

In an earlier cross-language study of vowels in and out of utterance focus [Hay et al., J. Acoust. Soc. Am. 111, 2367 (2002)], it was reported that languages tend to make differential use of three possible means of contrast enhancement: an enlarged vowel space, greater use of vowel inherent spectral change (VISC), and greater systematic variation in duration across vowel categories. In the current study, these same means of vowel contrast enhancement were examined in Modern Standard German. Relative to speakers of American English, German speakers make less use of VISC and greater use of durational variation to enhance vowel distinctions. It appears that phonological properties of a language (e.g., the use of phonemic vowel length differences) are predictive of the particular means used by the language to enhance vowel contrasts in the utterance focus. [Work supported by NIDCD.]
Musical noise reduction using an adaptive filter
Authors: Hanada Takeshi , Murakami Takahiro , Ishida Yoshihisa , Hoya Tetsuya
Published: October 2013

This paper presents a method for reducing a particular noise (musical noise). The musical noise is artificially produced by Spectral Subtraction (SS), which is one of the most conventional methods for speech enhancement. The musical noise is the tin-like sound and annoying in human auditory. We know that the duration of the musical noise is considerably short in comparison with that of speech, and that the frequency components of the musical noise are random and isolated. In the ordinary SS-based methods, the musical noise is removed by the post-processing. However, the output of the ordinary post-processing is delayed since the post-processing uses the succeeding frames. In order to improve this problem, we propose a novel method using an adaptive filter. In the proposed system, the observed noisy signal is used as the input signal to the adaptive filter and the output of SS is used as the reference signal. In this paper we exploit the normalized LMS (Least Mean Square) algorithm for the adaptive filter. Simulation results show that the proposed method has improved the intelligibility of the enhanced speech in comparison with the conventional method.
The sounds of a murder
Authors: Peppin Richard J.
Published: October 2013

Often engineers and lawyers cannot communicate, in spite of repeated attempts. The lawyer has an idea and wants the engineer to prove it in front of a jury. As examples: a quiet, or briefly loud source must be shown to cause hearing damage, or a construction project in a backyard must be shown to be nonannoying. Often it is a no brainer, either way. But the testimony must be given! In this paper, I discuss a sad case. A young woman and her baby daughter were murdered. A witness claimed she heard something in the dead of night. If so, it was further evidence of guilt of the accused. If not, it was evidence of the lack of credibility of the witness and helped show innocence. I present the results of a forensic investigation of a very brutal murder based on acoustics of the victims’ screams, the structure housing the murder, and the witness. The results of the investigation attempted to help the case.
The application of m-sequences to bi-static active sonar
Authors: DeFerrari Harry A.
Published: October 2013

The m-sequences are ideal pulse compression signals that combine the energy of CW with the resolution of a pulse. Successful applications include numerous acoustic propagation experiments and the Global Positioning System. Yet, early attempts (circa 1960) to apply m-sequences to mono-static active sonar were unsuccessful. Through the years, Birdsall, Metzger and others have developed a body of theory, numerical methods and at-sea demonstrations that establish the feasibility of a novel bi-static approach—one that holds promise in high reverberation shallow water environs. An analysis is presented here. The approach includes (1) continuous transmission of long m-sequences; (2) synchronous sampling to form a CON (Complete Ortho-Normal) data set; (3) direct blast removal by HCCO (Hyperspace Cancellation by Coordinate Zeroing); and (4) a full range waveform Doppler search. Ultra-fast Hadamard Transforms speed up the direct waveform pulse m-sequence pulse compression and the inverse pulse waveform transform and thereby allow timely execution of the intensive computational burden. The result is a demonstrable approach that produces a gain of 30 dB over a simple pulse and 10 dB over other sonar signals. In the end, the approach requires continuous transmission and reception as opposed to ping and listen an awkward concept at first.
Cavitation in shock wave lithotripsy
Authors: Bailey Michael R. , Crum Lawrence A. , Sapozhnikov Oleg A. , Evan Andrew P. , McAteer James A. , Colonius Tim , Cleveland Robin O.
Published: October 2013

A case is presented for the important role of cavitation in stone comminution and tissue injury in shock wave lithotripsy (SWL). Confocal hydrophones and a coincidence algorithm were used to detect cavitation in kidney parenchyma. Elevated hydrostatic pressure dissolved cavitation nuclei and suppressed cell injury and stone comminution in vitro. A low-insertion-loss, thin, mylar film nearly eliminated stone erosion and crack formation only when in direct contact with the stone. This result indicates not only that cavitation is important in both cracking and erosion but also that bubbles act at the surface. Time inversion of the shock wave by use of a pressure-release reflector reduced the calculated pressure at bubble collapse and the measured depth of bubble-induced pits in aluminum. Correspondingly tissue injury in vivo was nearly eliminated. Cavitation was localized and intensified by the use of synchronously triggered, facing lithotripters. This dual pulse lithotripter enhanced comminution at its focus and reduced lysis in surrounding blood samples. The enhancement of comminution was lost when stones were placed in glycerol, which retarded bubble implosion. Thus, cavitation is important in comminution and injury and can be controlled to optimize efficacy and safety. [Work supported by NIH DK43381, DK55674, and FIRCA.]
Differential and gradient microphone arrays
Authors: Elko Gary W. , West James E. , Thompson Steve
Published: October 2013

Differential microphone arrays have been in existence for more than 7 decades and are the basis of most commercial directional microphones in use today. These microphones obtain directionality by combining the acoustic pressure and the pressure-difference to form what is termed a first-order differential microphone. Differential microphones are inherently superdirectional since they can obtain broadband directional gains of up to 6.0 dB in an array that is physically much smaller than the acoustic wavelength. Differential arrays constructed by subtracting omnidirectional microphones are inherently more flexible in that the directional response can be easily and continuously varied from omnidirectional to hypercardioid. The simultaneous measurement of the acoustic pressure and particle velocity allows one to estimate the complex acoustic intensity along the axis of a microphone pair. A measure of the complex acoustic intensity vector can be obtained using a minimum of four pressure-sensing microphones. Higher-order differential microphones are also possible by using more microphone elements, but the problems of microphone calibration and signal-to-noise combine to practically realize microphones of differential order greater than third order. We will present some of the history of differential microphone array design and discuss some applications related to hands-free communication, hearing aids, and spatial audio recording.
Evaluation and prediction of noise pollution levels in urban areas of Cdiz (Spain)
Authors: Rivas Silvia , Hernandez Ricardo , Cueto Jose Luis
Published: October 2013

In the European policy, one of the most important objectives is to achieve a high level of health and environmental protection. The latest studies have shown that more than 20% of the world population lives under unacceptable noise levels and near 60% of the European population is exposed to worrying noise levels during the day. So, nowadays one of the objectives to be pursued is the protection against noise, one of the main environmental problems in Europe. During the last 10 years different studies have been carried out in urban areas of Cdiz, in order to evaluate the noise pollution level and its management. Those studies exposed how the continuous development of legal device, more capable each time, might moderate the upper emission levels. Instead of it, the share of the medium levels of the population hold up and could be detrimental for its normal development, increasing progressively. It will be useful to develop more studies in this area, as we are doing in El Campo de Gibraltar to study those damaging levels and to predict their tendency, in order to establish and improve new methods of environmental noise protection.
Emergence of the time domain Green’s function from ocean noise correlations
Authors: Sabra Karim G. , Roux Philippe , Kuperman W. A. , Hodgkiss W. S. , Song Hee Chun , Akal T. , Stevenson Mark
Published: October 2013

The time domain Green’s function (TDGF) between two receivers can be extracted from the time-averaged correlation of synchronized recordings of ocean noise [Roux et al., J. Acoust. Soc. Am. 113, 2218 (2003)]. The deterministic TDGF appears through spatial and temporal integration over the distributed random noise sources in the ocean and corresponds to the correlation of random noise passing through both receivers. We will present an analysis of the convergence time of this correlation process based on ultrasonic noise and high frequency ocean noise recordings. We will investigate how, for a given environment, the emergence of the TDGF depends on (1) the spatial and temporal noise distribution, (2) the correlation window length, and (3) the frequency bandwidth.
Mid- to high-frequency ambient noise anisotropy and notch-filling mechanisms
Authors: Ferat Patrick A. , Arvelo Juan I.
Published: October 2013

Mid- to high-frequency noise (>3 kHz) is dominated by sub-surface bubble breaking caused by wind-driven wave action. For a submerged receiver in a downward-refracting environment, a noise notch centered about the horizontal is predicted in the vertical noise directionality. The noise notch width is related to the ratio of the sound speed at the receiver to the sound speed at the surface. The noise notch depth is determined by other noise filling mechanisms. For receiver arrays with vertical beamwidths sufficiently narrow to look in the notch, the characterization of the notch level is important for the prediction of beam noise levels near the horizontal. Three notch-filling mechanisms are described: down-slope conversion of surface energy due to bathymetry, volume scattering from volume inhomogeneities, and internal waves. A ray-based noise model is used to examine these mechanisms, as well as the sensitivity to uncertainty in environmental inputs.
The influence of pipe scaling parameters on the sound of flue organ pipes
Authors: Angster Judit M. , Wik Tilo , Taesch Christian , Sakamoto Yumiko , Miklos Andras
Published: October 2013

When basic phenomena of the physics of flue organ pipes is studied, experiments on models are acceptable. But these models often differ considerably from real organ pipes. For this reason the fine details of pipe sounds should be investigated on real pipes. The sound quality of an organ pipe is mainly influenced by the attack transients. This onset is first dominated by the edge tone, while later the pipe resonator will play a more important role. To understand the physics of a flue organ pipe it is necessary to measure the acoustic properties of the pipe resonator to analyze the edge tone, the attack transient, and the stationary sound of the pipe. Several special pipes with the same pitch have been investigated: pipes with different diameters; a pipe of which the cut up and a pipe of which the length is adjustable. By the evaluation all physical effects contributing to the production of sound were taken into account. The results together with the results of subjective listening tests will be used for developing a scaling method for dimensioning labial organ pipes and a software for designing organ pipe dimensions of the most important ranks. [Work supported by the European Commission.]
Can context diminish the effects of rapid speech recognition in older listeners?
Authors: Furukawa Izumi , Vaughan Nancy , Storzbach Daniel
Published: October 2013

This is a part of a larger study investigating the effects of cognitive slowing on speech perception among older adults. In addition to neurocognitive tests (working memory, attention, and speed of processing), time-compressed speech was used to evaluate the effects of age on rapid speech recognition. Two different speech materials (with and without contextual cues) were prerecorded and time-compressed to four different rates (40%, 50%, 60%, 65%) in order to increase the demand on processing speed. All sentences were presented monaurally through MedRx Otowizard via ER3 insert phones to older adults (50 to 75 year olds) with normal hearing and with mild to moderated hearing loss. For the listeners with hearing loss, the master hearing aid function with NAL-NP target was used. At the slower time-compression rate (40%), there was no significant difference between the two groups. However, at faster rates, the hearing loss group performed significantly worse than the normal hearing group regardless of contextual cues. These results suggest that neither of the older groups was able to benefit from the use of context in these rapid speech materials. Implications of these speech recognition test results will be discussed with regard to the neurocognitive findings.
Auditory evoked potentials to changes in interaural cross correlation
Authors: Riedel Helmut , Lüddemann Helge , Kollmeier Birger
Published: October 2013

The objective of this study is to analyze the representation of specific binaural stimulus features in the human brain and to compare the results to psychoacoustic data. Late auditory evoked potentials to changes in the interaural cross correlation (IACC) of continuous bandpass noise (100–2000 Hz) were recorded, 1000 sweeps per stimulus condition were averaged. In experiment 1 a brief ‘‘binaural gap’’ with a gap IACC was interposed in the noise with a reference IACC. N1 and P2 amplitudes increased with increasing gap duration. For uncorrelated reference IACC (0/1/0 and 0/−1/0 conditions) objective thresholds were comparable to psychoacoustic data. For uncorrelated gap IACC (1/0/1 and −1/0/−1 conditions) objective thresholds were about four times larger than in psychoacoustic measurements. In experiment 2 reference and test interval had the same length of 800 ms and the magnitude of change in IACC was varied. Objective IACC-JNDs are larger for an uncorrelated reference than for IACCs of ±1. For the uncorrelated reference, test IACCs towards +1 elicited larger AEP components than test IACCs towards −1. In contrast to binaural difference potentials used at the brain stem level, employing changes in IACC constitutes a more direct approach to objectively investigate the binaural system in humans.
Automatic species identification of odontocete calls in the Southern California Bight
Authors: Roch Marie , Soldevilla Melissa , Hildebrand John
Published: October 2013

In this work, a method for the automatic classification of odontocete species from their vocalizations is presented. We consider the vocalizations of three dolphin species which were recorded in a pelagic environment of the southern California Bight over a period of approximately three years. 57B naval sonobuoys sampling at 48 kHz were used to record the calls of common (Delphinus delphis), Risso’s (Grampus griseus) and Pacific white-sided (Lagenorhynchus obliquidens) dolphins. In this study, approximately 3 h of calls were selected, with a disproportionate number of common dolphin calls appearing. An emphasis has been made on classifying calls across recording sessions, thus illustrating the system’s ability to perform classification in different acoustic environments with a high likelihood of different individuals performing the vocalizations. Cepstral feature vectors are extracted from manually endpointed call data and classified using a Gaussian mixture model system. The performance of the automatic classification compares favorably with human performance.
Production and perception of clear speech in Croatian and English
Authors: Smiljanic Rajka , Bradlow Ann
Published: October 2013

This paper presents a cross-language comparison of clear speech, a distinct mode of speech production intended to enhance intelligibility. Specifically, it explores whether language specific phonological properties guide the articulatory modifications of clear speech in Croatian and English, and examines whether clear speech enhances intelligibility in both languages. Five Croatian and five English speakers read 20 nonsense sentences in Croatian and English, respectively, in conversational and clear speaking styles. In a sentence-in-noise perception test, listeners recognized words more accurately in clear than in conversational speech in their native language, establishing that the clear speech intelligibility effect is not English-specific. Acoustic analyses showed that both phonemic (e.g., the vowel length contrast in Croatian) and allophonic (e.g., the tense versus lax vowel duration difference in English) contrasts are enhanced in clear speech. Furthermore, speakers enhance contrasts even when categories seem to be sufficiently distinct and there is little chance of confusability. For example, the vowel space is expanded equally in English (with 11 vowels) and in Croatian (with just five vowel qualities). The results suggest that clear speech production is driven by the phonological properties of the language, but at the same time all segments are hyperarticulated regardless of inventory based considerations.
Automatic song-type classification and individual identification of the ortolan bunting (Emberiza hortulana L) bird vocalizations
Authors: Adi Kuntoro , Osiejuk Tomasz S. , Johnson Michael T.
Published: October 2013

This paper presents a method for automatic song-type classification and individual identification of the ortolan bunting (emberiza hortulana L). This method is based on hidden markov models (HMMs) commonly used in the signal processing and automatic speech recognition research communities. The features used for classification and identification include both fundamental frequency and spectral characteristics. Fundamental frequency features consist of center frequency f0, relative f0 to moving-average baseline, peak strength, and peak bandwidth. Spectral features are derived from frequency-weighted cepstral coefficients. Using these features one HMM is trained for each type of vocalization both for each individual bird and across the entire population. Preliminary results indicate accuracies of above 90% for both song-type classification and individual identification tasks.
Vibro-acoustic launch protection experiment (VALPE)
Authors: Henderson Benjamin , Gerhart Charlotte , Lane Steven , Jensen Elizabeth , Griffin Steve , Lazzaro Anthony
Published: October 2013

Launch acoustic and vibration loads have the potential to damage sensitive payloads within a payload fairing, often requiring more structural mass to withstand these loads than would otherwise be necessary to survive launch. Experiments demonstrating several vibro-acoustic mitigation technologies developed by AFRL/VS and its contractors flew on the Vibro-Acoustic Launch Protection Experiment 2 (VALPE-2) aboard a Terrier-Improved Orion sounding rocket from Wallops Island Flight Facility in August 2003. Flight data collected in November 2002 from a nearly identical launch (VALPE-1) was used to characterize the fairing environment for comparison. Preparations for the flight experiments are discussed along with the performance of the various experiments in flight. The several experiments include an Adaptive Vibro-Acoustic Device (AVAD) to mitigate acoustic loads, an active/passive hybrid vibration isolation system using voice-coil actuation and a ShockRing passive component, a voice-coil regenerative electronics vibration isolation system to absorb a portion of the vibration energy during launch and use it to power an active isolation system during a staging event, and a ChamberCore composite fairing with implications for passive acoustic performance.
Return of the Steroid
Authors: Wigginton Nicholas S.
Published: October 2013

Phototransformation of growth steroid metabolites is readily reversible in aquatic environments.
Distinctive Origin and Spread Route of Pyrimethamine-Resistant Plasmodium falciparum in Southern China
Authors: Zhang Yilong , Yan He , Wei Guiying , Han Shitong , Huang Yufu , Zhang Qingfeng , Pan Weiqing
Published: October 2013

Southeast Asia (the Thailand-Cambodia border) has been considered the primal epicenter for most antimalarial drug resistance; however, numerous molecular epidemiological studies have successively reported multiple independent origins of sulfadoxine-pyrimethamine (SP) resistance-associated
Plasmodium falciparum
dhfr
(
pfdhfr
) and
pfdhps
alleles in other areas. To better understand the origin and evolutionary pathway of the SP resistance in Southeast Asia, a total of 374
P. falciparum
field isolates from the Yunnan-Burma border and Hainan Island in southern China have been collected for comprehensive investigations on the mutation patterns of the
pfdhfr
/
pfdhps
genes as well as their microsatellite haplotypes. By comparative analysis of single-nucleotide polymorphism (SNP) genotyping and flanking microsatellite haplotypes, we reveal a unique origin of pyrimethamine-resistant mutations in
Pfdhfr
gene in Hainan Island and an oriented spread route of the pyrimethamine resistance from the Thailand-Cambodia border into the Hainan area, which reflects the geographical traits and SP administration histories in the two geographically independent areas. Moreover, genetic linkages between the high-level SP resistance-conferring
pfdhfr
/
pfdhps
alleles have been established in the isolates from the Yunnan-Burma border, raising the concern of a genetic basis in adopting combination chemotherapies against falciparum malaria.
Prevalence of Polymorphisms in Antifolate Drug Resistance Molecular Marker Genes
pvdhfr
and
pvdhps
in Clinical Isolates of Plasmodium vivax from Kolkata, India
Authors: Ganguly Swagata , Saha Pabitra , Chatterjee Moytrey , Maji Ardhendu K.
Published: October 2013

Sulfadoxine-pyrimethamine has never been recommended for the treatment of
Plasmodium vivax
malaria as the parasite is intrinsically resistant to pyrimethamine. The combination was introduced as a promising agent to treat
Plasmodium falciparum
malaria in many countries but was withdrawn after a few years due to development and spread of resistant strains. Presently, sulfadoxine-pyrimethamine is used as a partner drug of artemisinin-based combination therapy to treat uncomplicated falciparum malaria, and a combination of artesunate-sulfadoxine-pyrimethamine is currently in use in India. In countries like India, where both
P. vivax
and
P. falciparum
are equally prevalent, some proportion of
P. vivax
bacteria is exposed to sulfadoxine-pyrimethamine due to misdiagnosis and mixed infections. As reports on the
in vivo
therapeutic efficacy of sulfadoxine-pyrimethamine in
P. vivax
are rare, the study of mutations in the marker genes
P. vivax
dhfr
(
pvdhfr
) and
pvdhps
is important for predicting drug selection pressure and sulfadoxine-pyrimethamine resistance monitoring. We studied the prevalence of point mutations and haplotypes of both the genes in 80
P. vivax
isolates collected from urban Kolkata, India, by the DNA sequencing method. Point mutation rates in both the genes were low. The double mutant
pvdhfr
A
15
N
50
R
58
N
117
I
173
(mutations are in boldface) and the single mutant
pvdhps
genotype S
382
G
383
K
512
A
553
V
585
were more prevalent, while 35% of the isolates harbored the wild-type genotype. The triple mutant AN
RN
I-S
G
KAV was found in 29.9% isolates. No quintuple mutant genotype was recorded. The
P. vivax
parasites in urban Kolkata may still be susceptible to sulfadoxine-pyrimethamine. Hence, a combination of antimalarial drugs like artesunate-sulfadoxine-pyrimethamine introduced for
P. falciparum
infection might be effective in
P. vivax
infection also. Study of the therapeutic efficacy of this combination in
P. vivax
is thus strongly suggested. (The study protocol was registered in the Clinical Trial Registry-India [CTRI] of the Indian Council of Medical Research under registration number CTRI/2011/09/002031.)
Multiple Mutations Lead to MexXY-OprM-Dependent Aminoglycoside Resistance in Clinical Strains of Pseudomonas aeruginosa
Authors: Guénard Sophie , Muller Cédric , Monlezun Laura , Benas Philippe , Broutin Isabelle , Jeannot Katy , Plésiat Patrick
Published: October 2013

Constitutive overproduction of the pump MexXY-OprM is recognized as a major cause of resistance to aminoglycosides, fluoroquinolones, and zwitterionic cephalosporins in
Pseudomonas aeruginosa
. In this study, 57 clonally unrelated strains recovered from non-cystic fibrosis patients were analyzed to characterize the mutations resulting in upregulation of the
mexXY
operon. Forty-four (77.2%) of the strains, classified as
agrZ
mutants were found to harbor mutations inactivating the local repressor gene (
mexZ
) of the
mexXY
operon (
n
= 33; 57.9%) or introducing amino acid substitutions in its product, MexZ (
n
= 11; 19.3%). These sequence variations, which mapped in the dimerization domain, the DNA binding domain, or the rest of the MexZ structure, mostly affected amino acid positions conserved in TetR-like regulators. The 13 remaining MexXY-OprM strains (22.8%) contained intact
mexZ
genes encoding wild-type MexZ proteins. Eight (14.0%) of these isolates, classified as
agrW1
mutants, overexpressed the gene PA5471, which codes for the MexZ antirepressor AmrZ, with 5 strains exhibiting growth defects at 37°C and 44°C, consistent with mutations impairing ribosome activity. Interestingly, one
agrW1
mutant appeared to harbor a 7-bp deletion in the coding sequence of the leader peptide, PA5471.1, involved in ribosome-dependent, translational attenuation of PA5471 expression. Finally, DNA sequencing and complementation experiments revealed that 5 (8.8%) strains, classified as
agrW2
mutants, harbored single amino acid variations in the sensor histidine kinase of ParRS, a two-component system known to positively control
mexXY
expression. Collectively, these results demonstrate that clinical strains of
P. aeruginosa
exploit different regulatory circuitries to mutationally overproduce the MexXY-OprM pump and become multidrug resistant, which accounts for the high prevalence of MexXY-OprM mutants in the clinical setting.
Curcumin Targets Cell Wall Integrity via Calcineurin-Mediated Signaling in Candida albicans
Authors: Kumar Awanish , Dhamgaye Sanjiveeni , Maurya Indresh Kumar , Singh Ashutosh , Sharma Monika , Prasad Rajendra
Published: October 2013

Curcumin (CUR) shows antifungal activity against a range of pathogenic fungi, including
Candida albicans
. The reported mechanisms of action of CUR include reactive oxygen species (ROS) generation, defects in the ergosterol biosynthesis pathway, decrease in hyphal development, and modulation of multidrug efflux pumps. Reportedly, each of these pathways is independently linked to the cell wall machinery in
C. albicans
, but surprisingly, CUR has not been previously implicated in cell wall damage. In the present study, we performed transcriptional profiling to identify the yet-unidentified targets of CUR in
C. albicans
. We found that, among 348 CUR-affected genes, 51 were upregulated and 297 were downregulated. Interestingly, most of the cell wall integrity pathway genes were downregulated. The possibility of the cell wall playing a critical role in the mechanism of CUR required further validation; therefore, we performed specific experiments to establish if there was any link between the two. The fractional inhibitory concentration index values of 0.24 to 0.37 show that CUR interacts synergistically with cell wall-perturbing (CWP) agents (caspofungin, calcofluor white, Congo red, and SDS). Furthermore, we could observe cell wall damage and membrane permeabilization by CUR alone, as well as synergistically with CWP agents. We also found hypersusceptibility in calcineurin and mitogen-activated protein (MAP) kinase pathway mutants against CUR, which confirmed that CUR also targets cell wall biosynthesis in
C. albicans
. Together, these data provide strong evidence that CUR disrupts cell wall integrity in
C. albicans
. This new information on the mechanistic action of CUR could be employed in improving treatment strategies and in combinatorial drug therapy.
Deletion of the β-Acetoacetyl Synthase FabY in Pseudomonas aeruginosa Induces Hypoacylation of Lipopolysaccharide and Increases Antimicrobial Susceptibility
Authors: Six David A. , Yuan Yanqiu , Leeds Jennifer A. , Meredith Timothy C.
Published: October 2013

The β-acetoacetyl-acyl carrier protein synthase FabY is a key enzyme in the initiation of fatty acid biosynthesis in
Pseudomonas aeruginosa
. Deletion of
fabY
results in an increased susceptibility of
P. aeruginosa
in vitro
to a number of antibiotics, including vancomycin and cephalosporins. Because antibiotic susceptibility can be influenced by changes in membrane lipid composition, we determined the total fatty acid profile of the Δ
fabY
mutant, which suggested alterations in the lipid A region of the lipopolysaccharide. The majority of lipid A species in the Δ
fabY
mutant lacked a single secondary lauroyl group, resulting in hypoacylated lipid A. Adding exogenous fatty acids to the growth media restored the wild-type antibiotic susceptibility profile and the wild-type lipid A fatty acid profile. We suggest that incorporation of hypoacylated lipid A species into the outer membrane contributes to the shift in the antibiotic susceptibility profile of the Δ
fabY
mutant.
Effect of Mature Blood-Stage Plasmodium Parasite Sequestration on Pathogen Biomass in Mathematical and
In Vivo
Models of Malaria
Authors: Khoury David S. , Cromer Deborah , Best Shannon E. , James Kylie R. , Kim Peter S. , Engwerda Christian R. , Haque Ashraful , Davenport Miles P.
Published: October 2013

Parasite biomass and microvasculature obstruction are strongly associated with disease severity and death in
Plasmodium falciparum
-infected humans. This is related to sequestration of mature, blood-stage parasites (schizonts) in peripheral tissue. The prevailing view is that schizont sequestration leads to an increase in pathogen biomass, yet direct experimental data to support this are lacking. Here, we first studied parasite population dynamics in inbred wild-type (WT) mice infected with the rodent species of malaria,
Plasmodium berghei
ANKA. As is commonly reported, these mice became moribund due to large numbers of parasites in multiple tissues. We then studied infection dynamics in a genetically targeted line of mice, which displayed minimal tissue accumulation of parasites. We constructed a mathematical model of parasite biomass dynamics, incorporating schizont-specific host clearance, both with and without schizont sequestration. Combined use of mathematical and
in vivo
modeling indicated, first, that the slowing of parasite growth in the genetically targeted mice can be attributed to specific clearance of schizonts from the circulation and, second, that persistent parasite growth in WT mice can be explained solely as a result of schizont sequestration. Our work provides evidence that schizont sequestration could be a major biological process driving rapid, early increases in parasite biomass during blood-stage
Plasmodium
infection.
Geology and Mineral Deposits of the Superior Province of the Canadian Shield
Authors: Card K.D. , Poulsen K. Howard
Published: October 2013

It has been the custom of the Geological Survey of Canada (GSC) to periodically publish a summary account of the geology and economic mineral deposits of Canada. Such ‘Geology and Economic Minerals of Canada’ volumes were published in 1909, 1926, 1946, 1957, and 1970. During the 1980s, in lieu of a sixth edition, the GSC embarked on the production of a series of more comprehensive ‘Geology of Canada’ volumes as part of the Geological Society of America (GSA) Decade of North American Geology (DNAG) series. Much of the material for this review of the geology and economic minerals of Superior Province was prepared as part of the DNAG initiative but, due to revised operational requirements, the integration of the geological and metallogenic aspects arose much later. In this integrated review, we place particular emphasis on advances that have taken place in the 25 years since the last summaries of this kind (Stockwell et al., 1970; Lang et al., 1970; Goodwin, 1972).

The Archean Superior Craton forms the core of the North American continent (Fig. 2.1) and is surrounded and truncated on all sides by Proterozoic orogens, the collisional zones along which the elements of the Precambrian Canadian Shield were amalgamated (Hoffman, 1988, 1989). The Superior Province (Fig. 2.2) is the 2 × 106 km2 region of this craton which is free of significant post-Archean cover rocks and deformation. The rocks of Superior Province are of mainly Meso- and Neoarchean age and have been significantly affected by post-Archean deformation only along
Synopsis of Precambrian Fossil Occurrences in North America
Authors: Hofmann H.J.
Published: October 2013

The purpose of this paper is to provide a general, current overview of the Precambrian fossil occurrences in North America. This work, a sequel to earlier compilations for Canada (See Hofmann, 1971, 1972, 1981a), has been expanded to encompass the remainder of North America, for which similar compilations are not available (except for the western United States and northwestern Mexico: Horodyski, 1993a, b). On the other hand, several comprehensive monographs on the global Precambrian paleontological record (Schopf, 1983; Schopf and Klein, 1992; Bengtson, 1994) provide impressive detail with global coverage of all aspects of Precambrian paleobiology and evolution. Another topical volume that includes chapters on Precambrian stromatolite reef complexes is Geldsetzer et al. (1989). All the above references have extensive documentation and bibliographies. The present inventory is meant to complement this previous work by providing a synoptic view of North American occurrences in map form (Fig. 4.1, in pocket; Fig. 4.2–4.13), and some observations on the content of the database. This perspective allows a better continent-wide overview of geographic data than tabulated data dispersed in various publications; moreover, lateral relationships of areas where previous work has been concentrated, and those where data are not available, are more readily visualized. This continental overview should be helpful for those contemplating future paleontological work in the Precambrian sequences of North America.

Fossils and possible fossils have been reported from at least 383 formations in North America attributed to the Precambrian. These 383 occurrences, known up to mid-1996 from Canada, Greenland, U.S.A., and Mexico,
High-intensity interval training in patients with lifestyle-induced cardiometabolic disease: a systematic review and meta-analysis
Authors: Weston Kassia S , Wisløff Ulrik , Coombes Jeff S
Published: October 2013

Background/Aim

Cardiorespiratory fitness (CRF) is a strong determinant of morbidity and mortality. In athletes and the general population, it is established that high-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. This is a systematic review and meta-analysis to quantify the efficacy and safety of HIIT compared to MICT in individuals with chronic cardiometabolic lifestyle diseases.

Methods

The included studies were required to have a population sample of chronic disease, where poor lifestyle is considered as a main contributor to the disease. The procedural quality of the studies was assessed by use of a modified Physiotherapy Evidence Base Database (PEDro) scale. A meta-analysis compared the mean difference (MD) of preintervention versus postintervention CRF (VO2peak) between HIIT and MICT.

Results

10 studies with 273 patients were included in the meta-analysis. Participants had coronary artery disease, heart failure, hypertension, metabolic syndrome and obesity. There was a significantly higher increase in the VO2peak after HIIT compared to MICT (MD 3.03 mL/kg/min, 95% CI 2.00 to 4.07), equivalent to 9.1%.

Conclusions

HIIT significantly increases CRF by almost double that of MICT in patients with lifestyle-induced chronic diseases.
Sedentary behaviour and physical inactivity assessment in primary care: the Rapid Assessment Disuse Index (RADI) study
Authors: Shuval Kerem , Kohl Harold W , Bernstein Ira , Cheng Dunlei , Pettee Gabriel Kelley , Barlow Carolyn E , Yinghui Liu , DiPietro Loretta
Published: October 2013

Background

The emerging evidence of the effects of sedentary time on health outcomes suggests a need to better measure this exposure. Healthcare settings, however, are not equipped with a tool that can quickly assess the sedentary habits of their patient population. The purpose of this study was to validate a tool for rapidly quantifying and tracking the sedentary time and low levels of daily lifestyle physical activity among primary care patients.

Methods

The study examined the test–retest reliability and validity of the rapid assessment disuse index (RADI) among adult patients from a large primary care clinic. Patients completed RADI (comprised of 3 items: sitting, moving and stair climbing) twice, followed by accelerometer monitoring. Test–retest reliability was computed, and the correlation between survey responses and accelerometry was determined. A receiver operating characteristic curve was constructed and the area under the curve (AUC) was calculated.

Results

RADI was temporally stable (intraclass correlation coefficients 0.79), and a higher score was significantly correlated with greater sedentary time (ρ=0.40; p<0.01), fewer sedentary to active transitions (ρ=−0.42; p<0.01), and less light-intensity physical activity (ρ=−0.40; p<0.01). The ability of RADI to detect patients with high levels of sedentary time was fair (AUC=0.72).

Conclusions

This brief assessment tool, designed to quickly identify patients with high levels of sitting and low daily physical activity, exhibits good reliability and moderate validity. RADI can assist in providing recommendations at the point of care pertaining to modifying sedentary behaviour.
Clinical features, outcome and prognostic factors in dogs diagnosed with non‐cortisol‐secreting adrenal tumours without adrenalectomy: 20 cases (1994–2009)
Authors: Arenas C. , Pérez‐Alenza D. , Melián C.
Published: October 2013

The aims of this study were to describe the clinical features, the outcome and the prognostic factors of dogs with non‐cortisol‐secreting adrenal masses without adrenalectomy, and also to provide clinical data that can be useful for making decisions when managing dogs with these types of neoplasms. Medical records from 1994 to 2009 were reviewed and 20 dogs were included in the study. The results showed that mean age at diagnosis for dogs with non‐cortisol‐secreting adrenal masses was 12 years with no sex predisposition. Most dogs were asymptomatic. The most frequent clinical signs, when present, were lethargy, weakness and hypertension. Radiological evidence of metastases at diagnosis was not frequent. The maximal dorso‐ventral thickness of the adrenal mass ranged from 10.0 to 45.0 mm. Right adrenal gland masses were more frequent than left‐sided. Hypertension was found to be related to tumour growth during follow‐up. The median survival time of dogs with non‐cortisol‐secreting tumours was 17.8 months. Body weight at diagnosis, tumour size and the presence of metastases at diagnosis were inversely related to survival. In conclusion, survival of dogs with non‐cortisol‐secreting adrenal tumours without adrenalectomy is relatively high and comparable with that of dogs treated with adrenalectomy. Dogs with metastasis and large adrenal tumours have a poorer prognosis. Hypertension is related to tumour growth, and might be used as an additional tool to assess the potential growing capacity of the tumour.
Effects of a freeze-dried juice blend powder on exercise-induced inflammation, oxidative stress, and immune function in cyclists
Authors: Knab Amy M. , Nieman David C. , Gillitt Nicholas D. , Shanely R. Andrew , Cialdella-Kam Lynn , Henson Dru , Sha Wei , Meaney Mary Pat
Published: October 2013

A freeze-dried fruit and vegetable juice powder (JUICE) was investigated as a countermeasure nutritional strategy to exercise-induced inflammation, oxidative stress, and immune perturbations in trained cyclists. Thirty-four cyclists (25 male, 9 female) were randomized to control (nonJUICE) or JUICE for 17 days. JUICE provided 230 mg·day−1 of flavonoids, doubling the typical adult daily intake. During a 3-d period of intensified exercise (days 15–17), subjects cycled at 70%–75% V̇O2max for 2.25 h per day, followed by a 15-min time trial. Blood samples were collected presupplementation, post supplementation (pre-exercise), and immediately and 14-h post exercise on the third day of exercise. Samples were analyzed for inflammation (interleukin (IL)-6, IL-8; tumor necrosis factor alpha (TNFα); monocyte chemoattractant protein-1 (MCP-1)), oxidative stress (oxygen radical absorbance capacity (ORAC), ferric reducing ability of plasma (FRAP), reduced and oxidized glutathione, protein carbonyls), and innate immune function (granulocyte (G-PHAG) and monocyte (M-PHAG) phagocytosis and oxidative burst activity). A 2 (group) × 4 (time points) repeated measures ANOVA revealed significant time effects due to 3 days of exercise for IL-6 (396% increase), IL-8 (78% increase), TNFα (12% increase), MCP-1 (30% increase), G-PHAG (38% increase), M-PHAG (36% increase), FRAP (12.6% increase), ORAC (11% decrease at 14 h post exercise), and protein carbonyls (82% increase at 14 h post exercise) (p < 0.01). No significant interaction effects were found for any of the physiological measures. Although providing 695 gallic acid equivalents of polyphenols per day, JUICE treatment for 17 days did not change exercise-induced alterations in inflammation and oxidative stress or immune function in trained cyclists after a 3-day period of overreaching.