bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wave-number analysis of active structural acoustic control of sound transmission through a panel
Authors: Mathur Gopal P. , Tran Boi N. 
Published: October 2005

Active control of sound transmission through elastic structures, such as panels using structural inputs, has received considerable attention in recent years. The active control technique of improving structural transmission loss (TL) by applying control forces directly to the transmitting structure using single or multiple piezoelectric actuators mounted on the structure rather than using acoustic canceling sources is known as active structural acoustic control (ASAC) method. This paper presents results of experimental investigations of ASAC method in improving the TL of a panel. Wave-number analysis was employed to understand the mechanism of improving the TL of a panel using multiple piezoceramic actuators. Experiments were conducted to measure near-field sound radiation from a baffled panel (dimensions: 1.75 m×1.14 m×1.27 mm) subjected to acoustic excitation for both with and without active control conditions. The active control of the panel TL was achieved by four piezoceramic actuators mounted on the panel. An array of four microphones placed about 1 m away from the panel were used as error transducers for a multiple-input multiple-output active control system. The transmitted acoustic field was measured by a two-dimensional array of microphones (array size: 22×14). The wave-number frequency spectra of the sound field were obtained by implementing Fourier transforms on the spatial domain data. Sound intensity measurements were also made to determine improvements in panel transmission loss.
Comparison of measured wave-number spectrum for the active control condition with that of baseline (without control) showed that sound radiation from the acoustically fast lower-order modes at low wave numbers is significantly reduced. Results from the near-field acoustical holographic measurements will also be discussed. The relative reduction in sound power levels due to ASAC estimated from the near-field holographic measurements compared very well with those obtained from sound intensity measurements.
The incorporation of level and level-invariant cues for the detection of a tone added to noise
Authors: Richards Virginia M. , Nekrich Robert D. 
Published: October 2005

The potential contribution of level-dependent and level-invariant cues for the detection of a tone added to narrow bands of noise was assessed in two experiments. In the first experiment, three masker bandwidths, 40, 120, and 360 Hz, and three center frequencies, 600, 1800, and 5400 Hz were tested. For the tone-in-noise detection task, the signal to be detected was a tone with a frequency equal to the center frequency of the noise masker. The level of the added tone was adjusted so as to generate d′ scores of approximately 2 in a two-alternative, forced-choice procedure. Then, the distributions of across-interval changes in level were measured. The distribution of differences in level was applied to either the noise-alone or the tone-plus-noise stimuli, allowing the measurement of sensitivity to changes in level for a two-interval, forced-choice intensity discrimination task. For one of the four observers, there was a good correspondence between the d′ values obtained in the tone-in-noise task and the d′ values obtained in the intensity discrimination task. For the other three observers, the discriminability of changes in intensity could not account for the detection of a tone added to noise. In order to estimate sensitivity to level-invariant cues, the noise-alone and tone-plus-noise waveforms were scaled so as to present no reliable differences in level, and observers again detected which stimulus contained the added tone.
Normalization led to d′ scores smaller than those obtained in the initial tone-in-noise discrimination task, but performance levels did not fall to chance. For three of the four observers, the detection of a tone added to noise appeared to depend on both level and level-invariant cues. In a second experiment, psychometric functions were obtained for the detection of a tone added to noise, for the detection of changes in level associated with the noise-alone and the tone-plus-noise stimuli, and for the detection of a tone added to noise using noise-alone and tone-plus-noise waveforms with no reliable differences in level. The maskers were centered at 1800 Hz, and bandwidths of 40 and 100 Hz were tested. Individual differences in detection strategy were obtained. Two observers appeared to rely on changes in level, one observer appeared to rely on level-invariant cues, and the remaining four observers appeared to adopt a decision strategy that integrated level and level-invariant cues. The results suggest that (a) both level-dependent and level-invariant cues are available to the observer for the detection of a tone added to noise, and (b) different observers employ the cues in different ways.
Sampling requirements and aliasing for higher-order correlations
Authors: Pflug Lisa A. , Ioup George E. , Ioup Juliette W. 
Published: October 2005

While sampling at a Nyquist frequency equal to the highest frequency present in the data (critical sampling) is sufficient to prevent aliasing in both the data and the autocorrelation of a bandlimited energy signal, the sampling requirements for the avoidance of aliasing in higher-order correlations and spectra are not the same. Also, there is a difference in aliasing effects depending on whether one samples the original continuous-time signal and calculates the autocorrelation or one samples the continuous-time autocorrelation. This distinction between sampling procedures must be made for correlations of higher order, as well, for which not only the type of aliasing but also the sampling requirements to prevent aliasing differ. In particular, if one samples the continuous-time autobicorrelation or autotricorrelation, critical sampling is sufficient to prevent aliasing. In practice, however, it is not usually the continuous-time autobicorrelation or autotricorrelation that is sampled. Generally, it is the original continuous-time signal that is sampled and used to calculate the discrete-time autobicorrelation or autotricorrelation. In this case, to prevent aliasing, the sampling interval for the autobicorrelation must be no greater than two-thirds the interval associated with critical sampling, and no greater than one-half for the autotricorrelation.
Numerical calculations of autocorrelation, autobicorrelation, and autotricorrelation zero-lag values corresponding to spectral area and volume as well as bispectral contour plots for two model bandlimited energy signals are presented as demonstrations of these conclusions. Sampling requirements for higher-order correlations of rectified signals are also discussed. If the signal is to be rectified for use in a correlation detector or time delay estimator, then the sampling rate must increase to accommodate the higher frequencies that usually result from the process of rectification. Spectral masking filters, which remove aliasing in higher-order correlations, are defined and a bispectral filter is applied to some representative energy signals. Lag domain convolution filters for the removal of aliasing in the bicorrelation and tricorrelation are also given. These filters assume critical sampling or finer for the original signal to remove aliasing effects totally.
Stimulus features affecting psychophysical detection thresholds for electrical stimulation of the cochlea. II: Frequency and interpulse interval
Authors: Pfingst Bryan E. , Morris Deborah J. 
Published: October 2005

Psychophysical detection thresholds for electrical stimulation of the cochlea were measured in nonhuman primates (macaques) as part of a series of experiments exploring the stimulus features affecting detection. The monkeys were trained psychophysically using operant conditioning. One ear was treated with neomycin to destroy hair cells, and implanted with electrodes in the scala tympani and/or the cochlear wall. In experiment 1, detection thresholds were measured for trains of fixed-duration pulses and for sinusoids. For long-duration pulses (1 to 2 ms/phase), thresholds decreased as a function of frequency (pulse rate), reaching a minimum at a frequency between 125 and 210 pps, then increased as frequency was further increased. For shorter duration pulses, thresholds usually decreased monotonically as a function of frequency but sometimes showed a slight increase as a function of frequency near the highest frequencies tested. Typically slopes of the threshold versus frequency functions for fixed-duration pulses were equal to or less than slopes of threshold versus frequency functions for sinusoidal signals, where frequency and phase duration covaried. Additional observations on two of the cases were made in experiments 2 and 3. In experiment 2, thresholds for pairs of pulses were measured as a function of interpulse interval. Thresholds decreased as a function of interpulse interval up to intervals of 2 to 4 ms and then increased slightly. In experiment 3, thresholds were measured as a function of stimulus duration at two frequencies.
Thresholds decreased as a function of stimulus duration at a greater rate for the lower frequency pulse train, so that the difference between the detection thresholds for the two signals increased as a function of stimulus duration. These experiments suggest that stimulus frequency (i.e., repetition rate with phase duration fixed) is a significant contributor to the detection of electrical signals. This contribution may be due to a combination of effects of (a) increasing the number of neural responses to the stimulus as frequency is increased, and (b) temporal interactions of those responses, as interpulse intervals become small, due to refractory periods or other periods of altered excitability that follow a pulse.
Biological Transmission of Arboviruses: Reexamination of and New Insights into Components, Mechanisms, and Unique Traits as Well as Their Evolutionary Trends
Authors: Kuno Goro , Chang Gwong-Jen J. 
Published: October 2005

SUMMARYAmong animal viruses, arboviruses are unique in that they depend on arthropod vectors for transmission. Field research and laboratory investigations related to the three components of this unique mode of transmission, virus, vector, and vertebrate host, have produced an enormous amount of valuable information that may be found in numerous publications. However, despite many reviews on specific viruses, diseases, or interests, a systematic approach to organizing the available information on all facets of biological transmission and then to interpret it in the context of the evolutionary process has not been attempted before. Such an attempt in this review clearly demonstrates tremendous progress made worldwide to characterize the viruses, to comprehend disease transmission and pathogenesis, and to understand the biology of vectors and their role in transmission. The rapid progress in molecular biologic techniques also helped resolve many virologic puzzles and yielded highly valuable data hitherto unavailable, such as characterization of virus receptors, the genetic basis of vertebrate resistance to viral infection, and phylogenetic evidence of the history of host range shifts in arboviruses. However, glaring gaps in knowledge of many critical subjects, such as the mechanism of viral persistence and the existence of vertebrate reservoirs, are still evident. Furthermore, with the accumulated data, new questions were raised, such as evolutionary directions of virus virulence and of host range. Although many fundamental questions on the evolution of this unique mode of transmission remained unresolved in the absence of a fossil record, available observations for arboviruses and the information derived from studies in other fields of the biological sciences suggested convergent evolution as a plausible process. Overall, discussion of the diverse range of theories proposed and observations made by many investigators was found to be highly valuable for sorting out the possible mechanism(s) of the emergence of arboviral diseases.
Tick-Borne Rickettsioses around the World: Emerging Diseases Challenging Old Concepts
Authors: Parola Philippe , Paddock Christopher D. , Raoult Didier 
Published: October 2005

SUMMARYDuring most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. An element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. In this context, it was considered that relatively few tick-borne rickettsiae caused human disease. This concept was modified extensively from 1984 through 2005 by the identification of at least 11 additional rickettsial species or subspecies that cause tick-borne rickettsioses around the world. Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established. We present here the tick-borne rickettsioses described through 2005 and focus on the epidemiological circumstances that have played a role in the emergence of the newly recognized diseases.
ADVICE FOR SEMIFEASIBLE SETS AND THE COMPLEXITY-THEORETIC COST(LESSNESS) OF ALGEBRAIC PROPERTIES
Authors: FALISZEWSKI PIOTR , HEMASPAANDRA LANE A. 
Published: October 2005

Informally put, the semifeasible sets are the class of sets having a polynomial-time algorithm that, given as input any two strings of which at least one belongs to the set, will choose one that does belong to the set. We provide a tutorial overview of the advice complexity of the semifeasible sets. No previous familiarity with either the semifeasible sets or advice complexity will be assumed, and when we include proofs we will try to make the material as accessible as possible via providing intuitive, informal presentations. Karp and Lipton introduced advice complexity about a quarter of a century ago.18 Advice complexity asks, for a given power of interpreter, how many bits of "help" suffice to accept a given set. Thus, this is a notion that contains aspects both of descriptional/informational complexity and of computational complexity. We will see that for some powers of interpreter the (worst-case) complexity of the semifeasible sets is known right down to the bit (and beyond), but that for the most central power of interpreter—deterministic polynomial time—the complexity is currently known only to be at least linear and at most quadratic. While overviewing the advice complexity of the semifeasible sets, we will stress also the issue of whether the functions at the core of semifeasibility—so-called selector functions—can without cost be chosen to possess such algebraic properties as commutativity and associativity. We will see that this is relevant, in ways both potential and actual, to the study of the advice complexity of the semifeasible sets.
Better prediction of protein contact number using a support vector regression analysis of amino acid sequence
Authors: Yuan Zheng 
Published: October 2005

Abstract
Background
Protein tertiary structure can be partly characterized via each amino acid's contact number measuring how residues are spatially arranged. The contact number of a residue in a folded protein is a measure of its exposure to the local environment, and is defined as the number of C
β
atoms in other residues within a sphere around the C
β
atom of the residue of interest. Contact number is partly conserved between protein folds and thus is useful for protein fold and structure prediction. In turn, each residue's contact number can be partially predicted from primary amino acid sequence, assisting tertiary fold analysis from sequence data. In this study, we provide a more accurate contact number prediction method from protein primary sequence.

Results
We predict contact number from protein sequence using a novel support vector regression algorithm. Using protein local sequences with multiple sequence alignments (PSI-BLAST profiles), we demonstrate a correlation coefficient between predicted and observed contact numbers of 0.70, which outperforms previously achieved accuracies. Including additional information about sequence weight and amino acid composition further improves prediction accuracies significantly with the correlation coefficient reaching 0.73. If residues are classified as being either "contacted" or "non-contacted", the prediction accuracies are all greater than 77%, regardless of the choice of classification thresholds.

Conclusion
The successful application of support vector regression to the prediction of protein contact number reported here, together with previous applications of this approach to the prediction of protein accessible surface area and B-factor profile, suggests that a support vector regression approach may be very useful for determining the structure-function relation between primary protein sequence and higher order consecutive protein structural and functional properties.
Efficient expression of transgenes in adult zebrafish by electroporation
Authors: Rambabu K Murali , Rao S Hari Narayana , Rao N Madhusudhana 
Published: October 2005

Abstract

Background
Expression of transgenes in muscle by injection of naked DNA is widely practiced. Application of electrical pulses at the site of injection was demonstrated to improve transgene expression in muscle tissue. Zebrafish is a precious model to investigate developmental biology in vertebrates. In this study we investigated the effect of electroporation on expression of transgenes in 3–6 month old adult zebrafish.

Results
Electroporation parameters such as number of pulses, voltage and amount of plasmid DNA were optimized and it was found that 6 pulses of 40 V·cm-1 at 15 μg of plasmid DNA per fish increased the luciferase expression 10-fold compared to controls. Similar enhancement in transgene expression was also observed in Indian carp (Labeo rohita). To establish the utility of adult zebrafish as a system for transient transfections, the strength of the promoters was compared in A2 cells and adult zebrafish after electroporation. The relative strengths of the promoters were found to be similar in cell lines and in adult zebrafish. GFP fluorescence in tissues after electroporation was also studied by fluorescence microscopy.

Conclusion
Electroporation after DNA injection enhances gene expression 10-fold in adult zebrafish. Electroporation parameters for optimum transfection of adult zebrafish with tweezer type electrode were presented. Enhanced reporter gene expression upon electroporation allowed comparison of strengths of the promoters in vivo in zebrafish.
Monitoring of minimal residual disease in acute myeloid leukemia Monitorisierung minimaler Resterkrankung bei akuter myeloischer Leukämie
Authors: Kern Wolfgang , Schnittger Susanne 
Published: October 2005

Abstract
Monitoring minimal residual disease (MRD) becomes increasingly important in the risk-adapted management of patients with acute myeloid leukemia (AML). The two most sensitive and also quantitative methods for MRD detection are multiparameter flow cytometry (MFC) and real-time PCR (QRT-PCR). Fusion gene-specific PCR in AML is based on the RNA level while MFC evaluates MRD levels based on cell counts. Both methods have been demonstrated to independently impact the patients' prognosis. The strong power of MFC has been shown mainly in the assessment of early clearance of the malignant clone. MRD levels in AML with fusion genes have the strongest prognostic power after the end of consolidation therapy. In addition, with QRT-PCR, highly predictive initial expression levels can be assessed. With both methods, early detection of relapse is possible. Today, validated PCR-based MRD is being done not only with fusion genes that are detectable in only 20–25% of all AML, but also with new molecular markers like FLT3-mutations, NPM-mutations, MLL-PTD, WT1, and EVI1 expression. Thus, in 80–90% of all AML, a marker for PCR is available that can be detected with a sensitivity of 1:10,000 to 1:1,000,000. In contrast, MFC based MRD quantification is possible in nearly 100% of all AML. However, in some cases the sensitivity is somewhat lower than with PCR. Large clinical trials will determine the role and place of immunologic and PCR-based monitoring in the prognostic stratification of patients with AML.
Heterogeneity in physicochemical properties explains differences in silver toxicity amelioration by natural organic matter to Daphnia magna
Authors: Glover Chris N. , Sharma Sonia K. , Wood Chris M. 
Published: October 2005

Abstract
Recently collected data have shown that natural organic matter (NOM) source is an important parameter influencing the toxicity of silver to the freshwater crustacean Daphnia magna. The present study attempted to correlate the physicochemical properties of 11 naturally isolated and commercially available NOM sources with their ameliorative effects. The protection offered by these samples was standardized to the protective effect of Aldrich humic acid using geochemical modeling approaches that accounted for associated changes in water chemistry and, consequently, silver speciation. The protective ability of NOM was not correlated with reactive sulfide or nitrogen content, which are considered to be strong silver-binding ligands. Color (specific absorbance coefficient) was positively correlated with protection but narrowly eluded statistical significance. The peak wavelength of emission fluorescence following excitation at 370 nm and the fluorescence index values of NOM samples were significantly correlated with protective effects, suggesting that aromatic carbon content may govern the ameliorative actions of NOM. Simple optical properties may therefore act as a suitable indicator for the ability of a given NOM to protect against waterborne silver toxicity to D. magna as long as changes in water chemistry and, thus, silver speciation, are considered.
Enantiomeric fractions of chiral polychlorinated biphenyls provide insights on biotransformation capacity of arctic biota
Authors: Warner Nicholas A. , Norstrom Ross J. , Wong Charles S. , Fisk Aaron T. 
Published: October 2005

Abstract
Chiral polychlorinated biphenyls (PCBs) were measured in an arctic marine food web from the Northwater Polynya (NOW) in the Canadian Arctic to examine potential biotransformation of chiral PCB atropisomers. Organisms under investigation included pelagic zooplankton, Arctic cod (Boreogadus saida), seabirds, and ringed seals (Phoca hispida). Previous studies using achiral methods (e.g., biomagnification factors) have shown that chiral PCB congeners biomagnified in the NOW food web, but provided little information about biotransformation of PCBs except in extreme cases (i.e., high biotransformation). In this study, highly nonracemic enantiomeric fractions (EFs) were observed in several seabird species and ringed seals, but racemic EFs were found in prey (zooplankton and fish). This suggests stereoselective and species-specific biotransformation of individual PCB stereoisomers by birds and mammals. These results are consistent with previously reported biotransformation activity of chiral organochlorine pesticides, α-hexachlorocyclohexane, and chlordane within these organisms. This study demonstrates the utility of using chiral analysis of PCBs to investigate biotransformation within biota of arctic food webs.