bluuebunny/crossref_metadata_2025 huggingface dataset:
Stabilization ofDll1mRNA by Elavl1/HuR in neuroepithelial cells undergoing mitosis
Authors: García-Domínguez Daniel J. , Morello Dominique , Cisneros Elsa , Kontoyiannis Dimitris L. , Frade José M.
Published: February 2011

In the vertebrate neuroepithelium, the decision to differentiate is made by neural precursors soon after mitosis, when they are apically located. This process is controlled by lateral inhibitory signals triggered by the Delta/Notch pathway. During mitosis, the capacity of neural precursors to express the neurogenic genes Dll1 and Notch1 is maximal due to mRNA stabilization, but the mechanism controlling this process remains unknown. Here we show that Elav-like (Elavl1)/HuR becomes enriched in the cytoplasm of neuroepithelial cells undergoing mitosis and that this ribonucleoprotein interacts with the 3′ untranslated region (UTR) of Dll1 mRNA. This interaction is functionally relevant because RNAi against Elavl1 reduces the stability of Dll1–3′UTR-containing transcripts in mitosis-arrested neuroepithelial cells, and Elavl1 null-mutant heterozygous mice show decreased Dll1 expression in the developing brain in vivo. We also show that RNAi against Elavl1 diminishes the capacity of brain precursors to trigger lateral inhibitory signals to their neighbors, an observation consistent with the increase in the rate of neurogenesis which can be detected in vivo in the developing retina of Elavl1 heterozygous mice. We conclude that Elavl1/HuR facilitates the exposure of vertebrate neuronal precursors to apically located Delta/Notch signals.
Mitotic centromeric targeting of HP1 and its binding to Sgo1 are dispensable for sister-chromatid cohesion in human cells
Authors: Kang Jungseog , Chaudhary Jaideep , Dong Hui , Kim Soonjoung , Brautigam Chad A. , Yu Hongtao
Published: February 2011

Human Shugoshin 1 (Sgo1) protects centromeric sister-chromatid cohesion during prophase and prevents premature sister-chromatid separation. Heterochromatin protein 1 (HP1) has been proposed to protect centromeric sister-chromatid cohesion by directly targeting Sgo1 to centromeres in mitosis. Here we show that HP1α is targeted to mitotic centromeres by INCENP, a subunit of the chromosome passenger complex (CPC). Biochemical and structural studies show that both HP1–INCENP and HP1–Sgo1 interactions require the binding of the HP1 chromo shadow domain to PXVXL/I motifs in INCENP or Sgo1, suggesting that the INCENP-bound, centromeric HP1α is incapable of recruiting Sgo1. Consistently, a Sgo1 mutant deficient in HP1 binding is functional in centromeric cohesion protection and localizes normally to centromeres in mitosis. By contrast, INCENP or Sgo1 mutants deficient in HP1 binding fail to localize to centromeres in interphase. Therefore, our results suggest that HP1 binding by INCENP or Sgo1 is dispensable for centromeric cohesion protection during mitosis of human cells, but might regulate yet uncharacterized interphase functions of CPC or Sgo1 at the centromeres.
Enzymatic Activity of the Soybean Ecto-Apyrase GS52 Is Essential for Stimulation of Nodulation
Authors: Tanaka Kiwamu , Nguyen Cuong T. , Libault Marc , Cheng Jianlin , Stacey Gary
Published: February 2011

Nitrogen is an essential nutrient for plant growth. In the Rhizobium-legume symbiosis, root nodules are the sites of bacterial nitrogen fixation, in which atmospheric nitrogen is converted into a form that plants can utilize. While recent studies suggested an important role for the soybean (Glycine max) ecto-apyrase GS52 in rhizobial root hair infection and root nodule formation, precisely how this protein impacts the nodulation process remains undetermined. In this study, the biochemical characteristics of the GS52 enzyme were investigated. Computer modeling of the GS52 apyrase structure identified key amino acid residues important for catalytic activity, which were subsequently mutagenized. Although the GS52 enzyme exhibited broad substrate specificity, its activity on pyrimidine nucleotides and diphosphate nucleotides was significantly higher than on ATP. This result was corroborated by structural modeling of GS52, which predicted a low specificity for the adenine base within the substrate-binding pocket of the enzyme. The wild-type enzyme and its inactive mutant forms were expressed in soybean roots in order to evaluate the importance of GS52 enzymatic activity for nodulation. The results indicated a clear correlation between GS52 enzymatic activity and nodule number. Altogether, our study indicates that the catalytic activity of the GS52 apyrase, likely acting on extracellular nucleotides, is critical for rhizobial infection and nodulation.
Genetic and Genomic Evidence That Sucrose Is a Global Regulator of Plant Responses to Phosphate Starvation in Arabidopsis
Authors: Lei Mingguang , Liu Yidan , Zhang Baocai , Zhao Yingtao , Wang Xiujie , Zhou Yihua , Raghothama Kashchandra G. , Liu Dong
Published: February 2011

Plants respond to phosphate (Pi) starvation by exhibiting a suite of developmental, biochemical, and physiological changes to cope with this nutritional stress. To understand the molecular mechanism underlying these responses, we isolated an Arabidopsis (Arabidopsis thaliana) mutant, hypersensitive to phosphate starvation1 (hps1), which has enhanced sensitivity in almost all aspects of plant responses to Pi starvation. Molecular and genetic analyses indicated that the mutant phenotype is caused by overexpression of the SUCROSE TRANSPORTER2 (SUC2) gene. As a consequence, hps1 has a high level of sucrose (Suc) in both its shoot and root tissues. Overexpression of SUC2 or its closely related family members SUC1 and SUC5 in wild-type plants recapitulates the phenotype of hps1. In contrast, the disruption of SUC2 functions greatly inhibits plant responses to Pi starvation. Microarray analysis further indicated that 73% of the genes that are induced by Pi starvation in wild-type plants can be induced by elevated levels of Suc in hps1 mutants, even when they are grown under Pi-sufficient conditions. These genes include several important Pi signaling components and those that are directly involved in Pi transport, mobilization, and distribution between shoot and root. Interestingly, Suc and low-Pi signals appear to interact with each other both synergistically and antagonistically in regulating gene expression. Our genetic and genomic studies provide compelling evidence that Suc is a global regulator of plant responses to Pi starvation. This finding will help to further elucidate the signaling mechanism that controls plant responses to this particular nutritional stress.
Ageing hospital nurses’ well‐being at work: psychometric testing of the Dignity and Respect in Ageing Nurses’ Work Scale
Authors: Utriainen Kati , Kyngäs Helvi
Published: February 2011

Scand J Caring Sci; 2011; 25; 617–624
 
Ageing hospital nurses’ well‐being at work: psychometric testing of the Dignity and Respect in Ageing Nurses’ Work Scale

Valid and reliable methods to measure nurses’ well‐being at work as a positive phenomenon are needed. Factors promoting well‐being at work need to be identified, which would enable targeting interventions and development in nursing work in an appropriate manner. Due to dissimilarity of many areas of nursing work and unique features of every age group, specialized and aligned scales are needed. The aim of this article is to describe a study to develop and test the psychometric properties of the Dignity and Respect in Ageing Nurses’ Work Scale (DRANWS). A sample of 328 ageing Finnish hospital nurses in the first phase (response rate 55%) and 285 nurses in the second phase (response rate 48%) responded to the scale. Content validity was assessed by expert evaluation. Exploratory factor analysis was used to assess construct validity. Reliability (internal consistency) was assessed by Cronbach’s alpha coefficient. The DRANWS consists of 72 items and three dimensions: (1) nurse–nurse interaction (cohesion, feeling of freedom in work community, giving and receiving assistance and support, nurses’ status at work, perceiving one’s work as meaningful, being together with other nurses, nurses working in pairs), (2) nurse–patient interaction (patient satisfaction, well‐conducted nursing, encountering patients and helping them) and (3) nursing‐centredness (provision of good care to patients, putting the patient first, appreciation of nursing). Cronbach’s alphas ranged from 0.74 to 0.96 in the first phase and from 0.79 to 0.98 in the second phase, demonstrating the internal consistency of scale to be high. Content validity was good based on expert evaluations. Construct validity of the scale was also very good based on factor analysis. In conclusion, the DRANWS is a reliable and valid scale to measure well‐being at work of ageing hospital nurses focusing on dignity and respect.
Formal Infrastructure and Ethical Decision Making: An Empirical Investigation and Implications for Supply Management
Authors: Rottig Daniel , Koufteros Xenophon , Umphress Elizabeth
Published: February 2011

Building on Rest's (1986) conceptual model of ethical decision making, we derive and empirically test a model that links an organization's formal ethical infrastructure to individuals’ moral awareness of ethical situations, moral judgment, and moral intention. We contribute to the literature by shedding light on the importance of a multifaceted formal ethical infrastructure—consisting of formal communication, recurrent communication, formal surveillance, and formal sanctions—as a crucial antecedent of moral awareness. In so doing, we discern how these four elements of a formal ethical infrastructure combine to collectively influence moral awareness based on a second‐order factor structure using structural equation modeling. We test our model based on survey data from 805 respondents with significant work experience across three separate ethical scenarios. Our results across the three scenarios provide overall support for our model. We found that a second‐order factor structure for the formal ethical infrastructure explains the variance among the four infrastructure elements and that a multifaceted formal ethical infrastructure significantly increases moral awareness. Our results further suggest a strong positive effect of moral awareness on moral judgment, which in turn was found to have a positive impact on moral intention. These results were substantiated when taking several individual and contextual control variables into account, such as gender, age, religiosity, work satisfaction, and a de facto ethical climate. Implications for theory, practice, and supply management are discussed.
Segmentation Opportunities for a Social Planner: Impact of Limited Resources
Authors: Yayla‐Küllü H. Müge , Parlaktürk Ali K. , Swaminathan Jayashankar M.
Published: February 2011

In this research note, we investigate segmentation opportunities for social planners such as government agencies, nonprofits, and public organizations. These opportunities arise when the potential products are vertically (quality) differentiated and the consumers are heterogeneous in their preferences toward quality. In these cases, whether to offer quality differentiated products and what quality level to choose are important decisions for a social planner. In this research note, we identify the conditions where it is socially optimal to offer either one homogenous or two quality differentiated products. We find that the resource limitations may result in a single product offering and that the quality of the product depends on the maximum surplus per unit resource consumed by the products. We also compare our findings to a profit‐maximizing firm. We find that the resource limitations may cause a profit‐maximizing firm to provide a better service to some consumers than the social planner. Contrary to common wisdom, we also show that the capacity limitations may force the social planner to act like a profit‐maximizing firm in terms of its pricing and product mix choice.
An Advanced Power-Generation System With CO2 Recovery Integrating DME Fueled Chemical-Looping Combustion
Authors: Han Tao , Hong Hui , Jin Hongguang , Zhang Chuanqiang
Published: February 2011

Dimethyl ether (DME) is a promising alternative fuel, but direct combustion of DME will result in extra energy penalty for CO2 separation. In this paper, an advanced power-generation system with CO2 recovery integrating DME fueled chemical-looping combustion is proposed. In the reduction reactor, DME is oxidized by Fe2O3 into CO2 and H2O, and Fe2O3 is reduced into FeO simultaneously. Since the endothermic reduction in Fe2O3 with DME requires relatively low-grade thermal energy around 180°C, waste heat is used to provide the reaction heat. FeO is oxidized into Fe2O3 by air in the oxidation reactor, producing high-temperature flue gas to generate electricity through a thermal cycle. The gas production from the fuel reactor only consists of CO2 and H2O, so CO2 can be easily separated through condensing with no extra energy penalty. As a result, the thermal efficiency could be expected to be 58.6% at a turbine inlet temperature of 1288°C. This proposed system may provide a new approach for high efficient use of DME in the industrial fields, and offer a possibility of chemical-looping combustion with inherent CO2 capture for the alternative fuel.
Heat Transfer in Hot Pressing of Saturated Fiber Suspensions
Authors: Khiabani Reza H. , Joshi Yogendra , Aidun Cyrus K.
Published: February 2011

This paper presents a three-dimensional numerical framework based on lattice Boltzman method combined with the energy equation for predicting the thermal properties of saturated fiber networks. Heat transfer in fiber suspensions during hot pressing in paper making process is investigated. The effects of efficient preheating on overall energy savings are discussed. The accuracy of the analytical solution based on the assumption of semi-infinite solid body is also investigated. The results show that the thermal properties change significantly depending on the wood fiber types. The effective thermal conductivities of fiber suspensions for three different fiber types are calculated. The predictions compare well with existing experimental and analytical data.
Separability of prosodic phrase boundary and phonemic information
Authors: Nakai Satsuki , Turk Alice E.
Published: February 2011

It was hypothesized that the retrieval of prosodic and phonemic information from the acoustic signal is facilitated when prosodic information is encoded by co-occurring suprasegmental cues. To test the hypothesis, two-choice speeded classification experiments were conducted, which examined processing interaction between prosodic phrase-boundary vs stop-place information in speakers of Southern British English. Results confirmed that the degree of interaction between boundary and stop-place information diminished when the pre-boundary vowel was signaled by duration and F0, compared to when it was signaled by either duration or F0 alone. It is argued that the relative ease of retrieval of prosodic and phonemic information arose from advantages of prosodic cue integration.
Effects of non-simultaneous masking on the binaural masking level difference
Authors: Buss Emily , Hall III Joseph W.
Published: February 2011

The present study sought to clarify the role of non-simultaneous masking in the binaural masking level difference for maskers that fluctuate in level. In the first experiment the signal was a brief 500-Hz tone, and the masker was a bandpass noise (100–2000 Hz), with the initial and final 200-ms bursts presented at 40-dB spectrum level and the inter-burst gap presented at 20-dB spectrum level. Temporal windows were fitted to thresholds measured for a range of gap durations and signal positions within the gap. In the second experiment, individual differences in out of phase (NoSπ) thresholds were compared for a brief signal in a gapped bandpass masker, a brief signal in a steady bandpass masker, and a long signal in a narrowband (50-Hz-wide) noise masker. The third experiment measured brief tone detection thresholds in forward, simultaneous, and backward masking conditions for a 50- and for a 1900-Hz-wide noise masker centered on the 500-Hz signal frequency. Results are consistent with comparable temporal resolution in the in phase (NoSo) and NoSπ conditions and no effect of temporal resolution on individual observers’ ability to utilize binaural cues in narrowband noise. The large masking release observed for a narrowband noise masker may be due to binaural masking release from non-simultaneous, informational masking.
Nonlinear propagation delay and pulse distortion resulting from dual frequency band transmit pulse complexes
Authors: Hansen Rune , Måsøy Svein-Erik , Tangen Thor A. , Angelsen Bjørn A.
Published: February 2011

A method of acoustic imaging is discussed that potentially can improve the diagnostic capabilities of medical ultrasound. The method, given the name second order ultrasound field imaging, is achieved by the processing of the received signals from transmitted dual frequency band pulse complexes with at least partly overlapping high frequency (HF) and low frequency (LF) pulses. The transmitted HF pulses are used for image reconstruction whereas the transmitted LF pulses are used to manipulate the elastic properties of the medium observed by the HF imaging pulses. In the present paper, nonlinear propagation effects observed by a HF imaging pulse due to the presence of a LF manipulation pulse is discussed. When using dual frequency band transmit pulse complexes with a large separation in center frequency (e.g., 1:10), these nonlinear propagation effects are manifested as a nonlinear HF propagation delay and a HF pulse distortion different from conventional harmonic distortion. In addition, with different transmit foci for the HF and LF pulses, nonlinear aberration will occur.
Bayesian characterization of multiple-slope sound energy decays in coupled-volume systems
Authors: Xiang Ning , Goggans Paul , Jasa Tomislav , Robinson Philip
Published: February 2011

Due to recent developments in concert hall design, there is an increasing interest in the analysis of sound energy decays consisting of multiple exponential decay rates. It has been considered challenging to estimate parameters associated with double-rate (slope) decay characteristics, and even more challenging when the coupled-volume systems contain more than two decay processes. To meet the need of characterizing energy decays of multiple decay processes, this work investigates coupled-volume systems using acoustic scale-models of three coupled rooms. Two Bayesian formulations are compared using the experimentally measured sound energy decay data. A fully parameterized Bayesian formulation has been found to be capable of characterization of multiple-slope decays beyond the single-slope and double-slope energy decays. Within the Bayesian framework using this fully parameterized formulation, an in-depth analysis of likelihood distributions over multiple-dimensional decay parameter space motivates the use of Bayesian information criterion, an efficient approach to solving Bayesian model selection problems that are suitable for estimating the number of exponential decays. The analysis methods are then applied to a geometric-acoustics simulation of a conceptual concert hall. Sound energy decays more complicated than single-slope and double-slope nature, such as triple-slope decays have been identified and characterized.
Masking of low-frequency signals by high-frequency, high-level narrow bands of noise
Authors: Patra Harisadhan , Roup Christina M. , Feth Lawrence L.
Published: February 2011

Low-frequency masking by intense high-frequency noise bands, referred to as remote masking (RM), was the first evidence to challenge energy-detection models of signal detection. Its underlying mechanisms remain unknown. RM was measured in five normal-hearing young-adults at 250, 350, 500, and 700 Hz using equal-power, spectrally matched random-phase noise (RPN) and low-noise noise (LNN) narrowband maskers. RM was also measured using equal-power, two-tone complex (TC2) and eight-tone complex (TC8). Maskers were centered at 3000 Hz with one or two equivalent rectangular bandwidths (ERBs). Masker levels varied from 80 to 95 dB sound pressure level in 5 dB steps. LNN produced negligible masking for all conditions. An increase in bandwidth in RPN yielded greater masking over a wider frequency region. Masking for TC2 was limited to 350 and 700 Hz for one ERB but shifted to only 700 Hz for two ERBs. A spread of masking to 500 and 700 Hz was observed for TC8 when the bandwidth was increased from one to two ERBs. Results suggest that high-frequency noise bands at high levels could generate significant low-frequency masking. It is possible that listeners experience significant RM due to the amplification of various competing noises that might have significant implications for speech perception in noise.
Additivity of nonsimultaneous masking for short Gaussian-shaped sinusoids
Authors: Laback Bernhard , Balazs Peter , Necciari Thibaud , Savel Sophie , Ystad Solvi , Meunier Sabine , Kronland-Martinet Richard
Published: February 2011

The additivity of nonsimultaneous masking was studied using Gaussian-shaped tone pulses (referred to as Gaussians) as masker and target stimuli. Combinations of up to four temporally separated Gaussian maskers with an equivalent rectangular bandwidth of 600 Hz and an equivalent rectangular duration of 1.7 ms were tested. Each masker was level-adjusted to produce approximately 8 dB of masking. Excess masking (exceeding linear additivity) was generally stronger than reported in the literature for longer maskers and comparable target levels. A model incorporating a compressive input/output function, followed by a linear summation stage, underestimated excess masking when using an input/output function derived from literature data for longer maskers and comparable target levels. The data could be predicted with a more compressive input/output function. Stronger compression may be explained by assuming that the Gaussian stimuli were too short to evoke the medial olivocochlear reflex (MOCR), whereas for longer maskers tested previously the MOCR caused reduced compression. Overall, the interpretation of the data suggests strong basilar membrane compression for very short stimuli.
Growth of suppression in humans based on distortion-product otoacoustic emission measurements
Authors: Gorga Michael P. , Neely Stephen T. , Kopun Judy , Tan Hongyang
Published: February 2011

Distortion-product otoacoustic emissions (DPOAEs) were used to describe suppression growth in normal-hearing humans. Data were collected at eight f2 frequencies ranging from 0.5 to 8 kHz for L2 levels ranging from 10 to 60 dB sensation level. For each f2 and L2 combination, suppression was measured for nine or eleven suppressor frequencies (f3) whose levels varied from −20 to 85 dB sound pressure level (SPL). Suppression grew nearly linearly when f3 ≈ f2, grew more rapidly for f3 < f2, and grew more slowly for f3 > f2. These results are consistent with physiological and mechanical data from lower animals, as well as previous DPOAE data from humans, although no previous DPOAE study has described suppression growth for as wide a range of frequencies and levels. These trends were evident for all f2 and L2 combinations; however, some exceptions were noted. Specifically, suppression growth rate was less steep as a function of f3 for f2 frequencies ≤1 kHz. Thus, despite the qualitative similarities across frequency, there were quantitative differences related to f2, suggesting that there may be subtle differences in suppression for frequencies above 1 kHz compared to frequencies below 1 kHz.
Echolocation and flight strategy of Japanese house bats during natural foraging, revealed by a microphone array system
Authors: Fujioka Emyo , Mantani Shigeki , Hiryu Shizuko , Riquimaroux Hiroshi , Watanabe Yoshiaki
Published: February 2011

Using only a microphone array system, echolocation pulses and three-dimensional flight paths in the frequency-modulated bat, Pipistrellus abramus, during natural foraging, were simultaneously examined. During the search phase, the inter-pulse interval, pulse duration, and moving distance of the bat between successive emissions were relatively constant at around 89.5 ± 18.7 ms, 6.90 ± 1.31 ms, and 0.50 ± 0.20 m, respectively. The bats started to decrease these acoustical parameters within 2–3 m of the prey capture point. For every emission along a flight path, the distance between a bat and its prey capture point was calculated as both direct distance to capture (DDC), which corresponded to the target distance, and flight distance to capture (FDC) along the flight path. The DDC matched the FDC after the start of the approach phase, indicating that foraging bats followed a straight-ahead path to the target. In addition, the duration of the quasi-constant frequency component of emitted pulses was slightly extended just before the convergence of the DDC with the FDC. These findings suggest that the bats confirm the presence of target prey by extending the duration of the pulse and then select a straight-ahead approach by forecasting the movement of the prey.
Measurement of Lamb wave polarization using a one-dimensional scanning laser vibrometer (L)
Authors: Ayers James , Apetre Nicole , Ruzzene Massimo , Sabra Karim
Published: February 2011

A single head scanning laser Doppler vibrometer is used for the estimation of the polarization of the first symmetric (S0) and antisymmetric (A0) Lamb wave modes. The measurements at two known incidence angles are performed in order to resolve the two components of motion. Filtering in the frequency/wavenumber domain of the response recorded along a scan line separates the contributions from each mode and allows the evaluation of the corresponding elliptical trajectories of particle motion. Comparison between measured and analytically estimated trajectories validates the measurement technique and suggests its application for the development of material characterization and diagnostics tools.
Neural time and movement time in choice of whistle or pulse burst responses to different auditory stimuli by dolphins
Authors: Ridgway Sam H.
Published: February 2011

Echolocating dolphins emit trains of clicks and receive echoes from ocean targets. They often emit each successive ranging click about 20 ms after arrival of the target echo. In echolocation, decisions must be made about the target—fish or fowl, predator or food. In the first test of dolphin auditory decision speed, three bottlenose dolphins (Tursiops truncatus) chose whistle or pulse burst responses to different auditory stimuli randomly presented without warning in rapid succession under computer control. The animals were trained to hold pressure catheters in the nasal cavity so that pressure increases required for sound production could be used to split response time (RT) into neural time and movement time. Mean RT in the youngest and fastest dolphin ranged from 175 to 213 ms when responding to tones and from 213 to 275 ms responding to pulse trains. The fastest neural times and movement times were around 60 ms. The results suggest that echolocating dolphins tune to a rhythm so that succeeding pulses in a train are produced about 20 ms over target round-trip travel time. The dolphin nervous system has evolved for rapid processing of acoustic stimuli to accommodate for the more rapid sound speed in water compared to air.
Measurement of the resistivity of porous materials with an alternating air-flow method
Authors: Dragonetti Raffaele , Ianniello Carmine , Romano Rosario A.
Published: February 2011

Air-flow resistivity is a main parameter governing the acoustic behavior of porous materials for sound absorption. The international standard ISO 9053 specifies two different methods to measure the air-flow resistivity, namely a steady-state air-flow method and an alternating air-flow method. The latter is realized by the measurement of the sound pressure at 2 Hz in a small rigid volume closed partially by the test sample. This cavity is excited with a known volume-velocity sound source implemented often with a motor-driven piston oscillating with prescribed area and displacement magnitude. Measurements at 2 Hz require special instrumentation and care. The authors suggest an alternating air-flow method based on the ratio of sound pressures measured at frequencies higher than 2 Hz inside two cavities coupled through a conventional loudspeaker. The basic method showed that the imaginary part of the sound pressure ratio is useful for the evaluation of the air-flow resistance. Criteria are discussed about the choice of a frequency range suitable to perform simplified calculations with respect to the basic method. These criteria depend on the sample thickness, its nonacoustic parameters, and the measurement apparatus as well. The proposed measurement method was tested successfully with various types of acoustic materials.
Auditory filter shapes and high-frequency hearing in adults who have impaired speech in noise performance despite clinically normal audiograms
Authors: Badri Rohima , Siegel Jonathan H. , Wright Beverly A.
Published: February 2011

Some individuals complain of hearing difficulties in the presence of background noise even in the absence of clinically significant hearing loss (obscure auditory dysfunction). Previous evidence suggests that these listeners have impaired frequency resolution, but there has been no thorough characterization of auditory filter shapes in this population. Here, the filter shapes of adults (n = 14) who self-reported speech recognition problems in noise and performed poorly on a sentence-in-noise perception test despite having clinically normal audiograms were compared to those of controls (n = 10). The filter shapes were evaluated using a 2-kHz probe with a fixed level of 30, 40, or 50 dB sound pressure level (SPL) and notched-noise simultaneous maskers that were varied in level to determine the masker level necessary to just mask the probe. The filters of the impaired group were significantly wider than those of controls at all probe levels owing to an unusual broadening of the upper slope of the filter. In addition, absolute thresholds were statistically indistinguishable between the groups at the standard audiometric frequencies, but were elevated in the impaired listeners at higher frequencies. These results strengthen the idea that this population has a variety of hearing deficits that go undetected by standard audiometry.
Divergence of a stereotyped call in northern resident killer whales
Authors: Grebner Dawn M. , Parks Susan E. , Bradley David L. , Miksis-Olds Jennifer L. , Capone Dean E. , Ford John K. B.
Published: February 2011

Northern resident killer whale pods (Orcinus orca) have distinctive stereotyped pulsed call repertoires that can be used to distinguish groups acoustically. Repertoires are generally stable, with the same call types comprising the repertoire of a given pod over a period of years to decades. Previous studies have shown that some discrete pulsed calls can be subdivided into variants or subtypes. This study suggests that new stereotyped calls may result from the gradual modification of existing call types through subtypes. Vocalizations of individuals and small groups of killer whales were collected using a bottom-mounted hydrophone array in Johnstone Strait, British Columbia in 2006 and 2007. Discriminant analysis of slope variations of a predominant call type, N4, revealed the presence of four distinct call subtypes. Similar to previous studies, there was a divergence of the N4 call between members of different matrilines of the same pod. However, this study reveals that individual killer whales produced multiple subtypes of the N4 call, indicating that divergence in the N4 call is not the result of individual differences, but rather may indicate the gradual evolution of a new stereotyped call.
Auditory evoked potentials in two short-finned pilot whales (Globicephala macrorhynchus)
Authors: Schlundt Carolyn E. , Dear Randall L. , Houser Dorian S. , Bowles Ann E. , Reidarson Tom , Finneran James J.
Published: February 2011

The hearing sensitivities of two short-finned pilot whales (Globicephala macrorhynchus) were investigated by measuring auditory evoked potentials generated in response to clicks and sinusoidal amplitude modulated (SAM) tones. The first whale tested, an adult female, was a long-time resident at SeaWorld San Diego with a known health history. Click-evoked responses in this animal were similar to those measured in other echolocating odontocetes. Auditory thresholds were comparable to dolphins of similar age determined with similar evoked potential methods. The region of best sensitivity was near 40 kHz and the upper limit of functional hearing was between 80 and 100 kHz. The second whale tested, a juvenile male, was recently stranded and deemed non-releasable. Click-evoked potentials were not detected in this animal and testing with SAM tones suggested severe hearing loss above 10 kHz.
Probing the independence of formant control using altered auditory feedback
Authors: MacDonald Ewen N. , Purcell David W. , Munhall Kevin G.
Published: February 2011

Two auditory feedback perturbation experiments were conducted to examine the nature of control of the first two formants in vowels. In the first experiment, talkers heard their auditory feedback with either F1 or F2 shifted in frequency. Talkers altered production of the perturbed formant by changing its frequency in the opposite direction to the perturbation but did not produce a correlated alteration of the unperturbed formant. Thus, the motor control system is capable of fine-grained independent control of F1 and F2. In the second experiment, a large meta-analysis was conducted on data from talkers who received feedback where both F1 and F2 had been perturbed. A moderate correlation was found between individual compensations in F1 and F2 suggesting that the control of F1 and F2 is processed in a common manner at some level. While a wide range of individual compensation magnitudes were observed, no significant correlations were found between individuals’ compensations and vowel space differences. Similarly, no significant correlations were found between individuals’ compensations and variability in normal vowel production. Further, when receiving normal auditory feedback, most of the population exhibited no significant correlation between the natural variation in production of F1 and F2.
Hearing threshold estimation using concurrent measurement of distortion product otoacoustic emissions and auditory steady-state responses
Authors: Rosner Thomas , Kandzia Florian , Oswald Johann A. , Janssen Thomas
Published: February 2011

Both distortion product otoacoustic emissions (DPOAEs) and auditory steady-state responses (ASSRs) provide frequency-specific assessment of hearing. However, each method suffers from some restrictions. Hearing losses above 50 dB HL are not quantifiable using DPOAEs and their performance at frequencies below 1 kHz is limited, but their recording time is short. In contrast, ASSRs are a time-consuming method but have the ability to determine hearing thresholds in a wider range of frequencies and hearing losses. Thus, recording DPOAEs and ASSRs simultaneously at their adequate frequencies and levels could decrease the overall test time considerably. The goal of the present study was to develop a parameter-setting and test-protocol to measure DPOAEs and ASSRs binaurally and simultaneously at multiple frequencies. Ten normal-hearing and 23 hearing-impaired subjects participated in the study. The interaction of both responses when stimulated simultaneously at frequencies between 0.25 and 6 kHz was examined. Two limiting factors need to be kept. Frequency distance between ASSR carrier frequency fc and DPOAE primary tone f2 needs to be at least 1.5 octaves, and DPOAEs may not be measured if the ASSR stimulus level is 70 dB SPL or above. There was a significant correlation between pure-tone and DPOAE/ASSR-thresholds in sensorineural hearing loss ears.
Compressive sensing: A strategy for fluttering target discrimination employed by bats emitting broadband calls
Authors: Fontaine Bertrand , Peremans Herbert
Published: February 2011

When foraging, so-called FM-bats emit sequences of frequency modulated (FM) calls in order to detect, identify, and localize edible prey. Once a potential target has been detected, various call and call sequence parameters, such as frequency sweep, pulse duration, and inter pulse interval (IPI) vary. In this paper, the possible functions of the variation of the IPI are studied. In particular, it is conjectured that the IPI patterns are an adaptive behavior that optimizes the signal design parameters in order to improve information retrieval. Such an irregular sampling strategy would be useful whenever bats need to characterize signal modulation (e.g., the wing beat of an insect) using a call emission rate lower than the signal modulation of interest. This problem can be recast as extracting features, in this case the joint acoustic and modulation frequency representation, from signals sampled at frequencies well below the Nyquist cut-off frequency. To study the possibility of such target classification using a sub-Nyquist sampling scheme, results derived in the context of compressive sensing are used. Processing echoes collected from both rotating computer fans and fluttering locusts, it is shown that such a strategy would allow FM-bats to discriminate between targets based on their different fluttering rates.
Translation-Independent Localization of mRNA in
E. coli
Authors: Nevo-Dinur Keren , Nussbaum-Shochat Anat , Ben-Yehuda Sigal , Amster-Choder Orna
Published: February 2011

Sequences within messenger RNAs target them to sites in the bacterial cell where the resulting proteins function.
The Genome Dances
Authors: Lerman Liz
Published: February 2011

The genome has spurred interactions between scientists and artists to bring personal voice to this most human of topics
Presenting the Human Genome: Now in 3D!
Authors: Ruan Yijun
Published: February 2011

Because linear information alone cannot explain function we now need to analyze the genome in multiple dimensions
Systems Genetics
Authors: Nadeau Joseph H. , Dudley Aimée M.
Published: February 2011

Systems genetics is the next frontier in systems biology and medicine.
A Healthy Son
Authors: King Mary-Claire
Published: February 2011

By means of the insights of genetics and the tools of genomics, we are moving towards grappling with inherited genetic disorders.
Evaluation of Widely Used Diagnostic Tests To Detect West Nile Virus Infections in Horses Previously Infected with St. Louis Encephalitis Virus or Dengue Virus Type 2
Authors: Ledermann Jeremy P. , Lorono-Pino Maria A. , Ellis Christine , Saxton-Shaw Kali D. , Blitvich Bradley J. , Beaty Barry J. , Bowen Richard A. , Powers Ann M.
Published: February 2011

Primary West Nile virus (WNV) infections can be diagnosed using a number of tests that detect infectious particles, nucleic acid, and specific IgM and/or IgG antibodies. However, serological identification of the infecting agent in secondary or subsequent flavivirus infections is problematic due to the extensive cross-reactivity of flavivirus antibodies. This is particularly difficult in the tropical Americas where multiple flaviviruses cocirculate. A study of sequential flavivirus infection in horses was undertaken using three medically important flaviviruses and five widely utilized diagnostic assays to determine if WNV infection in horses that had a previous St. Louis encephalitis virus (SLEV) or dengue virus type 2 (DENV-2) infection could be diagnosed. Following the primary inoculation, 25% (3/12) and 75% (3/4) of the horses mounted antibody responses against SLEV and DENV-2, respectively. Eighty-eight percent of horses subsequently inoculated with WNV had a WNV-specific antibody response that could be detected with one of these assays. The plaque reduction neutralization test (PRNT) was sensitive in detection but lacked specificity, especially following repeated flavivirus exposure. The WNV-specific IgM enzyme-linked immunosorbent assay (IgM ELISA) was able to detect an IgM antibody response and was not cross-reactive in a primary SLEV or DENV response. The WNV-specific blocking ELISA was specific, showing positives only following a WNV injection. Of great importance, we demonstrated that timing of sample collection and the need for multiple samples are important, as the infecting etiology could be misdiagnosed if only a single sample is tested.
Seroprevalence of Pandemic 2009 (H1N1) Influenza A Virus among Schoolchildren and Their Parents in Tokyo, Japan
Authors: Iwatsuki-Horimoto Kiyoko , Horimoto Taisuke , Tamura Daisuke , Kiso Maki , Kawakami Eiryo , Hatakeyama Shuji , Ebihara Yasuhiro , Koibuchi Tomohiko , Fujii Takeshi , Takahashi Kazuo , Shimojima Masayuki , Sakai-Tagawa Yuko , Ito Mutsumi , Sakabe Saori , Iwasa Ayaka , Takahashi Kei , Ishii Takashi , Gorai Takeo , Tsuji Koichiro , Iwamoto Aikichi , Kawaoka Yoshihiro
Published: February 2011

Since its emergence, the 2009 pandemic H1N1 virus has spread rapidly throughout the world. Previously, we reported that most individuals born after 1920 do not have cross-reactive virus-neutralizing antibodies against pandemic (H1N1) 2009 virus, indicating that they were immunologically naïve to the pandemic virus prior to its emergence. This finding provided us with an excellent opportunity for a seroepidemiological investigation of the transmission mode of the pandemic virus in the community. To gain insight into its transmission within communities, we performed a serosurvey for pandemic virus infection with schoolchildren at an elementary school in Tokyo, Japan, and their parents. We observed a high prevalence of neutralizing antibodies to the pandemic virus in the children at this school, although the percentage of children positive for the neutralizing antibodies varied among classrooms. While a much lower prevalence was observed among parents, seropositivity of the parents correlated with that of their schoolchildren. Moreover, many adults appeared to have experienced asymptomatic infection with the pandemic virus. These data suggest that the pandemic virus was readily transmitted among schoolchildren in elementary schools and that it was also transmitted from schoolchildren to their parents.
Antigen-Specific Memory B-Cell Responses in Bangladeshi Adults after One- or Two-Dose Oral Killed Cholera Vaccination and Comparison with Responses in Patients with Naturally Acquired Cholera
Authors: Alam Mohammad Murshid , Riyadh M. Asrafuzzaman , Fatema Kaniz , Rahman Mohammad Arif , Akhtar Nayeema , Ahmed Tanvir , Chowdhury Mohiul Islam , Chowdhury Fahima , Calderwood Stephen B. , Harris Jason B. , Ryan Edward T. , Qadri Firdausi
Published: February 2011

The mediators of protective immunity against cholera are currently unknown, but memory B-cell responses may play a central role in facilitating long-term and anamnestic responses againstVibrio cholerae, the cause of cholera. We compared memory B-cell responses in adults with natural cholera in Bangladesh (n= 70) to responses in Bangladeshi adults after one-dose (n= 30) or two-dose (n= 30) administration of an oral killed cholera vaccine, WC-rBS (Dukoral; Crucell), assessing the responses at the acute stage of disease or prevaccination and then on days 3, 30, 90, 180, 270, and 360. Individuals with natural cholera developed prominent vibriocidal and plasma anti-cholera toxin B subunit (CtxB) and lipopolysaccharide (LPS) IgG and IgA responses, but these responses returned to baseline by 1 year of follow-up. Vaccinees developed plasma anti-CtxB and anti-LPS IgG and IgA responses that were generally comparable to those in individuals recovering from natural disease, but vibriocidal responses were lower in vaccinees than in infected patients. Individuals recovering from natural disease developed memory B-cell IgG and IgA anti-CtxB and anti-LPS responses by day 30, and these responses were detectable through at least days 180 to 360. In contrast, we detected no IgA or IgG memory B-cell responses to LPS in vaccinees; anti-CtxB IgA responses were only detectable on day 30, and anti-CtxB IgG responses were detectable until days 90 to 180, compared to days 270 to 360 in patients. These findings may explain in part the relatively short-term protection afforded by oral cholera vaccination compared to natural disease.
Qualitative and Quantitative Analysis of the Binding of GII.4 Norovirus Variants onto Human Blood Group Antigens
Authors: de Rougemont A. , Ruvoen-Clouet N. , Simon B. , Estienney M. , Elie-Caille C. , Aho S. , Pothier P. , Le Pendu J. , Boireau W. , Belliot G.
Published: February 2011

Noroviruses (NoVs) are one of the leading causes of gastroenteritis in children and adults. For the last 2 decades, genogroup II genotype 4 (GII.4) NoVs have been circulating worldwide. GII.4 NoVs can be divided into variants, and since 2002 they have circulated in the population before being replaced every 2 or 3 years, which raises questions about the role of their histo-blood group antigen (HBGA) ligands in their evolution. To shed light on these questions, we performed an analysis of the interaction between representative GII.4 variants and HBGAs, and we determined the role of selected amino acids in the binding profiles. By mutagenesis, we showed that there was a strict structural requirement for the amino acids, directly implicated in interactions with HBGAs. However, the ablation of the threonine residue at position 395 (ΔT395), an epidemiological feature of the post-2002 variants, was not deleterious to the binding of the virus-like particle (VLP) to the H antigen, while binding to A and B antigens was severely hampered. Nevertheless, the ΔT395 VLPs gained the capacity to bind to the Lewis x and sialyl-Lewis x antigens in comparison with the wild-type VLP, demonstrating that amino acid residues outside the HBGA binding site can modify the binding properties of NoVs. We also analyzed the attachment of baculovirus-expressed VLPs from six variants (Bristol, US95/96, Hunter, Yerseke, Den Haag, and Osaka) that were isolated from 1987 to 2007 to phenotyped saliva samples and synthetic HBGAs. We showed that the six variants could all attach to saliva of secretors irrespective of the ABO phenotype and to oligosaccharides characteristic of the secretor phenotype. Interestingly, Den Haag and Osaka variants additionally bound to carbohydrates present in the saliva of Lewis-positive nonsecretors. The carbohydrate binding profile and the genetic and mutagenesis analysis suggested that GII.4 binding to Lewis x and sialyl-Lewis x antigens might be a by-product of the genetic variation of the amino acids located in the vicinity of the binding site. Analysis of the binding properties for the six variants by surface plasmon resonance showed that only post-2002 variants (i.e., Hunter, Yerseke, Den Haag, and Osaka) presented strong binding to A and B antigens, suggesting that the GII.4 evolution could be related to an increased affinity for HBGAs for the post-2002 variants. The combination of increased affinity for ABH antigens and of a newly acquired ability to recognize glycans from Lewis-positive nonsecretors could have contributed to the epidemiological importance of strains such as the Den Haag GII.4 subtype.