Non-Ossicular Signal Transmission in Human Middle Ears: Experimental Assessment of the Acoustic Route with Perforated Tympanic Membranes

Direct acoustic stimulation of the cochlea by the sound-pressure difference between the oval and round windows (called the acoustic route ) has been thought to contribute to hearing in some pathological conditions, along with the normally dominant ossicular route. To determine the efficacy of this acoustic route and its constituent mechanisms in human ears, sound pressures were measured at three locations in cadaveric temporal bones [with intact and perforated tympanic membranes (TMs)]: (1) in the external ear canal lateral to the TM, PTM; (2) in the tympanic cavity lateral to the oval window, POW; and (3) near the round window, PRW. Sound transmission via the acoustic route is described by two concatenated processes: (1) coupling of sound pressure from ear canal to middle-ear cavity, H PCAV ≡ PCAV PTM, where PCAV represents the middle-ear cavity pressure, and (2) sound-pressure difference between the windows, HWPD ≡ (POW - PRW) PCAV. Results show that: H PCAV depends on perforation size but not perforation location; HWPD depends on neither perforation size nor location. The results (1) provide a description of the window pressures based on measurements, (2) refute the common otological view that TM perforation location affects the relative phase of the pressures at the oval and round windows, and (3) show with an intact ossicular chain that acoustic-route transmission is substantially below ossicular-route transmission except for low frequencies with large perforations. Thus, hearing loss from TM perforations results primarily from reduction in sound coupling via the ossicular route. Some features of the frequency dependence of H PCAV and HWPD can be interpreted in terms of a structure-based lumped-element acoustic model of the perforation and middle-ear cavities

Middle-Ear Function with Tympanic-Membrane Perforations. II. A Simple Model.

A quantitative model of the human middle ear with a tympanic-membrane ~TM! perforation is developed. The model is constrained by several types of acoustic measurements made on human cadaver ears, which indicate that perforation-induced changes in transmission result primarily from changes in driving pressure across the TM and that perforation-induced change in the structure of the TM and its coupling to the ossicles contributes a substantially smaller component. The model represents the effect of a perforation on the pressure difference across the TM by inclusion of a path for sound coupling through the perforation from the ear canal to the middle-ear cavity. The model implies that hearing loss with perforations depends primarily on three quantities: the perforation diameter, sound frequency, and the volume of air in the middle-ear cavity. For the conditions that produce the largest hearing loss ~low frequency and large perforation!, the model yields a simple dependence of loss on frequency, perforation diameter, and middle-ear cavity volume. Predictions from this model may be useful to clinicians in determining whether, in particular cases, hearing losses are explainable by the observed perforations or if additional pathology must be involved

Middle-Ear Function with Tympanic-Membrane Perforations. I. Measurements and Mechanisms

Sound transmission through ears with tympanic-membrane ~TM! perforations is not well understood. Here, measurements on human-cadaver ears are reported that describe sound transmission through the middle ear with experimentally produced perforations, which range from 0.5 to 5.0 mm in diameter. Three response variables were measured with acoustic stimulation at the TM: stapes velocity, middle-ear cavity sound pressure, and acoustic impedance at the TM. The stapes-velocity measurements show that perforations cause frequency-dependent losses; at low frequencies losses are largest and increase as perforation size increases. Measurements of middle-ear cavity pressure coupled with the stapes-velocity measurements indicate that the dominant mechanism for loss with TM perforations is reduction in pressure difference across the TM; changes in TM-to-ossicular coupling generally contribute less than 5 dB to the loss. Measurements of middle-ear input impedance indicate that for low frequencies, the input impedance with a perforation approximates the impedance of the middle-ear cavity; as the perforation size increases, the similarity to the cavity’s impedance extends to higher frequencies. The collection of results suggests that the effects of perforations can be represented by the path for air-volume flow from the ear canal to the middle-ear cavity. The quantitative description of perforation-induced losses may help clinicians determine, in an ear with a perforation, whether poor hearing results only from the perforation or whether other pathology should be expected

Physical activity attenuates the mid-adolescent peak in insulin resistance but by late adolescence the effect is lost: a longitudinal study with annual measures from 9-16 years (EarlyBird 66)

The final publication is available at Springer via http://dx.doi.org/10.1007/s00125-015-3714-5There is another ORE record for this publication: http://hdl.handle.net/10871/34546AIMS/HYPOTHESIS: The aim of this work was to test whether the mid-adolescent peak in insulin resistance (IR) and trends in other metabolic markers are influenced by long-term exposure to physical activity. METHODS: Physical activity (7 day ActiGraph accelerometry), HOMA-IR and other metabolic markers (glucose, fasting insulin, HbA1c, lipids and BP) were measured annually from age 9 years to 16 years in 300 children (151 boys) from the EarlyBird study in Plymouth, UK. The activity level of each child was characterised, with 95% reliability, by averaging their eight annual physical activity measures. Age-related trends in IR and metabolic health were analysed by multi-level modelling, with physical activity as the exposure measure (categorical and continuous) and body fat percentage (assessed by dual-energy X-ray absorptiometry) and pubertal status (according to age at peak height velocity and Tanner stage) as covariates. RESULTS: The peak in IR at age 12-13 years was 17% lower (p < 0.001) in the more active adolescents independently of body fat percentage and pubertal status. However, this difference diminished progressively over the next 3 years and had disappeared completely by the age of 16 years (e.g. difference was -14% at 14 years, -8% at 15 years and +1% at 16 years; 'physical activity × age(2)' interaction, p < 0.01). Triacylglycerol levels in girls (-9.7%, p = 0.05) and diastolic blood pressure in boys (-1.20 mmHg, p = 0.03) tended to be lower throughout adolescence in the more active group. CONCLUSIONS/INTERPRETATION: Our finding that physical activity attenuates IR during mid-adolescence may be clinically important. It remains to be established whether the temporary attenuation in IR during this period has implications for the development of diabetes in adolescence and for future metabolic health generally.Bright Future TrustKirby Laing FoundationPeninsula FoundationEarlyBird Diabetes TrustNational Institute for Health Research (NIHR) Collaborations for Leadership in Applied Health Research and Care (CLAHRC

Time-dependent ARMA modeling of genomic sequences

<p>Abstract</p> <p>Background</p> <p>Over the past decade, many investigators have used sophisticated time series tools for the analysis of genomic sequences. Specifically, the correlation of the nucleotide chain has been studied by examining the properties of the power spectrum. The main limitation of the power spectrum is that it is restricted to stationary time series. However, it has been observed over the past decade that genomic sequences exhibit non-stationary statistical behavior. Standard statistical tests have been used to verify that the genomic sequences are indeed not stationary. More recent analysis of genomic data has relied on time-varying power spectral methods to capture the statistical characteristics of genomic sequences. Techniques such as the evolutionary spectrum and evolutionary periodogram have been successful in extracting the time-varying correlation structure. The main difficulty in using time-varying spectral methods is that they are extremely unstable. Large deviations in the correlation structure results from very minor perturbations in the genomic data and experimental procedure. A fundamental new approach is needed in order to provide a stable platform for the non-stationary statistical analysis of genomic sequences.</p> <p>Results</p> <p>In this paper, we propose to model non-stationary genomic sequences by a time-dependent autoregressive moving average (TD-ARMA) process. The model is based on a classical ARMA process whose coefficients are allowed to vary with time. A series expansion of the time-varying coefficients is used to form a generalized Yule-Walker-type system of equations. A recursive least-squares algorithm is subsequently used to estimate the time-dependent coefficients of the model. The non-stationary parameters estimated are used as a basis for statistical inference and biophysical interpretation of genomic data. In particular, we rely on the TD-ARMA model of genomic sequences to investigate the statistical properties and differentiate between coding and non-coding regions in the nucleotide chain. Specifically, we define a quantitative measure of randomness to assess how far a process deviates from white noise. Our simulation results on various gene sequences show that both the coding and non-coding regions are non-random. However, coding sequences are "whiter" than non-coding sequences as attested by a higher index of randomness.</p> <p>Conclusion</p> <p>We demonstrate that the proposed TD-ARMA model can be used to provide a stable time series tool for the analysis of non-stationary genomic sequences. The estimated time-varying coefficients are used to define an index of randomness, in order to assess the statistical correlations in coding and non-coding DNA sequences. It turns out that the statistical differences between coding and non-coding sequences are more subtle than previously thought using stationary analysis tools: Both coding and non-coding sequences exhibit statistical correlations, with the coding regions being "whiter" than the non-coding regions. These results corroborate the evolutionary periodogram analysis of genomic sequences and revoke the stationary analysis' conclusion that coding DNA behaves like random sequences.</p

“Extreme" porn? The implications of a label

Despite its prevalence, the term ‘extreme’ has received little critical attention. ‘Extremity’ is routinely employed in ways that imply its meanings are self-evident. However, the adjective itself offers no such clarity. This article focuses on one particular use of the term – ‘extreme porn’ – in order to illustrate a broader set of concerns about the pitfalls of labelling. The label ‘extreme’ is typically employed as a substitute for engaging with the term’s supposed referents (here, pornographic content). In its contemporary usage, ‘extreme’ primarily refers to a set of context-dependent judgements rather than absolute standards or any specific properties the ‘extreme’ item is alleged to have. Concurrently then, the label ‘extreme’ carries a host of implicit values, and the presumption that the term’s meanings are ‘obvious’ obfuscates those values. In the case of ‘extreme porn’, this obfuscation is significant because it has facilitated the cultural and legal suppression of pornography

Measurement of Jet Shapes in Photoproduction at HERA

The shape of jets produced in quasi-real photon-proton collisions at centre-of-mass energies in the range $134-277$ GeV has been measured using the hadronic energy flow. The measurement was done with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the $\eta - \phi$ plane with a cone radius of one unit. Measured jet shapes both in inclusive jet and dijet production with transverse energies $E^{jet}_T>14$ GeV are presented. The jet shape broadens as the jet pseudorapidity ($\eta^{jet}$) increases and narrows as $E^{jet}_T$ increases. In dijet photoproduction, the jet shapes have been measured separately for samples dominated by resolved and by direct processes. Leading-logarithm parton-shower Monte Carlo calculations of resolved and direct processes describe well the measured jet shapes except for the inclusive production of jets with high $\eta^{jet}$ and low $E^{jet}_T$. The observed broadening of the jet shape as $\eta^{jet}$ increases is consistent with the predicted increase in the fraction of final state gluon jets.Comment: 29 pages including 9 figure

Search for the Standard Model Higgs Boson with the OPAL Detector at LEP

This paper summarises the search for the Standard Model Higgs boson in e+e- collisions at centre-of-mass energies up to 209 GeV performed by the OPAL Collaboration at LEP. The consistency of the data with the background hypothesis and various Higgs boson mass hypotheses is examined. No indication of a signal is found in the data and a lower bound of 112.7GeV/C^2 is obtained on the mass of the Standard Model Higgs boson at the 95% CL.Comment: 51 pages, 21 figure

Colour reconnection in e+e- -> W+W- at sqrt(s) = 189 - 209 GeV

The effects of the final state interaction phenomenon known as colour reconnection are investigated at centre-of-mass energies in the range sqrt(s) ~ 189-209 GeV using the OPAL detector at LEP. Colour reconnection is expected to affect observables based on charged particles in hadronic decays of W+W-. Measurements of inclusive charged particle multiplicities, and of their angular distribution with respect to the four jet axes of the events, are used to test models of colour reconnection. The data are found to exclude extreme scenarios of the Sjostrand-Khoze Type I (SK-I) model and are compatible with other models, both with and without colour reconnection effects. In the context of the SK-I model, the best agreement with data is obtained for a reconnection probability of 37%. Assuming no colour reconnection, the charged particle multiplicity in hadronically decaying W bosons is measured to be (nqqch) = 19.38+-0.05(stat.)+-0.08 (syst.).Comment: 30 pages, 9 figures, Submitted to Euro. Phys. J.

Self-prioritization and perceptual matching: The effects of temporal construal.

Recent research has revealed that self-referential processing enhances perceptual judgments - the so-called self-prioritization effect. The extent and origin of this effect remains unknown, however. Noting the multifaceted nature of the self, here we hypothesized that temporal influences on self-construal (i.e., past/future-self continuity) may serve as an important determinant of stimulus prioritization. Specifically, as representations of the self increase in abstraction as a function of temporal distance (i.e., distance from now), self-prioritization may only emerge when stimuli are associated with the current self. The results of three experiments supported this prediction. Self-relevance only enhanced performance in a standard perceptual-matching task when stimuli (i.e., geometric shapes) were connected with the current self; representations of the self in the future (Expts. 1 & 2) and past (Expt. 3) failed to facilitate decision making. To identify the processes underlying task performance, data were interrogated using a hierarchical drift diffusion model (HDDM) approach. Results of these analyses revealed that self-prioritization was underpinned by a stimulus bias (i.e., rate of information uptake). Collectively, these findings elucidate when and how self-relevance influences decisional processing