bluuebunny/crossref_metadata_2025 huggingface dataset:
Type 2 diabetes mellitus and hypothyroidism: the possible influence of metformin therapy
Authors: Distiller L. A. , Polakow E. S. , Joffe B. I.
Published: October 2013

Aims

To evaluate the frequency with which hypothyroidism is associated with Type 2 diabetes, to examine gender and ethnic group differences, and to assess the possible impact of metformin therapy. To compare the prevalence of hypothyroidism in a cohort of people with Type 2 diabetes with a previously published cohort of people with Type 1 diabetes from the same centre.

Method

We randomly surveyed the records of 922 people with Type 2 diabetes (576 men and 342 women) to identify diagnoses of hypothyroidism, based on current thyroxin replacement therapy (with previous biochemical confirmation). Four subjects had secondary hypothyroidism after radio‐iodine therapy for primary hyperthyroidism and were excluded from the analysis. The prevalence of primary hypothyroidism was documented in the remaining 918 subjects. We assessed the association of metformin therapy with hypothyroidism.

Results

The overall prevalence of primary hypothyroidism was 11.8% (women: 22.5%; men: 5.4%, P < 0.001) in subjects with Type 2 diabetes. Inter‐ethnic differences were noted, with the highest prevalence among white subjects. The prevalence of hypothyroidism was lower in subjects with Type 2 diabetes who were receiving metformin therapy (P < 0.01), and this difference was greater when assessing those who developed primary hypothyroidism after starting metformin therapy (P < 0.001)

Conclusions

Our results support a relatively close association between diabetes and hypothyroidism. Hypothyroidism was more common in the cohort of white subjects than in other ethnic groups. The use of metformin therapy in people with Type 2 diabetes was associated with a significantly lower prevalence of diagnosed hypothyroidism.
Application of temporal difference learning rules in short‐term traffic flow prediction
Authors: Abdi Javad , Moshiri Behzad
Published: October 2013

Studying dynamic behaviours of a transportation system requires the use of the system mathematical models as well as prediction of traffic flow in the system. Therefore, traffic flow prediction plays an important role in today's intelligent transportation systems. This article introduces a new approach to short‐term daily traffic flow prediction based on artificial neural networks. Among the family of neural networks, multi‐layer perceptron (MLP), radial basis function (RBF) neural network and wavenets have been selected as the three best candidates for performing traffic flow prediction. Moreover, back‐propagation (BP) has been adapted as the most efficient learning scheme in all the cases. It is shown that the coefficients produced by temporal signals improve the performance of the BP learning (BPL) algorithm. Temporal signals provide researchers with a new model of temporal difference BP learning algorithm (TDBPL). The capability and performance of TDBPL algorithm are examined by means of simulation in order to prove that the wavelet theory, with its multi‐resolution ability in comparison to RBF neural networks, is a suitable algorithm in traffic flow forecasting. It is also concluded that despite MLP applications, RBF neural networks do not provide negative forecasts. In addition, the local minimum problems are inevitable in MLP algorithms, while RBF neural networks and wavenet networks do not encounter them.
Carotid Intima-Media Thickness – A Potential Predictor for Rupture Risk of Intracranial Aneurysms
Authors: Lundervik Marianne , Fromm Annette , Haaland Øystein Ariansen , Waje-Andreassen Ulrike , Svendsen Frode , Thomassen Lars , Helland Christian A.
Published: October 2013

Background

Individual assessment of rupture risk of cerebral aneurysms is challenging, and increased knowledge of predictors for aneurysm rupture is needed. Smoking and hypertension are shared risk factors for atherosclerotic disease and cerebral aneurysms, and patients with atherosclerosis have an increased prevalence of intracranial aneurysms. Carotid ultrasound with evaluation of intima-media thickness (IMT) is a non-invasive, safe, rapid, well-validated and reproducible technique for quantification of subclinical atherosclerosis and assessment of cardio- and cerebrovascular risk. Increased IMT is associated with elevated risk for ischemic stroke and myocardial infarction, but sparse data exist on carotid ultrasound findings in patients with intracranial aneurysms.

Aims

The purpose of this study was to investigate carotid IMT in patients with unruptured intracranial aneurysms (UIA) and aneurysmal subarachnoid hemorrhage (aSAH), and to assess if IMT might be associated with aneurysm rupture risk.

Methods

Patients treated for saccular aneurysms (UIA and aSAH) from February 2011 to August 2012 were included. Standardized high resolution B-mode ultrasound assessment of carotid arteries was done after aneurysm treatment, and traditional vascular risk factors were recorded. Healthy partners of young patients with ischemic stroke were used as controls.

Results

69 patients treated for UIA ( n = 28) and aSAH ( n = 41) were compared with 80 controls. Mean IMT was higher in patients with aSAH (0·79 mm) than patients with UIA (0·65 mm) and controls (0·63 mm). Multiple multinomial regression analysis comparing aSAH, UIA and control groups demonstrated that IMT was the only variable predicative of aSAH compared to UIA. According to the multiple regression model, the probability of having aSAH compared to non-rupture increased by 62% for each 0·10 mm increment of mean IMT (RRR = 1·62, P = 0·017). Taking into account only patients harboring intracranial aneurysms, simple binary logistic regression was then applied to the UIA and aSAH groups. According to this model the risk of belonging to the aSAH group increased with higher mean IMT values (OR = 1·40 per 0·10 mm increase of mean IMT, P = 0·024).

Conclusion

There is an association between IMT and intracranial aneurysm rupture status at the time of aneurysm treatment. Carotid IMT can be a potential predictor of aneurysm rupture. IMT may thus be a possible adjunct in the risk assessment of aneurysm rupture, and a helpful tool in patient risk stratification and counseling.
Characterization of Warm Saline‐Enhanced Radiofrequency Ablation Lesions in the Infarcted Porcine Ventricular Myocardium
Authors: JOHN ROY M. , CONNELL JOHN , TERMIN PAUL , HOUDE‐WALTER HALEY , EBERL GREGORY , STOHLMAN KATHARINE M. , CURLEY MICHAEL G.
Published: October 2013

Saline Enhanced Radiofrequency Ablation

Background

Radiofrequency (RF) ablation of scar‐mediated ventricular tachycardia is limited by the size of lesions achieved with conventional catheters. We examined the gross and histopathology characteristics of warm saline‐enhanced radiofrequency (SERF) ablation delivered to left ventricular (LV) infarction scars via a novel catheter employing an extendable infusion needle electrode.

Methods and Results

Yorkshire pigs (n = 14) underwent LV infarction by left anterior descending artery balloon occlusion. After 4–6 weeks, baseline hemodynamic data were obtained and endocardial electroanatomic mapping was performed in 13 surviving animals. Following single, 40 Watt SERF ablations delivered endocardially to the center of infarctions, 4 were examined the same day (day 0). The rest underwent repeat measurements and were sacrificed at 1 week (n = 6), and at 4 weeks (n = 3). Average lesion depth and diameter were: 1.85 ± 0.7 cm and 2.33 ± 0.7 cm at day 0, 0.91 ± 0.1 cm and 1.9 ± 0.4 cm after 1 week, and 1.0 ± 0.2 cm and 1.89 ± 0.76 cm after 4 weeks, respectively. Histopathology at 1 week showed that ablation lesions covered 41 ± 10.6% of the infarct area. SERF ablation lesions extended 100%, 90%, and 68% of the total wall thickness at day 0, 1 week, and 4 weeks, respectively. Hemodynamic parameters were unchanged. There were no myocardial wall perforations or aneurysms.

Conclusion

SERF ablation within myocardial infarct tissue produced large, near‐transmural lesions, without evidence of myocardial perforation, wall thinning, or aneurysm formation. Ablations did not produce any negative hemodynamic effects in this small group of experiments.
Electromechanical Effects of 1,25‐Dihydroxyvitamin D with Antiatrial Fibrillation Activities
Authors: HANAFY DICKY A. , CHANG SHIH‐LIN , LU YEN‐YU , CHEN YAO‐CHANG , KAO YU‐HSUN , HUANG JEN‐HUNG , CHEN SHIH‐ANN , CHEN YI‐JEN
Published: October 2013

Electromechanical Effects of 1,25‐Dihydroxyvitamin D on the LA

Introduction

Treatment with 1,25‐dihydroxyvitamin D (1,25[OH]2D) has several cardiovascular benefits. 1,25[OH]2D has direct cellular effects, but its effects on the atrium are not clear. We evaluated the effects of 1,25[OH]2D on the atrial electrophysiology and atrial fibrillation (AF).

Methods

Conventional microelectrodes were used to record action potentials (APs) and contractility in isolated rabbit left atrium (LA) tissue preparations before and after the administration of 0.01, 0.1, and 1 nM 1,25[OH]2D with and without rapid atrial pacing (RAP) and acetylcholine (5 mM)‐induced AF. Surface ECG and intracardiac electrograms were recorded before and after the intravenous administration of 4 units/kg of 1,25[OH]2D in heart failure (HF) rabbits (4 weeks after coronary artery ligation) with RAP and acetylcholine‐induced AF.

Results

1,25[OH]2D dose‐dependently increased the AP duration in the LA, which was abolished by pretreatment with 0.1 μM ryanodine. RAP and 5 mM acetylcholine‐induced fewer (64.3% vs 100%, P < 0.05) AF occurrences in the presence (n = 14) of 1,25[OH]2D than those (n = 14) in the absence of 1,25[OH]2D. The LA treated with 1,25[OH]2D (n = 9) had a slower maximal AF rate (10.9 ± 2.4 Hz vs 13.3 ± 2.7 Hz, P < 0.05) than the LA (n = 14) without 1,25[OH]2D. Moreover, 1,25[OH]2D caused a lower AF inducible percentage (11.0 ± 1.9% vs 100 ± 0%, P < 0.001) and a shorter duration (4 ± 0.4 seconds vs 309 ± 26 seconds, P < 0.001) with a prolonged LA 90% monophasic AP duration (94.1 ± 0.2 milliseconds vs 98.5 ± 0.1 milliseconds, P < 0.05) in 5 rabbits with HF. 1,25[OH]2D did not prolong the QT interval or 90% of the AP duration in isolated Purkinje fibers.

Conclusion

1,25[OH]2D has direct electromechanical effects on the LA and can prevent or terminate AF.
Bankrupt Apologies
Authors: Robbennolt Jennifer K. , Lawless Robert M.
Published: October 2013

Apologies result in better outcomes for wrongdoers in a variety of legal contexts. Previous research, however, has primarily addressed settings in which a clear victim receives the apology. This research uses experimental methods to examine the influence of apologies on a different kind of legal decision—the decision of a bankruptcy judge to confirm or not to confirm a proposed repayment plan. This article expands examination of apologies to a legal setting in which there is no clear “victim” and to decisions of a neutral (nonvictim) decisionmaker. We find that judges' assessments of debtors were influenced by apologies. These assessments, in turn, affected judges' confirmation decisions.
Suing the Leviathan—An Empirical Analysis of the Changing Rate of Administrative Litigation in China
Authors: Li Ji
Published: October 2013

This article analyzes the changing rate of administrative litigation in China. Using a set of provincial‐level data over seven years (2003–2009), the article evaluates a number of hypotheses derived from extant theories of social litigiousness, state‐society relations in authoritarian regimes, Chinese elite politics, and Chinese administrative law. It finds evidence that the rate of administrative litigation varies according to different levels of lawyer density and urbanization. It also finds preliminary evidence that casts doubt on the effects of top‐down legal and policy changes in China. The article is the first longitudinal study of the Chinese administrative litigation system, and it answers questions that have long been underexplored. In addition, the research contributes to our understanding of state‐society relations in authoritarian regimes. This article also evaluates the role of elite politics in the development of the administrative law regime and adds new evidence to the debate about lawyers' role in China's legal reforms. Finally, the article contributes to empirical and comparative studies of litigation rates, especially the less researched area of administrative litigation.
LeCDJ1, a chloroplast DnaJ protein, facilitates heat tolerance in transgenic tomatoes
Authors: Kong Fanying , Deng Yongsheng , Wang Guodong , Wang Jieru , Liang Xiaoqing , Meng Qingwei
Published: October 2013

The roles of a tomato (Lycopersicon esculentum) chloroplast‐targeted DnaJ protein (LeCDJ1) were investigated using wild‐type (WT) and sense transgenic tomatoes. The LeCDJ1 expression was upregulated by 38 °C, 42 °C, 45 °C, NaCl, PEG, methyl viologen (MV) and hydrogen peroxide (H2O2), but not by 30 °C and 35 °C. Meanwhile, LeCDJ1 was involved in the response of plants to abscisic acid (ABA). Under heat stress, the sense plants showed better growth, higher chlorophyll content, lower malondialdehyde (MDA) accumulation and relative electrical conductivity (REC), and also less PSII photoinhibition than WT. Interestingly, the sense plants treated with streptomycin (SM), an inhibitor of organellar translation, still showed higher maximum photochemistry efficiency of PSII (Fv/Fm) and D1 protein levels than the SM‐untreated WT, suggesting that the protective effect of LeCDJ1 on PSII was, at least partially, independent of D1 protein synthesis. Furthermore, the relatively lower superoxide radical (O2•−) and H2O2 levels in the sense plants were considered to be due to the higher ascorbate peroxidase (APX) and superoxide dismutase (SOD) activity, which seemed unlikely dependent on their transcription level. These results indicated that LeCDJ1 overexpression facilitated heat tolerance in transgenic tomatoes.
Enteric neuroplasticity in seawater‐adapted European eel (Anguilla anguilla)
Authors: Sorteni C. , Clavenzani P. , De Giorgio R. , Portnoy O. , Sirri R. , Mordenti O. , Di Biase A. , Parmeggiani A. , Menconi V. , Chiocchetti R.
Published: October 2013

European eels live most of their lives in freshwater until spawning migration to the Sargasso Sea. During seawater adaptation, eels modify their physiology, and their digestive system adapts to the new environment, drinking salt water to compensate for the continuous water loss. In that period, eels stop feeding until spawning. Thus, the eel represents a unique model to understand the adaptive changes of the enteric nervous system (ENS) to modified salinity and starvation. To this purpose, we assessed and compared the enteric neuronal density in the cranial portion of the intestine of freshwater eels (control), lagoon eels captured in brackish water before their migration to the Sargasso Sea (T0), and starved seawater eels hormonally induced to sexual maturity (T18; 18 weeks of starvation and treatment with standardized carp pituitary extract). Furthermore, we analyzed the modification of intestinal neuronal density of hormonally untreated eels during prolonged starvation (10 weeks) in seawater and freshwater. The density of myenteric (MP) and submucosal plexus (SMP) HuC/D‐immunoreactive (Hu‐IR) neurons was assessed in wholemount preparations and cryosections. The number of MP and SMP HuC/D‐IR neurons progressively increased from the freshwater to the salty water habitat (control > T0 > T18; P < 0.05). Compared with freshwater eels, the number of MP and SMP HuC/D‐IR neurons significantly increased (P < 0.05) in the intestine of starved untreated salt water eels. In conclusion, high salinity evokes enteric neuroplasticity as indicated by the increasing number of HuC/D‐IR MP and SMP neurons, a mechanism likely contributing to maintaining the body homeostasis of this fish in extreme conditions.
Flaccid Penile Acceleration as a Marker of Cardiovascular Risk in Men without Classical Risk Factors
Authors: Rastrelli Giulia , Corona Giovanni , Lotti Francesco , Aversa Antonio , Bartolini Marco , Mancini Mario , Mannucci Edoardo , Maggi Mario
Published: October 2013

Introduction

Conventional cardiovascular (CV) risk factors identify only half of subjects with incident major adverse CV events (MACE). Hence new markers are needed in high CV risk subjects, as those with erectile dysfunction (ED). A role for dynamic peak systolic velocity (D-PSV) at penile color Doppler ultrasound (PCDU) has been suggested, but it is operator dependent and time consuming. Flaccid penile acceleration (FPA) is a PCDU parameter that reflects PSV, the systolic rise time (SRT), and end diastolic velocity (EDV), arithmetically defined as (PSV−EDV)/SRT.

Aim

The study aims to verify, in a large series of ED patients, whether FPA has a role in predicting MACE.

Methods

A selected series of 1,903 patients (aged 54.6 ± 11.7) with a suspected organic component for ED was retrospectively studied from January 2000 until July 2012. A subset of this sample (n = 622) was enrolled in a longitudinal study that ended in December 2007.

Main Outcome Measures

Several clinical, biochemical, and instrumental (PCDU) parameters were studied.

Results

Decreased FPA levels were associated with worse metabolic profile and sexual symptoms. In addition, FPA was positively associated with both total and calculated free testosterone. In the longitudinal study, unadjusted incidence of MACE was significantly associated with lower baseline FPA. When FPA was introduced in a multivariate model, along with D-PSV, after adjusting for age and Chronic Disease Score, lower FPA, but not D-PSV, was associated with incident MACE in lower-risk—i.e., younger (HR = 0.48 [0.23–0.99]), nonhypertensive (HR = 0.59 [0.38–0.92]), nonobese (HR = 0.68 [0.49–0.96]), or nondiabetic (HR = 0.67 [0.49–0.96] subjects; all P < 0.05—but not in higher-risk ones. FPA demonstrated a threshold effect in predicting MACE at a value <1.17 m/s2 which showed a threefold increase in incidence of MACE in apparently lower-risk individuals.

Conclusions

FPA is an easily obtained PCDU parameter and capable of identifying adverse metabolic and CV profiles, particularly in apparently lower-risk individuals with ED.
Assessment of coyote–wolf–dog admixture using ancestry‐informative diagnostic SNPs
Authors: Monzón J. , Kays R. , Dykhuizen D. E.
Published: October 2013

The evolutionary importance of hybridization as a source of new adaptive genetic variation is rapidly gaining recognition. Hybridization between coyotes and wolves may have introduced adaptive alleles into the coyote gene pool that facilitated an expansion in their geographic range and dietary niche. Furthermore, hybridization between coyotes and domestic dogs may facilitate adaptation to human‐dominated environments. We genotyped 63 ancestry‐informative single‐nucleotide polymorphisms in 427 canids to examine the prevalence, spatial distribution and the ecology of admixture in eastern coyotes. Using multivariate methods and Bayesian clustering analyses, we estimated the relative contributions of western coyotes, western and eastern wolves, and domestic dogs to the admixed ancestry of Ohio and eastern coyotes. We found that eastern coyotes form an extensive hybrid swarm, with all our samples having varying levels of admixture. Ohio coyotes, previously thought to be free of admixture, are also highly admixed with wolves and dogs. Coyotes in areas of high deer density are genetically more wolf‐like, suggesting that natural selection for wolf‐like traits may result in local adaptation at a fine geographic scale. Our results, in light of other previously published studies of admixture in Canis, revealed a pattern of sex‐biased hybridization, presumably generated by male wolves and dogs mating with female coyotes. This study is the most comprehensive genetic survey of admixture in eastern coyotes and demonstrates that the frequency and scope of hybridization can be quantified with relatively few ancestry‐informative markers.
Diffuse symbioses: roles of plant–plant, plant–microbe and microbe–microbe interactions in structuring the soil microbiome
Authors: Bakker Matthew G. , Schlatter Daniel C. , Otto‐Hanson Lindsey , Kinkel Linda L.
Published: October 2013

A conceptual model emphasizing direct host–microbe interactions has dominated work on host‐associated microbiomes. To understand plant–microbiome associations, however, broader influences on microbiome composition and functioning must be incorporated, such as those arising from plant–plant and microbe–microbe interactions. We sampled soil microbiomes associated with target plant species (Andropogon gerardii, Schizachyrium scoparium, Lespedeza capitata, Lupinus perennis) grown in communities varying in plant richness (1‐, 4‐, 8‐ or 16‐species). We assessed Streptomyces antagonistic activity and analysed bacterial and Streptomyces populations via 454 pyrosequencing. Host plant species and plant richness treatments altered networks of coassociation among bacterial taxa, suggesting the potential for host plant effects on the soil microbiome to include changes in microbial interaction dynamics and, consequently, co‐evolution. Taxa that were coassociated in the rhizosphere of a given host plant species often showed consistent correlations between operational taxonomic unit (OTU) relative abundance and Streptomyces antagonistic activity, in the rhizosphere of that host. However, in the rhizosphere of a different host plant species, the same OTUs showed no consistency, or a different pattern of responsiveness to such biotic habitat characteristics. The diversity and richness of bacterial and Streptomyces communities exhibited distinct relationships with biotic and abiotic soil characteristics. The rhizosphere soil microbiome is influenced by a complex and nested array of factors at varying spatial scales, including plant community, plant host, soil edaphics and microbial taxon and community characteristics.
Combination of caspofungin and low‐dose trimethoprim/sulfamethoxazole for the treatment of severe Pneumocystis jirovecii pneumonia in renal transplant recipients
Authors: Tu Guo‐wei , Ju Min‐jie , Xu Ming , Rong Rui‐ming , He Yi‐zhou , Xue Zhang‐gang , Zhu Tong‐yu , Luo Zhe
Published: October 2013

Pneumocystis jirovecii pneumonia (PJP) is a severe and life‐threatening complication in immunocompromised patients. Trimethoprim/sulfamethoxazole (TMP‐SMZ) is well known for its effectiveness as prophylaxis of PJP. However, the use of TMP‐SMZ is associated with various adverse effects that may not be tolerated by critically ill patients. Caspofungin is recommended for invasive fungal infections, but the treatment of PJP after solid organ transplantation (SOT) is an off‐label use of this drug. In this study, three cases of severe PJP in renal transplant recipients treated with a combination of caspofungin and low‐dose TMP‐SMZ were presented. Initial findings indicated that the combined treatment may be beneficial for the treatment of PJP and decrease the incidence of TMP‐SMZ‐related adverse effects.
Editorial: Jim Blaut and the trajectories of tropical geography
Authors: Bunnell Tim , Ong Chin Ee , Sidaway James D.
Published: October 2013

High resolution scan of Blaut JM (1953) Malayan Journal of Tropical Geography
Knowledge, Attitudes and Practices of Primary Care Physicians in the Franche‐Comte Region (France) Regarding the Risk of Rabies
Authors: Jeanpetit R. , Bellanger A.‐P. , Piotte E. , Haffner‐Mauvais C. , Marguet P.
Published: October 2013

Rabies remains a public health concern and is associated with a mortality rate of nearly 100%. An observational survey was undertaken in 2010 to assess the knowledge, attitudes and practices of primary care physicians (PCPs) in our area regarding the risk of rabies. Standardized questionnaires were sent to a random sample of 400 PCPs practicing in the Franche‐Comté region (eastern France), requesting their voluntary and anonymous participation. The questionnaires requested socio‐demographic details and self‐evaluation. Seven clinical situations were selected to assess the attitudes of physicians. The response rate was 38.5%. Most of the PCPs were based in rural and semi‐rural areas, 76% knew where their nearest rabies centre was located and 75% of them claimed their knowledge of the risk of rabies was poor. While most of them (>80%) knew which animals transmitted the disease as well as the severity criteria for bites, only 12% knew that there was no contraindication for the rabies vaccine in the event of exposure to the disease. Responses to the seven clinical situations showed that most of them did not know the precise indication for the rabies vaccine and rabies immunoglobulin. Primary care physicians are usually aware of the risk of rabies, but their knowledge of how to manage rabies exposure and prevention often requires updating. The health authorities should provide more detailed information to PCPs and to the general population about the risk of rabies.
Home advantage and sports performance: evidence, causes and psychological implications
Authors: Legaz Arrese Alejandro , Moliner Urdiales Diego , Munguía Izquierdo Diego
Published: October 2013

Home advantage in competitive sports is well documented despite some contradictory results. Previous studies have identified 5 main causes of home advantage in competitive sports: crowd, familiarity, travels, rules and territoriality. Moreover, several studies have proposed the influence of these factors over psychological and behavioral states in athletes, coaches and referees. The present review summarizes the available scientific evidences about home advantage in sport and tries to identify the environmental and psychological causes of this phenomenon.
Numerical computation for teaching quantum statistics
Authors: Price Tyson , Swendsen Robert H.
Published: October 2013

The study of ideal quantum gases reveals surprising quantum effects that can be observed in macroscopic systems. The properties of bosons are particularly unusual because a macroscopic number of particles can occupy a single quantum state. We describe a computational approach that supplements the usual analytic derivations applicable in the thermodynamic limit. The approach involves directly summing over the quantum states for finite systems and avoids the need for doing difficult integrals. The results display the unusual behavior of quantum gases even for relatively small systems.
Generalization of the imitation effect within a natural class
Authors: Nielsen Kuniko
Published: October 2013

A natural class refers to a set of segments which share acoustic or articulatory features. Support for this notion has traditionally been provided by phonological alternations and phonotactic constraints, and recently by experiments (e.g., Goldrick, 2004). This study investigates the psychological reality of natural class using the imitation paradigm (Goldinger, 1998) in which subjects speech is compared before and after they are exposed to target speech (= study phase). Although this paradigm has shown that subjects shift their production in the direction of the target, these results do not reveal the size of the linguistic unit(s) influenced by the effect. That is, when a subject shifts production of a particular sound in a word, it is uncertain whether the subject is picking up on the word, the segment, or the feature. In this study, to investigate whether phonetic imitation is generalized across members of a natural class, the study-phase word list includes words with initial /p/ and /t/ (with extended VOT), while the pre- and post-study production list includes (1) the modeled words, replicating Shockley et al. (2004), (2) the modeled segments /p/ and /t/ in new words, and (3) the modeled feature [+spread glottis] (aspiration) in a new segment /k/.
Quality of American English back vowels before /r/.
Authors: Clark Michael J. , Hillenbrand James M.
Published: October 2013

The vowels /o/ and /■/ are not contrastive before /r/ in most American English dialects, and the phonetics literature is equivocal about the phonetic quality of the nucleus in words such as board. Most works use [■] to represent the first part of the nucleus. In this study acoustic measurements, listening tests, and discriminant analyses were used to determine the phonetic quality of such vowels. Fourteen women recorded monosyllables containing /o,■,■/, with initial /b,g,h/ and final /d/ or /z/ (e.g., bode, Baud, bod). Additionally a set with rhotic diphthongs (board, barred, gored, guard, hoard, hard) was recorded. The central back vowel in rhotic diphthong syllables (board, gored, hoard) showed formant values very similar to those for /o/ and very unlike those for /■/. The low back rhotic diphthong (i.e., barred, guard, hard) showed a range of values from /■/ to /■/. Listening tests using brief excerpts from vowel onsets supported the greater similarity of board to bode than to Baud and the intermediate nature of barred between bod and Baud. Discriminant classification of the rhotic diphthong formant measures supported the same conclusions. [Work supported by NIH.]
Decomposition method in constructing simulation models of parametric location for statistically irregular mediums
Authors: Starchenko Irene
Published: October 2013

In using parametric arrays for the purposes of distant sounding in a water medium it is necessary to take into account the probable characteristics of acoustic signals. In this case the modeling of processes is especially important, because experiments in natural conditions are not always possible. In the case of parametric location the medium plays the very important function of formation of the parametric array. Results will be discussed.
Characterization and prediction of low frequency sound in workrooms
Authors: Wong Galen , Hodgson Murray
Published: October 2013

Low-frequency noise is of concern in industrial settings since workers are subjected to long-term exposures of low-frequency noise caused by machinery which can adversely affect human health and well-being. Passive noise-control methods are usually not cost-effective. Active noise control, on the other hand, is most effective at low frequencies. As part of a project investigating active noise control of low-frequency noise in these settings, and how to predict its benefit, measurements were performed on the propagation of low-frequency noise in a workroom, with and without fittings the obstacles in the room to understand their effects and importance in prediction models. Measurements performed in a real-world workroom, as well as in a scale model workroom show that fittings alter the sound field in an unpredictable manner. With low-frequency octave band filtered noise output, changes in the sound pressure level of 10 dB or more were measured in both cases. Prediction of low-frequency noise in workrooms was performed using an image-phase and a modal model—which do not account for the effects of fittings. Predictions were compared to measurements in full-scale and scale-model workrooms with pure tone outputs. So far it has proven difficult to accurately model low-frequency effects in large workrooms.
Analysis of diffuse broadband sound fields in enclosures by decomposition in powers of an absorption parameter
Authors: Bliss Donald B. , Rouse Jerry W. , Franzoni Linda P.
Published: October 2013

A novel analysis for steady-state or time-dependent broadband diffuse sound fields in enclosures is developed. Beginning with a formulation utilizing broadband intensity boundary sources, the strength of these wall sources is expanded in a series in powers of an absorption parameter, thereby giving a separate boundary integral problem for each power. The first problem has a uniform interior field level proportional to the reciprocal of the absorption parameter, as expected. The second problem gives a mean-square pressure distribution that is independent of the absorption parameter and is primarily responsible for the spatial variation of the reverberant field. This problem depends on the location of sources and the spatial distribution of absorption, but not absorption level. Additional problems proceed at integer powers of the absorption parameter, but are essentially higher order corrections to the spatial variation. The important second problem and the higher order problems are easily solved numerically, but closed form approximate solutions based on one iteration step are simple and accurate. Solutions obtained by retaining only the first couple of terms in the series expansion are compared to complete solutions obtained by another approach, and good agreement is shown between the two methods.
Vector-Doppler ultrasound for the detection of internal bleeding
Authors: Cunitz Bryan W. , Kaczkowski Peter J. , Brayman Andrew A.
Published: October 2013

A vector Doppler (VDop) ultrasound system uses a transmitter and a spatially separated pair of receivers to measure bistatic scattering from blood. VDop has two principal advantages over color-flow Doppler in identifying internal bleeding: (1) measures flow direction, and thus absolute magnitude of flow velocity (2) does not require special orientation to detect and measure flow, thus can measure flows perpendicular to the transmitter. Our hypothesis is that real-time flow direction and magnitude can be used to detect and characterize internal bleeding. A real-time vector Doppler system has been built and tested in vitro. The system is capable of measuring flow magnitude and direction up to 145 cm/s at a depth of 3.6 cm at a processing rate of 10 Hz. Accuracy was measured using a calibrated moving string phantom and the system performs well within a useful range. A blood flow phantom was developed to mimic arterial flow into an open cavity as well as into tissue and replicate both pulsatile flow as well as the energy storage due to vascular elasticity. Flow signature data is gathered under conditions of normal branching flow, and vessel breach. The talk will describe the VDop system and the flow phantom and summarize results.
Microscopic dynamic magnetic resonance elastography
Authors: Othman Shadi F. , Royston Thomas J. , Magin Richard L.
Published: October 2013

Microscopic magnetic resonance elastography (uMRE) is a high resolution imaging technique for measuring the viscoelastic properties of small synthetic and biological samples. Mechanical shear waves, typically with amplitudes of less than 100 μm and frequencies of 500–600 Hz, are induced using a piezoelectric oscillator directly coupled to the region of interest. By using multiple phase offsets and motion encoding gradients we acquire data that allows the generation of images that depict shear wave motion and the calculation of local values of the tissue viscoelastic properties. Recent MRE investigations are increasingly being conducted at higher spatial resolution to establish histological correlations between elasticity maps and tissue structures; such microscopic MRE studies require stronger static fields, stronger magnetic field gradients, higher performance RF coils, and more compact, higher frequency mechanical actuators. Microscopic MRE experiments were conducted at 11.74 T in a 54 mm diameter vertical bore magnet with a 10 mm diameter×25 mm length cylindrical space available for imaging. The field-of-view ranged from 4 to 14 mm. The study was conducted on agarose gel phantoms of different concentrations ranging from 025%–1% w. Different biological samples, including frog oocytes and tissue engineered constructs, were also tested.
Acoustical considerations in the design—and re-design—of the violin
Authors: Curtin Joseph
Published: October 2013

The violin is a highly evolved instrument which has long resisted significant changes to its design and construction. Still, acoustical research over the past several decades has shed sufficient light on the workings of the violin that makers can now consider non-traditional approaches to their craft in order to optimize the sound, playability, and consistency of their instruments. The work of researchers such as Duennwald, Haines, Hutchins, and Weinreich will be considered in terms of its usefulness as a guide to building better violins.
Classical guitar construction: The acoustician’s tale
Authors: Richardson Bernard E.
Published: October 2013

The vast majority of guitars produced today are built according to general principles laid down in the nineteenth century. Nevertheless, the devil is in the detail, and innovative makers constantly reappraise the design and construction of instruments in their endeavors to control quality or to seek ‘‘improvement.’’ The maker’s approach, necessarily, tends to be pragmatic, but it is one which can be greatly informed by the application of relatively simple acoustical models. This paper will examine various important design aspects—for example choice of materials, body size, strutting, soundboard thickness—introducing the basis for making informed decisions.
Long-range excitation of vibrational response in landmines with Rayleigh and Love waves
Authors: Muir Thomas
Published: October 2013

An experiment was conducted in a clay soil at a range of 25 m from two types of electromagnetic shaker sources, operating in a cw pulse mode centered at 100 Hz. The sources were in co-located arrays, one vertically oriented to generate Rayleigh waves and another transversely oriented to generate Love waves. Two cylindrical landmine targets were used: an unloaded (empty) plastic shell, and a metal shell, loaded with paraffin to simulate an explosive. These target types represent extreme variations in what could conceivably be encountered. The targets were instrumented with three-axis seismometers and accelerometers, and were also viewed with a laser Doppler vibrometer (LDV). Data were acquired on both mine cases in various stages of deployment, including sitting upon the ground surface, snugged in to a tight hole in the ground, and completely buried some 5 cm beneath the surface. The responses of the mine cases to Rayleigh and Love wave excitation were measured and compared to data from a reference seismometer deployed nearby, on natural, undisturbed soil. The mine case responses to these seismic excitation fields, under a number of conditions are presented and discussed. [Work supported by the U.S. Marine Corps Systems Command.]
Measurements of the rate of change of the power spectral density due to nonlinearity in one-dimensional propagation
Authors: Falco Lauren E. , Gee Kent L. , Atchley Anthony A.
Published: October 2013

The influence of nonlinear effects in the propagation of jet noise is typically characterized by examining the change in the power spectral density (PSD) of the noise as a function of propagation distance. The rate of change of the PSD is an indicator of the importance of nonlinearity. Morfey and Howell [AIAA J. 19, 986–992 (1981)] introduced an analysis technique that has the potential to extract this information from a measurement at a single location. They develop an ensemble-averaged Burgers equation that relates the rate of change of the PSD with distance to the quantity Qp2p, which is the imaginary part of the cross-spectral density of the pressure and the square of the pressure. Despite its potential applicability to jet noise analysis, the physical significance and utility of Qp2p have not been thoroughly studied. This work examines Qp2p for the one-dimensional propagation of plane waves in a shock tube. The use of such a simple, controlled environment allows for a better understanding of the significance of Qp2p. [Work supported by the National Science Foundation, the Office of Naval Research, and the Strategic Environmental Research and Development Program.]
The difference in auditory memory between young and aged listeners with normal hearing
Authors: Schneider Bruce , Qi James , Huang Juan , Wu Xihong , Li Liang
Published: October 2013

The perceptual fusion of a noise with its delayed copies implies that there is a memory for maintaining a detailed representation of an arbitrary waveform. This auditory memory would be important for perceptually grouping correlated sounds and segregating uncorrelated sounds in noisy, reverberant environments, in which older listeners find it much more difficult than younger listeners to process signals. To determine the temporal extent of the auditory memory and whether it is affected by aging, this study investigated the detection of a break in correlation between two correlated broadband noises in younger and older listeners with normal hearing. The results show that younger listeners could detect a 100-ms break in correlation up to interaural delays ranging from 6.3 to 23.0 ms, suggesting that higher-order central mechanisms beyond the brainstem delay lines are likely to be involved in maintaining a memory trace of the fine details of the acoustic waveform. Aged listeners, however, could detect the break up to interaural delays ranging only from 6.7 to 9.7 ms, indicating the age-related decline in auditory memory. This decline may be one of the main causes leading to perceptual difficulties experienced by older listeners in noisy, reverberant environments. [Work supported by NSERCC and MSTC.]
Time reversal in heterogeneous flexural beams
Authors: Francoeur Dany , Berry Alain
Published: October 2013

Time reversal of acoustic and structure-borne waves has been explored in recent years mostly for ultrasound and for nondispersive propagation, that is under frequency-independent wave velocity. In contrast, the case of time reversal in flexural beams presented here involves dispersive propagation, and is carried for frequencies below 5 kHz. The study has been started with analytical time reversal simulations in infinite homogeneous or heterogeneous beams (comprising point-mass scatterers). Experiments have also been realized on a 5 m beam with anechoic terminations and under transverse impact excitation. The time-reversal mirror was made of several thin piezoceramic elements bonded on the beam to sense the impulse response of the structure and re-emit its time-reversed image. The experimental results are in good agreement with the analytical results, and show that time spreading due to dispersive propagation of bending waves is successfully compensated by the time reversal operation. The presentation will illustrate the main results of the simulations and a comparison with the experiments.
Vibration control of optomechanical components
Authors: Ryaboy Vyacheslav M.
Published: October 2013

The purpose of optomechanical components is to anchor optical elements (such as light sources, lenses, mirrors, etc.) in space so that the optical paths would be unperturbed by environmental impacts, first of all by vibration. Dynamic alignment of components is a main design optimization criterion for the optomechanical systems. An optical table or breadboard is often used as a common base for the whole optomechanical assembly. It can be sufficiently isolated from the floor vibration, but its own flexural resonance vibrations may still cause misalignments. The paper estimates various ways of vibration damping of optical tables, including new methods of passive damping combined with motion transformation, as well as active damping. Optical rods and posts offset optical elements from the table. These components have their own resonance properties. The paper presents analytical estimates and optimization methods for introducing damping materials in the optical posts. Experimental results comparing dynamic properties of damped and non-damped structures will be presented.
Simulation of temporal aspects of auditory aging
Authors: MacDonald Ewen , Pichora-Fuller Kathy , Schneider Bruce
Published: October 2013

A jittering technique to disrupt the periodicity of the signal was used to simulate the effect of the loss of temporal synchrony coding believed to characterize auditory aging. In one experiment jittering was used to distort the frequency components below 1.2 kHz and in a second experiment the components above 1.2 kHz were distorted. To control for spectral distortion introduced by jittering, comparison conditions were created using a smearing technique (Baer and Moore, 1993). In both experiments, 16 normal hearing young adult subjects were presented with SPIN sentences in three conditions (intact, jittered, and smeared) at 0 and 8 dB SNR. When the low frequencies were distorted, speech intelligibility in the jittered conditions was significantly worse than in the intact and smeared conditions, but the smeared and intact conditions were equivalent. When the high frequencies were distorted, speech intelligibility was reduced similarly by jittering and smearing. On low-context jittered sentences, results for young adults mimicked results found previously for older listeners with good audiograms (Pichora-Fuller et al., 1995). It is argued that the jittering technique could be used to simulate the loss of neural synchrony associated with age-related changes in temporal auditory processing.
Predicting speech intelligibility in real-world noise environments from functional measures of hearing
Authors: Giguère Christian , Laroche Chantal , Vaillancourt Véronique , Soli Sigfrid
Published: October 2013

In everyday life situations and in many occupational settings, speech communication is often performed in noisy environments. These environments can sometimes be very challenging, particularly for individuals impaired by hearing loss. Diagnostic measures of hearing, such as the audiogram, are not adequate to make accurate predictions of speech intelligibility in real-world noise environments. Instead, a direct functional measure of hearing, the Hearing In Noise Test (HINT), has been identified and validated for use in predicting speech intelligibility in a wide range of face-to-face speech communication situations in real-world noise environments. The prediction approach takes into account the voice level of the talker in noise due to the Lombard effect, the communication distance between the talker and the listener, a statistical model of speech perception in specific noises, and the functional hearing abilities of the listener. The latter is taken as the elevation of the individual’s speech reception threshold in noise above the normative value for the HINT test. This test is available in several languages, so that language-specific needs can be addressed. The detailed approach will be presented with an emphasis placed on application examples in clinical and/or occupational settings.
Autonomous acoustic sensing on mobile ground and aerial platforms
Authors: Pham Tien , Srour Nassy
Published: October 2013

Acoustic sensor systems on the ground and/or in the air can be used effectively for autonomous and remote intelligence surveillance and reconnaissance (ISR) applications. Acoustic sensors can be used as primary sensors and/or secondary sensors to cue other higher-resolution sensors for detection, tracking and classification of continuous and transient battlefield acoustic events such as ground vehicles, airborne aircraft, personnel, indirect fire, and direct fire. Current collaborative research activities at ARL in acoustic sensing from mobile ground platforms such as HMMWVs and small robotic vehicles [P. Martin and S. Young, Proc. of SPIE Defense & Security Symposium, 2004] and from aerial platforms such as UAVs and balloons [Reiff, Pham et al, Proc. of the 24th Army Science Conference, 2004] demonstrate practical performance enhancements over fixed ground-based platforms for a number of ISR applications. For both mobile ground and aerial platforms, self-generated noise (flow noise and platform noise) is problematic but they can be suppressed with specialized windscreens, sensor placement, and noise cancellation technology. Typical acoustic detection and processing results for mobile platforms are compared and contrasted against fixed ground-based platforms.