A system for room acoustic simulation for one's own voice

The real-time simulation of room acoustical environments for one’s own voice, using generic software, has been difficult until very recently due to the computational load involved: requiring real-time convolution of a person’s voice with a potentially large number of long room impulse responses. This thesis is presenting a room acoustical simulation system with a software-based solution to perform real-time convolutions with headtracking; to simulate the effect of room acoustical environments on the sound of one’s own voice, using binaural technology. In order to gather data to implement headtracking in the system, human head- movements are characterized while reading a text aloud. The rooms that are simulated with the system are actual rooms that are characterized by measuring the room impulse response from the mouth to ears of the same head (oral binaural room impulse response, OBRIR). By repeating this process at 2o increments in the yaw angle on the horizontal plane, the rooms are binaurally scanned around a given position to obtain a collection of OBRIRs, which is then used by the software-based convolution system. In the rooms that are simulated with the system, a person equipped with a near- mouth microphone and near-ear loudspeakers can speak or sing, and hear their voice as it would sound in the measured rooms, while physically being in an anechoic room. By continually updating the person’s head orientation using headtracking, the corresponding OBRIR is chosen for convolution with their voice. The system described in this thesis achieves the low latency that is required to simulate nearby reflections, and it can perform convolution with long room impulse responses. The perceptual validity of the system is studied with two experiments, involving human participants reading aloud a set-text. The system presented in this thesis can be used to design experiments that study the various aspects of the auditory perception of the sound of one’s own voice in room environments. The system can also be adapted to incorporate a module that enables listening to the sound of one’s own voice in commercial applications such as architectural acoustic room simulation software, teleconferencing systems, virtual reality and gaming applications, etc

The Metamorphosis of Tidally Stirred Dwarf Galaxies

We present results from high-resolution N-Body/SPH simulations of rotationally supported dwarf irregular galaxies moving on bound orbits in the massive dark matter halo of the Milky Way.The dwarf models span a range in disk surface density and the masses and sizes of their dark halos are consistent with the predictions of cold dark matter cosmogonies. We show that the strong tidal field of the Milky Way determines severe mass loss in their halos and disks and induces bar and bending instabilities that transform low surface brightness dwarfs (LSBs) into dwarf spheroidals (dSphs) and high surface brightness dwarfs (HSBs) into dwarf ellipticals (dEs) in less than 10 Gyr. The final central velocity dispersions of the remnants are in the range 8-30 km/s and their final $v/\sigma$ falls to values $< 0.5$, matching well the kinematics of early-type dwarfs. The transformation requires the orbital time of the dwarf to be \simlt 3-4 Gyr, which implies a halo as massive and extended as predicted by hierarchical models of galaxy formation to explain the origin of even the farthest dSph satellites of the Milky Way, Leo I and Leo II. Only dwarfs with central dark matter densities as high as those of Draco and Ursa Minor can survive for 10 Gyr in the proximity of the Milky Way: this is naturally achieved within hierarchical models, where the densest objects should have small orbital times due to their early formation epochs. Part of the gas is stripped and part is funneled to the center due to the bar, generating one strong burst of star formation in HSBs and smaller, multiple bursts in LSBs. Extended low-surface brightness stellar and gaseous streams originate from LSBs and, when projected along the line of sight, can lead to overestimate the mass-to-light ratio of the bound remnant by a factor \simlt 2,Comment: 29 pages, 34 figures, submitted to ApJ. Figures 5,11 and 32 are given as separate GIF files. Other figures and the movies of the simulations can be found at http://pcblu.mib.infn.it/~lucio/LG/LG.htm

THE KINEMATIC SIGNATURE OF FACE-ON PEANUT-SHAPED BULGES

We present a kinematic diagnostic for peanut-shaped bulges in nearly face-on galaxies. The face-on view provides a novel perspective on peanuts that would allow study of their relation to bars and disks in greater detail than hitherto possible. The diagnostic is based on the fact that peanut shapes are associated with a flat density distribution in the vertical direction. We show that the kinematic signature corresponding to such a distribution is a minimum in the fourth-order Gauss-Hermite moment s4. We demonstrate our method on N-body simulations of varying peanut strength, showing that strong peanuts can be recognized to inclinations i ’ 300, regardless of the strength of the bar. We also consider compound systems in which a bulge is present in the initial conditions, as may happen if bulges form at high redshift through mergers. We show that in this case, because the vertical structure of the bulge is not derived from that of the disk, the signature of a peanut in s4 is weakened. Thus the same kinematic signature of peanuts can be used to explore bulge formation mechanisms. The observational requirements for identifying peanuts with this method are challenging, but feasible

Teachers' ideas versus experts' descriptions of 'the good teacher' in postgraduate medical education: implications for implementation. A qualitative study

Contains fulltext : 96394.pdf (publisher's version ) (Open Access)BACKGROUND: When innovations are introduced in medical education, teachers often have to adapt to a new concept of what being a good teacher includes. These new concepts do not necessarily match medical teachers' own, often strong beliefs about what it means to be a good teacher.Recently, a new competency-based description of the good teacher was developed and introduced in all the Departments of Postgraduate Medical Education for Family Physicians in the Netherlands. We compared the views reflected in the new description with the views of teachers who were required to adopt the new framework. METHODS: Qualitative study. We interviewed teachers in two Departments of Postgraduate Medical Education for Family Physicians in the Netherlands. The transcripts of the interviews were analysed independently by two researchers, who coded and categorised relevant fragments until consensus was reached on six themes. We investigated to what extent these themes matched the new description. RESULTS: Comparing the teachers' views with the concepts described in the new competency-based framework is like looking into two mirrors that reflect clearly dissimilar images. At least two of the themes we found are important in relation to the implementation of new educational methods: the teachers' identification and organisational culture. The latter plays an important role in the development of teachers' ideas about good teaching. CONCLUSIONS: The main finding of this study is the key role played by the teachers' feelings regarding their professional identity and by the local teaching culture in shaping teachers' views and expectations regarding their work. This suggests that in implementing a new teaching framework and in faculty development programmes, careful attention should be paid to teachers' existing identification model and the culture that fostered it

Coughing in pre-school children in general practice: When are RAST's for inhalation allergy indicated?

To identify patterns of clinical history associated with extreme (high or low) probabilities of allergic sensitization in coughing children so as to restrict allergy testing to those with an intermediate probability of sensitization. A total of 752 children, aged 1-4, visiting their GPs for coughing (greater than or equal to5 days), were tested for IgE-antibodies to house dust mite, cat and dog [RadioAllergoSorbent Test (RAST)]. Parents completed a questionnaire on family history of atopy, breastfeeding, smoking, pets, and floor covering. Data of 640 children could be analyzed, 83 (13%) were IgE-positive. In a logistic regression analysis, a scoring formula for the prediction of being IgE-positive was constructed using variables from the patient's history. Significant contributors for sensitization were: age (3-4 yr), infantile eczema, positive family history of mite-allergy, sibling(s) with pollen-allergy, and smoking by parents. If only one of these characteristics is present, the probability of sensitization is <25%. In such cases watchful waiting may be preferred over allergy testing. In other cases, a negative RAST may help to exclude sensitization, whereas a positive RAST helps to establish the diagnosis. Thus, acting on clinical history alone may save approximately 80% of RAST's. Patient history-derived information contributes to distinguishing children who are at low risk for sensitization to house dust mite, cat, and dog. The scoring formula may help GPs to identify children with a low probability of being sensitized. This may form the basis for watchful waiting. In others, allergy testing may be useful to gain more diagnostic certaint

GPs' assessment of patients' readiness to change diet, activity and smoking

BACKGROUND: The Stages of Change Model is increasingly used for lifestyle counselling. In general practice, the use of algorithms to measure stage of change is limited, but for successful counselling it is important to know patients' readiness to change. AIM: To assess the accuracy of the assessment of patients' readiness to change fat consumption, physical activity, and smoking by GPs and general practice registrars. DESIGN OF STUDY: Cross-sectional questionnaire-based survey. SETTING: One hundred and ninety-nine patients at elevated cardiovascular risk aged 40–70 years, 24 GPs, and 21 registrars in Dutch general practices. METHOD: Patients were asked to complete an algorithm to measure their motivation to change fat consumption, physical activity, and smoking. GPs and registrars were given descriptions of the stages of change for the three lifestyles, and were asked to indicate the description that matched their patient. Cohen's κ was calculated as measure of agreement between patients and GPs/registrars. RESULTS: Registrars' patients were younger, and less often overweight and hypertensive than GPs' patients. Cohen's κ for smoking was moderate (0.50, 95% confidence interval [CI] = 0.34 to 0.67 for GPs and 0.47, CI = 0.27 to 0.68 for registrars). Agreement for fat and activity was poor to fair. No differences in accuracy were observed between GPs and registrars (P = 0.07–0.83). CONCLUSIONS: Low accuracy indicates that counselling in general practice is often targeted at the wrong people at the wrong time. Improvements can possibly be achieved by making registration of lifestyle parameters in patient records common practice, and by simply asking patients where they stand in respect to lifestyle change

Are family practice trainers and their host practices any better? comparing practice trainers and non-trainers and their practices

Contains fulltext : 117900.pdf (publisher's version ) (Open Access)BACKGROUND: Family Physician (FP) trainees are expected to be provided with high quality training in well organized practice settings. This study examines differences between FP trainers and non-trainers and their practices to see whether there are differences in trainers and non-trainers and in how their practices are organized and their services are delivered. METHOD: 203 practices (88 non-training and 115 training) with 512 FPs (335 non-trainers and 177 trainers) were assessed using the "Visit Instrument Practice organization (VIP)" on 369 items (142 FP-level; 227 Practice level). Analyses (ANOVA, ANCOVA) were conducted for each level by calculating differences between FP trainees and non-trainees and their host practices. RESULTS: Trainers scored higher on all but one of the items, and significantly higher on 47 items, of which 13 remained significant after correcting for covariates. Training practices scored higher on all items and significantly higher on 61 items, of which 23 remained significant after correcting for covariates. Trainers (and training practices) provided more diagnostic and therapeutic services, made better use of team skills and scored higher on practice organization, chronic care services and quality management than non-training practices. Trainers reported more job satisfaction and commitment and less job stress than non-trainers. DISCUSSION: There are positive differences between FP trainers and non-trainers in both the level and the quality of services provided by their host practices. Training institutions can use this information to promote the advantages of becoming a FP trainer and training practice as well as to improve the quality of training settings for FPs

Effect of an integrated primary care model on the management of middle-aged and old patients with obstructive lung diseases

Contains fulltext : 51881.pdf (publisher's version ) (Open Access)OBJECTIVE: To investigate the effect of a primary care model for COPD on process of care and patient outcome. DESIGN: Controlled study with delayed intervention in control group. SETTING: The GP delegates tasks to a COPD support service (CSS) and a practice nurse. The CSS offers logistic support to the practice through a patient register and recall system for annual history-taking and lung function measurement. It also forms the link with the chest physician for diagnostic and therapeutic advice. The practice nurse's most important tasks are education and counselling. SUBJECTS: A total of 44 practices (n =22 for intervention and n =22 for control group) and 260 of their patients > or = 40 years with obstructive lung diseases. RESULTS: Within the intervention group planned visits increased from 16% to 44% and from 19% to 25% in the control condition (difference between groups p =0.014). Annual lung function measurement rose from 17% to 67% in the intervention and from 11% to 18% in the control group (difference between groups p =0.001). Compared with control, more but not statistically significant smokers received periodic advice to quit smoking (p =0.16). At baseline 41% of the intervention group were using their inhalers correctly and this increased to 54% after two years; it decreased in the control group from 47 to 29% (difference between groups p =0.002). The percentage of patients without exacerbation did not change significantly compared with the control condition. The percentage of the intervention group not needing emergency medication rose from 79% to 84% but decreased in the controls from 81 to 76% (difference between groups p =0.08). CONCLUSION: Combining different disciplines in one model has a positive effect on compliance with recommendations for monitoring patients, and improves the care process and some patient outcomes

Qualitative study about the ways teachers react to feedback from resident evaluations

Contains fulltext : 127324.pdf (publisher's version ) (Open Access)BACKGROUND: Currently, one of the main interventions that are widely expected to contribute to teachers' professional development is confronting teachers with feedback from resident evaluations of their teaching performance. Receiving feedback, however, is a double edged sword. Teachers see themselves confronted with information about themselves and are, at the same time, expected to be role models in the way they respond to feedback. Knowledge about the teachers' responses could be not only of benefit for their professional development, but also for supporting their role modeling. Therefore, research about professional development should include the way teachers respond to feedback. METHOD: We designed a qualitative study with semi-structured individual conversations about feedback reports, gained from resident evaluations. Two researchers carried out a systematic analysis using qualitative research software. The analysis focused on what happened in the conversations and structured the data in three main themes: conversation process, acceptance and coping strategies. RESULTS: The result section describes the conversation patterns and atmosphere. Teachers accepted their results calmly, stating that, although they recognised some points of interest, they could not meet with every standard. Most used coping strategies were explaining the results from their personal beliefs about good teaching and attributing poor results to external factors and good results to themselves. However, some teachers admitted that they had poor results because of the fact that they were not "sharp enough" in their resident group, implying that they did not do their best. CONCLUSIONS: Our study not only confirms that the effects of feedback depend first and foremost on the recipient but also enlightens the meaning and role of acceptance and being a role model. We think that the results justify the conclusion that teachers who are responsible for the day release programmes in the three departments tend to respond to the evaluation results just like human beings do and, at the time of the conversation, are initially not aware of the fact that they are role models in the way they respond to feedback