An analysis of the acoustic cavitation noise spectrum: The role of periodic shock waves

Research on applications of acoustic cavitation is often reported in terms of the features within the spectrum of the emissions gathered during cavitation occurrence. There is, however, limited understanding as to the contribution of specific bubble activity to spectral features, beyond a binary interpretation of stable versus inertial cavitation. In this work, laser-nucleation is used to initiate cavitation within a few millimeters of the tip of a needle hydrophone, calibrated for magnitude and phase from 125 kHz to 20 MHz. The bubble activity, acoustically driven at f0 = 692 kHz, is resolved with high-speed shadowgraphic imaging at 5 × 106 frames per second. A synthetic spectrum is constructed from component signals based on the hydrophone data, deconvolved within the calibration bandwidth, in the time domain. Cross correlation coefficients between the experimental and synthetic spectra of 0.97 for the f 0/2 and f 0/3 regimes indicate that periodic shock waves and scattered driving field predominantly account for all spectral features, including the sub-harmonics and their over-harmonics, and harmonics of f 0

Deterministic Partial Differential Equation Model for Dose Calculation in Electron Radiotherapy

Treatment with high energy ionizing radiation is one of the main methods in modern cancer therapy that is in clinical use. During the last decades, two main approaches to dose calculation were used, Monte Carlo simulations and semi-empirical models based on Fermi-Eyges theory. A third way to dose calculation has only recently attracted attention in the medical physics community. This approach is based on the deterministic kinetic equations of radiative transfer. Starting from these, we derive a macroscopic partial differential equation model for electron transport in tissue. This model involves an angular closure in the phase space. It is exact for the free-streaming and the isotropic regime. We solve it numerically by a newly developed HLLC scheme based on [BerCharDub], that exactly preserves key properties of the analytical solution on the discrete level. Several numerical results for test cases from the medical physics literature are presented.Comment: 20 pages, 7 figure

Multi-locus transcranial magnetic stimulation system for electronically targeted brain stimulation

Background: Transcranial magnetic stimulation (TMS) allows non-invasive stimulation of the cortex. In multi-locus TMS (mTMS), the stimulating electric field (E-field) is controlled electronically without coil movement by adjusting currents in the coils of a transducer. Objective: To develop an mTMS system that allows adjusting the location and orientation of the E-field maximum within a cortical region. Methods: We designed and manufactured a planar 5-coil mTMS transducer to allow controlling the maximum of the induced E-field within a cortical region approximately 30 mm in diameter. We developed electronics with a design consisting of independently controlled H-bridge circuits to drive up to six TMS coils. To control the hardware, we programmed software that runs on a field-programmable gate array and a computer. To induce the desired E-field in the cortex, we developed an optimization method to calculate the currents needed in the coils. We characterized the mTMS system and conducted a proof-of-concept motor-mapping experiment on a healthy volunteer. In the motor mapping, we kept the transducer placement fixed while electronically shifting the E-field maximum on the precentral gyrus and measuring electromyography from the contralateral hand. Results: The transducer consists of an oval coil, two figure-of-eight coils, and two four-leaf-clover coils stacked on top of each other. The technical characterization indicated that the mTMS system performs as designed. The measured motor evoked potential amplitudes varied consistently as a function of the location of the E-field maximum. Conclusion: The developed mTMS system enables electronically targeted brain stimulation within a cortical region. (c) 2021 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer reviewe

Teaching psychology to student nurses: the use of talking heads videos

Psychology is a central part of undergraduate nursing curricula in the UK.However, student nurses report difficulties recognising the relevance and value of psychology. We sought to strengthen first-year student nurses’ application of psychology by developing a set of digital stories based around ‘Talking Head’video clips where authentic patients relate their experiences of illness and nursing care. The aim of this article is to discuss the technological, organisational and pedagogical challenges, student and staff evaluations and our recommendations for the future of Talking Heads. First-year student nurses were shown a video clip of a patient talking about their illness experiences followed by a group learning situation linking main themes to psychology and nursing. Students and staff valued the authenticity of patient’s narrative, found the video clip easy to follow,reported a raised awareness of psychological concepts and improved empathetic understanding of chronic illness. Negative evaluations were related to a sanitised, untypical representation and limited internet access. This small-scale study highlighted how patient narrative may enhance students understanding of illness experience. It chronicles the development and evaluation of a Talking Head in a specific context but which may be useful across disciplines

Reported prevalence of health conditions that affect drivers

Drivers' health and fitness are essential factors in order to predict performance outcomes and to promote road safety. It is a demonstrated fact that drivers with (physical and mental) health impairments or illnesses have more probabilities of being involved in traffic crashes and suffering (or causing) several injuries. The general objective of this study was to examine the prevalence of adverse health conditions that may affect Spanish drivers and its perceived impact on driving fitness. It was used a sample of 1200 Spanish drivers (666 men and 534 women). The only selection criteria were to be in possession of any type of driving license for vehicles other than motorcycles and to drive frequently. As a first result, 42% of the participants considered that sometimes they were not in good health conditions to drive and 1.8% considered it frequently. Furthermore, fatigue, alcohol, negative emotions, drowsiness, headaches, respiratory disease, and fever the most prevalent health conditions impairing driver's fitness. Statistical analysis revealed gender differences in reported health and fitness between male and female drivers. The main cause reported to avoid driving task was to suffer illnesses related to physical health (77.6% of drivers). Based on this study, it can be stated that the Administration should work together with the primary health care system in order to improve drivers' awareness on the risk of driving while suffering symptoms of any common physical or mental illness

High source levels and small active space of high-pitched song in bowhead whales (Balaena mysticetus)

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Public Library of Science, doi:10.1371/journal.pone.0052072.The low-frequency, powerful vocalizations of blue and fin whales may potentially be detected by conspecifics across entire ocean basins. In contrast, humpback and bowhead whales produce equally powerful, but more complex broadband vocalizations composed of higher frequencies that suffer from higher attenuation. Here we evaluate the active space of high frequency song notes of bowhead whales (Balaena mysticetus) in Western Greenland using measurements of song source levels and ambient noise. Four independent, GPS-synchronized hydrophones were deployed through holes in the ice to localize vocalizing bowhead whales, estimate source levels and measure ambient noise. The song had a mean apparent source level of 185±2 dB rms re 1 µPa @ 1 m and a high mean centroid frequency of 444±48 Hz. Using measured ambient noise levels in the area and Arctic sound spreading models, the estimated active space of these song notes is between 40 and 130 km, an order of magnitude smaller than the estimated active space of low frequency blue and fin whale songs produced at similar source levels and for similar noise conditions. We propose that bowhead whales spatially compensate for their smaller communication range through mating aggregations that co-evolved with broadband song to form a complex and dynamic acoustically mediated sexual display.This work was funded by the Oticon Foundation (grant # 08-3469 to Arctic Station, OT). OT and MC were additionally funded by AP Møller og Hustru Chastine Mc-Kinney Møllers Fond til almene Formaal, MS by a PhD scholarship from the Oticon Foundation, FHJ by a Danish Council for Independent Research, Natural Sciences post-doctoral grant, SEP by a grant from the U.S. Office of Naval Research, and PTM by frame grants from the Danish Natural Science Research Council

Examining the Relationship Between Genetic Counselors’ Attitudes Toward Deaf People and the Genetic Counseling Session

Given the medical and cultural perspectives on deafness it is important to determine if genetic counselors’ attitudes toward deaf people can affect counseling sessions for deafness genes. One hundred fifty-eight genetic counselors recruited through the National Society of Genetic Counselors Listserv completed an online survey assessing attitudes toward deaf people and scenario-specific comfort levels discussing and offering genetic testing for deafness. Respondents with deaf/Deaf friends or who work in prenatal or pediatric settings had more positive attitudes toward deaf people than those without deaf/Deaf friends or those working in ‘other’ settings. More positive attitudes toward deaf people correlated with higher comfort level talking about genetic testing for the two scenarios involving culturally Deaf clients; and correlated with higher comfort level offering genetic testing to culturally Deaf clients wishing to have a deaf child. Attitudes and comfort level were not correlated in the scenarios involving hearing or non-culturally deaf clients. These results suggest that genetic counselors’ attitudes could affect information provision and the decision making process of culturally Deaf clients. Cultural sensitivity workshops in genetic counseling training programs that incorporate personal interactions with culturally Deaf individuals are recommended. Additional suggestions for fostering personal interactions are provided