Experimental validation of k-Wave: Nonlinear wave propagation in layered, absorbing fluid media

Models of ultrasound propagation in biologically relevant media have applications in planning and verification of ultrasound therapies and computational dosimetry. To be effective, the models must be able to accurately predict both the spatial distribution and amplitude of the acoustic pressure. This requires that the models are validated in absolute terms, which for arbitrarily heterogeneous media should be performed by comparison with measurements of the acoustic field. In this study, simulations performed using the open-source k-Wave acoustics toolbox, with a measurement-based source definition, were quantitatively validated against measurements of acoustic pressure in water and layered absorbing fluid media. In water, the measured and simulated spatial peak pressures agreed to within 3% under linear conditions and 7% under non-linear conditions. After propagation through a planar or wedge shaped glycerol-filled phantom, the difference in spatial peak pressure was 8.5% and 10.7%, respectively. These differences are within or close to the expected uncertainty of the acoustic pressure measurement. The -6 dB width and length of the focus agreed to within 4% in all cases, and the focal positions were within 0.7 mm for the planar phantom and 1.2 mm for the wedge shaped phantom. These results demonstrate that when the acoustic medium properties and geometry are well known, accurate quantitative predictions of the acoustic field can be made using k-Wave

Kopalnia Brzeszcze 1903-1983

S\u142owa kluczowe: Kopalnia W\u119gla Kamiennego "Brzeszcze"; Brzeszcze \u2013 g\uf3rnictwo 20 w.; historia gospodarcza Polski 20 w.; historia g\uf3rnictwa i hutnictwa na G\uf3rnym \u15al\u105sku; w\u119giel kamienn

Historia kopalni Kr\uf3l w Chorzowie 1791-1945

S\u142owa kluczowe: kopalnia "Kr\uf3l" (K\uf6nigsgrube) w Chorzowie; koncern Skarboferm; G\uf3rno\u15bl\u105skie Zag\u142\u119bie W\u119glowe \u2013 g\uf3rnictwo 18-20 w.; historia gospodarcza Polski 18-20 w.; historia g\uf3rnictwa i hutnictwa na G\uf3rnym \u15al\u105sk

On-the-Fly Calculation of Time-Averaged Acoustic Intensity in Time-Domain Ultrasound Simulations Using a k-Space Pseudospectral Method

OBJECTIVE: This paper presents a method to calculate the average acoustic intensity during ultrasound simulation using a new approach that exploits compression of intermediate results. METHODS: One of the applications of high-intensity focused ultrasound (HIFU) simulations is the calculation of the thermal dose, which indicates the amount of tissue destroyed using a state-of-the-art k-space pseudospectral method. The thermal simulation is preceded by the calculation of the average intensity within the acoustic simulation. Due to the time staggering between the particle velocity and the acoustic pressure used in such simulations, the average intensity calculation is typically executed offline after the acoustic simulation consuming both disk space and time (the data can spread over terabytes). Our new approach calculates the average intensity during the acoustic simulation using the output coefficients of a new compression method which enables resolving the time staggering on-the-fly with huge disk space savings. To reduce RAM requirements, the article also presents a new 40-bit method for encoding compression complex coefficients. RESULTS: Experimental numerical simulations with the proposed method have shown that disk space requirements are up to 99 % lower. The simulation speed was not significantly affected by the approach and the compression error did not affect the prediction accuracy of the thermal dose. CONCLUSION: From the standpoint of supercomputers, the new approach is significantly more economical. SIGNIFICANCE: Saving computing resources increases the chances of real use of acoustic simulations in practice. The method can be applied to signals of a similar character, e.g., for electromagnetic radio waves

Historia g\uf3rnictwa w\u119glowego w Zag\u142\u119biu G\uf3rno\u15bl\u105skim w latach 1914-1945

S\u142owa kluczowe: g\uf3rnictwo w\u119glowe; Zag\u142\u119bie G\uf3rno\u15bl\u105skie 1914-1945; przemys\u142 w\u119glowy Zag\u142\u119bia G\uf3rno\u15bl\u105skiego; w\u119giel kamienny; w\u119giel brunatn

Lighten UP! A community-based group intervention to promote psychological well-being in older adults

Objectives: Aging is often characterized by declines in physical and mental health and increased risk for depression and social isolation. A protective factor that has been found to effectively moderate these phenomena is psychological well-being. The aim of his study was to pilot test a novel group intervention (Lighten UP! program) for the promotion of psychological well-being in older adults living in the community. Methods: Lighten UP! is an eight-week program consisting of 90-minute group session designed to teach participants to identify and savor positive experiences across multiple domains of eudaimonic well-being. It was delivered to a sample of 103 men and women aged 60 or over, that were assessed pre- and post-intervention with Ryff's Psychological Well-being Scale (PWB), Life Satisfaction scale, Geriatric Depression Scale, Symptom Questionnaire, and items measuring sleep complaints and social well-being. Results: At the end of the eight weeks, participants reported significantly increased PWB, life satisfaction, and social well-being along with lower levels of depression and fewer physical symptoms and sleep complaints. These gains were particularly robust for individuals with lower pre-program levels of PWB. Conclusions: This pilot investigation suggests the feasibility of a short group program for enhancing well-being in older adults. Future controlled investigations with long-term follow-up assessment are needed to confirm the effectiveness and sustained benefits of the Lighten UP! program. © 2015 Taylor & Franci

Parasitoids (Hymenoptera) of leaf-spinning moths (Lepidoptera) feeding on Vaccinium uliginosum L. along an ecological gradient in central European peat bogs

Parasitoids of leaf-spinning Lepidoptera associated with two isolated central European peat bogs were investigated. Five families of parasitoid Hymenoptera (Braconidae, Ichneumonidae, Eulophidae, Pteromalidae and Encyrtidae) were recorded. Three categories were recognised: (1) primary parasitoids, (2) facultative hyperparasitoids and (3) obligatory hyperparasitoids. Ten species of Braconidae, five species and seven marked morphospecies among Ichneumonidae, and three species of Chalcidoidea were identified. Despite of some niche-specific (but less host-specific) parasitoids, all these hymenopterans are likely to be generalists and none of them were confirmed to be habitat and/or host specialists. Unlike their eurytopic (opportunistic tyrphoneutral) parasitoids, the Lepidoptera hosts associated with peat bogs are partially highly stenotopic (tyrphobionts and tyrphophiles). The occurrence of parasitoids compared to their potential hosts was structured along an ecological (mesoclimatic) gradient, so most parasitoids were recorded from margins while stenotopic (narrow habitat adaptation) moths were mostly distributed near the centre of the bog habitat