Canopy and edge activity of bats in a quaking aspen (Populus tremuloides) forest

2012 ◽  
Vol 90 (7) ◽  
pp. 798-807 ◽  
Author(s):  
T.W. Pettit ◽  
K.T. Wilkins
Keyword(s):  
Populus Tremuloides ◽  
High Frequency ◽  
Regression Tree ◽  
Low Frequency ◽  
Tree Height ◽  
Quaking Aspen ◽  
Activity Levels ◽  
Forest Canopies ◽  
Bat Activity ◽  
Cart Analysis

Characteristics of edges affect the behavior of species that are active in and near edges. Forest canopies may provide edge-like habitat for bats, though bat response to edge orientation has not been well examined. We sampled bat activity in quaking aspen ( Populus tremuloides Michx.) forest canopies and edges in Heber Valley, Utah, during summer 2009 using Anabat detectors. Categorization and regression tree (CART) analysis of echolocation characteristics (e.g., frequency, duration) identified two guilds based on characteristic frequency (i.e., high- and low-frequency guilds). We used linear regression to compare characteristics of canopy and edge vegetation (e.g., tree height, diameter at breast height) to bat activity levels. Activity levels of high-frequency bats did not respond differentially to edge vegetation; low-frequency bat activity seemed to respond to canopy height. Activity levels of high-frequency bats were significantly greater than low-frequency bats in both edges and canopies. We detected significantly more bat activity in forest edges than in forest canopies, indicating the importance of edges to bats in forests.

Do mosquitoes influence bat activity in coastal habitats?

2013 ◽  
Vol 40 (1) ◽  
pp. 10 ◽  
Author(s):  
Leroy Gonsalves ◽  
Susan Lamb ◽  
Cameron Webb ◽  
Bradley Law ◽  
Vaughan Monamy
Keyword(s):  
High Frequency ◽  
Feeding Activity ◽  
Low Frequency ◽  
Coastal Habitats ◽  
Insectivorous Bats ◽  
Diverse Range ◽  
Bat Activity ◽  
Small Prey ◽  
Important Prey ◽  
Forest Habitats

Context Conservation of insectivorous bat populations requires appropriate management of foraging habitats and the prey resources they sustain. Endangered coastal saltmarsh communities support a diverse range of aquatic and terrestrial arthropods, including the saltmarsh mosquito (Aedes vigilax Skuse), an important vector of mosquito-borne viruses and a potentially important prey resource for insectivorous bats. Prey detectability by bats is considered to be limited with low-frequency echolocation, particularly in cluttered habitats, that may render abundant Ae. vigilax populations unavailable to some bat species. Aims To investigate relationships between availability of Ae. vigilax and non-mosquito prey, and the activity of foraging insectivorous bats in a range of coastal habitats. Methods We measured nightly bat activity and the abundance of prey (mosquito and non-mosquito) concurrently during neap and spring tides in saltmarsh, urban and forest habitats. Comparisons were made between tidal cycle and habitats, and relationships between bat activity and the abundance of prey were examined. Key results Whereas prey abundances were generally greatest in saltmarsh and forest habitats, bat activity was greatest in the forest habitat. However, proportional feeding activity was greatest in saltmarsh. Prey abundance was positively correlated with total bat activity only in the open saltmarsh, where an absence of clutter would maximise prey detectability and thus availability. Positive correlations between Ae. vigilax abundance and bat activity, across all habitats, were restricted to bats of the Vespadelus genus, which are small-sized bats that employ high-frequency echolocation suitable for detection of small prey along edges. Conclusions These findings suggest that Ae. vigilax may be an important prey resource for small, high-frequency echolocating bats capable of discerning small prey within cluttered forest as well as exploiting abundant prey in the open saltmarsh. Implications Small, high-frequency echolocating bats should be the focus of future studies investigating the importance of small prey, such as Ae. vigilax, to the diets of foraging bats.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, flexibilidade e variáveis antropométricas em indivíduos sedentários

2016 ◽  
Vol 17 (1) ◽  
pp. 66
Author(s):  
Maria Lina Silva Leite
Keyword(s):  
High Frequency ◽  
Low Frequency

O objetivo deste estudo foi avaliar os efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, na flexibilidade e nas variáveis antropométricas em indivíduos sedentários. O presente estudo contou com 14 voluntárias do sexo feminino, na faixa etária entre 40 e 55 anos, que realizaram 20 sessões de exercícios do Método Pilates, duas vezes por semana, com duração de 45 minutos cada sessão, dividida em três fases: repouso, exercício e recuperação. As variáveis estudadas foram: os dados antropométricos, flexibilidade avaliada utilizando o teste de sentar-e-alcançar com o Banco de Wells, e intervalos R-R usando um cardiotacômetro. O processamento dos sinais da frequência cardíaca foi efetuado em ambiente MatLab 6.1®, utilizando a TWC. Os dados coletados foram submetidos ao teste de normalidade de Shapiro Wilk e foi utilizado o teste de Wilcoxon e Anova One Way (α = 0,05). Nos resultados, observou-se que não houve diferenças significativas entre os valores antropométricos e de frequência cardíaca, porém houve aumento da flexibilidade com o treinamento. Comparando a primeira e a vigésima sessão com relação aos parâmetros low frequency (LF), high frequency (HF), e relação LF/HF, não houve diferença na fase de repouso e foram constatadas diferenças significativas de LF (p = 0,04) e HF (p = 0,04) na fase de exercício e diferença significativa de LF/HF (p = 0,05) na fase de recuperação. Comparando os parâmetros nos períodos de repouso, exercícios e recuperação durante a primeira sessão e durante a vigésima sessão, não houve diferença significativa nos parâmetros LF, HF e LF/HF. Pode-se concluir que, em relação à flexibilidade, foi observada uma melhora significativa, enquanto a análise da frequência cardíaca caracterizou a intensidade do exercício de 50% da capacidade funcional das voluntárias. Em relação aos parâmetros LF, HF e LF/HF foram observados um aumento da variabilidade da frequência cardíaca, provavelmente produto da atividade do Método Pilates. A Transformada Wavelet (TWC) mostrou-se um Método adequado para as análises da variabilidade da frequência cardíaca.Palavras-chave: frequência cardíaca, Transformada Wavelet, Pilates.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

A Novel Adaptive PET/CT Image Fusion Algorithm

2019 ◽  
Vol 14 (7) ◽  
pp. 658-666
Author(s):  
Kai-jian Xia ◽  
Jian-qiang Wang ◽  
Jian Cai
Keyword(s):  
Lung Cancer ◽  
Image Fusion ◽  
High Frequency ◽  
Malignant Tumors ◽  
Low Frequency ◽  
Combination Method ◽  
Ct Image ◽  
Fusion Algorithm ◽  
Pet Ct ◽  
Frequency Components

Background: Lung cancer is one of the common malignant tumors. The successful diagnosis of lung cancer depends on the accuracy of the image obtained from medical imaging modalities. Objective: The fusion of CT and PET is combining the complimentary and redundant information both images and can increase the ease of perception. Since the existing fusion method sare not perfect enough, and the fusion effect remains to be improved, the paper proposes a novel method called adaptive PET/CT fusion for lung cancer in Piella framework. Methods: This algorithm firstly adopted the DTCWT to decompose the PET and CT images into different components, respectively. In accordance with the characteristics of low-frequency and high-frequency components and the features of PET and CT image, 5 membership functions are used as a combination method so as to determine the fusion weight for low-frequency components. In order to fuse different high-frequency components, we select the energy difference of decomposition coefficients as the match measure, and the local energy as the activity measure; in addition, the decision factor is also determined for the high-frequency components. Results: The proposed method is compared with some of the pixel-level spatial domain image fusion algorithms. The experimental results show that our proposed algorithm is feasible and effective. Conclusion: Our proposed algorithm can better retain and protrude the lesions edge information and the texture information of lesions in the image fusion.

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