1,171 research outputs found
Echo Delay and Overlap with Emitted Orientation Sounds and Doppler-shift Compensation in the Bat, Rhinolophus ferrumequinum
The compensation of Doppler-shifts by the bat, Rhinolophusferrumequinum,
functions only when certain temporal relations between the echo
and the emitted orientation sound are given. Three echo configurations
were used:
a) Original orientation sounds were electronically Doppler-shifted and
played back either cut at the beginning (variable delay) or at the end (variable
duration) of the echo.
b) Artificial constant frequency echoes with variable delay or duration
were clamped to the frequency of the emitted orientation sound at different
Doppler-shifts.
c) The echoes were only partially Doppler-shifted and the Doppler-shifted
component began after variable delays or had variable durations.
With increasing delay or decreasing duration of the Doppler-shifted echo
the compensation amplitude for a sinusoidally modulated + 3 kHz Dopplershift
(modulation rate 0.08 Hz) decreases for all stimulus configurations
(Figs. 1, 2, 3).
The range of the Doppler-shift compensation system is therefore limited
by the delay due to acoustic travel time to about 4 m distance between
bat and target. In this range the overlap duration of the echo with the
emitted orientation sound is always sufficiently long, when compared with
data on the orientation pulse length during target approach from Schnitzler
(1968) (Fig. 5)
Laryngeal Nerve Activity During Pulse Emission in the CF-FM Bat, Rhinolophus ferrumequinum. I. Superior Laryngeal Nerve (External Motor Branch)
The activity of the external (motor) branch of the superior laryngeal nerve (SLN), innervating the cricothyroid muscle, was recorded in the greater horseshoe bat,Rhinolophus ferrumequinum. The bats were induced to change the frequency of the constant frequency (CF) component of their echolocation signals by presenting artificial signals for which they Doppler shift compensated. The data show that the SLN discharge rate and the frequency of the emitted CF are correlated in a linear manner
Hearing Characteristics and Doppler Shift Compensation in South Indian CF-FM Bats
1. Echolocation pulses, Doppler shift compensation behaviour under laboratory conditions and frequency response characteristics of hearing were recorded inRhinolophus rouxi, Hipposideros speoris andHipposideros bicolor.
2. The frequencies of the constant frequency portions of the CF-FM pulses lie at about 82.8 kHz forR. rouxi from Mahabaleshwar, at 85.2 kHz forR. rouxi from Mysore. Hipposiderid bats have considerably higher frequencies at 135 kHz inH. speoris and 154.5 kHz inH. bicolor. The mean sound durations were 50 ms, 6.4 ms and 4.7 ms, respectively.
3. R. rouxi compensates for Doppler shifts in a range up to typically 4 kHz of positive Doppler shifts (Fig. 2). The Doppler shift compensation behaviour is almost identical to that ofR. ferrumequinum.
4. H. speoris andH. bicolor do not compensate for Doppler shifts under laboratory conditions. Doppler shifts in the echoes induce emission frequency changes which are not correlated to the presented Doppler shifts (Fig. 3).
5. The frequency response characteristics of hearing ofR. rouxi show characteristic sensitivity changes near the bat's reference frequency as also found inR. ferrumequinum. The threshold differences between the low threshold at the reference frequency and a few hundred Hz below are 40 to 50 dB in awake bats (Fig. 5).
6. Frequency sensitivity changes near the emitted CF-frequency of the bats are less pronounced inH. speoris or almost absent inH. bicolor
Foraging behavior and Doppler shift compensation in echolocating hipposiderid bats, I-Iipposideros bicolor and I-Iipposideros speoris
1. Two hipposiderid bats,H. bicolor andH. speoris, were observed in their natural foraging areas in Madurai (South India). Both species hunt close together near the foliage of trees and bushes but they differ in fine structure of preferred hunting space:H. bicolor hunts within the foliage, especially whenH. speoris is active at the same time, whereasH. speoris never flies in dense vegetation but rather in the more open area (Fig. 1, Table 1).
2. Both species emit CF/FM-sounds containing only one harmonic component in almost all echolocation situations. The CF-parts of CF/FM-sounds are species specific within a band of 127–138 kHz forH. speoris and 147–159 kHz forH. bicolor (Tables 2 and 3).
3. H. speoris additionally uses a complex harmonic sound during obstacle avoidance and during laboratory tests for Doppler shift compensation.H. bicolor consistently emits CF/FM-sounds in these same situations (Fig. 2).
4. Both hipposiderid bats respond to Doppler shifts in the returning echoes by lowering the frequency of the emitted sounds (Fig. 3). However, Doppler compensations are incomplete as the emitted frequencies are decreased by only 55% and 56% (mean values) of the full frequency shifts byH. speoris andH, bicolor, respectively.
5. The differences in Doppler shift compensation, echolocating and hunting behavior suggest thatH. speoris is less specialized on echolocation with CF/FM-sounds thanH. bicolor
Collicular Responses to the Frequency Modulated Final Part of Echolocation Sounds in Rhinolophusferrum equinum
Collicular evoked potentials in Rhinolophus ferrum equinum show
very prominent responses to the final frequency modulated part of a acoustic
stimulus, simulating the natural echolocation sound
Stellar populations in a standard ISOGAL field in the Galactic disk
We aim to identify the stellar populations (mostly red giants and young
stars) detected in the ISOGAL survey at 7 and 15micron towards a field (LN45)
in the direction l=-45, b=0.0. The sources detected in the survey of the
Galactic plane by the Infrared Space Observatory are characterized based on
colour-colour and colour-magnitude diagrams. We combine the ISOGAL catalog with
the data from surveys such as 2MASS and GLIMPSE. Interstellar extinction and
distance are estimated using the red clump stars detected by 2MASS in
combination with the isochrones for the AGB/RGB branch. Absolute magnitudes are
thus derived and the stellar populations are identified based on their absolute
magnitudes and their infrared excess. A standard approach to the analysis of
ISOGAL disk observations has been established. We identify several hundred
RGB/AGB stars and 22 candidate young stellar objects in the direction of this
field in an area of 0.16 deg^2. An over-density of stellar sources is found at
distances corresponding to the distance of the Scutum-Crux spiral arm. In
addition, we determine mass-loss rates of AGB-stars using dust radiative
transfer models from the literature.Comment: 48pages, 38 figures, accepted for publication in A &
Evaluation of an Oral Care Program to Improve the Oral Health of Home-Dwelling Older People
The aim of this study was to evaluate the impact of the implementation of an Oral Care Program on home care nurses' attitudes and knowledge about oral health (care) and the impact on older people's oral health. A pre-post study, without a control group, was conducted. A preventive Oral Care Program (OCP) was designed, focusing on home care nurses and older people, in collaboration with dental hygienists. Implementation was measured with questionnaires at baseline and after 6 months for home care nurses; for older people, implementation was measured at baseline and after 3 months with the Oral Health Assessment Tool and a questionnaire about oral (self) care between January 2018 and September 2019. Although the study design has limitations, the oral health of older people improved significantly after 3 months and the OCP was most beneficial for people with full dentures. The OCP improved knowledge and attitude of home care nurses. The program fitted well with the daily work routines of home care nurses. Individual-centered care plans for older people, education of home care nurses and the expertise of the dental hygienists have added value in home care nursing. Future implementations should focus on older people with natural teeth
Анализ условий и технологий эксплуатации магистральной нефтеперекачивающей станции «Раскино»
Объектом исследования является насос нефтяной магистральный. Цель работы – диагностирование общего технического состояния нефтяного магистрального насоса НМ 10000-210 нефтеперекачивающей станции "Раскино", предоставить рекомендации к техническому обслуживанию и ремонту насоса по его фактическому техническому состоянию. Основные конструктивные, технологические и технико-эксплуатационные характеристики: произведен расчет диагностирования технического состояния насосного агрегата нефтеперекачивающей станции "Раскино" на основе статистически обработанных данных, полученных с помощью измерительных приборов.The object of the study is the oil trunk pump. The purpose of the work is to diagnose the overall technical condition of the oil main pump NM 10000-210 of the oil pumping station "Raskino", to provide recommendations for maintenance and to repair of the pump according to its actual technical condition. The main design, technological and technical and operational characteristics: the calculation of the technical condition of the pumping unit of the oil pumping station "Raskino" was made on the basis of statistically processed data obtained with the help of measuring instruments
Tuning exchange bias
This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.The exchange bias shift of the hysteresis loop, HE, in antiferromagnetic/ferromagnetic layer systems can be easily controlled (within certain limits) by cooling in zero field from different magnetization states above the antiferromagnetic Néel temperature, TN. This indicates that for moderate cooling fields, HE is determined by the magnetization state of the ferromagnet at TN, and not by the strength of the cooling field
- …