scholarly journals Increased emission intensity can compensate for the presence of noise in human click-based echolocation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. G. Castillo-Serrano ◽  
L. J. Norman ◽  
D. Foresteire ◽  
L. Thaler
Keyword(s):  
Emission Intensity ◽  
Spectral Power ◽  
Signal To Noise Ratio ◽  
Noisy Environments ◽  
Spectral Components ◽  
Echo Detection ◽  
Long Time ◽  
Potential Strategy ◽  
Reflecting Surface ◽  
First Time

AbstractEcholocating bats adapt their emissions to succeed in noisy environments. In the present study we investigated if echolocating humans can detect a sound-reflecting surface in the presence of noise and if intensity of echolocation emissions (i.e. clicks) changes in a systematic pattern. We tested people who were blind and had experience in echolocation, as well as blind and sighted people who had no experience in echolocation prior to the study. We used an echo-detection paradigm where participants listened to binaural recordings of echolocation sounds (i.e. they did not make their own click emissions), and where intensity of emissions and echoes changed adaptively based on participant performance (intensity of echoes was yoked to intensity of emissions). We found that emission intensity had to systematically increase to compensate for weaker echoes relative to background noise. In fact, emission intensity increased so that spectral power of echoes exceeded spectral power of noise by 12 dB in 4-kHz and 5-kHz frequency bands. The effects were the same across all participant groups, suggesting that this effect occurs independently of long-time experience with echolocation. Our findings demonstrate for the first time that people can echolocate in the presence of noise and suggest that one potential strategy to deal with noise is to increase emission intensity to maintain signal-to-noise ratio of certain spectral components of the echoes.

scholarly journals Decadal changes of surface elevation over permafrost area estimated using reflected GPS signals

2018 ◽  
Vol 12 (2) ◽  
pp. 477-489 ◽  
Author(s):  
Lin Liu ◽  
Kristine M. Larson
Keyword(s):  
Signal To Noise Ratio ◽  
Ground Surface ◽  
Temporal Variations ◽  
Surface Elevation ◽  
Frozen Ground ◽  
Near Surface ◽  
Long Time ◽  
Elevation Changes ◽  
Multipath Signal ◽  
Reflecting Surface

Abstract. Conventional benchmark-based survey and Global Positioning System (GPS) have been used to measure surface elevation changes over permafrost areas, usually once or a few times a year. Here we use reflected GPS signals to measure temporal changes of ground surface elevation due to dynamics of the active layer and near-surface permafrost. Applying the GPS interferometric reflectometry technique to the multipath signal-to-noise ratio data collected by a continuously operating GPS receiver mounted deep in permafrost in Barrow, Alaska, we can retrieve the vertical distance between the antenna and reflecting surface. Using this unique kind of observables, we obtain daily changes of surface elevation during July and August from 2004 to 2015. Our results show distinct temporal variations at three timescales: regular thaw settlement within each summer, strong interannual variability that is characterized by a sub-decadal subsidence trend followed by a brief uplift trend, and a secular subsidence trend of 0.26 ± 0.02 cm year−1 during 2004 and 2015. This method provides a new way to fully utilize data from continuously operating GPS sites in cold regions for studying dynamics of the frozen ground consistently and sustainably over a long time.

Direct imaging of charge transfer

1996 ◽  
Vol 54 ◽  
pp. 680-681
Author(s):  
Yimei Zhu ◽  
J. Tafto
Keyword(s):  
Charge Transfer ◽  
Electron Diffraction ◽  
Scattering Amplitude ◽  
High Temperature Superconductors ◽  
Charge Carriers ◽  
Image Charge ◽  
Net Charge ◽  
Long Time ◽  
Electron Holes ◽  
First Time

The electron holes confined to the CuO2-plane are the charge carriers in high-temperature superconductors, and thus, the distribution of charge plays a key role in determining their superconducting properties. While it has been known for a long time that in principle, electron diffraction at low angles is very sensitive to charge transfer, we, for the first time, show that under a proper TEM imaging condition, it is possible to directly image charge in crystals with a large unit cell. We apply this new way of studying charge distribution to the technologically important Bi2Sr2Ca1Cu2O8+δ superconductors.Charged particles interact with the electrostatic potential, and thus, for small scattering angles, the incident particle sees a nuclei that is screened by the electron cloud. Hence, the scattering amplitude mainly is determined by the net charge of the ion. Comparing with the high Z neutral Bi atom, we note that the scattering amplitude of the hole or an electron is larger at small scattering angles. This is in stark contrast to the displacements which contribute negligibly to the electron diffraction pattern at small angles because of the short g-vectors.

Application of Novel Low Current OBIRCH Amplifier and Nanoprobing to Identify Subtle Leakages in Advanced Node Technologies

2018 ◽  
Author(s):  
Satish Kodali ◽  
Liangshan Chen ◽  
Yuting Wei ◽  
Tanya Schaeffer ◽  
Chong Khiam Oh
Keyword(s):  
Signal To Noise Ratio ◽  
Semiconductor Industry ◽  
Fault Isolation ◽  
Ring Oscillator ◽  
High Signal ◽  
The Novel ◽  
Resistance Change ◽  
Three Samples ◽  
Relative Threshold ◽  
First Time

Abstract Optical beam induced resistance change (OBIRCH) is a very well-adapted technique for static fault isolation in the semiconductor industry. Novel low current OBIRCH amplifier is used to facilitate safe test condition requirements for advanced nodes. This paper shows the differences between the earlier and novel generation OBIRCH amplifiers. Ring oscillator high standby leakage samples are analyzed using the novel generation amplifier. High signal to noise ratio at applied low bias and current levels on device under test are shown on various samples. Further, a metric to demonstrate the SNR to device performance is also discussed. OBIRCH analysis is performed on all the three samples for nanoprobing of, and physical characterization on, the leakage. The resulting spots were calibrated and classified. It is noted that the calibration metric can be successfully used for the first time to estimate the relative threshold voltage of individual transistors in advanced process nodes.

Assessment of recreational use of specially protected natural territories of Tatishchevsky district of Saratov region

2019 ◽  
Vol 27 (2) ◽  
pp. 117-127
Author(s):  
Yulia M Andriyanova ◽  
Irina V Sergeeva ◽  
Yulia M Mokhonko ◽  
Natalia N Gusakova
Keyword(s):  
Natural Resources ◽  
Protected Areas ◽  
Saratov Region ◽  
Future State ◽  
Forest Phytocenoses ◽  
Long Time ◽  
Main Components ◽  
First Time ◽  
Recreational Use ◽  
Specially Protected Natural Territories

The influence of recreation being a set of measures to restore health and recreation, on the main components of forest phytocenoses in specially protected natural territories of the Tatishchevsky district of the Saratov region has been studied for the first time. These phytocenoses have been intensively used for tourism for a long time. The intensity and visits activity of protected areas has been determined; the recreational capacity of territorial objects has been studied. The degree of forest landscapes has been revealed in specially protected natural territories. The findings allow predicting the future state of the natural resources of the Saratov region and can be taken into account when assessing their optimal use.

scholarly journals Frequency-diverse multimode millimetre-wave constant-ϵr lens-loaded cavity

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
M. A. B. Abbasi ◽  
V. F. Fusco ◽  
O. Yurduseven ◽  
T. Fromenteze
Keyword(s):  
Signal To Noise Ratio ◽  
Cost Effective ◽  
Doa Estimation ◽  
Frequency Diversity ◽  
Millimetre Wave ◽  
Single Lens ◽  
Dielectric Lens ◽  
Diversity Principle ◽  
First Time ◽  
Multi Mode

AbstractThis paper presents a physical frequency-diverse multimode lens-loaded cavity, designed and used for the purpose of the direction of arrival (DoA) estimation in millimetre-wave frequency bands for 5G and beyond. The multi-mode mechanism is realized using an electrically-large cavity, generating spatio-temporally incoherent radiation masks leveraging the frequency-diversity principle. It has been shown for the first time that by placing a spherical constant dielectric lens (constant-ϵr) in front of the radiating aperture of the cavity, the spatial incoherence of the radiation modes can be enhanced. The lens-loaded cavity requires only a single lens and output port, making the hardware development much simpler and cost-effective compared to conventional DoA estimators where multiple antennas and receivers are classically required. Using the lens-loaded architecture, an increase of up to 6 dB is achieved in the peak gain of the synthesized quasi-random sampling bases from the frequency-diverse cavity. Despite the fact that the practical frequency-diverse cavity uses a limited subset of quasi-orthogonal modes below the upper bound limit of the number of theoretical modes, it is shown that the proposed lens-loaded cavity is capable of accurate DoA estimation. This is achieved thanks to the sufficient orthogonality of the leveraged modes and to the presence of the spherical constant-ϵr lens which increases the signal-to-noise ratio (SNR) of the received signal. Experimental results are shown to verify the proposed approach.

scholarly journals Clinical significance of late diastolic tissue doppler parameters after onset of STEMI: from the view point of the timing of the echocardipography

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N Iwahashi ◽  
J Kirigaya ◽  
M Horii ◽  
T Abe ◽  
E Akiyama ◽  
...  
Keyword(s):  
Tissue Doppler ◽  
Atrial Function ◽  
Diastolic Velocity ◽  
Long Time ◽  
Group A ◽  
St Elevation ◽  
Group B ◽  
First Time

Abstract Background The early transmitral flow velocity (E) divided by the early diastolic velocity of the mitral valve annulus (e') is referred to as the “E/e' ratio,” is useful even for ST elevation acute myocardial infarction (STEMI). However, the role of late diastolic velocity (a') which reveals the atrial function for STEMI is still unclear. Objectives We evaluated the clinical usefulness of tissue Doppler including atrial function for a first-time STEMI by long time follow up. Furthermore, we evaluated the meaning of each parameters by performing immediately after PCI or 2 weeks later. Methods We treated consecutive 571 first-time STEMI patients by immediate PCI within 12 hours after onset, and we examined 270 patients at immediately after PCI (GroupA, 65 years, 250 male) and 301 patients at 2 weeks after onset (GroupB, 64 years, 243 male). We examined trans mitral flow and TDI, then defined E/e' as LV filling pressure and A/a' as left atrial function. We followed them for a long time (>5 years). The primary end point (PE) was cardiac death or re-admission for heart failure (HF). Results We followed the patients in Group A for 10 years, Group B for 5 years. PE occurred in 64 patients in GroupA during 10 years, and 45 patients in GroupB during 5 years. We analyzed the univariate and multivariate Cox hazard analyses and we compared e' and a', E/e' and A/a' (Table). In GroupA, a' and A/a' were the independent predictors, on the other hand neither a' nor A/a' were the predictors in GroupB. E/e' was an independent predictor both in GroupA and B. Conclusion TDI parameters have different meanings by the timing of echocardiography after onset of a first-time STEMI. These results demonstrated that atrial dysfunction immediately after onset of STEMI suggests the poor prognosis after STEMI. Cox Hazard Proportional Analysis Funding Acknowledgement Type of funding source: None

Neural Correlates of Mathematical Problem Solving

2015 ◽  
Vol 25 (02) ◽  
pp. 1550004 ◽  
Author(s):  
Chun-Ling Lin ◽  
Melody Jung ◽  
Ying Choon Wu ◽  
Hsiao-Ching She ◽  
Tzyy-Ping Jung
Keyword(s):  
Problem Solving ◽  
Spectral Power ◽  
Mathematical Problem ◽  
Neural Correlates ◽  
Mathematical Problem Solving ◽  
Single Digit ◽  
Beta Power ◽  
First Time ◽  
Anterior Posterior ◽  
Arithmetical Problem Solving

This study explores electroencephalography (EEG) brain dynamics associated with mathematical problem solving. EEG and solution latencies (SLs) were recorded as 11 neurologically healthy volunteers worked on intellectually challenging math puzzles that involved combining four single-digit numbers through basic arithmetic operators (addition, subtraction, division, multiplication) to create an arithmetic expression equaling 24. Estimates of EEG spectral power were computed in three frequency bands — θ (4–7 Hz), α (8–13 Hz) and β (14–30 Hz) — over a widely distributed montage of scalp electrode sites. The magnitude of power estimates was found to change in a linear fashion with SLs — that is, relative to a base of power spectrum, theta power increased with longer SLs, while alpha and beta power tended to decrease. Further, the topographic distribution of spectral fluctuations was characterized by more pronounced asymmetries along the left–right and anterior–posterior axes for solutions that involved a longer search phase. These findings reveal for the first time the topography and dynamics of EEG spectral activities important for sustained solution search during arithmetical problem solving.

scholarly journals Patients' anxiety before cardiac catheterization

2010 ◽  
Vol 8 (4) ◽  
pp. 483-487 ◽  
Author(s):  
Leandro Loureiro Buzatto ◽  
Suely Sueko Viski Zanei
Keyword(s):  
Cardiac Catheterization ◽  
Patient Information ◽  
Scientific Publications ◽  
Patient Understanding ◽  
Post Procedure ◽  
Long Time ◽  
On Line ◽  
First Time ◽  
Multiprofessional Approach ◽  
Pharmacologic Therapies

ABSTRACT Objective: To identify researches related to anxiety and strategies to reduce it in patients who are in the pre-cardiac catheterization period. Methods: A bibliographic research was carried out in the on line databases of PubMed, MedLine, CINAHL, LILACS and SciELO, from 1997 to 2009 in MedLine and from 1999 to 2009 in the others databases. The boolean expressions “and” and “or” has been used with the descriptors in Portuguese and in English. The inclusion of discerning was related about the presence, level and workable of the anxiety from the period of pre-cardiac catheterization. Results: Coping most of 17 researches selected were in American scientific publications, with experimental-descriptive studies. The possibilities of intercurrence and/or complications during and post-procedure, diagnostic, possibility of bad prognostic, being alone during the waiting, the first time submission the procedure, lost information and/or orientation and long time waiting could cause anxiety in pre-cardiac catheterization. Maintenance of escort and family alongside the patient, information adapted to the patient understanding level, overcoming traumas and difficulties with a multiprofessional approach, pharmacologic and non pharmacologic therapies were strategies to reduce the anxiety. Conclusions: The nurses are responsible to provide a humanized assistance to offer a fast recuperation, minimize traumas of the hospitalization and the procedure. The knowledge of the causes and the strategies are fundamental to reduce the level of anxiety in pre-catheterization cardiac.

scholarly journals First Results from Insemination With Sex-Sorted Semen in Dairy Heifers in Macedonia

2015 ◽  
Vol 38 (1) ◽  
pp. 107-111
Author(s):  
Ljupche Kochoski ◽  
Zoran Filipov ◽  
Ilcho Joshevski ◽  
Stevche Ilievski ◽  
Filip Davkov
Keyword(s):  
Pregnancy Rate ◽  
Transrectal Ultrasound ◽  
Gestation Length ◽  
Dairy Heifers ◽  
Holstein Friesian ◽  
First Results ◽  
Long Time ◽  
The Usa ◽  
Normal Gestation ◽  
First Time

Abstract Science has been searching for a long time for a reliable method for controlling the sex of mammalian offspring. Recently, the application of specific modern cellular methodologies has led to the development of a flow cytometric system capable of differentiating and separating living X- and Y-chromosome-bearing sperm cells in amounts suitable for AI and therefore, commercialization of this sexing technology. The aim of this work was to present the first results of heifers that introduce bovine AI with sex sorted semen, for the first time in Macedonia. Insemination with sex sorted cryopreserved semen (2×106 spermatozoa per dose) imported from the USA was done at two dairy farms in ZK Pelagonija. In total, 74 heifers (Holstein Friesian) were inseminated. Inseminations were carried out in a timely manner following a modified OvSynch protocol. During the insemination, the sperm was deposited into the uterine horn ipsi lateral to the ovary where a follicle larger than 1.6 cm was detected by means of transrectal ultrasound examination. Pregnancy was checked by ultrasound on day 30 after the insemination. Overall, the average pregnancy rate in both farms was 43,24% (40,54% and 45,95%, for farm 1 and farm 2, respectively). All pregnant heifers delivered their calves following a normal gestation length (274,3 days in average) and of the 32 born calves, 30 (93,75%) were female. In conclusion, since the first results from inseminations with sex-sorted semen in dairy heifers in Macedonia are very promising, the introduction of this technique may bring much benefit to the local dairy sector. Average pregnancy rate seems similar with results obtained following ‘regular’ inseminations, notwithstanding the relatively low number of spermatozoa per insemination dose. Due to the latter, we however recommend inseminations only to be carried out by experienced technicians followinga TAI protocol and ultrasound examinations of the ovaries prior to insemination.

scholarly journals Elephant Herding Optimization for Energy-Based Localization

2018 ◽  
Author(s):  
Sérgio Correia ◽  
Marko Beko ◽  
Luís Cruz ◽  
Slavisa Tomic
Keyword(s):  
Source Localization ◽  
Wireless Sensors ◽  
Performance Comparison ◽  
Sensor Nodes ◽  
Convex Relaxations ◽  
Noisy Environments ◽  
New Approach ◽  
Metaheuristic Methods ◽  
Simulation Results ◽  
First Time

This work addresses the energy-based source localization problem in wireless sensors networks. Instead of circumventing the maximum likelihood (ML) problem by applying convex relaxations and approximations (like all existing approaches do), we here tackle it directly by the use of metaheuristics. To the best of our knowledge, this is the first time that metaheuristics is applied to this type of problems. More specifically an elephant herding optimization (EHO) algorithm is applied. Through extensive simulations, the key parameters of the EHO algorithm are optimized such that they match the energy decay model between two sensor nodes. A detailed analysis of the computational complexity is presented, as well as performance comparison between the proposed algorithm and existing non-metaheuristic ones. Simulation results show that the new approach significantly outperforms the existing solutions in noisy environments, encouraging further improvement and testing of metaheuristic methods.

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