Desert ants, Cataglyphis, use the sky's pattern of polarized light as a compass reference for navigation. However, they do not fully exploit the complexity of this pattern, rather - as proposed previously - they assess their walking direction by means of an approximate solution based on a simplified internal template. ...

Because the environment often includes multiple sounds that overlap in time, listeners must segregate a sound of interest (the auditory figure) from other co-occurring sounds (the unattended auditory ground). We conducted a series of experiments to clarify the principles governing the extraction of auditory figures. We distinguish between auditory "objects" ...

Bacterial production of visible light is a natural phenomenon occurring in marine (Vibrio and Photobacterium) and terrestrial (Photorhabdus) species. The mechanism underpinning light production in these organisms is similar and involves the oxidation of an aldehyde substrate in a reaction catalysed by the bacterial luciferase enzyme. The genes encoding the ...

This paper presents a new in vitro wear simulator based on spatial parallel kinematics and a biologically inspired implicit force/position hybrid controller to replicate chewing movements and dental wear formations on dental components, such as crowns, bridges or a full set of teeth. The human mandible, guided by passive structures ...

The temporal distribution and spatial pattern of abundance of mosquito vectors of Rift Valley fever (RVf) and West Nile fever (WNf) were studied during the 2005 and 2006 rainy seasons at Barkedji, Senegal. Mosquitoes were collected every two weeks with CDC light traps with dry ice at 79 sites including ...

Abstract. Vector control programs could be more efficient by identifying the location of highly productive sites of Aedes aegypti. This study explored if the number of female adults of Ae. aegypti in BG-Sentinel traps was clustered and if their spatial distribution changed in time in two neighborhoods in San Juan, ...

Underwater acoustic vector sensors, for measuring acoustic intensity, are typically used in open water where electromagnetic interference (EMI) is generally not a contributor to overall background noise. However, vector sensors are also useful in a laboratory setting where EMI can be a limiting factor at low frequencies. An underwater vector ...

Squeaking is reported for ceramic-on-ceramic hip arthroplasty, and risk factors leading to this phenomenon have been investigated empirically in the past, this way giving hints to when this phenomenon occurs. The aim of this study is to present an experimentally validated explanation for the dynamical mechanism underlying the squeak, i.e. ...

OBJECTIVE: The purpose of this study was to elucidate the rotation axes of the slow and quick phase of the caloric nystagmus using the video-oculograhic technique. METHODS: Subjects were placed in a supine position and cold-water stimulation was applied to the right ear canal. The eye movements were recorded in ...

In order to accurately localize an object, human observers must integrate multiple sensory cues related to the environment and/or to the body. Such multisensory integration must be repeated over time, so that spatial localization is constantly updated according to environmental changes. In the present experimental study, we examined the multisensory ...

The International Organization for Standardization (ISO) was used to evaluate antibacterial activity by titanium dioxide (TiO(2)) photocatalysis since 2006. We evaluated photocatalytic inactivation of Qβ and T4 bacteriophages induced by low-intensity, long-wavelength ultraviolet A (UVA; 0.1 mW cm(-2) and 0.001 mW cm(-2)) irradiation on a TiO(2)-coated glass plate using the ...

ABSTRACT The authors examined whether the diminished online control of antisaccades is related to a trade-off between movement planning and control or the remapping of target properties to a mirror-symmetrical location (i.e., vector inversion). Pro- and antisaccades were examined in a standard no-delay schedule wherein target onset served as the ...

Despite decades of research devoted to the study of inferior colliculus (IC) neurons' tuning to sound-source azimuth, there remain many unanswered questions because no previous study examined azimuth tuning over a full range of 360° azimuths at a wide range of stimulus levels in an unanesthetized preparation. Furthermore, a comparison ...

This study aims to determine an optimum estimate for the gravitational vector and vertical acceleration profiles using a body-worn tri-axial accelerometer during falls and normal activities of daily living (ADL), validated using a camera based motion analysis system. Five young healthy subjects performed a number of simulated falls and normal ...

In arboreal animals such as the grey mouse lemur (Microcebus murinus Miller, 1777), leaping is the most frequent strategy for predator avoidance. The aim of this study was to characterise the locomotor adaptation in response to the structural constraint of the habitat (i.e., position of the landing substrate). Thus, we ...

Many insects use the polarization pattern of the sky for obtaining compass information during orientation or navigation. E-vector information is collected by a specialized area in the dorsal-most part of the compound eye, the dorsal rim area (DRA). We tested honeybees' capability of learning certain e-vector orientations by using a ...

Cercospora zeae-maydis causes gray leaf spot of maize, which has become one of the most widespread and destructive diseases of maize in the world. C. zeae-maydis infects leaves through stomata, which is predicated on the ability of the pathogen to perceive stomata and reorient growth accordingly. In this study, the ...

ABSTRACT: BACKGROUND: The emergence and massive spread of bluetongue in Western Europe during 2006-2008 had disastrous consequences for sheep and cattle production and confirmed the ability of Palaearctic Culicoides (Diptera: Ceratopogonidae) to transmit the virus. Some aspects of Culicoides ecology, especially host-seeking and feeding behaviors, remain insufficiently described due to ...

The primate superior colliculus (SC) is important for the winner-take-all selection of targets for orienting movements. Such selection takes time, however, and the earliest motor responses typically are guided by a weighted vector average of the visual stimuli, before the winner-take-all selection of a single target. We tested whether SC ...

This study compared the spatial and temporal patterns of Culex tarsalis Coquillett and Aedes vexans Meigen populations and examined their relationships with land cover types and climatic variability in Sioux Falls, SD. Between 24 and 30 CDC CO2-baited light traps were set annually in Sioux Falls from May to September ...

OBJECTIVE: I sought to demonstrate a new device that measures the pulling on an infant during a vaginal delivery. STUDY DESIGN: The Peisner Platform (US Patent 6,684,165; Canadian patent 2,436,154) utilizes Newton's Third Law to measure the force/vector of delivering a baby. Ten patients at term with a singleton fetus ...

Crickets produce stridulated sounds by rubbing their forewings together. The calling song of the cricket species Eneoptera guyanensis Chopard, 1931 alternates two song sections, at low and high dominant frequencies, corresponding to two distinct sections of the stridulatory file. In the present study we address the complex acoustic behavior of ...

Damien Foundation Bangladesh tuberculosis (TB) control projects. To compare blue ink, potassium permanganate and methylene blue background staining for transmitted light-emitting diode (LED) TB fluorescence microscopy (FM). Auramine smears made in triplicate from Ziehl-Neelsen (ZN) acid-fast bacilli (AFB) positive or negative sputum and stained with one of the background variations ...

The tuning of a linear filter may be inferred from the filter's isoresponse (e.g., tuning curves) or isoinput (e.g., isolevel curves) characteristics. This paper provides a theoretical demonstration that for nonlinear filters with compressive response characteristics like those of the basilar membrane, isoresponse measures can suggest strikingly sharper tuning than ...

This investigation was designed to analyze the time-trial (STT) in an international cross-country skiing sprint skating competition for (1) overall STT performance and relative contributions of time spent in different sections of terrain, (2) work rate and kinematics on uphill terrain, and (3) relationships to physiological and kinematic parameters while ...

The role of different spatial frequency bands on face gender and expression categorization was studied in three experiments. Accuracy and reaction time were measured for unfiltered, low-pass (cut-off frequency of 1 cycle/deg) and high-pass (cutoff frequency of 3 cycles/deg) filtered faces. Filtered and unfiltered faces were equated in root-mean-squared contrast. ...

To assess the impact of blue-light filtering on retinal processing to evaluate potential side effects of these filters on visual function at the neural level. Department of Ophthalmology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany. Cohort study. Multifocal electroretinograms (ERGs) were recorded monocularly after pupil dilation in pseudophakic patients with a colorless intraocular ...

The intelligibility of sentences processed to remove temporal envelope information, as far as possible, was assessed. Sentences were filtered into N analysis channels, and each channel signal was divided by its Hilbert envelope to remove envelope information but leave temporal fine structure (TFS) intact. Channel signals were combined to give ...

The contribution of envelope cues at different rates to intelligibility in a competing-speech task was measured as a function of the short-term envelope level. The target and background mixture was processed using tone vocoders. Envelope signals for each vocoder channel were simultaneously extracted with two low-pass filters, the cutoff frequency ...

In this paper, a new fuzzy filter for the removal of random impulse noise in color video is presented. By working with different successive filtering steps, a very good tradeoff between detail preservation and noise removal is obtained. One strong filtering step that should remove all noise at once would ...

Analog filtering and digital signal processing algorithms in the preprocessing modules of an electrocardiographic device play a pivotal role in providing high-quality electrocardiogram (ECG) signals for analysis, interpretation, and presentation (display, printout, and storage). In this article, issues relating to inaccuracy of ECG preprocessing filters are investigated in the context ...

INTRODUCTION: The high output of night vision goggles (NVGs) can cause a loss of dark adaptation, resulting in suboptimal unaided vision. Optical filters have been designed to mitigate this problem by changing the overall output characteristics of the NVGs. METHODS: Several aspects of visual performance related to NVG use were ...

In a previous study, three crosstalk cancellation techniques were evaluated and compared under different conditions. Least-squares approximations in the frequency and time domain were evaluated along with a method based on minimum-phase decomposition and a frequency independent delay. In general, the least-squares methods outperformed the method based on the minimum-phase ...

To provide outcome data relating to cleaning of rigid sigmoidoscopy equipment comparing commonly used techniques, allowing a framework for general guidelines for use in clinical practice. A total of 104 rigid sigmoidoscopies were performed in the rooms of two colorectal surgeons using standard techniques. A three-way randomization was performed adopting ...

In this paper we propose a new structure of the instrumentation for electrocardiographic fetal monitoring. We apply a single-channel approach to maternal electrocardiogram suppression in the recorded four abdominal bioelectric signals. Then we exploit spatial and temporal properties of the extracted four-channel fetal electrocardiogram to construct a new channel with ...

Ecologically valid signals (e.g., vowels) have multiple components of substantially different frequencies and amplitudes that may not be equally cortically represented. In this study, we investigate a relatively simple signal at an intermediate level of complexity, two-frequency composite tones, a stimulus lying between simple sinusoids and ecologically valid signals such ...

Big brown bats emit FM biosonar sounds containing two principal harmonics (FM1 approximately 55-22 kHz;FM2 approximately 105-45 kHz). To examine the role of harmonics, they were selectively filtered from stimuli in electronic-echo delay discrimination experiments. Positive stimuli were delayed by 3.16 ms (55 cm simulated target range); negative stimuli were ...

This article investigates the possibility of extracting gastric motility (GM) information from finger photoplethysmographic (PPG) signals non-invasively. Now-a-days measuring GM is a challenging task because of invasive and complicated clinical procedures involved. It is well-known that the PPG signal acquired from finger consists of information related to heart rate and ...

A directionally selective multilayer filter is applied to a hydrogenated amorphous silicon solar cell to improve the light trapping. The filter prevents non-absorbed long-wavelength photons from leaving the cell under oblique angles leading to an enhancement of the total optical path length for weakly absorbed light within the device by ...

Receiver sensory abilities can be influenced by a number of factors, including habitat, phylogeny and the selective pressure to acquire information about conspecifics or heterospecifics. It has been hypothesized that brood-parasitic brown-headed cowbird (Molothrus ater) females may locate or determine the quality of potential hosts by eavesdropping on their sexual ...

We analyze the reproduction of light fields on multiview 3D displays. A three-way interaction between input light field signal (which is often aliased), joint spatio-angular sampling grids of multiview 3D displays, and inter-view light leakage in modern multiview 3D displays is characterized in the joint spatio-angular frequency domain. Reconstruction of ...

Abstract Brain-computer interfaces (BCIs) based on steady-state visual evoked potentials (SSVEPs) require minimal user training and can offer higher information throughput compared to other BCI modalities. We focused on SSVEPs elicited by high-frequency stimuli (>30 Hz) because they cause minimal fatigue/annoyance and reduce the risk of inducing photoepileptic seizures. This ...

This paper deals with the measurement of frequency-dependent ultrasonic attenuation in strongly heterogeneous materials, such as cementitious materials. To improve the measurement of this parameter on this kind of materials, a linear swept-frequency signal is used to drive an emitter transducer to conduct a through-transmission inspection in immersion. To filter ...

Efforts of phase and amplitude retrieval from diffraction patterns have almost exclusively been applied for nonperiodic objects. We investigated the quality of retrieval of nonperiodic objects embedded in a sinusoidal background, using the approach of iterative hybrid input-output with oversampling. Two strategies were employed; one by filtering in the frequency ...

The effect of different colored filters and atmospheres on photooxidation and quality in milk was studied. Pasteurized bovine milk (3.9% fat) was packed in 2 different atmospheres (air and N(2)) and exposed to light for 20 h at 4 degrees C under 8 transparent filters with different light transmission properties. ...

To make efficient use of their limited signaling capacity, sensory systems often use predictive coding. Predictive coding works by exploiting the statistical regularities of the environment--specifically, by filtering the sensory input to remove its predictable elements, thus enabling the neural signal to focus on what cannot be guessed. To do ...

Low-pass filtering is often applied to eliminate effects of environmental noise when preparing voice recordings for acoustic analysis. This study tested the effects of low-pass filter cutoff frequency on the results of acoustic voice analysis, with a particular interest in the effects of low cutoff frequencies on nonlinear dynamic parameters. ...

The surface electromyographic (sEMG) signal that originates in the muscle is inevitably contaminated by various noise signals or artifacts that originate at the skin-electrode interface, in the electronics that amplifies the signals, and in external sources. Modern technology is substantially immune to some of these noises, but not to the ...

The delayless frequency-domain implementation of least mean squares (LMS) algorithm is attractive because it can eliminate undesired block delay in the signal path while still remain the advantages of the frequency-domain LMS algorithm. However, the conventional delayless frequency-domain LMS experiences difficulties in slow convergence when it is applied to harmonic ...

A methodology for probabilistic bioacoustic signal extraction within spectrograms of natural sound recordings is proposed. Probabilistic models of signal attributes are described for generating a host of likelihoods used to estimate the probability that individual pixels within a spectrogram represent part of a bioacoustic signal. The pixel probabilities result in ...