Search asymmetries for threatening faces in chimpanzees (Pan troglodytes)

For primates, the ability to efficiently detect threatening faces is highly adaptive, however, it is not clear exactly how faces are detected. This study investigated whether chimpanzees show search asymmetries for conspecific threatening faces featuring scream and bared teeth expressions. Five adult female chimpanzees participated in a series of touchscreen matching-to-sample visual search tasks. In Experiment 1, search advantages for scream versus neutral targets, and scream versus bared teeth targets were found. A serial search strategy indicated greater difficulty in disengaging attention from scream versus neutral distractors. In Experiments 2a and 2b, search advantages for scream versus neutral targets remained when the mouth was darkened, suggesting that the brightness contrast of the mouth was not critical for the efficient detection of scream targets. In Experiments 3a and 3b, search advantages for inverted scream versus neutral targets disappeared, indicating configural processing. Together, exclusion of the brightness contrast of the mouth as a low-level perceptual confound, and evidence of configural processing, suggested the scream faces may have been perceived as threatening. However, the search advantage for scream faces is most likely explained by the presence of teeth, independently of threat. The study provides further support that an attentional bias towards threatening faces is a homologous trait, which can be traced back to at least the last common ancestor of Old-World monkeys and apes.

Algorithm for computer modeling of combined irrigation systems hydraulic parameters

A feature of combined irrigation systems is the integration of various technologies and methods of irrigation with the implementation of such a possibility on the basis of a single technical system. The hydraulic calculation of such systems is more complicated, since it is assumed that it is possible to implement various modes of operation, which differ by the combination of hydraulic parameters. The operating modes are determined by the combination of the involved irrigation technologies carried out simultaneously. The research has proposed an algorithm for the computer simulation of combined irrigation systems hydraulic parameters. The algorithm implements the principle of step-by-step calculation and formation of statistical screenshots of the hydraulic parameters of the system based on the basic calculated dependencies of classical hydraulics. Static screens can be performed at any time interval, which allows to assess the dynamics of the process under changing external conditions, as well as study the system under different operating modes. The algorithm has built an ingenious system of objects identification, making it possible not only to verify the uniquely defined knots of stems section, but also to organize serial search nodal points in accordance with the architecture of the construction of hydro-reclamation systems.

Limits on semantic prediction in the processing of extraction from adjunct clauses

Processing filler-gap dependencies (‘extraction’) depends on complex top-down predictions. This is observed in comprehenders’ ability to avoid resolving filler-gap dependencies in syntactic island contexts, and in the immediate sensitivity to the plausibility of the resulting interpretation. How complex can these predictions be? In this paper, we examine the processing of extraction from adjunct clauses. Adjunct clauses are argued to be syntactic islands, however, extraction is permitted if the adjunct clause and main clause satisfy specific compositional and conceptual semantic criteria. In an acceptability judgment task, we found that this generalization is robust. Additionally, our results show that this is a property specific to adjunct clauses by comparing adjunct clauses to conjunct VPs, which are similarly argued to permit extraction depending on semantic factors. However, in an A-Maze task, we found no evidence that this knowledge is deployed in real-time sentence processing. Instead, we found that comprehenders attempted to resolve a filler-gap dependency in an adjunct clause regardless of its island status. We propose that this is because deploying this linguistic constraint depends on a second-order serial search over event schemata, which is likely costly and time-consuming. Thus, comprehenders opt for a riskier strategy and attempt resolution into adjunct clauses categorically.

Reliance on central vs. peripheral vision for visual search in younger and older adults

Older adults show declines performing visual search, but their nature is unclear. We propose that it is related to greater attentional reliance on central vision. To investigate this, we tested how occluding central vision would affect younger and older adults in visual search. Participants (14 younger, M = 21.6 years; 16 older, M = 69.6 years) performed pop-out and serial search tasks in full view and with different sized gaze-contingent artificial central scotomas (no scotoma, 3°, 5° or 7° diameter).In pop-out search, older adults showed longer search times for peripheral targets during full viewing. Their reaction times, saccades and fixation durations also increased as a function of scotoma size, contrary to younger adults. These declines may reflect a relative impairment in peripheral visual attention for global processing in aging.In serial search, despite older adults being generally slower, we found no difference between groups in reaction time increases for eccentric targets and for bigger scotomas. These results may come from the difficulty of serial search, in which both groups used centrally limited attentional windows.We conclude that older adults allocate more attentional resources towards central vision compared to younger adults, impairing their peripheral processing primarily in pop-out visual search.

Principles of tactile search over the body

Little is known about how we selectively experience multisite touch patterns over the body. Using a tactile analog of the classic visual target search paradigm, we show that tactile search behavior for flutter cues is generally consistent with a serial search process. Modeling results reveal the preferential contributions of index finger stimulation and two-site stimulus interactions involving ipsilateral patterns and within-limb patterns. Our results offer initial evidence for spatial and temporal principles underlying tactile search behavior over the body.

Deletion of calcineurin from astrocytes reproduces proteome signature of Alzheimer’s disease and epilepsy and predisposes to seizures

ABSTRACTIn astrocytes, calcineurin (CaN) is involved in neuroinflammation and gliosis, while its role in healthy CNS or in early neuro-pathogenesis is poorly understood. Here we report that in astroglial CaN KO (ACN-KO) mice, at one month of age, proteome is deranged in hippocampus and cerebellum. Bioinformatic analysis reveals association with Alzheimer’s disease (AD) and epilepsy. We found significant overlap with the proteome of an AD mouse model and of human subjects with drug-resistant epilepsy. In Barnes maze ACN-KO mice learned the task but adopted serial search strategy. Strikingly, from five months of age ACN-KO mice develop spontaneous seizures with an inflammatory signature of epileptic brains. These results suggest that astroglial CaN KO impairs hippocampal connectivity, produces proteome features of neurological disorders and predisposes mice to seizures. We suggest that astroglial CaN may serve as a novel Ca2+-sensitive switch which regulates protein expression and homeostasis in the CNS.

Performance Analysis of Acquisition Algorithms for Navic

Indian Regional Navigation Satellite System (IRNSS), is an indigenous navigation system designed and developed by ISRO (Indian Space Research Organization).It is named as NavIC, Navigation with Indian Constellation by Indian Prime Minister. NavIC is designed to have seven satellite constellation that provides reliable position, navigation and timing services over India. The focal modules of NavIC receiver are acquisition, tracking and navigation unit. Among them, acquisition is the data processing unit for detecting satellite signals and their corresponding code phase and carrier frequency. In this paper, various acquisition algorithms like Serial search and Parallel Code Phase search algorithms are analyzed and compared with Cooley-Tukey FFT algorithm and sub-sampled Fast Fourier transform (ssFFT).The results obtained in MATLAB shows that the acquisition computation time for ssFFT based NavIC receiver is faster than parallel FFT acquisition and the Cooley-Tukey FFT IRNSS acquisition algorithm is faster and provides better code phase and carrier frequency values compared to serial search acquisition algorithm.

Serial search code acquisition of FHSS system

Frequency hopping spread spectrum (FHSS) communication systems offer significant performance advantages in view of their low probability of intercept, improved performance in multipath fading environments and their ability to avoid interference by hopping into low interference frequency channels. For the transmitted sequence to be correctly received and demodulated, the frequency hop sequence used at the receiver should be similar to that employed in the transmitter. Code acquisition in frequency hopping attempts to address this problem by providing a frequency hop pattern at the receiver that is nearly identical to that used at the transmitter. Code acquisition brings the alignment between the transmitter and the receiver hop pattern to at least one hop period. In this paper, the serial search code acquisition, which is the first step of synchronization, is studied for frequency hopping spread spectrum (HFSS) system over Rayleigh fading channel. Simulation results show the effect of fading channel on the code acquisition.

Principles of tactile search over the body

Although we experience complex patterns over our entire body, how we selectively perceive multi-site touch over our bodies remains poorly understood. Here, we characterized tactile search behavior over the body using a tactile analog of the classic visual search task. Participants judged whether a target stimulus (e.g., 10-Hz vibration) was present or absent on the upper or lower limbs. When present, the target stimulus could occur alone or with distractor stimuli (e.g., 30-Hz vibrations) on other body locations. We varied the number and spatial configurations of the distractors as well as the target and distractor frequencies and measured the impact of these factors on search response times. First, we found that response times were faster on target-present trials compared to target-absent trials. Second, response times increased with the number of stimulated sites, suggesting a serial search process. Third, search performance differed depending on stimulus frequencies. This frequency-dependent behavior may be related to perceptual grouping effects based on timing cues. We constructed models to explore how the locations of the tactile cues influenced search behavior. Our modeling results reveal that, in isolation, cues on the index fingers make relatively greater contributions to search performance compared to stimulation experienced on other body sites. Additionally, co-stimulation of sites within the same limb or simply on the same body side preferentially influence search behavior. Our collective findings identify some principles of attentional search that are common to vision and touch, but others that highlight key differences that may be unique to body-based spatial perception.New & NoteworthyLittle is known about how we selectively experience multi-site touch over the body. Using a tactile analog of the classic visual search paradigm, we show that tactile search behavior for flutter cues is generally consistent with a serial search process. Modeling results reveal the preferential contributions of index finger stimulation and two-site interactions involving ipsilateral and within-limb patterns. Our results offer initial evidence for spatial and temporal principles underlying tactile search behavior over the body.

Repetition Attenuates the Influence of Recency on Recognition Memory: Behavioral and Electrophysiological Evidence

ABSTRACTStudies of recognition memory often demonstrate a recency effect on behavioral performance, whereby response times (RTs) are faster for stimuli that were previously presented recently as opposed to more remotely in the past. This relationship between performance and presentation lag has been taken to reflect that memories are accessed by serially searching backwards in time, such that RT indicates the self-terminating moment of such a process. Here, we investigated the conditions under which this serial search gives way to more efficient means of retrieving memories. Event-related potentials (ERPs) were recorded during a continuous recognition task in which subjects made binary old/new judgments to stimuli that were each presented up to four times across a range of lags. Stimulus repetition and shorter presentation lag both gave rise to speeded RTs, consistent with previous findings, and we novelly extend these effects to a robust latency measure of the left parietal ERP effect associated with retrieval success. Importantly, the relationship between repetition and recency was further elucidated, such that repetition attenuated lag-related differences that were initially present in both the behavioral and neural latency data. These findings are consistent with the idea that a serial search through recent memory can quickly be abandoned in favor of relying on more efficient ‘time-independent’ cognitive processes or neural signals.