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Imadudina, Annisaa Hammidah, Widiyanto Hari Subagyo Widodo e Agustina Nurul Hidayati. "Land Use Predictions To The Response Of Kediri Airport". Jurnal Spatial Wahana Komunikasi dan Informasi Geografi 22, n. 1 (31 marzo 2022): 13–22. http://dx.doi.org/10.21009/spatial.221.1.
Testo completoAbstract (sommario):
Kediri Regency is a district with sufficient development with the existence of PSN for the construction of Kediri Airport. Kediri Airport was finally designated as PSN. This Rp 10 trillion airport is included in PSN in accordance with Presidential Regulation Number 56 of 2018. After Kediri Airport, Immediately Build the Kertosono-Tulungagung Toll Road. Land Acquisition for the Kediri Section is Completed in 2021. With this national strategic project, investment development in Kediri Regency will definitely increase. Based on the above, it is very necessary to predict future land use to be able to know the response of land use to the integrated airport and toll road project. The methods used in this research are remote sensing, GIS analysis, cellular automata analysis and descriptive analysis. Knowing the spatial response will be a very meaningful input for planners, especially in formulating plans to maximize the multiplier effect caused by the airport and toll roads on the surrounding space.
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Ansorge, Ulrich. "Spatial intention–response compatibility". Acta Psychologica 109, n. 3 (marzo 2002): 285–99. http://dx.doi.org/10.1016/s0001-6918(01)00062-2.
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MÜSSELER, JOCHEN, GISA ASCHERSLEBEN, KATRIN ARNING e ROBERT W. PROCTOR. "Reversed effects of spatial compatibility in natural scenes". American Journal of Psychology 122, n. 3 (1 ottobre 2009): 325–36. http://dx.doi.org/10.2307/27784406.
Testo completoAbstract (sommario):
Abstract Effects of spatial stimulus–response compatibility are often attributed to automatic position-based activation of the response elicited by a stimulus. Three experiments examined this assumption in natural scenes. In Experiments 1 and 2, participants performed simulated driving, and a person appeared periodically on either side of the road. Participants were to turn toward a person calling a taxi and away from a person carelessly entering the street. The spatially incompatible response was faster than the compatible response, but neutral stimuli showed a typical benefit for spatially compatible responses. Placing the people further in the visual periphery eliminated the advantage for the incompatible response and showed an advantage for the compatible response. In Experiment 3, participants made left–right joystick responses to a vicious dog or puppy in a walking scenario. Instructions were to avoid the vicious dog and approach the puppy or vice versa. Results again showed an advantage for the spatially incompatible response. Thus, the typically observed advantage of spatially compatible responses was reversed for dangerous situations in natural scenes.
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Yin, Ling Xiao, e Jing Ling Chen. "Spin Spatial Frequency Response of Atomic Magnetometer". Key Engineering Materials 787 (novembre 2018): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.787.81.
Testo completoAbstract (sommario):
We describe a method for measuring the spin spatial frequency response in a Cs vapor cell by using a digital micro-mirror device (DMD) to modulate the pumping light both spatially and temporally. An equivalent space-alternative magnetic field is created by this way. The pumping light through the Cs vapor cell is measured and analyzed in spatial frequency domain. We obtain the spatial frequency response of the Cs vapor cell from 1.4 cm-1to 364.9 cm-1. The theoretical results of the spatial frequency response according to Fick's second diffusion law agree with the experimental results. This method provides an alternate approach for spatial characterization and three-dimensional imaging of spins.
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Marini, Maddalena, Cristina Iani, Roberto Nicoletti e Sandro Rubichi. "Between-Task Transfer of Learning From Spatial Compatibility to a Color Stroop Task". Experimental Psychology 58, n. 6 (1 gennaio 2011): 473–79. http://dx.doi.org/10.1027/1618-3169/a000115.
Testo completoAbstract (sommario):
Responses to a relevant stimulus dimension are faster and more accurate when the stimulus and response spatially correspond compared to when they do not, even though stimulus position is irrelevant (Simon effect). It has been demonstrated that practicing with an incompatible spatial stimulus-response (S-R) mapping before performing a Simon task can eliminate this effect. In the present study we assessed whether a learned spatially incompatible S-R mapping can be transferred to a nonspatial conflict task, hence supporting the view that transfer effects are due to acquisition of a general “respond to the opposite stimulus value” rule. To this aim, we ran two experiments in which participants performed a spatial compatibility task with either a compatible or an incompatible mapping and then transferred, after a 5 min delay, to a color Stroop task. In Experiment 1, responses were executed by pressing one of two keys on the keyboard in both practice and transfer tasks. In Experiment 2, responses were manual in the practice task and vocal in the transfer task. The spatially incompatible practice significantly reduced the color Stroop effect only when responses were manual in both tasks. These results suggest that during practice participants develop a response-selection strategy of emitting the alternative spatial response.
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Mareschal, Isabelle, e Curtis L. Baker. "Temporal and Spatial Response to Second-Order Stimuli in Cat Area 18". Journal of Neurophysiology 80, n. 6 (1 dicembre 1998): 2811–23. http://dx.doi.org/10.1152/jn.1998.80.6.2811.
Testo completoAbstract (sommario):
Mareschal, Isabelle and Curtis L. Baker, Jr. Temporal and spatial response to second-order stimuli in cat area 18. J. Neurophysiol. 80: 2811–2823, 1998. Approximately one-half of the neurons in cat area 18 respond to contrast envelope stimuli, consisting of a sinewave carrier whose contrast is modulated by a drifting sinewave envelope of lower spatial frequency. These stimuli should fail to elicit a response from a conventional linear neuron because they are designed to contain no spatial frequency components within the cell's luminance-defined frequency passband. We measured neurons' responses to envelope stimuli by varying both the drift rate and spatial frequency of the contrast modulation. These data were then compared with the same neurons' spatial and temporal properties obtained with luminance-defined sinewave gratings. Most neurons' responses to the envelope stimuli were spatially and temporally bandpass, with bandwidths comparable with those measured with luminance gratings. The temporal responses of these neurons (temporal frequency tuning and latency) were systematically slower when tested with envelope stimuli than with luminance gratings. The simplest kind of model that can accommodate these results is one having separate, parallel streams of bandpass processing for luminance and envelope stimuli.
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Wang, Yu-Xia, e Wan-Tong Li. "Spatial degeneracy vs functional response". Discrete and Continuous Dynamical Systems - Series B 21, n. 8 (settembre 2016): 2811–37. http://dx.doi.org/10.3934/dcdsb.2016074.
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Robinson, L. F., T. D. Wager, L. Y. Atlas e M. A. Lindquist. "Spatial Clustering of Response Curves". NeuroImage 47 (luglio 2009): S102. http://dx.doi.org/10.1016/s1053-8119(09)70885-7.
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McGough, Robert J. "Incorporating the effect of frequency-independent attenuation within the on-axis spatial impulse response of a circular piston". Journal of the Acoustical Society of America 155, n. 3_Supplement (1 marzo 2024): A27. http://dx.doi.org/10.1121/10.0026669.
Testo completoAbstract (sommario):
The spatial impulse response is important for numerical simulations of diagnostic ultrasound. The spatial impulse response, which describes transient diffraction due to an impulsive input, yields closed form analytical expressions for various transducer geometries when the medium is lossless. These analytical expressions are advantageous for simulations that repeatedly evaluate these expressions at hundreds of thousands of points. However, spatial impulse responses evaluated for lossy materials typically require additional numerical calculations that substantially increase the computation time. Thus, analytical or rapidly converging numerical expressions for the lossy spatial impulse response are expected to greatly enhance present simulation methods. This motivates the derivation of on-axis spatial impulse responses for a circular piston that model frequency-independent attenuation. Closed-form analytical expressions for the on-axis spatial impulse response are introduced for two closely related frequency-independent attenuation models. The results show that, as the attenuation constant increases, the peak amplitudes of these lossy on-axis spatial impulse responses decrease. The lossy on-axis impulse response also decreases slightly as time increases beyond the initial arrival time, whereas the lossless on-axis spatial impulse response for a circular piston maintains a constant value after the initial arrival time.
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Müller, Sven, e Knut Haase. "Local revenue response to service quality: spatial effects in seasonal ticket revenue data". European Journal of Marketing 49, n. 9/10 (14 settembre 2015): 1391–416. http://dx.doi.org/10.1108/ejm-10-2013-0531.
Testo completoAbstract (sommario):
Purpose – This paper aims to consider spatial effects in the analysis of the relationship of revenue and service quality. When firms’ customers are located in spatially dispersed areas, it can be difficult to manage service quality on a geographically small scale because the relative importance of service quality might vary spatially. Moreover, standard approaches discussed so far in the marketing science literature usually neglect spatial effects, such as spatial dependencies (e.g. spatial autocorrelation) and spatial drift (spatial non-stationarity). Design/methodology/approach – The authors propose a comprehensive but intelligible approach based on spatial econometric methods that cover spatial dependencies and spatial drift simultaneously. In particular, they incorporate the spatial expansion method (spatial drift) into spatial econometric models (e.g. spatial lag model). Findings – Using real company data on seasonal ticket revenue (dependent variable) and service quality (independent variables) of a regional public transport service provider, the authors find that the elasticity for the length of the public transport network is between 0.2 and 0.5, whereas the elasticity for the headway is between −0.2 and 0.6, for example. The authors control for several socio-economic, socio-demographic and land-use variables. Practical implications – Based on the empirical findings, the authors show that addressing spatial effects of service data can improve management’s ability to implement programs aimed at enhancing seasonal ticket revenue. Therefore, they derive a spatial revenue response function that enables managers to identify small-scale areas that are most efficient in terms of increasing revenue by service improvement. Originality/value – The paper addresses the need to account for spatial effects in revenue response functions of public transport companies.
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Tong, Lillian, William Guido, Nina Tumosa, Peter D. Spear e Susan Heidenreich. "Binocular interactions in the cat's dorsal lateral geniculate nucleus, II: Effects on dominant-eye spatial-frequency and contrast processing". Visual Neuroscience 8, n. 6 (giugno 1992): 557–66. http://dx.doi.org/10.1017/s0952523800005654.
Testo completoAbstract (sommario):
AbstractThe present study tested the hypothesis that nondominant-eye influences on lateral geniculate nucleus (LGN) neurons affect the processing of spatial and contrast information from the dominant eye. To do this, we determined the effects of stimulating the nondominant eye at its optimal spatial frequency on the responses of LGN cells to sine-wave gratings of different spatial frequency and contrast presented to the dominant eye. Detailed testing was carried out on 49 cells that had statistically significant responses to stimulation of the nondominant eye alone.Spatial-frequency response functions to nondominant-eye stimulation indicated that the responses were spatially tuned, as reported previously (Guido et al., 1989). Optimal spatial frequencies through the nondominant eye were significantly correlated with the optimal spatial frequencies through the dominant eye (r = 0.54; P < 0.0001), and the optimal spatial frequencies were fairly similar for the two eyes.Nondominant-eye stimulation changed the maximal amplitude of the fundamental (Fl) response to dominant-eye stimulation for only about 45% (22 of 49) of the cells that responded to nondominant-eye stimulation alone. The response vs. contrast function through the dominant eye was altered for 73% of the cells (51% independent of spatial frequency). Three types of effects were observed: a change in the initial slope of the response vs. contrast function (contrast gain), a change in the response amplitude at which saturation occurred, or an overall change in response at all contrasts. The incidence of these changes was similar for X and Y cells in LGN layers A, Al, and C (only four W cells were tested).Nondominant-eye stimulation had little or no effect on the sizes or sensitivities of the receptive-field centers or surrounds for the dominant eye. In addition, nondominant-eye stimulation had little or no effect on optimal spatial frequency, spatial resolution, or the bandwidth of spatial-frequency contrast sensitivity curves for the dominant eye.Possible functions of binocular interactions in the LGN are considered. The present results suggest a role in interocular contrast-gain control. Interocular contrast differences can occur before the acquisition of binocular fusion, when the two eyes are viewing different aspects of a visual stimulus. Psychophysical and physiological studies suggest that an interocular mechanism exists to maintain relatively constant binocular interactions despite differences in interocular contrast. The present results suggest that at least part of this mechanism occurs in the LGN.
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Tlauka, Michael, e Frank P. McKenna. "Hierarchical Knowledge Influences Stimulus-Response Compatibility Effects". Quarterly Journal of Experimental Psychology Section A 53, n. 1 (febbraio 2000): 85–103. http://dx.doi.org/10.1080/713755880.
Testo completoAbstract (sommario):
The influence of spatial stimulus grouping on stimulus-response compatibility effects was investigated in three experiments. Stimuli were grouped as part of a superordinate unit BY (1) perceptually organizing them (Experiment 1), (2) organizing them on the basis of semantic links (Experiment 2), or (3) arbitrary links (Experiment 3). In some instances the arrangement of the stimuli resulted in a conflict between two types of spatial relationship: one between stimulus and response and the other between superordinate unit and response. The experiments indicated that it was the latter relationship that mainly determined performance in the experiments. Reaction time analyses showed that responses were fastest if they spatially corresponded to the relative location of the superordinate unit of which the stimulus was part. The results are discussed with reference to hierarchical accounts of coding stimulus information.
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Praamstra, P., e F. M. Plat. "Failed Suppression of Direct Visuomotor Activation in Parkinson's Disease". Journal of Cognitive Neuroscience 13, n. 1 (1 gennaio 2001): 31–43. http://dx.doi.org/10.1162/089892901564153.
Testo completoAbstract (sommario):
The response times in choice-reaction tasks are faster when the relative spatial positions of stimulus and response match than when they do not match, even when the spatial relation is irrelevant to response choice. This spatial stimulus—response (S-R) compatibility effect (i.e., the Simon effect) is attributed in part to the automatic activation of spatially corresponding responses, which need to be suppressed when the spatial location of stimulus and correct response do not correspond. The present study tested patients with Parkinson's disease and healthy control subjects in a spatial S-R compatibility task in order to investigate whether basal ganglia dysfunction in Parkinson's disease leads to disinhibition of direct visuomotor activation. High-density event-related brain potential recordings were used to chart the cortical activity accompanying attentional orientation and response selection. Response time measures demonstrated a failure to inhibit automatic response activation in Parkinson patients, which was revealed by taking into account a sequence-dependent modulation of the Simon effect. Event-related potential (ERP) recordings demonstrated that visuospatial orientation to target stimuli was accompanied by signal-locked activity above motor areas of the cortex, with similar latencies but an enhanced amplitude in patients compared to control subjects. The results suggest that inhibitory modulation of automatic, stimulus-driven, visuomotor activation occurs after the initial sensory activation of motor cortical areas. The failed inhibition in Parkinson's disease appears therefore related to a disturbance in processes that prevent early attention-related visuomotor activation, within motor areas, from actually evoking a response.
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Frans, E. P., e R. A. Schowengerdt. "Improving Spatial-Spectral Unmixing with the Sensor Spatial Response Function". Canadian Journal of Remote Sensing 25, n. 2 (giugno 1999): 131–51. http://dx.doi.org/10.1080/07038992.1999.10874712.
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Lopez, Víctor, Arturo González-Vega, Alberto Aguilar, J. E. A. Landgrave e Jorge García-Márquez. "Non-uniform spatial response of the LCoS spatial light modulator". Optics Communications 366 (maggio 2016): 419–24. http://dx.doi.org/10.1016/j.optcom.2015.12.058.
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Baro, John A., e Stephen Lehmkuhle. "The effects of a luminanace-modulated background on the grating-evoked cortical potential in the cat". Visual Neuroscience 3, n. 6 (dicembre 1989): 563–72. http://dx.doi.org/10.1017/s0952523800009895.
Testo completoAbstract (sommario):
AbstractAveraged grating-evoked cortical potentials were recorded from area 17 of awake cats. Peak latency of early components of the visual-evoked potential (VEP) response to stimulus onset increased as a function of spatial frequency, while amplitude tended to be largest at intermediate spatial frequencies. Latency increased and amplitude generally decreased to lower spatial-frequency stimuli (<0.25 cycle/deg) in the presence of a uniform flickering field (UFF). The UFF had a relatively small or opposite effect on peak latency and amplitude for higher spatial-frequency stimuli (>0.50 cycle/deg). The VEP response to stimulus offset was present only at low spatial frequencies and was virtually eliminated by the presence of the UFF. The effects were similar whether the target and UFF background were simultaneously presented or briefly separated; however, the UFF had no effect when the two were spatially separated. The effects of the UFF background on VEP onset response increased with increasing temporal frequency from 2–8 Hz; offset responses were affected similarly at all temporal frequencies. These effects are similar to those observed in humans and suggest that two spatio-temporally tuned mechanisms contribute to the early VEP response. In the cat, the mechanisms seem to correspond to X and Y cells in the dorsal lateral geniculate nucleus.
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Hogland, John, e David L. R. Affleck. "Mitigating the Impact of Field and Image Registration Errors through Spatial Aggregation". Remote Sensing 11, n. 3 (22 gennaio 2019): 222. http://dx.doi.org/10.3390/rs11030222.
Testo completoAbstract (sommario):
Remotely sensed data are commonly used as predictor variables in spatially explicit models depicting landscape characteristics of interest (response) across broad extents, at relatively fine resolution. To create these models, variables are spatially registered to a known coordinate system and used to link responses with predictor variable values. Inherently, this linking process introduces measurement error into the response and predictors, which in the latter case causes attenuation bias. Through simulations, our findings indicate that the spatial correlation of response and predictor variables and their corresponding spatial registration (co-registration) errors can have a substantial impact on the bias and accuracy of linear models. Additionally, in this study we evaluate spatial aggregation as a mechanism to minimize the impact of co-registration errors, assess the impact of subsampling within the extent of sample units, and provide a technique that can be used to both determine the extent of an observational unit needed to minimize the impact of co-registration and quantify the amount of error potentially introduced into predictive models.
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Neill, W. Trammell, e Abigail L. Kleinsmith. "Spatial negative priming: Location or response?" Attention, Perception, & Psychophysics 78, n. 8 (27 luglio 2016): 2411–19. http://dx.doi.org/10.3758/s13414-016-1176-6.
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Manahilov, V. "Multiphasic Spatial Response to Flickering Stimuli". Perception 26, n. 1_suppl (agosto 1997): 255. http://dx.doi.org/10.1068/v970259.
Testo completoAbstract (sommario):
If it is assumed that the weighting function of early vision can be described by a spatiotemporal Gabor-like function (Manahilov, 1995 Vision Research35 227 – 237), the spatial impulse response to flickering stimuli would consist of more alternating phases than that to a brief stimulus. To test this prediction, the Westheimer paradigm and the brightness matching technique were used. The effect of a flickering inducing disk (temporal frequency 7.7 Hz, duration 195 ms, zero starting phase) of variable radius on the apparent brightness of an incremental test stimulus (1.2 min arc radius, duration 14.25 ms) was measured in foveal photopic vision. The test stimulus was superimposed on the centre of the inducing disk and presented 142 ms after the onset of the inducing stimulus. When the radius of the inducing stimulus was increased, the test brightness was enhanced, reaching a maximum at a radius of 3 min arc, then diminished below the control level at radii of 9 – 11 min arc and was enhanced again at radii of 14 – 17 min arc. This finding differed from the unimodal effect of a brief inducing disk on test brightness and suggested a multiphasic profile of the spatial impulse response to a flickering stimulus. This suggestion was supported by the dependence of the apparent brightness of a test line on the distance between the test and two flanking inducing lines. The temporal conditions were similar to those of the previous experiment. The brightness of the test line was increased above the control level at distances of 0 – 2 min arc, decreased at distances of 3 – 6 min arc and again increased to a smaller extent at distances of 10 – 13 min arc. Brief inducing lines evoked only the initial enhancement of the test-line brightness and its decrease at lateral positions. The data obtained are in line with the predictions of the model of the visual weighting function.
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Zhang, Jiahao, Qianwen Ying e Zhichao Ruan. "Time response of plasmonic spatial differentiators". Optics Letters 44, n. 18 (10 settembre 2019): 4511. http://dx.doi.org/10.1364/ol.44.004511.
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Zembaty, Zbigniew, e Steen Krenk. "Spatial Seismic Excitations and Response Spectra". Journal of Engineering Mechanics 119, n. 12 (dicembre 1993): 2449–60. http://dx.doi.org/10.1061/(asce)0733-9399(1993)119:12(2449).
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Janusson, Eric, Amelia V. Hesketh, Karlee L. Bamford, Katherine Hatlelid, Rehan Higgins e J. Scott McIndoe. "Spatial effects on electrospray ionization response". International Journal of Mass Spectrometry 388 (settembre 2015): 1–8. http://dx.doi.org/10.1016/j.ijms.2015.07.016.
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Neill, W. T., e A. L. Kleinsmith. "Spatial Negative Priming: Location or Response?" Journal of Vision 14, n. 10 (22 agosto 2014): 1032. http://dx.doi.org/10.1167/14.10.1032.
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Sandel, B., L. Arge, B. Dalsgaard, R. G. Davies, K. J. Gaston, W. J. Sutherland e J. C. Svenning. "Response--Global Endemism Needs Spatial Integration". Science 335, n. 6066 (19 gennaio 2012): 285–86. http://dx.doi.org/10.1126/science.335.6066.285-a.
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FRANCESWANG, R. "Action, verbal response and spatial reasoning". Cognition 94, n. 2 (dicembre 2004): 185–92. http://dx.doi.org/10.1016/j.cognition.2004.05.001.
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Levine, Michael W., e Roger P. Zimmerman. "Evidence for local circuits within the receptive fields of retinal ganglion cells in goldfish". Visual Neuroscience 1, n. 4 (luglio 1988): 377–85. http://dx.doi.org/10.1017/s0952523800004144.
Testo completoAbstract (sommario):
AbstractA new form of receptive field map, the response-component map, was developed to identify points within a receptive field that produce similar response patterns. The fields were probed with discretely flashed small spots of light. The magnitudes of the responses to stimulus onset and to stimulus offset elicited at each point were represented on the map by a vector radiating from the position representing the location of that point. Thus, response-component maps preserve the spatial distributions of responsivity and temporal nonlinearities. Points with similar response patterns were identified from a scatterplot in which the response at each spatial position was located in a plane representing the angles of the response-component vectors. Points with similar response characteristics that were also spatially contiguous were considered as a distinct response subregion within the receptive field.Barely 10% of the receptive fields of goldfish ganglion cells mapped with this technique proved as simple as the traditional concentric field described for retinal cells. In at least 17% of the cases, the field showed three concentric rings, with a very small “inner center” within the center of the field. In at least 50% of the cases, response subregions of different type lay side by side, rather than in a concentric configuration. Some subregions could be differentiated by the relative strengths of the responses to onset and offset of the stimulus spot, supporting the hypothesis that a push-pull system generates ganglion cell responses. Subregions were evident in successive mappings of the same cell, demonstrating they are not due to the vagaries of individual responses. They probably represent the spatial domains (or their intersections) of individual interneurons distal to the retinal ganglion cells. It is possible that position within the receptive field may be coded by the temporal pattern of the responses.
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Miyashita, Y., E. T. Rolls, P. M. Cahusac, H. Niki e J. D. Feigenbaum. "Activity of hippocampal formation neurons in the monkey related to a conditional spatial response task". Journal of Neurophysiology 61, n. 3 (1 marzo 1989): 669–78. http://dx.doi.org/10.1152/jn.1989.61.3.669.
Testo completoAbstract (sommario):
To analyze neurophysiologically the functions of the primate hippocampus, the activity of 905 single hippocampal formation neurons was analyzed in two rhesus monkeys performing a conditional spatial response task known to be impaired in monkeys and in man by damage to the hippocampus or fornix. In the task, the monkey learned to make one spatial response, touching a screen three times when he saw one visual stimulus on the video monitor, and a different spatial response, of withdrawing his hand from the screen, when a different visual stimulus was shown. Fourteen percent of the neurons fired differentially to one or the other of the stimulus-spatial response associations. The mean latency of these differential responses was 154 +/- 44 (SD) ms. The firing of these neurons was shown to reflect a combination of the particular stimulus and the particular response associated by learning in the stimulus-response association task and could not be accounted for by the motor requirements of the task, nor wholly the stimulus aspects of the task, as demonstrated by testing their firing in related visual discrimination tasks. Responsive neurons were found throughout the hippocampal formation, but were particularly concentrated in the subicular complex and the CA3 subfield. These results show that single hippocampal neurons respond to combinations of the visual stimuli and the spatial responses with which they must become associated in conditional spatial response tasks and are consistent with the suggestion that part of the mechanism of this learning involves associations between visual stimuli and spatial responses learned by single hippocampal neurons.
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Cooper, Bonnie, Barry B. Lee e Dingcai Cao. "Macaque retinal ganglion cell responses to visual patterns: harmonic composition, noise, and psychophysical detectability". Journal of Neurophysiology 115, n. 6 (1 giugno 2016): 2976–88. http://dx.doi.org/10.1152/jn.00411.2015.
Testo completoAbstract (sommario):
The goal of these experiments was to test how well cell responses to visual patterns can be predicted from the sinewave tuning curve. Magnocellular (MC) and parvocellular (PC) ganglion cell responses to different spatial waveforms (sinewave, squarewave, and ramp waveforms) were measured across a range of spatial frequencies. Sinewave spatial tuning curves were fit with standard Gaussian models. From these fits, waveforms and spatial tuning of a cell's responses to the other waveforms were predicted for different harmonics by scaling in amplitude for the power in the waveform's Fourier expansion series over spatial frequency. Since higher spatial harmonics move at a higher temporal frequency, an additional scaling for each harmonic by the MC (bandpass) or PC (lowpass) temporal response was included, together with response phase. Finally, the model included a rectifying nonlinearity. This provided a largely satisfactory estimation of MC and PC cell responses to complex waveforms. As a consequence of their transient responses, MC responses to complex waveforms were found to have significantly more energy in higher spatial harmonic components than PC responses. Response variance (noise) was also quantified as a function of harmonic component. Noise increased to some degree for the higher harmonics. The data are relevant for psychophysical detection or discrimination of visual patterns, and we discuss the results in this context.
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Frye, J. Michael, e Anthony Q. Martin. "Wideband Extrapolation of Spatial Responses of Resonant Structures Using Early-Time and Low-Frequency Data". Journal of Computational Methods in Physics 2013 (22 ottobre 2013): 1–12. http://dx.doi.org/10.1155/2013/563724.
Testo completoAbstract (sommario):
An efficient procedure is presented to extrapolate a wideband electromagnetic response defined over an arbitrary spatial region using early-time and low-frequency data. The previous procedures presented in the literature are efficient for single-point extrapolation and can readily be applied to spatial regions but are terribly inefficient when a response is desired at many spatial locations. In this work, an optimized algorithm is presented to quickly extrapolate over a large number of spatial locations. The time and frequency behavior of the response is fitted by polynomials and pole terms, and the spatial variation is represented with spatially dependent polynomial coefficients and pole residues. A single set of poles, common to all spatial locations of interest, is shown to sufficiently describe the resonant behavior of response over the entire spatial region. A multisignal formulation of the matrix pencil method is applied to determine poles from early time data. Numerical examples are presented to demonstrate the procedure. Additionally, an automated approach to distinguish physical poles, which correspond to structural resonances, from nonphysical fitting poles is presented. The spatially dependent residues of physical pole terms, referred to here as modal residues, are shown to provide important insight into the resonant behavior of a structure.
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Berwick, J., D. Johnston, M. Jones, J. Martindale, C. Martin, A. J. Kennerley, P. Redgrave e J. E. W. Mayhew. "Fine Detail of Neurovascular Coupling Revealed by Spatiotemporal Analysis of the Hemodynamic Response to Single Whisker Stimulation in Rat Barrel Cortex". Journal of Neurophysiology 99, n. 2 (febbraio 2008): 787–98. http://dx.doi.org/10.1152/jn.00658.2007.
Testo completoAbstract (sommario):
The spatial resolution of hemodynamic-based neuroimaging techniques, including functional magnetic resonance imaging, is limited by the degree to which neurons regulate their blood supply on a fine scale. Here we investigated the spatial detail of neurovascular events with a combination of high spatiotemporal resolution two-dimensional spectroscopic optical imaging, multichannel electrode recordings and cytochrome oxidase histology in the rodent whisker barrel field. After mechanical stimulation of a single whisker, we found two spatially distinct cortical hemodynamic responses: a transient response in the “upstream” branches of surface arteries and a later highly localized increase in blood volume centered on the activated cortical column. Although the spatial representation of this localized response exceeded that of a single “barrel,” the spread of hemodynamic activity accurately reflected the neural response in neighboring columns rather than being due to a passive “overspill.” These data confirm hemodynamics are capable of providing accurate “single-condition” maps of neural activity.
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Chen, Zhongwen, Dongmyung Oh, Kabir H. Biswas, Cheng-Han Yu, Ronen Zaidel-Bar e Jay T. Groves. "Spatially modulated ephrinA1:EphA2 signaling increases local contractility and global focal adhesion dynamics to promote cell motility". Proceedings of the National Academy of Sciences 115, n. 25 (4 giugno 2018): E5696—E5705. http://dx.doi.org/10.1073/pnas.1719961115.
Testo completoAbstract (sommario):
Recent studies have revealed pronounced effects of the spatial distribution of EphA2 receptors on cellular response to receptor activation. However, little is known about molecular mechanisms underlying this spatial sensitivity, in part due to lack of experimental systems. Here, we introduce a hybrid live-cell patterned supported lipid bilayer experimental platform in which the sites of EphA2 activation and integrin adhesion are spatially controlled. Using a series of live-cell imaging and single-molecule tracking experiments, we map the transmission of signals from ephrinA1:EphA2 complexes. Results show that ligand-dependent EphA2 activation induces localized myosin-dependent contractions while simultaneously increasing focal adhesion dynamics throughout the cell. Mechanistically, Src kinase is activated at sites of ephrinA1:EphA2 clustering and subsequently diffuses on the membrane to focal adhesions, where it up-regulates FAK and paxillin tyrosine phosphorylation. EphrinA1:EphA2 signaling triggers multiple cellular responses with differing spatial dependencies to enable a directed migratory response to spatially resolved contact with ephrinA1 ligands.
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Victor, J. D., K. Purpura, E. Katz e B. Mao. "Population encoding of spatial frequency, orientation, and color in macaque V1". Journal of Neurophysiology 72, n. 5 (1 novembre 1994): 2151–66. http://dx.doi.org/10.1152/jn.1994.72.5.2151.
Testo completoAbstract (sommario):
1. We recorded local field potentials in the parafoveal representation in the primary visual cortex of anesthetized and paralyzed macaque monkeys with a multicontact electrode that provided for sampling of neural activity at 16 sites along a vertical penetration. Differential recordings at adjacent contacts were transformed into an estimate of current source density (CSD), to provide a measure of local neural activity. 2. We used m-sequence stimuli to map the region of visual space that provided input to the recording site. The local field potential recorded in macaque V1 has a population receptive field (PRF) size of approximately 2 deg2. 3. We assessed spatial tuning by the responses to two-dimensional Gaussian noise, spatially filtered to retain power only within one octave. Responses to achromatic band-limited noise stimuli revealed a prominent band-pass spatial tuning in the upper layers, but a more low-pass spatial tuning in lower layers. 4. We assessed orientation tuning by the responses to band-limited noise whose spectrum was further restricted to lie within 45 degrees wedges. The local field potential showed evidence of orientation tuning at most sites. Orientation tuning in upper and lower layers was manifest by systematic variations not only in response size but also in response dynamics. 5. We assessed chromatic tuning by the responses to isotropic band-limited noise modulated in a variety of directions in tristimulus space. Some lower-layer locations showed a nulling of response under near-isoluminant conditions. However, response dynamics in upper and lower layers depended not only on luminance contrast, but also on chromatic inputs. 6. Responses to near-isoluminant stimuli and to low-contrast luminance modulation were shifted to lower spatial frequencies. 7. We determined the extent to which various temporal frequencies in the response conveyed information concerning spatial frequency, orientation, and color under the steady-state conditions used in these studies. In each case, information is distributed in the response dynamics across a broad temporal frequency range, beginning at 4 Hz (the lowest frequency used). For spatial frequency the information rate remains significant up to at least 25 Hz. For orientation tuning and chromatic tuning, the information rate is lower overall and remains significant up to 13 Hz. In contrast, for texture discrimination, information is shifted to lower temporal frequencies.
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Engström, David, Martin Persson, Jörgen Bengtsson e Mattias Goksör. "Calibration of spatial light modulators suffering from spatially varying phase response". Optics Express 21, n. 13 (28 giugno 2013): 16086. http://dx.doi.org/10.1364/oe.21.016086.
Testo completo
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Spitzer, H., e S. Hochstein. "A complex-cell receptive-field model". Journal of Neurophysiology 53, n. 5 (1 maggio 1985): 1266–86. http://dx.doi.org/10.1152/jn.1985.53.5.1266.
Testo completoAbstract (sommario):
The time course of the response of a single cortical neuron to counterphase-grating stimulation may vary as a function of stimulation parameters, as shown in the preceding paper (19). The poststimulus-time histograms of the response amplitudes against time are single or double peaked, and where double peaked, the two peaks are of equal or unequal amplitudes. Furthermore, the spatial-phase dependence of cortical complex-cell responses may be a function of spatial frequency, so that the receptive field appears to have linear spatial summation at some spatial frequencies and nonlinear spatial summation at others (19). In the first part of this paper, we analyze a model receptive field that displays this behavior, and in the second part experimental data are presented and analyzed with regard to the model. The model cortical receptive field in its simplest form contains (two rows) of geniculate X-cell-like, DOG (difference-of-Gaussians)-shaped, center-surround antagonistic, circular-input subunits. We propose nonlinear summation between these two subunits, by introducing a half-wave rectification stage before pooling. The model is tested for the responses it predicts for the application of counterphase-grating stimulation. This simple model predicts the appearance of three response forms as a function of counterphase-stimulation parameters. At periodic spatial frequencies the expected-response histogram has a single peak, whose amplitude has a sinusoidal dependence on spatial phase. At spatial frequencies halfway between these, the expected-response histogram has two equal peaks whose amplitudes have a full-wave rectified sinusoidal dependence on spatial phase. At all intermediate spatial frequencies the expected-response histogram has a "mixed" form; the histogram appears sometimes with one peak, sometimes with two equal peaks, and generally with two peaks of unequal amplitude, as a function of spatial phase. Null responses are expected to appear at specific spatial phases only for the periodic spatial frequencies that give "pure" response time courses as in paragraph 5 above, and not in the more common mixed response case of paragraph 6. The analysis procedure described in the preceding paper (19) is used, separating the odd and even Fourier components of the response histograms reflecting the receptive-field intrasubunit linear summation and intersubunit nonlinear summation, respectively. We propose that this model may be used as a working hypothesis for the analysis of these aspects of the various cortical receptive-field types. Experimental data are described and discussed in terms of the model.(ABSTRACT TRUNCATED AT 400 WORDS)
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Iacoboni, M., R. P. Woods e J. C. Mazziotta. "Brain-behavior relationships: evidence from practice effects in spatial stimulus-response compatibility". Journal of Neurophysiology 76, n. 1 (1 luglio 1996): 321–31. http://dx.doi.org/10.1152/jn.1996.76.1.321.
Testo completoAbstract (sommario):
1. We measured relative cerebral blood flow (rCBF) changes with positron emission tomography and H(2) 15O in six normal subjects repeatedly performing a spatial stimulus-response compatibility task. Subjects had two motor response conditions. They were instructed to respond with the left hand to a left visual field light stimulus and with the right hand to a right visual field light stimulus (compatible condition), and with the right hand to a left visual field light stimulus and with the left hand to a right visual field light stimulus (incompatible condition). Six rCBF measurements per condition were performed in each subject. 2. Reaction times were faster (P < 0.0005) in the compatible (287 ms) than the incompatible (339 ms) condition (spatial stimulus-response compatibility effect). A bilateral increase (P < 0.05) in rCBF in the superior parietal lobule of the two hemispheres was observed during the incompatible condition when compared with the compatible one. No rCBF decreases were observed. Reaction times correlated (P < 0.0001) with the rCBF in the two activated superior parietal lobule areas. 3. Reaction times decreased with practice according to a linear trend (P < 0.05). Practice-related linear rCBF increases (P < 0.05) were observed in the dorsolateral prefrontal, premotor, and primary motor cortex of the left hemisphere. No significant rCBF decreases were observed. 4. Practice did not affect the spatial stimulus-response compatibility effect. A parallel shortening of reaction times was observed in both compatible and incompatible conditions, in both left and right hand responses, and in both left and right visual fields. Accordingly, when rCBF was analyzed, the spatial stimulus-response compatibility by practice interaction did not show any significant activated area. 5. These findings suggest that the two activated areas in the left and right superior parietal lobules subserve the mapping of the visual stimulus spatial attributes onto the motor response spatial attributes and that the rCBF increases in the incompatible response condition represent the more complex computational remapping required when stimuli and response do not match spatially. 6. The dorsolateral prefrontal, premotor, and motor rCBF linear increases in the left hemisphere seem to reflect the effect of practice on cortical processes common to both compatible and incompatible response conditions. These cortical processes presumably strengthen the links between stimuli and responses under different stimulus-response compatibility conditions. The lateralization of the rCBF increases suggests a left hemisphere superiority in these processes.
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Victor, Jonathan D., e Keith P. Purpura. "Spatial Phase and the Temporal Structure of the Response to Gratings in V1". Journal of Neurophysiology 80, n. 2 (1 agosto 1998): 554–71. http://dx.doi.org/10.1152/jn.1998.80.2.554.
Testo completoAbstract (sommario):
Victor, Jonathan D. and Keith P. Purpura. Spatial phase and the temporal structure of the response to gratings in V1. J. Neurophysiol. 80: 554–571, 1998. We recorded single-unit activity of 25 units in the parafoveal representation of macaque V1 to transient appearance of sinusoidal gratings. Gratings were systematically varied in spatial phase and in one or two of the following: contrast, spatial frequency, and orientation. Individual responses were compared based on spike counts, and also according to metrics sensitive to spike timing. For each metric, the extent of stimulus-dependent clustering of individual responses was assessed via the transmitted information, H. In nearly all data sets, stimulus-dependent clustering was maximal for metrics sensitive to the temporal pattern of spikes, typically with a precision of 25–50 ms. To focus on the interaction of spatial phase with other stimulus attributes, each data set was analyzed in two ways. In the “pooled phases” approach, the phase of the stimulus was ignored in the assessment of clustering, to yield an index H pooled. In the “individual phases” approach, clustering was calculated separately for each spatial phase and then averaged across spatial phases to yield an index H indiv. H pooled expresses the extent to which a spike train represents contrast, spatial frequency, or orientation in a manner which is not confounded by spatial phase (phase-independent representation), whereas H indiv expresses the extent to which a spike train represents one of these attributes, provided spatial phase is fixed (phase-dependent representation). Here, representation means that a stimulus attribute has a reproducible and systematic influence on individual responses, not a neural mechanism for decoding this influence. During the initial 100 ms of the response, contrast was represented in a phase-dependent manner by simple cells but primarily in a phase-independent manner by complex cells. As the response evolved, simple cell responses acquired phase-independent contrast information, whereas complex cells acquired phase-dependent contrast information. Simple cells represented orientation and spatial frequency in a primarily phase-dependent manner, but also they contained some phase-independent information in their initial response segment. Complex cells showed primarily phase-independent representation of orientation but primarily phase-dependent representation of spatial frequency. Joint representation of two attributes (contrast and spatial frequency, contrast and orientation, spatial frequency and orientation) was primarily phase dependent for simple cells, and primarily phase independent for complex cells. In simple and complex cells, the variability in the number of spikes elicited on each response was substantially greater than the expectations of a Poisson process. Although some of this variation could be attributed to the dependence of the response on the spatial phase of the grating, variability was still markedly greater than Poisson when the contribution of spatial phase to response variance was removed.
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Tanabe, Seiji, e Bruce G. Cumming. "Delayed suppression shapes disparity selective responses in monkey V1". Journal of Neurophysiology 111, n. 9 (1 maggio 2014): 1759–69. http://dx.doi.org/10.1152/jn.00426.2013.
Testo completoAbstract (sommario):
The stereo correspondence problem poses a challenge to visual neurons because localized receptive fields potentially cause false responses. Neurons in the primary visual cortex (V1) partially resolve this problem by combining excitatory and suppressive responses to encode binocular disparity. We explored the time course of this combination in awake, monkey V1 neurons using subspace mapping of receptive fields. The stimulus was a binocular noise pattern constructed from discrete spatial frequency components. We forward correlated the firing of the V1 neuron with the occurrence of binocular presentations of each spatial frequency component. The forward correlation yielded a complete set of response time courses to every combination of spatial frequency and interocular phase difference. Some combinations produced suppressive responses. Typically, if an interocular phase difference for a given spatial frequency produced strong excitation, we saw suppression in response to the opposite interocular phase difference at lower spatial frequencies. The suppression was delayed relative to the excitation, with a median difference in latency of 7 ms. We found that the suppressive mechanism explains a well-known mismatch of monocular and binocular signals. The suppressive components increased power at low spatial frequencies in disparity tuning, whereas they reduced the monocular response to low spatial frequencies. This long-recognized mismatch of binocular and monocular signals reflects a suppressive mechanism that helps reduce the response to false matches.
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Porciatti, V., R. Alesci e P. Bagnoli. "Evoked responses to sinusoidal gratings in the pigeon optic tectum". Visual Neuroscience 2, n. 2 (febbraio 1989): 137–45. http://dx.doi.org/10.1017/s0952523800011998.
Testo completoAbstract (sommario):
AbstractTectal evoked potentials (TEPs) in response to sinusoidal gratings of different contrast, spatial and temporal frequency have been recorded from the tectal surface of the pigeon. Responses have been digitally filtered in order to isolate transient oscillatory (fast) potentials (50–150 Hz), transient slow potentials (1–50 Hz), and the steady-state second-harmonic component (16.6 Hz). Transient slow potentials, as well as the steady-state second-harmonic component, are band-pass spatially tuned with a maximum at 0.5 cycles/deg and attenuation at higher and lower spatial frequencies. The high spatial frequency cutoff is 4–5 cycles/deg. Both transient slow potentials and the steady-state second-harmonic component increase in amplitude as a function of log contrast and saturate at about 20% contrast. The contrast sensitivity, as determined by extrapolating TEP amplitude to 0 V is 0.1–0.2%. These characteristics of spatial-frequency selectivity and contrast sensitivity are similar to those reported for single tectal cells. Unlike slow potentials, oscillatory potentials are not band-pass spatially tuned. In addition, their contrast response function does not saturate at moderate contrast. These differences suggest that tectal evoked slow and fast potentials reflect the activity of different neuronal mechanisms.
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Xu, Ru, Yan Li, Kaiyu Guan, Lei Zhao, Bin Peng, Chiyuan Miao e Bojie Fu. "Divergent responses of maize yield to precipitation in the United States". Environmental Research Letters 17, n. 1 (30 dicembre 2021): 014016. http://dx.doi.org/10.1088/1748-9326/ac3cee.
Testo completoAbstract (sommario):
Abstract How maize yield response to precipitation varies across a large spatial scale is unclear compared with the well-understood temperature response, even though precipitation change is more erratic with greater spatial heterogeneity. This study provides a spatial-explicit quantification of maize yield response to precipitation in the contiguous United States and investigates how precipitation response is altered by natural and human factors using statistical and crop model data. We find the precipitation responses are highly heterogeneous with inverted-U (40.3%) being the leading response type, followed by unresponsive (30.39%), and linear increase (28.6%). The optimal precipitation threshold derived from inverted-U response exhibits considerable spatial variations, which is higher under wetter, hotter, and well-drainage conditions but lower under drier, cooler, and poor-drainage conditions. Irrigation alters precipitation response by making yield either unresponsive to precipitation or having lower optimal thresholds than rainfed conditions. We further find that the observed precipitation responses of maize yield are misrepresented in crop models, with a too high percentage of increase type (59.0% versus 29.6%) and an overestimation in optimal precipitation threshold by ∼90 mm. These two factors explain about 30% and 85% of the inter-model yield overestimation biases under extreme rainfall conditions. Our study highlights the large spatial heterogeneity and the key role of human management in the precipitation responses of maize yield, which need to be better characterized in crop modeling and food security assessment under climate change.
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Nattkemper, Dieter, e Wolfgang Prinz. "Impact of task demands on spatial stimulis-response compatibility". Zeitschrift für Psychologie / Journal of Psychology 209, n. 3 (luglio 2001): 205–26. http://dx.doi.org/10.1026//0044-3409.209.3.205.
Testo completoAbstract (sommario):
Summary. Two experiments explored the impact of task demands on spatial stimulus-response compatibility. Task demands were manipulated to either emphasize stationary or dynamic aspects (positions or movements) in both stimuli and responses. For matched task configurations where the same features are emphasized for stimuli and responses results indicate a strong impact of task requirements on the relative magnitude of position-based vs. direction-based compatibility effects. For unmatched tasks where different features are emphasized in stimuli and responses results suggest that information about movement direction is recoded into position information, specifying the direction of stimulus or response movements in terms of their respective endpoint positions. Further, in some task configurations, an unexpected inverted direction-based compatibility effect was observed which can be explained in terms of referential coding. Referential coding acts to specify the position of a fixed stimulus relative to a moving stimulus, presumably based on an attentional spotlight mechanism.
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-, Yuni Andriyani Safitri, Pamuti, Risky Nuri Amelia e Ramdani Salam. "Kemampuan Berpikir Kritis Mahasiswa Pendidikan Geografi Pada Implementasi Case Based Learning dalam Mata Kuliah Geomorfologi Dasar". Jurnal Spatial Wahana Komunikasi dan Informasi Geografi 23, n. 1 (7 marzo 2023): 1–9. http://dx.doi.org/10.21009/spatial.231.6.
Testo completoAbstract (sommario):
Changes in the paradigm of student center-based learning are starting to take place in Indonesian universities. This is stated and emphasized in the main university performance indicators (IKU7), namely collaborative and participatory classes. At the implementation stage, various types of learning models were developed, but explicitly CBL and PjBL were used as the main raw models. The purpose of this study was to determine the effect of the application of the Case Based Learning (CBL) model on improving students' critical thinking skills. The subjects in this study amounted to 25 people with the type of quantitative research one group pretest and posttest design. The results show that the CBL model is quite effective in improving students' critical thinking skills through calculating the percentage n-gain score of 56.24%. This finding is reinforced by the high positive response of students to the learning model through perception networking through research questionnaires.
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George, Justin, e Todd Sandler. "EU Demand for Defense, 1990–2019: A Strategic Spatial Approach". Games 12, n. 1 (1 febbraio 2021): 13. http://dx.doi.org/10.3390/g12010013.
Testo completoAbstract (sommario):
For 1990–2019, this study presents two-step GMM estimates of EU members’ demands for defense spending based on alternative spatial-weight matrices. In particular, EU spatial connectivity is tied to EU membership status, members’ contiguity, contiguity and power projection, inverse distance, and arms trade. At a Nash equilibrium, our EU demand equations are derived explicitly from a spatially based game-theoretical model of alliances. Myriad spatial linkages among EU members provide a robust free-riding finding, which differs from the spatial and non-spatial literature on EU defense spending. Even though the EU applies common trade policies and allows for unrestricted labor movement among members, members’ defense responses adhered to those of a defense alliance. Moreover, EU defense spending exhibits positive responses to GDP and transnational terrorist attacks, and a negative response to population. During the sample period, EU members did not view Russia as a military threat.
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Bilotta, J., e I. Abramov. "Spatiospectral properties of goldfish retinal ganglion cells". Journal of Neurophysiology 62, n. 5 (1 novembre 1989): 1140–48. http://dx.doi.org/10.1152/jn.1989.62.5.1140.
Testo completoAbstract (sommario):
1. Responses of single ganglion cells from isolated goldfish retinas were recorded during presentation of various spatial and spectral stimuli. Each cell was classified along several spatial [spatial summation class, spatial contrast sensitivity function (CSF), and response to contrast] and spectral (Red-ON, Red-OFF or Red-ON/OFF, and spectral opponency/nonopponency) dimensions. 2. Linearity of spatial summation was determined from responses to contrast-reversal sinusoidal gratings positioned at various locations across the receptive field of the cell. CSFs were derived from responses to sinusoidal gratings of various spatial frequencies and contrasts, drifting across the cell's receptive field at a rate of 4 Hz. Response to contrast was determined from responses to variations in contrast of a sinusoidal grating of optimal spatial frequency. Spectral classifications were based on responses to monochromatic stimuli presented separately to the center and surround portions of the receptive field. 3. Linearity of spatial summation (X-, Y-, and W-like) was independent of the cell's spectral properties; for example, an X-like cell could be classified as either a Red-ON, Red-OFF, or Red-ON/OFF center cell and as spectrally opponent or nonopponent. 4. There were differences in response to contrast across spectral categories. Red-OFF center cells were very sensitive to contrast compared with Red-ON center cells. Spectrally nonopponent cells were more responsive to contrast than spectrally opponent cells. 5. There were dramatic differences across the spectral categories in relative sensitivity to low spatial frequency stimuli; however, the spatial resolution (i.e., sensitivity to high spatial frequencies) of each spectral classification appeared to be similar.(ABSTRACT TRUNCATED AT 250 WORDS)
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Schäfer, Sarah, e Christian Frings. "Different effects of spatial separation in action and perception". Psychonomic Bulletin & Review 28, n. 3 (26 gennaio 2021): 845–52. http://dx.doi.org/10.3758/s13423-020-01867-9.
Testo completoAbstract (sommario):
AbstractSpatial distance of response keys has been shown to have an effect on nonspatial tasks in that performance improved if the spatial distance increased. Comparably, spatial distance of stimulus features has been shown to have a performance-improving effect in a (partly) spatial task. Here, we combined these two findings in the same task to test for the commonality of the effect of stimulus distance and the effect of response distance. Thus, we varied spatial distance in exactly the same fashion either between stimuli or between responses in a standard Eriksen flanker task. The results show that spatial distance only affected the processing of stimulus features, while it had no effect on the processing of response features. Regarding the idea of common coding of action and perception (Prinz, 1990), stimulus and response processing should be influenced by spatial distance in the same way so that our data might suggest a boundary for the idea of common coding.
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Wenstrup, J. J., Z. M. Fuzessery e G. D. Pollak. "Binaural neurons in the mustache bat's inferior colliculus. II. Determinants of spatial responses among 60-kHz EI units". Journal of Neurophysiology 60, n. 4 (1 ottobre 1988): 1384–404. http://dx.doi.org/10.1152/jn.1988.60.4.1384.
Testo completoAbstract (sommario):
1. The responses to closed-field and free-field sound stimuli were obtained from EI neurons in the 60-kHz isofrequency representation of the mustache bat's inferior colliculus. The goals of the study were 1) to examine how binaural interactions and the directional properties of the ear shape the spatial response of 60-kHz EI neurons and 2) to examine features of the spatial responses of these isofrequency neurons which may encode the location of a sound. 2. The free-field response of monaural neurons was used to describe directional effects of the head and external ears at 60 kHz. Monaural neurons were most sensitive to sounds originating 26 degrees into the contralateral field, with sharply reduced sensitivity in the ipsilateral field and the lateral extreme of the contralateral field. The interaural intensity difference (IID), computed by assuming that the ears had mirror-image directional sensitivities, was greatest for sounds between 26 and 52 degrees off the vertical midline, where IIDs typically ranged from 20 to 30 dB. These values agree well with previous measures of the directional sensitivity of the ear obtained from cochlear microphonic recordings. 3. The response of a monaural unit to closed-field stimulation was used to predict its response to free-field stimulation. This prediction agreed closely with the observed free-field response, indicating that the monaural unit's free-field response could be explained by the directional sensitivity of the contralateral ear and the unit's response as a function of contralateral sound intensity. 4. EI neurons differed in basic features of their binaural response properties, as described in a companion paper. To examine how these features of binaural inhibition shaped spatial responses, we obtained responses to free-field sounds among neurons whose binaural properties had been thoroughly characterized. We then compared the spatial response to a prediction based upon the directional properties of the ear and the sensitivity of the EI neurons to IIDs and intensity. The close agreement between the observed and predicted spatial responses in 11 of 12 EI units indicated that the spatial responses were determined largely by sensitivity to IIDs and intensity and by the directional properties of the ear. 5. EI neurons in our sample were most sensitive, and responded best, to sounds originating 26-39 degrees into the contralateral field. These spatial response features were independent of the binaural properties of EI neurons. Instead, they depended upon the directional properties of the ears at 60 kHz.(ABSTRACT TRUNCATED AT 400 WORDS)
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Thissen, Alica, Marco Koch, Nicolas Becker e Frank M. Spinath. "Construct Your Own Response". European Journal of Psychological Assessment 34, n. 5 (settembre 2018): 304–11. http://dx.doi.org/10.1027/1015-5759/a000342.
Testo completoAbstract (sommario):
Abstract. The cube construction task represents a novel format in the assessment of spatial ability through mental cube rotation tasks. Instead of selecting the correct answer from several response options, testees construct their own response in a computerized test environment. The format has several advantages: It is no longer possible to guess the correct response or to compare the reference cube to the response options, resulting in a higher demand for spatial ability. Moreover, it is possible to create items with a particularly high difficulty which are needed for the assessment of intellectual giftedness. In the present study, we developed 28 items and presented them to a sample of 130 university students. Test results showed that the items possess a very high statistical difficulty. Furthermore, the item set yielded a very high internal consistency. The results of an exploratory factor analysis as well as of a multidimensional IRT analysis indicated that a two-factor solution (“spatial relations” vs. “spatial visualization”) is plausible. Response time had a negligible influence on accuracy. Perspectives on further research concerning the cube construction task and possibilities for practical applications are being discussed.
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Pantazopoulou, Chrysoula K., Franca J. Bongers, Jesse J. Küpers, Emilie Reinen, Debatosh Das, Jochem B. Evers, Niels P. R. Anten e Ronald Pierik. "Neighbor detection at the leaf tip adaptively regulates upward leaf movement through spatial auxin dynamics". Proceedings of the National Academy of Sciences 114, n. 28 (26 giugno 2017): 7450–55. http://dx.doi.org/10.1073/pnas.1702275114.
Testo completoAbstract (sommario):
Vegetation stands have a heterogeneous distribution of light quality, including the red/far-red light ratio (R/FR) that informs plants about proximity of neighbors. Adequate responses to changes in R/FR are important for competitive success. How the detection and response to R/FR are spatially linked and how this spatial coordination between detection and response affects plant performance remains unresolved. We show in Arabidopsis thaliana and Brassica nigra that localized FR enrichment at the lamina tip induces upward leaf movement (hyponasty) from the petiole base. Using a combination of organ-level transcriptome analysis, molecular reporters, and physiology, we show that PIF-dependent spatial auxin dynamics are key to this remote response to localized FR enrichment. Using computational 3D modeling, we show that remote signaling of R/FR for hyponasty has an adaptive advantage over local signaling in the petiole, because it optimizes the timing of leaf movement in response to neighbors and prevents hyponasty caused by self-shading.
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Rouhbakhsh, Nematollah, John Mahdi, Jacob Hwo, Baran Nobel e Fati Mousave. "Human Frequency Following Response Correlates of Spatial Release From Masking". Journal of Speech, Language, and Hearing Research 62, n. 11 (22 novembre 2019): 4165–78. http://dx.doi.org/10.1044/2019_jslhr-h-18-0353.
Testo completoAbstract (sommario):
Purpose Speech recognition in complex listening environments is enhanced by the extent of spatial separation between the speech source and background competing sources, an effect known as spatial release from masking (SRM). The aim of this study was to investigate whether the phase-locked neural activity in the central auditory pathways, reflected in the frequency following response (FFR), exhibits SRM. Method Eighteen normal-hearing adults (8 men and 10 women, ranging in age from 20 to 42 years) with no known neurological disorders participated in this study. FFRs were recorded from the participants in response to a target vowel /u/ presented with spatially colocated and separated competing talkers at 3 ranges of signal-to-noise ratios (SNRs), with median SNRs of −5.4, 0.5, and 6.8 dB and for different attentional conditions (attention and no attention). Results Amplitude of the FFR at the fundamental frequency was significantly larger in the spatially separated condition as compared to the colocated condition for only the lowest (< −2.4 dB SNR) of the 3 SNR ranges tested. A significant effect of attention was found when subjects were actively focusing on the target stimuli. No significant interaction effects were found between spatial separation and attention. Conclusions The enhanced representation of the target stimulus in the separated condition suggests that the temporal pattern of phase-locked brainstem neural activity generating the FFR may contain information relevant to the binaural processes underlying SRM but only in challenging listening environments. Attention may modulate FFR fundamental frequency amplitude but does not seem to modulate spatial processing at the level of generating the FFR. Supplemental Material https://doi.org/10.23641/asha.9992597
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Dittrich, Kerstin, Thomas Dolk, Annelie Rothe-Wulf, Karl Christoph Klauer e Wolfgang Prinz. "Keys and seats: Spatial response coding underlying the joint spatial compatibility effect". Attention, Perception, & Psychophysics 75, n. 8 (30 luglio 2013): 1725–36. http://dx.doi.org/10.3758/s13414-013-0524-z.
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Huybers, Kathleen, e Gerard H. Roe. "Spatial Patterns of Glaciers in Response to Spatial Patterns in Regional Climate". Journal of Climate 22, n. 17 (1 settembre 2009): 4606–20. http://dx.doi.org/10.1175/2009jcli2857.1.
Testo completoAbstract (sommario):
Abstract Glaciers are direct recorders of climate history and have come to be regarded as emblematic of climate change. They respond to variations in both accumulation and ablation, which can have separate atmospheric controls, leading to some ambiguity in interpreting the causes of glacier changes. Both climate change and climate variability have characteristic spatial patterns and time scales. The focus of this study is the regional-scale response of glaciers to natural patterns of climate variability. Using the Pacific Northwest of North America as the setting, the authors employ a simple linear glacier model to study how the combination of patterns of melt-season temperature and patterns of annual accumulation produce patterns of glacier length variations. Regional-scale spatial correlations in glacier length variations reflect three factors: the spatial correlations in precipitation and melt-season temperature, the geometry of a glacier and how it determines the relative importance of temperature and precipitation, and the climatic setting of the glaciers (i.e., maritime or continental). With the self-consistent framework developed here, the authors are able to evaluate the relative importance of these three factors. The results also highlight that, in order to understand the natural variability of glaciers, it is critically important to know the small-scale patterns of climate in mountainous terrain. The method can be applied to any area containing mountain glaciers and provides a baseline expectation for natural glacier variation against which the effects of climate changes can be evaluated.