Magnitude Of Cross-correlation Research Articles

Interplay between hippocampal TACR3 and systemic testosterone in regulating anxiety-associated synaptic plasticity.

Tachykinin receptor 3 (TACR3) is a member of the tachykinin receptor family and falls within the rhodopsin subfamily. As a G protein-coupled receptor, it responds to neurokinin B (NKB), its high-affinity ligand. Dysfunctional TACR3 has been associated with pubertal failure and anxiety, yet the mechanisms underlying this remain unclear. Hence, we have investigated the relationship between TACR3 expression, anxiety, sex hormones, and synaptic plasticity in a rat model, which indicated that severe anxiety is linked to dampened TACR3 expression in the ventral hippocampus. TACR3 expression in female rats fluctuates during the estrous cycle, reflecting sensitivity to sex hormones. Indeed, in males, sexual development is associated with a substantial increase in hippocampal TACR3 expression, coinciding with elevated serum testosterone and a significant reduction in anxiety. TACR3 is predominantly expressed in the cell membrane, including the presynaptic compartment, and its modulation significantly influences synaptic activity. Inhibition of TACR3 activity provokes hyperactivation of CaMKII and enhanced AMPA receptor phosphorylation, associated with an increase in spine density. Using a multielectrode array, stronger cross-correlation of firing was evident among neurons following TACR3 inhibition, indicating enhanced connectivity. Deficient TACR3 activity in rats led to lower serum testosterone levels, as well as increased spine density and impaired long-term potentiation (LTP) in the dentate gyrus. Remarkably, aberrant expression of functional TACR3 in spines results in spine shrinkage and pruning, while expression of defective TACR3 increases spine density, size, and the magnitude of cross-correlation. The firing pattern in response to LTP induction was inadequate in neurons expressing defective TACR3, which could be rectified by treatment with testosterone. In conclusion, our study provides valuable insights into the intricate interplay between TACR3, sex hormones, anxiety, and synaptic plasticity. These findings highlight potential targets for therapeutic interventions to alleviate anxiety in individuals with TACR3 dysfunction and the implications of TACR3 in anxiety-related neural changes provide an avenue for future research in the field.

Effects of spatial characteristics of footsteps sounds and non-acoustic factors on annoyance in lightweight timber buildings

This study investigates the effect of spatial characteristics of footsteps sound from upstairs in wooden residential buildings together with the influence of non-acoustic factors on annoyance ratings. Footsteps sound were recorded in the laboratory, where a typical lightweight timber joists floor is located between the source and receiving room. Two adults walked on the floor over three different paths (figure-of-eight, straight, and walking on the spot) at two different paces (very slow and normal). The spatial features of the recordings were quantified in terms of the magnitude of interaural cross-correlation (IACC) function. A total of 46 participants were recruited and they assessed their subjective annoyance after exposure to noise under laboratory conditions. During the laboratory experiments, 360-degree pictures of a living room during daytime or night-time were presented via a Head-Mounted Display (HMD). In addition, the participants were asked to answer questions concerning noise sensitivity, chronotype, and attitude towards neighbours. Results highlighted that IACC had a significant effect on annoyance, showing an increase in annoyance with increasing IACC. Footsteps at a very slow pace were more annoying than those at a normal pace. It was also found that annoyance ratings with a presentation of the living room during daytime were greater than those with a presence of the night-time living room. Furthermore, noise sensitivity, circadian rhythm, and attitude towards neighbours of participants were significant in moderating annoyance ratings.

Financial Return Distributions: Past, Present, and COVID-19.

We analyze the price return distributions of currency exchange rates, cryptocurrencies, and contracts for differences (CFDs) representing stock indices, stock shares, and commodities. Based on recent data from the years 2017–2020, we model tails of the return distributions at different time scales by using power-law, stretched exponential, and q-Gaussian functions. We focus on the fitted function parameters and how they change over the years by comparing our results with those from earlier studies and find that, on the time horizons of up to a few minutes, the so-called “inverse-cubic power-law” still constitutes an appropriate global reference. However, we no longer observe the hypothesized universal constant acceleration of the market time flow that was manifested before in an ever faster convergence of empirical return distributions towards the normal distribution. Our results do not exclude such a scenario but, rather, suggest that some other short-term processes related to a current market situation alter market dynamics and may mask this scenario. Real market dynamics is associated with a continuous alternation of different regimes with different statistical properties. An example is the COVID-19 pandemic outburst, which had an enormous yet short-time impact on financial markets. We also point out that two factors—speed of the market time flow and the asset cross-correlation magnitude—while related (the larger the speed, the larger the cross-correlations on a given time scale), act in opposite directions with regard to the return distribution tails, which can affect the expected distribution convergence to the normal distribution.

A Generalized Construction of Multiple Complete Complementary Codes and Asymptotically Optimal Aperiodic Quasi-Complementary Sequence Sets

In recent years, complete complementary codes (CCCs) and quasi-complementary sequence sets (QCSSs) have found many important applications in multi-carrier code-division multiple-access (MC-CDMA) systems for their good correlation properties. In this paper, we propose a generic construction of multiple sets of CCCs over $\mathbb {Z}_{N}$ , consisting of sequences of length $N$ , where $N\geq 3$ is an arbitrary odd integer. Interestingly, the maximum inter-set aperiodic cross-correlation magnitude of the proposed CCCs is upper bounded by $N$ . It turns out that the combination of the generated CCCs results in a new set of sequences to obtain asymptotically optimal and near-optimal aperiodic QCSSs. The proposed construction includes a recent optimal construction of QCSSs with prime length as a special case and leads to asymptotically optimal QCSSs with new flexible parameters.

Multiscale analysis of the spatial variability of heavy metals and organic matter in soils and groundwater across Spain

During the last years there has been an increasing interest in assessing health risks caused by exposure to contaminants found in soil, air, and water, like heavy metals or emerging contaminants. This work presents a study on the spatial patterns and interaction effects among relevant heavy metals (Sb, As and Pb) that may occur together in different minerals. Total organic carbon (TOC) have been analyzed too because it is an essential component in the regulatory mechanisms that control the amount of metal in soils. Even more, exposure to these elements is associated with a number of diseases and environmental problems. These metals can have both natural and anthropogenic origins. A key component of any exposure study is a reliable model of the spatial distribution the elements studied. A geostatistical analysis have been performed in order to show that selected metals are auto-correlated and cross-correlated and type and magnitude of such cross-correlation varies depending on the spatial scale under consideration. After identifying general trends, we analyzed the residues left after subtracting the trend from the raw variables. Three scales of variability were identified (compounds or factors) with scales of 5, 35 and 135 km. The first factor (F1) basically identifies anomalies of natural origin but, in some places, of anthropogenics origin as well. The other two are related to geology (F2 and F3) although F3 represents more clearly geochemical background related to large lithological groups. Likewise, mapping of two major structures indicates that significant faults have influence on the distribution of the studied elements. Finally, influence of soil and lithology on groundwater by means of contingency analysis was assessed.

Assessing spatially dependent errors in radar rainfall estimates for rainfall-runoff simulation

Weather radar been widely employed to measure precipitation and to predict flood risks. However, it is still not considered accurate enough because of radar errors. Most previous studies have focused primarily on removing errors from the radar data. Therefore, in the current study, we examined the effects of radar rainfall errors on rainfall-runoff simulation using the spatial error model (SEM). SEM was used to synthetically generate random or cross-correlated errors. A number of events were generated to investigate the effect of spatially dependent errors in radar rainfall estimates on runoff simulation. For runoff simulation, the Nam River basin in South Korea was used with the distributed rainfall-runoff model, Vflo™. The results indicated that spatially dependent errors caused much higher variations in peak discharge than independent random errors. To further investigate the effect of the magnitude of cross-correlation among radar errors, different magnitudes of spatial cross-correlations were employed during the rainfall-runoff simulation. The results demonstrated that a stronger correlation led to a higher variation in peak discharge up to the observed correlation structure while a correlation stronger than the observed case resulted in lower variability in peak discharge. We concluded that the error structure in radar rainfall estimates significantly affects predictions of the runoff peak. Therefore, efforts to not only remove the radar rainfall errors, but to also weaken the cross-correlation structure of the errors need to be taken to forecast flood events accurately.

Influence of cross correlation between soil parameters on probability of failure of simple cohesive and c-ϕ slopes

This paper focuses on the calculation of probability of failure of simple unreinforced slopes and the influence of the magnitude of cross correlation between soil parameters on numerical outcomes. A general closed-form solution for cohesive slopes with cross correlation between cohesion and unit weight was investigated and results compared with cases without cross correlation. Negative cross correlations between cohesion and friction angle and positive cross correlations between cohesion and unit weight, and friction angle and unit weight were considered in the current study. The factors of safety and probabilities of failure for the slopes with uncorrelated soil properties were obtained using probabilistic slope stability design charts previously reported by the writers. Results for cohesive soil slopes and positive cross correlation between cohesion and unit weight are shown to decrease probability of failure. Probability of failure also decreased for increasing negative cross correlation between cohesion and friction angle, and increasing positive correlation between cohesion and unit weight, and friction angle and unit weight. Probabilistic slope stability design charts presented by the writers in an earlier publication are extended to include cohesive-frictional (c-[Formula: see text]) soil slopes with and without cross correlation between soil input parameters. An important outcome of the work presented here is that cross correlation between random values of soil properties can reduce the probability of failure for simple slope cases. Hence, previous probabilistic design charts by the writers for simple soil slopes with uncorrelated soil properties are conservative (safe) for design. This study also provides one explanation why slope stability analyses using uncorrelated soil properties can predict unreasonably high probabilities of failure when conventional estimates of factor of safety suggest a stable slope.

Crosstalk opposing view: Fear of falling does not influence vestibular-evoked balance responses.

Crosstalk opposing view: Fear of falling does not influence vestibular-evoked balance responses.

Respiratory and cardiovascular modulations in patients with spinal cord injury

Evaluation of autonomic cardiovascular deficits is clinically important to investigate the extent of impairment after spinal cord injury (SCI), and is based on recordings of blood pressure (BP) and heart rate (HR) in response to various conditions including orthostatic stress. Spectral power analyses of BP and HR oscillations during these tests can be used to evaluate sympathetic (0.04‐0.15Hz) and parasympathetic (0.15‐0.4Hz) regulations of cardiovascular function. These tests don't include the monitoring of respiration with the assumption that amplitude and frequency of these oscillations are regular, and located within the parasympathetic frequency range. However, respiratory insufficiency is common in SCI individuals due to paralysis, muscle weakness and/or spastic contractions of the muscles involved in respiration. We hypothesized that oscillatory respiratory patterns observed in SCI patients have a different autonomic effects compared to those in non‐injured. The aim was to investigate in what extent respiratory oscillatory patterns can affect autonomic cardiovascular responses in individuals with different neurological levels and severity of SCI. BP, HR and respiratory kinematics were recorded continuously at rest and in response to orthostatic stress in SCI and non‐injured subjects. SCI individuals demonstrated irregular breathing patterns that resulted in two main peak frequencies located both below and above 0.15 Hz. Magnitude of cross correlation between respiratory and both HR and BP significantly increased in frequencies below 0.15Hz and decreased above 0.15 Hz compared to non‐injured group. These results indicate that respiratory related oscillations in BP and HR can be augmented due to both pulmonary and autonomic nervous system dysfunction after SCI.

Balanced Quaternary Sequences Pairs of Odd Period With (Almost) Optimal Autocorrelation and Cross-Correlation

In this letter, two lower bounds on the maximum cross-correlation magnitude of balanced quaternary sequence pairs with (almost) optimal autocorrelation are presented. The maximum cross-correlation magnitude of a balanced quaternary sequence pair of period N with the maximum out-of-phase autocorrelation magnitude √5, where N = 4f + 1 is a prime and f is an odd integer, is shown to be √N, achieving one of the new lower bounds.

Properties and Crosscorrelation of Decimated Sidelnikov Sequences

SUMMARY In this paper, we show that if the d-decimation of a (q−1)ary Sidelnikov sequence of period q − 1 = p m − 1i s thed-multiple of the same Sidelnikov sequence, then d must be a power of a prime p .A lso, we calculate the crosscorrelation magnitude between some constant multiples of d -a ndd � -decimations of a Sidelnikov sequence of period q − 1t o be upper bounded by (d + d � − 1) √ q + 3.

Subband Extraction Strategies in Ship Detection With the Subaperture Cross-Correlation Magnitude

The subaperture cross-correlation magnitude (SCM) has previously been proposed as a statistic that improves the contrast between small ship targets and the surrounding sea in synthetic-aperture-radar images. This preprocessing technique utilizes the fast decorrelation of open-water surface ripples on the scale of the SAR wavelength relative to coherent targets such as a ship. However, optimization of the bandwidth splitting in the subband extraction has not received any attention. The aim of this letter is twofold: 1) to describe the technical details of the algorithm, including modifications that are necessary to allow overlapping subapertures; and 2) to study the effect of splitting the bandwidth into two azimuth subapertures with respect to varying bandwidths and subaperture overlap. The impact on the SCM is investigated in terms of measures of speckle reduction and target-to-clutter contrast. Experiments are performed on real single-look complex SAR data containing repeated acquisitions of a vessel in open sea. The results indicate that the subband extraction strategy has a clear impact on performance.

Corrections to the Magnitude of Cross-Correlation Functions for Dispersion of Solar Acoustic Waves

The cross-correlation function is a useful tool in helioseismology. The magnitude of the cross-correlation function has been used to represent the power of wave packets. Dispersion causes a decrease in amplitude and an increase in width of wave packets. This leads to a decrease in magnitude and an increase in width of cross-correlation functions. The effect of dispersion on the magnitude of cross-correlation functions needs to be adequately corrected for in order to use the magnitude of cross-correlation functions to represent the power of wave packets. In this study, we investigate how the magnitude of cross-correlation functions changes with the number of skips owing to dispersion and the method to correct it. Our study, using simulated and observational data, indicates that the correction should be three dimensional instead of the one-dimensional correction adopted in previous studies. Using the three-dimensional correction, the measured dissipation rate in the quiet Sun is smaller than the value of previous studies.

Subjective evaluation of heavy-weight floor impact sounds in relation to spatial characteristics

This study investigated the effect of a spatial factor, the magnitude of interaural cross-correlation (IACC) function, on subjective responses to heavy-weight floor impact sounds. Heavy-weight impact sounds were generated by a heavy/soft impact source (impact ball) in real apartments, so that impact sound pressure levels (SPLs) (L(Amax)) and IACC could be analyzed. Just noticeable differences (JNDs) of impact SPL and IACC were investigated through the use of impact ball sounds. JNDs were determined by the criteria of 75% correct answers by participants, and it was found that JNDs of impact SPL and IACC were around 1.5 dB and 0.12-0.13, respectively. In addition, the annoyance caused by an impact ball was evaluated by changes in these two parameters. The results show that annoyance increased with increasing impact SPL and with decreasing IACC; the contributions of the two parameters to the scale value of annoyance were 79.3% and 20.4%, respectively. This indicates that the effects of IACC should be considered for the evaluation of annoyance, and the subjective response to impact ball sounds can be improved by controlling IACC, as well as impact SPL.

Minimum Cross Correlation Spreading Codes

Multiple access interference (MAI) appears in Code Division Multiple Access (CDMA) systems when the communication channel is a multi-path channel and the spreading codes are not orthogonal. Orthogonality between spreading codes cannot be maintained at the CDMA receiver because the codes may be asynchronous due to channel delay and multi-path spread. The receiver cannot perfectly separate the different signals of the multiple access users, and the resultant MAI limits the capacity of CDMA systems. MAI is a function of the cross correlation property between used spreading codes. In this paper we focus on the cross correlation of the spreading codes, we propose a method to find spreading codes with minimum magnitude of cross correlation. Employing these codes will reduce the resultant MAI in the CDMA system; hence it will increase the system capacity. A great enhancement is shown by comparing found minimum cross correlation spreading codes (MCCSC) with Hadamard and Gold codes.

Robust Frame Synchronization for Chinese DTTB System

Digital terrestrial multimedia/television broadcasting (DTMB), which is the recently released Chinese digital television terrestrial broadcasting (DTTB) standard, uses guard intervals padded with known pseudo-noise (PN) sequences for multi-carrier or single-carrier block transmission. Well designed synchronization algorithms are a prerequisite for achieving high-quality multimedia transmission. In this paper, a novel frame synchronization technique, which is robust to carrier frequency offset (CFO), is proposed for DTMB systems. This technique is derived through segmenting the local PN sequence into M contiguous blocks and performing multiple cross-correlations with the received signal. The metric for peak detection is defined as the non-coherent summation of the M cross-correlation magnitude outputs. Moreover, a low-complexity frame synchronizer based on segment-based full correlation for PN420 mode in DTMB system is proposed. It is shown through computer simulation that the proposed techniques generally outperform the conventional ones when CFO occurs, over both AWGN and frequency-selective fading channels. For a DTMB system using PN420 mode, the maximal allowed CFO to keep system still working normally of our proposed schemes are more than 3 times larger than that of the conventional method.

Blood pressure regulation in neurally intact human vs. acutely injured paraplegic and tetraplegic patients during passive tilt

We investigated autonomic control of cardiovascular function in able-bodied (AB), paraplegic (PARA), and tetraplegic (TETRA) subjects in response to head-up tilt following spinal cord injury. We evaluated spectral power of blood pressure (BP), baroreflex sensitivity (BRS), baroreflex effectiveness index (BEI), occurrence of systolic blood pressure (SBP) ramps, baroreflex sequences, and cross-correlation of SBP with heart rate (HR) in low (0.04-0.15 Hz)- and high (0.15-0.4 Hz)-frequency regions. During tilt, AB and PARA effectively regulated BP and HR, but TETRA did not. The numbers of SBP ramps and percentages of heartbeats involved in SBP ramps and baroreflex sequences increased in AB, were unchanged in PARA, and declined in TETRA. BRS was lowest in PARA and declined with tilt in all groups. BEI was greatest in AB and declined with tilt in all groups. Low-frequency power of BP and the peak of the SBP/HR cross-correlation magnitude were greatest in AB, increased during tilt in AB, remained unchanged in PARA, and declined in TETRA. The peak cross-correlation magnitude in HF decreased with tilt in all groups. Our data indicate that spinal cord injury results in decreased stimulation of arterial baroreceptors and less engagement of feedback control as demonstrated by lower 1) spectral power of BP, 2) number (and percentages) of SBP ramps and barosequences, 3) cross-correlation magnitude of SBP/HR, 4) BEI, and 5) changes in delay between SBP/HR. Diminished vasomotion and impaired baroreflex regulation may be major contributors to decreased orthostatic tolerance following injury.

Analysis of masking effects on speech intelligibility with respect to moving sound stimulus

The purpose of this study is to compare the disturbed degree of speech by an immovable noise source and an apparent moving one (AMN). In the study of the sound localization, we found that source-directional sensitivity (SDS) well associates with the magnitude of interaural cross correlation (IACC). Ando et al. [Y. Ando, S. H. Kang, and H. Nagamatsu, J. Acoust. Soc. Jpn. (E) 8, 183–190 (1987)] reported that potential correlation between left and right inferior colliculus at auditory path in the brain is in harmony with the correlation function of amplitude input into two ear-canal entrances. We assume that the degree of disturbance under the apparent moving noisy source is probably different from that being installed in front of us within a constant distance in a free field (no reflection). Then, we found there is a different influence on speech intelligibility between a moving and a fixed source generated by 1/3-octave narrow-band noise with the center frequency 2 kHz. However, the reasons for the moving speed and the masking effects on speech intelligibility were uncertain.

Generalized GMW Quadriphase Sequences Satisfying the Welch Bound with Equality

This paper gives new families of quadriphase sequences obtained from large linear complexity sequences over Z4 by making use of generalized permutation monomials over Galois rings. The construction of these sequences can be seen as a generalization of the binary GMW sequence construction and hence they are referred to as GGMW sequences over Z4. The GGMW families satisfy the Welch bound on inner products with equality and it is shown that the root mean square of all the crosscorrelations and out-of-phase autocorrelations (θrms), is approximately equal to the quantity \(\); L being the period of the sequences. However, θmax, the maximum magnitude of periodic crosscorrelation and out-of-phase autocorrelation, deviates from the optimal value of \(\). Computer results suggest that the number of crosscorrelation values which deviate from the optimal value of \(\) is small. The weight structure of these sequences is the same as those of m-sequences over Z4. The linear complexity (LC) of the sequences is computed using a generalized Blahuts theorem on the LC of sequences over Z4.

Analyses of cortical continuous brain waves in relation to subjective preference of physical environments

Analyses of cortical continuous brain waves in relation to subjective preference of physical environments