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Accurate estimation of the absorption of chromophoric dissolved organic matter (CDOM) in ultraviolet (UV) wavelength range is crucial for understanding photochemical and biochemical processes in the global ocean. Here, we propose a novel UV absorption extrapolation (UVAE) algorithm. It extrapolates the absorption coefficients (a g (λ) where λ is the wavelength in nm) of CDOM in the UV wavelength range from ocean color data in the visible wavelength range observed by satellite remote sensing. The extrapolation is based on the assumption that three characteristic Gaussian bands describe the CDOM UV–visible absorption spectra (275–443 nm). The UVAE algorithm retrieves the a g (275), a g (295), a g (330), and a g (380) using the characteristics of the spectral slope (S) of the absorbance spectra of CDOM at specific wavelength intervals, namely 275–295, 295–330, 330–380, and 380–443 nm. With the UVAE algorithm, the spatial variability of CDOM spectral features can be captured on a global scale using data from the Moderate-resolution Imaging Spectroradiometer (MODIS) Aqua mission. The retrieved a g (275), a g (295), a g (330), and a g (380) values match well with in-situ observed values, with mean absolute percent differences (MAPDs) of 19.2 %, 26.1 %, 36.9 %, and 46.6 %, respectively. The performance of the UVAE algorithm demonstrates a significant improvement compared to that of existing algorithms, especially for a g (λ) at lower wavelengths. [ABSTRACT FROM AUTHOR]

Recent studies suggest that the EEG aperiodic exponent (often represented as a slope in log–log space) is sensitive to individual differences in momentary cognitive skills such as selective attention and information processing speed. However, findings are mixed, and most of the studies have focused on just a narrow range of cognitive domains. This study used an archival dataset to help clarify associations between resting aperiodic features and broad domains of cognitive ability, which vary in their demands on momentary processing. Undergraduates (N = 166) of age 18–52 years completed a resting EEG session as well as a standardized, individually administered assessment of cognitive ability that included measures of processing speed, working memory, and higher‐order visuospatial and verbal skills. A subsample (n = 110) also completed a computerized reaction time task with three difficulty levels. Data reduction analyses revealed strong correlations between the aperiodic offset and slope across electrodes, and a single component accounted for ~60% of variance in slopes across the scalp, in both eyes‐closed and eyes‐open conditions. Structural equation models did not support relations between the slope and specific domains tapping momentary processes. However, secondary analyses indicated that the eyes‐open slope was related to higher overall performance, as represented by a single general ability factor. A latent reaction time variable was significantly inversely related to both eyes‐closed and eyes‐open resting exponents, such that faster reaction times were associated with steeper slopes. These findings support and help clarify the relation of the resting EEG exponent to individual differences in cognitive skills. This study is among the first to examine associations between the EEG aperiodic slope and cognitive performance as assessed by both validated clinical assessments and laboratory tasks in the same cohort. Results replicated prior findings that higher resting slopes are linked to faster reaction times. This association did not extend to individually‐administered tasks of clerical speed, working memory, or higher order visuospatial or verbal skills; however, the slope was related to a single general ability factor in the eyes‐open resting condition. [ABSTRACT FROM AUTHOR]

Study region: Laptev Sea Study focus: The absorption slopes of colored dissolved organic matter (CDOM) in the spectral range of 275–295 nm (S275–295) is a reliable parameter of the source and transformation of CDOM and dissolved organic carbon (DOC) in the estuarine environment. Studying S275–295 in coastal areas can provide important information about CDOM and DOC. This study proposed a new multilayer backpropagation neural network (MBPNN) based on the relationship between S275–295 and aCDOM(443) (absorption of CDOM at 443 nm) as a customization function to invert S275–295. The model accurately estimated S275–295 with a MAPE and RMSE of 6.12 % and 0.0012 nm−1, respectively, and revealed the spatiotemporal distribution of S275–295 in the Laptev Sea between 2002 and 2022 (July to September). The effects of influencing factors on temporal and spatial variations of S275–295 were analyzed. New hydrological insights for the region: The MBPNN model with a customization function has good performance to invert S275–295 in Laptev Sea. The S275–295 in the Laptev Sea ranged from 0.014 to 0.022 nm−1. S275–295 increased gradually from coastal waters to the open sea. Inter-annual S275–295 fluctuated, but no significant trend was observed during the study period (2002–2022). S275–295 was negatively correlated with river discharge (r=-0.41), permafrost thaw depth (r=-0.42), ice extent (r=-0.55) and Normalized Difference Vegetation Index (r=-0.46) but positively correlated with salinity (r=0.86) and wind speed (r=0.46).

Auditory processing and the complexity of neural activity can both indicate residual consciousness levels and differentiate states of arousal. However, how measures of neural signal complexity manifest in neural activity following environmental stimulation and, more generally, how the electrophysiological characteristics of auditory responses change in states of reduced consciousness remain under‐explored. Here, we tested the hypothesis that measures of neural complexity and the spectral slope would discriminate stages of sleep and wakefulness not only in baseline electroencephalography (EEG) activity but also in EEG signals following auditory stimulation. High‐density EEG was recorded in 21 participants to determine the spatial relationship between these measures and between EEG recorded pre‐ and post‐auditory stimulation. Results showed that the complexity and the spectral slope in the 2–20 Hz range discriminated between sleep stages and had a high correlation in sleep. In wakefulness, complexity was strongly correlated to the 20–40 Hz spectral slope. Auditory stimulation resulted in reduced complexity in sleep compared to the pre‐stimulation EEG activity and modulated the spectral slope in wakefulness. These findings confirm our hypothesis that electrophysiological markers of arousal are sensitive to sleep/wake states in EEG activity during baseline and following auditory stimulation. Our results have direct applications to studies using auditory stimulation to probe neural functions in states of reduced consciousness. [ABSTRACT FROM AUTHOR]

A method for studying properties of the Earth's surface tremor, measured by means of GPS, is proposed. The following tremor characteristics are considered: the entropy of wavelet coefficients, the Donoho–Johnston wavelet index, and two estimates of the spectral slope. The anomalous areas of tremor are determined by estimating the probability densities of extreme values of the studied properties. The criteria for abnormal tremor behavior are based on the proximity to, or the difference between, tremor properties and white noise. The greatest deviation from the properties of white noise is characterized by entropy minima and spectral slope and DJ index maxima. This behavior of the tremor is called "active". The "passive" tremor behavior is characterized by the maximum proximity to the properties of white noise. The principal components approach provides weighted averaged density maps of these two variants of extreme distributions of parameters in a moving time window of 3 years. Singular points are the points of maximum average densities. The method is applied to the analysis of daily time series from a GPS network in California during the period 2009–2022. Singular points of tremor form well-defined clusters were found. The passive tremor could be caused by the activation of movement in fragments of the San Andreas fault. [ABSTRACT FROM AUTHOR]

Using the non-affected leg as stable frame of reference for the affected leg in gait assessment in knee osteoarthritis (KO) fails due to compensatory mechanisms. Assessing the cyclical movements of the upper extremities in a frequency-controlled repetitive punching task may provide an alternative frame of reference in gait assessment in patients with KO. Eleven participants with unilateral KO and eleven healthy controls were asked to perform treadmill walking and repetitive punching. The KO group showed more predictable (p = 0.020) and less automatized (p = 0.007) movement behavior than controls during treadmill walking. During repetitive punching, the KO group showed a similar degree of predictability (p = 0.784) but relative more automatized movement behavior (p = 0.013). Thus, the predictability of the movement behavior of the upper extremities during repetitive punching seems unaffected by KO and could provide an alternative frame of reference in gait assessment in patients with KO. [ABSTRACT FROM AUTHOR]

Colored dissolved organic matter (CDOM) is an important optically active substance in marine environment. Its biochemical conservatism makes it an important indicator to offshore pollution process. Monitoring the content, composition, and diffusion process of CDOM is a good approach to analyze the terrestrial input, optical properties, and ecological environment of offshore areas. The spatiotemporal characteristics of CDOM around the Leizhou Peninsula were analyzed based on field observation data collected in the autumn 2020 and spring 2021, and an empirical inversion model of the ag(355) (absorption coefficient at 355 nm) and spectral slope (Sg) (g stands for gelbstoff/gilvin, which is called CDOM) based on Sentinel-3A ocean and land color instrument (OLCI) images was constructed. The results show (1) the order of average ag(355) value around the Leizhou Peninsula was east coast (0.503/m)>Qiongzhou Strait (0.502/m)>west coast (0.365/m); (2) the best band combinations of CDOM inversion in spring and autumn were (B4+B11)/B3 and (B7–B1)/B6 (B stands for the band of spectral images), and the final inversion results are close to the measured results, indicating that the model has good accuracy; (3) the Sg value of the CDOM absorption spectrum was fitted to the hyperbolic-exponential model. The fitting accuracy of the model was higher than those of the exponential model and the hyperbolic model, and the best Sg inversion model was constructed by selecting Sg(275–295) and Sg(250–295) in spring and autumn; (4) the spatial distributions of ag(355) and Sg were inverted, and CDOM in the waters around the Leizhou Peninsula originated from terrestrial organic matter carried by coastal aquaculture zones and runoff in the northeast Zhanjiang and the northern Beibu Gulf. [ABSTRACT FROM AUTHOR]

• Electroencephalography tracks perioperative performance changes in visual working memory and verbal learning. • Enhanced beta oscillations after anesthesia impair differential processing in working memory resulting in more liberal decisions. • A decline in task-related upregulation of aperiodic brain activity after anesthesia is associated with impaired verbal learning. Anesthesia and surgery are associated with cognitive impairment, particularly memory deficits. So far, electroencephalography markers of perioperative memory function remain scarce. We included male patients >60 years scheduled for prostatectomy under general anesthesia. We obtained neuropsychological assessments and a visual match-to-sample working memory task with simultaneous 62-channel scalp electroencephalography 1 day before and 2 to 3 days after surgery. Twenty-six patients completed both pre- and postoperative sessions. Compared with preoperative performance, verbal learning deteriorated after anesthesia (California Verbal Learning Test total recall; t 25 = −3.25, p = 0.015, d = −0.902), while visual working memory performance showed a dissociation between match and mismatch accuracy (match*session F 1,25 = 3.866, p = 0.060). Better verbal learning was associated with an increase of aperiodic brain activity (total recall r = 0.66, p = 0.029, learning slope r = 0.66, p = 0.015), whereas visual working memory accuracy was tracked by oscillatory theta/alpha (7 – 9 Hz), low beta (14 – 18 Hz) and high beta/gamma (34 – 38 Hz) activity (matches: p < 0.001, mismatches: p = 0.022). Oscillatory and aperiodic brain activity in scalp electroencephalography track distinct features of perioperative memory function. Aperiodic activity provides a potential electroencephalographic biomarker to identify patients at risk for postoperative cognitive impairments. [ABSTRACT FROM AUTHOR]

Increased spontaneous gamma (30–100 Hz) activity (SGA) has been reported in the auditory cortex in schizophrenia. This phenomenon has been correlated with psychotic symptoms such as auditory hallucinations and could reflect the dysfunction of NMDA receptors on parvalbumin-expressing inhibitory interneurons. Previous findings are from time-averaged spectra, so it is unknown whether increased spontaneous gamma occurs at a constant level, or rather in bursts. To better understand the dynamical nature of spontaneous gamma activity in schizophrenia, here we examined the contribution of gamma bursting and the slope of the EEG spectrum to this phenomenon. The main results from this data set were previously reported. Participants were 24 healthy control participants (HC) and 24 matched participants with schizophrenia (SZ). The data were from EEG recordings during auditory steady-state stimulation, which were localized to bilateral pairs of dipoles in auditory cortex. Time-frequency analysis was performed using Morlet wavelets. Oscillation bursts in the gamma range were defined as periods during which power exceeded 2 standard deviations above the trial-wide average value for at least one cycle. We extracted the burst parameters power, count, and area, as well as non-burst trial power and spectral slope. Gamma burst power and non-burst trial power were greater in SZ than HC, but burst count and area did not differ. Spectral slope was less negative in SZ than HC. Regression modeling found that gamma burst power alone best predicted SGA for both HC and SZ (> = 90% of variance), while spectral slope made a small contribution and non-burst trial power did not influence SGA. Increased SGA in the auditory cortex in schizophrenia is accounted for by increased power within gamma bursts, rather than a tonic increase in gamma-range activity, or a shift in spectral slope. Further research will be necessary to determine if these measures reflect different network mechanisms. We propose that increased gamma burst power is the main component of increased SGA in SZ and could reflect abnormally increased plasticity in cortical circuits due to enhanced plasticity of synapses on parvalbumin-expressing inhibitory interneurons. Thus, increased gamma burst power may be involved in producing psychotic symptoms and cognitive dysfunction. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is widely used in pipeline transportation owing to its excellent corrosion resistance, good stability, and ease of processing. As organic polymer materials, PE pipes inevitably undergo different degrees of aging during long-term use. In this study, terahertz time-domain spectroscopy was used to study the spectral characteristics of PE pipes with different degrees of photothermal aging, and the variation in the absorption coefficient with aging time was obtained. The absorption coefficient spectrum was extracted using uninformative variable elimination (UVE), successive projections algorithm (SPA), competitive adaptive reweighted sampling (CARS), and random frog RF spectral screening algorithms, and the spectral slope characteristics of the aging-sensitive band were selected as the evaluation indices of the degree of PE aging. Based on this, a partial least squares aging characterization model was established to predict white PE80, white PE100 and black PE100 pipes with different aging degrees. The results showed that the prediction accuracy of the absorption coefficient spectral slope feature prediction model for the aging degree of different types of pipes was greater than 93.16% and the verification set error was within 13.5 h. [ABSTRACT FROM AUTHOR]

Chromophoric dissolved organic matter (CDOM) is the main sunlight absorber in surface waters and a very important photosensitiser towards the generation of photochemically produced reactive intermediates (PPRIs), which take part in pollutant degradation. The absorption spectrum of CDOM (ACDOM(λ), unitless) can be described by an exponential function that decays with increasing wavelength: ACDOM(λ) = 100 d DOC Ao e− Sλ, where d [m] is water depth, DOC [mgC L−1] is dissolved organic carbon, Ao [L mgC−1 cm−1] is a pre-exponential factor, and S [nm−1] is the spectral slope. Sunlight absorption by CDOM is higher when Ao and DOC are higher and S is lower, and vice versa. By the use of models, here we investigate the impact of changes in CDOM spectral parameters (Ao and S) on the steady-state concentrations of three PPRIs: the hydroxyl radical (•OH), the carbonate radical (CO3•−), and CDOM excited triplet states (3CDOM*). A first finding is that variations in both Ao and S have impacts comparable to DOC variations on the photochemistry of CDOM, when reasonable parameter values are considered. Therefore, natural variability of the spectral parameters or their modifications cannot be neglected. In the natural environment, spectral parameters could, for instance, change because of photobleaching (prolonged exposure of CDOM to sunlight, which decreases Ao and increases S) or of the complex and still poorly predictable effects of climate change. A second finding is that, while the steady-state [3CDOM*] would increase with increasing ACDOM (increasing Ao, decreasing S), the effect of spectral parameters on [•OH] and [CO3•−] depends on the relative roles of CDOM vs. NO3− and NO2− as photochemical •OH sources. [ABSTRACT FROM AUTHOR]

Increased spontaneous gamma (30–100 Hz) activity (SGA) has been reported in the auditory cortex in schizophrenia. This phenomenon has been correlated with psychotic symptoms such as auditory hallucinations and could reflect the dysfunction of NMDA receptors on parvalbumin-expressing inhibitory interneurons. Previous findings are from time-averaged spectra, so it is unknown whether increased spontaneous gamma occurs at a constant level, or rather in bursts. To better understand the dynamical nature of spontaneous gamma activity in schizophrenia, here we examined the contribution of gamma bursting and the slope of the EEG spectrum to this phenomenon. The main results from this data set were previously reported. Participants were 24 healthy control participants (HC) and 24 matched participants with schizophrenia (SZ). The data were from EEG recordings during auditory steady-state stimulation, which were localized to bilateral pairs of dipoles in auditory cortex. Time-frequency analysis was performed using Morlet wavelets. Oscillation bursts in the gamma range were defined as periods during which power exceeded 2 standard deviations above the trial-wide average value for at least one cycle. We extracted the burst parameters power, count, and area, as well as non-burst trial power and spectral slope. Gamma burst power and non-burst trial power were greater in SZ than HC, but burst count and area did not differ. Spectral slope was less negative in SZ than HC. Regression modeling found that gamma burst power alone best predicted SGA for both HC and SZ (> = 90% of variance), while spectral slope made a small contribution and non-burst trial power did not influence SGA. Increased SGA in the auditory cortex in schizophrenia is accounted for by increased power within gamma bursts, rather than a tonic increase in gamma-range activity, or a shift in spectral slope. Further research will be necessary to determine if these measures reflect different network mechanisms. We propose that increased gamma burst power is the main component of increased SGA in SZ and could reflect abnormally increased plasticity in cortical circuits due to enhanced plasticity of synapses on parvalbumin-expressing inhibitory interneurons. Thus, increased gamma burst power may be involved in producing psychotic symptoms and cognitive dysfunction.

While there is a significant body of research on the dynamics of chromophoric dissolved organic matter (CDOM) in coastal and offshore waters, our understanding of CDOM dynamics in tropical inland water bodies remains limited. To bridge this knowledge gap, a monthly in-situ investigation was carried out at 33 stations along a monsoon driven lagoon, Chilika, on the southeast coast of India for one year i.e., from July 2018 to June 2019. CDOM absorption at 440 nm [aCDOM(440)] data were analyzed as a proxy for CDOM concentration which varied between a range of 0.04–65.14 m−1 with an average value of 2.77 ± 5.23 m−1. A gradient in aCDOM(440) was observed from the river discharge dominated shallower northern sector (4.91 ± 8.32) m−1 to the more isolated and less fresh water influenced deeper southern sector (1.21 ± 1.55) m−1. Spectral slope (S), spectral slope ratio (S R), and molecular weight proxy (M) were computed to understand the possible source and fate of CDOM in the lagoon. The average spectral slope of S 280–500 and S 350–500 vary between 0.002 and 0.096 nm−1 and 0.001–0.095 nm−1, respectively. The (S R) and (M) values ranged between of 0.01–6.81 and 0.31–52.28. It was observed that large-sized, high molecular weight CDOM from terrestrial origin was prevalent during monsoon with lower (S 280–500), (S R), and (M)values. In contrast, lower molecular weight CDOM fractions were prevalent during pre- and post-monsoon which were mainly of autochthonous origin with higher (S 350–500), (S R), and (M) values. Our findings indicate significant spatio-temporal variations of CDOM in Chilika Lagoon, influenced by the monsoon-driven influx of freshwater and the mixing of fresh and marine water. In-situ changes in CDOM are likely shaped by microbial breakdown and photodegradation. [Display omitted] • Monthly CDOM study in Chilika Lagoon from July 2018 to June 2019. • CDOM concentration varied widely, averaging 2.77 ± 5.23 m-1. • North sector had higher CDOM, south sector had lower. • Monsoon brought large, heavy CDOM; other seasons had lighter forms. • Spatial and temporal CDOM variations driven by monsoon and water mixing. [ABSTRACT FROM AUTHOR]

A method for studying properties of the Earth’s surface tremor, measured by means of GPS, is proposed. The following tremor characteristics are considered: the entropy of wavelet coefficients, the Donoho–Johnston wavelet index, and two estimates of the spectral slope. The anomalous areas of tremor are determined by estimating the probability densities of extreme values of the studied properties. The criteria for abnormal tremor behavior are based on the proximity to, or the difference between, tremor properties and white noise. The greatest deviation from the properties of white noise is characterized by entropy minima and spectral slope and DJ index maxima. This behavior of the tremor is called “active”. The “passive” tremor behavior is characterized by the maximum proximity to the properties of white noise. The principal components approach provides weighted averaged density maps of these two variants of extreme distributions of parameters in a moving time window of 3 years. Singular points are the points of maximum average densities. The method is applied to the analysis of daily time series from a GPS network in California during the period 2009–2022. Singular points of tremor form well-defined clusters were found. The passive tremor could be caused by the activation of movement in fragments of the San Andreas fault.

Power spectra of sleep electroencephalograms (EEG) comprise two main components: a decaying power-law corresponding to the aperiodic neural background activity, and spectral peaks present due to neural oscillations. "Traditional" band-based spectral methods ignore this fundamental structure of the EEG spectra and thus are susceptible to misrepresenting the underlying phenomena. A fitting method that attempts to separate and parameterize the aperiodic and periodic spectral components called "fitting oscillations and one over f" (FOOOF) was applied to a set of annotated whole-night sleep EEG recordings of 251 subjects from a wide age range (4-69 years). Most of the extracted parameters exhibited sleep stage sensitivity; significant main effects and interactions of sleep stage, age, sex, and brain region were found. The spectral slope (describing the steepness of the aperiodic component) showed especially large and consistent variability between sleep stages (and lowvariability between subjects), making it a candidate indicator of sleep states. The limitations and arisen problems of the FOOOF method are also discussed, possible solutions for some of them are suggested. [ABSTRACT FROM AUTHOR]

Power spectra of sleep electroencephalograms (EEG) comprise two main components: a decaying power-law corresponding to the aperiodic neural background activity, and spectral peaks present due to neural oscillations. “Traditional” band-based spectral methods ignore this fundamental structure of the EEG spectra and thus are susceptible to misrepresenting the underlying phenomena. A fitting method that attempts to separate and parameterize the aperiodic and periodic spectral components called “fitting oscillations and one over f” (FOOOF) was applied to a set of annotated whole-night sleep EEG recordings of 251 subjects from a wide age range (4–69 years). Most of the extracted parameters exhibited sleep stage sensitivity; significant main effects and interactions of sleep stage, age, sex, and brain region were found. The spectral slope (describing the steepness of the aperiodic component) showed especially large and consistent variability between sleep stages (and low variability between subjects), making it a candidate indicator of sleep states. The limitations and arisen problems of the FOOOF method are also discussed, possible solutions for some of them are suggested.

This study investigates the tropospheric and lower stratospheric 3D wind frequency spectra at Andøya, Norway (69.30°N and 16.04°E) during the years 2017–2020 obtained with the Middle Atmosphere Alomar Radar System. We produce power spectral density S(f) in a broad frequency range (3.5 days−1 > f > 1h−1). We categorize the spectra into different ranges: two frequency ranges (lower and higher than (13 hr)−1 according to the local inertial period of 13 hr), four altitude ranges (lower troposphere, middle troposphere, tropopause region, and lower stratosphere), and four seasons (spring, summer, autumn, and winter). We approximate the power law S(f) ∝ fβ through a least‐square regression. Our results indicate that (a) the spectra of the horizontal winds follow a power law with slopes of about β = −5/3 and −2 at the high and low frequency, respectively, (b) the slopes get steeper around the tropopause and seasonally during the summer (which we report for the first time), and (c) the slope β in the vertical wind is shallow 0 > β > −1, which flattens with altitude. Key Points: Frequency spectra of the horizontal winds in the troposphere and lower stratosphere exhibit power laws with slopes of about −2 and −5/3The horizontal wind slopes steepen in altitude around the tropopause and during summer (particularly at the frequency higher than (13 hr)−1)The power law spectral slopes in the vertical wind are shallower than −1 and flatten with altitude [ABSTRACT FROM AUTHOR]

Spectral analysis of terrain height variance is conducive to quantitatively study the terrain characteristics and grid-size selection for mesoscale models. Improved topographic resolutions can lead to the variations of terrain characteristics and the appropriate grid size for a fixed analyzed area. Spectral methods of one-dimensional weighted average and arithmetic mean were used to investigate the specific impact on the distribution of terrain spectra and grid-size selection for mesoscale models of the landslide-prone areas in western Sichuan. The results indicate that the maximum spectral energy (the variance of the terrain height series) of 30″ resolution (R1) is larger than that of 90 m resolution (R2), indicating a gentler undulation of terrain for R2. The spectral curve of R2 almost overlaps with that of R1 because the difference in topographic resolution does not change the dominant distribution of the topography. Their differing spectral energies at longer wavelengths are related to the majority of grid points of R2 distributed at shorter wavelength bands. A least squares fit in the form of S = a λ b was used to estimate the decreasing trend of the spectral distribution. The difference in spectral slope between R1 and R2 is mainly caused by the spectral energy of R2 at shorter wavelengths. The exponent b is connected with grid-size selection for mesoscale models. A universal horizontal grid size of 2.5 km for R1 and 1.9 km for R2 are required to resolve 95% of the terrain height variance for a mesoscale model application without a subgrid-scale parameterization. The simulation tests show that the improved topographic resolution appears to perform better in reproducing precipitation, which is probably related to the finer details of the terrain recognized by the model. [ABSTRACT FROM AUTHOR]

Dopaminergic medication for Parkinson's disease (PD) modulates neuronal oscillations and functional connectivity (FC) across the basal ganglia-thalamic-cortical circuit. However, the non-oscillatory component of the neuronal activity, potentially indicating a state of excitation/inhibition balance, has not yet been investigated and previous studies have shown inconsistent changes of cortico-cortical connectivity as a response to dopaminergic medication. To further elucidate changes of regional non-oscillatory component of the neuronal power spectra, FC, and to determine which aspects of network organization obtained with graph theory respond to dopaminergic medication, we analyzed a resting-state electroencephalography (EEG) dataset including 15 PD patients during OFF and ON medication conditions. We found that the spectral slope, typically used to quantify the broadband non-oscillatory component of power spectra, steepened particularly in the left central region in the ON compared to OFF condition. In addition, using lagged coherence as a FC measure, we found that the FC in the beta frequency range between centro-parietal and frontal regions was enhanced in the ON compared to the OFF condition. After applying graph theory analysis, we observed that at the lower level of topology the node degree was increased, particularly in the centro-parietal area. Yet, results showed no significant difference in global topological organization between the two conditions: either in global efficiency or clustering coefficient for measuring global and local integration, respectively. Interestingly, we found a close association between local/global spectral slope and functional network global efficiency in the OFF condition, suggesting a crucial role of local non-oscillatory dynamics in forming the functional global integration which characterizes PD. These results provide further evidence and a more complete picture for the engagement of multiple cortical regions at various levels in response to dopaminergic medication in PD. [ABSTRACT FROM AUTHOR]

Dopaminergic medication for Parkinson’s disease (PD) modulates neuronal oscillations and functional connectivity (FC) across the basal ganglia-thalamic-cortical circuit. However, the non-oscillatory component of the neuronal activity, potentially indicating a state of excitation/inhibition balance, has not yet been investigated and previous studies have shown inconsistent changes of cortico-cortical connectivity as a response to dopaminergic medication. To further elucidate changes of regional non-oscillatory component of the neuronal power spectra, FC, and to determine which aspects of network organization obtained with graph theory respond to dopaminergic medication, we analyzed a resting-state electroencephalography (EEG) dataset including 15 PD patients during OFF and ON medication conditions. We found that the spectral slope, typically used to quantify the broadband non-oscillatory component of power spectra, steepened particularly in the left central region in the ON compared to OFF condition. In addition, using lagged coherence as a FC measure, we found that the FC in the beta frequency range between centro-parietal and frontal regions was enhanced in the ON compared to the OFF condition. After applying graph theory analysis, we observed that at the lower level of topology the node degree was increased, particularly in the centro-parietal area. Yet, results showed no significant difference in global topological organization between the two conditions: either in global efficiency or clustering coefficient for measuring global and local integration, respectively. Interestingly, we found a close association between local/global spectral slope and functional network global efficiency in the OFF condition, suggesting a crucial role of local non-oscillatory dynamics in forming the functional global integration which characterizes PD. These results provide further evidence and a more complete picture for the engagement of multiple cortical regions at various levels in response to dopaminergic medication in PD.

In multi-talker listening environments, the culmination of different voice streams may lead to the distortion of each source's individual message, causing deficits in comprehension. Voice characteristics, such as pitch and timbre, are major dimensions of auditory perception and play a vital role in grouping and segregating incoming sounds based on their acoustic properties. The current study investigated how pitch and timbre cues (determined by fundamental frequency, notated as F0, and spectral slope, respectively) can affect perceptual integration and segregation of complex-tone sequences within an auditory streaming paradigm. Twenty normal-hearing listeners participated in a traditional auditory streaming experiment using two alternating sequences of harmonic tone complexes A and B with manipulating F0 and spectral slope. Grouping ranges, the F0/spectral slope ranges over which auditory grouping occurs, were measured with various F0/spectral slope differences between tones A and B. Results demonstrated that the grouping ranges were maximized in the absence of the F0/spectral slope differences between tones A and B and decreased by 2 times as their differences increased to ±1-semitone F0 and ±1-dB/octave spectral slope. In other words, increased differences in either F0 or spectral slope allowed listeners to more easily distinguish between harmonic stimuli, and thus group them together less. These findings suggest that pitch/timbre difference cues play an important role in how we perceive harmonic sounds in an auditory stream, representing our ability to group or segregate human voices in a multi-talker listening environment. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) is a central driver of many processes in aquatic environments. Here, we address the issue of spatial and temporal variations in DOM quantity and quality in a deep tropical lake (Brazil). We measure DOC, Chl-a, suspended solids, nutrients and CDOM metrics in surface water samples taken from 21 sampling sites during six campaigns, and we quantify their links with water depth and rainfall estimates. Temporal effects explain between 74.5 and 94.5% of the variance in DOC, SUVA254, aCDOM440, and Chl-a, and all those parameters were influenced by rainfall. In contrast, spatial variations affect more S275-295 and aCDOM254. The contributing drainage area varies spatially in morphology and geometry, and each portion affects a specific part of the lake, resulting in a spatial variation in DOM quantity and quality. Our findings demonstrate the importance of the input of allochthonous DOM (which depends on seasonal rainfall and drainage area shape) to DOM dynamics in a tropical lake. The study area is receiving lower rates of precipitation in recent times, and our results suggest that this may alter the seasonal patterns of input of DOM and nutrients in the lake, with possible impacts on water quality, aquatic biota and ecosystem functioning. [ABSTRACT FROM AUTHOR]

In multi-talker listening environments, the culmination of different voice streams may lead to the distortion of each source’s individual message, causing deficits in comprehension. Voice characteristics, such as pitch and timbre, are major dimensions of auditory perception and play a vital role in grouping and segregating incoming sounds based on their acoustic properties. The current study investigated how pitch and timbre cues (determined by fundamental frequency, notated as F0, and spectral slope, respectively) can affect perceptual integration and segregation of complex-tone sequences within an auditory streaming paradigm. Twenty normal-hearing listeners participated in a traditional auditory streaming experiment using two alternating sequences of harmonic tone complexes A and B with manipulating F0 and spectral slope. Grouping ranges, the F0/spectral slope ranges over which auditory grouping occurs, were measured with various F0/spectral slope differences between tones A and B. Results demonstrated that the grouping ranges were maximized in the absence of the F0/spectral slope differences between tones A and B and decreased by 2 times as their differences increased to ±1-semitone F0 and ±1-dB/octave spectral slope. In other words, increased differences in either F0 or spectral slope allowed listeners to more easily distinguish between harmonic stimuli, and thus group them together less. These findings suggest that pitch/timbre difference cues play an important role in how we perceive harmonic sounds in an auditory stream, representing our ability to group or segregate human voices in a multi-talker listening environment.

It has been suggested that aesthetically pleasing stimuli are processed efficiently by the visual system, whereas uncomfortable stimuli are processed inefficiently. This study consists of a series of three experiments investigating this idea using a range of images of abstract artworks, photographs of natural scenes, and computer‐generated stimuli previously shown to be uncomfortable. Subjective judgements and neural correlates were measured using electroencephalogram (EEG) (steady‐state visual evoked potentials, SSVEPs). In addition, global image statistics (contrast, Fourier amplitude spectral slope and fractal dimension) were taken into account. When effects of physical image contrast were controlled, fractal dimension predicted discomfort judgements, suggesting the SSVEP response is more likely to be influenced by distribution of edges than the spectral slope. Importantly, when effects of physical contrast and fractal dimension were accounted for using linear mixed effects modelling, SSVEP responses predicted subjective judgements of images. Specifically, when stimuli were not matched for perceived contrast, there was a positive relationship between SSVEP responses and how pleasing a stimulus was judged to be, and conversely a negative relationship between discomfort and SSVEP response. This is significant as it shows that the neural responses in early visual areas contribute to the subjective (un)pleasantness of images, although the results of this study do not provide clear support for the theory of efficient coding as the cause of perceived pleasantness or discomfort of images, and so other explanations need to be considered. [ABSTRACT FROM AUTHOR]

Summary: Over the last two decades, our understanding of clinical and pathophysiological aspects of sleep‐related epileptic and non‐epileptic paroxysmal behaviours has improved considerably, although it is far from complete. Indeed, even if many core characteristics of sleep‐related hypermotor epilepsy and non‐rapid eye movement parasomnias have been clarified, some crucial points remain controversial, and the overlap of the behavioural patterns between these disorders represents a diagnostic challenge. In this work, we focused on segments of multichannel sleep electroencephalogram free from clinical episodes, from two groups of subjects affected by sleep‐related hypermotor epilepsy (N = 15) and non‐rapid eye movement parasomnias (N = 16), respectively. We examined sleep stages N2 and N3 of the first part of the night (cycles 1 and 2), and assessed the existence of differences in the periodic and aperiodic components of the electroencephalogram power spectra between the two groups, using the Fitting Oscillations & One Over f (FOOOF) toolbox. A significant difference in the gamma frequency band was found, with an increased relative power in sleep‐related hypermotor epilepsy subjects, during both N2 (p <.001) and N3 (p <.001), and a significant higher slope of the aperiodic component in non‐rapid eye movement parasomnias, compared with sleep‐related hypermotor epilepsy, during N3 (p =.012). We suggest that the relative power of the gamma band and the slope extracted from the aperiodic component of the electroencephalogram signal may be helpful to characterize differences between subjects affected by non‐rapid eye movement parasomnias and those affected by sleep‐related hypermotor epilepsy. [ABSTRACT FROM AUTHOR]

Oceanic geostrophic turbulence theory predicts significant inverse kinetic energy (KE) cascades at scales larger than the energy injection wavelength. However, the characteristics of the mesoscale variabilities associated with the inverse KE cascade in the real oceans have not been clear enough up to now. To further examine this problem, we analyzed the spectral characteristics of the oceanic mesoscale motions over the scales of inverse KE cascades based on high-resolution gridded altimeter data. The applicability of the quasigeostrophic (QG) turbulence theory and the surface quasigeostrophic (SQG) turbulence theory in real oceans is further explored. The results show that the sea surface height (SSH) spectral slope is linearly related to the eddy-kinetic-energy (EKE) level with a high correlation coefficient value of 0.67. The findings also suggest that the QG turbulence theory is an appropriate dynamic framework at the edge of high-EKE regions and that the SQG theory is more suitable in tropical regions and low-EKE regions at mid-high latitudes. New anisotropic characteristics of the inverse KE cascade are also provided. These results indicate that the along-track spectrum used by previous studies cannot reveal the dynamics of the mesoscale variabilities well. [ABSTRACT FROM AUTHOR]

Absorption spectra of coloured dissolved organic matter (CDOM) and their derived parameters such as, absorption coefficient and spectral slopes are useful to study the molecular weight distribution of DOM. Here CDOM absorption characteristics were assessed in two distributaries [Gautami (GGE) and Vasishta (VGE)] of the Godavari estuary to examine the differences in molecular weight characterization of CDOM and its origin with reference to the geomorphological features during post southwest monsoon (PSM), late northeast monsoon (LNM) and early southwest monsoon (ESM) seasons. In VGE, absorption coefficient (aCDOM350) exhibited significant negative correlation with total suspended matter (TSM) and salinity during PSM and LNM due to the local anthropogenic inputs. In GGE, the values of spectral slope S275–295, and S350–400 were low and high, respectively during PSM, indicating the presence of pronounced terrestrial derived organic matter. In VGE, S350–400 showed increasing and decreasing trends from upstream to downstream in surface and bottom waters respectively during LNM, indicating that organic matter originated through in-situ microbiological processes. The spectral slope ratio, SR (S275–295/S350–400) was higher in GGE during LNM (Avg ± SD = 1.19 ± 0.14) and ESM (1.47 ± 0.27), which suggests the lower molecular weight organic matter formation through microbiological and photodegradation processes. However, in VGE, the values of SR during LNM (1.04 ± 0.11) and ESM (1.08 ± 0.17) were low, which indicates higher molecular weight organic matter formation due to biological production driven by local anthropogenic inputs or aquaculture effluents. Research highlights: This is first of its kind on the absorption characteristics of coloured dissolved organic matter (CDOM) with reference to the different geomorphological features of Godavari estuary. Seasonal variation in the molecular weight characteristics of CDOM were studied in the Gautami and Vasishta Godavari estuaries. High molecular weight terrestrial derived organic matter was more pronounced in the river dominated Gautami Godavari estuary during post southwest monsoon season. High molecular weight in situ produced organic matter was more in the wave dominated Visishta Godavari estuary during late northeast and early southwest monsoon seasons driven by anthropogenic or aquaculture inputs. [ABSTRACT FROM AUTHOR]

• Dysarthria and control differ in AmpD, CoG, SD, and skewness. • Apraxia and control differ in AmpD, SD, and rounded CoG and kurtosis. • Dysarthria and apraxia differ in AmpD, CoG, and skewness. • AmpD and CoG are higher in the unrounded context for all groups. • AmpD, CoG, SD, skewness and kurtosis differs by sex in healthy speech. This study examines whether there are differences in the speech of speakers with dysarthria, speakers with apraxia and healthy speakers in spectral acoustic measures during production of the central-peninsular Spanish alveolar sibilant fricative /s/. To this end, production of the sibilant was analyzed in 20 subjects with dysarthria, 8 with apraxia of speech and 28 healthy speakers. Participants produced 12 sV(C) words. The variables compared across groups were the fricative's spectral amplitude difference (AmpD) and spectral moments in the temporal midpoint of fricative execution. The results indicate that individuals with dysarthria can be distinguished from healthy speakers in terms of the spectral characteristics AmpD, standard deviation (SD), center of gravity (CoG) and skewness, the last two in context with unrounded vowel, while no differences in kurtosis were detected. Participants with AoS group differ significantly from healthy speaker group in AmpD, SD and CoG and Kurtosis, the first one followed unrounded vowel and the latter two followed by rounded vowels. In addition, speakers with apraxia of speech group returned significant differences with respect to speakers with dysarthria group in AmpD, CoG and skewness. The differences found between the groups in the measures studied as a function of the type of vowel context could provide insights into the distinctive manifestations of motor speech disorders, contributing to the differential diagnosis between apraxia and dysarthria in motor control processes. [ABSTRACT FROM AUTHOR]

Spectral analysis of terrain height variance is conducive to quantitatively study the terrain characteristics and grid-size selection for mesoscale models. Improved topographic resolutions can lead to the variations of terrain characteristics and the appropriate grid size for a fixed analyzed area. Spectral methods of one-dimensional weighted average and arithmetic mean were used to investigate the specific impact on the distribution of terrain spectra and grid-size selection for mesoscale models of the landslide-prone areas in western Sichuan. The results indicate that the maximum spectral energy (the variance of the terrain height series) of 30″ resolution (R1) is larger than that of 90 m resolution (R2), indicating a gentler undulation of terrain for R2. The spectral curve of R2 almost overlaps with that of R1 because the difference in topographic resolution does not change the dominant distribution of the topography. Their differing spectral energies at longer wavelengths are related to the majority of grid points of R2 distributed at shorter wavelength bands. A least squares fit in the form of S=aλb was used to estimate the decreasing trend of the spectral distribution. The difference in spectral slope between R1 and R2 is mainly caused by the spectral energy of R2 at shorter wavelengths. The exponent b is connected with grid-size selection for mesoscale models. A universal horizontal grid size of 2.5 km for R1 and 1.9 km for R2 are required to resolve 95% of the terrain height variance for a mesoscale model application without a subgrid-scale parameterization. The simulation tests show that the improved topographic resolution appears to perform better in reproducing precipitation, which is probably related to the finer details of the terrain recognized by the model.

The slope of the electroencephalography (EEG) power spectrum (also referred to as 1/f noise) is an important consideration when calculating narrow-band power. However, psychophysiological data also suggest this slope is a meaningful signal itself, not merely background activity or noise. We present two different methods for quantifying the slope of the power spectrum and assess their reliability and sensitivity. We used data from N = 60 participants who had EEG collected during rest, a videogame task, and a second period of rest. At all phases of the experiment, we calculated the "spectral slope" (a regression-based method fit to all datapoints) and the "aperiodic slope" (estimated with the fitting oscillations with 1/f algorithm FOOOF). For both methods we assessed: their reliability, their sensitivity to the transition from rest to task, their sensitivity to changes during the videogame task itself, and the agreement between the two measures. Across resting phases, both spectral and aperiodic slopes showed a high degree of reliability. Both methods also showed a steepening of the power spectrum on-task compared to rest. There was also a high degree of consistency between the two methods in their estimate of the underlying slope, but FOOOF explained more variance in the power spectra across regions and type of activity (rest versus task). The slope of the power spectrum is a highly reliable individual difference and sensitive to within-subject changes across two different methods of estimation. Moving forward, we generally recommend the use of the FOOOF algorithm for its ability to account for narrow-band signals, but these data show how regression-based approaches produce similar estimates of the spectral slope, which may be useful in some applications. [ABSTRACT FROM AUTHOR]

Optical surrogates, derived from absorbance and fluorescence spectra, are widely used to infer dissolved organic matter (DOM) composition (molecular weight, aromaticity) and genesis (autochthonous vs allochthonous). Despite the broad adoption of optical surrogates, several limitations exist, such as context- and sample-specific factors. These limitations create uncertainty about how compositional interpretations based on optical surrogates are generalized across contexts, specifically if there is duplicative or contradictory information in those interpretations. To explore these limitations, we performed a meta-analysis of optical surrogates for DOM from diverse sources, both from natural systems and after water treatment processes ( n = 762). Prior to analysis, data were screened using a newly developed, standardized methodology that applies systematic quality control criteria before reporting surrogates. There was substantial overlap in surrogate values from natural and treated samples, suggesting that the gradients governing the surrogate variability can be generated in both contexts. This overlap provides justification for using optical surrogates originally developed in the context of natural systems to describe DOM changes in engineered systems, although the interpretations may change. Absorbance-based surrogates that describe the amount of spectral tailing (e.g., E2:E3 and S 275-295 ) had a high frequency of strong correlations with one another but not to specific absorbance (SUVA 254 ) or absorbance slope ratio ( S R ). The fluorescence index (FI) and biological index (β/α) were strongly correlated with one another and to the peak emission wavelength but not to the humification index (HIX). Although SUVA 254 and FI have both been correlated to DOM aromaticity in prior research, there was a lack of reciprocity between these optical surrogates across this data set. Additionally, there were patterns of deviations in the wastewater subset, suggesting that effluent organic matter may not follow conventional interpretations, urging caution in the use of optical surrogates to track DOM in water reuse applications. Finally, the meta-analysis highlights that three aspects should be captured when optical spectra are used for DOM interpretation: specific absorbance, absorbance tailing, and the extent of red-shifted fluorescence. We recommend that SUVA 254 , E2:E3, and FI or β/α be prioritized in future DOM studies to capture these aspects, respectively.

Nonoscillatory measures of brain activity such as the spectral slope and Lempel-Ziv complexity are affected by many neurological disorders and modulated by sleep. A multitude of frequency ranges, particularly a broadband (encompassing the full spectrum) and a narrowband approach, have been used especially for estimating the spectral slope. However, the effects of choosing different frequency ranges have not yet been explored in detail. Here, we evaluated the impact of sleep stage and task engagement (resting, attention, and memory) on slope and complexity in a narrowband (30-45 Hz) and broadband (1-45 Hz) frequency range in 28 healthy male human subjects (21.54 ± 1.90 years) using a within-subject design over 2 weeks with three recording nights and days per subject. We strived to determine how different brain states and frequency ranges affect slope and complexity and how the two measures perform in comparison. In the broadband range, the slope steepened, and complexity decreased continuously from wakefulness to N3 sleep. REM sleep, however, was best discriminated by the narrowband slope. Importantly, slope and complexity also differed between tasks during wakefulness. While narrowband complexity decreased with task engagement, the slope flattened in both frequency ranges. Interestingly, only the narrowband slope was positively correlated with task performance. Our results show that slope and complexity are sensitive indices of brain state variations during wakefulness and sleep. However, the spectral slope yields more information and could be used for a greater variety of research questions than Lempel-Ziv complexity, especially when a narrowband frequency range is used., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 Höhn et al.)

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterized by hyperactivity/impulsivity and inattentiveness. Efforts toward the development of a biologically based diagnostic test have identified differences in the EEG power spectrum; most consistently reported is an increased ratio of theta to beta power during resting state in those with the disorder, compared with controls. Current approaches calculate theta/beta ratio using fixed frequency bands, but the observed differences may be confounded by other relevant features of the power spectrum, including shifts in peak oscillation frequency and altered slope or offset of the aperiodic 1/f-like component of the power spectrum. In the present study, we quantify the spectral slope and offset, peak alpha frequency, and band-limited and band-ratio oscillatory power in the resting-state EEG of 3- to 7-yr-old children with and without ADHD. We found that medication-naive children with ADHD had higher alpha power, greater offsets, and steeper slopes compared with typically developing children. Children with ADHD who were treated with stimulants had comparable slopes and offsets to the typically developing group despite a 24-h medication-washout period. We further show that spectral slope correlates with traditional measures of theta/beta ratio, suggesting the utility of slope as a neural marker over and above traditional approaches. Taken with past research demonstrating that spectral slope is associated with executive functioning and excitatory/inhibitory balance, these results suggest that altered slope of the power spectrum may reflect pathology in ADHD. [ABSTRACT FROM AUTHOR]

Riverine dissolved organic carbon (DOC) and its optical properties were investigated in two sub-river basins (Yeniugou and Hulugou river) of the Upper Heihe river basin in the northern Tibetan Plateau. The results showed that DOC concentrations ranged from 0.25 to 12.2 and 0.18–1.04 mg L−1 for Yeniugou and Hulugou river basin with an average of 0.82 and 0.33 mg L−1, respectively. Export of DOC from the studied river (YNG: ~0.86 Gg C yr−1) was lesser compared with other large river in the Tibetan Plateau and Arctic regions because of the small drainage area and lower DOC concentrations. There exhibited significant seasonality for DOC in Yeniugou river basin with higher values observed during late spring and summer; however, no such distinct trend was observed for DOC in the studied rivers of Hulugou river basin. In contrast, total dissolved nitrogen showed a slightly lower value during the summer season. A strong relationship was determined between DOC concentrations and spectral UV absorbance at 254 nm (SUVA 254), absorption coefficients and spectral slope for both sub-river basins, attributing that the riverine DOM in the northern Tibetan Plateau has a remarkably high content of aromatic compounds in late spring and summer. Considering the less snow cover percentage, this study highlights the potential impacts of permafrost thaw on the riverine DOC and its characteristics in the permafrost region under climate change. Unlabelled Image • Riverine dissolved organic carbon in the northern Tibetan Plateau was investigated. • DOC in Yeniugou river basin showed higher values in late spring and summer. • Optical characteristics of riverine DOC indicated high aromatic compounds in summer. • Considering less snow cover in the studied area, riverine DOC may be mostly affected by permafrost thaw. [ABSTRACT FROM AUTHOR]

The quantity and character of dissolved organic matter (DOM) can change rapidly during storm events, affecting key biogeochemical processes, carbon bioavailability, metal pollutant transport, and disinfection byproduct formation during drinking water treatment. We used in situ ultraviolet–visible spectrophotometers to concurrently measure dissolved organic carbon (DOC) concentration and spectral slope ratio, a proxy for DOM molecular weight. Measurements were made at 15-minute intervals over three years in three streams draining primarily agricultural, urban, and forested watersheds. We describe storm event dynamics by calculating hysteresis indices for DOC concentration and spectral slope ratio for 220 storms and present a novel analytical framework that can be used to interpret these metrics together. DOC concentration and spectral slope ratio differed significantly among sites, and individual storm DOM dynamics were remarkably variable at each site and among the three sites. Distinct patterns emerged for storm DOM dynamics depending on land use/land cover (LULC) of each watershed. In agricultural and forested streams, DOC concentration increased after the time of peak discharge, and spectral slope ratio dynamics indicate that this delayed flux was of relatively higher molecular weight material compared to the beginning of each storm. In contrast, DOM character during storms at the urban stream generally shifted to lower molecular weight while DOC concentration increased on the falling limb, indicating either the introduction of lower molecular weight DOM, the exhaustion of a higher molecular weight DOM sources, or a combination of these factors. We show that the combination of high-frequency DOM character and quantity metrics have the potential to provide new insight into short-timescale DOM dynamics and can reveal previously unknown effects of LULC on the chemical nature, source, and timing of DOM export during storms. [ABSTRACT FROM AUTHOR]

Highlights • Correlations between personality traits and speech features were observed. • Results suggest a speech task-dependent behaviour of the observed correlations. • A negative-skewed behaviour of F 0 distribution correlated with Sociability score. • Prosodic production correlated to both Alexithymia scores and Activity trait. • Voice quality correlated with Impulsive Sensation Seeking and Aggression-Hostility. Abstract Voice signal has been widely investigated to characterize mood and emotional states. A further interesting dimension could regard the personality traits. The relationship between personality traits and specific speech features is known, however this topic requires further investigation. Specifically, most studies are focused on perceived personality traits, without adopting dedicated personality tests. Moreover, the relationship among speaker personality traits and specific speech features have still to be clarified. In this study, a correlational analysis between some speech-related features and the personality traits, as described by the Zuckerman-Kuhlman model and the Toronto Alexithymia Scale, is performed. An experimental protocol, consisting of two structured speech tasks, was administered to eighteen healthy subjects. Speech features were estimated to describe fundamental frequency (F 0) and voice quality related features from whole speech recording and tilt-related features, describing F 0 dynamics at voiced segment level. Significant correlations among personality traits and speech features were observed using both feature sets. Interestingly, the adopted speech task was found to influence the obtained results. Specifically, no feature reports the same significant correlation in both adopted tasks. The impact of personality traits and speech production studies on the characterization of mental disorders and the estimation of emotional/mood state of the speaker are discussed. [ABSTRACT FROM AUTHOR]

Despite their mutually exclusive definitions, pitch and timbre perception interact with each other in normal-hearing (NH) listeners. Cochlear implant (CI) users have worse than normal pitch and timbre perception. However, the pitch-timbre interaction with CIs is not well understood. This study tested the interaction between pitch and sharpness (an aspect of timbre) perception related to the fundamental frequency (F0) and spectral slope of harmonic complex tones, respectively, in both NH listeners and CI users. In experiment 1, the F0 (and spectral slope) difference limens (DLs) were measured with a fixed spectral slope (and F0) and 20-dB amplitude roving. Then, the F0 and spectral slope were varied congruently or incongruently by the same multiple of individual DLs to assess the pitch and sharpness ranking sensitivity. Both NH and CI subjects had significantly higher pitch and sharpness ranking sensitivity with congruent than with incongruent F0 and spectral slope variations, and showed a similar symmetric interaction between pitch and timbre perception. In experiment 2, CI users' melodic contour identification (MCI) was tested in three spectral slope (no, congruent, and incongruent spectral slope variations by the same multiple of individual DLs as the F0 variations) and two amplitude conditions (0- and 20-dB amplitude roving). When there was no amplitude roving, the MCI scores were significantly higher with congruent than with no, and in turn than with incongruent spectral slope variations. The 20-dB amplitude roving significantly reduced the overall MCI scores and the effect of spectral slope variations. These results reflected a confusion between higher (or lower) pitch and sharper (or duller) timbre and offered important implications for understanding and enhancing pitch and timbre perception with CIs. [ABSTRACT FROM AUTHOR]

Abstract The Marmara Sea is a semi-enclosed basin connecting the Black and the Mediterranean Seas through the Bosporus and Dardanelles Straits (Turkish Straits System- TSS). It is characterized by a permanent two layered counter-flow caused by the exchange of water masses between the Black and Mediterranean Seas. In this study we focus on the role of the Marmara Sea in altering the optical characteristics of dissolved organic matter (DOM) during its transport through the TSS. We use detailed absorbance and fluorescence measurements followed by parallel factor analysis (PARAFAC). PARAFAC identified four components: a primary terrestrial humic C1 (ex/em 255/448 nm), a marine humic C2 (ex/em 300/402 nm), a secondary terrestrial humic C3 (ex/em 280, 370/480 nm) and a protein like component C4 (ex/em 275/336 nm). The above halocline waters (≤25 m) of Black Sea origin are characterized by high DOC (114–181 μmol L−1); high CDOM absorption (aCDOM(300): 1.97–2.92 m−1), low absorption spectral slope (S 275–295 : 0.0280–0.0307 nm−1) and high humic content. In this water layer, interrelationships with salinity, DOC and optical parameters revealed that although bulk DOC is diluted towards the west, transformations of the DOM pool are related to several processes. In the sub-halocline waters (>25–1250 m) of Mediterranean origin, all measured parameters are significantly lower (DOC: 55–65 μmo L−1; aCDOM(300): 0.46–0.80 m−1; S 275–295 : 0.0241–0.0376 nm−1). No relationship of DOC with apparent oxygen utilization (AOU) could be established, likely due to the proliferation of particles. Nevertheless, qualitative changes of DOM could be traced by the negative relationship of S 275–295 with AOU and the two fold increase of the intensities of the humic-like components towards the eastern part of the basin. This suggests that the optical signature of the Mediterranean DOM is altered in the deep Marmara Sea despite its constant DOC content. Highlights • DOC shows conservative mixing in the brackish layer of the Marmara Sea. • a 300 and S 275–295 reveal CDOM microbial transformation in the above halocline layer. • DOC distribution in the sub-halocline water is not explained by the AOU. • S 275–295 and peak C reveal humification in the sub-halocline layer. • Sub-halocline DOM loses its Mediterranean character increasing its optical signal. [ABSTRACT FROM AUTHOR]

Research to date has not found strong evidence for a universal link between any single low-level image statistic, such as fractal dimension or Fourier spectral slope, and aesthetic ratings of images in general. This study assessed whether different image statistics are important for artistic images containing different subjects and used partial least squares regression (PLSR) to identify the statistics that correlated most reliably with ratings. Fourier spectral slope, fractal dimension and Shannon entropy were estimated separately for paintings containing landscapes, people, still life, portraits, nudes, animals, buildings and abstracts. Separate analyses were performed on the luminance and colour information in the images. PLSR fits showed shared variance of up to 75% between image statistics and aesthetic ratings. The most important statistics and image planes varied across genres. Variation in statistics may reflect characteristic properties of the different neural sub-systems that process different types of image.