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Efficient soybean mapping is critical for agricultural production and yield prediction. However, current sample-driven soybean mapping methods heavily rely on large representative sample datasets, limiting the interpretability of physical mechanisms. Besides, sample-free methods failed to exploit key features that differentiate soybean from other crops, especially Chlorophyll content. Misclassification errors persist and spatiotemporal generalization remains limited. Therefore, this study develops a novel Soybean Mapping Composite Index (SMCI) within a precise Global Optimal Time Window (GOTW). It integrates unique features of soybean Chlorophyll content, canopy water content, and canopy greenness by coupling three red-edge bands (RE2, RE3, and RE4), one near-infrared band, one shortwave infrared band, and two feature indices (Enhanced Vegetation Index and Green Chlorophyll Vegetation Index). The novel index was applied to soybean mapping at six sites in four major soybean producing countries (China, Argentina, Brazil, and the United States) from 2019 to 2021, using an optimal threshold of 3.25. Within the GOTW, the index responds better to spectral features and improves soybean separability. The average overall accuracy (OA: 91%) and average Kappa coefficient (Kappa: 0.83) for the novel index at all sites outperformed the traditional sample-driven Random Forest (RF) method (OA: 84%, Kappa: 0.70) and the existing sample-free index-based Greenness and Water Content Composite Index (GWCCI) (OA: 81%, Kappa: 0.64). Furthermore, interannual transfer experiments consistently showed high accuracy, demonstrating robust spatiotemporal transferability. The proposed SMCI index meets the need for a lightweight and stable soybean mapping tool and serves as a valuable reference for efficient global crop mapping. [ABSTRACT FROM AUTHOR]

Environmental factors, such as culture, are known to shape individual variation in brain activity including spontaneous activity, but less is known about their population-level effects. Eastern and Western cultures differ strongly in their cultural norms about relationships between individuals. For example, the collectivism, interdependence and tightness of Eastern cultures relative to the individualism, independence and looseness of Western cultures, promote interpersonal connectedness and coordination. Do such cultural contexts therefore influence the group-level variability of their cultural members' spontaneous brain activity? Using novel methods adapted from studies of inter-subject neural synchrony, we compare the group-level variability of resting state EEG dynamics in Chinese and Canadian samples. We observe that Chinese subjects show significantly higher inter-subject correlation and lower inter-subject distance in their EEG power spectra than Canadian subjects, as well as lower variability in theta power and alpha peak frequency. We demonstrate, for the first time, different relationships among subjects' resting state brain dynamics in Chinese and Canadian samples. These results point to more idiosyncratic neural dynamics among Canadian participants, compared with more shared neural features in Chinese participants. [ABSTRACT FROM AUTHOR]

An approach is developed to study temporal behavior of the active region overheating in high-power semiconductor lasers (λ = 1060 nm) with an ultrawide aperture (800 μm) operating in a quasi-continuous regime of pumping by current pulses with an amplitude of 21 A, a duration of 1 ms, and a repetition rate of 10 Hz. The approach is based on measuring the lasing dynamics with spectral selection. The lasing spectrum analysis shows that the region of the rising edge, where the amplitude of the current pulse increases, is characterized by a maximum red-shift rate of 30 nm ms–1, which is due to both thermal and nonthermal effects. The pulse region corresponding to a constant pump current amplitude is characterized only by a thermal red shift of the lasing spectrum long-wavelength edge at a rate of ~1 nm ms–1. The obtained experimental active region overheating is 2.78°C for the constant pump current amplitude range, which agrees with the calculated overheating of 3.08°C for the pump conditions under study. [ABSTRACT FROM AUTHOR]

The discriminating information about dysarthria exists at the fine level in the short-time Fourier transform magnitude spectra (STFT-MS). To capture the discriminating information present in STFT-MS using Mel-frequency cepstral coefficients (MFCCs), this paper firstly studied the role of increasing the size of Mel-filterbank and inverse Mel-filterbank. A novel feature extraction technique is then proposed for the assessment of dysarthria using speech. In the proposed approach, the STFT-MS is processed through an accumulator (digital integrator) to capture the spectral dynamics (SD). The accumulator output over a frequency range is a growing or decaying function of frequency depending on the peaks and valleys present within that region due to the pitch and resonance structure of the vocal tract system. The SD over a band of frequency is computed from the accumulator output by finding non-local differences between frequency points placed linearly in non-overlapping mode. The SDs are logarithmically compressed (LCSD) to normalize the magnitude of SD computed in different frequency regions. The LCSD represents (M) dimensional feature vector when it is computed at M linearly spaced frequency points. The i-vector-based dysarthric-level assessment system on the universal access speech reported in this study shows that the performance of the MFCC feature improves significantly by increasing the Mel-filterbank size. The MFCCs computed from the inverse Mel-filterbank (IMFCCs) contain additional information to MFCCs. The use of LCSD provides improved performance than MFCCs and IMFFCs and is also provides additional to MFCCs. [ABSTRACT FROM AUTHOR]

Southern varieties of English are known to be affected by the Southern Vowel Shift (SVS), which alters the positional relationship between the front tense/lax system. However, previous work on the SVS generally limits its focus to steady state formant measures. Possible links between these shifts and dynamic trajectory distinctions have largely been unexplored despite widespread recognition that Southern vowels are dynamic in nature. The current article uses data from three Southern states (Tennessee, North Carolina, and Virginia) to ask to what extent does spectral onset position (the typical measure of SVS participation) correlate with internal spectral dynamics in the SVS. Analysis methods include a series of spectral measures (vector length, trajectory length, spectral rate of change and vector angle), which capture vowel inherent dynamics and vowel directionality. Results support the utility of looking at dynamic measures to better understand the fuller extent of vowel changes that occur with the SVS and lend support to recent calls to include nonstatic measures in sociophonetic analyses more generally. [ABSTRACT FROM AUTHOR]

Important information about the state dynamics of the brain during anesthesia is unraveled by Electroencephalogram (EEG) approaches. Patterns that are observed through EEG related to neural circuit mechanism under different molecular targets dependent anesthetics have recently attracted much attention. Propofol, a Gamma-amino butyric acid, is known with evidently increasing alpha oscillation. Desflurane shares the same receptor action and should be similar to propofol. To explore their dynamics, EEG under routine surgery level anesthetic depth is analyzed using multitaper spectral method from two groups: propofol (n = 28) and desflurane (n = 23). The time-varying spectrum comparison was undertaken to characterize their properties. Results show that both of the agents are dominated by slow and alpha waves. Especially, for increased alpha band feature, propofol unconsciousness shows maximum power at about 10 Hz (mean ± SD; frequency: 10.2 ± 1.4 Hz; peak power, -14.0 ± 1.6 dB), while it is approximate about 8 Hz (mean ± SD; frequency: 8.3 ± 1.3 Hz; peak power, -13.8 ± 1.6 dB) for desflurane with significantly lower frequency-resolved spectra for this band. In addition, the mean power of propofol is much higher from alpha to gamma band, including slow oscillation than that of desflurane. The patterns might give us an EEG biomarker for specific anesthetic. This study suggests that both of the anesthetics exhibit similar spectral dynamics, which could provide insight into some common neural circuit mechanism. However, differences between them also indicate their uniqueness where relevant. [ABSTRACT FROM AUTHOR]

A mathematical model of multistep photoinduced electron transfer (PET) in a polar medium with a single relaxation time (Debye solvent) is developed. The model includes the polarization nonequilibrity formed in the vicinity of the donor-acceptor molecular system at the initial steps of photoreaction and its influence on the subsequent steps of PET. It is established that the results from numerical simulation of transient luminescence spectra of photoexcited donor-acceptor complexes (DAC) conform to calculated data obtained on the basis of the familiar experimental technique used to measure the relaxation function of solvent polarization in the vicinity of DAC in the picosecond and subpicosecond ranges. [ABSTRACT FROM AUTHOR]

Photonic band crystal semiconductor lasers generating gain-switched picosecond pulses in the 1060-nm spectral range are demonstrated. The unique ultra-broad laser waveguide allows the simultaneous delivery of high output power and high beam quality, enabling the generation of optical pulses with peak brightness up to 130 MWcm ^-2 sr ^-1 . The spectral dynamics are investigated by external filtering of the laser emission. The effects of the filter bandwidth and central wavelength on the resulting optical pulse characteristics are identified. By properly chosen filter parameters, it is found that the higher order relaxation oscillation part of the optical pulse is completely suppressed even at the highest injected pulse currents, also resulting in a pulse width reduction down to less than 21.5 ps. [ABSTRACT FROM PUBLISHER]

Brain regions that respond to more than one sensory modality are characterized as multisensory regions. Studies on the processing of shape or object information have revealed recruitment of the lateral occipital cortex, posterior parietal cortex, and other regions regardless of input sensory modalities. However, it remains unknown whether such regions show similar (modality-invariant) or different (modality-specific) neural oscillatory dynamics, as recorded using magnetoencephalography (MEG), in response to identical shape information processing tasks delivered to different sensory modalities. Modality-invariant or modality-specific neural oscillatory dynamics indirectly suggest modality-independent or modality-dependent participation of particular brain regions, respectively. Therefore, this study investigated the modality-specificity of neural oscillatory dynamics in the form of spectral power modulation patterns in response to visual and tactile sequential shape-processing tasks that are well-matched in terms of speed and content between the sensory modalities. Task-related changes in spectral power modulation and differences in spectral power modulation between sensory modalities were investigated at source-space (voxel) level, using a multivariate pattern classification (MVPC) approach. Additionally, whole analyses were extended from the voxel level to the independent-component level to take account of signal leakage effects caused by inverse solution. The modality-specific spectral dynamics in multisensory and higher-order brain regions, such as the lateral occipital cortex, posterior parietal cortex, inferior temporal cortex, and other brain regions, showed task-related modulation in response to both sensory modalities. This suggests modality-dependency of such brain regions on the input sensory modality for sequential shape-information processing. [ABSTRACT FROM AUTHOR]

• Noise-like square pulse obtains a square shape in the spectral domain. • The pulse demonstrates a spectral resonance with a 3-dB variation: 10–20 nm. • Simulation approximately reproduced the flat-topped spectra and spectral resonance. • Analysis shows that the flat gain dispersion accounts for the flat spectral peaks. We report the generation of a series of noise-like square pulses (NLSPs) at 2 μm in a figure-8 Tm-doped fiber laser. The NLSP demonstrates a square shape as well in the spectral domain and possesses a resonant property in spectrum similar to that in time. The spectral resonance ranges from 10 nm to about 20 nm under an appropriate control of polarization, an indication of its wide mode-locking regime. The unique spectral dynamics exhibits a strong polarization dependence, subject to the nonlinear mode-locking mechanism. A subsequent numerical simulation shows that a uniform gain dispersion distribution accounts for the forming of the flat-topped spectra. [ABSTRACT FROM AUTHOR]

Sounds in the natural environment form an important class of biologically relevant non-stationary signals. We propose a dynamic spectral measure to characterize the spectral dynamics of such non-stationary sound signals and classify them based on rate of change of spectral dynamics. We categorize sounds with slowly varying spectral dynamics as simple and those with rapidly changing spectral dynamics as complex. We propose rate of spectral dynamics as a possible scheme to categorize sounds in the environment. [ABSTRACT FROM AUTHOR]

Abstract: We are concerned with the critical threshold phenomena in the restricted Euler (RE) equations. Using the spectral and trace dynamics we identify the critical thresholds for the 3D and 4D restricted Euler equations. It is well known that the 3D RE solutions blow up. Projected on the 3-sphere, the set of initial eigenvalues which give rise to bounded stable solutions is reduced to a single point, which confirms that the 3D RE blowup is generic. In contrast, we identify a surprisingly rich set of the initial spectrum on the 4-sphere which yields global smooth solutions; thus, 4D regularity is generic. [Copyright &y& Elsevier]

We study the influence of a scanning nano-electrode on the fluorescence excitation spectra of single terrylene molecules embedded in thin p-terphenyl films at cryogenic temperatures. We show that applied voltages of less than 10 V can result in reversible Stark shifts of up to 100 times and a linewidth increase greater than 10 times the natural linewidth. We discuss the potential of our experimental scheme for the direct imaging of individual two-level systems in the nanometer vicinity of single molecules. [ABSTRACT FROM AUTHOR]

Sounds in the natural environment are non-stationary, in that their spectral dynamics is time-dependent. We develop measures to analyze the spectral dynamics of environmental sound signals and find that they fall into two categories—simple sounds with slowly varying spectral dynamics and complex sounds with rapidly varying spectral dynamics. Based on our results and those from auditory processing we suggest rate of spectral dynamics as a possible scheme to categorize sound signals in the environment. [ABSTRACT FROM AUTHOR]

Abstract: The structure of n-hexadecane polycrystalline matrices is examined with single molecule fluorescence spectroscopy at a temperature of 1.7K. Some single chromophores exhibit spectral dynamics during experiments: their resonances either jump between two frequencies or split into two components. By means of polarization measurements, we investigate the molecular spectra in order to distinguish between the case of two spatially unresolved molecules and the case of chromophore — two level system (TLS) pair. For closely spaced molecules two-dimensional Gaussian function fitting is applied to extract the spatial coordinates of the molecules. For TLS-chromophore systems, parameters of the TLSs are estimated. [Copyright &y& Elsevier]

A new method is evaluated for separating stimulus-locked and unlocked components of auditory event-related EEG activity. The new method uses a regression based subtraction procedure as a way to account for latency and amplitude variability within individual trials. It was applied using the oddball paradigm under conditions of active and passive listening and analyzed as spectral correlations (normalized differences) between post-stimulus epochs of standard, target or deviant stimulus conditions and silent pre-stimulus baseline activity.The regression-subtraction procedure accounted for a greater amount of variance than a method that uses linear subtraction alone. The major component of the response to auditory stimulation was an event-related synchronization in the delta and theta (2–4 Hz) frequency range. Event-related desynchronizations were also observed in the 10 Hz (alpha/mu) and in the 20–30 Hz (beta) frequency range.The regression based subtraction procedure provides better separation of stimulus-locked and unlocked components of event-related EEG activity then linear subtraction alone. Stimulus-locked and unlocked components show different patterns and topographies of effects related to attention and active discrimination. Studying both stimulus-locked and unlocked components of event-related EEG reactivity in the frequency domain provides a more comprehensive account of dynamic brain activity subserving auditory information processing. [Copyright &y& Elsevier]

A frequency-shifted feedback (FSF) laser has multi frequency components with simultaneous linear chirping in its oscillation spectrum even though the gain medium is homogeneously broadened. The spectral intensity and its bandwidth were analyzed by the proposed spectral dynamics model based on the regenerative amplification of the continuously chirped comb components with phase shift according to each round trip in the cavity. The spectral intensity peaks at an instantaneous frequency which depends on the net gain in the cavity and the gain bandwidth of atomic transition. The oscillation bandwidth is defined as the product of the saturation-broadened bandwidth and the total resonant modes contributing to the FSF operation. [ABSTRACT FROM AUTHOR]

Electrically wavelength-tunable pulses are generated from two mutually injection-seeded Fabry-Perot laser diodes at 1 GHz. By investigating the spectral dynamics, we experimentally show that stable single-mode output can be obtained after four roundtrip propagation cycles in the external cavity. We also probe the dynamic change of the spectrum during the switching between two single-mode wavelengths. It is found that the steady states can be reached after six to seven roundtrip cycles. [ABSTRACT FROM PUBLISHER]