Migration Time Research Articles

Chiral-induced covalent organic framework as novel chiral stationary phase for chiral separation using open-tubular capillary electrochromatography

As a novel class of chiral stationary phase (CPS) material, chiral covalent organic frameworks (CCOFs) have already shown great promise in open-tubular capillary electrochromatography (OT-CEC) for chiral separation. The synthesis methods of CCOFs used in OT-CEC mainly include bottom-up, post modification and chiral induction. The CCOFs synthesized by bottom-up and post modification strategies already have lots of applications in capillary electrochromatography, however, the chiral-induced synthesized via an asymmetric catalytic strategy has not yet been reported for using as the chiral stationary phase (CPS) in OT-CEC or even in chromatographic separation. Herein, the chiral-induced COF (Λ)-TpPa-1 was synthesized by asymmetric catalytic synthesis and coated on the inner surface of a capillary by an in-situ growth strategy as the CPS for chiral drug separation. The baseline separation of six enantiomers was achieved within 14 min, with a high-resolution (Rs) range from 1.85 to 6.75. Moreover, the resolution and migration time of the capillary keep stable within 160 runs, showing its superior stability and repeatability. This research provides a new idea for the development and application of novel CPS materials in the field of capillary electrochromatography separation, also shows the new application of chiral induced COFs. Furthermore, the chiral-induced CCOFs can be easily applied to other chromatographic separation fields, exhibiting its extensive application value in chiral analysis separation.

Envelope normalized reflection waveform inversion

AbstractThe reflection waveform inversion has the capability to reconstruct the background velocity model using only the reflection data by employing a migration/demigration process. Utilizing the waveform discrepancy to update the background velocity model, the conventional reflection waveform inversion method heavily relies on the true‐amplitude migration/demigration technique to reproduce the primary amplitude information from the observed reflections. We can reproduce the amplitude of observed reflections by performing least‐squares reverse time migration to estimate the reflectivity in each iteration. However, this strategy is quite time‐consuming. To avoid the need for the true‐amplitude migration/demigration or least‐squares reverse time migration, we develop an amplitude‐independent reflection waveform inversion method that uses an envelope‐normalized objective function. The envelope‐normalized waveform difference can extract the phase residuals accurately as a function of time. Compared with the global energy–normalized misfit, our proposed envelope‐normalized objective function is essentially a phase‐matched measurement. At the same time, due to the amplitude independence of our proposed objective function, the subsequent weak reflections contribute with a similar weight to the total value of the misfit as the strong early reflections do. This makes it possible to recover the deep subsurface velocity. Synthetic data of the Sigsbee model and marine streamer field data applications validate that our amplitude‐independent reflection waveform inversion method can further improve the resolution and accuracy by aligning the reflection events of synthetic and observed data phase to phase without the need to perform true‐amplitude migration/demigration or least‐squares reverse time migration as in conventional reflection waveform inversion.

Individual timing consistency across long-distance songbird migrations.

Migration timing in long-distance migratory birds plays an essential role in individual survival and fitness and is thought to be driven by circannual routines cued by photoperiod with some plasticity to environmental conditions. We examined the individual order of migration timing in purple martins (Progne subis), a neotropical migratory songbird that travels between breeding sites throughout eastern North America and nonbreeding sites in Brazil. Migration timing data were collected for 295 different individual purple martins over 9 years using light-level geolocators deployed at breeding sites across the range. We used linear mixed-effect models to examine the influence of the rank order of individual departure dates in one season on the rank order of four subsequent migration events while controlling for the effects of breeding latitude, sex, and age. Overall, we found evidence for consistent individual timing that can extend across 8 months and 12,000-24,000 km of migration. Individual rank order of migration timing in purple martins was generally conserved across migrations with consistent timings between fall departure dates from, and spring arrival dates to the breeding site the following year (0.28 ± 0.03, 95% CI 0.22-0.34), as well as at a finer scale across fall migration (0.33 ± 0.05, 95% CI 0.23-0.43), over the stationary nonbreeding period (0.39 ± 0.04, 95% CI 0.31-0.47), and across spring migration (0.03 ± 0.001, 95% CI 0.028-0.032). These results demonstrate that purple martins exhibit consistency in individual migration timing throughout the annual cycle that is likely driven by inherent individual circannual schedules. We additionally found that migration distance played a significant role, as the consistency of individual timing lessened over longer distances. Understanding how individual birds time migrations and if individuals are consistent between events can provide insight into how birds respond to shifts in their environment with climate change.

Kinetic simulation of uranium migration in granite fissure media of beishan, gansu, China: A case study based on the Laplace transform and inverse transform methods

Deep geological disposal is currently considered the most practical and feasible method for disposing high-level radioactive wastes (HLWs). One of its key scientific issues is the migration of nuclides in fissure media. However, studies on the migration of nuclides like U-238 are relatively limited. In this study, the granite rock masses in Beishan, Gansu were selected to construct a physical and mathematical model of U-238 migration using the Laplace transform and inverse transform methods. Based on the numerical methods, the kinetic migration of nuclide U-238 in the fissure media of granite was simulated, and the effects of parameters such as fissure width, hydraulic gradient, diffusible area ratio and rock porosity on the migration of U-238 were investigated. The following insights were obtained: (1) After 100,000 years, U-238 has a very limited diffusion depth in the matrix domain, with a diffusion range of only a few tens of millimeters, whereas it migrates relatively quickly in the fissure domain, with a maximum migration distance of about 1500 m. (2) Under the same migration time and distance, the relative concentration of nuclide U-238 in the fissure domain increases with larger gap width, hydraulic gradient, and diffusible area ratio, but decreases with higher rock porosity. (3) In the same time range, the rock masses with larger gap widths, hydraulic gradients, and diffusible area ratios have larger migration ranges, while those with higher porosities have smaller migration ranges. (4) While selecting a site for diposal of HLWs, it is recommended to choose rock masses in the granite area of Beishan with no fissures or few fissures; additionally, areas with smaller fissure widths, hydraulic gradients, and diffusible area ratios but higher rock porosity should be prioritized. This study can provide important theoretical support for understanding nuclide migration in the future geological disposal of HLWs.

A Latecomer’s Advantage: The Attainments of Older Child Immigrants

Childhood immigrants arrive in the United States (U.S.) at different ages, each with a distinct set of skills. Previous research emphasizes the importance of early immigration in language acquisition and its subsequent effect on education and labor market outcomes. This study investigates whether migration timing has differential effects when considering other skills, specifically initial education quality. Using U.S. data of 322,328 childhood immigrants prior to 2018, we find that delayed childhood immigration from top-scoring countries in academic testing can mitigate the disadvantages associated with language acquisition. Our results suggest that children from topscoring, non-English-speaking countries appear to benefit most from later migration. Specifically, male immigrants gain an additional 2.57 years of U.S. education, while females gain 0.33 years. These additional years of education correspond to subsequent higher wages. Our study suggests a revaluation of policies, particularly regarding “late child immigrants” arriving from high-PISAscoring countries, as those individuals may achieve higher educational and income levels than previously anticipated.

Early-life variation in migration is subject to strong fluctuating survival selection in a partially migratory bird.

Population dynamic and eco-evolutionary responses to environmental variation and change fundamentally depend on combinations of within- and among-cohort variation in the phenotypic expression of key life-history traits, and on corresponding variation in selection on those traits. Specifically, in partially migratory populations, spatio-seasonal dynamics depend on the degree of adaptive phenotypic expression of seasonal migration versus residence, where more individuals migrate when selection favours migration. Opportunity for adaptive (or, conversely, maladaptive) expression could be particularly substantial in early life, through the initial development of migration versus residence. However, within- and among-cohort dynamics of early-life migration, and of associated survival selection, have not been quantified in any system, preventing any inference on adaptive early-life expression. Such analyses have been precluded because data on seasonal movements and survival of sufficient young individuals, across multiple cohorts, have not been collected. We undertook extensive year-round field resightings of 9359 colour-ringed juvenile European shags Gulosus aristotelis from 11 successive cohorts in a partially migratory population. We fitted Bayesian multi-state capture-mark-recapture models to quantify early-life variation in migration versus residence and associated survival across short temporal occasions through each cohort's first year from fledging, thereby quantifying the degree of adaptive phenotypic expression of migration within and across years. All cohorts were substantially partially migratory, but the degree and timing of migration varied considerably within and among cohorts. Episodes of strong survival selection on migration versus residence occurred both on short timeframes within years, and cumulatively across entire first years, generating instances of instantaneous and cumulative net selection that would be obscured at coarser temporal resolutions. Further, the magnitude and direction of selection varied among years, generating strong fluctuating survival selection on early-life migration across cohorts, as rarely evidenced in nature. Yet, the degree of migration did not strongly covary with the direction of selection, indicating limited early-life adaptive phenotypic expression. These results reveal how dynamic early-life expression of and selection on a key life-history trait, seasonal migration, can emerge across seasonal, annual, and multi-year timeframes, yet be substantially decoupled. This restricts the potential for adaptive phenotypic, microevolutionary, and population dynamic responses to changing seasonal environments.

Genetic Sex and Origin Identification Suggests Differential Migration of Male and Female Atlantic Bluefin Tuna (Thunnus thynnus) in the Northeast Atlantic

ABSTRACTKnowledge about sex‐specific difference in life‐history traits—like growth, mortality, or behavior—is of key importance for management and conservation as these parameters are essential for predictive modeling of population sustainability. We applied a newly developed molecular sex identification method, in combination with a SNP (single nucleotide polymorphism) panel for inferring the population of origin, for more than 300 large Atlantic bluefin tuna (ABFT) collected over several years from newly reclaimed feeding grounds in the Northeast Atlantic. The vast majority (95%) of individuals were genetically assigned to the eastern Atlantic population, which migrates between spawning grounds in the Mediterranean and feeding grounds in the Northeast Atlantic. We found a consistent pattern of a male bias among the eastern Atlantic individuals, with a 4‐year mean of 63% males (59%–65%). Males were most prominent within the smallest (< 230 cm) and largest (> 250 cm) length classes, while the sex ratio was close to 1:1 for intermediate sizes (230–250 cm). The results from this new, widely applicable, and noninvasive approach suggests differential occupancy or migration timing of ABFT males and females, which cannot be explained alone by sex‐specific differences in growth. Our findings are corroborated by previous traditional studies of sex ratios in dead ABFT from the Atlantic, the Mediterranean, and the Gulf of Mexico. In concert with observed differences in growth and mortality rates between the sexes, these findings should be recognized in order to sustainably manage the resource, maintain productivity, and conserve diversity within the species.

Source-independent Q-compensated viscoacoustic least-squares reverse time migration

The strong viscosity of the subsurface introduces amplitude absorption and phase-velocity dispersion. Incorrect compensation of the inherent attenuation (the strength of the seismic attenuation can be quantified by the inverse of the quality factor Q, which is defined as [Formula: see text] times the ratio of the stored energy to the lost energy in a single cycle of deformation) can significantly affect imaging quality. Although Q-least-squares reverse time migration ( Q-LSRTM) allows for the compensation of attenuation effects during the iterations, the traditional [Formula: see text]-norm minimization, which is highly sensitive to the source wavelet, poses a challenge in accurately estimating the source wavelet from the field data. Thus, we develop a source-independent Q-LSRTM, in which a convolutional objective function is introduced to replace the [Formula: see text]-norm constraint to mitigate the source wavelet effect. According to the Born approximation, we first linearize the constant-order decoupled fractional Laplacian viscoacoustic wave equation to derive the demigration operator and then construct the corresponding adjoint equation and gradient based on the convolutional objective function, iteratively estimating the reflectivity images. Our method relaxes the sensitivity to the wavelet compared with the conventional [Formula: see text]-norm scheme due to the convolutional objective function, which has the ability to construct the same new source for simulated and observed data. Numerical tests on a layered model, the Marmousi model, and field data demonstrate that our source-independent Q-LSRTM enables us to obtain high-quality reflectivity images even when using incorrect source wavelets.

The qP- and qSV-wave separation in 2D vertically transversely isotropic media and their applications in elastic reverse time migration

Compressional and shear wave separation is an important step in anisotropic elastic reverse time migration (ERTM). With separated wavefields, we can generate images between different wave types and reveal more subsurface physical properties, as well as remove unwanted crosstalk and improve image quality. Traditional Helmholtz decomposition based on divergence and curl operations for isotropic media cannot be directly extended to vertically transversely isotropic (VTI) media. Wave-mode separation methods, similar to the nonstationary spatial filter and Poynting vector, cannot preserve the phase and amplitude information of the original coupled wavefield, thus limiting their application in ERTM. Currently, the anisotropic wavefield decomposition methods include the wavenumber-domain approach, the low-rank approximation, and other separation approaches based on different approximations, e.g., weak or elliptical anisotropy. These methods are either computationally intensive or involve large separation errors, especially in models with strong heterogeneities and anisotropy. The VTI wavefield separation operator is essentially defined in a mixed space-wavenumber domain. We introduce scalar operators to transfer operations from this mixed space-wavenumber domain to the space domain. The local wave propagation direction in the scalar operators is estimated using the Poynting vector, which is highly computationally efficient in the space domain. When we apply the wave separation method to ERTM, we not only obtain the vectorized qP and qSV waves but also retrieve the scalar qP wavefield. The scalar and vector wavefields preserve the amplitude and phase information in the original coupled wavefield. For anisotropic ERTM, we suggest using the scalar imaging condition to generate the PP image and the magnitude- and sign-based vector imaging condition to produce the PS image, both having higher image accuracy than the dot-product imaging condition. Numerical examples are used to validate our anisotropic wavefield separation method and the related ERTM workflow.

A simple and efficient approach for preparing cationic coating with tunable electroosmotic flow for capillary zone electrophoresis-mass spectrometry-based top-down proteomics

BackgroundCapillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) has become a valuable analytical technique in top-down proteomics (TDP). CZE-MS/MS-based TDP typically employs separation capillaries with neutral coatings (i.e., linear polyacrylamide, LPA). However, issues related to separation resolution and reproducibility remain with the LPA-coated capillaries due to the unavoidable non-specific protein adsorption onto the capillary wall. Cationic coatings can be critical alternatives to LPA coating for CZE-MS/MS-based TDP due to the electrostatic repulsion between the positively charged capillary inner wall and proteoform molecules in the acidic separation buffer. Unfortunately, there are only very few studies using cationic coating-based CZE-MS/MS for TDP studies. ResultsIn this work, we aimed to develop a simple and efficient approach for preparing separation capillaries with a cationic coating, i.e., poly (acrylamide-co-(3-acrylamidopropyl) trimethylammonium chloride [PAMAPTAC]) for CZE-MS/MS-based TDP. The PAMAPTAC coating-based CZE-MS produced significantly better separation resolution of proteoforms compared to the traditionally used LPA-coated approach. It achieved reproducible separation and measurement of a simple proteoform mixture and a complex proteome sample (i.e., a yeast cell lysate) regarding migration time, proteoform intensity, and the number of proteoform identifications. The PAMAPTAC coating-based CZE-MS enabled the detection of large proteoforms (≥30 kDa) from the yeast cell lysate reproducibly without any size-based prefractionation. Interestingly, the mobility of proteoforms using the PAMAPTAC coating can be predicted accurately using a simple semi-empirical model. SignificanceThe results render the PAMAPTAC coating as a valuable alternative to the LPA coating to advance CZE-MS-based TDP towards high-resolution separation and highly reproducible measurement of proteoforms in complex samples.

Estuarine dams and weirs: Global analysis and synthesis

Estuarine dams and weirs are constructed in estuaries for reasons such as blocking the salt intrusion, securing freshwater, and stabilizing upstream water levels. While they can provide many social benefits, they can also alter estuarine physical and sedimentary processes. How this occurs and their relative importance to global estuaries and deltas are not well understood. To address this, we perform and extensive remote sensing and literature analysis. Remote sensing was conducted based on a global river database of 1531 rivers representing the largest rivers cumulatively draining 85 % of the landmass discharging into the global ocean. It was found that 9.7 % of global estuaries and deltas are currently affected by estuarine dams or weirs acting as the upstream limit of salt, tide, or storm surge intrusion. If we include supplementary examples, overall 220 estuaries with estuarine dams or weirs were identified and confirmed by literature review. These structures are found worldwide and are prominent in developed or developing countries in Asia, Europe, North America, and Oceania. The number of estuarine dams and weirs has increased rapidly since the 1800s with a peak in construction rate in the 1970s, particularly due to construction in Asia. Estuarine dams and weirs are found at the river mouths of both small and large watersheds. Most of these estuarine structures are located at x = 0–100 km inland from the mouth and their discharge intervals can be continuous, daily – weekly, seasonal, or interannual. Based on a quantified classification by geomorphology, estuarine dams and weirs are found most in river mouths which are wave-dominated followed by tide-dominated and then river-dominated. Estuarine dams and weirs can cause significant changes to the quantity and timing of freshwater discharge, tides, stratification, turbidity, sedimentation, oxygen conditions, phytoplankton blooms, and fish migration. We synthesize this current knowledge on estuarine dams and weirs and propose a conceptual model for physical and geomorphological change in mixed wave- and river-dominated and tide-dominated estuaries with estuarine dams.

Modelling the complete life cycle of an arctic copepod reveals complex trade-offs between concurrent life cycle strategies

Calanus hyperboreus is a large-bodied, biomass dominant species that performs a crucial ecosystem energy transfer by converting the spring phytoplankton bloom into lipid reserves that fuel the higher trophic levels of the Gulf of St. Lawrence (GSL) pelagic ecosystem, including the critically endangered North Atlantic right whale (Eubalena glacialis). Given that the GSL, the southernmost core habitat of C. hyperboreus, is undergoing rapid warming, developing a population model allows us to synthesize existing knowledge of the species, and to examine the species response to environmental conditions. To simulate the multi-year life cycle in the northwest GSL, model equations are implemented for ingestion, assimilation, respiration, egg production, stage development, mortality, and vertical migration behaviors including dormancy entry and exit. The 1-D particle-based model predicts the evolution of individual stage, structural mass, lipid, age, sex, abundance, and egg production, as well as the seasonal evolution of the population structure in the northwest GSL. Individual lipid-based thresholds inform the timing of ontogenetic vertical migration. Life cycle targets defined from a literature review are used to guide model parameterization and assess its performance. The simulated population structure, phenology, and size at stage are generally consistent with observations. Under 10 years of repeat year forcing, the model simulates a quasi-stable overwintering population composed of late stages CIV, CV and CVI. Observations suggest that stage CIV is the first overwintering stage in the GSL, and point to the occurrence of iteroparous females. Using the model, the relative success of diverse dormancy and reproductive phenotypes are explored. Second reproduction females reproduce earlier in winter than first reproduction females, with implications for the ability of the new generation to match the spring bloom and accumulate sufficient lipid to overwinter as stage CIV. Without iteroparity, the time window of reproduction contracts and the population is reduced, underscoring the role of a flexible multi-year life cycle in population success.

Elastic reverse time migration using an efficient and accurate adaptive variable grid discretization method

Abstract The conventional reverse time migration utilizes regularly sampled computational grids to simulate wave propagation. Selecting the appropriate grid sampling is important for computational accuracy and efficiency. In general, the uniform-size grid cannot represent the complexity of the geology well. The grid may appear sparse in the low-velocity zone, especially in shallow depths where dispersion may occur. Conversely, it may appear excessively dense in the high-velocity zone, such as at greater depths or within a salt body, which results in higher computational memory and time consumption. To overcome these issues, we developed an efficient and accurate adaptive variable grid discretization method that automatically selects the vertical grid size based on the velocity, depth, and dominant frequency of the wavelet in elastic medium. Then we reformulated the elastic equations based on the adaptive variable grid by introducing a mapping relationship. To test the effectiveness, accuracy, and efficiency of the equation, we implemented it to both the forward propagation and migration of elastic wavefield. Synthetic numerical examples demonstrate that our proposed method can achieve elastic wavefield separation and no significant dispersion phenomenon. The multi-component imaging accuracy of reverse time migration is nearly equivalent to the traditional method, while significantly improving computational efficiency and saving storage space.

Estimating the effects of smolt size and migration timing on salmon marine survival using a multivariate mixed‐effect model

Abstract When the conditions encountered by a migratory species are highly variable, the timing of migration and migrant condition are critical to survival. Spring/summer‐run Chinook salmon in the Snake River of the Northwestern United States are listed as threatened under the US Endangered Species Act because of decades of poor adult returns; juvenile smolt‐to‐adult survival is often 0.5% or less. Juveniles pass through eight dams en route to the ocean, and despite changes to the hydropower system, there has been little recent improvement in survival. We analysed the effect of migration date, fish length and their interaction on the survival to adulthood of 409,747 wild juvenile Chinook salmon as they migrated through a large, dynamic riverine ecosystem and through the ocean, measured over 20 years. Parametric 2D smoothers are often used to quantify unexplained heterogeneity across space; however, these same statistical models can be applied to 2D datasets to uncover patterns of covariance of two biological processes important to management actions. We employ Gaussian Markov random fields (GMRF) and a 2D smoother to estimates of fish survival to identify the nature of variation in survival with respect to length and date. We found significant effects of fish length, migration date and the date‐by‐length interaction on resulting riverine and marine survival. Unlike the gradual shifts in survival in relation to length and timing that marginal estimates demonstrate, we show that within year, changes in survival with length and timing are often more abrupt than previously thought. Synthesis and applications: Inter‐annually, we identified distinct combinations of fish length and migration timing leading to elevated smolt‐to‐adult survival. Often these ‘hotspots’ are compressed into fish sizes greater than 100 mm and passage timings of only a week or two, demonstrating that even modest shifts in body size and migration timing can have a significant effect on survival. Further research can concentrate on these distinct annual periods to identify sources of mortality that have previously been elusive.

Assessment of heavy metal diffusion rates from river Yamuna and its effect on the surrounding geology: An experimental and theoretical study

The present study for the first time quantitatively investigates the acute pollution of the Yamuna River, focusing on the diffusion of heavy metals from industrial effluents into groundwater, surrounding soils, and crops, and its subsequent impact on human health. Owing to the unplanned discharge of the untreated effluents, the river exhibits heavy metal concentrations exceeding Indian standards. Utilizing 1-D diffusion transport models, Heavy metal pollution indices (HPI), and transfer factor (TF) for two different locations, it was understood that diffusion is a dominant mechanism that allows the heavy metals from the river to pollute the surrounding geology. The HPI in the groundwater was more than 200 at the studied locations indicating severe contamination of the groundwater, moreover, the TF of the crops through the soil was more than unity for various heavy metals present, viz., Cr, Cu, Zn, Cd, and Hg. The estimated apparent diffusion coefficient (Da) was also found to be very high for these metals that lay in the range of 4.8 × 10−10 – 9.9 × 10−10 m2/s. The time necessary to migrate from the river to the crops was the least for Hg. The suitability of the crops for ingestion post-diffusion was further assessed by estimating the Daily Intake of Metals (DIM). The DIM reveals that the crops are highly unsuitable for children and adults as the values exceed the standard limits. Such a high migration rate of heavy metals from the river to the surrounding geology needs attenuation at the source to restrict migration. The evaluated apparent Da and migration times of heavy metals would provide critical insights for designing effective barrier systems to mitigate contamination.

Quantitative Analysis of Chondroitin Sulfate and Dermatan Sulfate Using Capillary Electrophoresis With Gaussian Distribution‐Based Peak Fitting for Improved Peak Resolution

ABSTRACTIn this work, capillary electrophoresis with Gaussian distribution‐based peak fitting for improved peak resolution for simultaneous quantitative analysis of chondroitin sulfate (CS) and dermatan sulfate (DS) was developed for the first time. The effects of different pH, voltage, and peak shapes on the peak fitting were investigated. The results indicate that separation conditions that affect peak shape have a significant impact on peak fitting. Under optimized separation conditions, the peak fitting achieves high accuracy and precision, the relative standard deviation (n = 5) of peak area and migration time of CS and DS were 1.1%, 1.8% and 0.94%, 0.84%, respectively. Furthermore, the results obtained by peak fitting were close to real values. The developed method was used to analyze the purity of CS. The results had a high consistency with the labeled value; furthermore, the peak fitting could point out the number of possible impurities. The developed method has good potential for the analysis of other glycosaminoglycans with peak overlap.

Target-oriented image-domain elastic least-squares reverse time migration

Elastic least-squares reverse time migration (ELSRTM), as an imaging method, offers advantages over conventional elastic reverse time migration (ERTM), including higher resolution, better amplitude balancing, reduced crosstalk, and broader bandwidth. However, conventional ELSRTM involves iterative processes in the data domain, resulting in high computational costs. Moreover, since time is continuous during data domain extrapolation, it cannot solely focus on the target area within the subsurface medium. In contrast, image-domain ELSRTM (IDELSRTM) exhibits high computational efficiency and the ability to image target area. Currently, research on image-domain least-squares reverse time migration is predominantly focused on the acoustic wave assumption, despite elastic waves being closer to the actual subsurface medium and providing richer imaging information. In this study, within the framework of data domain ELSRTM, we derived the objective function for the IDELSRTM and introduced an L1 regularization term under the L2 norm to enhance inversion stability. We devised an inversion strategy employing the fast iterative shrinkage-thresholding algorithm (FISTA). Furthermore, drawing from the point spread functions theory in optics, we derived the mapping relationship between the elastic multi-parameter point spread functions (PSF) and the elastic multi-parameter Hessian matrix, and the relationship between the Hessian matrix and the ERTM images. We provided the computational method for the elastic multi-parameter Hessian matrix and utilized it as the linearized forward operator for IDELSRTM. Through numerical experiments, we further elucidated the relationship between the ERTM images and the Hessian matrix under the framework of IDELSRTM, along with the sources of crosstalk in ERTM. Applying our proposed target-oriented IDELSRTM method to layered models and the Marmousi2 model, we demonstrated its effectiveness in improving imaging resolution and quality with only a marginal increase in computational overhead compared to conventional ERTM.

Temperature and time of season are the predominant drivers of cabbage stem flea beetle, Psylliodes chrysocephala, arrival at oilseed rape crops

Cabbage stem flea beetle (CSFB) is an economically important pest of oilseed rape crops responsible for substantial yield losses in recent years, particularly since the restrictions on neonicotinoid seed treatment use came into force in 2013. To effectively time sowing dates and target control measures, it is crucial that accurate estimates of when migratory adult CSFB will arrive at the crop can be made. A Bayesian hierarchical model was fitted to data from 19 sites containing adult CSFB traps over a period of three years to characterise the relationship between the day of year, temperature, rainfall, wind speed and solar radiation on beetle counts and to understand their relative importance. Day of the year was identified as the main driver of migration and temperature was the predominant environmental driver of CSFB migration. A hot day (based on the range of observed temperatures over the trapping window) resulted in approximately 300% of the expected CSFB migration relative to an average day during peak migration. The second most important environmental driver of migration was wind speed, but this resulted in a relatively negligible increase of approximately 15% from an average day to a still day. These findings suggest that efforts to predict timing of adult CSFB migration should focus on understanding how the phenology of CSFB and temperature interact to drive the timing of migration.

The impact of parental migration patterns, timing, and duration on the health of rural Chinese children.

Parent-child separation raises concerns for the well-being of 69 million left-behind children (LBC) in China. However, the effects of parental migration status, timing of migration, and migration duration on the health of children remain unclear. This study aims to explore the association between different parent-child separation experience and a range of health outcomes in rural Chinese children. A sample of 2,355 students, grades 5 to 8, from two provinces in China were recruited. Standardized self-report instruments collected data on demographics, separation status, and children's health conditions. Full data were available for 274 children with both parents currently migrating (BLBC), 638 children with one parent currently migrating (SLBC), 658 children with parents previously migrated (PLBC) and 785 children with non-migrating parents (NLBC). Regression model results showed that, compared to the NLBC group, BLBC and PLBC exhibited lower self-rated health (p < 0.05), higher depression (p < 0.05), and higher rates of non-suicidal self-injury behaviors (p < 0.05) and suicidal ideation (p < 0.05). Children who experienced parental separation before the age of three were at a higher risk for four health indicators. Additionally, children left behind by parents for more than 7 years had significantly worse health outcomes. Children who have experienced both current and previous parental migration, as well as earlier parental migration age and longer migration duration, are at a disadvantage in terms of health. These findings highlight the need for targeted interventions focusing on the most vulnerable children.

Development of cyclodextrin-electrokinetic chromatography-based strategies for the separation of ketorolac enantiomers

The development of analytical strategies enabling the chiral separation of ketorolac by electrokinetic chromatography is presented in this work. This anti-inflammatory drug is commercialised as racemic mixture but its physiological activity resides in the S-enantiomer. Different experimental conditions were investigated at acidic and neutral pH, including the use of cyclodextrins (CD) or amino acid-based ionic liquids (AAILs) ([TMA][L-Cit], [TMA][L-Arg], [TMA][L-Harg], [TBA][L-Cit], [TBA][L-Arg], and [TBA][L-Harg]) as the sole chiral selectors or the combination of a CD with AAILs or their cationic components (tetramethylammonium (TMA-OH) or tetrabutylammonium (TBA-OH)). The best conditions in terms of migration times and enantiomeric resolutions were obtained using 2 mM heptakis(2,3,6-tri-O-methyl)-β-CD (TM-β-CD) in 50 mM phosphate buffer at pH 7.0 or 2 mM TM-β-CD with 60 mM TMA-OH in 50 mM formate buffer at pH 3.0. The presence of TMA-OH in the separation medium affected considerably the electroosmotic flow (EOF) mobility which, in turn, significantly shortened the migration times for ketorolac enantiomers at pH 3.0 due to an inversion in the EOF. The multivariate optimization of the experimental conditions for the single system and for the combined system with TMA-OH enabled to obtain the separation of ketorolac enantiomers in less than 11 min with enantiomeric resolutions of 2.5 and 1.9, respectively. The single system was selected to evaluate its analytical characteristics in terms of limits of detection/quantification, accuracy, and precision, according to the International Council for Harmonization (ICH) guidelines, which resulted adequate to be applied to the analysis of pharmaceutical formulations.