Patterns Of Variation Research Articles

A national-scale assessment on the spatial and temporal variations in water color for urban lakes in China

Monitoring the variations of lake water quality is essential for urban water security and sustainable eco-environment health. However, it is challenging to investigate the water quality of urban lakes at large scales due to the need for large-amount in situ data with diverse optical properties for developing the remote sensing inversion algorithms. Forel-Ule Index (FUI), a proxy of quantifying water color, whose calculation does not require in situ data of specific properties, can comprehensively reflect water quality conditions. However, the spatial and temporal distribution of water color in Chinese urban lakes is still poorly understood. To fill this research gap, this study investigated the spatial distribution of water color in 523 urban lakes (area > 0.5 km2) in China using the FUI derived from the high-quality Multi-Spectral Instrument (MSI) data onboard Sentinel-2 during the ice-free period (April–October) from 2019 to 2022. The monthly and seasonal variation patterns of water color in urban lakes were also analyzed. Our results show that green domain is the most common color of urban lakes, with about 86 % of urban lakes in China being green, and non-green lakes accounting for only 14 % of the total number of lakes. The monthly variation of FUI in urban lakes across the country and multiple geographic regions is basically the same. The monthly average FUI first increases, then decreases, and then rebounds. We also found that the seasonal variation of water color in most urban lakes in southern and northern China is opposite. This study helps to comprehensively understand the spatial and temporal variation of water color and quality of urban lakes in China, providing key basic information for the protection and governance of urban lakes.

A comparative anatomical network analysis of the human and chimpanzee brains.

Spatial interactions among anatomical elements help to identify topological factors behind morphological variation and can be investigated through network analysis. Here, a whole-brain network model of the chimpanzee (Pan troglodytes, Blumenbach 1776) is presented, based on macroanatomical divisions, and compared with a previous equivalent model of the human brain. The goal was to contrast which regions are essential in the geometric balance of the brains of the two species, to compare underlying phenotypic patterns of spatial variation, and to understand how these patterns might have influenced the evolution of human brain morphology. The human and chimpanzee brains share morphologically complex inferior-medial regions and a topological organization that matches the spatial constraints exerted by the surrounding braincase. These shared topological features are interesting because they can be traced back to the Chimpanzee-Human Last Common Ancestor, 7-10 million years ago. Nevertheless, some key differences are found in the human and chimpanzee brains. In humans, the temporal lobe, particularly its deep and medial limbic aspect (the parahippocampal gyrus), is a crucial node for topological complexity. Meanwhile, in chimpanzees, the cerebellum is, in this sense, more embedded in an intricate spatial position. This information helps to interpret brain macroanatomical change in fossil hominids.

Windbreak and sand fixation service flow simulation in the terminal lake basin of inland rivers in arid regions: A case study of the Aral Sea basin

Research on windbreak and sand fixation (WSF) services aids in soil conservation, and ecological protection. Over the past 50 years, the Aral Sea's shrinkage has intensified wind erosion, leading to significant sand and dust emissions in Central Asia (CA). This study uses the Revised wind erosion equation (RWEQ) model and the hybrid single particle Lagrangian integrated trajectory model (HYSPLIT) model to simulate the spatiotemporal variation pattern of WSF services in the Aral Sea basin (ASB). From the perspective of sand and dust transmission paths, the flow trajectory and benefit areas of WSF services are identified, the spatiotemporal correlation between the WSF service supply areas and benefit areas is established, and the potential impact of WSF services on beneficiary areas is quantitatively assessed. The results show the amount of wind erosion and the amount of WSF in the ASB from 2000 to 2019 showed a fluctuating trend of “first increasing and then decreasing”. In terms of spatial distribution, areas with large amounts of WSF are mainly distributed in the lower reaches of the Syr Darya River and the sand dunes in the northwest of the Kizilkum Desert. WSF services mainly flow through the Kizilkum Desert, Karakum Desert, Moyinkum Desert, Kazakh Hills, and the Junggar Basin and Tarim Basin in China. Generally, it flows to the northeast and southwest. In the past 20 years, the largest areas benefiting from the flow of WSF services are mainly distributed in Uzbekistan, Kyrgyzstan, and Tajikistan. The trajectory distribution frequency shows a decreasing trend from the center to the periphery. The grassland areas constituted the largest beneficiary areas in the ASB of CA, with both the beneficiary population and real GDP exhibiting an upward trend. This study holds significant importance for enhancing the management of ecosystem services in sandy regions and for establishing ecological compensation mechanisms.

The Use of the GWPCA-MGWR Model for Studying Spatial Relationships between Environmental Variables and Longline Catches of Yellowfin Tunas

The yellowfin tuna represents a significant fishery resource in the Pacific Ocean. Its resource endowment status and spatial variation mechanisms are intricately influenced by marine environments, particularly under varying climate events. Consequently, investigating the spatial variation patterns of dominant environmental factors under diverse climate conditions, and understanding the response of yellowfin tuna catch volume based on the spatial heterogeneity among these environmental factors, presents a formidable challenge. This paper utilizes comprehensive 5°×5° yellowfin tuna longline fishing data and environmental data, including seawater temperature and salinity, published by the Western and Central Pacific Fisheries Commission (WCPFC) and the Inter-American Tropical Tuna Commission (IATTC) for the period 2000–2021 in the Pacific Ocean. In conjunction with the Niño index, a multiscale geographically weighted regression model based on geographically weighted principal component analysis (GWPCA-MGWR) and spatial association between zones (SABZ) is employed for this study. The results indicate the following: (1) The spatial distribution of dominant environmental factors affecting the catch of Pacific yellowfin tuna is primarily divided into two types: seawater temperature dominates in the western Pacific Ocean, while salinity dominates in the eastern Pacific Ocean. When El Niño occurs, the area with seawater temperature as the dominant environmental factor in the western Pacific Ocean further extends eastward, and the water layers where the dominant environmental factors are located develop to deeper depths; when La Niña occurs, there is a clear westward expansion in the area with seawater salinity as the dominant factor in the eastern Pacific Ocean. This change in the spatial distribution pattern of dominant factors is closely related to the movement of the position of the warm pool and cold tongue under ENSO events. (2) The areas with a higher catch of Pacific yellowfin tuna are spatially associated with the dominant environmental factor of mid-deep seawater temperature (105–155 m temperature) to a greater extent than other factors, the highest correlation exceeds 70%, and remain relatively stable under different ENSO events. The formation of this spatial association pattern is related to the vertical movement of yellowfin tuna as affected by subsurface seawater temperature. (3) The GWPCA-MGWR model can fully capture the differences in environmental variability among subregions in the Pacific Ocean under different climatic backgrounds, intuitively reflect the changing areas and influencing boundaries from a macro perspective, and has a relatively accurate prediction on the trend of yellowfin tuna catch in the Pacific Ocean.

Release of perfluoroalkyl acids from sediments under the effects of the discharge ratio and flow flux at a Y-shaped confluence

The sediments in riverine environments contain notably high concentrations of perfluoroalkyl acids (PFAAs), which may be released into the water body under different hydrodynamic forces, such as those occurring at Y-shaped confluences. The release of PFAAs may pose a significant risk to the surrounding aquatic ecosystems. However, our understanding of the release and transport of PFAAs from sediments at Y-shaped confluences remains unclear. Thus, in this study, we performed a series of flume experiments to explore the effects of discharge ratio and total flow flux on the release and redistribution of PFAAs. The results indicated that these two parameters significantly affected the hydrodynamic features of confluences and the water physicochemical parameters. PFAA concentrations in the dissolved phase and suspended particulate matter (SPM) rose significantly as the discharge ratio and total flow flux increased. The dissolved phase was the predominant loading form of PFAAs, with short-chain PFAAs being the main kind, while long-chain PFAAs were dominant in the SPM. The spatial distribution pattern of PFAAs in sediments at the confluence exhibited a high degree of correspondence with hydrodynamic zones. The separation zone and maximum velocity zone were consistent with sediment regions with low and high capacities to release PFAAs, respectively. The patterns of variation in PFAA distribution were comparable to those observed in hydrodynamic zones as the discharge ratio and total flow flux varied. Furthermore, these two parameters altered the partitioning behaviors of PFAAs; specifically, the PFAAs in sediments tended to be released into the pore-water, while the liberated PFAAs tended to attach to SPM. Linear regression and correlation analyses suggested that the stream-wise and vertical flow velocity components near the sediment-water interface were the primary contributors to sediment suspension and PFAA exchange between the water column and pore-water. These findings will help us to understand the patterns of PFAA release in sediments at Y-shaped confluences and assist in the management of PFAA-contaminated sediments at these locations.

Wavefront Changes during a Sustained Reading Task in Presbyopic Eyes.

The objective of this study was to assess the effect of sustained reading on the temporal changes in the wavefront error in the presbyopic eye. The wavefront aberration of the eyes was measured using an IRX3 Shack-Hartmann aberrometer before and after (immediately, 5 min, and 10 min after) a reading task. Temporal changes in C20, C40, and C3-1 coefficient values of the eyes were plotted, showing a predominant number of V-shaped patterns (for C40 and C3-1) and inverse V-shaped patterns (for C20) among the study group, and the percentages (between 27 and 73%) were reported. The median of the total RMS of aberrations and the RMS of HOA (higher-order aberrations), which included comatic (3rd order) and spherical-like aberrations (4th and 6th order), increased immediately after finishing the near-vision reading task and then decreased. The median of RMS of comatic aberrations had a similar pattern of variations, while the median of RMS of spherical-like aberrations displayed an opposite pattern. Simulating the aberration changes due to lens decentration caused by relaxed zonules during 4 D accommodation in an eye model demonstrated that the expected range of changes for the vertical coma and spherical aberrations are in the order of 0.001 and 0.01 μm, respectively, which could justify why the observed changes were not statistically significant. The observed dynamic changes in HOA might be linked to the biomechanical characteristics and alterations in the displacement of the crystalline lens following prolonged near-vision tasks in presbyopic people. Although some predominant patterns under some conditions were shown, they exhibit considerable inter-subject and inter-ocular variability. This might be due to slight misalignments while fixating on the internal extended object in the aberrometer.

Online model of wellness value for terminal difference of high-pressure heater targeting status diagnosis

Generally, health level of high pressure heater (HPH) for coal fired unit (CFU) can be diagnosed with wellness value of terminal temperature difference (TTD, upper end difference) compared with site measured value. However, TTD wellness value for HPH is tremendously involved by CFU boundary parameters. Simultaneously influencing mechanism is extremely complex. Such factor has been proven to make it laborious to accurately determine TTD wellness value in real-time during operation. Regretfully, up to now, a deficiency of theoretical methods for TTD wellness value on influence of unit boundary conditions is still subsistent. Under helplessness, TTD design value of HPH is roughly recognized as an imaginary wellness value for operators. Unfortunately, such ludicrous manipulating has brought stupendous errors to diagnosis of HPH faults.In this background, primarily calculation model for wellness of operating end difference of HPH is established on influence of boiler boundary conditions. Formidable coupling for boiler and turbine is cracked in model. Meanwhile, redistribution mechanism of heat transfer area for superheated condensation zone in HPH is firstly involved under variable conditions. Subsequently, variation pattern of main steam parameters and HPH extraction parameters were investigated on boundary parameters of boiler. Impact of such changing transmitted to HPH is captured. Therefore, influential mechanism from boiler boundary parameters on TTD health value of HPH was obtained. Exploration results indicate, a 1000 kJ/kg increment in coal calorific value as main influencing factor maximally dedicates 4 °C enhancement in TTD for HPH. Finally, diagnostic case of wellness status of HPH is provided. Proposed model can be employed to determine wellness value of HPH terminal difference in real-time online targeting changing in boundary conditions of CFU. The current situation of adopting design values of TTD as wellness values has been smashed. This research work, reputed as a fantastic theoretical foundation, make performance diagnosis of HPH a possibility especially real-time online diagnosis.

The diversity and risk of potential pathogenic bacteria on the surface of glaciers in the southeastern Tibetan Plateau

Glaciers, which constitute the world's largest global freshwater reservoir, are also natural microbial repositories. The frequent pandemic in recent years underscored the potential biosafety risks associated with the release of microorganisms from the accelerated melting of glaciers due to global warming. However, the characteristics of pathogenic microorganisms in glaciers are not well understood. The glacier surface is the primary area where glacier melting occurs that is often the main subject of research on the dynamics of pathogenic microbial communities in efforts to assess glacier biosafety risks and devise preventive measures. In this study, high-throughput sequencing and quantitative polymerase chain reaction methods were employed in analyses of the composition and quantities of potential pathogenic bacteria on the surfaces of glaciers in the southeastern Tibetan Plateau. The study identified 441 potential pathogenic species ranging from 215 to 4.39 × 1011 copies/g, with notable seasonal and environmental variations being found in the composition and quantity of potential pathogens. The highest level of diversity was observed in April and snow, while the highest quantities were observed in October and cryoconite. Host analysis revealed that >70 % of the species were pathogens affecting animals, with the highest proportion of zoonotic pathogens being observed in April. Analysis of aerosols and glacial meltwater dispersion suggested that these microbes originated from West Asia, primarily affecting the central and southern regions of China. Null model analysis indicated that the assembly of potential pathogenic microbial communities on glacier surfaces was largely governed by deterministic processes. In conclusion, potential pathogenic bacteria on glacier surfaces mainly originated from the snow and exhibited significant temporal and spatial variation patterns. These findings can be used to enhance researchers' ability to predict potential biosafety risks associated with pathogenic bacteria in glaciers and to prevent their negative impact on populations and ecological systems.

Genesis of the Jiada pegmatite lithium deposit in the Ke’eryin ore field, western Sichuan, China: Evidence from whole-rock trace element and Li isotope

The origin and petrogenesis of pegmatite-type lithium deposits within the Songpan-Garze Fold Belt (SGFB) of western China remain subjects of debate. To provide further insight on this subject, this study investigated the whole-rock trace elements and whole-rock Li isotopic compositions of the two-mica monzogranite (TMG) from the Ke’eryin composite pluton, the Jiada albite pegmatite (AP) and albite-spodumene pegmatite (ASP) and their metasedimentary wall rocks within the Ke’eryin ore field in the eastern SGFB. Modeling of muscovite-dehydration melting based on the whole-rock trace elements (e.g., Li, Rb, and Sr) and Rayleigh dehydration modeling related to the whole-rock Li isotopes suggest that the Jiada pegmatites are unlikely to have originated from the low-degree partial melting of metasandstone (MS) of the Zhuwo Formation. Variations in the whole-rock trace elements and Li isotope between the TMG and the Jiada pegmatites are consistent with the evolution trend of magmatic fractionation. However, the whole-rock Li isotopic compositions of the AP and ASP display inverse variation characteristics with the muscovite Li isotopic compositions, with the AP exhibiting lower Li concentrations and higher whole-rock δ7Li values than ASP. Furthermore, the variation patterns of whole-rock trace elements do not align perfectly with the Rayleigh-type fractional crystallization processes, implying other geological processes would be also involved in the formation of the Jiada pegmatites. Collectively considering the Li isotope behavior during various geological processes, the observed variations in whole-rock Li isotopic compositions between AP and ASP can be explained by aqueous fluid enrichment during the pegmatitic melt evolution. This suggests that fractional crystallization and fluid exsolution jointly contributed to pegmatite formation and Li mineralization in the Jiada deposit. Moreover, the whole-rock δ7Li values of the wall rock of ASP (MS2) are lower than those of MS and the wall rock of ASP (MS1), primarily due to metasomatism by 6Li-enriched fluids expelled from ASP and the kinetic diffusion of Li isotopes. The high concentrations of highly mobile elements, especially Li and Cs, combined with the low whole-rock δ7Li value of the metasandstone, could serve as effective tracers for locating concealed orebodies and evaluating the metallogenic potential of Li mineralization.

Numerical study on dynamic response of double drive shafts of dual-coupled axial piston pump under various load ratios

The dynamic response of the double drive shafts, as the core component of the dual-coupled axial piston pump, affects the stability and reliability of the pump. The double drive shafts bear complex dynamic loads accompanied by a certain degree of vibration during the transmission of power, which results in abnormal contact between the double drive shafts and the bearing, as well as between it and the splined coupler, leading to increased wear. In this study, addressing the fatigue failure issue of the double drive shafts in the dual-coupled axial piston pump, a rigid-flexible coupling dynamic model of the dual-coupled axial piston pump is established. The stress and strain conditions of the double drive shafts under various load ratios are analysed, along with the dynamic characteristics between the drive shaft and the barrel block, as well as between it and the spline sleeve in both time and frequency domains, and the variation pattern of the vibration displacement of the double drive shafts. Additionally, the fatigue damage of the double drive shafts under various load ratios is analysed using the fatigue cumulative damage model. The results show that under various load ratios, obvious stress and strain concentrations occur in the neck near the bearing connection and the spline sleeve connection. The safety factor of the double drive shafts is higher than 1.5 in the obtained safety load range. The contact force between the double drive shafts and the barrel block is mainly influenced by the reciprocating motion of the pistons, while the contact force between the double drive shafts and the spline sleeve is affected by the synergistic effect of the reciprocating motion of the piston and the rotation of the drive shaft. Furthermore, the increase in the rear pump load pressure results in irregular trends in the vibration displacement of the double drive shafts, as well as superimposed fatigue damage to the front shaft. This study provides a reference for fatigue failure prevention, noise reduction, and vibration damping of the double drive shafts under various load ratios.

Tau follows principal axes of functional and structural brain organization in Alzheimer’s disease

Alzheimer’s disease (AD) is a brain network disorder where pathological proteins accumulate through networks and drive cognitive decline. Yet, the role of network connectivity in facilitating this accumulation remains unclear. Using in-vivo multimodal imaging, we show that the distribution of tau and reactive microglia in humans follows spatial patterns of connectivity variation, the so-called gradients of brain organization. Notably, less distinct connectivity patterns (“gradient contraction”) are associated with cognitive decline in regions with greater tau, suggesting an interaction between reduced network differentiation and tau on cognition. Furthermore, by modeling tau in subject-specific gradient space, we demonstrate that tau accumulation in the frontoparietal and temporo-occipital cortices is associated with greater baseline tau within their functionally and structurally connected hubs, respectively. Our work unveils a role for both functional and structural brain organization in pathology accumulation in AD, and supports subject-specific gradient space as a promising tool to map disease progression.

Simulation Study on Temperature Control Performance of Lithium-Ion Battery Fires by Fine Water Mist in Energy Storage Stations.

The combustion of lithium-ion batteries is characterized by fast ignition, prolonged duration, high combustion temperature, release of significant energy, and generation of a large number of toxic gases. Fine water mist has characteristics such as a high fire extinguishing efficiency and environmental friendliness. In order to thoroughly investigate the temperature control effect of fine water mist on lithium-ion battery fires. This study employs numerical simulation methods, utilizing PyroSim software to simulate the fire process in lithium-ion battery energy storage compartments. First, we focus on the variation patterns of flame, changes in combustion temperature, and heat release rate over time at environmental temperatures of 10, 25, and 35 °C. Subsequently, the suppression of flame, reduction in temperature, and changes in heat release rate are simulated for water mist in lithium-ion battery fires. The simulation results indicate that the environmental temperature has a considerable impact on the flame but a lesser effect on the heat release rate. Fine water mist effectively impedes the spread of thermal runaway between internal battery core cells, leading to a reduction in the flame size and a significant decrease in the maximum temperature and heat release rate. The numerical simulation results can provide scientific guidance for the prevention and control of fires in lithium-ion battery energy storage compartments.

Genetic variation in recalcitrant repetitive regions of the Drosophila melanogaster genome.

Many essential functions of organisms are encoded in highly repetitive genomic regions, including histones involved in DNA packaging, centromeres that are core components of chromosome segregation, ribosomal RNA comprising the protein translation machinery, telomeres that ensure chromosome integrity, piRNA clusters encoding host defenses against selfish elements, and virtually the entire Y chromosome. These regions, formed by highly similar tandem arrays, pose significant challenges for experimental and informatic study, impeding sequence-level descriptions essential for understanding genetic variation. Here, we report the assembly and variation analysis of such repetitive regions in Drosophila melanogaster, offering significant improvements to the existing community reference assembly. Our work successfully recovers previously elusive segments, including complete reconstructions of the histone locus and the pericentric heterochromatin of the X chromosome, spanning the Stellate locus to the distal flank of the rDNA cluster. To infer structural changes in these regions where alignments are often not practicable, we introduce landmark anchors based on unique variants that are putatively orthologous. These regions display considerable structural variation between different D. melanogaster strains, exhibiting differences in copy number and organization of homologous repeat units between haplotypes. In the histone cluster, although we observe minimal genetic exchange indicative of crossing over, the variation patterns suggest mechanisms such as unequal sister chromatid exchange. We also examine the prevalence and scale of concerted evolution in the histone and Stellate clusters and discuss the mechanisms underlying these observed patterns.

The minimal important change is not a universal fixed value across diagnoses when using the FAOS and FAAM in patients undergoing elective foot and ankle surgery.

This study aimed to calculate region and diagnosis-specific minimal important changes (MICs) of the Foot and Ankle Outcome Score (FAOS) and the Foot and Ankle Ability Measure (FAAM) in patients requiring foot and ankle surgery and to assess their variability across different foot and ankle diagnoses. The study used routinely collected data from patients undergoing elective foot and ankle surgery. Patients had been invited to complete the FAOS and FAAM preoperatively and at 3-6 months after surgery, along with two anchor questions encompassing change in pain and daily function. Patients were categorised according to region of pathology and subsequent diagnoses. MICs were calculated using predictive modelling (MICPRED) and receiver operating characteristic curve (MICROC) method and evaluated according to strict credibility criteria. Substantial variability of the MICs between forefoot and ankle/hindfoot region was observed, as well as amongspecific foot and ankle diagnoses, with MICPRED and MICROC values ranging from 7.8 to 25.5 pointsand 9.4 to 27.8, respectively. Despite differences between MICROC and MICPRED estimates, both calculation methods exhibited largely consistent patterns of variation across subgroups, with forefoot conditions systematically showing smaller MICs than ankle/hindfoot conditions. Most MICs demonstrated high credibility; however, the majority of the MICs for the FAOS symptoms subscale and forefoot conditions exhibited insufficient or low credibility. The MICs of the FAOS and FAAM vary across foot and ankle diagnoses in patients undergoing elective foot and ankle surgery and should not be used as a universal fixed value, but recognised as contextual parameters. This can help clinicians and researchers in more accurate interpretation of the FAOS and FAAM change scores. Level IV.

Fluvial Dynamics and Hydrological Variability in the Chiriquí Viejo River Basin, Panama: An Assessment of Hydro-Social Sustainability through Advanced Hydrometric Indexes

The objective of this study was to conduct a detailed analysis of the available flow series in the Chiriquí Viejo River basin in Panama. This paper examines the patterns of variation within these series and calculates various hydrological indexes indicative of the region’s hydrology. Utilizing advanced hydrological indexes within the Chiriquí Viejo River basin in Panama, which spans an area of 1376 km2 and supports an estimated population of 100,000 inhabitants, analytical methods were employed to compute indexes such as the Daily Flow Variation Index (QVAR), the Slope of the Flow Duration Curve (R2FDC), the Hydrological Regulation Index (IRH), and the average duration of low (DLQ75) and high (DHQ25) flow pulses. The results indicate moderate flow variability (QVAR of 0.72) and a Hydrological Regulation Index (IRH) of 2.32, signifying a moderate capacity for flow regulation. Notably, low flow events (DLQ75) lasted approximately 3.73 days, while high flow events (DHQ25) lasted around 4.08 days. The study highlights a significant capacity to respond to extreme events, with maximum annual flows reaching 80.25 m3/s and minimum flows dropping to 3.01 m3/s. Despite the significant contribution of the basin to hydroelectric power generation and other economic activities, there is an observed need for sustainable management that accommodates hydrological fluctuations and promotes resource conservation. The conclusions indicate that these findings are critical for future planning and conservation strategies in the region, emphasizing the importance of integrating multidisciplinary approaches for Hydro-Social Sustainability. This novel and holistic approach underscores the interdependence between hydrological dynamics, socio-economic activities, and environmental sustainability, aiming to ensure the long-term resilience of the Chiriquí Viejo basin and its communities.

Weather conditions at different spatial and temporal scales influence avian post‐breeding migration patterns on route

AbstractMigration plays a central role in many ecological and evolutionary processes. Global patterns of climatic variation are having a profound influence upon animal migration patterns. Even though regular counts of bird migrations at bottleneck sites can certainly offer insights into how natural populations of different species at different scales are responding to changes in weather conditions, they have not yet been widely used. By analysing a time series of regular counts, collected during autumn, of 126 species migrating during the daytime through one of the most important migratory bottlenecks in Western Europe, we found that an increase in temperature at the regional scale, as well as a decrease in precipitation level during the breeding period, may result not only in a decrease in the migration rate during autumn but also in a delay in the timing of fall migration. Furthermore, adverse weather conditions at the local scale interrupted bird migration through the bottleneck until favourable weather conditions returned. Importantly, temporal variation in the number of migratory birds followed a nonlinear pattern, something which might be partially due to the idiosyncratic responses of migratory species with different life‐history characteristics to changes in weather conditions. Our results highlight that migration is a nonlinear, multiscale and multi‐faceted process, suggesting that it will be difficult to predict the responses of idiosyncratic migratory species to the unpredictable effects of climate change.

Revisiting Molossus (Mammalia: Chiroptera: Molossidae) diversity: Exploring southern limits and revealing a novel species in Argentina

Abstract Understanding species diversity and delineating their boundaries are crucial for effective management and conservation efforts. In the case of bats, species identification holds particular importance from an epidemiological standpoint. The genus Molossus (Chiroptera: Molossidae) encompasses 15 species distributed across the Neotropics, ranging from the southeastern United States to Argentina. This genus exhibits two contrasting patterns of variation: some species are cryptic, while others are morphologically distinct yet genetically similar. This study explores the diversity of Molossus in Argentina through a molecular phylogenetic approach. We analyzed sequences from three molecular markers (cyt b, COI, and FGB) along with morphology data obtained from a sample of 64 individuals. Uni- and multivariate analyses of external and cranial measurements were conducted, alongside comparisons of external and cranial characteristics among species. Based on molecular and morphological differences, we describe a new species within the Molossus genus. This newly discovered species exhibits a broad distribution spanning the Paraná River basin across three distinct ecoregions. It is noteworthy that this species is pseudo-cryptic with respect to similar-sized species such as M. molossus and M. melini. Additionally, it is important to mention that all species in Argentina have overlapping distribution ranges. In summary, this study provides valuable insights into the diversity and distribution of Molossus bats in Argentina, employing molecular and morphological analyses. The discovery of a new species underscores the ongoing importance of comprehensive research efforts in understanding and conserving bat populations in the Neotropics.

A Novel Hyperspectral Salt Assessment Model for Weathering in Architectural Ruins

Abstract. The Dunhuang murals, a significant part of Chinese heritage, have suffered deterioration primarily due to environmental and chemical factors, notably salt damage. This study proposes a sophisticated method that synergizes Fractional Order Differentiation (FOD) and Partial Least Squares Regression (PLSR) to accurately invert the phosphate content in the Mural Plaster of the Dunhuang paintings. The focal points of the research include: 1) To address the issue of information loss and reduced modeling precision caused by integer order differentiation algorithms, the FOD method is employed for preprocessing hyperspectral data. This approach ensures the fine spectral differences in the phosphate content of the Mural Plaster are precisely captured, 2) Utilizing PLSR, the study models the spectral bands identified at a significance level of 0.01 with measured conductivity values, thereby enabling the precise prediction of the phosphate content in the murals. The research outcomes reveal: 1) The FOD method can elucidate the nonlinear characteristics and variation patterns of the mural samples in the hyperspectral curve.As the order increases from zero to two, the number of spectral bands meeting the 0.01 significance test initially decreases and then increases. The highest absolute value of the positive correlation coefficient is observed at 1.9 orders, corresponding to the 2077 nm band, 2) For predicting the phosphate content in the murals, the model at 1.9 orders is most suitable for inversion. This model, after cross-validation, achieves a maximum R2 value of 0.783. This study created an efficient FOD-based model for estimating phosphate in mural plasters.

Numerical simulation of flow characteristics in nonprismatic compound channels

ABSTRACT The assessment of the flow characteristics of river systems is a very intricate undertaking in the development of hydraulic models for the purposes of flood control and floodplain management. Therefore, it is essential to use simulation models in order to calibrate and verify the experimental results. In this study, the Hydrologic Engineering Centre's – River Analysis System (HEC-RAS) is used to calibrate and validate the distribution of velocity and shear stress for different converging compound channels. Two separate flow regimes were assessed for validation based on experimental data obtained from converging compound channels with angles of θ = 5°, 9°, and 12.38°. The projected values for two relative depths (β = 0.15 and 0.20) exhibit a similar pattern of variation as the empirical observations and are marginally lower than the recorded values. This suggests that the HEC-RAS model accurately estimates the velocity and shear stress values. The disparity between the simulated and experimental outcomes shows a discrepancy of less than 10%. Hence, the implications of our results suggest that while dealing with nonprismatic rivers, it is advisable to take into account lower values. The used methodology and the outcomes focused on problem-solving might potentially inform the development of flood control infrastructure for nonprismatic watercourses.

Changes in secondary sexual characteristics of female red swamp crayfish (Procambarus clarkii) and relationship to ovarian development: Implications for intensive breeding of seedlings

A rapid selection method of mature Procambarus clarkii females for use in intensive breeding of seedlings is proposed based on evaluation of secondary sexual characteristics and variation patterns in this study. Following regular sampling in ponds, the weight, cephalothorax length, annulus ventralis length, body width, white patch coverage (WC) on the uropod, and uropod content weight-to-weight (WW) ratio of female P. clarkii were found to change significantly during ovarian development. The random forest model identified white patches on the uropod as secondary sexual characteristics of female P. clarkii. In fact, the ovarian maturity status could be determined based on the variable pattern of these white patches (distribution shape, coverage, and density), particularly WC. White patches waxed and waned during ovarian development and oviposition. Specifically, white patches were absent from the uropod of female P. clarkii before the avitellogenic stage; visible on the uropod in the early vitellogenic stage (WC < 30%); WC 30–45% occurred in the midvitellogenic stage; WC > 45% occurred in the late vitellogenic stage; and white patches disappeared from the uropod of female P. clarkii in the post-vitellogenic and resorptive stage. The accuracy of identifying mature female P. clarkii (late vitellogenic stage) based on the white patch pattern was 86.36%. Hence, the observation of white patch changes on the uropod might represent an effective method for rapidly identifying mature female P. clarkii with the potential to improve artificial intensive breeding.