Limited Range Research Articles

Effects of educational disruption and changes in school context on children's mental health: Associations with school level disadvantage and individual bullying involvement

AbstractNatural disasters happen across the world. The situations are different but the disruption to children's education and wellbeing is similar. This study focused on the school context changes caused by the COVID‐19 global disaster, and the impact of these changes on children's mental health. The aim was to better understand the associations between any mental health changes and children's school level of deprivation and pre‐disaster involvement in bullying. Cross‐sectional data were collected from 4316 children aged 6–11 years old, from 57 schools across England and Wales. Data were collected before the national lockdowns, early 2020, and 3–5 months after the final return to school, summer 2021, when schools were operating under a range of context restrictions. Child data included bullying involvement at school and health‐related quality of life; teacher data included reports of each child's internalising, externalising and prosocial behaviours. School‐level disadvantage was determined by the proportion of children in each school eligible to receive free school meals (an indicator of family disadvantage). The results showed that victims of bullying pre‐lockdown, and pupils from schools with a higher concentration of disadvantage, had significantly reduced externalising behaviours once back in the restricted school context. Victims had also increased their prosocial behaviours. It is possible that the restricted school context may have been a relief for the most vulnerable pupils. This study adds a new phase of understanding to the global disaster literature and the initial return to school when the environment is the same but the context has changed.

A new electrochemical biosensor based on graphene oxide for rapid detection of synthetic testosterone as performance-enhancing drugs in athletes

This study showcases the successful development of a hybrid reduced graphene oxide-metal organic framework modified glassy carbon electrode (rGO-MOFs/GCE) electrochemical biosensor for the detection of synthetic testosterone (TST) as a performance-enhancing drug in athletes. The results demonstrate a linear relationship between the voltametric responses and the testosterone concentration, indicating the sensor's effectiveness in measuring TST. Furthermore, the sensor's performance in detecting TST in real human serum samples from athletes was also validated. The sensor's linear range and detection limit are comparable, if not superior, to those of other recently developed electrochemical sensors, positioning it as a promising tool for TST detection. Additionally, the method's selectivity was assessed and found to be unaffected by substances typically present in biological fluids and food samples, further affirming the sensor's reliability. The application of the rGO/MOF/GCE sensor to detecting and quantifying TST in actual human serum samples yielded favorable results. The synergistic effects of rGO and MOF, which improve the electrical conductivity and biocompatibility of MOF and the porosity and catalytic activity of rGO, are responsible for the sensor's enhanced performance in terms of sensitivity, selectivity, stability, and response time. These findings underscore the potential of the rGO/MOF/GCE sensor platform for various biomedical applications.

Novel biocompatible N-rich AIE fluorescent probe for live cell imaging and visual onsite detection of uranium.

A sensitive and biocompatible N-rich probe for rapid visualuranium detectionwas constructed by grafting two trianiline groups to 2,6-bis(aminomethyl)pyridine. Possessing excellent aggregation-induced emission (AIE) property and the advantages to form multidentate chelate with U selectively, the probe has been applied successfully to visualize uranium in complex environmental water samples and living cells, demonstrating outstanding anti-interference ability against large equivalent of different ions over a wide effective pH range. A large linear range (1.0 × 10-7-9.0 × 10-7mol/L) and low detection limit (72.6nmol/L, 17.28ppb) were achieved for the visual determination of uranium. The recognition mechanism, photophysical properties, analytical performance and cytotoxicity were systematically investigated, demonstrating highpotential for fast risk assessment of uranium pollution in field and in vivo.

Taraxacum sect. Erythrosperma (Asteraceae, Cichorioideae) in Slovakia IV. Distribution of T. erythrospermum and synonymisation of T. slovacum

The group of lesser dandelions (Taraxacum sect. Erythrosperma) is represented by more than 215 species growing in mostly xerothermic habitats throughout Europe. The only known species with sexual reproduction in this section is the diploid T. erythrospermum. It occurs in southern parts of Europe and reaches its northern limit in central Europe. In this study, we aimed at a detailed mapping of the species distribution in Slovakia in order to understand the spatial distribution at its northern range limits. We found that it is the most common xerothermous species in Slovakia, growing on various substrates such as limestone, dolomite, travertine, volcanic rocks and sands, while it is less common on brown soils and ruderal biotopes. It is a characteristic species of the class Festuco-Brometea with an altitudinal range extending from 120 to 650 m above sea level. We delimited the northern distribution and documented its highest occurrence at approximately ca 1500 m a.s.l. Two taxa, T. slovacum and T. punctatum, were described from the territory of Slovakia and we discuss their relationships to T. erythrospermum, with which T. slovacum is synonymised here for the first time. We also present new data on the genome size of T. erythrospermum in Slovakia, which range from 1.529 to 1.604 pg with a mean of 1.554 pg (± 0.024 SD), and provide chorological data on a remarkable morphological variant with grey-coloured achenes.

BM-RCWTSG: An integrated matching framework for electric vehicle ride-hailing services under stochastic guidance

Electric vehicles (EVs) are playing an increasingly vital role in sustainable ride-hailing services, primarily due to their potential to reduce carbon emissions and enhance environmental well-being. A core service of ride-hailing platforms is to match riders with nearby drivers within a short time window. In this mandate, it is crucial to ensure a high matching rate and low rider waiting time since these are key indicators of customer satisfaction and the platform’s operational effectiveness. However, existing matching mechanisms in the literature failed to consider important aspects related to EVs, including the range limit, charging detour time, and charging waiting time. These factors can significantly affect the system matching rate, rider waiting time, and vehicle utilization rate. To address the new challenges of the increased adoption of EVs in ride-hailing services, we propose a data-driven stochastic optimization framework for EV ride-hailing matching. The proposed framework integrates two stochastic optimization models, namely the stochastic guidance (SG) model and the EV matching (EVM) model. The SG model optimizes EV relocation and improves the system matching rate by proactively guiding idle EVs to the designated regions based on probabilistic rider demand forecasting. The EVM model utilizes the relocated EVs and current rider demands to provide the optimal matching solution that minimizes the overall cost associated with rider waiting time, EV charging waiting time, and charging detours. We conduct experimental validation of this approach using two real-world data sets from New York City. Comparative results suggest that by utilizing the proposed framework, the matching rate can be increased up to 22.9%, and the rider and EV waiting times can be reduced up to 14.9% and 73.6%, respectively, compared to the benchmark models.

Covalent copper-organic frameworks with light-activable catalytic centers as smart artificial enzymes for highly sensitive and wide-range biocatalytic diagnosis

As a popular sensing method, colorimetric biosensing has the advantages of convenient operation, low cost, fast response, and easy readout. However, due to the complex structure of nanomaterials, low catalytic activity, and unclear catalytic mechanisms, constructing efficient, stable, and specific artificial biocatalysts for colorimetric biosensing is still a challenge. In this study, to propose a new colorimetric biosensing system, we synthesize three different types of copper cyclic trinuclear unit-based 2D copper-organic frameworks (CuOFs) with covalent structures and light-activable catalytic centers to serve as smart artificial enzymes for highly sensitive and wide-range biocatalytic diagnosis. By varying the light absorption centers, CuOFs with different band structures, light absorption capacity, photoelectron transfer efficiency, and electron-hole pair separation efficiency can be obtained. Of the three covalent CuOFs, tris(4-aminophenyl)amine (Tpa)-Cu3 exhibited the widest light absorption range, the narrowest band gap, the smallest electron transfer barrier, and the best-photoinduced charge separation efficiency, which was conducive to improving the light capture ability and eventually improving the photocatalytic properties. Further tests demonstrated that Tpa-Cu3 exhibited the best peroxidase-like activity under visible light irradiation, which could effectively diagnose the glucose and common antioxidants with a wider detection range and lower detection limit than many previously reported biocatalytic materials. We expect this design will provide new insights into enzyme-like organic framework materials and unique systems for high-sensitive and wide-range colorimetric detection for future biocatalytic applications.

Hollow Cu/CoS2 Nanozyme with Defect-Induced Enzymatic Catalytic Sites and Binding Pockets for Highly Sensitive Fluorescence Detection of Alkaline Phosphatase.

Along with an ever-deepening understanding of the catalytic principle of natural enzymes, the rational design of high-activity biomimetic nanozymes has become a hot topic in current research. Inspired by the active centers of natural enzymes consisting of catalytic sites and binding pockets, a Cu-doped CoS2 hollow nanocube (Cu/CoS2 HNCs) nanozyme integrating substitution defects and vacancies is developed through a defect engineering strategy. It is shown that the vacancies and substitution defects in the developed Cu/CoS2 HNC nanozymes serve as binding pockets and catalytic sites, respectively. The construction of this key active center and the accelerated electron transfer from the Co/Cu redox cycle significantly improve the substrate affinity and catalytic efficiency of the Cu/CoS2 HNCs nanozymes, which results in the excellent catalytic performance of the Cu/CoS2 HNC nanozymes. Using the superior enzymatic activity of Cu/CoS2 HNCs, a fluorescence detection platform for alkaline phosphatase (ALP) is established, which is a wider detection range and lower limit of detection (LOD) than previous work. This work broadens the family of nanozymes and provide a new idea for the development of novel nanozymes with high enzyme activity, as well as a guideline for the construction of highly sensitive fluorescent sensors.

A facile and efficient voltammetric sensor for marbofloxacin detection based on zirconium-based metal-organic framework UiO-66/nitrogen-doped graphene nanocomposite

Improper and persistent use of marbofloxacin (MAR) is prone to produce residues that deteriorate the surrounding environment and endanger our health. Hence, it is urgent to stablish a facile and efficient detection technique for the detection of MAR. Herein, a highly efficient electrochemical platform was constructed for sensitive determination of MAR using zirconium-based metal–organic framework (UiO-66)/nitrogen-doped graphene (NG) nanocomposites (UiO-66/NG). The surface morphology, crystalline phase, elemental composition, and electrochemical behavior of UiO-66/NG were characterized by various spectroscopic and electrochemical techniques. Owing to the synergistic interaction of UiO-66 MOFs and NG nanosheets, the UiO-66/NG exhibited remarkable catalytic activity for MAR oxidation. As consequently, the UiO-66/NG demonstrated a wide linear response range (0.01 − 10 μM), high sensitivity (1.80 μM μA−1 cm−2) and low detection limit (0.002 μM). The proposed UiO-66/NG/GCE demonstrated robust voltammetric responses even in the presence of excess potential interfering species and retained stable response signals for at least two weeks. More importantly, the proposed UiO-66/NG/GCE displayed highly consistent sensitivity toward MAR detection in both aquaculture water and milk matrices and PBS buffer, and achieved accurate and sensitive detection of MAR with good recovery. Together with its low cost and facile operation, the UiO-66/NG/GCE shows great prospects for trace detection of MAR from complex matrices.

Time-delayed single satellite quantum repeater node for global quantum communications

Global-scale quantum networking faces significant technical and scientific obstacles. Quantum repeaters (QRs) have been proposed to overcome the inherent direct transmission range limit through optical fiber. However, QRs are typically limited to a total distance of a few thousand kilometers and/or require extensive hardware overhead. Recent proposals suggest that strings of space-borne QRs with on-board quantum memories (QMs) are able to provide global coverage. Here, we propose an alternative to such repeater constellations using a single satellite with two QMs that effectively acts as a time-delayed version of a single QR node. By physically transporting stored qubits, our protocol improves long-distance entanglement distribution with reduced system complexity over previous proposals. We estimate the amount of secure key in the finite block regime and demonstrate an improvement of at least three orders of magnitude over prior single-satellite methods that rely on a single QM, while simultaneously reducing the necessary memory capacity similarly. We propose an experimental platform to realize this scheme based on rare-earth ion doped crystals with appropriate performance parameters. By exploiting recent advances in quantum memory lifetimes, we are able to significantly reduce system complexity while achieving high key rates, bringing global quantum networking closer to implementation.

Implementation and Analysis of an Efficient Soft-Switching Battery Wireless Charger with Re-Configurable Rectifier

To significantly reduce switching loss of the high frequency inverter in battery wireless charger (BWC), improve the soft-switching stability and system reliability, a novel soft-switching BWC with low loss auxiliary network and re-configurable rectifier is presented. The presented soft-switching BWC can implement the smooth switching between constant current mode (CCM) and constant voltage mode (CVM) without frequency switching and relays, which is beneficial to enhancing the system stability. With the help of a novel low energy consumption auxiliary circuit, the power switch tubes in the H-bridge inverter can implement zero-voltage soft switch-ON and zero-current soft switch-OFF in the full range, completely eliminating switching loss of the inverter. The proposed scheme can enhance the system efficiency while refraining from the soft-switching range limitation and soft-switching failure caused by the system parameter perturbation. Finally, a 1-kW soft-switching BWC principle prototype is developed to validate the effectiveness and correctness of the proposed scheme.

Residual protein analysis by SDS-PAGE in clinically manufactured BM-MSC products.

Residual substances that are considered hazardous to the recipient must be removed from final cellular therapeutic products manufactured for clinical purposes. In doing so, quality rules determined by competent authorities (CAs) for the clinical use of tissue- and cell-based products can be met. In our study, we carried out residual substance analyses, and purity determination studies of trypsin and trypsin inhibitor in clinically manufactured bone marrow-derived mesenchymal stromal/stem cell products, using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method. Despite being a semiquantitative method, SDS-PAGE has several benefits over other methods for protein analysis, such as simplicity, convenience of use, and affordability. Due to its convenience and adaptability, SDS-PAGE is still a commonly used method in many laboratories, despite its limits in dynamic range and quantitative precision. Our goal in this work was to show that SDS-PAGE may be used effectively for protein measurement, especially where practicality and affordability are the major factors. The results of our study suggest a validated method to guide tissue and cell manufacturing sites for making use of an agreeable, accessible, and cost-effective method for residual substance analyses in clinically manufactured cellular therapies.

Queen Triggerfish Balistes vetula Age-Based Population Demographics and Reproductive Biology for Waters of the North Caribbean

Queen triggerfish Balistes vetula is an important reef-associated species for commercial fisheries in the U.S. Caribbean. It exhibits a relatively unique reproductive strategy as a nesting benthic spawner, investing substantial energy in territorial defense, building and maintaining nests, and caring for fertilized eggs during the reproductive season. Prior to this study, no comprehensive life history information existed in the literature for queen triggerfish. This study provides the first comprehensive documentation of age, growth, size/age at sexual maturity, reproductive seasonality, and reproductive output for a Balistes species in the Caribbean. From 2013 to 2023, we collected 2190 fish samples from fisheries-dependent and -independent sources from the waters of Puerto Rico and the U.S. Virgin Islands. Fish ranged from 67 to 477 mm fork length (FL). We documented that queen triggerfish is sexually dimorphic with males attaining larger mean sizes-at-age compared to females and the species is characterized by a moderately young age at median sexual maturity (A50 = 3.3 y). The maximum age for our U.S. Caribbean samples was 23 y based on increment counts from otoliths. Spawning season encompassed the months of December to August in the region, and female spawning frequency ranged from an estimated 2 to 84 times per year; female spawning frequency increased with increasing size and age of fish. We documented that commercial fishers in the U.S. Caribbean mainly target “plate-size” individuals, defined in our study as 235–405 mm FL, which appears to act as a self-imposed slot size range limit and results in the fishery not removing individuals in the smallest and largest size groups at high rates. The percentage of immature fish from fisheries-dependent sources was close to 0 (0.8%). Commercial fishing for queen triggerfish in the region currently appears to be sustainable, but monitoring of the population should continue.

Recent records of thermohaline profiles and water depth in the Taam ja’ Blue Hole (Chetumal Bay, Mexico)

Coastal karst structures have been recently explored and documented in Chetumal Bay, Mexico, at the southeast of the Yucatan Peninsula. These structures, recognized as blue holes, stand out for their remarkable dimensions within a shallow estuarine environment. Particularly the Taam Ja’ Blue Hole (TJBH), revealed a depth of ~274 mbsl based on echo sounder mapping, momentarily positioning it as the world's second-deepest blue hole. However, echo sounding methods face challenges in complex environments like blue holes or inland sinkholes arising from frequency-dependent detection and range limitations due to water density vertical gradients, cross-sectional depth variations, or morphometric deviations in non-strictly vertical caves. Initial exploration could not reach the bottom and confirm its position, prompting ongoing investigation into the geomorphological features of TJBH. Recent CTD profiler records in TJBH surpassed 420 mbsl with no bottom yet reached, establishing the TJBH as the deepest-known blue hole globally. Hydrographic data delineated multiple water layers within TJBH. Comparison with Caribbean water conditions at the Mesoamerican Barrier Reef System, reef lagoons, and estuaries suggests potential subterranean connections. Further research and implementation of underwater navigation technologies are essential to decipher its maximum depth and the possibilities of forming part of an interconnected system of caves and tunnels.

Facile and efficient synthesis of sweater-ball shaped metal-organic framework/nickel sulfide nanoheterojunction for boosting electrochemical glucose sensing

The synthesis of heterojunction materials is regarded as an efficient way to enhance catalytic activities in various catalytic reactions. However, the existing fabrication approaches often rely on complex multi-step synthesis process. In this work, we fabricate sweater-ball shaped nanostructured MOF/TMS (Ni-MOF/NiS1.03) heterojunction by one-pot, one-step solvothermal method. According to the results of discrete Fourier transform (DFT) calculations and experiments, the formation of Ni-MOF/NiS1.03 heterojunction interfaces improves electron transfer and charge redistribution, and increases the adsorption energy of glucose molecules as well, which is conducive to enhance electrochemical activity of electrode materials. The as-prepared Ni-MOF/NiS1.03 heterojunction exhibit enhanced glucose sensitivity, wide detection range and low detection limit. This study paves the way towards the development of MOF-based heterojunctions for electrochemical applications.

Ultrasensitive dual-mode detection of amyloid β oligomer via Au NRs modulated photoelectrochemical/electrochemiluminescent response from HOFs/g-C3N4

In this work, a heterojunction composite of HOFs/g-C3N4 was synthesized using solution-plasticized self-assembly of g-C3N4 nanosheet on hydrogen-bonded organic frameworks (HOFs). HOFs/g-C3N4 was then used as a substrate material to construct a novel photoelectrochemical/electrochemiluminescent (PEC/ECL) biosensor for the detection of amyloid β oligomer (Aβo). HOFs/g-C3N4 composites were first drop-coated on the electrode surface. Subsequently, the Aβ aptamer was modified on the electrode surface via amide bonding. The target Aβo and the gold nanorods (Au NRs)-labeled Aβ recognition peptide (Au NRs-KLVFF) were simultaneously dropped onto the electrode surface, thus a “sandwich” dual-mode biosensor was constructed. In the PEC detection of the Aβo, the surface plasmon resonance effect of Au NRs enhanced the visible absorption of HOF/g-C3N4, and the sensor exhibited a "signal-on" photocurrent signal. Meanwhile, the ECL emission spectrum of HOF/g-C3N4 in ECL mode overlaps with the ultraviolet-visible (UV) absorption of Au NRs, and the sensor signal showed a “signal-off” ECL response. Under the optimal conditions experiments, the constructed dual-mode biosensor showed a wide detection range and low detection limit for Aβo. The proposed dual-mode detection method has a detection range of 10 fM to 10 nM with a detection limit of 5.97 fM for PEC detection and a detection range of 0.1 pM to 1.0 μM with a detection limit of 0.051 pM for ECL detection respectively. Additionally, the detection method achieved satisfactory results in the analysis of real samples. Dual-mode sensing platform provides a new strategy for HOFs application in PEC/ECL assay and sensitive detection of AβO.

Digest: Sexual selection may shape species' range limits.

In a recent study, Tschol et al. (2024) present a model that investigates how 2 different forms of sexual selection, selection for traits that increase mate encounters and selection for traits that enhance one's ability to compete for mates, affect geographical range limits. The model demonstrates that range limits expand in response to selection on mate-encountering traits and contract when selection acts on reproductive competitiveness. When traits coevolve, range limits depend on the mating system. This study demonstrates the importance of accounting for sexual selection and intraspecific interactions when investigating eco-evolutionary dynamics of geographic range limits.

Extended measurement range of optical profiler using chirped fiber Bragg grating-based chirped spectral-domain interferometry

A conventional spectral-domain interferometer (SDI) has limitations in measurement range due to using broadband sources with low coherence lengths and spectrometers with limited pixel numbers. We propose chirped spectral-domain interferometry (CSDI) to extend the measurement range. The CSDI exploits chirped fiber Bragg gratings (CFBG) to induce dispersion in the reference arm and generates a chirped interference signal from an unbalanced interferometer. Convolution-based signal processing allows us to uniquely determine the surface position of the sample from the chirped interference signal. The sample surface geometry could then be reconstructed by analyzing the change in position of the convolution peaks. From the theoretical background, we know that the maximum measurable range of the CSDI is determined by the effective refractive index and length of the CFBG used. Experimentally, a maximum measuring range of 59 mm was measured. It is a significant improvement over conventional SDI, despite using a broadband light source and a limited number of pixels. We developed the surface profiler and demonstrated its performance in surface imaging on various samples with different reflectivity.

Metal-organic frame material encapsulated Rhodamine 6G: A highly sensitive fluorescence sensing platform for the detection of picric acid contaminants in water

As a water pollutant with excellent solubility, 2,4,6-trinitrophenol (also known as picric acid, PA) poses a potential threat to the natural environment and human health, so it is crucial important to detect PA in water. In this study, a novel composite material (MIL-53(Al)@R6G) was successfully synthesized by encapsulating Rhodamine 6G into a metal-organic frame material, which was used for fluorescence detection of picric acid (PA) in water. The composite exhibits bright yellow fluorescence emission with a fluorescence quantum yield of 58.23 %. In the process of PA detection, the composite has excellent selectivity and anti-interference performance, and PA can significantly quench the fluorescence intensity of MIL-53(Al)@R6G. MIL-53(Al)@R6G has the advantages of fast detection time (20 s), wide linear range (1–100 µM) and low detection limit (4.8 nM). In addition, MIL-53(Al)@R6G has demonstrated its potential for the detection of PA in environmental water samples with satisfactory results.

Biomonitoring urinary pesticide metabolites in preschool children by supported liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry and their association with oxidative stress

Investigating pesticide exposure and oxidative stress in preschool children is essential for elucidating the determinants of environmental health in early life, with human biomonitoring of urinary pesticide metabolites serving as a critical strategy for achieving this objective. This study demonstrated biomonitoring of 2 phenoxyacetic acid herbicides, 2 organophosphorus pesticide metabolites, and 4 pyrethroid pesticide metabolites in 159 preschool children and evaluated their association with oxidative stress biomarker 8-hydroxydeoxyguanosine. An enzymatic deconjugation process was used to release urinary pesticide metabolites, which were then extracted and enriched by supported liquid extraction, and quantified by ultra-high performance liquid chromatography-tandem mass spectrometry with internal standard calibration. Dichloromethane: methyl tert‑butyl ether (1:1, v/v) was optimized as the solvent for supported liquid extraction, and we validated the method for linear range, recovery, matrix effect and method detection limit. Method detection limit of the pesticide metabolites ranged from 0.01 μg/L to 0.04 μg/L, with satisfactory recoveries ranging from 70.5 % to 95.5 %. 2,4,5-Trichlorophenoxyacetic acid was not detected, whereas the other seven pesticide metabolites were detected with frequencies ranging from 10.1 % to 100 %. The concentration of urinary pesticide metabolites did not significantly differ between boys and girls, with the median concentrations being 9.39 μg/L for boys and 4.90 μg/L for girls, respectively. Spearman correlation analysis indicated that significant positive correlations among urinary metabolites. Bayesian kernel machine regression revealed a significant positive association between urinary pesticide metabolites and 8-hydroxydeoxyguanosine. Para-nitrophenol was the pesticide metabolite that contributed significantly to the elevated level of oxidative stress.

Greener leaves from northern trees: Latitudinal compensation in riparian cottonwoods

Narrowleaf cottonwoods (Populus angustifolia) occur in disjunct populations along rivers in a north-south corridor of the Rocky Mountain regions from Alberta, Canada, to Arizona, USA. This distribution should allow genetic divergence to provide localized ecophysiological adaptation. To test this, we compared 167 genotypes in ten source populations from across the full latitudinal range of 16° (1800 km). Replicated clonal saplings were grown for three years in a common garden at the northern range limit, where we found that shoot characteristics were correlated with the latitude of origin. Southern populations displayed increased height and stem diameter (populations: r2 = 0.489 and 0.472) due to extended in-leaf growing seasons. However, this produced a phenological mismatch, with increased fall frost injury and shoot die-back. With increasing latitude of origin there were foliar differences across the populations, with higher chlorophyll content (chl, r2 = 0.836), nitrogen (N, r2 = 0.429), and leaf mass per area (LMA, r2 = 0.474). Similar latitudinal correspondences were observed across the individual genotypes, again with the strongest correlation for chl (r2 = 0.188). Across the genotypes, chl was positively correlated with leaf length, width, area, and mass, and especially with foliar N (r2 = 0.354), which was also correlated with foliar δ13C (r2 = 0.230). The heritable correspondences between source latitude and foliar characteristics could enable vigorous photosynthesis during the shorter, northern growing season, providing latitudinal compensation. Conversely, slower photosynthesis would reduce the foliar aging rate, enabling leaf function through the longer, southern growing season. The alternate foliar strategies could accommodate the limited ‘leafspan’, or leaf lifespan. This adaptive variation in foliar physiology would impact natural or assisted northward migration of cottonwood populations in response to climate change. It could also be useful for poplar breeding, with northern genotypes contributing genes to increase photosynthetic capacity. Finally, groupings of the populations based on the combined ecophysiological traits were very consistent with genetically defined ecotypes, supporting the evolution of subspecies types within this obligate riparian tree.