Recent publications
Background and aims
Phenotypic plasticity in associations enables higher resource use efficiency and niche complementarity. This study aims to (1) examine the phenotypic plasticity of soybean functional traits to relay-cropping under drought conditions and (2) evaluate different soybean genotypes and their interactions.
Methods
A preliminary investigation comprised field experiments in micro-plots in non-irrigated conditions performed for two years (2022 and 2023) to examine trait responses to barley relay-cropping for four soybean genotypes compared to sole crops. In 2022, we experienced a record-setting drought that highly impacted the soybean yield. Ten above- and below-ground functional traits related to light interception, resource allocation and soil exploration were measured at barley harvest and one month after, at the reproductive stage.
Results
Our results showed that relay-cropping can exacerbate drought stress and, consequently, competition for water between crops. This led to phenological delay and growth abortion. However, root functional traits, such as lateral root mean angle, specific root length and root nodules densities, were higher in relay-cropping, demonstrating plant response to water stress and competition.
Conclusion
Soybean genotypes showed a plasticity of root functional traits to respond to competition and water stress. Agricultural practices (timely irrigation and/or adapting relay-cropping design) could modulate water stress, and appropriate cultivars would allow relay-cropped soybeans to sustain temporally dry conditions.
Male crickets sing to attract females for mating. Sound is produced by tegminal stridulation, where one wing bears a plectrum and the other a wing vein modified with cuticular teeth. The carrier frequency (fc) of the call is dictated by the wing resonance and the rate of tooth strikes. Therefore, the fc varies across species due to the size of the vibrating membranes on the wings and/or the speed of tooth strikes. But how well is the resonant frequency (fo) conserved in dried preserved specimens? This project is designed to investigate the gradual change in cricket wing fo over time and aims to produce equations that help to predict or recover the original natural frequency of wing vibration in dry-preserved crickets and allies. Using laser Doppler vibrometry, we scanned the wings of living specimens to determine their fo. The specimens were then preserved, allowing us to continue measuring the wings fo as they desiccate. We found that after the first week, fo increases steeply, reaching a plateau and stabilizing for the following months. We go on to propose a model that can be used to recover the original fc of the wings of preserved Ensifera that use pure tones for communication. Models were corroborated using preserved specimens previously recorded and mounted in dry collections for more than 10 years.
Ultrasound is a valuable, non-invasive technique. It allows for detailed examination, precise measurement, and effective monitoring of teats in dairy cows. This study aimed to evaluate the reliability of ultrasound measurements of teats in dairy cows, specifically focusing on intra- and inter-rater agreement between operators with different levels of experience. The study included 51 healthy Holstein cows, with two operators (experienced and inexperienced) performing measurements on ultrasound images obtained before and after milking. The parameters analyzed were teat-canal length (TCL), teat-end width (TEW), teat-wall thickness (TWT), and teat-cistern width (TCW). Differences in teat measurements before and after milking, as well as between operators, were assessed using the Wilcoxon Signed Rank test and the Mann-Whitney U test, respectively. Intra- and inter-rater agreement was calculated using the intra-class correlation coefficient (ICC). Statistical significance was set at p < 0.05. A total of 402 ultrasound images were analyzed. Significant differences were found in TCL, TWT, and TCW before and after milking, while TEW remained unaffected. Statistically significant differences in TWT and TCW were observed between the two operators, while TCL and TEW did not show significant differences. Intra-rater agreement for the experienced operator was excellent, and for the inexperienced operator, it was good. Inter-rater agreement ranged from good to excellent for most parameters, except for TWT, where it was poor. The study confirms that both milking and operator experience influence teat measurements. However, with proper training, ultrasonography can be a reliable tool for assessing udder health in dairy cows, supporting its use in field conditions.
Dietary advanced glycation end-products (dAGEs) accumulate in organs and are thought to initiate chronic low-grade inflammation (CLGI), induce glycoxidative stress, drive immunosenescence, and influence gut microbiota. Part of the toxicological interest in glycation products such as dietary carboxymethyl-lysine (dCML) relies on their interaction with receptor for advanced glycation end-products (RAGE). It remains uncertain whether early or lifelong exposure to dAGEs contributes physiological changes and whether such effects are reversible or permanent. Our objective was to examine the physiological changes in Wild-Type (WT) and RAGE KO mice that were fed either a standard diet (STD − 20.8 ± 5.1 µg dCML/g) or a diet enriched with dCML (255.2 ± 44.5 µg dCML/g) from the perinatal period for up to 70 weeks. Additionally, an early age (6 weeks) diet switch (dCML→STD) was explored to determine whether potential harmful effects of dCML could be reversed. Previous dCML accumulation patterns described by our group were confirmed here, with significant RAGE-independent accumulation of dCML in kidneys, ileum and colon over the 70-week dietary intervention (respectively 3-fold, 17-fold and 20-fold increases compared with controls). Diet switching returned tissue dCML concentrations to their baseline levels. The dCML-enriched diet had no significative effect on endogenous glycation, inflammation, oxidative stress or senescence parameters. The relative expression of TNFα, VCAM1, IL6, and P16 genes were all upregulated (∼2-fold) in an age-dependent manner, most notably in the kidneys of WT animals. RAGE knockout seemed protective in this regard, diminishing age-related renal expression of TNFα. Significant increases in TNFα expression were detectable in the intestinal tract of the Switch group (∼2-fold), suggesting a higher sensitivity to inflammation perhaps related to the timing of the diet change. Minor fluctuations were observed at family level within the caecal microbiota, including Eggerthellaceae, Anaerovoracaceae and Marinifilaceae communities, indicating slight changes in composition. Despite chronic dCML consumption resulting in higher free CML levels in tissues, there were no substantial increases in parameters related to inflammageing. Age was a more important factor in inflammation status, notably in the kidneys, while the early-life dietary switch may have influenced intestinal susceptibility to inflammation. This study affirms the therapeutic potential of RAGE modulation and corroborates evidence for the disruptive effect of dietary changes occurring too early in life. Future research should prioritize the potential influence of dAGEs on disease aetiology and development, notably any exacerbating effects they may have upon existing health conditions.
The recent development of high average, high peak power lasers has revived the effort of using lasers as a potential tool to influence natural lightning. Although impressive, the current progress in laser lightning control (LLC) technology may only be the beginning of a new area involving a positive feedback between powerful laser development and atmospheric research. In this review paper, we critically evaluate the past, present and future of LLC, considering both its technological and scientific significance in atmospheric research.
We numerically investigate the generalized Steklov problem for the modified Helmholtz equation and focus on the relation between its spectrum and the geometric structure of the domain. We address three distinct aspects: (i) the asymptotic behavior of eigenvalues for polygonal domains; (ii) the dependence of the integrals of eigenfunctions on domain symmetries; and (iii) the localization and exponential decay of Steklov eigenfunctions away from the boundary for smooth shapes and in the presence of corners. For this purpose, we implemented two complementary numerical methods to compute the eigenvalues and eigenfunctions of the associated Dirichlet-to-Neumann operator for planar bounded domains. We also discuss applications of the obtained results in the theory of diffusion-controlled reactions and formulate conjectures with relevance in spectral geometry.
The growth and invasion of solid tumors are associated with changes in their viscoelastic properties, influenced by both internal cellular factors and physical forces in the tumor microenvironment. Due to the lack of a comprehensive investigation of tumor tissue viscoelasticity, the relationship between such physical properties and cancer malignancy remains poorly understood. Here, the viscoelastic properties of breast cancer spheroids, 3D (in vitro) tumor models, are studied in relation to their metastatic potentials by imposing controlled, dynamic compression within a microfluidic constriction, and subsequently monitoring the relaxation of the imposed deformation. By adopting a modified Maxwell model to extract viscoelastic properties from the compression data, the benign (MCF‐10A) spheroids are found to have higher bulk elastic modulus and viscosity compared to malignant spheroids (MCF‐7 and MDA‐MB‐231). The relaxation is characterized by two timescales, captured by a double exponential fitting function, which reveals a similar fast rebound for MCF‐7 and MCF‐10A. Both the malignant spheroids exhibit similar long‐term relaxation and display residual deformation. However, they differ significantly in morphology, particularly in intercellular movements. These differences between malignant spheroids are demonstrated to be linked to their cytoskeletal organization, by microscopic imaging of F‐actin within the spheroids, together with cell‐cell adhesion strength.
We present a new version of a generalisation to elliptic nets of a theorem of Ward [‘Memoir on elliptic divisibility sequences’, Amer. J. Math. 70 (1948), 31–74] on symmetry of elliptic divisibility sequences. Our results cover all that is known today.
We demonstrate externally modulated widely tunable lasers co-integrated with semiconductor optical amplifiers (SOAs) heterogeneously integrated on silicon. The widely tunable laser enables continuous single-mode operation over a tuning range of approximately 40 nm, with a side-mode suppression ratio (SMSR) of at least 50 dB and an average waveguide-coupled optical power of 5 mW. The integrated electro-absorption modulator (EAM) exhibits an extinction ratio (ER) of 16 dB when reversed biased at -2 V. The bit-error-rate (BER) measurements conducted across the available optical bandwidth (15 nm) showcase error-free transmission at 32 Gbps using non-return-to-zero (NRZ) signals for the majority of wavelengths in a back-to-back (B2B) configuration. Additionally, transmission measurements over distances of up to 10 km through a standard single-mode fiber (SSMF) have been successfully demonstrated. Dynamic extinction ratio (DER) values exceeding 4.5 dB are achieved for all wavelengths. Open-eye diagrams were measured up to 56 Gbps. These results demonstrate that this compact mono-epitaxial externally modulated tunable laser with integrated optical amplification can be a cost-effective transmitter solution for dense wavelength division multiplexing (DWDM) metropolitan and access networks.
Understanding and interpreting vast amounts of information is pivotal in the contemporary data-rich age. Data visualization has emerged as a significant measure of comprehending these data. Similarly, an appropriate visualization can also enhance software modeling by providing straightforward and interactive representations. However, current data visualization methods predominantly require users to have data visualization-related expertise, which is usually challenging to obtain in reality. It is essential to bridge the gap between visualization requirements and visualization solutions for non-expert users, assisting them in automatically operationalizing their visualization requirements. This paper proposes a MUltilayer framework for analyzing and operationalizing visualization REQuirements that automatically derives appropriate visualization solutions based on users’ requirements. Specifically, we systematically investigate the connections among visualization requirements, visual variable characteristics, visual variable attributes, and visualization solutions, based on which we establish a conceptual framework that characterizes the relationships among different layers. Our proposal contributes to not only automatically operationalizing visualization requirements but also providing meaningful explanations for the derived visualization solutions. To promote our proposal and pragmatically benefit real users, we have developed and deployed a prototype tool based on the proposed framework, which is publicly available at https://reqdv.vmasks.fun. To evaluate our proposed framework, we conducted an initial controlled experiment with 44 participants to test the performance of the evolved mappings within our framework. Based on the expert’s feedback, we refined the mappings and incorporated a ranking system for visualization solutions tailored to specific requirements. To assess the current method, a subsequent experiment with another group of 44 participants and a focused case study involving two new participants were carried out. The results demonstrate that users perceive that the current method accelerates task completion, especially for complex tasks, by efficiently narrowing down options and prioritizing them. This approach is particularly advantageous for users with limited data visualization experience. Besides, the multilayer framework can be used to inspire the visualization of models in the software modeling community.
In this work, we discuss the possibility of reaching the Ziman conditions for collective heat transport in cubic bulk semiconductors, such as Si, Ge, AlAs and AlP. In natural and enriched silicon and germanium, the collective heat transport limit is impossible to reach due to strong isotopic scattering. However, we show that in hyper-enriched silicon and germanium, as well as in materials with one single stable isotope like AlAs and AlP, at low temperatures, normal scattering plays an important role, making the observation of the collective heat transport possible. We further discuss the effects of sample sizes, and analyse our results for cubic materials by comparing them to bulk bismuth, in which second sound has been detected at cryogenic temperatures. We find that collective heat transport in cubic semiconductors studied in this work is expected to occur at temperatures between 10 and 20 K.
RESUMO O uso massivo de Inteligência Artificial na moderação de conteúdo na internet é uma realidade dos tempos atuais. No entanto, isso levanta uma série de questionamentos, seja sobre a pertinência do uso de sistemas automáticos opacos, seja se as plataformas podem sozinhas tomar decisões que antes cabiam ao Estado. Nesse contexto, o uso de IA “caixa-preta” passa a ser considerado uma ameaça à liberdade de expressão. Por outro lado, manter conteúdos que promovam abuso virtual é igualmente danoso a este direito fundamental. Nesse cenário, este estudo sumariza os principais problemas apontados pela literatura quanto ao paradigma atual, avalia as respostas que as novas tecnologias trazem, e propõe um caminho para um novo paradigma de moderação que seja justo e ético, no qual Estado e plataformas de mídias sociais têm papel relevante. Esse passa pela adoção de IA explicável associada a critérios transparentes e legítimos definidos pela sociedade.
This work investigates the impact of carrier noise induced by an external current source on the linewidth enhancement factor (LEF) and relative intensity noise (RIN) of a 100 GHz quantum dot fourth-order colliding-pulse mode-locked laser (MLL), driven by a normal pump with Gaussian-distributed carrier sequences and a quiet pump with sub-Poissonian-distributed carrier sequences. The results indicate that under a normal pump, the LEFs are approximately zero for reverse saturable absorber (SA) bias voltages ranging from 0 to 2.5 V, and the laser achieves a RIN as low as −156 dB/Hz. When using a quiet pump, both the LEF and RIN are reduced across all SA bias conditions, particularly at low reverse SA bias voltages. Specifically, the LEF decreases by up to 0.58 at 0 V, and the average RIN spectrum is reduced by more than 3 dB at the same voltage. This work provides a straightforward approach for the development and optimization of multi-channel light sources for dense wavelength division multiplexing (DWDM) technologies with low optical noise.
Shared Mobility Services (SMS), e.g., demand-responsive transit or ride-sharing, can improve mobility in low-density areas, often poorly served by conventional Public Transport (PT). Such improvement is mostly quantified via basic performance indicators, like wait or travel time. However, accessibility indicators, measuring the ease of reaching surrounding opportunities (e.g., jobs, schools, shops, ...), would be a more comprehensive indicator. To date, no method exists to quantify the accessibility of SMS based on empirical measurements. Indeed, accessibility is generally computed on graph representations of PT networks, but SMS are dynamic and do not follow a predefined network. We propose a spatial-temporal statistical method that takes as input observed trips of a SMS acting as a feeder for PT and summarized such trips in a graph. On such a graph, we compute classic accessibility indicators. We apply our method to a MATSim simulation study concerning demand-responsive transport in Paris-Saclay.
Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), and per- and poly-fluoroalkyl substances (PFAS) are persistent organic pollutants (POPs) that remain detrimental to critical subpopulations, namely pregnant women. Required tests for biomonitoring are quite expensive. Moreover, statistical models aiming to discover the relationships between pollutants levels and human characteristics have their limitations. Therefore, the objective of this study is to use machine learning predictive models to further examine the pollutants’ predictors, while comparing them. Levels of 33 congeners were measured in the serum of 269 pregnant women, from whom data was collected regarding sociodemographic, dietary, environmental, and anthropometric characteristics. Several machine learning algorithms were compared using “Python” for each pollutant: support vector machine (SVM), random forest, XGBoost, and neural networks. The aforementioned characteristics were included in the model as features. Prediction, accuracy, precision, recall, F1-score, area under the ROC curve (AUC), sensitivity, and specificity were retrieved to compare the models between them and among pollutants. The highest performing model for all pollutants was Random Forest. Results showed a moderate to acceptable performance and discriminative power among all POPs, with OCPs’ model performing slightly better than all other models. Top related features for each model were also presented using SHAP analysis, detailing the predictors’ negative or positive impact on the model. In conclusion, developing such a tool is of major importance in a context of limited financial and research resources. Nevertheless, machine learning models should always be interpreted with caution by exploring all evaluation metrics.
The management of extensive tracheal resection followed by circumferential replacement remains a surgical challenge. Numerous techniques are proposed with mixed results. Partial decellularization of the trachea with the removal of the mucosal and submucosal cells is a promising method, reducing immunogenicity while preserving the biomechanical properties of the final matrix. Despite many research protocols and proofs of concept, no standardized clinical grade protocol is described. Furthermore, local and systemic biointegration mechanisms of decellularized trachea are not well known. Therefore, in a translational research perspective, this work set up a partial tracheal decellularization protocol in line with Cell and Tissue Products regulations. Extensive characterization of the final product is performed in vitro and in vivo. The results show that the Partially Decellularized Trachea (PDT) is cell‐free in the mucosa and submucosa, while the cartilage structure is preserved, maintaining the biomechanical properties of the trachea. When implanted in the muscle in vivo for 28 days, no systemic inflammation is observed, and locally, the PDT shows an excellent biointegration and vascularization. No signs of graft rejection are observed. These encouraging results confirmed the efficacy of the clinical grade PDT production protocol, which is an important step for future clinical applications.
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