Center for Scientific Research and Higher Education at Ensenada

Metals are pollutants of global concern, causing deleterious risk effects on fish physiological processes. The present study evaluates the toxic effects of cadmium (Cd), mercury (Hg) and their mixture on bullseye puffer (Sphoeroides annulatus) and spotted rose snapper (Lutjanus guttatus) sperm motility. Sperm samples of five mature males of each species were mixed with Cortland’s solution plus different concentrations of Cd, Hg, or the Cd-Hg mixture. The sperm motility percentage in both species was evaluated under a light microscope; as for Cd exposure trial, S. annulatus and L. guttatus sperm motility percentage showed a time and dose-dependent effect. As expected, a deleterious effect was observed at Hg concentrations lower than those of Cd levels. A synergistic effect was observed for the metal mixture (Cd + Hg), since lower sperm motility values were recorded in this experiment than those of the individual bioassays. The present research is of ecological concern in fishes with external fertilization inhabiting coastal zones with high Cd and Hg levels, affecting the reproductive success.

Soil salinity is a major limiting factor for agricultural crops, which increases their susceptibility to pathogenic attacks. This is particularly relevant for tomato (Solanum lycopersicum), a salt-sensitive crop. Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, is a significant threat to tomato production in both greenhouse and field environments. This study evaluated the salinity tolerance, biocontrol, and plant growth-promoting properties of Bacillus velezensis AF12 and Bacillus halotolerans AF23, isolated from soil affected by underground fires and selected for their resistance to saline conditions (up to 1000 mM NaCl). In vitro assays confirmed that both strains produced siderophores, indole-3-acetic acid (IAA), and proteases and exhibited phosphate solubilization under saline stress (100–200 mM NaCl). AF23 exhibited synergistic interactions with AF12, and inoculation with either strain individually or in combination significantly improved the growth of the Bonny Best tomato cultivar under 200 mM saline stress, leading to increased shoot and root weight, enhanced chlorophyll content, and higher total biomass. The biocontrol potential of AF12 and AF23 was evaluated in tomato plants infected with F. oxysporum. Both strains, individually or combined, increased shoot and root weight, chlorophyll content, and total biomass under non-saline conditions, promoting growth and reducing infection rates under saline stress (100 mM NaCl). Genomic analysis revealed that both strains harbored genes related to salt stress tolerance, biocontrol, and plant growth promotion. In conclusion, Bacillus strains AF23 and AF12 demonstrated strong potential as bioinoculants for enhancing tomato growth and providing protection against F. oxysporum in saline-affected soils.

Chronic respiratory diseases affect people worldwide, but conventional diagnostic methods may not be accessible in remote locations far from population centers. Sounds from the human respiratory system have displayed potential in autonomously detecting these diseases using artificial intelligence (AI). This article outlines the development of an audio-based edge computing system that automatically detects chronic respiratory diseases (CRDs). The system utilizes machine learning (ML) techniques to analyze audio recordings of respiratory sounds (cough and breath) and classify the presence or absence of these diseases, using features such as Mel frequency cepstral coefficients (MFCC) and chromatic attributes (chromagram) to capture the relevant acoustic features of breath sounds. The system was trained and tested using a dataset of respiratory sounds collected from 86 individuals. Among them, 53 had chronic respiratory conditions, including asthma and chronic obstructive pulmonary disease (COPD), while the remaining 33 were healthy. The system’s final evaluation was conducted with a group of 13 patients and 22 healthy individuals. Our approach demonstrated high sensitivity and specificity in the classification of sounds on edge devices, including smartphone and Raspberry Pi. Our best results for CRDs reached a sensitivity of 90.0%, a specificity of 93.55%, and a balanced accuracy of 91.75% for accurately identifying individuals with both healthy and diseased. These results showcase the potential of edge computing and machine learning systems in respiratory disease detection. We believe this system can contribute to developing efficient and cost-effective screening tools.

In this work, we address the problem of achieving flocking behavior in a group of nonholonomic wheeled mobile robots without using attitude measurements. Based on the cascade structure of the kinematic model of the mobile robot, we propose a dynamic controller that drives the position of each robot to a desired geometric pattern while maintaining a desired linear velocity. To overcome the problem of lack of attitude measurements, we propose an attitude observer that estimates the direction of the robot’s velocity. The interaction between robots is modeled using graph theory and the stability analysis is carried out by exploiting the properties of interconnected nonlinear systems. Experimental results on a group of four robots are provided to show the performance of the proposed control-observer algorithm.

Plant ecological strategies are shaped by numerous functional traits and their trade‐offs. Trait network analysis enables testing hypotheses for the shifting of trait correlation architecture across communities differing in climate and productivity. We built plant trait networks (PTNs) for 118 species within six communities across an aridity gradient, from forest to semi‐desert across the California Floristic Province, based on 34 leaf and wood functional traits, representing hydraulic and photosynthetic function, structure, economics and size. We developed hypotheses for the association of PTN parameters with climate and ecosystem properties, based on theory for the adaptation of species to low resource/stressful environments versus higher resource availability environments with greater potential niche differentiation. Thus, we hypothesized that across community PTNs, trait network connectivity (i.e., the degree that traits are intercorrelated) and network complexity (i.e., the number of trait modules, and the degree of trait integration among modules) would be lower for communities adapted to arid climates and higher for communities adapted to greater water availability, similarly to trends expected for phylogenetic diversity, functional richness and productivity. Further, within given PTNs, we hypothesized that traits would vary strongly in their network connectivity and that the traits most centrally connected within PTNs would be those with the least across‐species variation. Across communities from more arid to wetter climates, PTN architecture varied from less to more interconnected and complex, in association with functional richness, but PTN architecture was independent of phylogenetic diversity and ecosystem productivity. Within the community PTNs, traits with lower species variation were more interconnected. Synthesis. The responsiveness of PTN architecture to climate highlights how a wide range of traits contributes to physiological and ecological strategies with an architecture that varies among plant communities. Communities in more arid environments show a lower degree of phenotypic integration, consistent with lesser niche differentiation. Our study extends the usefulness of PTNs as an approach to quantify tradeoffs among multiple traits, providing connectivity and complexity parameters as tools that clarify plant environmental adaptation and patterns of trait associations that would influence species distributions, community assembly, and ecosystem resilience in response to climate change.

This paper discusses information collected from original articles published between 1992 and 2022 regarding heavy metals (HMs) contamination in various environments across Mexico. The primary aim of this work was to identify the Mexican states where concentrations of HMs have been reported to exceed the maximum permissible limits for several types of soil, water, and sediment according to Mexican standards NOM-147-SEMARNAT/SSA1-2004, NOM-127-SSA1-2021, as well as international standards. The data collected indicates that 25 states in Mexico have reported at least one metal exceeding the maximum permissible limits in soil. Among these, Zacatecas, Nuevo Leon and Chihuahua had the highest number of HMs exceeding the standards. For sediment contamination, 26 states exceeded the permissible limits, with San Luis Potosí and Guerrero showing the highest number of HMs above the standards. Additionally, 26 states have reports of HMs exceeding the permissible limits in water, with Guanajuato and Guerrero having the highest number of HMs. Interestingly, the most frequent metals reported as soil contaminants are Cu, Fe, Pb and Zn; in sediment, they are Cd, Cr, Cu, Fe, Pb and Zn; and in water, they are Cd, Cr, Cu, Fe, Mn, Pb and Zn. The compiled information indicates that the primary anthropogenic sources of HMs release in Mexico include industrial activities, urban wastewater, mining, and agricultural practices. Furthermore, the data analyzed highlights several serious health risks associated with exposure to HMs, including cancer, central nervous system damage, DNA damage, and issues related to kidneys and lungs. This paper provides a comprehensive overview of HMs contamination in Mexico as well as the health challenges that arise from this contamination. .

This paper deals with the stabilization of a linear hyperbolic system subject to a boundary disturbance. Our feedback design relies on the strategy called active disturbance rejection control (ADRC). The unknown disturbance is estimated by an extended state observer. We prove the existence of solutions of the closed‐loop system and the global asymptotic stability of the closed‐loop system. A numerical example is given to illustrate the efficiency of our strategy.

This study focuses on the fabrication and characterization of ZrO2‒TiO2 mixed oxides modified with gallium and surfactants and their potential application as supports for NiW hydrodesulfurization (HDS) catalysts. The mixed oxides were synthesized via the soft template sol‒gel method with the incorporation of triblock copolymers as surfactants (P123 and L64). We focus on the incorporation of gallium into the supports to modify their surface properties and acidity. The NiW catalysts were evaluated in the HDS of dibenzothiophene (DBT) under high pressure conditions. The results demonstrated that the incorporation of surfactants induced an increase in surface area and an improvement in pore structure within the oxides, which in turn led to enhanced dispersion of the active phases. Additionally, gallium facilitated the sulfidation of the W species and the formation of the NiWS active phase. The catalytic test demonstrated that the catalyst prepared with surfactants, particularly the NiW/ZT-P-Ga catalyst, exhibited the highest initial reaction rates and selectivity toward the hydrogenation pathway. The study demonstrated that the combination of surfactants and gallium ions in the preparation of ZrO2–TiO2 supports can significantly enhance the performance of NiW catalysts for deep desulfurization. These findings contribute to the development of more efficient catalysts for industrial HDS processes, addressing the challenges posed by refractory sulfur compounds in fuels.

Proteins with internal repeats (PIRs) are the second most abundant class of fungal cell wall resident proteins. In yeasts, PIRs preserve the stability of the cell wall under stressful conditions. They are characterized by conserved N‐terminal amino acid sequences repeated in tandem (PIR motifs), and a cysteine (Cys)‐rich C‐terminal domain. PIRs have been identified in several filamentous fungi genomes; however, they have not been studied beyond yeasts. In this work, the diversity, evolution, and biological role of PIRs, with a particular focus on a new PIRs class, was addressed. Bioinformatic inference of PIRs in fungi indicated they were an innovation in Ascomycota. Predicted PIRs clustered in two main groups: classical yeasts PIRs (N‐terminal PIR motifs; C‐terminal Cys‐rich domain), and PIRs from filamentous fungi with an inverted architecture (N‐terminal Cys‐rich domain; C‐terminal PIR motifs), which could harbor additional glycosylphosphatidylinositol (GPI) addition‐signals. As representatives of the second group, Neurospora crassa (Nc) PIR‐1 (NCU04033) and PIR‐2 (NCU07569) were studied. Confocal microscopy of eGFP‐labeled Nc PIR‐1 and Nc PIR‐2 revealed they accumulate in apical plugs; additionally, PIR‐1 requires the Kex2 processing site for correct maturation and harbors a predicted GPI modification signal. Moreover, Nc Δpir‐1 and Δpir‐2 single mutants showed a growth rate similar to that of Nc wild‐type (WT), but the double mutant Nc Δpir‐1/Δpir‐2 grew significantly slower. Similarly, Nc Δpir‐1 and Nc Δpir‐2 were mildly sensitive to calcofluor white, although Nc Δpir‐1/Δpir‐2 double mutant was severely impaired. Despite the inverted architecture of Nc PIR‐1 and Nc PIR‐2, they maintain a role as cell wall stabilizers like classical yeast PIRs.

The fortune jack ( Seriola peruana ), a pelagic fish typically found along the Tropical Eastern Pacific, has been recorded in the northernmost Gulf of California (GC) region. The first record in the Upper Gulf and habitat expansion of S. peruana is reported based on the meristic, morphometric, and biological data of three specimens caught by local artisanal fishermen in April 2024. The lack of commercial value likely explains the region's absence of records for this species. The increased presence of S. peruana distribution in the Upper GC could have significant ecological implications, which warrants further fish habitat use and climate change research.

We present what we believe to be a novel proposal for the implementation of temporal-modes quantum gates based on the third-order nonlinear process of difference frequency generation in an integrated photonic circuit, which allows switching from one Pauli gate to another by tuning the phase difference between the two pump pulses (in case of the ${\sigma _x}$ and ${\sigma _y}$ Pauli gates) and between the two states comprising the basis of single temporal-modes qubits (in the case of the ${\sigma _z}$ Pauli gate). We demonstrate that our proposal enables the preparation of any single temporal-mode qubit and rotations on the Bloch sphere by changing externally controllable parameters. We also analyze the effects of fabrication errors on the predicted quantum gate fidelity, finding that, even if some waveguide parameter deviates from the design, slight tuning of pump wavelengths can lead to recovering high-fidelity values.

The proliferation of pelagic Sargassum in the tropical Atlantic since 2011 is causing considerable health and economic concerns as large amounts of this brown alga arrive and accumulate in coastal ecosystems of western Africa and of the greater Caribbean Sea every year. Many hypotheses have been proposed to explain the recurrence of Sargassum blooms since 2011 and their year-to-year variability. Among the hypotheses being debated about the origin and nutrient source to support the blooms are either: a) an increase in nutrient supply to the Atlantic Ocean via continental, or atmospheric inputs, or b) long-distance transport of a seed population during the North Atlantic Oscillation (NAO) event of 2009/2010 and stimulation of blooms in the tropical North Atlantic by nutrient supply primarily due to seasonal vertical mixing of the upper water column. The aim of this study is to address these alternate hypotheses. To this end, interannual numerical simulations (2002-2022) representing the transport, growth, and decay of pelagic Sargassum have been developed at basin scale. Our results confirm the role played by the NAO transport anomaly on the regime shift that occurred in 2010, and the primary role of vertical mixing in the tropical Atlantic as the primary nutrient source for the recurring blooms since 2011.

Seascape genomics facilitates integrative research on eco‐evolutionary forces, such as migration and natural selection, which shape genomic connectivity and structure and provide critical insights for conservation strategies. The green abalone (Haliotis fulgens) is distributed from California, United States, to Baja California Sur, Mexico, and exposed to a latitudinal environmental gradient in the California Current System. This study aimed to investigate genomic population structure and potential local adaptations of green abalone across its distribution. The green abalone exhibits a distinctive neutral genetic structuring influenced by geographic distance and marine currents rather than local adaptations. Analyses using 9100 neutral and 17 outlier SNPs revealed three distinct populations: the North group (California to Ensenada, Baja California), a population on Guadalupe Island, and the South group (coastal locations of the Baja California peninsula). The research underscores the significance of life history traits and larval dispersal in shaping genetic connectivity. Connectivity appears to be influenced by geographic distance on neutral genetic structure, overshadowing natural selection's role. Furthermore, no genome–environment associations to sea surface temperature values were found. Future research should integrate genetic data with ocean circulation modeling to better understand the mechanisms and outcomes of larval dispersal and genetic connectivity. This study emphasizes the importance of both local and binational (USA‐Mexico) conservation efforts, suggesting the development of SNP marker panels for traceability and management. Collaborative strategies could serve as models for binational conservation initiatives in other ecoregions, promoting sustainable management and conservation of green abalone populations and other exploited species across national borders.

Investigating the feeding ecology through the ontogenesis of highly migratory species such as the Pacific Bluefin tuna (PBFT; Thunnus orientalis) is difficult due to its extensive home range and cross‐oceanic migration. Here, we show the potential of conducting nitrogen stable isotope (δ¹⁵N) analyses in bulk tissue and amino acids (AAs) in consecutive eye lens laminae of PBFT to reconstruct the trophic life history for an individual tuna. The δ¹⁵Nbulk profiles between individuals caught in the wild and pen‐raised were compared. For all individuals, δ¹⁵Nbulk values increased with increasing eye lens diameter or fork length, and exhibited low variation among individual profiles despite tuna being captured in different months. Large δ¹⁵Nbulk shifts (6.8‰–8.5‰) were quantified between the first and last deposited laminae for each individual, suggesting major ontogenetic changes in either foraging areas or trophic position. AA δ¹⁵N values indicate that this highly migratory schooling predator switches feeding areas from lower to higher δ¹⁵N baseline values, reflecting feeding on both sides of the north Pacific, and tends to feed on prey of higher trophic position as it grows. Together, stable isotope analysis in bulk tissue and individual AAs in eye lens laminae could be a powerful approach to investigate changes in the foraging habitat and trophic status of highly migratory species.

Metabolic associated steatohepatitis characterized by lipid accumulation, inflammation and fibrosis, is a growing global health issue, contributing to severe liver-related mortality. With limited effective treatments available, there is an urgent...

Marine protists are key components of biogeochemical cycles and microbial food webs, which respond quickly to environmental factors. In the Gulf of Mexico (GoM), the Loop Current intensifies in summer and supplies the gulf with warm and oligotrophic waters. However, the cyclonic eddies within the GoM create favorable conditions for biological productivity by bringing nutrient-rich water to the subsurface layer. In this study, we investigated the response of the protist community to the regional physicochemical conditions, its spatial and temporal variability, the influence of mesoscale structures, and its ecological roles in the mixed layer (ML) and deep chlorophyll maximum (DCM). This is the first study to conduct a V9-18S rRNA gene survey for this community in the Mexican Exclusive Economic Zone of the GoM. The regional distribution, temporal changes, and mesoscale structures significantly affected the structure of the protist community in the ML. In contrast, only mesoscale structures significantly affected the protist community in the DCM. Different protist assemblages were also present between the ML and DCM, with Alveolata representing ∼60% of the community in both layers, followed by Haptophytes and Marine Stramenopiles in the ML; Pelagophytes and Radiolarians were the more prevalent taxa in the DCM. Finally, co-occurrence analyses revealed that competition, parasitism, and predation were the potential interactions shaping these communities at both depths.

A fundamental task in mobile robotics is keeping an intelligent agent under surveillance with an autonomous robot as it travels in the environment. This work studies a theoretical version of that problem involving one of the most popular vehicle platforms in robotics. In particular, we consider two identical Dubins cars moving on a plane without obstacles. One of them plays as the pursuer, and it is equipped with a limited field-of-view detection region modeled as a semi-infinite cone with its apex at the pursuer’s position. The pursuer aims to maintain the other Dubins car, which plays as the evader, as much time as possible inside its detection region. On the contrary, the evader wants to escape as soon as possible. In this work, employing differential game theory, we find the time-optimal motion strategies near the game’s end. The analysis of those trajectories reveals the existence of at least two singular surfaces: a Transition Surface (also known as a Switch Surface) and an Evader’s Universal Surface. We also found that the barrier’s standard construction produces a surface that partially lies outside the playing space.