A New Method for Low Density Distribution Modeling and Near Threatened Species: The Study Case of Plectrohyla Guatemalensis.

We introduce a model that can be used for the description of the distribution of species when there is scarcity of data, based on our previous work (Ballesteros et al. J Math Biol 85(4):31, 2022). We address challenges in modeling species that are seldom observed in nature, for example species included in The International Union for Conservation of Nature's Red List of Threatened Species (IUCN 2023). We introduce a general method and test it using a case study of a near threatened species of amphibians called Plectrohyla Guatemalensis (see IUCN 2023) in a region of the UNESCO natural reserve "Tacaná Volcano", in the border between Mexico and Guatemala. Since threatened species are difficult to find in nature, collected data can be extremely reduced. This produces a mathematical problem in the sense that the usual modeling in terms of Markov random fields representing individuals associated to locations in a grid generates artificial clusters around the observations, which are unreasonable. We propose a different approach in which our random variables describe yearly averages of expectation values of the number of individuals instead of individuals (and they take values on a compact interval). Our approach takes advantage of intuitive insights from environmental properties: in nature individuals are attracted or repulsed by specific features (Ballesteros et al. J Math Biol 85(4):31, 2022). Drawing inspiration from quantum mechanics, we incorporate quantum Hamiltonians into classical statistical mechanics (i.e. Gibbs measures or Markov random fields). The equilibrium between spreading and attractive/repulsive forces governs the behavior of the species, expressed through a global control problem involving an energy operator.

Bayesian and network models with covariate effects for predicting heating energy demand.

The spatial effect is an element presented in many geostatistical works and it should be incorporated into studies regarding the heating energy demand of residential building stocks. The most common approaches have been made by simple descriptive statistics or using analyses by Markov random fields. In this work, we propose two different methods. First, the Stochastic Partial Differential Equation with the Integrated Nested Laplace Approximation to model the variable heating energy demand in Castellón de la Plana, Spain also considering covariates and the spatial effect. Second, simulated street networks for analysing data. We describe and take advantage of the Bayesian methodology in the modelling process in all the scenarios, including covariates and the possibility of creating a simulated street network with the data for the modelling issue. Our results show that the spatial location of the building is a crucial element to study the heating energy demand using both methodologies.

Risk transfer from a megacity to a peri-urban agricultural community: wastewater reuse and effects on groundwater quality.

Urban wastewater is a resource that can be reused, but its management must be carefully executed, considering its potential impact on public and environmental health. Unfortunately, marked differences in the quality of treatment, management, collection, and the monitoring of wastewater exist among low-, middle-, and high-income countries. This is the case of the Mezquital Valley, a semi-rural area that is composed of agricultural and industrial communities on the outskirts of Mexico City. For over 100 years, wastewater from Mexico City and its areas of conurbation has been sent to the Mezquital Valley, with few studies having been conducted to assess the existence and severity of bacterial and pathogen infiltration into the local aquifer. In this research, we present an assessment of wastewater infiltration transported from Mexico City, used for irrigation, with potential infiltration into the Mezquital Valley aquifer. We utilized stable isotope analysis of deuterium and oxygen-18 to determine whether a mixture of untreated wastewater from the Mexico City Metropolitan Area (MCMA) flows into the Mezquital aquifer. Also, tests for adenovirus, rotavirus, fecal coliform, fecal enterococci, Giardia lamblia, and Cryptosporidium parvum were employed to determine the presence of fecal indicators and pathogens in different water sources in the study area. The results show the presence of indicators and pathogens in local wells used as water supply in Mezquital Valley. The presence of such indicators suggests that pathogens can reach the water consumed by the inhabitants, posing a hazard to persons exposed to these waters during their normal daily-life activities.

Association between the New COVID-19 Cases and Air Pollution with Meteorological Elements in Nine Counties of New York State.

The principal objective of this article is to assess the possible association between the number of COVID-19 infected cases and the concentrations of fine particulate matter (PM2.5) and ozone (O3), atmospheric pollutants related to people's mobility in urban areas, taking also into account the effect of meteorological conditions. We fit a generalized linear mixed model which includes spatial and temporal terms in order to detect the effect of the meteorological elements and COVID-19 infected cases on the pollutant concentrations. We consider nine counties of the state of New York which registered the highest number of COVID-19 infected cases. We implemented a Bayesian method using integrated nested Laplace approximation (INLA) with a stochastic partial differential equation (SPDE). The results emphasize that all the components used in designing the model contribute to improving the predicted values and can be included in designing similar real-world data (RWD) models. We found only a weak association between PM2.5 and ozone concentrations with COVID-19 infected cases. Records of COVID-19 infected cases and other covariates data from March to May 2020 were collected from electronic health records (EHRs) and standard RWD sources.

Reliability Evaluation of the Data Acquisition Potential of a Low-Cost Climatic Network for Applications in Agriculture.

Temperature, humidity and precipitation have a strong influence on the generation of diseases in different crops, especially in vine. In recent years, advances in different disciplines have enabled the deployment of sensor nodes on agricultural plots. These sensors are characterised by a low cost and so the reliability of the data obtained from them can be compromised, as they are built from low-confidence components. In this research, two studies were carried out to determine the reliability of the data obtained by different SEnviro nodes installed in vineyards. Two networks of meteorological stations were used to carry out these studies, one official and the other professional. The first study was based on calculating the homogenisation of the data, which was performed using the Climatol tool. The second study proposed a similarity analysis using cross-correlation. The results showed that the low-cost node can be used to monitor climatic conditions in an agricultural area in the central zone of the province of Castelló (Spain) and to obtain reliable observations for use in previously published fungal disease models.

Effect of Nicotine on CYP2B1 Expression in a Glioma Animal Model and Analysis of CYP2B6 Expression in Pediatric Gliomas.

Cyclophosphamide (CPA) is a pro-drug commonly used in the chemotherapeutic schemes for glioma treatment but has high toxicity and the side effects include brain damage and even death. Since CPA is activated mainly by CY2B6, over-expression of the enzyme in the tumor cells has been proposed to enhance CPA activation. In this study, we explored the induction of the Cyp2b1 (homologous to CYP2B6) by nicotine in an animal rat model with glioma. Gene expression and protein levels were analyzed by RT-PCR and Western blot. Nicotine treatment increased CYP2B1 protein levels in the healthy animals' brain tissue. In the brain tissue of animals with glioma, the CYP2B1 showed a high expression, even before nicotine treatment. Nicotine did not increase significantly the CYP2B1 protein expression in the tumor, but increased its expression in the tumor vicinity, especially around blood vessels in the cortex. We also explored CY2B6 expression in glioma samples derived from pediatric patients. Tumor tissue showed a variable expression of the enzyme, which could depend on the tumor malignancy grade. Induction of the CYP2B6 in pediatric gliomas with lower expression of the enzyme, could be an alternative to improve the antitumoral effect of CPA treatment.

FRNA Bacteriophages as Viral Indicators of Faecal Contamination in Mexican Tropical Aquatic Systems.

A particular challenge to water safety in populous intertropical regions is the lack of reliable faecal indicators to detect microbiological contamination of water, while the numerical relationships of specific viral indicators remain largely unexplored. The aim of this study was to investigate the numerical relationships of FRNA-bacteriophage genotypes, adenovirus 41, and human adenoviruses (HADV) in Mexican surface water systems to assess sewage contamination. We studied the presence of HADV, HADV41 and FRNA bacteriophage genotypes in water samples and quantified by qPCR and RT-qPCR. Virus and water quality indicator variances, as analyzed by principal component analysis and partial least squared regression, followed along the major percentiles of water faecal enterococci. FRNA bacteriophages adequately deciphered viral and point source water contamination. The strongest correlation for HADV was with FRNA bacteriophage type II, in water samples higher than the 50th percentiles of faecal enterococci, thus indicating urban pollution. FRNA bacteriophage genotypes I and III virus indicator performances were assisted by their associations with electrical conductivity and faecal enterococci. In combination, our methods are useful for inferring water quality degradation caused by sewage contamination. The methods used have potential for determining source contamination in water and, specifically, the presence of enteric viruses where clean and contaminated water have mixed.

Microbial Indicators, Opportunistic Bacteria, and Pathogenic Protozoa for Monitoring Urban Wastewater Reused for Irrigation in the Proximity of a Megacity.

In Latin America and the Caribbean, with a population of approximately 580 million inhabitants, less than 20 % of wastewater is treated. Megacities in this region face common challenges and problems related with water quality and sanitation, which require urgent actions, such as changes in the sustainable use of water resources. The Mexico City Metropolitan Area is one of the most populous urban agglomerations in the world, with over 20 million inhabitants, and is no exception to the challenges of sustainable water management. For more than 100 years, wastewater from Mexico City has been transported north to the Mezquital Valley, which is ranked as the largest wastewater-irrigated area in the world. In this study, bacteria and pathogenic protozoa were analyzed to determine the association between the presence of such microorganisms and water types (WTs) across sampling sites and seasons in Mexico City and the Mezquital Valley. Our results show a difference in microbiological water quality between sampling sites and WTs. There is no significant interaction between sampling sites and seasons in terms of bacterial concentration, demonstrating that water quality remains constant at each site regardless of whether it is the dry or the rainy season. The results illustrate the quantity of these microorganisms in wastewater, provide a current diagnosis of water quality across the area which could affect the health of residents in both Mexico City and the Mezquital Valley, and demonstrate the need to transition in the short term to treat wastewater from a local to a regional scale.

Drinking water quality in a Mexico city university community: perception and preferences.

A transversal study was conducted at the University City campus of the National Autonomous University of Mexico (UNAM) in Mexico City, with the goal of estimating the university community preference for drinking either tap water or bottled water and the reasons for their selection. A representative sample of three university community subpopulations (students, workers/administrative staff, and academic personnel) were interviewed with respect to their water consumption habits. The results showed that 75% of the university community drinks only bottled water and that the consumption of tap water is low. The interviewees responded that the main reason for this preference is the organoleptic features of tap water independent of quality. In general, the participants in this study do not trust the quality of the tap water, which could be caused by the facilities that distribute bottled water encouraging a general disinterest in learning about the origin and management of the tap water that is distributed on campus.

Final opportunity to rehabilitate an urban river as a water source for Mexico City.

The aim of this study was to evaluate the amount and quality of water in the Magdalena-Eslava river system and to propose alternatives for sustainable water use. The system is the last urban river in the vicinity of Mexico City that supplies surface water to the urban area. Historical flow data were analyzed (1973-2010), along with the physicochemical and bacteriological attributes, documenting the evolution of these variables over the course of five years (2008-2012) in both dry and rainy seasons. The analyses show that the flow regime has been significantly altered. The physicochemical variables show significant differences between the natural area, where the river originates, and the urban area, where the river receives untreated wastewater. Nutrient and conductivity concentrations in the river were equivalent to domestic wastewater. Fecal pollution indicators and various pathogens were present in elevated densities, demonstrating a threat to the population living near the river. Estimates of the value of the water lost as a result of mixing clean and contaminated water are presented. This urban river should be rehabilitated as a sustainability practice, and if possible, these efforts should be replicated in other areas. Because of the public health issues and in view of the population exposure where the river flows through the city, the river should be improved aesthetically and should be treated to allow its ecosystem services to recover. This river represents an iconic case for Mexico City because it connects the natural and urban areas in a socio-ecological system that can potentially provide clean water for human consumption. Contaminated water could be treated and reused for irrigation in one of the green areas of the city. Wastewater treatment plants and the operation of the existing purification plants are urgent priorities that could lead to better, more sustainable water use practices in Mexico City.

Spatial structure of the abiotic environment and its association with sapling community structure and dynamics in a cloud forest.

Analyzing the relationship between the spatial structures of environmental variables and of the associated seedling and sapling communities is crucial to understanding the regeneration processes in forest communities. The degree of spatial structuring (i.e., spatial autocorrelation) of environmental and sapling community variables in the cloud forest of Teipan, S Mexico, were analyzed at a 1-ha scale using geostatistical analysis; after fitting semivariogram models for each set of variables, the association between the two sets was examined through cross-variograms. Kriging maps of the sapling community variables (density, cover, species richness, and mortality and recruitment rates) were obtained through conditional simulation method. Canopy openness, total solar radiation, litter depth, soil temperature and soil moisture were spatially structured, as were sapling density, species richness and sapling mortality rate. Mean range in semivariograms for environmental and sapling community variables were 13.14 ± 3.67 and 12.68 ± 5.71 m (±SE), respectively. The spatial structure of litter depth was negatively associated with the spatial structures of sapling density, species richness, and sapling community cover; in turn, the spatial structure of soil moisture was positively associated with the spatial structure of recruitment rate. These associations of the spatial structures of abiotic and sapling community variables suggest that the regeneration processes in this cloud forest is driven by the existence of different microsites, largely characterized by litter depth variations, across which saplings of tree species encounter a range of opportunities for successful establishment and survival.

Factors controlling the abundance and size distribution of the phototrophic ciliate Myrionecta rubra in open waters of the North Atlantic.

Myrionecta rubra, a ubiquitous planktonic ciliate, has received much attention due to its wide distribution, occurrence as a red tide organism, and unusual cryptophyte endosymbiont. Although well studied in coastal waters, M. rubra is poorly examined in the open ocean. In the Irminger Basin, North Atlantic, the abundance of M. rubra was 0-5 cells/ml, which is low compared with that found in coastal areas. Distinct patchiness (100 km) was revealed by geostatistical analysis. Multiple regression indicated there was little relationship between M. rubra abundance and a number of environmental factors, with the exception of temperature and phytoplankton biomass, which influenced abundance in the spring. We also improve on studies that indicate distinct size classes of M. rubra; we statistically recognise four significantly distinct width classes (5-16, 12-23, 18-27, 21-33 microm), which decrease in abundance with increasing size. A multinomial logistic regression revealed the main variable correlated with this size distribution was ambient nitrate concentration. Finally, we propose a hypothesis for the distribution of sizes, involving nutrients, feeding, and dividing of the endosymbiont.

Bioconversion of lutein using a microbial mixture--maximizing the production of tobacco aroma compounds by manipulation of culture medium.

The generation of aroma compounds by carotenoid cleavage in the 9-10 position was studied, due to the importance of these compounds in the flavor and fragrance industry. The bioconversion of the carotenoid lutein to C(13) norisoprenoids utilizing a microbial mixture composed of Trichosporon asahii and Paenibacillus amylolyticus was carried out by a fermentation process. Applying an experimental design methodology, the effects of nutritional factors on the production of aroma compounds present in the tobacco profile were studied. After an assessment of the significance of each nutritional factor, the levels of the variables yielding the maximum response were calculated. Glucose, tryptone, and yeast extract exerted a strong negative effect over the objective function, with glucose being the strongest. Lutein possessed a positive effect over the tobacco aroma production, while sodium chloride and trace elements showed no influence over the process. The yield attained after culture medium manipulation was almost ten-fold higher, compared with the base medium; and the aroma mixture was characterized as: 7,8-dihydro-beta-ionol (95.2%), 7,8-dihydro-beta-ionone (3.7%), and beta-ionone (1.1%).

[Environmental variables and abundance of eggs of Anchoa mitchilli (Pisces: Engraulidae) in Tamiahua lagoon, Mexico]. / Variables ambientales y abundancia de los huevos de Anchoa mitchilli (Pisces: Engraulidae) en la laguna de Tamiahua, México.

Egg abundance of Anchoa mitchilli was studied in Laguna de Tamiahua, Veracruz during three annual cycles (84-85, 85-86 and 86-87). Our goal was to detect areas and seasons with high egg abundance and the possible association of such areas and seasons with covariates such as temperature, salinity, transparency, depth, location, season and year. The association was tested statistically using a Generalized Linear Model (GLM) with Gamma type error. The results suggest that not all the covariates considered have a significant effect on egg abundance (Student's T, p > 0.005). The significant effects show the presence of a seasonal component and that the effect of salinity on egg abundance is conditional to location. High average egg abundances for the three annual cycles were observed during summer. The presence of significant interactions (Student's T, p < 0.05) during the last two annual cycles shows that the variability of egg abundance is associated to surface temperature and salinity, conditionally to year.