Water quality trends of streams in Puerto Rico: Evaluating 50 years of the Clean Water Act.

Water quality regulations entail a substantial commitment of resources from governments and private entities. It is important to continually evaluate the effectiveness of these regulations to ensure they are having the intended impact. In this paper, we evaluated nutrient data as indicators of primary productivity and dissolved oxygen (DO) concentrations and pH as response variables to assess historical water quality trends from 55 stations of Puerto Rico. The stations were divided into impaired versus non-impaired categories based on their historical total phosphorus (TP) mean concentration. Mean TP and total nitrogen (TN) concentrations were significantly higher in the impaired stations relative to the non-impaired stations. In contrast, DO mean concentrations and mean pH values were significantly lower in the impaired stations. A generalized additive mixed model was used to demonstrate temporal trends. A significant decrease in TP and TN concentrations was observed with time at the impaired stations. This was accompanied by significant increases in DO concentrations and pH. The non-impaired stations showed a marginal (statistically nonsignificant) decreasing trend with time. The large reductions in nutrient concentrations observed at the impaired stations seem to be related to the closure of several primary wastewater treatment plants (WWTPs) across the island. The conversion of abandoned crop agricultural lands into secondary forest in recent decades has resulted in small but significant decreases in TN (not TP) in receiving streams. We conclude that the Clean Water Act has promoted improvements in water quality in Puerto Rico by advancing upgrades in sanitary infrastructure and the regulation of point sources of pollution.

Beyond Correlation: Optimal Transport Metrics For Characterizing Representational Stability and Remapping in Neurons Encoding Spatial Memory.

Spatial representations in the entorhinal cortex (EC) and hippocampus (HPC) are fundamental to cognitive functions like navigation and memory. These representations, embodied in spatial field maps, dynamically remap in response to environmental changes. However, current methods, such as Pearson's correlation coefficient, struggle to capture the complexity of these remapping events, especially when fields do not overlap, or transformations are non-linear. This limitation hinders our understanding and quantification of remapping, a key aspect of spatial memory function. To address this, we propose a family of metrics based on the Earth Mover's Distance (EMD) as a versatile framework for characterizing remapping. Applied to both normalized and unnormalized distributions, the EMD provides a granular, noise-resistant, and rate-robust description of remapping. This approach enables the identification of specific cell types and the characterization of remapping in various scenarios, including disease models. Furthermore, the EMD's properties can be manipulated to identify spatially tuned cell types and to explore remapping as it relates to alternate information forms such as spatiotemporal coding. By employing approximations of the EMD, we present a feasible, lightweight approach that complements traditional methods. Our findings underscore the potential of the EMD as a powerful tool for enhancing our understanding of remapping in the brain and its implications for spatial navigation, memory studies and beyond.

Beyond correlation: optimal transport metrics for characterizing representational stability and remapping in neurons encoding spatial memory.

Introduction: Spatial representations in the entorhinal cortex (EC) and hippocampus (HPC) are fundamental to cognitive functions like navigation and memory. These representations, embodied in spatial field maps, dynamically remap in response to environmental changes. However, current methods, such as Pearson's correlation coefficient, struggle to capture the complexity of these remapping events, especially when fields do not overlap, or transformations are non-linear. This limitation hinders our understanding and quantification of remapping, a key aspect of spatial memory function. Methods: We propose a family of metrics based on the Earth Mover's Distance (EMD) as a versatile framework for characterizing remapping. Results: The EMD provides a granular, noise-resistant, and rate-robust description of remapping. This approach enables the identification of specific cell types and the characterization of remapping in various scenarios, including disease models. Furthermore, the EMD's properties can be manipulated to identify spatially tuned cell types and to explore remapping as it relates to alternate information forms such as spatiotemporal coding. Discussion: We present a feasible, lightweight approach that complements traditional methods. Our findings underscore the potential of the EMD as a powerful tool for enhancing our understanding of remapping in the brain and its implications for spatial navigation, memory studies and beyond.

Conocimiento sobre prevención del embarazo en adolescentes mexicanos / Knowledge about pregnancy prevention in Mexican adolescents

Resumen Objetivo: Establecer la relación entre el conocimiento sobre prevención de embarazo, edad de inicio de vida sexual, cantidad de métodos anticonceptivos utilizados alguna vez y características personales del adolescente como sexo, edad y escolaridad. Materiales y métodos: Estudio descriptivo, correlacional de corte transversal, participaron 2509 adolescentes mexicanos de 14 a 19 años de edad. Se emplearon los reactivos que miden el conocimiento en las dimensiones salud sexual, salud reproductiva y uso del condón de la escala psicométrica de conocimientos, actitudes y prácticas en salud sexual y salud reproductiva. Resultados: Se obtuvo una media de conocimiento sobre prevención de embarazo de 17.21 (DE = 4.72) de valores de 0-27. El conocimiento se relaciona significativamente con la edad del adolescente (r = 0.325; p = 0.01), con la cantidad de métodos anticonceptivos que utilizan (r = 0.210; p = 0.01) y una relación incipiente con la edad de IVS (r = 0.074; p = 0.01). El conocimiento es ligeramente mayor en las mujeres (M = 17.42; DE = 4.58) respecto a los hombres (M = 16.92; DE = 4.89), así como en los adolescentes universitarios (M = 18.71; DE = 4.19). Los adolescentes que utilizan 3 o más métodos anticonceptivos, mostraron mayor conocimiento (M = 19.46; DE = 4.11). Conclusiones: El conocimiento sobre prevención de embarazo es mayor conforme aumenta la edad, la edad de inicio de vida sexual y la escolaridad. Los hallazgos resultan de importancia para desarrollar estrategias de información sobre métodos anticonceptivos y salud sexual y reproductiva, de una forma accesible e igualitaria en mujeres y hombres desde edades tempranas y en escolaridad básica, con la intención de que el adolescente sea responsable desde el inicio de su vida sexual y de prevenir y postergar un embarazo a través del conocimiento como herramienta fundamental.

Abstract Objective: Establish the relationship between knowledge of pregnancy prevention, age of sexual debut, number of contraceptive methods ever used and personal characteristics of the adolescent such as sex, age and schooling. Materials and methods: A descriptive, cross-sectional, correlational, cross-sectional study, 2509 Mexican adolescents aged 14 to 19 years participated. The items measuring knowledge in the dimensions of sexual health, reproductive health and condom use of the psychometric scale of knowledge, attitudes and practices in sexual and reproductive health were used. Results: The mean knowledge of pregnancy prevention was 17.21 (SD = 4.72) from 0-27. Knowledge is significantly related to adolescent age (r = 0.325; p = 0.01), to the number of contraceptive methods used (r = 0.210; p = 0.01) and an incipient relationship with age at sexual debut (r = 0.074; p = 0.01). Knowledge is slightly higher in females (M = 17.42; SD = 4.58) relative to males (M = 16.92; SD = 4.89), as well as in college adolescents (M = 18.71; SD = 4.19). Adolescents using 3 or more contraceptive methods showed greater knowledge (M = 19.46; SD = 4.11). Conclusions: Knowledge about pregnancy prevention increases with age, age at sexual debut and schooling. The findings are important to develop information strategies on contraceptive methods and sexual and reproductive health, in an accessible and egalitarian way for women and men from an early age and in basic schooling, with the intention that the adolescent is responsible from the beginning of sexual life to prevent and postpone pregnancy through knowledge as a fundamental tool.

Is Haemoproteus gabaldoni a valid species? An approach from morphology and molecular tools applied to parasites of Anseriformes.

Currently, there are three recognized species of haemoproteids infecting Anseriformes: Haemoproteus nettionis, H. macrovacuolatus, and H. greineri. Unfortunately, genetic information associated with a morphotype is available only for H. macrovacuolatus. We recently found a parasite morphologically compatible with Haemoproteus gabaldoni, a species Bennet (1993) described in a Cairina moschata (Muscovy duck) from Venezuela. This species was synonymized to H. nettionis by Valkiunas (2005), arguing not enough morphological differentiation between them; it was said that H. greineri could be as well a synonym of H. nettionis. In this study, we aimed to provide evidence to determine if Haemoproteus gabaldoni is a different species of H. nettionis and help to clarify other species status. We first performed morphological and morphometrical analyses and compared this information against the parahapantotypes of H. greineri, H. gabaldoni and material diagnosed as H. nettionis provided by the International Reference center for Avian Haematozoa (IRCAH), and H. macrovacuolatus from the Host-Parasite Relationship Study Group (GERPH, in Spanish Grupo de Estudio Relación Parásito Hospedero) biological collection. We used Principal Component Analysis (PCA) of dimensionless standard morphometrical variables from gametocytes. Furthermore, we amplified a small fragment of cytochrome b (cyt b) to compare the sequence with information in GenBank and Malavi through phylogenetic analyses and haplotype networks. PCA analyses revealed the presence of three distinct groups in the samples studied, supported in the morphological traits of each parasite species analyzed; phylogenetic analyses grouped parasite lineages separately according to the host and continent of provenance. Such results indicate that, H. gabaldoni, is a different species from H. nettionis. One more time, it is demonstrated the importance of linking barcode surveys to morphological studies. Finally, it is highlighted the importance of biological collections as repositories of worldwide biodiversity.

Comprehensive dataset of shotgun metagenomes from oxygen stratified freshwater lakes and ponds.

Stratified lakes and ponds featuring steep oxygen gradients are significant net sources of greenhouse gases and hotspots in the carbon cycle. Despite their significant biogeochemical roles, the microbial communities, especially in the oxygen depleted compartments, are poorly known. Here, we present a comprehensive dataset including 267 shotgun metagenomes from 41 stratified lakes and ponds mainly located in the boreal and subarctic regions, but also including one tropical reservoir and one temperate lake. For most lakes and ponds, the data includes a vertical sample set spanning from the oxic surface to the anoxic bottom layer. The majority of the samples were collected during the open water period, but also a total of 29 samples were collected from under the ice. In addition to the metagenomic sequences, the dataset includes environmental variables for the samples, such as oxygen, nutrient and organic carbon concentrations. The dataset is ideal for further exploring the microbial taxonomic and functional diversity in freshwater environments and potential climate change impacts on the functioning of these ecosystems.

Chemogenetic attenuation of neuronal activity in the entorhinal cortex reduces Aß and tau pathology in the hippocampus.

High levels of the amyloid-beta (Aß) peptide have been shown to disrupt neuronal function and induce hyperexcitability, but it is unclear what effects Aß-associated hyperexcitability may have on tauopathy pathogenesis or propagation in vivo. Using a novel transgenic mouse line to model the impact of human APP (hAPP)/Aß accumulation on tauopathy in the entorhinal cortex-hippocampal (EC-HIPP) network, we demonstrate that hAPP overexpression aggravates EC-Tau aggregation and accelerates pathological tau spread into the hippocampus. In vivo recordings revealed a strong role for hAPP/Aß, but not tau, in the emergence of EC neuronal hyperactivity and impaired theta rhythmicity. Chronic chemogenetic attenuation of EC neuronal hyperactivity led to reduced hAPP/Aß accumulation and reduced pathological tau spread into downstream hippocampus. These data strongly support the hypothesis that in Alzheimer's disease (AD), Aß-associated hyperactivity accelerates the progression of pathological tau along vulnerable neuronal circuits, and demonstrates the utility of chronic, neuromodulatory approaches in ameliorating AD pathology in vivo.

Tau Pathology Induces Excitatory Neuron Loss, Grid Cell Dysfunction, and Spatial Memory Deficits Reminiscent of Early Alzheimer's Disease.

The earliest stages of Alzheimer's disease (AD) are characterized by the formation of mature tangles in the entorhinal cortex and disorientation and confusion when navigating familiar places. The medial entorhinal cortex (MEC) contains specialized neurons called grid cells that form part of the spatial navigation system. Here we show in a transgenic mouse model expressing mutant human tau predominantly in the EC that the formation of mature tangles in old mice was associated with excitatory cell loss and deficits in grid cell function, including destabilized grid fields and reduced firing rates, as well as altered network activity. Overt tau pathology in the aged mice was accompanied by spatial memory deficits. Therefore, tau pathology initiated in the entorhinal cortex could lead to deficits in grid cell firing and underlie the deterioration of spatial cognition seen in human AD.

Neuronal activity enhances tau propagation and tau pathology in vivo.

Tau protein can transfer between neurons transneuronally and trans-synaptically, which is thought to explain the progressive spread of tauopathy observed in the brain of patients with Alzheimer's disease. Here we show that physiological tau released from donor cells can transfer to recipient cells via the medium, suggesting that at least one mechanism by which tau can transfer is via the extracellular space. Neuronal activity has been shown to regulate tau secretion, but its effect on tau pathology is unknown. Using optogenetic and chemogenetic approaches, we found that increased neuronal activity stimulates the release of tau in vitro and enhances tau pathology in vivo. These data have implications for disease pathogenesis and therapeutic strategies for Alzheimer's disease and other tauopathies.

Human APOE4 increases microglia reactivity at Aß plaques in a mouse model of Aß deposition.

BACKGROUND: Having the apolipoprotein E4 (APOE-ϵ4) allele is the strongest genetic risk factor for the development of Alzheimer's disease (AD). Accumulation of amyloid beta (Aß) in the brain is influenced by APOE genotype. Transgenic mice co-expressing five familial AD mutations (5xFAD) in the presence of human APOE alleles (ϵ2, ϵ3 or ϵ4) exhibit APOE genotype-specific differences in early Aß accumulation, suggesting an interaction between APOE and AD pathology. Whether APOE genotype affects Aß-plaque-associated neuroinflammation remains unclear. In the current study, we address the role of APOE genotype on Aß-associated microglial reactivity in the EFAD transgenic mouse model. METHODS: We analyzed Aß-induced glial activation in the brains of 6-month-old EFAD transgenic mice (E2FAD, E3FAD and E4FAD). Region-specific morphological profiles of Aß plaques in EFAD brain sections were compared using immunofluorescence staining. We then determined the degree of glial activation in sites of Aß deposition while comparing levels of the inflammatory cytokine Interleukin-1ß (IL-1ß) by ELISA. Finally, we quantified parameters of Aß-associated microglial reactivity using double-stained EFAD brain sections. RESULTS: Characterization of Aß plaques revealed there were larger and more intensely stained plaques in E4FAD mice relative to E2FAD and E3FAD mice. E4FAD mice also had a greater percentage of compact plaques in the subiculum than E3FAD mice. Reactive microglia and dystrophic astrocytes were prominent in EFAD brains, and primarily localized to two sites of significant Aß deposition: the subiculum and deep layers of the cortex. Cortical levels of IL-1ß were nearly twofold greater in E4FAD mice relative to E3FAD mice. To control for differences in levels of Aß in the different EFAD mice, we analyzed the microglia within domains of specific Aß deposits. Morphometric analyses revealed increased measures of microglial reactivity in E4FAD mice, including greater dystrophy, increased fluorescence intensity and a higher density of reactive cells surrounding cortical plaques, than in E3FAD mice. CONCLUSIONS: In addition to altering morphological profiles of Aß deposition, APOE genotype influences Aß-induced glial activation in the adult EFAD cortex. These data support a role for APOE in modulating Aß-induced neuroinflammatory responses in AD progression, and support the use of EFAD mice as a suitable model for mechanistic studies of Aß-associated neuroinflammation.

Human APOE genotype affects intraneuronal Aß1-42 accumulation in a lentiviral gene transfer model.

Intraneuronal accumulation of ß-amyloid (Aß)42 is one of the earliest pathological events in humans and in animal models of Alzheimer's disease (AD). Apolipoprotein E 4 (APOE4) is the major identified genetic risk factor for late-onset AD, with Aß deposition beginning earlier in apoE4-positive subjects. To directly determine the effects of APOE genotype on intraneuronal accumulation of Aß1-42 at the onset of AD pathogenesis, we introduced lentiviral Aß1-42 into the cortex of APOE targeted replacement (TR) mice at the age of 8-9 months. We demonstrated a significant isoform-dependent effect of human APOE, with dramatically enhanced intracellular Aß1-42 deposits in the cerebral cortex of APOE4-TR mice 2 weeks after injection. Double-immunofluorescent staining showed that intracellular accumulation of lentiviral Aß1-42 was mainly present in neurons, localized to late endosomes/lysosomes. This intraneuronal accumulation of Aß1-42 correlated with increased tau phosphorylation and cell death in the ipsilateral cortex around the injection site. Aß1-42 was also observed in microglia, but not in astrocytes. Quantitative analysis revealed more neurons with Aß1-42 while less microglia with Aß1-42 nearest to the injection site of Aß1-42 lentivirus in APOE4-TR mice. Finally, apoE was present in neurons of the ipsilateral cortex of APOE-TR mice at 2 weeks after lentivirus injection, in addition to astrocytes and microglia in both the ipsilateral and contralateral cerebral cortex. Taken together, these results demonstrate that apoE4 tips the balance of the glial and neuronal Aß toward the intraneuronal accumulation of Aß.

Young APOE4 targeted replacement mice exhibit poor spatial learning and memory, with reduced dendritic spine density in the medial entorhinal cortex.

The apolipoprotein E4 (APOE-ε4) allele is the strongest genetic risk factor for developing late-onset Alzheimer's disease, and may predispose individuals to Alzheimer's-related cognitive decline by affecting normal brain function early in life. To investigate the impact of human APOE alleles on cognitive performance in mice, we trained 3-mo-old APOE targeted replacement mice (E2, E3, and E4) in the Barnes maze to locate and enter a target hole along the perimeter of the maze. Long-term spatial memory was probed 24 h and 72 h after training. We found that young E4 mice exhibited significantly impaired spatial learning and memory in the Barnes maze compared to E3 mice. Deficits in spatial cognition were also present in a second independent cohort of E4 mice tested at 18 mo of age. In contrast, cognitive performance in the hidden platform water maze was not as strongly affected by APOE genotype. We also examined the dendritic morphology of neurons in the medial entorhinal cortex of 3-mo-old TR mice, neurons important to spatial learning functions. We found significantly shorter dendrites and lower spine densities in basal shaft dendrites of E4 mice compared to E3 mice, consistent with spatial learning and memory deficits in E4 animals. These findings suggest that human APOE-ε4 may affect cognitive function and neuronal morphology early in life.