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122 result(s) for "Narváez, Andrea"
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Performance of modified first-stage French Vertical Flow Constructed Wetlands under extreme operational conditions
Operation conditions considerably affect the removal efficiency of wastewater treatment systems, and yet we still lack data on how these systems function under extreme dilution rates and climatic conditions at high altitudes. Here, we applied two modified First-Stage French Vertical Flow Constructed Wetlands (FS-FVFCWs) for sewage treatment in Northern Tropical Andes. Specifically, within 18 months, we conducted a pilot-scale experiment at two hydraulic loading rates (HLRs) of 0.94 and 0.56 m d−1, representing 2.5 and 1.5 times the recommended design values, with two different feeding/resting periods to investigate the impact of HLRs and operational strategy on system performance. We found that chemical oxygen demand (COD) and total suspended solids (TSS) removal was satisfactory, with average values of 53 ± 18 and 69 ± 16%, respectively. Moreover, reducing HLRs resulted in higher removal efficiency for COD, from 46 ± 15 to 64 ± 15%, but had no impact on TSS removal, with 3 days of feeding and 6 days of resting. For an equal time of feeding and resting, COD and TSS removals were not affected by the modified HLR. These findings suggest that high HLRs can be applied to FS-FVFCW without compromising the system operation and obtaining satisfactory results, leading to opportunities to reduce areas and costs.
Preliminary assessment of beetle diversity in a fragmented landscape of the Ecuadorian tropical dry forest
Las alteraciones del paisaje pueden afectar los ensambles de escarabajos donde las especies sensibles pueden desaparecer y las poblaciones de especies altamente adaptadas pueden aumentar. Se evaluó la diversidad de escarabajos en un bosque restaurado y tierras de cultivo del bosque seco tropical de Ecuador. Se realizó trampas de caída y recolección manual en tres sitios; dos sitios con tierras de cultivo y un sitio con remanente de bosque secundario. Se usaron cuatro tipos de cebo para atraer escarabajos que se alimentaban de diferentes recursos para lograr una evaluación preliminar adecuada del ensamble de escarabajos. Este estudio es la primera aproximación a la caracterización de la comunidad de coleópteros en el bosque seco tropical de Manabí. Reportamos 64 morfoespecies asociadas con tierras productivas y bosques fragmentados y destacamos la presencia de algunos géneros resilientes como Canthon, Canthidium, Deltochilum y Euspilotus que se han adaptado con éxito a ecosistemas perturbados; por otro lado, Phyllophaga y Diabrotica también fueron detectados principalmente en el paisaje de cultivos. En general, presentamos una línea de base de la composición de escarabajos en un bosque secundario y tierras de cultivo, y brindamos información relevante para una evaluación adicional del cambio de uso del suelo en la región. Landscape alterations may affect beetle assemblages wherein sensitive species can disappear, and highly adapted species populations can increase. Beetle diversity in a restored forest and cropland was assessed in the tropical dry forest of Ecuador. Pitfall trapping and manual collection were performed in three sites: two sites with cropland and one site with secondary forest remnant. Four bait types were used to attract beetles feeding on different resources to achieve an adequate preliminary beetle assessment. This study is the first approach to characterizing the coleopteran community in the tropical dry forest of Manabí. We report 64 morpho-species associated with productive land and fragmented forests and highlight the occurrence of some resilient genera like Canthon, Canthidium, Deltochilum and Euspilotus that have successfully adapted to disturbed ecosystems; on the other hand, Phyllophaga and Diabrotica were also detected mainly in the crop landscape. Overall, present a baseline of the beetle assemblage composition in a secondary forest and cropland, and provide relevant information for further assessment of land use change in the region. 
Amphibians and reptiles of Isla Santay (Durán, Ecuador)
Amphibian and reptile diversity from Isla Santay (Durán, Ecuador) has been underestimated due to the lack of monitoring throughout the island. Historically, this island has also been affected by anthropic landscape changes which limit the occurrence of certain species and favors the dispersion of opportunistic or more tolerant species. Such species dynamics tend to be more evident on islands, since their isolation limits species' mobility. We present an updated checklist of the herpetofauna of Isla Santay Durán, Ecuador, and report for the first time the occurrence of two introduced species, Anolis sagrei Duméril & Bibron, 1837, Brown Anole, and Hemydactylus frenatus Duméril & Bibron, 1836.
Visual Signaling in the Semi-Fossorial Lizard Pholidobolus montium (Gymnophthalmidae)
It has been suggested that gymnophthalmids, like most semi-fossorial lacertoids, rely more in chemical cues to communicate, in comparison to other groups, like Iguanids, on which communication is mostly based on visual signaling. We present the first description of visual signaling in the Andean lizard Pholidobolusmontium (Gymnophthalmidae) and a complete ethogram based on ex situ observations (34 different types of behaviors including positions and simple movements). Through the design of conspecific stimulus experiments, we were able to recognize leg-waving as a visual signal, as it is only displayed in presence of conspecifics or in presence of a mirror and was one of first and most frequent displays in this context. We also detected other visual displays like neck-arching and tail-undulation which may also be relevant as visual signals. Based on our results, we propose that visual signaling is also possible in semi-fossorial lizards; however, further studies regarding chemical signal recognition and color detection are required to confirm our hypothesis.
Updated distribution of an alien frog species, Lithobates catesbeianus (Shaw, 1802), in Ecuador: new records of Bullfrog in the semideciduous lowland forest of western Ecuador
We report the occurrence of Lithobates catesbeianus (Shaw, 1802), Bullfrog, in a protected semidecidu-ous forest in the city of Guayaquil, Guayas, Ecuador and in a nearby wildlife management center. Bosqueira Pro-tected Forest is an isolated spot of diversity surrounded by urbanization, quarries, and highways. We found a juvenile Bullfrog in a water canal on the edge of the protected forest, near a private housing complex, and several tadpoles in an artificial pond in a wildlife management center located near the reserve. This is the first sighting of the invasive L. catesbeianus in a native ecosystem in Guayaquil. We also report the this species from, three other provinces of Ecuador, based on observations in iNaturalist. These records reinforce the ability of L. catesbeianus to adapt easily to varied environmental conditions and to disturbed areas. The invasion of L. catesbeianus towards semideciduous forest represents a new threat to biodiversity, particularly the endemic fauna, due to predation or competition. In future studies, it will be important to fully evaluate the Bullfrog diet and population status to esti-mate its impact on remnant forests of Guayaquil.
Feeding habits of Anolis sagrei, an introduced species, in urban ecosystems of Guayas Province
To maintain a stable population, an introduced species must be capable of exploiting varied resources and adapting to environmental conditions different from its native range. The brown anole (Anolis sagrei), one of the most prolific invasive species worldwide, is well established in Ecuador—especially in urban environments throughout Guayaquil and Samborondón (Guayas province). In this research, we describe the feeding habits of male and female brown anoles collected from six different sites: a regenerated wetland ecosystem and five city gardens. We dissected stomach contents in order to record the number and type of prey items, each classified to the lowest identifiable taxonomic category. Our results show that A. sagrei consumes a variety of prey items; Hymenoptera (mainly ants) represented the highest percentage of total gut contents from all sites. In addition, we found that A. sagrei also feeds on insects belonging to the families Cicadidae, Miridae, Scarabeidae, Chrysomelidae and Nitidulidae, all of which are considered to be agricultural pests. As such, we predict that A. sagrei could be an ideal model for biological control studies in urban environments throughout Guayas and perhaps beyond.
PET Imaging of Fructose Metabolism in a Rodent Model of Neuroinflammation with 6-18Ffluoro-6-deoxy-D-fructose
Fluorine-18 labeled 6-fluoro-6-deoxy-D-fructose (6-[18F]FDF) targets the fructose-preferred facilitative hexose transporter GLUT5, which is expressed predominantly in brain microglia and activated in response to inflammatory stimuli. We hypothesize that 6-[18F]FDF will specifically image microglia following neuroinflammatory insult. 6-[18F]FDF and, for comparison, [18F]FDG were evaluated in unilateral intra-striatal lipopolysaccharide (LPS)-injected male and female rats (50 µg/animal) by longitudinal dynamic PET imaging in vivo. In LPS-injected rats, increased accumulation of 6-[18F]FDF was observed at 48 h post-LPS injection, with plateaued uptake (60–120 min) that was significantly higher in the ipsilateral vs. contralateral striatum (0.985 ± 0.047 and 0.819 ± 0.033 SUV, respectively; p = 0.002, n = 4M/3F). The ipsilateral–contralateral difference in striatal 6-[18F]FDF uptake expressed as binding potential (BPSRTM) peaked at 48 h (0.19 ± 0.11) and was significantly decreased at one and two weeks. In contrast, increased [18F]FDG uptake in the ipsilateral striatum was highest at one week post-LPS injection (BPSRTM = 0.25 ± 0.06, n = 4M). Iba-1 and GFAP immunohistochemistry confirmed LPS-induced activation of microglia and astrocytes, respectively, in ipsilateral striatum. This proof-of-concept study revealed an early response of 6-[18F]FDF to neuroinflammatory stimuli in rat brain. 6-[18F]FDF represents a potential PET radiotracer for imaging microglial GLUT5 density in brain with applications in neuroinflammatory and neurodegenerative diseases.
Mating patterns and post-mating isolation in three cryptic species of the Engystomops petersi species complex
Determining the extent of reproductive isolation in cryptic species with dynamic geographic ranges can yield important insights into the processes that generate and maintain genetic divergence in the absence of severe geographic barriers. We studied mating patterns, propensity to hybridize in nature and subsequent fertilization rates, as well as survival and development of hybrid F1 offspring for three nominal species of the Engystomops petersi species complex in Yasuní National Park, Ecuador. We found at least two species in four out of six locations sampled, and 14.3% of the wild pairs genotyped were mixed-species (heterospecific) crosses. We also found reduced fertilization rates in hybrid crosses between E. petersi females and E. \"magnus\" males, and between E. \"magnus\" females and E. \"selva\" males but not in the reciprocal crosses, suggesting asymmetric reproductive isolation for these species. Larval development times decreased in F1 hybrid crosses compared to same species (conspecific) crosses, but we did not find significant reduction in larval survival or early metamorph survival. Our results show evidence of post-mating isolation for at least two hybrid crosses of the cryptic species we studied. The general decrease in fertilization rates in heterospecific crosses suggests that sexual selection and reinforcement might have not only contributed to the pattern of call variation and behavioral isolation we see between species today, but they may also contribute to further signal divergence and behavioral evolution, especially in locations where hybridization is common and fertilization success is diminished.
Association between uric acid and referable diabetic retinopathy in patients with type 2 diabetes
Plasmatic uric acid (UA) has been inconsistently associated with diabetic retinopathy (DR). Specific sight-threatening stages of DR have not been studied for their association with UA. Cross-sectional, comparative study. Between 2014 and 2018 we recruited 210 Mexican individuals > 18 years-old with type 2 diabetes (T2D). Clinical, ophthalmological and biochemical assessment was performed with standardized funduscopic examination. Certified readers classified DR stages. The association between DR and UA was assessed by multiple logistic regression analysis, calculating odds ratios (OR) and 95% CI, after adjustment for covariates. Two hundred and ten patients were included, 41 (19.5%) had referable DR. Subjects with referable (severe or worse) DR had longer diabetes duration, 22 (15–28) vs 15 (8–20) years ( P  < 0.01); higher levels of UA, 6.5 (5.8–8.1) vs 5.4 (4.5–6.6) mg/dL ( P  < 0.01); higher systolic blood pressure, 130 (120–140) vs 120 (110–130) mmHg ( P  < 0.01); higher diastolic blood pressure, 78.4 ± 9.7 vs 75.4 ± 9.2 mmHg ( P  = 0.03); and lower glomerular filtration rate , 54.1 (41.5–69.6) vs 87.3 (66.8–108.3) mL/min/1.73m 2 ( P  < 0.01) compared with those without referable DR. With multiple logistic regression, after adjustment, per each unit of change (mg/dL) in UA the probability of having referable DR increased 45% (OR = 1.45, 95% CI 1.12–1.87, P  < 0.01). When UA was evaluated as dichotomous variable, those with levels ≥ 7.8 mg/dL had almost two times (OR = 2.81, 95% CI 1.00–7.9., P  = 0.049) the probability of having referable DR compared with those with levels < 7.8 mg/dL. UA may contribute to the microvascular damage in retinal vessels and therefore hyperuricemia could be a therapeutic target to prevent DR progression.
First record of the invasive Brown Anole, Anolis sagrei Duméril & Bibron, 1837 (Squamata: Iguanidae: Dactyloinae), in South America
We report the first record of the invasive Brown Anole, Anolis sagrei Duméril & Bibron, 1837, in South America based on nine specimens from Samborondón, Guayas province, Ecuador. We also present some information related to the current distribution in Ecuador, and its possible impacts on native lizard species.