Hydroclimate variability in Central America during the Holocene inferred from lacustrine sediments in Lake Izabal, eastern Guatemala

Holocene hydroclimate reconstructions have contributed to our understanding of the mechanisms controlling precipitation in Central America. Recent hydroclimate proxy records from the region, however, have revealed considerable spatiotemporal complexity in precipitation variability. This complexity is hypothesized to result from the interaction between multiple oceanic-atmospheric processes that converge in the region. This project analyzed three sediment cores from Lake Izabal, eastern lowland Guatemala, with the goal of understanding changes in precipitation, lake productivity, and lake water chemistry during the Holocene. Our proxy results indicate that precipitation in the region increased from the early to the middle Holocene, when Lake Izabal became a meromictic lake following a marine incursion. Anoxic bottom waters lasted ~3,500 years, preserving 2,186 mm-scale dark and light laminae couplets that are distinctly different in color, composition, and texture. At ~4,800 calibrated years before present (cal yr BP), Lake Izabal became a polymictic lake, and precipitation in the region stabilized, remaining high until ~1,200 cal yr BP, with an abrupt decrease in precipitation thereafter. Our findings indicate that Lake Izabal is highly sensitive to changes in Caribbean sea level and Caribbean sea-surface temperatures, the former controlling lake water chemistry and the latter controlling precipitation. Our results also add to new hydroclimate proxy data from the region, highlighting the complexity in precipitation variability in the area. Additional paleoclimate proxy records from Central America are needed to improve our understanding of how global warming will affect environmental conditions and regional hydroclimate variability --Abstract, page iv

Sedimentological And Geochemical Characterization Of A Varved Sediment Record From The Northern Neotropics

Annually resolved sedimentological records (including annual varves) can be used to develop precise chronologies for key climatic and tectonic events. Varved records, however, are most common in high latitude lakes, resulting in a spatial bias with respect to annually resolved records in tropical regions. Here we report on the sedimentology of two sediment cores from Lake Izabal, eastern Guatemala, that contain a well-preserved thinly laminated section spanning ca. 2200 years of the mid-Holocene. We integrate radiocarbon age-depth modeling, sedimentological observations, laminae counting, µX-ray fluorescence scanning, and multivariate statistical analyses to constrain the nature and chronology of the laminations. Our sedimentological and geochemical results suggest that the alternating clastic (dark) and biogenic (light) laminae couplets were deposited annually. Dark laminae are characterized by an abundance of detrital grains, organic detritus, total organic carbon, and terrigenic elements, and most likely formed during times of increased discharge during the rainy season. In contrast, light laminae are characterized by a decrease in detrital grains and total organic carbon, and an increase in biogenic silica constituents, and were likely deposited at times of increased lake productivity during the dry season. We compare a floating varve chronology that spans ca. 2200 years with three radiocarbon-based age-depth models. Consistency between the varve chronology and one of the models partially supports the annual character of the laminated section in Lake Izabal. This laminated section, one of the first annually resolved sedimentological records from Central America, can help explore mid-Holocene hydroclimate variability and regional tectonic processes in this understudied region

Tetrabenazine versus deutetrabenazine for Huntington's disease : twins or distant cousins?

© 2017 The Authors. Movement Disorders Clinical Practice published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Background: Tetrabenazine is the only US Food and Drug Administration‐approved drug for Huntington's disease, and deutetrabenazine was recently tested against placebo. A switching‐trial from tetrabenazine to deutetrabenazine is underway, but no head‐to‐head, blinded, randomized controlled trial is planned. Using meta‐analytical methodology, the authors compared these molecules. Methods: RCTs comparing tetrabenazine or deutetrabenazine with placebo in Huntington's disease were searched. The authors assessed the Cochrane risk‐of‐bias tool, calculated indirect treatment comparisons, and applied the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. Results: The evidence network for this report comprised 1 tetrabenazine trial and 1 deutetrabenazine trial, both against placebo. Risk of bias was moderate in both. Participants in the tetrabenazine and deutetrabenazine trials did not differ significantly on motor scores or adverse events. Depression and somnolence scales significantly favored deutetrabenazine. Conclusion: There is low‐quality evidence that tetrabenazine and deutetrabenazine do not differ in efficacy or safety. It is important to note that these results are likely to remain the only head‐to‐head comparison between these 2 compounds in Huntington's disease.info:eu-repo/semantics/publishedVersio

Diseño de 1,500.00 metros de pavimento articulado por método AASHTO 93 y drenaje menor en el barrio San José, Santo Tomas, Chontales.

Esta propuesta consiste en determinar las propiedades mecánicas del suelo, diseñar las diferentes capas que componen la estructura del pavimento y su respectivo drenaje menor, de 1,500.00 metros de calle a través del método AASHTO 93

Effects of seagrasses and algae of the Caulerpa family on hydrodynamics and particle-trapping rates

The widespread decline of seagrass beds within the Mediterranean often results in the replacement of seagrasses by opportunistic green algae of the Caulerpa family. Because Caulerpa beds have a different height, stiffness and density compared to seagrasses, these changes in habitat type modify the interaction of the seafloor with hydrodynamics, influencing key processes such as sediment resuspension and particle trapping. Here, we compare the effects on hydrodynamics and particle trapping of Caulerpa taxifolia, C. racemosa, and C. prolifera with the Mediterranean seagrasses Cymodocea nodosa and Posidonia oceanica. All macrophyte canopies reduced near-bed volumetric flow rates compared to bare sediment, vertical profiles of turbulent kinetic energy revealed peak values around the top of the canopies, and maximum values of Reynolds stress increased by a factor of between 1.4 (C. nodosa) and 324.1 (P. oceanica) when vegetation was present. All canopies enhanced particle retention rates compared to bare sediment. The experimental C. prolifera canopy was the most effective at particle retention (m2 habitat); however, C. racemosa had the largest particle retention capacity per structure surface area. Hence, in terms of enhancing particle trapping and reducing hydrodynamic forces at the sediment surface, Caulerpa beds provided a similar or enhanced function compared to P.oceanica and C. nodosa. However, strong seasonality in the leaf area index of C. racemosa and C. taxifolia within the Mediterranean, combined with a weak rhizome structure, suggests that sediments maybe unprotected during winter storms, when most erosion occurs. Hence, replacement of seagrass beds with Caulerpa is likely to have a major influence on annual sediment dynamics at ecosystem scales.This research was funded by the European Network of Excellence ‘‘Marine Biodiversity and Ecosystem Function’’ (MarBEF); FP6, EC contract no. 505446 and a grant from the Fundacio ´n BBVA. EPM was supported by a European Union Marie Curie host fellowship for transfer of knowledge, MTKD-CT-2004-509254, the Spanish national project EVAMARIA (CTM2005-00395/MAR) and the regional government of Andalusia project FUNDIV(P07-RNM-2516)

Testing angular velocity as a new metric for metabolic demands of slow-moving marine fauna: a case study with Giant spider conchs Lambis truncata

BackgroundQuantifying metabolic rate in free-living animals is invaluable in understanding the costs of behaviour and movement for individuals and communities. Dynamic body acceleration (DBA) metrics, such as vectoral DBA (VeDBA), are commonly used as proxies for the energy expenditure of movement but are of limited applicability for slow-moving species. It has recently been suggested that metrics based on angular velocity might be better suited to characterise their energetics. We investigated whether a novel metric—the ‘Rate of change of Rotational Movement (RocRM)’, calculated from the vectoral sum of change in the pitch, roll and yaw/heading axes over a given length of time, is a suitable proxy for energy expenditure.ResultsWe found that RocRM can be used as an alternative energy expenditure proxy in a slow-moving benthic invertebrate. Eleven Giant spider conchs Lambis truncata (collected in the Red Sea) were instrumented with multiple channel (Daily Diary) tags and kept in sealed chambers for 5 h while their oxygen consumption, V̇O2, was measured. We found RocRM to be positively correlated with V̇O2, this relationship being affected by the time-step (i.e. the range of the calculated differential) of the RocRM. Time steps of 1, 5, 10 and 60 s yielded an explained variability of between 15 and 31%. The relationship between V̇O2 and VeDBA was not statistically significant, suggesting RocRM to provide more accurate estimations of metabolic rates in L. truncata.ConclusionsRocRM proved to be a statistically significant predictor of V̇O2 where VeDBA did not, validating the approach of using angular-based metrics over dynamic movement-based ones for slower moving animals. Further work is required to validate the use of RocRM for other species, particularly in animals with minimally dynamic movement, to better understand energetic costs of whole ecosystems. Unexplained variability in the models might be a consequence of the methodology used, but also likely a result of conch activity that does not manifest in movement of the shell. Additionally, density plots of mean RocRM at each time-step suggest differences in movement scales, which may collectively be useful as a species fingerprint of movement going forward

Impact of the COVID-19 pandemic on diagnoses of common mental health disorders in adults in Catalonia, Spain : a population-based cohort study

To investigate how trends in incidence of anxiety and depressive disorders have been affected by the COVID-19 pandemic. Population-based cohort study. Retrospective cohort study from 2018 to 2021 using the Information System for Research in Primary Care (SIDIAP) database in Catalonia, Spain. 3 640 204 individuals aged 18 or older in SIDIAP on 1 March 2018 with no history of anxiety and depressive disorders. The incidence of anxiety and depressive disorders during the prelockdown period (March 2018-February 2020), lockdown period (March-June 2020) and postlockdown period (July 2020-March 2021) was calculated. Forecasted rates over the COVID-19 periods were estimated using negative binomial regression models based on prelockdown data. The percentage of reduction was estimated by comparing forecasted versus observed events, overall and by sex, age and socioeconomic status. The incidence rates per 100 000 person-months of anxiety and depressive disorders were 151.1 (95% CI 150.3 to 152.0) and 32.3 (31.9 to 32.6), respectively, during the prelockdown period. We observed an increase of 37.1% (95% prediction interval 25.5 to 50.2) in incident anxiety diagnoses compared with the expected in March 2020, followed by a reduction of 15.8% (7.3 to 23.5) during the postlockdown period. A reduction in incident depressive disorders occurred during the lockdown and postlockdown periods (45.6% (39.2 to 51.0) and 22.0% (12.6 to 30.1), respectively). Reductions were higher among women during the lockdown period, adults aged 18-34 years and individuals living in the most deprived areas. The COVID-19 pandemic in Catalonia was associated with an initial increase in anxiety disorders diagnosed in primary care but a reduction in cases as the pandemic continued. Diagnoses of depressive disorders were lower than expected throughout the pandemic

Tráfico vehicular y peatonal, un indicador de sostenibilidad urbana para la ciudad de Cuenca

Both vehicular and pedestrian traffic is a problem that developing cities are currently experiencing, with the growth of the population and the number of vehicles, the spaces of mobilization are experiencing congestion, affecting the sustainability of the city. To achieve an early analysis of this problem, indicators have been created to describe a phenomenon qualitatively or quantitatively, but their extensive study has generated an extensive list of these, where regions with limited resources and without a culture of data collection, are inapplicable and unreliable. Therefore, the objective of this study is to evaluate a framework of sustainable indicators that describe the phenomenon of vehicular and pedestrian traffic for a specific area, and to obtain a list of applicable and relevant indicators. The methodology begins with the identification of bibliographic sources and the selection of indicators already evaluated to obtain an initial list, as a second step, this list of indicators was zoned based on expert opinion, fulfilling the criteria imposed, and finally it was verified that these indicators are applicable. In this study, a list of verified, measurable and applicable indicators was obtained for any zone of the city of Cuenca and a methodology of analysis that presents a wide potential for the zoning of sustainable indicators, this selection is absolutely based on the opinion of expert judgment.Tanto el tráfico vehicular y peatonal es un problema que actualmente están viviendo las ciudades en desarrollo, con el crecimiento de la población y del parque automotor, los espacios de movilización experimentan una congestión afectando la sustentabilidad de la ciudad. Para lograr un pronto análisis de este problema se han creado indicadores que describen cualitativa o cuantitativamente un fenómeno, pero su amplio estudio ha generado una extensa lista de estos, en donde las regiones con recursos limitados y sin cultura de recolección de información, son inaplicables y poco confiables. Por ende, el objetivo de este estudio se evalúa un marco de indicadores sostenibles que describan el fenómeno de tráfico vehicular y peatonal para una zona específica, y obtener una lista de indicadores aplicables y relevantes. La metodología comienza con la identificación de fuentes bibliográficas y la selección de indicadores ya comprobados para obtener una lista inicial, como segundo paso se zonificó esta lista de indicadores en base de opinión de expertos cumpliendo los criterios impuestos, finalmente se comprobó que estos indicadores son aplicables. En este estudio, se obtuvo una lista de indicadores verificados, medibles y aplicables para cualquier zona de la ciudad de Cuenca y una metodología de análisis que presenta un amplio potencial para la zonificación de indicadores sostenibles, queda claro que esta selección se basa absolutamente en la opinión del juicio de expertos

The natural history of symptomatic COVID-19 during the first wave in Catalonia

The natural history of coronavirus disease 2019 (COVID-19) has yet to be fully described. Here, we use patient-level data from the Information System for Research in Primary Care (SIDIAP) to summarise COVID-19 outcomes in Catalonia, Spain. We included 5,586,521 individuals from the general population. Of these, 102,002 had an outpatient diagnosis of COVID-19, 16,901 were hospitalised with COVID-19, and 5273 died after either being diagnosed or hospitalised with COVID-19 between 1st March and 6th May 2020. Older age, being male, and having comorbidities were all generally associated with worse outcomes. These findings demonstrate the continued need to protect those at high risk of poor outcomes, particularly older people, from COVID-19 and provide appropriate care for those who develop symptomatic disease. While risks of hospitalisation and death were lower for younger populations, there is a need to limit their role in community transmission