Modelación de nicho y aspectos biogeográfícos del género Sotalia (Cetartiodactyla: Delphinidae) en los ríos Amazonas y Orinoco, Colombia

El género Sotalia (Cetartiodactyla: Delphinidae) esta compuesto de dos especies, basados en morfología craneal y evidencia genética. La primera Sotalia fluviatilis (continental) corresponde a individuos distribuidos en la cuenca del río Amazonas y Sotalia guianensis (Orinoco y Océano Atlántico) presentes en las costas de Océano Atlántico en Centro y Sur América, incluido el delta del río Orinoco y el Lago Maracaibo en Venezuela. Las individuos establecidos en el medio y bajo Orinoco, corresponden a individuos que presentan 600.000 años de divergencia genética de las poblaciones costeras correspondientes a S. guianensis. El tucuxi, S. fluviatilis es simpatrico con Inia geoffrensis para la cuenca del río Amazonas. Se caracterizaron ecológicamente los avistamientos realizados para el género Sotalia en las cuencas de los ríos Amazonas y Orinoco y el efecto de su interconectividad sobre los patrones biogeográficos a través del modelamiento del nicho ecológico (nicho climático) en aras de establecer la distribución potencial del género Sotalia empleando el algoritmo de Máxima Entropía (MaxEnt) y sistemas de información geográfica junto con variables ecográficas e hidrográficas, asociadas a los sistemas acuáticos habitados por estas especies de cetáceos. Los resultados sugieren que la especies S. fluviatilis y S. guianensis presentan limitaciones a su distribución generado por los raudales como Córdoba en el río Caquetá (Amazonas) y Maipures y Atures en el río Orinoco (Venezuela). Finalmente, se resalta la importancia de este tipo de investigaciones, que emplean aproximaciones ecológicas para inferir las distribuciones potenciales de estas especies en los sistemas acuáticos de la Amazonia y Orinoquia

Caracterización ecológica de cuencas utilizadas por el delfín rosado Inia geoffrensis en Colombia, a través de modelamiento de nicho

Aunque los delfines rosados son mamíferos acuáticos obligados, variables ambientales atmosféricas asociadas a las cuencas de los ríos que habitan, como la precipitación y la temperatura, se constituyen en determinantes de su ecología, afectando directamente su ocurrencia en un área particular. Para Colombia, se reconocen dos subespecies de Inia geoffrensis, distribuidas en las cuencas del Orinoco (Inia geoffrensis humboldtiana) y Amazonas (Inia geoffrensis geoffrensis). Accidentes geomorfológicos como los rápidos, se han sugerido como barreras que separan las poblaciones naturales de delfines, promoviendo potencialmente procesos de especiación que pueden estar siendo reforzados por ecologías contrastantes entre cuencas. A la fecha, no se cuenta con un análisis comprensivo sobre la diferenciación ecológica entre las cuencas habitadas por las subespecies de Inia geoffrensis. En este trabajo, a través de herramientas de modelamiento de nicho, investigamos la potencial diferenciación ecológica entre las dos subespecies de Inia para el territorio colombiano. Los modelos aquí presentados fueron construidos usando el algoritmo MaxEnt a través de la integración de 8435 avistamientos de delfines (I. g. geoffrensis N= 3592 y I. g. humboldtiana N= 4843), y 22 variables ambientales derivadas de la base de datos Bioclim e Hydroshed, que fueron parametrizadas en el programa R. Las áreas con alta disponibilidad para los delfines rosados, realizadas por nuestros modelos, fueron congruentes con la distribución previa propuesta para las dos subespecies en Colombia y estuvieron fuertemente soportadas por la métrica del área bajo la curva (AUC 0,985). Nuestros resultados sugieren una diferenciación ecológica entre las cuencas ocupadas por las subespecies de delfines rosados. En globalidad, concluimos que factores externos al ambiente acuático, tienen participación en la diferenciación ecológica entre las subespecies de I. geoffrensis

Resurgence of vaccine-preventable diseases in Venezuela as a regional public health threat in the Americas

Venezuela’s tumbling economy and authoritarian rule have precipitated an unprecedented humanitarian crisis. Hyperinflation rates now exceed 45,000%, and Venezuela’s health system is in free fall. The country is experiencing a massive exodus of biomedical scientists and qualified healthcare professionals. Reemergence of arthropod-borne and vaccine-preventable diseases has sparked serious epidemics that also affect neighboring countries. In this article, we discuss the ongoing epidemics of measles and diphtheria in Venezuela and their disproportionate impact on indigenous populations. We also discuss the potential for reemergence of poliomyelitis and conclude that action to halt the spread of vaccine-preventable diseases within Venezuela is a matter of urgency for the country and the region. We further provide specific recommendations for addressing this crisis. © 2019 Centers for Disease Control and Prevention (CDC). All rights reserved

SELNET clinical practice guidelines for bone sarcoma

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

An Output Feedback Discrete-Time Controller for the DC-DC Buck Converter

This paper presents a discrete-time output feedback controller to regulate the output voltage of a DC-DC buck converter. The proposal&rsquo;s main feature is the application of a discrete-time equivalent of the robust exact filtering differentiator. First, the document exposes a theoretical analysis of the closed-loop system, where it is considered the problem of implementing a real-time differentiator with a good relationship between exactness and noise filtration performance. Hence, secondly, the controller in a laboratory setup is presented. The first experimental results suggest that the proposed controller exhibits good robustness against noise and maintains the asymptotic accuracy, even with saturated control inputs, as in the case of the DC-DC buck converter. Consequently, aiming to verify the features of the proposed method, the controller is validated through multiple experiments, showing satisfactory voltage tracking accuracy, good suppression of instantaneous load and supply voltage disturbances, and robustness against bounded measurement noise

An Output Feedback Discrete-Time Controller for the DC-DC Buck Converter

This paper presents a discrete-time output feedback controller to regulate the output voltage of a DC-DC buck converter. The proposal’s main feature is the application of a discrete-time equivalent of the robust exact filtering differentiator. First, the document exposes a theoretical analysis of the closed-loop system, where it is considered the problem of implementing a real-time differentiator with a good relationship between exactness and noise filtration performance. Hence, secondly, the controller in a laboratory setup is presented. The first experimental results suggest that the proposed controller exhibits good robustness against noise and maintains the asymptotic accuracy, even with saturated control inputs, as in the case of the DC-DC buck converter. Consequently, aiming to verify the features of the proposed method, the controller is validated through multiple experiments, showing satisfactory voltage tracking accuracy, good suppression of instantaneous load and supply voltage disturbances, and robustness against bounded measurement noise

Pool choice in a vertical landscape : Tadpole‐rearing site flexibility in phytotelm‐breeding frogs

Many species of Neotropical frogs have evolved to deposit their tadpoles in small water bodies inside plant structures called phytotelmata. These pools are small enough to exclude large predators but have limited nutrients and high desiccation risk. Here, we explore phytotelm use by three common Neotropical species: Osteocephalus oophagus, an arboreal frog that periodically feeds eggs to its tadpoles; Dendrobates tinctorius, a tadpole-transporting poison frog with cannibalistic tadpoles; and Allobates femoralis, a terrestrial tadpole-transporting poison frog with omnivorous tadpoles. We found that D. tinctorius occupies pools across the chemical and vertical gradient, whereas A. femoralis and O. oophagus appear to have narrower deposition options that are restricted primarily by pool height, water capacity, alkalinity, and salinity. Dendrobates tinctorius tadpoles are particularly flexible and can survive in a wide range of chemical, physical, and biological conditions, whereas O. oophagus seems to prefer small, clear pools and A. femoralis occupies medium-sized pools with abundant leaf litter and low salinity. Together, these results show the possible niche partitioning of phytotelmata among frogs and provide insight into stressors and resilience of phytotelm breeders.peerReviewe

Pool choice in a vertical landscape: Tadpole-rearing site flexibility in phytotelm-breeding frogs

Many species of Neotropical frogs have evolved to deposit their tadpoles in small water bodies inside plant structures called phytotelmata. These pools are small enough to exclude large predators but have limited nutrients and high desiccation risk. Here, we explore phytotelm use by three common Neotropical species: Osteocephalus oophagus, an arboreal frog that periodically feeds eggs to its tadpoles; Dendrobates tinctorius, a tadpole-transporting poison frog with cannibalistic tadpoles; and Allobates femoralis, a terrestrial tadpole-transporting poison frog with omnivorous tadpoles. We found that D. tinctorius occupies pools across the chemical and vertical gradient, whereas A. femoralis and O. oophagus appear to have narrower deposition options that are restricted primarily by pool height, water capacity, alkalinity, and salinity. Dendrobates tinctorius tadpoles are particularly flexible and can survive in a wide range of chemical, physical, and biological conditions, whereas O. oophagus seems to prefer small, clear pools and A. femoralis occupies medium-sized pools with abundant leaf litter and low salinity. Together, these results show the possible niche partitioning of phytotelmata among frogs and provide insight into stressors and resilience of phytotelm breeders