5. Impacto del cambio climático en la sedimentación y en la acumulación de carbono en los lagos de la Amazonia peruana

Los suelos, las aguas y los sedimentos de la cuenca amazónica son importantes compartimentos del ciclo de carbono, el cual se encuentra parcialmente almacenado en los bosques inundables y en los lagos de inundación de la región (20% de la superficie total de la cuenca). Estudiar los procesos de sedimentación lacustres a diferentes escalas espaciales y de tiempo permite mejorar le estimación del balance biogeoquímico del carbono (uno de los gases de efecto Invernadero responsable del cambio climático actual, el CO2). Las tasas de sedimentación en las áreas de inundación dependen de varios factores, como el tipo de agua de los lagos y del tipo de conexión que tienen con los ríos. El análisis en laboratorio de muestras de sedimentos, que mantienen la secuencia de deposición, sirve para determinar las condiciones geológicas, meteorológicas, los cambios en el ecosistema e incluso acciones de origen humano que pueden haber afectado los regímenes de sedimentación y la composición de los sedimentos a lo largo del tiempo.Les sols, les eaux et les sédiments du bassin amazonien sont des compartiments importants du cycle du carbone, qui est partiellement stocké dans les forêts et les lacs inondés dans la région (20% de la superficie totale du bassin). Connaître les processus de sédimentation lacustres à différentes échelles spatiales et temporelles permet d'améliorer l'estimation de l'équilibre biogéochimique du carbone (un des gaz responsables du changement climatique actuel, CO2). Les taux de sédimentation dans la plaine inondable dépendent de plusieurs facteurs, y compris le type d'eau des lacs et le type de connexion avec les rivières. Les analyses de laboratoire des échantillons de sédiments, qui maintiennent la séquence de dépôt, sont utilisées pour déterminer les caractéristiques géologiques, les conditions météorologiques, les changements dans l'écosystème et même les actions humaines qui peuvent avoir une incidence sur les régimes de sédimentation et la composition des sédiments au fil du temps.The soils, waters and sediments of the Amazon basin are important compartments of the carbon cycle, which are partially stored in flooded forests and lakes of flooding in the region (20% of the total basin area). The study of lacustrine sedimentation processes at different spatial and temporal scales allows improving the estimation of biogeochemical carbon balance (one of the greenhouse gases responsible for the current climate change, CO2). Sedimentation rates in flood areas depend on several factors, such as the type of water from lakes and the type of connection this water has with rivers. The laboratory analysis of sediment samples, which maintain the deposition sequence, is used to determine geological and meteorological conditions; as well as changes in the ecosystem, even actions arising from humans that may have affected the sedimentation regimes and sediment composition along the time

4. HYBAM: un observatorio para medir el impacto del Cambio Climático sobre la erosión y los flujos de sedimentos en la zona Andino-Amazónica

La cuenca Amazónica es la más grande del mundo. La instalación del observatorio HYBAM con una amplia red de estaciones hidrológicas ubicadas desde el piedemonte andino hasta el océano Atlántico permite, desde el 2003, la generación de registros periódicos y confiables (nivel del agua, caudal, concentración de sedimentos y otros parámetros físico-químicos de la calidad del agua) a lo largo de toda la cuenca. Hoy en día, el desarrollo de técnicas satelitales, como la altimetría, permite completar eficientemente los datos obtenidos por las redes de medición en los ríos. El recrudecimiento de eventos extremos en la Amazonia (Inundaciones, sequias,) por efecto del cambio climático actual asociado a un cambio acelerado de ocupación de los suelos (deforestación, prácticas agrícolas), tiene una incidencia directa sobre la producción sedimentarla. Conocer los flujos de materiales transportados por los ríos es esencial tanto para la navegación fluvial como para guiar la explotación de los recursos naturales (agua, petróleo, minerales), para conocer el transporte de partículas contaminantes o para diseñar infraestructuras.Le bassin de l’Amazone est le plus grand du monde. La mise en œuvre de l’observatoire HYBAM avec un vaste réseau de stations hydrologiques situées sur les contreforts des Andes jusqu’á l’océan Atlantique permet de générer, depuis 2003, des données régulières et fiables tout le long du bassin (hauteur d’eau, débit, concentration de sédiments et d’autres paramètres physico-chimiques de qualité de l’eau). De nos jours, la mise au point des techniques par satellite, tels que l’altimétrie, permet de compléter efficacement les données obtenues par les réseaux de mesure dans les rivières. L’intensification des événements extrêmes dans la région amazonienne (inondations, sécheresses), liés au changement climatique actuel associé á un changement rapide de l’utilisation des terres (déforestation, pratiques agricoles), ont un impact direct sur la production de sédiments. Connaître les flux de matières transportés par les rivières est essentiel pour la navigation fluviale ainsi que pour guider l’exploitation des ressources naturelles (eau, pétrole, minéraux), connaître le trajet de particules polluantes ou concevoir des infrastructures.The Amazon basin is the largest basin in the world. The implementation of the HYBAM observatory, which has installed a large network of hydrological stations located from the Andean foothills down to the Atlantic Ocean, allows since 2003, generate periodical and reliable records (such as water level, flow, sediment concentration and other physicochemical parameters of water quality) along the entire basin. Nowadays, the development of satellite techniques, (such as altimetry), makes it possible to efficiently complete the data obtained by the measurement networks in rivers. The intensification of extreme events in the Amazon region (floods, droughts) occurred as a result of the current Climate Change associated with a more rapid change of land use (deforestation, agricultural practices) have a direct impact on sediment production. It is essential to know the flows of the materials transported by rivers, both for river navigation as well as to guide the exploitation of natural resources (water, oil, minerals), to know the transport of particulate pollutants, or to design infrastructures

Effect of COVID-19 pandemic lockdowns on planned cancer surgery for 15 tumour types in 61 countries: an international, prospective, cohort study

Background Surgery is the main modality of cure for solid cancers and was prioritised to continue during COVID-19 outbreaks. This study aimed to identify immediate areas for system strengthening by comparing the delivery of elective cancer surgery during the COVID-19 pandemic in periods of lockdown versus light restrictions. Methods This international, prospective, cohort study enrolled 20 006 adult (>= 18 years) patients from 466 hospitals in 61 countries with 15 cancer types, who had a decision for curative surgery during the COVID-19 pandemic and were followed up until the point of surgery or cessation of follow-up (Aug 31, 2020). Average national Oxford COVID-19 Stringency Index scores were calculated to define the government response to COVID-19 for each patient for the period they awaited surgery, and classified into light restrictions (index 60). The primary outcome was the non-operation rate (defined as the proportion of patients who did not undergo planned surgery). Cox proportional-hazards regression models were used to explore the associations between lockdowns and non-operation. Intervals from diagnosis to surgery were compared across COVID-19 government response index groups. This study was registered at ClinicalTrials.gov, NCT04384926. Findings Of eligible patients awaiting surgery, 2003 (10middot0%) of 20 006 did not receive surgery after a median follow-up of 23 weeks (IQR 16-30), all of whom had a COVID-19-related reason given for non-operation. Light restrictions were associated with a 0middot6% non-operation rate (26 of 4521), moderate lockdowns with a 5middot5% rate (201 of 3646; adjusted hazard ratio [HR] 0middot81, 95% CI 0middot77-0middot84; p<0middot0001), and full lockdowns with a 15middot0% rate (1775 of 11 827; HR 0middot51, 0middot50-0middot53; p<0middot0001). In sensitivity analyses, including adjustment for SARS-CoV-2 case notification rates, moderate lockdowns (HR 0middot84, 95% CI 0middot80-0middot88; p<0middot001), and full lockdowns (0middot57, 0middot54-0middot60; p<0middot001), remained independently associated with non-operation. Surgery beyond 12 weeks from diagnosis in patients without neoadjuvant therapy increased during lockdowns (374 [9middot1%] of 4521 in light restrictions, 317 [10middot4%] of 3646 in moderate lockdowns, 2001 [23middot8%] of 11 827 in full lockdowns), although there were no differences in resectability rates observed with longer delays. Interpretation Cancer surgery systems worldwide were fragile to lockdowns, with one in seven patients who were in regions with full lockdowns not undergoing planned surgery and experiencing longer preoperative delays. Although short-term oncological outcomes were not compromised in those selected for surgery, delays and non-operations might lead to long-term reductions in survival. During current and future periods of societal restriction, the resilience of elective surgery systems requires strengthening, which might include protected elective surgical pathways and longterm investment in surge capacity for acute care during public health emergencies to protect elective staff and services.Funding National Institute for Health Research Global Health Research Unit, Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, Medtronic, Sarcoma UK, The Urology Foundation, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research. Copyright (c) 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license

Lipolytic enzymes and hydrolytic rancidity

Lipolysis, the enzymic hydrolysis of milk lipids to free fatty acids and partial glycerides, is a constant concern to the dairy industry because of the detrimental effcts it can have on the flvor and other properties of milk and milk products. However, free fatty acids also contribute to the desirable flavor of milk and milk products when present at low concentrations and, in some cheeses, when present at high concentrations. The enzymes responsible for the detrimental effects of lipolysis are of two main types: those indigenous to milk, and those of microbial origin. The major indigenous milk enzyme is lipoprotein lipase. It is active on the fat in natural milk fat globules only after their disruption by physical treatments or if certain blood serum lipoproteins are present. The major microbial lipases are produced by psychrotrophic bacteria. Many of these enzymes are heat stable and are particularly significant in stored products. Human milk differs from cows' milk in that it contains two lipases, a lipoprotein lipase and a bile salt-stimulated lipase. The ability of the latter to cause considerable hydrolysis of ingested milk lipids has important nutritional implications