Modelado de flujos de lodo usando FLO-2D en la quebrada Paihua: Impacto en la ciudad de Matucana, Lima

Se propone un modelo bidimensional de diferencias finitas FLO -2D para simular flujo de fluidos no-newtonianos, como aludes torrenciales en conos de deyección, que permita la estimación de la descarga de los huaycos en la Cuenca de la Quebrada Paihua, asumiendo valores de precipitación de 24 horas, para un período de retorno de 100 años como evento detonador. Las características del modelo permiten simular flujos en topografías complejas, como áreas urbanizadas, terrazas, intercambio de fluido entre canales y el cono de deyección. Considera flujos de agua y flujos hiperconcetrados (detritos, lodo, etc.), homogéneo y de concentración variable. Los datos de entrada requieren topografía digital del terreno, la geometría del canal, valores de la rugosidad del canal y de la planicie de inundación, hidrogramas de entrada de líquidos y sólidos, precipitación y propiedades reológicas de la mezcla agua-sedimento. Se establece la caracterización de la Quebrada a nivel topográfico, hidrológico, geológico y de geodinámica. Asimismo se definen los parámetros, como la concentración volumétrica de sedimentos (C), la gravedad específica del sedimento (G¿), resistencia al flujo laminar (K), entre otros. La metodología analiza dos escenarios; 1) el huayco de la quebrada con un flujo presente en el Río Rímac (27.2 m¿/s, caudal estimado del último huayco); 2) un análisis simulando el huayco en la quebrada y con una avenida de 80 m¿/s en el Río Rímac, a fin de poder presentar el fenómeno de desborde e inundación por colmatación. Se toma en cuenta el encauzamiento actual del río. El modelo permite elaborar un mapa de amenaza por niveles

Evolution of landslide activity, and the origin of debris flows in the El Niño affected Payhua Creek basin, Matucana area, Huarochiri, Peru

Matucana, Perú (population 5800; elevation 2390 m), is located in Andes Occidental, approximately 75 km east of Lima. Matucana shares the Río Rimac (RR) flood plain with a strategic highway and railway. Debris flow-prone Quebrada Payhua (Payhua Creek (QP) joins RR at the upstream end of Matucana. Debris flows from QP dammed the RR and diverted it through Matucana in 1959 and 1983. These large debris flows originated in different parts of the QP basin. The steep ravine systems that produced them are supply-limited with respect to debris flow generation. Based on the volumes of debris flows that were produced by ravine systems in 1983, and channel surveys, a maximum volume of ~250 000 m3 is estimated for the total discharge of a basin-wide debris flow event. Large debris flow events that are conditioned by regional rains are the greatest threat during an El Niño year and in the following year. The area of active landslides near Payhua village, has increased by a factor of five since 1951. Although landslide movement in the recent past has been slow and channel blockage by landslides has not been linked to large destructive debris flows, past events cannot be regarded as confident predictors of future events in this case

Numerical Simulation of Debris Flows of the Catastrophic Event of February 2019 in Mirave – Peru

Debris flows are geophysical phenomena, caused by torrential rain, which occur in mountainous areas, characterized by the detachment of slope and riverbed materials and their consequent dislodge through watersheds and streams. Debris flows usually carry sludge, water and rocks, and can destroy everything in their path. On February 8th, 2019, an event of this type occurred and destroyed Mirave’s community in Peru, which was located in the areas of transport and deposition of debris flows. This research presents the modeling and numerical simulation to reproduce the transport and deposition processes of the debris flow that occurred in Mirave. The initiation process of the debris flow in streams was represented by hydrographs obtained from the estimated rain runoff volumes and solid materials found at each evaluated micro watershed. The numerical simulation results show acceptable results in terms of reproduction of the extension of the affectation and deposition areas of solids related to the studied debris flow. The resulting velocity field shows an adequate representation of the erosion zones observed in the area. The model used for evaluating the disaster risk by debris flows can predict and delimit, with acceptable accuracy, the potentially dangerous areas for a mudslide event. The application of the proposed methodology for assessing the disaster risk due to debris flows at watersheds and streams is useful to understand the extent of debris flow affectation during extreme weather events, as well as to develop emergency plans, and to formulate disaster management policies in Peru or in other countries with similar conditions.Os fluxos de detritos são fenômenos geofísicos provocados por chuvas torrenciais, que ocorrem em áreas montanhosas, e se caracterizam pelo desprendimento de materiais de declives e de leitos de rios e seu consequente arraste água abaixo através de bacias e córregos. Os fluxos de detritos carregam consigo, em geral, lodo, água e rochas, e podem destruir tudo o que está em seu caminho. No dia 8 de fevereiro de 2019 ocorreu um evento deste tipo que destruiu a comunidade de Mirave, no Peru, que estava localizada nas áreas de trânsito e deposição dos fluxos de detritos. Esta pesquisa apresenta a modelagem e simulação numérica para reproduzir os processos de iniciação e deposição de fluxos de detritos ocorrido em Mirave. O processo de iniciação dos fluxos de detritos nos desfiladeiros foi representado por hidrogramas obtidos a partir dos volumes estimados de escoamento de água da chuva e materiais sólidos encontrados em cada microbacia avaliada. Os resultados das simulações numéricas mostram resultados aceitáveis em termos de reprodução da extensão do impacto nas áreas de deposição de sólidos relacionados ao fluxo de detritos estudado. O campo de velocidades resultantes mostra uma adequada representação das zonas de erosão observadas in loco. O modelo usado para a avaliação do risco de desastres por fluxos de detritos é capaz de prever e delimitar, com uma aproximação aceitável, as áreas potencialmente perigosas para um evento de deslizamento de terra com um período de retorno determinado. A aplicação da metodologia proposta para avaliação do risco de desastres devido aos fluxos de detritos, a bacias e riachos, é útil para entender a extensão dos impactos gerados pelos fluxos de detritos durante eventos climáticos extremos, bem como para o desenvolvimento de planos de emergência e formulação de políticas de gestão de desastres no Peru

Peligros geológicos por movimientos en masa en la quebrada Paihua-Matucana, Perú

En la quebrada Paihua, se han reconocido importantes peligros geológicos por movimientos en masa: deslizamientos, caídas de rocas, flujos de detritos (huaycos) y erosión de laderas. Estos, por una parte, afectan terrenos de cultivo y por otra aportan gran cantidad de material detrítico a la quebrada, condicionando, de esta manera, la ocurrencia de huaycos o flujos de detritos de gran magnitud, que podrían incidir sobre un sector de la ciudad de Matucana, así como represar total o parcialmente el río Rímac y aumentar el daño por inundaciones sobre la ciudad y centros poblados situados aguas arriba y aguas abajo de la localidad, como ocurrió en el pasado. Dada la ocurrencia de estos procesos, el Instituto Geológico Minero y Metalúrgico (INGEMMET), dentro del marco del Proyecto Multinacional Andino: Geociencias para las Comunidades Andinas (PMA: GCA), cuyo objetivo es contribuir a mejorar la calidad de vida de las poblaciones andinas, creyó conveniente efectuar el Proyecto Piloto: Peligros Geológicos de la quebrada Paihua. Este estudio permite identificar y evaluar las principales causas de los peligros geológicos que afectan las laderas de la quebrada, con la finalidad de buscar alternativas de manejo y plantear las medidas correctivas necesarias. El conocimiento técnico generado por el proyecto se analizó con la población local, mediante su participación en talleres, charlas y concursos, proceso que se prolongará hasta después de la conclusión del estudio. Matucana, con una población de 5.300 habitantes, está localizada en la margen izquierda del río Rímac, en los Andes occidentales, a 72 km al este de la ciudad de Lima, a una altitud de 2.390 m s.n.m. La Carretera y el Ferrocarril Central son las vías que la unen con la capital, con importantes ciudades y unidades mineras del centro del país. La quebrada Paihua, tributaria por la margen derecha al río Rímac, tiene una longitud aproximada de 61 km, ancho promedio de 3 km y altitudes de 4.760 m s.n.m. en sus nacientes

Global disparities in surgeons’ workloads, academic engagement and rest periods: the on-calL shIft fOr geNEral SurgeonS (LIONESS) study

: The workload of general surgeons is multifaceted, encompassing not only surgical procedures but also a myriad of other responsibilities. From April to May 2023, we conducted a CHERRIES-compliant internet-based survey analyzing clinical practice, academic engagement, and post-on-call rest. The questionnaire featured six sections with 35 questions. Statistical analysis used Chi-square tests, ANOVA, and logistic regression (SPSS® v. 28). The survey received a total of 1.046 responses (65.4%). Over 78.0% of responders came from Europe, 65.1% came from a general surgery unit; 92.8% of European and 87.5% of North American respondents were involved in research, compared to 71.7% in Africa. Europe led in publishing research studies (6.6 ± 8.6 yearly). Teaching involvement was high in North America (100%) and Africa (91.7%). Surgeons reported an average of 6.7 ± 4.9 on-call shifts per month, with European and North American surgeons experiencing 6.5 ± 4.9 and 7.8 ± 4.1 on-calls monthly, respectively. African surgeons had the highest on-call frequency (8.7 ± 6.1). Post-on-call, only 35.1% of respondents received a day off. Europeans were most likely (40%) to have a day off, while African surgeons were least likely (6.7%). On the adjusted multivariable analysis HDI (Human Development Index) (aOR 1.993) hospital capacity > 400 beds (aOR 2.423), working in a specialty surgery unit (aOR 2.087), and making the on-call in-house (aOR 5.446), significantly predicted the likelihood of having a day off after an on-call shift. Our study revealed critical insights into the disparities in workload, access to research, and professional opportunities for surgeons across different continents, underscored by the HDI

Pseudorapidity and transverse-momentum distributions of charged particles in proton-proton collisions at root s=13 TeV

The pseudorapidity (eta) and transverse-momentum (p(T)) distributions of charged particles produced in proton-proton collisions are measured at the centre-of-mass energy root s = 13 TeV. The pseudorapidity distribution in vertical bar eta vertical bar <1.8 is reported for inelastic events and for events with at least one charged particle in vertical bar eta vertical bar <1. The pseudorapidity density of charged particles produced in the pseudorapidity region vertical bar eta vertical bar <0.5 is 5.31 +/- 0.18 and 6.46 +/- 0.19 for the two event classes, respectively. The transverse-momentum distribution of charged particles is measured in the range 0.15 <p(T) <20 GeV/c and vertical bar eta vertical bar <0.8 for events with at least one charged particle in vertical bar eta vertical bar <1. The evolution of the transverse momentum spectra of charged particles is also investigated as a function of event multiplicity. The results are compared with calculations from PYTHIA and EPOS Monte Carlo generators. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Modelamiento numérico bidimensional del flujo hiperconcentrado

El Perú no es ajeno a los flujos de huaycos y anualmente ocurren estos eventos en distintas regiones del país produciendo daños materiales y pérdidas humanas. En ese contexto, el estudio y modelamiento de flujos hiperconcentrados (flujos con concentración volumétrica de sedimentos mayor a 20%) permite efectuar un análisis más consistente y confiable en la estimación de parámetros de diseño para medidas de protección. La presente investigación, elabora un programa MUDCP2D n entorno Matlab del modelamiento numérico bidimensional del flujo hiperconcentrado con características de un flujo viscoso transitado sobre un canal a distintas pendientes que se deposita sobre una plataforma. La metodología aplicada comprende la revisión del modelo conceptual de aguas pocas profundas de Saint-Venant en su forma conservativa, la discusión de las ecuaciones gobernantes de los flujos hiperconcentrados, la revisión de la técnica de integración numérica para la resolución de las ecuaciones gobernantes, la aplicación de esquema de MacCormack, el planteamiento y definición del dominio computacional así como el tratamiento de las condiciones de contorno iniciales y las condiciones de borde sobre el dominio computacional. Finalmente, se obtiene el programa MUDCP2D para la validación con la base de datos experimentales Quisca (1995). Un paso siguiente fue el análisis de distintos escenarios para diferentes pendientes y viscosidades del flujo hiperconcentrado con la finalidad de evaluar la sensibilidad del programa MUDCP2D. Se simulan 13 escenarios, de los cuales 4 corresponden a flujo de agua y 9 a flujo hiperconcentrado. La altura inicial del flujo para todos los escenarios propuestos es de 4 m en una longitud de muestra de 50 m y una longitud de tránsito de canal de 200 m. La plataforma al final de tramo es cuadrada de 30 m de longitud y pendiente cero. Los resultados del proceso son tirantes y velocidades máximas en tramo de canal y deposición en plataforma.Peru is not oblivious to the debris flows and these events occur annually in different regions of the country, causing material damage and human losses. In this context, the study and modeling of hyperconcentrated flows (flows with volumetric concentration of sediments greater than 20%) allows a more consistent and reliable analysis to be made in the estimation of design parameters for protection measures. The present investigation elaborates a MUDCP2D software in Matlab language of twodimensional numerical modeling of the hyper-concentrated flow with characteristics of a viscous flow transited on a channel to different slopes that is deposited on a platform. The applied methodology includes the revision of the conceptual model of shallow waters of Saint-Venant in its conservative form, the discussion of the governing equations of the hyper-concentrated flows, the revision of the technique of numerical integration for the resolution of the governing equations, the MacCormack schema application, the approach and definition of the computational domain as well as the treatment of initial boundary conditions and edge conditions over the computational domain. Finally, the MUDCP2D software is obtained for the validation with the experimental database of Quisca (1995). A next step was the analysis of different scenarios for different slopes and dynamic viscosities of the hyper-concentrated flow in order to evaluate the sensitivity of the MUDCP2D software. Thirteen scenarios are simulated, of which four correspond to water flow and nine to hyper-concentrated flow. The initial height of the flow for all proposed scenarios is 4 m for a sample length of 50 m and a channel transit length of 200 m. The platform at the end of the section is square with a length of 30 m and a zero slope. The results of the process are heights and velocities maximum in channel section and platform deposition.TesisUniversidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Recursos Hídrico