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Water use efficiency in an arid watershed: a case study

Research in Cold and Arid Regions 2013年第1期5卷 16-26页

作者： Damaris Orphanopoulos Koen Verbist alvaro chavez Guido Soto Rodhos Consulting Vaticano 4026 B Santiago Chile UNESCO-International Hydrological Programme 1 Rue Miolis Paris France Centro del Agua para Zonas áridas y Semiáridas de América Latina y el Caribe (CAZALAC) Benavente 980 La Serena Chile

Integrated Water Resource Management （IWRM） becomes increasingly important in arid watersheds, where water resources are scarce and demands are rising under increased population pressure. In this case study, we present the results from the Elqui Valley in Chile, where water resources are shared between agriculture, mining operations, hydropower generation and drinking water for nearby cities. An IWRM model was applied to visualize water resources distribution in the catchment and determine irrigation and water use efficiencies. After calibration with observed surface and groundwater measurements, the model showed large differ- ences in efficiencies between different irrigation sectors. Most notably, irrigation sectors with the highest irrigation security, i.e., higher water rights per hectare, were characterized with lower water use efficiencies. Frequent water deficits were present in sec- tors downstream of the main reservoir, which was related to limited water rights per hectare, lower irrigation efficiencies and higher water demands due to larger agricultural areas. In subsequent scenario analyses, the model was used to evaluate the impact of improved irrigation and water use efficiencies in these downstream sectors, to confirm an important reduction in water deficits, except for drought years when surface water resources are insufficient. In a third scenario, groundwater resources were allowed to compensate for water deficits, effectively reducing these in most irrigation sectors, especially during droughts. Expansion of the current agricultural area by 37% was evaluated, as a future scenario, and was found to be unsustainable, as aquifer levels are low- ered to such levels that make annual recharge insufficient.

关键词： integrated water resources management drought arid zones Chile

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Pancreatic neuroendocrine tumors:Are tumors smaller than 2 cm truly indolent?

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1756-1762页

作者： Sergio Hoyos Pablo Posada-Moreno Natalia Guzman-Arango Romario Chanci-Drago Jaime chavez alvaro Andrés-Duarte Santiago Salazar-Ochoa Hepatobilary and Liver Transplant Unit Hospital Pablo Tobon Uribe and Gastrohepathology Group Universidad de AntioquiaMedellin 050034AntioquiaColombia Department of General Surgery Universidad Pontificia BolivarianaMedellín 050034AntioquiaColombia

BACKGROUND Pancreatic neuroendocrine tumors(PNETs)are relatively rare but rank as the second most common pancreatic *** can be functional,causing early metabolic disturbances due to hormone secretion,or non-functional and diagnosed later based on tumor size-related *** diagnoses of PNETs under 2 cm in size have sparked debates about their management;some practitioners advocate for surgical removal and others suggest observation due to the tumors’lower potential for ***,it is unclear whether managing these small tumors expectantly is truly *** To evaluate poor prognostic factors in PNETs based on tumor size(>2 cm or<2 cm)in surgically treated *** This cohort study included 64 patients with PNETs who underwent surgical resection between 2006 and 2019 at a high-complexity reference hospital in Medellín,*** assess patient survival,quarterly follow-ups were conducted during the first year after surgery,followed by semi-annual con-sultations at the hospital's hepatobiliary surgery *** variables were described using absolute and relative frequencies,and quantitative variables were expressed using measures of central tendency and their corresponding measures of *** The presence of lymph node involvement,neural involvement,and lymphovascular invasion were all associated with an increased risk of mortality,with hazard ratios of 5.68(95%CI:1.26–25.61,P=0.024),6.44(95%CI:1.43–28.93,P=0.015),and 24.87(95%CI:2.98–207.19,P=0.003),*** involvement and lymphovascular invasion were present in tumors smaller than 2 cm in diameter and those larger than 2 cm in *** recurrence rates between the two tumor groups were furthermore similar:18.2%for tumors smaller than 2 cm and 21.4%for tumors larger than 2 *** survival was additionally comparable between the two tumor *** Tumor size does not dictate prognosis;lymph node and lymphovascular involvement a

关键词： Neuroendocrine tumor Pancreatic neoplasm Pancreas Pancreatic neuroendocrine neoplasm Pancreatic neuroendocrine tumors

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