Comportamiento del nitrógeno y fósforo en el estuario y en la pluma del río Ebro

La desembocadura del río Ebro es un estuario estratificado que cuando desemboca en el mar Mediterráneo forma una pluma cuya distribución está controlada fundamentalmente por la descarga del río y los vientos locales. Para estudiar el comportamiento de los nutrientes en el proceso de mezcla estuarina se recurrió a los gráficos de "curvas de mezcla" que aportan gran información si bien requiere una apropiada elección de los extremos (dulce y salino). Al estudiar el comportamiento del nitrógeno y fósforo se observó que amonio y PSR se comportan de diferente manera en el estuario que en la pluma, mientras que el nitrato y el nitrito tienen pautas de comportamiento similares en ambos ambientes. En el estuario se observan claras ganancias para el amonio y el fósforo que son consecuencia de la remineralización de la materia orgánica que se acumula principalmente en la zona de la interfase de la cuña salina. En cambio, en la pluma el comportamiento del amonio y del fósforo muestran pérdidas debidas probablemente a la absorción por parte del fitoplancton. Nitrito y nitrato exhiben comportamientos prácticamente conservativos tanto en el estuario como en la pluma.Romero Gil, I.; Falco Giaccaglia, SL.; González Del Rio Rams, J.; Rodilla Alamá, M.; Sierra, J.; Pérez Baliero, MDC.; Mosso, C. (2007). Comportamiento del nitrógeno y fósforo en el estuario y en la pluma del río Ebro. INGENIERIA DEL AGUA. 14(1):47-56. https://doi.org/10.4995/ia.2007.2902S4756141Agius, C. y V. Jaccarini, (1982). The effect of nitrate and phosphate enrichments on the phytoplankton from Marsaxlokk Bay, Malta (Central Mediterranean). Hydrobiologia, 87, 89-96.Aminot, A., (1983). Mesure de la salinité. En: Manuel des analyses chimiques en milieu marin, Aminot, A. y M. Chaus-sepied, (Eds.), M. Centre National pour l'Explotation des Océans, Brest, 45-62.APHA, (1995). Standard methods for the examination of water and wastewater, 19th edition. American Public Health Association, American Water Works Association, Water Environment Federation, Washington, 1108 pp.Broche, P., J.L. Devenon, P. Forget, J.C. de Maistre, J.J. Naudin y G. Cauwet, (1998). Experimental study of the Rhone plume. Part I: Physics and dynamics. Oceanologica Acta, 21 (6), 725-738.Burton, J.D., (1976). Basic properties and processes in estuarine chemistry. En: Burton, J. D. y P. S. Liss (eds), Estuarine chemistry. Academis Press, 1-36.Davies, A.M. y J.X. Xing, (1999). Sensitivity of plume dynamics to the parameterization of vertical mixing. International journal for numerical methods in fluids, 30, 357-405.Dolz Ripollés, J., M. Gómez Valentín y J. Nieto Romeral, (1997). El Ebro en el delta. Revista de Obras Públicas, No. 3.368, 7-14.Estrada, M., (1996). Primary production in the northwestern Mediterranean. Scient. Mar., 60 (Suppl 2), 50-64.Geyer, W.R. y D.M. Farmer, (1989). Tide-induced variation of the dynamics of a salt wedge estuary. Journal of Physical Oceanography, 19, 1060-1072.Ibáñez, C., D. Pont y N. Prat, (1997). Characterization of the Ebre and Rhone estuaries - A basis for defining and classifying saltwedge estuaries. Limnol. Oceanogr., 42 (1), 89-101.Kirkwood, D., A. Aminot y M. Pertillä, (1991). Report on the results of the fourth intercomparison exercise for nutrients in seawater. ICES Cooperative Research Report, 174, 83 pp.Kress N. y B. Herut, (1998). Hypernutrification in the oligotrophic eastern Mediterranean: A study in Haifa Bay (Israel). Estuar. coast. Shelf Sci., 46 (5), 645-656.Krom, M.D., N. Kress, S. Brenner y L.I. Gorden, (1991). Phosphorus limitation of primary productivity in the eastern Mediterranean sea. Limnol. Oceanogr., 36 (3), 424-432.Lohrenz, S.E., G.L. Fahnenstiel, D.G. Redalje, G.A. Lang, M. J. Dagg, T.E. Whitledge y Q. Dortch, (1999). Nutrients, irradiance, and mixing as factors regulating primary production in coastal waters impacted by the Mississippi River plume. Cont. Shelf Res., 19 (9), 1113-1141.Loder, T.C. y R.P. Reichard, (1981). The dynamics of conservative mixing in estuaries. Estuaries, 4 (1), 64-69.Lopez-Veneroni, D. y L.A. Cifuentes, (1994). Transport of dissolved organic nitrogen in Mississippi River plume and Texas-Louisiana continental shelf near-surface waters. Estuaries, 17 (4), 796-808.Magnien, R.E., R.M. Summers, y K.G. Sellner, (1992). External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay. Estuaries, 15 (4), 497{516.Marsaleix, P., C. Estournel, V. Kondrachoff y R. Vehil, (1998). A numerical study of the formation of the Rhone River plume. J. Mar. Syst., 14 (1-2), 99-115.Morris, A.W., J.I. Allen, R.J.M. Howland, y R.G. Wood, (1995). The estuary plume zone: Source or sink for land derived nutrient discharges?. Estuar. coast. 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Deslous-Paoli, (1997). Biogeochemical composition of Mediterranean waters outside Thau Lagoon. Estuar. coast. Shelf Sci., 44 (3), 275-284.Thingstad, T.F., U. Li-Zweifel y F. Rassoulzadegan, (1998). P limitation of heterotrophic bacteria and phytoplankton in the northwest Mediterranean. Limnol. Oceanogr., 43 (1), 88-94.Treguer, P. y P. Le Corre, (1975). Manuel d'analyse des sels nutritifs dans l'eau de mer. Université de Bretagne Occidentale, Brest, 110 pp.Vollenweider, R.A., A. Rinaldi, R. Viviani y E. Todini, (1996). Assessment of the state of eutrophication in the Mediterranean sea. MAP Technical Reports Series no. 106. UNEP., Athens, 456 p

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Goodbye Hartmann trial: a prospective, international, multicenter, observational study on the current use of a surgical procedure developed a century ago

Background: Literature suggests colonic resection and primary anastomosis (RPA) instead of Hartmann's procedure (HP) for the treatment of left-sided colonic emergencies. We aim to evaluate the surgical options globally used to treat patients with acute left-sided colonic emergencies and the factors that leading to the choice of treatment, comparing HP and RPA. Methods: This is a prospective, international, multicenter, observational study registered on ClinicalTrials.gov. A total 1215 patients with left-sided colonic emergencies who required surgery were included from 204 centers during the period of March 1, 2020, to May 31, 2020. with a 1-year follow-up. Results: 564 patients (43.1%) were females. The mean age was 65.9 ± 15.6 years. HP was performed in 697 (57.3%) patients and RPA in 384 (31.6%) cases. Complicated acute diverticulitis was the most common cause of left-sided colonic emergencies (40.2%), followed by colorectal malignancy (36.6%). Severe complications (Clavien-Dindo ≥ 3b) were higher in the HP group (P < 0.001). 30-day mortality was higher in HP patients (13.7%), especially in case of bowel perforation and diffused peritonitis. 1-year follow-up showed no differences on ostomy reversal rate between HP and RPA. (P = 0.127). A backward likelihood logistic regression model showed that RPA was preferred in younger patients, having low ASA score (≤ 3), in case of large bowel obstruction, absence of colonic ischemia, longer time from admission to surgery, operating early at the day working hours, by a surgeon who performed more than 50 colorectal resections. Conclusions: After 100 years since the first Hartmann's procedure, HP remains the most common treatment for left-sided colorectal emergencies. Treatment's choice depends on patient characteristics, the time of surgery and the experience of the surgeon. RPA should be considered as the gold standard for surgery, with HP being an exception

"Alternative reading on information and communication."

p.55-70

"La comunicación como vacío académico."

El autor señala que el problema fundamental que aqueja el discurso académico de las ciencias de la comunicación, cuando menos en la experiencia mexicana, no radica tanto en las condiciones inmediatas del carácter estructural para la enseñanza y la práctica profesional del periodismo y de las diferentes técnicas de la información, sino en la falta de una reflexión lógico-conceptual más amplia y sistemática respecto de las diferencias formales y pedagógicas que se refieren a la investigación de los problemas comunicativos. En nuestras latitudes, el estudio de la comunicación ha tendido a permanecer en un vacío académico.p.15-24

"¿Hacia una epistemología de la comunicación?"

En este artículo se discuten algunas condiciones epistemológicas de la constituticón científica de la comunicación y se concluye que si la pregunta por la objetividad de la comunicación quiere resolverse y establecerse en una concreción particular para evitar repetir las verdades teóricas establecidas en otros campos del conocimiento social, sólo se va a lograr en la medida en que se emprenda una ruptura epistemológica; ruptura que signifique, ante todo, abrir el cerco tendido por la fetichización ahistórica de los medios masivos y que se cambie el eje del fundamento y la problemática misma de la comunicación a quien realmente la produce y le da sentido y forma: el ser social.p.83-96

BMP2/BMP4 colorectal cancer susceptibility loci in northern and southern European populations.

Genome-wide association studies have successfully identified 20 colorectal cancer susceptibility loci. Amongst these, four of the signals are defined by tagging single nucleotide polymorphisms (SNPs) on regions 14q22.2 (rs4444235 and rs1957636) and 20p12.3 (rs961253 and rs4813802). These markers are located close to two of the genes involved in bone morphogenetic protein (BMP) signaling (BMP4 and BMP2, respectively). By investigating these four SNPs in an initial cohort of Spanish origin, we found substantial evidence that minor allele frequencies (MAFs) may be different in northern and southern European populations. Therefore, we genotyped three additional southern European cohorts comprising a total of 2028 cases and 4273 controls. The meta-analysis results show that only one of the association signals (rs961253) is effectively replicated in the southern European populations, despite adequate power to detect all four. The other three SNPs (rs4444235, rs1957636 and rs4813802) presented discordant results in MAFs and linkage disequilibrium patterns between northern and southern European cohorts. We hypothesize that this lack of replication could be the result of differential tagging of the functional variant in both sets of populations. Were this true, it would have complex consequences in both our ability to understand the nature of the real causative variants, as well as for further study designs