Golpe de ariete: simulación del transitorio amortiguado

El Golpe de Ariete es un fenómeno conocido en todo sistema fluidodinámico por las oscilaciones, más o menos importantes, de la presión del fluido y de su velocidad como consecuencia de un cambio en las condiciones de flujo provocado por una perturbación (accidental o programada) aplicada al sistema. Estas oscilaciones producen deterioro en conducciones y accesorios de la instalación, dislocaciones y ruptura de conductos. Las variaciones de presión pueden ser tan amplias que invalidan las suposiciones de homogeneidad y continuidad del fluido.La producción en investigación, en las últimas cuatro décadas, indica que los esfuerzos por mejorar la predicción del comportamiento de la presión transiente han sido puestos en la descripción de la atenuación del fenómeno. La bibliografía muestra que las simulaciones realizadas presentan discrepancias acumulativas tanto en amplitud como en fase.En este trabajo se ha realizado el análisis del fenómeno en un sistema simple reservorio-conducción horizontal?válvula. Se ha modificado el modelo de Golpe de Ariete, introduciendo en el sistema de ecuaciones diferenciales hiperbólicas que lo representan, un término que incluye todos los efectos disipativos de interacción con las paredes de la conducción.Se introdujo en el algoritmo la ley de cierre de válvula como condición de contorno dinámica (extremo donde se emplaza la válvula) y una condición de contorno estática, en el extremo opuesto (embocadura de conexión al tanque). La ley de cierre se ha modelado mediante una función potencial que relaciona el tiempo de cierre con la velocidad del fluido y permite simular el decrecimiento de la velocidad de flujo durante el cierre de válvula para una amplia gama de casos. Las curvas resultantes se discretizaron obteniéndose así poligonales que se utilizaron como condición de contorno para obtener las soluciones correspondientes a cada caso.Se ha resuelto el modelo mediante el Método de las Características, lo que ha permitido predecir presiones y velocidades instantáneas del transitorio. También se ha obtenido la solución analítica del mismo modelo aplicando la Transformada de Laplace Mellín y los postulados del Teorema de Cauchy. Los resultados de la simulación se han contrastado utilizando registros experimentales de laboratorio, observándose una buena concordancia tanto en fase como en amplitud entre las ondas de presión experimentales y predichas.Fil: Provenzano, Pablo Gabriel. Universidad Nacional de Luján. Departamento de Tecnología; ArgentinaFil: Baroni, Francisco J.. Universidad Nacional de Luján. Departamento de Tecnología; ArgentinaFil: Aguerre, Roberto Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Luján. Departamento de Tecnología; Argentina. Universidad de Morón; Argentin

Golpe de ariete: simulación del transitorio amortiguado

El Golpe de Ariete es un fenómeno conocido en todo sistema fluidodinámico por las oscilaciones, más o menos importantes, de la presión del fluido y de su velocidad como consecuencia de un cambio en las condiciones de flujo provocado por una perturbación (accidental o programada) aplicada al sistema. Estas oscilaciones producen deterioro en conducciones y accesorios de la instalación, dislocaciones y ruptura de conductos. Las variaciones de presión pueden ser tan amplias que invalidan las suposiciones de homogeneidad y continuidad del fluido.La producción en investigación, en las últimas cuatro décadas, indica que los esfuerzos por mejorar la predicción del comportamiento de la presión transiente han sido puestos en la descripción de la atenuación del fenómeno. La bibliografía muestra que las simulaciones realizadas presentan discrepancias acumulativas tanto en amplitud como en fase.En este trabajo se ha realizado el análisis del fenómeno en un sistema simple reservorio-conducción horizontal?válvula. Se ha modificado el modelo de Golpe de Ariete, introduciendo en el sistema de ecuaciones diferenciales hiperbólicas que lo representan, un término que incluye todos los efectos disipativos de interacción con las paredes de la conducción.Se introdujo en el algoritmo la ley de cierre de válvula como condición de contorno dinámica (extremo donde se emplaza la válvula) y una condición de contorno estática, en el extremo opuesto (embocadura de conexión al tanque). La ley de cierre se ha modelado mediante una función potencial que relaciona el tiempo de cierre con la velocidad del fluido y permite simular el decrecimiento de la velocidad de flujo durante el cierre de válvula para una amplia gama de casos. Las curvas resultantes se discretizaron obteniéndose así poligonales que se utilizaron como condición de contorno para obtener las soluciones correspondientes a cada caso.Se ha resuelto el modelo mediante el Método de las Características, lo que ha permitido predecir presiones y velocidades instantáneas del transitorio. También se ha obtenido la solución analítica del mismo modelo aplicando la Transformada de Laplace Mellín y los postulados del Teorema de Cauchy. Los resultados de la simulación se han contrastado utilizando registros experimentales de laboratorio, observándose una buena concordancia tanto en fase como en amplitud entre las ondas de presión experimentales y predichas.Fil: Provenzano, Pablo Gabriel. Universidad Nacional de Luján. Departamento de Tecnología; ArgentinaFil: Baroni, Francisco J.. Universidad Nacional de Luján. Departamento de Tecnología; ArgentinaFil: Aguerre, Roberto Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Luján. Departamento de Tecnología; Argentina. Universidad de Morón; Argentin

Peginesatide in patients with anemia undergoing hemodialysis

BACKGROUND: Peginesatide, a synthetic peptide-based erythropoiesis- stimulating agent (ESA), is a potential therapy for anemia in patients with advanced chronic kidney disease. METHODS: We conducted two randomized, controlled, open-label studies (EMERALD 1 and EMERALD 2) involving patients undergoing hemodialysis. Cardiovascular safety was evaluated by analysis of an adjudicated composite safety end point - death from any cause, stroke, myocardial infarction, or serious adverse events of congestive heart failure, unstable angina, or arrhythmia - with the use of pooled data from the two EMERALD studies and two studies involving patients not undergoing dialysis. In the EMERALD studies, 1608 patients received peginesatide once monthly or continued to receive epoetin one to three times a week, with the doses adjusted as necessary to maintain a hemoglobin level between 10.0 and 12.0 g per deciliter for 52 weeks or more. The primary efficacy end point was the mean change from the baseline hemoglobin level to the mean level during the evaluation period; noninferiority was established if the lower limit of the two-sided 95% confidence interval was -1.0 g per deciliter or higher in the comparison of peginesatide with epoetin. The aim of evaluating the composite safety end point in the pooled cohort was to exclude a hazard ratio with peginesatide relative to the comparator ESA of more than 1.3. RESULTS: In an analysis involving 693 patients from EMERALD 1 and 725 from EMERALD 2, peginesatide was noninferior to epoetin in maintaining hemoglobin levels (mean between-group difference, -0.15 g per deciliter; 95% confidence interval [CI], -0.30 to -0.01 in EMERALD 1; and 0.10 g per deciliter; 95% CI, -0.05 to 0.26 in EMERALD 2). The hazard ratio for the composite safety end point was 1.06 (95% CI, 0.89 to 1.26) with peginesatide relative to the comparator ESA in the four pooled studies (2591 patients) and 0.95 (95% CI, 0.77 to 1.17) in the EMERALD studies. The proportions of patients with adverse and serious adverse events were similar in the treatment groups in the EMERALD studies. The cardiovascular safety of peginesatide was similar to that of the comparator ESA in the pooled cohort. CONCLUSIONS: Peginesatide, administered monthly, was as effective as epoetin, administered one to three times per week, in maintaining hemoglobin levels in patients undergoing hemodialysisSupported by Affymax and Takeda Pharmaceutica

Maintenance treatment of renal anaemia in haemodialysis patients with methoxy polyethylene glycol-epoetin beta versus darbepoetin alfa administered monthly: a randomized comparative trial

Background. Several studies with erythropoiesis-stimulating agents claim that maintenance therapy of renal anaemia may be possible at extended dosing intervals; however, few studies were randomized, results varied, and comparisons between agents were absent. We report results of a multi-national, randomized, prospective trial comparing haemoglobin maintenance with methoxy polyethylene glycol-epoetin beta and darbepoetin alfa administered once monthly

Peces de la cuenca del río Orinoco. Parte I: Lista de especies y distribución por subcuencas

Para efectos del presente trabajo y en función de los datos disponibles hasta la fecha, se consideran las siguientes subcuencas y/o regiones para la cuenca del Orinoco, desde su nacimiento hasta su desembocadura en el océano Atlántico: Alto Orinoco, Casiquiare, Ventuari, Atabapo, Inírida, Guaviare, Vichada, Sipapo, Tomo, Cataniapo, Bita, Meta, Parguaza, Cinaruco, Suapure, Capanaparo, Arauca, Apure, Cuchivero, Manapiare, Zuata, Caura, Pao, Aro, Caris, Caroní, Morichal Largo, Delta y Orinoco (Mapa)

Phylogenetic ctDNA analysis depicts early-stage lung cancer evolution.

The early detection of relapse following primary surgery for non-small-cell lung cancer and the characterization of emerging subclones, which seed metastatic sites, might offer new therapeutic approaches for limiting tumour recurrence. The ability to track the evolutionary dynamics of early-stage lung cancer non-invasively in circulating tumour DNA (ctDNA) has not yet been demonstrated. Here we use a tumour-specific phylogenetic approach to profile the ctDNA of the first 100 TRACERx (Tracking Non-Small-Cell Lung Cancer Evolution Through Therapy (Rx)) study participants, including one patient who was also recruited to the PEACE (Posthumous Evaluation of Advanced Cancer Environment) post-mortem study. We identify independent predictors of ctDNA release and analyse the tumour-volume detection limit. Through blinded profiling of postoperative plasma, we observe evidence of adjuvant chemotherapy resistance and identify patients who are very likely to experience recurrence of their lung cancer. Finally, we show that phylogenetic ctDNA profiling tracks the subclonal nature of lung cancer relapse and metastasis, providing a new approach for ctDNA-driven therapeutic studies

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Rediscovery of Chaetostomus setosus Boulenger 1887 (Siluriformes, Loricariidae), and assessment of the external characters used for determination of genera within the Chaetostoma group

Provenzano, Francisco (2018): Rediscovery of Chaetostomus setosus Boulenger 1887 (Siluriformes, Loricariidae), and assessment of the external characters used for determination of genera within the Chaetostoma group. Zootaxa 4378 (3): 397-413, DOI: https://doi.org/10.11646/zootaxa.4378.3.

Cordylancistrus nephelion Provenzano & Milani, 2006, new species

Cordylancistrus nephelion new species Figs. 1–2, Table 1 Holotype: MBUCV­V­ 21800, 129.1 mm SL; Venezuela, Caribbean Sea basin, Tuy River system, Mesia River, tributary of the Guare River, near Village Corocito, approximately 10 ° 12 'N, 67 °05'W; N. Padilla and H. Camejo; 26 January 1992. Paratypes: All from Venezuela, Caribbean Sea basin, Tuy River system. Miranda State: MBUCV­V­21801, 1 ex., 121.2 mm SL; collected with the holotype. MBUCV­V­ 12526, 1 ex., 61.0 mm SL; Grande River approximately 500 m upstream from its mouth in Santa Cruz River, a tributary of Taguaza River, Guatopo National Park, approx. 10 °05'N, 66 ° 29 'W; R. Royero and party; 0 1 March 1981. MBUCV­V­16382, 1 ex., 55.2 mm SL; Mesia River, tributary of the Guare River, Paso del Viento, near the road to Tácata, approx. 10 ° 12 'N, 67 °02'W; N. Padilla and L. Aguana; 30 January 1992. MBUCV­V­21806, 1 ex., 31.1 mm SL; Cagua River, Boca de Cagua, approximately 10 km E of Village Guayas, approx. 10 ° 14 'N 67 °07'W; R. Royero, F. Gil and C. Navarrese, 0 6 April 1991. MBUCV­V­ 27872, 1 ex, 76.4 mm SL; Mesia River, tributary of the Guare River, Pozo El Cirilo, near Village El Salado, approx. 10 ° 13 'N 67 °03'W; N. Padilla and E. Camejo; 29 May 1994. Aragua State: MBUCV­V­22700, 1 ex., 75.9 mm SL; Quebrada Agua Amarilla, a tributary of the Cagua River, Village Agua Amarilla, SE of Tejerias, approx. 10 ° 12 'N, 67 °03'W; N. Padilla; 23 February 1992. Diagnosis. Cordylancistrus nephelion can be distinguished from the other species assigned to its genus by its unique color pattern. Head and body blackish to greenish brown with white irregular spots. Abdomen uniformly white. All fins with whitish spots that simulate bands. Description. Morphometric data are given in Table 1. Head wide and slightly depressed. Snout edge covered with small plates, its contour oval. Eyes in dorsal position, dorsal edge of the orbits slightly raised, small odontodes found around orbits. Interorbital space flat. Posterior edge of the supraoccipital without a fleshy keel. Mouth wide, lips papillose, papillae of the anterior lip slightly larger. Edge of the posterior lip with marked undulations. Maxillary barbels very short and joined to lower lip by a fleshy flap, leaving tip of barbel free. Premaxilla and dentary enlarged. Inside mouth behind premaxilla with three to five larger papillae. Also behind the dentary three to five larger and smooth papillae present that increase in size toward center of mouth (Fig. 2). Teeth numerous, 49 to 105 teeth on each premaxilla and 53 to 129 on each dentary. Teeth are very thin and elongated, with apex curved toward interior of mouth. Teeth bifurcate, one lobe slightly longer than other, both tips are pointed. Tooth apex yellowish, stalk whitish. Interopercular hypertrophied evertible odontodes vary in size; longest odontode sometimes reaches the cleithrum but surpasses it in only one specimen. Hypertrophied odontodes vary in number from six on smallest specimen to 25 on the largest. Body robust and relatively deep. Caudal peduncle compressed. Lateral plates of the body without spiny keels. Lateral line plates 23 to 24. Post­anal plates 10 to 11. Inter­dorsal plates six, the last with a slight keel. Ventral surface of body naked to origin of anal fin. Dorsal fin I 8. Pectoral fin I 6, pectoral spine relatively short, reaching one­third length of pelvic spine or less. In all examined specimens, pectoral spine with odontodes on posterodorsal surface. Anal fin with four branched rays, three on one specimen. Pelvic fin I 5. Caudal fin I 14 I, obliquely truncate. Color. In specimens preserved in 70 % ethanol head and body color varies from blackish to greenish brown with white irregular spots; abdomen uniformly white. Dorsal surface of head with small spots that become larger posteriorly. Spots along body approximately as wide as the eye; in some cases two or more spots unite to form a spot of greater size. Spine and branched rays of dorsal fin with four to five whitish spots. Interradial membrane with irregular translucent spots, more evident towards the distal margin. In largest specimens (121 and 129 mm SL), pectoral­fin and pelvic­fin spine have six to seven whitish spots and branched rays have five to six, while in smaller specimens (76.4 mm SL or less) spines with four to five and branched rays with three to four. Interradial membrane hyaline. Anal fin generally whitish with dark distal border. Adipose fin with whitish band. Caudal­fin spines with six to seven whitish spots and branched rays with four to six. Interradial membrane with pattern similar to dorsal fin. Range. The specimens of Cordylancistrus nephelion were captured in three tributaries of the Tuy River: the Cagua River, the Mesia River (a tributary of the Guare River) and the Santa Cruz River (a tributary of the Taguaza River) at 40 km, 55 km and 130 km east of the headwaters of the Tuy River respectively (Fig. 3). This distribution suggests that the species may be present throughout the Tuy River basin. The species seems to inhabit small rivers of the north slope of the Serranía del Interior, Cordillera de La Costa. These rivers have transparent waters, with moderate to strong flow and a temperature of 15 ° to 20 ° C. The bottom generally consists of stone, gravel and sand. The predominant vegetation in this mountainous area is cloud forest. An exhaustive review of the Venezuelan fish collections shows that the geographic distribution of the three species of Cordylancistrus present in the country is restricted and disjunct. Cordylancistrus torbesensis inhabits the foothill rivers of the south slope of the Cordillera de Mérida; C. perijae is found in rivers of the eastern slope, north of the Sierra of Perijá and C. nephelion inhabits the Tuy River basin, in rivers of the north slope of the Serranía of the Interior, Cordillera de La Costa (Fig. 3). Etymology. The name of the species is taken from the Greek word nephelion, meaning cloudlike spots, in reference to the color pattern of the species.Published as part of Provenzano, Francisco & Milani, Nadia, 2006, Cordylancistrus nephelion (Siluriformes, Loricariidae), a new and endangered species of suckermouth armored catfish from the Tuy River, north­central Venezuela, pp. 29-41 in Zootaxa 1116 on pages 31-35, DOI: 10.5281/zenodo.17164