Numerical simulation of centrifugal pumps

The power computers increase and the specific calculation software development have made possible, nowadays, the numerical simulation of flow and energy transfer inside the turbomachinery. To teach Fluid Mechanics is not easy not only for the professors but also for the students because the theoretical part must be complemented with a technical part where students can see the phenomena. However, specially in hydraulic turbomachinery, we canít see the phenomena except if we have a specific material, for example a PIV. Even if we would have this material, the access to specific parts of turbomachinery is not possible due to its constructive layout. The use of numerical simulation tools allows us to obtain data in inaccessible positions for the experimentation, as well as the study of unusual or dangerous performances. With the numerical simulation, the pressure fluctuation at any point of the pump can be easily obtained. Other important results are the radial forces on the impeller, which have a significant variation with the working points. One of the advantages of this kind of modelling is the ease to carry out changes in the geometry, parametric studies and analysis of anomalous operation conditions

Time travel paradoxes, path integrals, and the many worlds interpretation of quantum mechanics

We consider two approaches to evading paradoxes in quantum mechanics with closed timelike curves (CTCs). In a model similar to Politzer's, assuming pure states and using path integrals, we show that the problems of paradoxes and of unitarity violation are related; preserving unitarity avoids paradoxes by modifying the time evolution so that improbable events bewcome certain. Deutsch has argued, using the density matrix, that paradoxes do not occur in the "many worlds interpretation". We find that in this approach account must be taken of the resolution time of the device that detects objects emerging from a wormhole or other time machine. When this is done one finds that this approach is viable only if macroscopic objects traversing a wormhole interact with it so strongly that they are broken into microscopic fragments.Comment: no figure

Eleven-month longitudinal study of antibodies in SARS-CoV-2 exposed and naïve primary health care workers upon COVID-19 vaccination

We evaluated the kinetics of antibody responses to Two years into the COVID-19 pandemic and 1 year after the start of vaccination rollout, the world faced a peak of cases associated with the highly contagious Omicron variant of concern (VoC) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) and nucleocapsid (N) antigens over five cross-sectional visits (January-November 2021), and the determinants of pre-booster immunoglobulin levels, in a prospective cohort of vaccinated primary health care workers in Catalonia, Spain. Antibodies against S antigens after a full primary vaccination course, mostly with BNT162b2, decreased steadily over time and were higher in pre-exposed (n = 247) than naive (n = 200) individuals, but seropositivity was maintained at 100% (100% IgG, 95.5% IgA, 30.6% IgM) up to 319 days after the first dose. Antibody binding to variants of concern was highly maintained for IgG compared to wild type but significantly reduced for IgA and IgM, particularly for Beta and Gamma. Factors significantly associated with longer-term antibodies included age, sex, occupation, smoking, adverse reaction to vaccination, levels of pre-vaccination SARS-CoV-2 antibodies, interval between disease onset and vaccination, hospitalization, oxygen supply, post COVID and symptomatology. Earlier morning vaccination hours were associated with higher IgG responses in pre-exposed participants. Symptomatic breakthroughs occurred in 9/447 (2.01%) individuals, all among naive (9/200, 4.5%) and generally boosted antibody responses. Additionally, an increase in IgA and/or IgM seropositivity to variants, and N seroconversion at later time points (6.54%), indicated asymptomatic breakthrough infections, even among pre-exposed. Seropositivity remained highly stable over almost a year after vaccination. However, gradually waning of anti-S IgGs that correlate with neutralizing activity, coupled to evidence of an increase in breakthrough infections during the Delta and Omicron predominance, provides a rationale for booster immunization

Paratextual subversion: Herrera and his poetry in the anotaciones

The year 1580 saw the publication of the Anotaciones a las obras de Garcilaso de la Vega by the critic and poet Fernando de Herrera (c. 1534–97). This study develops previous scholarship on the paratextual strategies employed by Herrera, especially with regard to the inclusion of his own poetry within the Anotaciones. Two Garcilasian sonnets, ‘D’aquella vista pura i ecelente’ (VIII) and ‘Si para refrenar este desseo’ (XII), in conjunction with Herrera’s poetic responses, lie at the heart of this investigation, representing two respectively dominant cultural currents of the period: Neoplatonism and Classical mythography. It will be shown how Herrera exploits Counter-Reformation attitudes towards secularity and mythography to engage in a critique that goes deeper than the attacks previously noted by Navarrete’s 1991 study. Indeed, Herrera’s lyric occupies a central role in a complete re-evaluation of Garcilasian lyric that not only moves to subvert the supremacy of the Toledan but also the hegemonic rule of intellectuals from Castile. Herrera presents himself as a learned Andalusian model for Neoplatonic poetics and as the model for imitation for Spanish letters in the wake of the Counter-Reformation. En 1580 el poeta y crítico Fernando de Herrera (c. 1534–97) publicó sus Anotaciones a las obras de Garcilaso de la Vega. Este artículo desarrolla estudios anteriores sobre esta obra en relación con las estrategias paratextuales empleadas por Herrera, sobre todo por lo que respecta a la inclusión de su propia poesía en el texto de las Anotaciones. Este trabajo se centra en dos sonetos de Garcilaso, ‘D’aquella vista pura i ecelente’ (VIII) y ‘Si para refrenar este deseo’ (XII), en conjunción con otros tantos textos poéticos de Herrera, teniendo en cuenta sus deudas con dos corrientes culturales contemporáneas: el neoplatonismo y la mitología clásica. Las actitudes hacia el amor neoplatónico y la mitología fueron explotadas por Herrera de una manera más profunda de lo que se suele creer. En efecto, la poesía de Herrera ocupa un papel central en la reevaluación completa de Garcilaso que no sólo subvierte la posición del poeta en el canon literario sino también la hegemonía de los intelectuales de Castilla. Herrera se presenta como un andaluz sabio y defensor de la poesía neoplatónica y como el modelo de referencia para la imitación poética en la nueva era que se abre con la Contrarreforma.This is the author accepted manuscript. The final version is available from Maney via http://dx.doi.org/10.1179/1468273715Z.00000000012

Incidence rates of narcolepsy diagnoses in Taiwan, Canada, and Europe: The use of statistical simulation to evaluate methods for the rapid assessment of potential safety issues on a population level in the SOMNIA study

BACKGROUND & OBJECTIVES: Vaccine safety signals require investigation, which may be done rapidly at the population level using ecological studies, before embarking on hypothesis-testing studies. Incidence rates were used to assess a signal of narcolepsy following AS03-adjuvanted monovalent pandemic H1N1 (pH1N1) influenza vaccination among children and adolescents in Sweden and Finland in 2010. We explored the utility of ecological data to assess incidence of narcolepsy following exposure to pandemic H1N1 virus or vaccination in 10 sites that used different vaccines, adjuvants, and had varying vaccine coverage.METHODS: We calculated incidence rates of diagnosed narcolepsy for periods defined by influenza virus circulation and vaccination campaign dates, and used Poisson regression to estimate incidence rate ratios (IRRs) comparing the periods during which wild-type virus circulated and after the start of vaccination campaigns vs. the period prior to pH1N1 virus circulation. We used electronic health care data from Sweden, Denmark, the United Kingdom, Canada (3 provinces), Taiwan, Netherlands, and Spain (2 regions) from 2003 to 2013. We investigated interactions between age group and adjuvant in European sites and conducted a simulation study to investigate how vaccine coverage, age, and the interval from onset to diagnosis may impact the ability to detect safety signals.RESULTS: Incidence rates of narcolepsy varied by age, continent, and period. Only in Taiwan and Sweden were significant time-period-by-age-group interactions observed. Associations were found for children in Taiwan (following pH1N1 virus circulation) and Sweden (following vaccination). Simulations showed that the individual-level relative risk of narcolepsy was underestimated using ecological methods comparing post- vs. pre-vaccination periods; this effect was attenuated with higher vaccine coverage and a shorter interval from disease onset to diagnosis.CONCLUSIONS: Ecological methods can be useful for vaccine safety assessment but the results are influenced by diagnostic delay and vaccine coverage. Because ecological methods assess risk at the population level, these methods should be treated as signal-generating methods and drawing conclusions regarding individual-level risk should be avoided

Inhibidors de l’adenosina difosfat en pacients amb síndrome coronària aguda sense elevació del segment ST

Antiagregante plaquetario; Síndrome coronario agudo; InhibidoresAntigregant plaquetari; Síndrome coronària aguda; InhibidorsAntiplatelet drug; Acute coronary syndrome; InhibitorsAquest document conté les recomanacions d’ús dels antiagregants plaquetaris antagonistes dels receptors de l’adenosina difosfat (ADP) en pacients amb síndrome coronària aguda sense elevació persistent del segment ST (SCASEST). L’objectiu d’aquest document ha estat la generació de recomanacions d’ús per a clopidogrel, prasugrel i ticagrelor en pacients amb SCASEST, considerant els diferents escenaris clínics en els quals els pacients es poden trobar en funció del seu perfil de risc. Aquestes recomanacions estan adreçades a reduir la variabilitat en el maneig farmacològic d’aquests pacients i a homogeneïtzar els criteris d’ús de les tres alternatives antiagregants disponibles en el nostre entorn

Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

Narcolepsy and adjuvanted pandemic influenza A (H1N1) 2009 vaccines – Multi-country assessment

Background: In 2010, a safety signal was detected for narcolepsy following vaccination with Pandemrix, an AS03-adjuvanted monovalent pandemic H1N1 influenza (pH1N1) vaccine. To further assess a possible association and inform policy on future use of adjuvants, we conducted a multi-country study of narcolepsy and adjuvanted pH1N1 vaccines. Methods: We used electronic health databases to conduct a dynamic retrospective cohort study to assess narcolepsy incidence rates (IR) before and during pH1N1 virus circulation, and after pH1N1 vaccination campaigns in Canada, Denmark, Spain, Sweden, Taiwan, the Netherlands, and the United Kingdom. Using a case-control study design, we evaluated the risk of narcolepsy following AS03- and MF59-adjuvanted pH1N1 vaccines in Argentina, Canada, Spain, Switzerland, Taiwan, and the Netherlands. In the Netherlands, we also conducted a case-coverage study in children born between 2004 and 2009. Results: No changes in narcolepsy IRs were observed in any periods in single study sites except Sweden and Taiwan; in Taiwan incidence increased after wild-type pH1N1 virus circulation and in Sweden (a previously identified signaling country), incidence increased after the start of pH1N1 vaccination. No association was observed for Arepanrix-AS03 or Focetria-MF59 adjuvanted pH1N1 vaccines and narcolepsy in children or adults in the case-control study nor for children born between 2004 and 2009 in the Netherlands case-coverage study for Pandemrix-AS03. Conclusions: Other than elevated narcolepsy IRs in the period after vaccination campaigns in Sweden, we did not find an association between AS03- or MF59-adjuvanted pH1N1 vaccines and narcolepsy in children or adults in the sites studied, although power to evaluate the AS03-adjuvanted Pandemrix brand vaccine was limited in our study