RESUMEN
Container-based virtualization is becoming a de facto way to build and deploy applications because of its simplicity and convenience. Kubernetes is a well-known open-source project that provides an orchestration platform for containerized applications. An application in Kubernetes can contain multiple replicas to achieve high scalability and availability. Stateless applications have no requirement for persistent storage; however, stateful applications require persistent storage for each replica. Therefore, stateful applications usually require a strong consistency of data among replicas. To achieve this, the application often relies on a leader, which is responsible for maintaining consistency and coordinating tasks among replicas. This leads to a problem that the leader often has heavy loads due to its inherent design. In a Kubernetes cluster, having the leaders of multiple applications concentrated in a specific node may become a bottleneck within the system. In this paper, we propose a leader election algorithm that overcomes the bottleneck problem by evenly distributing the leaders throughout nodes in the cluster. We also conduct experiments to prove the correctness and effectiveness of our leader election algorithm compared with a default algorithm in Kubernetes.
RESUMEN
The aim of this study is to identify and characterize virus isolates (which are named for Bacgiang Agriculture and Forestry University [BAFU]) from diseased Cherry Valley duck and mule duck flocks and investigate the damage caused by a novel parvovirus-related virus (DuPV) to tissues and organs, including the brain, cerebellum, kidney, liver, lung, spleen, and spinal cord. The results of phylogenetic analysis show that DuPV-BAFU evolved from a goose lineage and duck parvoviruses rather than from Muscovy duck parvoviruses. In the genetic lineages, DuPVs were identified from the DuPV samples analyzed, and DuPV-BAFU was found to be closely clustered with two known goose origin parvoviruses (GPVa2006 and GPV1995) and a duck GPVs. Finally, structural modeling revealed that DuPV-BAFU and the closely related viruses GPVa2006 and GPV1995 possessed identical clusters of receptor-interacting amino acid residues in the VP3 protein, a major determinant of viral receptor binding and host specificity. Significantly, these three viruses differed from DuPVs, Muscovy duck parvoviruses, and other goose parvoviruses at these positions. These results also demonstrated that DuPV-BAFU represents a new variant of goose-origin parvovirus that currently circulates in ducklings and causes beak atrophy and dwarfism syndrome, as noted in the previous reports in Europe, Taiwan, and China. This new finding highlights the need for future surveillance of DuPV-BAFU in waterfowl in order to gain a better understanding of both the evolution and the biology of this emerging parvovirus in waterfowl.
Identificación molecular y patogenicidad de un nuevo parvovirus de ganso de origen en pato aislado del síndrome de atrofia del pico y enanismo de las aves acuáticas en el norte de Vietnam. El objetivo de este estudio es identificar y caracterizar aislados de virus detectados en la Universidad de Agricultura y Silvicultura de Bacgiang (BAFU) de parvadas de patos enfermos Cherry Valley e híbridos y también investigar el daño causado por un nuevo virus relacionado con parvovirus del pato (DuPV) en tejidos y órganos, incluidos el cerebro, el cerebelo, los riñones, el hígado, los pulmones, el bazo y la médula espinal. Los resultados del análisis filogenético mostraron que el virus DuPV-BAFU evolucionó a partir de un linaje de parvovirus de patos y gansos en lugar del parvovirus de patos reales. En los linajes genéticos, se identificaron virus DuPV a partir de las muestras de DuPV analizadas, y se encontró que el DuPV-BAFU estaba estrechamente agrupado con dos parvovirus conocidos de origen de ganso (GPVa2006 y GPV1995) y con parvovirus de pato. Finalmente, el modelado estructural reveló que el virus DuPV-BAFU y los virus estrechamente relacionados GPVa2006 y GPV1995 poseían grupos idénticos de residuos de aminoácidos que interactúan con el receptor en la proteína VP3, que es un determinante importante de la unión al receptor viral y la especificidad del huésped. Significativamente, estos tres virus diferían de los DuPV, los parvovirus del pato real y de otros parvovirus del ganso en estas posiciones. Estos resultados también demostraron que el virus DuPV-BAFU representa una nueva variante del parvovirus de origen ganso que actualmente circula en patitos y causa atrofia del pico y síndrome de enanismo, como se señaló en reportes anteriores en Europa, Taiwán y China. Este nuevo hallazgo destaca la necesidad de una vigilancia futura para el virus DuPV-BAFU en las aves acuáticas para comprender mejor tanto la evolución como la biología de este parvovirus emergente en las aves acuáticas.
Asunto(s)
Enanismo , Infecciones por Parvoviridae , Parvovirus , Enfermedades de las Aves de Corral , Aminoácidos , Animales , Atrofia/veterinaria , Pico/patología , Patos , Enanismo/patología , Enanismo/veterinaria , Infecciones por Parvoviridae/veterinaria , Parvovirinae , Parvovirus/genética , Filogenia , Vietnam , VirulenciaRESUMEN
PURPOSE: To analyse the association of body weight with hospital mortality of adult patients supported with veno-venous extracorporeal membrane oxygenation (VV ECMO). METHODS: Retrospective analysis of the international Extracorporeal Life Support Organization (ELSO) registry. Univariate and multivariable logistic regression analyses were used to estimate the odds ratio (OR) of hospital death for each body weight quartile. Adjustment was made for demographic, physiologic and ECMO-related characteristics. We undertook a similar analysis for the subgroup of patients with confirmed H1N1 infection on VV ECMO. RESULTS: The study group consisted of 1,334 adult patients supported with VV ECMO between 2005 and 2011 with a median (Q1, Q3) body weight of 80 kg (69, 101 kg). Univariate analysis identified increased body weight to be associated with a reduced risk of death. In multivariable analysis, only age greater than 53 years, primary diagnosis other than pneumonia and intubation time longer than 3 days prior to initiation of ECMO were independent risk factors for mortality, whereas the association between high body weight and adjusted risk of death (OR 0.73, 95% CI 0.52-1.04, P = 0.08) was no longer statistically significant. The body weight of the 196 patients with confirmed H1N1 infection was significantly higher than that of the remaining study group. Body weight was not significantly associated with risk of death for these patients either (univariate OR for Q4 vs. Q1: 0.75, 95% CI 0.33-1.72, P = 0.49). CONCLUSIONS: Increased body weight was not a risk factor for hospital mortality in adult patients who required support with VV ECMO. High body weight should therefore not be regarded as a contraindication to initiation of VV ECMO in adult patients. Data collection and reporting that include patient height in addition to body weight would facilitate future research into the association of obesity with outcome of ECMO patients.
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Peso Corporal , Oxigenación por Membrana Extracorpórea/mortalidad , Oxigenación por Membrana Extracorpórea/métodos , Mortalidad Hospitalaria , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sistema de Registros , Estudios Retrospectivos , Factores de RiesgoRESUMEN
PURPOSE: A prospective multicentre cohort study was conducted to determine the prevalence of hypovitaminosis D in adult critically ill patients, to characterize alterations in the parathyroid hormone (PTH)-vitamin D-calcium axis and to explore associations between hypovitaminosis D and adverse clinical outcomes. METHODS: Demographic, disease severity scores and clinical outcome data were collected in 100 consecutive patients with expected intensive care unit (ICU) admission of at least 2 days. Levels of 25-hydroxyvitamin D (25-OH-D), 1,25-dihydroxyvitamin D (1,25-(OH)(2)-D), PTH and ionized calcium were measured on days 1, 3 and on day 7 or ICU discharge. RESULTS: The prevalence of vitamin D insufficiency (25 nmol/L ≤ 25-OH-D ≤ 50 nmol/L) and deficiency (25-OH-D < 25 nmol/L) were 54 and 24 %, respectively, and levels did not recover during ICU stay. Admission 25-OH-D levels correlated with 1,25-(OH)(2)-D (R = 0.61, p = 0.001), Simplified Acute Physiology Score (SAPS-II) (R = -0.3, p = 0.01), Acute Physiology and Chronic Health Evaluation (APACHE-II) scores (R = -0.2, p = 0.05), but not calcium (R = 0.16, p = 0.11) or PTH (R = -0.11, p = 0.31) levels. Vitamin D deficiency was associated with fewer hospital-free days, OR 3.15 (1.18-8.43) in univariate analysis. Secondary hyperparathyroidism (PTH > 7 pmol/L) was observed in 37.5 % of hypocalcaemic and 32.5 % of vitamin D insufficient/deficient patients, and was associated with higher SAPS-II [43 (31.3-60) vs. 36 (30-43), p = 0.03]. CONCLUSIONS: Hypovitaminosis D and secondary hyperparathyroidism are highly prevalent in critically ill patients. Low vitamin D status persists during ICU stay and is associated with worse disease severity and fewer hospital-free days.