A Generic Undo Support for State-Based CRDTs

CRDTs (Conflict-free Replicated Data Types) have properties desirable for large-scale distributed systems with variable network latency or transient partitions. With CRDT, data are always available for local updates and data states converge when the replicas have incorporated the same updates. Undo is useful for correcting human mistakes and for restoring system-wide invariant violated due to long delays or network partitions. There is currently no generally applicable undo support for CRDTs. There are at least two reasons for this. First, there is currently no abstraction that we can practically use to capture the relations between undo and normal operations with respect to concurrency and causality. Second, using inverse operations as the existing partial solutions, the CRDT designer has to hard-code certain rules and design a new CRDT for almost every operation that needs undo support. In this paper, we present an approach to generic support of undo for CRDTs. The approach consists of two major parts. We first work out an abstraction that captures the semantics of concurrent undo and redo operations through equivalence classes. The abstraction is a natural extension of undo and redo in sequential applications and is straightforward to implement in practice. By using this abstraction, we then device a mechanism to augment existing CRDTs. The mechanism provides an “out of the box” support for undo without the involvement of the CRDT designers. We also present a practical application of the approach in collaborative editing

Respuesta serológica a la vacunación contra brucelosis en bovinos provenientes de un rebaño libre vacunados con dos dosis de vacuna Cepa RB-51

A prospective study was carried out in order to determine the serological response to the official tests used in Chile for the detection of bovine brucellosis which are Rose Bengal (RB), Complement Fixation (CF) and Competing Elisa (C-ELISA), in adult cows vaccinated with two doses of vaccine strain RB-51 from a brucellosis free herd as certified by the Servicio Agrícola y Ganadero (SAG) of the Ministry of Agriculture of Chile. A total of 100 female bovines older than 18 months were selected in order to be 90% confident that the proportion of positives in cows vaccinated twice would not exceed 2.95% if all collected serum samples remained negative. The animals were vaccinated subcutaneously with 2 cc of vaccine strain RB-51 in doses of 1-3.4 x 1010 ufc with an interval of 30 days between the first and the second application; the date of the first vaccination was the day 0 of study. Serum samples were taken the days 0, 30 and 60. Samples were processed in the Laboratory of Reference for Bovine Brucellosis of the SAG, Osorno, X Region, Chile. None of the vaccinated cows showed serological reaction due to administration of two doses of RB-51 vaccine detected by routine tests for bovine brucellosis.  Se realizó una encuesta prospectiva con la finalidad de determinar la respuesta serológica a las pruebas oficiales aplicadas en Chile para la detección de brucelosis bovina que son Rosa de Bengala (RB), Fijación de Complemento (FC) y Elisa de Competencia (C-Elisa), en hembras adultas vacunadas con dos dosis de vacuna Cepa RB-51 provenientes de un rebaño libre de la enfermedad con certificación vigente otorgada por el Servicio Agrícola y Ganadero (SAG) del Ministerio de Agricultura de Chile. Se seleccionaron 100 hembras bovinas mayores de 18 meses con la finalidad de tener una confianza de un 90% de que la proporción de positivos no será mayor a un 2,95% si todos los animales muestreados resultan negativos. Los bovinos fueron vacunados vía subcutánes con vacuna Cepa RB-51 en dosis de 1-3.4 x 1010 UFC con una diferencia de 30 días entre la primera y segunda aplicación; la fecha de la primera vacunación correspondió al día cero del estudio. Los días 0, 30 y 60 se tomaron muestras de 10 ml de sangre por venopunción coccígea de cada animal seleccionado. Las muestras se procesaron en el Laboratorio de Referencia de Brucelosis Bovina del SAG, Osorno, X Región, Chile. Ningún animal presentó reacción serológica atribuible a la vacunación con RB-51 que puedan interferir con las pruebas diagnósticas actualmente utilizadas para la detección de la brucelosis bovina. &nbsp

GIS Use in Oral Rabies Vaccine Programs

Frequent human and domestic animal exposures to rabid wildlife have raised the public\u27s awareness, leading to an increase in the number of wildlife submissions for rabies testing as well as an increase in the number of people requiring post exposure prophylaxis treatment. During 1998 and 1999, the Health and Human Services Department of a densely populated urban/suburban county in Virginia received a total of 955 animal submissions for rabies testing. Wildlife accounted for 714 of the submissions. Seventy-nine of the submitted wildlife were found dead, 445 were killed or euthanized for testing (190 unknown). Of the wildlife submissions,152 (21%) were positive, including 100 of 178 raccoons submitted. Human exposure, potentially requiring post-exposure prophylaxis, was recorded in 22 positive and 334 negative rabies submissions. Information was not available for 9 positive and 135 negative submissions; human exposure did not occur with the remaining submissions. To reduce the public\u27s risk of exposure to rabid animals, the County is developing a program to distribute oral rabies vaccine to raccoons. To increase the precision of vaccine delivery to raccoons, we propose the use of geographical information systems (GIS) as a method for selecting vaccination sites. Results from trapping and tracking studies, along with hydrographic and vegetation data, were utilized in the development of GIS generated vaccine distribution maps. Also factored in was human activity, commerce, residential housing density, competition by companion animals for vaccine bait, the location of refuse facilities, and property ownership. It is expected that this GIS supported approach will improve the efficiency of the program by lessening the cost while increasing the number of raccoons immunized. The resulting decrease in the incidence of rabies will lead to fewer human exposures to rabid wildlife, a decrease in the number of healthy wildlife euthanized for testing, and a decrease in the number of people requiring post-exposure prophylaxis treatment

Respuesta serológica y tiempo de saneamiento en rebaños bovinos con brucelosis vacunados con Cepa 19 o Cepa RB-51; Xª Región, Chile

The serologic response to brucellosis vaccination and the time to eradication of brucellosis from herds were compared in dairy cattle vaccinated with either vaccine strains 19 or RB-51. Serologic records from 79 herds from the Province of Valdivia, 10th region of Chile, were evaluated. Herds had been enrolled in the Bovine Brucellosis Eradication Program between 1996 and 1999 and were free of brucellosis at the time of this evaluation. Twenty-six herds, with 540 cows and a pre-vaccination seroprevalence of 14.1%, were vaccinated with brucellosis vaccine strain 19, and 53 herds, with 1104 cows and a pre-vaccination seroprevalence of 7.6% received vaccine strain RB-51. Blood sera were collected at various time intervals and tested for antibodies to Brucella spp. using the card and complement fixation tests. Seroprevalences, time interval from first detection of disease to certification of freedom from infection, and various time intervals within this time frame, number of tests and time intervals between tests were compared. Sixty-six of 369 previously negative cows vaccinated with strain 19 serconverted, but none of 917 previously negative cows vaccinated with strain RB-51 seroconverted. Time to certification ranged from 304 to 1025 days for herds vaccinated with strain 19 (median 481 days), and from 140 to 753 days for herds vaccinated with strain RB-51 (median 401 days; p=0.003). Herd size, heifer replacement policies, type of veterinary assistance and severity of clinical brucellosis signs on farms did not affect any of the time variables. Vaccine strain 19 herds were tested on average 4.4 times, while vaccine strain RB-51 herds were tested only 3.4 times (p<0.001) during the control period; time intervals between tests were not different (strain 19: 126 days; strain RB-51: 121 days; p=0.60). Vaccine strain RB-51 and control policies associated with its use shortened the duration to certification of freedom from disease and required less resources for samply and testy than use of vaccine strain 19.Se comparó la respuesta serológica y el tiempo de saneamiento en rebaños bovinos con brucelosis, vacunados con vacuna Cepa 19 o Cepa RB-51. Se estudiaron los registros serológicos de 79 rebaños de la provincia de Valdivia, Xa región de Chile. Los rebaños se habian incorporado al Programa de Erradicacion de Brucelosis Bovina entre 1996 y 1999, y al momento de este estudio se encontraban bajo la condicion de “rebaño saneado”. Veintiséis rebaños, con 540 vacas y una seroprevalencia inicial de 14.1%, fueron vacunados con la vacuna Cepa 19 y 53 rebaños, con 1104 vacas y una seroprevalencia inicial de 7.6%, recibieron Cepa RB-51. Periódicamente se colectaron muestras de suero sanguíneo y se examinaron para anticuerpos de Brucella spp. usando las pruebas de Rosa de Bengala y Fijacion de Complemento. Se evaluaron las seroprevalencias, el tiempo de saneamiento y los intervalos de tiempo dentro de éste, el número de exámenes y el lapso de tiempo entre los exámenes. Sesenta y seis de 369, vacas, previamente negativas vacunadas con Cepa 19, seroconvirtieron, pero ninguna de las 917 vacas vacunadas con RB-51 seroconvirtió. El tiempo de saneamiento para los rebaños vacunados con Cepa 19 fluctuó desde 304 a 1025 días (mediana 481 días), y para los rebaños vacunados con Cepa RB-51 desde 140 a 753 días (mediana 401 días; p = 0.003). El tamaño del rebaño, las políticas de reemplazo, el tipo de asistencia veterinaria y la severidad de los signos clínicos de brucelosis no afectaron los lapsos de tiempo. Los rebaños con Cepa 19 fueron muestreados en promedio 4.4 veces y los rebaños con Cepa RB-51 fueron muestreados solo 3.4 veces (p < 0.001); el lapso entre muestreos no presentó diferencia significativa (Cepa 19: 121 días; Cepa RB-51: 126 días; p > 0.05). El uso de la vacuna Cepa RB-51 y las políticas de control asociadas a su uso reducen el tiempo de saneamiento y el numero de exámenes, a diferencia de la vacuna Cepa 19. &nbsp

Two amino acid mutations in the capsid protein of type 2 porcine circovirus (PCV2) enhanced PCV2 replication in vitro and attenuated the virus in vivo

Porcine circovirus type 2 (PCV2) is the primary causative agent of postweaning multisystemic wasting syndrome (PMWS) in pigs. To identify potential genetic determinants for virulence and replication, we serially passaged a PCV2 isolate 120 times in PK-15 cells. The viruses harvested at virus passages 1 (VP1) and 120 (VP120) were biologically, genetically, and experimentally characterized. The PCV2 VP120 virus replicated in PK-15 cells to a titer similar to that of the PK-15 cell line-derived nonpathogenic PCV1 but replicated more efficiently than PCV2 VP1 with a difference of about 1 log unit in the titers. The complete genomic sequences of viruses at passages 0, 30, 60, 90, and 120 were determined. After 120 passages, only two nucleotide mutations were identified in the entire genome, and both were located in the capsid gene: the mutations were located at nucleotide positions 328 (C328G) and 573 (A573C). The C328G mutation, in which a proline at position 110 of the capsid protein changed to an alanine (P110A), occurred at passage 30 and remained in the subsequent passages. The second mutation, A573C, resulting in a change from an arginine to a serine at position 191 (R191S), appeared at passage 120. To experimentally characterize the VP120 virus, 31 specific-pathogen-free pigs were randomly divided into three groups. Ten pigs in group 1 received phosphate-buffered saline as negative controls. Each pig in group 2 (11 pigs) was inoculated intramuscularly and intranasally with 10(4.9) 50% tissue culture infective doses (TCID(50)) of PCV2 VP120. Each pig in group 3 (10 pigs) was similarly inoculated with 10(4.9) TCID(50) of PCV2 VP1. Viremia was detected in 9 of 10 pigs in the PCV2 VP1 group with a mean duration of 3 weeks, but in only 4 of 11 pigs in the PCV2 VP120 group with a mean duration of 1.6 weeks. The PCV2 genomic copy numbers in serum in the PCV2 VP1 group were significantly higher than those in the PCV2 VP120 group (P < 0.0001). Gross and histopathologic lesions in pigs inoculated with PCV2 VP1 were more severe than those inoculated with PCV2 VP120 at both day 21 and 42 necropsies (P = 0.0032 and P = 0.0274, respectively). Taken together, the results from this study indicated that the P110A and R191S mutations in the capsid of PCV2 enhanced the growth ability of PCV2 in vitro and attenuated the virus in vivo. This finding has important implications for PCV2 vaccine development

MUTE: A Peer-to-Peer Web-based Real-time Collaborative Editor

International audienceReal-time collaborative editing allows multiple users to edit shared documents at the same time from different places. Existing real-time collaborative editors rely on a central authority that stores user data which is a perceived privacy threat. In this paper, we present MultiUser Text Editor (MUTE), a peer-to-peer web-based real-time collaborative editor without central authority disadvantages. Users share their data with the collaborators they trust without having to store their data on a central place. MUTE features high scalability and supports offline and ad-hoc collaboration

Emergency interventions for cardiogenic shock due to decompensated aortic stenosis: a systematic review and meta-analysis

Background Cardiogenic shock (CS) induced by severe aortic stenosis (AS) is a life-threatening condition with high mortality. Despite advancements in emergency interventions, the optimal treatment approach remains uncertain. Aim This study aimed to systematically review and analyse the existing evidence on outcomes of emergency transcatheter aortic valve implantation (eTAVI) and emergency balloon aortic valvuloplasty (eBAV) in CS patients. Methods A systematic literature review and meta-analysis was performed. The primary endpoint was mortality at 30 days. Secondary endpoints were in-hospital mortality, 1-year mortality, bleeding, major vascular complications, myocardial infarction, stroke, incidence of pacemaker implantation, acute kidney injury and aortic regurgitation. Results Seventeen studies were included, totalling 2811 patients. The analysis revealed a 30-day mortality pooled estimated rate for eTAVI of 19% (CI 0.17 - 0.20) and for eBAV 39% (CI 0.32 - 0.46). In-hospital mortality pooled estimated rates were 11% for eTAVI (CI 0.06 - 0.18) and for eBAV 40% (CI 0.28 - 0.54). One-year mortality pooled estimated rates for eTAVI were 29% (CI 0.20 - 0.40) and for eBAV 67% (CI 0.58 - 0.74). Pooled estimated rates of any bleeding were 12% for eTAVI (CI 0.06 - 0.20) and 15% for eBAV (CI 0.10 - 0.21). The rate of major vascular complications for eTAVI was 8% (CI 0.07 - 0.10) and 3% for eBAV (CI 0.0 - 0.23). Conclusions This meta-analysis indicates that mortality in CS due to AS remains high despite emergency interventional treatment. These findings offer critical insights for clinical decision-making optimising patient care in this critically ill population