323 research outputs found

    Optimizing MPI one-sided synchronization mechanisms on Cray's Cascade HPC systems

    Get PDF
    In this work we proposed Notified Access a new communication model that targets RDMA networks. Our focus was on optimizing producer-consumer computations, avoiding to over synchronize processes in point-to-point communications when it's not needed. We proposed a communication model in which a notification can be coupled with a single Remote Memory Access (RMA). In our model the target of an RMA operation is directly notified after the completion of a notified operation. This approach, avoiding the use of other synchronization primitives, minimizes synchronization latencies while using full hardware offload typical of high-performance networks. In order to demonstrate lower overheads than other point-to-point synchronization mechanisms, we implemented it in an open source MPI-3 library. We evaluated the performances of our implementation in a ping-pong benchmark, a computation/communication overlap benchmark and in three real-world applications: a pipeline stencil, a tree-based reduce and a task based Cholesky factorization. Our analysis shows that Notified Access is a valuable primitive for any RMA system and furthermore we show that the required hardware feature are already available in multiple state-of-the-art high-performance networks

    Equine concentrated albumin solution in the fluid therapy in horses with slight to moderate dehydration

    Get PDF
    Avaliou-se o efeito da solução concentrada de albumina eqüina diluída a 5% em solução fisiológica (SF) durante fluidoterapia em eqüinos, após indução de desidratação leve a moderada, utilizando-se cinco eqüinos adultos, sem alterações clínicas. Cada animal passou por dois protocolos de fluidoterapia: apenas com SF (metade sob pressão e metade em fluxo contínuo - grupo-controle); com solução de albumina eqüina e SF (apenas em fluxo contínuo - grupo experimental). Avaliaram-se peso, exame físico geral, hematócrito, osmolalidade plasmática, gasometria, proteína total, albumina, uréia, creatinina, Na, K, débito cardíaco e pressão arterial, e calcularam-se pressão oncótica e volume plasmático. Após a aplicação de metade da SF sob pressão nos animais do grupo-controle, as alterações no hematócrito, na proteína total, na albumina, na pressão arterial e na pressão oncótica foram semelhantes às encontradas nos do grupo experimental após aplicação apenas da solução de albumina. Conclui-se que a solução de albumina eqüina é de fácil preparação e aplicação, não demonstra efeitos deletérios na dose e velocidade utilizadas e é passível de ser utilizada como colóide na fluidoterapia na espécie eqüinaThe effect of the equine concentrated albumin solution diluted to 5% in physiologic saline solution (PSS) during fluid therapy in horses after induced slight to moderate dehydration was evaluated in five adult horses with no clinical alterations. Each animal was submitted to two fluid therapy protocols; with only PSS (half of the total volume under pressure and half in continuous flow - control-group), or with equine albumin solution and PSS (only in continuous flow - treated-group). Body weight; general physical examination, packed cell volume (PCV); plasmatic osmometry; gasometry, total protein, albumin, urea, creatinin, Na, and K, cardiac output; and arterial pressure; and calculation of the oncotic pressure and plasmatic volume were evaluated. After the administration of the first half of PSS under pressure in control group, it was observed that alterations in PCV, total protein, albumin, arterial pressure, and oncotic pressure were similar to those found in experimental group after the administration of the albumin solution. It was concluded that the equine albumin solution is easily prepared and administered, with no deleterial effects in the employed dose and speed, and it is suitable for use as a colloid in fluid therapy in equine specie

    Amazon, Google and Microsoft Solutions for IoT: Architectures and a Performance Comparison

    Get PDF
    Internet of Things (IoT) aims to connect the real world made up of devices, sensors and actuators to the virtual world of Internet in order to interconnect devices with each other generating information from the gathered data. Devices, in general, have limited computational power and limited storage capacity. Cloud Computing (CC) has virtually unlimited capacity in terms of storage and computing power, and is based on sharing resources. Therefore, the integration between IoT and CC seems to be one of the most promising solutions. In fact, many of the biggest companies that offer Cloud Services are focusing on the IoT world to offer services also in this direction to their users. In this paper we compare the three main Cloud Platforms (Amazon Web Services, Google Cloud Platform and Microsoft Azure) regarding to the services made available for the IoT. After describing the typical architecture of an IoT application, we map the Cloud-IoT Platforms services with this architecture analyzing the key points for each platform. At the same time, in order to conduct a comparative analysis of performance, we focus on a service made available by all platforms (MQTT middleware) building the reference scenarios and the metrics to be taken into account. Finally, we provide an overview of platform costs based on different loads. The aim is not to declare a winner, but to provide a useful tool to developers to make an informed choice of a platform depending on the use case

    Decrease in n-acetylaspartate following concussion may be coupled to decrease in creatine

    Get PDF
    Objectives: To assess the time course changes in brain N-acetylaspartate (NAA) and creatine (Cr) in athletes who suffered a sport-related concussion. Participants: Eleven non-consecutive concussed athletes and 11 sex and age-matched control volunteers. Main outcome measures: At 3, 15, 30 and 45 days post-injury, athletes were examined by proton Magnetic Resonance Spectroscopy (1H-MRS) for the determination of NAA,(Cr) and choline (Cho). 1H-MRS data recorded in the control group were used for comparison. Results: Compared to controls (2.18 ± 0.19), athletes showed an NAA/Cr increase at 3 (2.71 ± 0.16; p < 0.01) and 15 days (2.54 ± 0.21; p < 0.01), followed by a decrease and subsequent normalization at 30 (1.95 ± 0.16, p < 0.05) and 45 days(2.17 ± 0.20; p <0.05) post-concussion. NAA/Cho decreased at 3, 15 and 30 days post-injury (p < 0.01 compared to controls), with no differences from controls at 45 days post-concussion. Significant increase in the Cho/Cr after 3 (+33%, p < 0.01) and 15 (+31.5%, p < 0.01) days post-injury was observed, whilst no differences compared to controls were recorded at 30 and 45 days post-impact. Conclusions: This cohort of athletes indicates that concussion may cause concomitant decrease in cerebral NAA and Cr. This occurrence provokes longer time of metabolism normalization, as well as longer resolution time of concussion-associated clinical symptoms

    Hepatic resection for hepatocellular carcinoma in patients with Child–Pugh's A cirrhosis: is clinical evidence of portal hypertension a contraindication?

    Get PDF
    AbstractBackgroundAccording to international guidelines [European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD)], portal hypertension (PHTN) is considered a contraindication for liver resection for hepatocellular carcinoma (HCC), and patients should be referred for other treatments. However, this statement remains controversial. The aim of this study was to elucidate surgical outcomes of minor hepatectomies in patients with PHTN (defined by the presence of esophageal varices or a platelet count of <100 000 in association with splenomegaly) and well‐compensated liver disease.MethodsBetween 1997 and 2012, a total of 223 cirrhotic patients [stage A according to the Barcelona Clinic Liver Cancer (BCLC) classification] were eligible for this analysis and were divided into two groups according to the presence (n = 63) or absence (n = 160) of PHTN. The demographic data were comparable in the two patient groups.ResultsOperative mortality was not different (only one patient died in the PHTN group). However, patients with PHTN had higher liver‐related morbidity (29% versus 14%; P = 0.009), without differences in hospital stay (8.8 versus 9.8 days, respectively). The PHTN group showed a worse survival rate only if biochemical signs of liver decompensation existed. Multivariate analysis identified albumin levels as an independent predictive factor for survival.ConclusionsPHTN should not be considered an absolute contraindication to a hepatectomy in cirrhotic patients. Patients with PHTN have short‐ and long‐term results similar to patients with normal portal pressure. A limited hepatic resection for early‐stage tumours is an option for Child–Pugh class A5 patients with PHTN

    Impact of 24 weeks of strength training coupled to endurance training on endurance performance (HERO Dolomites 2019)

    Get PDF
    Despite reports are still equivocal, in recent years different studies reported how strength training could impact positively on endurance performance. The aim of this study was to evaluate the impact of a long-term strength coupled to endurance training protocol in comparison with endurance training protocol on cycling performance. 14 trained amateurs’ cyclists (males; 27,03 ± 3,75 years; 177,15 ± 5,69 cm; 69,67 ± 8,53 kg; 22,2 ± 1,67 BMI) that completed the Hero Dolomites 2018 competition and signed to the 2019 edition (86 km, 4500 m) participated to the study. 7 of them (treated) followed a 24 weeks strength training coupled to endurance training program to increase performance, the other (untreated) followed their endurance training routines without any specific resistance training protocol. FTP (Functional Threshold Power) test and 1RM (One Repetition Maximum) test (barbell squat and leg press 45°) were planned at week 1, week 8, week 16 and week 24. 2019 race times were compared to 2018 once. Treated individuals showed increased strength (barbell squat: +29,7 ± 7,8 kg; leg press 45°: +53,5 ± 13,1 kg) and FTP (+23,2 ± 9,3 W) from week 1 to week 24. Both treated and untreated individuals improved their race time from 2018 to 2019 (treated: -51,4 ± 24,6 m; untreated: -11,8 ± 14,4 m). Treated individuals improved significantly race time from 2018 compared to untreated individuals (p<0,05). Structured and periodized strength sessions can be incorporated and maintained for the entire duration of a 24 weeks training program impacting positively on endurance performance

    Everesting challenge attempt strategy: A case study

    Get PDF
    The Everesting challenge (repeat any hill, anywhere in the world, until you climb an altitude of 8848 m; the equivalent of M. Everest) is becoming an increasingly popular challenge. The physical and metabolic stress to which the body is exposed during this type of exercise is unusual and it is also particularly challenging for coaches, trainers and sport nutritionists. The aim of this study is to analyse the parameters and key details necessary to optimize a 10-week training protocol for an ultra-endurance performance like the Everesting challenge. An ex-élite cyclist, trained individual (male; 26 years; 181 cm; 71,7 kg; 21,9 BMI) followed a 10 weeks training and nutrition program to reach his peak performance and attempt the challenge. Body composition analysis checks (body weight, body circumferences, skinfold thickness and bioimpedance analysis) and performance tests (Conconi, Functional Threshold Power, Maximum Lactate Steady State) were planned at week 1, 5 and 10. After 10 weeks FTP increased from 245 to 267 W and at MLSS from 252 W to 270 W. Body weight decreased from 71,7 kg to 68,3 kg and body fat from 10,7% to 6,8 % (Jackson-Pollock 7 sites). The individual was able to accomplish the Everesting challenge concluding his ride in 13h34m27s, average power 162 W, average heart rate 139 bpm, 7685 kcal consumed. 10 weeks of strategically planned nutrition and training program may be sufficient to prepare an élite athlete or a well-trained individual to attempt an ultra-endurance challenge like the Everesting
    corecore