Simulation techniques have become a powerful tool for deciding the best starting conditions on pay-as-you-go scenarios. This is the case of public cloud infrastructures, where a given number and type of virtual machines (in short VMs) are instantiated during a specified time, being this reflected in the final budget. With this in mind, this paper introduces and validates iCanCloud, a novel simulator of cloud infrastruc-tures with remarkable features such as flexibility, scalability, performance and usability. Further-more, the iCanCloud simulator has been built on the following design principles: (1) it's targeted to conduct large experiments, as opposed to oth-ers simulators from literature; (2) it provides a flexible and fully customizable global hypervisor for integrating any cloud brokering policy; (3) it reproduces the instance types provided by a given cloud infrastructure; and finally, (4) it contains a user-friendly GUI for configuring and launching simulations, that goes from a single VM to large cloud computing systems composed of thousands of machines.Keywords Cloud computing · Cloud computing simulator · Cloud hypervisor · Validation · Scalability 1 to solve a given computational problem. If the same software and configurations are needed, the VMs may be started using the same image. This way, a machine offered by a computing cloud may become whatever the user needs, from a standalone computer to a cluster or Grid node.Nowadays, cloud computing systems are increasing their role due to the fast (r)evolution of computer networks and communication technologies. A very clear proof of this fact is that very important companies like Amazon, Google, Dell, IBM, and Microsoft are investing billions of dollars in order to provide their own cloud solutions [28].As soon as the scientific community had access to cloud production infrastructures, the first applications started to run on the cloud [26,34]. In many Research areas, the leap from traditional cluster and Grid computing to this new paradigm has been mandatory, being the main reason an evolution in the computational needs of the applications [10]. A remarkable fact from this evolution is that in a pre-cloud environment, hardware defines the level of parallelism of an application. In cloud computing, the level of parallelism is defined by the application itself, as there is no restriction in the number of machines, and CPU availability is 100% guaranteed by standard.There

A high incidence of thrombotic events, particularly deep vein thrombosis and pulmonary embolism, has been clearly documented in COVID-19 patients. In addition, small series of patients with coronary, cerebrovascular and peripheral arterial thrombotic events have also been reported, but their true incidence and consequences are not well described, and constitute the objective of this study. From February 1st to April 21st, 2020, 2115 COVID-19 patients were treated at Hospital Universitario Fundación Alcorcón (Madrid, Spain), and 1419 were eventually admitted. Patient characteristics and outcomes were collected by reviewing their electronic medical records. Fourteen patients had a systemic arterial thrombotic event, which represents a 1% incidence in relation to the total number of hospitalized patients. Three patients suffered an acute coronary syndrome, two with persistent ST-segment elevation, one of whom was treated invasively, and one with transient ST-segment elevation. Eight patients had a cerebrovascular event. Six suffered an acute ischemic stroke and two a transient ischemic attack, 50% of them had a Rankin score ≥ 3 at discharge. Three additional patients had a limb thrombotic event, all of them infrapopliteal, and were managed conservatively. All three cases developed necrosis of the toes, two of them with bilateral involvement. The hospitalization death rate of patients with an arterial event was 28.6%. Although COVID-19 may favor the occurrence of thrombotic events, the destabilization and thrombosis of arterial atherosclerotic plaques do not seem to be a frequent mechanism which warrants the need for specific systematic preventive measures. Keywords Thrombosis • Acute coronary syndrome • Stroke • Peripheral arterial disease • COVID-19 Highlights • Evidence of thrombosis is a common finding in severe COVID-19 patients. • There is very little data on the incidence and consequences of coronary, cerebrovascular and peripheral vascular thrombotic events. • In a large cohort of 1419 COVID-19 patients we observed a 1% incidence of systemic arterial thrombotic events, with a death rate of 28.6%. • Although SARS-CoV2 infection may favor arterial thrombotic events, with grave consequences, it does not seem to be a frequent enough phenomena to warrant the need for specific systematic preventive measures.

A high incidence of thrombotic events, particularly deep vein thrombosis and pulmonary embolism, has been clearly documented in COVID-19 patients. In addition, small series of patients with coronary, cerebrovascular and peripheral arterial thrombotic events have also been reported, but their true incidence and consequences are not well described, and constitute the objective of this study. From February 1st to April 21st, 2020, 2,115 COVID-19 patients were treated at Hospital Universitario Fundación Alcorcón (Madrid, Spain), and 1,419 were eventually admitted. Patient characteristics and outcomes were collected by reviewing their electronic medical records. Fourteen patients had a systemic arterial thrombotic event, which represents a 1% incidence in relation to the total number of hospitalized patients. Three patients suffered an acute coronary syndrome, two with persistent ST-segment elevation, one of whom was treated invasively, and one with transient ST-segment elevation. Eight patients had a cerebrovascular event. Six suffered an acute ischemic stroke and two a transient ischemic attack, 50% of them had a Rankin score ≥3 at discharge. Three additional patients had a limb thrombotic event, all of them infrapopliteal, and were managed conservatively. All three cases developed necrosis of the toes, two of them with bilateral involvement. The hospitalization death rate of patients with an arterial event was 28.6%. Although COVID-19 may favor the occurrence of thrombotic events, the destabilization and thrombosis of arterial atherosclerotic plaques do not seem to be a frequent mechanism which warrants the need for specific systematic preventive measures.

In this work, we propose new techniques to analyze the behavior, the performance, and specially the scalability of High Performance Computing (in short, HPC) applications on different computing architectures. Our final objective is to test applications using a wide range of architectures (real or merely designed) and scaling it to any number of nodes or components. This paper presents a new simulation framework, called SIMCAN, for HPC architectures. The main characteristic of the proposed simulation framework is the ability to be configured for simulating a wide range of possible architectures that involve any number of components. SIMCAN is developed to simulate complete HPC architectures, but putting special emphasis on the storage and network subsystems. The SIMCAN framework can handle complete components (nodes, racks, switches, routers, etc.), but also key elements of the storage and network subsystems (disks, caches, sockets, file systems, schedulers, etc.). We also propose several methods to implement the behavior of HPC applications. Each method has its own advantages and drawbacks. In order to evaluate the possibilities and the accuracy of the SIMCAN framework, we have tested it by executing a HPC application called BIPS3D on a hardware-based computing cluster and on a modeled environment that represent the real cluster. We also checked the scalability A. Núñez ( ) · New techniques for simulating high performance MPI 41 of the application using this kind of architecture by simulating the same application with an increased number of computing nodes.

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