On the Benefit of Virtualization: Strategies for Flexible Server Allocation

Virtualization technology facilitates a dynamic, demand-driven allocation and migration of servers. This paper studies how the flexibility offered by network virtualization can be used to improve Quality-of-Service parameters such as latency, while taking into account allocation costs. A generic use case is considered where both the overall demand issued for a certain service (for example, an SAP application in the cloud, or a gaming application) as well as the origins of the requests change over time (e.g., due to time zone effects or due to user mobility), and we present online and optimal offline strategies to compute the number and location of the servers implementing this service. These algorithms also allow us to study the fundamental benefits of dynamic resource allocation compared to static systems. Our simulation results confirm our expectations that the gain of flexible server allocation is particularly high in scenarios with moderate dynamics

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

ProActive routing in scalable data centers with PARIS

Modern data centers must scale to a large number of servers, while offering flexible placement and migration of virtual machines. The traditional approach of connecting layer-two pods through a layer-three core constrains VM placement. More recent 'flat' designs are more flexible but have scalability limitations due to flooding/broadcasting or querying directories of VM locations. Rather than reactively learn VM locations, our PARIS architecture has a controller that pre-positions IP forwarding entries in the switches. Switches within a pod have complete information about the VMs beneath them, while each core switch maintains complete forwarding state for part of the address space. PARIS offers network designers the flexibility to choose a topology that meets their latency and bandwidth requirements. We evaluate our PARIS prototype built using OpenFlow-compliant switches and NOX controller. Using PARIS we can build a data center network that supports up to 100K servers

Intrathecal Tramadol for prevention of shivering in Anorectal surgeries under Sub arachnoid anaesthesia

Introduction: Shivering is very common problem during Sub arachnoid block (SAB), also known as Spinal anaesthesia. It can be prevented by intrathecal opioid injection. Material and method: In our study we have included 50 patients scheduled for anorectal surgery. They all were given spinal anaesthesia with bupivacaine 12.5 mg along with injection Tramadol 10 mg and watched for initial 4 hour. Result: 3 out of 50 patients showed shivering in treatment group who have received injection Tramadol. Discussion: Probable mechanism of action is its activity at mu receptor and serotonin and nor epinephrine reuptake inhibition Conclusion: Intrathecal Tramadol in dose of 10 mg prevents shivering in most of the patients. It can safely be used for prevention of shivering without significant side effect

Comics An Introduction

Earle also pushes beyond the book to lay out the ways that fans engage with their comics of choice – and how this can impact the industry. She also analyses how Comics can work for social change and political comment

Rapid strengthening of reinforced concrete bridges

167 p.An innovative technique for repairing reinforced concrete beams (or slabs) by attaching FRP (fiber reinforced polymer) strengthening strips to the underside of the beam using powder actuated fasteners and mechanical anchors was developed at the University of Wisconsin-Madison under funding from the U.S. Army Corps of Engineers. The method is known as the Mechanically Fastened (MF) Fiber-Reinforced Polymer (MF-FRP) method, to distinguish it from the traditional Externally-Bonded FRP (EB-FRP) method. This method is rapid and uses simple hand tools, lightweight materials, and unskilled labor. Unlike the conventional method of adhesively bonding FRP strips to the concrete surface, this method does not require much surface preparation and allows for immediate use of the strengthened structure. The potential to use the method as a rapid and temporary means of upgrading load-capacity deficient bridges in the State was studied. Such an option is desirable to local governments that have budget constraints and need to replace many older deficient bridges. In this research, the MF-FRP method was used to strengthen a bridge in Edgerton, Wisconsin, which was subsequently tested to failure. Additional laboratory tests on strengthened beams were conducted at the University of Wisconsin-Madison. The major finding of this research was that the MF-FRP method could be used to strengthen an existing deteriorated bridge. The Inventory Rating of the bridge strengthened was increased from an HS17 rating to HS25 rating for a unit cost of materials and manpower of approximately $12 per sq ft. The method is easy to use in the field and the level of strengthening can be predicted in advance using conventional analytical methods