CloudScope: diagnosing and managing performance interference in multi-tenant clouds

© 2015 IEEE.Virtual machine consolidation is attractive in cloud computing platforms for several reasons including reduced infrastructure costs, lower energy consumption and ease of management. However, the interference between co-resident workloads caused by virtualization can violate the service level objectives (SLOs) that the cloud platform guarantees. Existing solutions to minimize interference between virtual machines (VMs) are mostly based on comprehensive micro-benchmarks or online training which makes them computationally intensive. In this paper, we present CloudScope, a system for diagnosing interference for multi-tenant cloud systems in a lightweight way. CloudScope employs a discrete-time Markov Chain model for the online prediction of performance interference of co-resident VMs. It uses the results to optimally (re)assign VMs to physical machines and to optimize the hypervisor configuration, e.g. the CPU share it can use, for different workloads. We have implemented CloudScope on top of the Xen hypervisor and conducted experiments using a set of CPU, disk, and network intensive workloads and a real system (MapReduce). Our results show that CloudScope interference prediction achieves an average error of 9%. The interference-aware scheduler improves VM performance by up to 10% compared to the default scheduler. In addition, the hypervisor reconfiguration can improve network throughput by up to 30%

Promoting Adherence to Influenza Vaccination Recommendations in Pediatric Practice.

OBJECTIVES: In the United States, nonadherence to seasonal influenza vaccination guidelines for children and adolescents is common and results in unnecessary morbidity and mortality. We conducted a quality improvement project to improve vaccination rates and test effects of 2 interventions on vaccination guidelines adherence. METHODS: We conducted a cluster randomized control trial with 11 primary care practices (PRACTICE) that provided care for 11 293 individual children and adolescents in a children\u27s health care system from September 2015 through April 2016. Practice sites (with their clinicians) were randomly assigned to 4 arms (no intervention [Control], computerized clinical decision support system [CCDSS], web-based training [WBT], or CCDSS and WBT [BOTH]). RESULTS: During the study, 55.8% of children and adolescents received influenza vaccination, which improved modestly during the study period compared with the prior influenza season ( P = .009). Actual adherence to recommendations, including dosing, timeliness, and avoidance of missed opportunities, was 46.4% of patients cared for by the PRACTICE. The WBT was most effective in promoting adherence with vaccination recommendations with an estimated average odds ratio = 1.26, P \u3c .05, to compare between preintervention and intervention periods. Over the influenza season, there was a significantly increasing trend in odds ratio in the WBT arm ( P \u3c .05). Encouraging process improvements and providing longitudinal feedback on monthly rate of vaccination sparked some practice changes but limited impact on outcomes. CONCLUSIONS: Web-based training at the start of influenza season with monthly reports of adherence can improve correct dose and timing of influenza vaccination with modest impact on overall vaccination rate

Resonant Transport in Nb/GaAs/AlGaAs/GaAs Microstructures

Resonant transport in a hybrid semiconductor-superconductor microstructure grown by MBE on GaAs is presented. This structure experimentally realizes the prototype system originally proposed by de Gennes and Saint-James in 1963 in \emph{all}-metal structures. A low temperature single peak superimposed to the characteristic Andreev-dominated subgap conductance represents the mark of such resonant behavior. Random matrix theory of quantum transport was employed in order to analyze the observed magnetotransport properties and ballistic effects were included by directly solving the Bogoliubov-de Gennes equations.Comment: 7 pages REVTeX, 4 figures, to be published by World Scientific in Proceedings of International Symposium on Mesoscopic Superconductivity and Spintronics (NTT R&D Center Atsugi, Japan, March 2002

Comparative Analysis of Sliding Resistance of Different Lingual Systems

Objective: To analyse and compare the frictional properties of 4 lingual systems combined with two types of stainless steel archwire (0.016x0.022, 0.018x0.025) and a 0.018x0.025 TMA archwire by simulating different misalignment situations in vitro. Material and Methods: Five randomly chosen brackets from each system (e-Brace, Harmony, Incognito, and STb) were used for the measurements and to simulate an upper first premolar extraction case. The friction tests were performed using a material testing machine in combination with a specialized test rig. Results: The lowest absolute friction values were found with the 0.016x0.022 SS wire in a passive configuration. STb provided the lowest mean friction, while Harmony brackets displayed the highest friction. The TMA Beta Titanium wire showed the highest friction values, but maintained proportions similar to those of the other wires as tip and torsion increased. Conclusion: The type of bracket has a significant impact on friction, and there is a positive correlation between mesiodistal bracket width and resistance to sliding. The archwire sections and materials and the vertical displacement, also significantly affect the friction generated by the system

Conventional MRI-Derived Biomarkers of Adult-Type Diffuse Glioma Molecular Subtypes: A Comprehensive Review

The introduction of molecular criteria into the classification of diffuse gliomas has added interesting practical implications to glioma management. This has created a new clinical need for correlating imaging characteristics with glioma genotypes, also known as radiogenomics or imaging genomics. Although many studies have primarily focused on the use of advanced magnetic resonance imaging (MRI) techniques for radiogenomics purposes, conventional MRI sequences remain the reference point in the study and characterization of brain tumors. A summary of the conventional imaging features of glioma molecular subtypes should be useful as a tool for daily diagnostic brain tumor management. Hence, this article aims to summarize the conventional MRI features of glioma molecular subtypes in light of the recent literature

Mesoscopic Analysis of Structure and Strength of Dislocation Junctions in FCC Metals

We develop a finite element based dislocation dynamics model to simulate the structure and strength of dislocation junctions in FCC crystals. The model is based on anisotropic elasticity theory supplemented by the explicit inclusion of the separation of perfect dislocations into partial dislocations bounding a stacking fault. We demonstrate that the model reproduces in precise detail the structure of the Lomer-Cottrell lock already obtained from atomistic simulations. In light of this success, we also examine the strength of junctions culminating in a stress-strength diagram which is the locus of points in stress space corresponding to dissolution of the junction.Comment: 9 Pages + 4 Figure

Structure and Strength of Dislocation Junctions: An Atomic Level Analysis

The quasicontinuum method is used to simulate three-dimensional Lomer-Cottrell junctions both in the absence and in the presence of an applied stress. The simulations show that this type of junction is destroyed by an unzipping mechanism in which the dislocations that form the junction are gradually pulled apart along the junction segment. The calculated critical stress needed for breaking the junction is comparable to that predicted by line tension models. The simulations also demonstrate a strong influence of the initial dislocation line directions on the breaking mechanism, an effect that is neglected in the macroscopic treatment of the hardening effect of junctions.Comment: 4 pages, 3 figure

STAT6 variants associate with relapse of fosinophilic esophagitis in patients receiving long-term proton pump inhibitor therapy

Background & Aims: Based on histologic features, variants in STAT6 are associated with a poor initial response to proton pump inhibitor (PPI) therapy in pediatric patients with eosinophilic esophagitis (EoE). We investigated whether these genetic variants are associated with a poor long-term response in children with EoE who initially responded to PPI therapy. Methods: We performed a prospective longitudinal cohort study of children ages 2 to 16 years who met the diagnostic criteria for EoE (≥15 eosinophils/high-power field [eos/hpf]), responded to 8 weeks of treatment with 2 mg/kg/d PPI (<15 eos/hpf), and whose dose then was reduced to 1 mg/kg/d PPI (maintenance therapy) for 1 year, at which point biopsy specimens were collected by endoscopy. Genomic DNA was isolated from formalin-fixed paraffin-embedded biopsy tissue and was genotyped for variants of STAT6. Remission of inflammation was assessed at eos/hpf thresholds of <15 and ≤5. Results: Among 73 patients who received 1 mg/kg/d PPI maintenance therapy for 1 year, 13 patients (18%) had 6 to 14 eos/hpf, 36 patients (49%) had 5 or fewer eos/hpf, and 24 patients (33%) relapsed to EoE (≥15 eos/hpf). Carriage of any of 3 STAT6 variants in linkage disequilibrium (r2 ≥0.8; rs324011, rs167769, or rs12368672) was associated with a 2.3- to 2.8-fold increase in the odds of EoE relapse, and with a 2.8- to 4.1-fold increase in the odds of having 6 to 14 eos/hpf. For rs324011, the odds ratio [95% CI] for relapse was 2.77 [1.11, 6.92]; P = .029, and the odds ratio [95% CI] for having 6 to 14 eos/hpf was 3.06 [1.27, 7.36]; P = .012. Conclusions: Pediatric EoE patients who initially respond to PPI therapy and carry STAT6 variants rs324011, rs167769, or rs12368672 are at increased risk of relapse after 1 year of PPI maintenance therapy

Newly Developed and Validated Eosinophilic Esophagitis Histology Scoring System and Evidence that it Outperforms Peak Eosinophil Count for Disease Diagnosis and Monitoring

Eosinophilic esophagitis is diagnosed by symptoms, and at least 15 intraepithelial eosinophils per high power field in an esophageal biopsy. Other pathologic features have not been emphasized. We developed a histology scoring system for esophageal biopsies that evaluates eight features: eosinophil density, basal zone hyperplasia, eosinophil abscesses, eosinophil surface layering, dilated intercellular spaces, surface epithelial alteration, dyskeratotic epithelial cells and lamina propria fibrosis. Severity (grade) and extent (stage) of abnormalities were scored using a 4 point scale (0 normal; 3 maximum change). Reliability was demonstrated by strong to moderate agreement among 3 pathologists who scored biopsies independently (p≤0.008). Several features were often abnormal in 201 biopsies (101 distal, 100 proximal) from 104 subjects (34 untreated, 167 treated). Median grade and stage scores were significantly higher in untreated compared to treated subjects (p≤0.0062). Grade scores for features independent of eosinophil counts were significantly higher in biopsies from untreated compared to treated subjects (basal zone hyperplasia p≤0.024 and dilated intercellular spaces p≤0.005), and were strongly correlated (r-square\u3e0.67). Principal components analysis identified 3 principal components that explained 78.2% of the variation in the features. In logistic regression models, 2 principal components more closely associated with treatment status than log distal peak eosinophil count (r-square 17, area under the curve 77.8 vs r-square 9, area under the curve 69.8). In summary, the eosinophilic esophagitis histology scoring system provides a method to objectively assess histologic changes in the esophagus beyond eosinophil number. Importantly, it discriminates treated from untreated patients, uses features commonly found in such biopsies, and is utilizable by pathologists after minimal training. These data provide rationales and a method to evaluate esophageal biopsies for features in addition to peak eosinophil count