Scalable Traffic-Aware Virtual Machine Management for Cloud Data Centers

Virtual Machine (VM) management is a powerful mechanism for providing elastic services over Cloud Data Centers (DC)s. At the same time, the resulting network congestion has been repeatedly reported as the main bottleneck in DCs, even when the overall resource utilization of the infrastructure remains low. However, most current VM management strategies are traffic-agnostic, while the few that are traffic-aware only concern a static initial allocation, ignore bandwidth oversubscription, or do not scale. In this paper we present S-CORE, a scalable VM migration algorithm to dynamically reallocate VMs to servers while minimizing the overall communication footprint of active traffic flows. We formulate the aggregate VM communication as an optimization problem and we then define a novel distributed migration scheme that iteratively adapts to dynamic traffic changes. Through extensive simulation and implementation results, we show that S-CORE achieves significant (up to 87%) communication cost reduction while incurring minimal overhead and downtime. Index Terms—Virtual Machine, Migration, Consolidation, Communication Cost, Scalable, Traffic-Aware, Data Center Networ

Variation of leaf litter decomposition among rivers, lagoons and sea: an experiment from Corfu island (Greece)

In aquatic ecosystems, the decomposition of organic detritus represents one of the most important ecosystem functions, which support complex detritus-based food webs that determine the critical balance between carbon mineralization and sequestration. The performance of the decomposition process is usually expressed as rate of decomposition, being a synthetic measure that take into account both abiotic and biotic factors. Decomposition rates have been also applied to evaluate the ecological status in terms of ecological functionality. However, despite a growing number of studies have tested the rate of decomposition between leaves of different riparian tree species in different aquatic ecosystems including rivers, transitional waters and sea, no comparative study among ecosystems typology is available up to date. Here, we compare decomposition rates from rivers, lagoons and sea of Corfu island (Greece). Five sampling sites were fixed in each of the three of the most important rivers and lagoons; other five sampling sites were fixed in the sea around the island. Twelve leaf packs containing 3±0.005 g of oven-dried Phragmites australis leaves were submerged in April 2014 and retrieved in May 2014 (after 30 days). Abiotic parameters were recorded in both sampling times. The retrieved leaf packs were cleaned and the macroinvertebrates retained were removed, counted, identified at lower taxonomic level and weighted. Leaf pack decomposition rates were calculated, and their variability was compared within each aquatic ecosystem, within each ecosystem typology (river, lagoon, sea) and among ecosystem typology. The results are going to be presented on the poster

Effect of sealants on laser fluorescence caries detection in primary teeth

The aim of this study was to investigate in vitro the effects of clear or opaque sealants, on the laser fluorescence readings for occlusal caries detection in primary molars, For this reason, 427 occlusal sites in 199 teeth were clinically examined by one dentist, and their laser fluorescence (LF) was measured locally with the DIAGNOdent™ device, both before and after the teeth had been sealed with Delton Clear LC or Delton Opaque LC, For 29 of these teeth, we also measured the laser fluorescence by scanning the fissures before and after sealant application, We used Wilcoxon's signed ranks sum test and Spearman's rho correlation to compare and correlate the LF readings before and after sealing, while we used the Mann-Whitney U test to compare the two materials, Finally, we used the Kruskal-Wallis test to compare readings taken locally with those taken by the scanning technique, The results showed that there was an LF increase by a mean of 6 units after sealing with the clear material, while there was a 15 units decrease after sealing with the opaque one, LF readings before and after sealing correlated better for the clear material (rho= 0.826) than for the opaque one (rho=0.507), LF readings were statistically significantly affected by both clear and opaque sealants (P<0.001), However, this effect was statistically significantly less pronounced for the clear material (P<0.001), There was also no difference between the LF readings taken by the fissure scanning technique or locally (P>0.05), In conclusion, LF readings for occlusal caries detection in primary molars were significantly affected by both the clear and the opaque materials, However, the effect for the opaque material was more pronounced. © Springer-Verlag London Ltd 2010

In vivo validation of Diagnodent and Vista proof devices vs ICDAS clinical criteria on incipient carious lesions in adults

Aim: This study aimed to validate the in vivo performance of Diagnodent and Vista proof devices with ICDAS clinical criteria on incipient carious lesions in adults. Methods: A total of 44 adult patients with 230 incipient occlusal caries took part in the present study. These patients were assessed for caries with ICDAS clinical criteria, and then they were examined with Diagnodent pen™ (DP) and Vista proof™ (VP) fluorescence devices. Sensitivity, specificity accuracy, and ICC agreement between devices with ICDAS criteria, which served as a gold standard, were evaluated. Results: Regarding the caries diagnostic devices, sensitivity and specificity found 0,61 and 0,51 for DP, and 0,64 and 0,54 for VP, respectively. The different detection methods showed no differences in diagnostic capacity (Az values) each other, and ICC values with ICDAS criteria were calculated low. Conclusions: DP and VP do not contribute to incipient occlusal carious lesions' better detective ability compared with visual ICDAS clinical criteria. The DP and VP devices presented no differences in diagnostic ability and measured lesion depth concerning the visual examination. © 2021 Elsevier B.V

Validation of different Cariogram settings and factor combinations in preschool children from areas with high caries risk

Background: Caries risk assessment in preschool children has been limited validated. Aim: To validate caries predictive ability of Cariogram using different combinations of factors and settings in preschool children from areas with high caries risk. Design: Two to five years old children (N = 175) were examined for caries (cavitated and non-cavitated lesions), at baseline and after 1 and 2 years. Mutans streptococci counts (MS) and saliva buffer capacity (SBC) were measured with chair side tests. Diet and oral health attitude were assessed through a parental questionnaire. Baseline caries risk was calculated using standard and high-risk group variables in Cariogram either with nine factors or excluding MS and SBC. Poisson regression models, ROC analysis and information criteria (AIC and BIC), P < 0.05, were used to investigate the predictive ability of Cariograms and to quantify the associations. Results: Accuracy of Cariogram was found limited. Cariograms with MS showed higher sensitivity but lower specificity than those without bacterial counts. Standard set Cariograms with MS counts performed slightly better than the other models, but the difference was not statistically significant. Caries prediction with standard and high set Cariograms was also found limited. Conclusions: Cariogram with various factors and settings displayed suboptimal ability to predict caries in this population. © 2019 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Lt

Caries risk assessment with the ‘Bangkok checklist’ in preschool children: A prospective cohort study

Background: Caries risk assessment in preschool children is poorly validated in prospective studies. Aim: To validate the Bangkok checklist (BCL) in predicting caries development in a cohort of preschool children from low and moderate socioeconomic areas and compare it with two established risk assessment tools. Design: We followed 146 preschool children, aged 2-5 years for 2 years. At baseline, the caries risk category (low, moderate, high) was determined with three checklists: (a) BCL, (b) American Academy of Pediatric Dentistry form (CRAF), and (c) Caries Management By Risk Assessment (CAMBRA). Data were collected from questionnaires and clinical examinations. Caries increment was recorded by counting the number of surfaces that changed from sound to decayed. We used Kendall's tau, Poisson regression models and ROC analysis to assess the predictive ability of the different checklists. Results: Over 50% of the children developed new caries on a yearly basis. The BCL assigned the majority of the children (87%) into the high-risk category. Sensitivity was 88% but specificity was low (16%). Accuracy of BCL was similar to CRAF but inferior to CAMBRA. Conclusions: Bangkok checklist had a very limited performance in accurately predicting future early childhood caries in this population. © 2021 BSPD, IAPD and John Wiley & Sons Lt

Gingival fibromatosis and significant tooth eruption delay in an 11-year-old male: A 30-month follow-up

This case report describes the dental management of an unusual case of idiopathic gingival fibromatosis with multiple impacted primary teeth, and the absence of eruption of permanent teeth, in an 11-year-old boy and at the 30-month follow-up. The patient presented with severely enlarged gingival tissues affecting both arches and multiple retained and nonerupted primary teeth. He had already been subjected to localized gingivectomies at the ages of 7 and 9 years. He had no known syndrome and there was no family history of any similar disorder. The patient was treated under general anaesthesia to remove the excessive gingival tissues using apically positioned flaps. During the surgical procedure, over-retained and unerupted impacted primary teeth were extracted in order to facilitate the eruption of the permanent successors. Two years post-operatively, there was no recurrence of the gingival enlargement. Overdentures were then constructed because none of the permanent teeth had yet erupted. Furthermore, preeruptive coronal resorption was detected radiographically affecting the crown of the unerupted 36. Thirty months postoperatively, no recurrence of gingival enlargement was seen, but the permanent teeth had still not erupted. © 2005 BSPD and IAPD

The two most serious problems in the educational environment of greek medical schools, identified by 803 students, could readily be solved

OBJECTIVE Medical students are influenced by their educational environment (EE) in ways that can facilitate or impede their learning. This study aimed to measure the quality of the EE of the Greek medical schools. METHOD The Dundee Ready Educational Environment Measure (DREEM) questionnaire, an internationally recognized tool for the measurement of the perceptions of students about the EE of their schools, translated into Greek, was disseminated electronically to the students of all years, of all the medical schools in the country. It consists of 50 questions covering various aspects of EE, grouped into 5 categories, “learning”, “teachers”, “academic performance”, “atmosphere”, “social life”. For each question, category and total sum the average score was calculated and interpreted as follows: 0–24.9% very poor EE, 25–39.9% poor, 40–49.9% fairly poor, 50–59.9% fairly positive, 60–74.9% positive, 75–100% very positive. RESULTS A total of 803 students (330 male, 468 female) responded, with representation of all the schools (specifically, Thessaloniki 179, Ioannina 157, Athens 100, Thessaly 95, Patras 92, Crete 91, Thrace 89) and of all years of study (first 170, second 121, third 144, fourth 125, fifth 109, sixth 94, after sixth 40), although the sample was not statistically representative. The overall score was 51%, with the sub-scores: “Teachers” 54%, “academic performance” 54%, “social life” 53%, “atmosphere” 52%, “learning” 45%. Particularly negative aspects were: Teachers informing students about their progress (15%), support for students who are stressed (21%), boredom in class (33%), emphasis on memorizing rather than critical thinking (34%), ability of students to memorize everything needed (39%). Particularly good aspects were: Pleasant accommodation (77%), good friends (76%), teachers knowledgeable in their disciplines (72%), good social life (70%), conviction that this time they will pass their exams (68%), feeling socially comfortable in class (67%), not finding the whole experience disappointing (66%). CONCLUSIONS Greek medical students perceive the EE of their schools at the cut-off point between poor and good, with serious problems to be addressed. Their attitude towards learning in particular is below the limit (4.5). Particularly positive aspects were identified in the extracurricular aspects of the EE, and particularly negative aspects in the curriculum and learning, where it is apparent that effective evidencebased measures are needed. The two worst aspects could be readily improved. Systematic annual measurement of the EE quality would provide the necessary data for implementing evidence-based educational policy. © Athens Medical Society