12 research outputs found
Cooling Systems in Data Centers: State of Art and Emerging Technologies
No full textThe growing number, size, complexity and energy density of data centers due to increasing demand for storage, networking and computation bring a considerable energy challenge. Several measures to improve energy efficiency are being studied, not only to allow a supportable industry growth but also to reduce operational costs. Cooling energy consumption constitutes a large portion of the total consumption of data centers, which can account up to 40% in the case of inefficient cooling systems. In this paper a critical discussion on existing and emerging technologies for data center cooling systems was carried out. Fundamental aspects concerning advantages and drawbacks of each examined cooling system were discussed. Moreover a critical analysis on next future technology solutions for obtaining high energy efficiency data center is performed
Per un effettivo contrasto alla violenza di genere e domestica: tra istanze repressive e prospettive riparative.
No full textDopo aver evidenziato le criticità degli interventi in materia penalistica in tema di violenza di genere e
domestica, l’Autrice si sofferma sulle potenzialità offerte dal paradigma riparativo in tale contesto, anche alla
luce delle novità introdotte dalla Riforma Cartabia. Il contributo si conclude con delle riflessioni sugli
interventi legislativi necessari, anche in prospettiva de iure condendo, per assicurare effettività di tutela per
le vittime.
The author analyzes the critical points of the criminal intervention on gender-based and domestic violence
and considers the potential application offered by the restorative paradigm in this context, also in the light of
the innovations introduced by the “Cartabia Reform”. The paper concludes with some reflections about the
necessary interventions on this subject to ensure the effectiveness of victims protection, also in a de iure
condendo perspective
Bladder cancer: do we need contrast injection for MRI assessment of muscle invasion? A prospective multi-reader VI-RADS approach
No full textObjectives: (1) To investigate whether a contrast-free biparametric MRI (bp-MRI) including T2-weighted images (T2W) and diffusion-weighted images (DWI) can be considered an accurate alternative to the standard multiparametric MRI (mp-MRI), consisting of T2, DWI, and dynamic contrast-enhanced (DCE) imaging for the muscle-invasiveness assessment of bladder cancer (BC), and (2) to evaluate how the diagnostic performance of differently experienced readers is affected according to the type of MRI protocol. Methods: Thirty-eight patients who underwent a clinically indicated bladder mp-MRI on a 3-T scanner were prospectively enrolled. Trans-urethral resection of bladder was the gold standard. Two sets of images, set 1 (bp-MRI) and set 2 (mp-MRI), were independently reviewed by four readers. Descriptive statistics, including sensitivity and specificity, were calculated for each reader. Receiver operating characteristic (ROC) analysis was performed, and the areas under the curve (AUCs) were calculated for the bp-MRI and the standard mp-MRI. Pairwise comparison of the ROC curves was performed. Results: The AUCs for bp- and mp-MRI were respectively 0.91–0.92 (reader 1), 0.90 (reader 2), 0.95–0.90 (reader 3), and 0.90–0.87 (reader 4). Sensitivity was 100% for both protocols and specificity ranged between 79.31 and 89.66% and between 79.31 and 83.33% for bp-MRI and mp-MRI, respectively. No significant differences were shown between the two MRI protocols (p > 0.05). No significant differences were shown accordingly to the reader’s experience (p > 0.05). Conclusions: A bp-MRI protocol consisting of T2W and DWI has comparable diagnostic accuracy to the standard mp-MRI protocol for the detection of muscle-invasive bladder cancer. The experience of the reader does not significantly affect the diagnostic performance using VI-RADS. Key Points: • The contrast-free MRI protocol shows a comparable accuracy to the standard multiparametric MRI protocol in the bladder cancer muscle-invasiveness assessment. • VI-RADS classification helps non-expert radiologists to assess the muscle-invasiveness of bladder cancer. • DCE should be carefully interpreted by less experienced readers due to inflammatory changes representing a potential pitfall. © 2020, The Author(s)
Conspicuity and muscle-invasiveness assessment for bladder cancer using VI-RADS: a multi-reader, contrast-free MRI study to determine optimal b-values for diffusion-weighted imaging
No full textOBJECTIVE: To (1) compare bladder cancer (BC) muscle invasiveness among three b-values using a contrast-free approach based on Vesical Imaging-Reporting and Data System (VI-RADS), to (2) determine if muscle-invasiveness assessment is affected by the reader experience, and to (3) compare BC conspicuity among three b-values, qualitatively and quantitatively. METHODS: Thirty-eight patients who underwent a bladder MRI on a 3.0-T scanner were enrolled. The gold standard was histopathology report following transurethral resection of BC. Three sets of images, including T2w and different b-values for DWI, set 1 (b = 1000 s/mm(2)), set 2 (b = 1500 s/mm(2)), and set 3 (b = 2000 s/mm(2)), were reviewed by three differently experienced readers. Descriptive statistics and Intraclass Correlation Coefficient (ICC) were calculated. Comparisons among readers and DWI sets were performed with the Wilcoxon test. Receiver operating characteristic (ROC) analysis was performed. Areas under the curves (AUCs) and pairwise comparison were calculated. RESULTS: AUCs of muscle-invasiveness assessment ranged from 0.896 to 0.984 (reader 1), 0.952–0.968 (reader 2), and 0.952–0.984 (reader 3) without significant differences among different sets and readers (p > 0.05). The mean conspicuity qualitative scores were higher in Set 1 (2.21–2.33), followed by Set 2 (2–2.16) and Set 3 (1.82–2.14). The quantitative conspicuity assessment showed that mean normalized intensity of tumor was significantly higher in Set 2 (4.217–4.737) than in Set 1 (3.923–4.492) and Set 3 (3.833–3.992) (p < 0.05). CONCLUSION: Muscle invasiveness can be assessed with high accuracy using a contrast-free protocol with T2W and DWI, regardless of reader’s experience. b = 1500 s/mm(2) showed the best tumor delineation, while b = 1000 s/mm(2) allowed for better tumor–wall interface assessment
Essays in Nonlinear Econometrics
No full textIn this dissertation, I study standard models, but investigate the necessity of (possibly large) deviations from basic assumptions. In Chapter 1, my co-author Ross Askanazi and I revisit the use of factor models in finance. Historical literature on the subject decomposes volatility into a factor component (systemic risk) and a remainder (idiosyncratic risk). Recent work has suggested that a market shock to volatility may increase both systemic risk and idiosyncratic risk — specifically, that idiosyncratic volatility of US equities data has a factor structure, with the factor highly correlated with, and possibly precisely the market volatility. In this paper we attempt to characterize the underlying factor and find that it can be decomposed into a statistical (PCA) and structural (market volatility) factor. We also show that this feature is more common than expected, appearing in diverse sets of financial data. Lastly, we find that this dual-factor approach is slightly dominated in forecasting environments by a single statistical factor. In Chapter 2 I revisit the classical Vector Autoregression (VAR) model, but allow parameters to time-vary. Time-Varying parameter models have be- come more popular in recent years, especially as they are adapted to accommodate larger datasets. However, all recent developments use standard priors, specifically the Inverse-Wishart class of priors over the parameter error covariance matrix. In this paper, I show that Inverse-Wishart priors have a number of negative properties, and that those properties are salient in a TVP context since there is little information from the likelihood. Fully aware of these deficiencies, the Bayesian Random Effects literature has developed a series of uninformative priors to correct these weaknesses. In this paper, I adapt one of those priors into an informative and easily understandable prior for covariances. I show that the new prior effects posterior inference and displays improved frequentist properties. I apply my prior to the canonical Primiceri (2005) dataset and find that their results were sensitive to the choice of prior. I further apply the prior to two forecasting exercises and find that while it improves forecasts for the Primiceri data, it does not for an alternative (larger) dataset
Patients' perceptions of quality of care delivery by urology residents: A nationwide study
No full textPatients' perceptions of quality of care delivery by urology residents: A nationwide study
No full textOBJECTIVE: To present the results of a nationwide survey among urological patients to evaluate their perception of the quality of care provided by residents. METHODS: An anonymous survey was distributed to patients who were referred to 22 Italian academic institutions. The survey aimed to investigate the professional figure of the urology resident as perceived by the patient. RESULTS: A total of 2587 patients were enrolled in this study. In all, 51.6% of patients were able to correctly identify a urology resident; however, almost 40% of respondents discriminated residents from fully trained urologists based exclusively on their young age. Overall, 98.2% patients rated the service provided by the resident as at least sufficient. Urology trainees were considered by more than 50% of the patients interviewed to have good communication skills, expertise and willingness. Overall, patients showed an excellent willingness to be managed by urology residents. The percentage of patients not available for this purpose showed an increasing trend that directly correlated with the difficulty of the procedure. Approximately 5–10% of patients were not willing to be managed by residents for simple procedures such as clinical visits, cystoscopy or sonography, and up to a third of patients were not prepared to undergo any surgical procedure performed by residents during steps in major surgery, even if the residents were adequately tutored. CONCLUSIONS: Our data showed that patients have a good willingness to be managed by residents during their training, especially for medium‐ to low‐difficulty procedures. Furthermore, the majority of patients interviewed rated the residents' care delivery as sufficient. Urology trainees were considered to have good communication skills, expertise and willingness
The Properties of Survey-Based Inflation Expectations in Sweden
No full textThis paper assesses the properties of survey-based inflation expectations in Sweden. The survey is conducted by Prospera once every quarter and consists of respondents from businesses and labour-market organisa-tions. The paper shows that inflation expectations measured in this sur-vey tend to be biased and inefficient forecasts of future inflation. Results also indicate that long-run inflation expectations are overly adaptive with respect to actual inflation. Finally, evaluations of forecast accuracy show that these inflation expectations are worse predictors of inflation than those of a professional forecasting institution and also typically outper-formed by a simple autoregressive model. Overall, our results indicate that economic agents’ expectations formation process is suboptimal and/or the survey fails to capture the true inflation expectations.Survey data; Inflation targeting
Explaining Output Volatility: The Case of Taxation
No full textThis paper presents empirical evidence against the popular perception that macro volatility is exogenous. We obtain tax effects on macro aggregates in the stochastic neoclassical model. Taxes are shown to affect the second moment of output growth rates without affecting the first moment. Exploiting heterogeneity patterns in a panel of OECD countries, we estimate tax effects on macro volatility, explicitly modeling the unobserved variance process. We find a strong empirical link between taxes and output volatility. Accounting for non-stationarity of taxes and output volatility, we find empirical evidence of a cointegrating relationship.macroeconomic volatility, tax effects, continuous-time DSGE models
