Discrete sine transform for multi-scale realized volatility measures

In this study we present a new realized volatility estimator based on a combination of the multi-scale regression and discrete sine transform (DST) approaches. Multi-scale estimators similar to that recently proposed by Zhang (2006) can, in fact, be constructed within a simple regression-based approach by exploiting the linear relation existing between the market microstructure bias and the realized volatilities computed at different frequencies. We show how such a powerful multi-scale regression approach can also be applied in the context of the Zhou [Nonlinear Modelling of High Frequency Financial Time Series, pp. 109–123, 1998] or DST orthogonalization of the observed tick-by-tick returns. Providing a natural orthonormal basis decomposition of observed returns, the DST permits the optimal disentanglement of the volatility signal of the underlying price process from the market microstructure noise. The robustness of the DST approach with respect to the more general dependent structure of the microstructure noise is also shown analytically. The combination of the multi-scale regression approach with DST gives a multi-scale DST realized volatility estimator similar in efficiency to the optimal Cramer–Rao bounds and robust against a wide class of noise contamination and model misspecification. Monte Carlo simulations based on realistic models for price dynamics and market microstructure effects show the superiority of DST estimators over alternative volatility proxies for a wide range of noise-to-signal ratios and different types of noise contamination. Empirical analysis based on six years of tick-by-tick data for the S&P 500 index future, FIB 30, and 30 year U.S. Treasury Bond future confirms the accuracy and robustness of DST estimators for different types of real data

Characterization of the demonstrator of the fast silicon monolithic ASIC for the TT-PET project

The TT-PET collaboration is developing a small animal TOF-PET scanner based on monolithic silicon pixel sensors in SiGe BiCMOS technology. The demonstrator chip, a small-scale version of the final detector ASIC, consists of a 3 x 10 pixel matrix integrated with the front-end, a 50 ps binning TDC and read out logic. The chip, thinned down to 100 {\mu}m and backside metallized, was operated at a voltage of 180 V. The tests on a beam line of minimum ionizing particles show a detection efficiency greater than 99.9 % and a time resolution down to 110 ps

Sensitivity of imaging for multifocal-multicentric breast carcinoma

<p>Abstract</p> <p>Background</p> <p>This retrospective study aims to determine: 1) the sensitivity of preoperative mammography (Mx) and ultrasound (US), and re-reviewed Mx to detect multifocal multicentric breast carcinoma (MMBC), defined by pathology on surgical specimens, and 2) to analyze the characteristics of both detected and undetected foci on Mx and US.</p> <p>Methods</p> <p>Three experienced breast radiologists re-reviewed, independently, digital mammography of 97 women with MMBC pathologically diagnosed on surgical specimens. The radiologists were informed of all neoplastic foci, and blinded to the original mammograms and US reports. With regards to Mx, they considered the breast density, number of foci, the Mx characteristics of the lesions and their BI-RADS classification. For US, they considered size of the lesions, BI-RADS classification and US pattern and lesion characteristics. According to the histological size, the lesions were classified as: index cancer, 2nd lesion, 3rd lesion, and 4th lesion. Any pathologically identified malignant foci not previously described in the original imaging reports, were defined as undetected or missed lesions. Sensitivity was calculated for Mx, US and re-reviewed Mx for detecting the presence of the index cancer as well as additional satellite lesions.</p> <p>Results</p> <p>Pathological examination revealed 13 multifocal and 84 multicentric cancers with a total of 303 malignant foci (282 invasive and 21 non invasive). Original Mx and US reports had an overall sensitivity of 45.5% and 52.9%, respectively. Mx detected 83/97 index cancers with a sensitivity of 85.6%. The number of lesions <it>un</it>detected by original Mx was 165/303. The Mx pattern of breasts with undetected lesions were: fatty in 3 (1.8%); scattered fibroglandular density in 40 (24.3%), heterogeneously dense in 91 (55.1%) and dense in 31 (18.8%) cases. In breasts with an almost entirely fatty pattern, Mx sensitivity was 100%, while in fibroglandular or dense pattern it was reduced to 45.5%. Re-reviewed Mx detected only 3 additional lesions. The sensitivity of Mx was affected by the presence of dense breast tissue which obscured lesions or by an incorrect interpretation of suspicious findings.</p> <p>US detected 73/80 index cancers (sensitivity of 91.2%), US missed 117 malignant foci with a mean tumor diameter of 6.5 mm; the sensitivity was 52.9%</p> <p>Undetected lesions by US were those smallest in size and present in fatty breast or in the presence of microcalcifications without a visible mass.</p> <p>US sensitivity was affected by the presence of fatty tissue or by the extent of calcification.</p> <p>Conclusion</p> <p>Mx missed MMBC malignant foci more often in dense or fibroglandular breasts. US missed small lesions in mainly fatty breasts or when there were only microcalcifications. The combined sensitivity of both techniques to assess MMBC was 58%. We suggest larger studies on multimodality imaging.</p

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Assessing the impact of COVID-19 on liver cancer management (CERO-19).

BACKGROUND & AIMS: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems and it may have heavily impacted patients with liver cancer (LC). Herein, we evaluated whether the schedule of LC screening or procedures has been interrupted or delayed because of the COVID-19 pandemic. METHODS: An international survey evaluated the impact of the COVID-19 pandemic on clinical practice and clinical trials from March 2020 to June 2020, as the first phase of a multicentre, international, and observational project. The focus was on patients with hepatocellular carcinoma or intrahepatic cholangiocarcinoma, cared for around the world during the first COVID-19 pandemic wave. RESULTS: Ninety-one centres expressed interest to participate and 76 were included in the analysis, from Europe, South America, North America, Asia, and Africa (73.7%, 17.1%, 5.3%, 2.6%, and 1.3% per continent, respectively). Eighty-seven percent of the centres modified their clinical practice: 40.8% the diagnostic procedures, 80.9% the screening programme, 50% cancelled curative and/or palliative treatments for LC, and 41.7% modified the liver transplantation programme. Forty-five out of 69 (65.2%) centres in which clinical trials were running modified their treatments in that setting, but 58.1% were able to recruit new patients. The phone call service was modified in 51.4% of centres which had this service before the COVID-19 pandemic (n = 19/37). CONCLUSIONS: The first wave of the COVID-19 pandemic had a tremendous impact on the routine care of patients with liver cancer. Modifications in screening, diagnostic, and treatment algorithms may have significantly impaired the outcome of patients. Ongoing data collection and future analyses will report the benefits and disadvantages of the strategies implemented, aiding future decision-making. LAY SUMMARY: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems globally. Herein, we assessed the impact of the first wave pandemic on patients with liver cancer and found that routine care for these patients has been majorly disrupted, which could have a significant impact on outcomes

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Una camera a termoigrometria controllata, a tre celle separabili, per misure di permeabilità al vapore

In questo lavoro è descritta la progettazione e la realizzazione di una nuova apparecchiatura per le misure sperimentali della permeabilità al vapore dei materiali. E’ stato dimensionato, costruito e strumentato un box climatizzato, secondo i requisiti richiesti dalla normativa europea che si occupa di tali sperimentazioni. Tale lavoro vuole rappresentare la pratica attualizzazione, oltre che la continuazione, di una lunga serie di studi affrontati realizzando una prima serie di apparecchiature per le prove di permeabilità al vapore su campioni di legno. Riprendendo questi temi, il lavoro oggetto della seguente tesi di laurea affronta una concreta riprogettazione delle camere climatizzate precedenti, nell’intento di darne una realizzazione definitiva, in grado di consentire l’esecuzione delle prove di permeabilità al vapore su più materiali di diverso tipo contemporaneamente. Il nuovo box climatizzato, infatti, dà la possibilità di effettuare prove di tal genere su tre materiali, in maniera indipendente, soggetti alle stesse condizioni climatiche. Si è provveduto, inoltre, alla scelta di tutti i componenti necessari al corretto funzionamento della apparecchiatura, con riferimento agli strumenti relativi alla acquisizione dei dati sperimentali ed a quelli relativi al controllo continuo dei principali parametri in gioco. Lo studio delle condizioni termoigrometriche dell’aria che circonda un oggetto è assai importante ai fini di valutare quale effetto possano provocare su quest’ultimo eventuali rapidi scostamenti dalle condizioni di equilibrio (tra oggetto ed ambiente circostante) di temperatura ed umidità; rivolgendo particolare attenzione al controllo dell’umidità relativa, è noto come, in diverse situazioni, le variazioni di tale parametro comportino danni spesso irreparabili ad opere d'arte, influenzando, altresì, dimensioni e forme degli oggetti (i materiali organici in grado di assorbire acqua si gonfiano quando l’umidità relativa aumenta e si restringono quando, invece, essa diminuisce, con conseguenti deformazioni, variazioni di peso e rottura delle fibre), processi chimici (elevati valori di umidità relativa favoriscono reazioni chimiche di indebolimento delle fibre organiche, tipo tessili e carta, e di scolorimento delle tinture su sete, cotoni e lane), processi biologici (ambienti a temperature superiori a 20 °C con tasso di umidità relativa oltre il 65 % agevolano sia la formazione di muffe, che la sopravvivenza di numerosi insetti nocivi). Si può dire che la presenza di liquido tra le fibre del materiale provoca danni (corrosione dei metalli, formazione di muffe, imputridimento delle parti di legno); tali danni possono divenire anche distruttivi, nel momento in cui l’acqua assorbita nello strato isolante arriva al congelamento

Metamicrobiomics in herbivore beetles of the genus Cryptocephalus (Chrysomelidae): toward the understanding of ecological determinants in insect symbiosis

The Cryptocephalus marginellus (Coleoptera: Chrysomelidae) complex is composed by six species that are supposed to have originated by events of allo- or parapatric speciation. In the present study we investigated the alternative hypotheses that the bacterial communities associated with six populations of this species complex are shaped by environmental factors, or reflect the proposed pattern of speciation. The microbiota associated with the six populations, from five species of the complex, have been characterized through 16S rRNA pyrotag sequencing. Based on a 97% sequence similarity threshold, data were clustered into 381 OTUs, which were analyzed using a variety of diversity indices. The microbiota of C. acquitanus and C. marginellus (Calanques) were the most diverse (over 100 OTUs), while that from C. zoiai yielded less bacterial diversity (45 OTUs). Taxonomic assignment revealed Proteobacteria, Tenericutes and Firmicutes as the dominant components of these beetles’ microbiota. The most abundant genera were Ralstonia, Sphingomonas, Rickettsia, and Pseudomonas. Different strains of Rickettsia were detected in C. eridani and C. renatae. The analysis of β-diversity revealed high OTU turnover among the populations of C. marginellus complex, with only few shared species. Hierarchical clustering taking into account relative abundances of OTUs does not match the phylogeny of the beetles, therefore we hypothesize that factors other than phylogenetic constraints play a role in shaping the insects’ microbiota. Environmental factors that could potentially affect the composition of bacterial communities were tested by fitting them on the results of a multi-dimensional scaling analysis. No significant correlations were observed towards the geographic distances or the host plants, while the composition of the microbiota appeared associated with altitude. The metabolic profiles of the microbiotas associated with each population were inferred from bacterial taxonomy, and interestingly, the obtained clustering pattern was consistent with the host phylogeny.This work was partially supported by “Accordo di Programma, affermazione in Edolo del Centro di Eccellenza Università della Montagna” MIUR-Università degli Studi di Milano, prot. n. 1293–05/08/2011. JGZ has received support from the Spanish Ministry of Economy and Competitivity (project no. CGL2011–23820/BOS, with contribution from FEDER Funds).Peer reviewe

Molecular and serological evidence for the circulation of the tick symbiont Midichloria (Rickettsiales: Midichloriaceae) in different mammalian species.

Background The Midichloriaceae is a novel family of the order Rickettsiales, that encompasses intracellular bacteria associated with hard ticks (Ixodidae) and other arthropods. The most intensively investigated member of this family is Midichloria mitochondrii, a symbiotic bacterium of the sheep tick Ixodes ricinus, characterized by the capacity of multiplying inside the mitochondria. A recent study suggested that these bacteria might be inoculated into the human host during the tick bite. The purpose of this study was to determine the potential infectivity of Midichloria bacteria for non-human animals exposed to the risk of tick bite. Methods Blood from horses, cattle, sheep and dogs exposed to the risk of tick bite was included in this study. DNAs were extracted, and amplified using 16S ribosomal RNA primers conserved in the Midichloria genus. Furthermore, sera from dogs exposed to the risk of tick bite were analyzed in order to evaluate the presence of antibodies against the recombinant flagellar protein (rFliD) from M. mitochondrii using an ELISA test. Results Here we present two lines of evidence that support the possibility that bacteria from the genus Midichloria are inoculated into vertebrate hosts during a tick bite: (i) a direct evidence, i.e. the detection of circulating DNA from bacteria related with M. mitochondrii, in the blood of vertebrates exposed to tick parasitism; (ii) a further indirect evidence, i.e. the presence of antibodies against an antigen from M. mitochondrii in dogs exposed to the risk of tick bite. It is interesting to note that variability was detected in the Midichloria gene sequences recovered from positive animals, and that some of these sequences were identical to those generated from tick-associated Midichloria. Conclusions Based on the results, and on the overall information so far published on the genus Midichloria, we suggest that these bacteria are likely to represent a novel group of vector-borne agents, with the potential of infecting mammalian hosts. Whether inoculation of Midichloria bacteria could cause a true infection and pathological alteration in mammalian hosts is still to be determined. Surely, results emphasize the relevance of Midichloria bacteria in investigations on tick immunology and tick-bite markers