Beam dynamics studies for the FCC-ee collimation system design

The electron-positron Future Circular Collider (FCC-ee) is being designed for stored beam energies up to 20.7 MJ, a value almost two orders of magnitude higher than any previous lepton collider. Considering the risk of any beam losses causing experimental backgrounds, magnet quenches, or even damage, a halo collimation system is under study to protect the most sensitive equipment from unavoidable losses. Beam dynamics and tracking studies are key aspects to evaluate the cleaning performance of the collimation system, and are essential in an iterative process to converge on an optimum performance. The first results of such studies, exploring various configurations of materials and collimator lengths, are presented, including also estimated beam loss distributions around the ring. In addition, an impact parameter scan on the primary collimators is performed to identify the most critical case for the protection of sensitive equipment

Practical Approach to the Diagnosis of the Vulvo-Vaginal Stromal Tumors: An Overview

Background: The category of the "stromal tumors of the lower female genital tract" encompasses a wide spectrum of lesions with variable heterogeneity, which can be nosologically classified on the basis of their morphologic and immunohistochemical profiles as deep (aggressive) angiomyxoma (DAM), cellular angiofibroma (CAF), angiomyofibroblastoma (AMFB) or myofibroblastoma (MFB). Despite the differential diagnosis between these entities being usually straightforward, their increasingly recognized unusual morphological variants, along with the overlapping morphological and immunohistochemical features among these tumours, may raise serious differential diagnostic problems. Methods and Results: The data presented in the present paper have been retrieved from the entire published literature on the PubMed website about DAM, CAF, AFMB and MFB from 1984 to 2021. The selected articles are mainly represented by small-series, and, more rarely, single-case reports with unusual clinicopathologic features. The present review focuses on the diagnostic clues of the stromal tumours of the lower female genital tract to achieve a correct classification. The main clinicopathologic features of each single entity, emphasizing their differential diagnostic clues, are discussed and summarized in tables. Representative illustrations, including the unusual morphological variants, of each single tumour are also provided. Conclusion: Awareness by pathologists of the wide morphological and immunohistochemical spectrum exhibited by these tumours is crucial to achieve correct diagnoses and to avoid confusion with reactive conditions or other benign or malignant entities

Parametric Study of Heat Deposition from Collision Debris into the Insertion Superconducting Magnets for the LHC Luminosity Upgrade

With a new geometry in a higher luminosity environment, the power deposition in the superconducting magnets becomes a critical aspect to analyze and to integrate in the insertion design. In this paper, we quantify the power deposited in magnets insertion at variable positions from the interaction point (IP). A fine characterization of the debris due to the proton-proton collisions at 7 TeV, shows that the energetic particles in the very forward direction give rise to non intuitive dependences of the impacting energy on the magnet front face and inner surface. The power deposition does not vary significantly with the distance to the interaction point, because of counterbalancing effects of different contributions to power deposition. We have found out that peak power density in the magnet insertion does not vary significantly with or without the Target Absorber Secondaries (TAS) protection

The wide morphological spectrum of deep (Aggressive) angiomyxoma of the vulvo-vaginal region: A clinicopathologic study of 36 cases, including recurrent tumors

Background: Deep angiomyxoma (DAM) is currently included in the category of "specific stromal tumors of the lower female genital tract", along with angiomyofibroblastoma, cellular angiofibroma and myofibroblastoma. Given the high rate of local recurrences, it is crucial to recognize DAM from other tumors that possess indolent behaviour. In the present paper, we analyzed the morphological and immunohistochemical features of 42 surgically-resected vulvo-vaginal DAMs (36 primary and 6 recurrent lesions) in order to widen the morphological spectrum of this uncommon tumor. Methods: A series of 36 cases of surgically-resected primary vulvo-vaginal DAMs were retrospectively collected. Locally recurrent tumors were also available for six of these cases. Results: Out of the primary tumors, 25 out of 36 exhibited the classic-type morphology of DAM. In the remaining cases (11/36 cases), the following uncommon features, which sometimes coexist with one another, were observed: (i) alternating myxoid and collagenized/fibrous areas; (ii) hypercellular areas; (iii) neurofibroma-like appearance; (iv) perivascular hyalinization; (v) microcystic/reticular stromal changes; (vi) "microvascular growth pattern"; (vii) perivascular cuffing; (viii) nodular leiomyomatous differentiation; (ix) hypocellular and fibro-sclerotic stroma. Among the six locally recurrent tumors the following features were observed: (i) classic-type morphology; (ii) hypocellular fibro-sclerotic stroma; (iii) extensive perivascular hyalinization, lumen obliteration and formation of confluent nodular sclerotic masses; (iv) hypercellularity. Immunohistochemically, the neoplastic cells of classic-type DAM in both primary and recurrent tumors were diffusely stained with desmin, suggesting a myofibroblastic nature; in contrast, the neoplastic cells showing elongated fibroblastic-like morphology and set in collagenized/fibrosclerotic stroma in both primary and recurrent tumors were negative or only focally stained with desmin, which is consistent with a fibroblastic profile. Conclusion: Although diagnosis of DAM is usually straightforward if typical morphology is encountered, diagnostic problems may arise when a pathologist is dealing with unusual morphological features, especially hypercellularity, extensive collagenous/fibrosclerotic stroma or neurofibroma-like appearance

Low-Intensity Vibration Protects the Weight-Bearing Skeleton and Suppresses Fracture Incidence in Boys With Duchenne Muscular Dystrophy: A Prospective, Randomized, Double-Blind, Placebo-Controlled Clinical Trial

The ability of low-intensity vibration (LIV) to combat skeletal decline in Duchenne Muscular Dystrophy (DMD) was evaluated in a randomized controlled trial. Twenty DMD boys were enrolled, all ambulant and treated with glucocorticoids (mean age 7.6, height-adjusted Z-scores [HAZ] of hip bone mineral density [BMD] −2.3). Ten DMD boys were assigned to stand for 10 min/d on an active LIV platform (0.4 g at 30 Hz), while 10 stood on a placebo device. Baseline and 14-month bone mineral content (BMC) and BMD of spine, hip, and total body were measured with DXA, and trabecular bone density (TBD) of tibia with quantitative computed tomography (QCT). All children tolerated the LIV intervention well, with daily compliance averaging 78%. At 14 months, TBD in the proximal and distal tibia remained unchanged in placebo subjects (−1.0% and −0.2%), while rising 3.5% and 4.6% in LIV subjects. HAZ for hip BMD and BMC in the placebo group declined 22% and 13%, respectively, contrasting with no change from baseline (0.9% and 1.4%) in the LIV group. Fat mass in the leg increased 32% in the placebo group, contrasting with 21% in LIV subjects. Across the 14-month study, there were four incident fractures in three placebo patients (30%), with no new fractures identified in LIV subjects. Despite these encouraging results, a major limitation of the study is—despite randomized enrollment—that there was a significant difference in age between the two cohorts, with the LIV group being 2.8y older, and thus at greater severity of disease. In sum, these data suggest that noninvasive LIV can help protect the skeleton of DMD children against the disease progression, the consequences of diminished load bearing, and the complications of chronic steroid use. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research

Studies of layout and cleaning performance for the FCC–ee collimation system

The collimation system of the electron-positron Future Circular Collider (FCC-ee) will have two main tasks: protect equipment from the multi-MJ beams and mitigate detector backgrounds. An integrated collimation system layout is presented, including beam halo collimation system in one insertion and synchrotron radiation collimation around the experimental interaction points. The Z-production operating mode is considered, which has a beam energy of 45.6 GeV and a stored beam energy of 17.8 MJ, making it the most critical one for machine protection. The collimation insertion optics, aperture model, and collimation configuration for this mode are presented. The beam loss cleaning performance of the collimation system is studied for selected beam loss scenarios using a set of novel tools that enable multi-turn tracking simulations

Nonlinear resonant tunneling in systems coupled to quantum reservoirs

An adiabatic approximation in terms of instantaneous resonances is developed to study the steady-state and time-dependent transport of interacting electrons in biased resonant tunneling heterostructures. The resulting model consists of quantum reservoirs coupled to regions where the system is described by nonlinear ordinary differential equations and has a general conceptual interest.Comment: 4 pages, 3 postscript figure

Application of latent class analysis in assessing the awareness, attitude, practice and satisfaction of paediatricians on sleep disorder management in children in Italy.

AIM: To identify subgroups regarding paediatricians' awareness, attitude, practice and satisfaction about management of Sleep-Disordered Breathing (SDB) in Italy using Latent Class Analysis (LCA). METHODS: A cross-sectional study was conducted on a large sample of Italian paediatricians. Using a self-administered questionnaire, the study collected information on 420 Paediatric Hospital Paediatricians (PHPs) and 594 Family Care Paediatricians (FCPs). LCA was used to discover underlying response patterns, thus allowing identification of respondent groups with similar awareness, attitude, practice and satisfaction. A logistic regression model was used to investigate which independent variables influenced latent class membership. Analyses were performed using R 3.5.2 software. A p-value<0.05 was considered statistically significant. RESULTS: Two classes were identified: Class 1 (n = 368, 36.29%) "Untrained and poorly satisfied" and Class 2 (n = 646, 63.71%) "Trained and satisfied." Involving paediatric pneumologists or otorhinolaryngologists in clinical practice was associated with an increased probability of Class 2 membership (OR = 5.88, 95%CI [2.94-13.19]; OR = 15.95, 95% CI [10.92-23.81] respectively). Examining more than 20 children with SDB during the last month decreased the probability of Class 2 membership (OR = 0.29, 95% CI [0.14-0.61]). FCPs showed a higher probability of Class 2 membership than PHPs (OR = 4.64, 95% CI [3.31-6.55]). CONCLUSIONS: These findings suggest that the LCA approach can provide important information on how education and training could be tailored for different subgroups of paediatricians. In Italy standardized educational interventions improving paediatricians' screening of SDB are needed in order to guarantee efficient management of children with SDB and reduce the burden of disease