Energy Deposition in the Triplet and TAS Issues

Energy and power deposition in the low-beta insertion magnets may be the limiting factor in the choiche and/or performance for luminosity upgrade configuration for LHC. In this paper, after a general review of the problem about the type and properties of the secondary particles, the effect of the Target Secondary Absorber (TAS), for different distance l* of the insertion from the Interaction Point (I.P.) in various configurations is reported. Then the effect of the magnetic sequence of the quadrupoles for the two crossing plane, horizontal and vertical (H,V) is evaluated. Moreover the effect of the magnetic field of the solenoid is computed. All theese parametric studies tend to have a scaling law of the energy deposition in the insertion magnets vs. all the parametrs involved

Occurrence and status of the European Pond Turtle, Emys orbicularis hellenica (Valenciennes, 1833), on Aegean and Ionian Islands (Greece, Turkey)

A study on the occurrence of Emys orbicularis in the Aegean, published in 2012, is here extended to the Ionian Islands. For the first time, a status analysis has also been carried out for the individual islands. Emys orbicularis is found on 11 Greek islands and one Turkish. Its presence on the big islands of Rhodes and Chios has not been ascertained so far, while for four previously mentioned islands there is no confirmation. On Corfu and Lesbos there are still viable larger Emys populations. Most other island occurrences are characterized by small populations. On Kefalonia, Zakynthos, Thassos and Samos, E. orbicularis is in danger of extinction because the wetland biotopes are threatened. In the meantime, many wetlands have been placed under protection. The enforcement of these nature conservation regulations needs to be monitored, and E. orbicularis can be a lead species for such monitoring

Occurrence and tentative population status of the Balkan Terrapin (Mauremys rivulata, Valenciennes, 1833) on Greek islands

The distribution of Mauremys rivulata on Aegean islands was summarized by Broggi in 2012. Here, the study area encompasses all Greek islands, including the Ionian Islands, and the two Turkish islands of Gökceada and Bozcaada. For the first time, I attempt to estimate the status and size of the populations on the islands. This is a subjective assessment based on my personal visits to most islands and not on IUCN criteria. Mauremys rivulata was found on 29 Greek islands, plus two Turkish islands in the Aegean Sea. Five previously mentioned sites are doubtful, and on the three islands of Sifnos, Syros and Ithaca the species appears to be extinct. On 12 islands I assess its status as “threatened with extinction”. On seven, mostly larger, islands its populations are probably less vulnerable. Efforts must be made for the long-term protection of M. rivulata on the Greek islands

Energy Deposition Patterns in the LHC Inner Triplet and Their Impact on the Phase II Luminosity Upgrade

Recent studies show that the energy deposition for the LHC Phase I luminosity upgrade, aiming at a peak luminosity 2.5×10**34 cm**-2s**-1, can be handled by appropriate shielding. The Phase II upgrade aims at a further increase of peak luminosity by a factor 4, possibly using Nb$_{3}$Sn quadrupoles. This paper describes how the main features of the triplet layout, such as quadrupole lengths, gaps between magnets, and aperture, affect the energy deposition in the insertion. We demonstrate how the energy deposition patterns depend on the triplet lay-out. An additional variable which is taken into account is the choice of conductor, i.e. solutions with Nb-Ti and Nb$_{3}$Sn are compared. Nb$_{3}$Sn technology gives possibilities for increasing the magnet apertures and space for new shielding solutions. Our studies give an indication on the possibility of managing energy deposition for the Phase II upgrade

Picard group of K3 surfaces over finite fields

The aim of this work is to provide a method to find explicitly generators for the Picard group of a K3 surface of degree four defined over a finite field. This work has been motivated primarily by the difficulty related to this problem, and by the lack of examples in the literature. Another question related to this problem is if given a K3 surface of degree 4 defined over a finite field, is it possible to determine the minimal degree of a non complete intersection curve lying over it. We could not answer completely to this question, but we were still able to find algorithms to determine whether or not it contains a conic defined over an extension of the base field. We were also able to determine an algorithm to find twisted cubics defined over the base field in case it is F2

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

Energy Deposited in the High Luminosity Inner Triplets of the LHC by Collision Debris

The 14 TeV center of mass proton-proton collisions in the LHC produce not only debris interesting for physics but also showers of particles ending up in the accelerator equipment, in particular in the superconducting magnet coils. Evaluations of this contribution to the heat, that has to be transported by the cryogenic system, have been made to guarantee that the energy deposition in the superconducting magnets does not exceed limits for magnet quenching and the capacity of the cryogenic system. The models of the LHC base-line are detailed and include description of, for energy deposition, essential elements like beam-pipes and corrector magnets. The evaluations made using the Monte-Carlo code FLUKA are compared to previous studies using MARS. For the comparison and consolidation of the calculations, a dedicated study of code comparison for a reduced setup was made

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

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