1,720 research outputs found
MONDO: A neutron tracker for particle therapy secondary emission fluxes measurements
A charged particle passing through matter releases a considerable amount of energy at the end of its path. Thus, thanks to the spatial distribution of the deposited energy, particle therapy allows treating tumors with greater accuracy and efficiency than conventional radiotherapy. However, during the treatments, several secondary particles are produced from the interactions between therapeutic beams and human tissues and contribute to the total dose delivered to the patient. Since neutrons can release a significant dose far away from the tumour region, a precise measurement of their flux, production energy and angle distribution is eagerly needed to improve the treatment planning system and to estimate the normal tissue toxicity in the target region and establish if/where there could be the risk of secondary neoplasms. The MONDO (MOnitor for Neutron Dose in hadrOntherapy) project aims at detecting secondary neutrons with high efficiency and good backtracking precision
Human performance control monitoring systems Interim report no. 2
Computer program to simulate second order servo system dynamics under automatic and manual contro
Human performance control monitoring system Final report, Jan. 1965 - Feb. 1966
Computer program simulation of servomechanism controlled by adaptive logic element trained by monitoring of human performance - mathematical mode
MONDO: A tracker for the characterization of secondary fast and ultrafast neutrons emitted in particle therapy
Breaking the electroweak symmetry and supersymmetry by a compact extra dimension
We revisit in some more detail a recent specific proposal for the breaking of
the electroweak symmetry and of supersymmetry by a compact extra dimension.
Possible mass terms for the Higgs and the matter hypermultiplets are considered
and their effects on the spectrum analyzed. Previous conclusions are reinforced
and put on firmer ground.Comment: 25 pages, LaTeX, 9 eps figure
Characterisation of the secondary-neutron production in particle therapy treatments with the MONDO tracking detector
Particle Therapy (PT) is a non-invasive technique that exploits charged light ions for the irradiation of tumours that cannot be effectively treated with surgery or conventional radiotherapy. While the largest dose fraction is released to the tumour volume by the primary beam, a non-negligible amount of additional dose is due to the beam fragmentation that occurs along the path towards the target volume. In particular, the produced neutrons are particularly dangerous as they can release their energy far away from the treated area, increasing the risk of developing a radiogenic secondary malignant neoplasm after undergoing a treatment. A precise measurement of the neutron flux, energy spectrum and angular distributions is eagerly needed in order to improve the treatment planning system software, so as to predict the normal tissue toxicity in the target region and the risk of late complications in the whole body. The MONDO (MOnitor for Neutron Dose in hadrOntherapy) project is dedicated to the characterisation of the secondary ultra-fast neutrons ([20-400] MeV energy range) produced in PT. The neutron tracking system exploits the reconstruction of the recoil protons produced in two consecutive (n, p) elastic scattering interactions to measure simultaneously the neutron incoming direction and energy. The tracker active media is a matrix of thin squared scintillating fibers arranged in orthogonally oriented layers that are read out by a sensor (SBAM) based on SPAD (Single-Photon Avalanche Diode) detectors developed in collaboration with the Fondazione Bruno Kessler (FBK)
A Large Mass Hierarchy from a Small Extra Dimension
We propose a new higher-dimensional mechanism for solving the Hierarchy
Problem. The Weak scale is generated from a large scale of order the Planck
scale through an exponential hierarchy. However, this exponential arises not
from gauge interactions but from the background metric (which is a slice of
AdS_5 spacetime). This mechanism relies on the existence of only a single
additional dimension. We demonstrate a simple explicit example of this
mechanism with two three-branes, one of which contains the Standard Model
fields. The experimental consequences of this scenario are new and dramatic.
There are fundamental spin-2 excitations with mass of weak scale order, which
are coupled with weak scale as opposed to gravitational strength to the
standard model particles. The phenomenology of these models is quite distinct
from that of large extra dimension scenarios; none of the current constraints
on theories with very large extra dimensions apply.Comment: 9 pages, LaTe
Clinical relevance and treatment of nonautoimmune anemia in chronic lymphocytic leukemia
Anemia has an unfavorable impact on quality of life in chronic lymphocytic leukemia (CLL), increases the likelihood of receiving blood transfusions, and eventually has a negative impact on overall survival. Although discrepancies in perception of health-related quality of life between doctors and patients lead to the undertreatment of anemia, CLL patients undergoing chemotherapy who have a hemoglobin level <10 g/dL should be considered for treatment with erythropoiesis-stimulating agents. For hemoglobin values of 10–12 g/dL, the role of performance status and comorbidities should not be underestimated. In this setting, the evaluation of physical fitness using the Cumulative Illness Rating Scale should help physicians to identify those patients with hemoglobin levels of 10–12 g/dL who are suitable for therapy with erythropoiesis-stimulating agents. Finally, the increasing use of aggressive approaches to therapy should encourage physicians towards appropriate management of chemotherapy-induced anemia in CLL patients
Brane fluctuations and suppression of Kaluza-Klein mode couplings
In higher dimensional models where the gauge and gravity fields live in the
bulk and the matter fields only in a brane, we point out the importance of the
brane (transverse) coordinate modes, which are the Nambu-Goldstone bosons
appearing as a result of spontaneous breaking of the translation symmetry. The
brane recoil effect suppresses the couplings of higher Kaluza-Klein modes to
the matter, and gives a natural resolution to the divergence problem caused by
the exchange of infinitely many Kaluza-Klein modes.Comment: 11 pages, 1 eps figure, references adde
Fermion Mass Hierarchies and Small Mixing Angles from Extra Dimensions
In this paper we study renormalization-group evolutions of Yukawa matrices
enhanced by Kaluza-Klein excited modes and analyze their infrared fixed-point
structure. We derive necessary conditions to obtain hierarchies between
generations on the fixed point. These conditions restrict how the fields in the
models can extend to higher dimension. Several specific mechanisms to realize
the conditions are presented. We also take account of generation mixing effects
and find a scenario where the mixing angles become small at low energy even
with large initial values at high-energy scale. A toy model is shown to lead
realistic quark mass matrices.Comment: 23 pages, 7 figures, LaTeX, a supplementary explanation and
references adde
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