2,949 research outputs found
Classical and Quantum-like approaches to Charged-Particle Fluids in a Quadrupole
A classical description of the dynamics of a dissipative charged-particle
fluid in a quadrupole-like device is developed. It is shown that the set of the
classical fluid equations contains the same information as a complex function
satisfying a Schrodinger-like equation in which Planck's constant is replaced
by the time-varying emittance, which is related to the time-varying temperature
of the fluid. The squared modulus and the gradient of the phase of this complex
function are proportional to the fluid density and to the current velocity,
respectively. Within this framework, the dynamics of an electron bunch in a
storage ring in the presence of radiation damping and quantum-excitation is
recovered. Furthermore, both standard and generalized (including dissipation)
coherent states that may be associated with the classical particle fluids are
fully described in terms of the above formalism.Comment: LaTex, to appear in Physica Script
COVID-19 NHS infection control strategy: errare humanum est, perseverare autem diabolicum
A recent BMJ Editorial (“Getting it right in the pandemic”) has discussed examples of countries that have done better than others in responding to COVID‐19 pandemic and, conversely, those policymakers and health systems that got it wrong. (Loder, 2020) There is little doubt that, when facing a pandemic with a high speed of onset and transmission, “nobody should be surprised that errors were made” (Adebowale et al, 2020) and “what it was done some weeks ago is not what we would do today”
Coherent States for Particle Beams in the Thermal Wave Model
In this paper, by using an analogy among {\it quantum mechanics}, {\it
electromagnetic beam optics in optical fibers}, and {\it charge particle beam
dynamics}, we introduce the concept of {\it coherent states} for charged
particle beams in the framework of the {\it Thermal Wave Model} (TWM). We give
a physical meaning of the Gaussian-like coherent structures of charged particle
distribution that are both naturally and artificially produced in an
accelerating machine in terms of the concept of coherent states widely used in
quantum mechanics and in quantum optics. According to TWM, this can be done by
using a Schr\"{o}dinger-like equation for a complex function, the so-called
{\it beam wave function} (BWF), whose squared modulus is proportional to the
transverse beam density profile, where Planck's constant and the time are
replaced by the transverse beam emittance and by the propagation coordinate,
respectively. The evolution of the particle beam, whose initial BWF is assumed
to be the simplest coherent state (ground-like state) associated with the beam,
in an infinite 1-D quadrupole-like device with small sextupole and octupole
aberrations, is analytically and numerically investigated.Comment: 21 pages, Late
Osteonecrosis of the Jaw Associated with Antiangiogenics in Antiresorptive-Naive Patient: A Comprehensive Review of the Literature
Objectives. To review the available literature on medication-related osteonecrosis of the jaw (MRONJ) associated with antiangiogenics in antiresorptive-naïve individuals. Methods. A literature search was performed using MEDLINE via PubMed, EMBASE, and Web of Science in December 2017. Results. We identified reports describing a total of 35 antiresorptive drugs-naïve patients who developed antiangiogenic-related MRONJ. The mean age of these patients was 59.06 years and the F : M ratio was 4 : 5. The most common underlying disease was metastatic renal cell cancer. Pain to the mandible was the most common complaint (34.29%) and the majority of patients presented with bone exposure. The mean duration of intravenous and oral antiangiogenics before MRONJ development was 6.5 and 16.72 months, respectively. The most common additional risk factor was dental extraction (37.14%). Almost half of the MRONJ patients (48.57%) received surgical treatment. 18 patients (62.06%) were reported to have disease resolution within an average time of 6.75 months. Conclusion. MRONJ associated with antiangiogenic therapy in antiresorptive-naïve patients is a rare but potentially serious adverse effect. Available data suggests that there might be notable differences between MRONJ associated with antiangiogenics and antiresorptives; however, further prospective well-designed studies are required
Self modulated dynamics of a relativistic charged particle beam in plasma wake field excitation
Self modulated dynamics of a relativistic charged particle beam is reviewed
within the context of the theory of plasma wake field excitation. The
self-consistent description of the beam dynamics is provided by coupling the
Vlasov equation with a Poisson-type equation relating the plasma wake potential
to the beam density. An analysis of the beam envelope self-modulation is then
carried out and the criteria for the occurrence of the instability are
discussed thereby.Comment: This is a 10 pages manuscript which contain 4 figures. This
manuscript is recently submitted in 'Nuclear Instruments and Methods in
Physics Research Section A' as a proceeding of the conference 'EAAC 2015
Orofacial Granulomatosis
Orofacial granulomatosis (OFG) is an uncommon chronic inflammatory disorder of the orofacial region. It is characterized by subepithelial noncaseating granulomas and has a spectrum of possible clinical manifestations ranging from subtle oral mucosal swelling to permanent disfiguring fibrous swelling of the lips and face. Etiopathogenesis is unknown. A range of systemic granulomatous disorders, including Crohn disease and sarcoidosis, may cause orofacial manifestations that cannot be distinguished from those of OFG. Treatment of OFG has proven difficult and unsatisfactory, with no single therapeutic model showing consistent efficacy in reducing orofacial swelling and mucosal inflammation
Image Correlation-Based Identification of Fracture Parameters for Structural Adhesives
We consider the identification problem of a cohesive model using kinematic full-field data obtained via digital image correlation during the fracture test of an adhesive joint. A criterion is presented for selecting measurements that exhibit optimal features for identification purposes. The proposed selection scheme is constructed using the sensitivity information and its performances are evaluated at varying noise-to-signal ratio
Probing the radial temperature structure of protoplanetary disks with Herschel/HIFI
Herschel/HIFI spectroscopic observations of CO J=10-9, CO J=16-15 and [CII]
towards HD 100546 are presented. The objective is to resolve the velocity
profile of the lines to address the emitting region of the transitions and
directly probe the distribution of warm gas in the disk. The spectra reveal
double-peaked CO line profiles centered on the systemic velocity, consistent
with a disk origin. The J=16-15 line profile is broader than that of the J=10-9
line, which in turn is broader than those of lower J transitions (6-5, 3-2,
observed with APEX), thus showing a clear temperature gradient of the gas with
radius. A power-law flat disk model is used to fit the CO line profiles and the
CO rotational ladder simultaneously, yielding a temperature of T_0=1100 \pm 350
K (at r_0 = 13 AU) and an index of q=0.85 \pm 0.1 for the temperature radial
gradient. This indicates that the gas has a steeper radial temperature gradient
than the dust (mean q_{dust} ~ 0.5), providing further proof of the thermal
decoupling of gas and dust at the disk heights where the CO lines form. The
[CII] line profile shows a strong single-peaked profile red-shifted by 0.5 km
s-1 compared to the systemic velocity. We conclude that the bulk of the [CII]
emission has a non-disk origin (e.g., remnant envelope or diffuse cloud).Comment: Accepted for publication in ApJ
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