1,185 research outputs found
LLRF upgrade status at the KEK Photon Factory 2.5 GeV ring
In 2023, we are replacing the LLRF system for the KEK-PF 2.5 GeV ring. The
new system is composed of digital boards such as eRTM, AMC, and {\mu}RTM, based
on the MTCA.4 standard. In our system, we adopted the non-IQ direct sampling
method for RF detection. We set the sampling frequency at 8/13 (307.75 MHz) of
the RF frequency, where the denominator (13) is the divisor of the harmonic
number (312) of the storage ring. This allows us to detect the transient
variation of the cavity voltage that is synchronized with the beam revolution.
We also plan to compensate for the voltage variation by implementing a
feedforward technique. These functions will be useful in a double RF system for
KEK future synchrotron light source. Production and installation of the new
system were complete and the new system is under commissioning. In this
presentation, we introduce our new system and report the upgrade status.Comment: Talk presented at LLRF Workshop 2023 (LLRF2023, arXiv: 2310.03199
Frequency, nature, effects, and correlates of conflicts of interest in published clinical cancer research
BACKGROUND: Relationships between clinical researchers and industry are becoming increasingly complex. The frequency and impact of conflicts of interest in the full range of high-impact, published clinical cancer research is unknown. METHODS: The authors reviewed cancer research published in 8 journals in 2006 to determine frequency of self-reported conflicts of interest, source of study funding, and other characteristics. They assessed associations between the likelihood of conflicts of interest and other characteristics by using chi-squared testing. They also compared the likelihood of positive outcome in randomized trials with and without conflicts of interest by chi-squared testing. RESULTS: The authors identified 1534 original oncology studies; 29% had conflicts of interest (including industrial funding) and 17% declared industrial funding. Conflicts of interest varied by discipline ( P < .001), continental origin ( P < .001), and sex ( P < .001) of the corresponding author and were most likely in articles with corresponding authors from departments of medical oncology (45%), those from North America (33%), and those with male first and senior authors (37%). Frequency of conflicts also varied considerably depending upon disease site studied. Studies with industrial funding were more likely to focus on treatment (62% vs 36%; P < .001), and randomized trials that assessed survival were more likely to report positive survival outcomes when a conflict of interest was present ( P = .04). CONCLUSIONS: Conflicts of interest characterize a substantial minority of clinical cancer research published in high-impact journals. Therefore, attempts to disentangle the cancer research effort from industry merit further attention, and journals should embrace both rigorous standards of disclosure and heightened scrutiny when conflicts exist. Cancer 2009. © 2009 American Cancer Society.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63065/1/24315_ftp.pd
Species Abundance Patterns in Complex Evolutionary Dynamics
An analytic theory of species abundance patterns (SAPs) in biological
networks is presented. The theory is based on multispecies replicator dynamics
equivalent to the Lotka-Volterra equation, with diverse interspecies
interactions. Various SAPs observed in nature are derived from a single
parameter. The abundance distribution is formed like a widely observed
left-skewed lognormal distribution. As the model has a general form, the result
can be applied to similar patterns in other complex biological networks, e.g.
gene expression.Comment: 4 pages, 3 figures. Physical Review Letters, in pres
Photoelectron Angular Distributions for Two-photon Ionization of Helium by Ultrashort Extreme Ultraviolet Free Electron Laser Pulses
Phase-shift differences and amplitude ratios of the outgoing and
continuum wave packets generated by two-photon ionization of helium atoms are
determined from the photoelectron angular distributions obtained using velocity
map imaging. Helium atoms are ionized with ultrashort extreme-ultraviolet
free-electron laser pulses with a photon energy of 20.3, 21.3, 23.0, and 24.3
eV, produced by the SPring-8 Compact SASE Source test accelerator. The measured
values of the phase-shift differences are distinct from scattering phase-shift
differences when the photon energy is tuned to an excited level or Rydberg
manifold. The difference stems from the competition between resonant and
non-resonant paths in two-photon ionization by ultrashort pulses. Since the
competition can be controlled in principle by the pulse shape, the present
results illustrate a new way to tailor the continuum wave packet.Comment: 5 pages, 1 table, 3 figure
HIV Types, Groups, Subtypes and Recombinant Forms: Errors in Replication, Selection Pressure and Quasispecies
HIV-1 is a chimpanzee virus which was transmitted to humans by several zoonotic events resulting in infection with HIV-1 groups M P, and in parallel transmission events from sooty mangabey monkey viruses leading to infections with HIV-2 groups A H. Both viruses have circulated in the human population for about 80 years. In the infected patient, HIV mutates, and by elimination of some of the viruses by the action of the immune system individual quasispecies are formed. Along with the selection of the fittest viruses, mutation and recombination after superinfection with HIV from different groups or subtypes have resulted in the diversity of their patterns of geographic distribution. Despite the high variability observed, some essential parts of the HIV genome are highly conserved. Viral diversity is further facilitated in some parts of the HIV genome by drug selection pressure and may also be enhanced by different genetic factors, including HLA in patients from different regions of the world. Viral and human genetic factors influence pathogenesis. Viral genetic factors are proteins such as Tat, Vif and Rev. Human genetic factors associated with a better clinical outcome are proteins such as APOBEC, langerin, tetherin and chemokine receptor 5 (CCR5) and HLA B27, B57, DRB1{*}1303, KIR and PARD3B. Copyright (C) 2012 S. Karger AG, Base
Sentinel nodes identified by computed tomography-lymphography accurately stage the axilla in patients with breast cancer
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