155 research outputs found
Heavy Residue Formation in 20 MeV/nucleon 197Au + 90Zr collisions
The yields and velocity distributions of heavy residues and fission fragments
from the reaction of 20 MeV/nucleon 197Au + 90Zr have been measured using the
MSU A1200 fragment separator. A bimodal distribution of residues is observed,
with one group, resulting from peripheral collisions, having fragment mass
numbers A=160-200, while the other group, resulting from ``hard'' collisions,
has A=120-160. This latter group of residues can be distinguished from fission
fragments by their lower velocities. A model combining deep-inelastic transfer
and incomplete fusion for the primary interaction stage and a statistical
evaporation code for the deexcitation stage has been used to describe the
properties of the product distributions.Comment: 19 pages, 6 figures, preprint submitted to Nucl. Phys.
On the alpha activity of natural tungsten isotopes
The indication for the alpha decay of 180-W with a half-life
T1/2=1.1+0.8-0.4(stat)+-0.3(syst)x10^18 yr has been observed for the first time
with the help of the super-low background 116-CdWO_4 crystal scintillators. In
conservative approach the lower limit on half-life of 180-W has been
established as T1/2>0.7x10^18 yr at 90% C.L. Besides, new T1/2 bounds were set
for alpha decay of 182-W, 183-W, 184-W and 186-W at the level of 10^20 yr.Comment: 16 pages, 8 figures, accepted in Phys. Rev.
Mass Parameterizations and Predictions of Isotopic Observables
We discuss the accuracy of mass models for extrapolating to very asymmetric
nuclei and the impact of such extrapolations on the predictions of isotopic
observables in multifragmentation. We obtain improved mass predictions by
incorporating measured masses and extrapolating to unmeasured masses with a
mass formula that includes surface symmetry and Coulomb terms. We find that
using accurate masses has a significant impact on the predicted isotopic
observables.Comment: 12 pages, 4 figure
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP
Promptly decaying lightest neutralinos and long-lived staus are searched for
in the context of light gravitino scenarios. It is assumed that the stau is the
next to lightest supersymmetric particle (NLSP) and that the lightest
neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector
at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of
the production of these particles is found. Hence, lower mass limits for both
kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is
found to be greater than 71.5 GeV/c^2. In the search for long-lived stau,
masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10
to 150 \eVcc . Combining this search with the searches for stable heavy leptons
and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc
may be set for the stau mas
Herschel observations of EXtra-Ordinary Sources (HEXOS): detecting spiral arm clouds by CH absorption lines
We have observed CH absorption lines (J = 3/2, N = 1 ← J = 1/2, N = 1) against the continuum source Sgr B2(M) using the Herschel/HIFI
instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities
and line widths are detected and identified. The narrower line width and lower column density clouds show “spiral arm” cloud characteristics,
while the absorption component with the broadest line width and highest column density corresponds to the gas from the Sgr B2 envelope. The
observations show that each “spiral arm” harbors multiple velocity components, indicating that the clouds are not uniform and that they have internal
structure. This line-of-sight through almost the entire Galaxy offers unique possibilities to study the basic chemistry of simple molecules in
diffuse clouds, as a variety of different cloud classes are sampled simultaneously. We find that the linear relationship between CH and H2 column
densities found at lower AV by UV observations does not continue into the range of higher visual extinction. There, the curve flattens, which
probably means that CH is depleted in the denser cores of these clouds
Dynamic analysis of repetitive decision-free discreteevent processes: The algebra of timed marked graphs and algorithmic issues
A model to analyze certain classes of discrete event dynamic systems is presented. Previous research on timed marked graphs is reviewed and extended. This model is useful to analyze asynchronous and repetitive production processes. In particular, applications to certain classes of flexible manufacturing systems are provided in a companion paper. Here, an algebraic representation of timed marked graphs in terms of reccurrence equations is provided. These equations are linear in a nonconventional algebra, that is described. Also, an algorithm to properly characterize the periodic behavior of repetitive production processes is descrbed. This model extends the concepts from PERT/CPM analysis to repetitive production processes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44155/1/10479_2005_Article_BF02248590.pd
CSF1R inhibitor JNJ-40346527 attenuates microglial proliferation and neurodegeneration in P301S mice
Neuroinflammation and microglial activation are significant processes in Alzheimer's disease pathology. Recent genome-wide association studies have highlighted multiple immune-related genes in association with Alzheimer's disease, and experimental data have demonstrated microglial proliferation as a significant component of the neuropathology. In this study, we tested the efficacy of the selective CSF1R inhibitor JNJ-40346527 (JNJ-527) in the P301S mouse tauopathy model. We first demonstrated the anti-proliferative effects of JNJ-527 on microglia in the ME7 prion model, and its impact on the inflammatory profile, and provided potential CNS biomarkers for clinical investigation with the compound, including pharmacokinetic/pharmacodynamics and efficacy assessment by TSPO autoradiography and CSF proteomics. Then, we showed for the first time that blockade of microglial proliferation and modification of microglial phenotype leads to an attenuation of tau-induced neurodegeneration and results in functional improvement in P301S mice. Overall, this work strongly supports the potential for inhibition of CSF1R as a target for the treatment of Alzheimer's disease and other tau-mediated neurodegenerative diseases
- …