697 research outputs found
Isotope shift in the dielectronic recombination of three-electron ^{A}Nd^{57+}
Isotope shifts in dielectronic recombination spectra were studied for Li-like
^{A}Nd^{57+} ions with A=142 and A=150. From the displacement of resonance
positions energy shifts \delta E^{142,150}(2s-2p_1/2)= 40.2(3)(6) meV
(stat)(sys)) and \delta E^{142,150}(2s-2p_3/2) = 42.3(12)(20) meV of 2s-2p_j
transitions were deduced. An evaluation of these values within a full QED
treatment yields a change in the mean-square charge radius of ^{142,150}\delta
= -1.36(1)(3) fm^2. The approach is conceptually new and combines the
advantage of a simple atomic structure with high sensitivity to nuclear size.Comment: 10 pages, 3 figures, accepted for publication in Physical Review
Letter
The maximum modulus of a trigonometric trinomial
Let Lambda be a set of three integers and let C_Lambda be the space of
2pi-periodic functions with spectrum in Lambda endowed with the maximum modulus
norm. We isolate the maximum modulus points x of trigonometric trinomials T in
C_Lambda and prove that x is unique unless |T| has an axis of symmetry. This
permits to compute the exposed and the extreme points of the unit ball of
C_Lambda, to describe how the maximum modulus of T varies with respect to the
arguments of its Fourier coefficients and to compute the norm of unimodular
relative Fourier multipliers on C_Lambda. We obtain in particular the Sidon
constant of Lambda
Direct observation of long-lived isomers in Bi
Long-lived isomers in 212Bi have been studied following 238U projectile
fragmentation at 670 MeV per nucleon. The fragmentation products were injected
as highly charged ions into the GSI storage ring, giving access to masses and
half-lives. While the excitation energy of the first isomer of 212Bi was
confirmed, the second isomer was observed at 1478(30) keV, in contrast to the
previously accepted value of >1910 keV. It was also found to have an extended
Lorentz-corrected in-ring halflife >30 min, compared to 7.0(3) min for the
neutral atom. Both the energy and half-life differences can be understood as
being due a substantial, though previously unrecognised, internal decay branch
for neutral atoms. Earlier shell-model calculations are now found to give good
agreement with the isomer excitation energy. Furthermore, these and new
calculations predict the existence of states at slightly higher energy that
could facilitate isomer de-excitation studies.Comment: published in PRL 110, 12250
Electron Cooling Experiments in CSR
The six species heavy ion beam was accumulated with the help of electron
cooling in the main ring of Cooler Storage Ring of Heavy Ion Research Facility
in Lanzhou(HIRFL-CSR), the ion beam accumulation dependence on the parameters
of cooler was investigated experimentally. The 400MeV/u 12C6+ and 200MeV/u
129Xe54+ was stored and cooled in the experimental ring CSRe, the cooling force
was measured in different condition.Comment: 5 pages 11 figure
Heart and systemic effects of statin pretreatment in a rat model of abdominal sepsis. Assessment by Tc99m-sestamibi biodistribition
PURPOSE:
To evaluate the heart and the Tc-99m-sestamibi biodistribution after statin pretreatment in a rat model of abdominal sepsis.
METHODS:
Twenty-four Wistar rats were randomly distributed into four groups (n=6 per group): 1) sepsis with simvastatin treatment, 2) sepsis with vehicle, 3) sham control with simvastatin and 4) sham control with vehicle. 24 hours after cecal ligation and puncture rats received 1.0MBq of Tc-99m-sestamibi i.v. 30min after, animals were euthanized for ex-vivo tissue counting and myocardium histological analysis.
RESULTS:
Myocardial histologic alterations were not detected 24 hours post-sepsis. There was significantly increased cardiac Tc-99m-sestamibi activity in the sepsis group with simvastatin treatment (1.90.3%ID/g, p<0.001) in comparison to the sepsis group+vehicle (1.00.2% ID/g), control sham group+ simvastatin (1.20.3% ID/g) and control sham group (1.30.2% ID/g). Significant Tc-99m-sestamibi activity in liver, kidney and lungs was also detected in the sepsis group treated with simvastatinin comparison to the other groups.
CONCLUSIONS:
Statin treatment altered the biodistribution of Tc-99m-sestamibi with increased cardiac and solid organ activity in rats with abdominal sepsis, while no impact on controls. Increased myocardial tracer activity may be a result of a possible protection effect due to increased tissue perfusion mediated by statins
Isotope Shift in the Dielectronic Recombination of Three-electron \u3csup\u3eA\u3c/sup\u3eNdâ”â·âș
Isotope shifts in dielectronic recombination spectra were studied for Li-like ANd57+ ions with A = 142 and A = 150. From the displacement of resonance positions energy shifts ÎŽE142 150(2s-2p1/2) = 40.2(3)(6) meV [(stat)(sys)] and ÎŽE142 150(2s - 2p3/2) = 42.3(12)(20)meV of 2s - 2pj transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of 142 150ÎŽâš r2â© = -1.36(1)(3) fm2. The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size
Reporting conditionals with modals
Conditionals and modals work in tandem in some instances of practical reasoning, or decision making. Consider the following example (from Kratzer 2012):
a. I want to become a mayor.
b. (q) I will become a mayor only if (p) I go to the pub.
c. Therefore, I should go to the pub.
Given what the cogniser wants (a) and the relevant circumstances (b), the conclusion that the cogniser goes to the pub comes out as necessary. Hence, the presence of the necessity modal should in (c). Indeed, given the context of (a), the necessity modal in (c) is simply a reflection of the necessity of p for q, which is overtly represented by the use of the âonly if p, qâ construction. This chapter looks into whether indirect reports of conditionals â in particular, indirect reports which involve the use of a modal verb â are sensitive to the necessity of p for q in cases where necessity is not overtly represented in a conditional, as in âif p, qâ formulations.
We report on two online experiments into the relation between (i) perceived necessity or sufficiency of the truth of a conditional antecedent for the truth of the consequent, and (ii) the formulation of an indirect report of a conditional with necessity or possibility modals (have to, should, could). In Experiment 1, the ânecessity/sufficiency of p for qâ variable was manipulated by contextually altering the number of alternative antecedents (e.g. Cummins et al. 1991; Thompson 1994; Politzer 2003). It was found that modals used in indirect reports of âif p, qâ conditionals co-vary with the number of alternative antecedents in predictable ways. This suggests that modals used in indirect reports of âif p, qâ conditionals may be a diagnostic for biconditional versus material interpretations of conditionals. The aim of Experiment 2 was to find out whether the results of Experiment 1 could be replicated in contexts which lower/eliminate the believability of the conditionals. It was found that manipulating the believability variable has no reliable effect on the results
Indirect Reports in Modern Eastern Armenian
In this work we consider the distribution of complementizers in Modern
Eastern Armenian. There are two complementizers: wor and tâe. They
both introduce complement clauses, but tâe also expresses a dubitative
value, implying that the speaker has doubts on the content following the
complementizer. Moreover, tâe, when embedded under verbs of saying,
shifts the anchoring of indexicals, moving the anchor from the speaker
â better called utterer â to the subject of the saying predicate. On the
basis of this and further evidence coming from the analysis of sequence
of tense and if-clauses, we will argue that the position of tâe in the left
periphery of the clause occupies a high position in the syntactic hierarchy.
The aim of this work is on one hand, a better understanding of indirect
reports and their syntax and, on the other, a more precise characterization
of indexicals across languages
Long-term TNT and DNT contamination: 1-D modeling of natural attenuation in the vadose zone: case study, Portugal
The vadose zone of a trinitrotoluene (TNT) and dinitrotoluene (DNT) contaminated site was investigated to assess the mobility of those explosives under natural conditions. Located in the left margin of the River Tejo Basin, Portugal, the site is located on unconsolidated sediments. Wastewaters associated with the 50-year explosives production were disposed in excavated ponds, from where water would infiltrate and pollute the unsaturated and saturated parts of the local aquifers. Two boreholes were drilled to 9 m depth in such a former waste pond to investigate the contaminant's fate in the vadose zone. Sediment samples were taken every 1-2 m for analysis of the polynitroaromatics (p-NACs) and organic volatile compounds, pH, organic carbon content, cation exchange capacity and grain size analysis. The main contaminant was TNT representing >70 % of the total p-NACs concentration that peaked approximately 7 mg/kg in one borehole, even if the median in both boreholes was of similar to 1 mg/kg. DNT was 4-30 % of the total p-NACs and nitrotoluene (NT), up to 5 %. No other (volatile) organic compound was detected. The predominance of TNT as the main contaminant implies that any natural mass reduction has been inefficient to clean the site. Several 1-D model simulations of p-NACs cleaning of the vadose zone under natural conditions indicated that the most probable scenario of combined advection and partitioning will only remove TNT after 10's of years, whereas DNT and NT will hardly be removed. Such low concentrations and long times for the p-NACs removal, suggest that by now those compounds have been washed-out to a level below standard limits
Vapor-Phase Oxidation of Benzyl Alcohol Using Manganese Oxide Octahedral Molecular Sieves (OMS-2)
Vapor-phase selective oxidation of benzyl alcohol has been accomplished using cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) catalysts. A conversion of 92% and a selectivity to benzaldehyde of 99% were achieved using OMS-2. The role played by the oxidant in this system was probed by studying the reaction in the absence of oxidant. The natures of framework transformations occurring during the oxidation reaction were fully studied using temperature-programmed techniques, as well as in situ X-ray diffraction under different atmospheres
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