3,715 research outputs found
A Comparison of Production and Soils in Modified Mixed Prairie Community
This study examined the effects of reseeding a Stipa-Agropyron- Bouteloua community to monocultures of crested wheatgrass (Agropyron cristatum (L.) Geartn.), Russian wild rye grass (Elymus junceus Fisch.), and wheat (Triticum aestivum L.) on above and below ground biomass and indicators of soil quality. Summer fallowed wheat produced 10817 kg ha-1 and 4090 kg ha-1 of above ground below ground biomass respectively whereas the native community produced 3191 kg ha-1 above ground and 13013 kg ha-1 of below ground biomass. However wheat, crested wheatgrass and Russian wildrye grass generally showed a lower biological index, phosphatase and dehydrogenase activity
The propensity of molecules to spatially align in intense light fields
The propensity of molecules to spatially align along the polarization vector
of intense, pulsed light fields is related to readily-accessible parameters
(molecular polarizabilities, moment of inertia, peak intensity of the light and
its pulse duration). Predictions can now be made of which molecules can be
spatially aligned, and under what circumstances, upon irradiation by intense
light. Accounting for both enhanced ionization and hyperpolarizability, it is
shown that {\it all} molecules can be aligned, even those with the smallest
static polarizability, when subjected to the shortest available laser pulses
(of sufficient intensity).Comment: 8 pages, 4 figures, to be submitted to PR
Classification of phase transitions in small systems
We present a classification scheme for phase transitions in finite systems
like atomic and molecular clusters based on the Lee-Yang zeros in the complex
temperature plane. In the limit of infinite particle numbers the scheme reduces
to the Ehrenfest definition of phase transitions and gives the right critical
indices. We apply this classification scheme to Bose-Einstein condensates in a
harmonic trap as an example of a higher order phase transitions in a finite
system and to small Ar clusters.Comment: 12 pages, 4 figures, accepted for publication in Phys. Rev. Let
Irradiation of benzene molecules by ion-induced and light-induced intense fields
Benzene, with its sea of delocalized -electrons in the valence orbitals,
is identified as an example of a class of molecules that enable establishment
of the correspondence between intense ion-induced and laser-light-induced
fields in experiments that probe ionization dynamics in temporal regimes
spanning the attosecond and picosecond ranges.Comment: 4 ps figure
Oscillatory Size-Dependence of the Surface Plasmon Linewidth in Metallic Nanoparticles
We study the linewidth of the surface plasmon resonance in the optical
absorption spectrum of metallic nanoparticles, when the decay into
electron-hole pairs is the dominant channel. Within a semiclassical approach,
we find that the electron-hole density-density correlation oscillates as a
function of the size of the particles, leading to oscillations of the
linewidth. This result is confirmed numerically for alkali and noble metal
particles. While the linewidth can increase strongly, the oscillations persist
when the particles are embedded in a matrix.Comment: RevTeX4, 5 pages, 2 figures, final versio
Ionic and electronic structure of sodium clusters up to N=59
We determined the ionic and electronic structure of sodium clusters with even
electron numbers and 2 to 59 atoms in axially averaged and three-dimensional
density functional calculations. A local, phenomenological pseudopotential that
reproduces important bulk and atomic properties and facilitates structure
calculations has been developed. Photoabsorption spectra have been calculated
for , , and to
. The consistent inclusion of ionic structure considerably
improves agreement with experiment. An icosahedral growth pattern is observed
for to . This finding is supported by
photoabsorption data.Comment: To appear in Phys. Rev. B 62. Version with figures in better quality
can be requested from the author
Chemistry of layered d-metal pnictide oxides and their potential as candidates for new superconductors
Layered d-metal pnictide oxides are a unique class of compounds which
consists of characteristic d-metal pnictide layers and metal oxide layers. More
than 100 of these layered compounds, including the recently discovered Fe-based
superconducting pnictide oxides, can be classified into 9 structure types.
These structure types and the chemical and physical properties of the
characteristic d-metal pnictide layers and metal oxide layers of the layered
d-metal pnictide oxides are reviewed and discussed. Furthermore, possible
approaches to design new superconductors based on these layered d-metal
pnictide oxides are proposed.Comment: 29 pages including 6 tables and 2 figure
Impact of acute coronary syndrome on clinical outcomes after revascularization with the dual-therapy CD34 antibody-covered sirolimus-eluting Combo stent and the sirolimus-eluting Orsiro stent
OBJECTIVES: To compare the efficacy and safety of the dual-therapy CD34 antibody-covered sirolimus-eluting Combo stent (DTS) and the sirolimus-eluting Orsiro stent (O-SES) in patients with and without acute coronary syndrome (ACS) included in the SORT OUT X study.BACKGROUND: The incidence of target lesion failure (TLF) after treatment with modern drug-eluting stents has been reported to be significantly higher in patients with ACS when compared to patients without ACS. Whether the results from the SORT OUT X study apply to patients with and without ACS remains unknown.METHODS: In total, 3146 patients were randomized to stent implantation with DTS (n = 1578; ACS: n = 856) or O-SES (n = 1568; ACS: n = 854). The primary end point, TLF, was a composite of cardiac death, target-lesion myocardial infarction (MI), or target lesion revascularization (TLR) within 1 year.RESULTS: At 1 year, the rate of TLF was higher in the DTS group compared to the O-SES group, both among patients with ACS (6.7% vs. 4.1%; incidence rate ratio: 1.65 [95% confidence interval, CI: 1.08-2.52]) and without ACS (6.0% vs. 3.2%; incidence rate ratio: 1.88 [95% CI: 1.13-3.14]). The differences were mainly explained by higher rates of TLR, whereas rates of cardiac death and target lesion MI did not differ significantly between the two stent groups in patients with or without ACS CONCLUSION: Compared to the O-SES, the DTS was associated with a higher risk of TLF at 12 months in patients with and without ACS. The differences were mainly explained by higher rates of TLR.</p
Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector
The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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