290 research outputs found
Constraining Warm Inflation with the Cosmic Microwave Background
We discuss the spectrum of scalar density perturbations from warm inflation
when the friction coefficient in the inflaton equation is dependent on
the inflaton field. The spectral index of scalar fluctuations depends on a new
slow-roll parameter constructed from . A numerical integration of the
perturbation equations is performed for a model of warm inflation and gives a
good fit to the WMAP data for reasonable values of the model's parameters.Comment: 6 pages, 2 figures, RevTeX
Differential cellular interaction of Sutherlandia frutescens extracts on tumorigenic and non-tumorigenic breast cells
Sutherlandia frutescens (SF) is a traditional Africanmedicinal aid employed for the treatment of various ailments
such as inflammation, pulmonary asthma and congestion. The present study was conducted to demonstrate the
differential cellular interaction of aqueous SF extracts in a breast adenocarcinoma epithelial cell line (MCF-7) and
a non-tumorigenic breast cell line (MCF-12A) by means of polarization-optical differential interference contrast
microscopy, crystal violet staining, light microscopy and flowcytometry. Results showed that aqueous SF extracts
induced cell death inMCF-7 andMCF-12A via two types of cell death namely apoptosis and autophagy. Effects on
proliferation and cytotoxicity were investigated by means of crystal violet staining. The latter indicated that, at a
1/10 dilution, the tumorigenic MCF-7 cell line was more prominently affected when compared to the nontumorigenic
MCF-12A cell line. Apoptosis induction was demonstrated by qualitative and quantitative light
microscopy and cell cycle progression studies, while autophagy induction was assessed by an increase inmicrotubule-
associated protein light chain 3 (LC3) levels (a specific marker of autophagy). The MCF-7 tumorigenic
cells, however, were more susceptible to these extracts when compared to the non-tumorigenic MCF-12A
cells. Data obtained contribute towards understanding the differential cellular interaction exerted by aqueous
SF extracts in tumorigenic versus non-tumorigenic breast cells. Results will enable researchers to further study
cell death mechanisms induced by these aqueous extracts and to identify active compounds for evaluation in
anticancer therapy and potential in vivo efficacy.Cancer Association of South Africa (Cape Town, South Africa)http://www.elsevier.com/locate/sajbhb201
Electromagnetic Probes
A review is presented of dilepton and real photon measurements in
relativistic heavy ion collisions over a very broad energy range from the low
energies of the BEVALAC up to the highest energies available at RHIC. The
dileptons cover the invariant mass range \mll = 0 - 2.5 GeV/c, i.e. the
continuum at low and intermediate masses and the light vector mesons, . The review includes also measurements of the light vector mesons
in elementary reactions.Comment: To be published in Landolt-Boernstein Volume 1-23A; 40 pages, 24
figures. Final version updated with small changes to the text, updated
references and updated figure
Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays
By analyzing about 33 data sample collected at and around 3.773
GeV with the BES-II detector at the BEPC collider, we directly measure the
branching fractions for the neutral and charged inclusive semimuonic decays
to be and , and determine the ratio of the two branching
fractions to be
Green function techniques in the treatment of quantum transport at the molecular scale
The theoretical investigation of charge (and spin) transport at nanometer
length scales requires the use of advanced and powerful techniques able to deal
with the dynamical properties of the relevant physical systems, to explicitly
include out-of-equilibrium situations typical for electrical/heat transport as
well as to take into account interaction effects in a systematic way.
Equilibrium Green function techniques and their extension to non-equilibrium
situations via the Keldysh formalism build one of the pillars of current
state-of-the-art approaches to quantum transport which have been implemented in
both model Hamiltonian formulations and first-principle methodologies. We offer
a tutorial overview of the applications of Green functions to deal with some
fundamental aspects of charge transport at the nanoscale, mainly focusing on
applications to model Hamiltonian formulations.Comment: Tutorial review, LaTeX, 129 pages, 41 figures, 300 references,
submitted to Springer series "Lecture Notes in Physics
Measurements of Cabibbo Suppressed Hadronic Decay Fractions of Charmed D0 and D+ Mesons
Using data collected with the BESII detector at storage ring
Beijing Electron Positron Collider, the measurements of relative branching
fractions for seven Cabibbo suppressed hadronic weak decays ,
, and , , and are presented.Comment: 11 pages, 5 figure
Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays
Average charged multiplicities have been measured separately in , and
light quark () events from decays measured in the SLD experiment.
Impact parameters of charged tracks were used to select enriched samples of
and light quark events, and reconstructed charmed mesons were used to select
quark events. We measured the charged multiplicities:
,
, from
which we derived the differences between the total average charged
multiplicities of or quark events and light quark events: and . We compared
these measurements with those at lower center-of-mass energies and with
perturbative QCD predictions. These combined results are in agreement with the
QCD expectations and disfavor the hypothesis of flavor-independent
fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
Measurement of Branching Ratios for Hadronic Decays
In a sample of 58 million events collected with the BES II detector,
the process J/ is observed in five decay channels: , , (with
), (with ) and . From
these signals, we determine ,
, ,
and .Comment: 8 pages, 1 figures and 4 table. Submitted to Phys. Lett.
The effectiveness of flower strips and hedgerows on pest control, pollination services and crop yield: a quantitative synthesis
Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future
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