676 research outputs found
A new cell primo-culture method for freshwater benthic diatom communities
A new cell primo-culture method was developed for the benthic diatom community isolated from biofilm sampled in rivers. The approach comprised three steps: (1) scraping biofilm from river pebbles, (2) diatom isolation
from biofilm, and (3) diatom community culture. With a view to designing a method able to stimulate the growth of diatoms, to limit the development of other microorganisms, and to maintain in culture a community similar to the original natural one, different factors were tested in step 3:
cell culture medium (Chu No 10 vs Freshwater “WC” medium modified), cell culture vessel, and time of culture. The results showed that using Chu No 10 medium in an Erlenmeyer flask for cell culture was the optimal method,
producing enough biomass for ecotoxicological tests as well as minimising development of other microorganisms. After 96 h of culture, communities differed from the original communities sampled in the two rivers studied.
Species tolerant of eutrophic or saprobic conditions were favoured during culture. This method of diatom community culture affords the opportunity to assess, in vitro, the effects of different chemicals or effluents (water samples andindustrial effluents) on diatom communities, as well as on diatom cells, from a wide range of perspectives
Single top production in a non-minimal supersymmetric model
We study single top production at the LHC in a SUSY-QCD model with a heavy
Dirac gluino. The presence of a heavy Dirac gluino allows for notable top-up
flavour changing neutral currents. In this scenario, we find that the process
ug->tg gives the largest contribution to single top production via FCNCs at the
LHC. The key features of this signal are that the top quark is produced very
forward and that it is asymmetric to its anti-top counterpart, as the latter
lacks a valence quark.Comment: 9 pages, 4 figures, a background added, references added, minor
revisions, to be published in Phys. Lett.
Supersymmetric Electroweak Corrections to Sbottom Decay into Lighter Stop and Charged Higgs Boson
The Yukawa corrections of order ,
and to the width of sbottom decay into lighter
stop plus charged Higgs boson are calculated in the Minimal Supersymmetric
Standard Model. These corrections depend on the masses of charged Higgs boson
and lighter stop, and the parameters and . For favorable
parameter values, the corrections decrease or increase the decay widths
significantly. Especially for high values of (=30) the corrections
exceed at least 10% for both and decay. But for low
values of (=4,10) the corrections are small and the magnitudes are
less than 10%. The numerical calculations also show that using the running
bottom quark mass which includes the QCD effects and resums all high order
-enhanced effects can improve much the convergence of the
perturbation expansion.Comment: LateX, 27 pages, 13 ps figures. 12 figures updated, a figure and some
references adde
SUSY-electroweak one-loop contributions to Flavour-Changing Higgs-Boson Decays
The SUSY-EW one-loop quantum contributions to flavour-changing MSSM
Higgs-boson decays into and are computed and discussed.
We use the full diagrammatic approach that is valid for all values
and do not rely on the mass-insertion approximation for the characteristic
flavour-changing parameter. We analyze in full detail the dependence of these
flavour-changing partial widths on all the relevant MSSM parameters and also
study the non-decoupling behaviour of these widths with the SUSY mass
parameters. We find that these contributions are sizable as compared to the SM
ones, and together with the SUSY-QCD contributions they can be very efficient
as an indirect method in the future search for Supersymmetry.Comment: LaTeX, 25 pages, 12 figures. Text improved and References added.
Version to appear in Phys.Rev.
Supersymmetric Electroweak Corrections to Heavier Top Squark Decay into Lighter Top Squark and Neutral Higgs Boson
We calculate the Yukawa corrections of order , and
to the widths of the decays in the Minimal Supersymmetric Standard
Model, and perform a detailed numerical analysis. We also compare the results
with the ones presented in an earlier literature, where the SUSY-QCD corrections to the same three decay processes have
been calculated.
Our numerical results show that for the decays , , the Yukawa corrections are
significant in most of the parameter range, which can reach a few ten percent,
and for the decay , the Yukawa corrections are
relatively smaller, which are only a few percent. The numerical calculations
also show that using the running quark masses and the running trilinear
coupling , which include the QCD, SUSY-QCD, SUSY-Electroweak effects and
resume all high order ()-enhanced effects, can vastly improve the
convergence of the perturbation expansion. We also discuss the effects of the
running of the higgsino mass parameter on the corrections, and find that
they are significant, too, especially for large .Comment: 37 pages, 19 eps figure
Flavour Changing Neutral Higgs Boson Decays from Squark - Gluino Loops
We study the flavour changing neutral Higgs boson decays that can be induced
from genuine supersymmetric particles at the one-loop level and within the
context of the Minimal Supersymmetric Standard Model. We consider all the
possible flavour changing decay channels of the three neutral Higgs bosons into
second and third generation quarks, and focus on the Supersymmetric-QCD
corrections from squark-gluino loops which are expected to provide the dominant
contributions. We assume here the more general hypothesis for flavour mixing,
where there is misalignment between the quark and squark sectors, leading to a
flavour non-diagonal squark mass matrix. The form factors involved, and the
corresponding Higgs partial decay widths and branching ratios, are computed
both analytically and numerically, and their behaviour with the parameters of
the Minimal Supersymmetric Standard Model and with the squark mass mixing are
analyzed in full detail. The large rates found, are explained in terms of the
non-decoupling behaviour of these squark-gluino loop corrections in the
scenario with very large supersymmetric mass parameters. Our results show that
if these decays are seen in future colliders they could provide clear indirect
signals of supersymmetry.Comment: 32 Pages and 12 PostScript Level 2 Figures. Some references adde
The Antioxidant Potential of the Mediterranean Diet in Patients at High Cardiovascular Risk: An In-Depth Review of the PREDIMED
Cardiovascular disease (CVD) is the leading global cause of death. Diet is known to be important in the prevention of CVD. The PREDIMED trial tested a relatively low-fat diet versus a high-fat Mediterranean diet (MedDiet) for the primary prevention of CVD. The resulting reduction of the CV composite outcome resulted in a paradigm shift in CV nutrition. Though many dietary factors likely contributed to this effect, this review focuses on the influence of the MedDiet on endogenous antioxidant systems and the effect of dietary polyphenols. Subgroup analysis of the PREDIMED trial revealed increased endogenous antioxidant and decreased pro-oxidant activity in the MedDiet groups. Moreover, higher polyphenol intake was associated with lower incidence of the primary outcome, overall mortality, blood pressure, inflammatory biomarkers, onset of new-onset type 2 diabetes mellitus (T2DM), and obesity. This suggests that polyphenols likely contributed to the lower incidence of the primary event in the MedDiet groups. In this article, we summarize the potential benefits of polyphenols found in the MedDiet, specifically the PREDIMED cohort. We also discuss the need for further research to confirm and expand the findings of the PREDIMED in a non-Mediterranean population and to determine the exact mechanisms of action of polyphenols
The Higgs Boson Production Cross Section as a Precision Observable?
We investigate what can be learned at a linear collider about the sector of
electroweak symmetry breaking from a precise measurement of the Higgs boson
production cross section through the process e+e- -> hZ. We focus on deviations
from the Standard Model arising in its minimal supersymmetric extension. The
analysis is performed within two realistic future scenarios, taking into
account all prospective experimental errors on supersymmetric particle masses
as well as uncertainties from unknown higher order corrections. We find that
information on tan beta and M_A could be obtained from a cross section
measurement with a precision of 0.5 - 1 %. Alternatively, information could be
obtained on the gaugino mass parameters M_2 and mu if they are relatively
small, M_2, mu approximately 200 GeV.Comment: 13 pages, 3 figures. Discussion on experimental errors enlarged,
references added and updated. Version to appear in Phys. Rev.
Single top production at the LHC as a probe of R parity violation
We investigate the potential of the LHC to probe the R parity violating
couplings involving the third generation by considering single top production.
This study is based on particle level event generation for both signal and
background, interfaced to a simplified simulation of the ATLAS detector.Comment: 11 pages, 5 figures, 5 tables (LaTeX, style revtex), few references
adde
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