1,332 research outputs found
Septicaemia with Dysgonic Fermenter -2 (DF-2) bacterium in a compromised host
Contains fulltext :
4451.pdf (publisher's version ) (Open Access
One-loop N-point equivalence among negative-dimensional, Mellin-Barnes and Feynman parametrization approaches to Feynman integrals
We show that at one-loop order, negative-dimensional, Mellin-Barnes' (MB) and
Feynman parametrization (FP) approaches to Feynman loop integrals calculations
are equivalent. Starting with a generating functional, for two and then for
-point scalar integrals we show how to reobtain MB results, using
negative-dimensional and FP techniques. The point result is valid for
different masses, arbitrary exponents of propagators and dimension.Comment: 11 pages, LaTeX. To be published in J.Phys.
Parity-violating 3-jet observables for massive quarks to order alphas^2 in e+e- annihilation
In this talk we discuss the calculation of the QCD corrections to
parity-violating 3-jet observables in e^+e^- collisions, keeping the full quark
mass dependence.Comment: 5 pages, Talk given at International Euroconference in Quantum
Chromodynamics: 15 Years of the QCD - Montpellier Conference (QCD 00),
Montpellier, France, 6-12 Jul 200
Precise determination of the Wtb couplings at LHC
Top pair production at LHC is the ideal place to search for nonstandard Wtb
couplings in t -> W b -> l nu b decays. The lb forward-backward asymmetry in
the W rest frame is very sensitive to sigma_{mu nu} couplings, and can spot
one-loop QCD corrections to the decay vertex with more than 5 sigma statistical
significance. We discuss the potential of this asymmetry to signal nonstandard
gamma_mu and sigma_{mu nu} couplings and compare with top-antitop spin
correlation asymmetries, which have a lower sensitivity. We also briefly
summarise the results for Tevatron.Comment: LaTeX, 12 pages, 2 PS figures. One reference added. To be published
in PR
Next-to-Leading Order QCD Corrections to Jet Cross Sections and Jet Rates in Deeply Inelastic Electron Proton Scattering
Jet cross sections in deeply inelastic scattering in the case of transverse
photon exchange for the production of (1+1) and (2+1) jets are calculated in
next-to-leading order QCD (here the `+1' stands for the target remnant jet,
which is included in the jet definition for reasons that will become clear in
the main text). The jet definition scheme is based on a modified JADE cluster
algorithm. The calculation of the (2+1) jet cross section is described in
detail. Results for the virtual corrections as well as for the real initial-
and final state corrections are given explicitly. Numerical results are stated
for jet cross sections as well as for the ratio \sigma_{\mbox{\small (2+1)
jet}}/\sigma_{\mbox{\small tot}} that can be expected at E665 and HERA.
Furthermore the scale ambiguity of the calculated jet cross sections is studied
and different parton density parametrizations are compared.Comment: 40 pages, LBL-34147 (Latex file). (figures available by mail on
request (send e-mail to [email protected]), please include your address
such that it can be used as an address label
Correlates of Toenail Zinc in a Free-Living U.S. Population
No prior studies have reported on dietary correlates of toenail zinc, an easily collected biomarker of zinc status. The study aim was to identify dietary and other factors that influence toenail zinc in a healthy population, in order to understand the usefulness of this biomarker in public health studies. Cross-sectional comparison of toenail zinc with questionnaire measures of demographic and behavioral factors, dietary intake and supplement use. Western Washington State, US. 106 men and 106 women, who are participants in a large cohort study, of whom 66% used multivitamins or individual supplements containing zinc. Increased toenail zinc concentrations were associated with increased dietary zinc intake (adjusted difference in toenail zinc between those in the highest quartile of intake vs. lowest = 11.0 ppm, p for trend = 0.03), with the association primarily among men. Borderline associations of increased toenail zinc were found with decreased vegetable intake (p=0.08) and increased body mass index (p=0.11). Supplemental zinc and intake of phytic acid, alcohol, iron (from food or supplements) did not influence toenail zinc. Toenail zinc concentrations vary with dietary zinc intake, even in a healthy population with presumably little zinc deficiency
Effect of dipole-dipole charge interactions on dust coagulation
This study examines the effect that dipole-dipole charge interactions between
fractal aggregates have on the growth of dust grains. Aggregates in a plasma or
radiative environment will have charge distributed over their extended surface,
which leads to a net dipole moment for the charged grains. A self-consistent
N-body code is used to model the dynamics of interacting charged aggregates.
The aggregates are free to rotate due to collisions and dipole-dipole
electrostatic interactions. These rotations are important in determining the
growth rate and subsequent geometry (fractal dimension) of the grains. In
contrast to previous studies which have only taken charge-dipole interactions
into account, like-charged grains are found to coagulate more efficiently than
neutral grains due to preferential incorporation of small aggregates into
mid-sized aggregate structures. The charged aggregates tend to be more compact
than neutral aggregates, characterized by slightly higher fractal dimensions
Different iron storage strategies among bloom-forming diatoms
Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 115(52), (2018): E12275-E12284. doi: 10.1073/pnas.1805243115.Diatoms are prominent eukaryotic phytoplankton despite being limited by the micronutrient iron in vast expanses of the ocean. As iron inputs are often sporadic, diatoms have evolved mechanisms such as the ability to store iron that enable them to bloom when iron is resupplied and then persist when low iron levels are reinstated. Two iron storage mechanisms have been previously described: the protein ferritin and vacuolar storage. To investigate the ecological role of these mechanisms among diatoms, iron addition and removal incubations were conducted using natural phytoplankton communities from varying iron environments. We show that among the predominant diatoms, Pseudo-nitzschia were favored by iron removal and displayed unique ferritin expression consistent with a long-term storage function. Meanwhile, Chaetoceros and Thalassiosira gene expression aligned with vacuolar storage mechanisms. Pseudo-nitzschia also showed exceptionally high iron storage under steady-state high and low iron conditions, as well as following iron resupply to iron-limited cells. We propose that bloom-forming diatoms use different iron storage mechanisms and that ferritin utilization may provide an advantage in areas of prolonged iron limitation with pulsed iron inputs. As iron distributions and availability change, this speculated ferritin-linked advantage may result in shifts in diatom community composition that can alter marine ecosystems and biogeochemical cycles.We thank the captain and crew of the R/V Melville and the CCGS J. P. Tully as well as the participants of the IRNBRU (MV1405) cruise for the California-based data, particularly K. Ellis [University of North Carolina (UNC)], T. Coale (University of California, San Diego), F. Kuzminov (Rutgers), H. McNair [University of California, Santa Barbara (UCSB)], and J. Jones (UCSB). W. Burns (UNC), S. Haines (UNC), and S. Bargu (Louisiana State University) assisted with sample processing and analysis. This work was funded by the National Science Foundation Grants OCE-1334935 (to A.M.), OCE-1334632 (to B.S.T.), OCE-1333929 (to K.T.), OCE-1334387 (to M.A.B.), OCE-1259776 (to K.W.B), and DGE-1650116 (Graduate Research Fellowship to R.H.L).2019-06-1
Chirality and Symmetry Breaking in a discrete internal Space
In previous papers the permutation group S_4 has been suggested as an
ordering scheme for elementary particles, and the appearance of this finite
symmetry group was taken as indication for the existence of a discrete inner
symmetry space underlying elementary particle interactions. Here it is pointed
out that a more suitable choice than the tetrahedral group S_4 is the
pyritohedral group A_4 x Z_2 because its vibrational spectrum exhibits exactly
the mass multiplet structure of the 3 fermion generations. Furthermore it is
noted that the same structure can also be obtained from a primordial symmetry
breaking S_4 --> A_4. Since A_4 is a chiral group, while S_4 is achiral, an
argument can be given why the chirality of the inner pyritohedral symmetry
leads to parity violation of the weak interactions.Comment: 42 pages, 3 table
Cruciferous vegetable supplementation in a controlled diet study alters the serum peptidome in a GSTM1-genotype dependent manner
<p>Abstract</p> <p>Background</p> <p>Cruciferous vegetable intake is inversely associated with the risk of several cancers. Isothiocyanates (ITC) are hypothesized to be the major bioactive constituents contributing to these cancer-preventive effects. The polymorphic glutathione-<it>S</it>-transferase (GST) gene family encodes several enzymes which catalyze ITC degradation <it>in vivo</it>.</p> <p>Methods</p> <p>We utilized high throughput proteomics methods to examine how human serum peptides (the "peptidome") change in response to cruciferous vegetable feeding in individuals of different <it>GSTM1 </it>genotypes. In two randomized, crossover, controlled feeding studies (EAT and 2EAT) participants consumed a fruit- and vegetable-free basal diet and the basal diet supplemented with cruciferous vegetables. Serum samples collected at the end of the feeding period were fractionated and matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry spectra were obtained. Peak identification/alignment computer algorithms and mixed effects models were used to analyze the data.</p> <p>Results</p> <p>After analysis of spectra from EAT participants, 24 distinct peaks showed statistically significant differences associated with cruciferous vegetable intake. Twenty of these peaks were driven by their <it>GSTM1 </it>genotype (i.e., <it>GSTM1+ </it>or <it>GSTM1- </it>null). When data from EAT and 2EAT participants were compared by joint processing of spectra to align a common set, 6 peaks showed consistent changes in both studies in a genotype-dependent manner. The peaks at 6700 <it>m/z </it>and 9565 <it>m/z </it>were identified as an isoform of transthyretin (TTR) and a fragment of zinc α2-glycoprotein (ZAG), respectively.</p> <p>Conclusions</p> <p>Cruciferous vegetable intake in <it>GSTM1+ </it>individuals led to changes in circulating levels of several peptides/proteins, including TTR and a fragment of ZAG. TTR is a known marker of nutritional status and ZAG is an adipokine that plays a role in lipid mobilization. The results of this study present evidence that the <it>GSTM1</it>-genotype modulates the physiological response to cruciferous vegetable intake.</p
- …