3,006 research outputs found
Cosmic acceleration from asymmetric branes
We consider a single 3-brane sitting in between two different five
dimensional spacetimes. On each side of the brane, the bulk is a solution to
Gauss-Bonnet gravity, although the bare cosmological constant, funda mental
Planck scale, and Gauss-Bonnet coupling can differ. This asymmetry leads to
weighted junction conditions across the brane and interesting brane cosmology.
We focus on two special cases: a generalized Randall-Sundrum model without any
Gauss-Bonnet terms, and a stringy model, without any bare cosmological
constants, and positive Gauss-Bonnet coupling. Even though we assume there is
no vacuum energy on the brane, we find late time de Sitter cosmologies can
occur. Remarkably, in certain parameter regions, this acceleration is preceded
by a period of matter/radiation domination, with , all the
way back to nucleosynthesis.Comment: Version appearing in CQ
High-resolution isotope-shift spectroscopy of Cd I
We present absolute frequency measurements of the 1P1←1S0 (229nm) and 3P1←1S0 (326nm) transitions for all naturally occurring isotopes of cadmium. The isotope shifts and hyperfine intervals of the fermionic isotopes are determined with an accuracy of 3.3MHz. We find that quantum interference in the laser-induced fluorescence spectra of the 1P1←1S0 transition causes an error of up to 29(5)MHz in determining the hyperfine splitting, when not accounted for with an appropriate model. Using a King-plot analysis, we extract the field- and mass-shift parameters and determine nuclear charge radius differences for the fermions. The lifetime of the 1P1 state is determined to be 1.60(5)ns by measuring the natural linewidth of the 1P1←1S0 transition. These results resolve significant discrepancies among previous measurements
Black Holes in Ho\v{r}ava Gravity with Higher Derivative Magnetic Terms
We consider Horava gravity coupled to Maxwell and higher derivative magnetic
terms. We construct static spherically symmetric black hole solutions in the
low-energy approximation. We calculate the horizon locations and temperatures
in the near-extremal limit, for asymptotically flat and (anti-)de Sitter
spaces. We also construct a detailed balanced version of the theory, for which
we find projectable and non-projectable, non-perturbative solutions.Comment: 17 pages. v2: Up to date with published version; some minor remarks
and more reference
Radiation Campaign of HPK Prototype LGAD sensors for the High-Granularity Timing Detector (HGTD)
We report on the results of a radiation campaign with neutrons and protons of
Low Gain Avalanche Detectors (LGAD) produced by Hamamatsu (HPK) as prototypes
for the High-Granularity Timing Detector (HGTD) in ATLAS. Sensors with an
active thickness of 50~m were irradiated in steps of roughly 2 up
to a fluence of . As a function of the
fluence, the collected charge and time resolution of the irradiated sensors
will be reported for operation at
Prevención y gestión de residuos sólidos urbanos en el Valle de Mazatepec
En este periodo se trabajó fuertemente en la comunidad de Ahuisculco en colaboración con la asociación Selva Negra cuyos actores principales fueron: Lupita Zavala y René Velázquez, en donde se presentó la iniciativa de proyecto que habla sobre la gestión de residuos valorizables, el cual tuvo buen recibimiento por la comunidad y al presentarse al ejido se pudo conseguir una bodega que se planea utilizar a manera de centro comunitario de acopio de residuos sólidos urbanos; además de ello se consolidó una relación con la primaria Rafael Ramírez para la impartición de talleres y pláticas de educación ambiental, generando un plan de actividades autorizado por el Director Luis Cruz Alvarado y apoyado por la asociación Selva Negra. Este programa se plantea aplicar en el periodo de primavera 2022. A su vez, se trabajó en la comunidad de San Isidro Mazatepec donde se impartieron, diseñaron y gestionaron talleres de educación ambiental con los alumnos del COBAEJ con temas de compostaje, aprovechamiento de residuos, huertos en casa y colorantes naturales. También se organizó la rifa de un kit de separación de residuos orgánicos entre las comunidades de San Isidro y La Villita, con el objetivo de juntar fondos para poder remodelar e instalar puntos limpios en San Isidro y comenzar con la construcción de un punto de acopio de residuos en La Villita.ITESO, A.C
Antitumor activity of colloidal silver on MCF-7 human breast cancer cells
<p>Abstract</p> <p>Background</p> <p>Colloidal silver has been used as an antimicrobial and disinfectant agent. However, there is scarce information on its antitumor potential. The aim of this study was to determine if colloidal silver had cytotoxic effects on MCF-7 breast cancer cells and its mechanism of cell death.</p> <p>Methods</p> <p>MCF-7 breast cancer cells were treated with colloidal silver (ranged from 1.75 to 17.5 ng/mL) for 5 h at 37°C and 5% CO<sub>2 </sub>atmosphere. Cell Viability was evaluated by trypan blue exclusion method and the mechanism of cell death through detection of mono-oligonucleosomes using an ELISA kit and TUNEL assay. The production of NO, LDH, and Gpx, SOD, CAT, and Total antioxidant activities were evaluated by colorimetric assays.</p> <p>Results</p> <p>Colloidal silver had dose-dependent cytotoxic effect in MCF-7 breast cancer cells through induction of apoptosis, shown an LD<sub>50 </sub>(3.5 ng/mL) and LD<sub>100 </sub>(14 ng/mL) (*P < 0.05), significantly decreased LDH (*P < 0.05) and significantly increased SOD (*P < 0.05) activities. However, the NO production, and Gpx, CAT, and Total antioxidant activities were not affected in MCF-7 breast cancer cells. PBMC were not altered by colloidal silver.</p> <p>Conclusions</p> <p>The present results showed that colloidal silver might be a potential alternative agent for human breast cancer therapy.</p
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
- …