234 research outputs found
Flavor constraints on two-Higgs-doublet models with general diagonal Yukawa couplings
We consider constraints from flavor physics on two-Higgs-doublet models
(2HDM) with general, flavor-diagonal, Yukawa couplings. Analyzing the charged
Higgs contribution to different observables, we find that
transitions and restrict the coupling of the
top quark (corresponding to in models with a symmetry) to
for GeV. Stringent constraints from
meson decays are obtained also on the other third generation couplings
and , but with stronger dependence on
. For the second generation, we obtain constraints on combinations of
, , and from leptonic and
decays. The limits on the general couplings are translated to the common
2HDM types I -- IV with a symmetry, and presented on the
plane. The flavor constraints are most excluding in the
type II model which lacks a decoupling limit in . We obtain a lower
limit GeV in models of type II and III, while no lower
bound on is found for types I and IV.Comment: 24 pages, 11 figures. v2: Minor changes to text and numerics, results
and conclusions unchanged. References adde
ELVIS - ELectromagnetic Vector Information Sensor
The ELVIS instrument was recently proposed by the authors for the Indian
Chandrayaan-1 mission to the Moon and is presently under consideration by the
Indian Space Research Organisation (ISRO). The scientific objective of ELVIS is
to explore the electromagnetic environment of the moon. ELVIS samples the full
three-dimensional (3D) electric field vector, E(x,t), up to 18 MHz, with
selective Nyqvist frequency bandwidths down to 5 kHz, and one component of the
magnetic field vector, B(x,t), from a few Hz up to 100 kHz.As a transient
detector, ELVIS is capable of detecting pulses with a minimum pulse width of 5
ns. The instrument comprises three orthogonal electric dipole antennas, one
magnetic search coil antenna and a four-channel digital sampling system,
utilising flexible digital down conversion and filtering together with
state-of-the-art onboard digital signal processing.Comment: 8 pages, 3 figures. Submitted to the DGLR Int. Symposium "To Moon and
Beyond", Bremen, Germany, 2005. Companion paper to arXiv:astro-ph/050921
Prospects for Lunar Satellite Detection of Radio Pulses from Ultrahigh Energy Neutrinos Interacting with the Moon
The Moon provides a huge effective detector volume for ultrahigh energy
cosmic neutrinos, which generate coherent radio pulses in the lunar surface
layer due to the Askaryan effect. In light of presently considered lunar
missions, we propose radio measurements from a Moon-orbiting satellite. First
systematic Monte Carlo simulations demonstrate the detectability of Askaryan
pulses from neutrinos with energies above 10^{20} eV, i.e. near and above the
interesting GZK limit, at the very low fluxes predicted in different scenarios.Comment: RevTeX (4 pages, 2 figures). v2 includes updated results and extended
discussio
Properties and biases of the global heat flow compilation
Geothermal heat flow is inferred from the gradient of temperature values in boreholes or short-penetration probe measurements. Such measurements are expensive and logistically challenging in remote locations and, therefore, often targeted to regions of economic interest. As a result, measurements are not distributed evenly. Some tectonic, geologic and even topographic settings are overrepresented in global heat flow compilations; other settings are underrepresented or completely missing. These limitations in representation have implications for empirical heat flow models that use catalogue data to assign heat flow by the similarity of observables. In this contribution, we analyse the sampling bias in the Global Heat Flow database of the International Heat Flow Commission; the most recent and extensive heat flow catalogue, and discuss the implications for accurate prediction and global appraisals. We also suggest correction weights to reduce the bias when the catalogue is used for empirical modelling. From comparison with auxiliary variables, we find that each of the following settings is highly overrepresented for heat flow measurements; continental crust, sedimentary rocks, volcanic rocks, and Phanerozoic regions with hydrocarbon exploration. Oceanic crust, cratons, and metamorphic rocks are underrepresented. The findings also suggest a general tendency to measure heat flow in areas where the values are elevated; however, this conclusion depends on which auxiliary variable is under consideration to determine the settings. We anticipate that using our correction weights to balance disproportional representation will improve empirical heat flow models for remote regions and assist in the ongoing assessment of the Global Heat Flow database
Fee Arrangements and Fee Shifting: Lessons From the Experience in Ontario
About one-third of oestrogen receptor alpha-positive breast cancer patients treated with tamoxifen relapse. Here we identify the nuclear receptor retinoic acid receptor alpha as a marker of tamoxifen resistance. Using quantitative mass spectrometry-based proteomics, we show that retinoic acid receptor alpha protein networks and levels differ in a tamoxifen-sensitive (MCF7) and a tamoxifen-resistant (LCC2) cell line. High intratumoural retinoic acid receptor alpha protein levels also correlate with reduced relapse-free survival in oestrogen receptor alpha-positive breast cancer patients treated with adjuvant tamoxifen solely. A similar retinoic acid receptor alpha expression pattern is seen in a comparable independent patient cohort. An oestrogen receptor alpha and retinoic acid receptor alpha ligand screening reveals that tamoxifen-resistant LCC2 cells have increased sensitivity to retinoic acid receptor alpha ligands and are less sensitive to oestrogen receptor alpha ligands compared with MCF7 cells. Our data indicate that retinoic acid receptor alpha may be a novel therapeutic target and a predictive factor for oestrogen receptor alpha-positive breast cancer patients treated with adjuvant tamoxifen
New angles on top quark decay to a charged Higgs
To properly discover a charged Higgs Boson () requires its spin and
couplings to be determined. We investigate how to utilize \ttbar spin
correlations to analyze the couplings in the decay . Within the framework of a general Two-Higgs-Doublet Model, we
obtain results on the spin analyzing coefficients for this decay and study in
detail its spin phenomenology, focusing on the limits of large and small values
for . Using a Monte Carlo approach to simulate full hadron-level
events, we evaluate systematically how the decay
mode can be used for spin analysis. The most promising observables are obtained
from azimuthal angle correlations in the transverse rest frames of
. This method is particularly useful for determining the coupling
structure of in the large limit, where differences from the
SM are most significant.Comment: 28 pages, 13 figures. Uses JHEP forma
Intratumor Heterogeneity of the Estrogen Receptor and the Long-term Risk of Fatal Breast Cancer.
Background:Breast cancer patients with estrogen receptor (ER)-positive disease have a continuous long-term risk for fatal breast cancer, but the biological factors influencing this risk are unknown. We aimed to determine whether high intratumor heterogeneity of ER predicts an increased long-term risk (25 years) of fatal breast cancer. Methods:The STO-3 trial enrolled 1780 postmenopausal lymph node-negative breast cancer patients randomly assigned to receive adjuvant tamoxifen vs not. The fraction of cancer cells for each ER intensity level was scored by breast cancer pathologists, and intratumor heterogeneity of ER was calculated using Rao's quadratic entropy and categorized into high and low heterogeneity using a predefined cutoff at the second tertile (67%). Long-term breast cancer-specific survival analyses by intra-tumor heterogeneity of ER were performed using Kaplan-Meier and multivariable Cox proportional hazard modeling adjusting for patient and tumor characteristics. Results:A statistically significant difference in long-term survival by high vs low intratumor heterogeneity of ER was seen for all ER-positive patients (P < .001) and for patients with luminal A subtype tumors (P = .01). In multivariable analyses, patients with high intratumor heterogeneity of ER had a twofold increased long-term risk as compared with patients with low intratumor heterogeneity (ER-positive: hazard ratio [HR] = 1.98, 95% confidence interval [CI] = 1.31 to 3.00; luminal A subtype tumors: HR = 2.43, 95% CI = 1.18 to 4.99). Conclusions:Patients with high intratumor heterogeneity of ER had an increased long-term risk of fatal breast cancer. Interestingly, a similar long-term risk increase was seen in patients with luminal A subtype tumors. Our findings suggest that intratumor heterogeneity of ER is an independent long-term prognosticator with potential to change clinical management, especially for patients with luminal A tumors
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