34 research outputs found
Nonuniversal prefactors in correlation functions of 1D quantum liquids
We develop a general approach to calculating "nonuniversal" prefactors in
static and dynamic correlation functions of 1D quantum liquids at zero
temperature, by relating them to the finite size scaling of certain matrix
elements (form factors). This represents a new, powerful tool for extracting
data valid in the thermodynamic limit from finite-size effects. As the main
application, we consider weakly interacting spinless fermions with an arbitrary
pair interaction potential, for which we perturbatively calculate certain
prefactors in static and dynamic correlation functions. We also
non-perturbatively evaluate prefactors of the long-distance behavior of
correlation functions for the exactly solvable Lieb-Liniger model of 1D bosons
Interaction quenches in the 1D Bose gas
The non-equilibrium dynamics of integrable systems are special: there is
substantial evidence that after a quantum quench they do not thermalize but
their asymptotic steady state can be described by a Generalized Gibbs Ensemble
(GGE). Most of the studies on the GGE so far have focused on models that can be
mapped to quadratic systems while analytic treatment in non-quadratic systems
remained elusive. We obtain results on interaction quenches in a non-quadratic
continuum system, the 1D Bose gas described by the integrable Lieb-Liniger
model. We compute local correlators for a non-interacting initial state and
arbitrary final interactions as well as two-point functions for quenches to the
Tonks-Girardeau regime. We show that in the long time limit integrability leads
to significant deviations from the predictions of the grand canonical ensemble.Comment: Supersedes arXiv:1204.3889. 4+ pages + Supplementary Materia
Drive in Peace
In this paper, in order to implement a computer vision-based recognition system of driving fatigue. In addition to detecting human face in different light sources and the background conditions, and tracking eyes state combined with fuzzy logic to determine whether the driver of the physiological phenomenon of fatigue from face of detection. Driving fatigue recognition has been valued highly in recent years by many scholars and used extensively in various fields, for example, driver activity tracking, driver visual attention monitoring, and in-car camera systems.In this paper, we use the Windows operating system as the development environment, and utilize PC as the hardware platform. First, the system uses a camera to obtain the frame with a human face to detect, and then uses the frame to set the appropriate skin color scope to find face. Next, we find and mark out the eyes and the lips from the selected face area. Finally, we combine the image processing of eyes features with fuzzy logic to determine the driver's fatigue level, and make the graphical man-machine interface with MiniGUI for users to operate.Along with that we are using Arduino Uno microcontroller which is connected to MQ2-smoke sensor through which we can detect smoke which appears through issue in the car system. The results of experiment show that we achieve this system on PC platform successfully
Celecoxib alleviates tamoxifen-instigated angiogenic effects by ROS-dependent VEGF/VEGFR2 autocrine signaling
Background: Tamoxifen (TAM) is widely used in the chemotherapy of breast cancer and as a preventive agent against recurrence after surgery. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy. Celecoxib (CXB), a selective COX-2 inhibitor, suppresses VEGF gene expression by targeting the VEGF promoter responsible for its inhibitory effect. For this study, we had selected CXB as non-steroidal anti-inflammatory drug in combination with TAM for suppressing VEGF expression and simultaneously reducing doses of both the drugs. Methods: The effects of CXB combined with TAM were examined in two human breast cancer cell lines in culture, MCF7 and MDA-MB-231. Assays of proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution and receptor signaling were performed. Results: Here, we elucidated how the combination of TAM and CXB at nontoxic doses exerts anti-angiogenic effects by specifically targeting VEGF/VEGFR2 autocrine signaling through ROS generation. At the molecular level, TAM-CXB suppresses VHL-mediated HIF-1α activation, responsible for expression of COX-2, MMP-2 and VEGF. Besides low VEGF levels, TAM-CXB also suppresses VEGFR2 expression, confirmed through quantifying secreted VEGF levels, luciferase and RT-PCR studies. Interestingly, we observed that TAM-CXB was effective in blocking VEGFR2 promoter induced expression and further 2 fold decrease in VEGF levels was observed in combination than TAM alone in both cell lines. Secondly, TAM-CXB regulated VEGFR2 inhibits Src expression, responsible for tumor progression and metastasis. FACS and in vivo enzymatic studies showed significant increase in the reactive oxygen species upon TAM-CXB treatment. Conclusions: Taken together, our experimental results indicate that this additive combination shows promising outcome in anti-metastatic and apoptotic studies. In a line, our preclinical studies evidenced that this additive combination of TAM and CXB is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF and VEGFR2. This ingenious combination might be a better tailored clinical regimen than TAM alone for breast cancer treatment
Exact prefactors in static and dynamic correlation functions of 1D quantum integrable models: applications to the Calogero-Sutherland, Lieb-Liniger and XXZ models
In this article we demonstrate a recently developed technique which addresses
the problem of obtaining non-universal prefactors of the correlation functions
of 1D systems at zero temperature. Our approach combines the effective field
theory description of generic 1D quantum liquids with the finite size scaling
of form factors (matrix elements) which are obtained using microscopic
techniques developed in the context of integrable models. We thus establish
exact analytic forms for the prefactors of the long-distance behavior of equal
time correlation functions as well as prefactors of singularities of dynamic
response functions. In this article our focus is on three specific integrable
models: the Calogero-Sutherland, Lieb-Liniger, and XXZ models.Comment: 95 pages and 8 figure