3,614 research outputs found
Global Conformal Invariance in D-dimensions and Logarithmic Correlation Functions
We define transformation of multiplets of fields (Jordan cells) under the
D-dimensional conformal group, and calculate two and three point functions of
fields, which show logarithmic behaviour. We also show how by a formal
differentiation procedure, one can obtain n-point function of logarithmic field
theory from those of ordinary conformal field theory.Comment: 9 pages, LaTeX, some misprints are corrected, to be published in
Phys. Lett.
On Optimal and Fair Service Allocation in Mobile Cloud Computing
This paper studies the optimal and fair service allocation for a variety of
mobile applications (single or group and collaborative mobile applications) in
mobile cloud computing. We exploit the observation that using tiered clouds,
i.e. clouds at multiple levels (local and public) can increase the performance
and scalability of mobile applications. We proposed a novel framework to model
mobile applications as a location-time workflows (LTW) of tasks; here users
mobility patterns are translated to mobile service usage patterns. We show that
an optimal mapping of LTWs to tiered cloud resources considering multiple QoS
goals such application delay, device power consumption and user cost/price is
an NP-hard problem for both single and group-based applications. We propose an
efficient heuristic algorithm called MuSIC that is able to perform well (73% of
optimal, 30% better than simple strategies), and scale well to a large number
of users while ensuring high mobile application QoS. We evaluate MuSIC and the
2-tier mobile cloud approach via implementation (on real world clouds) and
extensive simulations using rich mobile applications like intensive signal
processing, video streaming and multimedia file sharing applications. Our
experimental and simulation results indicate that MuSIC supports scalable
operation (100+ concurrent users executing complex workflows) while improving
QoS. We observe about 25% lower delays and power (under fixed price
constraints) and about 35% decrease in price (considering fixed delay) in
comparison to only using the public cloud. Our studies also show that MuSIC
performs quite well under different mobility patterns, e.g. random waypoint and
Manhattan models
A Logarithmic Conformal Field Theory Solution For Two Dimensional Magnetohydrodynamics In Presence of The Alf'ven Effect
When Alf`ven effect is peresent in magnetohydrodynamics one is naturally lead
to consider conformal field theories, which have logarithmic terms in their
correlation functions. We discuss the implications of such logarithmic terms
and find a unique conformal field theory with centeral charge
, within the border of the minimal series, which satisfies
all the constraints. The energy espectrum is found to be \newline .Comment: Latex, 9 page
On conformal Jordan cells of finite and infinite rank
This work concerns in part the construction of conformal Jordan cells of
infinite rank and their reductions to conformal Jordan cells of finite rank. It
is also discussed how a procedure similar to Lie algebra contractions may
reduce a conformal Jordan cell of finite rank to one of lower rank. A conformal
Jordan cell of rank one corresponds to a primary field. This offers a picture
in which any finite conformal Jordan cell of a given conformal weight may be
obtained from a universal covering cell of the same weight but infinite rank.Comment: 9 pages, LaTeX, v2: typo corrected, comments added, version to be
publishe
Spin-independent origin of the strongly enhanced effective mass in a dilute 2D electron system
We have accurately measured the effective mass in a dilute two-dimensional
electron system in silicon by analyzing temperature dependence of the
Shubnikov-de Haas oscillations in the low-temperature limit. A sharp increase
of the effective mass with decreasing electron density has been observed. Using
tilted magnetic fields, we have found that the enhanced effective mass is
independent of the degree of spin polarization, which points to a
spin-independent origin of the mass enhancement and is in contradiction with
existing theories
Coherent back-scattering near the two-dimensional metal-insulator transition
We have studied corrections to conductivity due to the coherent
backscattering in low-disordered two-dimensional electron systems in silicon
for a range of electron densities including the vicinity of the metal-insulator
transition, where the dramatic increase of the spin susceptibility has been
observed earlier. We show that the corrections, which exist deeper in the
metallic phase, weaken upon approaching to the transition and practically
vanish at the critical density, thus suggesting that the localization is
suppressed near and at the transition even in zero field.Comment: to appear in PR
Targeting tumor multicellular aggregation through IGPR-1 inhibits colon cancer growth and improves chemotherapy
Adhesion to extracellular matrix (ECM) is crucially important for survival of normal epithelial cells as detachment from ECM triggers specific apoptosis known as anoikis. As tumor cells lose the requirement for anchorage to ECM, they rely on cell-cell adhesion 'multicellular aggregation' for survival. Multicellular aggregation of tumor cells also significantly determines the sensitivity of tumor cells to the cytotoxic effects of chemotherapeutics. In this report, we demonstrate that expression of immunoglobulin containing and proline-rich receptor-1 (IGPR-1) is upregulated in human primary colon cancer. Our study demonstrates that IGPR-1 promotes tumor multicellular aggregation, and interfering with its adhesive function inhibits multicellular aggregation and, increases cell death. IGPR-1 supports colon carcinoma tumor xenograft growth in mouse, and inhibiting its activity by shRNA or blocking antibody inhibits tumor growth. More importantly, IGPR-1 regulates sensitivity of tumor cells to the chemotherapeutic agent, doxorubicin/adriamycin by a mechanism that involves doxorubicin-induced AKT activation and phosphorylation of IGPR-1 at Ser220. Our findings offer novel insight into IGPR-1's role in colorectal tumor growth, tumor chemosensitivity, and as a possible novel anti-cancer target.Grant support from: R01 CA175382/CA/NCI NIH HHS/United States, R21 CA191970/CA/NCI NIH HHS/United States, and R21 CA193958/CA/NCI NIH HHS/United State
Epidemiology and short-term mortality in traumatic patients admitted to Shariati Hospital in Iran between 2012 and 2013
Purpose Trauma is an inevitable part of the health burden in every country. Both the preventive and rehabilitative aspects of traumatic injuries are expensive. Since most of the injuries happen in low- and middle-income developing countries, a judicious allocation of the limited resources to the most cost-efficient strategies is necessary. The present study was designed to report the causes of trauma, injured body regions, trauma severity scores and the one year survival rate of a randomly selected sample of trauma patients in a major referral hospital in Tehran, Iran. Methods We chose and analyzed a random subgroup of traumatic patients admitted during the one-year period of May 2012 to May 2013 to Shariati Hospital, a major University Teaching Hospital in Tehran, Iran. Patients who stayed at the hospital for less than 24 h were excluded. In total, 73 traumatic patients were registered. The mean age was (40.19 ± 20.34) years and 67.1 of them were male. Results In general, the most common cause of injury was falls (47.9), followed by road traffic crashes (RTCs, 40.8). Assault and exposure to inanimate mechanical forces each were only associated with 5.6 of all injuries. The only cause of injury in ages of more than 65 years was fall. The most common cause of injury in ages between 15 and 45 years was RTCs. During the study, two deaths occurred: one was at ICU and the other was at home. The most commonly injured body region was the head (23.8), followed by the elbow and forearm (19), hip and thigh (15.9), and multiple body regions (14.3). The mean abbreviated injury score was 2.23 ± 1.02; injury severity index was 7.26 ± 7.06; and revised trauma score was 7.84, calculated for 38 patients. Conclusion Prevention strategy of traumatic injury should focus on falls and RTCs, which are respectively the most common cause of trauma in older aged people and young males. © 2015 Production and hosting by Elsevier B.V
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