1,806 research outputs found
On the global symmetries of 6D superconformal field theories
We study global symmetry groups of six-dimensional superconformal field
theories (SCFTs). In the Coulomb branch we use field theoretical arguments to
predict an upper bound for the global symmetry of the SCFT. We then analyze
global symmetry groups of F-theory constructions of SCFTs with a
one-dimensional Coulomb branch. While in the vast majority of cases, all of the
global symmetries allowed by our Coulomb branch analysis can be realized in
F-theory, in a handful of cases we find that F-theory models fail to realize
the full symmetry of the theory on the Coulomb branch. In one particularly
mysterious case, F-theory models realize several distinct maximal subgroups of
the predicted group, but not the predicted group itself.Comment: 47 pages; v2: typos corrected, added the case su(6)* to the analysis
of section 5 and section 6.1. v3: references added, minor changes, published
versio
Shutting Down the Offense: Why the Supreme Court Should Designate the NFL a Single Entity for Antitrust Purposes
Conifold Transitions in M-theory on Calabi-Yau Fourfolds with Background Fluxes
We consider topology changing transitions for M-theory compactifications on
Calabi-Yau fourfolds with background G-flux. The local geometry of the
transition is generically a genus g curve of conifold singularities, which
engineers a 3d gauge theory with four supercharges, near the intersection of
Coulomb and Higgs branches. We identify a set of canonical, minimal flux quanta
which solve the local quantization condition on G for a given geometry,
including new solutions in which the flux is neither of horizontal nor vertical
type. A local analysis of the flux superpotential shows that the potential has
flat directions for a subset of these fluxes and the topologically different
phases can be dynamically connected. For special geometries and background
configurations, the local transitions extend to extremal transitions between
global fourfold compactifications with flux. By a circle decompactification the
M-theory analysis identifies consistent flux configurations in four-dimensional
F-theory compactifications and flat directions in the deformation space of
branes with bundles.Comment: 93 pages; v2: minor changes and references adde
Mesons and Flavor on the Conifold
We explore the addition of fundamental matter to the Klebanov-Witten field
theory. We add probe D7-branes to the theory obtained from placing
D3-branes at the tip of the conifold and compute the meson spectrum for the
scalar mesons. In the UV limit of massless quarks we find the exact dimensions
of the associated operators, which exhibit a simple scaling in the large-charge
limit. For the case of massive quarks we compute the spectrum of scalar mesons
numerically.Comment: 19 pages, 3 figures, v2: typos fixe
Observations on Food Consumption and Preference in Four Alaskan Mammals
Contains report of a study made during Oct.-Nov. in Wisconsin where animals captured two months earlier in Alaska, were maintained in captivity. Alaskan ground squirrels, Dawson red-back voles, Alaskan collared lemmings and pikas were fed both fresh and dry food and their water intake, caloric intake and food preferences studied. There was little agreement among the various species in food preference; caloric intake was in general greater per weight unit in small than in large animals. Simple food consumption values are shown to be a fairly reliable measure of metabolic requirements and output in wild animals. The lemmings' catholic taste is noted as a factor favorable for survival in rigorous environment. For other papers from this study see Arctic Bibliography No. 26500-26501
Non-continuous and variable rate processes: Optimisation for energy use
The need to develop new and improved ways of reducing energy use and increasing energy intensity in industrial processes is currently a major issue in New Zealand. Little attention has been given to optimisation of non-continuous processes in the past, due to their complexity, yet they remain an essential and often energy intensive component of many industrial sites. Novel models based on pinch analysis that aid in minimising utility usage have been constructed here through the adaptation of proven continuous techniques. The knowledge has been integrated into a user friendly software package, and allows the optimisation of processes under variable operating rates and batch conditions. An example problem demonstrates the improvements in energy use that can be gained when using these techniques to analyse non-continuous data. A comparison with results achieved using a pseudo-continuous method show that the method described can provide simultaneous reductions in capital and operating costs
Utility of patient-derived lymphoblastoid cell lines as an ex vivo capecitabine sensitivity prediction model for breast cancer patients.
Capecitabine is commonly used in treating breast cancer; however, therapeutic response varies among patients and there is no clinically validated model to predict individual outcomes. Here, we investigated whether drug sensitivity quantified in ex vivo patients' blood-derived cell lines can predict response to capecitabine in vivo. Lymphoblastoid cell lines (LCLs) were established from a cohort of metastatic breast cancer patients (n = 53) who were prospectively monitored during treatment with single agent capecitabine at 2000 mg/m2/day. LCLs were treated with increasing concentrations of 5'-DFUR, a major capecitabine metabolite, to assess patients' ex vivo sensitivity to this drug. Subsequently, ex vivo phenotype was compared to observed patient disease response and drug induced-toxicities. We acquired an independent cohort of breast cancer cell lines and LCLs derived from the same donors from ATCC, compared their sensitivity to 5'-DFUR. As seen in the patient population, we observed large inter-individual variability in response to 5'-DFUR treatment in patient-derived LCLs. Patients whose LCLs were more sensitive to 5'-DFUR had a significantly longer median progression free survival (9-month vs 6-month, log rank p-value = 0.017). In addition, this significant positive correlation for 5'-DFUR sensitivity was replicated in an independent cohort of 8 breast cancer cell lines and LCLs derived from the same donor. Our data suggests that at least a portion of the individual sensitivity to capecitabine is shared between germline tissue and tumor tissue. It also supports the utility of patient-derived LCLs as a predictive model for capecitabine treatment efficacy in breast cancer patients
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