140,215 research outputs found
Two loop Kahler potential in beta-deformed N=4 SYM theory
In N=2 superconformal field theories the Kahler potential is known to be tree
level exact. The beta-deformation of N=4 SU(N) SYM reduces the amount of
supersymmetry to N=1, allowing for non-trivial, superconformal loop corrections
to the Kahler potential. We analyse the two-loop corrections on the Coulomb
branch for a complex deformation. For an arbitrary chiral field in the Cartan
subalgebra we reduce the problem of computing the two-loop Kahler potential to
that of diagonalising the mass matrix, we then present the result in a
manifestly superconformal form. The mass matrix diagonalisation is performed
for the case of the chiral background that induces the breaking pattern SU(N)
-> SU(N-2)*U(1)^2. Then, for the gauge group SU(3), the Kahler potential is
explicitly computed to the two-loop order.Comment: 24 pages, 1 figure, version published in JHE
The potential for super-Nyquist asteroseismology with TESS
The perfect 30-min cadence of the full-frame images from the Transiting
Exoplanet Survey Satellite (TESS) will impose a hard Nyquist limit of 24
d ( Hz). This will be problematic for asteroseismology
of stars with oscillation frequencies at or around that Nyquist limit, which
will have insurmountable Nyquist ambiguities. TESS does offer some observing
slots at shorter cadences, but these will be limited in number and competitive,
while the full frame images will be the main data product for many types of
variable stars. We show that the Nyquist ambiguities can be alleviated if, when
TESS resumes observations after a downlink, integrations are not resumed at
perfect cadence with those before the downlink. The time spent idling before
integrations are resumed need only be around five minutes for satisfactory
results, and observing time can be recouped from the downlink event if the
telescope does not wait for a return to perfect cadence before resuming
integrations. The importance of imperfect cadence after downlink is discussed
in light of phase coverage of transit events.Comment: 7 pages; 9 figures, all of which use colour but have been checked for
readability under grey-scale printing; 2 small tables; accepted for
publication in MNRA
The Legal Status of Gibraltar: Whose Rock is it Anyway?
This Note argues that the right to self-determination, as expressed in Resolution 1514, empowers the people of Gibraltar with the right to determine their own destiny. Part I discusses the factual and legal background of the dispute over sovereignty of both the City of Gibraltar, as well as the isthmus connecting the city to Spain. Part II explains the British, Spanish, and Gibraltarian claims to the territory, analyzing the relevant U.N. resolutions, agreements and legislation that have defined the respective rights of the three parties. Part III argues that Gibraltar has the right to self-determination and that Great Britain should no longer represent Gibraltar in negotiations with Spain. This Note concludes that, in accord with Resolution 1514, Gibraltar has the right to self-determination, and the Spanish claim to territorial integrity does not supersede this right
Stabilizer States as a Basis for Density Matrices
We show that the space of density matrices for n-qubit states, considered as
a (2^n)^2 dimensional real vector space, has a basis consisting of density
matrices of stabilizer states. We describe an application of this result to
automated verification of quantum protocols
The Legal Status of Gibraltar: Whose Rock is it Anyway?
This Note argues that the right to self-determination, as expressed in Resolution 1514, empowers the people of Gibraltar with the right to determine their own destiny. Part I discusses the factual and legal background of the dispute over sovereignty of both the City of Gibraltar, as well as the isthmus connecting the city to Spain. Part II explains the British, Spanish, and Gibraltarian claims to the territory, analyzing the relevant U.N. resolutions, agreements and legislation that have defined the respective rights of the three parties. Part III argues that Gibraltar has the right to self-determination and that Great Britain should no longer represent Gibraltar in negotiations with Spain. This Note concludes that, in accord with Resolution 1514, Gibraltar has the right to self-determination, and the Spanish claim to territorial integrity does not supersede this right
Specific isoforms of translation initiation factor 4GI show differences in translational activity
The eukaryotic initiation factor (eIF) 4GI gene locus (eIF4GI) contains three identified promoters, generating alternately spliced mRNAs, yielding a total of five eIF4GI protein isoforms. Although eIF4GI plays a critical role in mRNA recruitment to the ribosomes, little is known about the functions of the different isoforms, their partner binding capacities, or the role of the homolog, eIF4GII, in translation initiation. To directly address this, we have used short interfering RNAs (siRNAs) expressed from DNA vectors to silence the expression of eIF4GI in HeLa cells. Here we show that reduced levels of specific mRNA and eIF4GI isoforms in HeLa cells promoted aberrant morphology and a partial inhibition of translation. The latter reflected dephosphorylation of 4E-BP1 and decreased eIF4F complex levels, with no change in eIF2 alpha phosphorylation. Expression of siRNA-resistant Myc-tagged eIF4GI isoforms has allowed us to show that the different isoforms exhibit significant differences in their ability to restore translation rates. Here we quantify the efficiency of eIF4GI promoter usage in mammalian cells and demonstrate that even though the longest isoform of eIF4GI (eIF4GIf) was relatively poorly expressed when reintroduced, it was more efficient at promoting the translation of cellular mRNAs than the more highly expressed shorter isoforms used in previous functional studies
Kidney surveillance in the spotlight: contrast-induced acute kidney injury illuminated
Acute kidney injury comprises a heterogeneous group of conditions characterized by a sudden decrease in renal function over hours to days. Contrast-induced acute kidney injury (CI-AKI) is caused by radiographic contrast agents used in diagnostic imaging. In the current issue of the JCI, Lau et al. use a mouse model of CI-AKI to study the role of resident and infiltrating phagocytes, recruited leukocytes, and tubular cells in the immune surveillance response to contrast agents. This study has the potential to provide innovative therapies for human CI-AKI
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