123 research outputs found
Pseudo-Killing Spinors, Pseudo-supersymmetric p-branes, Bubbling and Less-bubbling AdS Spaces
We consider Einstein gravity coupled to an n-form field strength in D
dimensions. Such a theory cannot be supersymmetrized in general, we
nevertheless propose a pseudo-Killing spinor equation and show that the AdS X
Sphere vacua have the maximum number of pseudo-Killing spinors, and hence are
fully pseudo-supersymmetric. We show that extremal p-branes and their
intersecting configurations preserve fractions of the pseudo-supersymmetry. We
study the integrability condition for general (D,n) and obtain the additional
constraints that are required so that the existence of the pseudo-Killing
spinors implies the Einstein equations of motion. We obtain new
pseudo-supersymmetric bubbling AdS_5 X S^5 spaces that are supported by a
non-self-dual 5-form. This demonstrates that non-supersymmegtric conformal
field theories may also have bubbling states of arbitrary droplets of free
fermions in the phase space. We also obtain an example of less-bubbling AdS
geometry in D=8, whose bubbling effects are severely restricted by the
additional constraint arising from the integrability condition.Comment: typos corrected, extra comments and references added, version
appeared in JHE
On N = 2 Truncations of IIB on T^{1,1}
We study the N=4 gauged supergravity theory which arises from the consistent
truncation of IIB supergravity on the coset T^{1,1}. We analyze three N=2
subsectors and in particular we clarify the relationship between true
superpotentials for gauged supergravity and certain fake superpotentials which
have been widely used in the literature. We derive a superpotential for the
general reduction of type I supergravity on T^{1,1} and this together with a
certain solution generating symmetry is tantamount to a superpotential for the
baryonic branch of the Klebanov-Strassler solution.Comment: 32 pages, v2:references adde
Holographic Renormalization and Stress Tensors in New Massive Gravity
We obtain holographically renormalized boundary stress tensors with the
emphasis on a special point in the parameter space of three dimensional new
massive gravity, using the so-called Fefferman-Graham coordinates with relevant
counter terms. Through the linearized equations of motion with a standard
prescription, we also obtain correlators among these stress tensors. We argue
that the self-consistency of holographic renormalization determines counter
terms up to unphysical ambiguities. Using these renormalized stress tensors in
Fefferman-Graham coordinates, we obtain the central charges of dual CFT, and
mass and angular momentum of some black hole solutions. These results are
consistent with the previous ones obtained by other methods. In this study on
the Fefferman-Graham expansion of new massive gravity, some aspects of higher
curvature gravity are revealed.Comment: Version accepted for publication in JHEP, conclusion revised,
references adde
Non-Abelian T-duality and consistent truncations in type-II supergravity
For a general class of SO(4) symmetric backgrounds in type II-supergravity,
we show that the action of non-Abelian T-duality can be described via
consistent truncation to seven dimensional theories with seemingly massive
modes. As such, any solution to these theories uplifts to both massive type IIA
and IIB supergravities presenting an invertible map between the two. For
supersymmetric backgrounds, we show that for spinors transforming under SO(4)
the non-Abelian T-duality transformation breaks the original supersymmetry by
half. We use these mappings to generate the non-Abelian T-duals of the
maximally supersymmetric pp-wave, the Lin, Lunin, Maldacena geometries and
spacetimes with Lifshitz symmetry.Comment: 41 pages, references added, published versio
Fungal chitinases: diversity, mechanistic properties and biotechnological potential
Chitin derivatives, chitosan and substituted chito-oligosaccharides have a wide spectrum of applications ranging from medicine to cosmetics and dietary supplements. With advancing knowledge about the substrate-binding properties of chitinases, enzyme-based production of these biotechnologically relevant sugars from biological resources is becoming increasingly interesting. Fungi have high numbers of glycoside hydrolase family 18 chitinases with different substrate-binding site architectures. As presented in this review, the large diversity of fungal chitinases is an interesting starting point for protein engineering. In this review, recent data about the architecture of the substrate-binding clefts of fungal chitinases, in connection with their hydrolytic and transglycolytic abilities, and the development of chitinase inhibitors are summarized. Furthermore, the biological functions of chitinases, chitin and chitosan utilization by fungi, and the effects of these aspects on biotechnological applications, including protein overexpression and autolysis during industrial processes, are discussed in this review
The effective action of warped M-theory reductions with higher derivative terms — part I
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