115 research outputs found
Gravity duals of half-BPS Wilson loops
We explicitly construct the fully back-reacted half-BPS solutions in Type IIB
supergravity which are dual to Wilson loops with 16 supersymmetries in
super Yang-Mills. In a first part, we use the methods of a
companion paper to derive the exact general solution of the half-BPS equations
on the space , with isometry group
in terms of two locally harmonic functions
on a Riemann surface with boundary. These solutions, generally, have
varying dilaton and axion, and non-vanishing 3-form fluxes. In a second part,
we impose regularity and topology conditions. These non-singular solutions may
be parametrized by a genus hyperelliptic surface , all of
whose branch points lie on the real line. Each genus solution has only a
single asymptotic region, but exhibits homology
3-spheres, and an extra homology 5-spheres, carrying respectively RR 3-form
and RR 5-form charges. For genus 0, we recover with 3 free
parameters, while for genus , the solution has free
parameters. The genus 1 case is studied in detail. Numerical analysis is used
to show that the solutions are regular throughout the parameter space.
Collapse of a branch cut on subtending either a homology 3-sphere or a
homology 5-sphere is non-singular and yields the genus solution. This
behavior is precisely expected of a proper dual to a Wilson loop in gauge
theory.Comment: 62 pages, LaTeX, 6 figures, v2: minor change
Exact Half-BPS Flux Solutions in M-theory III: Existence and rigidity of global solutions asymptotic to AdS4 x S7
The BPS equations in M-theory for solutions with 16 residual supersymmetries,
symmetry, and asymptotics,
were reduced in [arXiv:0806.0605] to a linear first order partial differential
equation on a Riemann surface with boundary, subject to a non-trivial quadratic
constraint. In the present paper, suitable regularity and boundary conditions
are imposed for the existence of global solutions. We seek regular solutions
with multiple distinct asymptotic regions, but find that,
remarkably, such solutions invariably reduce to multiple covers of the M-Janus
solution found by the authors in [arXiv:0904.3313], suggesting rigidity of the
half-BPS M-Janus solution. In particular, we prove analytically that no other
smooth deformations away from the M-Janus solution exist, as such deformations
invariably violate the quadratic constraint. These rigidity results are
contrasted to the existence of half-BPS solutions with non-trivial 4-form
fluxes and charges asymptotic to . The results are related to
the possibility of M2-branes to end on M5-branes, but the impossibility of
M5-branes to end on M2-branes, and to the non-existence of half-BPS solutions
with simultaneous and asymptotic regions.Comment: 52 pages, 2 figures, pdf-latex. Minor change
A global map to aid the identification and screening of critical habitat for marine industries
Marine industries face a number of risks that necessitate careful analysis prior to making decisions on the siting of operations and facilities. An important emerging regulatory framework on environmental sustainability for business operations is the International Finance Corporationâs Performance Standard 6 (IFC PS6). Within PS6, identification of biodiversity significance is articulated through the concept of âCritical Habitatâ, a definition developed by the IFC and detailed through criteria aligned with those that support internationally accepted biodiversity designations. No publicly available tools have been developed in either the marine or terrestrial realm to assess the likelihood of sites or operations being located within PS6-defined Critical Habitat. This paper presents a starting point towards filling this gap in the form of a preliminary global map that classifies more than 13 million km2 of marine and coastal areas of importance for biodiversity (protected areas, Key Biodiversity Areas [KBA], sea turtle nesting sites, cold- and warm-water corals, seamounts, seagrass beds, mangroves, saltmarshes, hydrothermal vents and cold seeps) based on their overlap with Critical Habitat criteria, as defined by IFC. In total, 5798Ă103 km2 (1.6%) of the analysis area (global ocean plus coastal land strip) were classed as Likely Critical Habitat, and 7526Ă103 km2 (2.1%) as Potential Critical Habitat; the remainder (96.3%) were Unclassified. The latter was primarily due to the paucity of biodiversity data in marine areas beyond national jurisdiction and/or in deep waters, and the comparatively fewer protected areas and KBAs in these regions. Globally, protected areas constituted 65.9% of the combined Likely and Potential Critical Habitat extent, and KBAs 29.3%, not accounting for the overlap between these two features. Relative Critical Habitat extent in Exclusive Economic Zones varied dramatically between countries. This work is likely to be of particular use for industries operating in the marine and coastal realms as an early screening aid prior to in situ Critical Habitat assessment; to financial institutions making investment decisions; and to those wishing to implement good practice policies relevant to biodiversity management. Supplementary material (available online) includes other global datasets considered, documentation and justification of biodiversity feature classification, detail of IFC PS6 criteria/scenarios, and coverage calculations
Exact half-BPS Type IIB interface solutions I: Local solution and supersymmetric Janus
The complete Type IIB supergravity solutions with 16 supersymmetries are
obtained on the manifold with
symmetry in terms of two holomorphic
functions on a Riemann surface , which generally has a boundary. This
is achieved by reducing the BPS equations using the above symmetry
requirements, proving that all solutions of the BPS equations solve the full
Type IIB supergravity field equations, mapping the BPS equations onto a new
integrable system akin to the Liouville and Sine-Gordon theories, and mapping
this integrable system to a linear equation which can be solved exactly.
Amongst the infinite class of solutions, a non-singular Janus solution is
identified which provides the AdS/CFT dual of the maximally supersymmetric
Yang-Mills interface theory discovered recently. The construction of general
classes of globally non-singular solutions, including fully back-reacted and supersymmetric Janus doped with D5 and/or NS5 branes, is
deferred to a companion paper.Comment: LaTeX, 69 pages, 3 figures, v2: references adde
Human enteroids: Preclinical models of non-inflammatory diarrhea
Researchers need an available and easy-to-use model of the human intestine to better understand human intestinal physiology and pathophysiology of diseases, and to offer an enhanced platform for developing drug therapy. Our work employs human enteroids derived from each of the major intestinal sections to advance understanding of several diarrheal diseases, including those caused by cholera, rotavirus and enterohemorrhagic Escherichia coli. An enteroid bank is being established to facilitate comparison of segmental, developmental, and regulatory differences in transport proteins that can influence therapy efficacy. Basic characterization of major ion transport protein expression, localization and function in the human enteroid model sets the stage to study the effects of enteric infection at the transport level, as well as to monitor potential responses to pharmacological intervention
Long term outcomes of biomaterial-mediated repair of focal cartilage defects in a large animal model
The repair of focal cartilage defects remains one of the foremost issues in the field of orthopaedics. Chondral defects may arise from a variety of joint pathologies and left untreated, will likely progress to osteoarthritis. Current repair techniques, such as microfracture, result in short-term clinical improvements but have poor long-term outcomes. Emerging scaffold-based repair strategies have reported superior outcomes compared to microfracture and motivate the development of new biomaterials for this purpose. In this study, unique composite implants consisting of a base porous reinforcing component (woven poly(Δ-caprolactone)) infiltrated with 1 of 2 hydrogels (self-assembling peptide or thermo-gelling hyaluronan) or bone marrow aspirate were evaluated. The objective was to evaluate cartilage repair with composite scaffold treatment compared to the current standard of care (microfracture) in a translationally relevant large animal model, the Yucatan minipig. While many cartilage-repair studies have shown some success in vivo, most are short term and not clinically relevant. Informed by promising 6-week findings, a 12-month study was carried out and those results are presented here. To aid in comparisons across platforms, several structural and functionally relevant outcome measures were performed. Despite positive early findings, the long-term results indicated less than optimal structural and mechanical results with respect to cartilage repair, with all treatment groups performing worse than the standard of care. This study is important in that it brings much needed attention to the importance of performing translationally relevant long-term studies in an appropriate animal model when developing new clinical cartilage repair approaches
Janus solutions in M-theory
We present a one-parameter deformation of the AdS_{4} x S^{7} vacuum, which
is a regular solution in M-theory, invariant under SO(2,2) x SO(4) x SO(4), and
which preserves 16 supersymmetries. The solution corresponds to a holographic
realization of a Janus-like interface/defect theory, despite the absence of a
dilaton in M-theory. The 2+1-dimensional CFT dual results from the maximally
symmetric CFT through the insertion of a dimension 2 operator which is
localized along a 1+1-dimensional linear interface/defect, thereby partially
breaking the superconformal symmetry. The solution admits a regular ABJM
reduction to a quotient solution which is invariant under SO(2,2) x SO(4) x
U(1)^2, preserves 12 supersymmetries, and provides a Janus-like
interface/defect solution in ABJM theory.Comment: 20 pages, 2 figures, pdflate
Recommended from our members
Track A Basic Science
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd
Enhancing effects of anti-CD40 treatment on the immune response of SCID-bovine mice to Trypanosoma congolense infection
African trypansosomes are tsetse-transmitted parasites of chief importance in causing disease in livestock in regions of sub-Saharan Africa. Previous studies have demonstrated that certain breeds of cattle are relatively resistant to infection with trypanosomes, and others are more susceptible. Because of its extracellular location, the humoral branch of the immune system dominates the response against Trypanosoma congolense. In the following study, we describe the humoral immune response generated against T. congolense in SCID mice reconstituted with a bovine immune system (SCID-bo). SCID-bo mice infected with T. congolense were treated with an agonistic anti-CD40 antibody and monitored for the development of parasitemia and survival. Anti-CD40 antibody administration resulted in enhanced survival compared with mice receiving the isotype control. In addition, we demonstrate that the majority of bovine IgM+ B cells in SCID-bo mice expresses CD5, consistent with a neonatal phenotype. It is interesting that the percentage of bovine CD5+ B cells in the peripheral blood of infected SCID-bo mice was increased following anti-CD40 treatment. Immunohistochemical staining also indicated increased numbers of Ig+ cells in the spleens of anti-CD40-treated mice. Consistent with previous studies demonstrating high IL-10 production during high parasitemia levels in mice and cattle, abundant IL-10 mRNA message was detected in the spleens and peripheral blood of T. congolense-infected SCID-bo mice during periods of high parasitemia. In addition, although detected in plasma when parasites were absent or low in number, bovine antibody was undetectable during high parasitemia. However, Berenil treatment allowed for the detection of VSG-specific IgG 14 days postinfection in T. congolense-infected SCID-bo mice. Overall, the data indicate that survival of trypanosome-infected SCID-bo mice is prolonged when an agonistic antibody against bovine CD40 (ILA156) is administered. Thus, stimulation of B cells and/or other cell types through CD40 afforded SCID-bo mice a slight degree of protection during T. congolense infection
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