443 research outputs found
Arabidopsis thaliana growth more than defense affects Myzus persicae populations
Aphids and other herbivorous insects are able to travel between plants in their environment. While plants cannot directly choose their consumers, they may stop or mitigate the harmful effects of herbivory using secondary metabolites. A salicylic acid (SA) pathway facilitates defense from biotrophic fungi and some necrotrophic pathogens, while a jasmonic acid (JA) pathway is associated with defense from other necrotrophic pathogens and chewing insects. We investigated the effect of deficiency in SA or JA in Arabidopsis thaliana on plant growth and on herbivory by green peach aphids (Myzus persicae). Three ascensions of A. thaliana were placed in two blocks with three aphids on each individual. The genotypes consisted of a SA-deficient ascension (Sid2), a JA-deficient ascension (Lox2), and a wild type (Col). Wild-type A. thaliana showed significantly greater growth relative to the other ascensions, suggesting better performance, as well as dramatically higher aphid count. Aphid count showed a significant positive correlation with plant growth, suggesting that M. persicae is attracted to signs of growth in A. thaliana, or reproduces more on growing plants. It appears that wild-type plants showed greater growth throughout the experiment, and were thus targeted by the highly responsive M. persicae. This behaviour may be exploited for agricultural purposes; herbivorous insects may be diverted to fast-growing trap crops lacking agricultural value in order to protect primary crops.Faculty Sponsor: Dr. Chad Harve
Postplacental IUCD CuT380A: Acceptability, Effectivity and Side Effects
Objective: To evaluate the acceptability, effectivity and side effects of Postplacental IUCD after vaginal delivery at Dr. Cipto Mangunkusumo Hospital (RSCM) after 6 month of insertion.
Methods: A prospective study was conducted at RSCM Jakarta during the period of August to October 2012. Postplacental IUCD was inserted into the subjects’ uterus until it reached the fundus. Follow up was done at 40-42 days and 6 months after delivery.Â
Results: A total of 234 women were recruited in this study, with 19.2% loss of follow up. No significant difference on subjects characteristics who came and loss of follow up in this study. Expulsion was experienced by 5.1% subjects (total expulsion 4.1% and partial 1%) at the first visit on 40-42 days and 7.5% subjects (total expulsion 0.6% and partial 6.9%) at the second visit, after 6 months. 9.3% subjects had the IUCD removed at the first and second visit. Among all of the subjects who had the IUCD removed by request or had the expulsion, 61% were willing to do reinsertion. The effectivity of IUCD was 100%, with 68.9% subjects was still breastfeeding. The side effects were vaginal discharge (23%), dysmenorrhea (4-21%), and spotting (2-10%).Â
Conclusion: The acceptability and effectivity of postplacental IUCD after 6 months were 86.8% and 100%. Cummulative expulsion rate were 12.6%, and the most common side effects were vaginal discharge, dysmenorea, and spotting.
Keywords: acceptability, effectivity, expulsion rate, IUD, postplacent
Anti-de Sitter Black Holes in Gauged N=8 Supergravity
We present new anti-de Sitter black hole solutions of gauged N=8, SO(8)
supergravity, which is the massless sector of the AdS_4\times S^7 vacuum of
M-theory. By focusing on the U(1)^4 Cartan subgroup, we find non-extremal 1, 2,
3 and 4 charge solutions. In the extremal limit, they may preserve up to 1/2,
1/4, 1/8 and 1/8 of the supersymmetry, respectively. In the limit of vanishing
SO(8) coupling constant, the solutions reduce to the familiar black holes of
the M_4\times T^7 vacuum, but have very different interpretation since there
are no winding states on S^7 and no U-duality. In contrast to the T^7
compactification, moreover, we find no static multi-center solutions. Also in
contrast, the S^7 fields appear "already dualized" so that the 4 charges may be
all electric or all magnetic rather than 2 electric and 2 magnetic. Curiously,
however, the magnetic solutions preserve no supersymmetries. We conjecture that
a subset of the extreme electric black holes preserving 1/2 the supersymmetry
may be identified with the S^7 Kaluza-Klein spectrum, with the non-abelian
SO(8) quantum numbers provided by the fermionic zero modes.Comment: 18 pages, Latex, minor notation improvements and references adde
The Geometry of D=11 Killing Spinors
We propose a way to classify all supersymmetric configurations of D=11
supergravity using the G-structures defined by the Killing spinors. We show
that the most general bosonic geometries admitting a Killing spinor have at
least a local SU(5) or an (Spin(7)\ltimes R^8)x R structure, depending on
whether the Killing vector constructed from the Killing spinor is timelike or
null, respectively. In the former case we determine what kind of local SU(5)
structure is present and show that almost all of the form of the geometry is
determined by the structure. We also deduce what further conditions must be
imposed in order that the equations of motion are satisfied. We illustrate the
formalism with some known solutions and also present some new solutions
including a rotating generalisation of the resolved membrane solutions and
generalisations of the recently constructed D=11 Godel solution.Comment: 36 pages. Typos corrected and discussion on G-structures improved.
Final version to appear in JHE
Intersections of quadrics, moment-angle manifolds, and Hamiltonian-minimal Lagrangian embeddings
We study the topology of Hamiltonian-minimal Lagrangian submanifolds N in C^m
constructed from intersections of real quadrics in a work of the first author.
This construction is linked via an embedding criterion to the well-known
Delzant construction of Hamiltonian toric manifolds. We establish the following
topological properties of N: every N embeds as a submanifold in the
corresponding moment-angle manifold Z, and every N is the total space of two
different fibrations, one over the torus T^{m-n} with fibre a real moment-angle
manifold R, and another over a quotient of R by a finite group with fibre a
torus. These properties are used to produce new examples of Hamiltonian-minimal
Lagrangian submanifolds with quite complicated topology.Comment: 14 pages, published version (minor changes
The linker histone H1.0 generates epigenetic and functional intratumor heterogeneity
Tumors comprise functionally diverse subpopulations of cells with distinct proliferative potential. Here, we show that dynamic epigenetic states defined by the linker histone H1.0 determine which cells within a tumor can sustain the long-term cancer growth. Numerous cancer types exhibit high inter- and intratumor heterogeneity of H1.0, with H1.0 levels correlating with tumor differentiation status, patient survival, and, at the single-cell level, cancer stem cell markers. Silencing of H1.0 promotes maintenance of self-renewing cells by inducing derepression of megabase-sized gene domains harboring downstream effectors of oncogenic pathways. Self-renewing epigenetic states are not stable, and reexpression of H1.0 in subsets of tumor cells establishes transcriptional programs that restrict cancer cells’ long-term proliferative potential and drive their differentiation. Our results uncover epigenetic determinants of tumor-maintaining cells
Bulk vs. Boundary Dynamics in Anti-de Sitter Spacetime
We investigate the details of the bulk-boundary correspondence in Lorentzian
signature anti-de Sitter space. Operators in the boundary theory couple to
sources identified with the boundary values of non-normalizable bulk modes.
Such modes do not fluctuate and provide classical backgrounds on which bulk
excitations propagate. Normalizable modes in the bulk arise as a set of
saddlepoints of the action for a fixed boundary condition. They fluctuate and
describe the Hilbert space of physical states. We provide an explicit, complete
set of both types of modes for free scalar fields in global and Poincar\'e
coordinates. For \ads{3}, the normalizable and non-normalizable modes
originate in the possible representations of the isometry group
\SL_L\times\SL_R for a field of given mass. We discuss the group properties
of mode solutions in both global and Poincar\'e coordinates and their relation
to different expansions of operators on the cylinder and on the plane. Finally,
we discuss the extent to which the boundary theory is a useful description of
the bulk spacetime.Comment: Standard LaTeX, 28 pages, 2 postscript figures. v2: References added.
Substantial revision in section 3 of treatment of global modes;
non-normalizable modes have arbitrary time dependence. Revised discussion of
low-mass modes and puzzle raised re: coupling of the dual boundary operators.
v3: unwanted paragraph removed. v4: Sec. 5.2 correcte
A beginner's introduction to Fukaya categories
The goal of these notes is to give a short introduction to Fukaya categories
and some of their applications. The first half of the text is devoted to a
brief review of Lagrangian Floer (co)homology and product structures. Then we
introduce the Fukaya category (informally and without a lot of the necessary
technical detail), and briefly discuss algebraic concepts such as exact
triangles and generators. Finally, we mention wrapped Fukaya categories and
outline a few applications to symplectic topology, mirror symmetry and
low-dimensional topology. This text is based on a series of lectures given at a
Summer School on Contact and Symplectic Topology at Universit\'e de Nantes in
June 2011.Comment: 42 pages, 13 figure
All solutions of the localization equations for N=2 quantum black hole entropy
We find the most general bosonic solution to the localization equations
describing the contributions to the quantum entropy of supersymmetric black
holes in four-dimensional N=2 supergravity coupled to n_v vector multiplets.
This requires the analysis of the BPS equations of the corresponding off-shell
supergravity (including fluctuations of the auxiliary fields) with AdS2 \times
S2 attractor boundary conditions. Our work completes and extends the results of
arXiv:1012.0265 that were obtained for the vector multiplet sector, to include
the fluctuations of all the fields of the off-shell supergravity. We find that,
when the auxiliary SU(2) gauge field strength vanishes, the most general
supersymmetric configuration preserving four supercharges is labelled by n_v+1
real parameters corresponding to the excitations of the conformal mode of the
graviton and the scalars of the n_v vector multiplets. In the general case, the
localization manifold is labelled by an additional SU(2) triplet of one-forms
and a scalar function.Comment: 27 page
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