174 research outputs found
Differential display identifies overexpression of the USP36 gene, encoding a deubiquitinating enzyme, in ovarian cancer
Objectives. To find potential diagnostic markers or therapeutic targets, we used differential display technique to identify genes that are over or under expressed in human ovarian cancer. Methods. Genes were initially identified by differential display between two human ovarian surface epithelium cultures and two ovarian cancer cell lines, A2780 and Caov-3. Genes were validated by relative quantitative RT-PCR and RNA in situ hybridization. Results. Twenty-eight non-redundant sequences were expressed differentially in the normal ovarian epithelium and ovarian cancer cell lines. Seven of the 28 sequences showed differential expression between normal ovary and ovarian cancer tissue by RT-PCR. USP36 was over-expressed in ovarian cancer cell lines and tissues by RT-PCR and RNA in situ hybridization. Northern blot analysis and RT-PCR revealed two transcripts for USP36 in ovarian tissue. The major transcript was more specific for ovarian cancer and was detected by RT-PCR in 9/9 ovarian cancer tissues, 3/3 cancerous ascites, 5/14 (36%) sera from patients with ovarian cancer, and 0/7 sera from women without ovarian cancer. Conclusion. USP36 is overexpressed in ovarian cancer compared to normal ovary and its transcripts were identified in ascites and serum of ovarian cancer patients
Prying into the intimate secrets of animal lives; software beyond hardware for comprehensive annotation in âDaily Diaryâ tags
Smart tags attached to freely-roaming animals recording multiple parameters at infra-second rates are becoming commonplace, and are transforming our understanding of the way wild animals operate. However, interpretation of such data is complex and currently limits the ability of biologists to realise the value of their recorded information. This work presents a single program, FRAMEWORK 4, that uses a particular sensor constellation described in the?Daily Diary? tag (recording tri-axial acceleration, tri-axial magnetic field intensity, pressure and e.g. temperature and light intensity) to determine the 4 key elements considered pivotal within the conception of the tag. These are; animal trajectory, behaviour, energy expenditure and quantification of the environment in which the animal operates. The program takes the original data recorded by the Daily Dairy and transforms it into dead-reckoned movements,template-matched behaviours, dynamic body acceleration-derived energetics and positionlinked environmental data before outputting it all into a single file. Biologists are thus left with a single data set where animal actions and environmental conditions can be linked across time and space.Fil: Walker, James S.. Swansea University. College Of Sciences; Reino UnidoFil: Jones, Mark W.. Swansea University. College Of Sciences; Reino UnidoFil: Laramee, Robert S.. Swansea University. College Of Sciences; Reino UnidoFil: Holton, Mark D.. Swansea University; Reino UnidoFil: Shepard, Emily L. C.. Swansea University. College Of Sciences; Reino UnidoFil: Williams, Hannah J.. Swansea University. College Of Sciences; Reino UnidoFil: Scantlebury, D. Michael. The Queens University Of Belfast; IrlandaFil: Marks, Nikki, J.. The Queens University Of Belfast; IrlandaFil: Magowan, Elizabeth A.. The Queens University Of Belfast; IrlandaFil: Maguire, Iain E.. The Queens University Of Belfast; IrlandaFil: Grundy, Ed. Swansea University. College Of Sciences; Reino UnidoFil: Di Virgilio, Agustina Soledad. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Patagonia Norte. Instituto de InvestigaciĂłn En Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Wilson, Rory P.. Swansea University. College Of Sciences; Reino Unid
Recursive Calculation of One-Loop QCD Integral Coefficients
We present a new procedure using on-shell recursion to determine coefficients
of integral functions appearing in one-loop scattering amplitudes of gauge
theories, including QCD. With this procedure, coefficients of integrals,
including bubbles and triangles, can be determined without resorting to
integration. We give criteria for avoiding spurious singularities and boundary
terms that would invalidate the recursion. As an example where the criteria are
satisfied, we obtain all cut-constructible contributions to the one-loop
n-gluon scattering amplitude, A_n^{oneloop}(...--+++...), with split-helicity
from an N=1 chiral multiplet and from a complex scalar. Using the
supersymmetric decomposition, these are ingredients in the construction of QCD
amplitudes with the same helicities. This method requires prior knowledge of
amplitudes with sufficiently large numbers of legs as input. In many cases,
these are already known in compact forms from the unitarity method.Comment: 36 pages; v2 clarification added and typos fixed, v3 typos fixe
MHV-Vertices for Gravity Amplitudes
We obtain a CSW-style formalism for calculating graviton scattering
amplitudes and prove its validity through the use of a special type of
BCFW-like parameter shift. The procedure is illustrated with explicit examples.Comment: 21 pages, minor typos corrected, proof added in section
Orbifolding the Twistor String
The D-instanton expansion of the topological B-model on the supermanifold
CP(3|4) reproduces the perturbative expansion of N=4 Super Yang-Mills theory.
In this paper we consider orbifolds in the fermionic directions of CP(3|4).
This operation breaks the SU(4) R-symmetry group, reducing the amount of
supersymmetry of the gauge theory. As specific examples we take N=1 and N=2
orbifolds and obtain the corresponding superconformal quiver theories. We
discuss the D1 instanton expansion in this context and explicitly compute some
amplitudes.Comment: 24 pages, 8 figures; v2: minor correction
Multigluon tree amplitudes with a pair of massive fermions
We consider the calculation of n-point multigluon tree amplitudes with a pair
of massive fermions in QCD. We give the explicit transformation rules of this
kind of massive fermion-pair amplitudes with respect to different reference
momenta and check the correctness of them by SUSY Ward identities. Using these
rules and onshell BCFW recursion relation, we calculate the analytic results of
several n-point multigluon amplitudes.Comment: 15page
MHV Rules for Higgs Plus Multi-Gluon Amplitudes
We use tree-level perturbation theory to show how non-supersymmetric one-loop
scattering amplitudes for a Higgs boson plus an arbitrary number of partons can
be constructed, in the limit of a heavy top quark, from a generalization of the
scalar graph approach of Cachazo, Svrcek and Witten. The Higgs boson couples to
gluons through a top quark loop which generates, for large top mass, a
dimension-5 operator H tr G^2. This effective interaction leads to amplitudes
which cannot be described by the standard MHV rules; for example, amplitudes
where all of the gluons have positive helicity. We split the effective
interaction into the sum of two terms, one holomorphic (selfdual) and one
anti-holomorphic (anti-selfdual). The holomorphic interactions give a new set
of MHV vertices -- identical in form to those of pure gauge theory, except for
momentum conservation -- that can be combined with pure gauge theory MHV
vertices to produce a tower of amplitudes with more than two negative
helicities. Similarly, the anti-holomorphic interactions give anti-MHV vertices
that can be combined with pure gauge theory anti-MHV vertices to produce a
tower of amplitudes with more than two positive helicities. A Higgs boson
amplitude is the sum of one MHV-tower amplitude and one anti-MHV-tower
amplitude. We present all MHV-tower amplitudes with up to four
negative-helicity gluons and any number of positive-helicity gluons (NNMHV).
These rules reproduce all of the available analytic formulae for Higgs +
n-gluon scattering (n<=5) at tree level, in some cases yielding considerably
shorter expressions.Comment: 34 pages, 8 figures; v2, references correcte
The ecology of exercise: mechanisms underlying Individual variation in behavior, activity, and performance: an introduction to symposium
Wild animals often engage in intense physical activity while performing tasks vital for their survival and reproduction associated with foraging, avoiding predators, fighting, providing parental care, and migrating. In this theme issue we consider how viewing these tasks as âexerciseââanalogous to that performed by human athletesâmay help provide insight into the mechanisms underlying individual variation in these types of behaviors and the importance of physical activity in an ecological context. In this article and throughout this issue, we focus on four key questions relevant to the study of behavioral ecology that may be addressed by studying wild animal behavior from the perspective of exercise physiology: (1) How hard do individual animals work in response to ecological (or evolutionary) demands?; (2) Do lab-based studies of activity provide good models for understanding activity in free-living animals and individual variation in traits?; (3) Can animals work too hard during âroutineâ activities?; and (4) Can paradigms of âexerciseâ and âtrainingâ be applied to free-living animals? Attempts to address these issues are currently being facilitated by rapid technological developments associated with physiological measurements and the remote tracking of wild animals, to provide mechanistic insights into the behavior of free-ranging animals at spatial and temporal scales that were previously impossible. We further suggest that viewing the behaviors of non-human animals in terms of the physical exercise performed will allow us to fully take advantage of these technological advances, draw from knowledge and conceptual frameworks already in use by human exercise physiologists, and identify key traits that constrain performance and generate variation in performance among individuals. It is our hope that, by highlighting mechanisms of behavior and performance, the articles in this issue will spur on further synergies between physiologists and ecologists, to take advantage of emerging cross-disciplinary perspectives and technologies
Solution to the Ward Identities for Superamplitudes
Supersymmetry and R-symmetry Ward identities relate on-shell amplitudes in a
supersymmetric field theory. We solve these Ward identities for (Next-to)^K MHV
amplitudes of the maximally supersymmetric N=4 and N=8 theories. The resulting
superamplitude is written in a new, manifestly supersymmetric and R-invariant
form: it is expressed as a sum of very simple SUSY and SU(N)_R-invariant
Grassmann polynomials, each multiplied by a "basis amplitude". For (Next-to)^K
MHV n-point superamplitudes the number of basis amplitudes is equal to the
dimension of the irreducible representation of SU(n-4) corresponding to the
rectangular Young diagram with N columns and K rows. The linearly independent
amplitudes in this algebraic basis may still be functionally related by
permutation of momenta. We show how cyclic and reflection symmetries can be
used to obtain a smaller functional basis of color-ordered single-trace
amplitudes in N=4 gauge theory. We also analyze the more significant reduction
that occurs in N=8 supergravity because gravity amplitudes are not ordered. All
results are valid at both tree and loop level.Comment: 29 pages, published versio
Minimally helicity violating, maximally simple scalar amplitudes in N=4 SYM
In planar N=4 SYM we study a particular class of helicity preserving
amplitudes. These are scalar amplitudes whose flavor configuration is chosen in
such a way that only a limited number of diagrams is allowed, which exhibit an
iterative structure. For such amplitudes we evaluate the tree level and
one-loop contributions, providing a general formula valid for any number of
particles. The ratio between the one-loop and tree level results is a simple
combination of dual conformally invariant box functions with at most two
massive legs. Along with the MHV and NMHV series, this constitutes the third
known infinite sequence of one-loop amplitudes in N=4 SYM.Comment: 22 pages, 7 figures, published versio
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