1,692 research outputs found
Wermer examples and currents
In this paper we give the first examples of positive closed currents in
with continuous potentials, vanishing self-intersection, and
which are not laminar. More precisely, they are supported on sets "without
analytic structure". The result is mostly interesting when the potential has
regularity close to , because laminarity is expected to hold in that case.
We actually construct examples which are for all .Comment: Minor modifications. Final version, to appear in GAF
Effects of Climate Change on Phenology of Blackbirds and Orioles (Icterids) in Eastern South Dakota
Birds are among the first responders to climate change, often having clearly observable phenological responses to less perceptible levels of climate shift. Declines in populations of a number of bird species have been witnessed both in the United States and abroad, with up to a 48% decline in grassland birds of the Central U.S. Understanding changes in bird abundance and distribution is essential because birds supply a wide variety of critical ecosystem services, including pollination and pest control. While the effects of climate change on many bird species’ phenology have been studied intensely, research on the family Icteridae is limited. This study was conducted using spring bird presence and absence data and weather data from Oak Lake Field Station from 1995 to 2012. Linear regression analysis was applied against warmth sum days for the 30 days prior to each spring bird survey. Our analysis demonstrated significant increases in accumulated warmth sum days between 1999 and 2012 (P = 0.01). Icterid species richness also increased with increasing warmth sum days during the month leading up to surveys (P = 0.02). Trends in both habitat (open woodland, marsh, and grassland) and feeding guild (insectivores and omnivores) species richness were also observed with increasing warmth sum days. These findings suggest a shift towards earlier spring arrival of members of the family Icteridae in eastern South Dakota
Nowhere minimal CR submanifolds and Levi-flat hypersurfaces
A local uniqueness property of holomorphic functions on real-analytic nowhere
minimal CR submanifolds of higher codimension is investigated. A sufficient
condition called almost minimality is given and studied. A weaker necessary
condition, being contained a possibly singular real-analytic Levi-flat
hypersurface is studied and characterized. This question is completely resolved
for algebraic submanifolds of codimension 2 and a sufficient condition for
noncontainment is given for non algebraic submanifolds. As a consequence, an
example of a submanifold of codimension 2, not biholomorphically equivalent to
an algebraic one, is given. We also investigate the structure of singularities
of Levi-flat hypersurfaces.Comment: 21 pages; conjecture 2.8 was removed in proof; to appear in J. Geom.
Ana
On-Shell Recursion Relations for Generic Theories
We show that on-shell recursion relations hold for tree amplitudes in generic
two derivative theories of multiple particle species and diverse spins. For
example, in a gauge theory coupled to scalars and fermions, any amplitude with
at least one gluon obeys a recursion relation. In (super)gravity coupled to
scalars and fermions, the same holds for any amplitude with at least one
graviton. This result pertains to a broad class of theories, including QCD, N=4
SYM, and N=8 supergravity.Comment: 19 pages, 3 figure
Detection of chromosomal inversions using non-repetitive nucleic acid probes
A method for the identification of chromosomal inversions is described. Single-stranded sister chromatids are generated, for example by CO-FISH. A plurality of non-repetitive, labeled probes of relatively small size are hybridized to portions of only one of a pair of single-stranded sister chromatids. If no inversion exists, all of the probes will hybridize to a first chromatid. If an inversion has occurred, these marker probes will be detected on the sister chromatid at the same location as the inversion on the first chromatid
EBV Latent Membrane Protein 1 Activates Akt, NFκB, and Stat3 in B Cell Lymphomas
Latent membrane protein 1 (LMP1) is the major oncoprotein of Epstein-Barr virus (EBV). In transgenic mice, LMP1 promotes increased lymphoma development by 12 mo of age. This study reveals that lymphoma develops in B-1a lymphocytes, a population that is associated with transformation in older mice. The lymphoma cells have deregulated cell cycle markers, and inhibitors of Akt, NFκB, and Stat3 block the enhanced viability of LMP1 transgenic lymphocytes and lymphoma cells in vitro. Lymphoma cells are independent of IL4/Stat6 signaling for survival and proliferation, but have constitutively activated Stat3 signaling. These same targets are also deregulated in wild-type B-1a lymphomas that arise spontaneously through age predisposition. These results suggest that Akt, NFκB, and Stat3 pathways may serve as effective targets in the treatment of EBV-associated B cell lymphomas
Detection of Chromosomal Inversions Using Non-Repetitive Nucleic Acid Probes
A method and a kit for the identification of chromosomal inversions are described. Single-stranded sister chromatids are generated, for example by CO-FISH. A plurality of non-repetitive, labeled probes of relatively small size are hybridized to portions of only one of a pair of single-stranded sister chromatids. If no inversion exists, all of the probes will hybridize to a first chromatid. If an inversion has occurred, these marker probes will be detected on the sister chromatid at the same location as the inversion on the first chromatid
Note on New KLT relations
In this short note, we present two results about KLT relations discussed in
recent several papers. Our first result is the re-derivation of Mason-Skinner
MHV amplitude by applying the S_{n-3} permutation symmetric KLT relations
directly to MHV amplitude. Our second result is the equivalence proof of the
newly discovered S_{n-2} permutation symmetric KLT relations and the well-known
S_{n-3} permutation symmetric KLT relations. Although both formulas have been
shown to be correct by BCFW recursion relations, our result is the first direct
check using the regularized definition of the new formula.Comment: 15 Pages; v2: minor correction
Resonances of the cusp family
We study a family of chaotic maps with limit cases the tent map and the cusp
map (the cusp family). We discuss the spectral properties of the corresponding
Frobenius--Perron operator in different function spaces including spaces of
analytic functions. A numerical study of the eigenvalues and eigenfunctions is
performed.Comment: 14 pages, 3 figures. Submitted to J.Phys.
Note on Bonus Relations for N=8 Supergravity Tree Amplitudes
We study the application of non-trivial relations between gravity tree
amplitudes, the bonus relations, to all tree-level amplitudes in N=8
supergravity. We show that the relations can be used to simplify explicit
formulae of supergravity tree amplitudes, by reducing the known form as a sum
of (n-2)! permutations obtained by solving on-shell recursion relations, to a
new form as a (n-3)!-permutation sum. We demonstrate the simplification by
explicit calculations of the next-to-maximally helicity violating (NMHV) and
next-to-next-to-maximally helicity violating (N^2MHV) amplitudes, and provide a
general pattern of bonus coefficients for all tree-level amplitudes.Comment: 21 pages, 9 figures; v2, minor changes, references adde
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