45 research outputs found
Soliton Turbulence in Shallow Water Ocean Surface Waves
We analyze shallow water wind waves in Currituck Sound, North Carolina and
experimentally confirm, for the first time, the presence of
in ocean waves. Soliton turbulence is an exotic form of nonlinear
wave motion where low frequency energy may also be viewed as a
, described theoretically by the soliton limit of the
Korteweg-deVries (KdV) equation, a
: Hence the phrase "soliton turbulence" is synonymous with "integrable
soliton turbulence." For periodic/quasiperiodic boundary conditions the
of KdV are exactly solvable by
(FGT), the basis of our data analysis. We find that large amplitude measured
wave trains near the energetic peak of a storm have low frequency power spectra
that behave as . We use the linear Fourier transform to
estimate this power law from the power spectrum and to filter
from the data. We apply FGT to determine the
and find that the low frequency region
is . The solitons have , a
, which supports our interpretation
of the data as soliton turbulence. From the
we are able to demonstrate that the solitons are
and .Comment: 4 pages, 7 figure
Asymmetric leaves1 mediates leaf patterning and stem cell function in Arabidopsis
Meristem function in plants requires both the maintenance of
stem cells and the specification of founder cells from which lateral
organs arise. Lateral organs are patterned along proximodistal,
dorsoventral and mediolateral axes (1,2). Here we show that the
Arabidopsis mutant asymmetric leaves1 (as1) disrupts this process.
AS1 encodes a myb domain protein, closely related to
PHANTASTICA in Antirrhinum and ROUGH SHEATH2 in
maize, both of which negatively regulate knotted-class homeobox
genes. AS1 negatively regulates the homeobox genes KNAT1 and
KNAT2 and is, in turn, negatively regulated by the meristematic
homeobox gene SHOOT MERISTEMLESS. This genetic pathway
defines a mechanism for differentiating between stem cells and
organ founder cells within the shoot apical meristem and demonstrates
that genes expressed in organ primordia interact with
meristematic genes to regulate shoot morphogenesi
A Strawberry KNOX Gene Regulates Leaf, Flower and Meristem Architecture
The KNOTTED-LIKE HOMEODOMAIN (KNOX) genes play a central role in maintenance of the shoot apical meristem. They also contribute to the morphology of simple and compound leaves. In this report we characterize the FaKNOX1 gene from strawberry (Fragaria spp.) and demonstrate its function in trasgenic plants. The FaKNOX1 cDNA was isolated from a cultivated strawberry (F.×ananassa) flower EST library. The sequence is most similar to Class I KNOX genes, and was mapped to linkage group VI of the diploid strawberry genome. Unlike most KNOX genes studied, steady-state transcript levels were highest in flowers and fruits. Transcripts were also detected in emerging leaf primordia and the apical dome. Transgenic strawberry plants suppressing or overexpressing FaKNOX1 exhibited conspicuous changes in plant form. The FaKNOX1 RNAi plants presented a dwarfed phenotype with deeply serrated leaflets and exaggerated petiolules. They also exhibited a high level of cellular disorganization of the shoot apical meristem and leaves. Overexpression of FaKNOX1 caused dwarfed stature with wrinkled leaves. These gain- and loss-of-function assays in strawberry functionally demonstrate the contributions of a KNOX domain protein in a rosaceous species
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The human body at cellular resolution: the NIH Human Biomolecular Atlas Program
Abstract: Transformative technologies are enabling the construction of three-dimensional maps of tissues with unprecedented spatial and molecular resolution. Over the next seven years, the NIH Common Fund Human Biomolecular Atlas Program (HuBMAP) intends to develop a widely accessible framework for comprehensively mapping the human body at single-cell resolution by supporting technology development, data acquisition, and detailed spatial mapping. HuBMAP will integrate its efforts with other funding agencies, programs, consortia, and the biomedical research community at large towards the shared vision of a comprehensive, accessible three-dimensional molecular and cellular atlas of the human body, in health and under various disease conditions
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure