2,023 research outputs found
Urea and Fermentrol® additives for forage sorghum silage
Adding urea to forage sorghum greatly increased the ensiling temperature, produced a more rapid and extensive fermentation, and resulted in more shrink loss in the silo. Fermentrol®, an enzyme-inoculant additive, had very little affect on the silage temperature or chemical composition, but it did reduce the shrink loss. Calves red urea-treated silage had the poorest performance. Control and Fermentrol® silages each produced about 90 lb of calf gain per ton of crop ensiled, however urea silage produced only 60 lb. All three silages had short bunk lives throughout the trial
Genome-wide analysis points to roles for extracellular matrix remodeling, the visual cycle, and neuronal development in myopia
Myopia, or nearsightedness, is the most common eye disorder, resulting
primarily from excess elongation of the eye. The etiology of myopia, although
known to be complex, is poorly understood. Here we report the largest ever
genome-wide association study (43,360 participants) on myopia in Europeans. We
performed a survival analysis on age of myopia onset and identified 19
significant associations (p < 5e-8), two of which are replications of earlier
associations with refractive error. These 19 associations in total explain 2.7%
of the variance in myopia age of onset, and point towards a number of different
mechanisms behind the development of myopia. One association is in the gene
PRSS56, which has previously been linked to abnormally small eyes; one is in a
gene that forms part of the extracellular matrix (LAMA2); two are in or near
genes involved in the regeneration of 11-cis-retinal (RGR and RDH5); two are
near genes known to be involved in the growth and guidance of retinal ganglion
cells (ZIC2, SFRP1); and five are in or near genes involved in neuronal
signaling or development. These novel findings point towards multiple genetic
factors involved in the development of myopia and suggest that complex
interactions between extracellular matrix remodeling, neuronal development, and
visual signals from the retina may underlie the development of myopia in
humans
High moisture corn ensiled with urea
High moisture corn harvested at 18 and 26% moisture, rolled, treated with 0, .75, 1.5, or 2.25% urea (DM basis), and ensiled was evaluated for fermentation rate, chemical composition, and aerobic stability. Adding urea to 26% moisture corn increased the rate and extent of fermentation as measured by lactic, acetic, and total acid concentrations. Only a very limited fermentation occurred in the 18% moisture corn. No statistically significant differences were noted in DM loss or aerobic stability among the eight corn treatments
Efficient Replication of Over 180 Genetic Associations with Self-Reported Medical Data
While the cost and speed of generating genomic data have come down dramatically in recent years, the slow pace of collecting medical data for large cohorts continues to hamper genetic research. Here we evaluate a novel online framework for amassing large amounts of medical information in a recontactable cohort by assessing our ability to replicate genetic associations using these data. Using web-based questionnaires, we gathered self-reported data on 50 medical phenotypes from a generally unselected cohort of over 20,000 genotyped individuals. Of a list of genetic associations curated by NHGRI, we successfully replicated about 75% of the associations that we expected to (based on the number of cases in our cohort and reported odds ratios, and excluding a set of associations with contradictory published evidence). Altogether we replicated over 180 previously reported associations, including many for type 2 diabetes, prostate cancer, cholesterol levels, and multiple sclerosis. We found significant variation across categories of conditions in the percentage of expected associations that we were able to replicate, which may reflect systematic inflation of the effects in some initial reports, or differences across diseases in the likelihood of misdiagnosis or misreport. We also demonstrated that we could improve replication success by taking advantage of our recontactable cohort, offering more in-depth questions to refine self-reported diagnoses. Our data suggests that online collection of self-reported data in a recontactable cohort may be a viable method for both broad and deep phenotyping in large populations
Reconsidering the quantization of electrodynamics with boundary conditions and some measurable consequences
We show that the commonly known conductor boundary conditions
can be realized in two ways which we call 'thick' and 'thin'
conductor. The 'thick' conductor is the commonly known approach and includes a
Neumann condition on the normal component of the electric field
whereas for a 'thin' conductor remains without boundary condition.
Both types describe different physics already on the classical level where a
'thin' conductor allows for an interaction between the normal components of
currents on both sides. On quantum level different forces between a conductor
and a single electron or a neutral atom result. For instance, the
Casimir-Polder force for a 'thin' conductor is by about 13% smaller than for a
'thick' one.Comment: 22 pages, basic statement weakened, conclusions changed, misprints
correcte
Observation of modified radiative properties of cold atoms in vacuum near a dielectric surface
We have observed a distance-dependent absorption linewidth of cold Rb
atoms close to a dielectric-vacuum interface. This is the first observation of
modified radiative properties in vacuum near a dielectric surface. A cloud of
cold atoms was created using a magneto-optical trap (MOT) and optical molasses
cooling. Evanescent waves (EW) were used to observe the behavior of the atoms
near the surface. We observed an increase of the absorption linewidth with up
to 25% with respect to the free-space value. Approximately half the broadening
can be explained by cavity-quantum electrodynamics (CQED) as an increase of the
natural linewidth and inhomogeneous broadening. The remainder we attribute to
local Stark shifts near the surface. By varying the characteristic EW length we
have observed a distance dependence characteristic for CQED.Comment: 6 pages, 6 figures, some minor revision
Resonance phenomena in ultracold dipole-dipole scattering
Elastic scattering resonances occurring in ultracold collisions of either
bosonic or fermionic polar molecules are investigated. The Born-Oppenheimer
adiabatic representation of the two-bodydynamics provides both a qualitative
classification scheme and a quantitative WKB quantization condition that
predicts several sequences of resonant states. It is found that the
near-threshold energy dependence of ultracold collision cross sections varies
significantly with the particle exchange symmetry, with bosonic systems showing
much smoother energy variations than their fermionic counterparts. Resonant
variations of the angular distributions in ultracold collisions are also
described.Comment: 19 pages, 6 figures, revtex4, submitted to J. Phys.
Optics with an Atom Laser Beam
We report on the atom optical manipulation of an atom laser beam. Reflection,
focusing and its storage in a resonator are demonstrated. Precise and versatile
mechanical control over an atom laser beam propagating in an inhomogeneous
magnetic field is achieved by optically inducing spin-flips between atomic
ground states with different magnetic moment. The magnetic force acting on the
atoms can thereby be effectively switched on and off. The surface of the atom
optical element is determined by the resonance condition for the spin-flip in
the inhomogeneous magnetic field. A mirror reflectivity of more than 98% is
measured
An Efficient Data Structure for Dynamic Two-Dimensional Reconfiguration
In the presence of dynamic insertions and deletions into a partially
reconfigurable FPGA, fragmentation is unavoidable. This poses the challenge of
developing efficient approaches to dynamic defragmentation and reallocation.
One key aspect is to develop efficient algorithms and data structures that
exploit the two-dimensional geometry of a chip, instead of just one. We propose
a new method for this task, based on the fractal structure of a quadtree, which
allows dynamic segmentation of the chip area, along with dynamically adjusting
the necessary communication infrastructure. We describe a number of algorithmic
aspects, and present different solutions. We also provide a number of basic
simulations that indicate that the theoretical worst-case bound may be
pessimistic.Comment: 11 pages, 12 figures; full version of extended abstract that appeared
in ARCS 201
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