917 research outputs found
Wheat middlings in high concentrate rations: digestibility and ruminal metabolism
Six medium-framed steers, fitted with
ruminal cannulae were used in a 6 × 6 Latin
square design and fed the following six high
concentrat e (90%) rations: control; 5, 10, or
15% pelleted wheat middlings (WM) replacing
the concentrate (dry rolled corn); and 5 or 10%
pelleted WM replacing the roughage (chopped
alfalfa hay). Dry matter (DM), organic matter
(OM), and starch digestibilities decreased
linearly when increasing levels of WM replaced
the concentrate , but replacing the roughage increased
DM and OM digestibilities linearly.
WM could replace only up to 5 % of the concentrate
without reducing nutrient digestibilities,
but complete (10% WM) replacement of the
roughage increased nutrient digestibilities
Losses from top spoilage in horizontal silos
The top 3 ft of silage from 127 horizontal
silos was sampled at three locations across the
width of the silo during a 4-year period (1990
through 1993). Ninety-six percent of the silages
were either corn or forage sorghum, and only 18
percent of the silos were sealed with
polyethylene sheeting . Losses of organic matter
(OM) from spoilage were estimated by using
ash content as an internal marker. Sealing silos
dramatically reduced the estimated spoilage
losses in the top 3 ft.
All silages had greater estimated spoilage
losses in the top 18 inches in 1991 and 1993
than 1990 and 1992. Sealing reduced spoilage
losses of OM in the to p 18 inches by 16, 37, 19,
and 36 percentage units in 1990 through 1993,
respectively , and in the second 18 inches by 4,
13, 3, and 7 percentage units.
Dry matter (DM) contents were lower for
forage sorghum silages in the top 18 inches than
for corn silages in the first 3 years, and i n all 4
years, DM contents for sealed silages were
lower than those for unsealed silages. Silage
had higher pH values in the top 1 8 inches than
in the second 18 inches
Improving silage quality
Results at Kansas State University from over 200 laboratory-scale trials and 28 farm-scale trials showed that bacterial inoculants consistently improved preservation efficiency and nutritive value of the ensiled material. In contrast, anhydrous ammonia or urea decreased dry matter recovery and production per ton of crop ensiled. Economic analysis also favored the use of bacterial inoculants over nonprotein nitrogen additives. Research conducted using corn, sorghum, and alfalfa silages showed that sealing the exposed surface dramatically reduced top spoilage losses in bunker, trench, or stack silos
From limit cycles to strange attractors
We define a quantitative notion of shear for limit cycles of flows. We prove
that strange attractors and SRB measures emerge when systems exhibiting limit
cycles with sufficient shear are subjected to periodic pulsatile drives. The
strange attractors possess a number of precisely-defined dynamical properties
that together imply chaos that is both sustained in time and physically
observable.Comment: 27 page
Agronomic and silage quality traits of forage sorghum cultivars in 1995
Agronomic and silage quality traits were
measure d for 37 forage sorghum cultivars and
three grain sorghum hybrids. The 1995 growing
season was characterized by above average
rainfall in the spring and early summer, and a
hard freeze on September 22. At the time of
the freeze, 20 cultivars had reached the early-milk
to early-dough stage, 12 were in the
bloom stage, and the remaining eight were still
in the early- to late-boot stage . The late planting
date and low plant populations resulted in
below-normal whole-plant D M and grain yields.
Plant height s for the grain sorghums were near
normal, but the forage sorghums were well
below expected plant heights. The preensiled,
whole-plan t DM contents of the 37 forage
sorghums ranged from 23.0 to 39.9%. As
expected , the silage nutritive value traits of CP,
NDF, and ADF were most favorable for the
three grain sorghum hybrids and least favorable
for the eight forage sorghum hybrids that were
still in the boot stage when the freeze occurred
Selectivity and functional diversity in arbuscular mycorrhizas of co-occurring fungi and plants from a temperate deciduous woodland
1 The arbuscular mycorrhizal (AM) fungi colonizing plants at a woodland site in North Yorkshire (UK) have been characterized from the roots of five plant species (Rubus fruticosus agg. L., Epilobium angustifolium L., Acer pseudoplatanus L., Ajuga reptans L. and Glechoma hederacea L.), and identified using small-subunit rRNA (SSUrRNA) gene amplification and sequencing. 2 Interactions between five plant species from the site and four co-occurring glomalean fungi were investigated in artificial one-to-one AM symbioses. Three of the fungi were isolated from the site; the fourth was a culture genetically similar to a taxon found at the site. Phosphorus uptake and growth responses were compared with non-mycorrhizal controls. 3 Individual fungi colonized each plant with different spatial distribution and intensity. Some did not colonize at all, indicating incompatibility under the conditions used in the experiments. 4 Glomus hoi consistently occupied a large proportion of root systems and outperformed the other fungi, improving P uptake and enhancing the growth of four out of the five plant species. Only G. hoi colonized and increased P uptake in Acer pseudoplatanus, the host plant with which it associates almost exclusively under field conditions. Colonization of all plant species by Scutellospora dipurpurescens was sparse, and beneficial to only one of the host plants (Teucrium scorodonia). Archaeospora trappei and Glomus sp. UY1225 had variable effects on the host plants, conferring a range of P uptake and growth benefits on Lysimachia nummularia and T. scorodonia, increasing P uptake whilst not affecting biomass in Ajuga reptans and Glechoma hederacea, and failing to form mycorrhizas with A. pseudoplatanus. 5 These experimental mycorrhizas show that root colonization, symbiont compatibility and plant performance vary with each fungus-plant combination, even when the plants and fungi naturally co-exist. 6 We provide evidence of physical and functional selectivity in AM. The small number of described AM fungal species (154) has been ascribed to their supposed lack of host specificity, but if the selectivity we have observed is the general rule, then we may predict that many more, probably hard-to-culture glomalean species await discovery, or that members of species as currently perceived may be physiologically or functionally distinct
On the spherical-axial transition in supernova remnants
A new law of motion for supernova remnant (SNR) which introduces the quantity
of swept matter in the thin layer approximation is introduced. This new law of
motion is tested on 10 years observations of SN1993J. The introduction of an
exponential gradient in the surrounding medium allows to model an aspherical
expansion. A weakly asymmetric SNR, SN1006, and a strongly asymmetric SNR,
SN1987a, are modeled. In the case of SN1987a the three observed rings are
simulated.Comment: 19 figures and 14 pages Accepted for publication in Astrophysics &
Space Science in the year 201
Water-like anomalies for core-softened models of fluids: One dimension
We use a one-dimensional (1d) core-softened potential to develop a physical
picture for some of the anomalies present in liquid water. The core-softened
potential mimics the effect of hydrogen bonding. The interest in the 1d system
stems from the facts that closed-form results are possible and that the
qualitative behavior in 1d is reproduced in the liquid phase for higher
dimensions. We discuss the relation between the shape of the potential and the
density anomaly, and we study the entropy anomaly resulting from the density
anomaly. We find that certain forms of the two-step square well potential lead
to the existence at T=0 of a low-density phase favored at low pressures and of
a high-density phase favored at high pressures, and to the appearance of a
point at a positive pressure, which is the analog of the T=0 ``critical
point'' in the Ising model. The existence of point leads to anomalous
behavior of the isothermal compressibility and the isobaric specific heat
.Comment: 22 pages, 7 figure
Adsorption of mono- and multivalent cat- and anions on DNA molecules
Adsorption of monovalent and multivalent cat- and anions on a deoxyribose
nucleic acid (DNA) molecule from a salt solution is investigated by computer
simulation. The ions are modelled as charged hard spheres, the DNA molecule as
a point charge pattern following the double-helical phosphate strands. The
geometrical shape of the DNA molecules is modelled on different levels ranging
from a simple cylindrical shape to structured models which include the major
and minor grooves between the phosphate strands. The densities of the ions
adsorbed on the phosphate strands, in the major and in the minor grooves are
calculated. First, we find that the adsorption pattern on the DNA surface
depends strongly on its geometrical shape: counterions adsorb preferentially
along the phosphate strands for a cylindrical model shape, but in the minor
groove for a geometrically structured model. Second, we find that an addition
of monovalent salt ions results in an increase of the charge density in the
minor groove while the total charge density of ions adsorbed in the major
groove stays unchanged. The adsorbed ion densities are highly structured along
the minor groove while they are almost smeared along the major groove.
Furthermore, for a fixed amount of added salt, the major groove cationic charge
is independent on the counterion valency. For increasing salt concentration the
major groove is neutralized while the total charge adsorbed in the minor groove
is constant. DNA overcharging is detected for multivalent salt. Simulations for
a larger ion radii, which mimic the effect of the ion hydration, indicate an
increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure
Calibration of Super-Kamiokande Using an Electron Linac
In order to calibrate the Super-Kamiokande experiment for solar neutrino
measurements, a linear accelerator (LINAC) for electrons was installed at the
detector. LINAC data were taken at various positions in the detector volume,
tracking the detector response in the variables relevant to solar neutrino
analysis. In particular, the absolute energy scale is now known with less than
1 percent uncertainty.Comment: 24 pages, 16 figures, Submitted to NIM
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