bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interrelationships between amino acid and glucose metabolism in

lambs of different dietary history supplemented with rumen escape

protein
Authors: ODDY V. H. , EDWARDS S. R. , WARREN H. M. , SPECK P. A. , NICHOLLS P. J. , NEUTZE S. A. 
Published: July 2002

Changes in amino acid and glucose metabolism in response to

increments of rumen escape protein (REP) were studied in groups of

lambs of three differing dietary histories and consequent weights,

but similar ages. Crossbred wether lambs (Merino × (Border

Leicester × Merino)) were fed to obtain three distinct growth

patterns. The LW group (n = 15) were offered a low quality

roughage diet throughout the experiment. The MW group (n = 19)

were offered a high quality mixed diet followed by the same low

quality diet as LW lambs. The HW group (n = 8) were offered a

high quality mixed diet throughout. All diets were offered once daily

ad libitum. The LW, MW and HW groups had liveweights of 18,

32 and 41 kg respectively at the commencement of supplementation, and

were 33±0·1 weeks of age. REP supplements

(formaldehyde-treated casein) were offered at 0, 20, 40, 60 or 80

g/day to MW and LW lambs and at 0 or 40 g/day to HW

lambs.REP increased basal digestible organic matter intake (DOMI),

liveweight gain (LWG) and urinary N excretion and tended to increase

N balance in LW and MW lambs. DOMI, N intake, N balance and LWG were

all higher (P < 0·05) in HW compared to MW and LW lambs.

REP tended (P < 0·10) to increase LWG in each dietary

history group.Blood glucose concentration was higher (P < 0·01) in HW

than in other lambs but was not significantly altered by REP

supplementation. Irreversible loss of glucose was greater (P <

0·01) in HW lambs and increased (P < 0·001) with REP

for LW and MW lambs. REP increased (P < 0·05) phenylalanine

(Phe) concentration in blood, Phe flux and oxidation and whole body

rates of protein synthesis and degradation. HW lambs had higher (P

< 0·05) values for all these parameters than did MW and LW

lambs.REP increased (P < 0·05) plasma concentrations of

insulin-like growth factor-1, and plasma insulin increased (P <

0·05) in MW but not in LW or HW lambs. REP had no effect on

plasma growth hormone (GH) concentration. Plasma concentration of

insulin was higher (P < 0·05) in HW than in MW or LW lambs,

while GH was not significantly affected by dietary history.The results show that supplementation of ruminant diets with REP

increases the rate of flux and oxidation of amino acids, and the rate

of glucose utilization. Amino acid supply appears to influence

glucose utilization more through oxidation rate than supply, and this

relationship is affected by previous dietary history (weight for age)

and energy availability, either from the diet or from body

stores.
Intake and digestibility of diets derived from stovers
and straws compared with lucerne hay and sweet
potato haulm
Authors: WILMAN D. , WEN LIAN , QIN HONGWEI , JI YILUN 
Published: July 2002

In order to learn more about the feeding value of stovers and straws,
seven diets were compared in
one experiment and nine in another. The diets in the first experiment were:
the upper and lower parts
of lucerne (Medicago sativa) hay, the leaves, upper stem and lower
stem of maize (Zea mays) stover
and the leaves and stem of sorghum (Sorghum vulgare) stover. The
diets in the second experiment
were: the upper and lower parts of lucerne hay, the leaves, stem and whole
stover of millet (Setaria
italica), the straw and chaff of wheat (Triticum aestivum),
rice (Oryza sativa) straw and sweet potato
(Ipomoea batatas) haulm. The diets were fed to sheep to record
rate of intake, voluntary intake and
in vivo digestibility. The diets were analysed for cell wall (as
neutral detergent fibre), crude protein and
lignin. Organic matter degradation and cell wall degradation were recorded
in nylon bags in the
rumen of cattle.The highest rates of intake (6·8–9·6 g dry matter/min)
and voluntary intake (75–103 g dry
matter/kg W0·75/day) were with sweet potato haulm
and the upper, leafy part of lucerne hay. The
voluntary intake of millet leaves, wheat chaff and the lower, stemmy part
of lucerne hay was
moderately high (46–70 g dry matter/kg W0·75/day).
Voluntary intake of leaves was higher than that
of stems in the case of millet, sorghum and to a lesser extent maize. The
lowest rates of intake were
with millet stem, sorghum stem and rice straw (1·8–2·4
g dry matter/min). In vivo digestibility of
organic matter was highest (59–67%) for the upper part of lucerne
hay, sweet potato haulm, the lower
part of maize stem and millet leaves. The leaves of maize were less digestible
than the stem, while the
reverse was the case with millet. Cell wall content was particularly high
(74–78% of dry matter) in
millet stem, wheat straw and chaff, rice straw and sorghum stem. Lignin
content was low (3·6–4·2%
of dry matter) in millet leaves, maize leaves and the upper part of maize
stem. Organic matter
degradation after 24 h incubation in the rumen was highest (80%) in sweet
potato haulm and lowest
(39–44%) in millet stem, wheat straw and chaff and rice straw. Cell
wall degradation after 96 h in the
rumen was highest (76–81%) with the leaves of maize, sorghum and
millet and lowest (40–59%) with
lucerne hay, millet stem and stover, wheat straw and chaff and rice straw.
Weeds and yields of spring cereals as influenced by
stubble-cultivation and reduced doses of
herbicides in five long-term trials
Authors: BOSTRÖM U. , HANSSON M. , FOGELFORS H. 
Published: July 2002

The influence of herbicides at reduced rates and repeated stubble-cultivation on weeds and crop yields
was estimated in five field trials with spring-sown cereals situated in the south of Sweden during the
autumn of 1989 until the spring of 1997. Stubble-cultivation was accomplished during 1989–1996,
while herbicides were applied at 0, 1/8, 1/4 or 1/2 of full dose during 1990–1996.In the spring of 1997, i.e. after 7 years without herbicide application, seedling densities 3 weeks after
weed emergence were 68–340/m2 at three sites and 535–610/m2 at two sites when averaged over tillage treatments.Averaged over herbicide doses, stubble-cultivation reduced the plant density of annual broad-
leaved weeds by 6–32% at three sites and increased the density by 25% at one site. At the remaining
site, the density was not significantly influenced. Stubble-cultivation reduced the populations of two
perennial and seven annual weed species, while one species was stimulated and nine species showed
null, or inconsistent, responses. In the spring of 1997, i.e. one year after the last herbicide application,
the densities of weed seedlings in 1/8, 1/4 and 1/2-doses were 34, 46 and 56% lower, respectively,
than in the untreated controls.Stubble-cultivation increased crop yields at four sites by 200 kg/ha as a mean over herbicide doses.
At these four sites, averaged over 1993–1995, herbicides increased yields in plots that were not
stubble-cultivated by 7, 8 and 10% in the 1/8, 1/4 and 1/2 of a full dose, respectively, relative to the
untreated control. In 1996, herbicides increased yields at only two sites.It is concluded that a fruitful way for weed management with a low input of agrochemicals is to
combine the use of herbicides at reduced rates with repeated stubble-cultivation.
α1c- and β2-adrenergic receptor mRNA distribution in the bovine mammary gland detected by competitive RT-PCR
Authors: WELLNITZ OLGA , ZURBRIGGEN ANDREAS , FRIIS ROBERT R. , BLUM JÜRG W. , BRUCKMAIER RUPERT M. 
Published: July 2002

Milk ejection and milk removal is considerably influenced by the sympathetic
nervous system. Stimulation of α-adrenergic receptors by administration of α-adrenergic
agonists inhibits alveolar milk ejection and milk removal in dairy cows
due to smooth muscle contraction (Blum et al. 1989; Bruckmaier et al. 1991).
However, contraction of the teat in response to α-adrenergic receptor stimulation has
no influence on milk flow as long as milk is available in the cistern (Bruckmaier et al.
1997). Therefore, α-adrenergic stimulation causes inhibition of transport of alveolar
milk into the cistern. On the contrary, the stimulation of β-adrenergic receptors
facilitates milk ejection and milk removal in dairy cows (Bernabé & Peeters, 1980;
Bruckmaier et al. 1991) because of muscle relaxation. Therefore, the distribution of
α- and β-adrenergic receptors plays an important role in the milkability of dairy
cows. However, from these in vivo studies it is not possible to distinguish between the
different α1- and α2- and β2-receptor subtypes owing to
the non-specific nature of the pharmacological agents used.To date, the precise tissue distribution of these different subtypes, in bovine
mammary tissue, is unknown. Using molecular techniques, we were interested in the
expression of genes that encode α1c and β2 as a preliminary study towards the
understanding of noradrenergic receptor-gene expression and regulation in this
important system.In addition, α1c- and β2-adrenergic receptors were determined in front and rear
quarters of the mammary gland to investigate differences in receptor distribution
within the udder and possible relations between adrenergic receptor distribution and
the higher milk flow rates in rear than in front quarters (Rothenanger et al. 1995).
Kicked Burgers turbulence
Authors: BEC J. , FRISCH U. , KHANIN K. 
Published: July 2002

Burgers turbulence subject to a force f(x, t) =
[sum ]jfj(x)δ(t − tj), where tj are 'kicking times' and the 'impulses' fj(x) have arbitrary space dependence, combines
features of the purely decaying and the continuously forced cases. With large-scale
forcing this ‘kicked’ Burgers turbulence presents many of the regimes proposed by E
et al. (1997) for the case of random white-noise-in-time forcing. It is also amenable to
efficient numerical simulations in the inviscid limit, using a modification of the fast
Legendre transform method developed for decaying Burgers turbulence by Noullez
& Vergassola (1994). For the kicked case, concepts such as ‘minimizers’ and ‘main
shock’, which play crucial roles in recent developments for forced Burgers turbulence,
become elementary since everything can be constructed from simple two-dimensional
area-preserving Euler–Lagrange maps.The main results are for the case of identical deterministic kicks which are periodic
and analytic in space and are applied periodically in time. When the space integrals of
the initial velocity and of the impulses vanish, it is proved and illustrated numerically
that a space- and time-periodic solution is achieved exponentially fast. In this regime,
probabilities can be defined by averaging over space and time periods. The probability
densities of large negative velocity gradients and of (not-too-large) negative velocity
increments follow the power law with −7/2 exponent proposed by E et al. (1997) in
the inviscid limit, whose existence is still controversial in the case of white-in-time
forcing. This power law, which is seen very clearly in the numerical simulations, is the
signature of nascent shocks (preshocks) and holds only when at least one new shock
is born between successive kicks.It is shown that the third-order structure function over a spatial separation Δx
is analytic in Δx although the velocity field is generally only piecewise analytic (i.e.
between shocks). Structure functions of order p ≠ 3 are non-analytic at Δx = 0.
For even p there is a leading-order term proportional to [mid ]Δx[mid ] and for odd
p > 3 the leading-order term ∝Δx has a non-analytic correction
∝Δx[mid ]Δx[mid ] stemming from shock mergers.
Non-axisymmetric rotating-disk flows: nonlinear travelling-wave states
Authors: HEWITT R. E. , DUCK P. W. 
Published: July 2002

We consider the classical problem of the laminar flow of an incompressible rotating
fluid above a rotating, impermeable, infinite disk. There is a well-known class of
solutions to this configuration in the form of an exact axisymmetric solution to the
Navier–Stokes equations. However, the radial self-similarity that leads to the ‘rotating-
disk equations’ can also be used to obtain solutions that are non-axisymmetric
in nature, although (in general) this requires a boundary-layer approximation. In
this manner, we locate several new solution branches, which are non-axisymmetric
travelling-wave states that satisfy axisymmetric boundary conditions at infinity and at
the disk. These states are shown to appear as symmetry-breaking bifurcations of the
well-known axisymmetric solution branches of the rotating-disk equations. Numerical
results are presented, which suggest that an infinity of such travelling states exist in
some parameter regimes. The numerical results are also presented in a manner that
allows their application to the analogous flow in a conical geometry.Two of the many states described are of particular interest. The first is an exact,
nonlinear, non-axisymmetric, stationary state for a rotating disk in a counter-rotating
fluid; this solution was first presented by Hewitt, Duck & Foster (1999) and here we
provide further details. The second state corresponds to a new boundary-layer-type
approximation to the Navier–Stokes equations in the form of azimuthally propagating
waves in a rotating fluid above a stationary disk. This second state is a new non-axisymmetric alternative to the classical axisymmetric Bödewadt solution.
The response of a mixing layer formed between parallel streams to a concomitant excitation at two frequencies
Authors: DE ZHOU MING , WYGNANSKI I. 
Published: July 2002

Simultaneous excitation of a turbulent mixing layer by two frequencies, a fundamental
and a subharmonic, was investigated experimentally. Plane perturbations were
introduced to the flow at its origin by a small oscillating flap. The results describe
two experiments that differ mainly in the amplitudes of the imposed perturbations
and both are compared to the data acquired while the mixing layer was forced at a
single frequency.Conventional statistical quantities such as: mean velocity profiles, widths of the
flow, turbulent intensities, spectra, phase-locked velocity and vorticity fields, as well
as streaklines were computed. The rate of spread of the flow under concomitant
excitation at the two frequencies was much greater than under a single frequency,
although it remained dominated by two-dimensional eddies. The Reynolds stresses
and turbulence production are associated with the deformation and orientation of the
large coherent vortices. When the major axis of the coherent vortices starts leaning
forward on the high-speed side of the flow, the production of turbulent energy changes
sign (i.e. becomes negative) and this results in the flow thinning in the direction of
streaming. It also indicates that energy is extracted from the turbulence to the mean
motion. Resonance phenomena play an important role in the evolution of the flow. A
vorticity budget showed that the change in mean vorticity was mainly caused by the
nonlinear interaction between coherent vorticities. Nevertheless, the locally dominant
frequency scales the mean growth rate, the inclination and distortion of the mean
velocity profiles as well as the phase-locked vorticity contours.
Lateral boundary contributions to wave-activity

invariants and nonlinear stability theorems for balanced dynamics
Authors: REN SHUZHAN , SHEPHERD THEODORE G. 
Published: July 2002

The slow advective-timescale dynamics of the atmosphere and

oceans is referred

to as balanced dynamics. An extensive body of theory for disturbances to
basic

flows exists for the quasi-geostrophic (QG) model of balanced dynamics,
based

on wave-activity invariants and nonlinear stability theorems associated
with exact

symmetry-based conservation laws. In attempting to extend this theory to
the

semi-geostrophic (SG) model of balanced dynamics, Kushner &

Shepherd discovered lateral

boundary contributions to the SG wave-activity invariants which are not
present in

the QG theory, and which affect the stability theorems. However, because
of technical

difficulties associated with the SG model, the analysis of Kushner &
Shepherd was

not fully nonlinear.This paper examines the issue of lateral boundary contributions to wave-activity

invariants for balanced dynamics in the context of Salmon's

nearly geostrophic model

of rotating shallow-water flow. Salmon's model has

certain similarities with the SG

model, but also has important differences that allow

the present analysis to be carried

to finite amplitude. In the process, the way in which constraints produce
boundary

contributions to wave-activity invariants, and additional

conditions in the associated

stability theorems, is clarified. It is shown that Salmon's

model possesses two kinds

of stability theorems: an analogue of Ripa's small-amplitude

stability theorem for shallow-water flow, and a finite-amplitude analogue
of Kushner

& Shepherd's SG

stability theorem in which the ‘subsonic’ condition of

Ripa's theorem is replaced by a

condition that the flow be cyclonic along lateral boundaries.

As with the SG theorem,

this last condition has a simple physical interpretation involving the
coastal Kelvin

waves that exist in both models.Salmon's model has recently emerged as an important prototype for
constrained

Hamiltonian balanced models. The extent to which the present analysis applies
to

this general class of models is discussed.
A viscoelastic model for turbulent flow over
undulating topography
Authors: ZOU QINGPING 
Published: July 2002

Aviscoelastic model (a mixing-length model with
relaxation) is developed to investigate
the effect of turbulent advection on the mean flow
perturbation and the drag force
induced by turbulent shear flow over an undulating surface.
The relaxation term is
proportional to the ratio of eddy turnover time to travelling
time; accordingly, near the
surface, the relaxation model reduces to an eddy-viscosity or
mixing-length model,
while far from the surface it reduces to a rapid-distortion model.The linear governing equations are transformed into
streamline coordinates and
solved through matched asymptotic expansions. According to
order-of-magnitude
estimates in Belcher, Newley & Hunt (1993), the drag
force contributed by nonlinear
shear stress is of the same order as that contributed by
asymmetric pressure arising
from the leeward thickening of the perturbed boundary
layer. The nonlinear analysis
in the present model confirms this estimate in most cases.
Our analytical results show
a dip in shear stress at the interface between the inner
and outer layers and provide
evidence that this dynamical feature is related to eddy
advection. Numerical calculation
using a shooting method gives results that compare well
with the analysis.
Stability of fluid flow in a flexible tube to non-axisymmetric disturbances
Authors: SHANKAR V. , KUMARAN V. 
Published: July 2002

The stability of fluid flow in a flexible tube to non-axisymmetric perturbations is
analysed in this paper. In the first part of the paper, the equivalents of classical
theorems of hydrodynamic stability are derived for inviscid flow in a flexible tube
subjected to arbitrary non-axisymmetric disturbances. Perturbations of the form
vi = v˜i exp
[ik(x − ct) + inθ] are imposed on a
steady axisymmetric mean flow U(r) in a flexible
tube, and the stability of mean flow velocity profiles and bounds for
the phase velocity of the unstable modes are determined for arbitrary values of
azimuthal wavenumber n. Here r, θ and x are
respectively the radial, azimuthal and axial coordinates, and
k and c are the axial wavenumber and phase velocity
of disturbances. The flexible wall is represented by a standard constitutive relation
which contains inertial, elastic and dissipative terms. The general results indicate
that the fluid flow in a flexible tube is stable in the inviscid limit if the quantity
Ud[Gscr ]/dr [ges ] 0, and could be unstable for
Ud[Gscr ]/dr < 0, where [Gscr ] ≡
rU′/(n2 + k2r2).
For the case of Hagen–Poiseuille flow, the general result implies that the flow is stable
to axisymmetric disturbances (n = 0), but could be unstable to non-axisymmetric
disturbances with any non-zero azimuthal wavenumber (n ≠ 0). This is in marked
contrast to plane parallel flows where two-dimensional disturbances are always more
unstable than three-dimensional ones (Squire theorem). Some new bounds are derived
which place restrictions on the real and imaginary parts of the phase velocity for
arbitrary non-axisymmetric disturbances.In the second part of this paper, the stability of the Hagen–Poiseuille flow in
a flexible tube to non-axisymmetric disturbances is analysed in the high Reynolds
number regime. An asymptotic analysis reveals that the Hagen–Poiseuille flow in a
flexible tube is unstable to non-axisymmetric disturbances even in the inviscid limit,
and this agrees with the general results derived in this paper. The asymptotic results
are extended numerically to the moderate Reynolds number regime. The numerical results reveal
that the critical Reynolds number obtained for inviscid instability to non-axisymmetric
disturbances is much lower than the critical Reynolds numbers obtained in the previous studies
for viscous instability to axisymmetric disturbances when the dimensionless parameter
Σ = ρGR2/η2 is large.
Here G is the shear modulus of the elastic medium,
ρ is the density of the fluid, R is the radius of the tube and
η is the viscosity of the fluid. The viscosity of the wall medium is found to have a
stabilizing effect on this instability.
Decision-making cognition in mania and depression
Authors: MURPHY F. C. , RUBINSZTEIN J. S. , MICHAEL A. , ROGERS R. D. , ROBBINS T. W. , PAYKEL E. S. , SAHAKIAN B. J. 
Published: July 2002

Background. Despite markedly different clinical presentations, few studies have reported differences in neuropsychological functioning between mania and depression. Recent work has suggested that differences may emerge on cognitive tasks requiring affective processing, such as decision-making. The present study sought to compare decision-making cognition in mania and depression in order to clarify the current profiles of impairment for these disorders and to contribute to our more general understanding of the relationship between mood and cognition.Methods. Medicated manic patients, depressed patients, and normal healthy controls completed a computerized decision-making task. All subjects were asked to win as many points as possible by choosing outcomes based on variably-weighted probabilities and by placing ‘bets’ on each decision.Results. Both patient groups were impaired on this task, as evidenced by slower deliberation times, a failure to accumulate as many points as controls and suboptimal betting strategies. Manic, but not depressed, patients made suboptimal decisions – an impairment that correlated with the severity of their illness.Conclusions. These findings are consistent with a growing consensus that manic and depressed patients are characterized by significant impairments in cognitive and particularly executive, functioning. Furthermore, the distinct patterns of observed impairment in manic and depressed patients suggests that the nature and extent of cognitive impairment differ between these two groups. Viewed in the context of other recent studies, these findings are consistent with a role for the ventromedial prefrontal cortex in mediating mood–cognition relationships.