bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein supplementation of grass silages of differing digestibility for growing steers
Authors: SCOLLAN N. D. , SARGEANT A. , McALLAN A. B. , DHANOA M. S.
Published: July 2002

Previous studies have demonstrated that protein sources which are primarily degraded in the rumen
such as rapeseed meal or soyabean meal may be as effective as a less rumen degradable protein source
such as fishmeal in supporting higher levels of animal performance in young steers fed on grass silage.
However, the response to type of protein supplement is likely to be influenced by the composition of
the basal diet. This study has examined the effect of supplementing silages prepared from early (EH)
and late (LH) harvested grass with two protein sources of differing rumen degradability, rapeseed
meal (RSM) and fishmeal (FM) or a mixture of the two (M), thus creating eight experimental diets
of LH, LHRSM, LHFM, LHM, EH, EHRSM, EHFM and EHM. Silage was offered ad libitum and
supplements were included at 100 g fresh weight/kg silage DM intake. The RSM and M diets were
made isonitrogenous with FM diets by the addition of urea. Animals remained on diets for 18 weeks
and liveweights were monitored for a further 13 weeks while the animals were at pasture. Dry matter
(DM) intakes and liveweight gains were higher with EH than with LH silage (P < 0·001). Response
to type of protein supplement was dependent on silage quality. On LH silage, higher intakes were
noted on FM and M (82·4 and 82·8 g DM/unit metabolic liveweight/day, respectively) relative to
silage only (75·8 g DM/unit metabolic liveweight/day) and this contributed towards higher liveweight
gains (P < 0·01). Liveweight gains tended to be higher on LH silage supplemented with FM
compared to RSM (0·76 v. 0·67 kg/day, respectively, P = 0·08). In comparison, on EH silage, relative
to EH unsupplemented, the intake was highest on M (89·2 v. 96·6 g DM/unit metabolic
liveweight/day), but liveweight gains were not significantly different between supplements. On
turnout to pasture, those animals fed on silage alone exhibited compensatory growth (P < 0·025) with
the result that those fed on LH silage only grew faster and achieved the same liveweight after 13 weeks
at grass as those supplemented with RSM or M. There was a tendency for those fed on FM to
maintain an advantage in liveweight after the period at pasture. On EH silage, at the end of the
grazing period no significant differences in liveweight existed between the different supplements and
on average were 23 kg heavier than EH silage unsupplemented. In conclusion, silage type (stage of
harvest and quality) and protein supplementation influenced animal performance. On late harvest
and poorer digestibility silage, there was some indication that feeding fishmeal was better than
rapeseed but this was less evident on early harvest and higher digestibility silage. However,
considering the price differential between these two supplements and small difference in animal
performance it is concluded that rapeseed meal is as effective as fishmeal when used as a protein
supplement for growing cattle fed on grass silage.
Complementarity of bird-resistant and
non-bird-resistant varieties of sorghum stover with
cottonseed cake and noug (Guizotia abyssinica) cake
when fed to sheep
Authors: NSAHLAI I. V. , UMUNNA N. N. , OSUJI P. O.
Published: July 2002

A study was conducted to examine whether oilseed cakes
(cottonseed cake (CSC) or noug (Guizotia abyssinica)
cake (NSC)) are complementary to the bird-resistant
(BR) and non-bird-resistant (NBR)
varieties of sorghum stover and whether sheep select against
morphological fractions containing high
concentrations of tannins or proanthocyanidins (PA). Either
24 (growth study) or 16 (metabolism
study) Ethiopian Menz sheep were used in a randomized complete
block design to study the
interaction of variety of sorghum stover with type of oilseed
cake on feed selection, intake,
digestibility, microbial protein synthesis, nitrogen (N)
retention and growth. The degradability of the
feeds and refusals was also determined. The NBR variety was
more degradable than the BR variety
during the early hours of incubation. NSC degraded faster,
although to a lesser extent than CSC.
Stover variety had no effect on ruminal ammonia concentration
(RAC) while CSC induced a higher
RAC than NSC did. Sheep given the NBR variety had more dust,
less heads, less leaf, less sheath and
more stem in their ingesta than those fed on the BR variety.
It was seen that the sheep discriminated
against the stems, since the ratio of stem in ingesta to stem
on offer was <1. Since PA are more highly
concentrated in the sheath than in any of the other plant
fractions, it appears that the choice of the
morphological composition of the ingesta by sheep was not
determined by PA. Sheep selected a diet
which was 2–5% or 5–11% more degradable than the
offered or refused feeds, respectively. Relative
to NSC, CSC enhanced the intake of N, N bound to neutral
detergent fibre (NDF), digestibility and
N retention and tended to increase (P<0·06)
liveweight gain (LWG) and organic matter (OM) intake
but had no effect on microbial protein synthesis. Compared
with the NBR variety, the BR variety
depressed N digestibility and N retention, had no effect
on microbial protein synthesis and on LWG,
but depressed the efficiency of LWG by c. 30%. Sheep
given the BR+NSC diet had the lowest daily
gain but excreted copious amounts of urine, probably in an
attempt to eliminate toxic waste
substances. Since sorghum is a crop of the semi-arid regions,
it is quite likely that, although the bird
resistance trait increases crop yield, it has resulted in a
feed that is rather less suitable for livestock
in this production environment, where water shortages are
frequent. In-depth studies on the
consequences of water shortage on the utilization of
bird-resistant sorghum stover are required.
Crop management systems for rainfed and irrigated
sunflower (Helianthus annuus) in south-western France
Authors: DEBAEKE P. , CABELGUENNE M. , HILAIRE A. , RAFFAILLAC D.
Published: July 2002

In the context of EEC agricultural policy, the efficient production
of sunflower
(Helianthus annuus L.)
requires the development of a wider range of crop management schemes than
were used previously.
Five different management options were applied to sunflower over
a period of 10 years (1984–94) on
a deep silty clay soil at Auzeville, near Toulouse, south-western France,

combining different levels of
crop density, N fertilization and supplementary irrigation. The
effectiveness of these practices was
evaluated on the basis of grain yield, oil production, amount of
disease infection, N leaching, soil
water deficit and economic return, using both experimental values
and simulations with the epic-phase model.

Grain yield ranged from 1 t/ha (with severe disease incidence)
to 4 t/ha (no diseases, full
irrigation). There was no evidence of higher yield variability between

years for low-input cropping systems managed without irrigation.

In the deep soils of Auzeville, c.100 mm of irrigation,
split into two or three applications around
flowering, appeared to be a good strategy for maximizing irrigation
efficiency. Limiting leaf area
expansion under rainfed management, by reducing crop density and
N fertilization, limited stem
infection frequency by Phomopsis helianthi and delayed
soil water depletion, thus maximizing grain
yield. Oil concentration was generally higher under full irrigation,
but high values were also observed
under rainfed conditions provided that a suitable genotype was used. The
annual amount of N
leaching, simulated by epic-phase, ranged from 17 to
40 kg/ha depending on N amount and
irrigation volume. Under the current conditions of the Common
Agricultural Policy, low-input and
rainfed management appeared to be the most profitable strategy for
the deep soils of south-western France.
A comparative study on growth, body composition and
carcass tissue distribution in Omani sheep and goats
Authors: MAHGOUB O. , LODGE G. A.
Published: July 2002

Growth, body composition and distribution of carcass tissues were
compared in Omani sheep and
goats. Animals had ad libitum access to Rhodes-grass hay (8 %
CP) and a concentrate diet (16% CP)
from weaning until slaughter. The two species had similar birth weights
but sheep had higher
preweaning (181 g/day), postweaning (175 g/day) and overall (179
g/day) growth rates than goats
(120, 102 and 111 g/day, respectively) and thus they reached slaughter
weights earlier. Sheep had
higher slaughter weight (22·26 kg), empty body weight (20·39
kg), hot carcass weight (12·48 kg) and
dressing out percentage (55·94%) than goats (21·17, 18·82,
11·48 kg and 53·97%, respectively).
Sheep also had higher proportions of skin, liver and lungs and trachea
(P<0·01) than goats, which
had higher proportions of head, feet and gut contents. As proportions of
carcass weight, sheep had
higher fat (25·08%) but lower muscle content (57·24%) than
goats (15·72 and 65·88%, respectively).
There were no significant differences between the two species in proportion
of carcass bone (13·76 and
14·17%). These effects resulted in sheep having a lower muscle:
bone ratio (4·19 and 4·68) and higher
fat: muscle ratio (0·44 and 0·24). Sheep had higher proportions
of non-carcass, carcass and total body
fat in the empty body weight (EBW) than goats. However, sheep had less
non-carcass but more
carcass fat than goats when fats were expressed as proportions of total
body fat. Sheep had higher
proportions of muscles in the proximal hind limb, distal hind limb (P<0·01),
around the spinal
column, connecting forelimb to thorax and high-priced muscle group (P<0·05),
but lower
proportions of muscles in the abdominal wall, proximal forelimb (P<0·05),
distal forelimb
(P<0·01), connecting neck to forelimb, intrinsic muscles
of
neck and thorax (P<0·05) and total
forequarter muscles (P<0·01) than goats. As proportions
in carcass bone, sheep had higher axial
skeleton (P<0·05) but lower forelimb than goats. Among
species/sex/slaughter weight groups,
castrated male and female goats had the lowest growth rates. Castrates
and female sheep, particularly
at heavier liveweights, had higher carcass and non-carcass fat contents
than intact males and goats
of all sexes. Although Omani goats produced leaner carcasses and had higher
proportions of some
non-carcass offals than Omani sheep, they had slower growth rates and a
less attractive muscle
distribution. This may negatively affect their potential for large scale
meat production under Omani
conditions.
The Country in the City: Central Park in Jonas Mekas's

Walden and William Greaves's

Symbiopsychotaxiplasm: Take One
Authors: MACDONALD SCOTT
Published: July 2002

On a map or from the air, nothing defines New York City

more clearly than the rectilinearity of Central Park at the heart of the

curvilinear island

of Manhattan. And nothing encodes the paradox of the thinking that

created Frederick Law Olmsted's first great park

– and simultaneously

distinguishes it from many of the parks inspired by Central Park

– than the

virtually perfect geometry of its outline. The Park simultaneously

confirms the grid structure of the streets of Manhattan and dramatically

interrupts this structure: streets that run vertically uptown and downtown

or horizontally across town must, when they reach the horizontal and

vertical boundaries of the park, leave their verticality and horizontality

behind to traverse the Park before rejoining the grid of streets and

avenues at the far boundaries of the Park's expanse.

If the Cartesian clarity

of midtown Manhattan has come to represent the efficiency of American

capitalism that was making the United States a major industrial power

during the years when the Greensward Plan was designed and Central

Park constructed, the Park represented (and continues to represent) a

counter-sensibility: as Olmstead and Vaux predicted.
SPOUSES’ SOCIOECONOMIC CHARACTERISTICS AND FERTILITY DIFFERENCES IN SUB-SAHARAN AFRICA: DOES SPOUSE’S EDUCATION MATTER?
Authors: MASUDI UCHUDI JOSEPH
Published: July 2002

Although the general objective of this study is to examine the extent to which spouses’ socioeconomic characteristics determine whether modern contraception is used and whether family limitation (the demand for no more children) is desired, its central goal is to evaluate the degree to which the net effect of a woman’s education on those fertility decisions is altered once a control is made for the level of schooling of the husband. Individual characteristics of spouses included as controls in this analysis are on the one hand women’s attributes relating to employment, age, parity, ethnic identity, and urban residence and, on the other hand, the occupation of the husband. Data used in this research are provided by DHS surveys conducted in fourteen sub-Saharan countries: Mali, Burkina Faso, Niger, Nigeria, Cameroon, Benin, Senegal, Ghana, Central African Republic, Kenya, Zambia, Zimbabwe, Namibia and Rwanda. With two dichotomous outcome variables, logistic regression was used to estimate two nested models for each dependent variable and for each country covered by the study. DHS respondents used as units of analysis in this study are women who were married (any kind of union) and non-pregnant at the time when each national survey was conducted. The findings suggest that, while an educated wife needs the support of an educated husband to state a preference for family limitation in contemporary sub-Saharan Africa, controlling for husband’s education and other relevant covariates does little to undermine the evidence that woman’s advanced education and the adoption of modern family planning are positively related in the developing world.
LATERALIZED ULTRADIAN RHYTHMS OF THE RIGHT AND LEFT BRAIN: TEMPORAL VARIATIONS OF TACTILE DISCRIMINATION TESTED IN GERMAN SUBJECTS
Authors: MEIER-KOLL ALFRED
Published: July 2002

Endogenous ultradian rhythms with a periodicity of 2–3 hours operate separately in the right and left hemispheres of the human brain and modulate physiological functions, perception and cognition. Since sensory pathways from either hand terminate in the contralateral hemisphere, ultradian rhythms of the right and left brain can be monitored by variations in the tactile discrimination of the left and right hand, respectively. Thirteen right-handed German males were tested every 15 minutes for 8 hours. Time series of the tactile error rate determined for the right and left hands oscillate with significantly different ultradian periodicities. Whereas cycles in tactile discrimination of the right hand (left hemisphere) have a periodicity of about 2 hours, tactile discrimination of the left hand (right hemisphere) is modulated by longer periods of about 3 hours. This is interpreted in terms of the overall functional asymmetry of the human brain. Since the left brain is the specialized locus for verbal processing and the right brain for visual–spatial processing, lateralized ultradian rhythms operating in the hemispheres may provide a distinct frame for long-term timing of neuronal processes underlying semantic and spatial mapping of the environment. This is particularly important for interpreting biosocial behavioural rhythms seen in humans living under natural conditions.
Qualitative and quantitative analysis of phosphorylated compounds in milk by means of 31P-NMR
Authors: BELLOQUE JOSEFINA , DE LA FUENTE MIGUEL ANGEL , RAMOS MERCEDES
Published: July 2002

31P-NMR has been tested as a technique for determining the phosphorus
content of milk samples in both the inorganic form (Pi) and bonded to caseins as
phosphoserine (SerP). 31P-NMR made possible the simultaneous determination of Pi
and SerP in ∼ 1·7 h. The determination is based on measuring the area under the
resonance in question and interpolating in a calibration curve prepared using
external standards of known phosphorus contents and prepared in the same manner.
The concentration–area plots obtained were linear in the ranges 162–1993 mg P/l for
Pi and 38–402 mg P/l for casein SerP. The repeatability of the method was good.
When the same milk samples were analysed by both 31P-NMR and the classic
colorimetric method the correlation was good. Polyphosphates added to commercial
milk were also detected, as diphosphates. The NMR response for diphosphate was
linear between 58 and 576 mg P/l and preliminary results indicated that quantitative
analysis could be achieved in commercial milk.
Proteolysis and its role in relation to texture of Feta cheese made
from ultrafiltered milk with different amounts of rennet
Authors: WIUM HELLE , KRISTIANSEN KRISTIAN R. , QVIST KARSTEN B.
Published: July 2002

The relationship between proteolysis and texture in Feta-type cheese
made from ultrafiltered cows' milk was studied using capillary electrophoresis,
chemical analysis and uniaxial compression. For this purpose cheeses were
made
with almost identical gross chemical compositions, but wide variations
in texture,
obtained by varying the amount of rennet and the coagulation conditions.
αs1-Casein
(CN) 8P, αs1-CN 9P and αs1-CN 8P-I
were degraded during ripening, while β-CN A1,
β-CN A2 and para-κ-CN were slightly
degraded at the highest rennet additions and
longest storage time tested (39 weeks). αs1-CN 8P,
αs1-CN 9P and αs1-CN 8P-I were
degraded even in cheeses made without rennet, and this was ascribed to
cathepsin D
activity. αs1-CN 9P disappeared faster than αs1-CN
8P,
which suggests that milk acid phosphatase was active during storage. During
ripening,
stress at fracture (σf), strain
at fracture (εf), the deformability modulus (E)
and work to fracture (Wf) all
decreased. Since the gross chemical composition was essentially constant
during
storage, these changes could be ascribed purely to proteolysis. Although
εf could be
predicted fairly well from capillary electrophoresis results (correlation
coefficient
0·85), there were no unique relationships between degradation of
casein components
and σf when both storage time and the amount of rennet
used were varied. In the
young cheese a high level of proteolysis could coexist with high values
of σf. This
suggests that high levels of rennet caused σf to increase,
via an effect unrelated to
general proteolysis, whereas general proteolysis caused the reverse effect.
Effects of dietary protein supply on caseins, whey proteins,
proteolysis and renneting properties in milk from cows grazing
clover or N fertilized grass
Authors: HERMANSEN JOHN E. , OSTERSEN STEEN , JUSTESEN NIELS C. , AAES OLE
Published: July 2002

The objective of this work was to examine whether variation in the amino
acid supply to cows could be a reason for the reduced casein content and poorer
renneting properties of milk that often occur in late summer, or whether these effects
are related to proteolysis in the raw milk. In a 2×2×2 factorial design, we
investigated the effects of sward (clover v. rye-grass) and supplementary feed with a
high or low level of rumen-soluble N or of rumen undegradable protein on milk
protein composition during the grazing season. A total of 32 Danish Holstein cows
were included in the experiment. Milk protein and casein contents and the ratios
casein N[ratio ]total N and casein[ratio ]true protein were at a minimum in late summer,
whereas the contents of urea, non-protein N and whey protein were higher during
this period. These seasonal effects were unrelated to either the type of supplementary
feed or the type of sward; neither were they clearly related to proteolysis, although
casein[ratio ]true protein was related to the proteose peptone content. The results
indicated that whey proteins other than α-lactalbumin or β-lactoglobulin accounted
for the higher proportion or concentration of whey protein in late summer. Based on
a principal component analysis including variables such as citric acid, lactose and
non-protein N, we suggest that the cows' energy supply during this period may be
a critical factor in determining the milk protein composition, although our results
were not conclusive. There was an interaction between the supplement of rumen
undegradable protein and type of sward. When clover was grazed, a high supplement
increased the concentrations of protein and casein in milk and the κ-casein[ratio ]total
casein ratio. When rye-grass was grazed, the opposite response was found, and
overall milk protein yield was not affected. The very low N content of clover in early
summer reduced milk protein and casein protein during this period.
Purification of goat β-lactoglobulin from whey by an ultrafiltration
membrane enzymic reactor
Authors: SANNIER FRÉDÉRIC , BORDENAVE STÉPHANIE , PIOT JEAN-MARIE
Published: July 2002

This paper presents a novel contribution to the purification of goat
β-lactoglobulin by using an ultrafiltration membrane enzymic reactor. The basis of
the purification process was the enzymic hydrolysis of contaminating proteins,
α-lactalbumin and traces of serum albumin, by pepsin at 40 °C and pH 2, conditions
under which β-lactoglobulin is resistant to peptic digestion. Simultaneously,
β-lactoglobulin and peptides were separated by ultrafiltration. β-Lactoglobulin was
retained in the reactor while peptides generated by hydrolysis from α-lactalbumin
and serum albumin permeated through the membrane. The process was made
continuous by the addition of fresh whey to replace the lost permeate. Three mineral
membranes with 10, 30 and 50 kDa molecular mass cut-off were tested and the
30 kDa membrane was selected for the continuous process. The simultaneous
purification and concentration of β-lactoglobulin from clarified goats' whey was
achieved in a single step. The ultrafiltration membrane enzymic reactor could treat
eight reactor volumes of clarified whey. The recovery of β-lactoglobulin was 74%, its
purity was 84% and its concentration 6·6-fold that in the initial clarified whey.
German Free Churches and the Nazi Regime
Authors: RAILTON NICHOLAS M.
Published: July 2002

There are a number of excellent studies on the
Protestant Churches
in the Third Reich, but none contains a thorough treatment of the
smaller Free Churches. Ernst Christian Helmreich included a
short chapter on these in his 1979 work on The German Churches
under Hitler: background, struggle and epilogue.
The recent publication of a work by
Andrea Strübind on the German Baptist Churches,
Die unfreie Freikirche: der Bund der Baptistengemeinden
im Dritten Reich (1995), and by Herbert
Strahm on the Episcopal Methodist Church, Die
Bischöfliche Methodistenkirche im Dritten Reich (1989),
should encourage research on a topic that
has been badly neglected in the past.

This article seeks to shed light on the relationship of German
evangelicalism as embodied in the Free Churches to the mainline
provincial churches as well as to the regime of National
Socialism. It will show that evangelicals were actually far
less united than is generally perceived to be the case.
Northern Italian Confraternities and
the Immaculate Conception in the
Fourteenth Century
Authors: SELLA BARBARA
Published: July 2002

The early fourteenth century marks one of the most significant

periods in the development of the doctrine of the Immaculate
Conception. Not only did this period witness a profound
transformation in the theological understanding of the older feast of the

Conception of the Blessed Virgin Mary, but it also brought about the
active engagement of the laity in its celebration. In northern Italy the
first
lay confraternities dedicated to celebrating the feast of the Conception

were founded in the 1320s and 1330s under the direction of the
Franciscans, then the greatest advocates of the immaculist cause. This

coincidence between the theological definition of Mary's conception,
lay
participation in the feast's celebration, and Franciscan sponsorship
of
confraternities raises interesting questions about the nature of lay piety

and the role of lay associations in disseminating religious beliefs.

The question of when certain religious beliefs and their theological

formulations become known and understood by the majority of the
faithful is complex, particularly in the case of the Immaculate Conception.

No explicit mention of Mary's sinless conception exists in Scripture
or in
apostolic teaching. Belief in the Immaculate Conception emerged only
gradually, through centuries of reflection and disputation, and was not

proclaimed a dogma of faith until 1854. This gradual unfolding of the
doctrine has meant that identifying the shift from a general reverence
for
Mary's conception to an explicit belief in the sinlessness of her
conception
has proved difficult. A second difficulty is that for centuries the qualifier

‘immaculate’ was not attached to the name of the feast. During
the
Middle Ages the feast was referred to simply as the ‘Conception of
the
Blessed Virgin Mary’ The mere observance of the feast, therefore,
tells
us little about what the faithful actually believed.
Don Bosco's dreams. A historico-documentary analysis of selected samples.
By Pietro Stella, translated by John Drury (Don Bosco in the History of Catholic Religious Thought and Practice.) Pp. xvi+98. New Rochelle, NY: Salesiana, 1996
(first publ. as an appendix in Don Bosco nella storia della religiosità cattolica, II: Mentalità religiosa e spiritualità, Rome: Las-Roma, 1981). $20 (cloth), $10
(paper). 0 89944 269 2; 0 89944 270 6. Don Bosco. Religious outlook and spirituality. 2nd revised edn. By Pietro Stella
(Don Bosco in the History of Catholic Religious Thought and Practice, 2.) (Trans. by John Drury of Don Bosco nella storia della religiosità cattolica, II:
Mentalità religiosa e spiritualità, Rome: Las-Roma, 1981.) Pp. xxi+594. New
Rochelle, NY: Salesiana, 1996. $49 (cloth), $36 (paper). 0 89944 161 0;
0 89944 162 9.
Authors: Logan Oliver
Published: July 2002

Don Bosco. Life and work. 2nd revised edn. By Pietro Stella (Don Bosco in the
History of Catholic Religious Thought and Practice, 3.) (Trans. by John
Drury of Don Bosco nella storia della religiosità cattolica,
I: Vita e opere, seconda
edizione riveduta dall'autore, Rome: Las-Roma, 1979.) Pp. xxiii+305. New
Rochelle, NY: Salesiana/Don Bosco Publications, 1985. 0 89944 080 0
Persecutors, Tempters and Vassals of the Devil: The Unregenerate in
Puritan Practical Divinity
Authors: LUTTMER FRANK
Published: July 2002

During the late Tudor and early Stuart age, England's parish
ministries were increasingly occupied by energetic Puritan
preachers who sought to convert souls and build ‘godly’
communities. Together with ‘godly’ magistrates and lay supporters, these
preachers laboured to replace a culture rooted in traditional festivals, ales,
dances and games with a culture sustained by frequent sermons, Scripture-reading and a strict observance of the Sabbath. Not everyone, however,
heeded the call of the preachers. Many people, in most places probably
a significant majority, were unable or unwilling to embrace the Puritan
theology of grace and were opposed to Puritans' interference in their lives.
Resistance to Puritans surfaced in different forms and degrees, ranging
from indifference and passivity to organised demonstrations and protests,
to street fighting and violence. Verbal abuse seems to have been common;
the preferred term of abuse, ‘Puritan’, remained a potent and wounding
accusation in spite of its common currency. From about the 1570s and
80s, when Puritan evangelism emerged as a significant movement in
England, to the period of the Civil War, tensions between Puritans and
anti-Puritans periodically surfaced in towns and villages across the
kingdom, with divisions in communities cutting across class lines.
Evolution of a nonlinear wave field along a tank: experiments and numerical simulations based on the spatial Zakharov equation
Authors: SHEMER L. , JIAO HAIYING , KIT E. , AGNON Y.
Published: July 2002

Evolution of a nonlinear wave field along a laboratory tank is studied experimentally
and numerically. The numerical study is based on the Zakharov nonlinear equation,
which is modified to describe slow spatial evolution of unidirectional waves as they
move along the tank. Groups with various initial shapes, amplitudes and spectral
contents are studied. It is demonstrated that the applied theoretical model, which
does not impose any constraints on the spectral width, is capable of describing
accurately, both qualitatively and quantitatively, the slow spatial variation of the
group envelopes. The theoretical model also describes accurately the variation along
the tank of the spectral shapes, including free wave components and the bound waves.
Free and forced convection around line sources of heat and heated cylinders in porous media
Authors: KURDYUMOV VADIM N. , LIÑÁN AMABLE
Published: July 2002

An analysis is presented for the steady, two-dimensional, free convection around line
sources of heat and heated cylinders in unbounded saturated porous media. It is
extended to account also for the effects of forced convection. The study is based on
the Boussinesq equations, with the velocities calculated using Darcy's law.

The analysis begins with the non-dimensional formulation and numerical solution
of the problem of pure free convection around a line source of heat. When this
analysis is extended to include the effects of forced convection, two parameters
appear in the non-dimensional formulation: the non-dimensional value, V∞, of the
free-stream velocity and its angle γ of inclination with respect to the vertical. We
first describe the asymptotic form of the solution for large and small values of the
distance to the source. The far-field description, which is also applicable to the flow
around heated cylinders, is needed to facilitate the numerical solution of the problem.
It includes a thermal wake, aligned with the free stream, and an outer irrotational
flow with a sink and a vortex at the line source. The temperature distribution near
the source involves a constant A0(V∞, γ), to be calculated with
the numerical solution of the complete problem, which is used in the evaluation of the heat transfer from
heated cylinders when the Rayleigh and Péclet numbers are small compared with
unity. In this case we find an inner region where heat conduction is dominant, and
an outer region where the cylinder appears as a line source of heat. The asymptotic
analysis is complemented with the numerical solution of the general problem for
circular cylinders with a wide range of Rayleigh numbers and some representative
values of V∞ and γ. We give correlations for the Nusselt number in the limiting cases
of pure free convection and pure forced convection.
A model for vortex ring formation in a starting buoyant plume
Authors: SHUSSER MICHAEL , GHARIB MORTEZA
Published: July 2002

Vortex ring formation in a starting axisymmetric buoyant plume is considered. A
model describing the process is proposed and a physical explanation based on the
Kelvin–Benjamin variational principle for steady vortex rings is provided. It is shown
that Lundgren et al.'s (1992) time scale, the ratio of the velocity of a buoyant plume
after it has travelled one diameter to its diameter, is equivalent to the time scale
(formation time) proposed by Gharib et al. (1998) for uniform-density vortex rings
generated with a piston/cylinder arrangement. It is also shown that, similarly to
piston-generated vortex rings (Gharib et al. 1998), the buoyant vortex ring pinches
off from the plume when the latter can no longer provide the energy required for
steady vortex ring existence. The dimensionless time of the pinch-off (the formation
number) can be reasonably well predicted by assuming that at pinch-of the vortex
ring propagation velocity exceeds the plume velocity. The predictions of the model
are compared with available experimental results.
Inertial effects in three-dimensional spinodal decomposition of a symmetric binary fluid mixture: a lattice Boltzmann study
Authors: KENDON VIVIEN M. , CATES MICHAEL E. , PAGONABARRAGA IGNACIO , DESPLAT J.-C. , BLADON PETER
Published: July 2002

The late-stage demixing following spinodal decomposition of a three-dimensional
symmetric binary fluid mixture is studied numerically, using a thermodynamically
consistent lattice Boltzmann method. We combine results from simulations with
different numerical parameters to obtain an unprecedented range of length and time
scales when expressed in reduced physical units. (These are the length and time units
derived from fluid density, viscosity, and interfacial tension.) Using eight large (2563)
runs, the resulting composite graph of reduced domain size l against reduced time
t covers 1 [lsim ] l [lsim ] 105, 10 [lsim ] t [lsim ] 108.
Our data are consistent with the dynamical
scaling hypothesis that l(t) is a universal scaling curve. We give the first detailed
statistical analysis of fluid motion, rather than just domain evolution, in simulations
of this kind, and introduce scaling plots for several quantities derived from the fluid
velocity and velocity gradient fields. Using the conventional definition of Reynolds
number for this problem, Reϕ = ldl/dt,
we attain values approaching 350. At Reϕ [gsim ] 100 (which requires
t [gsim ] 106) we find clear evidence of Furukawa's inertial
scaling (l ∼ t2/3), although the crossover from the viscous regime
(l ∼ t) is both broad and late (102 [lsim ] t [lsim ] 106).
Though it cannot be ruled out, we find no indication that Reϕ is self-limiting
(l ∼ t1/2) at late times, as recently proposed by Grant & Elder.
Detailed study of the velocity fields confirms that, for our most inertial runs, the RMS
ratio of nonlinear to viscous terms in the Navier–Stokes equation, R2, is of order
10, with the fluid mixture showing incipient turbulent characteristics. However, we
cannot go far enough into the inertial regime to obtain a clear length separation of
domain size, Taylor microscale, and Kolmogorov scale, as would be needed to test
a recent ‘extended’ scaling theory of Kendon (in which R2 is self-limiting but
Reϕ not). Obtaining our results has required careful steering of several numerical control
parameters so as to maintain adequate algorithmic stability, efficiency and isotropy,
while eliminating unwanted residual diffusion. (We argue that the latter affects some
studies in the literature which report l ∼ t2/3 for
t [lsim ] 104.) We analyse the various
sources of error and find them just within acceptable levels (a few percent each) in
most of our datasets. To bring these under significantly better control, or to go much
further into the inertial regime, would require much larger computational resources
and/or a breakthrough in algorithm design.
Flow in two-sided lid-driven cavities:

non-uniqueness, instabilities, and cellular structures
Authors: KUHLMANN H. C. , WANSCHURA M. , RATH H. J.
Published: July 2002

The steady flow in rectangular cavities is investigated both numerically

and experimentally. The flow is driven by moving two facing walls tangentially
in

opposite

directions. It is found that the basic two-dimensional flow is not always
unique. For

low Reynolds numbers it consists of two separate co-rotating vortices adjacent
to the

moving walls. If the difference in the sidewall Reynolds numbers is large
this flow

becomes unstable to a stationary three-dimensional mode with a long wavelength.

When the aspect ratio is larger than two and both Reynolds numbers are
large, but

comparable in magnitude, a second two-dimensional flow exists. It takes
the form

of a single vortex occupying the whole cavity. This flow is the preferred
state

in the

present experiment. It becomes unstable to a three-dimensional mode that
subdivides

the basic streched vortex flow into rectangular convective cells. The instability
is

supercritical when both sidewall Reynolds numbers are the same. When they
differ

the instability is subcritical. From an energy analysis and from the salient

features

of the three-dimensional flow it is concluded that the mechanism of destabilization

is identical to the destabilization mechanism operative in the elliptical

instability of highly strained vortices.
Propagation of strongly nonlinear plane N-waves
Authors: INOUE YOSHINORI , YANO TAKERU
Published: July 2002

Formation and evolution of N (-like) waves is studied

without the restriction of low

amplitude, namely weak nonlinearity. To this end, the classical piston
problem of

gasdynamics is investigated, in which the wave is radiated by a piston
executing a

single cycle of harmonic oscillation into an inviscid perfect gas.

The method of analysis

is based on the simple-wave theory up to the shock formation time, and
beyond that

time on the numerical calculation by a high-resolution TVD upwind scheme.
The

initial sinusoid-like wave profile is rapidly distorted as the wave

propagates, and this

leads to the formation of head and tail shocks. The main effects of

strong nonlinearity

may be listed as follows: (i) entropy production at shock fronts, (ii)

the existence of

waves reflected from shocks, (iii) an asymmetric wave profile stemming
from the

boundary condition at the source of the strongly nonlinear problem. As
the result,

the strongly nonlinear wave possesses the following remarkable distinctive
features,

in contrast to its counterpart in the weakly nonlinear regime. The tail
shock is not

formed at the tail of the wave, and the expansion wave behind the head
shock

has non-uniform intensity. The N (-like) wave propagates

with some excess mass.

Thereby a region with low density, associated with the entropy production,
appears

in the vicinity of the source.
Spatio–temporal instability in
mixed convection boundary layers
Authors: MORESCO P. , HEALEY J. J.
Published: July 2002

In this work we analyse the stability properties of the flow over an isothermal,
semi-infinite vertical plate, placed at zero incidence to an otherwise uniform stream
at a different temperature. Near the leading edge the boundary layer resembles
Blasius flow, but further downstream it approaches that of pure buoyancy-driven
flow. A coordinate transformation that describes in a smooth way the evolution
between these two limiting similarity states, where the viscous and buoyancy forces are
respectively dominant, is used to calculate the basic flow. The stability of this flow has
been investigated by making the parallel flow approximation, and using an accurate
spectral method on the resulting stability equations. We show how the stability modes
discussed by other authors can be followed continuously between the forced and free
convection limits; in addition, new instability modes not previously reported in the
literature have been found. A spatio–temporal stability analysis of these modes has
been carried out to distinguish between absolute and convective instabilities. It seems
that absolute instability can only occur when buoyancy forces are opposed to the free
stream and when there is a region of reverse flow. Model profiles have been used in
this latter case beyond the point of boundary layer separation to estimate the range
of reverse flows that support absolute instability. Analysis of the Rayleigh equations
for this problem suggests that the absolute instability has an inviscid origin.
Stability boundaries of roll and square
convection in binary fluid mixtures with positive
separation ratio
Authors: HUKE B. , LÜCKE M. , BÜCHEL P. , JUNG CH.
Published: July 2002

Rayleigh–Bénard convection in horizontal layers of binary fluid mixtures heated from
below with realistic horizontal boundary conditions is studied theoretically using
multi-mode Galerkin expansions. For positive separation ratios the main difference
between the mixtures and pure fluids lies in the existence of stable three-dimensional
patterns near onset in a wide range of the parameter space. We evaluated the
stationary solutions of roll, crossroll, and square convection and we determined
the location of the stability boundaries for many parameter combinations thereby
obtaining the Busse balloon for roll and square patterns.
Intermittent mixing in strongly stratified fluids as a random walk
Authors: VANNESTE J. , HAYNES P. H.
Published: July 2002

In strongly stratified geophysical fluids such as the stratosphere and the ocean, the
vertical mixing of tracers is largely due to patches of turbulence that are intermittent
in time and space. Heuristic models for this type of mixing are studied which
extend that of Dewan (1981a). The recognition that, in these models, fluid particles
undergo continuous-time random walks allows the derivation of closed-form results
for the particle-position statistics. The particle dispersion is shown generally to be
diffusive in the long-time limit. However, the early-time, non-diffusive regime is also
analysed, since a time-scale estimate indicates its practical importance, in particular
for stratospheric mixing.

Because the restratification of fluid patches previously homogenized by turbulence
takes a finite time, the probability for a fluid region to become turbulent may depend
on the time elapsed since it has last been turbulent. This introduces a ‘memory
effect’ whose consequences for the tracer mixing are analysed in detail using a simple
non-Markovian model.

The heuristic models studied allow the large-scale dispersive effects of the turbulent
patches to be inferred from the properties of individual patches. This highlights those
properties that might most usefully be determined from investigations of the dynamics
of the turbulent patches themselves.
Elections and Political Participation in Nineteenth-Century Peru: The 1871–72 Presidential Campaign
Authors: MÜCKE ULRICH
Published: July 2002

This article examines the relationship between elections and political
participation in nineteenth-century Peru. Focusing on the elections of 1871–72,
I argue that for a better understanding of the way elections facilitated political
participation, we should consider not only the vote itself but also analyse the
extensive electoral campaign. Generally, voting was irregular, as the different
political factions attempted to impede the participation of their opponents
through violence. To win the violent clashes on election day it was necessary to
mobilise the popular classes. Especially in the cities, corruption and patron–client
ties alone proved to be insufficient to gain support. To build powerful political
factions, candidates had to win public opinion through massive campaigning and
they had to respond to the claims of the urban middle and lower classes. All
factions engaged in electoral fraud and neither the government nor any other
political actor could determine the electoral outcome. Strong political factions
were able to counterbalance governmental interference. That is why, in 1872, a
government-opposed candidate, Manuel Pardo, was able to win the presidential
election.
Indicators and procedures: nevertheless and but
Authors: BLAKEMORE DIANE
Published: July 2002

The paper aims to clarify the Relevance theoretic notion of procedural meaning (cf.
Blakemore 1987, Wilson & Sperber 1993) through the analysis of but and nevertheless.
I show, first, that a procedural analysis is able to account for differences between
these expressions that cannot be explained in terms of the speech-act theoretic notion
of non-truth conditional indicators, and, second, that these differences show that the
conception of procedural meaning as a constraint on contextual effects (cf. Blakemore
1987) is too narrow and must be extended to include all information about the
inferential processes involved in utterance interpretation, including context selection.
Rural poverty and poverty alleviation in Mozambique: what's
missing from the debate?
Authors: Cramer Christopher , Pontara Nicola
Published: July 2002

The peace accord signed in October 1992 and multiparty elections
held
in October 1994 brought to Mozambique fresh hopes and opportunities.
Post-war reconstruction has been underway for some years,
through an array of projects ranging from hand-outs for demobilised
soldiers to the World Bank supported Roads and Coastal Shipping
(ROCS) rehabilitation project running from 1994 to 2000. Although
there is political tension between the two main parties and former
contestants in the civil war, Frelimo and Renamo, and a combination
of rising urban crime and sporadic banditry on roads in rural areas,
generally there has been a strong improvement in political stability and

physical security for the majority of the population. Economic reforms,

broadly typical of World Bank/IMF stabilisation and structural
adjustment programmes, have accelerated during the 1990s and have
been underwritten by substantial external financial support. The end
of war together with deregulating policy reforms and a sweeping
privatisation programme have provoked a surge in foreign investor
interest in the country. In aggregate terms and in spite of data caveats,

the evidence suggests that Mozambique has become one of the fastest
growing economies in Sub-Saharan Africa during the 1990s.
The evolution of magnetic flux ropes in sheared plasma flows
Authors: SCHMIDT J. M. , CARGILL P. J.
Published: July 2002

The evolution of magnetic flux ropes in a sheared plasma flow is investigated.
When the magnetic field outside the flux rope lies parallel to the axis of
the flux rope, a flux rope of circular cross-section, whose centre is located at the
midpoint of the shear layer, has its shape distorted, but remains in the shear layer.
Small displacements of the flux-rope centre above or below the midpoint of the shear
layer lead to the flux-rope being expelled from the shear layer. This motion arises
because small asymmetries in the plasma pressure around the flux-rope boundary
leads to a force that forces the flux rope into a region of uniform flow. When the
magnetic field outside the flux rope lies in a plane perpendicular to the flux-rope
axis, the flux rope and external magnetic field reconnect with each other, leading
to the destruction of the flux rope.
A general theory of self-similar expansion
waves in magnetohydrodynamic flows
Authors: TAYLOR M. G. G. T. , CARGILL P. J.
Published: July 2002

Abstract. The general theory of self-similar magnetohydrodynamic (MHD) expansion
waves is presented. Building on the familiar hydrodynamic results, a complete
range of possible field–flow and wave-mode orientations are explored. When the
magnetic field and flow are parallel, only the fast-mode wave can undergo an expansion
to vacuum conditions: the self-similar slow-mode wave has a density that
increases monotonically. For fast-mode waves with the field at an arbitrary angle
with respect to the flow, the MHD equations have a critical point. There is a unique
solution that passes through the critical point that has ½γβ = 1 and Br = 0 there,
where γ is the polytropic index, β the local plasma beta and Br the radial component
of the magnetic field. The critical point is an umbilical point, where sound and
Alfvén speeds are equal, and the transcritical solution undergoes a change from a
fast-mode to a slow-mode expansion at the critical point. Slow-mode expansions
exist for field-flow orientations where the angle between field and flow lies either
between 90° and 180° or between 270° and 360°. There is also an umbilic point
in these solutions when the initial plasma beta β0 exceeds a critical value βcrit.
When β0 [ges ] βcrit, the solutions require a transition through a critical point. When
β0 < βcrit, there is a smooth solution involving an inflection in the density and
angular velocity. For other angles between field and flow, all the slow-mode waves
are compressive. An analytic solution for the case of a magnetic field everywhere
perpendicular to the flow with γ = 2 is presented.