bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental evolution in Heterandria formosa, a livebearing fish: group selection on population size
Authors: BAER CHARLES F. , TRAVIS JOSEPH , HIGGINS KEVIN
Published: July 2002

Group selection has historically been an important and controversial subject in evolutionary
biology. There is now a compelling body of evidence, both theoretical and experimental, that
group selection not only can be effective, but can be effective in situations when individual
selection is not. However, experiments in which true population-level traits have been shown to
evolve in response to group selection are currently limited to two species of flour beetle in the
genus Tribolium and RNA viruses. Here we report the results of an experiment wherein we
imposed group selection via differential extinction for increased and decreased population size at
6-week intervals, a true population-level trait, in the poeciliid fish Heterandria formosa. In contrast
to most other group selection experiments, we observed no evolutionary response after six rounds
of group selection in either the up- or down-selected lines. Populational heritability for population
size was low, if not actually negative. Our results suggest that group selection via differential
extinction may be effective only if population sizes are very small and/or migration rates are low.
Inferring the trajectory of genetic variance in the course of artificial selection
Authors: SORENSEN D. , FERNANDO R. , GIANOLA D.
Published: July 2002

A method is proposed to infer genetic parameters within a cohort, using data from all individuals
in an experiment. An application is the study of changes in additive genetic variance over
generations, employing data from all generations. Inferences about the genetic variance in a given
generation are based on its marginal posterior distribution, estimated via Markov chain Monte
Carlo methods. As defined, the additive genetic variance within the group is directly related to the
amount of selection response to be expected if parents are chosen within the group. Results from a
simulated selection experiment are used to illustrate properties of the method. Four sets of data
are analysed: directional selection with and without environmental trend, and random selection,
with and without environmental trend. In all cases, posterior credibility intervals of size 95%
assign relatively high density to values of the additive genetic variance and heritability in the
neighbourhood of the true values. Properties and generalizations of the method are discussed.
Cloning of two Bombyx homologues of the Drosophila rosy

gene and their relationship to larval translucent skin colour mutants
Authors: YASUKOCHI YUJI , KANDA TOSHIO , TAMURA TOSHIKI
Published: July 2002

To clone the Bombyx xanthine dehydrogenase (XDH) gene

as a dominant marker for silkworm
transgenesis, we performed nested reverse transcriptase–polymerase

chain reaction (RT-PCR) using
embryonic mRNA and primers designed from the conserved region of Drosophila and rat XDH
genes. Sequencing of amplified 180 bp fragments showed that two different

sequences were present
in the fragments. Since both possessed striking similarity to XDH genes
of other organisms, we
considered these to be portions of silkworm XDH genes and designated them
BmXDH1 and
BmXDH2. Subsequently we cloned separately the entire region of the two
cDNAs by PCR using
phage DNA of an embryonic cDNA library and sequenced them. The two cDNAs
were around
4 kb in size and possessed complete open reading frames. The deduced amino
acid sequences of
the two BmXDHs were very similar to each other and to those of other organisms.
The expression
pattern of wild-type larvae basically followed the tissue specificity
of the enzyme and no significant
difference was observed between the two XDH genes. The expression of both
genes was detected in
the XDH-deficient mutants, oq and og, but non-synonymous

substitutions were specifically
detected in the BmXDH1 of the oq mutant. In addition, a length

polymorphism of the second
intron of the BmXDH1 co-segregated with the oq translucent
phenotype, suggesting that deficiency
in BmXDH1 is the cause of the oq translucent phenotype.
Identification of possible quantitative trait loci responsible
for hyperglycaemia after 70% pancreatectomy using a
spontaneously diabetogenic rat
Authors: OGINO T. , MORALEJO D. H. , ZHU M. , TOIDE K. , WEI S. , WEI K. , YAMADA T. , MIZUNO A. , MATSUMOTO K. , SHIMA K.
Published: July 2002

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal
model for obese-type non-insulin-dependent diabetes mellitus (NIDDM) in humans. The OLETF rat exhibits
sustained
hyperglycaemia after partial pancreatectomy, while the normal control rat
does not. This difference
is thought to be genetically determined and to be caused by impairment
of β-cell regrowth, a
possible event involved in the pathogenesis of NIDDM. Our investigation
was designed to identify
quantitative trait loci (QTL) responsible for post-pancreatectomy hyperglycaemia
by performing a
genome-wide scan in an F2 intercross obtained by mating the
OLETF and Fischer-344 (F344) rats.
We have identified three possible QTL on rat chromosomes (Chrs) 3, 14 and
19 that account for a
total of approximately 75% of the genetic variance in the F2.
For the QTL on Chr 14, the
OLETF allele corresponds with increased glucose levels, as expected. Surprisingly,
for the QTL on
Chr 19, the F344 allele corresponds with increased glucose levels. The
Chr 3 QTL exhibits
heterosis, heterozygotes showing significantly higher glucose levels than
OLETF or F344
homozygotes. We also found evidence for interaction (epistasis) between
the QTL on Chrs 14 and
19.
The great-grand-daughter design: a simple strategy to
increase the power of a grand-daughter design for QTL mapping
Authors: COPPIETERS WOUTER , KVASZ ALEXANDRE , ARRANZ JUAN-JOSÉ , GRISART BERNARD , RIQUET JULIETTE , FARNIR FRÉDÉRIC , GEORGES MICHEL
Published: July 2002

In dairy cattle, quantitative trait loci (QTL) are usually mapped using the grand-daughter design
(GDD), i.e. sets of progeny-tested paternal half-brothers. Linkage information is typically
extracted from the segregation of the sire chromosomes amongst their sons. We herein propose to
increase the power of a GDD by exploiting the frequently occurring relationship between sires and
grandsons which has so far been ignored in most methods of analysis. The proposed approach is a
multipoint interval mapping method based on the Wilcoxon sum-of-rank test. Three alternative
approaches to combine information from sons and grandsons are evaluated by simulation. In these
either (i) sons and grandsons are ranked separately, (ii) sons and grandsons are ranked separately
but the sign of the QTL effect is constrained to be the same in both generations, or (iii) sons and
grandsons are ranked jointly. The proposed methods have been applied on a real data-set in which
a GDD including 907 sons is analysed with a marker map comprising nine microsatellites spanning
46 cM on bovine chromosome 6.
Estimating genetic correlations in natural populations
Authors: LYNCH MICHAEL
Published: July 2002

Information on the genetic correlation between traits provides fundamental insight into the
constraints on the evolutionary process. Estimates of such correlations are conventionally obtained
by raising individuals of known relatedness in artificial environments. However, many species are
not readily amenable to controlled breeding programmes, and considerable uncertainty exists over
the extent to which estimates derived under benign laboratory conditions reflect the properties of
populations in natural settings. Here, non-invasive methods that allow the estimation of genetic
correlations from phenotypic measurements derived from individuals of unknown relatedness are
introduced. Like the conventional approach, these methods demand large sample sizes in order to
yield reasonably precise estimates, and special precautions need to be taken to eliminate bias from
shared environmental effects. Provided the sample consists of at least 20% or so relatives,
informative estimates of the genetic correlation are obtainable with sample sizes of several hundred
individuals, particularly if supplemental information on relatedness is available from polymorphic
molecular markers.
REVISING THE HOLOCAUST
Authors: BIRN RUTH BETTINA
Published: July 2002

Hitler's willing executioners. Ordinary Germans and the

Holocaust. By Daniel Jonah

Goldhagen. London: Little Brown and Company, 1996. Pp. x+622. £20.

Questions about the motives of the perpetrators and, by implication,

the causes of the

Holocaust, have long been in the forefront of academic or non-academic
discussions

of the Nazi period – from the time of contemporary observers to

the present day. A wide

range of possible responses to these questions has been put forward, drawing
on

concepts from a variety of disciplines, such as history, psychology, sociology
or

theology. Daniel Goldhagen's book on the motivation of the perpetrators
of the

Holocaust claims to be a ‘radical revision of what has until now
been

written’ (p. 9).

This claim is made on the book-jacket and by the author himself. His thesis
can be

summarized as follows: Germany was permeated by a particularly radical
and vicious

brand of anti-Semitism whose aim was the elimination of Jews. The author
defines this

as ‘eliminationist anti-Semitism’. This viral strain of

anti-semitism, he states, ‘resided

ultimately in the heart of German political culture, in German society

itself’ (p. 428).

Medieval anti-Semitism, based as it was on the teachings of the

Christian religion, was

so ‘integral to German culture’ (p. 55) that with the

emergence of the modern era it

did not disappear but rather took on new forms of expression, in particular,
racial

aspects. By the end of the nineteenth century ‘eliminationist

anti-Semitism’ dominated

the German political scene. In the Weimar Republic, it grew more

virulent even before

Hitler came to power. The Nazi machine merely turned this ideology into
a reality.

The course of its actualization was not deterred by anything save

bare necessity: ‘the

road to Auschwitz was not twisted’ (p. 425). When the

‘genocidal program’ was

implemented along with the German attack on the Soviet Union, it was supported
by

the general German population, by the ‘ordinary Germans’

– the key phrase of the

book – who became ‘willing executioners’. They had

no need of special orders,

coercion or pressure because their ‘cognitive model’

showed them that Jews were

‘ultimately fit only to suffer and to die’ (p. 316).
SETA B. DADOYAN, The Fatimid Armenians: Cultural and Political Interaction in the Near East, Islamic History and Civilization: Studies and Texts, vol. 18, ed. Ulrich Haarmann and Wadad Kadi (Leiden: E. J. Brill, 1997). Pp. 222. $72.00 cloth.
Authors: Franz-Murphy Gladys
Published: July 2002

Rather than expound a thesis, this study establishes the fundamental facts of Armenian history from the 4th century to the 12th century on the basis of multiple difficult and sometimes hitherto unexploited sources. If there is an overall thesis, it is that Armenian sectarianism was so prevalent that it accounts for the fragmentary picture of Armenian history given by any single source. Orthodox Armenian sources ignore or dismiss sectarians. Sectarians wrote no history. And Arab historians make only annalistic references to Armenians, unaware of their sectarian divisions.
ENDRE STIANSEN AND MICHAEL KEVANE, ED., Kordofan Invaded: Peripheral Incorporation and Social Transformation in Islamic Africa (Boston: Brill, 1998). Pp. 319. $94 cloth.
Authors: Lobban Richard
Published: July 2002

The history of Sudan still reflects the country's struggle to find its identity between Middle Eastern and African studies. Even within Sudan, there are spheres of interest ranging from the expanding ancient studies of Nubia to the protracted conflict between so-called Afro-Arab northerners and Nilotic southerners. Lost in these expanding domains are the histories of eastern Sudan and Kordofan to the west. Even the historiography of Sennar and Darfur is far better established than that of Kordofan. Thus, the very title of the book being reviewed suggests that Kordofan is an “invaded” and “peripheral” area on the edge of the Islamic and African worlds. Thus, this work is a welcome starting point in filling in this considerable gap in Sudan studies. Stiansen and Kevane have done noble service in this respect.
THE OTTOMAN ALGERIAN ELITE AND ITS IDEOLOGY
Authors: Shuval Tal
Published: July 2002

By the late seventeenth century, Algeria and Tunisia had established regimes that were largely independent of Ottoman sovereignty in almost every regard, although the Porte continued, in strictly legal terms, to exert minimal rights of sovereignty.

        Michel Le Gall1

But, let there be no mistake: the more a regency of Barbary has become fearsome to the Christian princes, the more the Sultan is its absolute master. He had only to utter a word to end an unjust war and fix even the terms for peace.

        Jean-Michel Venture de Paradis2

Separated by two centuries, these two quotations describe the role of the Ottoman Empire in North Africa in very different—indeed, contradictory—terms. On the one hand, Ottoman North Africa is depicted as a region where independent political entities emerged out of a century of Ottoman rule, ready as it were for the eventual emergence of nation-states in the 20th century. Venture de Paradis's earlier description, however, is devoid of the hindsight gained by our knowledge of the “end of the story.” It tells us that by the end of the 18th century, contrary to the contemporary accepted view of the remoteness of the Maghribi “regencies” from the imperial center in Istanbul, the three Ottoman provinces of North Africa were indeed an integral part of the Ottoman Empire, and the rulers of these provinces were obedient subjects of the Sublime Porte.
Industrial Labour in Post-Colonial India. I: Industrializing the Economy and Formalizing Labour
Authors: Breman Jan
Published: July 2002

In post-colonial India labour was given the connotation of work in industry. The labourer as a social figure became linked to the modern economy, a direction in which Indian society was to develop at a rapid rate. The agrarian–rural mode of life and work would soon fade away to be replaced by an industrial-urban order. The close association of labour economics with industrial employment was a logical consequence of this restructuring. The expectation of the transformation that was going to take place makes it understandable why authors of authoritative textbooks on the shape of the working class and the trade union movement were able more or less to ignore the non-industrial way of life of the large majority of the working population.
WANDALÁA sources Politik zwischen den Zeilen: Arabische Handschriften der

Wandalá in Nordkamerun. By HERMANN

FORKL, with the co-operation of REINHARD

WEIPERT. Berlin: Klaus Schwarz Verlag, 1995. Pp. 559. No

price given (ISBN 3-87997-245-1).
Authors: SPAULDING JAY
Published: July 2002

The Wandalá community of northern Cameroon and

adjoining portions of north-eastern Nigeria have a long tradition of

state forms of government. In recent centuries, following conversion

to Islam, they have composed an historiography in Arabic, an effort

entailing the adaptation of alien characters to the names and titles

of a language whose sound system differs considerably from the one for

which the symbols were originally intended. Some individual examples

of this literature have already been published, at least in

translation, but with widely varying degrees of formality and

precision. The volume reviewed here offers a critical edition and an

accurate, persuasively annotated translation of all seventeen known

Wandalá historical manuscripts in Arabic. Nine of the

manuscripts are state chronicles that convey greater or lesser amounts

of historical information arranged according to the remembered

sequence of Wandalá monarchs. One composition is a dramatic

patriotic epic, probably attributable to the days of the intrusive

eastern warlord Rabih Fadl Allah at the dawn of the present century

but couched in the form of a narrative of the defense of the

Wandalá kingdom against an eighteenth-century invasion from

Borno. Four documents are lists of local authorities at the

south-eastern town of Mime. Two manuscripts list title officials of

the central court together with some of their duties, while a third

describes some of the tax obligations incumbent upon various groups of

subjects.
SORTING OUT THE TRIBES: THE CREATION OF RACIAL IDENTITIES IN COLONIAL ZANZIBAR'S NEWSPAPER WARS
Authors: GLASSMAN JONATHON
Published: July 2002

The days are approaching when you will hear new things.
Soon you will hear that an Arab is not an Arab, a Shirazi is
not a Shirazi, and an African is not an African. You will hear
this, and you will be told that you are all Zanzibaris.

Al-Falaq, paper of the Zanzibar Arab Association, 1946

Nani awezaye kumnyoosha Binaadamu pindi alitiwa kibyongo
na Mungu? [Who can straighten out mankind, whom God has
made a hunchback?]

Afrika Kwetu, paper of the Zanzibar African Association, 1952

STUDENTS of the history of African ethnicity will recognize in the second of
these quotes a Swahili version of the aphorism from Kant with which Leroy
Vail introduces his important volume on the creation of tribalism in modern
Africa: ‘Out of the crooked timber of humanity nothing straight will ever be
fashioned’. True to their spirit, both aphorisms can be interpreted in
contradictory ways. Vail intended to point up a theme that runs throughout
his volume: that ethnic categories are rarely as clear-cut as ethnic nationalists
would have them seem, and that, where such clarity exists, it is only
momentary, having arisen out of complex and messy historical processes.
But the editors of Afrika Kwetu, the weekly newspaper of the Zanzibar
African Association that published the Swahili proverb in 1952, drew less
subtle implications. The immediate context was a plea against religious
chauvinism, part of the newspaper's allegation that Zanzibar's Arab
nationalist leaders had violated the Islamic injunction to respect other
religions ‘of the book’. But the clear implication – elsewhere made explicit –
was that God and nature had fashioned humankind into irreducibly
separate races and nations, and that it was foolish and even blasphemous to
mix or combine them, as (they charged) their Arab rivals were seeking to do.
Regulation of Rubisco activity during grain-fill in

maize: possible role of Rubisco activase
Authors: MARTÍNEZ-BARAJAS E. , MOLINA-GALÁN J. , SÁNCHEZ de JIMÉNEZ E.
Published: July 2002

Levels of ribulose bisphosphate carboxylase (Rubisco) and Rubisco

activase were compared in leaves

above the ear in two genetically related populations (Z0 and

Z20) of maize (Zea mays L.). Z20 was

obtained from Z0 after twenty agronomic selection cycles for
grain

yield improvement (c. 90% above

Z0). Plants were cultivated in the highlands of Mexico and leaves

were sampled weekly during the

grain-filling period. Chlorophyll, soluble protein and Rubisco activity
were

measured. Chlorophyll

and soluble protein content slowly decreased during this period, the former

faster than the latter, with

no significant differences between populations. During the first 40 days

after anthesis, Rubisco

activity was significantly greater in the high-yielding population

(Z20), although Western blot analysis

of Rubisco showed similar values for both populations within this period.

However, the same analysis

for Rubisco activase indicated a greater amount of this protein in the

higher-yielding population (Z20)

than the original one (Z0) during the early and middle part
of the

grain-filling period. The addition

of Rubisco activase and an ATP-generating system to Z0 leaf
extracts

resulted in increased Rubisco

activity. It was concluded that during grain-fill in maize, the level of

Rubisco activase has a regulatory effect on Rubisco activity expression.
Mid-parent advantage and heterosis in F1 hybrids of
wheat from crosses among old and modern varieties
Authors: MORGAN C. L.
Published: July 2002

Twenty-eight F1 hybrids of wheat and their parents were

grown in field trials at Trumpington,
Cambridge during 1986/87 and 1987/88. They were derived from
crosses between seven ‘modern’
varieties, used as female parents, and either two ‘old’ (Squareheads

Master and Partridge) or two
‘modern’ varieties (Bert and Motto), which were used as
male parents. Grain yield, yield
components, biomass and height were determined. The male parents were chosen
to provide
contrasting phenotypes and genetic backgrounds for the F1 hybrids.

Mid-parent advantage, the
increase of a hybrid for a given character above the mean of its parents,

and heterosis, the increase
of a hybrid above the ‘better’ parent for that character,
were calculated. Most F1 hybrids showed
mid-parent advantage for the characters studied. This tended to be
greatest for hybrids derived from
parents with the largest phenotypic differences in that character.
In contrast, where heterosis occurred
it tended to be greatest where the phenotypic difference between the
parents was least. This suggests
that the beneficial effects of hybridization, resulting from the
dispersion of dominant genes between
the parents, was insufficient to overcome the detrimental effects of
other genes present where the ‘less
good’ parent was substantially lower than the ‘better’

parent. Hybrids derived from the ‘modern’
male parents had greater heterosis for grain yield and mean grain
weight than those from the ‘old’
parents. Of the yield components, positive heterosis for mean
grain weight resulted in heavier seeds
and was the most important yield component in determining heterosis
in grain yield. Heterosis for
the number of grains/ear was small or did not differ
significantly from zero while number of ears/m2
showed negative heterosis resulting in fewer ears/m2 in
the hybrids.
Effects of shading and seed tuber spacing on
initiation and number of tubers in potato crops (Solanum tuberosum)
Authors: O'BRIEN P. J. , FIRMAN D. M. , ALLEN E. J.
Published: July 2002

Twelve field experiments, carried out over 7 years, examined
effects of shading and seed tuber spacing
on plant growth, initiation and retention of tubers in four
cultivars: Estima, Maris Piper, Maris Peer
and Record. Ten of the experiments were carried out at Cambridge and two
near Valencia, Spain.
Other treatments included in some experiments were floating polythene mulch
and planting date.

Shading by up to 75% did not affect the timing of onset or cessation

of tuber initiation in Estima
but shading by 50% or more delayed the completion of tuber initiation
in Maris Piper compared with
less severe shading. Except for intensely shaded treatments (50% or more),

the majority of tubers
were initiated in a very short period (4–7 days). Shading by
37% or more during the period of tuber
initiation and increasing planting density, decreased number of
tubers per stem initiated in all
experiments, but number of tubers was not affected by shading at other
stages of growth. At
Cambridge, effects of shading on number of tubers >10 mm
retained later in growth from normal
planting dates (March to early May) were similar to effects on
number of tubers initiated, but effects
were much reduced or absent following later plantings at Cambridge and
in both experiments in
Valencia. The decreased effects of shading on number of tubers >10 mm
at late plantings at
Cambridge were associated with the initiation of fewer tubers
at these plantings. Effects of shading,
planting density and planting date on number of tubers were a consequence
of changes in the
frequency of occurrence and tuberization of different stolon
types. Increasing shading and planting
density and delaying planting reduced the number of lateral and
branch stolons and the frequency
of their tuberization but there were no effects on number of
primary stolons or their tuberization.
Consequently, at Cambridge a similar number of tubers was
borne on primary stolons in shaded and
unshaded crops. In Valencia a greater proportion of initiated
tubers was retained at final harvest from
shaded treatments than at Cambridge, which accounts for the absence of
effects of shading on
number of tubers >10 mm. The greater retention of tubers
late in growth in Spain may have been
associated with the higher peak growth rates achieved in higher
radiation fluxes than at Cambridge.

Linear regressions of the data for normal planting dates at
Cambridge and from Valencia indicated
that the number of tubers >10 mm late in growth was dependent on the
radiation environment
during the period of tuber initiation. Radiation flux during
the brightest period of the first few days
of initiation appeared to be the most crucial aspect of radiation
affecting number of tubers. As
incident radiation can vary greatly over the short period of tuber
initiation, it is potentially an
important factor affecting number of tubers in field crops.
Influence of headbugs (Eurystylus sp.) on sorghum
grain mould in the Nigerian savanna
Authors: MARLEY P. S. , MALGWI A. M.
Published: July 2002

The interaction between headbugs (Eurystylus sp.) and grain mould (GM) on sorghum was examined
in field trials carried out at Samaru, Nigeria in the 1995 and 1996 wet seasons. The results obtained
show that in all three sorghum cultivars tested, insect damage increased the number of fungal colonies
associated with the grain. This resulted in lower germination, 1000-grain mass and yield in such
treatments. Insect damage also altered the relative abundance of the common fungal flora species as,
following insect damage, Fusarium moniliforme (≡Gibberella fujikuroi), Phoma sorghina and
Curvularia lunata (≡Cochliobolus lunatus) were the most common fungi in decreasing order of
frequency as against the normal order of P. sorghina, F. moniliforme
followed by C. lunata. These
results are the first clear evidence of interactions between headbugs and GM in Nigeria.
Field experimentation on rough land: The method of
Papadakis reconsidered
Authors: PEARCE S. C.
Published: July 2002

Journal of Agricultural Science, Cambridge (1998), 131, 1

After the publication of this paper a fault was found in the software used to calculate the tables, the numbers
of rows and columns having at one point been interchanged. Although that will not affect results from the
square formats α and β, it could affect those from γ. Tables 2, 3 and 4 have been recalculated with the error
removed.
Effects of preflood nitrogen rate and midseason nitrogen timing on flooded rice
Authors: CARRERES R. , SENDRA J. , BALLESTEROS R. , GARCÍA DE LA CUADRA J.
Published: July 2002

A field study was conducted to investigate the agronomic performance, nitrogen (N) efficiencies, yield
components and yield of rice in Spain for different nitrogen treatments. The experimental variants
were six preflood N rates (0, 50, 75, 100, 125 and 150 kg/ha) and three topdressing patterns: (i) non-
topdressed, (ii) topdressed with 50 kg N/ha at mid-tillering stage (MT) and (iii) topdressed at panicle
initiation stage (PI). The N status of the plant was measured at different growing stages to determine
whether a chlorophyll meter would be useful in making N sidedress recommendations. The results
showed that grain yield increased with increasing amounts of preflooding N fertilizers up to
100 kg N/ha. The main effect was on panicle number per unit ground area. The effect of additional
N supply on yield components and grain yield depended on application timing. Split applications
of N did not improve the agronomic efficiency but reduced days to maturity and lodging and
increased the harvest index value. Split applications increased grain yield when the total N rate was
150 kg/ha with the second supply at PI. There was a significant but not very good relationship
between N content and chlorophyll content (SPAD) values. The regression equation differed
significantly depending on growth stage. The SPAD value may determine the need for N topdressing
at MT stage, but not at PI. However, the relationship between SPAD value and the rice yield increase
from N topdressing application was not very good.
Breeding oilseed rape for pod shattering resistance
Authors: MORGAN C. L. , LADBROOKE Z. L. , BRUCE D. M. , CHILD R. , ARTHUR A. E.
Published: July 2002

The genetic control of pod dehiscence was studied through the production, field trial and subsequent
analysis of a full diallel involving seven parents selected for high and low resistance to pod shattering.
Additive gene effects were most significant among the measures of pod shattering resistance with only
minor contributions from non-additive gene effects. Genetic variation in measures of the stiffness of
the pod wall were, however, determined by dominant gene effects. Genes for increased pod shattering
resistance acted recessively. All characters showed high levels of heritability. Correlations among pod
shatter resistance characters and other pod, raceme and plant characters were low suggesting that
resistance is likely to be independent of other important agronomic traits.
Treatment of acute Escherichia coli mastitis in cows with
enrofloxacin: effect on clinical signs and chemiluminescence of
circulating neutrophils
Authors: HOEBEN DAGMAR , MONFARDINI ERICA , BURVENICH CHRISTIAN , HAMANN JÖRN
Published: July 2002

We have studied the effect of treatment with enrofloxacin on local and
general clinical signs and chemiluminescence of circulating polymorphonuclear
leucocytes during experimentally induced Escherichia coli mastitis in cows immediately
after parturition. Twelve cows were infected with 104 cfu Esch. coli
P4[ratio ]O32 into both left quarters. Six cows received an intravenous injection of 5 mg
enrofloxacin/kg at 10 h after infection and a second enrofloxacin treatment
administered subcutaneously at 30 h post infection. The other six cows were controls
that received no treatment. General clinical signs (fever, tachycardia, loss of
appetite, reduced rumen motility and depression) were similar in both groups. Local
clinical signs, such as swelling, pain and firmness of the inflamed mammary quarters,
were less severe in the treated cows. We saw no difference in the appearance of the
milk[ratio ]flecks and watery or purulent milk were observed in both groups. The beneficial
effects of treatment with enrofloxacin were mainly on milk production and
composition. The decline in milk production and the changes in milk concentrations
of lactose, Na+ and bovine serum albumin were less pronounced in the treated cows.
Treatment with enrofloxacin accelerated the clearance of bacteria from the infected
quarters, but had no effect on the chemiluminescence response of isolated
polymorphonuclear leucocytes. The changes in the number of circulating leucocytes
and the appearance of immature neutrophils in the circulation of the treated cows
indicated possible beneficial effects on migration of neutrophils into the inflamed
glands. Higher milk somatic cell counts in the treated cows supported this
hypothesis. The results of this study indicated that treating cows that have been
experimentally infected with Esch. coli mastitis after parturition with enrofloxacin
reduced the severity of the disease, especially the decline in milk production and the
changes in milk composition.
An analytical model of gravity currents in a stable atmosphere
Authors: FELIKS YIZHAK
Published: July 2002

An analytical solution to the nonlinear equations of motion and thermodynamic
energy for gravity currents propagating in stable atmosphere is found. This solution
differs from the previous analytical studies in several aspects. In our solution the
head of the gravity current is a strong vortex and the dynamics are non-hydrostatic.
The solution has two regimes: (i) a supercritical regime when the Froude number
Fr = (c – U)/Na is larger than 1 – in this case the cold front is local; (ii) a subcritical regime when Fr is smaller than 1. Here, ahead of the front there is a disturbance of nonlinear gravity waves. The scale of the wave and its amplitude increase as the Froude number decreases.

We found that the square of the speed of the gravity current (relative to the
synoptic wind) is proportional to the mean drop of potential temperature over the
front area times the front height a. The constant of proportionality is function
of the environmental conditions. The thermal, velocity and vorticity fields can be described
by non-dimensional structure functions of two numbers: pa = 1/Fr
and ka. The amplitude of the structure functions is proportional
to (c – U) 2/a for the thermal field, to (c – U) for the velocity field, and to (c – U)/a for the vorticity field.

The propagation is studied in terms of the vorticity equation. The horizontal
gradient of the buoyancy term always tends to propagate the cold front. The nonlinear
advection term in most of the cases investigated here tends to slow the propagation
of the gravity current. The propagation of the disturbance of nonlinear gravity waves
ahead of the front in regime (ii) in most of the cases is due to the buoyancy term.
The nonlinear advection term tends to slow the propagation when the synoptic wind
blows in the direction opposite to that of the front propagation, and increase the
propagation when the synoptic wind blows in the direction of propagation.
On laminar separation at a corner point in transonic flow
Authors: RUBAN A. I. , TURKYILMAZ I.
Published: July 2002

The separation of the laminar boundary layer from a convex corner on a rigid body
contour in transonic flow is studied based on the asymptotic analysis of the Navier–Stokes
equations at large values of the Reynolds number. It is shown that the flow
in a small vicinity of the separation point is governed, as usual, by strong interaction
between the boundary layer and the inviscid part of the flow. Outside the interaction
region the Kármán–Guderley equation describing transonic inviscid flow admits a
self-similar solution with the pressure on the body surface being proportional to
the cubic root of the distance from the separation point. Analysis of the boundary
layer driven by this pressure shows that as the interaction region is approached the
boundary layer splits into two parts: the near-wall viscous sublayer and the main
body of the boundary layer where the flow is locally inviscid. It is interesting that
contrary to what happens in subsonic and supersonic flows, the displacement effect
of the boundary layer is primarily due to the inviscid part. The contribution of the
viscous sublayer proves to be negligible to the leading order. Consequently, the flow in
the interaction region is governed by the inviscid–inviscid interaction. To describe this
flow one needs to solve the Kármán–Guderley equation for the potential flow region
outside the boundary layer; the solution in the main part of the boundary layer was
found in an analytical form, thanks to which the interaction between the boundary
layer and external flow can be expressed via the corresponding boundary condition for
the Kármán–Guderley equation. Formulation of the interaction problem involves one
similarity parameter which in essence is the Kármán–Guderley parameter suitably
modified for the flow at hand. The solution of the interaction problem has been
constructed numerically.
Experimental and computational study of laminar cavity flows at hypersonic speeds
Authors: JACKSON A. P. , HILLIER R. , SOLTANI S.
Published: July 2002

This paper presents a combined experimental/computational study of a surface
cavity in a low Reynolds number Mach 9 flow. The geometry is based on a body
of revolution, which produces highly two-dimensional time-averaged flow for all
experimental test cases. A range of cavity length-to-depth ratios, up to a maximum
of 8, is investigated. These correspond to ‘closed’ cavity flows, with the free shear
layer bridging the entire cavity. For most cases the free shear layer is laminar.
However, there is evidence of three-dimensional unsteadiness which is believed to
be the consequence of Taylor–Görtler-type vortex formation. The effect of this is
first detected on the cavity floor but progressively spreads as the cavity length is
increased. For the longest cavities the flow is also influenced by the early stages of
laminar–turbulent transition in the free shear layer.
Robust feedback control of Rayleigh–Bénard convection
Authors: OR A. C. , CORTELEZZI L. , SPEYER J. L.
Published: July 2002

We investigate the application of linear-quadratic-Gaussian (LQG) feedback control,
or, in modern terms, [Hscr ]2 control, to the stabilization of the no-motion state against the
onset of Rayleigh–Bénard convection in an infinite layer of Boussinesq fluid. We use
two sensing and actuating methods: the planar sensor model (Tang & Bau 1993, 1994),
and the shadowgraph model (Howle 1997a). By extending the planar sensor model
to the multi-sensor case, it is shown that a LQG controller is capable of stabilizing
the no-motion state up to 14.5 times the critical Rayleigh number. We characterize
the robustness of the controller with respect to parameter uncertainties, unmodelled
dynamics. Results indicate that the LQG controller provides robust performances
even at high Rayleigh numbers.
A frictional Cosserat model for the slow shearing of granular materials
Authors: SRINIVASA MOHAN L. , KESAVA RAO K. , NOTT PRABHU R.
Published: July 2002

A rigid-plastic Cosserat model for slow frictional flow of granular materials, proposed
by us in an earlier paper, has been used to analyse plane and cylindrical Couette flow.
In this model, the hydrodynamic fields of a classical continuum are supplemented
by the couple stress and the intrinsic angular velocity fields. The balance of angular
momentum, which is satisfied implicitly in a classical continuum, must be enforced
in a Cosserat continuum. As a result, the stress tensor could be asymmetric, and
the angular velocity of a material point may differ from half the local vorticity. An
important consequence of treating the granular medium as a Cosserat continuum is
that it incorporates a material length scale in the model, which is absent in frictional
models based on a classical continuum. Further, the Cosserat model allows determination
of the velocity fields uniquely in viscometric flows, in contrast to classical
frictional models. Experiments on viscometric flows of dense, slowly deforming granular
materials indicate that shear is confined to a narrow region, usually a few grain
diameters thick, while the remaining material is largely undeformed. This feature
is captured by the present model, and the velocity profile predicted for cylindrical
Couette flow is in good agreement with reported data. When the walls of the Couette
cell are smoother than the granular material, the model predicts that the shear layer
thickness is independent of the Couette gap H when the latter is large compared to
the grain diameter dp. When the walls are of the same roughness as the granular
material, the model predicts that the shear layer thickness varies as
(H/dp)1/3 (in the
limit H/dp [Gt ] 1) for plane shear under gravity and cylindrical Couette flow.
Sound generation in a mixing layer
Authors: COLONIUS TIM , LELE SANJIVA K. , MOIN PARVIZ
Published: July 2002

The sound generated by vortex pairing in a two-dimensional

compressible mixing layer is investigated. Direct numerical

simulations (DNS) of the Navier–Stokes equations are used to

compute both the near-field region and a portion of the acoustic

field. The acoustic analogy due to Lilley (1974) is also solved with

acoustic sources determined from the near-field data of the DNS. It

is shown that several commonly made simplifications to the acoustic

sources can lead to erroneous predictions for the acoustic field.

Predictions based on the quadrupole form of the source terms derived

by Goldstein (1976a, 1984) are in excellent agreement with

the acoustic field from the DNS. However, despite the low Mach number

of the flow, the acoustic far field generated by the vortex pairings

cannot be described by considering compact quadrupole sources. The

acoustic sources have the form of modulated wave packets and the

acoustic far field is described by a superdirective model (Crighton

& Huerre 1990). The presence of flow–acoustic interactions

in the computed source terms causes the acoustic field predicted by

the acoustic analogy to be very sensitive to small changes in the

description of the source.
Inertial effect on the stability of viscoelastic

cone-and-plate flow
Authors: OLAGUNJU DAVID O.
Published: July 2002

The stability of axially symmetric cone-and-plate flow of an

Oldroyd-B fluid at

non-zero Reynolds number is analysed. We show that stability is controlled
by two

parameters: [Escr ]1≡DeWe and

[Escr ]2≡Re/We,

where De, We, and Re are the Deborah,

Weissenberg and Reynolds numbers respectively. The linear stability problem
is solved

by a perturbation method for [Escr ]2 small and by a Galerkin
method when

[Escr ]2=O(1).

Our results show that for all values of the retardation parameter β

and for all values of [Escr ]2

considered the base viscometric flow is stable if

[Escr ]1 is sufficiently small. As [Escr ]1

increases past a critical value the flow becomes unstable as a pair of

complex-conjugate eigenvalues crosses the imaginary axis into the right

half-plane. The critical value of [Escr ]1 decreases as

[Escr ]2 increases indicating that increasing inertia destabilizes
the

flow. For the range of values considered the critical wavenumber

kc first decreases

and then increases as [Escr ]2

increases. The wave speed on the other hand decreases

monotonically with [Escr ]2.

The critical mode at the onset of instability corresponds to

a travelling wave propagating inward towards the apex of the cone with
infinitely

many logarithmically spaced toroidal roll cells.
On the impulse response for swept boundary-layer flows
Authors: LINGWOOD R. J.
Published: July 2002

Swept-wedge flows are used to study the effects of pressure

gradient and flow angle on

the stability of three-dimensional laminar boundary layers. It is shown

that the flow is

absolutely unstable in the chordwise direction, i.e. disturbances grow

in time at every

chordwise location, for certain parameter combinations. However,

laminar–turbulent transition may still be a convective process.
Barotropic vortex pairs on a rotating sphere
Authors: DIBATTISTA MARK T. , POLVANI LORENZO M.
Published: July 2002

Using a barotropic model in spherical geometry, we construct new
solutions for
steadily travelling vortex pairs and study their stability properties.
We consider pairs
composed of both point and finite-area vortices, and we represent the rotating
background
with a set of zonal strips of uniform vorticity. After constructing the
solution
for a single point-vortex pair, we embed it in a rotating background, and
determine
the equilibrium configurations that travel at constant speed without changing
shape.
For equilibrium solutions, we find that the stability depends on the relative
strength
(which may be positive or negative) of the vortex pair to the rotating
background:
eastward-travelling pairs are always stable, while westward-travelling
pairs are unstable
when their speeds approach that of the linear Rossby–Haurwitz waves.
This
finding also applies (with minor differences) to the case when the vortices
are of finite
area; in that case we find that, in addition to the point-vortex-like instabilities,
the
rotating background excites some finite-area instabilities for vortex pairs
that would
otherwise be stable. As for practical applications to blocking events,
for which the
slow westward pairs are relevant, our results indicate that free barotropic
solutions
are highly unstable, and thus suggest that forcing mechanisms must play
an important
role in maintaining atmospheric blocking events.
The effects of wall inertia on flow in a two-dimensional collapsible
channel
Authors: LUO X. Y. , PEDLEY T. J.
Published: July 2002

The effect of wall inertia on the self-excited oscillations in

a collapsible channel flow
is investigated by solving the full coupled two-dimensional membrane–flow
equations.
This is the continuation of a previous study in which self-excited oscillations
were
predicted in an asymmetric channel with a tensioned massless elastic membrane
(Luo
& Pedley 1996). It is found that a different type of self-excited oscillation,
a form
of flutter, is superposed on the original large-amplitude, low-frequency
oscillations.
Unlike the tension-induced oscillations, the flutter has high frequency,
and grows with
time from a small amplitude until it dominates the original slower mode.
The critical
value of tension below which oscillations arise (at fixed Reynolds number)
is found to
increase as the wall inertia is increased. The rate at which energy is

(a) dissipated in the flow field and (b) transferred
to the
wall during the flutter is discussed, and results
at different parameter values are compared with those of a massless membrane.
There
is also a discussion of whether the onset of flutter, or that of the slower
oscillations,
is correlated with the appearance of flow limitation, as is thought to
be the case in
the context of wheezing during forced expiration of air from the lungs.
Minimal liquid bridges in non-axisymmetrically buckled elastic tubes
Authors: HEIL MATTHIAS
Published: July 2002

This study investigates the existence and stability of static liquid
bridges in non-axisymmetrically buckled elastic tubes. The liquid bridge which occludes
the tube is
formed by two menisci which meet the tube wall at a given contact angle
along a
contact line whose position is initially unknown. Geometrically nonlinear
shell theory
is used to describe the deformation of the linearly elastic tube wall in
response to
an external pressure and to the loads due to the surface tension of the
liquid bridge.
This highly nonlinear problem is solved numerically by finite element methods.

It is found that for a large range of parameters (surface tension, contact
angle
and external pressure), the compressive forces generated by the liquid
bridge are
strong enough to hold the tube in a buckled configuration. Typical meniscus
shapes
in strongly collapsed tubes are shown and the stability of these configurations
to
quasi-steady perturbations is examined. The minimum volume of fluid required
to
form an occluding liquid bridge in an elastic tube is found to be substantially

smaller than predicted by estimates based on previous axisymmetric models.
Finally,
the implications of the results for the physiological problem of airway
closure are
discussed.
Direct numerical simulations of turbulence with
confinement and rotation
Authors: GODEFERD F. S. , LOLLINI L.
Published: July 2002

The goal of this work is to analyse how solid body rotation affects forced turbulence
enclosed within solid boundaries, and to compare it to results of the experiment performed
by Hopfinger et al. (1982). In order to identify various mechanisms associated
with rotation, confinement, and forcing, a numerical pseudo-spectral code is used for
performing direct numerical simulations. The geometry is simplified with respect to
the experimental one. First, we are able to reproduce the linear regime, as propagating
inertial waves that undergo reflections at the walls. Second, the Ekman pumping phenomenon,
proportional to the rotation rate, is identified in freely decaying turbulence,
for which the evolution of the flow bounded by walls is compared to the evolution of
unbounded homogeneous turbulence. Finally we introduce a local forcing on a plane
in physical space, for simulating the effect of an oscillating grid, so that diffusive
turbulence is created, and we examine the structuring of the flow under the combination
of the linear and nonlinear mechanisms. A transition to an almost two-dimensional
state is shown to occur between the region close to the forcing and an outer region
in which vortices appear, the number of which depends on the Reynolds and Rossby
numbers. In this region, the anisotropy of turbulence is examined, and the numerical
predictions are shown to reproduce many of the most important features present in
the experimental flow.