bluuebunny/crossref_metadata_2025 huggingface dataset:
RELATIVE PALATABILITY AND SEASONAL AGRONOMIC PERFORMANCE OF SELECTED PASTURE LEGUMES FOR SPECIES MIXTURES IN DRY-SUBHUMID WEST AFRICA
Authors: PETERS M. , TARAWALI S. A. , SCHULTZE-KRAFT R.
Published: July 2002

Relative palatability and some agronomic traits were studied for nine legumes including Aeschynomene histrix, Centrosema brasilianum (two accessions), Centrosema pascuorum, Chamaecrista rotundifolia, Stylosanthes guianensis (two accessions) and Stylosanthes hamata (two accessions). All species were consumed by cattle but the relative palatability varied according to season. Only the two S. guianensis accessions were positively selected throughout the year. A positive relationship was established between the ability to retain green leaves in the dry season and palatability. Once established, the two C. brasilianum accessions out-performed the other legumes in their ability to stay green and retain leaves in the dry season; related to the ability to retain green leaves under drought conditions, C. brasilianum ILRI 155 was among the most palatable legumes in the dry season. S. guianensis accessions had the highest dry matter (DM) yields and one of them (ILRI 15557) had the highest nutritive value. In contrast with earlier results in the same environment, C. rotundifolia and A. histrix performed poorly in terms of DM productivity. The implications of the agronomic characteristics of the legumes for the management of legume-based pastures in crop/livestock systems are discussed and the concept of legume–legume mixtures, composed of several compatible species, is advocated.
INFLUENCE OF SOWING DATE ON THE GROWTH AND YIELD OF BAMBARA GROUNDNUT LANDRACES IN TANZANIA
Authors: COLLINSON S. T. , SIBUGA K. P. , TARIMO A. J. P. , AZAM-ALI S. N.
Published: July 2002

Sequential sowings were carried out at Dodoma, Tanzania, to examine the effect of changing climatic parameters on the growth and yield of bambara groundnut (Vigna subterranea). Sowings took place on 4 January, 4 February and 4 March 1994; 4 and 24 January, and 13 February 1995; 4 and 21 January, and 7 February 1996. Rainfall during the crop life cycle varied from 163 to 611 mm, mean photoperiod from 11.82 to 12.09 h d−1 and mean temperature from 22.6 to 24.4 °C. In 1994, the highest pod yields were achieved at the earliest sowing date, with a maximum of 2.87 and 1.42 t ha−1 for the red- and cream-seeded landraces, representing pod harvest indices of 0.56 and 0.34 respectively. A 30-d delay in sowing caused >60% reduction in pod yield, and a further 30-d delay resulted in no pods at all. Similarly, in 1995 successive delays in sowing caused dramatic yield declines, and the maximum yield was much lower, at 0.44 t ha−1. In 1996 there was no significant difference in pod yields between the two early sowing dates for the red-seeded landrace and yields were again lower than in 1994 with a maximum of 1.02 t ha−1. Differences in dry matter production between sowings and years were attributed mainly to differences in the amount and distribution of rainfall and to declining temperatures towards the end of the season; however, partitioning to pods was remarkably consistent across sowings.
EFFECTS OF STORAGE CONDITIONS AND PRESENCE OF FRUITING BRACTS ON THE GERMINATION OF ATRIPLEX HALIMUS AND SALSOLA VERMICULATA
Authors: OSMAN A. E. , GHASSALI F.
Published: July 2002

Two shrub species, Atriplex halimus L. and Salsola vermiculata L., are considered useful for rehabilitation of degraded rangelands in west Asia and north Africa. They can be established from direct seeding and are capable of self-sowing. In this study, seed storage at different temperatures and the influence of fruiting bracts on seed germination were examined for the two species during two seasons. Fruits (utricles) were stored at 20–22°C (room temperature), 0°C or −22°C. Germination tests were carried out after 33, 56, 90, 152, 272 and 397 d in storage in the first season and after 44, 76, 104, 170, 288 and 412 d in the second season. Seeds were germinated in their fruiting bracts or after bract removal. Bract removal significantly improved seed germination of both shrubs regardless of storage temperature. For S. vermiculata the increase in germination was in the range of 1.3- to 14.7-fold compared with values for the intact fruit in Season 1 and 0.5 to 3.8 in Season 2. Similarly the ranges for A. halimus were 0.5- to 4.2-fold and 0.7- to 5.3-fold in the two seasons respectively. The effect of cold storage was greater on Salsola than on Atriplex. The reduction of the storage temperature from 21°C to 0°C and −22°C increased the longevity of S. vermiculata seeds by 2.8–46.6 times in Season 1 and by 2.9–2.6 times in Season 2. There was little or no effect on the longevity of A. halimus. A leachate prepared by soaking fruiting bracts from S. vermiculata significantly depressed germination (p < 0.01), the effect being greater on Salsola seeds (20% reduction) than on Atriplex seeds (8% reduction). A leachate from A. halimus produced a slight but non-significant reduction in germination.
Maintenance of genetic variation in phenotypic plasticity: the role of environmental variation
Authors: de JONG GERDIEN , GAVRILETS SERGEY
Published: July 2002

We study genetic variation in phenotypic plasticity maintained by a balance between mutation and
weak stabilizing selection. We consider linear reaction norms allowing for spatial and/or temporal
variation in the environments of development and selection. We show that the overall genetic
variation maintained does not depend on whether the trait is plastic or not. The genetic variances
in height and slope of a linear reaction norm, and their covariance, are predicted to decrease with
the variation in the environment. Non-pleiotropic loci influencing either height or slope are
expected to decrease the genetic variance in slope relative to that in height. Decrease in the ratio of
genetic variance in slope to genetic variance in height with increasing variation in the environment
presents a test for the presence of loci that only influence the slope, and not the height. We use
data on Drosophila to test the theory. In seven of eight pair-wise comparisons genetic variation in
reaction norm is higher in a less variable environment than in a more variable environment, which
is in accord with the model's predictions.
The effect of synergistic epistasis on the inbreeding load
Authors: CHARLESWORTH BRIAN
Published: July 2002

The magnitude of inbreeding depression in Drosophila melanogaster

appears too large to be
accounted for by mutational load with multiplicative fitness interactions

among loci, if current
estimates of mutation and selection parameters are valid. One possible
explanation for this
discrepancy is synergistic epistasis among the fitness effects of
deleterious mutations. A simple
model of the effect of synergistic epistasis on the inbreeding load is

developed. This model is used
to show that deleterious mutations could account for the Drosophila

data on the effects of inbreeding on components of fitness such as viability.
Measure of non-compactness and interpolation methods associated to polygons
Authors: COBOS FERNANDO , FERNÁNDEZ-MARTÍNEZ PEDRO , MARTÍNEZ ANTÓN
Published: July 2002

We establish an estimate for the measure of non-compactness of an interpolated operator acting from a J-space into a K-space. Our result refers to general Banach N-tuples. We also derive estimates for entropy numbers if some of the N-tuples reduce to a single Banach space.
KAIS M. FIRRO, The Druzes in the Jewish State: A Brief History (Leiden, Boston, and Cologne: E. J. Brill, 1999). Pp. 274.
Authors: Timani Hussam S.
Published: July 2002

This well-researched book is a welcome contribution to the study of the Druzes, one of the most under-studied religious groups in the Middle East. The main objective of this book is to trace the historical development of the Druzes in Israel since the creation of the Jewish state in 1948 to the present, and to show that Druze ethnicity was and still is an instrument in the hands of the Israeli government officials and the Druze elite. This book also attempts to show how the Zionists used Druze ethnicity and ethnic issues to pursue their policy aims of alienating the Druzes from other Arabs. In this work, the author, a professor at the University of Haifa, revisits an area he knows well and has already presented in a previous book, A History of the Druzes.
SERGIO NOJA, ED., L'Arabie avant l'Islam (Aix-en-Provence: Édisud, 1994). Pp. 272.
Authors: Shahîd Irfan
Published: July 2002

Arabia is the cradle of Islam and the homeland of the Arabs, who spread that faith in a wide belt around the globe that extends from Central Asia to Western Europe. Because Islam's roots are in Arabia, that peninsula has claims on the attention of the historian of Islam both as a religion and as a world civilization—that of Medieval Islam. Although the history of Arabia before Islam is important, there is no doubt that the rise of Islam within the peninsula's confines imparted new significance to the history of the region. Because of its history in preIslamic times, the significance of the peninsula remains, relatively speaking, marginal, but has been relieved of that marginality by the fact that it became the birthplace of Islam.
SAHARAN CLIMATES Climats anciens du Nord de l'Afrique. By

ROBERT VERNET. Paris: L'Harmattan, 1995. Pp.

180. No price given (ISBN 2-7384-3332-4).
Authors: MCINTOSH RODERICK
Published: July 2002

During the last two decades, our knowledge of the Saharan

palaeoclimates has improved enormously. Several long-term regional

projects published their results, new methods of dating and of climate

or vegetation reconstruction came on line, and (especially) causal

models of global climatic mechanisms became much more sophisticated.

Until now, however, there has been no synthesis of these advances in

the vast Sahara. Robert Vernet has produced an admirable overview for

the specialist and for members of ancillary disciplines such as

history and archaeology. No comparable Saharan climate synthesis

exists anywhere in the anglophone literature.
Pan-African Chronology: A Comprehensive Reference to the

Black Quest for Freedom in Africa, the Americas, Europe and Asia, 1400–1865. By EVERETT

JENKINS, JR. North Carolina: McFarland, 1996. Pp.

viii + 440. £44.95 (ISBN 0- 7864-0139-7).
Authors: ADI HAKIM
Published: July 2002

Everett Jenkins' book is an admirable attempt to present

a comparative chronology of events in Africa and throughout the

African Diaspora. The volume is divided into five principal chapters,

corresponding to the five centuries covered, each preceded by a brief

introduction, and includes a short bibliography and guide to sources,

as well as an extensive and comprehensive index. In addition to

sections on Africa, Asia, Europe and the Americas, the author also

includes useful sections on ‘related historical

events’.
SETTLERS, THE STATE AND COLONIAL POWER: THE COLONIZATION OF QUEEN

ADELAIDE PROVINCE, 1834–37
Authors: LESTER ALAN
Published: July 2002

Queen Adelaide Province consisted of some 7,000 square miles of
Rarabe
Xhosa territory annexed by the British Cape colonial government in May

1835 during the Sixth Frontier War. The province was held only until the

end of 1836 when it was abandoned under pressure from the imperial
government, but it represented the first British attempt to extend direct

control over a large body of formerly independent Africans. No such
ambitious scheme had ever been attempted before in the Cape, and no such

scheme was to be attempted elsewhere in Africa until the late nineteenth

century.

Given its short-lived nature, Queen Adelaide Province has not been
extensively analysed in any of the prominent histories of the eastern Cape.

However, while the treatment is brief, its significance has been widely

recognized. This early, temporary colonization of Xhosa territory has served

as a lens through which to view colonial extension in the eastern Cape
as a
whole. In the late-nineteenth and early twentieth-century settler histories
of
George Cory and George McCall Theal, the annexation of Queen Adelaide
Province represents a temporary advance within a much broader colonial

progress. One episode in the epic attempt to extend colonial civilization

across ‘Kaffraria’, expansion within the province was unfortunately
thwarted
by misguided Cape and metropolitan philanthropy. In W. M. Macmillan's

liberal critique of the late 1920s and early 1930s, the disputes over the

province between the land-hungry settlers, the strategically-minded
Governor D'Urban and the humanitarian Secretary of State for the Colonies,

Lord Glenelg, are again viewed as part of a much broader struggle. But

rather than Cory's struggle between civilization and savagery, this
is seen as
a contest between malicious and benign conceptions of colonialism. The

province represents an early collision between, on the one hand, evangelical

and humanitarian versions of cultural colonization that guaranteed Xhosa

access to their land (a kind of trusteeship that Macmillan advocated for
his
own times) and, on the other hand, the practice of colonization founded
upon
settler-led conquest and dispossession.
EuroSOMNET – a European database of long-term experiments on soil organic matter: the WWW metadatabase
Authors: SMITH P. , FALLOON P. D. , KÖRSCHENS M. , SHEVTSOVA L. K. , FRANKO U. , ROMANENKOV V. , COLEMAN K. , RODIONOVA V. , SMITH J. U. , SCHRAMM G.
Published: July 2002

Since 1997, the EuroSOMNET project, funded by the EU-ENRICH programme, has assembled a metadatabase, and separate experimental databases, of European long-term experiments that investigate changes in soil organic matter. In this paper, we describe the WWW-based metadatabase, which is a product of this project. The database holds detailed records of 110 long-term soil organic matter experiments, giving a wide geographical coverage of Europe, and includes experiments from the European part of the former Soviet Union, many of which have not been available previously. For speed of access, records are stored as hyper-text mark-up language (HTML) files. In this paper, we describe the metadatabase, the experiments for which records are held, the information stored about each experiment, and summarize the main characteristics of these experiments. Details from the metadatabase have already been used to examine regional trends in soil organic matter in Germany and eastern Europe, to construct and calibrate a regional statistical model of humus balance in Russia, to examine the effects of climatic conditions on soil organic matter dynamics, to estimate the potential for carbon sequestration in agricultural soils in Europe, and to test and improve soil organic matter models. The EuroSOMNET metadatabase provides information applicable to a wide range of agricultural and environmental questions and can be accessed freely via the EuroSOMNET home page at URL: http://www.iacr.bbsrc.ac.uk/aen/eusomnet/index.htm.
Urea as a nitrogen fertilizer for cereals
Authors: LLOYD A. , WEBB J. , ARCHER J. R. , SYLVESTER-BRADLEY R
Published: July 2002

Twenty-six experiments were carried out in England and Wales from 1983 to 1985 to compare urea and ammonium nitrate (AN) as N top-dressing for cereals over the range 100–300 kg/ha N. Most of the experiments were sited on chalky or other soils of pH>7·0 where the greatest differences in effectiveness were expected.

The results showed that while relative N offtake in grain was 2·5% greater from AN, there was no difference in grain yield. Splitting the main N application increased N offtake from urea but not from AN. Overall, urea effectiveness from a single application at GS 31 increased with increasing rainfall on the day of application, but was not increased by subsequent rainfall. On chalk soils, urea effectiveness increased with increasing cumulative rainfall up to the fifth day after application. There was little effect of rainfall on urea effectiveness when the dressing was split. Although grain yield was unaffected by the type of fertilizer N applied, grain N concentration was usually less from urea.

The fertilizer N requirement for optimum yield (Nopt) wassimilar for both fertilizers. Splitting the main N application had no effect on yield or Nopt. We concludethat urea is a satisfactory source of N for cereals.
Effect of temperature and carpel size during
pre-anthesis on potential grain weight in wheat
Authors: CALDERINI D. F. , ABELEDO L. G. , SAVIN R. , SLAFER G. A.
Published: July 2002

The effect of environmental conditions immediately before anthesis on potential grain weight was
investigated in wheat at the experimental field of the Faculty of Agronomy (University of Buenos
Aires, Argentina) during 1995 and 1996. Plants of two cultivars of wheat were grown in two
environments (two contrasting sowing dates) to provide different background temperature conditions.
In these environments, transparent boxes were installed covering the spikes in order to increase spike
temperature for a short period (c. 6 days) immediately before anthesis, i.e. between ear emergence and
anthesis. In both environments, transparent boxes increased mean temperatures by at least 3·8 °C.
These increases were almost entirely due to the changes in maximum temperatures because minimum
temperatures were little affected. Final grain weight was significantly reduced by higher temperature
during the ear emergence–anthesis period. It is possible that this reduction could be mediated by the
effect of the heat treatment on carpel weight at anthesis because a curvilinear association between
final grain weight and carpel weight at anthesis was found. This curvilinear association may also
indicate a threshold carpel weight for maximizing grain weight.
Effects of planting date and dinocap applications on
the control of powdery mildew and yields of seed and
seed oil in coriander
Authors: KALRA A. , PARAMESWARAN T. N. , RAVINDRA N. S. , GOPAL RAO M. , KUMAR SUSHIL
Published: July 2002

Experiments were conducted during 1992/93 and 1993/94 to determine the effect of different planting
dates and dinocap applications on control of powdery mildew and yields of early and late maturing
coriander cultivars. Early plantings resulted in lower overall disease severity values for both the
cultivars, but the late maturing cultivar S-33 benefited more than RD-44, an early maturing cultivar.
Early planting resulted in smaller increases in yield in RD-44 but provided considerable economic
gains in S-33. Further, it was possible to achieve similar levels of control of powdery mildew and
yields in coriander with fewer dinocap applications by early plantings of both the cultivars. Therefore,
to reduce the fungicide inputs, it is important that emphasis should be placed on early plantings for
managing powdery mildew especially in environments conducive for its development.
Long-term yield patterns in barley-based cropping systems in Northern Syria. 3. Barley monocropping
Authors: JONES M. J. , SINGH M.
Published: July 2002

Results from monocropped barley treatments in long-term rotation (RTN) and continuous barley
(CB) trials at two sites were examined for fertilizer effects on yield means and long-term yield trends.
In RTN trials, mean responses to fertilizer (N[ratio ]P2O5) applied annually at rates of 20[ratio ]60 at the drier
and 40[ratio ]60 at the wetter site were almost double those from biennial application, confirming the need
for annual fertilization in monocropped barley systems. In CB trials, with N and P applied annually
in nine factorial combinations, at rates up to 120[ratio ]90, responses to each nutrient were curvilinear and
dependent on the presence of the other nutrient. Trend analysis showed a decline in grain yields over
time where NP fertilizer had not been applied or applied only at low annual rates (< 60[ratio ]45 or
< 60[ratio ]90, according to site); but straw yields, at worst, remained approximately stable in the absence
of fertilizer and generally increased strongly with higher NP rates. Uncertainties in the interpretation
of trend-analysis results indicate the need for methodology improvements, to include (i) additional
single-value parameters of the growth environment, to improve the model's ability to account for
seasonal variability, and (ii) a more flexible, non-linear function for time.

It was concluded that barley monocropping is not necessarily non-sustainable in the medium term,
provided adequate annual fertilization is maintained; but risks of pest or disease build-up, in addition
to the superiority of legume-barley systems in biomass and crude protein output demonstrated in
preceding papers, undoubtedly favour the introduction of some forage legumes into long-term barley
sequences. The most practicable (and acceptable) systems may well be ones in which continuous
barley is interrupted by a legume, or even a bare fallow, every third or fourth year. Above all, farmers
should be helped to experiment with different forage legumes, barley–legume sequences, and modes
of legume harvest, to optimize outputs in relation to their evolving and individual enterprise needs.
NATURE, NURTURE AND FIRST SEXUAL INTERCOURSE IN THE USA: FITTING BEHAVIOURAL GENETIC MODELS TO NLSY KINSHIP DATA
Authors: RODGERS JOSEPH LEE , ROWE DAVID C. , BUSTER MAURY
Published: July 2002

Fisher (1930) presented both theoretical and empirical results concerning genetic influences on fertility. Since then, only sparse research has been done on the genetics of fertility, although more sophisticated methodogy and data now exist than were available to Fisher. This paper presents a behavioural genetic analysis of age at first intercourse, accounting for genetic, shared environmental, and selected non-shared environmental influences. The data came from the nationally representative National Longitudinal Survey of Youth (NLSY). A newly developed kinship linking procedure was used that identifies links for cousins, half-siblings, full-siblings and twins in the NLSY. The results suggest a genetic influence in the overall dataset, and also among whites and in male–male and opposite-sex pairs. Genetic influences were extremely small or non-existent for blacks and for female–female pairs. Shared environmental influences were small for most subsets of the data, but moderate for female–female pairs. Two specific non-shared environmental influences – self-esteem and locus of control – were ruled out as accounting for any meaningful variance, although other general sources of non-shared environmental influence appear potentially important. Analysis of selected samples from upper and lower tails suggested that genetic influences are important in accounting for both early and late non-virginity. These findings are consistent with work reported by Miller et al. (1999), who used molecular genetic methods. Generally, these findings support the existence of genetic influences and implicate non-shared environmental influences as being important determinants of the timing of loss of virginity among US adolescents and young adults.
Proteolysis and formation of volatile compounds in cheese manufactured with a bacteriocin-producing adjunct culture
Authors: OUMER ABDELGHANI , GAYA PILAR , FERNÁNDEZ-GARCÍA ESTRELLA , MARIACA RAÚL , GARDE SONIA , MEDINA MARGARITA , NUÑEZ MANUEL
Published: July 2002

Hispánico cheese, a semi-hard Spanish variety, was manufactured from a
mixture of pasteurized cows' and ewes' milks (4[ratio ]1) using a commercial mesophilic
LD-type starter comprising Lactococcus lactis subsp. cremoris, Lc. lactis subsp. lactis,
Lc. lactis subsp. lactis var diacetylactis and Leuconostoc mesenteroides subsp. cremoris.
Varying amounts (0–1·0 g/kg) of an Enterococcus faecalis INIA 4 culture in milk were
added as a bacteriocin-producing adjunct. Differences in pH between cheeses
manufactured with and without the bacteriocin producer did not exceed 0·11 pH
units. Starter lactococci lost viability more rapidly in cheeses made with the
bacteriocin producer, which reached counts of up to 6×107 cfu/g during ripening.
Aminopeptidase activity in 1-d-old cheese made from milk inoculated with 1·0 g
bacteriocin-producing culture/kg was twice that in control cheese. Degrees of overall
proteolysis and levels of total free amino acids in 45-d-old cheese made with 1·0 g
bacteriocin-producing culture/kg were 1·80-fold and 2·17-fold those in control cheese
of the same age. Inoculating milk with 1·0 g/kg bacteriocin-producing culture
reduced the level of hydrophobic peptides in the resultant cheese, increased the
concentrations of 3-methyl-1-butanal, diacetyl and acetoin, and resulted in the
highest scores for flavour quality and flavour intensity throughout ripening.
Decreased number and bactericidal activity against Staphylococcus aureus of the resident cells in milk of dairy cows during early lactation
Authors: DOSOGNE HILDE , VANGROENWEGHE FRÉDÉRIC , BARRIO BELEN , RAINARD PASCAL , BURVENICH CHRISTIAN
Published: July 2002

Phagocytic and bactericidal activity of polymorphonuclear neutrophil leukocytes (PMN) isolated from blood and milk, against Staphylococcus aureus, was compared between groups of six healthy dairy cows in early, mid- and late lactation using a bacteriological assay. PMN were isolated from blood with a high degree of purity, but the cells isolated from milk contained variable amounts of macrophages (MΦ) and lymphocytes (L). The results were therefore calculated using the percentage PMN in order to evaluate phagocytosis and killing by PMN only. Blood PMN phagocytosed 82% Staph. aureus and milk PMN 43% on average and there was no significant difference between the different stages of lactation. The bactericidal activity of blood PMN against Staph. aureus was 36±8% in early lactation (significantly different from mid lactation, P<0·05), 64±10% in mid lactation and 53±6% in late lactation. Milk PMN killed only 6±3% Staph. aureus in early lactation (significantly different from mid lactation, P<0·01), 27±3% in mid lactation and 20±9% Staph. aureus in late lactation. The ratio of the bactericidal activity of milk to blood PMN was 0·08, 0·43 and 0·22 in early, mid- and late lactation, respectively. In addition to the decreased function, the number of cells in milk (somatic cell count, SCC) was also 60% lower in early lactation than in mid lactation cows (P<0·01). Our results suggest an impairment of blood and milk-resident PMN bactericidal activity against Staph. aureus and a decreased number of milk-resident PMN in dairy cows at the onset of lactation.
Purification and immunochemical quantitation of Penicillium
roqueforti acid aspartyl proteinase
Authors: BRACQ EMMANUELLE , LEVIEUX ANNIE , LEVIEUX DIDIER
Published: July 2002

Acid aspartyl proteinase of Penicillium roqueforti
was purified from
culture filtrates using FPLC ion-exchange chromatography on Mono Q and
size
exclusion chromatography on Superdex 75. The purity obtained allowed us
to
produce, using rabbits, a specific antiserum which was then used to develop
a
sandwich ELISA. The test was sensitive (detection limit,
0·25 ng/ml), reproducible
(CV, 3·1–6·9%) and closely correlated with
enzyme activity measurement (r=0·995,
P<0·001). This ELISA should be a valuable tool
for monitoring acid aspartyl
proteinase level in culture filtrates and for determining the
enzyme activity[ratio ]enzyme
protein ratio of acid aspartyl proteinase obtained after genetic recombinations
or
site-directed mutagenesis.
Variation of water-holding capacity and mechanical properties
between the particle size fractions of mineral acid, lactic and rennet

casein curds
Authors: TEO CHENG TET , MUNRO PETER A. , SINGH HARJINDER
Published: July 2002

Mineral acid casein, lactic casein and rennet casein curds were
prepared
either in the laboratory or on pilot-scale equipment. The water-holding
capacities of
mineral acid casein curd particles prepared in the laboratory
were relatively constant
for particle sizes >4 mm both after sieving and after
centrifugation; however, they
increased dramatically at smaller particle sizes to a maximum of
7·2 g water/g dry
curd after sieving and 4·3 g water/g dry curd after
centrifugation at 4060 g for the
size fraction that passed a 0·85 mm screen. The mechanical strength
of the
centrifugally compressed curd as assessed by a penetrometer probe also
decreased
dramatically with decrease in particle size. This variation of mineral

acid casein curd
properties with particle size was attributed partly to variation in particle

pH at the
instant of curd formation because of imperfect mixing of acid and skim
milk, i.e.
localized pH gradients. Lactic casein and rennet casein curds and curd
formed by
acidification of skim milk with glucono-δ-lactone also produced
similar but smaller
variations in curd properties with particle size. These curd particles
are
all formed by
break up of a quiescent gel and the variation in curd properties with
particle size was
attributed to variations in mechanical strength in the original milk gel,
i.e. weak
areas of the gel break up more easily, resulting in small, weak curd particles.
Autolysis of Lactobacillus helveticus and Propionibacterium
freudenreichii in Swiss cheeses: first evidence by using species-specific
lysis markers
Authors: VALENCE FLORENCE , RICHOUX ROMAIN , THIERRY ANNE , PALVA AIRI , LORTAL SYLVIE
Published: July 2002

Lactobacillus helveticus and Propionibacterium
freudenreichii are essential
starters in Swiss cheesemaking and the release of their intracellular enzymes
through
autolysis could significantly influence ripening. To provide evidence of
this lysis,
cheese made from microfiltered thermized milk inoculated with Lb. helveticus
ITGLH77, Prop. freudenreichii ITGP23 and
a commercial Streptococcus thermophilus
was assayed. Starter viability was determined and lysis was monitored during
ripening by protein analysis with SDS-PAGE of aqueous cheese extracts and
by
immunoblot detection of intracellular proteins: dipeptidase (PepD) for
Lb. helveticus
and methylmalonyl coenzyme A mutase for Prop. freudenreichii.
We verified that the
species specificity of these lysis markers was towards the cytoplasms of
all the species
currently used in Swiss cheese. Lb. helveticus exhibited an almost
complete loss of
viability (99·9%) from the beginning of ripening in the cold room;
concomitantly
PepD appeared in the cheese extracts and was detected until the end of
ripening.
Damaged Lb. helveticus cells were also visualized by scanning
electron microscopy. In
addition, free PepD was also successfully detected in commercial Swiss-related
cheeses. All these results clearly demonstrated the autolysis of
Lb. helveticus in Swiss
cheese. Prop. freudenreichii ITGP23 grew during warm room ripening
and no loss of
viability was detected after maximal growth (109 cfu/g
cheese). Free methylmalonyl-coenzyme A mutase was detected
at the end of ripening during cold storage, when
the cheese extracts were concentrated 20-fold, demonstrating that the autolysis
of
Prop. freudenreichii was tardy and limited.
Atosiban, an oxytocin receptor blocking agent: pharmacokinetics
and inhibition of milk ejection in dairy cows
Authors: WELLNITZ OLGA , BRUCKMAIER RUPERT M. , ALBRECHT CHRISTIANE , BLUM JÜRG W.
Published: July 2002

Plasma concentrations of the oxytocin receptor blocking agent Atosiban
were measured at 2, 4, 10, 15 and 20 min after injection of 5, 10, 20 and
50 μg
Atosiban/kg body weight in six dairy cows. The half life of Atosiban
was 18 min and
the total body clearance was 3301 ml/min. Intramammary pressure (IMP)
within
the teat cistern was measured in six cows before and after i.v. injection
of 0 or 20 μg
Atosiban/kg body weight and repeated injections of 0·2 or 0·5
i.u. oxytocin. IMP was
also measured in eleven cows after injection of 0, 10 or 50 μg Atosiban/kg
body
weight: in seven during oxytocin infusions, in four after oxytocin injections
in
successively increasing dosages (0·05, 0·1, 0·2, 0·5,
1 and 10 i.u.). The occurrence of
milk ejection was indicated by a rise in IMP. After injection of 20 μg
Atosiban/kg
body weight, 0·2 i.u. oxytocin did not induce an IMP rise before
48 min, whereas 0·5
i.u. oxytocin induced an IMP rise within 4 min. The time from the start
of infusion
until the beginning of the IMP rise and the duration of IMP rise during
oxytocin
infusions both increased, whereas the IMP rise itself was diminished by
increasing
Atosiban dosages. The amount of injected oxytocin necessary to induce an
IMP
response increased with increasing Atosiban dosages. Atosiban was shown
to have a
powerful effect in inhibiting milk ejection in dairy cows.
Laminar–turbulent transition in Poiseuille pipe flow subjected to periodic perturbation emanating from the wall.
Part 2. Late stage of transition
Authors: HAN G. , TUMIN A. , WYGNANSKI I.
Published: July 2002

Transition in a fully developed circular pipe flow was investigated experimentally
by introducing periodic perturbations. The simultaneous excitation of helical modes
having indices m = ±1, ±2 and ±3 was chosen. The experiments revealed that the
late stage of transition is accompanied by the formation of streaky structures that
are associated with peaks and valleys in the azimuthal distribution of the streamwise
velocity disturbance. The breakdown to turbulence starts with the appearance of
spikes in the temporal traces of the velocity. Spectral characteristics of these spikes
and the direction of their propagation relative to the wall are similar to those in
boundary layers. Analysis of the data suggests the existence of a high-shear layer in
the instantaneous velocity profile.

Additional experiments in which a very weak, steady flow was added locally to the
periodic axisymmetric perturbation were also carried out. These experiments resulted
in the generation of a single peak in the azimuthal distribution of the disturbance
amplitude. The characteristics of the transition process (spikes, vortical patterns etc.)
within this peak were similar to ones observed in the helical excitation experiments.
Based on these results one may conclude that late stages of transition in a pipe
flow and in a boundary layer are similar. The present report is part of an ongoing
investigation that was initiated by Eliahou, Tumin & Wygnanski (1998a).
Effect on a laminar boundary layer of small-amplitude streamwise vorticity in the upstream flow
Authors: WUNDROW DAVID W. , GOLDSTEIN M. E.
Published: July 2002

This paper is a generalization of a previous analysis of the effects of a small-amplitude,
steady, streamwise vorticity field on the flow over an infinitely thin flat plate in an
otherwise uniform stream. That analysis, which is given in Goldstein & Leib (1993),
required that the disturbance Reynolds number (i.e. the Reynolds number based
on the disturbance velocity and length scale) be infinite while the present paper
considers the more general case where this quantity can be finite. The results show
how an initially linear perturbation of the upstream flow ultimately leads to a small-amplitude but nonlinear cross-flow far downstream from the leading edge. This
flow can, under certain conditions, cause the streamwise velocity profiles to develop
distinct shear layers in certain localized spanwise regions. These shear layers, which are
remarkably similar to the ones that develop in Tollmien–Schlichting-wave transition
(Kovasznay, Komoda & Vasudeva 1962), are highly inflectional and can therefore
support the rapidly growing inviscid instabilities that are believed to break down
into turbulent spots (Greenspan & Benney 1963, and, subsequently, many others).
Numerical computations are carried out for input parameters which approximate the
flow conditions of some recent experimental studies of the so-called Klebanoff-mode
phenomenon. The results are used to explain some of the experimental observations,
and, more importantly, to explain why the averaged quantities usually reported
in these experiments do not correlate well with the turbulent-spot formation and
therefore with the overall transition process.
Acoustics of a two-dimensional compact jet impinging normally onto a flat plate
Authors: KUO CHIH-YU , DOWLING ANN P.
Published: July 2002

Vortex sound is revisited for two-dimensional compact jets. The interactions between
the flow and the rigid boundaries of the nozzle are included. Jets with steady upstream
conditions and with imposed forcing are considered. A multipole expansion for the
acoustic radiation is derived by the method of matched asymptotic expansion. The
processes are carried out to higher order to obtain the quadrupole impingement sound
in addition to the leading monopole. The emitted sound is found to be related to
the vortical flow motion and the scattering of the incoming forcing from the nozzle
interior. The flow motion is simulated incompressibly using a point vortex model.
The discretization of the continuous vortex shedding is carefully treated to fulfil the
Kutta condition and to eliminate spurious sound radiation. Numerical calculations
are given for both free and forced jets. For small forcing, the leading monopole is
weak and, under some circumstances, the quadrupole sound can be dominant.
Gravity waves on shear flows
Authors: MILES JOHN
Published: July 2002

The eigenvalue problem for gravity waves on a shear flow of depth h and non-inflected
velocity profile U(y) (typically parabolic) is revisited, following Burns (1953)
and Yih (1972). Complementary variational formulations that provide upper and
lower bounds to the Froude number F as a function of the wave speed c and
wavenumber k are constructed. These formulations are used to improve Burns's long-wave
approximation and to determine Yih's critical wavenumber k∗, for which the
wave is stationary (c = 0) and to which k must be inferior for the existence of an
upstream running wave.
Dynamics of monopolar vortices on a topographic beta-plane
Authors: FLÓR J.-B. , EAMES I.
Published: July 2002

The dynamics of a cyclonic monopolar vortex on a topographic beta-plane are studied
experimentally and theoretically. Detailed measurements of the vortex structure
are conducted using high-resolution quantitative velocity measurements. The initial
velocity profiles were described in terms of a radius Rvm, maximum azimuthal velocity
vθm, and a dimensionless parameter α which characterizes the steepness of the
velocity profile. The initial direction of motion of the monopolar vortex is critically dependent
on α and weakly dependent of the initial strength and size of the vortex: isolated vortices
(α ∼ 3) move north, whereas non-isolated vortices characterized by α ∼ 1 move
northwest. When the azimuthal velocity decays slowly with radial distance (α < 1.4),
Rossby wave generation dominates the vortex dynamics and the translational speed
of the vortex correlates with the Rossby wave speed. When the azimuthal velocity
decays rapidly with radial distance (α > 1.4) the vortex is isolated and the translational
speed is much slower than the Rossby wave speed. To interpret the effect of the
vortex structure on the direction of motion, a mechanistic model is developed which
includes the Rossby force and a lift force arising from circulation around the vortex,
but does not include the effect of Rossby waves. The Rossby force results from the
integrated effect of the Coriolis force on the vortex and drives the vortex north; the
lift force is determined from the circulation around the vortex and drives the vortex
west. Comparison with the experimental data reveals two regimes: α < 1.4, where the
vortex dynamics are dominated by Rossby waves whereas for α > 1.4 Rossby waves
are weak and favourable agreement is found with the mechanistic model.
On the nonlinear Helmholtz response of

almost-enclosed tidal basins with sloping bottoms
Authors: MAAS LEO R. M.
Published: July 2002

Short relatively deep tidal basins, which are connected to the
open

sea by a narrow

strait, may exhibit either an amplified (resonant), or damped (choked)
response to

the tide at the entrance. Here particular attention is given to the lowest
mode of

response, which is the Helmholtz or pumping mode, for which the sea level
within

the basin executes a spatially uniform oscillation. When the

basin's sidewalls slope,

the restoring process of this oscillator is nonlinear. Possible consequences
of this

nonlinearity are that the basin may exhibit either long-lasting

high-waters and short,

peaked low-waters or long-term regular modulation of its tidal amplitude,

or a chaotic

modulation of its tidal amplitude, or ‘bent resonance horns’,

implying that resonant

and choked tidal responses may exist simultaneously for the same parameter
regime.

Related field observations will be discussed.
Passive scalar statistics in high-Péclet-number grid turbulence
Authors: MYDLARSKI L. , WARHAFT Z.
Published: July 2002

The statistics of a turbulent passive scalar (temperature) and
their Reynolds
number dependence are studied in decaying grid turbulence for the Taylor-microscale

Reynolds number, Rλ, varying from 30 to 731

(21[les ]Peλ[les ]512). A principal objective

is, using a single (and simple) flow, to bridge the gap between the existing
passive
grid-generated low-Péclet-number laboratory experiments and those
done
at high Péclet number in the atmosphere and oceans. The turbulence

is generated by means of an active grid and the passive temperature
fluctuations are generated by a mean transverse
temperature gradient, formed at the entrance to the wind tunnel plenum
chamber by
an array of differentially heated elements. A well-defined inertial–convective
scaling
range for the scalar with a slope, nθ,
close to the Obukhov–Corrsin value of 5/3, is
observed for all Reynolds numbers. This is in sharp contrast with the velocity
field,
in which a 5/3 slope is only approached at high
Rλ. The Obukhov–Corrsin constant,
Cθ, is estimated to be 0.45–0.55.
Unlike the velocity spectrum, a bump occurs in the
spectrum of the scalar at the dissipation scales, with increasing prominence
as the
Reynolds number is increased. A scaling range for the heat flux cospectrum
was also
observed, but with a slope around 2, less than the 7/3 expected from
scaling theory.
Transverse structure functions of temperature exist at the third and fifth
orders, and,
as for even-order structure functions, the width of their inertial subranges
dilates
with Reynolds number in a systematic way. As previously shown for shear
flows,
the existence of these odd-order structure functions is a violation of
local isotropy
for the scalar differences, as is the existence of non-zero values of the
transverse
temperature derivative skewness (of order unity) and hyperskewness (of
order 100).
The ratio of the temperature derivative standard deviation along and normal
to the
gradient is 1.2±0.1, and is independent of Reynolds number. The
refined similarity
hypothesis for the passive scalar was found to hold for all
Rλ, which was not the case
for the velocity field. The intermittency exponent for the scalar,
μθ, was found to be
0.25±0.05 with a possible weak Rλ
dependence, unlike the velocity field, where μ was
a strong function of Reynolds number. New, higher-Reynolds-number results
for the
velocity field, which smoothly follow the trends of Mydlarski & Warhaft
(1996), are
also presented.
Weakly nonlinear shear waves
Authors: FEDDERSEN FALK
Published: July 2002

Alongshore propagating low-frequency O(0.01 Hz)
waves related to the direction and
intensity of the alongshore current were first observed in the surf zone
by Oltman-Shay,
Howd & Birkemeier (1989). Based on a linear stability analysis, Bowen
&
Holman (1989) demonstrated that a shear instability of the alongshore current
gives
rise to alongshore propagating shear (vorticity) waves. The fully nonlinear
dynamics of
finite-amplitude shear waves, investigated numerically by Allen, Newberger
& Holman
(1996), depend on α, the non-dimensional ratio of frictional to nonlinear
terms,
essentially an inverse Reynolds number. A wide range of shear wave environments

are reported as a function of α, from equilibrated waves
at larger α to fully turbulent
flow at smaller α. When α is above the critical level
αc, the system is stable. In this
paper, a weakly nonlinear theory, applicable to α just
below αc, is developed. The
amplitude of the instability is governed by a complex Ginzburg–Landau
equation. For
the same beach slope and base-state alongshore current used in Allen et
al. (1996),
an equilibrated shear wave is found analytically. The finite-amplitude
behaviour of
the analytic shear wave, including a forced second-harmonic correction
to the mean
alongshore current, and amplitude dispersion, agree well with the numerical
results of
Allen et al. (1996). Limitations in their numerical model prevent
the development of
a side-band instability. The stability of the equilibrated shear wave is
demonstrated
analytically. The analytical results confirm that the Allen
et al. (1996) model correctly
reproduces many important features of weakly nonlinear shear waves.
Capillary flow in an interior corner
Authors: WEISLOGEL MARK M. , LICHTER SETH
Published: July 2002

The design of fluids management processes in the low-gravity environment
of space
requires an accurate description of capillarity-controlled flow in containers.
Here we
consider the spontaneous redistribution of fluid along an interior corner
of a container
due to capillary forces. The analytical portion of the work presents an
asymptotic
formulation in the limit of a slender fluid column, slight surface curvature
along the flow
direction z, small inertia, and low gravity. The scaling introduced
explicitly accounts
for much of the variation of flow resistance due to geometry and so the
effects of
corner geometry can be distinguished from those of surface curvature. For
the special
cases of a constant height boundary condition and a constant flow condition,
the
similarity solutions yield that the length of the fluid column increases
as
t1/2 and t3/5,
respectively. In the experimental portion of the work, measurements from
a 2.2 s drop
tower are reported. An extensive data set, collected over a previously
unexplored range
of flow parameters, includes estimates of repeatability and accuracy, the
role of inertia
and column slenderness, and the effects of corner angle, container geometry,
and fluid
properties. At short times, the fluid is governed by inertia
(t[lsim ]tLc).
Afterwards, an
intermediate regime
(tLc[lsim ]t[lsim ]
tH) can be shown to be modelled by a constant-flow-like
similarity
solution. For t[ges ]tH it is found

that there exists a location zH at which
the interface height remains constant at a value
h(zH, t)=H which
can be shown
to be well predicted. Comprehensive comparison is made between the analysis
and
measurements using the constant height boundary condition. As time increases,
it is
found that the constant height similarity solution describes the flow over
a lengthening
interval which extends from the origin to the invariant tip solution. For

t[Gt ]tH, the
constant height solution describes the entire flow domain. A formulation
applicable
throughout the container (not just in corners) is presented in the limit
of long times.
Transition from dripping to jetting
Authors: CLANET CHRISTOPHE , LASHERAS JUAN C.
Published: July 2002

We consider the critical Weber number
(Wec≡
ρV20D/σ)
at which the transition from
dripping to jetting occurs when a Newtonian liquid of density ρ and
surface tension
σ is injected with a velocity V0 through a tube

of diameter D downward into stagnant
air, under gravity g. We extend Taylor's (1959) model for

the recession speed of a free
edge, and obtain in the inviscid limit an exact solution which includes
gravity and
inertia effects. This solution provides a criterion for the transition
which is shown to
occur at a critical Weber number

formula here

where Bo and Boo are the Bond numbers
(Bo≡[ρgD2/(2σ)]1/2),

respectively based on the inside and outside diameter of the tube, and
K is a
constant equal to 0.37 for the case of water injected in air. This critical
Weber
number is shown to be in good agreement with existing experimental values
as well as
with new measurements performed over a wide range of Bond numbers.