bluuebunny/crossref_metadata_2025 huggingface dataset:
Responses in plasma free fatty acid composition

to divergent selection for predicted carcass lean content in sheep
Authors: SPEAKE B. K. , NOBLE R. C. , BRACKEN J. , BISHOP S. C.
Published: July 2002

The fatty acid composition of the plasma free fatty acid and adipose

tissue triacylglycerol fractions

was determined in lean and fat selection lines of Texel-Oxford and Scottish

Blackface sheep at the 6th

year of divergent selection. The mean proportion of 18[ratio ]2n-6 in the

triacylglycerol of subcutaneous

backfat was 1·3-fold higher in the phenotypically fatter

sheep in the fat lines than in the

phenotypically leaner sheep in the lean lines. Regression analysis

indicated a positive relationship

between this fatty acid and backfat depth whereas the proportion of

18[ratio ]1n-9 in the tissue

triacylglycerol was negatively related to fatness. The proportions of

18[ratio ]2n-6 and of other

polyunsaturated fatty acids in the plasma free fatty acid fraction were

much higher than in adipose

triacylglycerol. For the Scottish Blackface sheep in the fed state, the

mean proportion of 18[ratio ]2n-6 in

plasma free fatty acid (measured on all sheep) was 1·4-fold greater

in the fat line than in the lean line.

Regression analysis indicated a positive relationship between the plasma

content of this fatty acid and

backfat thickness whereas the proportion of 18[ratio ]1n-9 in plasma free

fatty acid showed a negative

relationship with fatness. The relationship between the plasma proportion

of 18[ratio ]2n-6 and fatness was

not observed after 48 h of fasting; instead, the plasma proportion of

18[ratio ]0 was found to be positively

related to fatness in the fasted state. In summary, this paper shows

how plasma and adipose tissue

fatty acid profiles differ, and it quantifies the effects of

selection on the plasma profiles. Possible

reasons for the difference in fatty acid profiles between adipose

tissue and plasma are discussed in the

paper. It is suggested that plasma 18[ratio ]2n-6 levels during the

early post-weaning growth period should

be investigated as indicators of future fatness.
Controlled-temperature effects on cotton yield and fibre properties
Authors: LIAKATAS A. , ROUSSOPOULOS D. , WHITTINGTON W. J.
Published: July 2002

Temperature effects on cotton yield and fibre properties
of three cotton cultivars were determined.
Plants were grown in pots maintained in growth rooms at varying day and
night temperatures
representing seasonally constant or varying (C) or daily varying (V) regimes.

Yield and fibre characters responded to variation of daily
mean and amplitude of temperature.
Mean temperature reduction improved yield components, but
fibre length, uniformity, strength and
micronaire were increased by high, particularly high day,
temperatures. A large daily temperature
amplitude produced an intermediate number of flowers and the lowest retention
percentage.

Fruiting and yield were increased by reduction in temperature down to
the threshold mean
temperature of 22°C. However, V-regimes with a low
minimum temperature acted as a further drop
(below 22°C) of temperature and adversely affected these
characters. An adverse effect of low
minimum temperature combined with a moderate day temperature was observed
also on lint
percentage and fibre properties.

Varietal differences were more pronounced for highly heritable
characters such as fibre properties,
for which significant interactions between varieties and
temperature also occurred. Differences in
reproductive development were not sufficient to be of much practical importance.
Effects of reducing anthelmintic input upon growth and
faecal egg and larval counts in young farmed deer
grazing chicory (Cichorium intybus) and perennial
ryegrass (Lolium perenne)/white clover
(Trifolium repens) pasture
Authors: HOSKIN S. O. , BARRY T. N. , WILSON P. R. , CHARLESTON W. A. G. , HODGSON J.
Published: July 2002

A rotational grazing experiment using weaner deer was conducted at Palmerston North, New
Zealand, during the autumn, winter and spring, to compare the voluntary feed intake (VFI),
liveweight gain (LWG) and carcass production of deer grazing chicory with those grazing perennial
ryegrass/white clover pasture. Deer were either treated with anthelmintic at 3-weekly intervals (T) or
anthelmintic was withheld until trigger-treatment (TT) criteria were attained. Pure red and 0·75
red: 0·25 elk hybrid stags and hinds were given forage allowances of 5 kg DM/deer/day in autumn
and early-mid winter, 6 kg DM/deer/day in late winter and 7 kg DM/deer/day in spring. Deer
grazed chicory or pasture in autumn and spring, with all deer combined on pasture during winter
when chicory was dormant. Organic matter digestibility of diet selected was greater for chicory than
for pasture in both autumn and spring.

Anthelmintic-treated deer grazing pasture in autumn had significantly higher VFI and LWG,
contributing to higher carcass weights, than TT deer. Anthelmintic treatment had no effect on these
measures for deer grazing chicory in autumn. Clinical signs of lungworm infection were evident in
pasture TT deer during autumn and winter, and in chicory TT deer grazing pasture during winter.
Faecal egg counts (FEC) were significantly greater for pasture TT deer during autumn and early
winter than all other groups. Faecal lungworm larval counts (FLC) were significantly greater for
chicory TT deer following transfer to pasture, than for all other groups in early winter, although both
FEC and FLC were low. Faecal larval counts were poorly related to clinical signs of lungworm
infection during autumn, but were a better guide in winter. Plasma pepsinogen concentrations
appeared unrelated to gastrointestinal parasite infection. Trigger-treated deer grazing pasture
required five anthelmintic treatments during autumn and winter. The chicory TT group required no
anthelmintic treatment when grazing chicory during autumn, but required two treatments after
transfer from chicory to pasture during winter.

There was no effect of anthelmintic regime on VFI and LWG in spring, and LWG was greater for
deer grazing chicory than those grazing pasture. Hybrid deer had greater spring LWG and carcass
weights than red deer when grazing chicory, but similar LWG and carcass weights when grazing
pasture.

It was concluded that grazing chicory offers the potential for reducing anthelmintic use in farmed
weaner deer, particularly during autumn.
Sprout and top-shoot cutting for rapid multiplication
of potato in Bangladesh
Authors: HOSSAIN M. J. , NAHAR M. S. , AHMAD A. U.
Published: July 2002

The combined effect of two rapid multiplication techniques (sprout and top-shoot cutting) was
assessed using four Dutch potato cultivars during 1991/92–1993/1994 at the Tuber Crops Research
Centre (TCRC), Bangladesh Agricultural Research Institute (BARI), Gazipur-1701, Bangladesh. On
average, a 70–80 g tuber produced 29 sprout cuttings which were subsequently used for taking top-shoot cuttings. Top-shoot cuttings were taken at a number of dates from 25 November and continued
at 10 day intervals, thereafter, until 15 January. The number of top-shoot cuttings produced by 29
sprout cutting-derived plants varied (P<0·01) from 761 to 663 across the cultivars. Cardinal gave
the greatest yield. Most of the characters studied varied (P<0·01) between cultivars but not over
years while the interaction between cultivars and years was significant (P<0·01).

Early planted top-shoot cuttings produced more tubers per plant (4·0) with a greater mean tuber
weight (>22 g) than from the late planting (1 tuber and 5·5 g). On average, about 2·8 tubers per plant
were produced with a mean tuber weight of 15·8 g. Cardinal and Patrones produced the most tubers
per plant (2·9) and Diamant the greatest mean tuber weight (16·8 g). Cardinal gave the greatest yield
(P<0·01) of tubers (268) followed by Patrones (241). The 29 sprout cutting plants derived from a
70±5 g tuber produced 160 tubers while the 771 top-shoot plants derived from 29 sprout cutting-derived plants produced 1420 tubers. The rate of multiplication of the combined two RM techniques
was 1580[ratio ]1 against 11[ratio ]1 for the conventional method.
Pollination requirements of West Indian cherry
(Malpighia emarginata) and its putative pollinators,
Centris bees, in NE Brazil
Authors: FREITAS B. M. , ALVES J. E. , BRANDÃO G. F. , ARAUJO Z. B.
Published: July 2002

The pollination requirements of West Indian cherry (Malpighia emarginata DC) were investigated in
NE Brazil through observations of flower morphology, floral rewards, anthesis, anther dehiscence,
stigma receptivity, pollen cross and self-compatibility and proportion of fruit set. Potential insect
pollinators and their foraging behaviour were also studied, and the pollination efficiency of the most
frequent flower visitor, the bee Centris tarsata Smith (Anthophoridae), was assessed using single visits
to flowers. It was shown that the West Indian cherry flower has a short lifespan, thus requiring
pollination on the day of anthesis, when both cross- and self-pollen grains set fruit. The flower can
potentially be pollinated by an array of insect visitors, but only oil-collecting bees of the genus Centris
find it very attractive. Centris tarsata appeared as the main pollinator of West Indian cherry in the
area studied, and farmers are advised to encourage its presence in orchards. Despite high levels of
natural pollination, only 30% of flowers set fruits. It is suggested that a high proportion of abnormal
ovule development may be responsible for low fruit set where pollination is satisfactory, and that
West Indian cherry varieties showing a lower percentage of such abnormalities should be selected for.
Effects of parasitic status and level of feeding
motivation on the diet selected by sheep grazing
grass/clover swards
Authors: HUTCHINGS M. R. , GORDON I. J. , ROBERTSON E. , KYRIAZAKIS I. , JACKSON F.
Published: July 2002

An experiment was carried out to determine the effects of parasitic status and level of feeding
motivation on the diet selected by sheep grazing perennial ryegrass/white clover swards. Twenty-four
female Scottish Blackface weaned lambs were divided into four treatment groups each of six animals.
Pre-grazing treatments were imposed to create two levels of feeding motivation, low (fed ad libitum)
and high (0·60 of ad libitum diet) and two parasitic states, parasitized (daily dose of 2500 L3Ostertagia
circumcincta) and non-parasitized. Each treatment group was placed in one of four 0·35 ha field plots
and allowed to graze a mixed grass/clover sward. Mean clover height was manipulated pre-grazing
by cutting so that it was less than the mean grass height. This maximized the probability that clover
in the diet of sheep was due to selection. No fertilizer was added to the sward in order to ensure that
the nitrogen content of the clover was higher than that of the grass. Each treatment group was rotated
around the four plots on a daily basis for 2 weeks. Sheep with a high feeding motivation strongly and
significantly selected clover and had a higher proportion of clover in their diet compared with sheep
with low feeding motivation. Parasitic status had no significant effect on the diet selection of sheep;
but the level of parasitic burden within parasitized sheep was positively correlated with the
proportion of clover in the diet. Parasitized sheep spent less time grazing each day and had lower daily
herbage intakes compared with non-parasitized sheep. This was a result of a reduction in the duration
of feeding bouts and not a reduced number of bouts per day. Sheep with the higher feeding
motivation had a greater number of feeding bouts per day and this resulted in those animals having
a greater daily herbage intake. Level of feeding motivation had greater effects on the diet selection
of sheep than parasitic status. Sheep with a high feeding motivation are able to select strongly for
clover in their diet when there is low overall clover availability and are capable of dramatically
affecting the species composition of a sward. This has implications to the maintenance of a desired
grass/clover ratio in grazed swards.
FERTILITY AND MORTALITY DIFFERENTIALS AMONG SELECTED TRIBAL POPULATION GROUPS OF NORTH–WESTERN AND EASTERN INDIA
Authors: KAPOOR A. K. , KSHATRIYA GAUTAM K.
Published: July 2002

Selection potential based on differential fertility and mortality has been computed for six tribal groups inhabiting different geo-climatic conditions, namely: Sahariya, Mina and Bhil of the State of Rajasthan, north-western India, and Munda, Santal and Lodha of the State of West Bengal, eastern India. Irrespective of the methodology, the total index of selection was found to be highest among Lodhas (0·668), followed by Sahariyas (0·524), Santals (0·462), Bhils (0·386), Mundas (0·353) and Minas (0·334). Incidently, Lodha and Sahariya are two of the seventy-four notified primitive tribal groups of India, and these two study populations show the highest index of total selection, mainly because of a higher embryonic and postnatal mortality.

The relative contribution of the fertility component to the index of total selection is higher than the corresponding mortality component in all tribal groups.

The analysis of postnatal mortality components indicates that childhood mortality constitutes the bulk of postnatal mortality, suggesting that children under 5 years need better health care in these tribal groups.
DETERMINANTS OF CONTRACEPTIVE USE AND METHOD CHOICE IN TURKEY
Authors: KOC ISMET
Published: July 2002

In this study, the determinants of contraceptive use and method choice are examined based on various variables, classified as individual, cultural, fertility and contextual. The data used came from the 1993 Turkish Demographic and Health Survey. The main finding is that there exists a positive association between the educational level of both spouses and the use of contraceptive methods in Turkey. After all individual, cultural, fertility and contextual variables are controlled, a woman's education is a stronger predictor of method use and method choice than that of her husband. Increasing the educational level of women may be the most effective means of advancing family planning acceptance and increasing the demand for contraceptive services in Turkey. The study also shows that, to a great extent, contraceptive use and choice of modern method depend on the sex of a couple’s living children, implying some preference for sons, although generally women prefer to have children of both sexes.
GENDER RELATIONS: HUSBAND–WIFE FERTILITY AND FAMILY PLANNING DECISIONS IN KENYA
Authors: KIMUNA SITAWA R. , ADAMCHAK DONALD J.
Published: July 2002

Although Kenya’s fertility rate has declined from 6·7 births per woman in the mid-1980s to 5·4 births per woman in 1993 (NCPD, 1994), population growth is still high, yielding a doubling time of 35 years. This study uses the 1993 Kenya Demographic Health Survey data collected from 1257 couples to examine the socioeconomic and sociodemographic characteristics of married men and women and their communication with their spouses over fertility and family planning decision-making practices. The logistic regression analysis shows that education for both men and women, discussion of fertility and family planning between spouses, male approval of use of contraception and male family size desires are important factors that influence ever-use of family planning.
BIODEMOGRAPHIC STUDY OF A CENTRAL APENNINE AREA (ITALY) IN THE 19TH AND 20TH CENTURIES: MARRIAGE SEASONALITY AND REPRODUCTIVE ISOLATION
Authors: ENRICA DANUBIO MARIA , AMICONE ELISA
Published: July 2002

This study investigates seasonality of marriages and reproductive isolation in six long-isolated communities in the central Apennines (Italy). It had two objectives: (1) the identification of an Apennine biodemographic model in comparison with mountain communities of other regions, and with non-Apennine communities in Abruzzo, and (2) to identify the possible effects of the drainage of Lake Fucino (1854–1876) on that area. Marriages in this region show two very stable seasonal patterns: one is typical of sedentary rural societies, with summer migrations and marriages preferentially celebrated in the winter, and the other has marriages that are strongly concentrated in the summer months, i.e. between 75% and 93·5% of marriages were celebrated between June and October in these communities in the 1800s. These were traditionally pastoral communities with winter transhumance of the flocks and their shepherds towards the lowlands of southern Italy. In both groups, restrictions imposed by the Catholic Church do not seem to have affected the timing of marriages. Indeed, economic factors related to work activities seem to have had more influence. Concerning reproductive isolation, the results show high rates of endogamy: between 85% and 98% in both the 19th and 20th centuries. Rates of consanguineous marriages were between 5% and 20%, and those of isonymous marriages rarely exceeded 9%. The coefficient of inbreeding α shows that there was a delayed, limited period of increased consanguinity in the few decades around the turn of the century. This is different from the national situation, and thus could be a consequence of the Lake Fucino drainage.
POSTPARTUM AMENORRHOEA IN RURAL EASTERN UTTAR PRADESH, INDIA
Authors: YADAVA K. N. S. , JAIN S. K.
Published: July 2002

This paper calculates the mean duration of the postpartum amenorrhoea (PPA) and examines its demographic, and socioeconomic correlates in rural north India, using data collected through 'retrospective' (last but one child) as well as 'current status' (last child) reporting of the duration of PPA.

The mean duration of PPA was higher in the current status than in the retrospective data;n the difference being statistically significant. However, for the same mothers who gave PPA information in both the data sets, the difference in mean duration of PPA was not statistically significant. The correlates were identical in both the data sets. The current status data were more complete in terms of the coverage, and perhaps less distorted by reporting errors caused by recall lapse.

A positive relationship of the mean duration of PPA was found with longer breast-feeding, higher parity and age of mother at the birth of the child, and the survival status of the child. An inverse relationship was found with higher education of a woman, higher education of her husband and higher socioeconomic status of her household, these variables possibly acting as proxies for women's better nutritional status.
Chemiluminescence of bovine polymorphonuclear leucocytes during
the periparturient period and relation with metabolic markers and
bovine pregnancy-associated glycoprotein
Authors: HOEBEN DAGMAR , MONFARDINI ERICA , OPSOMER GEERT , BURVENICH CHRISTIAN , DOSOGNE HILDE , DE KRUIF AART , BECKERS JEAN-FRANÇOIS
Published: July 2002

The respiratory burst activity of polymorphonuclear leucocytes (PMN)
was evaluated in eight Holstein cows from 8 weeks before until 6 weeks after calving
by chemiluminescence (CL). The CL response started to decrease 1 week before
parturition, reaching a minimum during the first 2 weeks after calving. From week
3 of lactation, CL increased again and returned to original levels by week 6 of
lactation. Plasma concentrations of 3-hydroxybutyric acid, total bilirubin and
bovine pregnancy-associated glycoprotein started to increase before parturition to
reach a maximum during the first or second week of lactation. The concentrations of
glutamic–oxaloacetic transaminase, lactate dehydrogenase, non-esterified fatty acids
and bilirubin increased after calving, reaching a maximum during the second week.
A small decrease in plasma cholesterol during the week before and after calving was
followed by an increase. The CL response of the PMN showed significant temporal
relationships with the plasma concentrations of 3-hydroxybutyric acid, bovine
pregnancy-associated glycoprotein, bilirubin, glutamic–oxaloacetic transaminase,
non-esterified fatty acids; that with cholesterol was nearly significant. This means
that the change in the CL response with time coincided with the changes in plasma
concentrations of these substances with time and that these changes were
significantly related with each other. The results of this study show that the
decreased respiratory burst activity of bovine PMN around parturition may be
related to the extent of the metabolic and hormonal changes. Although the causative
relationships are not proven, these results support earlier results suggesting that
3-hydroxybutyric acid and bovine pregnancy-associated glycoprotein may directly
affect neutrophil function, whereas non-esterified fatty acids, cholesterol, bilirubin,
and liver enzymes may have potential as diagnostic markers of impaired neutrophil
function and consequently increased disease risk around parturition.
Characterization of peptides produced by the action of psychrotrophic proteinases on κ-casein
Authors: RECIO ISIDRA , GARCÍA-RISCO MÓNICA R. , RAMOS MERCEDES , LÓPEZ-FANDIÑO ROSINA
Published: July 2002

Psychrotrophic bacteria, capable of growing in milk during refrigerated storage
before processing, produce thermostable proteinases that strongly influence the
keeping quality of long life dairy products (Cousin, 1982). This is the case with UHT
milk, where the activity of residual or reactivated bacterial proteolytic enzymes is
linked to flavour deterioration and gelation. Furthermore, since most of these
enzymes are acid proteinases with a broad specificity and particularly active against
κ-casein (Fairbairn & Law, 1986), their hydrolysis products can interfere with
detecting the fraudulent addition of rennet whey (López-Fandiño et al. 1993a, b;
Recio et al. 1996, 2000). This is usually based upon detecting, by reversed-phase (RP-)
HPLC (Olieman & van Riel, 1989; Van Riel & Olieman, 1995a) or capillary
electrophoresis (CE) (Van Riel & Olieman, 1995b), caseinmacropeptide (CMP), the
106–169 fragment of κ-casein released by chymosin during the initial stages of
cheesemaking (for review, see López-Fandiño & Olano, 1999). Nevertheless, it is not
yet clear whether degradation of κ-casein by psychrotrophic enzymes gives rise to
hydrolysis products that are identical to those produced by chymosin or just
indistinguishable by CE (Van Riel & Olieman, 1995b; Recio et al. 1996).

In the present investigation, we studied CMP-like degradation products produced
by the action of extracellular psychrotrophic proteinases on κ-casein by RP-HPLC
and CE. Electrospray ionization–mass spectrometry (ESI–MS) was used for peptide
identification. Characterization of breakdown products specific to psychrotrophic
enzymes may help the investigation of their residual activity remaining in milk after
processing, as well as provide an indication of the suitability of CMP as an indicator
of adulteration of UHT milk with whey solids.
Survey of lactic acid bacteria isolated during the advanced stages
of
the ripening of Parmigiano Reggiano cheese
Authors: COPPOLA RAFFAELE , NANNI MAURO , IORIZZO MASSIMO , SORRENTINO ALIDA , SORRENTINO ELENA , GRAZIA LUIGI
Published: July 2002

Parmigiano Reggiano is a hard, cooked cheese produced in specific
areas of
Northern Italy. The raw material is obtained by mixing the partly skimmed
evening
milk and whole morning milk. The mixture is then heated to 22°C, and
natural whey
starter is added at 28–30 g/l after 1–2 min,
bringing the pH of the mixture to 6·2–6·3.
After coagulation, which takes ∼15 min and occurs at
32–33°C owing to the
addition of calf rennet powder, the curd is broken up for 2–4
min, cut into fragments
and cooked at a temperature raised gradually to 42–44°C
and then more quickly to
55–56°C over 10–15 min. The curd is left
undisturbed, covered by the whey, for
40–60 min, then removed and placed inside a circular
wooden mould. The cheese is
held at ∼20°C for 3 d during which it is turned at
frequent intervals to facilitate
complete whey drainage. The cheese, which now has its typical shape and
size, is then
salted by immersion in brine (260–280 g NaCl/l at
16–17°C) for 20–24 d. During this
period the cheese absorbs 15–18 g NaCl/kg and its
weight decreases by 4%. During
the subsequent period of ripening (12–24 months) in store
rooms at 16–18°C and
85% moisture, the cheese is frequently turned. At the end of ripening the
cheese is
cylindrical in shape, with a slightly convex side,
0·22–0·24 m high, 0·40–0·45 m diam.

weighs 35–36 kg, has 320–330 g fat/kg dry
matter and a minutely granulated
internal structure with small holes formed by the activity of some
heterofermentative lactic acid bacteria.
Electrophoretic characterization of the
protein products formed during heat treatment of whey
protein concentrate solutions
Authors: HAVEA PALATASA , SINGH HARJINDER , CREAMER LAWRENCE K. , CAMPANELLA OSVALDO H.
Published: July 2002

Whey protein concentrate (WPC) solutions containing
10, 30, 60 and
120 g dry powder/kg were heated at 75°C and whey
protein aggregation was studied
by following the changes in the distribution of
β-lactoglobulin, α-lactalbumin and
bovine serum albumin, using one dimensional and two
dimensional PAGE. The one
dimensional PAGE results showed that a minimal quantity
of large aggregates was
formed when 10 g WPC/kg solutions were heated at
75°C for up to 16 min whereas
appreciable quantities were formed when 30, 60 and 120 g
WPC/kg solutions were
similarly treated. The two dimensional PAGE analysis
showed that some disulphide-linked β-lactoglobulin
dimers were present in heated 10 g WPC/kg solution, but very
little was present in heated 120 g WPC/kg solution.
By contrast, SDS was able to
dissociate monomeric protein from high molecular mass
aggregates in heated WPC
solution of 120 g/kg but not in 10 g WPC/kg solution
heated for 30 min. The rates
of loss of native-like and SDS-monomeric β-lactoglobulin,
α-lactalbumin and bovine
serum albumin during heating increased as the WPC
concentration was increased
from 10 to 120 g/kg. In 120 g WPC/kg solution
heated at 75°C, the amounts of SDS-monomeric
β-lactoglobulin in each sample were greater than
the quantities of native-like protein. However, in WPC
solutions of 10, 30 and 60 g/kg, the differences
between the amounts of native-like and SDS-monomeric proteins
were slight. The
loss of the native-like or SDS-monomeric proteins was
consistent with a first or
second order reaction. In each case, the apparent reaction
rate constant appeared to
be concentration-dependent, suggesting a change of
aggregation mechanism in the
more concentrated solutions. Overall, these results
indicate that in addition to
disulphide-linked aggregates, hydrophobic aggregates
involving β-lactoglobulin, α-lactalbumin and
bovine serum albumin were formed in heated WPC solution at high
protein concentration, as suggested by model studies
using binary mixtures of these proteins.
Factors contributing to variation in the proportion of casein in
cows' milk true protein: a review of recent INRA experiments
Authors: COULON JEAN-BAPTISTE , HURTAUD CATHERINE , REMOND BERNARD , VERITE RAYMOND
Published: July 2002

The aim of this study was to identify and rank the various factors,
in
particular those involving feeding, that affect the proportion of caseins
in milk true
protein. Twenty-nine feeding trials involving 821 lactations were assessed,
and
lactoprotein genetic variants were known for 551 of these. The main factor
affecting
the casein: protein ratio was the genetic variant of β-lactoglobulin:
once corrected for
other factors, the milk of BB type animals had a ratio nearly 30 g/kg
total protein
higher than AA animals. κ-Casein variant B also had a positive effect
(+12 g/kg in
favour of BB relative to AA animals). Except in the last weeks of pregnancy
and the
first weeks of lactation, the casein[ratio ]protein ratio varied little
during lactation. It was
significantly reduced when milk cell count exceeded 200000 cells/ml,
even in the
absence of clinical mastitis. It also decreased slightly with parity. Among
the various
dietary factors studied (level and type of nitrogen and energy supplies,
forage type
and preservation method), none had any significant effect on the milk casein[ratio ]protein

ratio, except in drastic dietary situations. That ratio increased very
slightly in
parallel with the animals' milk yield and milk protein content. In
practice, measuring
the milk protein content in animals free from clinical mastitis remains
a very precise
predictor of casein content, accounting for 93% of its variation.
Effects of heat treatments and subsequent storage on the mineral
balance of ewes' milk
Authors: DE LA FUENTE MIGUEL ANGEL , OLANO AGUSTÍN , JUÁREZ MANUELA
Published: July 2002

The effects of heat treatment of ewes' milk at 65–85°C
for
10–30 min and subsequent storage at 20°C for 90 min on the changes
in ionic calcium
and the distribution of calcium, magnesium and phosphorus between the diffusible
and
micellar phases were studied. As milk was heated there was a decrease in
ionic
calcium of ∼36 mg/l, but there was a rapid 86–90% recovery
during the first
30 min after heating. Although the rate of reversal on subsequent storage
decreased with the
intensity of the heat treatment, there were no significant differences
between samples
after 90 min storage. Similar results were obtained for cows' milk
subjected to the
same treatments. Diffusible calcium, magnesium and phosphorus in heated
samples
were lower than in raw milk. Recoveries of initial values decreased with
the severity
of the heat treatment and were 80–95% for calcium, 85–97% for
magnesium and
87–98% for phosphorus. Heat treatment under milder conditions (85°C
for 20 s) was
associated with almost complete recoveries. Recoveries of the minerals
studied were
slightly lower in ewes' than in cows' milk.
Revisionism and the Irish Reformation
Authors: BOTTIGHEIMER KARL
Published: July 2002

The Irish Reformation remains a troubled subject, and not from
lack of recent scholarly attention. It has attracted an abundance
of high-quality work, but its vexed nature as a topic is illuminated
by a long, authoritative essay published in 1998 by Brendan Bradshaw,
one of the foremost students of early-modern Irish history. The essay is
entitled ‘The English Reformation and identity formation in Ireland and
Wales’, as befits the volume in which it appeared: British consciousness and
identity: the making of Britain, 1533–1707. But the pageheads of the sixty-nine-page article call it ‘The Reformation in Ireland’, and this is a much
more accurate description of its contents, as even its author might agree.

Whether denominated ‘The Irish Reformation’ or ‘The Reformation
in Ireland’, the event lacks the familiarity of historical chestnuts like the
Congress of Vienna or The Thirty-Years War, well-worn, frequently-taught subjects (at least in the old canon of European history) about
which there was a modicum of consensus, sufficient at least to allow them
to be discussed. But in order for events to be debated, there needs to be
agreement that they happened, and in that respect the Irish Reformation
is something of a non-starter.
Saltation and incipient suspension above a flat particle bed below a turbulent boundary layer
Authors: NISHIMURA K. , HUNT J. C. R.
Published: July 2002

Experiments were conducted in a wind tunnel in which a turbulent boundary layer
was naturally grown over flat beds of three types of nearly mono-disperse spherical
particles with different diameters, densities and coefficient of restitution (r) (snow,
0.48 mm, 910 kg m−3; mustard seeds, 1.82 mm, 1670 kg m−3,
r = 0.7; ice particles, 2.80 mm, 910 kg m−3, r = 0.8–0.9).
The surface wind speeds (defined by the friction
velocity u∗) were varied between 1.0 and 1.9 times the threshold surface wind speed
(defined by u∗t). The trajectories, and ejection and impact velocities of the particles
were recorded and analysed, even those that were raised only about one diameter into the flow.

Measurements of the average horizontal flux of saltating particles per unit area, f(z),
at each level z above the surface showed that, for
u∗/u∗t [les ] 1.5, f(z) is approximately
independent of the particle density and decreases exponentially over a vertical scale
length lf, that is about 3 to 4 times the estimated mean height of the particle
trajectories 〈h〉. Numerical simulations of saltating grains were computed using the
measured probabilities of ejection velocities and the mean velocity profile of the air
flow, but neglecting the direct effect of the turbulence. The calculated mean values
of the impact velocities and the trajectory dimensions were found to agree with the
measurements in the saltation range, where
u∗/u∗t < 1.5. Similarly, in this range
the simulations of the horizontal flux profile and integral are also consistent with the
measurements and with Bagnold's u∗3 formula, respectively.

When u∗/u∗t [ges ] 1.5, and
u∗/VT [ges ] 1/10, where VT
is the settling velocity, a transition
from saltation to suspension occurs. This is indicated by the change in the mean mass
flux profile which effectively becomes uniform with height (z) up to the top of
the boundary layer. An explanation is provided for this low value of turbulence
at transition relative to the settling velocity in terms of the random motion of
the particles under the action of the turbulence when they reach the tops of their
parabolic trajectories. The experiments show that, as u∗/u∗t
increases from 1.0 to 1.9 the normalized mean vertical impact velocity
〈V3I〉/u∗ decreases by nearly 60% to
about 0.6, which is less than 50% of the value for fluid particles. There is also a
decrease in the vertical and horizontal component of the ejection velocity to values
of 0.8 and 2.3, which are much less than their values in the saltation regime. We
hypothesize that at the transition from saltation to suspension the ejection process
changes quite sharply from being determined by impact collisions to being the result
of aerodynamic lift forces and upward eddy motions.
High-speed flow with discontinuous surface
catalysis
Authors: AMARATUNGA S. R. , TUTTY O. R. , ROBERTS G. T.
Published: July 2002

In a reacting gas flow both gas-phase chemical activity and surface catalysis can increase the rate of heat transfer from the gas to a solid surface. In particular, when there is a discontinuous change in the catalytic properties of the surface, there can be a very large increase in the local heat transfer rate. In this study numerical simulations have been performed for the laminar high-speed flow of a high-temperature, non-equilibrium reacting gas mixture over a flat plate. The surface of the plate is partly catalytic, with the leading region non-catalytic, and a discontinuous change in the catalytic properties of the surface at the catalytic junction. The surface is assumed to be isothermal, and cold relative to the free stream. The gas is assumed to be a mixture of molecular and atomic forms of a diatomic gas in an inert gas forming a thermal bath, giving a three-species mixture with dissociation and recombination of the reactive species. The calculations are performed for a gas with atomic and molecular oxygen in an argon bath, but a full range of gas-phase chemical and surface
catalytic effects is considered. Kinetic schemes with frozen gas-phase chemistry, and partial or full recombination of atomic oxygen in the boundary layer are investigated.
The catalytic nature of the surface material is given by a catalytic recombination
rate coeffcient, which varies from zero (non-catalytic) to one (fully catalytic), and the effects on the flow and the surface heat transfer of materials which are non-, partially, or fully catalytic are considered. A self-similar thin-layer analytical model of the change in the gas composition downstream of the catalytic junction is developed. For physically realistic (O(10−2)) values of the catalytic recombination rate coeffcient, the
predictions from this model of the surface values of the atomic oxygen mass fraction
and the catalytic surface heat transfer rate are excellent when the only change in the composition of the gas comes from the surface catalysis, and reasonable when there is partial recombination of the gas in the boundary layer due to the gas-phase chemistry. In contrast, when the surface is fully catalytic, the streamwise diffusion terms play a significant role, and the model is not valid. These results should apply to other situations with an attached boundary layer with recombination reactions. A comparison is made between the calculated and experimental measurements of the heat transfer rate at the catalytic junction. With a kinetic scheme which allows partial recombination in the boundary layer, good agreement is found between the experimental and predicted values for surface materials which are essentially non-catalytic. For a catalytic material (platinum), the experimental and numerical heat transfer rates are matched to estimate the value of the catalytic recombination rate coeffcient. The values obtained show a considerable amount of scatter, but are consistent with those found in the literature.
Linear stability analysis of mixed-convection flow in a vertical pipe
Authors: SU YI-CHUNG , CHUNG JACOB N.
Published: July 2002

A comprehensive numerical study on the linear stability of mixed-convection flow
in a vertical pipe with constant heat flux is presented with particular emphasis on
the instability mechanism and the Prandtl number effect. Three Prandtl numbers
representative of different regimes in the Prandtl number spectrum are employed
to simulate the stability characteristics of liquid mercury, water and oil. The results
suggest that mixed-convection flow in a vertical pipe can become unstable at low
Reynolds number and Rayleigh numbers irrespective of the Prandtl number, in
contrast to the isothermal case. For water, the calculation predicts critical Rayleigh
numbers of 80 and −120 for assisted and opposed flows, which agree very well
with experimental values of Rac = 76 and −118 (Scheele & Hanratty 1962). It
is found that the first azimuthal mode is always the most unstable, which also
agrees with the experimental observation that the unstable pattern is a double spiral
flow. Scheele & Hanratty's speculation that the instability in assisted and opposed
flows can be attributed to the appearance of inflection points and separation is
true only for fluids with O(1) Prandtl number. Our study on the effect of the
Prandtl number discloses that it plays an active role in buoyancy-assisted flow and
is an indication of the viability of kinematic or thermal disturbances. It profoundly
affects the stability of assisted flow and changes the instability mechanism as well.
For assisted flow with Prandtl numbers less than 0.3, the thermal–shear instability
is dominant. With Prandtl numbers higher than 0.3, the assisted-thermal–buoyant
instability becomes responsible. In buoyancy-opposed flow, the effect of the Prandtl
number is less significant since the flow is unstably stratified. There are three distinct
instability mechanisms at work independent of the Prandtl number. The Rayleigh–Taylor
instability is operative when the Reynolds number is extremely low. The
opposed-thermal–buoyant instability takes over when the Reynolds number becomes
higher. A still higher Reynolds number eventually leads the thermal–shear instability
to dominate. While the thermal–buoyant instability is present in both assisted and
opposed flows, the mechanism by which it destabilizes the flow is completely different.
Transient response of a compressible fluid in a rapidly rotating circular pipe
Authors: PARK JUN SANG , HYUN JAE MIN
Published: July 2002

The transient adjustment process of a compressible fluid in a rapidly rotating pipe is
studied. The system Ekman number E is small, and the assumptions of small Mach
number and the heavy-gas limit (γ = 1.0) are invoked. Fluid motion is generated
by imposing a step-change perturbation in the temperature at the pipe wall Tw.
Comprehensive analytical solutions are obtained by deploying the matched asymptotic
technique with proper timescales O(E−1/2) and
O(E−1). These analytical solutions are
shown to be consistent with corresponding full numerical solutions. The detailed
profiles of major variables are delineated, and evolution of velocity and temperature
fields is portrayed. At moderate times, the entire flow field can be divided into two
regions. In the inner inviscid region, thermo-acoustic compression takes place, and
the process is isothermal–isentropic with the angular momentum being conserved.
In the outer viscous region, diffusion of angular momentum occurs. The principal
dynamic mechanisms are discussed, and physical rationalizations are offered. The
essential differences between the responses of a compressible and an incompressible
fluid are highlighted.

The issue of stability of the analytically obtained flow is addressed by undertaking
a formal stability analysis. It is illustrated that, within the range of parameters of
present concern, the flow is stable when ε ∼ O(E).
The anatomy of the mixing transition in homogeneous and stratified free shear layers
Authors: CAULFIELD C. P. , PELTIER W. R.
Published: July 2002

We investigate the detailed nature of the ‘mixing transition’ through which turbulence
may develop in both homogeneous and stratified free shear layers. Our focus is
upon the fundamental role in transition, and in particular the associated ‘mixing’
(i.e. small-scale motions which lead to an irreversible increase in the total potential
energy of the flow) that is played by streamwise vortex streaks, which develop once
the primary and typically two-dimensional Kelvin–Helmholtz (KH) billow saturates
at finite amplitude.

Saturated KH billows are susceptible to a family of three-dimensional secondary
instabilities. In homogeneous fluid, secondary stability analyses predict that the stream-wise vortex streaks originate through a ‘hyperbolic’ instability that is localized in the
vorticity braids that develop between billow cores. In sufficiently strongly stratified
fluid, the secondary instability mechanism is fundamentally different, and is associated
with convective destabilization of the statically unstable sublayers that are created as
the KH billows roll up.

We test the validity of these theoretical predictions by performing a sequence of
three-dimensional direct numerical simulations of shear layer evolution, with the
flow Reynolds number (defined on the basis of shear layer half-depth and half
the velocity difference) Re = 750, the Prandtl number of the fluid Pr = 1, and
the minimum gradient Richardson number Ri(0) varying between 0 and 0.1. These
simulations quantitatively verify the predictions of our stability analysis, both as to
the spanwise wavelength and the spatial localization of the streamwise vortex streaks.
We track the nonlinear amplification of these secondary coherent structures, and
investigate the nature of the process which actually triggers mixing. Both in stratified
and unstratified shear layers, the subsequent nonlinear amplification of the initially
localized streamwise vortex streaks is driven by the vertical shear in the evolving
mean flow. The two-dimensional flow associated with the primary KH billow plays
an essentially catalytic role. Vortex stretching causes the streamwise vortices to extend
beyond their initially localized regions, and leads eventually to a streamwise-aligned
collision between the streamwise vortices that are initially associated with adjacent
cores.

It is through this collision of neighbouring streamwise vortex streaks that a final
and violent finite-amplitude subcritical transition occurs in both stratified and
unstratified shear layers, which drives the mixing process. In a stratified flow with
appropriate initial characteristics, the irreversible small-scale mixing of the density
which is triggered by this transition leads to the development of a third layer within
the flow of relatively well-mixed fluid that is of an intermediate density, bounded by
narrow regions of strong density gradient.
Downstream and upstream influence in river meandering. Part 2. Planimetric development
Authors: SEMINARA G. , ZOLEZZI G. , TUBINO M. , ZARDI D.
Published: July 2002

The exact solution of the problem of river morphodynamics derived in Part 1 is
employed to formulate and solve the problem of planimetric evolution of river
meanders. A nonlinear integrodifferential evolution equation in intrinsic coordinates
is derived. An exact periodic solution of such an equation is then obtained in terms
of a modified Fourier series expansion such that the wavenumbers of the various
Fourier modes are time dependent. The amplitudes of the Fourier modes and their
wavenumbers satisfy a nonlinear system of coupled ordinary differential equations
of the Landau type. Solutions of this system display the occurrence of two possible
scenarios. In the sub-resonant regime, i.e. when the aspect ratio of the channel is
smaller than the resonant value, meandering evolves according to the classical picture:
a periodic train of small-amplitude sine-generated meanders migrating downstream
evolve into the classical, upstream skewed, train of meanders of Kinoshita type.
Evolution displays all the experimentally observed features: the meander growth rate
increases up to a maximum and then decreases, while the migration speed decreases
monotonically. No equilibrium solutions are found. In the super-resonant regime the
picture is essentially reversed: downstream skewing develops while meanders migrate
upstream.

Numerical solutions of the planimetric evolution equation are obtained for the
case when the initial channel pattern exhibits random small perturbations of the
straight configuration. Under these conditions, the evolution displays the typical
features of solutions of the Ginzburg–Landau equation, in particular, the occurrence
of spatial modulations of the meandering pattern which organizes itself in the form of
wavegroups. Furthermore, multiple loops develop in the advanced stage of meander
growth.
Mixing in flows down gentle slopes into stratified environments
Authors: BAINES PETER G.
Published: July 2002

Observations of the flow of dense fluid into uniformly density-stratified environments
down plane slopes with small inclination to the horizontal ([les ] 20°) are described, and
a quantitative model for such flows is presented. In these experiments the dense fluid
is released at the top of the slope for a finite period of time. The resulting downslope
gravity current, or downflow, has uniform thickness with a distinct upper boundary,
until it approaches its level of neutral density where the fluid leaves the proximity of the
slope. Turbulent transfers of mass and momentum occur across the upper boundary,
causing a continuous loss of fluid from the downflow in most cases, and associated loss
of momentum. The flow may be characterized by the local values of the Richardson
number Ri, the Reynolds number Re (generally large), and of
M = QN3/g′2, where Q
is the (two-dimensional) volume flux, N the buoyancy frequency and g′ the (negative)
buoyancy of the dense fluid. The model for the downflow describes the turbulent
transfers in terms of entrainment, detrainment and drag coefficients,
Ee, Ed and k
respectively, and the observations enable the determination of these coefficients in
terms of the local values of M and Ri. The model may be regarded as an extension
of that Ellison & Turner (1959) to stratified environments, describing the consequent
substantial changes in mixing and distribution of the inflow. It permits the modelling
of the bulk properties of these flows in geophysical situations, including shallow and
deep flows in the ocean.