bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal-binding polymorphism in late embryogenesis abundant protein AtLEA4-5, an intrinsically disordered protein
Authors: French-Pacheco Leidys , Cuevas-Velazquez Cesar L. , Rivillas-Acevedo Lina , Covarrubias Alejandra A. , Amero Carlos
Published: June 2018

Late embryogenesis abundant (LEA) proteins accumulate in plants during adverse conditions and their main attributed function is to confer tolerance to stress. One of the deleterious effects of the adverse environment is the accumulation of metal ions to levels that generate reactive oxygen species, compromising the survival of cells. AtLEA4-5, a member of group 4 of LEAs inArabidopsis, is an intrinsically disordered protein. It has been shown that theirN-terminal region is able to undergo transitions to partially folded states and prevent the inactivation of enzymes. We have characterized metal ion binding to AtLEA4-5 by circular dichroism, electronic absorbance spectroscopy (UV–vis), electron paramagnetic resonance, dynamic light scattering, and isothermal titration calorimetry. The data shows that AtLEA4-5 contains a single binding site for Ni(II), while Zn(II) and Cu(II) have multiple binding sites and promote oligomerization. The Cu(II) interacts preferentially with histidine residues mostly located in the C-terminal region with moderate affinity and different coordination modes. These results and the lack of a stable secondary structure formation indicate that an ensemble of conformations remains accessible to the metal for binding, suggesting the formation of a fuzzy complex. Our results support the multifunctionality of LEA proteins and suggest that the C-terminal region of AtLEA4-5 could be responsible for antioxidant activity, scavenging metal ions under stress conditions while theN-terminal could function as a chaperone.
Effect of acute augmented feedback on between limb asymmetries and eccentric knee flexor strength during the Nordic hamstring exercise
Authors: Chalker Wade J. , Shield Anthony J. , Opar David A. , Rathbone Evelyne N. , Keogh Justin W.L.
Published: June 2018

Background

Hamstring strain injuries (HSI) are one of the most prevalent and serious injuries affecting athletes, particularly those in team ball sports or track and field. Recent evidence demonstrates that eccentric knee flexor weakness and between limb asymmetries are possible risk factors for HSIs. While eccentric hamstring resistance training, e.g. the Nordic hamstring exercise (NHE) significantly increases eccentric hamstring strength and reduces HSI risk, little research has examined whether between limb asymmetries can be reduced with training. As augmented feedback (AF) can produce significant acute and chronic increases in muscular strength and reduce injury risk, one way to address the limitation in the eccentric hamstring training literature may be to provide athletes real-time visual AF of their NHE force outputs with the goal to minimise the between limb asymmetry.

Methods

Using a cross over study design, 44 injury free, male cricket players from two skill levels performed two NHE sessions on a testing device. The two NHE sessions were identical with the exception of AF, with the two groups randomised to perform the sessions with and without visual feedback of each limb’s force production in real-time. When performing the NHE with visual AF, the participants were provided with the following instructions to ‘reduce limb asymmetries as much as possible using the real-time visual force outputs displayed in front them’. Between limb asymmetries and mean peak force outputs were compared between the two feedback conditions (FB1 and FB2) using independentt-tests to ensure there was no carryover effect, and to determine any period and treatment effects. The magnitude of the differences in the force outputs were also examined using Cohendeffect size.

Results

There was a significant increase in mean peak force production when feedback was provided (mean difference, 21.7 N; 95% CI [0.2–42.3 N];P= 0.048;d= 0.61) and no significant difference in between limb asymmetry for feedback or no feedback (mean difference, 5.7%; 95% CI [−2.8% to 14.3%];P= 0.184;d= 0.41). Increases in force production under feedback were a result of increased weak limb (mean difference, 15.0 N; 95% CI [1.6–28.5 N];P= 0.029;d= 0.22) force contribution compared to the strong limb.

Discussion

The results of this study further support the potential utility of AF in improving force production and reducing risk in athletic populations. While there are currently some financial limitations to the application of this training approach, even in high-performance sport, such an approach may improve outcomes for HSI prevention programs. Further research with more homogenous populations over greater periods of time that assess the chronic effect of such training practices on injury risk factors and injury rates are also recommended.
Wonders never cease: Descartes's Météores and the rainbow fountain
Authors: WERRETT SIMON
Published: July 2002

This essay argues that the material culture of the Renaissance garden played an important role in the development of Cartesian mathematical and mechanical philosophy. Garden machinery such as Salomon and Isaac de Caus's automata and grottoes provided a model from which Descartes drew his clockwork conceptions of nature and the human body. This machinery was also crucial in the Cartesian explanation of the rainbow. Not simply an exercise in intellectual curiosity, Descartes's geometrical description of the rainbow in Discourse Eight of the Météores was a direct response to the engineers of artificial rainbow fountains which populated European princely gardens for much of the sixteenth and early seventeenth centuries. Rejecting distinctions between ‘natural’ and ‘artificial’ rainbows, Descartes used these fountains and his own constructions of artificial water drops to discern the causes of the rainbow by refraction and reflection and, by analogy, to suppose this the explanation of rainbows in the sky. This knowledge was then utilized to propose an alternative to the rainbow fountain, using refracting liquids to cast images in the sky. Descartes presented a ‘science of miracles’ destined not to eradicate wonder but to make transparent the wonders of traditional garden engineers and replace them with wonders derived from knowledge of mathematical and mechanical philosophy. As such, the ‘science of miracles’ gave a new emphasis to the mind of the natural philosopher as the essential component in the creation of wonders, rather than the traditional skills and experience of the artisan or engineer.
BJHS special section: book history and the sciences Introduction
Authors: TOPHAM JONATHAN R.
Published: July 2002

The expanding interest in book history over recent years has heralded the coming together
of an interdisciplinary research community drawing scholars from a variety of literary,
historical and cultural studies. Moreover, with a growing body of literature, the field is
becoming increasingly visible on a wider scale, not least through the existence of the
Society for the History of Authorship, Readership and Publishing (SHARP), with its newly
founded journal Book History. Within the history of science, however, there remains not
a little scepticism concerning the practical value of such an approach. It is often dismissed
as an intellectual fad or as an enterprise which is illuminating but ultimately peripheral,
rather than being valued as an approach which can offer major new insights within the
field. This is no doubt in part because much of the most innovative work in history of
science over recent years has been carried out by historians anxious to get away from an
earlier overemphasis on printed sources. Eager to correct a profoundly unsocial history of
ideas, usually rooted in texts, historians have looked increasingly to both the practices and
the material culture of science. In such a context, a renewed focus on the history of books
sometimes seems like a retrograde step, especially given the common misidentification of
‘books’ with ‘texts’. On the contrary, however, it is just such a twin emphasis on practices
and material culture which also characterizes the new book history. Indeed, to the question
‘what is book history for?’ we might answer that its object is to reintroduce social actors,
engaged in a variety of practices with respect to material objects, into a history in which
books have too often been understood merely as disembodied texts, the meaning of which
is defined by singular, uniquely creative authors, and is transparent to readers.
Review Article: North Urban Political Economy, Urban Theory and British Research
Authors: HARDING ALAN
Published: July 2002

In 1976, when European debates within urban theory were dominated by
neo-Marxist and neo-Weberian approaches to cities as sites for the provision of
social and welfare services, the very different notion of ‘the city as growth machine’ slipped into the US urban studies lexicon with the publication of Harvey Molotch's article of the same name. In 1983, the year in which Castells brought the radical phase of European urban studies to a halt with a famous warning against ‘the useless construction of abstract grand theory’, the concept of an urban regime had a similarly unobtrusive birth when the phrase was used by Fainstein and Fainstein to describe ‘the circle of powerful elected officials and top administrators’ in US city government. Had the story ended there it is unlikely that the world – especially outside North America – would have heard much more of urban regimes and growth machines. As it has turned out, though, from the late 1980s onwards urban scholars have hardly seemed able to hear enough about these two approaches within US urban political economy.
COMBINING RANKS AND SCORES TO DETERMINE FARMERS' PREFERENCES FOR BEAN VARIETIES IN SOUTHERN MALAWI
Authors: Abeyasekera S. , Ritchie J. M. , Lawson-McDowall J.
Published: July 2002

Ranking and scoring exercises are common in participatory research work, for example in determining farmer preferences for crop varieties, tree species or other commodities. However, they rarely involve eliciting opinions of many individual farmers so as to establish the repeatability of study findings. This paper demonstrates ways in which ranking of evaluation criteria can be combined with evaluation scores to produce generalizable results concerning farmers' overall preference for a set of bean (Phaseolus vulgaris) varieties. The use of weighted indices is explored. Results were found to be robust across all indices. However, farmer evaluations for yields did not correlate well with actual yields measured on their own plots. Farmers often gave high evaluation scores for yield performance of new bean varieties, even when they yielded quite poorly in plots in their own fields. Reasons for this are discussed.
Evidence for selection against tetraploid cells in tetraploid[harr ]diploid

mouse chimaeras before the late blastocyst stage
Authors: EVERETT CLARE A. , WEST JOHN D.
Published: July 2002

Tetraploid (4n) cells do not contribute equally to all tissues
of midgestation mouse chimaeras and
mosaics. Our previous studies of early blastocysts showed that 4n cells
are preferentially allocated
to the mural trophectoderm of the early blastocyst and this may contribute
to the restricted
distribution pattern seen at later stages. In this study of later-stage
blastocysts we found evidence
for selection against 4n cells. The contribution of 4n cells to 4n[harr ]2n
chimaeric blastocysts
decreased between E3·5 and E4·5 days, whereas the composition
of 2n[harr ]2n controls changed little
over this period. These results suggest that, prior to implantation, blastocysts
have already lost
some tetraploid cells from their embryonic and extra-embryonic lineages
due to a combination of
preferential allocation of 4n cells to the mural trophectoderm and selection
against 4n cells
throughout the embryo.
YOSEF GOVRIN, Israeli–Soviet Relations 1953–1967: From Confrontation to Disruption (London: Frank Cass, 1998). Pp. 347.
Authors: Freedman Robert O.
Published: July 2002

This book is a most welcome addition to the literature on Russian–Israeli relations. Although Yaacov Ro⊃i, in his study Soviet Decision Making in Practice: The USSR and Israel 1947–1954 (New Brunswick, N.J.: Transaction Books, 1980), covered the 1947–53 period thoroughly, and although there is an extensive body of literature on Russian policy toward Israel (and the rest of the Middle East) after the 1967 war, a gap has existed for many years in the scholarly coverage of Russian–Israeli relations from the death of Stalin in March 1953 until the June 1967 Six Day War. Yosef Govrin, a retired Israeli Foreign Office official who specialized in relations with the USSR, has gone a long way toward filling this gap. Having the advantage of access to the Israeli archives and internal political debates, Govrin presents a balanced picture of the Soviet–Israeli relationship, pointing out where, in his opinion, both Israel and the USSR made mistakes in developing their ties. He also goes into great detail on the question of Soviet Jewry (more than half of the book), noting how Israel's efforts to get the Soviet government to allow Jews to emigrate to Israel was a serious complicating factor in the relationship, although the primary cause for the USSR's breaking of diplomatic relations with Israel in June 1967 (Govrin was first secretary of the Israeli embassy in Moscow at the time) stemmed from Moscow's backing of the radical Ba⊃athist regime in Syria, which helped precipitate the 1967 war.
IDENTITY AND CHURCH: ETHIOPIAN–EGYPTIAN DIALOGUE, 1924–59
Authors: Erlich Haggai
Published: July 2002

In June 1959, Emperor Haile Sellassie of Ethiopia paid a visit to President Gamel Abdel Nasser of the United Arab Republic, during which the two leaders aired matters of acute strategic importance. Several issues, some touching the very heart of ancient Ethiopian–Egyptian relations, were in the stages of culmination. These included a bitter dispute over the Nile waters (some four-fifths of the water reaching Egypt originates in Ethiopia1), the emergence of an Arab-inspired Eritrean movement, Egyptian support of Somali irredentism, the Ethiopian alliance with Israel, the future of Pan-African diplomacy, and Soviet and American influences.2 Both leaders did their best to publicly ignore their conflicts. They were able to use a rich, though polarized, reservoir of mutual images in their speeches to emphasize the dimensions of old neighborliness and affinity.3 In a joint announcement issued during the farewell party of 28 June, they even underlined a common policy of non-alignment. Though they hinted at the issues mentioned earlier in all their public speeches, they refrained from referring to one culminating historical drama.4 On that very same day, in the main Coptic church of Cairo, the Egyptian Coptic Patriarch Kyrillos VI had ceremonially appointed the head of the Ethiopian church, Abuna Baselyos, as a patriarch in the presence of Haile Sellassie and Egyptian officials. In so doing, he declared the Orthodox Ethiopian church autocephalous, and for the first time since the early 4th century, the Ethiopian church had become independent of the Egyptian church.
Compulsory Arbitration and the Western Australian Gold-Mining Industry: A Re-Examination of the Inception of Compulsory Arbitration in Western Australia
Authors: Segal Naomi
Published: July 2002

In 1900, Western Australia, a self-governing British colony, adopted compulsory conciliation and arbitration legislation, the first Australian colony to do so. This article focuses primarily on the roles the colonial state and capital played in the adoption of the legislation and proposes a broader, more complex explanation for the introduction of the legislation than current mainstream Western Australian historiography, which, mostly, constructed the event as an unproblematic regional labour triumph. This article argues that the legislation was passed to prevent disruption to gold mining, the industry driving the development of the colony, and to revive the flagging political fortunes of the colonial government. It asserts that the timing of the legislation pre-empted a more effective bill being introduced under conditions less favourable to capital. Organized labour, which, through its lobbying, had created consensus about the desirability of introducing the legislation, was unable to influence the shape of the legislation significantly.
UNSETTLED ACCOUNTS: STOOL DEBTS, CHIEFTAINCY DISPUTES AND THE QUESTION
OF
ASANTE CONSTITUTIONALISM
Authors: BERRY SARA
Published: July 2002

In a recent study, Fred Cooper argues that strikes and other forms
of labor
protest had a clarifying effect on official thinking not only about labor
policies
but also about the aims and, ultimately, the viability of colonial rule.
As Africans went on strike, from the Copperbelt to the docks of Mombasa
and
the Gold Coast Railway, to demand better wages and working conditions,
colonial administrators first envisioned and then embraced the idea of
an
African working class and the possibility that African workers could be
managed with the same kinds of labor codes and social welfare policies
that
obtained in Europe.

Of course, the image of a working class applied only so far in Africa.
Colonial officials never fully understood the way African workers lived
or the
place of wage employment in African society, and were dismayed when their
newly acquired understanding of Africans as universal workers was challenged
in the 1950s by former strike leaders who began to insist on Africans'
rights to political autonomy. Nonetheless, as Cooper shows, the effects
of
recurrent, often highly effective, strikes were far-reaching. As officials
confronted the financial and political implications of providing all
Africans
with social welfare benefits and economic development comparable to those
of Europe, they decided it was time to abandon the imperial enterprise.
Interrelationships between amino acid and glucose metabolism in

lambs of different dietary history supplemented with rumen escape

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

Changes in amino acid and glucose metabolism in response to

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

lambs of three differing dietary histories and consequent weights,

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

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

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

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

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

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

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

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

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

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

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

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

lambs.

REP increased basal digestible organic matter intake (DOMI),

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

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

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

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

history group.

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

than in other lambs but was not significantly altered by REP

supplementation. Irreversible loss of glucose was greater (P <

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

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

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

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

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

lambs.

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

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

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

plasma growth hormone (GH) concentration. Plasma concentration of

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

while GH was not significantly affected by dietary history.

The results show that supplementation of ruminant diets with REP

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

of glucose utilization. Amino acid supply appears to influence

glucose utilization more through oxidation rate than supply, and this

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

and energy availability, either from the diet or from body

stores.
Nutrients and antiquality factors in different
morphological parts of the Moringa oleifera tree
Authors: MAKKAR H. P. S. , BECKER K.
Published: July 2002

Moringa oleifera grows throughout most of the tropics and has
several industrial and medicinal uses.
The objective of this study was to evaluate the potential of different
morphological parts of this tree
as animal feed. The crude protein (CP) content of leaves, soft twigs and stems
was 260, 70 and 60 g kg−1 respectively. About 64, 79 and
67% of the total CP present in the leaves, twigs and stems
respectively was found to be degradable after 24 h in the rumen. The protein
insoluble in acid
detergent fibre (ADIP), considered unavailable to animals, in these samples was
30, 150 and 170 g kg−1 respectively. About 87% of the total
CP was in the form of true protein in the leaves (60
and 53% in twigs and stems respectively). The leaves had negligible amounts
of tannins (12 g kg−1),
and trypsin and amylase inhibitors, lectins, cyanogenic glucosides and
glucosinolates were not
detected. The saponin content of the leaves was 80 g kg−1
as diosgenin equivalent, which did not show
any haemolytic activity. The phytate content of the leaves was
21 g kg−1. Tannins, saponins,
cyanogenic glucosides and glucosinolates were detected in twigs and stems
but the concentrations
were negligible. Trypsin and amylase inhibitors were not detected in twigs
and stems. Phytate
contents of both twigs and stems were c. 30 g k−1.
In leaves, amounts of all the essential amino acids
were higher than the amino acid pattern of the FAO reference protein
and comparable to those in
soyabeans. The CP and lipid contents of the kernel were 370 and
420 g kg−1 respectively, and the CP
of the meal (fat-free) was 610 g kg−1. The kernels and meal
are extracted with water and the extract
is used for the purification of water in some developing countries. The
residues left after water
extraction of kernels and meal (designated as extracted-kernel and
extracted-meal) had a CP content of 350 and 700 g kg−1
respectively and all of this CP was in the form of true protein. After taking into
account the ADIP contents in these samples, c. 38 and 69% of the
total protein was calculated to
be available in the post-rumen in extracted-kernel and extracted-meal
respectively. The pepsin
digestibility of these samples was 91 and 84% respectively. The
sulphur-containing amino acids in
kernel proteins were present at higher concentrations than those specified
in the amino acid pattern
of the FAO reference protein but other essential amino acids were
deficient. Amongst the
antinutritional factors mentioned above, glucosinolates and phytate were
present in appreciable amounts (65·5 μmol/g and
41 g kg−1
respectively) in meal. Haemagglutination activity was also
detected in the meal. The extracted-meal was virtually free of all the
antinutritional factors examined except for phytate (67 g kg−1).
The leaves of Moringa oleifera and the residue obtained after the
recovery of oil and coagulants can be good sources of proteins
for animal feeds.
Intake and digestibility of diets derived from stovers
and straws compared with lucerne hay and sweet
potato haulm
Authors: WILMAN D. , WEN LIAN , QIN HONGWEI , JI YILUN
Published: July 2002

In order to learn more about the feeding value of stovers and straws,
seven diets were compared in
one experiment and nine in another. The diets in the first experiment were:
the upper and lower parts
of lucerne (Medicago sativa) hay, the leaves, upper stem and lower
stem of maize (Zea mays) stover
and the leaves and stem of sorghum (Sorghum vulgare) stover. The
diets in the second experiment
were: the upper and lower parts of lucerne hay, the leaves, stem and whole
stover of millet (Setaria
italica), the straw and chaff of wheat (Triticum aestivum),
rice (Oryza sativa) straw and sweet potato
(Ipomoea batatas) haulm. The diets were fed to sheep to record
rate of intake, voluntary intake and
in vivo digestibility. The diets were analysed for cell wall (as
neutral detergent fibre), crude protein and
lignin. Organic matter degradation and cell wall degradation were recorded
in nylon bags in the
rumen of cattle.

The highest rates of intake (6·8–9·6 g dry matter/min)
and voluntary intake (75–103 g dry
matter/kg W0·75/day) were with sweet potato haulm
and the upper, leafy part of lucerne hay. The
voluntary intake of millet leaves, wheat chaff and the lower, stemmy part
of lucerne hay was
moderately high (46–70 g dry matter/kg W0·75/day).
Voluntary intake of leaves was higher than that
of stems in the case of millet, sorghum and to a lesser extent maize. The
lowest rates of intake were
with millet stem, sorghum stem and rice straw (1·8–2·4
g dry matter/min). In vivo digestibility of
organic matter was highest (59–67%) for the upper part of lucerne
hay, sweet potato haulm, the lower
part of maize stem and millet leaves. The leaves of maize were less digestible
than the stem, while the
reverse was the case with millet. Cell wall content was particularly high
(74–78% of dry matter) in
millet stem, wheat straw and chaff, rice straw and sorghum stem. Lignin
content was low (3·6–4·2%
of dry matter) in millet leaves, maize leaves and the upper part of maize
stem. Organic matter
degradation after 24 h incubation in the rumen was highest (80%) in sweet
potato haulm and lowest
(39–44%) in millet stem, wheat straw and chaff and rice straw. Cell
wall degradation after 96 h in the
rumen was highest (76–81%) with the leaves of maize, sorghum and
millet and lowest (40–59%) with
lucerne hay, millet stem and stover, wheat straw and chaff and rice straw.
Assessing the phosphorus status of winter wheat crops:
inorganic orthophosphate in whole shoots
Authors: BOLLONS H. M. , BARRACLOUGH P. B.
Published: July 2002

Winter wheat (Triticum aestivum L., cv Mercia) was grown at Rothamsted over three seasons
(1992/94/95) with plant-available soil P (Olsen-P) ranging from very deficient to superoptimal (1–52
mg P/kg; ADAS soil P Index 0–4). Critical Olsen-P for 95% maximum grain yield changed little
between years and averaged 9 mg P/kg. Total-P and inorganic-P (Pi) were measured in whole
shoots several times between late tillering and anthesis to see if Pi was a better indicator than total-P
of the adequacy of P supply for maximum grain yield. Inorganic-P accumulated in shoot tissue water
with increasing Olsen-P to a maximum concentration of c. 15 mM. Inorganic-P was a better indicator
of crop P status as there was less variation in critical values between seasons and with crop growth
stage. Expressing Pi concentrations on a tissue water basis (Piw) reduced the effect of differences in
soil water supply and also offers the prospect of in situ testing. Over the three seasons, critical shoot
Piw for 95% maximum grain yield averaged 4.7 mM (range 4·3–5·8 mM) during stem elongation.
Weeds and yields of spring cereals as influenced by
stubble-cultivation and reduced doses of
herbicides in five long-term trials
Authors: BOSTRÖM U. , HANSSON M. , FOGELFORS H.
Published: July 2002

The influence of herbicides at reduced rates and repeated stubble-cultivation on weeds and crop yields
was estimated in five field trials with spring-sown cereals situated in the south of Sweden during the
autumn of 1989 until the spring of 1997. Stubble-cultivation was accomplished during 1989–1996,
while herbicides were applied at 0, 1/8, 1/4 or 1/2 of full dose during 1990–1996.

In the spring of 1997, i.e. after 7 years without herbicide application, seedling densities 3 weeks after
weed emergence were 68–340/m2 at three sites and 535–610/m2 at two sites when averaged over tillage treatments.

Averaged over herbicide doses, stubble-cultivation reduced the plant density of annual broad-
leaved weeds by 6–32% at three sites and increased the density by 25% at one site. At the remaining
site, the density was not significantly influenced. Stubble-cultivation reduced the populations of two
perennial and seven annual weed species, while one species was stimulated and nine species showed
null, or inconsistent, responses. In the spring of 1997, i.e. one year after the last herbicide application,
the densities of weed seedlings in 1/8, 1/4 and 1/2-doses were 34, 46 and 56% lower, respectively,
than in the untreated controls.

Stubble-cultivation increased crop yields at four sites by 200 kg/ha as a mean over herbicide doses.
At these four sites, averaged over 1993–1995, herbicides increased yields in plots that were not
stubble-cultivated by 7, 8 and 10% in the 1/8, 1/4 and 1/2 of a full dose, respectively, relative to the
untreated control. In 1996, herbicides increased yields at only two sites.

It is concluded that a fruitful way for weed management with a low input of agrochemicals is to
combine the use of herbicides at reduced rates with repeated stubble-cultivation.
Confronting the Monolith:
Authority and the Cold War in
Gravity's Rainbow
Authors: HAMILL JOHN
Published: July 2002

One of the notable aspects of Gravity's Rainbow, if we consider it as an
historical novel of a special kind, is the way in which “great” political
leaders are barely mentioned. The carnival lacks the mock king, and the
historical novel lacks the leader who embodies history. The explanation
here is paradoxically historicist. Gravity's Rainbow explicitly addresses a
constructed audience (in the Orpheus Theatre) in the Cold War and is
about the formation of the Cold War in its techno-bureaucratic context. The
realpolitik of authority in the Cold War context has changed. Bureaucratic
constructions of System operate as the modus operandi for authority in the
novel and they parallel the historical formation of Systems theory and
analysis with such US organizations as RAND. This development
represents, in the technologies and the discourses of the military and
political strategists, a response to Hitler and the supposed tyranny and
threat of Communism. The series of characters we encounter within the
novel reflects different forms of entrapment and/or lines of flight in
response to the authority of the System in what John Johnston has called
an assemblage, or postmodern multiplicity. Containment and counterforce
become metaphors which Pynchon scurrilously uses to subvert the
moral righteousness of the Western Cold Warriors in their defense of a
“free world” (paradoxically) under siege from an ever threatening
Communism. Pynchon is interested not in the great historical figure, but
in the relation of the individual to the System, militarily, scientifically,
socially, and sexually.
THE ECOLOGY OF LOW NATURAL FERTILITY IN LADAKH
Authors: WILEY ANDREA S.
Published: July 2002

The existence of very low rates of fertility among non-contracepting human populations has intrigued researchers in demography and reproductive ecology. Long inter-birth intervals, driven primarily by the lactational amenorrhoea associated with breast-feeding, have been shown to be important determinants of low natural fertility in several populations. Other reports have suggested that sterility brought about by sexually transmitted diseases (STDs) might also explain low fertility in some populations, especially in Africa. This report presents an analysis of 1981 Indian census data that documents low natural fertility in Ladakh, a high-altitude region of the Himalaya in north India. In Ladakh, there is evidence for low rates of marriage among women that may be attributable to the practice of polyandry, but also high rates of primary and secondary sterility within marriage, resulting in low completed parities for post-reproductive age married women. Age-specific fertility rates derived from the number of current births are also unexpectedly low. Hypotheses to explain very low fertility in Ladakh are considered from among the likely proximate determinants and evaluated using two supplementary sources of information derived from fieldwork in Ladakh in the early 1990s. The most likely explanations for low marital fertility include sterility from STDs, high rates of fetal loss, and possibly nutritional contraints on ovarian hormone status.
Effects of the CSN1AG allele on the clotting time of cow milk and on the rheological properties of rennet-curd
Authors: MARIANI PRIMO , SUMMER ANDREA , DI GREGORIO PAOLA , RANDO ANDREA , FOSSA ENRICO , PECORARI MAURO
Published: July 2002

The aim of this research was to study the effects of the CSN1AG allele on
the main rennet coagulation properties of milk. The study was carried out on
individual milk samples with low αs1-casein obtained from 19 Italian Brown cows
heterozygous for the CSN1AG allele (seventeen CSN1A BG and two CSN1A CG) from
four herds in the province of Parma (Italy). Control cows (sixteen CSN1A BB and
three CSN1A BC) giving milk with normal αs1-casein levels were chosen from within
the same herds in order to establish pairs of cows with identical environment and
management conditions, and comparable lactation stages and numbers. Individual
milk samples from single pairs of cows with somatic cell counts and lactose and
chloride levels within the normal ranges were collected and analysed in parallel.
Rennet coagulation properties of milk were analysed using Formagraph and Gel
Tester. Milk from low αs1-casein cows was characterized by lower casein content,
lower titratable acidity and a higher proportion of κ-casein in total casein. The
clotting time of this milk was ∼ 23% lower than that obtained with milk from
normal αs1-casein cows. Rennet curd from low αs1-casein milk was obtained more
rapidly and had a higher final firmness: curd-firming time was ∼ 35% lower and
curd firmness measured 30 min after rennet addition was ∼ 27 % higher compared
with that for normal αs1-casein milk. In addition, curd from low αs1-casein milk had
a higher resistance to compression. These results suggest that, although a role for the
CSN2 locus cannot be definitely excluded, the CSN1AG allele can considerably affect
the main rennet coagulation properties of milk.
α1c- and β2-adrenergic receptor mRNA distribution in the bovine mammary gland detected by competitive RT-PCR
Authors: WELLNITZ OLGA , ZURBRIGGEN ANDREAS , FRIIS ROBERT R. , BLUM JÜRG W. , BRUCKMAIER RUPERT M.
Published: July 2002

Milk ejection and milk removal is considerably influenced by the sympathetic
nervous system. Stimulation of α-adrenergic receptors by administration of α-adrenergic
agonists inhibits alveolar milk ejection and milk removal in dairy cows
due to smooth muscle contraction (Blum et al. 1989; Bruckmaier et al. 1991).
However, contraction of the teat in response to α-adrenergic receptor stimulation has
no influence on milk flow as long as milk is available in the cistern (Bruckmaier et al.
1997). Therefore, α-adrenergic stimulation causes inhibition of transport of alveolar
milk into the cistern. On the contrary, the stimulation of β-adrenergic receptors
facilitates milk ejection and milk removal in dairy cows (Bernabé & Peeters, 1980;
Bruckmaier et al. 1991) because of muscle relaxation. Therefore, the distribution of
α- and β-adrenergic receptors plays an important role in the milkability of dairy
cows. However, from these in vivo studies it is not possible to distinguish between the
different α1- and α2- and β2-receptor subtypes owing to
the non-specific nature of the pharmacological agents used.

To date, the precise tissue distribution of these different subtypes, in bovine
mammary tissue, is unknown. Using molecular techniques, we were interested in the
expression of genes that encode α1c and β2 as a preliminary study towards the
understanding of noradrenergic receptor-gene expression and regulation in this
important system.

In addition, α1c- and β2-adrenergic receptors were determined in front and rear
quarters of the mammary gland to investigate differences in receptor distribution
within the udder and possible relations between adrenergic receptor distribution and
the higher milk flow rates in rear than in front quarters (Rothenanger et al. 1995).
Kicked Burgers turbulence
Authors: BEC J. , FRISCH U. , KHANIN K.
Published: July 2002

Burgers turbulence subject to a force f(x, t) =
[sum ]jfj(x)δ(t − tj), where tj are 'kicking times' and the 'impulses' fj(x) have arbitrary space dependence, combines
features of the purely decaying and the continuously forced cases. With large-scale
forcing this ‘kicked’ Burgers turbulence presents many of the regimes proposed by E
et al. (1997) for the case of random white-noise-in-time forcing. It is also amenable to
efficient numerical simulations in the inviscid limit, using a modification of the fast
Legendre transform method developed for decaying Burgers turbulence by Noullez
& Vergassola (1994). For the kicked case, concepts such as ‘minimizers’ and ‘main
shock’, which play crucial roles in recent developments for forced Burgers turbulence,
become elementary since everything can be constructed from simple two-dimensional
area-preserving Euler–Lagrange maps.

The main results are for the case of identical deterministic kicks which are periodic
and analytic in space and are applied periodically in time. When the space integrals of
the initial velocity and of the impulses vanish, it is proved and illustrated numerically
that a space- and time-periodic solution is achieved exponentially fast. In this regime,
probabilities can be defined by averaging over space and time periods. The probability
densities of large negative velocity gradients and of (not-too-large) negative velocity
increments follow the power law with −7/2 exponent proposed by E et al. (1997) in
the inviscid limit, whose existence is still controversial in the case of white-in-time
forcing. This power law, which is seen very clearly in the numerical simulations, is the
signature of nascent shocks (preshocks) and holds only when at least one new shock
is born between successive kicks.

It is shown that the third-order structure function over a spatial separation Δx
is analytic in Δx although the velocity field is generally only piecewise analytic (i.e.
between shocks). Structure functions of order p ≠ 3 are non-analytic at Δx = 0.
For even p there is a leading-order term proportional to [mid ]Δx[mid ] and for odd
p > 3 the leading-order term ∝Δx has a non-analytic correction
∝Δx[mid ]Δx[mid ] stemming from shock mergers.
On the long-term evolution of an intense localized divergent vortex on the beta-plane
Authors: REZNIK G. M. , GRIMSHAW R. , BENILOV E. S.
Published: July 2002

The evolution of an intense barotropic vortex on the β-plane is analysed for the case
of finite Rossby deformation radius. The analysis takes into account conservation of
vortex energy and enstrophy, as well as some other quantities, and therefore makes
it possible to gain insight into the vortex evolution for longer times than was done
in previous studies on this subject. Three characteristic scales play an important role
in the evolution: the advective time scale Ta (a typical time required for a fluid
particle to move a distance of the order of the vortex size), the wave time scale Tw
(the typical time it takes for the vortex to move through its own radius), and the distortion time scale
Td (a typical time required for the change in relative vorticity of the vortex to become
of the order of the relative vorticity itself). For an intense vortex these scales are well separated,
Ta [Lt ] Tw [Lt ] Td,
and therefore one can consider the vortex evolution as consisting of three different stages.
The first one, t [les ] Tw, is
dominated by the development of a near-field dipolar circulation (primary β-gyres)
accelerating the vortex. During the second stage,
Tw [les ] t [les ] Td, the quadrupole and
secondary axisymmetric components are intensified; the vortex decelerates. During
the last, third, stage the vortex decays and is destroyed. Our main attention is focused
on exploration of the second stage, which has been studied much less than the
first stage. To describe the second stage we develop an asymptotic theory for an
intense vortex with initially piecewise-constant relative vorticity. The theory allows
the calculation of the quadrupole and axisymmetric corrections, and the correction to
the vortex translation speed. Using the conservation laws we estimate that the vortex
lifetime is directly proportional to the vortex streamfunction amplitude and inversely
proportional to the squared group velocity of Rossby waves. For open-ocean eddies
a typical lifetime is about 130 days, and for oceanic rings up to 650 days. Analysis of
the residual produced by the asymptotic solution explains why this solution is a good
approximation for times much longer than the expected formal range of applicability.
All our analytical results are in a good qualitative agreement with several numerical
experiments carried out for various vortices.
Non-axisymmetric rotating-disk flows: nonlinear travelling-wave states
Authors: HEWITT R. E. , DUCK P. W.
Published: July 2002

We consider the classical problem of the laminar flow of an incompressible rotating
fluid above a rotating, impermeable, infinite disk. There is a well-known class of
solutions to this configuration in the form of an exact axisymmetric solution to the
Navier–Stokes equations. However, the radial self-similarity that leads to the ‘rotating-
disk equations’ can also be used to obtain solutions that are non-axisymmetric
in nature, although (in general) this requires a boundary-layer approximation. In
this manner, we locate several new solution branches, which are non-axisymmetric
travelling-wave states that satisfy axisymmetric boundary conditions at infinity and at
the disk. These states are shown to appear as symmetry-breaking bifurcations of the
well-known axisymmetric solution branches of the rotating-disk equations. Numerical
results are presented, which suggest that an infinity of such travelling states exist in
some parameter regimes. The numerical results are also presented in a manner that
allows their application to the analogous flow in a conical geometry.

Two of the many states described are of particular interest. The first is an exact,
nonlinear, non-axisymmetric, stationary state for a rotating disk in a counter-rotating
fluid; this solution was first presented by Hewitt, Duck & Foster (1999) and here we
provide further details. The second state corresponds to a new boundary-layer-type
approximation to the Navier–Stokes equations in the form of azimuthally propagating
waves in a rotating fluid above a stationary disk. This second state is a new non-axisymmetric alternative to the classical axisymmetric Bödewadt solution.
A model for the emergence of thermal plumes in Rayleigh–Bénard
convection at infinite Prandtl number
Authors: LEMERY C. , RICARD Y. , SOMMERIA J.
Published: July 2002

We propose a two-dimensional model of three-dimensional Rayleigh–Bénard
convection in the limit of very high Prandtl number and Rayleigh number, as in the
Earth's mantle. The model equation describes the evolution of the first moment of
the temperature anomaly in the thermal boundary layer, which is assumed thin with
respect to the scale of motion. This two-dimensional field is transported by the velocity
that it induces and is amplified by surface divergence. This model explains the
emergence of thermal plumes, which arise as finite-time singularities. We determine
critical exponents for these singularities. Using a smoothing method we go beyond
the singularity and reach a stage of developed convection. We describe a process of
plume merging, leaving room for the birth of new instabilities. The heat flow at the
surface predicted by our two-dimensional model is found to be in good agreement
with available data.
Longitudinal instabilities in an air-blasted liquid sheet
Authors: LOZANO ANTONIO , BARRERAS FÉLIX , HAUKE GUILLERMO , DOPAZO CÉSAR
Published: July 2002

An experimental and numerical study has been performed to improve the understanding
of the air/liquid interaction in an air-blasted breaking water sheet. This
research is focused in the near field close to the exit slit, because it is in this region
where instabilities develop and grow, leading to the sheet breakup. In the experiments,
several relevant parameters were measured including the sheet oscillation frequency
and wavelength, as well as the droplet size distribution and the amplification growth
rate. The flow was also investigated using linear instability theory. In the context
of existing papers on instability analysis, the numerical part of this work presents
two unique features. First, the air boundary layer is taken into account, and the
effects of air and liquid viscosity are revealed. Second, the equations are solved for
the same parameter values as those in the experiments, enabling a direct comparison
between calculations and measurements; although qualitatively the behaviour of the
measured variables is properly described, quantitative agreement is not satisfactory.
Limitations of the instability analysis in describing this problem are discussed. From
all the collected data, it is confirmed that the oscillation frequency strongly depends
on the air speed due to the near-nozzle air/water interaction. The wave propagates
with accelerating interface velocity which in our study ranges between the velocity
of the water and twice that value, depending on the air velocity. For a fixed water
velocity, the oscillation frequency varies linearly with the air velocity. This behaviour
can only be explained if the air boundary layer is considered.
A numerical comparison between the multiple-scales and finite-element solution for sound propagation in lined flow ducts
Authors: RIENSTRA SJOERD W. , EVERSMAN WALTER
Published: July 2002

An explicit, analytical, multiple-scales solution for modal sound transmission through
slowly varying ducts with mean flow and acoustic lining is tested against a numerical
finite-element solution solving the same potential flow equations. The test geometry
taken is representative of a high-bypass turbofan aircraft engine, with typical Mach
numbers of 0.5–0.7, circumferential mode numbers m of 10–40, dimensionless wavenumbers of
10–50, and both hard and acoustically treated inlet walls of impedance
Z = 2 − i. Of special interest is the presence of the spinner, which incorporates a
geometrical complexity which could previously only be handled by fully numerical
solutions. The results for predicted power attenuation loss show in general a very good
agreement. The results for iso-pressure contour plots compare quite well in the cases
where scattering into many higher radial modes can occur easily (high frequency, low
angular mode), and again a very good agreement in the other cases.