bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of tractor wheel passes on herbage production from diploid and tetraploid ryegrass swards
Authors: FRAME J. , MERRILEES D. W. 
Published: April 2006

AbstractDiploid and tetraploid perennial ryegrass swards were managed under an intensive silage system over 3 years. The swards were subjected to five tractor wheel pass treatments to simulate combinations of silage operations in the field from cutting, tedding, lifting and fertilizing. Wheel tracking was applied uniformly over the swards after June, July, August and October cuts each year.Tractor wheel passes caused mean reductions in herbage dry matter (DM) yield during successive years of 14%, 6% and 9% compared with their absence, and frequent or delayed wheel passes affected yield more adversely than infrequent or undelayed wheel passes. Nitrogen and mineral concentrations in herbage and nutrient offtakes were also generally reduced but organic matter digestibility (OMD) was unaffected. Soil assessments each autumn showed that soil bulk density increased in the wheel‐pass treatments, particularly when frequently applied. The two sward types responded in a similar manner to the wheel‐tracking treatments, probably because they had similar cushioning capability, the disadvantage of the tetraploid in terms of fewer tillers in relation to the diploid being compensated for by larger tiller size. Soil compaction, with its adverse effect on sward growth vigour, and direct wheel damage to young regrowth will be lessened by minimizing wheel traffic on silage swards and undertaking operations over short rather than long periods.
The effect of partial replacement of grass silage with fresh grass on rumen fermentation characteristics and rumen outflow rates in cattle
Authors: MCKEE C. A. , CUSHNAHAN A. , MAYNE C. S. , UNSWORTH E. F. 
Published: April 2006

AbstractAn experiment was designed to examine the effects of partially replacing extensively fermented grass silage with varying proportions of fresh grass (0, 0–33, 0–67 and 100) on rumen fermentation, degradation of dry matter (DM) and rate of outflow of liquid and particulate phases from the rumen with four mature Limousin steers. The fresh grass had a higher pH and water‐soluble carbohydrate and lower ammonia‐N and lactic acid concentrations than the silage. Partial replacement of silage with fresh grass resulted in a reduction in rumen ammonia concentration, and in the proportion of rumen propionate, i‐butyrate and n‐valerate and an increase in the proportion of rumen acetate and in both die particulate and liquid outflow rates from the rumen. These changes in rumen fermentation parameters could account for increases in animal performance in situations in which grass silage is partially replaced with fresh grass.
Influence of irradiance on branch growth of white clover stolons in rejected areas within grazed swards
Authors: TEUBER N. , LAIDLAW A. S. 
Published: April 2006

AbstractDevelopment of white clover stolons (Trifolium repens) was compared when grown in rejected areas and in adjacent defoliated areas over 28 days in May ‐ June in continuously stocked grass/white clover swards. In the cut areas more branches were borne on stolons with more but shorter internodes and shorter petioles than in the rejected areas. Red (R)/far red (FR) ratio at the base of the cut sward was significantly higher than in the rejected sward.Five experiments were carried out in which red light‐emitting diodes (LEDs) supplied supplementary irradiation at the node of the youngest fully expanded leaf on white clover stolons growing in association with dense canopies of perennial ryegrass. Axillary bud/branch length was the only significantly affected aspect of development that was measured, irradiation enrichment increasing length by about three‐fold over a 2–4 week period. One of the experiments involved identification of the site of perception of the R/FR effect. Natural and supplementary light were excluded from the stolon (by covering with a 2‐cm layer of black beads), petiole (by wrapping in aluminium foil), both or neither and showed that exposure of the stolon/ petiole base to supplementary light was necessary to stimulate axillary bud growth.It is concluded that the relative content of red light, and possibly absolute level, in irradiance at the base of the canopy in rejected areas is implicated in the young branch growth and that release of the buds can be achieved by defoliation, presumably due to increasing the red light content; however, the effect of increased photosynthetically active radiation (PAR) reaching stolons and young leaves cannot be discounted as an additional factor.
The intake of grass and rush (Juncus effusus L.) by goats grazing rush‐infested grass pasture
Authors: MERCHANT M. 
Published: April 2006

AbstractThe intakes of rush and grass by goats grazing rush‐infested reseeded pasture (rush ground cover, 5.9%) were measured in three periods between July and September in one year, using n‐alkanes as dietary markers. Diet composition and intakes were measured at intertussock sward heights maintained at 3–4 cm and 5–6 cm and at an intertussock sward height maintained at 3–4 cm where the rushes had previously been grazed by goats to reduce rush green stem height to 0.75 of that of ungrazed tussocks.There was no effect of intertussock sward height or initial rush green stem height on the dietary proportion (overall mean 0.51) or dry matter (DM) intake of rush but there was an effect of period, which was related to changes in sward conditions over the experiment. Rush intake was positively related to the amount and accessibility of green rush stems and grass intake to intertussock sward height. Digestibility of DM of the diet, measured using n‐alkanes, was high (overall mean 0.71), suggesting that the nutritive value of the rush is greater than previously estimated from in vitro digestibility measurements. Under these conditions, it appears that the goats select a mixed diet and the results are consistent with animals selecting food items to maximize their rate of nutrient intake.
The effect of grazed sward height and stocking rate on animal performance and output from beef cow systems
Authors: WRIGHT I. A. , MAXWELL T. J. , RUSSEL A. J. F. , HUNTER E. A. , SIBBALD A. R. , HETHERINGTON R. A. , WHYTE T. K. 
Published: April 2006

AbstractDuring three consecutive summers, forty spring‐calving beef cows and their calves grazed perennial ryegrass‐dominant swards receiving 250 kg N ha−1 at one of two annual stocking rates [2.0 (SR 2.0) or 2.5 (SR 2.5) cows ha−1] and one of two sward heights [4–5 (LS) or 7–8 (HS) cm] in a 2 × 2‐factorial experiment, replicated twice. Sward heights were maintained from turn‐out in spring by weekly adjustment of the area grazed and herbage was cut for silage in June and again in August from the areas not grazed. After the second cut of silage there was no control of sward height. Calves were weaned in early October and cows removed from pasture and housed when sward heights fell to 4 cm in autumn. Cows were fed in groups a variable but measured quantity of silage during winter to achieve a body condition score of 2.0–2.25 at turn‐out the following spring.During the period of sward height control the cows on the HS treatment gained more live weight than those on the LS treatment (0.841 vs. 0.496 kg day−1; P<0.01) as did the calves (1.167 vs. 1.105; P<0.05). but the stocking rate treatment had no effect. From the time of second‐cut silage to the time of weaning and housing respectively, calves and cows gained more live weight on the SR 2.0 treatment because sward heights were higher. Reproductive performance of cows was not affected by treatment.The quantity of silage produced and consumed per cow was not affected by sward height treatment, but the SR 2.0 treatment produced significantly (P<0.001) more silage (1559 kg dry matter per cow) than the SR 2.5 treatment (833 kg dry matter per cow) and had higher winter silage requirements (1249 vs. 1153 kg dry matter per cow: P<0.05). The overall mean stocking rate at which winter fodder production and requirements would be in balance was calculated as 2.25 cows ha−1 but values were 1.86, 2.60 and 2.28 in each of the three years of the experiment.The results showed that it was possible to control sward height in temperate beef cow systems by adjusting the area available for grazing. Body condition score can be used as a means of determining the feeding levels required to manipulate body condition of cows over winter to achieve prescribed levels of body condition. The experimental approach allows the identification of the stocking rate at which self‐sufficiency in winter fodder can be achieved and the year‐to‐year variation associated with that stocking rate. This approach could be generalized if information on herbage growth rate were available, either from direct measurement or from predictive models.
Growth and water relations of field‐grown tall fescue as influenced by drought and endophyte
Authors: ELBERSEN H. W. , WEST C. P. 
Published: April 2006

AbstractField plots were established in autumn 1992 in which endophyte [Neotyphodium coenophialum Glenn. Bacon, Price and Hanlin (formerly Acremonium coenophialum)]‐infected (E+) and endophyte‐free (E−) isolines of three tall fescue [Festuca arundinacea Schreb.) genotypes were planted. Plants were subjected to three water‐withholding periods in 1993 and one in 1994, or were kept well watered throughout the experiment. There were no consistent endophyte effects for leaf elongation, tiller density or dry weight per tiller. There were genotype X endophyte interactions (P<001) for tiller density and shoot dry weight per area and genotype X water X endophyte interactions (P<005) for cumulative leaf elongation in 1993. These interactions indicated the highly specific effect of host genotype‐endophyte association on the expression of plant growth. Leaf rolling in the stressed treatments was more severe in E− than in E+ plants in 1993, but there were no differences in 1994, and stomatal conductance tended to be lower in E− than in E+ plants in 1993. Fractional water content of the lower 3 cm of the youngest fully developed leaf sheath was usually greater, and never less, in E+ than in E− plants. The leaf rolling and stomatal conductance results suggest that E− plants were more severely stressed in the summer after planting. Thus, the endophyte may induce greater water retention in the leaf sheath and therefore better protect the internal growing zone from lethal desiccation.
Forage production by two Lotus species as influenced by companion grass species
Authors: HOPKINS A. , MARTYN T. M. , JOHNSON R. H , SHELDRICK R. D. , LAVENDER R. H. 
Published: April 2006

AbstractA small‐plot experiment was carried out with grass‐lotus (Lotus spp.) swards on a lowland (185 m) clay‐soil site in S‐W England. Two species of lotus (Lotus corniculatus cv. Leo and L. pedunculatus, syn, L. uliginosus, cv. Maku) were each sown at 10 kg seed ha−1 with lour grass species each at two grass‐seed rates: Festuca pratensis at 6 or 3 kg ha−1 and Phleum pratense, Agrostis capillaris and Poa pratensis at 4 or 2 kg ha−1. Assessments were made over three harvest years (1992–94). during which no fertilizers were applied. Mean total herbage dry matter (DM) harvested from cv. Leo swards was 90 t ha−1 in year 1, 8–9 t ha−1 in year 2 and 4 0 t ha−1 in year 3. and from cv. Maku swards 6–6 t ha−1 in year 1. 8–9 t ha−1 in year 2 and 3–9 t ha−1 in year 3. Highest three‐year mean total yields were with F. pratensis as the companion grass (7–4 t ha−1 year−1), followed by Phleum pratense (7–0 t ha−1), A. capillaris (6–9 t ha−1) and Poa pratensis (6–2 t ha−1). The lower grass‐seed rate resulted in a greater proportion of lotus in the total harvested DM in year I. The higher grass‐seed rate resulted in higher yields from F. pratensis swards in year 1, but there were no significant effects for other species or in subsequent years. Lotus as a proportion of harvested DM declined from about 70% in year 1 to about 20% in year 3. The mean DM yield of lotus herbage in years 1, 2 and 3, respectively, was 5–5, 2–8 and 0–8 t ha−1 from cv. Leo swards, and 4–0, 3–3 and 0–8 t ha−1 from cv. Maku swards. Lotus herbage was of higher digestibility from cv. Leo [digestible organic matter (DOM) of 661 g kg−1 of lotus DM] compared with cv. Maku (551 g kg−1 DM). Mean N content of lotus herbage was 35 g N kg−1 DM. Digestibility of companion grass herbage was highest for Phleum pratense (557 g kg−1 DM) and lowest for A. capillaris (493 g kg−1 DM). It is concluded that lotus may be an alternative legume to white clover for low‐input, low‐fertility situations. However, further research is needed to evaluate its performance on different sites and under different management regimes, particularly grazing, and to overcome the apparent problems of its persistence.
Effects of cultivar and cutting frequency on dynamics of stolon growth and leaf appearance in white clover grown in mixed swards
Authors: ELGERSMA A. , FENGRUI LI 
Published: April 2006

AbstractThe hypothesis that dynamics of growth, branching of stolons and appearance of leaves are important for the persistence of white clover (Trifolium repens) in mixed swards was tested. The effect of cutting frequency and white clover cultivar on stolon and leaf dynamics was studied throughout the growing season in a field experiment. Mixtures of perennial ryegrass (Lolium perenne) and white clover cultivars with different leaf sizes, cvs. Alice, Gwenda and Retor, were evaluated for white clover persistence at two cutting frequencies. Stolon dynamics, stolon survival, leaf and node appearance rate, branching, flowering and stolon elongation rate were analysed and related to white clover content and yield.There were clear seasonal fluctuations in stolon and leaf characteristics. Stolon elongation rate and appearance rates of nodes, leaves and branches declined in autumn. Temperature and irradiation explained a major part of the variation of stolon elongation rate and leaf appearance rate and 25% of the variation in stolon branching rate.Significant and consistent differences in yield and botanical composition were found between mixtures. Mixtures with cv. Alice had the highest total and white clover yield and the highest white clover content, whereas mixtures with cv. Retor had the lowest yield and the lowest white clover content. Stolon elongation rate and stolon internode length were significantly higher in cv. Alice than in the other white clover cultivars, whereas cv. Retor had a significantly higher percentage of leaves with damage caused by insects and slugs than the other cultivars. Little support was found for the hypothesis that branching characteristics are a key component of competitive success in mixed pasture, as most measured branching characteristics were not associated with differences in white clover yield between cultivars and cutting regimes.
Endophytic fungi and alkaloid production in perennial ryegrass in Germany
Authors: OLDENBURG E. 
Published: April 2006

AbstractInfection withNeotyphodiumendophyte was detected in 33 of 38 ecotype populations ofLolium perenneoriginating from old grassland at four widespread sites in Germany. The frequency of individual infected plants of the different populations ranged mostly from 1% to 30%; a few populations showed higher infection levels, up to 80%. The contribution of endophyte‐positive plants to the biomass of the original swards was estimated to range from 1% to 34%.Concentrations of the indole alkaloid lolitrem B detected in the endophyte‐positive German ecotypes were similar to those in the endophyte‐positive cultivars‘Ellett’and‘Grasslands Nui', originating in New Zealand, when all were cultivated under the climatic conditions of northern Germany. A seasonal variation in lolitrem B concentrations was observed from 1993 to 1996. The highest concentrations, 0·8–1·4 mg kg−1dry matter of herbage, were recorded during the months of July and August. These concentrations were not considered to be sufficient to induce‘ryegrass staggers', a neurological disorder in grazing animals. It is concluded that further research is necessary to elucidate the implications of grass endophytes under the climatic conditions of Central Europe.
The cellular response to chromosome breakage
Authors: Longhese Maria Pia , Mantiero Davide , Clerici Michela 
Published: April 2006

SummaryDNA double‐strand breaks (DSBs) are among the most deleterious types of damage that can occur in the genome of eukaryotic cells because failure to repair them can lead to loss of genetic information and chromosome rearrangements. DSBs can arise by failures in DNA replication and by exposure to environmental factors, such as ionizing radiations and radiomimetic chemicals. Moreover, they might arise when telomeres undergo extensive erosion, leading to the activation of the DNA damage response pathways and the onset of apoptosis and/or senescence. Importantly, DSBs can also form in a programmed manner during development. For example, meiotic recombination and rearrangement of the immunoglobulin genes in lymphocytes require the generation of site‐ or region‐specific DSBs through the action of specific endonucleases. Efficient DSB repair is crucial in safeguarding genome integrity, whose maintenance in the face of DSBs involves branched signalling networks that switch on DNA damage checkpoints, activate DNA repair, induce chromatin reorganization and modulate numerous cellular processes. Not surprisingly, defects in these networks result in a variety of diseases ranging from severe genetic disorders to cancer predisposition and accelerated ageing.
Androgenetic alopecia: Does its presence change our perceptions?
Authors: Karaman Göksun Can , Dereboy Çiğdem , Dereboy Ferhan , Çarman Esra 
Published: April 2006

AbstractBackground  The aim of this study was to evaluate the effects of androgenetic alopecia on males with and without hair loss and to delineate the level of stress gained by this type of alopecia.Methods  Two hundred and 52 males (175 with hair loss, 77 without hair loss), between 16 and 72 years of age, participated in the study. A hair loss form (five questions for sociodemographical features, eight questions for dermatological features, eight questions for psychological evaluation) and a list of stressful life events were used.Results  Desire for treatment was significantly different between the participants with and without androgenetic alopesia (AGA; χ2 = 5.877, d.f. = 1, P = 0.015). Regardless of the presence of AGA, 61.4% accepted AGA as a natural condition with a solution that should be sought, 38.5% as a cause for increased attention, and 56.2% thought that the psychological effects of AGA would mostly be negative. The negative effects of their AGA on other family members, relationships with the opposite sex and occupation/academic life were considered by 37.1%, 43.0% and 36.3% of the participants, respectively. None of the psychological parameters differed significantly between the participants with and without AGA. A small portion (5%) of the variance in perception of stress (0.222 = 0.048) might be explained by the degree of alopecia.Conclusion  Social and cultural differences might alter perceptions concerning AGA regardless of its presence in an individual.
Stable International Environmental Agreements: An Analytical Approach
Authors: DIAMANTOUDI EFFROSYNI , SARTZETAKIS EFTICHIOS S. 
Published: April 2006

AbstractIn this paper we examine the formation of international environmental agreements (IEAs). We show that the welfare of the signatories does not increase monotonically with respect to the number of signatories. We provide an analytical solution of the leadership model. In particular, we find that if the number of countries is greater than four then there exists a unique stable IEA with either two, three, or four signatories. Furthermore, we show that the welfare of the signatories is almost at its lowest level when the IEA is stable. While in our model each country's choice variable is emissions, we extend our results to the case where the choice variable is abatement efforts.
On the Relative Equitability of a Family of Taxation Rules
Authors: MORENO‐TERNERO JUAN D. , VILLAR ANTONIO 
Published: April 2006

AbstractA taxation problem consists of collecting a given amount of taxes out of a population whose gross income vector is given. A tax rule R is more equitable than a rule R′ when the after‐tax income vector generated by R Lorenz dominates that generated by R′. In this paper, we present a one‐parameter family of tax rules whose members are fully ranked in terms of relative equitability, for any (finite) income distribution.
Employment, Social Mobility and Neighbourhood Effects: The Case of Sweden
Authors: MUSTERD SAKO , ANDERSSON ROGER 
Published: April 2006

AbstractIn science and in society at large, there is a big debate going on about the existence and potential impact of ‘neighbourhood effects’. The dominant question is: does the social composition of the neighbourhood have specific positive or negative effects on the career prospects of those who are living there? We seek to contribute to this debate by investigating the relationship between individual social mobility and the social composition of the residential environment. For that purpose we analysed new longitudinal Swedish data, which is available at the individual level. We particularly focused our attention on the employment careers of individuals in relation to the levels of employment or unemployment in their individual environments. Environment effects on social mobility were isolated, controlling for relevant variables that were available at the individual level. We were also able to control for changes in the environments over time. Individual longitudinal data could be used over the period 1991–9. The analyses revealed that their environment appears to have a moderate yet clear impact on the employment prospects of unemployed individuals. The academic relevance of the article is in its contribution to the theoretical underpinnings of the human–environment relationship; the societal relevance is to the area‐based policies and the housing policies aimed at social mixing, which are currently being developed in many places in the Western world.
Perceptions, Persecution and Pity: The Limitations of Interventions for Homelessness in Developing Countries
Authors: SPEAK SUZANNE , TIPPLE GRAHAM 
Published: April 2006

AbstractInterventions for homelessness in developing countries are frequently negative and unhelpful. They tend to exist in an environment of hostility, suspicion and apathy towards homeless people. This environment is cultivated and enhanced by negative and derogatory language and images used by politicians, the public and the media in their portrayal of homeless people as unemployed, beggars, drunks and criminals. Findings from a recently completed study of homelessness in nine developing countries suggest that this perception is largely false. This article argues that, until the popular misconception of homeless people is corrected, even the most well‐intentioned interventions will have little long‐term effect.