bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of supplementation and stocking rate on body condition and production parameters of multiparous beef cows
Authors: Renquist B. J. , Oltjen J. W. , Sainz R. D. , Connor J. M. , Calvert C. C. 
Published: April 2006

AbstractFall-calving multiparous Angus × Hereford cows 3 to 10 years of age were stratified by age in a three by two factorial treatment arrangement to evaluate the efficacy of modifying stocking rate and supplementation strategy to manage cow body condition and production parameters over a 5-year study. Efficacy was evaluated quarterly in association with calving, breeding, weaning, and mid way between weaning and calving (i.e. in August). Three protein supplementation strategies (none, standard, strategic) were imposed across both a moderate (0·3 cows per ha) and a high (0·4 cows per ha) stocking rate. In the strategically supplemented group, protein supplement was provided to cows with a body condition score <5·5 at the quarterly evaluations. There was an effect of supplementation on pregnancy rate, which in combination with previously established culling practices resulted in different age profiles amongst supplementation strategies in years 2 to 5 (P < 0·01). Two statistical analyses were therefore conducted to dissociate the confounding effects of supplementation strategy and age. One model included the effect of stocking rate, supplementation strategy, production year, and all interactions; the second included the addition of age and its interactive effects. Stocking rate and supplementation strategy affected pregnancy rate in each of the models (P = 0·003 and P = 0·10, respectively). Standard, non-supplemented and strategically supplemented animals had estimated pregnancy rates of 0·83, 0·76, and 0·79, respectively (P = 0·10). The effects of nutrition on both calving interval and birth weight were independent of the model employed. Animals that were not supplemented had extended calving intervals (P = 0·06), but there was no effect of stocking rate (P > 0·10). Birth weight was not affected by supplementation strategy or stocking rate (P > 0·10). The lower 205-day weights of calves on a heavy compared with moderate stocking rate was independent of age (P = 0·02). However, the increased 205-day weight of calves born to strategically supplemented cows compared with those born to unsupplemented cows was only evident when data were not corrected for differences in age among groups (P = 0·03). Likewise, analyses of cow condition parameters using models without and with age resulted in different interpretations. These results suggest that strategic and standard supplementation result in similar animal performance and that the improvement in herd productivity associated with altering stocking rate and supplementation may partially be due to altered herd age dynamics.
Investigating environmental variation and landscape characteristics of an urban–rural gradient using woodland carabid assemblages
Authors: Sadler J. P. , Small E. C. , Fiszpan H. , Telfer M. G. , Niemelä J. 
Published: April 2006

AbstractAim To investigate environmental variation and associated assemblage changes of carabid beetles along an urban–rural gradient.Location ‘Quercus–Acer’ (oak–sycamore) woodlands in the city of Birmingham, UK.Methods We collected carabid data using pitfall traps on 12 sites in the city. The traps were run from April–September in 2000, and we collected environmental data on 24 individual variables associated with the individual sites and their landscape context. Changes in carabid assemblages were analysed using repeat measuresanovaand the environment–species relationships with a Redundancy Analyses (RDA) and Generalized Linear Modelling (GLM).Results We found that: (1) species richness and diversity were lower in the urban and suburban zone and higher in the rural zone; (2) Berger Parker dominance index was higher in the urban and suburban zones; (3) the number of woodland and woodland associated species was significantly higher at the rural end of the gradient; (4) the number of short‐winged (brachypterous) species was highest in the rural zone and decreased towards the urban woodlands, whereas the long‐winged species were more abundant in suburban woodlands; (5) the median weight length (WML) of the assemblage declined along the gradient from the rural to the urban zone, as did the number of large species; and (6) five of the 24 environmental variables showed a significant relationship with variation in the carabid assemblage. At site level the carabid assemblages were related to the level of site disturbance and soil penetrability, whereas site size and amount of woodland and urban land within 5 km of the site were important at a larger landscape scale.Main conclusions The results suggest that urbanization has a deleterious impact on carabid assemblages, causing a reduction in species richness from the rural fringe to the centre of the city. Changes in assemblage structure were related to woodland fragmentation, which led to variations in woodland size, woodland location and site disturbance due to trampling. Large, flightless and specialist woodland species are more susceptible to changes associated with urbanization, presumably due to their longer life spans, lower reproductive rates, more specialized niches and more limited dispersal potential.
Geographical expansion and increased prevalence of common species in avian assemblages: implications for large‐scale patterns of species richness
Authors: La Sorte Frank A. 
Published: April 2006

AbstractAim The assumption that ecological patterns at large spatial scales originate exclusively from non‐anthropogenic processes is growing more questionable with the increasing domination of the biosphere by humans. Because common and rare species are known to respond differently to anthropogenic activities at local scales these differential responses could, over time, be reflected in distributional patterns of species richness at larger spatial scales. This work tests the hypothesis that modern processes have played a role in shaping these patterns, by examining recent changes in the structure and composition of assemblages of breeding avifauna over a large geographical extent.Location The portion of North America containing the contiguous United States and southern Canada.Methods Changes in the geographical range structure of breeding avifauna in North America from 1968 to 2003 were analysed in regions containing historically moderate levels of anthropogenic activities. Two geographical measures, extent of occurrence and area of occupancy, were used to identify the level of rarity or commonality of individual species and to estimate, based on a vector analysis, patterns of change in geographical range structure for individual species and avian assemblages.Results More species experienced patterns of geographical range expansion (51%) than contraction (28%). The majority of avian assemblages (43%) displayed patterns of geographical range expansion: common species increased in number and proportion (6%) in association with reciprocal losses in rare and moderately rare species, resulting in a constant level of species richness. The minority of avian assemblages (21%) displayed patterns of geographical range contraction: gains occurred for common species as well as for rare and moderately rare species, resulting in substantial increases in species richness and a decline in the proportion of common species (4%). The remaining avian assemblages presented equivocal patterns characterized by gains in the number and proportion (2%) of common species and gains in species richness.Main conclusions Modern processes have played a role in shaping the distribution patterns of species richness at large spatial scales based on the composition of common and rare species. This suggests that anthropogenic activities cannot be ignored as a possible causal factor when considering ecological patterns at large spatial scales.
Assessing the effects of stimulation versus microswitch‐based programmes on indices of happiness of students with multiple disabilities
Authors: Lancioni G. E. , Singh N. N. , O’Reilly M. F. , Oliva D. , Smaldone A. , Tota A. , Martielli G. , Stasolla F. , Pontiggia G. , Groeneweg J. 
Published: April 2006

AbstractBackground  Stimulation and microswitch‐based programmes are considered main strategies to promote indices of happiness in students with multiple disabilities. However, only limited attempts have been made to assess the relative effects of the two programmes. This study conducted such an assessment with seven students with multiple disabilities.Methods  The first four phases of the study served to: (1) provide the students with a systematic exposure to each of the programmes; and (2) measure the programmes’ effects on indices of happiness by comparing them with baseline levels. The fifth phase served to compare the programmes with each other.Results  The first four phases of the study showed that the microswitch‐based programme produced a significant increase in indices of happiness for all seven students, and the stimulation programme produced a significant increase for six students. During the fifth phase of the study (i.e. when the two programmes were alternated), the microswitch‐based programme promoted significantly higher indices of happiness than the stimulation programme for four of the seven students.Conclusions  Microswitch‐based programmes might be deemed preferable to stimulation programmes because they can promote higher or comparable indices of happiness while promoting the acquisition of adaptive responses and self‐determination.
Heterozygote excess in a self‐incompatible and partially clonal forest tree species —Prunus avium L.
Authors: STOECKEL SOLENN , GRANGE JÉRÔME , FERNÁNDEZ‐MANJARRES JUAN F. , BILGER ISABELLE , FRASCARIA‐LACOSTE NATHALIE , MARIETTE STÉPHANIE 
Published: April 2006

AbstractWild cherry (Prunus avium L.), a partially asexual self‐incompatible forest tree, shows heterozygote excess, which is a poorly studied phenomenon. In three natural populations, we found significant heterozygote excess at almost all investigated loci (eight microsatellites and markers for the self‐incompatibility locus). We examined four hypotheses to account for this observed heterozygote excess. First, negative FIS can result from a lack of selfed progeny in small populations of outcrossing species. A second explanation for negative FIS is selection during the life cycle of the most heterozygous individuals. A third explanation is negative assortative mating when reproduction occurs between individuals bearing phenotypes more dissimilar than by chance. The last explanation for negative FIS relies on asexual reproduction. Expectations for each hypothesis were tested using empirical data. Patterns of FIS differed among loci. Nevertheless, our experimental results did not confirm the small sample size hypothesis. Although one locus is probably under a hitch‐hiking effect from the SI locus, we rejected the effect of the self‐incompatibility locus for the genome as a whole. Similarly, although one locus showed a clear pattern consistent with the selection of heterozygous individuals, the heterosis effect over the whole genome was rejected. Finally, our results revealed that clonality probably explains significant negative FIS in wild cherry populations when considering all individuals. More theoretical effort is needed to develop expectations and hypotheses, and test them in the case of species combining self‐incompatibility and partially asexual reproduction.
Global phylogeography of the scalloped hammerhead shark (Sphyrna lewini)
Authors: DUNCAN K. M. , MARTIN A. P. , BOWEN B. W. , DE COUET H. G. 
Published: April 2006

AbstractLarge marine fishes typically have little population genetic structure. The exceptions are associated with sedentary behaviour, disjunct distributions, or reproductive philopatry. Scalloped hammerhead sharks (Sphyrna lewini) incorporate the contrasting traits of oceanic habitat (usually associated with high dispersal) and possible fidelity to nursery grounds (for reproductive females). To evaluate the expectations of these contrasting behaviours, we examined the global genetic structure of S. lewini based on collections (n = 271 individuals) from 20 nursery areas. A 548‐bp fragment of mitochondrial DNA control region revealed 22 polymorphic sites, 24 haplotypes, and three lineages distinguished by 2.56–3.77% sequence divergence. Coalescence analyses based on a provisional molecular clock indicate an origin in the Indo‐West Pacific with late Pleistocene radiations into the central Pacific (Hawaii) and eastern Pacific (Central America), as well as recent interchange between oceans via southern Africa. Population subdivisions are strong (overall ΦST = 0.749, P < 0.0001 and among oceans ΦST = 0.598, P < 0.0098). Genetic discontinuity within oceans (ΦST = 0.519, P < 0.0001) is primarily associated with oceanic barriers (migration across oceans M ≈ 0), with much less structure along continental margins (M > 10). We conclude that nursery populations linked by continuous coastline have high connectivity, but that oceanic dispersal by females is rare. Although we cannot rule out philopatry to natal nurseries, oceanic barriers appear to have a much stronger influence on the genetic architecture of this species and may indicate a mechanism for recent evolutionary radiations in the genus Sphyrna.
Spermicide, cryptic female choice and the evolution of sperm form and function
Authors: Holman L. , Snook R. R. 
Published: April 2006

Abstract
Sperm competition and cryptic female choice profoundly affect sperm morphology, producing diversity within both species and individuals. One type of within-individual sperm variation is sperm heteromorphism, in which each male produces two or more distinct types of sperm simultaneously, only one of which is typically fertile (the ‘eusperm’). The adaptive significance of nonfertile ‘parasperm’ types is poorly understood, although numerous sperm-heteromorphic species are known from many disparate taxa. This paper examines in detail two female-centred hypotheses for the evolution and maintenance of this unconventional sperm production strategy. First, we use game theoretical models to establish that parasperm may function to protect eusperm from female-generated spermicide, and to elucidate the predictions of this idea. Second, we expand on the relatively undeveloped idea that parasperm are used by females as a criterion for cryptic female choice, and discuss the predictions generated by this idea compared to other hypotheses proposed to explain sperm heteromorphism. We critically evaluate both hypotheses, suggest ways in which they could be tested, and propose taxa in which they could be important.
The fracture toughness of a ultrahigh carbon steel containing 1.5 wt% C
Authors: FERNÁNDEZ‐VICENTE A. , CARSÍ M. , PEÑALBA F. , RUANO O. A. 
Published: April 2006

ABSTRACTThermomechanical processing of ultrahigh‐carbon steels allows the attainment of spheroidized and pearlitic microstructures that show very different mechanical properties. Spheroidized microstructures are formed by proeutectoid and eutectoid carbide particles embedded in a ferrite matrix. The mean proeutectoid carbide particle size is larger than the mean eutectoid carbide particle size and is practically invariable with austenitizing temperature below 850 °C. Pearlitic microstructures exhibit prior austenite grain sizes and pearlite colony sizes which increase and interlamellar spacings which decrease as the austenitizing temperature increases above 850 °C. A proeutectoid carbide size distribution that remains basically constant with austenitizing temperature is also observed in these microstructures. Plane‐strain fracture toughness of spheroidized and pearlitic UHCS‐1.5C materials do not vary significantly with austenitizing temperature, being the average fracture toughness of about 40 MPa m1/2 and 30 MPa m1/2, respectively. The constancy of fracture toughness with austenitizing temperature of the spheroidized microstructures is attributed to the constancy of the mean proeutectoid and eutectoid carbide size. Austenite grain size, pearlite colony size, interlamellar spacing and undissolved proeutectoid carbide size are evaluated for the influence of fracture toughness associated with pearlitic microstructures. It is found that proeutectoid carbide is the microstructural parameter that controls fracture toughness of pearlitic microstructures. Austenite grain size, pearlite colony size and interlamellar spacing are considered to have a minor influence.
Beware the airway filter: deadspace effect in children under 2 years
Authors: CHAU ANTHONY , KOBE JEFF , KALYANARAMAN RAMAN , REICHERT CLAYTON , ANSERMINO MARK 
Published: April 2006

SummaryBackground : Filters are increasingly used in breathing circuits as they protect the circuit from contamination and facilitate humidification of inspired gas. The use of filters, however, can augment the anatomical deadspace. This can be significant in children because they have much smaller tidal volumes.Methods : Following institutional ethical approval, 20 healthy children <2 years of age who required tracheal intubation were recruited. Ventilation was adjusted to achieve an endtidal carbon dioxide (PEco2) of 4.6 kPa (35 mmHg) when sampled at the tracheal tube (TT) adapter. Following a 10‐min period of stabilization, an airway filter (22 ml) was introduced into the circuit. The respiratory rate (RR) was then adjusted to return PEco2 to 4.6 kPa (35 mmHg).Results : A mean increase in ventilation of 1.42 (0.38) l·min−1 was required to maintain a normal PEco2 level. Airway pressure and respiratory rate increased by 7.9 mmHg (4.6) and 19.8 breath·min−1 (8.7) respectively. The PEco2 and partial pressure of inspired carbon‐di‐oxide (PiCO2) measured from the TT adapter were higher than measured from the filter port. The mean increase was 3.6 (1.6) mmHg for PEco2 and 5.9 (3.9) mmHg for PiCO2.Conclusion : Amplified deadspace from airway filters results in a significant increase in ventilation needed to maintain a normal PEco2 in children <2 years of age with normal lungs. Sampling of PEco2 and PiCO2 from the filter significantly underestimates the effect of increased deadspace. The effect of increased deadspace may be predicted using a proposed mathematical model.
Anesthetic implications of the catastrophic antiphospholipid syndrome
Authors: BATRA YATINDRA K. , RAJEEV S. 
Published: April 2006

SummaryThe antiphospholipid antibody syndrome (or the anticardiolipin antibody syndrome) is characterized by the presence of autoantibodies. Its major association is with systemic lupus erythematosus. ‘Catastrophic’ antiphospholipid syndrome (CAPS) is defined as an accelerated form of APS usually resulting in multiorgan failure and can be precipitated by surgery. We present the case of a 12‐year‐old male child who presented for enucleation of his left eye for fungal endopthalmitis. This patient had a history of CAPS 2 months before surgery with myocardial, gastrointestinal, renal and laryngeal involvement that improved on aggressive treatment and was subsequently managed on an outpatient basis for 2 months before presenting for enucleation. To the best of our knowledge, this is the first case of CAPS in a child reported in the anesthetic literature. Further aspects of this puzzling condition and its anesthesia implications are discussed.
Prey selectivity of bacterivorous protists in different size fractions of reservoir water amended with nutrients
Authors: Jezbera Jan , Horňák Karel , Šimek Karel 
Published: April 2006

SummaryAn experiment designed to examine food preferences of heterotrophic nanoflagellates (HNF) grazing on bacterioplankton was performed in the freshwater Římov reservoir (Czech Republic). Water samples were size‐fractionated to obtain < 5 µm filtrate containing bacteria and HNF. To manipulate resource availability, < 5 µm treatments were incubated in dialysis bags submerged in the barrels filled with the unfiltered reservoir water amended with either orthophosphate or glucose or combination of both. We employed rRNA‐targeted probes to assess HNF prey preferences by analysing bacterial prey in HNF food vacuoles compared with available bacteria. Actinobacteria (the HGC69a probe) were avoided by HNF in all treatments. Cytophaga‐Flavobacterium‐Bacteroidetes bacteria (the CF319a probe) were positively selected mainly in treatments in which bacteria were heavily grazed, the < 5 µm treatments, but this trend was less pronounced towards the end of the study. The members of a small subcluster of Betaproteobacteria (the R‐BT065 probe) were mostly positively selected. The nutrient amendments differentially affected bacterioplankton dynamics in almost all treatments, and together with the size fractionation, altered HNF overall bacterivory as well as prey selection. Analyses of bacterivores in unfiltered treatments allowed to detect the effect of different protists on shifts in HNF selectivity observed in < 5 µm compared with unfiltered treatments.
Synergistic effects of conjugated linoleic acid and chromium picolinate improve vascular function and renal pathophysiology in the insulin‐resistant JCR:LA‐cp rat
Authors: Proctor S. D. , Kelly S. E. , Stanhope K. L. , Havel P. J. , Russell J. C. 
Published: April 2006

Aims:  Conjugated linoleic acid (CLA) is a natural constituent of dairy products, specific isomers of which have recently been found to have insulin sensitizing and possible antiobesity actions. Chromium is a micronutrient which, as the picolinate (CrP), has been shown to increase insulin sensitivity in animal models, including the JCR:LA‐cp rat. We tested the hypothesis that these agents may have beneficial synergistic effects on the micro‐ and macrovasculopathy associated with hyperinsulinaemia and early type 2 diabetes.Methods:  Insulin‐resistant cp/cp rats of the JCR:LA‐cp strain were treated with mixed isomers of CLA (1.5% w/w in the chow) and/or CrP at 80 µg/kg/day (expressed as Cr) from 4 weeks of age to 12 weeks of age. Plasma insulin, lipid and adiponectin levels, aortic vascular function, renal function and glomerular sclerosis were assessed.Results:  CLA administration reduced food intake, body weight and fasting insulin in JCR:LA‐cp rats. Plasma adiponectin levels were significantly elevated in rats treated with both CLA and CrP. Aortic hypercontractility was reduced and the relaxant response to the nitric oxide‐releasing agent acetylcholine (Ach) was increased in CrP‐treated rats. Striking reductions were also observed in the level of urinary albumin and the severity of glomerular sclerosis in rats treated specifically with CLA.Conclusions:  CLA and CrP have beneficial effects ameliorating several of the pathophysiologic features of an insulin‐resistant rat model. These supplements may be useful adjuncts in the management of patients with the metabolic syndrome and warrant further study.