bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hip displacement in relation to age and gross motor function in children with cerebral palsy
Authors: Larnert Per , Risto Olof , Hägglund Gunnar , Wagner Philippe 
Published: March 2014

Purpose Hip dislocation in cerebral palsy (CP) is a serious complication. By radiographic screening and prophylactic surgery of children at risk most dislocations can be prevented. CPUP, the Swedish CP registry and follow-up program, includes annual radiographic examinations of children at Gross Motor Function Classification System (GMFCS) levels III–V. Data from CPUP were analysed to assess the risk of hip displacement in relation to GMFCS levels and age. Methods All children at GMFCS levels III–V ( N = 353) whose first radiographic screening occurred before 3 years of age were followed between the ages 2–7 years. Migration percentages (MPs) were recorded annually (1,664 pelvic radiographs) and analysed using discrete time survival analysis. Results The risk of hip displacement between 2 years and 7 years of age was significantly ( p < 0.05) higher for children at GMFCS level V during the entire study period. The risk was highest at 2–3 years of age and decreased significantly ( p < 0.001) with each year of age (OR = 0.71, 95 % CI 0.60–0.83). The cumulative risk at age 7 years for those at GMFCS V for MP ≥ 40 % was 47 % (95 % CI 37–58). The corresponding risk at GMFCS IV was 24 % (16–34) and at GMFCS III 23 % (12–42). Conclusions Children at GMFCS V have a significantly higher risk of hip displacement compared with children at GMFCS III–IV. The risk is highest at 2–3 years of age. The results support a surveillance program including radiographic hip examinations as soon as the diagnosis of severe CP is suspected.
Water entry without surface seal: extended cavity formation
Authors: Mansoor M. M. , Marston J. O. , Vakarelski I. U. , Thoroddsen S. T. 
Published: March 2014

AbstractWe report results from an experimental study of cavity formation during the impact of superhydrophobic spheres onto water. Using a simple splash-guard mechanism, we block the spray emerging during initial contact from closing thus eliminating the phenomenon known as ‘surface seal’, which typically occurs at Froude numbers $\mathit{Fr}= V_{0}^{2}/(gR_{0}) = O(100)$. As such, we are able to observe the evolution of a smooth cavity in a more extended parameter space than has been achieved in previous studies. Furthermore, by systematically varying the tank size and sphere diameter, we examine the influence of increasing wall effects on these guarded impact cavities and note the formation of surface undulations with wavelength $\lambda =O(10)~ \mathrm{cm}$ and acoustic waves $\lambda _{a}=O(D_{0})$ along the cavity interface, which produce multiple pinch-off points. Acoustic waves are initiated by pressure perturbations, which themselves are generated by the primary cavity pinch-off. Using high-speed particle image velocimetry (PIV) techniques we study the bulk fluid flow for the most constrained geometry and show the larger undulations ($\lambda =O (10~ \mathrm{cm}$)) have a fixed nature with respect to the lab frame. We show that previously deduced scalings for the normalized (primary) pinch-off location (ratio of pinch-off depth to sphere depth at pinch-off time), $H_{p}/H = 1/2$, and pinch-off time, $\tau \propto (R_{0}/g)^{1/2}$, do not hold for these extended cavities in the presence of strong wall effects (sphere-to-tank diameter ratio), $\epsilon = D_{0}/D_{tank} \gtrsim 1/16$. Instead, we find multiple distinct regimes for values of $H_{p}/H$ as the observed undulations are induced above the first pinch-off point as the impact speed increases. We also report observations of ‘kinked’ pinch-off points and the suppression of downward facing jets in the presence of wall effects. Surprisingly, upward facing jets emanating from first cavity pinch-off points evolve into a ‘flat’ structure at high impact speeds, both in the presence and absence of wall effects.
Mixing and transport by ciliary carpets: a numerical study
Authors: Ding Yang , Nawroth Janna C. , McFall-Ngai Margaret J. , Kanso Eva 
Published: March 2014

AbstractWe use a three-dimensional computational model to study the fluid transport and mixing due to the beating of an infinite array of cilia. In accord with recent experiments, we observe two distinct regions: a fluid transport region above the cilia and a fluid mixing region below the cilia tip. The metachronal wave due to phase differences between neighbouring cilia is known to enhance the fluid transport above the ciliary tip. In this work, we show that the metachronal wave also enhances the mixing rates in the sub-ciliary region, often simultaneously with the flow rate enhancement. Our results suggest that this simultaneous enhancement in transport and mixing is due to an enhancement in shear flow. As the flow above the cilia increases, the shear rate in the fluid increases and this shear enhances stretching, which is an essential ingredient for mixing. Estimates of the mixing time scale indicate that, compared to diffusion, the mixing due to the cilia beat may be significant and sometimes dominates chemical diffusion.
Sharp transition between coalescence and non-coalescence of sessile drops
Authors: Karpitschka Stefan , Riegler Hans 
Published: March 2014

AbstractUnexpectedly, under certain conditions, sessile drops from different but completely miscible liquids do not always coalesce instantaneously upon contact: the drop bodies remain separated in a temporary state of non-coalescence, connected through a thin liquid bridge. Here we investigate the transition between the states of instantaneous coalescence and temporary non-coalescence. Experiments reveal that it is barely influenced by viscosities and absolute surface tensions. The main system control parameters for the transition are the arithmetic means of the three-phase angles, $\overline{\Theta }_{a}$, and the surface tension differences $\Delta \gamma $ between the two liquids. These relevant parameters can be combined into a single system parameter, a specific Marangoni number $\widetilde{M}=3\Delta \gamma /(2\overline{\gamma }\overline{\Theta }_{a}^2)$. This $\widetilde{M}$ universally characterizes the coalescence transition behaviour as a function of both the physicochemical liquid properties and the shape of the liquid body in the contact region. The transition occurs at a certain threshold value $\widetilde{M}_t$ and is sharp within the experimental resolution. The experimentally observed threshold value of $\widetilde{M}_t\approx 2$ agrees quantitatively with values obtained by simulations assuming realistic material parameters. The simulations indicate that the absolute value of $\widetilde{M}_t$ very weakly depends on the molecular diffusivity.
Does the Location of Directors Matter? Information Acquisition and Board Decisions
Authors: Alam Zinat S. , Chen Mark A. , Ciccotello Conrad S. , Ryan Harley E. 
Published: March 2014

AbstractUsing data on over 4,000 individual residential addresses, we find that geographic distance between directors and corporate headquarters is related to information acquisition and board decisions. The fraction of a board’s unaffiliated directors who live near headquarters is higher when information-gathering needs are greater. When the fraction of unaffiliated directors living near headquarters is lower, nonroutine chief executive officer (CEO) turnover is more sensitive to stock performance. Also, the level, intensity, and sensitivity of CEO equity-based pay increase with board distance. Overall, our results suggest that geographic location is an important dimension of board structure that influences directors’ costs of gathering information.
Optimization-based dynamic 3D human running prediction: effects of foot location and orientation
Authors: Chung Hyun-Joon , Xiang Yujiang , Arora Jasbir S. , Abdel-Malek Karim 
Published: March 2014

SUMMARYThis paper presents optimization-based dynamic three-dimensional (3D) human running prediction. A predictive dynamics method is used to formulate the running problem, and normal running is formulated as a symmetric and cyclic motion. In addition, a slow jog along curved paths has been formulated. It is a non-symmetric running motion, so a stride formulation has been used. The dynamic effort and impulse are used as the performance measure, and the upper body yawing moment is also included in the performance measure. The joint angle profiles and joint torque profiles are calculated for the full-body human model, and the ground reaction force is determined. The effects of foot location and orientation on the running motion prediction are simulated and studied. Simulation results from this methodology show good correlation with experimental data obtained from human subjects.
Sediment and solute discharge into the Tay Estuary from the river system
Authors: Al-Jabbari M. H. , McManus J. , Al-Ansari N. A. 
Published: March 2014

SynopsisThe River Tay, which drains a dominantly metamorphic catchment, has the largest freshwater discharge of any British river. Direct methods of determining the solute, suspension and bed loads at six gauging stations have enabled the river transport to be assessed at 375,000 and 997,000 tonnes annually for dry and average wet years respectively. Added to estimates of loads from the Earn and Isla rivers the load entering the head of the Tay Estuary varies from 646,000 tonnes to 1,648,000 tonnes annually. This corresponds to total losses of 100 t/km2/year to 255 t/km2 year, which equates with an average lowering of the basin surface by 4–5 cm to 11.6 cm per thousand years of dry and average conditions respectively.
Enrichment, enumeration and characterisation of nitrate-reducing bacteria present in sediments of the River Tay Estuary
Authors: Dunn G. M. , Wardell J. N. , Herbert R. A. , Brown C. M. 
Published: March 2014

SynopsisSediments from the River Tay contained higher concentrations of ammonia than nitrate throughout an 18 month sampling cycle. Sediments from Kingoodie Bay and from the North Sea off the Tay Estuary produced nitrite and ammonia when incubated in the presence of nitrate.The nitrate-reducing bacteria present in Kingoodie Bay sediments were Aeromonasj Vibrio organisms with smaller numbers of enterobacteria and pseudomonads and even smaller numbers of acinetobacters. Continuous culture enrichments of sediments showed that in media containing no added NaCl, acinetobacters predominated anaerobically in the presence of nitrate and acetate while enterobacteria predominated in the presence of nitrate and glycerol. With 0.2M NaCl added to media enterobacteria were predominant, irrespective of carbon source, while with 0.4M NaCl addition pseudomonads predominated in acetate and enterobacteria in glycerol media.These results indicate that, at the salinities observed in the Tay Estuary at Kingoodie Bay, fermentative bacteria are most likely to be active in nitrate reduction.
The history and spread of bracken in Britain
Authors: Page C. N. 
Published: March 2014

SynopsisBracken, Pleridium aquilinum, has long been present in Britain as part of the native flora. Before the arrival of man, Britain was a wooded and forested country, and in this vegetation bracken was an open woodland and forest margin species, which played only a relatively minor vegetational role. Its biology is such, however, that this plant is able to spread rapidly in response to removal of the forest canopy, developing into colonies which are much more ecologically aggressive and dominating than was the original habit of the plant when undisturbed.In open conditions, bracken also has a far greater spore output than in more shaded ones. It is able to establish anew from spores only in relatively virgin soil conditions, particularly those produced by burning of other vegetation. Burning also benefits established bracken by removal of its competitors, whilst heavy and selective grazing by sheep also slowly reduces the natural vegetation competition in favour of bracken's further spread.The history of the spread of bracken in Britain from palynological and historical evidence is reviewed in the light of this biology and, in particular, its spread as man has progressively removed the forest canopy,introduced steady heavy grazing pressure, and has burned, and continues to burn, vegetation.
The carcinogenic, mutagenic and teratogenic toxicity of bracken
Authors: Evans I. Antice , Prorok J. H. , Cole R. C. , Al-Salmani M. H. , Al-Samarrai A. M. H. , Patel M. C. , Smith R. M. M. 
Published: March 2014

SynopsisInformation concerning the carcinogenicity of bracken fern (Pteridium aquilinum) in different species and organs is reviewed. Various methods used in attempts to identify the plant components responsible are described and the results evaluated. Reference is made to recent and current research in this field (University College of North Wales, Bangor) and includes mutagenic and sterility studies, and the introduction of teratogenic screening by injection of Japanese quail eggs. The many problems still challenging bracken workers are indicated, and a final section deals with the potential hazard to human health in an attempt to link experimental work with epidemiological surveys of human cancer incidence. One important result of the study of bracken carcinogenicity is that active components, previously thought to be harmless, can be found in a wide variety of regular dietary items.
A historical review of marine fish disease studies with special reference to Scotland
Authors: Roberts Ronald J. 
Published: March 2014

SynopsisThe study of marine fish diseases has been directly related in its development to the significance of the fisheries or latterly aquaculture systems involved with epizootics. In this respect, Scotland has played a central role because of the importance of specific diseases of salmon which have been especially prevalent in Scotland, and the advanced state of its basic veterinary and medical expertise. This has been particularly important in the past, when very little information was available and extrapolation from higher animal studies was the only relevant approach.
Monoclonal antibodies in relation to viruses and their possible clinical application
Authors: Gardner P. S. 
Published: March 2014

SynopsisCurrent research into viral monoclonal antibodies is reviewed in the light of their use or potential use as diagnostic reagents. Special attention is paid to influenza, the adenovirus group, herpes virus hominis types 1 and 2, rota viruses, hepatitis and cytomegalovirus. Although monoclonal antibodies have many advantages, particularly as regards specificity, purity, reproducibility, homogeneity and availability in unlimited supplies, certain problems are inherent in their very nature. Their preciseness may in fact be a hindrance to their use in diagnosis necessitating their recombination in pools and the quality assessment of their reactions with their homologous 'wild" types presents large logistic problems. There is no doubt that a powerful new serological tool has become available but their large-scale diagnostic use may be a little premature.
Variation in, and reproductive capacity of, Betula pendula and B. pubescens
Authors: Pelham J. , Kinnaird J. W. , Gardiner A. S. , Last F. T. 
Published: March 2014

SynopsisWhile B. pendula can be distingushed from B. pubescens by its diploid number of chromosomes, 28 compared with 56, separation by morphology depends upon a blend of variable characteristics, including leaf hairiness, occurrence of warts on branches, roughness of bark, pendulous habit and, most consistently, leaf shape.Individuals of B. pendula, like those of B. pubescens, are mostly self-incompatible. The dates of flowering of individuals within a population of trees may differ markedly. However, female flowers usually mature sooner than male flowers on the same tree. The pollen of Betula spp. can be wind-dispersed considerable distances. Seed production varies greatly from year to year. Within a seedlot, the onset of germination may differ by as much as 7 days.When side by side at latitude 56°N, trees from seed collected at southerly sites (lat. 50°N) in the natural ranges of B. pendula and B. pubescens grew taller than those from northerly (lat. 69°N) locations. However, when compared at latitude 69°N, the more northerly collections were the more vigorous. The seasonal onset of growth of different B. pubescens seedlings depended upon their origins. Seedlings from latitude 56°N commenced growth when days were 14h long; those from 63° and 70°N started when days were 16 and 20 h long respectively. Whereas northerly collections ceased growth when daytime temperatures dropped below 9°C, southerly collections continued to grow. The stem extension of B. pubescens seedlings grown from seeds collected at different altitudes (in the range of 200–1000m) was inversely related to the altitude of collection when compared at the same low altitude.Within a population, some B. pubescens seedlings grew significantly more than others when supplied with small amounts of nutrients, the differences disappearing when amounts of nutrients were increased. In Britain, B. pendula was usually more severely attacked by the rust fungus, Melampsoridium betulinum, than B. pubescens whereas in southern Sweden, B. pubescens has been reported as the more severely attacked. At both locations, there were conspicuous within-species differences. More fruitbodies of sheathing mycorrhizal fungi were produced in association with southerly, than with northerly, collections of both B. pubescens and B. pendula—384 compared with nil fruitbodies per tree, 4 years after planting.
Betula nana L., a note on its status in the United Kingdom
Authors: Aston D. 
Published: March 2014

SynopsisBetula nana L., the dwarf birch, is shrub-like in habit. Today it has a relict distribution in the north of Britain. In the Early Post Glacial period, it was widespread throughout Britain. This paper reviews the present understanding of the species in our flora and describes aspects of its morphology, palaeoecology, current distribution, habitat and hybridizaton with the arborescent birches.
Mycorrhizal fungi of Betula spp.: factors affecting their occurrence
Authors: Mason P. A. , Wilson J. , Last F. T. 
Published: March 2014

SynopsisThe production of fruitbodies of mycorrhizal fungi associated with Betula spp. in an experimental site was observed to occur in a pattern ordered in time and space. Certain species of Inocybe, Hebeloma and Laccaria and Thelephora terrestris appeared in the first five years after planting: they were followed by species of Leccinum, Cortinarius and Russula. Usually more fungi were associated with B. pendula than with B. pubescens. More toadstools of Laccaria tortilis developed in association with one clone of B. pubescens than with another which favoured instead the development of Inocybe petiginosa.The idea of a fungal succession is supported by below-ground observation of mycorrhizas. Early- and late-stage fungi formed mycorrhizas on seedlings growing in sterile conditions whether inoculated with mycelia or spores. However, only early-stage fungi formed mycorrhizas in unsterile conditions.The concept of succession is based on observations made when treeless sites were planted with Betula spp. However, experimental planting of seedlings into soil with intact roots of older trees with mycorrhizas of Lactarius pubescens resulted in mycorrhizas on the seedlings: but no mycorrhizas formed if the roots of the older tree had been severed. This suggests that the pattern or sequence of mycorrhizal fungi associated with seedlings regenerating within natural stands is likely to differ from that associated with Betula spp. colonizing previously treeless sites.
Insects associated with birch
Authors: Shaw M. R. 
Published: March 2014

SynopsisThe entomology of birch in Britain (and to a lesser extent in Fennoscandia) is reviewed in broad ecological terms. In particular, the size of the associated fauna, the kinds of geographical distribution patterns seen for birch insects in Britain, birch defoliators, and the conservation needs of insects associated with birch in Scotland are considered. A closing section briefly outlines additional literature on the ecology of birch insects.
Genetics of plant-microbe nitrogen-fixing symbiosis
Authors: Machray G. C. , Stewart W. D. P. 
Published: March 2014

SynopsisA wide variety of plant-microbe nitrogen-fixing symbioses which include cyanobacteria as the nitrogenfixing partner exist. While some information has been gathered on the biochemical changes in the cyanobacterium upon entering into symbiosis, very little is known about the accompanying changes at the genetic level. Much of our present knowledge of the organisation and control of expression of nitrogenfixation (nif) genes is derived from studies of the free-living diazotrophKlebsiella pneumoniae. This organism thus provides a model system and source of experimental material for the genetic analysis of symbiotic nitrogen fixation. We describe the use of clonedK. pneumoniaegenes for nitrogen fixation and its regulation in the genetic analysis' of nitrogen fixation in cyanobacteria which can enter into symbiosis with plants. These studies reveal some dissimilarities in the organisation ofnifgenes and raise questions as to the genetic control of nitrogen fixation in symbiosis.
Lichens and plant nutrition
Authors: Millbank J. W. 
Published: March 2014

SynopsisThe part played by lichens in the nitrogen economy of natural ecosystems is reviewed. The ability of some lichens to fix nitrogen and the consequent likelihood of an enhanced contribution is discussed, leading to the appreciation that release of nitrogen compounds from their thalli is a frequent characteristic of their growth and development, and of some nutritional benefit to associated plants.Data on the contribution by the normal processes of growth, death and decay, to the combined nitrogen supply of those specialised habitats where lichens predominate or are frequent, are given. Such habitats are arctic and subarctic forest and tundra, and the Douglas fir forests of northwest U.S.A. The methods used for the estimation of the contribution of the lichens are outlined and details are given of recent and current studies of nitrogen movements by direct leaching during normal growth of nitrogen-fixing terricolous lichens in Finland and southwest Scotland. The latter study uses a laboratory apparatus to simulate field conditions in order to permit the use of atmospheres enriched with the heavy isotope of nitrogen, 15N.