bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large-scale contribution to mean wall shear stress in high-Reynolds-number flat-plate boundary layers up to 13650
Authors: Deck Sébastien , Renard Nicolas , Laraufie Romain , Weiss Pierre-Élie 
Published: March 2014

AbstractA numerical investigation of the mean wall shear stress properties on a spatially developing turbulent boundary layer over a smooth flat plate was carried out by means of a zonal detached eddy simulation (ZDES) technique for the Reynolds number range $3060\leq Re_{\theta }\leq 13\, 650$. Some asymptotic trends of global parameters are suggested. Consistently with previous findings, the calculation confirms the occurrence of very large-scale motions approximately $5\delta $ to $6 \delta $ long which are meandering with a lateral amplitude of $0.3 \delta $ and which maintain a footprint in the near-wall region. It is shown that these large scales carry a significant amount of Reynolds shear stress and their influence on the skin friction, denoted $C_{f,2}$, is revisited through the FIK identity by Fukagata, Iwamoto & Kasagi (Phys. Fluids, vol. 14, 2002, p. L73). It is argued that $C_{f,2}$ is the relevant parameter to characterize the high-Reynolds-number turbulent skin friction since the term describing the spatial heterogeneity of the boundary layer also characterizes the total shear stress variations across the boundary layer. The behaviour of the latter term seems to follow some remarkable self-similarity trends towards high Reynolds numbers. A spectral analysis of the weighted Reynolds stress with respect to the distance to the wall and to the wavelength is provided for the first time to our knowledge and allows us to analyse the influence of the largest scales on the skin friction. It is shown that structures with a streamwise wavelength $\lambda _x >\delta $ contribute to more than $60\, \%$ of $C_{f,2}$, and that those larger than $\lambda _x >2\delta $ still represent approximately $45\, \%$ of $C_{f,2}$.
Three-dimensional flow structures in laminar falling liquid films
Authors: Dietze Georg F. , Rohlfs W. , Nährich K. , Kneer R. , Scheid B. 
Published: March 2014

AbstractFull numerical simulations of the Navier–Stokes equations for four cases of vertically falling liquid films with three-dimensional surface waves have been performed. Flow conditions are based on several previous experimental studies where the streamwise and spanwise wavelengths were imposed, which we exploit by simulating periodic wave segments. The considered flows are laminar but approach conditions at which intermittent wave-induced turbulence has been observed elsewhere. Working liquids range from water to silicone oil and cover a large interval of the Kapitza number ($\textit {Ka}=18\mbox{--}3923$), which relates capillary to viscous forces. Simulations were performed on a supercomputer, using a finite-volume code and the volume of fluid and continuum surface force methods to account for the multiphase nature of the flow. Our results show that surface waves, consisting of large horseshoe-shaped wave humps concentrating most of the liquid and preceded by capillary ripples on a thin residual film, segregate the flow field into two regions: an inertia-dominated one in the large humps, where the local Reynolds number is up to five times larger than its mean value, and a visco-capillary region, where capillary and/or viscous forces dominate. In the inertial region, an intricate structure of different-scale vortices arises, which is more complicated than film thickness variations there suggest. Conversely, the flow in the visco-capillary region of large-$\textit {Ka} $fluids is entirely governed by the local free-surface curvature through the action of capillary forces, which impose the pressure distribution in the liquid film. This results in flow separation zones underneath the capillary troughs and a spanwise cellular flow pattern in the region of capillary wave interference. In some cases, capillary waves bridge the large horseshoe humps in the spanwise direction, coupling the two aforementioned regions and leading the flow to oscillate between three- and two-dimensional wave patterns. This persists over long times, as we show by simulations with the low-dimensional model of Scheidet al. (J. Fluid Mech., vol. 562, 2006, pp. 183–222) after satisfactory comparison with our direct simulations at short times. The governing mechanism is connected to the bridging capillary waves, which drain liquid from the horseshoe humps, decreasing their amplitude and wave speed and causing them to retract in the streamwise direction. Overall, it is observed that spanwise flow structures (not accounted for in two-dimensional investigations) are particularly complex due to the absence of gravity in this direction.
Viscid–inviscid pseudo-resonance in streamwise corner flow
Authors: Schmidt Oliver T. , Rist Ulrich 
Published: March 2014

AbstractThe stability of streamwise corner flow is investigated by means of direct numerical simulation at subcritical Reynolds numbers. The flow is harmonically forced, and global modes are extracted through a spectral decomposition. Spatial amplification in the near-corner region is observed even though the flow is shown to be subcritical in terms of spatial linear theory. This apparent discrepancy is resolved by extending the local analysis to include non-modal effects. It is demonstrated that the amplification is a result of the interaction between two coexistent spatial transient growth processes that can be associated with different parts of the linear stability spectrum. A detailed investigation of the underlying mechanisms shows that the transient amplification behaviour is caused by pseudo-resonance between the inviscid corner mode, and different sets of viscous modes. By comparison with studies of other locally inflectional flows, it is found that viscid–inviscid pseudo-resonance might be a general phenomenon leading to selective noise amplification.
Pearling instability of a cylindrical vesicle
Authors: Boedec G. , Jaeger M. , Leonetti M. 
Published: March 2014

AbstractA cylindrical vesicle under tension can undergo a pearling instability, characterized by the growth of a sinusoidal perturbation which evolves towards a collection of quasi-spherical bulbs connected by thin tethers, like pearls on a necklace. This is reminiscent of the well-known Rayleigh–Plateau instability, where surface tension drives the amplification of sinusoidal perturbations of a cylinder of fluid. We calculate the growth rate of perturbations for a cylindrical vesicle under tension, considering the effect of both inner and outer fluids, with different viscosities. We show that this situation differs strongly from the classical Rayleigh–Plateau case in the sense that, first, the tension must be above a critical value for the instability to develop and, second, even in the strong tension limit, the surface preservation constraint imposed by the presence of the membrane leads to a different asymptotic behaviour. The results differ from previous studies on pearling due to the consideration of variations of tension, which are shown to enhance the pearling instability growth rate, and lower the wavenumber of the fastest growing mode.
CICERO'SPRO MILONEAND THE ‘DEMOSTHENIC’ STYLE:DE OPTIMO GENERE ORATORUM10
Authors: La Bua Giuseppe 
Published: March 2014

In a passage from the late rhetorical treatise generally known asDe optimo genere oratorum, Cicero defends his past forensic competence in the face of Atticist critique by praising hisPro Miloneas an example of grand style (9–10):quod qui ita faciet, ut, si cupiat uberior esse, non possit, habeatur sane orator, sed de minoribus; magno autem oratori etiam illo modo saepe dicendum est in tali genere causarum.(10)ita fit ut Demosthenes certe possit summisse dicere, elate Lysias fortasse non possit. sed si eodem modo putant, exercitu in foro et in omnibus templis, quae circum forum sunt, conlocato, dici pro Milone decuisse, ut si de re privata ad unum iudicem diceremus, vim eloquentiae sua facultate, non rei natura metiuntur.If anyone speaks in this manner without being able to use a fuller style if he wishes, he should be regarded as an orator, but a minor one. The great orator must often speak in that way in dealing with cases of such a kind. (10) In other words, Demosthenes could certainly speak calmly, but Lysias perhaps not with passion. But if they think that at the trial of Milo, when the army was stationed in the Forum and in all the temples round about, it was fitting to defend him in the same style that we would use in pleading a private case before a single judge, they measure the power of eloquence by their own limited ability, not by the nature of the art.
Apparent source level of free-ranging humpback dolphin,Sousa chinensis, in the South China Sea
Authors: Kimura Satoko , Akamatsu Tomonari , Fang Liang , Wang Zhitao , Wang Kexiong , Wang Ding , Yoda Ken 
Published: March 2014

The acoustic performance and behaviour of free-ranging cetaceans requires investigation under natural conditions to understand how wild animals use sound. This is also useful to develop quantitative evaluation techniques for passive acoustic monitoring. There have been limited studies on the acoustics of the Indo-Pacific humpback dolphin; nevertheless, this species is of particular concern because of the anthropogenic activity in the coastal habitats. In the present study, we used a four-hydrophone array to estimate the apparent source levels (ASLs) of biosonar sequences (click trains), of this species in San-Niang Bay, China. As the dolphins approached the array, 173 click trains were found to meet the criteria of on-axis sounds produced within 60 m of the equipment. In total, 121 unclipped click trains were used for the ASL estimation. The qualified click trains contained 36.3 ± 32.5 clicks, lasting for 1.5 ± 1.5 s, with average inter-click intervals (ICIs) of 51.2 ± 38.3 ms. Average ICIs showed a bimodal distribution, with a cut-off at 20 ms. Short-range click trains, with short ICIs of <20 ms on average, were characterized by smaller ASLs, relatively stable ICIs and a shorter click train duration. The mean back-calculated ASL for humpback dolphins with an approximately maximum body size of 2.5 m was 181.7 ± 7.0 dB re 1 μPa at a distance of 1.6–57.2 m. This value was comparable to that recorded for other dolphins of similar body size, although the ASL estimates obtained in this study might be conservative.
The ecology of Bathyporeia pilosa (Amphipoda: Haustoriidae) in the Tay Estuary. I. Factors influencing the distribution on Tayport and Tentsmuir beaches
Authors: Khayrallah N. H. , Jones A. M. 
Published: March 2014

SynopsisThe distribution of Bathyporeia pilosa is discussed in relation to variations in a number of physical and chemical characters of the sediment on eight transects. Relationships were found between density and median particle diameter, silt content, and water content of the sediment, but stability of the beach appeared to be the main parameter influencing B. pilosa distribution. Sediment preference experiments showed that sediments varied in attractiveness, medium and fine grade sands being preferred: coarse sands and muds were avoided as were sediments with a high silt and clay content. Attractiveness in laboratory conditions was not correlated with observed field densities in some cases, indicating that other parameters were important in determining the distribution. Studies of swimming behaviour demonstrated the importance of current speed during the pelagic phase and it is concluded that hydrological conditions may be as important as sedimentary characteristics in the determination of the distribution of this species.
Quantitative studies on the marine Phycomycetes between Fladenground and the mouth of the River Tay
Authors: Kumar S. Raghu 
Published: March 2014

SynopsisQuantitative studies on marine Phycomycetes (thraustochytrids) were carried out at 6 stations between the Fladenground area of the North Sea and the mouth of the River Tay, between September 1975 and September 1976. Five samplings were made of the surface water and the sediment during this period. The number of fungi/litre sea water or sediment increased with the proximity to the mouth of the river compared to the high seas. The fungal population exhibited a seasonal fluctuation, a high number occurring in September and an extremely low number occurring in March. The sediments revealed a very high number of propagules/litre (up to 73,000) compared to the water (up to 384).
Acute bracken poisoning in homogastric and ruminant animals
Authors: Evans W. Charles , Patel M. C. , Koohy Y. 
Published: March 2014

SynopsisThe toxicity of bracken fern (Pteridium aquilinum(L) Kuhn) is complicated because this plant elaborates more than one type of agent potentially harmful to livestock.When simple-stomached animals are fed a diet containing some green fronds or rhizomes for a few weeks, they develop anorexia and inco-ordination symptoms; this polyneuritic syndrome shows all the characteristics of thiamine deficiency. Thiamine therapy is effective in curing the animal provided it is administered at the onset of clinical symptoms.Bracken staggers in the horse and rhizome poisoning of pigs are diseases of this nature,i.e. an avitaminosis B1has been induced. The causative agent in the fern is a steam-labile enzyme, thiaminase I, which destroys thiamine in such a way that it is no longer active in animal nutrition.Acute cattle bracken poisoning occurs after frequent eating of the fern over a period of weeks.Haemorrhages and fever are the characteristic clinical symptoms, and the animal usually dies within a few days. The fundamental lesion is bone marrow aplasia resulting in a severe leucopenia and thrombocytopenia.Thiaminase I is not involved in this disease. Bracken contains an organic chemical(s) which poisons rapidly dividing cells in the bovine animal. Sheep are less sensitive to this toxic agent, although the condition has been described along with 'bright-blindness* in some parts of Britain (e.g. North York Moors).Purification of the active principle causing cattle bracken poisoning from green fronds and rhizomes is far advanced; these methods are described, along with calf toxicity tests on each fraction. Chemical investigations are also under way to determine the nature of the components.Whether the cattle factor, in small doses over an extended period of time (years), is also the agent causing tumours in livestock, is probable but not certain. Some bracken constituents shown to be carcinogenic in small animals, e.g. shikimic acid, quercetin or the tannin fraction, are not capable of producing acute cattle bracken poisoning; neither does safrole or 1-indanone.Some of the sesquiterpene glycosides—the 'pterosides' and/or their aglycones, the 'pterosins', of which over 30 have been identified in bracken—are likely candidates. On the other hand, the active principle(s) may be something quite different; the search continues.
Monoclonal antibodies in the diagnosis, detection and therapy of cancer
Authors: Baldwin R. W. 
Published: March 2014

SynopsisThe production of monoclonal antibodies specifying tumour associated antigens is illustrated by studies with a spontaneously arising rat mammary carcinoma (Sp4). Fusion of spleen cells from tumour-immune rats with mouse myeloma (P3NS1) yielded hybridomas secreting antibody reacting with a tumour specific antigen. These approaches have subsequently been used to produce monoclonal antibodies reacting with human osteogenic sarcoma, although in this case the antigens detected are tumour associated rather than tumour-specific.The diagnostic applications of these monoclonal antibodies have been explored particularly to evaluate whether radiolabelled preparations can be used for ‘imaging’ tumours. This approach has been validated with the human osteogenic sarcoma xenograft in tests showing that tumours can be detected by y-camera scanning following injection of 131I-labelled antibody when used in conjunction with blood pool labelling using 113MIn and a computerised subtraction technique.Monoclonal antibodies also have considerable potential for targetting drugs. These approaches are illustrated by studies using anti-rat mammary carcinoma Sp4 monoclonal antibody linked to adriamycin for therapy of subcutaneous tumour. In addition to drug conjugates, monoclonal antibodies are being used for targeting immunomodulating agents. This is illustrated by another series of studies in which the anti-human osteogenic sarcoma monoclonal antibody has been conjugated to human lymphoblastoid cell interferon to produce a reagent for activating host natural killer cells.
Ecological aspects of birch
Authors: Gimingham C. H. 
Published: March 2014

SynopsisThe respective ecological amplitudes of the two British tree species of Betula are known only imperfectly. B. pendula is better represented on drier, lighter soils and is more of a southern, eastern and lowland species than B. pubescens, which belongs rather to the wetter, colder conditions of north, west and upland Britain. The contribution of the two species to different types of woodland community is briefly reviewed in this paper, and consideration is given to the status of ‘pure’ birchwoods. In some cases, the latter may have been derived from other woodland types; in others, by invasion of heath or grassland. However, some relict birchwoods above the altitudinal limits of dominance by other trees, and in the extreme north and west of Scotland, may be ‘natural’ or ‘climax’ woods.Birches show a number of characteristics of ‘r-selected’ plants and hence tend to be trees of secondary or seral woodlands. Factors determining the capacity of birch species to colonize bare ground or vegetation such as heath and grassland, are reviewed, with special reference to a study of invasion of Calluna heath at Dinnet, Aberdeenshire. The importance of the development of gaps in the Calluna canopy, or alternatively of fire, in providing suitable sites for establishment, is emphasized.Changes in the ground vegetation following the establishment of birch stands are outlined, as well as the subsequent development of seral birchwoods. Attention is drawn to the fact that many upland birchwoods are becoming moribund, and to the effects of grazing and other influences in preventing regeneration. The possibility of reversing this trend is discussed.
Macrofungi of birchwoods
Authors: Watling Roy 
Published: March 2014

SynopsisThe meagre history of the study of the fungi of birchwoods in Britain is offered as an introduction to more recent studies in the British Isles and in continental Europe. Four categories of fungi (parasites, suspected mycorrhizals and lignicolous and humicolous saprophytes) are recognized and discussed. Examples of the most frequently found species-associations are given in relation to environmental factors.
Fungal pathogens of birch in Britain
Authors: Bennell Alan P. , Millar Colin S. 
Published: March 2014

SynopsisFungi reported as parasites ofBetulain Britain are reviewed. Pathogens colonizing the major host organs: roots, stems, branches twigs and bark, foliage, flowers fruit and seed, together with those attacking seedlings, are assessed in turn. Other species of fungi not yet known from Britain, but having potential importance as disease agents are also discussed. The major stem decay pathogens and the occurrence of leaf rust in Britain and its significance as a major nursery disease are examined in detail. The status of the fungal parasites on birches in woodland and plantations, in ornamental plantings and in the nursery is considered.
Evolution of nitrogen-fixing symbioses
Authors: Sprent J. I. , Raven J. A. 
Published: March 2014

SynopsisBecause of both the energy costs and the slowness of the reactions of the nitrogenase complex compared with those involving some form of combined nitrogen (oxidised or reduced), we argue that the evolution of nitrogen-fixing organisms required an environment which was very limited in combined nitrogen. This is thought to have occurred after phototrophy evolved, but before water was used as a hydrogen donor (and therefore oxygen was present in the atmosphere). After oxygenic photosynthesis evolved, the need for a high level of biological nitrogen-fixation remained, since abiotic inputs were insufficient to keep pace with the rapidly evolving biomass (flora and fauna). Symbiotic fixation probably first evolved in the form of casual associations between cyanobacteria and most other groups of plants. By inhabiting the sporophytic generation of evolving land plants (cycads in particular), protection against nitrogenase-inactivating oxygen and a more desiccating environment was achieved simultaneously.We envisage nodulated plants arising by the transfer ofnifgenes into tumour-forming bacteria. In the case of legumes, these would be ancestors of extant agrobacteria, which gain entry into their hostsviawounds. Co-evolution of symbionts from nitrogen-fixing tumours has taken several routes, leading to extant nodules differing in mode of infection, structure and physiology. Evolution towards optimisation of oxygen usage is continuing.Nitrogen-fixing symbiosis in animal systems is only advantageous in specialised ecological niches in which wood is the sole dietary intake. In the case of shipworms, the symbiosis has many of the advanced features associated with nitrogen fixing root nodules.
Symbiosis with endomycorrhizas and nitrogen-fixing organisms
Authors: Daft M. J. , Clelland D. M. , Gardner Isobel C. 
Published: March 2014

SynopsisInteractions amongst plants and different endophytes are prevalent in soils deficient in both nitrogen and phosphorus. Several systems are now recognised, combining infections by both fungi and prokaryotes. Symbiotic associations are ancient and reflect the requirements for the maximum uptake of nitrogen and phosphorus in plant nutrition.
The distilling industry
Authors: McBain C. S. 
Published: March 2014

SynopsisThe distilling industry in Scotland is a story of 1000 years of romantic history, technical ingenuity and triumph.Starting with the Celts in a ‘do-it-yourself’ form, through to the Age of Invention around 1786 and with the background of Joseph Black, James Watt and Robert Burns, all of whom were associated with distilling, the cottage industry became industrialised. Then came the development of grain whisky in 1830, as distinct from malt whisky, to be followed by blended whisky in the 1860s.The various methods of production are described and mention made of such developments as new barleys, new genetically-engineered yeasts, advanced methods of malted barley production and, eventually, high speed handling of the matured whisky into bottles for international marketing.Yet the process has not basically changed in hundreds of years, retaining its tradition and prestige. Scotch whisky is still the most popular spirit in the world, outside Russia and China, and has become a multi-billion pound investment with numerous scientific and technological achievements.