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Fast electron generation and transport in high-intensity laser–solid interactions induces X-ray emission and drives ion acceleration. Effective production of these sources hinges on an efficient laser absorption into the fast electron population and control of divergence as the beam propagates through the target. Nanowire targets can be employed to increase the laser absorption, but it is not yet clear how the fast electron beam properties are modified. Here we present novel measurements of the emittance of the exiting fast electron beam from irradiated solid planar and nanowire targets via a pepper-pot diagnostic. The measurements indicate a greater fast electron emittance is obtained from nanowire targets. Two-dimensional particle-in-cell simulations support this conclusion, revealing beam defocusing at the wire–substrate boundary, a higher fast electron temperature and transverse oscillatory motion around the wires.
This Element Paratext printed with new English plays has a lot to tell us about what playwrights were attempting to do and how audiences responded, thereby contributing substantially to our understanding of larger patterns of generic evolution across two centuries. The presence (or absence) of twelve elements needs to be systematically surveyed. (1) Attribution of authorship; (2) generic designation; (3) performance auspices; (4) government license authorizing publication; (5) dedication; (6) prefaces of various sorts; (7a-b-c) list of characters (three types); (8) actors' names (sometimes with descriptive characterizations-very helpful for deducing intended authorial interpretation); (9) location of action; (10) prologue and epilogue for first production. Surveying these results, we can see that much of the generic evolution traceable in the later seventeenth century gets undone during the eighteenth-a reversal largely attributable to the Licensing Act of 1737. This title is also available as Open Access on Cambridge Core.
Adaptive thermogenesis and reduced fat oxidative capacity may accompany weight loss, continuing in weight maintenance. The present study aimed (1) to determine whether weight-reduced and weight-loss relapsed women are at greater metabolic risk for weight gain compared with BMI-matched controls with no weight-loss history, and (2) to identify protective strategies that might attenuate weight loss-associated adaptive thermogenesis and support successful weight-loss maintenance. Four groups of women were recruited: reduced-overweight/obese (RED, n 15), controls (low-weight stable weight; LSW, n 19) BMI <27 kg/m2; relapsed-overweight/obese (REL, n 11), controls (overweight/obese stable weight; OSW, n 11) BMI >27 kg/m2. Body composition (bioelectrical impedance), 75 g oral glucose tolerance test, fasting and postprandial metabolic rate (MR) and substrate utilisation (RER) and physical activity (accelerometer (7 d)) were measured. Sociobehavioural questionnaires and 3 × 24 h diet recalls were completed. Fasting and postprandial MR, RER and total daily energy intake (TDEI) were not different between RED and REL v. controls (P > 0·05). RED consumed less carbohydrate (44·8 (sd 10·3) v. 53·4 (sd 10·0) % TDEI, P = 0·020), more protein (19·2 (sd 6·0) v. 15·6 (sd 4·2) % TDEI, P = 0·049) and increased physical activity, but behaviourally reported greater dietary restraint (P = 0·002) compared with controls. TDEI, macronutrient intake and physical activity were similar between OSW and REL. REL reported higher subjective fasting and lower postprandial ratings of prospective food consumption compared with OSW. Weight-reduced women had similar RMR (adjusted for fat-free mass) compared with controls with no weight-loss history. Increased physical activity, higher protein intake and greater lean muscle mass may have counteracted weight loss-associated metabolic compensation and highlights their importance in weight-maintenance programmes.
You all know those jolly words from “ Alice's Adventures through the Looking Glass,” and in a measure we are about to push our way through the melting mirror of hearsay to the strange world of wonderful facts, where boats fly, and men think nothing of the sort of ascent that blew the breath out of the poor White King when he received his first dusting in the air. We will talk, you and I, of shoes for aircraft—ships that fly and sealing wax that guards the secrets that have made the British seaplane the greatest example of its kind in all the wide world.
First of all you would like to find out, I know, how aircraft manage to fly at all.
You can find that out easily. Take a large box lid or other flat surface, hold it up vertically before you and run across the room with it.
Before opening my subject let me explicitly impress upon you that any opinions I may be found to have expressed in these notes are purely my own, and not necessarily shared by the Service to which I have the honour to belong, much as I owe them to its inspiration.
We set out to investigate whether Salmonella enterica could be recovered from various tissues of viable neonatal calves immediately following parturition. Eleven samples were aseptically collected from each of 20 calves and consisted of both left and right subiliac and prescapular lymph nodes (LN), mesenteric LN, spleen and liver, as well as intestinal tissue (including luminal contents) from the small intestine, caecum, spiral colon and rectum. In addition, a faecal sample was collected from 19 of the dams. Salmonella was recovered from at least one sample from 10 of the 20 neonates. Across all calves, Salmonella was recovered from 12·7% of all samples and from LN in particular, Salmonella was recovered from 10·0%, 5·0%, and 5·0% of subiliac, prescapular, and mesenteric LN, respectively. Within calves, Salmonella was recovered from 0% to 73% of samples and across tissues, estimates of Salmonella prevalence were greatest in the caecum (30%) but was never recovered from the right pre-scapular LN. These data provide evidence of vertical transmission from a dam to her fetus such that viable calves are born already infected and thereby not requiring faecal–oral exposure for transmission. This new knowledge ought to challenge – or at least add to – existing paradigms of Salmonella transmission dynamics within cattle herds.
The challenge for the next 50 years is to increase the productivity of major livestock species to address the food needs of the world, while at the same time minimizing the environmental impact. The present review presents an optimistic view of this challenge. The completion of genome sequences, and high-density analytical tools to map genetic markers, allows for whole-genome selection programmes based on linkage disequilibrium for a wide spectrum of traits, simultaneously. In turn, it will be possible to redefine genetic prediction based on allele sharing, rather than pedigree relationships and to make breeding value predictions early in the life of the peak sire. Selection will be applied to a much wider range of traits, including those that are directed towards environmental or adaptive outcomes. In parallel, reproductive technologies will continue to advance to allow acceleration of genetic selection, probably including recombination in vitro. Transgenesis and/or mutagenesis will be applied to introduce new genetic variation or desired phenotypes. Traditional livestock systems will continue to evolve towards more intensive integrated farming modes that control inputs and outputs to minimize the impact and improve efficiency. The challenges of the next 50 years can certainly be met, but only if governments reverse the long-term disinvestment in agricultural research.
Comparative physiology applies methods established in domestic animal science to a wider variety of species. This can lead to improved insight into evolutionary adaptations of domestic animals, by putting domestic species into a broader context. Examples include the variety of responses to seasonally fluctuating environments, different adaptations to heat and drought, and in particular adaptations to herbivory and various herbivore niches. Herbivores generally face the challenge that a high food intake compromises digestive efficiency (by reducing ingesta retention time and time available for selective feeding and for food comminution), and a variety of digestive strategies have evolved in response. Ruminants are very successful herbivores. They benefit from potential advantages of a forestomach without being constrained in their food intake as much as other foregut fermenters, because of their peculiar reticuloruminal sorting mechanism that retains food requiring further digestion but clears the forestomach of already digested material; the same mechanism also optimises food comminution. Wild ruminants vary widely in the degree to which their rumen contents ‘stratify’, with little stratification in ‘moose-type’ ruminants (which are mostly restricted to a browse niche) and a high degree of stratification into gas, particle and fluid layers in ‘cattle-type’ ruminants (which are more flexible as intermediate feeders and grazers). Yet all ruminants uniformly achieve efficient selective particle retention, suggesting that functions other than particle retention played an important role in the evolution of stratification-enhancing adaptations. One interesting emerging hypothesis is that the high fluid turnover observed in ‘cattle-type’ ruminants – which is a prerequisite for stratification – is an adaptation that not only leads to a shift of the sorting mechanism from the reticulum to the whole reticulo-rumen, but also optimises the harvest of microbial protein from the forestomach. Although potential benefits of this adaptation have not been quantified, the evidence for convergent evolution toward stratification suggests that they must be substantial. In modern production systems, the main way in which humans influence the efficiency of energy uptake is by manipulating diet quality. Selective breeding for conversion efficiency has resulted in notable differences between wild and domestic animals. With increased knowledge on the relevance of individual factors, that is fluid throughput through the reticulo-rumen, more specific selection parameters for breeding could be defined to increase productivity of domestic ruminants by continuing certain evolutionary trajectories.
This 2006 book examines the exciting discoveries in the study of marsupials of the last 20 years. These discoveries have led to significant developments in our understanding of this unique group of mammals. The impact of these developments have been such that marsupials are coming to be seen as model organisms in studies of life history evolution, ageing and senescence, sex determination and the development and regeneration of the nervous system. This volume brings together information scattered throughout the primary literature. Coverage includes evolutionary history and management strategies as well as all aspects of basic biology. A complete listing of known species and a comprehensive list of references make this a unique repository of information on this fascinating group of animals.
The morphology of independent plants of ‘Grasslands Ruanui’ perennial ryegrass (Lolium perenne L.) and three cultivars of cocksfoot (Dactylis glomerata L.) (‘Grasslands Apanui’, ‘Grasslands Kara’ and ‘Grasslands Wana’) in mixed pastures under intensive sheep grazing was studied at Palmerston North, New Zealand during 1991/92.
Both perennial ryegrass and cocksfoot exhibited a similar pattern of clonal growth and population structure. Distribution of plants among various orders of branching showed a relatively stable pattern through most of the year except in spring, when stem decay and plant fragmentation exceeded apical growth and regeneration, causing an increase in the proportion of small plants and a corresponding decrease of larger plants. This pattern was similar to that previously reported for white clover (Trifolium repens L.). Nevertheless, seasonal variation in plant structure (number of leaves, tillers and stems per plant) was small, but variation in organ size (DW or length) was greater. Stolon formation through elongation of internodes occurred throughout the year, but was associated primarily with flowering.
Grazing management caused no differences in plant structure between species or among the cocksfoot cultivars, but did affect the size of organs, and hence plants. Cocksfoot plants were 50–60% heavier than perennial ryegrass under rotational grazing. Under set stocking, only perennial ryegrass and Wana cocksfoot exhibited sufficient phenotypic plasticity to survive, both Kara and Apanui cocksfoot failed to persist. The only consistent difference between the species was greater flowering in perennial ryegrass than in cocksfoot, in both the proportion of plants flowering, and the number of flowering tillers per plant. Both species produced stolons throughout the year, although perennial ryegrass and Wana cocksfoot had a higher proportion of plants with stolons than Apanui and Kara cocksfoot. Length and DW of stolons per plant were similar in both species.
As there was little variation in plant structure and plant density, length of stolons per unit area tended to parallel seasonal changes in pasture tiller density. The role of grazing management in the survival of tillers and plants, and subsequent performance of grass species in pastures is discussed.
The King's Theatre, Haymarket, was destroyed by fire in June 1789. Shortly thereafter some wealthy and powerful patrons – notably the Prince of Wales (the future George IV), the Duke of Bedford and the Marquis of Salisbury – launched an ambitious scheme to build a fabulously expensive Royal Opera House in Leicester Square. The venture was designed to re-establish London as a major centre for Italian opera and ballet, to reform the wayward financial and artistic management of the King's Theatre and to give the capital city a grand opera house of modern design that would rival any in Europe. Because the royal patent promised for Leicester Square was blocked, the scheme had to be dropped, and the sponsors wound up establishing the ill-fated and short-lived Pantheon Opera instead – but that is another story. Our concern here is with the Leicester Square project which, though never realised, did set in motion many of the changes desired by its backers and helped to return London to the mainstream of opera.
To what degree does late seventeenth-century English opera contain politics? Some recent critics have assumed that political commentary conveyed by allegory is a pervasive feature of ‘Restoration’ masques and operas. Is this true? Quite a few political interpretations of particular works have been published but no one has systematically enquired to what extent allegory and/or ideology was presumed to be built into operas mounted in late seventeenth-century London. Theoretical statements of the time about opera are scant and contradictory, their authors disinclined to take up political issues. Some of the political content is glaringly obvious (the allegory in Dryde'ns and Grabu's Albion and Albanius); some of it is sharply disputed. How should we read a work like Dryden's and Purcell's King Arthur? Is it essentially a muddled adventure story? An expression of British nationalism rising above current politics? A piece of covert Jacobite propaganda?
The Pantheon Opera remains among the least known of the major theatrical ventures in eighteenth-century London. It came into being amidst the conspiracies that flourished after the King's Theatre, Haymarket, was destroyed by fire in June 1789. Conceived as a kind of English Court Opera, the Pantheon was backed at enormous expense by the Duke of Bedford and the Marquis of Salisbury. It struggled through the 1790–91 season, accumulating ruinous debts, and then on 14 January 1792 it too burned to the ground, just four nights into its second season.
Sporadic salmonellosis has been reported in mature lactating dairy cattle in the southwestern United States and is an intriguing problem in that Salmonella can be cultured from faecal samples of these cattle throughout the year. However, it is pathogenic only during late summer/early autumn and in certain years. We sampled apparently healthy (n=10) and diarrhoeic (n=10) cattle during an outbreak on a 2000 head dairy in 2003. The following year, monthly faecal (from the same 30 head), total mixed ration, water, and pen soil samples were collected for Salmonella culture. No serogroup, serotype, genetic, or antimicrobial susceptibility differences were observed in comparison of isolates from healthy and sick cattle. During year 2 of the study, Salmonella was routinely cultured (although highly variable from month to month) from the cattle and the environment, although no outbreak of salmonellosis was observed.