Showing papers by "University of Leeds published in 2001"
TL;DR: A quantitative integration and review of research on the Theory of Planned Behaviour and the subjective norm, which found that intentions and self-predictions were better predictors of behaviour than attitude, subjective norm and PBC.
Abstract: The Theory of Planned Behaviour (TPB) has received considerable attention in the literature. The present study is a quantitative integration and review of that research. From a database of 185 independent studies published up to the end of 1997, the TPB accounted for 27% and 39% of the variance in behaviour and intention, respectively. The perceived behavioural control (PBC) construct accounted for significant amounts of variance in intention and behaviour, independent of theory of reasoned action variables. When behaviour measures were self-reports, the TPB accounted for 11% more of the variance in behaviour than when behaviour measures were objective or observed (R2s = .31 and .21, respectively). Attitude, subjective norm and PBC account for significantly more of the variance in individuals' desires than intentions or self-predictions, but intentions and self-predictions were better predictors of behaviour. The subjective norm construct is generally found to be a weak predictor of intentions. This is partly attributable to a combination of poor measurement and the need for expansion of the normative component. The discussion focuses on ways in which current TPB research can be taken forward in the light of the present review.
8,889 citations
TL;DR: Changing the use of tetracyclines in human and animal health as well as in food production is needed if this class of broad-spectrum antimicrobials through the present century is to continue to be used.
Abstract: Tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiae, mycoplasmas, rickettsiae, and protozoan parasites. They are inexpensive antibiotics, which have been used extensively in the prophlylaxis and therapy of human and animal infections and also at subtherapeutic levels in animal feed as growth promoters. The first tetracycline-resistant bacterium, Shigella dysenteriae, was isolated in 1953. Tetracycline resistance now occurs in an increasing number of pathogenic, opportunistic, and commensal bacteria. The presence of tetracycline-resistant pathogens limits the use of these agents in treatment of disease. Tetracycline resistance is often due to the acquisition of new genes, which code for energy-dependent efflux of tetracyclines or for a protein that protects bacterial ribosomes from the action of tetracyclines. Many of these genes are associated with mobile plasmids or transposons and can be distinguished from each other using molecular methods including DNA-DNA hybridization with oligonucleotide probes and DNA sequencing. A limited number of bacteria acquire resistance by mutations, which alter the permeability of the outer membrane porins and/or lipopolysaccharides in the outer membrane, change the regulation of innate efflux systems, or alter the 16S rRNA. New tetracycline derivatives are being examined, although their role in treatment is not clear. Changing the use of tetracyclines in human and animal health as well as in food production is needed if we are to continue to use this class of broad-spectrum antimicrobials through the present century.
3,647 citations
Australian National University1, University of Oxford2, University of Nottingham3, University of St Andrews4, Durham University5, Liverpool John Moores University6, University of New South Wales7, University of Cambridge8, California Institute of Technology9, Johns Hopkins University10, University of Leeds11, University of Edinburgh12
TL;DR: The 2dF Galaxy Redshift Survey (2dFGRS) as mentioned in this paper uses the 2DF multifibre spectrograph on the Anglo-Australian Telescope, which is capable of observing 400 objects simultaneously over a 2° diameter field.
Abstract: The 2dF Galaxy Redshift Survey (2dFGRS) is designed to measure redshifts for approximately 250 000 galaxies. This paper describes the survey design, the spectroscopic observations, the redshift measurements and the survey data base. The 2dFGRS uses the 2dF multifibre spectrograph on the Anglo-Australian Telescope, which is capable of observing 400 objects simultaneously over a 2° diameter field. The source catalogue for the survey is a revised and extended version of the APM galaxy catalogue, and the targets are galaxies with extinction-corrected magnitudes brighter than b J = 19.45. The main survey regions are two declination strips, one in the southern Galactic hemisphere spanning 80° × 15° around the SGP, and the other in the northern Galactic hemisphere spanning 75° × 10° along the celestial equator; in addition, there are 99 fields spread over the southern Galactic cap. The survey covers 2000 deg 2 and has a median depth of z = 0.11. Adaptive tiling is used to give a highly uniform sampling rate of 93 per cent over the whole survey region. Redshifts are measured from spectra covering 3600-8000 A at a two-pixel resolution of 9.0 A and a median S/N of 13 pixel - 1 . All redshift identifications are visually checked and assigned a quality parameter Q in the range 1-5; Q ≥ 3 redshifts are 98.4 per cent reliable and have an rms uncertainty of 85 km s - 1 . The overall redshift completeness for Q ≥ 3 redshifts is 91.8 per cent, but this varies with magnitude from 99 per cent for the brightest galaxies to 90 per cent for objects at the survey limit. The 2dFGRS data base is available on the World Wide Web at http://www. mso.anu.edu.au/2dFGRS.
2,296 citations
Book•
27 Feb 2001TL;DR: The history of mathematics can be surveyed from many dierent perspectives, such as those that try to shed light on the history of particular theorems and on the people who created them as mentioned in this paper.
Abstract: Articles on the history of mathematics can be written from many dierent perspectives. Some aim to survey a more or less wide landscape, and require the observer to watch from afar as theories develop and movements are born or become obsolete. At the other extreme, there are those that try to shed light on the history of particular theorems and on the people who created them. This article belongs to this second category. It is an attempt to explain Goldie’s theorems on quotient rings in the context of the life and times of the man who discovered them. 1. Fractions Fractions are at least as old as civilisation. The Egyptian scribes of 3,000 years ago were very skilful in their manipulation as attested by many ancient papyri. To the Egyptians and Mesopotamians, fractions were just tools to find the correct answer to practical problems in land surveying and accounting. However, the situation changed dramatically in Ancient Greece. To the Greek philosophers, number meant positive integer, and 1 was ‘the unity’, and as such, had to be indivisible. So how could ‘half’ be a number, since ‘half the unity’ did not make sense? Possibly as a consequence of that, the Greek mathematicians thought of fractions in terms of ratios of integers, rather than numbers. After the demise of Greek civilisation, mathematicians reverted to the more prosaic view that fractions were numbers. Indeed, for the next thousand years everyone seemed happy to compute with all sorts of ‘numbers’ without worrying much about what a number was really supposed to be. It was the need for a sound foundation for the infinitesimal calculus that put mathematicians face to face with the nature of numbers. The movement began in the 18th century, but its first fruits were only reaped in the 19th century in the movement that became known as the arithmetization of analysis. In short, mathematicians felt quite sure that they knew their integers very well; so they thought that by constructing the real numbers in terms of positive integers they would place the latter in a sure foundation. The most extreme version of this credo \
2,117 citations
TL;DR: The dual forces of habitat modification and climate change are likely to cause specialists to decline, leaving biological communities with reduced numbers of species and dominated by mobile and widespread habitat generalists.
Abstract: Habitat degradation and climate change are thought to be altering the distributions and abundances of animals and plants throughout the world, but their combined impacts have not been assessed for any species assemblage1,2,3,4. Here we evaluated changes in the distribution sizes and abundances of 46 species of butterflies that approach their northern climatic range margins in Britain—where changes in climate and habitat are opposing forces. These insects might be expected to have responded positively to climate warming over the past 30 years, yet three-quarters of them declined: negative responses to habitat loss have outweighed positive responses to climate warming. Half of the species that were mobile and habitat generalists increased their distribution sites over this period (consistent with a climate explanation), whereas the other generalists and 89% of the habitat specialists declined in distribution size (consistent with habitat limitation). Changes in population abundances closely matched changes in distributions. The dual forces of habitat modification and climate change are likely to cause specialists to decline, leaving biological communities with reduced numbers of species and dominated by mobile and widespread habitat generalists.
1,273 citations
TL;DR: There is much inconsistency regarding emotional and cognitive care, although one relatively consistent finding is that physicians who adopt a warm, friendly, and reassuring manner are more effective than those who keep consultations formal and do not offer reassurance.
1,206 citations
TL;DR: In this paper, the authors compare the timing of mass extinctions with the formation age of large igneous provinces and reveal a close correspondence in five cases, but previous claims that all such provinces coincide with extinction events are unduly optimistic.
1,082 citations
TL;DR: It is argued that more detailed studies are needed, examining extinction rates and other sources of variation in species richness, to convincingly conclude speciation by sexual selection.
Abstract: The power of sexual selection to drive changes in mate recognition traits gives it the potential to be a potent force in speciation. Much of the evidence to support this possibility comes from comparative studies that examine differences in the number of species between clades that apparently differ in the intensity of sexual selection. We argue that more detailed studies are needed, examining extinction rates and other sources of variation in species richness. Typically, investigations of extant natural populations have been too indirect to convincingly conclude speciation by sexual selection. Recent empirical work, however, is beginning to take a more direct approach and rule out confounding variables.
1,077 citations
TL;DR: A generic statistical mechanical model is presented for the self-assembly of chiral rod-like units, such as β-sheet-forming peptides, into helical tapes, which with increasing concentration associate into twisted ribbons, fibrils, and fibers and sheds new light on the factors governing the structures and stability of pathological amyloid fibrs in vivo.
Abstract: A generic statistical mechanical model is presented for the self-assembly of chiral rod-like units, such as beta-sheet-forming peptides, into helical tapes, which with increasing concentration associate into twisted ribbons (double tapes), fibrils (twisted stacks of ribbons), and fibers (entwined fibrils). The finite fibril width and helicity is shown to stem from a competition between the free energy gain from attraction between ribbons and the penalty because of elastic distortion of the intrinsically twisted ribbons on incorporation into a growing fibril. Fibers are stabilized similarly. The behavior of two rationally designed 11-aa residue peptides, P(11)-I and P(11)-II, is illustrative of the proposed scheme. P(11)-I and P(11)-II are designed to adopt the beta-strand conformation and to self-assemble in one dimension to form antiparallel beta-sheet tapes, ribbons, fibrils, and fibers in well-defined solution conditions. The energetic parameters governing self-assembly have been estimated from the experimental data using the model. The 8-nm-wide fibrils consist of eight tapes, are extremely robust (scission energy approximately 200 k(B)T), and sufficiently rigid (persistence length l(fibril) approximately 20-70 microm) to form nematic solutions at peptide concentration c approximately 0.9 mM (volume fraction approximately 0.0009 vol/vol), which convert to self-supporting nematic gels at c > 4 mM. More generally, these observations provide a new insight into the generic self-assembling properties of beta-sheet-forming peptides and shed new light on the factors governing the structures and stability of pathological amyloid fibrils in vivo. The model also provides a prescription of routes to novel macromolecules based on a variety of self-assembling chiral units, and protocols for extraction of the associated energy changes.
969 citations
TL;DR: Current knowledge of biosynthetic enzymes, plant and microbial pectinases and the interactions of pECTin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development.
Abstract: Pectin is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan-I and rhamnogalacturonan-II) are thought to occur in all primary cell walls This review surveys what is known about the structure and function of these pectin domains The high degree of structural complexity and heterogeneity of the pectic matrix is produced both during biosynthesis in the endomembrane system and as a result of the action of an array of wall-based pectin-modifying enzymes Recent developments in analytical techniques and in the generation of anti-pectin probes have begun to place the structural complexity of pectin in cell biological and developmental contexts The in muro de-methyl-esterification of homogalacturonan by pectin methyl esterases is emerging as a key process for the local modulation of matrix properties Rhamnogalacturonan-I comprises a highly diverse population of spatially and developmentally regulated polymers, whereas rhamnogalacturonan-II appears to be a highly conserved and stable pectic domain Current knowledge of biosynthetic enzymes, plant and microbial pectinases and the interactions of pectin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development
967 citations
TL;DR: In vitro and in vivo data support the hypothesis that Thal may mediate its anti-MM effect, at least in part, by modulating NK cell number and function.
TL;DR: It is reported that two butterfly species have increased the variety of habitat types that they can colonize, and that two bush cricket species show increased fractions of longer-winged (dispersive) individuals in recently founded populations.
Abstract: Many animals are regarded as relatively sedentary and specialized in marginal parts of their geographical distributions. They are expected to be slow at colonizing new habitats. Despite this, the cool margins of many species' distributions have expanded rapidly in association with recent climate warming. We examined four insect species that have expanded their geographical ranges in Britain over the past 20 years. Here we report that two butterfly species have increased the variety of habitat types that they can colonize, and that two bush cricket species show increased fractions of longer-winged (dispersive) individuals in recently founded populations. Both ecological and evolutionary processes are probably responsible for these changes. Increased habitat breadth and dispersal tendencies have resulted in about 3- to 15-fold increases in expansion rates, allowing these insects to cross habitat disjunctions that would have represented major or complete barriers to dispersal before the expansions started. The emergence of dispersive phenotypes will increase the speed at which species invade new environments, and probably underlies the responses of many species to both past and future climate change.
University of Edinburgh1, Durham University2, Australian National University3, Liverpool John Moores University4, University of New South Wales5, University of Oxford6, University of St Andrews7, University of Cambridge8, California Institute of Technology9, Johns Hopkins University10, University of Leeds11, University of Nottingham12
TL;DR: In this paper, the authors presented the power spectrum of the galaxy distribution, calculated using a direct Fourier transform based technique and showed that within the k-space region 0.02 less than or similar to k less than and similar to 0.15 h Mpc(-1), the shape of this spectrum should be close to that of the linear density perturbations convolved with the window function of the survey.
Abstract: The 2dF Galaxy Redshift Survey has now measured in excess of 160 000 galaxy redshifts. This paper presents the power spectrum of the galaxy distribution, calculated using a direct Fourier transform based technique. We argue that, within the k-space region 0.02 less than or similar to k less than or similar to 0.15 h Mpc(-1), the shape of this spectrum should be close to that of the linear density perturbations convolved with the window function of the survey. This window function and its convolving effect on the power spectrum estimate are analysed in detail. By convolving model spectra, we are able to fit the power-spectrum data and provide a measure of the matter content of the Universe. Our results show that models containing baryon oscillations are mildly preferred over featureless power spectra. Analysis of the data yields 68 per cent confidence limits on the total matter density times the Hubble parameter Omega (m) h = 0.20 +/- 0.03, and the baryon fraction Omega (b)/Omega (m) = 0.15 +/- 0.07, assuming scale-invariant primordial fluctuations.
Imperial College London1, The Royal Marsden NHS Foundation Trust2, University of Western Australia3, Queensland University of Technology4, St. Vincent's Health System5, University of New South Wales6, Charles University in Prague7, University of Paris8, French Institute of Health and Medical Research9, Max Planck Society10, Ludwig Maximilian University of Munich11, National and Kapodistrian University of Athens12, University of Massachusetts Boston13, University of Hong Kong14, Royal College of Surgeons in Ireland15, University of Palermo16, Kanazawa University17, University of Fukui18, Tokyo Medical and Dental University19, Dokkyo Medical University20, Maastricht University21, Rikshospitalet–Radiumhospitalet22, Tan Tock Seng Hospital23, Autonomous University of Barcelona24, Linköping University25, University of Lausanne26, National Cheng Kung University27, University of Leeds28, University of Edinburgh29, University of Birmingham30, AstraZeneca31, University of Glasgow32, University of Manchester33, Cancer Research UK34, Yale University35, Brown University36, University of Pittsburgh37, Vanderbilt University38, Yeshiva University39, Military Medical Academy40
TL;DR: In this paper, the effect of the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer was investigated using a multivariate analysis.
Abstract: Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras incolorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P=0.004, HR 1.3) and overall survival (P=0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P=0.008, HR 1.5, overall survival P=0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P=0.46, HR 1.12, overall survival P=0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer. ⌐ 2001 Cancer Research Campaign.
University of Edinburgh1, Durham University2, Australian National University3, Liverpool John Moores University4, University of New South Wales5, University of Oxford6, University of St Andrews7, University of Cambridge8, California Institute of Technology9, Johns Hopkins University10, University of Leeds11, University of Nottingham12
TL;DR: A precise measurement of the clustering of superclusters of galaxies using the redshifts of more than 141,000 galaxies from the 2dF galaxy redshift survey is reported, which favours a low-density Universe with Ω ≈ 0.3.
Abstract: The large-scale structure in the distribution of galaxies is thought to arise from the gravitational instability of small fluctuations in the initial density field of the Universe. A key test of this hypothesis is that forming superclusters of galaxies should generate a systematic infall of other galaxies. This would be evident in the pattern of recessional velocities, causing an anisotropy in the inferred spatial clustering of galaxies. Here we report a precise measurement of this clustering, using the redshifts of more than 141,000 galaxies from the two-degree-field (2dF) galaxy redshift survey. We determine the parameter β = Ω ^(0.6)/b = 0.43 ± 0.07, where Ω is the total mass-density parameter of the Universe and b is a measure of the 'bias' of the luminous galaxies in the survey. (Bias is the difference between the clustering of visible galaxies and of the total mass, most of which is dark.) Combined with the anisotropy of the cosmic microwave background, our results favour a low-density Universe with Ω ≈ 0.3.
TL;DR: The results suggest that CD4(+)CD25(+) cells represent a population of regulatory T cells that arise during fetal life and may play a key role in the prevention of autoimmune diseases in humans.
TL;DR: In this article, the authors investigated the relationship between species richness (alpha diversity) and spatial turnover of species (beta diversity) in British avifauna and found that high richness locations have fewer species in common with neighbouring areas than low richness locations.
Abstract: Summary
1 Using data on the spatial distribution of the British avifauna, we address three basic questions about the spatial structure of assemblages: (i) Is there a relationship between species richness (alpha diversity) and spatial turnover of species (beta diversity)? (ii) Do high richness locations have fewer species in common with neighbouring areas than low richness locations?, and (iii) Are any such relationships contingent on spatial scale (resolution or quadrat area), and do they reflect the operation of a particular kind of species–area relationship (SAR)?
2 For all measures of spatial turnover, we found a negative relationship with species richness. This held across all scales, with the exception of turnover measured as βsim.
3 Higher richness areas were found to have more species in common with neighbouring areas.
4 The logarithmic SAR fitted better than the power SAR overall, and fitted significantly better in areas with low richness and high turnover.
5 Spatial patterns of both turnover and richness vary with scale. The finest scale richness pattern (10 km) and the coarse scale richness pattern (90 km) are statistically unrelated. The same is true of the turnover patterns.
6 With coarsening scale, locations of the most species-rich quadrats move north. This observed sensitivity of richness ‘hotspot’ location to spatial scale has implications for conservation biology, e.g. the location of a reserve selected on the basis of maximum richness may change considerably with reserve size or scale of analysis.
7 Average turnover measured using indices declined with coarsening scale, but the average number of species gained or lost between neighbouring quadrats was essentially scale invariant at 10–13 species, despite mean richness rising from 80 to 146 species (across an 81-fold area increase). We show that this kind of scale invariance is consistent with the logarithmic SAR.
TL;DR: It is demonstrated that, in addition to blockwise de-esterification, HG with a non-blockwise distribution of methyl esters is also an abundant feature of HG in primary plant cell walls, implications for understanding of both the action of pectin methyl esterases on matrix properties and mechanisms of intercellular adhesion and its loss in plants.
TL;DR: Computer simulation provides a general link between particle interactions, microstructure and rheological properties, and the role of competitive adsorption on emulsion properties can be derived from experiments on systems containing mixtures of milk proteins and small-molecule surfactants.
TL;DR: It is proposed that the inflammatory responses characteristic of spondyloarthropathies are triggered at these seemingly diverse sites, in genetically susceptible individuals, by a combination of anatomical factors which lead to higher levels of tissue microtrauma, and the deposition of microbes.
Abstract: The 2 major categories of idiopathic inflammatory arthritis are rheumatoid arthritis and the seronegative spondyloarthropathies. Whilst the synovium is the primary site of joint disease in the former, the primary site in the latter is less well defined. However, it has recently been proposed that enthesitis-associated changes in the spondyloarthropathies are primary and that all other joint manifestations are secondary. Nevertheless, some of the sites of disease localisation have not been adequately explained in terms of enthesitis. This article summarises current knowledge of the structure, function, blood supply, innervation, molecular composition and histopathology of the classic enthesis (i.e. the bony attachment of a tendon or ligament) and introduces the concept of ‘functional’ and articular ‘fibrocartilaginous’ entheses. The former are regions where tendons or ligaments wrap-around bony pulleys, but are not attached to them, and the latter are synovial joints that are lined by fibrocartilage rather than hyaline cartilage. We describe how these 3 types of entheses relate to other, and how all are prone to pathological changes in spondyloarthropathy. We propose that the inflammatory responses characteristic of spondyloarthropathies are triggered at these seemingly diverse sites, in genetically susceptible individuals, by a combination of anatomical factors which lead to higher levels of tissue microtrauma, and the deposition of microbes.
TL;DR: It is shown that the loss of this protein disrupts gamma frequency network oscillations in vitro but leaves high frequency rhythms, which may involve gap junctions between principal cells (Schmitz et al., 2001), unaffected.
Book•
23 Mar 2001TL;DR: Bygate, Skehan and Swain this paper investigated the effect of task repetition on the structure and control of oral language in a task-based language production of native and non-native speakers.
Abstract: 1 IntroductionMartin Bygate, Peter Skehan and Merrill Swain PART 1: TASKS AND LANGUAGE PROCESSING2 Effects of task repetition on the structure and control of oral languageMartin Bygate 3 Non-reciprocal tasks, comprehension and second language acquisitionRod Ellis 4 Rules and routines: A consideration of their role in the task-based language production of native and non-native speakersPauline Foster PART 2: STUDIES OF TASKS IN LANGUAGE CLASSROOMS5 Focus on form through collaborative dialogue: Exploring task effectsMerrill Swain and Sharon Lapkin 6 Guiding relationships between form and meaning during task performance: The role of the teacherVirginia Samuda 7 'A case of exercising': Effects of immediate task repetition on learners performanceTony Lynch and Joan Maclean PART 3: TASK-BASED APPROACHES TO TESTING8 Tasks and language performance assessmentPeter Skehan 9 Influences on performance in task-based oral assessmentsGillian Wigglesworth 10 Task-based assessments: Charactersitics and validity evidenceMicheline Chalhoub-Deville Afterword: Taking the Curriculum to TaskChristopher N Candlin
TL;DR: The consumption of figs by vertebrates is reviewed using data from the literature, unpublished accounts and new field data from Borneo and Hong Kong, supporting previous claims that Ficus is the most important plant genus for tropical frugivores.
Abstract: The consumption of figs (the fruit of Ficus spp.; Moraceae) by vertebrates is reviewed using data from the literature, unpublished accounts and new field data from Borneo and Hong Kong. Records of frugivory from over 75 countries are presented for 260 Ficus species (approximately 30% of described species). Explanations are presented for geographical and taxonomic gaps in the otherwise extensive literature. In addition to a small number of reptiles and fishes, 1274 bird and mammal species in 523 genera and 92 families are known to eat figs. In terms of the number of species and genera of fig-eaters and the number of fig species eaten we identify the avian families interacting most with Ficus to be Columbidae, Psittacidae, Pycnonotidae, Bucerotidae, Sturnidae and Lybiidae. Among mammals, the major fig-eating families are Pteropodidae, Cercopithecidae, Sciuridae, Phyllostomidae and Cebidae. We assess the role these and other frugivores play in Ficus seed dispersal and identify fig-specialists. In most, but not all, cases fig specialists provide effective seed dispersal services to the Ficus species on which they feed. The diversity of fig-eaters is explained with respect to fig design and nutrient content, phenology of fig ripening and the diversity of fig presentation. Whilst at a gross level there exists considerable overlap between birds, arboreal mammals and fruit bats with regard to the fig species they consume, closer analysis, based on evidence from across the tropics, suggests that discrete guilds of Ficus species differentially attract subsets of sympatric frugivore communities. This dispersal guild structure is determined by interspecific differences in fig design and presentation. Throughout our examination of the fig-frugivore interaction we consider phylogenetic factors and make comparisons between large-scale biogeographical regions. Our dataset supports previous claims that Ficus is the most important plant genus for tropical frugivores. We explore the concept of figs as keystone resources and suggest criteria for future investigations of their dietary importance. Finally, fully referenced lists of frugivores recorded at each Ficus species and of Ficus species in the diet of each frugivore are presented as online appendices. In situations where ecological information is incomplete or its retrieval is impractical, this valuable resource will assist conservationists in evaluating the role of figs or their frugivores in tropical forest sites.
TL;DR: Genetics Laboratory Investigations is a compilation of practical exercises that form a strong foundation in both classical genetics and more recent molecular genetic techniques for students at degree level and is accompanied by an Instructors Manual that includes hints, sources of materials, and answers to the many questions posed.
Abstract: As a recent convenor for a genetics MSc. course, I was amazed how many students graduating with a degree in genetics lack practical laboratory experience and possess limited knowledge of classical genetics. A good foundation of laboratory investigations is important to complement the theoretical information given in lectures and tutorials, but has been adversely aected by the need to keep costs down in many academic institutions in recent years. Genetics Ð Laboratory Investigations, the twelfth edition of a book that has enjoyed success since its initial publication in 1952, addresses this problem. It is a compilation of practical exercises that form a strong foundation in both classical genetics and more recent molecular genetic techniques for students at degree level. Many of the investigations are fairly low budget, while for those that include more expensive elements, cheaper options or sample data sets are given as an alternative. For example, the exercise on PCR gives a manual procedure using dishes of heated oil as an alternative where no PCR machine is available. I was pleasantly surprised how much I enjoyed reading this book! Although the investigations do form a logical progression through the book, it is clearly not designed to be read from cover to cover. However, for myself it was a short nostalgic trip through much of my own undergraduate degree in genetics, and I was left wondering whether earlier editions of this book had had any in ̄uence on the classical genetics practical classes I attended in the 1980s, such as using Drosophila stocks with curly wings and plum eye colour to locate an unknown mutant on a particular chromosome, or counting grey and black ascospores of Sordaria to investigate linkage and crossing-over during meiosis. This edition brings the content right up-to-date within a ®eld that is presently changing rapidly. The 26 exercises cover the range from classical Mendelian inheritance to molecular techniques such as PCR, RFLPs and DNA ®ngerprinting. Much of the human content is discussed in relation to the Human Genome Project where relevant, and also incorporated are new ideas, photographs, data sets and updated references and source material. All students' tastes are catered for with a wide variety of experimental organisms representing microbes, animals, plants and fungi. In particular the several humanbased investigations should appeal to most. The exercises on analysing ®ngerprint ridge numbers and patterns, and whether your urine smells foul after eating asparagus, are particularly intriguing. I was very impressed with the organisation and layout of this book. The text is written for degree-level students and is accompanied by an Instructors Manual that includes hints, sources of materials, and answers to the many questions posed. Each investigation is completely individual, independent and designed for use with no necessary modi®cations. All relevant references, notes and appendices are included in each exercise. Indeed the pages are perforated and hole-punched for easy removal and ®ling. Each exercise has a relevant introduction to the investigation, very clearly stated objectives, and all other information required for the exercise. Suitable data sheets for recording results, and relevant analyses are given, together with questions to test the understanding of the investigator. I was disappointed that the book makes so little use of online web resources. With so many students having both an interest in the Internet and also access to online computing facilities, I feel this is a weakness that should be addressed for the next edition. Another shortcoming is that the book is so clearly aimed at an American readership with all data sets provided based on American examples. Again, online resources could overcome this. I would certainly recommend the use of this book to anyone engaged in formulating or revising a degree-level genetics course.
TL;DR: Results suggest that the CORE-OM is a valid and reliable measure for multiple settings and is acceptable to users and clinicians as well as policy makers.
Abstract: To complement the evidence-based practice paradigm, the authors argued for a core outcome measure to provide practice-based evidence for the psychological therapies Utility requires instruments that are acceptable scientifically, as well as to service users, and a coordinated implementation of the measure at a national level The development of the Clinical Outcomes in Routine Evaluation-Outcome Measure (CORE-OM) is summarized Data are presented across 39 secondary-care services (n = 2,710) and within an intensively evaluated single service (n = 1,455) Results suggest that the CORE-OM is a valid and reliable measure for multiple settings and is acceptable to users and clinicians as well as policy makers Baseline data levels of patient presenting problem severity, including risk, are reported in addition to outcome benchmarks that use the concept of reliable and clinically significant change Basic quality improvement in outcomes for a single service is considered
TL;DR: It is shown that quercetin glucosides are not present in plasma of human subjects 1.5 h after consumption of onions (a rich source of flavonoid glucoside), and the existence of substitutions in the B and/or C ring of plasma quercets suggests that these conjugates will each have very different biological activities.
Abstract: The position of conjugation of the flavonoid quercetin dramatically affects biological activity in vitro, therefore it is important to determine the exact nature of the plasma metabolites. In the present study, we have used various methods (HPLC with diode array detection, LCMS, chemical and enzymic synthesis of authentic conjugates and specific enzymic hydrolysis) to show that quercetin glucosides are not present in plasma of human subjects 1.5 h after consumption of onions (a rich source of flavonoid glucosides). All four individuals had similar qualitative profiles of metabolites. The major circulating compounds in the plasma after 1.5 h are identified as quercetin-3-glucuronide, 3'-methylquercetin-3-glucuronide and quercetin-3'-sulfate. The existence of substitutions in the B and/or C ring of plasma quercetin metabolites suggests that these conjugates will each have very different biological activities.
TL;DR: In this article, the authors examined the distribution of strain and magmatism in the transitional active Main Ethiopian rift and found that magmatic segments accommodate >80% of the strain across the rift, indicating that border faults are no longer the locus of extension.
Abstract: Mechanical processes largely control the along-axis segmentation of continental rifts; however, asthenospheric processes strongly influence the along-axis segmentation of mid- ocean ridges. We examine the distribution of strain and magmatism in the transitional active Main Ethiopian rift. Magmatic construction, diking, and faulting during the past 1.6 m.y. have created ∼20-km-wide, ∼60-km-long magmatic segments with or without axial valleys. Magmatic segments are arranged en echelon within the ∼100-km-wide rift valley bounded by mid-Miocene border faults. Geodetic data show that magmatic segments accommodate >80% of the strain across the rift, indicating that border faults are no longer the locus of extension. Comparison with mid-ocean ridges suggests that magmatic segments, rather than detachment faults, mark the ocean-continent boundary in rifts with a ready magma supply. Magmatic margins, therefore, may contain detachments abandoned during continental breakup. The processes of localized dike intrusion with underplating would produce strips of mafic crust transitional to oceanic crust, but without coherent seafloor-spreading magnetic anomalies.
TL;DR: In this article, the authors developed a theory of "sticky reptation" to model the dynamics of entangled solutions of associating polymers with many stickers per chain, which predicts a very strong concentration dependence of viscosity in good agr...
Abstract: The process of making and breaking reversible bonds between associating groups (stickers) controls the dynamics of associating polymers. We develop a theory of “sticky reptation” to model the dynamics of entangled solutions of associating polymers with many stickers per chain. At a high degree of association, there are very few unassociated stickers. It is therefore very difficult for a sticker to find a new partner to associate with after breaking the bond with an old one. Typically a sticker returns to its old partner following an unsuccessful search for a new one, prolonging the effective lifetime of reversible bonds. In the sticky reptation model, the search for a new partner is restricted to a part of the tube confining the entangled chain. Another important effect is the increase of the fraction of the interchain associations at the expense of the intrachain ones with increasing polymer concentration. The sticky reptation model predicts a very strong concentration dependence of viscosity in good agr...
TL;DR: A paradigm shift away from using solvents in organic synthesis as solventless reactions can lead to improved outcomes, and more benign synthetic procedures, in for example aldol condensation reactions and oligomerisation reactions for the synthesis of cavitands.
TL;DR: Current knowledge of the Ca2+ -calmodulin messenger system in plants is summarized, suggestions for future areas of research are presented, and advances in functional genomics are presented.
Abstract: The complexity of Ca2+ patterns observed in eukaryotic cells, including plants, has led to the hypothesis that specific patterns of Ca2+ propagation, termed Ca2+ signatures, encode information and relay it to downstream elements (effectors) for translation into appropriate cellular responses. Ca2+ -binding proteins (sensors) play a key role in decoding Ca2+ signatures and transducing signals by activating specific targets and pathways. Calmodulin is a Ca2+ sensor known to modulate the activity of many mammalian proteins, whose targets in plants are now being actively characterized. Plants possess an interesting and rapidly growing list of calmodulin targets with a variety of cellular roles. Nevertheless, many targets appear to be unique to plants and remain uncharacterized, calling for a concerted effort to elucidate their functions. Moreover, the extended family of calmodulin-related proteins in plants consists of evolutionarily divergent members, mostly of unknown function, although some have recently been implicated in stress responses. It is hoped that advances in functional genomics, and the research tools it generates, will help to explain themultiplicity of calmodulin genes in plants, and to identify their downstream effectors. This review summarizes current knowledge of the Ca2+ -calmodulin messenger system in plants and presents suggestions for future areas of research. Contents I. Introduction 36 II. CaM isoforms and CaM-like proteins 37 III. CaM-target proteins 42 IV. CaM and nuclear functions 46 V. Regulation of ion transport 49 VI. CaM and plant responses to environmental stimuli 52 VII. Conclusions and future studies 58 Acknowledgements 59 References 59.