Showing papers by "University of Hertfordshire published in 2003"

The systems biology markup language (SBML): a medium for representation and exchange of biochemical network models.

Abstract: Motivation: Molecular biotechnology now makes it possible to build elaborate systems models, but the systems biology community needs information standards if models are to be shared, evaluated and developed cooperatively. Results: We summarize the Systems Biology Markup Language (SBML) Level 1, a free, open, XML-based format for representing biochemical reaction networks. SBML is a software-independent language for describing models common to research in many areas of computational biology, including cell signaling pathways, metabolic pathways, gene regulation, and others. ∗ To whom correspondence should be addressed. Availability: The specification of SBML Level 1 is freely available from http://www.sbml.org/.

A very energetic supernova associated with the |[gamma]|-ray burst of 29 March 2003

Abstract: Over the past five years evidence has mounted that long-duration (greater than 2s) gamma-ray bursts (GRBs), the most brilliant of all astronomical explosions, signal the collapse of massive stars in our Universe. This evidence, originally based on the probable association of one unusual GRB with a supernova, now includes the association of GRBs with regions of massive star-formation in distant galaxies, tantalizing evidence of supernova-like light-curve 'bumps' in the optical afterglows of several bursts, and lines of freshly synthesized elements in the spectra of a few X-ray afterglows. These observations support, but do not yet conclusively validate, models based upon the deaths of massive stars, presumably associated with core collapse. Here we report evidence for a very energetic supernova (a hypernova), temporally and spatially coincident with a GRB at redshift z=0.1685. The timing of the supernova indicates that it exploded within a few days of the GRB, strongly suggesting that core-collapse events can give rise to GRBs. Amongst the GRB central engine models proposed to-date, the properties of this supernova thus favour the collapsar model.

Population‐based study of antibody to the human polyomaviruses BKV and JCV and the simian polyomavirus SV40

Abstract: Molecular studies suggest that the simian polyomavirus SV40 is present in the human population, possibly introduced in contaminated polio vaccine. However, no recent seroepidemiological data exist in England on SV40 or on the two human polyomaviruses, BKV and JCV. A comparative age seroprevalence study was undertaken on 2,435 residual sera from 1991 by haemagglutination inhibition (HI) for BKV and JCV, and virus neutralisation for SV40. The overall rates of seropositivity for BKV and JCV were 81% and 35%, respectively, and each was significantly related to age (P < 0.001). BKV seroprevalence reached 91% at 5-9 years of age, but JCV seroprevalence reached only 50% by age 60-69 years. There was a highly significant association between BKV antibody titre and age (P < 0.001), titres decreasing linearly at a rate of 8.7% per 10 years (95% CI = 7.4-10% drop). Significantly more males than females had antibody to JCV (P = 0.013). In individuals under 40 years of age there was a significant negative association between the presence of antibody to BKV and JCV (P < 0.001). By contrast, the antibody prevalence to SV40 remained at 1.3-5% throughout all age groups and titres were low. There was a significant positive association between the presence of antibody to SV40 and antibody to both BKV (P < 0.001) and JCV (P = 0.009), and also to the geometric mean titre (GMT) of BKV antibody (P = 0.011). The results indicate that BKV and JCV are transmitted by different routes. There is no serological evidence that SV40 entered the human population during the past 80 years, and the possibility of cross-reaction with BKV or JCV antibody must be considered.

Functional amounts of dystrophin produced by skipping the mutated exon in the mdx dystrophic mouse.

Abstract: As a target for gene therapy, Duchenne muscular dystrophy (DMD) presents many obstacles but also an unparalleled prospect for correction by alternative splicing. The majority of mutations in the dystrophin gene occur in the region encoding the spectrin-like central rod domain, which is largely dispensable. Thus, splicing around mutations can generate a shortened but in-frame transcript, permitting translation of a partially functional dystrophin protein. We have tested this idea in vivo in the mdx dystrophic mouse (carrying a mutation in exon 23 of the dystrophin gene) by combining a potent transfection protocol with a 2-O-methylated phosphorothioated antisense oligoribonucleotide (2OMeAO) designed to promote skipping of the mutated exon*. The treated mice show persistent production of dystrophin at normal levels in large numbers of muscle fibers and show functional improvement of the treated muscle. Repeated administration enhances dystrophin expression without eliciting immune responses. Our data establishes the realistic practicality of an approach that is applicable, in principle, to a majority of cases of severe dystrophinopathy.

Emotional intelligence training and its implications for stress, health and performance

Abstract: This study builds on earlier work (Slaski & Cartwright, 2002), examining the role of Emotional Intelligence (EI) as a moderator in the stress process. A sample of UK managers (n = 60) were given training in emotional intelligence. Pre and post measures were taken relating to EI, stress and health and management performance. The study also incorporated a matched control group. It was found that training resulted in increased EI and improved health and well being. Copyright © 2003 John Wiley & Sons, Ltd.

An abscisic acid-sensitive checkpoint in lateral root development of Arabidopsis

Abstract: Lateral root (LR) formation displays considerable plasticity in response to developmental and environmental signals. The mechanism whereby plants incorporate diverse regulatory signals into the developmental programme of LRs remains to be elucidated. Current concepts of lateral root regulation focus on the role of auxin. In this study, we show that another plant hormone, abscisic acid (ABA), also plays a critical role in the regulation of this post-embryonic developmental event. In the presence of exogenous ABA, LR development is inhibited. This occurs at a specific developmental stage, i.e. immediately after the emergence of the LR primordium (LRP) from the parent root and prior to the activation of the LR meristem, and is reversible. Interestingly, this inhibition requires 10-fold less ABA than the inhibition of seed germination and is only slightly reduced in characterised abi mutants, suggesting that it may involve novel ABA signalling mechanisms. We also present several lines of evidence to support the conclusion that the ABA-induced lateral root inhibition is mediated by an auxin-independent pathway. First, the inhibition could not be rescued by either exogenous auxin application or elevated auxin synthesis. Secondly, a mutation in the ALF3 gene, which is believed to encode an important component in the auxin-dependent regulatory pathway for the post-emergence LR development, does not affect the sensitivity of LRs to ABA. Thirdly, ABA and the alf3-1 mutation do not act at the same developmental point. To summarise, these results demonstrate a novel ABA-sensitive, auxin-independent checkpoint for lateral root development in Arabidopsis at the post-emergence stage. In addition, we also present data indicating that regulation of this developmental checkpoint may require novel ABA signalling mechanisms and that ABA suppresses auxin response in the LRPs.

Radiative properties and direct radiative effect of Saharan dust measured by the C-130 aircraft during SHADE: 1. Solar spectrum

Abstract: [1] The physical and optical properties of Saharan dust aerosol measured by the Met Office C-130 during the Saharan Dust Experiment (SHADE) are presented. Additional radiation measurements enable the determination of the aerosol optical depth, taerl, and the direct radiative effect (DRE) of the mineral dust. The results suggest that the absorption by Saharan dust is significantly overestimated in the solar spectrum if standard refractive indices are used. Our measurements suggest an imaginary part of the refractive index of 0.0015i is appropriate at a wavelength l of 0.55 mm. Different methods for determining taerl=0.55 are presented, and the accuracy of each retrieval method is assessed. The value taerl=0.55 is estimated as 1.48 ± 0.05 during the period of heaviest dust loading, which is derived from an instantaneous DRE of approximately � 129 ± 5 Wm � 2 or an enhancement of the local planetary albedo over ocean of a factor of 2.7 ± 0.1. A comparison of the DRE derived from the C-130 instrumentation and from the Clouds and the Earth’s Radiant Energy System (CERES) instrument on the Tropical Rainfall Measuring Mission (TRMM) satellite is presented; the results generally showing agreement to within a factor of 1.2. The results suggest that Saharan dust aerosol exerts the largest local and global DRE of all aerosol species and should be considered explicitly in global radiation budget studies. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0360 Atmospheric Composition and Structure: Transmission and scattering of radiation; 1640 Global Change: Remote sensing; 3359 Meteorology and Atmospheric Dynamics: Radiative processes;

Entanglement of Indistinguishable Particles Shared between Two Parties

Abstract: Using an operational definition we quantify the entanglement, E(P), between two parties who share an arbitrary pure state of N indistinguishable particles. We show that E(P) |1>, where both modes are split between the two parties, has E(P)=1/2. We discuss how this relates to quantum correlations between particles, for both fermions and bosons.

The hidden persuaders: institutions and individuals in economic theory

Abstract: In his classic book The Hidden Persuaders, Vance Packard claimed that large corporations manipulated consumers, using advertising techniques. John Kenneth Galbraith and others have repeated a similar view. Against this, Gary Becker and George Stigler have claimed that advertising is essentially informative rather than manipulative. In contrast, it is argued here that both of these opposed accounts of human agency neglect the more subtle and undesigned processes by which institutions bear upon and mould individuals. This paper proposes a concept of ‘reconstitutive downward causation’ in which institutions act upon individual habits and dispositions. The mechanisms involved do not fall foul of past critiques of ‘holism’ or methodological collectivism. This argument involves a rehabilitation of the concept of habit in social science, with far-reaching implications.

One ring to encompass them all: a giant stellar structure that surrounds the Galaxy

Abstract: We present evidence that the curious stellar population found by the Sloan Digital Sky Survey in the Galactic anticentre direction extends to other distant fields that skirt the plane of the Milky Way. New data, taken with the Isaac Newton Telescope Wide Field Camera, show a similar population, narrowly aligned along the line of sight, but with a galactocentric distance that changes from similar to15 to similar to20 kpc (over similar to100degrees on the sky). Despite being narrowly concentrated along the line of sight, the structure is fairly extended vertically out of the plane of the disc, with a vertical scaleheight of 0.75 +/- 0.04 kpc. This finding suggests that the outer rim of the Galaxy ends in a low surface brightness stellar ring. Presently available data do not allow us to ascertain the origin of the structure. One possibility is that it is the wraith of a satellite galaxy devoured long ago by the Milky Way, although our favoured interpretation is that it is a perturbation of the disc, possibly the result of ancient warps. Assuming that the ring is smooth and axisymmetric, the total stellar mass in the structure may amount to similar to2 x 10(8) M. up to similar to10(9) M(.).

The mean physical and optical properties of regional haze dominated by biomass burning aerosol measured from the C-130 aircraft during SAFARI 2000

Abstract: Original article can be found at: http://www.agu.org/journals/jd/ Copyright American Geophysical Union DOI: 10.1029/2002JD002226 [Full text of this article is not available in the UHRA]

Learning as an activity of interdependent people

Abstract: This paper argues that to talk about organisations learning is to reify and anthropomorphise organisations. Instead of thinking of an organisation as if it were a thing or a person it is closer to experience to think of an organisation as the patterning of peoples' interactions with each other. This paper explores the assumptions that are being made when we talk about organisations or groups that learn, or about individuals learning in groups or organisations. It suggests an alternative to thinking in these ways, namely, that learning is an activity of interdependent people. If one takes the view an organisation is the organising activities of interdependent people, it leads to a particular perspective on learning. Much of the communicative and power relating activities of interdependent people take the form of continually iterated patterns of repetition in which meaning and power figurations have the quality of stability which we call identity. But because of the nonlinear iterative nature of human interaction there is always the potential for small differences to be amplified into transformative shifts in identity. Learning is then understood as the emerging shifts in the patterning of human communicative interaction and power relating. Learning is the activity of interdependent people and can only be understood in terms of self‐organising communicative interaction and power relating in which identities are potentially transformed. Individuals cannot learn in isolation and organisations can never learn.

Measuring emotional intelligence: Content, construct and criterion-related validity.

Abstract: Many authors claim there is a paucity of evidence for the validity of measures of emotional intelligence (EI). This paper summarises existing information on the reliability and validity of two measures of EI, the Dulewicz and Higgs EIQ and the Bar‐on EQ‐i. It also reports the results of a study on middle managers which investigated the degree to which these two EI instruments measure the same constructs: their concurrent/criterion‐related validity; and the relationship between EI and morale and stress at work. Correlations between the two instruments showed content and construct validity, with 16 out of the 20 hypothesised relationships between scales being significant. Correlations between various measures of morale and stress at work and EIQ demonstrated construct validity. Significant relationships were also found between EIQ and current job performance, thus providing further evidence of concurrent/criterion‐related validity.

Quality in higher education: from monitoring to management

Abstract: Concepts of accountable management in the public sector have ensured that issues relating to performance measurement have been high on the agenda of higher education institutions. Several quality initiatives are happening at the same time as universities are faced with diminishing financial support from public sources of finance. It has been suggested that higher education should look to private sector models of performance measurement in order to address important quality issues. In taking such models, the paper argues the importance of recognising that key performance indicators on their own can be dysfunctional unless they are grounded within the culture of a strategy‐focussed organisation. The paper then proposes the use of a balanced scorecard approach in order to reinforce the importance of managing rather than just monitoring performance. A balanced scorecard for a faculty of business and management is developed in order to illustrate the points being made.

Environment and harvest time affects the combustion qualities of Miscanthus genotypes

Abstract: Miscanthus spp. are high-yielding perennial C 4 grasses, native to Asia, that are being investigated in Europe as potential biofuels. Production of economically viable solid biofuel must combine high biomass yields with good combustion qualities. Good biomass combustion quality depends on minimizing moisture, ash, K, chloride, N, and S. To this end, field trials at five sites in Europe from Sweden to Portugal were planted with 15 different genotypes including M. x giganteus, M. sacchariflorus, M. sinensis, and newly bred M. sinensis hybrids. Yield and combustion quality at an autumn and a late winter/ early spring harvest were determined in the third year after planting when the stands had reached maturity. As expected, delaying the harvest by three to four months improved the combustion quality of all genotypes by reducing ash (from 40 to 25 g kg -1 dry matter), K (from 9 to 4 g kg -1 dry matter), chloride (from 4 to 1 g kg -1 dry matter), N (from 5 to 4 g kg -1 dry matter), and moisture (from 564 to 291 g kg -1 fresh matter). However, the delayed harvest also decreased mean biomass yields from 17 to 14 t ha -1 . There is a strong interaction among yield, quality, and site growing conditions. Results show that in northern regions of Europe, M. sinensis hybrids can be recommended for high yields (yielding up to 25 t ha -1 ), but M. sinensis (nonhybrid) genotypes have higher combustion qualities. In mid- and south Europe, M. × giganteus (yielding up to 38 t ha -1 ) or specific high-yielding M. sinensis hybrids (yielding up to 41 t ha -1 ) are more suitable for biofuel production.

Systems biology markup language: Level 2 and beyond

Abstract: The SBML (systems biology markup language) is a standard exchange format for computational models of biochemical networks. We continue developing SBML collaboratively with the modelling community to meet their evolving needs. The recently introduced SBML Level 2 includes several enhancements to the original Level 1, and features under development for SBML Level 3 include model composition, multistate chemical species and diagrams.

Effectiveness of different precipitated phosphates as phosphorus sources for plants

Abstract: Eleven precipitated phosphates were evaluated as sources of phosphorus (P) for plant growth by comparing their effectiveness with that of monocalcium phosphate, a source of water-soluble P that is generally considered to be fully plant available. The precipitated phosphates comprised struvites recovered from waste water discharges (mainly magnesium ammonium phosphate), laboratory synthesised struvites, a synthetic iron phosphate and a recovered calcium phosphate. Precipitating phosphates in these forms could be a way for removing P from waste water before it is discharged to rivers, so reducing the risk of eutrophication. Application to agricultural land would be one potential use for such phosphates. Evaluation was by pot experiments with a sandy loam soil and with a sandy clay loam soil using perennial ryegrass as the test crop. The soils differed in pH (6.6 and 7.1) and in Olsen P (28 and 11 mg L -1 ). Measured variables were grass dry-matter (DM) yield and grass P concentration which were used to calculate offtake of P in the harvested grass. DM yields of ryegrass and P offtakes given by the synthetic and recovered struvites were not significantly different statistically either between themselves or to MCP applied at the same rate. On this basis these struvites could be used to recycle P to similar soils and the effect of the P on crop yield should be similar to that of MCP

Robust creation of entanglement between ions in spatially separate cavities.

Abstract: We present a protocol that allows the generation of a maximally entangled state between individual atoms held in spatially separate cavities. Assuming perfect detectors and neglecting spontaneous emission from the atoms, the resulting idealized scheme is deterministic. Under more realistic conditions, when the atom-cavity interaction departs from the strong coupling regime, and considering imperfect detectors, we show that the scheme is robust against experimental inefficiencies and yields probabilistic entanglement of very high fidelity.

Ice Particle Interarrival Times Measured with a Fast FSSP

Abstract: Ice particle interarrival times have been measured with a fast forward scattering spectrometer probe (FSSP). The distribution of interarrival times is bimodal instead of the exponential distribution expected for a Poisson process. The interarrival time modes are located at ∼10−2 and ∼10−4 s. This equates to horizontal spacings on both the centimeter and meter scales. The characteristics of the interarrival times are well modeled by a Markov chain process that couples together two independent Poisson processes operating at different scales. The possibility that ice crystals shattering on the probe tip causes the bimodal interarrival times is explored and cannot be ruled out. If the observations are indicating real spacings of particles in clouds, then the observations show very localized (centimeter scale) concentrations of ∼100 s cm−3 embedded within an average concentration of typically ∼1 cm−3. If the localized high concentrations are produced by the ice crystals shattering, then the concentrat...

Employer travel plans, cycling and gender: will travel plan measures improve the outlook for cycling to work in the UK?

Abstract: Cycling is a ‘green’ alternative to commuting by car yet it makes up only a small percentage of journeys in the UK. Here we examine the commuter habits of three companies in Hertfordshire, UK. These provide contrasting case studies allowing examination of travel behaviour in relation to gender and employer travel plans. Women are known to commute shorter distances, yet are less likely to cycle. A variety of cultural and trip characteristics can account for this yet more detailed analysis reveals that some generalisations do not apply. Organisational initiatives to increase cycle commuting were perceived more positively by men than women and this suggests provision of cycling facilities in travel plans will not be effective for organisations employing a large proportion of women. However, this hides a subgroup of women who have access to a cycle and live near enough to cycle who are more positive about cycle facilities. A variety of cultural and societal constraints on cycle use are considered. Measures to encourage cycling in employer travel plans must reflect the gender balance in the organisation as well as recognised geographical and organisational factors.

Roles and functions of robots in human society: implications from research in autism therapy

Abstract: This paper discusses robots that are operational within a human-inhabited environment. Specifically, we identify different roles that such robots can adopt, reflecting different human-robot relationships. We discuss three different roles of robots in a project where we develop a robot as a therapeutic tool for children with autism: the robot as a therapeutic playmate, the robot as a social mediator, and the robot as a model social agent. Implications of these roles that go beyond this particular project are discussed.

Mycorrhizal colonisation improves fruit yield and water use efficiency in watermelon (Citrullus lanatus Thunb.) grown under well-watered and water-stressed conditions

Abstract: The effect of arbuscular mycorrhizal (AM) colonisation by Glomus clarum on fruit yield and water use efficiency (WUE) was evaluated in watermelon (Citrullus lanatus) cv. Crimson Sweet F1 under field conditions. Treatments were: (1) well-watered plants without mycorrhizae (WW-M), (2) well-watered plants with mycorrhizae (WW+M), (3) water- stressed plants without mycorrhizae (WS-M) and (4) water-stressed plants with mycorrhizae (WS+M). When soil water tension readings reached −20 and −50 kPa for well-watered (WW) and water-stressed (WS) treatments, respectively, irrigation was initiated to restore the top soil to near field capacity. Water stress reduced watermelon shoot and root dry matter, fruit yield, water use efficiency but not total soluble solids (TSS) in the fruit, compared with the non-stressed treatments. Mycorrhizal plants had significantly higher biomass and fruit yield compared to nonmycorrhizal plants, whether plants were water stressed or not. AM colonisation increased WUE in both WW and WS plants. Macro- (N, P, K, Ca and Mg) and micro- (Zn, Fe and Mn) nutrient concentrations in the leaves were significantly reduced by water stress. Mycorrhizal colonisation of WS plants restored leaf nutrient concentrations to levels in WW plants in most cases. This is the first report of the mitigation of the adverse effect of water stress on yield and quality of a fruit crop.