A study of the flora and invertebrate fauna of magnesian grassland (of Thrislington plantation SSSI), with particular reference to plant architecture and invertebrates

1/. Relationships between plant architecture and invertebrates have been widely described, (Lawton 1983 and 1986, Southwood, Brown and Reader, 1979). This study aimed to investigate some part of the invertebrate fauna with particular reference to plant architecture and the affects of disturbance. 2/.Thrislington was chosen as the study site as it consisted of a number of transplantated sites (Fig. 1). These represent a series of 8 Magnesian limestone grassland sites of known age and site history. Previous studies of die flora (Shimwell 1968 and Parks 1982 and 1989) and invertebrates (Sheppard, 1987 & 1989 and Woodford and Bruce, 1983) have produced a detailed history of this Grade 1 SSSI prior to it's transplant. 3/.A series of 25 fixed quadrats (2 square metres) were positioned throughout 5 of the 8 transplanted sites i.e. 1,3,4,6,8. Five quadrats were placed randomly within each of the five chosen sites. These quadrats formed the basis of die vegetation, architecture and invertebrate surveys. 4/.The survey yielded 82 plant species occuning within the fixed quadrats and 112 species throughout the 5 sites surveyed. The sites were found to become more homogeneous with increasing age. The diversity of plant species was greatest on site 6 (removed 3 years ago) with 84 species occurring on that site and lowest diversity on site 1 i.e. 59 species and moved 8 years ago. 5/.The architecture survey data and vegeatation data were used to run DCA analyses. The analyses were carried out on the individual quadrat data and both showed a certain degree of separating with respect to the sites they were taken from in diat vegetation (in terms of species) and architecture become increasing homogeneous with age, at Thrislington. The CCA analyses showed that % bare earth and % moisture content were most influencing the biplot along die first and second axes. 6/.A DCA and CCA analyses were carried out on weevils, spiders, carabids and "all invertebrates". The "invertebrate" CCA showed that site age (axis 1) and the height classes 0-2 & 2-5cm (2nd axis) explained the greatest amount of variance. The weevil CCA showed that pitfall position and 10-20cm were the two most important (measured) variables. The spider CCA showed the greatest association with average moss depth and 2-5cm. While the carabids showed the greatest association with 2-5cm and % moss cover. 7/.In addition to the quadrats and pitfalls further invertebrate groups were selected for study by different techniques - walking transect for butterflies, hand searches for molluscs and counts for Cercopidae nymphs within each of the 25 fixed quadrats. The butterfly transects revealed that the small heath was the commonest of the 13 species recorded and Site 3 had constantly high counts throughout the study period. The mollusc survey yielded 8 species (5 snails and 3 slugs). The commonest large snail was Cepaea nemoralis. No significant correlation was found between Cepaea numbers and environmental variables measured, using correlation coefflcents. The Cercopidae nymphs counts produced a total of 44 host plant species, five of which accounted for 80% of the total counts. An estimate of density was calculated for each site and an average density per square metre on. each of the four sampling occasions. Multivariate techniques using the DCA and CCA analyses run on the CANOCO programme were found to be a robust and reliable techniques for investigating the interrelationships between species and environmental variables

Using cognitive work analysis to explore activity allocation within military domains

Cognitive Work Analysis (CWA) is frequently advocated as an approach for the analysis of complex sociotechnical systems. Much of the current CWA literature within the military domain pays particular attention to its initial phases; Work Domain Analysis and Contextual Task Analysis. Comparably, the analysis of the social and organisational constraints receives much less attention. Through the study of a helicopter Mission Planning System (MPS) software tool, this paper describes an approach for investigating the constraints affecting the distribution of work. The paper uses this model to evaluate the potential benefits of the social and organisational analysis phase within a military context. The analysis shows that, through its focus on constraints the approach provides a unique description of the factors influencing the social organisation within a complex domain. This approach appears to be compatible with existing approaches and serves as a validation of more established social analysis techniques

Critical Analysis of Baryon Masses and Sigma-Terms in Heavy Baryon Chiral Perturbation Theory

We present an analysis of the octet baryon masses and the $\pi N$ and $KN$ $\sigma$--terms in the framework of heavy baryon chiral perturbation theory. At next-to-leading order, ${\cal O}(q^3)$, knowledge of the baryon masses and $\sigma_{\pi N}(0)$ allows to determine the three corresponding finite low--energy constants and to predict the the two $KN$ $\sigma$--terms $\sigma^{(1,2)}_{KN} (0)$. We also include the spin-3/2 decuplet in the effective theory. The presence of the non--vanishing energy scale due to the octet--decuplet splitting shifts the average octet baryon mass by an infinite amount and leads to infinite renormalizations of the low--energy constants. The first observable effect of the decuplet intermediate states to the baryon masses starts out at order $q^4$. We argue that it is not sufficient to retain only these but no other higher order terms to achieve a consistent description of the three--flavor scalar sector of baryon CHPT. In addition, we critically discuss an SU(2) result which allows to explain the large shift of $\sigma_{\pi N}(2M_\pi^2) - \sigma_{\pi N}(0)$ via intermediate $\Delta (1232)$ states.Comment: 18 pp, TeX, BUTP-93/05 and CRN-93-0

Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins

New formulation of relativistic wave equations (RWE) for massive particles with arbitrary half-integer spins s interacting with external electromagnetic fields are proposed. They are based on wave functions which are irreducible tensors of rank $n ($n=s-\frac12$) antisymmetric w.r.t. n pairs of indices, whose components are bispinors. The form of RWE is straightforward and free of inconsistencies associated with the other approaches to equations describing interacting higher spin particles

Is the Sun Embedded in a Typical Interstellar Cloud?

The physical properties and kinematics of the partially ionized interstellar material near the Sun are typical of warm diffuse clouds in the solar vicinity. The interstellar magnetic field at the heliosphere and the kinematics of nearby clouds are naturally explained in terms of the S1 superbubble shell. The interstellar radiation field at the Sun appears to be harder than the field ionizing ambient diffuse gas, which may be a consequence of the low opacity of the tiny cloud surrounding the heliosphere. The spatial context of the Local Bubble is consistent with our location in the Orion spur.Comment: "From the Outer Heliosphere to the Local Bubble", held at International Space Sciences Institute, October 200

Shapes, contact angles, and line tensions of droplets on cylinders

Using an interface displacement model we calculate the shapes of nanometer-size liquid droplets on homogeneous cylindrical surfaces. We determine effective contact angles and line tensions, the latter defined as excess free energies per unit length associated with the two contact lines at the ends of the droplet. The dependences of these quantities on the cylinder radius and on the volume of the droplets are analyzed.Comment: 26 pages, RevTeX, 10 Figure

Confounding experimental considerations in nanogenotoxicology

The development of novel nanomaterials with unique physico-chemical properties is increasing at a rapid rate, with potential applications across a broad range of manufacturing industries and consumer products. Nanomaterial safety is therefore becoming an increasingly contentious issue that has intensified over the past 4 years, and in response, a steady stream of studies focusing on nanotoxicology are emerging. However, it is becoming increasingly evident that nanomaterials cannot be treated in the same manner as chemical compounds with regards to their safety assessment, as their unique physico-chemical properties are also responsible for unexpected interactions with experimental components that generate misleading data-sets. In this report, we focus on nanomaterial interactions with colorimetric and fluorometric dyes, components of cell culture growth medium and genotoxicity assay components, and the resultant consequences on test systems are demonstrated. Thus, highlighting some of the potential confounding factors that need to be considered in order to ensure that in vitro genotoxicity assays report true biological impacts in response to nanomaterial exposure.status: publishe

Neutron cross-sections for advanced nuclear systems : The n-TOF project at CERN

© Owned by the authors, published by EDP Sciences, 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n-TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.Peer reviewedFinal Published versio

238U(n, γ) reaction cross section measurement with C 6D6 detectors at the n-TOF CERN facility

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe radiative capture cross section of 238U is very important for the developing of new reactor technologies and the safety of existing ones. Here the preliminary results of the 238U(n,γ) cross section measurement performed at n-TOF with C6D6 scintillation detectors are presented, paying particular attention to data reduction and background subtraction.Peer reviewe

High accuracy 234U(n,f) cross section in the resonance energy region

New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n-TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n-TOF neutron flux