Status of coral reefs of Little Cayman, Grand Cayman and Cayman Brac, British West Indies in 1999 and 2000. (Part 1: Stony corals and algae)

A benthic assessment of the isolated Cayman Islands was completed at 42 sites. Major changes in the reef community structure were documented by comparison with earlier studies. Acropora palmata and A. cervicornis, once abundant as shallow framework builders, were uncommon. Diseased stony corals were seen in \u3e90% of the study sites, with the highest averages in Little Cayman, especially at Bloody Bay which is one of the most highly regulated marine parks in the Cayman Islands. The Montastraea annularis species complex accounted for two-thirds of the diseased corals which, along with other massive species, were affected largely by white-plague disease. Recent partial-colony mortality was particularly high in Grand Cayman. However, small- to intermediate-sized (M. annularis complex) suggest a strong potential for population regeneration. Algal competition generally did not appear to be a problem for stony corals, and bleaching was insignificant, yet more prevalent, in the deeper (\u3e10 m) sites

Exactly solvable model of dissipative vortex tunneling

I consider the problem of vortex tunneling in a two-dimensional superconductor. The vortex dynamics is governed by the Magnus force and the Ohmic friction force. Under-barrier motion in the vicinity of the saddle point of the pinning potential leads to a model with quadratic Hamiltonian which can be analytically diagonalized. I find the dependence of the tunneling probability on the normal state quasiparticle relaxation time $\tau$ with a minimum at $\omega_0\tau\sim 1$, where $\omega_0$ is the level spacing of the quasiparticle bound states inside the vortex core. The results agree qualitatively with the available experimental data.Comment: RevTeX, 6 pages, 2 figures. Published versio

Effects of environmental conditions on the micro-mechanical properties of formulated waterborne coatings

Waterborne colloidal polymer coatings are widely used in architectural and agricultural applications where they are subject to challenging environments, such as extremes of temperatures and relative humidities (RH). This research investigates the effects of adding two common co-formulants, poly(acrylic acid) (PAA) and xanthan gum (XG), to waterborne polymer composite coatings in these environments. The mechanical properties of the resulting coatings are of particular interest. Hardness, creep and tack properties of thick (similar to 400 mu m) formulated model coatings were characterized using a micro-indentation technique operating in a single cycle within a bespoke environmental chamber. Measurements were made at three temperatures (16, 20 and 30 degrees C), which span the glass transition temperature (T-g) of the acrylic copolymer binder, and over three RH values of 10%, 43%, and 90%. The creep data were analysed using the Burgers model to extract characteristic viscoelastic properties. The tack was found by recording the force when withdrawing the probe from the sample and using it to obtain nominal stress (knowing the indentation depth and probe geometry) during the indenter's withdrawal and hence the work of adhesion (W-Adh) to detach from the coating. Tack adhesion is completely lost below the binder's T-g but increases when the ambient temperature increases. In formulated coatings, both the tack and creep deformation increase as the relative humidity increases, and this trend is observed at each temperature. There is no evidence from thermal analysis for plasticization of the acrylic polymer by moisture sorption, but the two co-formulants are hydrophilic. The observed softening of the coatings at high RH can be attributed to water sorption in the components. The presence of glassy PAA has the effect of raising the hardness of glassy coatings, but only at low RH when there is no plasticization by water. The addition of hydrophilic XG surprisingly reduces tack adhesion while also raising the viscosity of the coating. These findings will inform the formulation of waterborne colloidal coatings to function in a range of environments.work was funded by EPSRC (Grant EP/L016788/1) through the Doctoral Training Centre in Micro- and NanoMaterials and Technology (MiNMaT). We benefited from useful discussions with Dr. Marco Ram- aioli (INRAE, AgroParisTech - Center de Massy) and Dr. Nicholas Ballard (University of the Basque Country). We thank Violeta Doukova and Dave Jones (University of Surrey) for laboratory assistance and Dr. Agata Gajewicz-Jaromin for performing DSC and TGA analyses. We also thank Dr. James Adams (Cubica Technology) for his assistance in writing data analysis scripts. We thank Richard Turner (Acal BFI UK Ltd.) for the relative humidity and temperature probes, and for his assistance with their setup

Improved lower bounds for the ground-state energy of many-body systems

New lower bounds for the binding energy of a quantum-mechanical system of interacting particles are presented. The new bounds are expressed in terms of two-particle quantities and improve the conventional bounds of the Hall-Post type. They are constructed by considering not only the energy in the two-particle system, but also the structure of the pair wave function. We apply the formal results to various numerical examples, and show that in some cases dramatic improvement over the existing bounds is reached.Comment: 29 pages, 5 figures, to be published in Phys. Rev.

Weight-related quality of life in obese, pregnant women in South Africa

Objective: The global obesity pandemic includes pregnant women. Obesity may negatively impact quality of life (QOL). A validated, obesity-specific, QOL  assessment tool was used to assess the impact of obesity on five specific domains.Methods: A prospective cohort study was performed at Tygerberg Academic Hospital in South Africa. Morbid obesity was defined as a body mass index (BMI) of 40–49.9 kg/m2 and super-obesity as BMI > 50 kg/m2, using the first recorded weight during the pregnancy. Pregnant women with a BMI ≥ 40 were approached in the high-risk antenatal clinic where written informed consent was taken before  recruitment. Using the QOL tool they answered statements about their current  experiences.Results: A total of 66 morbidly obese and 46 super-obese women were enrolled  across an age range of 18–45 years. Physical function and self-esteem were the domains with the lowest QOL scores. When comparing morbid with super obesity, all scores were significantly lower in the latter group except for the domains of  self-esteem and sexual life.Conclusion: Morbid and super-obesity occur across the full spectrum of the adult reproductive period. Physical function and self-esteem are most affected while QOL is linked to the degree of obesity.Keywords: obesity, pregnancy, quality of life, morbid obesity, super-obesity

Effect of La doping on magnetic structure in heavy fermion CeRhIn5

The magnetic structure of Ce0.9La0.1RhIn5 is measured using neutron diffraction. It is identical to the incommensurate transverse spiral for CeRhIn5, with a magnetic wave vector q_M=(1/2,1/2,0.297), a staggered moment of 0.38(2)Bohr magneton per Ce at 1.4K and a reduced Neel temperature of 2.7 K.Comment: 5 pages, 2 figures, 1 table. Conf. SCES'200

Using learning design as a framework for supporting the design and reuse of OER

The paper will argue that adopting a learning design methodology may provide a vehicle for enabling better design and reuse of Open Educational Resources (OERs). It will describe a learning design methodology, which is being developed and implemented at the Open University in the UK. The aim is to develop a 'pick and mix' learning design toolbox of different resources and tools to help designers/teachers make informed decisions about creating new or adapting existing learning activities. The methodology is applicable for designers/teachers designing in a traditional context – such as creation of materials as part of a formal curriculum, but also has value for those wanting to create OERs or adapt and repurpose existing OERs. With the increasing range of OERs now available through initiatives as part of the Open Courseware movement, we believe that methodologies, such as the one we describe in this paper, which can help guide reuse and adaptation will become increasingly important and arguably are an important aspect of ensuring longer term sustainability and uptake of OERs. Our approach adopts an empirically based approach to understanding and representing the design process. This includes a range of evaluation studies (capturing of case studies, interviews with designers/teachers, in-depth course evaluation and focus groups/workshops), which are helping to develop our understanding of how designers/teachers go about creating new learning activities. Alongside this we are collating an extensive set of tools and resources to support the design process, as well as developing a new Learning Design tool that helps teachers articulate and represent their design ideas. The paper will describe how we have adapted a mind mapping and argumentation tool, Compendium, for this purpose and how it is being used to help designers and teachers create and share learning activities. It will consider how initial evaluation of the use of the tool for learning design has been positive; users report that the tool is easy to use and helps them organise and articulate their learning designs. Importantly the tool also enables them to share and discuss their thinking about the design process. However it is also clear that visualising the design process is only one aspect of design, which is complex and multi-faceted

Patient profi le of a tertiary obstetric-cardiac clinic

Background: Cardiac disease is the most important medical cause of maternal mortality in South Africa. Management of women with cardiac disease in pregnancy is highly specialised and they should ideally be evaluated early in pregnancy and in a multidisciplinary fashion with the aim of formulating a perinatal management plan. In order to facilitate the effi cient management of these patients in the context of a large tertiary hospital in South Africa a combined obstetric-cardiac (O-C) clinic was established at Tygerberg Academic Hospital (TBH) in 2010. Objective: The purpose of this review is to describe the patient profi le of an obstetric-cardiac clinic in South Africa, specifi cally the TBH O-C clinic and to share thelessons learnt from establishing this clinic. Methods: Retrospective review performed at TBH, a referral centre in the Western Cape Province of SouthAfrica. All women evaluated and/or managed at the Obstetric-Cardiac clinic between 10 August 2010 and 4 December 2012 were included. Results: There were 231 women, rheumatic heart disease (n=79; 34.2%) was the predominant cardiac disease followed by congenital heart disease (n=78; 33.8%), medical conditions (n=38; 16.4%) and previous peripartum cardiomyopathy (n=9; 3.9%). Eighty-two women (35.5%) were perceived to be extremely high risk and their entire pregnancies were managed in the Obstetric-Cardiac clinic. The most common RHD lesion was mitral regurgitation (34.2%) and mixed mitral valve disease (24.1%). The most frequent CHD was ventricular septal defects (n=27; 35%). Conclusions: The cardiac disease profi le of patients seen at this obstetric-cardiac clinic in a South African tertiary hospital refl ects a transition from the disease profi le of a typical developing country (high burden of rheumatic heart disease) to the disease profi le seen in a more developed country (high burden of congenital heart disease). This could indicate improved quality of socio-economic development and the health care system. The increasing complexity of cardiac pathology that has to be dealt with in pregnant patients presenting to a tertiary hospital requires close collaboration between the obstetrician, cardiologist, cardiac surgeon and anesthetist caring for these patients. A dedicated obstetric-cardiac clinic is a good model to utilise in a tertiary hospital when aiming to optimise the care of patients with cardiac disease in pregnancy

A More Flavored Higgs boson in Supersymmetric models

A More flavored Higgs boson arises when the flavor structure encoded in SUSY extensions of the SM is transmited to the Higgs sector. The flavor-Higgs transmition mechanism can have a radiative or mixing origin, as it is illustrated with several examples, and can produce interesting Higgs signatures that can be probed at future high-energy colliders. Within the MSSM, the flavor mediation mechanism can be of radiative type, as it is realized trhough gaugino-slepton loops, which transmit the flavor structture of the soft-breaking sector to the Higgs bosons. In particular we focus on evaluating the contributions from the general trilinear terms to the lepton flavor violating Higgs (LFV) vertices. On the other hand, as an example of flavor mediation through mixing, we discuss an E_6 inspired multi-Higgs model, with an abelian flavor symmetry, where LFV as well as lepton flavor conserving Higgs effects are found to arise, though in this case at tree-level. We find that Tevatron and LHC can provide information on the flavor structure of these models through the detection of the LFV higgs mode h-> tau+mu, while NLC can perform high-precision measurements of the LFC mode h-> tau tau.Comment: 17 pages, 5 tables, 3 figures; corrected mistake in last section, results changed but conclusions remmai