Dynamic vergence telepresence system incorporating active gaze control

Visual Telepresence system which utilize virtual reality style helmet mounted displays have a number of limitations. The geometry of the camera positions and of the display is fixed and is most suitable only for viewing elements of a scene at a particular distance. In such a system, the operator's ability to gaze around without use of head movement is severely limited. A trade off must be made between a poor viewing resolution or a narrow width of viewing field. To address these limitations a prototype system where the geometry of the displays and cameras is dynamically controlled by the eye movement of the operator has been developed. This paper explores the reasons why is necessary to actively adjust both the display system and the cameras and furthermore justifies the use of mechanical adjustment of the displays as an alternative to adjustment by electronic or image processing methods. The electronic and mechanical design is described including optical arrangements and control algorithms, An assessment of the performance of the system against a fixed camera/display system when operators are assigned basic tasks involving depth and distance/size perception. The sensitivity to variations in transient performance of the display and camera vergence is also assessed.

What makes a Salmonella strain epidemic? An expert opinion workshop

An expert opinion workshop was held on the subject of the cause, identification and control of new and emerging Salmonella strains. Experts were invited to complete questionnaires, contribute to structured discussions and take part in cluster group tasks. Outputs of the workshop included that, with current surveillance methods, it might take up to 2.5 years from the first introduction of a new strain into the UK livestock population to its identification as a human epidemic strain. In order to reduce the time to detection and provide more effective control options, several recommendations were made, including better back-tracing of human cases to their source, which would require more effective communication between those responsible for human and veterinary surveillance.

Food and Health Forum meeting - nutritional approaches to cardiovascular health: workshop report

This report summarises the proceedings of a meeting held by the Food and Health Forum at the Royal Society of Medicine, London, on 12 October 2011. The objective of the meeting was to highlight nutritional strategies targeted at cardiovascular health. This included a review of the effects of various foods, nutrients and ingredients on maintenance of healthy cholesterol levels, endothelial function and blood pressure

Late Annibale and his workshop: invention, imitation and patronage

Discussion of the organisation of Annibale Carracci's workshop in his later years

Foreword: International Space Science Institute (ISSI) workshop on observing and predicting Earth’s energy flows

The Earth’s climate, as well as planetary climates in general, is broadly regulated by three fundamental parameters: the total solar irradiance, the planetary albedo and the planetary emissivity. Observations from series of different satellites during the last three decades indicate that these three quantities are generally very stable. The total solar irradiation of some 1,361 W/m2 at 1 A.U. varies within 1 W/m2 during the 11-year solar cycle (Fröhlich 2012). The albedo is close to 29 % with minute changes from year to year but with marked zonal differences (Stevens and Schwartz 2012). The only exception to the overall stability is a minor decrease in the planetary emissivity (the ratio between the radiation to space and the radiation from the surface of the Earth). This is a consequence of the increase in atmospheric greenhouse gas amounts making the atmosphere gradually more opaque to long-wave terrestrial radiation. As a consequence, radiation processes are slightly out of balance as less heat is leaving the Earth in the form of thermal radiation than the amount of heat from the incoming solar radiation. Present space-based systems cannot yet measure this imbalance, but the effect can be inferred from the increase in heat in the oceans where most of the heat accumulates. Minor amounts of heat are used to melt ice and to warm the atmosphere and the surface of the Earth.

Foreword: International Space Science Institute (ISSI) workshop on the Earth’s cryosphere and sea level change

Rising sea level is perhaps the most severe consequence of climate warming, as much of the world’s population and infrastructure is located near current sea level (Lemke et al. 2007). A major rise of a metre or more would cause serious problems. Such possibilities have been suggested by Hansen and Sato (2011) who pointed out that sea level was several metres higher than now during the Holsteinian and Eemian interglacials (about 250,000 and 120,000 years ago, respectively), even though the global temperature was then only slightly higher than it is nowadays. It is consequently of the utmost importance to determine whether such a sea level rise could occur and, if so, how fast it might happen. Sea level undergoes considerable changes due to natural processes such as the wind, ocean currents and tidal motions. On longer time scales, the sea level is influenced by steric effects (sea water expansion caused by temperature and salinity changes of the ocean) and by eustatic effects caused by changes in ocean mass. Changes in the Earth’s cryosphere, such as the retreat or expansion of glaciers and land ice areas, have been the dominant cause of sea level change during the Earth’s recent history. During the glacial cycles of the last million years, the sea level varied by a large amount, of the order of 100 m. If the Earth’s cryosphere were to disappear completely, the sea level would rise by some 65 m. The scientific papers in the present volume address the different aspects of the Earth’s cryosphere and how the different changes in the cryosphere affect sea level change. It represents the outcome of the first workshop held within the new ISSI Earth Science Programme. The workshop took place from 22 to 26 March, 2010, in Bern, Switzerland, with the objective of providing an in-depth insight into the future of mountain glaciers and the large land ice areas of Antarctica and Greenland, which are exposed to natural and anthropogenic climate influences, and their effects on sea level change. The participants of the workshop are experts in different fields including meteorology, climatology, oceanography, glaciology and geodesy; they use advanced space-based observational studies and state-of-the-art numerical modelling.

Large-scale surface mass balance of ice sheets from a comprehensive atmospheric model

The surface mass balance for Greenland and Antarctica has been calculated using model data from an AMIP-type experiment for the period 1979–2001 using the ECHAM5 spectral transform model at different triangular truncations. There is a significant reduction in the calculated ablation for the highest model resolution, T319 with an equivalent grid distance of ca 40 km. As a consequence the T319 model has a positive surface mass balance for both ice sheets during the period. For Greenland, the models at lower resolution, T106 and T63, on the other hand, have a much stronger ablation leading to a negative surface mass balance. Calculations have also been undertaken for a climate change experiment using the IPCC scenario A1B, with a T213 resolution (corresponding to a grid distance of some 60 km) and comparing two 30-year periods from the end of the twentieth century and the end of the twenty-first century, respectively. For Greenland there is change of 495 km3/year, going from a positive to a negative surface mass balance corresponding to a sea level rise of 1.4 mm/year. For Antarctica there is an increase in the positive surface mass balance of 285 km3/year corresponding to a sea level fall by 0.8 mm/year. The surface mass balance changes of the two ice sheets lead to a sea level rise of 7 cm at the end of this century compared to end of the twentieth century. Other possible mass losses such as due to changes in the calving of icebergs are not considered. It appears that such changes must increase significantly, and several times more than the surface mass balance changes, if the ice sheets are to make a major contribution to sea level rise this century. The model calculations indicate large inter-annual variations in all relevant parameters making it impossible to identify robust trends from the examined periods at the end of the twentieth century. The calculated inter-annual variations are similar in magnitude to observations. The 30-year trend in SMB at the end of the twenty-first century is significant. The increase in precipitation on the ice sheets follows closely the Clausius-Clapeyron relation and is the main reason for the increase in the surface mass balance of Antarctica. On Greenland precipitation in the form of snow is gradually starting to decrease and cannot compensate for the increase in ablation. Another factor is the proportionally higher temperature increase on Greenland leading to a larger ablation. It follows that a modest increase in temperature will not be sufficient to compensate for the increase in accumulation, but this will change when temperature increases go beyond any critical limit. Calculations show that such a limit for Greenland might well be passed during this century. For Antarctica this will take much longer and probably well into following centuries.

A Possible Change in Mass Balance of Greenland and Antarctic Ice Sheets in the Coming Century

A high-resolution GCM is found to simulate precipitation and surface energy balance of high latitudes with high accuracy. This opens new possibilities to investigate the future mass balance of polar glaciers and its effect on sea level. The surface mass balance of the Greenland and the Antarctic ice sheets is simulated using the ECHAM3 GCM with TI06 horizontal resolution. With this model, two 5-year integrations for the present and doubled carbon dioxide conditions based on the boundary conditions provided by the ECHAM1/T21 transient experiment have been conducted. A comparison of the two experiments over Greenland and Antarctica shows to what extent the effect of climate change on the mass balance on the two largest glaciers of the world can differ. On Greenland one sees a slight decrease in accumulation and a substantial increase in melt, while on Antarctica a large increase in accumulation without melt is projected. Translating the mass balances into terms of sea-level equivalent. the Greenland discharge causes a sea level rise of 1.1 mm yr−1, while the accumulation on Antarctica tends to lower it by 0.9 mm yr−1. The change in the combined mass balance of the two continents is almost zero. The sea level change of the next century can be affected more effectively by the thermal expansion of seawater and the mass balance of smaller glaciers outside of Greenland and Antarctica.

A study of the microstructure and condition of thin sheets of painting support ivory using SEM and ESEM

This paper outlines a study of the microstructure of thin sheets of ivory used as a painting support for portrait miniatures. Warping of the ivory support is one of the main problems commonly found in portrait miniatures from the late eighteenth century and early nineteenth century. Portrait miniatures from this period are painted on very thin sheets of ivory that are often only 0.2 mm in thickness. Warping can lead to cracking of the ivory and can also accentuate flaking of the paint layer. The problem of warping in ivory has thus been of long-term interest to conservators who deal with portrait miniatures, including those at the Victoria and Albert (V&A) Museum. The causes of warping are complex. However, it should be noted that artists normally stuck the thin ivory sheets onto paper or card before commencing the painting. The possible causes of warping therefore are thought to relate to the differential reactions of the ivory/adhesive/paper or card layers to changes in relative humidity (RH). It is well known that ivory is hygroscopic and anisotropic.1 However, only a few scientific studies have been carried out related to this subject and systematic analyses of the morphological and microstructural changes due to changes in RH or moisture in such thin sheets of ivory have yet to be investigated.

Using Delboeuf's illusion to improve point and click performance for older adults

Older computer users often exhibit poorer performance in point and click tasks on a computer than younger adults. This paper reports on the first phase of research that examines whether a visual illusion that makes an object appear to be larger (Delboeuf‟s Illusion), can help to improve point and click performance for older computer users. In this first phase, we look at the effect sizes for different configurations of the Delboeuf illusion. The study finds that the target size is overestimated by 8% for both older and younger adults in one configuration, and 12% for older adults in another configuration. The results will inform the design of a second phase, in which the configurations which demonstrate the largest effects will be investigated using a Fitts‟-style study of pointing performance.

Lightning-induced extensive charge sheets provide long range electrostatic thunderstorm detection

By combining electrostatic measurements of lightning-induced electrostatic field changes with radio frequency lightning location, some field changes from exceptionally distant lightning events are apparent which are inconsistent with the usual inverse cube of distance. Furthermore, by using two measurement sites, a transition zone can be identified beyond which the electric field response reverses polarity. For these severe lightning events, we infer a horizontally extensive charge sheet above a thunderstorm, consistent with a mesospheric halo of several hundred kilometers’ extent.

Variation among Attic fine wares: the case of the Pan Painter's pelikai

This paper is a case study of the continuum between standardization and variation in the production of red-figure Athenian fine wares in the first half of the 5th century BC. An investigation of the Pan Painter's pelikai reveals that they fall into 3 distinct groups, according to size. While the pelikai in each group are also distinguishable from each other by shape, pattern, and iconography, the next clearest distinction between the groups (after size) is in their style of decoration. The pelikai in the largest group, which is comprised of small pelikai, are particularly distinct from the Pan Painter's broader oeuvre of ca. 220 vases insofar as they exemplify a lackadaisical painting style, which I have termed banausic, on account of its frequent use for images of craftsmen, women at work, and other such genre images. While this casual style is antithetical to the Pain Painter's refined style, for which he is better known, and which he employs for his large pelikai, affinities between the 2 styles—as judged by his confident line, anatomical details, and other technical features—permit the conclusion that this group of pelikai were executed by one and the same craftsman as the others. As with all of the vases attributed to this talented painter, however, the pelikai—whether large or small—are decorated with a great bariety of images. While most painted Athenian vases are understood to have been individually created, not mass-produced, the Pan Painter's coherent group of small pelikai seem to have been created en masse, in a uniform size and shape and with a distinct decorative style. This group of standardized vases represents a body of work executed under the influence or at the behest of a specific vase workshop. The form of the small pelikai in fact allows us to associate them with the Geras Painter. With his work on these small pelikai, perhaps in the latter part of his career, the Pan Painter may have intentionally minimized variability in favour of standardization, to meet market demands.