25th November 2015Shake, Wobble and Roll - Resonating with Digital BitsDr Peter Bennett Peter Bennett is a post-doc researcher in human-computer interaction at the Bristol Interaction & Graphics Lab at University of Bristol. His research is driven by the aim of joining the digital world with the real world of objects, and in doing so allowing people to physically interact with computers through Tangible User Interfaces. His fascinating and conceptual talk is best understood by considering two scientific concepts (feedback and resonance) and their combination in the context of human/machine interactions. ‘Feedback’ is the process by which a system or sub-system is modulated or controlled in response to its own output. ‘Resonance’ is where an external force drives a vibrating system amplifying its natural vibration. A central heating thermostat is, for example, a feedback mechanism. It not only controls the temperature of the heating system, but is itself modified by the output from the heating-system it controls. A person-on-a-swing is the usual, non-technical example of a resonant system. One small push (input) at the right time can produce a substantial swing. In other words, small, regular nudges can give big outputs. The combination of these phenomena was first investigated in the 19th century by scientists seeking rational causes for supposed ‘supernatural’ events, for example the Ouija board or water dowsing. This led to the discovery of the ideomotor response whereby a thought or mental image brings about reflexive or automatic, micro-muscular reaction, often outside of the awareness of the subject. For example, a spiritualist may hold up a pendulum, supporting it between their finger and thumb. Seemingly without human cause, the pendulum starts to swing before an incredulous audience who may feel obliged to attribute the movement to a supernatural influence. In fact, it can be shown that the spiritualist’s act of observing the pendulum that they are holding can lead to micro-movements by their finger and thumb, causing the pendulum to start swinging. The spiritualist could, of course, be a con-artist or may, alternatively, have innocently convinced themselves of a supernatural influence and be guilty of nothing more than naivety. The ideomotor reflex can be demonstrated with more modern equipment. By holding an iPhone in which a rapidly moving pattern is generated by small movements of the instrument, the iPhone holder can, by concentrating on the changing pattern, stabilise the pattern using the ideomotor effect. Development of such technologies, driven by the ideomotor response, can therefore provide a potential mechanism for interfacing with computer systems in new and seamless ways. Peter’s introduction to this area has been by way of Cybernetics (M.Eng, Reading), Digital Media, Arts and Design (M.A. Brighton) and Musical Instrument Design (PhD Queens, Belfast) and he has pursued practical applications in several areas at Bristol University. This lead to experiments with the sense of touch, developing devices, for example, to push through a waveform and the BeatBearing, a drum machine with ball bearings for notes. Some of the work has been done is association with magician Stuart Nolan. There are ongoing projects and collaborations including the development of magical technology, magnetic pixels, teleporters, robot origami, lo-fi haptic displays, resonant taste, wobbly surfaces, which self-wobble to get attention, and Slow Technology where resonant interaction with technology is slowed to make engagement more fulfilling Other projects have included the ChronoTape, an augmented-reality paper timeline for annotating family research history whereby a timeline tape allows for photographs to be inserted at appropriate points on the tape. A larger version of this, the ChronoTable allows archaeologists at digs to plot all details of their activity on a timeline. During the past 2 years, Peter has been involved in the Residential Home-based Tangible Memories project which puts residents’ personal life stories and memories into physical objects so that they can remind themselves of important memories and share them with others, thereby providing a more satisfying Residential Home experience. It is early days for this relatively new sub-discipline. Whilst applications are yet to be commercially available, it is clear that with the domination of contemporary life by digital machines, such technology will be essential for the harmonious co-habitation of humans and computers. For further information:
Report by Simon Webster
28 October 2015A History of AnaesthesiaDr Andrew Johnson
October's meeting welcomed Dr Andrew Johnson, a consultant anaesthetist at the Oxford Hospitals NHS Foundation Trust, and prior to that, a doctoral researcher in the same discipline. Whilst often seen as a minor preliminary to the surgical procedure itself, anaesthesia is very much at the forefront of modern medicine. It is regarded by some as the ‘Greatest of Advances in Modern Medicine’. Before general anaesthesia, surgery was a last resort. The key quality of a pre-anaesthesia surgeon was speed rather than skill. Peripheral surgery (amputation) was possible, but body cavity surgery could not be contemplated.
The search for suitable anaesthetics is as old as written history. Opium poppies were used ~4000 BC; later, other herbs such as henbane and mandrake were used in various cultures. The Chinese, unsurprisingly, advocated the use of acupuncture.
The era of more modern anaesthetics started with Humphrey Davy’s observation in 1800 that Nitrous Oxide reduces physical pain, noted by him many years before it was actually used medically. In later decades, ether was used, initially on animals, and first demonstrated publicly on humans by dentist William Morton in the 1840’s. Ether had the advantage over Nitrous Oxide that it is a more potent anaesthetic. However, being highly flammable, patients risked not only death from surgically-induced sepsis, but conflagration from the ignition of highly flammable ether vapour. Operation theatre explosions were not uncommon, ‘taking out’ not only the unfortunate patient (hopefully too subdued to suffer in the explosion) but also surgeons and operating staff. Later, chloroform, a safer alternative, began to be used, and gained social acceptability when used by the Royal surgeon, John Snow, on Queen Victoria during the births of Prince Leopold and Princess Beatrice. (John Snow was the 'father' of epidemiology having famously tracked the source of a cholera outbreak in the capital in 1854 to a single pump dispensing contaminated water).
Medicine’s search for ever more potent anaesthetics procured effective agents but with the age-old problem of combustibility. In the 1920’s, the Germans flirted with acetylene (used in oxyacetylene gas welding) as an anaesthetic. At around the same time, cyclopropane, with excellent anaesthetic qualities, was introduced. Dr Johnson reported that in one operating theatre explosion using cyclopropane, two anaesthetists and two surgeons were killed and two nurses seriously injured with both requiring amputations.
The need for safer anaesthetics led to the use of halogenated volatile anaesthetics, with carbon-halogen bonding giving the greater stability than purely carbon-hydrogen bonding of earlier anaesthetics such as cyclopropane. Halothane, the most familiar, introduced in 1956, was in use until very recently and variants regularly introduced with Sevoflurane being the most recently developed. New chemicals continue to be advocated as anaesthetics, the most recent being the noble gas, Xenon.
Various theories have been put forward to account for anaesthetic effects of various agents on the body. None is comprehensive and this remains an active area of research.
Questions and discussion after the talk showed that uncertainties within the field remain. Anaesthetics may well affect the memory and there is strong evidence that an extensive history of anaesthetic interventions can lead to early onset Alzheimer's, possibly also exposing theatre staff to similar risks in spite of scavenging spent gases. Depth of anaesthesia can be determined by an electro-encephalogram, though this is not universally accepted as adequately determining degree of unconsciousness, and the concentration of an aesthetic in the brain cannot be measured directly but by proxy measurement of anaesthetic concentration of expired gases. All suggesting that whilst anaesthesia is firmly grounded in science, it's application is still very much an art. Report by Simon Webster
23 September 2015Après le déluge: how we might live with floodingDr Hadrian Cook Dr Hadrian Cook, a hydrologist and senior lecturer in sustainable development from Kingston University, spoke about the problem of flooding and the measures that might be taken to deal with and mitigate its effects. January 2014 saw severe flooding, not least on the Somerset levels, and the Intergovernmental Panel on Climate Change predicts increases in the frequency and severity of flooding. Dr Cook listed the main types of flooding: river overtopping and groundwater saturation are both natural effects, but increased surface run-off, particularly from building on flood plains, is largely caused by human activity. Failure of infrastructure, for example burst pipes or blocked drains, exacerbates the problems. Addressing these problems requires an inter-disciplinary approach with the expertise of natural scientists, engineers and social scientists. Flooding is a complex problem and its effects carry serious social, economic and environmental consequences. He raised and attempted to answer a number of questions, including who pays for flood defences and how can communities and central government work together; should agricultural land be flooded to save urban areas and what roles do water-meadows and flood-plains play? He identified the concept of ‘wicked problems’, when social and technical uncertainties are both high: flooding is a good example. Difficult decisions are needed which are best taken when it’s dry. Dr Cook’s home patch is Salisbury, and he showed examples of the flooding of the Cathedral and city in 1915. He also described the flooding of the Somerset levels and the efforts of the various agencies to deal with the problem and the reaction of people locally. He discussed the problem of coastal erosion and the economic arguments for and against attempting to prevent it. In summary there are 5.2 million properties in England at risk of flooding, with an estimated annual damage cost of over £1 billion. This could rise dramatically in the future. Report by Bob Barber
22 July 2015The Application of Geophysics to Egyptian Archaeology: Some Case StudiesJeffrey Spencer Jeffrey Spencer gave a very interesting lecture on the use of new technology in the investigation of historical sites in Egypt at the last meeting of the summer. He explained that the course of and depth of the Nile was different 3,000 years ago and this explains the position of some recent discoveries. Much of his work, for the British Museum, was centred on Tell el-Balumun in the Nile delta. The techniques he outlined included :Accoustic Pulse – sonar waves as used in Oil ExplorationGM Pulse - short pulse radar, which relies on interference patterns to detect objectsMagnetometers – sensors attached to the body which can detect the strength of a magnetic field, and therefore its gradient to help detect archeological features below the soil surfaceSatellite pictures – showing ‘footprints’ from space He explained how volunteers were required to wear some of these sensors as they surveyed the grid pattern of the site by walking along the grid lines. This means that in surveying a 40 hectare site, taking readings at 85 cm. intervals requires 250 km of walking – no mean feat in temperatures in excess of 40C! Report by Rob Bygrave
24 June 2015Dice WorldBrian Clegg Brian Clegg is a science journalist and author who has written many books on scientific subjects. This talk was based on his book “Dice World”, which looks at how our misunderstanding of probability and randomness affects our view of the world. Drawing both on classical erroneous beliefs such as the Gambler’s Fallacy and current news stories he described some of the superstitions that hold sway in our lives and explained that they often arise from an overreach of our extraordinary pattern-spotting abilities. He mentioned the difference between “real” randomness and the unpredictability of data arising from very complex, often chaotic systems such as weather systems and the stock market. He talked about the limitations on weather forecasts and was really rather disparaging about Economists. We were amused by his account of how easy we are to gull by such operations as the Race Horse Scam, where a trickster can convince a group of people that he can predict race winners. The way to do it is to start with a large number of people and tip each horse to one section of them. You then forget about everyone who was told a non-winner and divide up your winners’ group for a second race. After you have done this four or five times you are left with a small band of very impressed people who may well be willing to pay you for more racing tips. In his final section he tackled a classic probability dilemma which continues to show us how our pattern-seeking brains produce an intuition that can be very flawed. This is generally known as “The Monty Hall” problem and concerns the best strategy for winning an “open the box” type TV game show. Look it up if you want to find out whether your intuition is better than that of the thousands of highly qualified people who wrote in to Parade Magazine to pour scorn on the correct answer. Report by Louise Furre
27 May 2015New Hope for Spinal Cord InjurySenior Lecturer, The School of Biomedical Sciences, Leeds University. Sue Marks was a pupil at Lord Digby’s School. As Dr Susan Deuchars she returned to Sherborne to give an erudite insight into the world of those unfortunate patients with spinal injury. She explained that 80% of patients were males and that traffic accidents, falls, and sport were the main causes of injury. Motorbikes are the main cause of the accidents and the average age of the patients is 40 years. Because the spinal cord is damaged the effects occur in many parts of the body since the autonomic nervous system is disrupted, and this controls many of our bodily functions. Therefore some of the following problems are often found with spinal injury : high blood pressure, incontinence, sexual malfunction, pressure sores, pneumonia and lack of mobility. Unfortunately depression and suicide are also not uncommon. However Dr Deuchars was optimistic that the latest research, including her own, was bringing hope to the people suffering in this way. She has been trying to encourage new nerve cells to grow. This process known as neurogenesis can be used in a graft of stem cells into the damaged area of the spinal cord. Various techniques are used to cultivate the cells and her team at Leeds have recently found that limited amounts of red wine, dark chocolate and even nicotine can encourage neurogenesis. So – maybe - there is hope for us all yet!! The lecture was very well received by the audience which included some old girls from the Lord Digbys. Dr Deuchars is clearly making great progress in improving the lives of people with spinal cord injuries - and has acquired some ‘Yorkshire Grit’ along the way.
22 April 2015 People, People, People: Why the Green Movement Campaigns against GM Crops Professor Rod Scott, Bath University
Rod Scott, a plant geneticist and Professor of Biology at the University of Bath, took as his topic the attitude and objections of the Green Movement to genetically modified (GM) crops. The world’s population is continuing to increase, and our ability to feed ourselves has been a major subject of study and debate. Thomas Malthus (1766-1834) advanced the argument that a population that increased exponentially while food production increased linearly would inevitably reach a point of catastrophic starvation when the food reserves were exhausted. This has not happened, although famines have occurred. Ester Boserup (1910-1999) explained that human ingenuity has allowed advances in agricultural methods which have increased output and largely kept pace with population growth. This ‘green revolution’ has been achieved by plant breeding, increased production of fertilisers, mechanisation, irrigation and the use of pesticides and herbicides. Concerns have been raised that these advances will be insufficient to support continued human population growth, predicted to exceed 9 billion by 2050.The advent of GM crops offers a possible solution, and has been adopted in a number of areas: 81% of cotton in India is now GM as is 80% of the world’s soya. Advocates of GM claim increased yields, more efficient use of existing land, better drought resistance and the need for less chemical application. However, the green movement argues that we are heading for an environmental disaster with dramatically reduced biodiversity and that GM is unnecessary: the same results can be achieved with sustainable, organic methods. One company, Monsanto, dominates the GM market which risks a damaging monopoly. Prof Scott outlined the emergence of the Sierra Club in 1892 in the US, and described its later offshoots, Greenpeace and Friends of the Earth. He also discussed the changing attitude of the media, initially hostile, but more recently supportive. He pointed out that mutation breeding, for example by irradiation of seeds to impart genetic mutations, has been carried out for decades, without regulation. The green movement accepts this while objecting to GM, a technique which needs very detailed understanding of the underlying genetics. These ideas were explored further in a lively session of questions
Report by Bob Barber
25 March 2015
How on Earth Do You Measure Colour?
Dr Andrew Hanson
Andrew Hanson, Outreach Manager at the National Physical Laboratory (NPL) entertained us with some eye-opening visual illusions during his talk on the nature and measurement of colour. He began by outlining the role of the NPL as the national measurement laboratory. It sets and maintains traceable standards in a wide range of fields including the UK mass standard, acoustics, radiation and radioactivity as well as light. It is involved in international projects aimed at defining standards in terms of fundamental physical constants, giving completely independent methods of checking standards.
Andrew then described light in terms of its physical properties; light can be seen to behave both as a wave and a particle. Light as detected by the eye occupies a narrow band of wavelengths in the electro-magnetic spectrum, from 400-700nm. Colour is a qualitative description given to the response of the brain to light detected by the eye. Andrew described a 3-stage process: from light source → spectral filter → detection; each stage being a function of wavelength. The human eye has three colour detectors, with peak responses broadly in the blue, green and red parts of the light spectrum. Then followed an account of the attempt to specify colour objectively, based on experiments on human observers begun in the 1920s by William David Wright and John Guild. The International Commission on Illumination (CIE) eventually developed the CIE XYZ space, a development of the RGB colour space. Thus it established quantitative links between the physical definition of colour in terms of wavelength and physiologically perceived colour in humans. For more information see: http://en.wikipedia.org/wiki/CIE_1931_color_space
Andrew then demonstrated a number of ways that we can be fooled when attempting to describe colour. Apparent colours can be generated, e.g. by a rotating disc of black lines on a white background (Benham’s disk), and can appear to change depending on their surroundings and lighting conditions. Continuous stimulation with one colour can cause the eye to ‘saturate’, leaving an afterimage of complementary colour. Colour constancy ensures that perceived colours remain relatively constant under varying illuminations.
After a lively session of questioning we were left wondering when and whether we can believe what we see.
Report by Bob Barber
25 February 2015Dr Ben Johnson What Are Climate Models, and What Do They Tell Us About Climate Change? Ben Johnson, from the Meteorological Office in Exeter, tackled the controversial topic of climate change by firstly looking at the evidence that the Earth’s climate is changing. The global average surface temperature has been measured since the 1850s, and has been clearly rising since the 1960s and is now about 0.85C above its level in the late 19th century. Global sea level is currently rising at 3mm/y, mainly due to thermal expansion, the Arctic sea ice is receding and glaciers are shrinking. Ben next discussed the possible causes of these changes and described the ‘greenhouse effect’, a process first described by John Tyndall in the 1850s. Water vapour, carbon dioxide and methane are all known to absorb in the infra-red region; thus heat from the Sun remains trapped within the atmosphere, rather than being reflected back into space. Water vapour is the dominant greenhouse gas in the atmosphere, but it is the increase in levels of CO2 that is of most concern. Measurements from ice cores over 800,000 years show a cyclic pattern, but with levels below 300ppm until a sharp rise beginning in the 1950s. The level exceeded 400ppm for the first time in 2014. The possible natural causes of this rise were outlined, as well as the man-made contribution, mainly from the burning of fossil fuels. Ben next turned to the mathematical modelling of the climate, and showed how an essentially simple problem of energy balance can be used to set up equations that describe the many factors that can influence the system. The atmosphere needs to be considered in three dimensions. By applying the known physics of thermodynamics and Newton’s laws of motion, with the use of massive computer power, predictions of the future state of the climate can be made. The models can also be tested to see how well they match past observations. Ben showed diagrams of the effect on global temperature of a range of scenarios, including the uncontrolled expansion of CO2 emissions. Temperature rises of 5-6C by the end of the century are likely, with even higher rises in some parts of the globe. Even a complete cessation of CO2 emissions could still see rises; there are uncertainties about the effect of processes in the vast thermal reservoir of the oceans. Ben handed out a short quiz before his talk, to test our preconceptions, and discussed the answers at the break. He also handed out Met Office brochures which summarised the scientific consensus on the problem, based on the International Intergovernmental Panel on Climate Change’s 5th report. Its main conclusion is that warming of the climate is unequivocal. It is extremely likely (>95% confidence) that human influence has been the dominant cause. Ben led an interesting session of questions, which was wide-ranging and thought-provoking. Report by Bob Barber
25 January 2015Seeing is BelievingDr Simon Frackieweicz Dr Simon Frackieweicz made a return visit to Sherborne Science Café on 25th January. He has told us before about his excellent work in Kenya with the Akamba tribe. He makes regular visits to Kenya in his own time and treats their medical problems relating to sight. This time he explained, in great detail, exactly how a ‘normal’ eye works and the defects that may occur. He also explained how the brain interprets the sensory information it receives from the optic nerve and the errors that may occur in this process. ’Optical illusions’ can occur quite frequently without us realising. He described many conditions which could be caused by genetics, injury, stroke, or just old age. His particular specialisms include squint, lazy eye and double vision. Some of the conditions he also discussed were :Achromatopsia – or ‘colour-blind’ meaning that colour detection is not perfect – found in 1 in 8 males and 1 in 1000 females – sex linked on the X chromosome.‘Blind sight’ - where a person can still navigate without visual sensitivity.Charles Bonnet Syndrome – (which can be caused by macular degeneration) - whereby objects that are not there are imagined.Hemiopia – (which can be caused by a stroke) - whereby one half of the field of vision is defective. We also learned that babies have, from birth, an innate reflex which makes them look at the eyes of others. Eye defects in the young also seriously damage their learning ability and can often lead to dyslexia if left untreated. The prison population has a high incidence of dyslexia – suggesting a causal link. It was a fascinating lecture and Dr Frackieweicz was presented with a £100 donation from The Science Café together with a donation collected from the audience of a similar amount. Some of the audience also donated old spectacles that would be useful for his work in Kenya.