Measurement of the total optical angular momentum transfer in optical tweezers

We describe a way to determine the total angular momentum, both spin and orbital, transferred to a particle trapped in optical tweezers. As an example an LG02 mode of a laser beam with varying degrees of circular polarisation is used to trap and rotate an elongated particle with a well defined geometry. The method successfully estimates the total optical torque applied to the particle. For this technique, there is no need to measure the viscous drag on the particle, as it is an optical measurement. Therefore, knowledge of the particle's size and shape, as well as the fluid's viscosity, is not required.Comment: 7 pages, 3 figure

Speech rhythms and multiplexed oscillatory sensory coding in the human brain

Cortical oscillations are likely candidates for segmentation and coding of continuous speech. Here, we monitored continuous speech processing with magnetoencephalography (MEG) to unravel the principles of speech segmentation and coding. We demonstrate that speech entrains the phase of low-frequency (delta, theta) and the amplitude of high-frequency (gamma) oscillations in the auditory cortex. Phase entrainment is stronger in the right and amplitude entrainment is stronger in the left auditory cortex. Furthermore, edges in the speech envelope phase reset auditory cortex oscillations thereby enhancing their entrainment to speech. This mechanism adapts to the changing physical features of the speech envelope and enables efficient, stimulus-specific speech sampling. Finally, we show that within the auditory cortex, coupling between delta, theta, and gamma oscillations increases following speech edges. Importantly, all couplings (i.e., brain-speech and also within the cortex) attenuate for backward-presented speech, suggesting top-down control. We conclude that segmentation and coding of speech relies on a nested hierarchy of entrained cortical oscillations

On Time-sensitive Control Dependencies

We present efficient algorithms for time-sensitive control dependencies (CDs). If statement y is time-sensitively control dependent on statement x, then x decides not only whether y is executed but also how many timesteps after x. If y is not standard control dependent on x, but time-sensitively control dependent, then y will always be executed after x, but the execution time between x and y varies. This allows us to discover, e.g., timing leaks in security-critical software. We systematically develop properties and algorithms for time-sensitive CDs, as well as for nontermination-sensitive CDs. These work not only for standard control flow graphs (CFGs) but also for CFGs lacking a unique exit node (e.g., reactive systems). We show that Cytron’s efficient algorithm for dominance frontiers [10] can be generalized to allow efficient computation not just of classical CDs but also of time-sensitive and nontermination-sensitive CDs. We then use time-sensitive CDs and time-sensitive slicing to discover cache timing leaks in an AES implementation. Performance measurements demonstrate scalability of the approach

Celiac Disease: A Challenging Disease for Pharmaceutical Scientists

ABSTRACT: Celiac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of gluten-containing grains that affects ~1% of the white ethnic population. In the last decades, a rise in prevalence of CD has been observed that cannot be fully explained by improved diagnostics. Genetic predisposition greatly influences the susceptibility of individuals towards CD, though environmental factors also play a role. With no pharmacological treatments available, the only option to keep CD in remission is a strict and permanent exclusion of dietary gluten. Such a gluten-free diet is difficult to maintain because of gluten's omnipresence in food (e.g., additive in processed food). The development of adjuvant therapies which would permit the intake of small amounts of gluten would be desirable to improve the quality of life of patients on a gluten-free diet. Such therapies include gluten-degrading enzymes, polymeric binders, desensitizing vaccines, anti-inflammatory drugs, transglutaminase 2 inhibitors, and HLA-DQ2 blockers. However, many of these approaches pose pharmaceutical challenges with respect to drug formulation and stability, or application route and dosing interval. This perspective article discusses how pharmaceutical scientists may deal with these challenges and contribute to the implementation of novel therapeutic options for patients with C

The development of British First World War remembrance on the battlefield from 1914 to 1929

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.This thesis explores the role of Western Front battlefield landscapes between 1914 and 1929 in shaping memories of the First World War. It asks who visited the battlefields during the conflict, what impressions they formed, how they communicated these to others, and what influence these initial views had on post-war conceptions of the battlefield landscape. It explores how post-war visitors were guided to and through the battlefields, both by guidebooks and by tour operators, and how these sought to influence individual experiences. It examines how individual visitors sometimes went outside the framework of tours and published itineraries, and made their own attempts to connect with personal memories enshrined in the landscape. Section A of the thesis examines the itineraries offered by published guidebooks – firstly in the well-known Michelin guidebooks translated from the French, and secondly in the less widely-recognised British-authored guidebooks of the 1920s. Section B explores writing about the battlefields during the conflict itself, both through short articles in an Anglo-American periodical, and through full-length wartime books published by four influential authors – Rudyard Kipling, Edith Wharton, John Masefield and Harry Lauder. Section C turns to the experiences of individual travellers, and the extent to which they followed or departed from the itineraries and experiences to which these published sources directed them. The thesis argues that over the period 1914-29 there was a gradual but significant shift in what visitors focussed on within the battlefield landscape as it was tidied and reconstructed – a shift from battlefields themselves towards cemeteries and memorials. However, it argues that alongside this trend, visitors experienced a growing urgency, notwithstanding the clearing of battlefields, to find moments of reconnection with an authentic battlefield landscape which was seen as enshrining deeply personal memories. It shows that for veterans, this often involved connecting with sites which held real wartime memories, whilst for non-combatants it was much more about connecting with a landscape of the imagination. In particular, this thesis challenges the conventional narrative that the most important changes to landscape in the post-war period were the construction of cemeteries and memorials, arguing that just as important in the formation of cultural memory were the organic changes to the wider battlefield landscape