Low-Noise Amplification of a Continuous Variable Quantum State

We present an experimental realization of a low-noise, phase-insensitive optical amplifier using a four-wave mixing interaction in hot Rb vapor. Performance near the quantum limit for a range of amplifier gains, including near unity, can be achieved. Such low-noise amplifiers are essential for so-called quantum cloning machines and are useful in quantum information protocols. We demonstrate that amplification and ``cloning'' of one half of a two-mode squeezed state is possible while preserving entanglement.Comment: To appear in Physical Review Letters July 3rd. 4 pages, 4 figure

Point-wise mutual information-based video segmentation with high temporal consistency

In this paper, we tackle the problem of temporally consistent boundary detection and hierarchical segmentation in videos. While finding the best high-level reasoning of region assignments in videos is the focus of much recent research, temporal consistency in boundary detection has so far only rarely been tackled. We argue that temporally consistent boundaries are a key component to temporally consistent region assignment. The proposed method is based on the point-wise mutual information (PMI) of spatio-temporal voxels. Temporal consistency is established by an evaluation of PMI-based point affinities in the spectral domain over space and time. Thus, the proposed method is independent of any optical flow computation or previously learned motion models. The proposed low-level video segmentation method outperforms the learning-based state of the art in terms of standard region metrics

Anti-NMDA-R encephalitis: an encephalitis lerthargica-like illness

Posters: no. P14A girl of 3 years and 9 months with a 3-day history of fever and upper respiratory tract infection (URTI) was admitted with a generalised tonic-clonic convulsion, and delirium with screaming, non-sense talking, and agitation. For the first week after admission, she was lethargic with fluctuating awareness and mutism during the day but poor sleep at night. Workup for acute encephalopathy including autoimmune, infective, toxicology, metabolic and vasculitic screening showed negative findings. Erythrocyte sedimentation rate was markedly elevated and ...published_or_final_versionThe 1st Hong Kong Neurological Congress cum 22nd Annual Scientific Meeting of the Hong Kong Neurological Society, Hong Kong, 6-8 November 2009. In Hong Kong Medical Journal, 2009, v. 15 n. 6, suppl. 7, p. 47, abstract P1

Towards a design process for computer-aided biomimetics

Computer-Aided Biomimetics (CAB) tools aim to support the integration of relevant biological knowledge into biomimetic problem-solving processes. Specific steps of biomimetic processes that require support include the identification, selection and abstraction of relevant biological analogies. Existing CAB tools usually aim to support these steps by describing biological systems in terms of functions, although engineering functions do not map naturally to biological functions. Consequentially, the resulting static, functional view provides an incomplete understanding of biological processes, which are dynamic, cyclic and self-organizing. This paper proposes an alternative approach that revolves around the concept of trade-offs. The aim is to include the biological context, such as environmental characteristics, that may provide information crucial to the transfer of biological information to an engineering application. The proposed design process is exemplified by an illustrative case study

Bariatric surgery in morbidly obese insulin resistant humans normalises insulin signalling but not insulin-stimulated glucose disposal.

This is the final published version. Available from PLoS via the DOI in this record.All relevant data are available from Figshare, under the DOI http://dx.doi. org/10.6084/m9.figshare.1292883.AIMS: Weight-loss after bariatric surgery improves insulin sensitivity, but the underlying molecular mechanism is not clear. To ascertain the effect of bariatric surgery on insulin signalling, we examined glucose disposal and Akt activation in morbidly obese volunteers before and after Roux-en-Y gastric bypass surgery (RYGB), and compared this to lean volunteers. MATERIALS AND METHODS: The hyperinsulinaemic euglycaemic clamp, at five infusion rates, was used to determine glucose disposal rates (GDR) in eight morbidly obese (body mass index, BMI=47.3 ± 2.2 kg/m(2)) patients, before and after RYGB, and in eight lean volunteers (BMI=20.7 ± 0.7 kg/m2). Biopsies of brachioradialis muscle, taken at fasting and insulin concentrations that induced half-maximal (GDR50) and maximal (GDR100) GDR in each subject, were used to examine the phosphorylation of Akt-Thr308, Akt-473, and pras40, in vivo biomarkers for Akt activity. RESULTS: Pre-operatively, insulin-stimulated GDR was lower in the obese compared to the lean individuals (P<0.001). Weight-loss of 29.9 ± 4 kg after surgery significantly improved GDR50 (P=0.004) but not GDR100 (P=0.3). These subjects still remained significantly more insulin resistant than the lean individuals (p<0.001). Weight loss increased insulin-stimulated skeletal muscle Akt-Thr308 and Akt-Ser473 phosphorylation, P=0.02 and P=0.03 respectively (MANCOVA), and Akt activity towards the substrate PRAS40 (P=0.003, MANCOVA), and in contrast to GDR, were fully normalised after the surgery (obese vs lean, P=0.6, P=0.35, P=0.46, respectively). CONCLUSIONS: Our data show that although Akt activity substantially improved after surgery, it did not lead to a full restoration of insulin-stimulated glucose disposal. This suggests that a major defect downstream of, or parallel to, Akt signalling remains after significant weight-loss.Diabetes Research and Wellness FoundatioMedical Research Council (MRC)Astra Zenec

Good Vibrations : The evolution of whisking in small mammals

Special Issue: Extreme Anatomy: Living Beyond the Edge. January 2020Abstract While most mammals have whiskers, some tactile specialists - mainly small, nocturnal and arboreal species - can actively move their whiskers in a symmetrical, cyclic movement called whisking. Whisking enables mammals to rapidly, tactually scan their environment in order to efficiently guide locomotion and foraging in complex habitats. The muscle architecture that enables whisking is preserved from marsupials to primates, prompting researchers to suggest that a common ancestor might have had moveable whiskers. Studying the evolution of whisker touch sensing is difficult, and we suggest that measuring an aspect of skull morphology that correlates with whisking would enable comparisons between extinct and extant mammals. We find that whisking mammals have larger infraorbital foramen (IOF) areas, which indicates larger infraorbital nerves and an increase in sensory acuity. While this relationship is quite variable and IOF area cannot be used to solely predict the presence of whisking, whisking mammals all have large IOF areas. Generally, this pattern holds true regardless of an animal's substrate preferences or activity patterns. Data from fossil mammals and ancestral character state reconstruction and tracing techniques for extant mammals suggest that whisking is not the ancestral state for therian mammals. Instead, whisking appears to have evolved independently as many as seven times across the clades Marsupialia, Afrosoricida, Eulipotyphla and Rodentia, with Xenarthra the only placental superordinal clade lacking whisking species. However, the term whisking only captures symmetrical and rhythmic movements of the whiskers, rather than all possible whisker movements, and early mammals may still have had moveable whiskers. This article is protected by copyright. All rights reserved.Peer reviewe

Socially sensitive lactation: Exploring the social context of breastfeeding

Many women report difficulties with breastfeeding and do not maintain the practice for as long as intended. Although psychologists and other researchers have explored some of the difficulties they experience, fuller exploration of the relational contexts in which breastfeeding takes place is warranted to enable more in-depth analysis of the challenges these pose for breastfeeding women. The present paper is based on qualitative data collected from 22 first-time breastfeeding mothers through two phases of interviews and audio-diaries which explored how the participants experienced their relationships with significant others and the wider social context of breastfeeding in the first five weeks postpartum. Using a thematic analysis informed by symbolic interactionism, we develop the overarching theme of ‘Practising socially sensitive lactation’ which captures how participants felt the need to manage tensions between breastfeeding and their perceptions of the needs, expectations and comfort of others. We argue that breastfeeding remains a problematic social act, despite its agreed importance for child health. Whilst acknowledging the limitations of our sample and analytic approach, we suggest ways in which perinatal and public health interventions can take more effective account of the social challenges of breastfeeding in order to facilitate the health and psychological well-being of mothers and their infants