Information flow through a model of the C. elegans klinotaxis circuit

Understanding how information about external stimuli is transformed into behavior is one of the central goals of neuroscience. Here we characterize the information flow through a complete sensorimotor circuit: from stimulus, to sensory neurons, to interneurons, to motor neurons, to muscles, to motion. Specifically, we apply a recently developed framework for quantifying information flow to a previously published ensemble of models of salt klinotaxis in the nematode worm C. elegans. The models are grounded in the neuroanatomy and currently known neurophysiology of the worm. The unknown model parameters were optimized to reproduce the worm's behavior. Information flow analysis reveals several key principles underlying how the models operate: (1) Interneuron class AIY is responsible for integrating information about positive and negative changes in concentration, and exhibits a strong left/right information asymmetry. (2) Gap junctions play a crucial role in the transfer of information responsible for the information symmetry observed in interneuron class AIZ. (3) Neck motor neuron class SMB implements an information gating mechanism that underlies the circuit's state-dependent response. (4) The neck carries non-uniform distribution about changes in concentration. Thus, not all directions of movement are equally informative. Each of these findings corresponds to an experimental prediction that could be tested in the worm to greatly refine our understanding of the neural circuit underlying klinotaxis. Information flow analysis also allows us to explore how information flow relates to underlying electrophysiology. Despite large variations in the neural parameters of individual circuits, the overall information flow architecture circuit is remarkably consistent across the ensemble, suggesting that information flow analysis captures general principles of operation for the klinotaxis circuit

Names of fungal species with the same epithet applied to different morphs: how to treat them

The abolition of the separate naming of different morphs of the same fungal species in 2011 will inevitably result in many name changes in some genera. The working practices commended here are intended to minimize one category of these changes, that which can arise as a consequence of an author using the epithet of an asexual morph when describing the sexual morph of the same species. We consider that name proposed for the sexual morph in such cases should be treated as a formal error for a new combination and not as a new species, and so be corrected. This is interpreted as applying even where the author indicated that a new species was being described and designated a type. We argue that those formalities were a result of the requirements of the rules then in force, as the author recognized that a morph of a named species was being described, and not a new hitherto unnamed species was being reported - but was barred from making a new combination so used the same epithet for the new morph name instead. Where a type with the sexual morph was designated for the sexual morph, under this interpretation that no longer has nomenclatural status, the type being that of the basionym. The material for the sexual morph indicated as a type, would be available for designation as an epitype, though a modern sequenced sample with both sexual and asexual morphs would be more informative as an epitype in many cases. A proposal to regularize the working practice commended here, and also the converse situation where the sexual morph typified name is the earlier, will be made to the 2017 Shenzhen Congress

Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy

We studied the interaction between phototrophic and chemolithoautotrophic sulphide-oxidizing microorganisms in natural microbial mats forming in sulphidic streams. The structure of these mats varied between two end-members: one characterized by a layer dominated by large sulphur-oxidizing bacteria (SOB; mostly Beggiatoa-like) on top of a cyanobacterial layer (B/C mats) and the other with an inverted structure (C/B mats). C/B mats formed where the availability of oxygen from the water column was limited (<5 mu M). Aerobic chemolithotrophic activity of the SOB depended entirely on oxygen produced locally by cyanobacteria during high light conditions. In contrast, B/C mats formed at locations where oxygen in the water column was comparatively abundant (445 mu M) and continuously present. Here SOB were independent of the photosynthetic activity of cyanobacteria and outcompeted the cyanobacteria in the uppermost layer of the mat where energy sources for both functional groups were concentrated. Outcompetition of photosynthetic microbes in the presence of light was facilitated by the decoupling of aerobic chemolithotrophy and oxygenic phototrophy. Remarkably, the B/C mats conserved much less energy than the C/B mats, although similar amounts of light and chemical energy were available. Thus ecosystems do not necessarily develop towards optimal energy usage. Our data suggest that, when two independent sources of energy are available, the structure and activity of microbial communities is primarily determined by the continuous rather than the intermittent energy source, even if the time-integrated energy flux of the intermittent energy source is greater

Complications après hystérectomie pour cancers gynécologiques : Laparoscopie vs Laparotomie.

Objectif : Comparer les hystérectomies réalisées par laparoscopie à celles accomplies par laparotomie pour des pathologies gynécologiques malignes. Méthode : Etude basée sur 169 hystérectomies effectuées pour cancer de l'endomètre, du col ou de l'ovaire, pratiquées dans le service de gynécologie de la Maternité du CHUV de janvier 2002 à décembre 2009 sur des femmes âgées de 28 à 91 ans. Le but est de comparer deux différentes voies d'abord chirurgicales qui sont la laparotomie et la laparoscopie en terme de durée d'hospitalisation, d'indications, de complications per et post opératoires mineures et majeures et de nécessité de reprise ou d'une ré-hospitalisation. Résultats: Cette étude compte 169 patientes, dont 126 hystérectomies réalisées par laparotomie et 43 accomplies par laparoscopie. Les deux groupes sont similaires en terme d'âge (âge moyen : 63ans), d'indice de masse corporelle (26 vs 25) et de parité (1.5 enfants). Le temps opératoire est semblable entre les deux groupes (211 vs 219 minutes). Des hémorragies (pertes sanguines de plus de 1000ml) surviennent dans 24.6% des hystérectomies par laparotomie et dans 11.63% des hystérectomies par laparoscopie. Il existe une différence statistiquement significative entre la nécessité d'une transfusion peropératoire et les deux différentes voie d'abord (p=0.045). Une transfusion peropératoire a été nécessaire dans 13.22% des laparotomies contre seulement 2.33% des laparoscopies. La durée d'hospitalisation est significativement plus longue pour les patientes ayant subi une hystérectomie par laparotomie (12 vs 6 jours; p&lt;0.001). Les complications peropératoires et postopératoires mineures dépendent de manière significative de la voie d'abord (p=0.01 ; p= 0.025). On observe des complications peropératoires dans 31.75% des laparotomies et dans 11.63% des laparoscopies. Les complications postopératoires mineures sont observées dans 28.57% des laparotomies et dans 11.63% des laparoscopies. Dans 7.14% des laparotomies on observe une complications postopératoire majeure et aucune de sont apparues lors d'hystérectomie par laparoscopie. La nécessité de reprise, de ré-opération ou de ré-hospitalisation n'est statistiquement pas différente entre la laparoscopie et la laparotomie. Conclusion : On observe un avantage significatif en faveur de l'hystérectomie par laparoscopie avec une réduction de la durée d'hospitalisation, ainsi que des complications peropératoires et postopératoires mineures et majeures, moins importantes

Postmortem tissue distribution of morphine and its metabolites in a series of heroin related deaths

The abuse of heroin (diamorphine) and heroin deaths are growing around the world. The interpretation of the toxicological results from suspected heroin deaths is notoriously difficult especially in cases where there may be limited samples. In order to help forensic practitioners with heroin interpretation we determined the concentration of morphine (M), morphine‐3‐glucuronide (M3G) and morphine‐6‐glucuronide (M6G) in blood (femoral and cardiac), brain (thalamus), liver (deep right lobe), bone marrow (sternum), skeletal muscle (psoas) and vitreous humor in 44 heroin related deaths. The presence of 6‐monoacetylmorphine (6‐MAM) in any of the postmortem samples was used as confirmation of heroin use. Quantitation was carried out using a validated LC‐MS/MS method with solid phase extraction. We also determined the presence of papaverine, noscapine and codeine in the samples, substances often found in illicit heroin and that may help determine illicit heroin use. The results of this study show that vitreous is the best sample to detect 6‐MAM (100% of cases), and thus heroin use. The results of the M, M3G and M6G quantitation in this study allow a degree of interpretation when samples are limited. However in some cases it may not be possible to determine heroin/morphine use as in 4 cases in muscle (3 cases in bone marrow) no morphine, morphine‐3‐glucuronide or morphine‐6‐glucuronide was detected, even though they were detected in other case samples. As always postmortem cases of suspected morphine/heroin intoxication should be interpreted with care and with as much case knowledge as possible

The provision of education and training for healthcare professionals through the medium of the internet

This paper describes a new initiative to provide Internet based courses to student and professional occupational therapists in four centres in the UK, Belgium the Netherlands and Sweden. The basis of this collaborative Occupational Therapy Internet School (OTIS) is the concept of the “Virtual College”. This comprises the design and implementation of a sophisticated Internet-based system through which courses can be managed, prepared and delivered online in an effective fashion, and where students can communicate both with the staff and their peers. The aim is to support and facilitate the whole range of educational activities within a remote electronic environment. A major feature of the course organisation is the adoption of a problem-based approach in which students will collaborate internationally to propose effective intervention in given case study scenarios. The paper outlines the rationale for OTIS, the content and structure of the courseware, the technical specification of the system and evaluation criteria. In addition to the more conventional web-based learning facilities generally offered, a number of agent-based approaches are being adopted to assist in the management of the course by ensuring the proper delivery of course materials and to assist the functioning of project groups. </p

Multinational lessons from local and regional economic development agencies

This paper discusses the commonalities and differences in local and regional economic development (LRED) across England, Northern Ireland, Australia and the US. The focus is on four themes: the institutional characteristics of the respondents; governance, partners and partnerships; the objectives, regional capacity building and business service activities of responding agencies; and the self-assessment of effectiveness by LRED organisations. Our analysis is based on a survey of LRED agencies in the above-noted countries using a common questionnaire that was slightly adapted for each study area. Using logistic regression, we identify the practices and strategies of local and regional economic development agencies that are associated with higher levels of effectiveness. When all participating nations’ LRED organisations are jointly evaluated, several practices emerge as being positively related to agency performance including being actively involved in industrial estates, labour training and recruitment, marketing the agency’s region to international markets, and promoting industry clusters. Also showing as being positively related to performance are variables identifying whether or not the agency subsidized relocation costs for new businesses, helps local companies access venture capital, engages in education and training programs targeted at youths, and enhances networking opportunities for local business people. Interestingly, we found statistically significant negative relationships between agency effectiveness and engaging in tourism promotion activities, training minority groups, and conducting target industry studies, though this may reflect a correlation between certain activities and problematic economic environments. Though our research methodology of relying on self-assessed performance measures does not allow us to draw sweeping conclusions, we are confident that these findings provide a beginning for identifying a set of best practices that are appropriate for LRED organisations in a multinational setting.

Excitons in Electrostatic Traps

We consider in-plane electrostatic traps for indirect excitons in coupled quantum wells, where the traps are formed by a laterally modulated gate voltage. An intrinsic obstacle for exciton confinement in electrostatic traps is an in-plane electric field that can lead to exciton dissociation. We propose a design to suppress the in-plane electric field and, at the same time, to effectively confine excitons in the electrostatic traps. We present calculations for various classes of electrostatic traps and experimental proof of principle for trapping of indirect excitons in electrostatic traps.Comment: 4 pages, 3 figure

Perfection of materials technology for producing improved Gunn-effect devices Interim scientific report

Chemical vapor deposition of epitaxial gallium arsenid