Evaluation of floral volatile patterns in the genus Narcissus using gas chromatography–coupled ion mobility spectrometry

Premise: Daffodils (Narcissus, Amaryllidaceae) are iconic ornamentals with a complex floral biology and many fragrant species; however, little is known about floral plant volatile organic compounds (pVOCs) across the genus and additional sampling is desirable. The present study investigates whether the floral scent of 20 species of Narcissus can be characterized using gas chromatography–coupled ion mobility spectrometry (GC–IMS), with the aim of building a comparative pVOC data set for ecological and evolutionary studies. Methods: We used a commercial GC–IMS equipped with an integrated in-line enrichment system for a fast, sensitive, and automated pVOC analysis. This facilitates qualitative and (semi)-quantitative measurements without sample preparation. Results: The GC–IMS provided detailed data on floral pVOCs in Narcissus with very short sampling times and without floral enclosure. A wide range of compounds was recorded and partially identified. The retrieved pVOC patterns showed a good agreement with published data, and five “chemotypes” were characterized as characteristic combinations of floral volatiles. Discussion: The GC–IMS setup can be applied to rapidly generate large amounts of pVOC data with high sensitivity and selectivity. The preliminary data on Narcissus obtained here indicate both considerable pVOC variability and a good correspondence of the pVOC patterns with infrageneric classification, supporting the hypothesis that floral scent could represent a considerable phylogenetic signal

Fostering communities of practice for improved food democracy : experiences and learning from South Africa

The highly concentrated formal agri-food sector holds enormous power in the governance of the food system in South Africa. Yet the concept of food democracy holds that all people should have an equal opportunity to participate in (re)shaping their food system. To contribute to decision making, however, stakeholders not only need access to knowledge about the food system, but should also be able to inform what is considered relevant knowledge. Communities of practice—groups of people who share a common interest or concern and who deepen their knowledge and expertise in this area by interacting on an ongoing basis—provide novel spaces for stakeholder involvement in food governance. This article sets out the process of establishing and maintaining a community of (food) practice in the Western Cape province of South Africa. Through participant observation, analysis of unpublished documents, as well as in depth interviews, the core elements of the community of practice are charted over its 3 yr history. The article demonstrates the informal and evolving nature of communities of practice as social learning structures that can gain credibility and potentially develop into more formal democratic institutions over.The DSI-NRF Centre of Excellence in Food Security, South Africahttps://wileyonlinelibrary.com/journal/uar2hj2022Political Science

MHC I Stabilizing Potential of Computer-Designed Octapeptides

Experimental results are presented for 180 in silico designed octapeptide sequences and their stabilizing effects on the major histocompatibility class I molecule H-2Kb. Peptide sequence design was accomplished by a combination of an ant colony optimization algorithm with artificial neural network classifiers. Experimental tests yielded nine H-2Kb stabilizing and 171 nonstabilizing peptides. 28 among the nonstabilizing octapeptides contain canonical motif residues known to be favorable for MHC I stabilization. For characterization of the area covered by stabilizing and non-stabilizing octapeptides in sequence space, we visualized the distribution of 100,603 octapeptides using a self-organizing map. The experimental results present evidence that the canonical sequence motives of the SYFPEITHI database on their own are insufficient for predicting MHC I protein stabilization

Handwriting performance in the absence of visual control in writer's cramp patients: Initial observations

BACKGROUND: The present study was aimed at investigating the writing parameters of writer's cramp patients and control subjects during handwriting of a test sentence in the absence of visual control. METHODS: Eight right-handed patients with writer's cramp and eight healthy volunteers as age-matched control subjects participated in the study. The experimental task consisted in writing a test sentence repeatedly for fifty times on a pressure-sensitive digital board. The subject did not have visual control on his handwriting. The writing performance was stored on a PC and analyzed off-line. RESULTS: During handwriting all patients developed a typical dystonic limb posture and reported an increase in muscular tension along the experimental session. The patients were significantly slower than the controls, with lower mean vertical pressure of the pen tip on the paper and they could not reach the endmost letter of the sentence in the given time window. No other handwriting parameter differences were found between the two groups. CONCLUSION: Our findings indicate that during writing in the absence of visual feedback writer's cramp patients are slower and could not reach the endmost letter of the test sentence, but their level of automatization is not impaired and writer's cramp handwriting parameters are similar to those of the controls except for even lower vertical pressure of the pen tip on the paper, which is probably due to a changed strategy in such experimental conditions

Mapping Obesogenic food environments in South Africa and Ghana: Correlations and contradictions

In sub-Saharan Africa, urbanisation and food systems change contribute to rapid dietary transitions promoting obesity. It is unclear to what extent these changes are mediated by neighbourhood food environments or other factors. This paper correlates neighbourhood food provision with household consumption and poverty in Khayelitsha, South Africa and Ahodwo, Ghana. Georeferenced survey data of food consumption and provision were classified by obesity risk and protection. Outlets were mapped, and density and distribution correlated with risk classe

Semi-convection in the ocean and in stars: A multi-scale analysis

Fluid stratified by gravitation can be subject to a number of instabilities which eventually lead to a flow that causes enhanced mixing and transport of heat. The special case where a destabilizing temperature gradient counteracts the action of a stabilizing gradient in molecular weight is of interest to astrophysics (inside stars and giant planets) and geophysics (lakes, oceans) as well as to some engineering applications. The detailed dynamics of such a system depend on the molecular diffusivities of heat, momentum, and solute as well as system parameters including the ratio of the two gradients to each other. Further important properties are the formation and merging of well-defined layers in the fluid which cannot be derived from linear stability analysis. Moreover, the physical processes operate on a vast range of length and time scales. This has made the case of semi-convection, where a mean temperature gradient destabilizes the stratification while at the same time the mean molecular gradient tends to stabilize it, a challenge to physical modelling and to numerical hydrodynamical simulation. During the MetStröm project the simulation codes ANTARES and MITgcm have been extended such that they can be used for the simulations of such flows. We present a comparison of effective diffusivities derived from direct numerical simulations. For both stars and the oceanic regimes, the Nusselt numbers (scaled diffusivities) follow similar relationships. Semi-convection quickly becomes inefficient, because the formation of layers limits vertical mixing. In contrast to the complementary saltfingering, these layers tend to damp instabilities so that effective diffusivities of salinity (concentration) are up to two orders of magnitudes smaller than in the former case

Entwicklung einer modularen Elektronik zum Aufbau von dezentralen Sensornetzwerken für akustische Prüfungen und Überwachungen

Diese Arbeit schildert den Entwicklungsprozess einer modularen Elektronik zum Auf- bau von dezentralen Sensornetzwerken für akustische Prüfungen und Überwachungen am „Deutschen Zentrum für Luft und Raumfahrt e.V.“. Die Arbeit umfasst eine Anforderungsanalyse, eine Konzeption mit anschließender praktischer Entwicklung eines Prototypen und umfassende praktische Tests der entwickelten Elektronik. Dabei werden Problemstellungen bezüglich der Schaltung von Ultraschallsignalen mit hohen Spannungsamplituden, der analogen und digitalen Signalübertragung und der geeigneten Spannungsversorgung bearbeitet. Der Aufbau und die Funktionsweise der Entwicklung werden ausführlich dokumentiert und visualisiert. Durch die Entwicklung eines dezentralen Sensornetzwerks für akustische Prüfungen und Über-wachungen erfolgt die Messdatenerfassung für eine Strukturüberwachung effizienter und es kön-nen neue Auswertealgorithmen entwickelt und getestet werden. This report describes the development of a modular electronic to build-up peripheral sensor-networks for sonic testing and monitoring at the German Aerospace Center. That includes a specification analysis, a conception followed up by a development of a prototype and extensive practical testing of the developed electronic. Though this different problems concerning the switching of ultrasonic high voltage signals, analog and digital signal transmission and suitable power supply are processed. The installa-tion and the operating mode of the development are documented and visualized in detail. Through the development of a sensor-network for sonic testing and monitoring recording of measured data is more effective and new analysis algorithms can be developed and tested

Co-production of knowledge in transdisciplinary communities of practice : experiences from food governance in South Africa

Communities of Practice are sites of social learning for the co-production of knowledge. Building on recent literature on Transdisciplinary Communities of Practice, this article reflects on the experiences of an emergent ‘Food Governance Community of Practice’ in South Africa that brings together multiple stakeholders to co-produce knowledge to inform local food policy and governance. Our results show the following lessons for managers and participants engaged in establishing similar ‘third spaces’ for knowledge co-production: 1) make inevitable power asymmetries explicit; 2) the identity of the group should not be built on a particular normative position but emerge from discursive processes and 3) create a balance between supporting peripheral learning and maintaining the specialist cutting edge discussions needed for co-production. Furthermore, the most beneficial legacy of a Community of Practice may not be the outputs in terms of the co-produced knowledge but the development of a cohesive group of stakeholders with a new shared way of knowing.The DSI-NRF Centre of Excellence in Food Security, South Africahttp://spp.oxfordjournals.org2022-12-07hj2022Political Science

The Berlin Brain-Computer Interface: Accurate performance from first-session in BCI-naive subjects

project develops a non-invasive BCI system whose key features are (1) the use of well-established motor competences as control paradigms, (2) high-dimensional features from multi-channel EEG and (3) advanced machine learning techniques. Spatiospectral changes of sensorimotor rhythms are used to discriminate imagined movements (left hand, right hand, foot). A previous feedback study ([1]) with 10 subjects provided preliminary evidence that the BBCI system can be operated at high accuracy for subjects with less than 5 prior BCI exposures. Here, we demonstrate in a group of 14 fully BCI-naïve subjects that 8/14 BCI novices can perform at>84 % accuracy in their very first BCI session, and a further 4 subjects>70%. Thus, 12/14 BCI-novices had significant above-chance level performances without any subject training even in the first session, as based on an optimized EEG analysis by advanced machine learning algorithms. I

Optimizing spatio-temporal filters for improving Brain-Computer Interfacing

Brain-Computer Interface (BCI) systems create a novel communication channel from the brain to an output device by bypassing conventional motor output pathways of nerves and muscles. Therefore they could provide a new communication and control option for paralyzed patients