Species recognition by the sequence of discharge intervals in weakly electric fishes of the genus Campylomormyrus (Mormyridae, Teleostei)

In two Campylomormyrus species, tamandua and rhynchophorus from Central Africa, the electric organ discharge (EOD) activity was studied during the nocturnal activity phase in the laboratory. Both species have a pulse-type EOD of less than 200 μs duration and similar waveform; the sequence of inter-discharge intervals, however, differed characteristically: C. tamandua displayed a 'micro-pattern' encompassing nearly the whole range of intervals in a sequence of only three intervals (long-intermediate-short), while in C. rhynchophorus adjacent intervals tended to be more similar in duration. Four C. rhynchophorus and five C. tamandua were tested for their preference of conspecific pulse sequences rather than those of the other species, respectively, in playback experiments. These were performed in a T-maze paradigm such that two pulse patterns, one from each species, were simultaneously presented via two electric fish dipole models. Two pulse sequences recorded from different individuals were used to represent each species; the natural EOD waveform was replaced by a square-wave pulse of approximately natural duration. The pattern pairings and the sequence of stimulus patterns followed a randomized blocks design. Each of the four C. rhynchophorus had significantly higher preference scores for the conspecific pulse patterns than for those of C. tamandua, while in C. tamandua no such discrimination was observed. It is suggested that the juvenile C. tamandua used would probably have joined mixed-species schools as reported to exist in the wild, while this appears unlikely in the more mature C. rhynchophorus. One of the functions of the inter-discharge interval code of communication in mormyrids is species recognition although this may be seen only in sufficiently mature fish

Occupational medical prophylaxis for the musculoskeletal system: A function-oriented system for physical examination of the locomotor system in occupational medicine (fokus(C))

Occupational physicians are very often confronted with questions as to the fitness of the postural and locomotor systems, especially the spinal column. Occupational medical assessment and advice can be required by patients with acute symptoms, at routine check-ups, by persons who have problems doing certain jobs, and for expert medical reports as to the fitness of persons with chronic disorders or after operations. Therefore, for occupational medical purposes a physical examination must aim primarily to investigate functions and not structures or radiologic evidence. The physical examination should be structured systematically and according to regions of the body and, together with a specific (pain) anamnesis should provide a basis for the medical assessment

Software for non-parametric image registration of 2-photon imaging data

Functional 2-photon microscopy is a key technology for imaging neuronal activity. The recorded image sequences, however, can contain non-rigid movement artifacts which requires high-accuracy movement correction. Variational optical flow (OF) estimation is a group of methods for motion analysis with established performance in many computer vision areas. However, it has yet to be adapted to the statistics of 2-photon neuroimaging data. In this work, we present the motion compensation method Flow-Registration that outperforms previous alignment tools and allows to align and reconstruct even low signal-to-noise ratio 2-photon imaging data and is able to compensate high-divergence displacements during local drug injections. The method is based on statistics of such data and integrates previous advances in variational OF estimation. Our method is available as an easy-to-use ImageJ/FIJI plugin as well as a MATLAB toolbox with modular, object oriented file IO, native multi-channel support and compatibility with existing 2-photon

Imaging Ca2+ Concentration and pH in Nanopores/Channels of Protein Crystals

Protein crystals are nanoporous materials. Despite this important characteristic, little is known about the conditions in the pores, also called channels. Here, we describe a method to study the calcium concentration and pH in the nanopores of thaumatin and lysozyme crystals. We load the crystal nanopores with fluorescent indicators and then perfuse the crystals with solutions of different calcium concentrations and pH while reading out the crystal’s fluorescence intensity with confocal microscopy. By calibrating the fluorescence signal, we can determine the calcium concentration and pH in the nanopores. For the pH in thaumatin nanopores measured with the ratiometric pH sensor SNARF-1, we find a −0.7 pH shift compared to the bath pH corresponding to a fivefold higher proton concentration. This is similar to the −0.3 pH shift found in lysozyme nanopores. With single-wavelength probes, we find that the calcium concentration in thaumatin crystal nanopores is the same as in the bath, whereas it is 0.24 times lower in lysozyme nanopores. Summarizing, our experiments show that calcium concentration and pH in the nanopores of protein crystals can deviate significantly from that in the bath. In general, the described method can be applied for testing a wide range of ion or small-molecule concentrations in transparent nanoporous materials not only with ratiometric but also with single wavelength fluorescent indicators

Complementary Ca2+ Activity of Sensory Activated and Suppressed Layer 6 Corticothalamic Neurons Reflects Behavioral State

Layer 6 (L6) corticothalamic neurons project to thalamus, where they are thought to regulate sensory information transmission to cortex. However, the activity of these neurons during different behavioral states has not been described. Here, we imaged calcium changes in visual cortex L6 primary corticothalamic neurons with two-photon microscopy in head-fixed mice in response to passive viewing during a range of behavioral states, from locomotion to sleep. In addition to a substantial fraction of quiet neurons, we found sensory-activated and suppressed neurons, comprising two functionally distinct L6 feedback channels. Quiet neurons could be dynamically recruited to one or another functional channel, and the opposite, functional neurons could become quiet under different stimulation conditions or behavior states. The state dependence of neuronal activity was heterogeneous with respect to locomotion or level of alertness, although the average activity was largest during highest vigilance within populations of functional neurons. Interestingly, complementary activity of these distinct populations kept the overall corticothalamic feedback relatively constant during any given behavioral state. Thereby, in addition to sensory and non-sensory information, a constant activity level characteristic of behavioral state is conveyed to thalamus, where it can regulate signal transmission from the periphery to cortex

Enabling Acoustic Audience Feedback in Large Virtual Events

The COVID-19 pandemic shifted many events in our daily lives into the virtual domain. While virtual conference systems provide an alternative to physical meetings, larger events require a muted audience to avoid an accumulation of background noise and distorted audio. However, performing artists strongly rely on the feedback of their audience. We propose a concept for a virtual audience framework which supports all participants with the ambience of a real audience. Audience feedback is collected locally, allowing users to express enthusiasm or discontent by selecting means such as clapping, whistling, booing, and laughter. This feedback is sent as abstract information to a virtual audience server. We broadcast the combined virtual audience feedback information to all participants, which can be synthesized as a single acoustic feedback by the client. The synthesis can be done by turning the collective audience feedback into a prompt that is fed to state-of-the-art models such as AudioGen. This way, each user hears a single acoustic feedback sound of the entire virtual event, without requiring to unmute or risk hearing distorted, unsynchronized feedback.Comment: 4 pages, 2 figure

Mid-Atlantic expedition 2003/2004 : research vessel Meteor, cruise No. M60 ; 11. November 2003 – 15. April 2004

Die Meteor-Reise 60 besteht aus 5 Fahrtabschnitten im subtropischen Wirbel des Nordatlantiks von den Azoren bzw. Madeira bis zum tropischen Westatlantik. Fahrtabschnitt 1 konzentriert sich auf die Ökologie und Biogeochemie von sogenannten „Seamounts“ im östlichen Atlantik im Rahmen eines EU-Projektes; Fahrtabschnitt 2 umfasst, in Zusammenarbeit mit französischen Kollegen, detailierte seismische und geophysikalische Untersuchungen eines aktiven Segments des Mittelatlantischen Rückens; Fahrtabschnitt 3 ist eine multidisziplinäre (geologisch, biologisch und chemisch) Untersuchung über die Auswirkungen der hydrothermalen Zirkulation am Mittelatlantischen Rücken im Rahmen eines DFG-Schwerpunkt-programms; Fahrtabschnitt 4 ist einer physikalisch-ozeanographische Studie der langfristigen Variation der thermohalien Zirkulation in westlichen Becken des Atlantiks im Kontext des BMBF-CLIVAR programms gewidmet; und Fahrtabschnitt 5 schließlich, ist eine multidisziplinäre (chemisch/biologisch) Untersuchung über die CO2-Aufnahme und die biologische Pumpe in der Wassersäule des nordatlantischen Subtropenwirbels (DFG-Sonderforschungsbereich 460). Der erste Fahrtabschnitt der Reise M 60 dient der physikalischen, biogeochemischen und biologischen Probengewinnung im Rahmen des EU- Projektes OASIS (OceAnic Seamounts: an Integrated Study). OASIS ist ein interdisziplinäres Projekt mit 9 Partnern aus 5 europäischen Ländern und untersucht die funktionale Charakteristik von Seamount-Ökosystemen. Basierend auf 2 Fallstudien werden die Prozesse, die Seamount-Ökosysteme charakterisieren, und ihre Einflüsse auf den umgebenden Ozean beschrieben. Die wissenschaftlichen Ergebnisse, zusammengeführt in einem konzeptionellen Ökosystemmodell, werden Ausgangsbasis für die Entwicklung von generellen und ortspezifischen Managementplänen sein. Das primäre Ziel von OASIS, eine holistische Erfassung von Seamount-Ökosystemen, wird durch die Integration folgender Sachgebiete erreicht: a) Identifikation und Beschreibung der physikalischen Einflußkräfte auf Seamount-Ökosysteme b) Erfassung der Herkunft, Qualität und Dynamik partikulärer organischer Substanz in der Wassersäule und an der Sedimentoberfläche c) Beschreibung von Aspekten der Biodiversität und Ökologie von Seamount-Lebensgemeinschaften und Erfassung ihrer Dynamik und Produktionsmechanismen d) Modellierung der trophischen Ökologie von Seamount-Ökosystemen e) Anwendung der wissenschaftlichen Ergebnisse auf den Naturschutz. Ein weiteres Ziel der Fahrt ist die Erprobung eines neu entwickelten Drucklabors zur Untersuchung von Tiefseeorganismen unter in situ-Druckbdingenungen von bis zu 500 bar.The Meteor 60 expedition is comprised of 5 legs covering the sub-tropical gyre of the North Atlantic from the Azores and Madeira to the tropical western Atlantic. Leg 1 focuses on the ecology and biogeochemistry of seamounts in the eastern Atlantic in the context of an EU program; Leg 2 comprises a detailed seismic and geophysical investigation of a propagating ridge segment at the Mid-Atlantic Ridge in cooperation with French scientists; Leg 3 is a multidisciplinary (geological, biological and chemical) investigation of the effects of hydrothermal circulation at the Mid-Atlantic ridge in support of a DFG Special Priority Program; Leg 4 is a physical oceanographic study of long-term variation of the thermohaline circulation in the western basin of the Atlantic in the context of the BMBF-CLIVAR program; and Leg 5 is a multidisciplinary (chemical/biological) investigation of CO2 uptake and the biological pump in the water column of the North Atlantic sub-tropical gyre (DFG Special Research Area 460). The first leg of cruise M 60 aims at physical, biogeochemical and biological sampling in the framework of the EU project OASIS (OceAnic Seamounts: an Integrated Study). OASIS is an interdisciplinary project and comprises 9 partners from 5 European countries. The project studies the functional characteristics of seamount ecosystems. Based on two case studies, OASIS will yield an advanced mechanistic understanding of the processes characterizing seamount ecosystems, and their influence on the surrounding ocean. The scientific knowledge gained, condensed in a conceptual ecosystem model, will be applied to outline a model management plan as well as site-specific management plans for the seamounts investigated The primary goal of OASIS, to provide a holistic, integrated assessment of seamount ecology, will be achieved by addressing the following main objectives: a) To identify and describe the physical forcing mechanisms effecting seamount systems. b) To assess the origin, quality and dynamics of particulate organic material within the water column and surface sediment at seamounts. c) To describe aspects of the biodiversity and the ecology of seamount biota, to assess their dynamics and the maintenance of their production. d) Modelling the trophic ecology of seamount ecosystems. e) Application of scientific knowledge to practical conservation. A further goal of the cruise will be to test a newly developed hyperbaric laboratory which is designed to study deep-sea organisms under in situ pressure