Spatial vision in insects is facilitated by shaping the dynamics of visual input through behavioral action

Egelhaaf M, Boeddeker N, Kern R, Kurtz R, Lindemann JP. Spatial vision in insects is facilitated by shaping the dynamics of visual input through behavioral action. Frontiers in Neural Circuits. 2012;6:108.Insects such as flies or bees, with their miniature brains, are able to control highly aerobatic flight maneuvres and to solve spatial vision tasks, such as avoiding collisions with obstacles, landing on objects, or even localizing a previously learnt inconspicuous goal on the basis of environmental cues. With regard to solving such spatial tasks, these insects still outperform man-made autonomous flying systems. To accomplish their extraordinary performance, flies and bees have been shown by their characteristic behavioral actions to actively shape the dynamics of the image flow on their eyes ("optic flow"). The neural processing of information about the spatial layout of the environment is greatly facilitated by segregating the rotational from the translational optic flow component through a saccadic flight and gaze strategy. This active vision strategy thus enables the nervous system to solve apparently complex spatial vision tasks in a particularly efficient and parsimonious way. The key idea of this review is that biological agents, such as flies or bees, acquire at least part of their strength as autonomous systems through active interactions with their environment and not by simply processing passively gained information about the world. These agent-environment interactions lead to adaptive behavior in surroundings of a wide range of complexity. Animals with even tiny brains, such as insects, are capable of performing extraordinarily well in their behavioral contexts by making optimal use of the closed action-perception loop. Model simulations and robotic implementations show that the smart biological mechanisms of motion computation and visually-guided flight control might be helpful to find technical solutions, for example, when designing micro air vehicles carrying a miniaturized, low-weight on-board processor

Effects of team leaders' position in cardiopulmonary resuscitation teams on leadership behavior and team performance: A prospective randomized interventional cross-over simulation-based trial.

BACKGROUND Leadership is an important performance factor in resuscitation teams. Medical guidelines for cardiopulmonary resuscitation (CPR) advise team leaders to keep hands off patients. There is little evidence for this recommendation that is based purely on observational data. Accordingly, the aim of this trial was to investigate the effect of leaders' position during CPR on leadership behavior and team performance. METHOD This is a prospective randomized interventional crossover simulation-based single center trial. Teams of 3 to 4 physicians each, representing a rapid response team, were confronted with a simulated cardiac arrest. Team leaders were randomly assigned and assigned team leaders were 1:1 randomized to 2 leadership positions: position at the patient's head; and hands-off position. Data analysis was performed from video-recordings. All utterances during the first 4 minutes of CPR were transcribed and coded based on a modified "Leadership Description Questionnaire." The primary endpoint was the number of leadership statements. Secondary outcomes included CPR related performance markers like hands-on time and chest compression rate, and the behavioral related endpoints Decision Making, Error Detection, and Situational Awareness. RESULTS Data from 40 teams (143 participants) was analyzed. Leaders in hands-off position made more leadership statements (28 ± 8 vs 23 ± 8; P <.01) and contributed more to their team's leadership (59 ± 13% vs 50 ± 17%; P = .01) than leaders in the head position. Leaders' position had no significant effect on their teams' CPR performance, Decision Making, and Error Detection. Increased numbers of leadership statements lead to improved hands-on time ( R = 0.28; 95% confidence interval 0.05-0.48; P = .02). CONCLUSIONS Team leaders in a hands-off position made more leadership statements and contributed more to their teams' leadership during CPR than team leaders actively involved in the head position. However, team leaders' position had no effect on their teams' CPR performance

The salience of comparison standards and the activation of social norms: consequences for judgments of happiness and their communications

'Zwei Untersuchungen wurden durchgeführt, in denen Berichte über das eigene subjektive Wohlbefinden beeinflußt werden a) durch die Augenfälligkeit eines Vergleichsstandards und b) durch die Aktivierung einer sozialen Norm im Kontext der Urteilsabgabe. Wir fanden, daß sich die Versuchspersonen in Anwesenheit einer anderen Person, der es vergleichsweise schlechter ging, als glücklicher einschätzten. Dieser Kontrasteffekt trat verstärkt auf, wenn die Aufmerksamkeit der Vpn beim Ausfüllen des Fragebogens durch ein natürliches Sitzarrangement auf die Vergleichsperson gerichtet war. Die Ergebnisse des zweiten Experiments, in dem die Darbietungsform der Befragung (anonym vs. offen) und der offensichtliche Gesundheitszustand der Vergleichsperson (körperbehindert oder nicht) variiert wurde, zeigen, daß solche vergleichende Urteile nicht geäußert werden, wenn die Antworten dem körperbehinderten Versuchsteilnehmer gegenüber offen geäußert werden müssen. Zusammengenommen machen beide Untersuchungen deutlich, daß kognitive und kommunikative Prozesse gleichermaßen beachtet werden müssen, um die Determinanten von Urteilen des subjektiven Wohlbefindens zu verstehen.' (Autorenreferat)'Two studies were conducted in which subjects' reports of their own happiness were influenced a) by the salience of comparison standards and b) by the social norm that was activated in the context of communicating those judgments. It was found that the presence of another person who was relatively worse off led to more positive judgments of the subjects' own happiness. This contrast effect was increased when subjects' attention was directed toward the comparison person by a natural seating arrangement at the time the questionnaire had to be filled out. The results of the second study in which the mode of administration (private vs. public) and the apparent state of health of the comparison person were varied (physically handicapped or not), show that such contrastive judgments may not be uttered when the judgment has to be reported to the handicapped confederate. Taken together, these studies demonstrate how both cognitive and communicative mechanisms must be taken into account to understand the determinants of judgments of subjective well-being.' (author's abstract

Novel mRNA-specific effects of ribosome drop-off on translation rate and polysome profile

IS and MCR were supported by the Biotechnology and Biological Sciences Research Council (BBSRC) (http://www.bbsrc.ac.uk) BB/N017161/1. IS was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) (http://www.bbsrc.ac.uk) BB/I020926/1. PB and MCR were supported by the Scottish Universities Life Sciences Alliance (SULSA) (http://www.sulsa.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Upper bounds for the secure key rate of decoy state quantum key distribution

The use of decoy states in quantum key distribution (QKD) has provided a method for substantially increasing the secret key rate and distance that can be covered by QKD protocols with practical signals. The security analysis of these schemes, however, leaves open the possibility that the development of better proof techniques, or better classical post-processing methods, might further improve their performance in realistic scenarios. In this paper, we derive upper bounds on the secure key rate for decoy state QKD. These bounds are based basically only on the classical correlations established by the legitimate users during the quantum communication phase of the protocol. The only assumption about the possible post-processing methods is that double click events are randomly assigned to single click events. Further we consider only secure key rates based on the uncalibrated device scenario which assigns imperfections such as detection inefficiency to the eavesdropper. Our analysis relies on two preconditions for secure two-way and one-way QKD: The legitimate users need to prove that there exists no separable state (in the case of two-way QKD), or that there exists no quantum state having a symmetric extension (one-way QKD), that is compatible with the available measurements results. Both criteria have been previously applied to evaluate single-photon implementations of QKD. Here we use them to investigate a realistic source of weak coherent pulses. The resulting upper bounds can be formulated as a convex optimization problem known as a semidefinite program which can be efficiently solved. For the standard four-state QKD protocol, they are quite close to known lower bounds, thus showing that there are clear limits to the further improvement of classical post-processing techniques in decoy state QKD.Comment: 10 pages, 3 figure

Blowfly flight characteristics are shaped by environmental features and controlled by optic flow information

Kern R, Boeddeker N, Dittmar L, Egelhaaf M. Blowfly flight characteristics are shaped by environmental features and controlled by optic flow information. Journal of Experimental Biology. 2012;215(14):2501-2514.Blowfly flight consists of two main components, saccadic turns and intervals of mostly straight gaze direction, although, as a consequence of inertia, flight trajectories usually change direction smoothly. We investigated how flight behavior changes depending on the surroundings and how saccadic turns and intersaccadic translational movements might be controlled in arenas of different width with and without obstacles. Blowflies do not fly in straight trajectories, even when traversing straight flight arenas; rather, they fly in meandering trajectories. Flight speed and the amplitude of meanders increase with arena width. Although saccade duration is largely constant, peak angular velocity and succession into either direction are variable and depend on the visual surroundings. Saccade rate and amplitude also vary with arena layout and are correlated with the 'time-to-contact' to the arena wall. We provide evidence that both saccade and velocity control rely to a large extent on the intersaccadic optic flow generated in eye regions looking well in front of the fly, rather than in the lateral visual field, where the optic flow at least during forward flight tends to be strongest

Integration des Community-Gedankens in das Collaborative Engineering am Beispiel des Schiffbaus

E-Collaboration als aktuell vieldiskutierte Form der zwischenbetrieblichen Zusammenarbeit bietet Unternehmen auch im Bereich der Produktentwicklung neue Möglichkeiten, dem steigenden Wettbewerbsdruck zu begegnen. Zielsetzung dieses Beitrages ist es, das Konzept des Collaborative Engineering darzustellen und durch die Idee der Communities, die sich als neue Organisationsform von Benutzern elektronischer Kommunikationsmedien entwickelt haben, zu erweitern. Dazu werden am Beispiel des Schiffbaus aktuelle Fragestellungen diskutiert sowie ein Lösungsansatz für eine Collaborative Engineering Plattform vorgestellt. Darauf aufbauend wird der Community- Gedanke auf die Produktentwicklung übertragen; Anforderungen an Communities im Engineering-Bereich werden abgeleitet. Abschließend erfolgt die Beschreibung einer Rahmenarchitektur sowie die Formulierung von Forschungsfragen zur Realisierung von Collaborative Engineering Communities

Long-term performance of simultaneous measurement of stable isotopes of oxygen and carbon in cellulose with a high-temperature pyrolysis/gas chromatography/isotope ratio mass spectrometry system at the Institute for Geological and Geochemical Research

A high-temperature pyrolysis/gas chromatography/isotope ratio mass spectrometry system was established at the Institute for Geological and Geochemical Research in 2013. A dedicated field of application of the system is the simultaneous measurement of stable carbon and oxygen isotope ratios in the cellulose of modern, relict and subfossil plant tissues and sediments. The measurement protocol was fine-tuned during the first year of operation and documented in detail in this report. To quantify the long-term reproducibility of the simultaneous measurement of stable isotopes of oxygen and carbon in cellulose, a 2σ range inferred from repeated measurements of a Quality Assurance standard can be recommended: 0.16 and 0.20‰, for δ 13 C and δ 18 O, respectively. An extensive set of samples with known pyrolysis-based δ 13 C data was analyzed in combustion mode and the paired results were used to assess the necessity of adjustment of the pyrolysis-based δ 13 C measurements. The variances of the two datasets were not significantly different; the slope (intercept) of the regression was indistinguishable from unity (zero), suggesting that probably owing to the relatively frequent cleaning of the pyrolysis furnace, pyrolysis-based δ 13 C data neither suffer from a variance bias nor require a specific adjustment