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Article ; Online: Aversive view memories and risk perception in navigating ants

Cody A. Freas / Antoine Wystrach / Sebastian Schwarz / Marcia L. Spetch

Scientific Reports, Vol 12, Iss 1, Pp 1-

2022 Volume 15

Abstract: Abstract Many ants establish foraging routes through learning views of the visual panorama. Route models have focused primarily on attractive view use, which experienced foragers orient towards to return to known sites. However, aversive views have ... ...

Abstract	Abstract Many ants establish foraging routes through learning views of the visual panorama. Route models have focused primarily on attractive view use, which experienced foragers orient towards to return to known sites. However, aversive views have recently been uncovered as a key component of route learning. Here, Cataglyphis velox rapidly learned aversive views, when associated with a negative outcome, a period of captivity in vegetation, triggering increases in hesitation behavior. These memories were based on the accumulation of experiences over multiple trips with each new experience regulating forager hesitancy. Foragers were also sensitive to captivity time differences, suggesting they possess some mechanism to quantify duration. Finally, we analyzed foragers' perception of risky (i.e. variable) versus stable aversive outcomes by associating two sites along the route with distinct captivity schedules, a fixed or variable duration, with the same mean across training. Foragers exhibited fewer hesitations in response to risky outcomes compared to fixed ones, indicating they perceived risky outcomes as less severe. Results align with a logarithmic relationship between captivity duration and hesitations, suggesting that aversive stimulus perception is a logarithm of its actual value. We discuss how aversive view learning could be executed within the mushroom bodies circuitry following a prediction error rule.
Keywords	Medicine ; R ; Science ; Q
Subject code	150
Language	English
Publishing date	2022-02-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Using Machine Learning Methods for Predicting Cage Performance Criteria in an Angular Contact Ball Bearing

Sebastian Schwarz / Hannes Grillenberger / Oliver Graf-Goller / Marcel Bartz / Stephan Tremmel / Sandro Wartzack

Lubricants, Vol 10, Iss 25, p

2022 Volume 25

Abstract: Rolling bearings have to meet the highest requirements in terms of guidance accuracy, energy efficiency, and dynamics. An important factor influencing these performance criteria is the cage, which has different effects on the bearing dynamics depending ... ...

Abstract	Rolling bearings have to meet the highest requirements in terms of guidance accuracy, energy efficiency, and dynamics. An important factor influencing these performance criteria is the cage, which has different effects on the bearing dynamics depending on the cage’s geometry and bearing load. Dynamics simulations can be used to calculate cage dynamics, which exhibit high agreement with the real cage motion, but are time-consuming and complex. In this paper, machine learning algorithms were used for the first time to predict physical cage related performance criteria in an angular contact ball bearing. The time-efficient prediction of the machine learning algorithms enables an estimation of the dynamic behavior of a cage for a given load condition of the bearing within a short time. To create a database for machine learning, a simulation study consisting of 2000 calculations was performed to calculate the dynamics of different cages in a ball bearing for several load conditions. Performance criteria for assessing the cage dynamics and frictional behavior of the bearing were derived from the calculation results. These performance criteria were predicted by machine learning algorithms considering bearing load and cage geometry. The predictions for a total of 10 target variables reached a coefficient of determination of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>≈</mo><mn>0.94</mn></mrow></semantics></math> for the randomly selected test data sets, demonstrating high accuracy of the models.
Keywords	rolling bearing dynamics ; cage instability ; regression ; machine learning ; neural networks ; random forest ; Science ; Q
Subject code	670
Language	English
Publishing date	2022-02-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Distinct roles of nonmuscle myosin II isoforms for establishing tension and elasticity during cell morphodynamics

Kai Weißenbruch / Justin Grewe / Marc Hippler / Magdalena Fladung / Moritz Tremmel / Kathrin Stricker / Ulrich Sebastian Schwarz / Martin Bastmeyer

eLife, Vol

2021 Volume 10

Abstract: Nonmuscle myosin II (NM II) is an integral part of essential cellular processes, including adhesion and migration. Mammalian cells express up to three isoforms termed NM IIA, B, and C. We used U2OS cells to create CRISPR/Cas9-based knockouts of all three ...

Abstract	Nonmuscle myosin II (NM II) is an integral part of essential cellular processes, including adhesion and migration. Mammalian cells express up to three isoforms termed NM IIA, B, and C. We used U2OS cells to create CRISPR/Cas9-based knockouts of all three isoforms and analyzed the phenotypes on homogenously coated surfaces, in collagen gels, and on micropatterned substrates. In contrast to homogenously coated surfaces, a structured environment supports a cellular phenotype with invaginated actin arcs even in the absence of NM IIA-induced contractility. A quantitative shape analysis of cells on micropatterns combined with a scale-bridging mathematical model reveals that NM IIA is essential to build up cellular tension during initial stages of force generation, while NM IIB is necessary to elastically stabilize NM IIA-generated tension. A dynamic cell stretch/release experiment in a three-dimensional scaffold confirms these conclusions and in addition reveals a novel role for NM IIC, namely the ability to establish tensional homeostasis.
Keywords	actomyosin ; NM II isoforms ; contractility ; cell shape ; intracellular forces ; mathematical modeling ; Medicine ; R ; Science ; Q ; Biology (General) ; QH301-705.5
Subject code	612
Language	English
Publishing date	2021-08-01T00:00:00Z
Publisher	eLife Sciences Publications Ltd
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Bringing IoT to the Lab

Marc Porr / Sebastian Schwarz / Ferdinand Lange / Laura Niemeyer / Thorleif Hentrop / Daniel Marquard / Patrick Lindner / Thomas Scheper / Sascha Beutel

HardwareX, Vol 8, Iss , Pp e00118- (2020)

SiLA2 and Open-Source-Powered Gateway Module for Integrating Legacy Devices into the Digital Laboratory

2020

Abstract: In this article a gateway module to integrate legacy laboratory devices into the network of the digital laboratory in the 21st century is introduced. The device is based on ready to buy consumer hardware that is easy to get and inexpensive. Depending on ... ...

Abstract	In this article a gateway module to integrate legacy laboratory devices into the network of the digital laboratory in the 21st century is introduced. The device is based on ready to buy consumer hardware that is easy to get and inexpensive. Depending on the specific requirements of the desired application (bare embedded computer, RS232 serial port connector, IP65 certified casing and connectors) the needed investment ranges from about 95 € up to 200 €. The embedded computer runs an open source Linux operating system and can in principle be used to run any kind of software needed for communicating with the laboratory device. Here the open source SiLA2 standard is used for presenting the device’s functions in the network. As an example the digital integration of a magnetic stirrer is shown and can be used as a template for other applications. A method for easy remote integration of the device to ensure an easy and consistent workflow in development, testing and usage is also presented. This incorporates a method for remote installation of SiLA2 servers on the box as well as a web frontend for administration, debugging and management of those.
Keywords	Digital integration ; Embedded computing ; Network ; Internet of things (IoT) ; SiLA2 ; Laboratory ; Science (General) ; Q1-390
Subject code	600
Language	English
Publishing date	2020-10-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The sedentary (r)evolution

Jens Freese / Rainer Johannes Klement / Begoña Ruiz-Núñez / Sebastian Schwarz / Helmut Lötzerich

F1000Research, Vol

Have we lost our metabolic flexibility? [version 2; referees: 2 approved, 1 approved with reservations]

2018 Volume 6

Abstract: During the course of evolution, up until the agricultural revolution, environmental fluctuations forced the human species to develop a flexible metabolism in order to adapt its energy needs to various climate, seasonal and vegetation conditions. ... ...

Abstract	During the course of evolution, up until the agricultural revolution, environmental fluctuations forced the human species to develop a flexible metabolism in order to adapt its energy needs to various climate, seasonal and vegetation conditions. Metabolic flexibility safeguarded human survival independent of food availability. In modern times, humans switched their primal lifestyle towards a constant availability of energy-dense, yet often nutrient-deficient, foods, persistent psycho-emotional stressors and a lack of exercise. As a result, humans progressively gain metabolic disorders, such as the metabolic syndrome, type 2 diabetes, non-alcoholic fatty liver disease, certain types of cancer, cardiovascular disease and Alzheimer´s disease, wherever the sedentary lifestyle spreads in the world. For more than 2.5 million years, our capability to store fat for times of food shortage was an outstanding survival advantage. Nowadays, the same survival strategy in a completely altered surrounding is responsible for a constant accumulation of body fat. In this article, we argue that the metabolic disease epidemic is largely based on a deficit in metabolic flexibility. We hypothesize that the modern energetic inflexibility, typically displayed by symptoms of neuroglycopenia, can be reversed by re-cultivating suppressed metabolic programs, which became obsolete in an affluent environment, particularly the ability to easily switch to ketone body and fat oxidation. In a simplified model, the basic metabolic programs of humans’ primal hunter-gatherer lifestyle are opposed to the current sedentary lifestyle. Those metabolic programs, which are chronically neglected in modern surroundings, are identified and conclusions for the prevention of chronic metabolic diseases are drawn.
Keywords	Developmental Evolution ; Preventive Medicine ; Social & Behavioral Determinants of Health ; Medicine ; R ; Science ; Q
Subject code	570
Language	English
Publishing date	2018-02-01T00:00:00Z
Publisher	F1000 Research Ltd
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Extracellular Matrix Geometry and Initial Adhesive Position Determine Stress Fiber Network Organization during Cell Spreading

Elena Kassianidou / Dimitri Probst / Julia Jäger / Stacey Lee / Anne-Lou Roguet / Ulrich Sebastian Schwarz / Sanjay Kumar

Cell Reports, Vol 27, Iss 6, Pp 1897-1909.e

2019 Volume 4

Abstract: Summary: Three-dimensional matrices often contain highly structured adhesive tracks that require cells to turn corners and bridge non-adhesive areas. Here, we investigate these complex processes using micropatterned cell adhesive frames. Spreading ... ...

Abstract	Summary: Three-dimensional matrices often contain highly structured adhesive tracks that require cells to turn corners and bridge non-adhesive areas. Here, we investigate these complex processes using micropatterned cell adhesive frames. Spreading kinetics on these matrices depend strongly on initial adhesive position and are predicted by a cellular Potts model (CPM), which reflects a balance between adhesion and intracellular tension. As cells spread, new stress fibers (SFs) assemble periodically and parallel to the leading edge, with spatial intervals of ∼2.5 μm, temporal intervals of ∼15 min, and characteristic lifetimes of ∼50 min. By incorporating these rules into the CPM, we can successfully predict SF network architecture. Moreover, we observe broadly similar behavior when we culture cells on arrays of discrete collagen fibers. Our findings show that ECM geometry and initial cell position strongly determine cell spreading and that cells encode a memory of their spreading history through SF network organization. : Kassianidou et al. use adhesive micropatterns to recapitulate features of 3D extracellular matrices and to integrate live-cell imaging with mathematical modeling. They find that spreading trajectories are determined by a balance between adhesion energy, surface tension, and line tension, and that cells produce a stress fiber network that encodes the spreading history. Keywords: cell-matrix adhesion, cell shape, cell spreading, actin cytoskeleton, stress fibers, mathematical modeling, cellular Potts model, cell memory, mechanobiology, cell migration
Keywords	Biology (General) ; QH301-705.5
Subject code	612
Language	English
Publishing date	2019-05-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The sedentary (r)evolution

Jens Freese / Rainer Johannes Klement / Begoña Ruiz-Núñez / Sebastian Schwarz / Helmut Lötzerich

F1000Research, Vol

Have we lost our metabolic flexibility? [version 1; referees: 2 approved]

2017 Volume 6

Abstract	During the course of evolution, up until the agricultural revolution, environmental fluctuations forced the human species to develop a flexible metabolism in order to adapt its energy needs to various climate, seasonal and vegetation conditions. Metabolic flexibility safeguarded human survival independent of food availability. In modern times, humans switched their primal lifestyle towards a constant availability of energy-dense, yet often nutrient-deficient, foods, persistent psycho-emotional stressors and a lack of exercise. As a result, humans progressively gain metabolic disorders, such as the metabolic syndrome, type 2 diabetes, non-alcoholic fatty liver disease, certain types of cancer, cardiovascular disease and Alzheimer´s disease, wherever the sedentary lifestyle spreads in the world. For more than 2.5 million years, our capability to store fat for times of food shortage was an outstanding survival advantage. Nowadays, the same survival strategy in a completely altered surrounding is responsible for a constant accumulation of body fat. In this article, we argue that the metabolic epidemic is largely based on a deficit in metabolic flexibility. We hypothesize that the modern energetic inflexibility, typically displayed by symptoms of neuroglycopenia, can be reversed by re-cultivating suppressed metabolic programs, which became obsolete in an affluent environment, particularly the ability to easily switch to ketone body and fat oxidation. In a simplified model, the basic metabolic programs of humans’ primal hunter-gatherer lifestyle are opposed to the current sedentary lifestyle. Those metabolic programs, which are chronically neglected in modern surroundings, are identified and conclusions for the prevention of chronic metabolic diseases are drawn.
Keywords	Developmental Evolution ; Preventive Medicine ; Social & Behavioral Determinants of Health ; Medicine ; R ; Science ; Q
Subject code	570
Language	English
Publishing date	2017-10-01T00:00:00Z
Publisher	F1000 Research Ltd
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Nest Relocation and Colony Founding in the Australian Desert Ant, Melophorus bagoti Lubbock (Hymenoptera

Patrick Schultheiss / Sebastian Schwarz / Antoine Wystrach

Psyche: A Journal of Entomology, Vol

Formicidae)

2010 Volume 2010

Abstract: Even after years of research on navigation in the Red Honey Ant, Melophorus bagoti, much of its life history remains elusive. Here, we present observations on nest relocation and the reproductive and founding stages of colonies. Nest relocation is ... ...

Abstract	Even after years of research on navigation in the Red Honey Ant, Melophorus bagoti, much of its life history remains elusive. Here, we present observations on nest relocation and the reproductive and founding stages of colonies. Nest relocation is possibly aided by trail laying behaviour, which is highly unusual for solitary foraging desert ants. Reproduction occurs in synchronised mating flights, which are probably triggered by rain. Queens may engage in multiple matings, and there is circumstantial evidence that males are chemically attracted to queens. After the mating flight, the queens found new colonies independently and singly. Excavation of these founding colonies reveals first insights into their structure.
Keywords	Zoology ; QL1-991
Language	English
Publishing date	2010-01-01T00:00:00Z
Publisher	Hindawi Limited
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Beginnings of a synthetic approach to desert ant navigation

Cheng, Ken / Patrick Schultheiss / Sebastian Schwarz / Antoine Wystrach / RÃ¼diger Wehner

Behavioural processes. 2014 Feb., v. 102

2014

Abstract: In a synthetic approach to studying navigational abilities in desert ants, we review recent work comparing ants living in different visual ecologies. Those living in a visually rich habitat strewn with tussocks, bushes, and trees are compared to those ... ...

Abstract	In a synthetic approach to studying navigational abilities in desert ants, we review recent work comparing ants living in different visual ecologies. Those living in a visually rich habitat strewn with tussocks, bushes, and trees are compared to those living in visually barren salt pans, as exemplified by the Central Australian Melophorus bagoti and the North African Cataglyphis fortis, respectively. In bare habitats the navigator must rely primarily on path integration, keeping track of the distance and direction in which it has travelled, while in visually rich habitats the navigator can rely more on guidance by the visual panorama. Consistent with these expectations, C. fortis performs better than M. bagoti on various measures of precision at path integration. In contrast, M. bagoti learned a visually based associative task better than C. fortis, the latter generally failing at the task. Both these ants, however, exhibit a similar pattern of systematic search as a âback upâ strategy when other navigational strategies fail. A newly investigated salt-pan species of Melophorus (as yet unnamed) resembles C. fortis more, and its congener M. bagoti less, in its path integration. The synthetic approach would benefit from comparing more species chosen to address evolutionary questions.This article is part of a Special Issue entitled: CO3 2013.
Keywords	Cataglyphis ; Melophorus bagoti ; habitats ; trees
Language	English
Dates of publication	2014-02
Size	p. 51-61.
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	196999-7
ISSN	1872-8308 ; 0376-6357
ISSN (online)	1872-8308
ISSN	0376-6357
DOI	10.1016/j.beproc.2013.10.001
Database	NAL-Catalogue (AGRICOLA)

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Article: Crucial role of ultraviolet light for desert ants in determining direction from the terrestrial panorama

Schultheiss, Patrick / Antoine Wystrach / Sebastian Schwarz / Aloys Tack / Jeanne Delor / Sabine S. Nooten / Anne-Laurence Bibost / Cody A. Freas / Ken Cheng

The Association for the Study of Animal Behaviour Animal behaviour. 2016 May, v. 115

2016

Abstract: Ants use the panoramic skyline in part to determine a direction of travel. A theoretically elegant way to define where terrestrial objects meet the sky is to use an opponent-process channel contrasting green wavelengths of light with ultraviolet (UV) ... ...

Abstract	Ants use the panoramic skyline in part to determine a direction of travel. A theoretically elegant way to define where terrestrial objects meet the sky is to use an opponent-process channel contrasting green wavelengths of light with ultraviolet (UV) wavelengths. Compared with the sky, terrestrial objects reflect relatively more green wavelengths. Using such an opponent-process channel gains constancy in the face of changes in overall illumination level. We tested the use of UV wavelengths in desert ants by using a plastic that filtered out most of the energy below 400nm. Ants, Melophorus bagoti, were trained to home with an artificial skyline provided by an arena (experiment 1) or with the natural panorama (experiment 2). On a test, a homing ant was captured just before she entered her nest, and then brought back to a replicate arena (experiment 1) or the starting point (the feeder, experiment 2) and released. Blocking UV light led to deteriorations in orientation in both experiments. When the artificial skyline was changed from opaque to transparent UV-blocking plastic (experiment 3) on the other hand, the ants were still oriented. We conclude that UV wavelengths play a crucial role in determining direction based on the terrestrial surround.
Keywords	Melophorus bagoti ; animal behavior ; energy ; lighting ; nests ; plastics ; ultraviolet radiation ; wavelengths
Language	English
Dates of publication	2016-05
Size	p. 19-28.
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	281-1
ISSN	0003-3472
ISSN	0003-3472
DOI	10.1016/j.anbehav.2016.02.027
Database	NAL-Catalogue (AGRICOLA)

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