scholarly journals Apparent Phototaxis Enabled by Brownian Motion

2020 ◽  
Author(s):  
Lukas Niese ◽  
Linlin Wang ◽  
Sayan Das ◽  
Juliane Simmchen
Keyword(s):  
Brownian Motion ◽  
Phototrophic Bacteria ◽  
Active Matter ◽  
Obvious Reason ◽  
Theoretical Considerations ◽  
Phototactic Behaviour ◽  
Do So

Biomimetic behaviour in artificially created active matter that allow deterministic and controlled motility has become of growing interest in recent years. It is well known that phototrophic bacteria optimize their position with respect to light by phototaxis. Here, we describe how our magnetic, photocatalytic microswimmers apparently undergo phototactic behaviour. Since there is no obvious reason for the particles to do so, we analyze different influences and elucidate through experiments and theoretical considerations from which physical circumstances this behaviour originates.

scholarly journals Apparent Phototaxis Enabled by Brownian Motion

2020 ◽  
Author(s):  
Lukas Niese ◽  
Linlin Wang ◽  
Sayan Das ◽  
Juliane Simmchen
Keyword(s):  
Brownian Motion ◽  
Phototrophic Bacteria ◽  
Active Matter ◽  
Obvious Reason ◽  
Theoretical Considerations ◽  
Phototactic Behaviour ◽  
Do So

Biomimetic behaviour in artificially created active matter that allow deterministic and controlled motility has become of growing interest in recent years. It is well known that phototrophic bacteria optimize their position with respect to light by phototaxis. Here, we describe how our magnetic, photocatalytic microswimmers apparently undergo phototactic behaviour. Since there is no obvious reason for the particles to do so, we analyze different influences and elucidate through experiments and theoretical considerations from which physical circumstances this behaviour originates.

IMPOSITION OF SANCTIONS ANALYSIS OF BUSINESS CRIME CRIMINAL ABORTION

2020 ◽  
Vol 2 (1) ◽  
pp. 25-29
Author(s):  
I Gusti Ngurah Ketut Hendra Gunawan
Keyword(s):  
Criminal Sanctions ◽  
Business Crime ◽  
Obvious Reason ◽  
Do So

Abortion is misconduct when committed intentionally abort way without any obvious reason to do so. Regarding the crime of abortion is regulated in the Act Positive in Indonesia. Perform abortions should not be just anyone do it because they have to kill the fetus in the womb. In this case I raised the issue that is how the imposition of criminal sanctions against perpetrators of criminal acts of abortion and how the alleviation and prevention of criminal acts of abortion in Indonesia.

Our Initial Issues, Revisited

2020 ◽  
pp. 321-373
Author(s):  
George E. Smith ◽  
Raghav Seth
Keyword(s):  
Brownian Motion ◽  
Molecular Theory ◽  
Fundamental Constants ◽  
Molecular Constants ◽  
And Brownian Motion ◽  
Do So

In addition to giving summary answers to the two issues singled out in Chapter 1—concerning (1) what Perrin established about Brownian motion itself and (2) how the standing of molecular theory changed between 1905 and 1913—the chapter answers three further questions raised by the intervening chapters: (3) What did Perrin and Brownian motion contribute to the new standing? (4) Given that Ostwald had already come to accept molecules before he encountered Perrin’s work, what led him to do so and what did the new standing amount to in his eyes? (5) How did the success in determining values for the interlinked principal molecular constants during the period of 1905 to 1913 contribute to the reliance on evidence from complementary theory-mediated measurements of interlinked “fundamental constants” that has been at the center of research in microphysics ever since?

scholarly journals Male-only care and cuckoldry in black coucals: does parenting hamper sex life?

2019 ◽  
Vol 286 (1900) ◽  
pp. 20182789 ◽  
Author(s):  
Ignas Safari ◽  
Wolfgang Goymann ◽  
Hanna Kokko
Keyword(s):  
Parental Care ◽  
Paternal Care ◽  
Real Life ◽  
Life Care ◽  
Trade Offs ◽  
Mating Opportunities ◽  
Siring Success ◽  
Theoretical Considerations ◽  
Operational Sex Ratios ◽  
Do So

Providing parental care often reduces additional mating opportunities. Paternal care becomes easier to understand if trade-offs between mating and caring remain mild. The black coucalCentropus grilliicombines male-only parental care with 50% of all broods containing young sired by another male. To understand how much caring for offspring reduces a male's chance to sire additional young in other males' nests, we matched the production of extra-pair young in each nest with the periods during which potential extra-pair sires were either caring for offspring themselves or when they had no own offspring to care for. We found that males which cared for a clutch were not fully excluded from the pool of competitors for siring young in other males' nests. Instead, the relative siring success showed a temporary dip. Males were approximately 17% less likely to sire young in other males' nests while they were incubating, about 48% less likely to do so while feeding nestlings, followed by 26% when feeding fledglings, compared to the success of males that currently did not care for offspring. These results suggest that real-life care situations by males may involve trade-off structures that differ from, and are less strict than those frequently employed in theoretical considerations of operational sex ratios, sex roles and parenting decisions.

Psychology's Theory Crisis, and Why Formal Modelling Cannot Solve It

2021 ◽  
Author(s):  
Freek Oude Maatman
Keyword(s):  
Psychological Theory ◽  
Current Theory ◽  
Formal Modelling ◽  
Explanatory Framework ◽  
The Core ◽  
Research Findings ◽  
Theoretical Considerations ◽  
Core Problem ◽  
Do So

In light of psychology’s ‘theory crisis’, multiple authors have recently argued that adopting the formalization of theories and/or formal modelling is a necessary or useful step towards stronger psychological theory. In this article, I instead argue that formal modelling cannot solve the core problem the psychological ‘theory crisis’ refers to, which are the currently high degrees of contrastive and holistic underdetermination of our theories by our data. I do so by first introducing underdetermination as an explanatory framework for determining the evidential import of research findings for theories, and showing how both broader theoretical considerations and informal assumptions are key to this process. Then, I derive the aforementioned core problem from current theory crisis literature and tentatively explore its possible solutions. Lastly, I show that formal modelling is neither a necessary nor sufficient solution for either contrastive or holistic underdetermination, and that its uncritical adoption might instead worsen the crisis.

scholarly journals Time to Say ‘Good Buy’ to the Passive Consumer? A Conceptual Review of the Consumer in the Bioeconomy

2021 ◽  
Vol 34 (4) ◽  
Author(s):  
Ulrich Wilke ◽  
Michael P. Schlaile ◽  
Sophie Urmetzer ◽  
Matthias Mueller ◽  
Kristina Bogner ◽  
...  
Keyword(s):  
Coming Of Age ◽  
Shared Responsibility ◽  
Central Research ◽  
Novel Technologies ◽  
Coding Scheme ◽  
Evolutionary Innovation ◽  
Consumer Responsibility ◽  
Research Gap ◽  
Theoretical Considerations ◽  
Do So

AbstractSuccessful transitions to a sustainable bioeconomy require novel technologies, processes, and practices as well as a general agreement about the overarching normative direction of innovation. Both requirements necessarily involve collective action by those individuals who purchase, use, and co-produce novelties: the consumers. Based on theoretical considerations borrowed from evolutionary innovation economics and consumer social responsibility, we explore to what extent consumers’ scope of action is addressed in the scientific bioeconomy literature. We do so by systematically reviewing bioeconomy-related publications according to (i) the extent to which consumers are regarded as passive vs. active, and (ii) different domains of consumer responsibility (depending on their power to influence economic processes). We find all aspects of active consumption considered to varying degrees but observe little interconnection between domains. In sum, our paper contributes to the bioeconomy literature by developing a novel coding scheme that allows us to pinpoint different aspects of consumer activity, which have been considered in a rather isolated and undifferentiated manner. Combined with our theoretical considerations, the results of our review reveal a central research gap which should be taken up in future empirical and conceptual bioeconomy research. The system-spanning nature of a sustainable bioeconomy demands an equally holistic exploration of the consumers’ prospective and shared responsibility for contributing to its coming of age, ranging from the procurement of information on bio-based products and services to their disposal.

scholarly journals Irreversibility in Active Matter: General Framework for Active Ornstein-Uhlenbeck Particles

2021 ◽  
Vol 8 ◽  
Author(s):  
Lennart Dabelow ◽  
Ralf Eichhorn
Keyword(s):  
Brownian Motion ◽  
Technical Note ◽  
Active Matter ◽  
Directed Motion ◽  
Central Importance ◽  
Uhlenbeck Process ◽  
Particle Distributions ◽  
Minimal Description ◽  
The Individual ◽  
Log Ratio

Active matter systems are driven out of equilibrium by conversion of energy into directed motion locally on the level of the individual constituents. In the spirit of a minimal description, active matter is often modeled by so-called active Ornstein-Uhlenbeck particles an extension of passive Brownian motion where activity is represented by an additional fluctuating non-equilibrium “force” with simple statistical properties (Ornstein-Uhlenbeck process). While in passive Brownian motion, entropy production along trajectories is well-known to relate to irreversibility in terms of the log-ratio of probabilities to observe a certain particle trajectory forward in time in comparison to observing its time-reversed twin trajectory, the connection between these concepts for active matter is less clear. It is therefore of central importance to provide explicit expressions for the irreversibility of active particle trajectories based on measurable quantities alone, such as the particle positions. In this technical note we derive a general expression for the irreversibility of AOUPs in terms of path probability ratios (forward vs. backward path), extending recent results from [PRX 9, 021009 (2019)] by allowing for arbitrary initial particle distributions and states of the active driving.

scholarly journals Fictional Expectations and the Constant Taming of a Spreading Technology

2021 ◽  
Vol 4 (12) ◽  
Author(s):  
Jakob Erichsen
Keyword(s):  
New Technology ◽  
Research Project ◽  
The Future ◽  
Theoretical Considerations ◽  
A Current ◽  
Do So

This essay argues that expectations about the future are a central category for understanding the paradoxical dynamics of the ongoing digitalization of schools. To do so, it outlines how to understand expectations about the future and which complementary concepts are particularly relevant. To illustrate the theoretical considerations, the essay uses empirical examples from a current research project focusing on the role of expectations in the debate on the digitalization of schools in Germany. The essay shows that looking at actors’ expectations helps to understand the continuous spread of new technology, as well as its constant taming.

scholarly journals A modified in-medium evolution equation with color coherence

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
João Barata ◽  
Fabio Domínguez ◽  
Carlos A. Salgado ◽  
Víctor Vila
Keyword(s):  
Brownian Motion ◽  
Evolution Equation ◽  
Quark Gluon Plasma ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Gluon Emission ◽  
Ion Collisions ◽  
Usual Procedure ◽  
Do So ◽  
Splitting Kernel

Abstract QCD jets produced in heavy-ion collisions at LHC or RHIC energies partially evolve inside the produced hot and dense quark gluon plasma, offering unique opportunities to study QCD splitting processes in different backgrounds. Induced (modified) splittings are expected to be the most relevant mechanism driving the modifications of in-medium jets compared to vacuum jets for a wide sets of observables. Although color coherence among different emitters has been identified as an essential mechanism in studies of the QCD antenna radiation, it is usually neglected in the multi-gluon medium-induced cascade. This independent gluon emission approximation can be analytically proved to be valid in the limit of very large media, but corrections or modifications to it have not been computed before in the context of the evolution (or rate) equation describing the gluon cascade. We propose a modified evolution equation that includes corrections due to the interference of subsequent emitters. In order to do so, we first compute a modified splitting kernel following the usual procedure of factorizing it from the subsequent Brownian motion. The calculation is performed in the two-gluon configuration with no overlapping formation times, that is expected to provide the first correction to the completely independent picture.

Integrated Fractional white Noise as an Alternative to Multifractional Brownian Motion

2007 ◽  
Vol 44 (02) ◽  
pp. 393-408 ◽  
Author(s):  
Allan Sly
Keyword(s):  
Stochastic Process ◽  
Brownian Motion ◽  
White Noise ◽  
Gaussian Process ◽  
Discrete Data ◽  
Hölder Exponent ◽  
Scaling Properties ◽  
Multifractional Brownian Motion ◽  
Local Properties

Multifractional Brownian motion is a Gaussian process which has changing scaling properties generated by varying the local Hölder exponent. We show that multifractional Brownian motion is very sensitive to changes in the selected Hölder exponent and has extreme changes in magnitude. We suggest an alternative stochastic process, called integrated fractional white noise, which retains the important local properties but avoids the undesirable oscillations in magnitude. We also show how the Hölder exponent can be estimated locally from discrete data in this model.

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