120 research outputs found
Santurismo: The Commodification of SanterÃa and the Touristic Value of Afro-Cuban Derived Religions in Cuba
Santurismo (SanterÃa + Turismo) refers to the popular formula of Afro-Cuban religions and tourism and initially served the Cuban government in the 1960s to promote SanterÃa as a folkloric product of Cuban identity through staged performances in touristic surroundings. Gradually, it became a coping strategy by Cuban people to deal with political and economic hardship during the Special Period in the 1990s which led to the emergence of diplo-santerÃa by so-called jinetero-santeros. While the continuous process of commodification of Cuban SanterÃa is marked by local social, economic and political influences, it also relates to current tendencies in comparable religious and spiritual phenomena at a global level. This research paper is based on an extensive literature review as well as on ethnographic fieldwork conducted in Cuba in 2016. It aims at showing in which ways Afro-Cuban religions have worked their way up from a stigmatized and persecuted religious system to a widely valorized religion in the spiritual and touristic sphere. While warning for the consequences of its commodification, it also shows that, over time, SanterÃa has proved to serve as a weapon for resistance and struggle, which is still ongoing in Cuban society today
How Do Students Use Basic Aspects Of Functions When Learning Mathematics In A Chemistry Context?
An Integrative Model for Phytochrome B Mediated Photomorphogenesis: From Protein Dynamics to Physiology
Background: Plants have evolved various sophisticated mechanisms to respond and adapt to changes of abiotic factors in their natural environment. Light is one of the most important abiotic environmental factors and it regulates plant growth and development throughout their entire life cycle. To monitor the intensity and spectral composition of the ambient light environment, plants have evolved multiple photoreceptors, including the red/far-red light-sensing phytochromes. Methodology/Principal Findings: We have developed an integrative mathematical model that describes how phytochrome B (phyB), an essential receptor in Arabidopsis thaliana, controls growth. Our model is based on a multiscale approach and connects the mesoscopic intracellular phyB protein dynamics to the macroscopic growth phenotype. To establish reliable and relevant parameters for the model phyB regulated growth we measured: accumulation and degradation, dark reversion kinetics and the dynamic behavior of different nuclear phyB pools using in vivo spectroscopy, western blotting and Fluorescence Recovery After Photobleaching (FRAP) technique, respectively. Conclusions/Significance: The newly developed model predicts that the phyB-containing nuclear bodies (NBs) (i) serve as storage sites for phyB and (ii) control prolonged dark reversion kinetics as well as partial reversibility of phyB Pfr in extended darkness. The predictive power of this mathematical model is further validated by the fact that we are able to formalize a basic photobiological observation, namely that in light-grown seedlings hypocotyl length depends on the total amount o
Grundvorstellungen in der anwendungsbezogenen Mathematikbildung der Studieneingangsphase
In den natur- und ingenieurwissenschaftlichen Studiengängen an Hochschulen der angewandten Wissenschaften stellt der Mathematik-Anteil in der Studieneingangsphase eine große Hürde dar. Dies führt unter anderem zu Studienabbrüchen in den ersten beiden Semestern (Neugebauer et al., 2019). Um der Abbruchrate sowie kalküllastigen Zugangsweisen zur Mathematik entgegenzuwirken, wurde eine Selbstlernumgebung für Studierende entwickelt. Sie ist an mathematischen Grundvorstellungen sowie studienrelevanten Kontexten orientiert und soll das funktionale Denken fördern. Konkret werden exponentielle und lineare funktionale Zusammenhänge im Anwendungskontext zeitlicher Konzentrationsverläufe bei einer chemischen Reaktion untersucht. Die Reaktion wird durch eine Simulation in GeoGebra vereinfacht dargestellt, wodurch verstärkt die Kovariationsvorstellung gefördert wird (Lichti, 2019). Nach einer kurzen Einführung in die Simulation werden die Inhalte anhand der Simulation und daneben angeordneten Funktionsgraphen erarbeitet. Dies hat sich als lerneffizient für funktionales Denken erwiesen (Rolfes et al., 2021). Durch den Anwendungsbezug wird eine höhere Sinnstiftung und Vorbereitung auf das weiterführende (Fach-)Studium angestrebt. Der Kontext für die Lernumgebung wurde so gewählt, dass er für mehr als die Hälfte der Studienanfänger*innen inhaltlich studienrelevant ist. Die Einflüsse der Lernumgebung auf das konzeptuelle Verständnis des funktionalen Denkens werden mit dem FALKE-Test (Klinger & Barzel, 2018) in einem Kontrollgruppen Prä-Posttest Design überprüft. Darüber hinaus werden zu Vorlesungsbeginn und -ende jeweils verschiedene affektive Merkmale, u.a. Motivation und Selbstwirksamkeit, erhoben
Decomposing Noise in Biochemical Signaling Systems Highlights the Role of Protein Degradation
AbstractStochasticity is an essential aspect of biochemical processes at the cellular level. We now know that living cells take advantage of stochasticity in some cases and counteract stochastic effects in others. Here we propose a method that allows us to calculate contributions of individual reactions to the total variability of a system’s output. We demonstrate that reactions differ significantly in their relative impact on the total noise and we illustrate the importance of protein degradation on the overall variability for a range of molecular processes and signaling systems. With our flexible and generally applicable noise decomposition method, we are able to shed new, to our knowledge, light on the sources and propagation of noise in biochemical reaction networks; in particular, we are able to show how regulated protein degradation can be employed to reduce the noise in biochemical systems
Induction level determines signature of gene expression noise in cellular systems
Noise in gene expression, either due to inherent stochasticity or to varying
inter- and intracellular environment, can generate significant cell-to-cell
variability of protein levels in clonal populations. We present a theoretical
framework, based on stochastic processes, to quantify the different sources of
gene expression noise taking cell division explicitly into account. Analytical,
time-dependent solutions for the noise contributions arising from the major
steps involved in protein synthesis are derived. The analysis shows that the
induction level of the activator or transcription factor is crucial for the
characteristic signature of the dominant source of gene expression noise and
thus bridges the gap between seemingly contradictory experimental results.
Furthermore, on the basis of experimentally measured cell distributions, our
simulations suggest that transcription factor binding and promoter activation
can be modelled independently of each other with sufficient accuracy
Stochastic modelling, Bayesian inference, and new in vivo measurements elucidate the debated mtDNA bottleneck mechanism
Dangerous damage to mitochondrial DNA (mtDNA) can be ameliorated during
mammalian development through a highly debated mechanism called the mtDNA
bottleneck. Uncertainty surrounding this process limits our ability to address
inherited mtDNA diseases. We produce a new, physically motivated, generalisable
theoretical model for mtDNA populations during development, allowing the first
statistical comparison of proposed bottleneck mechanisms. Using approximate
Bayesian computation and mouse data, we find most statistical support for a
combination of binomial partitioning of mtDNAs at cell divisions and random
mtDNA turnover, meaning that the debated exact magnitude of mtDNA copy number
depletion is flexible. New experimental measurements from a wild-derived mtDNA
pairing in mice confirm the theoretical predictions of this model. We
analytically solve a mathematical description of this mechanism, computing
probabilities of mtDNA disease onset, efficacy of clinical sampling strategies,
and effects of potential dynamic interventions, thus developing a quantitative
and experimentally-supported stochastic theory of the bottleneck.Comment: Main text: 14 pages, 5 figures; Supplement: 17 pages, 4 figures;
Total: 31 pages, 9 figure
Fluorescence yield near edge spectroscopy of [pi]-bonded CO on Fe(100)
Near edge X-ray absorption fine structure (NEXAFS) spectra of CO adsorbed on the Fe(100) surface are reported. Spectra, obtained by fluorescence yield (FYNES), are presented for each of the four individual CO adsorption configurations observed on this surface. The [pi]-bonded state exhibits an unusual FYNES spectrum and polarization dependence which indicates that the molecule is either extensively rehybridized or tilted with respect to the surface normal. The FYNES spectra of each of the adsorption states directly reflect the perturbation of the carbon-oxygen bond by the surface and track systematically with the heat of adsorption.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27641/1/0000017.pd
Molecular mechanisms for mediating light-dependent nucleo/cytoplasmic partitioning of phytochrome photoreceptors
The photoreceptors phytochromes monitor the red/far-red part of the spectrum, exist in the biologically active Pfr (far-red absorbing) or inactive Pr (red absorbing) forms, and function as red/far-red light-regulated molecular switches to modulate plant development and growth. Phytochromes are synthesized in the cytoplasm, and light induces translocation of the Pfr conformer into the nucleus. Nuclear import of phytochromes is a highly regulated process and is fine-tuned by the quality and quantity of light. It appears that phytochrome A (phyA) and phytochrome B (phyB) do not possess active endogenous nuclear import signals (NLSs), thus light-induced translocation of these photoreceptors into the nucleus requires direct protein–protein interactions with their NLS-containing signaling partners. Sub-cellular partitioning of the various phytochrome species is mediated by different molecular machineries. Translocation of phyA into the nucleus is promoted by FAR-RED ELONGATED HYPOCOTYL 1 (FHY1) and FHY1-LIKE (FHL), but the identity of nuclear transport facilitators mediating the import of phyB-E into the nucleus remains elusive. Phytochromes localized in the nucleus are associated with specific protein complexes, termed photobodies. The size and distribution of these structures are regulated by the intensity and duration of irradiation, and circumstantial evidence indicates that they are involved in fine-tuning phytochrome signaling
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