490 research outputs found
The embodiment of power and communalism in space and bodily contact
Imagine you visit a village on some remote island, with a culture with which you are not familiar. On this island, you discover a number of strange behaviors of which you try to make sense. For instance, some of the islanders rub their noses with each other as a greeting. You also learn that others eat potions “using combinations of ingredients such as rocks from the tallest mountain-peaks and epiphytes growing atop the highest trees” (Fiske, 2004, p. 95). How would you interpret these behaviors? Perhaps you would guess those with nose-to-nose contact are generally close to each other, and those eating the potions made of high things enjoy or attain high status. What you have figured out then are perhaps the two most basic and important dimensions of social relations: community relations and power relations (Mead, 1934).
What is the basis of such a judgment that relates unknown behaviors to social relations? In this chapter, we will approach this question from the standpoint of Relational Models Theory (RMT) developed by Fiske (1992; Fiske & Haslam, 2005). This theory identifies community and power as two of the basic relational models humans use to structure and coordinate their social interactions. In a nutshell, when people have a community relation or communal sharing (CS), they focus on what they have in common. Thus, resources are seen as common in a CS relation and shared according to needs.info:eu-repo/semantics/acceptedVersio
More than a metaphor: How the understanding of power is grounded in experience
Judgment and thinking about power, a universal form of human sociality, is intimately tied to spatial cues: Nonverbal communication, cultural produc-tion of power symbols, and metaphors of power all make use of the vertical spatial dimension. We argue that this overlap is due to a grounding of the concept of power in spatial thought. Evidence confirming this proposition can be found in experiments showing the impact of highly schematized spatial cues on judgments of power. We will discuss how semantic network theories, embodied theories of cognition, and conceptual metaphor theory fare in explaining and predicting the combined evidence on nonverbal be-havior, cultural production, and metaphors. In particular, we will ask what role language in the form of metaphors plays for our understanding of pow-er as size and elevation: Whether it is causal, or mainly an outcome of other processes that are not based on language.info:eu-repo/semantics/acceptedVersio
PhotoSpec: A new instrument to measure spatially distributed red and far-red Solar-Induced Chlorophyll Fluorescence
Solar-Induced Chlorophyll Fluorescence (SIF) is an emission of light in the 650–850 nm spectral range from the excited state of the chlorophyll-a pigment after absorption of photosynthetically active radiation (PAR). As this is directly linked to the electron transport chain in oxygenic photosynthesis, SIF is a powerful proxy for photosynthetic activity. SIF observations are relatively new and, while global scale measurements from satellites using high-resolution spectroscopy of Fraunhofer bands are becoming more available, observations at the intermediate canopy scale using these techniques are sparse.
We present a novel ground-based spectrometer system - PhotoSpec - for measuring SIF in the red (670–732 nm) and far-red (729–784 nm) wavelength range as well as canopy reflectance (400–900 nm) to calculate vegetation indices, such as the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), and the photochemical reflectance index (PRI). PhotoSpec includes a 2D scanning telescope unit which can be pointed to any location in a canopy with a narrow field of view (FOV = 0.7°). PhotoSpec has a high signal-to-noise ratio and spectral resolution, which allows high precision solar Fraunhofer line retrievals over the entire fluorescence wavelength range under all atmospheric conditions using a new two-step linearized least-squares retrieval procedure.
Initial PhotoSpec observations include the diurnal SIF cycle of single broad leaves, grass, and dark-light transitions. Results from the first tower-based measurements in Costa Rica show that the instrument can continuously monitor SIF of several tropical species throughout the day. The PhotoSpec instrument can be used to explore the relationship between SIF, photosynthetic efficiencies, Gross Primary Productivity (GPP), and the impact of canopy radiative transfer, viewing geometry, and stress conditions at the canopy scale
Tailoring the Absorption Properties of Black Silicon
AbstractSamples of crystalline silicon for use as solar cell material are structured and hyperdoped with sulfur by irradiation with femtosecond laser pulses under a sulfur hexafluoride atmosphere. The sulfur creates energy levels in the silicon band gap, allowing light absorption in the infrared wavelength regime, which offers the potential of a significant efficiency increase. This Black Silicon is a potential candidate for impurity or intermediate band photovoltaics. In this paper we determine the laser processed sulfur energy levels by deep-level transient spectroscopy (DLTS). We present how the number of laser pulses per sample spot influence the sulfur energy levels and hence the DLTS spectra. Further we show that changing the laser pulse by splitting it with a Michelson interferometer setup results in altered absorption which is most likely due to altered sulfur energy levels. This contribution focuses on the possibility of controlling the sulfur in Black Silicon through manipulating the laser pulse shape. As a first step samples of microstructured silicon are fabricated with doubled laser pulses at two different laser pulse distances and the absorption spectra by integrating sphere measurements are compared
Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters
The initial energy transfer in photosynthesis occurs between the
light-harvesting pigments and on ultrafast timescales. We analyze the
carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium
purpuratum as well as in an artificial light-harvesting dyad system by using
transient grating and two-dimensional electronic spectroscopy with 10 fs time
resolution. We find that F\"orster-type models reproduce the experimentally
observed 60 fs transfer times, but overestimate coupling constants, which leads
to a disagreement with both linear absorption and electronic 2D-spectra. We
show that a vibronic model, which treats carotenoid vibrations on both
electronic ground and excited state as part of the system's Hamiltonian,
reproduces all measured quantities. Importantly, the vibronic model presented
here can explain the fast energy transfer rates with only moderate coupling
constants, which are in agreement with structure based calculations.
Counterintuitively, the vibrational levels on the carotenoid electronic ground
state play a central role in the excited state population transfer to
bacteriochlorophyll as the resonance between the donor-acceptor energy gap and
vibrational ground state energies is the physical basis of the ultrafast energy
transfer rates in these systems
Untersuchungen zum Einfluss verschiedener Mund-Nase-Schutzmasken auf die beweissichere Atemalkoholmessung
Anlässlich eines richterlichen Gutachtenauftrages zur Frage, ob das Tragen von Mund-Nase-Schutzmasken zu einer Verfälschung des Atemalkoholmesswertes zuungunsten des Angeklagten führen kann, erfolgte unter Pandemiebedingungen eine experimentelle Testreihe an 6 gesunden Proband*innen (4 Männer, 2 Frauen), die risikoarmen Freizeitalkoholkonsum betrieben. Pro Untersuchungstag wurde jeweils ein Maskentyp (Op.-Maske, Textilmaske, FFP2-Maske) untersucht. Nach Aufnahme einer individuell berechneten Menge Alkohol und einer 30-minütigen Resorptionsphase erfolgten in halbstündigen Abständen 6 aufeinanderfolgende Atemalkoholmessungen, wobei zwischen den Messungen jeweils im Wechsel eine der Masken oder keine Maske getragen wurde. Anschließend wurden Wertepaare für Zeiträume mit und ohne Maske gebildet und die stündlichen Atemalkoholabbauraten berechnet. Im Ergebnis unterschieden sich die Atemalkoholabbauraten mit und ohne Masken nicht voneinander. Fehlermeldungen durch das Atemalkoholmessgerät, die auf das vorherige Tragen einer Maske zurückzuführen sind, traten nicht auf
Exploring pressure effects on metallic nanoparticles and surrounding media through plasmonic sensing
The sensing capabilities of gold nanorods under high-pressure conditions were investigated in methanol-ethanol mixtures (up to 13 GPa) and in water (up to 9 GPa) through their optical extinction. The longitudinal SPR band of AuNR exhibits a redshift with pressure which is the result of two main competing effects: compression of the conduction electrons which increases the bulk plasma frequency (blueshift) and increase in the solvent density (redshift). The variation in de SPR peak wavelength allows us to estimate the bulk modulus of the gold nanoparticles with a precision of 10 % and to obtain analytical functions providing the pressure dependence of the refractive index of water in three phases: liquid, ice VI and ice VII. Furthermore, the SPR band shows abrupt jumps at the liquid to ice phase VI and ice phase VII transitions, which are in accordance with the first-order character of these transitions.Financial support from Project PGC2018-101464-B-I00 (FEDER) and MALTA-Consolider Team (RED2018-102612-T) of the Ministerio de Ciencia, InnovaciĂłn y Universidades is acknowledged
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