750 research outputs found

    Frz. quoi als Diskursmarker

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    This contribution deals with the different uses of French quoi as a discourse marker. These uses are described in such a way that it will become clear why in certain circumstances the use of quoi, as pointed out in the recent literature (cf. Beeching 2006), counts as polite. It will, however, also become clear why, in other circumstances, its use is considered downright impolite. The second aspect of quoi that is discussed in this article concerns its still ill-understood use to mark the closure of a problematic (i.e. unsmooth, disfluent) formulation. It will be argued that Chafe's (1994) and Langacker's (2001) notion of attentional framing provides a useful basis for a more complete understanding of this type of use

    Using all-sky differential photometry to investigate how nocturnal clouds darken the night sky in rural areas

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    Artificial light at night has affected most of the natural nocturnal landscapes worldwide and the subsequent light pollution has diverse effects on flora, fauna and human well-being. To evaluate the environmental impacts of light pollution, it is crucial to understand both the natural and artificial components of light at night under all weather conditions. The night sky brightness for clear skies is relatively well understood and a reference point for a lower limit is defined. However, no such reference point exists for cloudy skies. While some studies have examined the brightening of the night sky by clouds in urban areas, the published data on the (natural) darkening by clouds is very sparse. Knowledge of reference points for the illumination of natural nocturnal environments however, is essential for experimental design and ecological modeling to assess the impacts of light pollution. Here we use differential all-sky photometry with a commercial digital camera to investigate how clouds darken sky brightness at two rural sites. The spatially resolved data enables us to identify and study the nearly unpolluted parts of the sky and to set an upper limit on ground illumination for overcast nights at sites without light pollution.Comment: 17 pages, 6 figure

    Delokutivität, Possessive und die italienischen Verwandtschaftsbezeichnungen

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    This contribution is about a hitherto unexplained phenomenon of Italian syntax, i.e. the lack of a determiner in nominal expressions of a certain type that contain a possessive and a kinship noun as its scope, despite the fact that possessives normally require a determiner. So, my car is la mia macchina in Italian, whereas my son translates as mio figlio. It is argued that a plausible solution to this puzzle can be given by using Benveniste's notion of delocutivity. Therefore, the first part of the article presents the concept of delocutivity, mainly drawing on French examples. The main purpose of this introductory part is to show that the class of delocutive expressions is not restricted to verbs

    Evaluating the summer night sky brightness at a research field site on Lake Stechlin in northeastern Germany

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    We report on luminance measurements of the summer night sky at a field site on a freshwater lake in northeastern Germany (Lake Stechlin) to evaluate the amount of artificial skyglow from nearby and distant towns in the context of a planned study on light pollution. The site is located about 70 km north of Berlin in a rural area possibly belonging to one of the darkest regions in Germany. Continuous monitoring of the zenith sky luminance between June and September 2015 was conducted utilizing a Sky Quality Meter. With this device, typical values for clear nights in the range of 21.5-21.7 magSQM/_{SQM}/arcsec2^2 were measured, which is on the order of the natural sky brightness during starry nights. On overcast nights, values down to 22.84 magSQM/_{SQM}/arcsec2^2 were obtained, which is about one third as bright as on clear nights. The luminance measured on clear nights as well as the darkening with the presence of clouds indicate that there is very little influence of artificial skyglow on the zenith sky brightness at this location. Furthermore, fish-eye lens sky imaging luminance photometry was performed with a digital single-lens reflex camera on a clear night in the absence of moonlight. The photographs unravel several distant towns as possible sources of light pollution on the horizon. However, the low level of artificial skyglow makes the field site at Lake Stechlin an excellent location to study the effects of skyglow on a lake ecosystem in a controlled fashion.Comment: 20 pages, 8 figures, Journal of Quantitative Spectroscopy and Radiative Transfer 201

    An individual-based approach to depict the influence of the feeding strategy on the population structure of roach (Rutilus rutilus L.)

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    AbstractWe used an individual-based modelling strategy to simulate the growth of a roach population. Individual growth is based on food utilization, bioenergetics, spatial distribution, and seasonal influences. With this approach, it is possible to connect the animals' activity pattern with the energetic needs required for this activity. This allows investigating the role of spatial heterogeneity and individual variability for the dynamics of fish growth. The parameterisation is based on laboratory measurements and field studies performed at Lake Belau (Schleswig-Holstein, Northern Germany). The interactions of the behavioural repertoire, growth processes, and food preferences emerge in the context of a decreasing proportion of zooplankton in the food composition of simulated roach. Roach feeding on molluscs grow faster. The ontogenetic shift is related to the necessity to switch to larger prey as a consequence of the increase of energetic demands with body size

    Imaging and mapping the impact of clouds on skyglow with all-sky photometry

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    Artificial skyglow is constantly growing on a global scale, with potential ecological consequences ranging up to affecting biodiversity. To understand these consequences, worldwide mapping of skyglow for all weather conditions is urgently required. In particular, the amplification of skyglow by clouds needs to be studied, as clouds can extend the reach of skyglow into remote areas not affected by light pollution on clear nights. Here we use commercial digital single lens reflex cameras with fisheye lenses for all-sky photometry. We track the reach of skyglow from a peri-urban into a remote area on a clear and a partly cloudy night by performing transects from the Spanish town of Balaguer towards Montsec Astronomical Park. From one single all-sky image, we extract zenith luminance, horizontal and scalar illuminance. While zenith luminance reaches near-natural levels at 5km distance from the town on the clear night, similar levels are only reached at 27km on the partly cloudy night. Our results show the dramatic increase of the reach of skyglow even for moderate cloud coverage at this site. The powerful and easy-to-use method promises to be widely applicable for studies of ecological light pollution on a global scale also by non-specialists in photometry.Comment: 13 pages, 7 figure

    Measuring Light Pollution with Fisheye Lens Imagery from A Moving Boat, A Proof of Concept

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    Near all-sky imaging photometry was performed from a boat on the Gulf of Aqaba to measure the night sky brightness in a coastal environment. The boat was not anchored, and therefore drifted and rocked. The camera was mounted on a tripod without any inertia/motion stabilization. A commercial digital single lens reflex (DSLR) camera and fisheye lens were used with ISO setting of 6400, with the exposure time varied between 0.5 s and 5 s. We find that despite movement of the vessel the measurements produce quantitatively comparable results apart from saturation effects. We discuss the potential and limitations of this method for mapping light pollution in marine and freshwater systems. This work represents the proof of concept that all-sky photometry with a commercial DSLR camera is a viable tool to determine light pollution in an ecological context from a moving boat.Comment: 9 pages, 6 figures, accepted at International Journal of Sustainable Lightin

    Artificial light and nocturnal activity in gammarids

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    Artificial light is gaining attention as a potential stressor to aquatic ecosystems. Artificial lights located near streams increase light levels experienced by stream invertebrates and we hypothesized light would depress night drift rates. We also hypothesized that the effect of light on drift rates would decrease over time as the invertebrates acclimated to the new light level over the course of one month’s exposure. These hypotheses were tested by placing Gammarus spp. in eight, 75 m × 1 m artificial flumes. One flume was exposed to strong (416 lx) artificial light at night. This strong light created a gradient between 4.19 and 0.04 lx over the neighboring six artificial flumes, while a control flume was completely covered with black plastic at night. Night-time light measurements taken in the Berlin area confirm that half the flumes were at light levels experienced by urban aquatic invertebrates. Surprisingly, no light treatment affected gammarid drift rates. In contrast, physical activity measurements of in situ individually caged G. roeseli showed they increased short-term activity levels in nights of complete darkness and decreased activity levels in brightly lit flumes. Both nocturnal and diurnal drift increased, and day drift rates were unexpectadly higher than nocturnal drift

    Light intensity and spectral distribution affect chytrid infection of cyanobacteriaviamodulation of host fitness

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    Light gradients are an inherent feature in aquatic ecosystems and play a key role in shaping the biology of phytoplankton. Parasitism by chytrid fungi is gaining increasing attention as a major control agent of phytoplankton due to its previously overlooked ubiquity, and profound ecological and evolutionary consequences. Despite this interest, if and how light conditions modulate phytoplankton chytridiomycosis remains poorly studied. We investigated life-history traits of a chytrid parasite,Rhizophydium megarrhizum, under different light intensities and spectral compositions when infecting two closely related planktonic cyanobacteria with different light-harvesting strategies:Planktothrix rubescensandP. agardhii. In general, parasite transmission was highest under light conditions (both intensity and quality) that maximized growth rates for uninfected cyanobacteria. Chytrid encystment on hosts was significantly affected by light intensity and host strain identity. This likely resulted from higher irradiances stimulating the increased discharge of photosynthetic by-products, which drive parasite chemotaxis, and from strain-specific differences at the cell-surface. Comparisons of parasite transmission and host growth rates under different light conditions suggest the potential for epidemic development at higher irradiances, whereas host and parasite could coexist without epidemic outbreaks at lower light levels. These results illustrate the close relationship between parasite transmission and host fitness, which is ultimately modulated by the external environment
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