13 research outputs found

    The Black River: a comprehensive study of physical and chemical characteristics and their potential management implications.

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    An analysis of the Black River's biological and physicochemical characteristics was conducted for comparison to the model proposed by the river continuum theory. The theory specifies that the biological fauna, physical characteristics and chemical composition observed, are reflected in river order changes in terms of the presence, absence, or density of producer and consumer communities. The study reflected consistencies between the model and observed physical parameters and chemical attributes, but biological indicators were less corroborating. Physical characteristics such as temperature, depth, width, velocity, discharge, and suspended sediments increased with river mile and trends in the data became apparent. Chemical factors such as nitrates, dissolved oxygen, pH, alkalinity, and hardness, though not as clearly conclusive, show a gradient associated with river order transition. Biological indicators were not as conclusive in supporting the river continuum theory since there was no representation of shredders in the headwaters and predatory species were found at most sites. Management issues of the Black River address the control of soil erosion, species composition, and sedimentation as well as maintaining water temperature.http://deepblue.lib.umich.edu/bitstream/2027.42/54342/1/2778.pd

    Impact of misinformation on social media on risk perception in a multi-risk environment

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    Misinformation is not a new phenomenon but, through social media, has gained new dynamics such as the rapidity of spread around the world within a few seconds. Past events have shown that misinformation can worsen the response to an emergency by leading to inappropriate behaviours, triggering fear and anxiety, or reducing the credibility of the measures by official actors. To better understand the dynamics of misinformation on social media or in the press and its effects on people’s beliefs and behaviour, we defined six case studies addressing different hazards and time periods. This allowed us to derive recommendations to prevent and fight the spread of and belief in misinformation along the entire communication chain - source, message, channel, receiver, effect, and feedback. Three of our key results are that: i) official actors should provide information on a regular basis to build credibility and trust, which will allow them to effectively communicate and counter misinformation during emergencies when people are under stressful conditions; ii) fragmented information on social media should be counterbalanced through external links to richer sources, where people can inform themselves about the broader context and details; and iii) the cultural context and ideological debates must be considered to address anchored beliefs and biases when developing strategies to prevent and fight misinformation

    Development of a laser marking system for materials with high sensitive surface

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    With 7 tabs., 2 figs.SIGLETIB: D.Dt.F. AC 1000(27,53) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

    Traceability in Fluorometry - Part I: Physical Standards

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    The inter-instrument, inter-laboratory, and long-term comparability of fluorescence data requires the correction of the measured emission and excitation spectra for the wavelength- and polarization-dependent spectral irradiance of the excitation channel at the sample position and the spectral responsivity of the emission channel employing procedures that guarantee traceability to the respective primary standards. In this respect the traceability chain of fluorometry is discussed from a radiometrists point of view. This involves, in a first step, the realization of the spectral radiance scale, based on the blackbody radiator and electron storage ring, and the spectral responsivity scale, based on the cryogenic radiometer and their control via key comparisons of the national metrology institutes. In a second step, the characterization including state-of-the art uncertainties of the respective source and detector transfer standards such as tungsten strip lamps, integrating sphere radiators, and trap detectors used to disseminate these radiometric quantities to users of spectroscopic techniques is presented

    Approximations to the stochastic Burgers equation

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    This article is devoted to the numerical study of various finite-difference approximations to the stochastic Burgers equation. Of particular interest in the one-dimensional case is the situation where the driving noise is white both in space and in time. We demonstrate that in this case, different finite-difference schemes converge to different limiting processes as the mesh size tends to zero. A theoretical explanation of this phenomenon is given and we formulate a number of conjectures for more general classes of equations, supported by numerical evidence
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