The Nature of Disconnect: Wilderness in the Face of Climate Change

In the midst of a congressional address on the topic of conservation and restoration, President Lyndon B. Johnson stated, “This generation has altered the composition of the atmosphere on a global scale through . . . a steady increase in carbon dioxide from the burning of fossil fuels.” It was 1965. One year prior, Congress had passed the Wilderness Act of 1964, defining wilderness as “an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.” When the founders of the Wilderness Act wrote these words, they likely had no idea of the repercussions global climate change would bring to these designated areas, even with the issue’s tentative beginnings at the time. They did not understand how an altered atmosphere would threaten the core value of wilderness as untrammeled. Today, half a century later, both these definitions, of climate change and of wilderness, have hardly changed, but the debates surrounding them are vast and heated. Through analysis using existing literature in the fields, I examine the confluence of these two issues, focusing on the history and management of wilderness in the context of anthropogenic climate change. I use this scientific literature along with environmental and philosophical writings and personal experience to help understand the separation society places between wilderness and civilization, reflected in the Wilderness Act, and how that disconnect affects how we approach the issue of climate change

Magnetic and semi-conducting nano-composite films of spinel ferrite and cubic zinc oxide

Magnetic and semi-conducting nano-composite films have been prepared under bias polarization, by radio-frequency sputtering of a pure zinc ferrite target. These composite thin films are made of cubic Zn1 − yFeyO monoxide islands inside a spinel ferrite matrix. The relative proportion of each phase depends on the substrate polarization (i.e. bias power). When no bias is applied the films solely display the diffraction pattern of a spinel phase even if some islands inside the film can be observed by electron microscopy. When the bias power is increased, the spinel phase disappears progressively as enhanced formation of islands takes place in such a manner that the cubic Zn1 − yFeyO monoxide is solely revealed by X-ray diffraction for a bias power higher than 5 W. From bibliographical data and calculated phase diagrams, it can be inferred that these phases would require very low oxygen partial pressure, high temperature and mechanical pressure, to be obtained simultaneously by a conventional ceramic process. This underlines the strong potential of radio-frequency sputtering of oxide targets to prepare original oxides or composite materials

Social Relations in Rural China

The Wu Boliang affair reported in the Chinese media several years ago is symptomatic of the complex socio-political situation in the Chinese countryside. Wu Boliang was one of the first entrepreneurs from his village to develop the cultivation of mandarin oranges, and in 1993 and 1997 he acquired several orchards under the “responsibility system” in order to make them productive with the help of the township. But the latter did not provide him with the necessary funds in time, obliging him to borrow in his own name to cover the wages of the agricultural workers and the purchase of pesticides, fertiliser, etc. As the years went by and debts piled up, the township still did not reimburse him, forcing Wu Boliang to undertake legal proceedings. Although he immediately won his case against the township, the sums owed to him were still not paid, and he had no other option but to become a petitioner. In 2014, 20 years after the signing of the contract, the matter was finally settled. My in-depth analysis follows this particular case over a period of about ten years, and gives a detailed insight into the intricate interplay between the various mechanisms within the hierarchical pyramid of the Chinese society. This enables me to study the behaviour of the agents – both individuals and institutions

On the amplitude of surface waves obtained by noise correlation and the capability to recover the attenuation: a numerical approach

International audienceCross-correlation of ambient seismic noise recorded by a pair of stations is now commonly recognized to contain the Green's function between the stations. Although traveltimes extracted from such data have been extensively used to get images of the Earth interior, very few studies have attempted to exploit the amplitudes. In this work, we investigate the information contained in the amplitudes and we probe the capability of noise correlations to recover anelastic attenuation. To do so, we carry out numerical experiments in which we generate seismic noise at the surface of a 1-D Earth model. One of the advantages of our approach is that both uniform and non-uniform distributions of noise sources can be taken into account. In the case of a uniform distribution, we find that geometrical spreading as well as intrinsic attenuation are retrieved, even after strong non-linear operations such as one-bit normalization and spectral whitening applied to the noise recordings. In the case of a non-uniform distribution of sources, the geometrical spreading of the raw noise correlations depends on the distribution, but intrinsic attenuation is preserved. For the one-bit noise and whitened noise correlations, the interpretation of observed amplitude decays requires further study

A non-periodic two scale asymptotic method to take account of rough topographies for 2D elastic wave propagation

International audienceWe propose a two scale asymptotic method to compute the effective effect of a free surface topography varying much faster than the minimum wavelength for 2-D P-SV elastic wave propagation. The topography variation is assumed to be non-periodic but with a deterministic description and, in this paper, the elastic body below the topography is assumed to be ho- mogeneous. Two asymptotic expansions are used, one in the boundary layer close to the free surface and one in the volume. Both expansions are matched appropriately up to the order 1 to provide an effective topography and an effective boundary condition. We show that the effective topography is not the averaged topography but it is a smooth free surface lying below the fast variations of the real topography. Moreover, the free boundary condition has to be modified to take account of the inertial effects of the fast variations of the topography above the effective topography. In other words, the wave is not propagating in the fast topography but below it and is slowed down by the weight of the fast topography. We present an iterative scheme allowing to find this effective topography for a given minimum wavelength. We do not attempt any mathematical proof of the proposed scheme, nevertheless, numerical tests show good results

Digital Identities and Study Abroad: Teaching Intercultural Competence through Social Media Literacy

Social media platforms are contemporary spaces where selves are revealed and exposed in reciprocity. By imagining digital communication, technology use, and online representation in the same vein as we discuss the experiences of the physical self, the ability to adapt across cultures becomes a skill to hone online as well as in person. As such, digital media is a prime learning tool that practitioners in the field can utilize to reach their target student population no matter their physical location and during each phase of the study abroad process. In this way, study abroad offices can fulfill a mission that goes beyond the logistics of travel in order to concentrate attention on the development of student intercultural competencies

Efficiency of the spectral element method with very high polynomial degree to solve the elastic wave equation

International audienc

Elaboration and characterization of Fe1–xO thin films sputter deposited from magnetite target

Majority of the authors report elaboration of iron oxide thin films by reactive magnetron sputtering from an iron target with Ar–O2 gas mixture. Instead of using the reactive sputtering of a metallic target we report here the preparation of Fe1–xOthin films, directly sputtered froma magnetite target in a pure argon gas flow with a bias power applied. This oxide is generally obtained at very low partial oxygen pressure and high temperature.We showed that bias sputtering which can be controlled very easily can lead to reducing conditions during deposition of oxide thin film on simple glass substrates. The proportion of wustite was directly adjusted bymodifying the power of the substrate polarization. Atomic force microscopy was used to observe these nanostructured layers. Mössbauer measurements and electrical properties versus bias polarization and annealing temperature are also reported

Increasing deletion sizes and the efficiency of CRISPR /Cas9‐mediated mutagenesis by SunTag ‐mediated TREX1 recruitment

Previously, it has been shown that mutagenesis frequencies can be improved by directly fusing the human exonuclease TREX2 to Cas9, resulting in a strong increase in the frequency of smaller deletions at the cut site. Here, we demonstrate that, by using the SunTag system for recruitment of TREX2, the mutagenesis efficiency can be doubled in comparison to the direct fusion in Arabidopsis thaliana. Therefore, we also tested the efficiency of the system for targeted deletion formation by recruiting two other 3′-5′ exonucleases, namely the human TREX1 and E. coli ExoI. It turns out that SunTag-mediated recruitment of TREX1 not only improved the general mutation induction efficiency slightly in comparison to TREX2, but that, more importantly, the mean size of the induced deletions was also enhanced, mainly via an increase of deletions of 25 bp or more. EcExoI also yielded a higher amount of larger deletions. However, only in the case of TREX1 and TREX2, the effect was predominately SunTag-dependent, indicating efficient target-specific recruitment. Using SunTag-mediated TREX1 recruitment at other genomic sites, we were able to obtain similar deletion patterns. Thus, we were able to develop an attractive novel editing tool that is especially useful for obtaining deletions in the range from 20 to 40 bp around the cut site. Such sizes are often required for the manipulation of cis-regulatory elements. This feature is closing an existing gap as previous approaches, based on single nucleases or paired nickases or nucleases, resulted in either shorter or longer deletions, respectively

1-D non periodic homogenization for the seismic wave equation

International audienceWhen considering numerical acoustic or elastic wave propagation in media containing small heterogeneities with respect to the minimum wavelength of the wavefield, being able to upscale physical properties (or homogenize them) is valuable mainly for two reasons. First, replacing the original discontinuous and very heterogeneous medium by a smooth and more simple one, is a judicious alternative to the necessary fine and difficult meshing of the original medium required by many wave equation solvers. Second, it helps to understand what properties of a medium are really ‘seen' by the wavefield propagating through, which is an important aspect in an inverse problem approach. This paper is an attempt of a pedagogical introduction to non- periodic homogenization in 1-D, allowing to find the effective wave equation and effective physical properties, of the elastodynamics equation in a highly heterogeneous medium. It can be extrapolated from 1-D to a higher space dimensions. This development can be seen as an extension of the classical two-scale homogenization theory applied to the elastic wave equation in periodic media, with this limitation that it does not hold beyond order 1 in the asymptotic expansion involved in the classical theory