The role of geomorphic controls on the development of defensive networks along the Western Front during the Great War: case study of Champagne and Argonne (france)

The Great War was marked on the western front mainly by a war of position (for 40 out of the 51 months of the conflict) along the 750 km of the front area from Flanders to Alsace. The objective of this article is to understand the spatial organisation of defence networks in the eastern part of the Champagne region (Champagne sèche), the Vallage d’Aisne and in the Argonne region in 1918 by means of an analysis of geographical information system (GIS)-processed trench maps. This article presents a methodology, involving the transfer of fire trenches, communication trenches and vegetation, integrated into a geodatabase, and then cross-referenced with the digital terrain model (DTM). This comparison of three distinct regions with a chalky plateau (Champagne sèche), a wet plain (Vallage d’Aisne) and a sandy plateau covered with forests (Argonne), not only makes it possible to qualify the role of geographical conditions on the Great War but also to quantify the defence networks.Keywords: WW1, trench map, GIS, spatial analysis, Champagne sèche, Vallage d’Aisne, Argonn

Hypersound damping in vitreous silica measured by picosecond acoustics

The attenuation of longitudinal acoustic phonons up to frequencies nearing 250 GHz is measured in vitreous silica with a picosecond optical technique. Taking advantage of interferences on the probe beam, difficulties encountered in early pioneering experiments are alleviated. Sound damping at 250 GHz and room temperature is consistent with relaxation dominated by anharmonic interactions with the thermal bath, extending optical Brillouin scattering data. Our result is at variance with claims of a recent deep-UV experiment which reported a rapid damping increase beyond 100 GHz. A comprehensive picture of the frequency dependence of sound attenuation in $v$-SiO$_2$ can be proposed.Comment: 4 pages, 3 figure

Engagement on risk assessment for gene drive mosquitoes by EFSA and Target Malaria

This is the final version. Available on open access from Elsevier via the DOI in this recordData availability: No data was used for the research described in the article.As engineered gene drive technologies continue to advance, many actors are actively considering how environmental risk assessments (RAs) for gene drive organisms should be conducted, and how stakeholder engagement opportunities should be provided. There is, however, a lack of clarity concerning what constitutes engagement on gene drive RA and, furthermore, what forms of engagement already exist around gene drive RA. To address this gap, we reflect on the actions of a risk assessor (the European Food Safety Authority, EFSA) and a gene drive developer (Target Malaria) to understand: 1) the RA-related decisions that each are making concerning gene drive technology for mosquitoes and other harmful insects, 2) the existing role of engagement in those decisions, and 3) the implications for our understandings of engagement and RA. We found, first, that both EFSA and Target Malaria have already made many RA-related decisions, even though any preparation and evaluation of a formal RA for gene drive mosquitoes remains far off. This finding supports the idea that gene drive RA involves multiple processes and decisions in different forms across the entire technology and regulatory development process. Second, we found that both EFSA and Target Malaria have already integrated engagement into their respective RA-related decisions in different ways, reflecting their different roles. We conclude by considering how EFSA and Target Malaria could improve their existing RA-related engagement by explicitly considering disciplinary diversity and worldview diversity in their related decision making.British AcademyBill and Melinda Gates Foundatio

Electric-Field-Induced Mott Insulating States in Organic Field-Effect Transistors

We consider the possibility that the electrons injected into organic field-effect transistors are strongly correlated. A single layer of acenes can be modelled by a Hubbard Hamiltonian similar to that used for the kappa-(BEDT-TTF)(2)X family of organic superconductors. The injected electrons do not necessarily undergo a transition to a Mott insulator state as they would in bulk crystals when the system is half-filled. We calculate the fillings needed for obtaining insulating states in the framework of the slave-boson theory and in the limit of large Hubbard repulsion, U. We also suggest that these Mott states are unstable above some critical interlayer coupling or long-range Coulomb interaction.Comment: 9 pages, 7 figure

Improper colourings inspired by Hadwiger’s conjecture

Hadwiger’s Conjecture asserts that every Kt-minor-free graph has a proper (t − 1)-colouring. We relax the conclusion in Hadwiger’s Conjecture via improper colourings. We prove that every Kt-minor-free graph is (2t − 2)-colourable with monochromatic components of order at most 1/2 (t − 2). This result has no more colours and much smaller monochromatic components than all previous results in this direction. We then prove that every Kt-minor-free graph is (t − 1)-colourable with monochromatic degree at most t − 2. This is the best known degree bound for such a result. Both these theorems are based on a decomposition method of independent interest. We give analogous results for Ks,t-minorfree graphs, which lead to improved bounds on generalised colouring numbers for these classes. Finally, we prove that graphs containing no Kt-immersion are 2-colourable with bounded monochromatic degree

Density and distribution of western chimpanzees around a bauxite deposit in the Boé Sector, Guinea-Bissau

Funding: partial support by CEAUL (funded by FCT - Fundação para a Ciência e a Tecnologia, Portugal, through the project UID/MAT/00006/2019) (TAM).The Boé sector in southeast Guinea‐Bissau harbors a population of western chimpanzees (Pan troglodytes verus) that inhabits a mosaic of forest and savanna. The Boé sector contains a substantial bauxite deposit in a region called Ronde Hill, and there are plans for the construction of a mine, which may endanger the chimpanzee population. In 1‐week survey in May 2013, we used the standing crop nest counts method to obtain the number of chimpanzee nests and from that estimate the density and abundance of chimpanzees. We carried out five 1‐km line transects that covered the bauxite deposit and surrounding valleys. We used density surface modeling to analyze habitat preferences, then predicted chimpanzee nest density and distribution based on environmental variables. We found the projected location of the mine partially coincides with an area of high predicted abundances of chimpanzee nests and is surrounded by highly suitable areas for chimpanzees (northeast and southwest). We conclude the mine could have significant direct and indirect effects on this population of chimpanzees whose impacts must be carefully considered and properly mitigated if the mine is built.PostprintPeer reviewe

The influence of distributed leadership on teachers' organizational commitment: a multilevel approach

In the present study the effects of a cooperative leadership team, distributed leadership, participative decision-making, and context variables on teachers' organizational commitment are investigated. Multilevel analyses on data from 1522 teachers indicated that 9% of the variance in teachers' organizational commitment is attributable to differences between schools. The analyses revealed that especially the presence of a cooperative leadership team and the amount of leadership support played a significantly positive key role in predicting teachers' organizational commitment. Also, participative decision-making and distribution of the supportive leadership function had a significant positive impact on teachers' organizational commitment. In contrast, distribution of the supervisory leadership function and teachers' job experience had a significant negative impact

The relation between school leadership from a distributed perspective and teachers' organizational commitment: examining the source of the leadership function

Purpose: In this study the relationship between school leadership and teachers’ organizational commitment is examined by taking into account a distributed leadership perspective. The relation between teachers’ organizational commitment and contextual variables of teachers’ perceptions of the quality and the source of the supportive and supervisory leadership function, participative decision making, and cooperation within the leadership team are examined. Research Design: A survey was set up involving 1,522 teachers from 46 large secondary schools in Flanders (Belgium). Because the data in the present study have an inherent hierarchical structure, that is, teachers are nested into schools, hierarchical linear modeling techniques are applied. Findings: The analyses reveal that 9% of the variance in teachers’ organizational commitment is attributable to differences between schools. Teachers’ organizational commitment is mainly related to quality of the supportive leadership, cooperation within the leadership team, and participative decision making. Who performed the supportive leadership function plays only a marginally significant positive role. The quality of the supervisory leadership function and the role of the leadership team members in this function were not significantly related to teachers’ organizational commitment. Conclusions: The implications of the findings are that to promote teachers’ organizational commitment teachers should feel supported by their leadership team and that this leadership team should be characterized by group cohesion, role clarity, and goal orientedness. Recommendations for further research are provided

Cytomolecular identification of individual wheat-wheat chromosome arm associations in wheat-rye hybrids

Chromosome pairing in the meiotic metaphase I of wheatrye hybrids has been characterized by sequential genomic and fluorescent in situ hybridization allowing not only the discrimination of wheat and rye chromosomes, but also the identification of the individual wheat and rye chromosome arms involved in the chromosome associations. The majority of associations (93.8%) were observed between the wheat chromosomes. The largest number of wheat-wheat chromosome associations (53%) was detected between the A and D genomes, while the frequency of B-D and A-B associations was significantly lower (32 and 8%, respectively). Among the A-D chromosome associations, pairing between the 3AL and 3DL arms was observed with the highest frequency, while the most frequent of all the chromosome associations (0.113/ cell) was found to be the 3DS-3BS. Differences in the pairing frequency of the individual chromosome arms of wheat-rye hybrids have been discussed in relation to the homoeologous relationships between the constituent genomes of hexaploid wheat