Humanitarian inversions:COVID-19 as crisis

COVID-19 is a multi-spectral crisis that has added an acute layer over a panoply of complex emergencies across the world. In the process, it has not only exposed actually-existing emergencies, but also exacerbated them as the global gaze has turned inward. As a crisis, COVID-19 straddles and challenges the boundaries between humanitarianism, development, and global health—the frames and categories through which emergencies are so often understood and intervened upon. Reflection on these fundamental categories is, we argue, an important geographical endeavour. Drawing on Geoffrey Bowker's analytical lens of the ‘infrastructural inversion’, we explore how humanitarianism has been upended by COVID-19 along two axes that are of core concern to geographers: (1) the spatial and (2) the temporal. We first contextualise current debates on the humanitarian endeavour and its future within recent geographical research. We then set out the complex structure by which COVID-19 has been both imagined and intervened upon as a humanitarian emergency. In so doing, we then pave the way for a deeper empirical analysis of the spatial and temporal inversions that have been brought forth by COVID-19. The paper concludes by examining the conceptual value of the ‘inversion’ in developing geographical research agendas better attuned to the increasing porosity of humanitarianism, development, and global health.</p

Holographic Lithography

This review summarises the work of the Durham-Sheffield, UK team working on Holographic Lithography over the last decade. It collates progress in 3D resolution and overall scale of the substrate wiring patterns designed and considers a range of approaches and applications

Superconductivity Induced by Bond Breaking in the Triangular Lattice of IrTe2

IrTe2, a layered compound with a triangular iridium lattice, exhibits a structural phase transition at approximately 250 K. This transition is characterized by the formation of Ir-Ir bonds along the b-axis. We found that the breaking of Ir-Ir bonds that occurs in Ir1-xPtxTe2 results in the appearance of a structural critical point in the T = 0 limit at xc = 0.035. Although both IrTe2 and PtTe2 are paramagnetic metals, superconductivity at Tc = 3.1 K is induced by the bond breaking in a narrow range of x > xc in Ir1-xPtxTe2. This result indicates that structural fluctuations can be involved in the emergence of superconductivity.Comment: 10 pages, 4 figure

Innovation et gouvernance territoriale : une analyse par les dispositifs

International audienceCette communication vise à présenter les outils méthodologiques d'analyse/évaluation de la gouvernance territoriale élaborés dans le cadre du projet de recherche PSDR Gouv.Innov sur les innovations organisationnelles relatives à la gouvernance territoriale. Il s'agit d'étudier les transformations introduites par les politiques de développement durable au niveau des dispositifs de gouvernance territoriale visant à favoriser une gestion intégrée des espaces ruraux. Dans un contexte de recomposition de l'action publique où les procédures d'aménagement sont plutôt normées par des représentations urbaines, l'accent est mis sur la question des modalités de représentation des activités rurales, pour lesquelles nous faisons l'hypothèse qu'elles sont sous représentées. Les premiers résultats méthodologiques permettent, dans une première partie, de proposer une définition générique et pragmatique de la gouvernance territoriale et de préciser la notion de dispositifs de gouvernance comme objet d'observation. A partir de cette définition une grille d'analyse permettant d'appréhender l'ensemble des dimensions en jeu dans les processus de gouvernance territoriale est élaborée. Dans la deuxième partie nous explorons l'intérêt de la notion de dispositif pour observer les processus de gouvernance et proposons une grille de collecte et de structuration des informations pour constituer des chroniques des dispositifs étudiés. / This paper seeks to present the methodological tools used in the analysis/evaluation of territorial governance developed during research undertaken within the framework of the PSDR Gouv-Innov project on organisational innovations with respect to territorial governance. It involves the study of the changes resulting from the emergence of sustainable development policies in territorial governance systems aiming to implement the integrated management of rural areas. In a context of changes in the way in which public action is implemented (for instance, public-private partnerships), where development procedures are usually standardised by urban representations, the emphasis is placed on the issue of the representation of rural activities, the hypothesis being that they are under-represented. The initial methodological results lead, in the first instance, to a proposition for a generic and pragmatic definition of territorial governance and a clarification of the notion of governance systems as objects of observation. This definition can be used as the basis of a framework to address all the analytical dimensions of the territorial governance process. In the second part, the authors explore the idea of system in order to observe governance processes and suggest a matrix for the collection and structuring of information in order to report on the studied systems

Joint PDF modelling of turbulent flow and dispersion in an urban street canyon

The joint probability density function (PDF) of turbulent velocity and concentration of a passive scalar in an urban street canyon is computed using a newly developed particle-in-cell Monte Carlo method. Compared to moment closures, the PDF methodology provides the full one-point one-time PDF of the underlying fields containing all higher moments and correlations. The small-scale mixing of the scalar released from a concentrated source at the street level is modelled by the interaction by exchange with the conditional mean (IECM) model, with a micro-mixing time scale designed for geometrically complex settings. The boundary layer along no-slip walls (building sides and tops) is fully resolved using an elliptic relaxation technique, which captures the high anisotropy and inhomogeneity of the Reynolds stress tensor in these regions. A less computationally intensive technique based on wall functions to represent boundary layers and its effect on the solution are also explored. The calculated statistics are compared to experimental data and large-eddy simulation. The present work can be considered as the first example of computation of the full joint PDF of velocity and a transported passive scalar in an urban setting. The methodology proves successful in providing high level statistical information on the turbulence and pollutant concentration fields in complex urban scenarios.Comment: Accepted in Boundary-Layer Meteorology, Feb. 19, 200

Connecting spatial and frequency domains for the quaternion Fourier transform

The quaternion Fourier transform (qFT) is an important tool in multi-dimensional data analysis, in particular for the study of color images. An important problem when applying the qFT is the mismatch between the spatial and frequency domains: the convolution of two quaternion signals does not map to the pointwise product of their qFT images. The recently defined ‘Mustard’ convolution behaves nicely in the frequency domain, but complicates the corresponding spatial domain analysis. The present paper analyses in detail the correspondence between classical convolution and the new Mustard convolution. In particular, an expression is derived that allows one to write classical convolution as a finite linear combination of suitable Mustard convolutions. This result is expected to play a major role in the further development of quaternion image processing, as it yields a formula for the qFT spectrum of the classical convolution

Development of a few TW Ti:Sa laser system at 100 Hz for proton acceleration

[EN] We report the development of a table-top high peak power Titanium:Sapphire (Ti:Sa) CPA laser working at 100 Hz capable of delivering 205 mJ, 55 fs pulses. Every amplification stage is pumped by Nd-doped solid-state lasers and fully powered by diodes. Thermal effects in the Ti:Sa amplifiers are compensated passively with optics. This system is intended to be used for proton acceleration experiments at high repetition rates.Centro para el Desarrollo Tecnológico Industrial (CDTI, Spain) within the INNPRONTA program, Grant no. IPT-20111027.Lera, R.; Bellido-Millán, PJ.; Sánchez, I.; Mur, P.; Seimetz, M.; Benlloch Baviera, JM.; Roso, L.... (2019). Development of a few TW Ti:Sa laser system at 100 Hz for proton acceleration. Applied Physics B. 125(1):1-8. https://doi.org/10.1007/s00340-018-7113-8S181251P. Zeitoun, G. Faivre, S. Sebban, T. Mocek, A. Hallou, M. Fajardo, D. Aubert, P. Balcou, F. Burgy, D. Douillet, S. Kazamias, G. de Lachèze-Murel, T. Lefrou, S. le Pape, P. Mercère, H. Merdji, A.S. Morlens, J.P. Rousseau, C. Valentin, Nature 431(7007), 426–429 (2004)V. Malka, S. Fritzler, E. Lefebvre, M.-M. Aleonard, F. Burgy, J.-P. Chambaret, J.-F. Chemin, K. Krushelnick, G. Malka, S.P.D. Mangles, Z. Najmudin, M. Pittman, J.-P. Rousseau, J.-N. Scheurer, B. Walton, A.E. Dangor, Science 298(5598), 1596–1600 (2002)H. Daido, M. Nishiuchi, A.S. Pirozhkov, Rep. Progress Phys. 75(5), 056401 (2012)A. Macchi, M. Borghesi, M. Passoni, Rev. Mod. Phys. 85, 751–793 (2013)T. Tajima, J.M. Dawson, Phys. Rev. Lett. 43, 267–270 (1979)M. Noaman-ul Haq, H. Ahmed, T. Sokollik, L. Yu, Z. Liu, X. Yuan, F. Yuan, M. Mirzaie, X. Ge, L. Chen, J. Zhang, Phys. Rev. Accel. Beams 20, 041301 (2017)D. Strickland, G. Mourou, Opt. Commun. 53(3), 219–221 (1985)G. Cheriaux, B. Walker, L.F. Dimauro, P. Rousseau, F. Salin, J.P. Chambaret, Opt. Lett. 21(6), 414–416 (1996)P. Tournois, Opt. Commun. 140(4), 245–249 (1997)R. Soulard, A. Brignon, S. Raby, E. Durand, R. Moncorgé, Appl. Phys. B 106(2), 295–300 (2012)J. Liu, L. Ge, L. Feng, H. Jiang, H. Su, T. Zhou, J. Wang, Q. Gao, J. Li, Chin. Opt. Lett. 14(5), 051404 (2016)A. Maleki, M.K. Tehrani, H. Saghafifar, M.H.M. Dindarlu, H. Ebadian, Laser Phys. 26(2), 025003 (2016)R. Lera, F. Valle-Brozas, S. Torres-Peiró, A.R. de-la Cruz, M. Galán, P. Bellido, M. Seimetz, J.M. Benlloch, L. Roso, Appl. Opt. 55(33), 9573–9576 (2016)R. Lausten, P. Balling, J. Opt. Soc. Am. B 20(7), 1479–1485 (2003)I. Nam, M. Kim, T.H. Lee, S.W. Lee, H. Suk, Curr. Appl. Phys. 15(4), 468–472 (2015)E. Treacy, IEEE J. Quantum Electron. 5(9), 454–458 (1969)A. Trisorio, S. Grabielle, M. Divall, N. Forget, C.P. Hauri, Opt. Lett. 37(14), 2892–2894 (2012)Y.-H. Cha, Y.-W. Lee, S.M. Nam, J.M. Han, Y.J. Rhee, B.D. Yoo, B.C. Lee, Y.U. Jeong, Appl. Opt. 46(28), 6854–6858 (2007)P. Bellido, R. Lera, M. Seimetz, A.R. de la Cruz, S. Torres-Peiró, M. Galán, P. Mur, I. Sánchez, R. Zaffino, L. Vidal, A. Soriano, S. Sánchez, F. Sánchez, M. Rodríguez-Álvarez, J. Rigla, L. Moliner, A. Iborra, L. Hernández, D. Grau-Ruiz, A. González, J. García-Garrigos, E. Díaz-Caballero, P. Conde, A. Aguilar, L. Roso, J. Benlloch, J. Instrum. 12(05), T05001 (2017

A versatile Plasmodium falciparum reporter line expressing NanoLuc enables highly sensitive multi-stage drug assays

Presentation of a versatile Plasmodium falciparum dual reporter line, expressing both a fluorescent protein and NanoLuc under a constitutive promoter, that can be used to screen for novel anti-malarial drugs effective against multiple stages of the parasite.Transgenic luciferase-expressing Plasmodium falciparum parasites have been widely used for the evaluation of anti-malarial compounds. Here, to screen for anti-malarial drugs effective against multiple stages of the parasite, we generate a P. falciparum reporter parasite that constitutively expresses NanoLuciferase (NanoLuc) throughout its whole life cycle. The NanoLuc-expressing P. falciparum reporter parasite shows a quantitative NanoLuc signal in the asexual blood, gametocyte, mosquito, and liver stages. We also establish assay systems to evaluate the anti-malarial activity of compounds at the asexual blood, gametocyte, and liver stages, and then determine the 50% inhibitory concentration (IC50) value of several anti-malarial compounds. Through the development of this robust high-throughput screening system, we identify an anti-malarial compound that kills the asexual blood stage parasites. Our study highlights the utility of the NanoLuc reporter line, which may advance anti-malarial drug development through the improved screening of compounds targeting the human malarial parasite at multiple stages.Host-parasite interactio

Regulation of N-WASP and the Arp2/3 Complex by Abp1 Controls Neuronal Morphology

Polymerization and organization of actin filaments into complex superstructures is indispensable for structure and function of neuronal networks. We here report that knock down of the F-actin-binding protein Abp1, which is important for endocytosis and synaptic organization, results in changes in axon development virtually identical to Arp2/3 complex inhibition, i.e., a selective increase of axon length. Our in vitro and in vivo experiments demonstrate that Abp1 interacts directly with N-WASP, an activator of the Arp2/3 complex, and releases the autoinhibition of N-WASP in cooperation with Cdc42 and thereby promotes N-WASP-triggered Arp2/3 complex-mediated actin polymerization. In line with our mechanistical studies and the colocalization of Abp1, N-WASP and Arp2/3 at sites of actin polymerization in neurons, we reveal an essential role of Abp1 and its cooperativity with Cdc42 in N-WASP-induced rearrangements of the neuronal cytoskeleton. We furthermore show that introduction of N-WASP mutants lacking the ability to bind Abp1 or Cdc42, Arp2/3 complex inhibition, Abp1 knock down, N-WASP knock down and Arp3 knock down, all cause identical neuromorphological phenotypes. Our data thus strongly suggest that these proteins and their complex formation are important for cytoskeletal processes underlying neuronal network formation