Precrop Functional Group Identity Affects Yield of Winter Barley but Less so High Carbon Amendments in a Mesocosm Experiment

Nitrate leaching is a pressing environmental problem in intensive agriculture. Especially after the crop harvest, leaching risk is greatest due to decomposing plant residues, and low plant nutrient uptake and evapotranspiration. The specific crop also matters: grain legumes and canola commonly result in more leftover N than the following winter crop can take up before spring. Addition of a high carbon amendment (HCA) could potentially immobilize N after harvest. We set up a 2-year mesocosm experiment to test the effects of N fertilization (40 or 160 kg N/ha), HCA addition (no HCA, wheat straw, or sawdust), and precrop plant functional group identity on winter barley yield and soil C/N ratio. Four spring precrops were sown before winter barley (white lupine, faba bean, spring canola, spring barley), which were selected based on a functional group approach (colonization by arbuscular mycorrhizal fungi [AMF] and/or N2-fixing bacteria). We also measured a subset of faba bean and spring barley for leaching over winter after harvest. As expected, N fertilization had the largest effect on winter barley yield, but precrop functional identity also significantly affected the outcome. The non-AMF precrops white lupine and canola had on average a positive effect on yield compared to the AMF precrops spring barley and faba bean under high N (23% increase). Under low N, we found only a small precrop effect. Sawdust significantly reduced the yield compared to the control or wheat straw under either N level. HCAs reduced nitrate leaching over winter, but only when faba bean was sown as a precrop. In our setup, short-term immobilization of N by HCA addition after harvest seems difficult to achieve. However, other effects such as an increase in SOM or nutrient retention could play a positive role in the long term. Contrary to the commonly found positive effect of AMF colonization, winter barley showed a greater yield when it followed a non-AMF precrop under high fertilization. This could be due to shifts of the agricultural AMF community toward parasitism

Fungal Traits Important for Soil Aggregation

Soil structure, the complex arrangement of soil into aggregates and pore spaces, is a key feature of soils and soil biota. Among them, filamentous saprobic fungi have well-documented effects on soil aggregation. However, it is unclear what properties, or traits, determine the overall positive effect of fungi on soil aggregation. To achieve progress, it would be helpful to systematically investigate a broad suite of fungal species for their trait expression and the relation of these traits to soil aggregation. Here, we apply a trait-based approach to a set of 15 traits measured under standardized conditions on 31 fungal strains including Ascomycota, Basidiomycota, and Mucoromycota, all isolated from the same soil. We find large differences among these fungi in their ability to aggregate soil, including neutral to positive effects, and we document large differences in trait expression among strains. We identify biomass density, i.e., the density with which a mycelium grows (positive effects), leucine aminopeptidase activity (negative effects) and phylogeny as important factors explaining differences in soil aggregate formation (SAF) among fungal strains; importantly, growth rate was not among the important traits. Our results point to a typical suite of traits characterizing fungi that are good soil aggregators, and our findings illustrate the power of employing a trait-based approach to unravel biological mechanisms underpinning soil aggregation. Such an approach could now be extended also to other soil biota groups. In an applied context of restoration and agriculture, such trait information can inform management, for example to prioritize practices that favor the expression of more desirable fungal traits

Les enfants de Caïn : la complexité du meurtre dans l’œuvre d’Honoré de Balzac

Lʼœuvre littéraire dʼHonoré de Balzac témoigne dʼune profonde connaissance du système judiciaire et dʼune grande réflexion à son sujet. La violence et le crime, certainement pas les côtés les plus reluisants de lʼHomme, font tout de même partie intégrante de la société. Puisque Balzac a lʼambition de montrer la nature humaine telle quʼelle est, il consent à peindre le meurtre sans euphémismes. Loin de rejeter entièrement lʼesthétique romantique sanglante, il décrit le crime comme une action fondamentalement ambivalente, cʼest-à-dire, quʼil ne le condamne pas absolument ni ne le défend ouvertement. Nous retrouvons dans Balzac ce dont très peu dʼécrivains, et encore moins de philosophes, savent rendre compte : la complexité même de la vie. Lʼengagement social de Balzac invite à penser sa façon de mettre le meurtre en fiction en rapport au contexte sociologique et historique de ses œuvres. Dans la réflexion balzacienne sur le meurtre, quatre thèmes importants reviennent constamment : lʼargent (aspect économique), la jeunesse, la famille (aspects sociaux) et le remords (aspect moral). La dimension philosophique de La Comédie humaine justifie, quant à elle, le choix dʼune lecture également philosophique de lʼœuvre de Balzac. Les meurtres de quatre nouvelles appartenant aux Études philosophiques (El Verdugo, LʼAuberge rouge, Les Marana et Un drame au bord de la mer), assurent une pensée multiple sur des thèmes tels que la justice, le droit, le nom de famille, lʼhonneur, la culpabilité et le glissement dʼune société ancienne vers une société nouvelle dominée par lʼargent.The literary work of Honoré de Balzac testifies to a deep knowledge and reflection of the judicial system. Violence and crime, certainly not the brightest sides of humanity, are nevertheless an integral part of society. Since Balzacʼs ambition is to show human nature as it is, he agrees to depict murder without euphemisms. Far from entirely rejecting the bloody romantic aesthetic, he describes crime as a fundamentally ambivalent action, meaning that he neither absolutely condemns it nor openly defends it. We find in Balzac what very few writers, and even fewer philosophers, can account for : the very complexity of life itself. Balzacʼs social commitment invites us to think about his way of putting murder in fiction in relation to the sociological and historical context of his works. In Balzacʼs reflections on murder, four important themes constantly recur : money (economic aspect), youth, family (social aspects) and remorse (moral aspect). The philosophical dimension of La Comédie humaine justifies the choice of an equally philosophical reading of Balzacʼs work. The murders of four short stories belonging to the Études philosophiques (El Verdugo, LʼAuberge rouge, Les Marana and Un drame au bord de la mer), ensure a multiple reflection on themes such as justice, law, family name, honour, guilt and the shift from an old society to a new money-dominated society

Not Just Pointing: Shannon's Information Theory as a General Tool for Performance Evaluation of Input Techniques

This article was submitted to the ACM CHI conference in September 2017, and rejected in December 2017. It is currently under revision.Input techniques serving, quite literally, to allow users to send information to the computer, the information theoretic approach seems tailor-made for their quantitative evaluation. Shannon's framework makes it straightforward to measure the performance of any technique as an effective information transmission rate, in bits/s. Apart from pointing, however, evaluators of input techniques have generally ignored Shannon, contenting themselves with less rigorous methods of speed and accuracy measurements borrowed from psychology. We plead for a serious consideration in HCI of Shannon's information theory as a tool for the evaluation of all sorts of input techniques. We start with a primer on Shannon's basic quantities and the theoretical entities of his communication model. We then discuss how the concepts should be applied to the input techniques evaluation problem. Finally we outline two concrete methodologies, one focused on the discrete timing and the other on the continuous time course of information gain by the computer

Is the local Hubble flow consistent with concordance cosmology?

Yes. In a perturbed Friedmann model, the difference of the Hubble constants measured in two rest-frames is independent of the source peculiar velocity and depends only on the relative velocity of the observers, to lowest order in velocity. Therefore this difference should be zero when averaging over sufficient sources, which are at large enough distances to suppress local nonlinear inhomogeneity. We use a linear perturbative analysis to predict the Doppler effects on redshifts and distances. Since the observed redshifts encode the effect of local bulk flow due to nonlinear structure, our linear analysis is able to capture aspects of the nonlinear behaviour. Using the largest available distance compilation from CosmicFlows-3, we find that the data is consistent with simulations based on the concordance model, for sources at $20-150\,$Mpc.Comment: 10 pages, 3 figures. Version accepted by JCA

Pour une anthropologie politique de la mer

International audienceThis paper presents an innovative collaborative approach, devoted to strengthening and institutionalization of political anthropology applied to the sea. He first shows what political sciences have to say concerning our understanding of sea management, established to ensure their "sustainability". It then presents the cooperative research structure ApoliMer (political Anthropology of the sea), which address this issue by proposing to grasp the management of coastal and marine "socioecosystems" as a demonstrator of contemporary transformations of politics. Ultimately, it suggests the added value of a stronger link between the human and social sciences and natural sciences, to produce a critical analysis of the categories of thought and action attached to the "systemic management" of the environment.Cet article présente une démarche de recherche collaborative et innovante, consacrée au renforcement et à l'institutionnalisation d'une anthropologie politique de la mer étroitement articulée aux sciences de la nature. Il dit d'abord ce que les sciences sociales du politique ont à apporter à la compréhension de la « gouvernance » de la mer, établie en vue de sa « gestion durable ». Il présente ensuite la structure coopérative de recherche ApoliMer (Anthropologie politique de la mer), qui traite cette question en proposant de faire de la gestion des « socio-écosystèmes » marins et côtiers un démonstrateur des transformations contemporaines du politique. In fine, il laisse entrevoir la plus-value d'une articulation, entre les sciences humaines et sociales et les sciences de la nature pour produire une analyse critique des catégories de pensée et d’action attachées à la «gestion systémique» de l’environnement

Host and abiotic constraints on the distribution of the pine fungal pathogen Sphaeropsis sapinea (= Diplodia sapinea)

Plant fungal pathogens are an increasing emerging threat as climate change progresses. Sphaeropsis sapinea (syn. Diplodia sapinea), the causal fungal agent of Diplodia tip blight, is a major pathogen of pines of forestry and ornamental relevance in Europe and worldwide. Here, we combined molecular-based field surveys in a common-garden setting and across an elevation gradient with historical records, cultivation-based growth experiments and microscopy to report on host and abiotic constraints on the distribution of S. sapinea. Using the arboretum at the Botanical Garden Berlin, Germany, to control for environmental variability, S. sapinea was detected on all seven host Pinus species we studied. However, P. sylvestris is the only species in which the fungus was detected in symptomless needles at the arboretum, and the most frequently recorded host for over a century, suggesting that it is the main, and perhaps, potential original host. In addition, sampling symptomatic needles in four out of the seven same species across a gradient from 200 to 2,100 m of elevation in the French Alps, S. sapinea was not detected at elevation higher than 800 m. Abiotic constraints were also supported by reduced growth of isolates of S. sapinea at low temperature under controlled conditions, but a 35°C prior stress exposure increased the subsequent growth of S. sapinea within its optimal temperature range (20-30°C). Altogether, our study thus not only suggests that S. sapinea is more likely to cause tip blight in P. sylvestris compared to the other species we studied, but also that in the current context of global climate change with predicted temperature increases, the fungus could infect a wider range of pine hosts and locations worldwide

Functional, not Taxonomic, Composition of Soil Fungi Reestablishes to Pre-mining Initial State After 52 Years of Recultivation

Open-cast mining leads to the loss of naturally developed soils and their ecosystem functions and services. Soil restoration after mining aims to restore the agricultural productivity in which the functions of the fungal community play a crucial role. Whether fungi reach a comparable functional state as in the soil before mining within half a century of recultivation is still unanswered. Here, we characterised the soil fungal community using ITS amplicon Illumina sequencing across a 52-year chronosequence of agricultural recultivation after open-cast mining in northern Europe. Both taxonomic and functional community composition showed profound shifts over time, which could be attributed to the changes in nutrient status, especially phosphorus availability. However, taxonomic composition did not reach the pre-mining state, whereas functional composition did. Importantly, we identified a positive development of arbuscular mycorrhizal root fungal symbionts after the initial three years of alfalfa cultivation, followed by a decline after conversion to conventional farming, with arbuscular mycorrhizal fungi being replaced by soil saprobes. We conclude that appropriate agricultural management can steer the fungal community to its functional pre-mining state despite stochasticity in the reestablishment of soil fungal communities. Nonetheless, conventional agricultural management results in the loss of plant symbionts, favouring non-symbiotic fungi

Joint Relay Selection and Power Allocation in Large-Scale MIMO Systems with Untrusted Relays and Passive Eavesdroppers

In this paper, a joint relay selection and power allocation (JRP) scheme is proposed to enhance the physical layer security of a cooperative network, where a multiple antennas source communicates with a single-antenna destination in presence of untrusted relays and passive eavesdroppers (Eves). The objective is to protect the data confidentially while concurrently relying on the untrusted relays as potential Eves to improve both the security and reliability of the network. To realize this objective, we consider cooperative jamming performed by the destination while JRP scheme is implemented. With the aim of maximizing the instantaneous secrecy rate, we derive a new closed-form solution for the optimal power allocation and propose a simple relay selection criterion under two scenarios of non-colluding Eves (NCE) and colluding Eves (CE). For the proposed scheme, a new closed-form expression is derived for the ergodic secrecy rate (ESR) and the secrecy outage probability as security metrics, and a new closed-form expression is presented for the average symbol error rate (SER) as a reliability measure over Rayleigh fading channels. We further explicitly characterize the high signal-to-noise ratio slope and power offset of the ESR to highlight the impacts of system parameters on the ESR. In addition, we examine the diversity order of the proposed scheme to reveal the achievable secrecy performance advantage. Finally, the secrecy and reliability diversity-multiplexing tradeoff of the optimized network are provided. Numerical results highlight that the ESR performance of the proposed JRP scheme for NCE and CE cases is increased with respect to the number of untrustworthy relays.Comment: 18 pages, 10 figures, IEEE Transactions on Information Forensics and Security (In press