Agriculture in a changing climate : Preface

Agriculture is an economic sector that is particularly sensitive to weather. Recent meteorological events have reduced crop production in different parts of the world. Weather extremes resulting from climate change are projected to increase, making crop production more vulnerable and ultimately threatening food security. A continuing effort to develop scientific knowledge in climate and agriculture will help to manage risks and opportunities in these fields. This special issue of Climate Research represents a collection of studies that contribute to the general understanding of weather-related risks and climate impacts on agricultural system

Remote sensing, modelling-based hazard and risk assessment, and management of agro-forested ecosystems

Agricultural and forested landscapes cover large areas over many countries; they are a very important natural resource that needs to be managed sustainably for both the environment and the local communities. Food security, population growth, urbanization, and intensive agricultural development are some of the factors that generate increasing demands for water and land resources in the context of global change. Therefore, potential impacts deriving from a changing climate, from more frequent and intense extreme events, and from anthropogenic activities can pose serious threats to economic infrastructure and development in the coming decades and also severely undermine food, fodder, water, and energy security for a growing global population. Significant recent changes in climate and in the hydrological cycle will impact land suitability for agricultural production and forest ecosystems. In particular, we can expect an increase, in some regions, in the frequency and intensity of extreme weather and weather-related events such as heat waves, floods, wind and snowstorms, droughts, etc. (IPCC, 2012; IPCC, 2021). Furthermore, anthropogenic activities can exacerbate consequences of an unbalanced environment, such as water quality degradation, groundwater depletion, land subsidence, erosion, and sedimentation (Delkash et al., 2018; Tarolli and Straffellini, 2020). Therefore, sustainable management and exploitation of first-order agricultural resources and forested areas, e.g. available land with favourable climate, soil, and water, will become even more important in the lives and activities of people. The 10 original papers included in this special issue address several of these aspects. In particular one review paper provides a general introduction to risk assessment for natural hazards, six papers focus on water- and weather-related hazards (four related to agriculture and two related to water quality at river basin scale), two papers address hazard assessment for the insurance sector, and one paper is related to challenges in agriculture–forest frontiers. The presented researches adopt different types of quantitative and qualitative modelling and spatial analysis and use remote sensing data, when relevant

Simultaneous gas and spray PIV measurements in an optical engine

International audienceEngine internal aerodynamic reveals complex flow involving multi-scale turbulence, flow structure compression, two-phase interactions and are responsible for the mixing process and the engine performance and efficiency. Recent efforts have been made to describe in details in-cylinder flows either with temporal (HR-PIV) or spatial (Tomo-PIV) resolution. However, for gasoline direct injection engine (GDI), the dynamic coupling between gas and spray droplets should also be undertaken for a correct evaluation of in-cylinder aerodynamics. Simultaneous measurements of instantaneous gas and droplets velocities during intake and compression strokes are proposed by means of two-phase PIV based on fluorescence [1, 2]. The technique is adapted to the constraints of optical engine and associated to specific algorithms development for the liquid phase. The engine test bench consists in a mono-cylinder GDI engine (AVL) which operates up to 3000 rpm in optical configuration with a displacement volume of 450 cm 3 and a compression ratio of 8.5. The optical accesses to the combustion chamber is enabled by a quartz-glass liner. The injection system is composed of a solenoid multi-hole injector Bosch fed up by a pressurized volume to ensure a stable injection pressure up to 100 bar. An injector power control module (EFS IPOD) is used to drive the injector and control injection timings in the engine cycle. The two-phase PIV technique is based on the use of two different dyes dissolved in the seeding particle and gasoline, producing fluorescent emissions on separated spectral bands for each phase [1, 2]. The phase separation is enabled by a detection system consisting of a dichroic window distributing the collection signal on two synchronized PIV cameras (Hamamatsu 12 bits 2018×2048 pixels) equipped with Nikkor lenses (50mm f/#2) and adapted pass-band filters. Angular controls are mounted at the base of the dichroic sheet and both cameras in order to adjust with precision the common camera field of view. A refined adjustment based on a polynomial approach of 5 th degree is then numerically performed from calibration grid images to ensure a perfect images overlap and to correct image distortion induced by the glass liner. Dyes excitation is performed with two lasers at different wavelengths (532 nm for the gas and 355 nm for the spray) in order to independently adjust the PIV acquisition delays to the high velocity shift between phases in the early stage of injection. The use of two wavelength also improve the spectral separation of fluorescence signal and then the phase discrimination. An original synchronisation of the laser and camera with the engine cycle is ensured by means of a programmable time board to get rid of engine speed fluctuations and guarantee a fixed working frequency for the lasers while limiting injection and fouling to the acquisition triggering. Velocities of the gas and the liquid phases can thus be acquired simultaneously for engine conditions where the two phases are present, typically early after the start of injection [2, 3]. Prior to the correlation step, a pre-processing of the fluorescence images is performed to enhance the correlation level. A masking technique, with adaptation of the masking surface at each angular position is also used. The PIV post-processing is then adapted to the present configuration with two different algorithms for each phase. The velocity fields of the gaseous phase are obtained by a multi-pass subpixel shift correlation algorithm based on the correlation of the seeding patterns [4]. Interrogation window size of 32×32 pixels (1.85×1.85 mm 2) with an overlap of 50% has been used with a vectors filtering based on a minimum value of the Signal to Noise Rate (SNR) and on a median filter which are adapted to each experimental condition. This enables to reject most of non-valid vectors. Gas phase velocity calculation for internal engine flow is validated in our configuration by means of simultaneous Mie-based PIV and fluorescence based PIV. Comparison of mean and instantaneous velocities show less than 5 % differences. The density of the liquid phase is heterogeneous with a very dense part near the injector nozzle and a dispersed part after the breaking of the liquid sheet. In the spray dispersed part, velocities are processed with a particle approach, whereas in the dense part of the spray, a specific algorithm based on pattern correlation is developed. Preferential direction and topology of the spray are taken into account through the window shape and size

Association of macro-level determinants with adolescent overweight and suicidal ideation with planning: A cross-sectional study of 21 Latin American and Caribbean Countries.

BackgroundAdolescents and young people (10-24 years old) in the Latin America and the Caribbean (LAC) region represent approximately 25% of the region's population. Since the 2008 global economic crisis, the pace of reduction in poverty and income inequality in the LAC region has stalled. The region is characterised by high levels of inequities and is also vulnerable to many natural disasters. Food systems are changing with increased availability and marketing of packaged and fast foods and sugar-sweetened drinks. Adolescence is a formative phase of the life course with multiple physical, emotional and social changes which can make them vulnerable to health problems. We assess the potential impact of macro-determinants, human and economic development as well as income inequality, on 2 top-ranking regional priorities for adolescent nutrition and mental health, using measures of overweight and suicidal ideation and planning which some have shown to be associated.Methods and findingsThe Global School-based Health Survey (GSHS) is a nationally representative self-administered, school-based survey. We examined overweight/obesity and suicidal ideation with planning by gross domestic product (GDP) per capita or human development index (HDI) in 10-19-year-old adolescents from 21 LAC countries between 2009 and 2013. Sample sizes varied from 943 in Anguilla to 27,988 in Argentina. A total of 55,295 adolescents had a measure of overweight/obesity status, and 59,061 adolescents reported about suicidal ideation with planning. There was equal representation by sex in the surveys (52% girls and 48% boys). A total of 28.8% of boys and 28.1% of girls had overweight/obesity, and 7.5% of boys and 17.5% of girls reported suicidal ideation with planning over the last 12 months. Adjusted for individual socioeconomic and risk behaviours, and relative to the highest GDP per capita tertile, the middle tertile was associated with 42% (95% confidence interval (CI) 59% to 17%, p = 0.003) and 32% (95% CI 60% to 5%, p = 0.023), and the lowest tertile with 40% (95% CI 55% to 19%, p = 0.001) and 46% (95% CI 59% to 29%, p ConclusionsThis study shows that economic and human development were positively associated with adolescent overweight/obesity but not with suicidal ideation with planning. We also observed an interconnectedness between overweight/obesity and suicide ideation with planning among girls. These findings highlight the importance of strategies that engage with both upstream and downstream determinants to improve adolescent nutrition and mental health

Status of the light ion source developments at CEA/Saclay

ACC NIMInternational audienceSILHI (High Intensity Light Ion Source) is an ECR ion source producing high intensity proton ordeuteron beams at 95 keV. It is now installed in the IPHI site building, on the CEA/Saclay center. IPHI is a frontend demonstrator of high power accelerator. The source regularly delivers more than 130 mA protons in CWmode and already produced more than 170 mA deuterons in pulsed mode at nominal energy. The last beamcharacterisations, including emittance measurements, space charge compensation analysis and diagnosticimprovements, will be reported. Taking into account the SILHI experience, new developments are in progress tobuild and test a 5 mA deuteron source working in CW mode. This new source will also operate at 2.45 GHz andpermanent magnets will provide the magnetic configuration. This source, of which the design will be discussed,will have to fit in with the SPIRAL 2 accelerator developed at GANIL to produce Radioactive Ion Beams. TheH- test stand status is briefly presented here and detailed in companion papers.This work is partly supported by the European Commission under contract n°: HPRI-CT-2001-50021

Source identification and distribution reveals the potential of the geochemical Antarctic sea ice proxy IPSO25

The presence of a di-unsaturated highly branched isoprenoid (HBI) lipid biomarker (diene II) in Southern Ocean sediments has previously been proposed as a proxy measure of palaeo Antarctic sea ice. Here we show that a source of diene II is the sympagic diatom Berkeleya adeliensis Medlin. Furthermore, the propensity for B. adeliensis to flourish in platelet ice is reflected by an offshore downward gradient in diene II concentration in >100 surface sediments from Antarctic coastal and near-coastal environments. Since platelet ice formation is strongly associated with super-cooled freshwater inflow, we further hypothesize that sedimentary diene II provides a potentially sensitive proxy indicator of landfast sea ice influenced by meltwater discharge from nearby glaciers and ice shelves, and re-examination of some previous diene II downcore records supports this hypothesis. The term IPSO25-Ice Proxy for the Southern Ocean with 25 carbon atoms-is proposed as a proxy name for diene II

<i>Planothidium juandenovense</i> sp. nov. (Bacillariophyta) from Juan de Nova (Scattered Islands, Mozambique Channel) and other tropical environments: a new addition to the <i>Planothidium delicatulum</i> complex

Planothidium juandenovense sp. nov. (Bacillariophyta) is described from the marine tropical environments of Juan de Nova I. (Mozambique Channel), Rodrigues I. (Mascarene Archipelago) and from Guam (Northern Mariana Is., Pacific). This small and relatively rare taxon has short multiseriate striae on the sternum valve (SV), hooked raphe valve (RV) terminal raphe endings and no SV cavum or hoof–shaped area. This taxon has similarities with Planothidium delicatulum (Kütz.) Round et Bukht. and Planothidium septentrionale (Østrup) Round et Bukht. ex Rumrich et al., but also differences: e.g. a relatively narrow and rhombic SV sternum, void of areolae, with vestigial radiate structures and an uninterrupted marginal SV elevated crest or ‘crista marginalis’. P. juandenovense sp. nov. is compared to some other Achnanthales with short SV striae. Cocconeis quarnerensis var. lanceolata Jurilj and Planothidium quarnerense f. rhombica (Giffen) comb. nov. may be close to our new taxon