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COVID-19 pandemic exacerbated food insecurity in South American countries

Food Security 2025年 1-22页

作者： Vasconcelos-Neto, Carlos Frederico A. Jacob, Michelle Tregidgo, Daniel Valle, Denis El bizri, Hani R. Gomes, Sávio Marcelino Fa, Julia E. Morcatty, Thais Q. Monteiro, Frederico Ozanan barros Scofield, Alessandra Matte, Alessandra Chaves, Willandia A. borges, Luiz Henrique Medeiros Silva, Antônia I. A. Santos-Fita, Dídac Silva, Tiago Lucena Lopes-Filho, Isaac Ibernon Silva, Maria Isabel Afonso barreto, Rebeca Mascarenhas Fonseca Oliveira, Marcela A Ferreira, Felipe Silva Santos, Ricardo Rodrigues Honorato-Júnior, Jaime brazil, Marilene Vasconcelos Silva Sousa, Shirliane Araújo Oliveira, Deise C. L. Ferreira, Valéria R. F. Soares, Hyago K. L. Pinto, Marcia F. beltrão-Mendes, Raone Rodrigues, Marcos Paulo Lopes Rocha, Wáldima Alves Gutiérrez Poblete, Roberto Schettini, Francisco Luigi Rojas, Joe S. S. Aspilcueta, Marco A. Zevallos, Justo D. V. Gagliardi-Urrutia, Giussepe Menéndez Delgado, Erick Rodolfo Polit-Vera, Mariela Lissette Rodríguez Ríos, Elvira Carrascal Velásquez, Juan Carlos Forlano Riera, Maria Dalila Perera Romero, Lucy Salas Dueñas, Danilo A. Garin, Daniel Mayor, Pedro Instituto de Desenvolvimento Sustentável Mamirauá GP Ecologia de Vertebrados Terrestres Estrada do Bexiga Amazonas Tefé 258469553 - 225 Brazil Calle Enrique Granados 30 Boadilla del Monte Madrid 28660 Spain Departamento de Saúde Coletiva e Nutrição Centro de Ciências da Saúde Universidade Federal do Rio Grande do Norte Lagoa Nova Rio Grande do Norte Natal 59075000 Brazil University of Florida Gainesville 32611 FL United States School of Science Engineering and Environment University of Salford 43 Crescent Salford M5 4 WT United Kingdom Center for International Forestry Research - CIFOR Bogor Indonesia Department of Nutrition Centre of Health Sciences Universidade Federal da Paraíba R. Tabeliao Estanislau Eloy S/N Paraiba João Pessoa 58050585 Brazil Natural Sciences Faculty of Science and Engineering Manchester Metropolitan University Chester Street Manchester M15 6BH United Kingdom Natural Sciences and Environment Research Hub University of Gibraltar Gibraltar Gibraltar Department of Geography University College London North West Wing Gower Street London WC1E 6BT United Kingdom Institute of Health and Animal Production Federal Rural University of the Amazon Av. Presidente Tancredo Neves 2501 Pará Belém 66077 - 830 Brazil Laboratory of Animal Health Postgraduate Program in Animal Health in the Amazon Institute of Veterinary Medicine Federal University of Pará Universidade Federal do Pará (UFPA) BR 316 Km 61 s/n bairro Saudade II Pará Castanhal 68746360 Brazil Programa de Pós-Graduação Em Agroecossistemas (PPGSI) Universidade Tecnológica Federal Do Paraná (UTFPR) Prolongamento da Rua Cerejeiras S/N Paraná Santa Helena 85892000 Brazil Department of Fish and Wildlife Conservation Virginia Polytechnic Institute and State University 310 West Campus Drive Blacksburg 24061 VA United States Associação SOS Amazônia Rua Pará 61 Acre Rio Branco 69905082 Brazil Universidade Federal do Amazonas Instituto Natureza e Cultura Rua 1º de Mai

The COVID-19 pandemic triggered unparalleled political, economic, and social ramifications, exacerbating global food insecurity (FI). To understand the overall impact of the pandemic and how different socio-economic groups were affected, we assessed prevalence and severity of FI in a sample of 18,997 households across seven countries in South America. We employed the Food Insecurity Experience Scale developed by the FAO. Our results showed that pre-pandemic, 4.5% of the sampled population across the entire continent faced Moderate FI, while 0.6% experienced severe FI. During the pandemic, Moderate FI increased to 16.9% (+ 12.4%), and Severe FI to 2.7% (+ 2.1%). by country, pre-pandemic households in Venezuela had the highest prevalence of Moderate FI (9.7%), with Peru experiencing the highest Severe FI frequency (1.1%). Peru had the greatest rise in Moderate (+ 23.9%) and Severe FI (+ 4.6%) during the pandemic. Low-income households, defined as those earning < 2 minimum wages per month, were most susceptible to FI. Uruguayan low-income families exhibited the most significant rise (+ 40.4%) in Moderate FI, while those in Peru experienced an increase of + 9.1% in Severe FI. This study measures the profound and far-reaching impact of the COVID-19 pandemic on FI in South America. Our findings also emphasise the critical importance of implementing effective public policy interventions to improve resilience against future shocks. This would enable policymakers to develop targeted strategies that address the immediate challenges posed by pandemics as well as laying the groundwork for a more resilient and sustainable food security landscape in the region. © The Author(s) 2025.

关键词： Covid-19 Food security Hunger Nutrition South America

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The effect of voids on transverse cracking in composite laminates as revealed by combined computational analysis at the micro- and meso-levels 21

The effect of voids on transverse cracking in composite lami...

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21st International Conference on Composite materials, ICCM 2017

作者： Mehdikhani, Mahoor Petrov, Nikolay Melro, António R. Lomov, Stepan V. Gorbatikh, Larissa KU Leuven Department of Materials Engineering Kasteelpark Arenberg 44 Leuven3001 Belgium SIM M3 program Technologiepark 935 ZwijnaardeB-9052 Belgium Center for Design Manufacturing and Materials Skolkovo Institute of Science and Technology Skolkovo Innovation Center Nobel St. 3 Moscow143026 Russia University of Bristol Bristol United Kingdom

An extensive amount of experimental research on voids and their effects on mechanical properties of composite materials has been performed over the years. However, fewer studies have tried to investigate these effects through computational modeling. The scale issue is one of the reasons. Intra-laminar voids are defects that have microscopic features and interact with other micro-heterogeneities like fibers, and at the same time they influence the behavior of composites at the ply and laminate levels (referred here as the meso-level). Prediction of their effects on statistically-controlled properties, such as transverse cracking, requires a multiscale modeling approach. In the present study, a methodology is proposed, in which the micro-scale effect of voids on transverse strength of fiber-reinforced composites is evaluated through computational micromechanics. The results are then transferred to a ply-level model as input parameters to investigate the influence of voids on transverse cracking of a cross-ply composite laminate. Through this methodology, the influence of void size on the evolution of crack density in function of the applied strain can be modeled in a macro-level specimen at a manageable computational cost. The results show strong influence of voids on transverse cracking. They also reveal that the developed two-level methodology is a promising technique to evaluate this influence. © 2017 International Committee on Composite materials. All rights reserved.

关键词： EXtended finite element method (XFEM) Multiscale modeling Transverse cracking Voids

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Chemical Composition,Antioxidant and Antimicrobial Activity of the Oil and Plant Extract Myrocarpus frondosus Allemao

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American Journal of Plant sciences 2017年第7期8卷 1560-1571页

作者： Ivandra Ignês de Santi Darci Alberto Gatto Miriam Ribeiro Galvao Machado Patrícia Soares bilhalva dos Santos Rogerio Ant?nio Freitag Natural Products Research Laboratory Graduate Program in Biochemistry and Bioprospecting Federal University of Pelotas Pelotas Brasil Postgraduate Program Materials Science and Engineering Federal University of Pelotas Pelotas Brasil Center for Chemical Sciences Pharmaceutical and Food Federal University of Pelotas Pelotas Brasil Chemical and Environmental Engineering Department University of the Basque Country (UPV/EHU) San Sebastian Spain

The objective of this study was to evaluate the chemical profile of extracts (aqueous and ethanol) and the essential oil of Myrocarpus frondosus Allem?o, the sensitivity of strains of Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Listéria monocytogenes, front the extracts and essential oil, by means of the microdilution method in broth, the antioxidant activity by the AbTS method, and the content of phenolic compounds present in the extracts and oil. For the preparation of extracts from plant leaves used with ethanol and water, then separated, the chemical identification of compounds was performed by high-performance liquid chromatography (CLAE-DAD) and gas chromatography coupled to mass spectrum (CG/MS). With the chemical analysis of the extracts obtained the presence of the major compound rutin, and oil major compound was found germacrene b. In the microdilution method in broth, oil and extracts showed inhibition against all the bacteria tested in the concentrations 1 mg/ml to 0.25 mg/ml, except for Staphylococcus aureus at a concentration of 0.25 mg/ml of the essential oil and trans-caryophyllene. The results of Minimum bactericidal Concentration showed that the essential oil had bactericidal activity at a concentration of 1mg/ml for all bacteria tested and trans-caryophyllene at the same concentration only for Listeria monocytogenes. In relation to the essential oil, antioxidant activity showed higher radical reduction capacity of 40.92% and the content of phenolic compounds ethanol extract showed more 12.72%. The in vitro results support the conclusion that the essential oil is very promising both in antimicrobial action as antioxidant activity and the leaf extracts on antioxidant activity.

关键词： Myrocarpus frondosus Allemao Antimicrobial Antioxidant

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Phase and crystallite size analysis of (Ti1-xMox)C-(Ni,Cr) cermet obtained by mechanical alloying

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AIP Conference Proceedings 2018年第1期1945卷

作者： Suryana Muhammad Anis Azwar Manaf 1Materials Science Postgraduate Program Physics Department Universitas Indonesia Jl. Salemba Raya No.4 Jakarta 10430 Indonesia 2Department of Metallurgy and Materials Engineering Universitas Indonesia Depok 16424 Indonesia

In this paper, we report the phase and crystallite size analysis of (Ti1-xMox)C-(Ni,Cr) with x = 0-0.5 cermet obtained by mechanical alloying of Ti, Mo, Ni, Cr and C elemental powders using a high-energy shaker ball mill under wet condition for 10 hours. The process used toluene as process control agent and the ball to mass ratio was 10:1. The mechanically milled powder was then consolidated and subsequently heated at a temperature 850°C for 2 hours under an argon flow to prevent oxidation. The product was characterized by X-ray diffraction (XRD) and scanning electron microscope equipped with energy dispersive analyzer. Results shown that, by the selection of appropriate condition during the mechanical alloying process, a metastable Ti-Ni-Cr-C powders could be obtained. The powder then allowed the in situ synthesis of TiC-(Ni,Cr) cermet which took place during exposure time at a high temperature that applied in reactive sintering step. Addition to molybdenum has caused shifting the TiC XRD peaks to a slightly higher angle which indicated that molybdenum dissolved in TiC phase. The crystallite size distribution of TiC is discussed in the report, which showing that the mean size decreased with the addition of molybdenum.

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Composite skyrmion bags in two-dimensional materials

arXiv

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arXiv 2018年

作者： Foster, David Kind, Charles Ackerman, Paul J. Tai, Jung-Shen b. Dennis, Mark R. Smalyukh, Ivan I. H. H. Wills Physics Laboratory University of Bristol BristolBS8 1TL United Kingdom School of Mathematics University of Bristol BristolBS8 1TW United Kingdom Department of Physics and Soft Materials Research Center University of Colorado BoulderCO80309 United States School of Physics and Astronomy University of Birmingham BirminghamB12 2TT United Kingdom Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado BoulderCO80309 United States

Skyrmions are particle-like topological excitations, studied in various condensed matter systems and models of high-energy physics (HEP). They occur as stable spin textures in certain planar magnetic materials [1-4] and as configurations in chiral nematic liquid crystals [5], having been originally proposed as model of atomic nuclei [10]. Since magnetic Skyrmions can be accelerated with a current [6-8], they have the potential to encode bits in low-power magnetic storage devices [9]. Drawing on techniques from HEP, we demonstrate that magnetic and liquid crystal Skyrmions interact like orientation dependent, localised particles, explaining previously observed Skyrmion behaviour. This interaction motivates the construction of Skyrmion bags: Textures of high topological degree which we realise experimentally in liquid crystals, and in magnetic materials by computer simulations. These Skyrmion bags configurations are nested multiple Skyrmions, which act like single Skyrmions in pairwise interaction, and under the inuence of a current in magnetic materials. These results emphasize equivalent Skyrmion behaviour in different physical systems, and suggest new, high-density magnetic memory storage devices based on Skyrmion bags. Copyright © 2018, The Authors. All rights reserved.

关键词： Magnetic storage

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Synthesis of green-emitting carbon quantum dots with excitation wavelength dependent photoluminescence obtained from aqueous beetroot extract

Synthesis of green-emitting carbon quantum dots with excitat...

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作者： Andrade, George R. S. Costa, Silvânio S. L. Nascimento, Cristiane C. Gimenez, Iara F. Postgraduate Program in Materials Science and Engineering Federal University of Sergipe Saõ Cristóvaõ Brazil Postgraduate Program in Chemistry Federal University of Bahia Salvador Brazil NUPEG Federal University of Sergipe Saõ Cristóvaõ Brazil Federal Institute of Education Science and Technology of Sergipe Aracaju Brazil Department of Chemistry Federal University of Sergipe Saõ Cristóvaõ Brazil

In this work, 3 simple, fast, labour and energy efficient methodologies were used to prepare carbon quantum dots (C-dots) using a red beetroot (beta vulgaris subsp. vulgaris var. vulgaris) aqueous extract as the carbon source: Alkali-assisted (AA), microwave-assisted (MA) and alkali-microwave-assisted (AMA) synthesis. TEM images shows nanoparticles with a nearly spherical morphology and diameters around 7.0 nm. FTIR spectra show characteristic peaks of C-H, C-O, O-H and C=C bonds for all the samples. The emission spectra show an interesting feature of the as-prepared samples: The emission band position can be tunable by changing the excitation wavelength. Comparing the 3 different methodologies in terms of photoluminescence properties, the one based only on the microwave-assisted heating has showed the most improved emission. © 2016 materials Research Society.

关键词： Semiconductor quantum dots

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Avoiding interpenetrations and fibre volume fraction corrections in representative unit cells for textile composites through advanced geometry generation 17

Avoiding interpenetrations and fibre volume fraction correct...

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17th European Conference on Composite materials, ECCM 2016

作者： Sevenois, R.D.b. Garoz, D. Gilabert, F.A. Van Paepegem, W. Department of Materials Science and Engineering Faculty of Engineering and Architecture Ghent University Technologiepark Zwijnaarde 903 ZwijnaardeB-9052 Belgium SIM vzw M3 Program Technologiepark-Zwijnaarde 935 GhentB-9052 Belgium

ISBN: (纸本)9783000533877

A novel method for the geometrical generation of Representative Unit Cells (RUC) of textile composites is proposed. The advanced technique retains the advantage of an analytical formulation from the current state-of-the-art but introduces variable asymmetric yarn cross sectional shapes and paths which can be tailored to the yarn shapes and cross sectional areas as measured from in-situ microscopy. In this way, interpenetrations and incorrect fibre volume fractions, which occur when using traditional RUC generation techniques [1, 2], are avoided. In addition, meshing becomes easier and no stiffness corrections are required. The new technique is validated through a comparison of the novel RUC to: 1) a RUC with constant cross section;and 2) a RUC constructed from direct in-situ micro computed X-ray tomographic measurements of a carbon-epoxy weave. The technique is also an excellent alternative for advanced unit cell generation techniques based on production process simulations, e.g.[3], in the case that the production process is unknown or an analytic periodic geometry is required. © 2016, European Conference on Composite materials, ECCM. All rights reserved.

关键词： Composite materials

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Unravelling competing microscopic interactions at a phase boundary: A single crystal study of the metastable antiferromagnetic pyrochlore Yb2Ge2O7

arXiv

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arXiv 2019年

作者： Sarkis, C.L. Rau, J.G. Sanjeewa, L.D. Powell, M. Kolis, J. Marbey, J. Hill, S. Rodriguez-Rivera, J.A. Nair, H.S. Gingras, M.J.P. Ross, K.A. Department of Physics Colorado State University 200 W. Lake St. Fort CollinsCO80523-1875 United States Max-Planck-Institut für Physik komplexer Systeme Dresden01187 Germany Department of Physics University of Windsor 401 Sunset Avenue WindsorONN9B 3P4 Canada Department of Chemistry Clemson University Hunter Chemistry Laboratory ClemsonSC29634 United States Department of Physics National High Magnetic Field Laboratory Florida State University 1800 East Paul Dirac Drive TallahasseeFL32310 United States NIST Center for Neutron Research National Institute of Standards and Technology GaithersburgMD20899 United States Materials Science and Engineering University of Maryland College ParkMD20742 United States Department of Physics University of Texas El Paso 500 W University Ave El PasoTX79902 United States Department of Physics and Astronomy University of Waterloo OntarioN2L 3G1 Canada Quantum Materials Program Canadian Institute for Advanced Research MaRS Centre West Tower 661 University Ave. TorontoONM5G 1M1 Canada

We report inelastic neutron scattering measurements from our newly synthesized single crystals of the structurally metastable antiferromagnetic pyrochlore Yb2Ge2O7. We determine the four symmetry-allowed nearest-neighbor anisotropic exchange parameters via fits to linear spin wave theory supplemented by fits of the high-temperature specific heat. The exchange parameters so-determined are strongly correlated to the values determined for the g-tensor components, as previously noted for the related Yb pyrochlore Yb2Ti2O7. To address this issue, we directly determined the g-tensor from electron paramagnetic resonance of 1% Yb-doped Lu2Ge2O7, thus enabling an unambiguous determination of the exchange parameters. Our results show that Yb2Ge2O7 resides extremely close to the classical phase boundary between an antiferromagnetic Γ5 phase and a splayed ferromagnet phase. by juxtaposing our results with recent ones on Yb2Ti2O7, our work illustrates that the Yb pyrochlore oxides represent ideal systems for studying quantum magnets in close proximity to classical phase boundaries. Copyright © 2019, The Authors. All rights reserved.

关键词： Antiferromagnetism

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New test set-up for measuring rate-dependent mode-I delamination properties of unidirectional and woven composites 17

New test set-up for measuring rate-dependent mode-I delamina...

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17th European Conference on Composite materials, ECCM 2016

作者： Spronk, S.W.F. Degrieck, J. Gilabert, F.A. Allaeys, F. Van Paepegem, W. Department of Materials Science and Engineering Faculty of Engineering and Architecture Ghent University Technologiepark-Zwijnaarde 903 ZwijnaardeB-9052 Belgium SIM vzw M3 Program Technologiepark-Zwijnaarde 935 GhentB-9052 Belgium

ISBN: (纸本)9783000533877

Impacts are highly dynamic events. Quasi-static test- and data reduction methods can thus not be used to characterize the response under impact, especially when the examined material is strain-rate sensitive. Delamination is a dominant failure mechanism in composite materials and the role played by the strain-rate in the material's integrity has to be studied under realistic load conditions. This work presents a new experimental setup designed to investigate the delamination process in mode-I when the specimen endures an impact load. A contactless optical technique is used to track the position and rotation of the specimen during the test. A finite element model is developed with the aim of correlating the features of the dynamic response with the value of fracture toughness. This experimental-numerical approach shows the importance of the inertia effects, which are clearly reflected on the speed of delamination. An adequate data reduction process is required to get a reliable value of the fracture toughness. © 2016, European Conference on Composite materials, ECCM. All rights reserved.

关键词： Delamination

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Identification of Antiferromagnetic Domains Via the Optical Magnetoelectric Effect

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Physical Review Letters 2018年第5期121卷 057601-057601页

作者： Vilmos Kocsis Karlo Penc Toomas Rõõm Urmas Nagel Jakub Vít Judit Romhányi Yusuke Tokunaga Yasujiro Taguchi Yoshinori Tokura István Kézsmárki Sándor bordács RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan Department of Physics Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group 1111 Budapest Hungary Institute for Solid State Physics and Optics Wigner Research Centre for Physics Hungarian Academy of Sciences H-1525 Budapest P.O.B. 49 Hungary National Institute of Chemical Physics and Biophysics 12618 Tallinn Estonia Institute of Physics ASCR Na Slovance 2 182 21 Prague 8 Czech Republic Faculty of Nuclear Science and Physical Engineering Czech Technical University Břehová 7 115 19 Prague 1 Czech Republic Okinawa Institute of Science and Technology Graduate University Onna-son Okinawa 904-0395 Japan Department of Advanced Materials Science University of Tokyo Kashiwa 277-8561 Japan Quantum-Phase Electronics Center Department of Applied Physics University of Tokyo Tokyo 113-8656 Japan Department of Applied Physics University of Tokyo Hongo Tokyo 113-8656 Japan Experimental Physics 5 Center for Electronic Correlations and Magnetism Institute of Physics University of Augsburg 86159 Augsburg Germany Hungarian Academy of Sciences Premium Postdoctor Program 1051 Budapest Hungary

The ultimate goal of multiferroic research is the development of a new-generation nonvolatile memory devices, where magnetic bits are controlled via electric fields with low energy consumption. Here, we demonstrate the optical identification of magnetoelectric (ME) antiferromagnetic (AFM) domains in the LiCoPO4 exploiting the strong absorption difference between the domains. This unusual contrast, also present in zero magnetic field, is attributed to the dynamic ME effect of the spin-wave excitations, as confirmed by our microscopic model, which also captures the characteristics of the observed static ME effect. The control and the optical readout of AFM/ME domains, demonstrated here, will likely promote the development of ME and spintronic devices based on AFM insulators.

关键词： Magnetoelectric effect Optical & microwave phenomena Multiferroics Single crystal materials Terahertz spectroscopy

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