Religious philanthropy and Chinese civil society

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Cadmium in cacao from Latin America and the Caribbean: A review of research and potential mitigation solutions

Cadmium is a heavy metal which accumulates in the body and affects our health. In order to control the amount we consume, the EU has set maximum permissible levels for different foods. A regulation specifying maximum levels of cadmium in cocoa and chocolate products came into force in January 2019 and similar regulations are being developed by other countries. In comparison to other cacao growing regions such as Africa and Asia-Pacific, some countries of Latin America and the Caribbean (LAC) are particularly impacted by worrying levels of cadmium in cacao beans that are a concern for the manufacturers of high-cacao content products. In this context, there is a pressing need to identify solutions that reduce cadmium levels in cacao beans and provide mitigation solutions at key processing stages in the value chain. This review presents the status of research on sources of cadmium contamination in soils, soil properties that affect cadmium bioavailability, physiological mechanisms and varietal differences in cadmium uptake by the cacao tree and the consequence of post-harvest processes. It presents potential mitigation solutions applicable to cacao that have been investigated through trials or considered by the research community. The review also includes information on ongoing research projects to gain a better understanding of the direction of research and potential gaps to be filled. This work was coordinated by Bioversity International and the Development Bank of Latin America (CAF) through the Latin American Cacao Initiative (ILAC). We thank all the institutions and individuals that provided information concerning research on cadmium and cacao and contributed to the review. We hope that this document is useful to understand the status of knowledge on this complex issue and guide future investments and collaboration to urgently provide solutions for stakeholders and particularly smallholder producers in LAC that are the most impacted. ✔ Spanish version available below: Related materia

Review of the CFC/ICCO/Bioversity project on cacao germplasm evaluation (1998-2010)

The CFC/ICCO/Bioversity project was in response to an urgent need to revitalize cacao breeding and research globally for increasing resistance to pests and disease. It aimed to strengthen national cacao improvement programmes and increase international collaboration by carrying out joint evaluation, selection and breeding activities in ten cocoa-producing countries. The project implemented in two phases – Phase I (1998- 2004) and Phase II (2004-2010), has been one of the most ambitious collaborative efforts in cacao breeding. With an understanding that a similar global collaboration is needed to tackle the impacts of climate change on cacao production, this review was developed in response to a request from the cocoa industry and research partners to evaluate the effectiveness of the project, identify key lessons learned for the implementation of new multisite evaluation field trials focused on increasing the resilience of cacao to the effects of climate change. The cacao research community will be able to use these lessons learned to be better prepared for, and more effective in, the execution of future collaborative research initiatives

Cadmio en el cacao de América Latina y el Caribe: Análisis de la investigación y soluciones potenciales para la mitigación

El cadmio es un metal pesado que se acumula en el cuerpo y afecta nuestra salud. Para controlar la cantidad que consumimos, la UE ha establecido los niveles máximos permitidos para diferentes alimentos. Un reglamento que especifica los niveles máximos de cadmio en los productos de cacao y chocolate entró en vigor en enero de 2019 y otros países están elaborando reglamentos similares. En comparación con otras regiones productoras de cacao como África y Asia-Pacífico, algunos países de América Latina y el Caribe (ALC) se ven particularmente afectados por los preocupantes niveles de cadmio en los granos de cacao que son una preocupación para los fabricantes de productos con alto contenido de cacao. En este contexto, existe una necesidad apremiante de identificar soluciones que reduzcan los niveles de cadmio en los granos de cacao y brinden soluciones de mitigación en etapas clave de procesamiento en la cadena de valor. Esta análisis presenta el estado de la investigación sobre las fuentes de contaminación de cadmio en los suelos, las propiedades del suelo que afectan la biodisponibilidad del cadmio, los mecanismos fisiológicos y las diferencias de variedades en la absorción de cadmio por parte del árbol de cacao y las consecuencias de los procesos posteriores a la cosecha. La análisis presenta posibles soluciones de mitigación aplicables al cacao que han sido investigadas a través de ensayos o consideradas por la comunidad de investigación. La análisis también incluye información sobre proyectos de investigación en curso para obtener una mejor comprensión de la dirección de la investigación y las posibles lagunas que deben cubrirse. Este trabajo fue coordinado por Bioversity International y el Banco de Desarrollo de América Latina (CAF) a través de la Iniciativa Latinoamericana de Cacao (ILAC). Agradecemos a todas las instituciones y personas que proporcionaron información sobre la investigación sobre cadmio y cacao y contribuyeron a la análisis. Esperamos que este documento sea útil para comprender el estado del conocimiento sobre este tema complejo y guiar las inversiones futuras y la colaboración para brindar soluciones urgentes a las partes interesadas y en particular a los pequeños productores en ALC que son los más afectados. ✔ Versión en inglés disponible a continuación: Related materia

Long-Baseline Interferometric Multiplicity Survey of the Sco-Cen OB Association

We present the first multiplicity-dedicated long baseline optical interferometric survey of the Scorpius-Centaurus-Lupus-Crux association. We used the Sydney University Stellar Interferometer to undertake a survey for new companions to 58 Sco-Cen B- type stars and have detected 24 companions at separations ranging from 7-130mas, 14 of which are new detections. Furthermore, we use a Bayesian analysis and all available information in the literature to determine the multiplicity distribution of the 58 stars in our sample, showing that the companion frequency is F = 1.35 and the mass ratio distribution is best described as a power law with exponent equal to -0.46, agreeing with previous Sco-Cen high mass work and differing significantly from lower-mass stars in Tau-Aur. Based on our analysis, we estimate that among young B-type stars in moving groups, up to 23% are apparently single stars. This has strong implications for the understanding of high-mass star formation, which requires angular momentum dispersal through some mechanism such as formation of multiple systems.Comment: 7 figures, 5 tables, accepted for publication in MNRA

Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements

The thermal conductivity k of the iron-arsenide superconductor LiFeAs (Tc ~ 18K) was measured in single crystals at temperatures down to T~50mK and in magnetic fields up to H=17T, very close to the upper critical field Hc2~18T. For both directions of the heat current, parallel and perpendicular to the tetragonal c-axis, a negligible residual linear term k/T is found as T ->0, revealing that there are no zero-energy quasiparticles in the superconducting state. The increase in k with magnetic field is the same for both current directions and it follows closely the dependence expected for an isotropic superconducting gap. There is no evidence of multi-band character, whereby the gap would be different on different Fermi-surface sheets. These findings show that the superconducting gap in LiFeAs is isotropic in 3D, without nodes or deep minima anywhere on the Fermi surface. Comparison with other iron-pnictide superconductors suggests that a nodeless isotropic gap is a common feature at optimal doping (maximal Tc).Comment: 4 pages, 3 figure

Fermi-surface transformation across the pseudogap critical point of the cuprate superconductor La1.6−x_{1.6-x}Nd0.4_{0.4}Srx_{x}CuO4_4

The electrical resistivity $\rho$ and Hall coefficient R$_H$ of the tetragonal single-layer cuprate Nd-LSCO were measured in magnetic fields up to $H = 37.5$ T, large enough to access the normal state at $T \to 0$, for closely spaced dopings $p$ across the pseudogap critical point at $p^\star = 0.235$. Below $p^\star$, both coefficients exhibit an upturn at low temperature, which gets more pronounced with decreasing $p$. Taken together, these upturns show that the normal-state carrier density $n$ at $T = 0$ drops upon entering the pseudogap phase. Quantitatively, it goes from $n = 1 + p$ at $p = 0.24$ to $n = p$ at $p = 0.20$. By contrast, the mobility does not change appreciably, as revealed by the magneto-resistance. The transition has a width in doping and some internal structure, whereby R$_H$ responds more slowly than $\rho$ to the opening of the pseudogap. We attribute this difference to a Fermi surface that supports both hole-like and electron-like carriers in the interval $0.2 < p < p^\star$, with compensating contributions to R$_H$. Our data are in excellent agreement with recent high-field data on YBCO and LSCO. The quantitative consistency across three different cuprates shows that a drop in carrier density from $1 + p$ to $p$ is a universal signature of the pseudogap transition at $T=0$. We discuss the implication of these findings for the nature of the pseudogap phase.Comment: 11 pages, 12 figure

International Space Station Common Cabin Air Assembly Condensing Heat Exchanger Hydrophilic Coating Operation, Recovery, and Lessons Learned

The ability to control the temperature and humidity of an environment or habitat is critical for human survival. These factors are important to maintaining human health and comfort, as well as maintaining mechanical and electrical equipment in good working order to support the human and to accomplish mission objectives. The temperature and humidity of the International Space Station (ISS) United States On-orbit Segment (USOS) cabin air is controlled by the Common Cabin Air Assembly (CCAA). The CCAA consists of a fan, a condensing heat exchanger (CHX), an air/water separator, temperature and liquid sensors, and electrical controlling hardware and software. The CHX is the primary component responsible for control of temperature and humidity. The CCAA CHX contains a chemical coating that was developed to be hydrophilic and thus attract water from the humid influent air. This attraction forms the basis for water removal and therefore cabin humidity control. However, there have been several instances of CHX coatings becoming hydrophobic and repelling water. When this behavior is observed in an operational CHX in the ISS segments, the unit s ability to remove moisture from the air is compromised and the result is liquid water carryover into downstream ducting and systems. This water carryover can have detrimental effects on the ISS cabin atmosphere quality and on the health of downstream hardware. If the water carryover is severe and widespread, this behavior can result in an inability to maintain humidity levels in the USOS. This paper will describe the operation of the five CCAAs within the USOS, the potential causes of the hydrophobic condition, and the impacts of the resulting water carryover to downstream systems. It will describe the history of this behavior and the actual observed impacts to the ISS USOS. Information on mitigation steps to protect the health of future CHX hydrophilic coatings as well as remediation and recovery of the full heat exchanger will be discussed

Evidence for a small hole pocket in the Fermi surface of underdoped YBa2Cu3Oy

The Fermi surface of a metal is the fundamental basis from which its properties can be understood. In underdoped cuprate superconductors, the Fermi surface undergoes a reconstruction that produces a small electron pocket, but whether there is another, as yet undetected portion to the Fermi surface is unknown. Establishing the complete topology of the Fermi surface is key to identifying the mechanism responsible for its reconstruction. Here we report the discovery of a second Fermi pocket in underdoped YBa2Cu3Oy, detected as a small quantum oscillation frequency in the thermoelectric response and in the c-axis resistance. The field-angle dependence of the frequency demonstrates that it is a distinct Fermi surface and the normal-state thermopower requires it to be a hole pocket. A Fermi surface consisting of one electron pocket and two hole pockets with the measured areas and masses is consistent with a Fermi-surface reconstruction caused by the charge-density-wave order observed in YBa2Cu3Oy, provided other parts of the reconstructed Fermi surface are removed by a separate mechanism, possibly the pseudogap.Comment: 23 pages, 5 figure

Chemical potential oscillations from a single nodal pocket in the underdoped high-Tc superconductor YBa2Cu3O6+x

The mystery of the normal state in the underdoped cuprates has deepened with the use of newer and complementary experimental probes. While photoemission studies have revealed solely `Fermi arcs' centered on nodal points in the Brillouin zone at which holes aggregate upon doping, more recent quantum oscillation experiments have been interpreted in terms of an ambipolar Fermi surface, that includes sections containing electron carriers located at the antinodal region. To address the question of whether an ambipolar Fermi surface truly exists, here we utilize measurements of the second harmonic quantum oscillations, which reveal that the amplitude of these oscillations arises mainly from oscillations in the chemical potential, providing crucial information on the nature of the Fermi surface in underdoped YBa2Cu3O6+x. In particular, the detailed relationship between the second harmonic amplitude and the fundamental amplitude of the quantum oscillations leads us to the conclusion that there exists only a single underlying quasi-two dimensional Fermi surface pocket giving rise to the multiple frequency components observed via the effects of warping, bilayer splitting and magnetic breakdown. A range of studies suggest that the pocket is most likely associated with states near the nodal region of the Brillouin zone of underdoped YBa2Cu3O6+x at high magnetic fields.Comment: 7 pages, 4 figure