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

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

Plant size and neighbourhood characteristics influence survival and growth in a restored ex‐agricultural ecosystem

Restoring woody vegetation on degraded agricultural land is a widespread and common ecological restoration practice. However, highly variable plant survival and growth limit outcomes for many projects. Inconsistent reporting and monitoring of projects mean that an assessment of the relative importance of community-assembly processes is limited, particularly over longer timescales. We use 7 years of monitoring data of nearly 2000 native trees and shrubs in a restoration project on ex-agricultural land in south-western Australia to test the potential effects of facilitation or competition from neighbouring plants, as well as look for patterns in their interaction with the attributes of individuals and species traits. Overall, plant size was the strongest single predictor of survival and incremental growth. Individual plants in neighbourhoods with higher inter-generic basal area were more likely to survive, with this effect strongest in smaller individuals. When plants were larger, they were less likely to grow when in neighbourhoods with high intra-generic basal area. Taller-growing plants (higher species maximum height) were more likely to survive when individuals were small (basal area of 1–10 cm2), compared with shorter growing plants. Growth was also more likely in taller-growing plants, and this relationship increased with the size of the individual. Recruitment was very low, with just 148 new recruits recorded across the 42 plots over 7 years. Maximizing the growth of plants in restorations in the early stages may promote survival and growth in the longer term. We also demonstrate that increased levels of inter-generic neighbouring plants may improve individual plant survival in the restoration of ex-agricultural land. As a result, we suggest tailoring direct-seeding methods to minimize clustering of congeneric individuals. We also highlight the need to find means of promoting recruitment for the long-term sustainability of restoration efforts

Getting value out of working memory through strategic prioritisation; implications for storage and control.

Working memory is an active system responsible for "the temporary maintenance and processing of information in the support of cognition and action" (Baddeley et al., 2021). In keeping with this, a growing body of research has explored the close links between working memory and attention, and how these might be harnessed to impact performance and possibly improve working memory efficiency. This is theoretically and practically important, given that working memory is a central hub in complex cognition yet is extremely capacity- and resource-limited. We review work carried out over the last ten years or so looking at how high 'value' items in working memory can be strategically prioritised through selective attention, drawing principally from visual working memory paradigms with young adult participants, while also discussing how the core effects extend to different task domains and populations. A consistent set of core findings emerges, with improved memory for items that are allocated higher 'value' but no change in overall task performance, and a recency advantage regardless of point allocation when items are encountered sequentially. Value-directed prioritisation is effortful, under top-down strategic control, and appears to vary with perceptual distraction and executive load. It is driven by processes operating during encoding, maintenance, and retrieval, though the extent to which these are influenced by different features of the task context remain to be mapped out. We discuss implications for working memory, attention, and strategic control, and note some possible future directions of travel for this promising line of research

Does value-based prioritization at working memory enhance long-term memory?

Research has demonstrated that individuals can direct their attention to valuable information in both working memory and long-term memory tasks with observable effects on performance. However, it is currently unclear whether prioritising an item for a working memory task automatically translates into a boost at long-term memory. This was examined in two experiments using relatively short (250 ms per item; Experiment 1) and longer (500 ms per item; Experiment 2) encoding times. Participants first completed a visual working memory task, in which they were presented with series of photographs of everyday objects. Following a brief delay (1,000 ms), they completed a four-alternative forced-choice test. Prior to encoding, participants were informed of the point values associated with each item. In some trials, the first item in the sequence was worth more points than the rest. In other trials, all items were equally valuable. After a filled delay, participants completed a surprise long-term memory task. At working memory, a value effect was reliably observed on recognition accuracy, along with some evidence of faster response times for high-value items. However, there was little consistent evidence of this effect automatically persisting into long-term memory. Thus, the benefits of attentional prioritization in working memory do not always translate into longer-term performance. More broadly, this provides further evidence that manipulations that enhance working memory performance do not necessarily enhance long-term memory

Effect of Interband Transitions on the c axis Penetration Depth of Layered Superconductors

The electromagnetic response of a system with two planes per unit cell involves, in addition to the usual intraband contribution, an added interband term. These transitions affect the temperature dependence and the magnitude of the zero temperature c-axis penetration depth. When the interplane hopping is sufficiently small, the interband transitions dominate the low temperature behaviour of the penetration depth which then does not reflect the linear temperature dependence of the intraband term and in comparison becomes quite flat even for a d-wave gap. It is in this regime that the pseudogap was found in our previous normal state calculations of the c-axis conductivity, and the effects are connected.Comment: 8 pages, 5 figure

On non-QRT Mappings of the Plane

We construct 9-parameter and 13-parameter dynamical systems of the plane which map bi-quadratic curves to other bi-quadratic curves and return to the original curve after two iterations. These generalize the QRT maps which map each such curve to itself. The new families of maps include those that were found as reductions of integrable lattices

Self-consistent solution of the Schwinger-Dyson equations for the nucleon and meson propagators

The Schwinger-Dyson equations for the nucleon and meson propagators are solved self-consistently in an approximation that goes beyond the Hartree-Fock approximation. The traditional approach consists in solving the nucleon Schwinger-Dyson equation with bare meson propagators and bare meson-nucleon vertices; the corrections to the meson propagators are calculated using the bare nucleon propagator and bare nucleon-meson vertices. It is known that such an approximation scheme produces the appearance of ghost poles in the propagators. In this paper the coupled system of Schwinger-Dyson equations for the nucleon and the meson propagators are solved self-consistently including vertex corrections. The interplay of self-consistency and vertex corrections on the ghosts problem is investigated. It is found that the self-consistency does not affect significantly the spectral properties of the propagators. In particular, it does not affect the appearance of the ghost poles in the propagators.Comment: REVTEX, 7 figures (available upon request), IFT-P.037/93, DOE/ER/40427-12-N9