"Pandemics know no borders," but Responses to Pandemics Do: Global Health, COVID-19, and Latin America.

This article focuses on Brazil and Peru, the Latin American epicenter of the coronavirus pandemic during 2020 and 2021. The pandemic magnified the legacy of years of neoliberal policies, corruption and racism in these countries, the limitations of their poverty-reduction programs, the fragility of their democratic systems, and the insufficient political regard for public health and basic sanitation. I rely on the concepts of negligence and necropolitics. The first refers to the abdication of authorities in providing sufficient basic services to its citizens. The second - coined by Achille Mbembe before the pandemic - is used to explain the banalization by governments of preventable deaths of discriminated social groups. On a global level, the problematic access to medical equipment and vaccines was a failure because of the hoarding of vaccines by rich nations and the blaming of developing countries for their high mortality. The result was that national and international governmental reactions to COVID-19 worsened health asymmetries within countries and between the Global North and South.

Determining usefulness of machine learning in materials discovery using simulated research landscapes.

When existing experimental data are combined with machine learning (ML) to predict the performance of new materials, the data acquisition bias determines ML usefulness and the prediction accuracy. In this context, the following two conditions are highly common: (i) constructing new unbiased data sets is too expensive and the global knowledge effectively does not change by performing a limited number of novel measurements; (ii) the performance of the material depends on a limited number of physical parameters, much smaller than the range of variables that can be changed, albeit such parameters are unknown or not measurable. To determine the usefulness of ML under these conditions, we introduce the concept of simulated research landscapes, which describe how datasets of arbitrary complexity evolve over time. Simulated research landscapes allow us to use different discovery strategies to compare standard materials exploration with ML-guided explorations, i.e. we can measure quantitatively the benefit of using a specific ML model. We show that there is a window of opportunity to obtain a significant benefit from ML-guided strategies. The adoption of ML can take place too soon (not enough information to find patterns) or too late (dense datasets only allow for negligible ML benefit), and the adoption of ML can even slow down the discovery process in some cases. We offer a qualitative guide on when ML can accelerate the discovery of new best-performing materials in a field under specific conditions. The answer in each case depends on factors like data dimensionality, corrugation and data collection strategy. We consider how these factors may affect the ML prediction capabilities and discuss some general trends.

Prominent out-of-plane diffraction in helium scattering from a methyl-terminated Si(111) surface.

Due to their electrochemical and oxidative stability, organic-terminated semiconductor surfaces are well suited to applications in, for example, photoelectrodes and electrochemical cells, which explains the lively interest in their detailed characterization. Helium atom scattering (HAS) is a useful tool to carry out such characterization. Here, we have simulated HAS in He/CH3-Si(111) based on density functional theory (DFT) potential energy surfaces (PESs) and multi-configuration time-dependent Hartree (MCTDH) dynamics. Our analysis of HAS shows that most diffraction taking place in this system corresponds to high-order out-of-plane peaks. This is a general trend that does not depend on the specific features of the simulations, such as the inclusion or not of the van der Waals long-range effects. This is the first and only He-surface system for which such huge out-of-plane diffraction has been described. This striking theoretical finding should encourage new experimental developments to confirm this previously unreported effect.

Overcoming social segregation in health care in Latin America.

Latin America continues to segregate different social groups into separate health-system segments, including two separate public sector blocks: a well resourced social security for salaried workers and their families and a Ministry of Health serving poor and vulnerable people with low standards of quality and needing a frequently impoverishing payment at point of service. This segregation shows Latin America's longstanding economic and social inequality, cemented by an economic framework that predicted that economic growth would lead to rapid formalisation of the economy. Today, the institutional setup that organises the social segregation in health care is perceived, despite improved life expectancy and other advances, as a barrier to fulfilling the right to health, embodied in the legislation of many Latin American countries. This Series paper outlines four phases in the history of Latin American countries that explain the roots of segmentation in health care and describe three paths taken by countries seeking to overcome it: unification of the funds used to finance both social security and Ministry of Health services (one public payer); free choice of provider or insurer; and expansion of services to poor people and the non-salaried population by making explicit the health-care benefits to which all citizens are entitled.

At the Roots of The World Health Organization's Challenges: Politics and Regionalization.

The World Health Organization's (WHO's) leadership challenges can be traced to its first decades of existence. Central to its governance and practice is regionalization: the division of its member countries into regions, each representing 1 geographical or cultural area. The particular composition of each region has varied over time-reflecting political divisions and especially decolonization. Currently, the 194 member countries belong to 6 regions: the Americas (35 countries), Europe (53 countries), the Eastern Mediterranean (21 countries), South-East Asia (11 countries), the Western Pacific (27 countries), and Africa (47 countries). The regions have considerable autonomy with their own leadership, budget, and priorities. This regional organization has been controversial since its beginnings in the first days of WHO, when representatives of the European countries believed that each country should have a direct relationship with the headquarters in Geneva, Switzerland, whereas others (especially the United States) argued in favor of the regionalization plan. Over time, regional directors have inevitably challenged the WHO directors-general over their degree of autonomy, responsibilities and duties, budgets, and national composition; similar tensions have occurred within regions. This article traces the historical roots of these challenges.

Experimental and theoretical study of rotationally inelastic diffraction of H2(D2) from methyl-terminated Si(111).

Fundamental details concerning the interaction between H2 and CH3-Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H2 and D2 from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H2 compared to the strong RID features observed for D2 over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuation of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH3-Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H2 and D2 have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H2 (D2) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H2(D2)/CH3-Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H2 with a hybrid organic-semiconductor interface, which can be used to further investigate energy flow in technologically relevant systems.

An Asymmetrical Network: National and International Dimensions of the Development of Mexican Physiology.

This article examines the history of Mexican physiology during the period 1910-60 when two noted investigators, José J. Izquierdo, first, and Arturo Rosenblueth, second, inscribed their work into an international network of medical research. The network had at its center the laboratory of Walter B. Cannon at Harvard University. The Rockefeller Foundation was its main supporter. Rosenblueth was quite familiar with the network because he worked with Cannon at Harvard for over ten years before returning to Mexico in the early 1940s. Izquierdo and Rosenblueth developed different strategies to face adverse conditions such as insufficient laboratory equipment, inadequate library resources, a small scientific community, and ephemeral political support. Both acquired local influence and international prestige, but the sources of financial and academic power remained in the United States. This case study provides insight into the circulation of scientific ideas and practices in an important Latin American country and suggests that the world's circulation of science among industrial and developing nations during the mid-twentieth century was intrinsically asymmetric but opened temporary opportunities for talented individuals and groups of researchers.

A public health achievement under adversity: the eradication of poliomyelitis from Peru, 1991.

The fight to achieve global eradication of poliomyelitis continues. Although native transmission of poliovirus was halted in the Western Hemisphere by the early 1990s, and only a few cases have been imported in the past few years, much of Latin America's story remains to be told. Peru conducted a successful flexible, or flattened, vertical campaign in 1991. The initial disease-oriented programs began to collaborate with community-oriented primary health care systems, thus strengthening public-private partnerships and enabling the common goal of poliomyelitis eradication to prevail despite rampant terrorism, economic instability, and political turmoil. Committed leaders in Peru's Ministry of Health, the Pan American Health Organization, and Rotary International, as well as dedicated health workers who acted with missionary zeal, facilitated acquisition of adequate technologies, coordinated work at the local level, and increased community engagement, despite sometimes being unable to institutionalize public health improvements.

'Eradication was a dirty word': Anti-gambiae campaign, between cooperation and rivalry (1938-1940).

This article analyzes the efforts of the International Health Division of the Rockefeller Foundation (IHDRF) in its project initiative that resulted in the extermination of the African mosquito Anopheles gambiae from Brazil in 1940. This species, which originated in Dakar, Senegal, was identified in the Brazilian city of Natal in 1930, where insufficient local emergency sanitation actions enabled it to spread into the interior of the Brazilian northeast, causing an unprecedented malaria epidemic in the Americas in 1938, after years of silent spread. We will analyse the formation of Brazil's Malaria Service of the Northeast (MSNE), discussing its political and scientific controversies and how the transition from the idea of extermination to the idea of eradication was consolidated in the political process of creating this successful sanitation campaign. In addition, we will discuss how the integration and transnational development of medical entomology at the time was a fundamental factor in the cooperation and challenges among scientists involved in this campaign. The international cooperation of scientists, albeit oriented towards the project of eradication of this mosquito, organised different research agendas and gained new insights into the global dissemination of mosquito-borne diseases.

Covid-19 as an issue of memory, truth, and justice: an interview with Deisy Ventura. / Covid-19 como tema de memória, verdade e justiça: entrevista com Deisy Ventura.

This interview with Deisy Ventura, professor at the Faculty of Public Health of the Universidade de São Paulo, discusses the political dimension of the covid-19 pandemic in Brazil. She has become a leading reference on the subject due to her extensive knowledge of international law, with a focus on health. In this interview, Deisy Ventura offers some reflections on global health and discusses the handling of the pandemic in Brazil and its human rights implications. According to Ventura, the Brazilian government had a systematic policy for the spread of the virus, and the pandemic should be treated as a matter of memory, truth, and justice.

Entrevista com Deisy Ventura, professora titular da Faculdade de Saúde Pública da Universidade de São Paulo, que discute a dimensão política da pandemia de covid-19 no Brasil. A pesquisadora se tornou uma das principais referências no assunto por seu amplo conhecimento de direito internacional com foco em saúde. Na entrevista, ela apresenta reflexões relacionadas à saúde global, além de discutir a gestão da pandemia no país e suas implicações para os direitos humanos. De acordo com a pesquisadora, houve no Brasil uma política governamental sistemática de disseminação do vírus, e a pandemia deveria ser tratada como uma questão de memória, verdade e justiça.

Backlash in global health and the end of AIDS' exceptionalism in Brazil, 2007-2019.

This paper examines the decline of the AIDS Programme in Brazil, the Latin American country most affected by the epidemic, with emphasis in the second decade of the twenty-first century. For many years, Brazil served as a model in Global Health due to a comprehensive preventive policy, a partnership between the government and health activists and the support of life-saving drugs as public goods rather than commodities. The regression of AIDS policies in Brazil interacted with developments in the United States as well as with multilateral agencies like UNAIDS that emphasised biomedicalisation in the response to the disease where broad human-rights programmes and alliance with activists were not priorities. International programmes like the 'Ending AIDS' campaign indirectly undermined the exceptional status AIDS enjoyed since the late 1980s. The backlash in Brazilian policies to fight AIDS was a result of the fragmentation of the left and the empowerment of radical conservative authoritarian and religious forces. The result was the breakdown of the long-held belief that successful anti-AIDS disease programmes could simultaneously help control the disease and build better healthcare systems and ultimately prompted the end of the special place AIDS' policy had in Brazil.

Limitations of machine learning models when predicting compounds with completely new chemistries: possible improvements applied to the discovery of new non-fullerene acceptors.

We try to determine if machine learning (ML) methods, applied to the discovery of new materials on the basis of existing data sets, have the power to predict completely new classes of compounds (extrapolating) or perform well only when interpolating between known materials. We introduce the leave-one-group-out cross-validation, in which the ML model is trained to explicitly perform extrapolations of unseen chemical families. This approach can be used across materials science and chemistry problems to improve the added value of ML predictions, instead of using extrapolative ML models that were trained with a regular cross-validation. We consider as a case study the problem of the discovery of non-fullerene acceptors because novel classes of acceptors are naturally classified into distinct chemical families. We show that conventional ML methods are not useful in practice when attempting to predict the efficiency of a completely novel class of materials. The approach proposed in this work increases the accuracy of the predictions to enable at least the categorization of materials with a performance above and below the median value.

Data-Driven Analysis of Hole-Transporting Materials for Perovskite Solar Cells Performance.

We have created a dataset of 269 perovskite solar cells, containing information about their perovskite family, cell architecture, and multiple hole-transporting materials features, including fingerprints, additives, and structural and electronic features. We propose a predictive machine learning model that is trained on these data and can be used to screen possible candidate hole-transporting materials. Our approach allows us to predict the performance of perovskite solar cells with reasonable accuracy and is able to successfully identify most of the top-performing and lowest-performing hole-transporting materials in the dataset. We discuss the effect of data biases on the distribution of perovskite families/architectures on the model's accuracy and offer an analysis with a subset of the data to accurately study the effect of the hole-transporting material on the solar cell performance. Finally, we discuss some chemical fragments, like arylamine and aryloxy groups, which present a relatively large positive correlation with the efficiency of the cell, whereas other groups, like thiophene groups, display a negative correlation with power conversion efficiency (PCE).

High-throughput virtual screening for organic electronics: a comparative study of alternative strategies.

We present a review of the field of high-throughput virtual screening for organic electronics materials focusing on the sequence of methodological choices that determine each virtual screening protocol. These choices are present in all high-throughput virtual screenings and addressing them systematically will lead to optimised workflows and improve their applicability. We consider the range of properties that can be computed and illustrate how their accuracy can be determined depending on the quality and size of the experimental datasets. The approaches to generate candidates for virtual screening are also extremely varied and their relative strengths and weaknesses are discussed. The analysis of high-throughput virtual screening is almost never limited to the identification of top candidates and often new patterns and structure-property relations are the most interesting findings of such searches. The review reveals a very dynamic field constantly adapting to match an evolving landscape of applications, methodologies and datasets.

Performance of van der Waals DFT approaches for helium diffraction on metal surfaces.

The ability of the different approaches proposed to date to include the effects of van der Waals (vdW) dispersion forces in density functional theory (DFT) is currently under debate. Here, we used the diffraction of He on a Ru(0 0 0 1) surface as a challenging benchmark system to analyze the suitability of several representative approaches, from the ones correcting the exchange-correlation generalized gradient approximation (GGA) functional, to the ones correcting the DFT energies through pairwise-based methods. To perform our analysis, we have built seven continuous potential energy surfaces (PESs) and carried out quantum dynamics simulations using a multi-configuration time-dependent Hartree method. Our analysis reveals that standard DFT within the PBE-GGA framework, although it overestimates diffraction probabilities, yields the best results in comparison with available experimental measurements. On the other hand, although several of the existing vdW DFT approaches yield physisorption wells in very good agreement with experiment, they all seem to overestimate the long-distance corrugation of the PES, the region probed by He scattering, resulting in a large overestimation of diffraction probabilities.

[Pathways, science, and the State in Peru, 1850-1930]. / Caminos, ciencia y Estado en el Perú, 1850-1930.

This study offers a panoramic view of the relation between the development of naturalist studies and the control of territory in Peru from the mid-nineteenth century through the first decades of the twentieth. Notable scientific development took place during this period, in terms of research and of academic institutions. Both research and academe enjoyed the support of the State, which had greater resources within its reach following the period of relative instability subsequent to Independence in 1821. Although this process of development was fragmented and discontinuous, it resulted in the first mapmaking work and geographic and naturalist studies, as well as the creation of communication pathways. Further, it was justified by its potential contribution to an export economy and to the cultural prestige of civilian elites.

International health, the early cold war and Latin America.

This article offers a panoramic vision of the development of international health in Latin America during the late 1940s and the 1950s, when a series of bilateral and multilateral institutions, such as the World Health Organization and UNICEF, were founded and reshaped. The language, policies, and activities of these new institutional actors were heavily influenced by the context of the early Cold War between the era's superpowers: the United States and the Soviet Union. Vertical campaigns against yaws and malaria--implemented under the leadership of Fred L. Soper, director of the Pan American Sanitary Bureau--symbolized international health's technical orientation, as well as its contribution to the modernization of the countries of the region. The Cold War period has received little attention by historians of medicine, though it bears certain similarities to historiographical discussions of the relationship between tropical medicine and imperialism in the early 20th century.