Partially linear models on Riemannian manifolds

In partially linear models the dependence of the response y on (x^T,t) is modeled through the relationship y=\x^T \beta+g(t)+\epsilon where \epsilon is independent of (x^T,t). In this paper, estimators of \beta and g are constructed when the explanatory variables t take values on a Riemannian manifold. Our proposal combine the flexibility of these models with the complex structure of a set of explanatory variables. We prove that the resulting estimator of \beta is asymptotically normal under the suitable conditions. Through a simulation study, we explored the performance of the estimators. Finally, we applied the studied model to an example based on real dataset.Comment: 7 pages, 2 figure

A Note on the Estimation of the Hölder Constant

In this article, we develop a nonparametric estimator for the Hölder constant of a density function. We consider a simulation study to evaluate the performance of the proposal and construct smooth bootstrap confidence intervals. Also, we give a brief review over the impossibility to decide whether a density function is Hölder.Fil: Henry, Guillermo Sebastian. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodriguez, Daniela Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sued, Raquel Mariela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Innovation in the Fight Against Infectious Diseases

The discovery of antibiotics in 1928 led the world to believe that the fight against infectious diseases was one to be won within a few years. Nowadays, nearly 90 years following the discovery of penicillin, infectious diseases remain one of the main causes of mortality worldwide, with lower respiratory tract infections, diarrhoeal diseases, and tuberculosis ranking among the top 10 causes of death according to the World Health Organization (WHO). In recent years, the advent of antibiotic resistance, the anti-vaccination movement, and humanitarian crises have seen a rise in infectious diseases that were once thought to be nearly eradicated, such as polio, tuberculosis and measles

‘Maybe we can turn the tide’ : an explanatory mixed-methods study to understand how knowledge brokers mobilise health evidence in low- and middle-income countries

Background: Little is known about how knowledge brokers (KBs) operate in low- and middle-income countries (LMICs) to translate evidence for health policy and practice. These intermediaries facilitate relationships between evidence producers and users to address public health issues. Aims and objectives: To increase understanding, a mixed-methods study collected data from KBs who had acted on evidence from the 2015 Global Maternal Newborn Health Conference in Mexico. Methods: Of the 1000 in-person participants, 252 plus 72 online participants (n=324) from 56 countries completed an online survey, and 20 participants from 15 countries were interviewed. Thematic analysis and application of knowledge translation (KT) theory explored factors influencing KB actions leading to evidence uptake. Descriptive statistics of respondent characteristics were used for cross-case comparison. Findings: Results suggest factors supporting the KB role in evidence uptake, which include active relationships with evidence users through embedded KB roles, targeted and tailored evidence communication to fit the context, user receptiveness to evidence from a similar country setting, adaptability in the KB role, and action orientation of KBs. Discussion and conclusions: Initiatives to increase evidence uptake in LMICs should work to establish supportive structures for embedded KT, identify processes for ongoing cross-country learning, and strengthen KBs already showing effectiveness in their roles

Hydrometallurgical extraction of Al and Si from kaolinitic clays

Herein is presented the results of a study on the hydrometallurgic extractionand recovery of aluminum and silicon by leaching of kaolinitic clays with HF. Thestudied extraction parameters were: temperature, reaction time, solid/liquid ratio,concentration, and precipitating agent mass. In the leaching process, mineraldissolutions near 100% were obtained when working at 348 K, solid/liquid ratio2% w/v, HF 12% v/v, for 120 minutes. The HF leach liquor generated from thedissolution of kaolinitic clays contains H2SiF6 and H3AlF6. Studies were conductedto recover the two valuable fluorides as K2SiF6 and Na3AlF6 by precipitation withalkaline salts from the leach liquor. Phases of precipitated fluorides were identifiedby XRD and surface morphology by SEM. The purity of the K2SiF6 precipitate was98.8%, whereas for Na3AlF6, it was 89.3%. Also, both synthesized solids are ofhigh commercial value due to their industrial applications.Fil: Pinna, Eliana Guadalupe. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Suarez, Daniela Silvana. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Rosales, Gustavo Daniel. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Rodriguez, Mario Humberto. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin

Robust estimators in partly linear regression models on Riemannian manifolds

Under a partly linear model we study a family of robust estimates for the regression parameter and the regression function when some of the predictors take values on a Riemannian manifold. We obtain the consistency and the asymptotic normality of the proposed estimators. Simulations and an application to a real dataset show the good performance of our proposal under small samples and contamination.Fil: Henry, Guillermo Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas "Luis A. Santalo". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Matemáticas "Luis A. Santalo"; ArgentinaFil: Rodriguez, Daniela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas "Luis A. Santalo". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Matemáticas "Luis A. Santalo"; Argentin

Applying the Theoretical Domains Framework to understand knowledge broker decisions in selecting evidence for knowledge translation in low- and middle-income countries

Background: Health-related organisations disseminate an abundance of clinical and implementation evidence that has potential to improve health outcomes in low- and middle-income countries (LMICs), but little is known about what influences a user decision to select particular evidence for action. Knowledge brokers (KBs) play a part as intermediaries supporting evidence-informed health policy and practice by selecting and synthesising evidence for research users, and therefore understanding the basis for KB decisions, can help inform knowledge translation strategies. The Theoretical Domains Framework (TDF), a synthesis of psychological theories, was selected as a promising analysis approach because of its widespread use in identifying influences on decisions to act on evidence-based healthcare guidelines. This study explored its application in the context of KB decisions regarding evidence for use in LMICs. Methods: The study analysed data collected from participants of a 2015 global maternal and newborn health conference in Mexico. A total of 324 conference participants from 56 countries completed an online survey and 20 from 15 countries were interviewed about evidence use and sharing after the conference. TDF domains and constructs were retrospectively applied and adapted during coding of qualitative data to enhance understanding of the KB decision process in selecting evidence for action. Results: Application of the TDF involved challenges related to overlapping constructs, retrospective use, and complexities of global health settings and relevant knowledge. Codes needed to be added or adapted to account for how KBs' internal reflections on external factors influenced their actions in selecting evidence to share and use, and the decisions they made during the process. Four themes of the rationale for changing the TDF were identified during analysis, namely Influences from Beyond the Organisation, Knowledge Selection as a Process, Access and Packaging of Knowledge, and Fit for Use. Conclusions: Theories of individual behaviour, such as those in the TDF, can enhance understanding of the decisions made by actors such as KBs along dissemination and knowledge translation pathways. Understanding how KBs reflect on evidence and interact with their environment has the potential for improving global dissemination efforts and LMIC-to-LMIC exchange of implementation evidence