Agricultural intensification in the tropics is one way to meet rising global food demand in coming decades(1,2). Although this strategy can potentially spare land from conversion to agriculture(3), it relies on large material inputs. Here we quantify one such material cost, the phosphorus fertilizer required to intensify global crop production atop phosphorus-fixing soils and achieve yields similar to productive temperate agriculture. Phosphorus-fixing soils occur mainly in the tropics, and render added phosphorus less available to crops(4,5). We estimate that intensification of the 8-12% of global croplands overlying phosphorus-fixing soils in 2005 would require 1-4 Tg P yr(-1) to overcome phosphorus fixation, equivalent to 8-25% of global inorganic phosphorus fertilizer consumption that year. This imposed phosphorus 'tax' is in addition to phosphorus added to soils and subsequently harvested in crops, and doubles (2-7 Tg P yr(-1)) for scenarios of cropland extent in 2050(6). Our estimates are informed by local-, state- and national-scale investigations in Brazil, where, more than any other tropical country, low-yielding agriculture has been replaced by intensive production. In the 11 major Brazilian agricultural states, the surplus of added inorganic fertilizer phosphorus retained by soils post harvest is strongly correlated with the fraction of cropland overlying phosphorus-fixing soils (r(2) = 0.84, p < 0.001). Our interviews with 49 farmers in the Brazilian state of Mato Grosso, which produces 8% of the world's soybeans mostly on phosphorus-fixing soils, suggest this phosphorus surplus is required even after three decades of high phosphorus inputs. Our findings in Brazil highlight the need for better understanding of long-term soil phosphorus fixation elsewhere in the tropics. Strategies beyond liming, which is currently widespread in Brazil, are needed to reduce phosphorus retention by phosphorus-fixing soils to better manage the Earth's finite phosphate rock supplies and move towards more sustainable agricultural production.

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Invasive cervical cancer disproportionately affects women without sufficient access to care, with higher rates among minority groups in higher-income countries and women in low-resource regions of the world. Many elements contribute to racial/ethnic disparities in the cervical cancer continuum - from screening and diagnosis to treatment and outcome. Sociodemographic factors, access to healthcare, income and education level, and disease stage at diagnosis are closely linked to such inequities. Despite the identification of such elements, racial/ethnic disparities persist, and are widening in several minority subgroups, particularly in older women, who are ineligible for human papillomavirus (HPV) vaccination and are underscreened. Recent studies suggest that racial/ethnic differences in HPV infection exist and may also have a role in observed differences in cervical cancer. In this review, we provide an overview of the current literature on racial disparities in cervical cancer screening, incidence, treatment and outcome to inform future strategies to reduce persistent inequities.

The aim of this study was to evaluate the performance of the Centers for Dental Specialties (CDS) in the country and associations with sociodemographic indicators of the municipalities, structural variables of services and primary health care organization in the years 2004-2009. The study used secondary data from procedures performed in the CDS to the specialties of periodontics, endodontics, surgery and primary care. Bivariate analysis by χ2 test was used to test the association between the dependent variable (performance of the CDS) with the independents. Then, Poisson regression analysis was performed. With regard to the overall achievement of targets, it was observed that the majority of CDS (69.25%) performance was considered poor/regular. The independent factors associated with poor/regular performance of CDS were: municipalities belonging to the Northeast, South and Southeast regions, with lower Human Development Index (HDI), lower population density, and reduced time to deployment. HDI and population density are important for the performance of the CDS in Brazil. Similarly, the peculiarities related to less populated areas as well as regional location and time of service implementation CDS should be taken into account in the planning of these services.

Objective: To evaluate the association of breastfeeding duration, pacifier use and nasal air flow with occlusal disorders among children. Methods: This cross-sectional observational study included 138 children aged 4 and 5 years selected in all the daycare centers of the city of Campo Limpo Paulista, Brazil. Questionnaires were applied to mothers to identify total duration of exclusive breastfeeding and non-nutritive sucking. The independent variables were: Sucking (pacifier, bottle, finger), breastfeeding duration and nasal air flow. The dependent variables were: Open bite, crossbite, overjet, overbite, diastema and maxillary deficiency. Frequency distribution calculations were performed, a chi-square test, the Fisher exact test and, after that, stepwise logistic regression were used for statistical analysis, and the level of significance was set at 5%. Results: The use of a pacifier was the most deleterious factor and increased chances of having open bite in 33.3 times, marked overjet in 2.77 times and posterior crossbite in 5.26 times. Conclusion: There was a significant association between non-nutritive sucking, particularly the use of a pacifier, and occlusal disorders. These findings are important to plan the treatment of preschoolers.Keywords: Breastfeeding. Malocclusion. Primary dentition. Objetivo: avaliar a associação do tempo de amamentação natural, tempo de uso de chupeta e aeração nasal em relação a problemas oclusais em crianças. Métodos: foi realizado um estudo observacional transversal com universo de 138 crianças entre 4 e 5 anos, de creches de Campo Limpo Paulista/SP. Foram aplicados questionários às mães com o intuito de identificar o tempo de amamentação natural total e exclusiva e hábitos deletérios. Utilizaram-se as variáveis independentes hábitos deletérios (chupeta, mamadeira e dedo), tempo de amamentação natural e aeração nasal; e as variáveis dependentes mordida aberta, mordida cruzada, overjet, sobremordida, presença de diastema e atresia. Foram realizados cálculos das distribuições das frequências, teste de associação do qui-quadrado, exato de Fisher e, em seguida, regressão logística pelo método de stepwise, utilizando nível de significância de 5%. Resultados: o uso de chupeta foi considerado o mais prejudicial dos hábitos deletérios, aumentando em 33,3 vezes a chance de mordida aberta; 2,77 vezes a chance de apresentar overjet acentuado e 5,26 vezes as chances de apresentar mordida cruzada posterior. Conclusão: houve uma forte associação entre hábitos deletérios (especialmente o tempo de uso de chupeta) e problemas oclusais, sendo esse fato importante no planejamento do tratamento de pacientes pré-escolares.Palavras-chave: Aleitamento materno. Má oclusão. Hábitos. Dentição decídua.