Abstract There is a growing concern about the participation of wild hosts and reservoirs in the epidemiology of several pathogens, particularly within the context of environmental changes and the expansion of the One Health concept. The aim of this study was to investigate the presence of hemoplasmas in opossums rescued from the metropolitan region of Rio de Janeiro state, Brazil. Blood samples were collected from 15 Didelphis aurita and subjected to DNA extraction and PCR using primers for the 16S rRNA and 23S rRNA genes. Physical examination and hematological analysis were also performed. Three out of 15 opossums tested positive for hemotropic Mycoplasma spp. by PCR and showed hematological alterations such as anemia and leukocytosis. Clinical signs were non-specific and associated to traumatic lesions. The phylogenetic analysis indicated that the hemoplasma detected was positioned between 'Ca. Mycoplasma haemodidelphis' detected in D. virginiana from North American and hemoplasmas recently detected in D. aurita from the state of Minas Gerais, Brazil. This study indicates the existence of hemoplasma infections in D. aurita from the metropolitan region of Rio de Janeiro, and reinforce the need for new epidemiological inquiries to clarify the participation of these in the dynamics of circulation of tick-borne pathogens.

Resumo Há uma crescente preocupação com a participação de hospedeiros e reservatórios silvestres na epidemiologia de diversos patógenos, principalmente no contexto das mudanças ambientais e da expansão do conceito "One Health". O objetivo deste estudo foi investigar a presença de hemoplasmas em gambás resgatados da região metropolitana do estado do Rio de Janeiro, Brasil. Amostras de sangue foram coletadas de 15 Didelphis aurita e submetidas à extração de DNA e PCR utilizando-se "primers" para os genes 16S rRNA e 23S rRNA. O exame físico e a análise hematológica também foram realizados. Três dos 15 gambás testaram positivo para Mycoplasma spp. hemotrópico por PCR. Os sinais clínicos eram inespecíficos e associados a lesões traumáticas. Anemia e leucocitose foram detectadas em animais positivos. A análise filogenética indicou que o hemoplasma detectado estava posicionado entre 'Ca. Mycoplasma haemodidelphis' detectado em D. virginiana da América do Norte e hemoplasmas recentemente detectados em D. aurita do estado de Minas Gerais, Brasil. Este estudo indica a existência de infecções por hemoplasmas em D. aurita, da região metropolitana do Rio de Janeiro, e reforça a necessidade de novos inquéritos epidemiológicos, para esclarecer a participação destes na dinâmica de circulação de patógenos transmitidos por carrapatos.

ABSTRACT The membrane bioreactor process has been consolidated in recent years as an alternative to traditional methods for the treatment of effluents from the paper production industry. Recently, the introduction of support material in these reactors has contributed to the improvement of their performance, in view of the greater biological activity that occurs as a result of the development of biofilms. Thus, the presence of adhered biomass gives the membrane bioreactor an additional capacity to withstand shock loads, as well as contributing to the biodegradation of potentially toxic and recalcitrant compounds such as lignin derivatives. Thus, the present work aimed to evaluate the performance of a sequencing batch moving bed membrane bioreactor and applied to the treatment of real low-load effluent from paper production. The reactor was evaluated for its performance in removing soluble chemical oxygen demand, total phenol, true color, aromatic (UV254mn) and lignin (UV280mn) compounds. At the same time, the reactor was evaluated in terms of the membrane clogging process, by monitoring the transmembrane pressure, the concentration of extracellular polymeric substances and soluble microbial products. Under the conditions tested, the sequencing batch moving bed membrane bioreactor achieved an average removal efficiency of 89; 39; 38; 57; and 73% for CODs, UV254nm, UV280nm, true color and total phenols, respectively. Regarding membrane clogging, the variables UV254nm, UV280nm and total phenols were directly correlated with the increase in transmembrane pressure (TMP).

RESUMO O processo de biorreator com membranas tem se consolidado nos últimos anos como uma alternativa aos métodos tradicionais para o tratamento de efluentes da indústria de produção de papel. Recentemente, a introdução de material suporte nesses reatores tem contribuído para a melhoria de seu desempenho, tendo em vista a maior atividade biológica que se verifica em decorrência do desenvolvimento de biofilme. Assim, a presença da biomassa aderida confere uma capacidade adicional ao biorreator com membranas em suportar choques de cargas, bem como pode contribuir para a biodegradação de compostos potencialmente tóxicos e recalcitrantes como derivados da lignina. Desse modo, o presente trabalho teve como objetivo avaliar o desempenho de um biorreator à membrana de leito móvel operado em batelada sequencial e aplicado ao tratamento de efluente real de baixa carga oriundo da produção de papel. O reator foi avaliado quanto ao seu desempenho na remoção de demanda química de oxigênio solúvel, fenol total, cor verdadeira, compostos aromáticos (UV254nm) e lignínicos (UV280nm). Paralelamente, o reator foi avaliado quanto ao processo de colmatação das membranas, por meio do monitoramento da pressão transmembrana, da concentração de substâncias poliméricas extracelulares e produtos microbianos solúveis). Nas condições testadas, o biorreator à membrana de leito móvel operado em batelada sequencial atingiu eficiência média de remoção de 89% para demanda química de oxigênio solúvel, 39% para UV254nm, 38% para UV280nm, 57% para cor verdadeira e 73% para fenóis totais. Em relação à colmatação das membranas, as variáveis UV254nm, UV280nm e fenóis totais correlacionaram-se diretamente com o aumento da pressão transmembrana (PTM).

In this work, mixtures of ceramic powders containing Al2O3 with different amounts of Y2O3 (1%, 3%, 5% and 10wt.%) along their cross-section were fabricated to obtain multilayer composites based on Al2O3 with different levels of Y3Al5O12 (YAG) as reinforcement. Monolithic cylindrical multilayer Al2O3 blocks were compacted and subsequentially, sintered at 1610°C for 4h. Phase stability, microstructural aspects, and physical and mechanical properties of the specimens were acquired by relative density, X-ray diffraction, scanning electron microscopy, Vickers hardness, fracture toughness, Young’s modulus and biaxial flexural strength measurements. The results indicated that monolithic alumina specimens exhibited relative density of 98%, with average hardness of 1203 ±83 HV, fracture toughness of 2.1 ±0.8 MPa.m1/2 and flexural strength of 187 ±64 MPa. Progressive incorporation of Y2O3 into the chemical composition of the specimens led to formation of the YAG phase by solid state reaction during sintering, which reduced hardness and increased densification, fracture toughness and flexural strength, with average values of HV=1023 ±28 HV, KIC=3.5 ±0.3 MPa.m1/2, σf=273 ±58 MPa and 14% Y3Al5O12 for the specimens with 10wt.% Y2O3. This improvement is probably associated with toughness mechanisms, such as crack deflection and residual thermal stresses between the phases present in the composites.

Resumen El objetivo de este estudio es analizar empíricamente las actitudes de los migrantes latinoamericanos radicados en Estados Unidos hacia la migración de retorno, y las actitudes hacia la emigración permanente de sus descendientes nacidos en la Unión Americana. A través de un análisis cuantitativo utilizando datos provenientes de una encuesta nacional realizada en territorio estadounidense, demostramos que la identidad “americana/estadounidense”, la identidad “latina”, los confines del “americanismo” y las experiencias con la discriminación étnica-racial determinan la disposición de los latinos en Estados Unidos a emigrar y relocalizarse en su país de origen o ascendencia. Para los mexicoamericanos o “chicanos”, los factores de mayor impacto en su disposición a emigrar son el apego a la identidad “americana” y la creencia de que para ser americano uno tiene que ser de tez blanca. Mientras, los migrantes no mexicanos son más propensos a contemplar la emigración si han sido discriminados en Estados Unidos.

Abstract The aim of this study is to empirically analyze the attitudes of Latin American migrants living in the United States about return migration and the attitudes of their U.S.-born descendants about permanent emigration. The authors perform a quantitative analysis using data from a U.S. national survey to demonstrate that the “American/U.S. American,” the “Latino” identity, the confines of Americanism, and the experiences with ethnic-racial discrimination determine the willingness of U.S. Latinos to emigrate or relocate in their country of origin or descent. For Mexican-Americans or Chicanos, the most important factors in their willingness to emigrate are their adherence to the “American” identity and the belief that to be American, they would have to have white skin. Meanwhile, non-Mexican migrants are more likely to consider emigration if they have been discriminated against in the United States.

ABSTRACT Malaria is the most dangerous disease caused by the Plasmodium parasite, which occurs in different endemic and non-endemic areas of the world, where it can cause different clinical complications that can end in death. Due to the number of people affected by malaria in different countries, vaccination is considered the only way to prevent infection by reducing the number of people dying and eliminating malaria from different areas despite the development of resistance to drug treatments antiparasitics that have been used to control the disease. A variety of vaccines have been under development in recent years, but many of them have achieved more successful results than others and some of them have been discontinued in research due to poor results and possible side effects. In the present investigation, it was proposed to carry out a review on the subject, and also to propose an educational intervention strategy that allows the population to be made aware of the importance of vaccination and the prevention of this disease in the communities. Experts were consulted for the educational proposal, for information processing the Saaty AHP multi-criteria decision method was used too.

RESUMEN La malaria es la enfermedad más peligrosa causada por el parásito Plasmodium, que se presenta en diferentes áreas endémicas y no endémicas del mundo, donde puede causar diferentes complicaciones clínicas que pueden terminar en la muerte. Debido a la cantidad de personas afectadas por la malaria en diferentes países, la vacunación se considera la única forma de prevenir la infección reduciendo el número de personas que mueren y eliminando la malaria de diferentes zonas a pesar del desarrollo de resistencia a los tratamientos con medicamentos antiparasitarios que se han utilizado para controlar la enfermedad. Se ha estado desarrollando durante los últimos años una variedad de vacunas, pero muchas de ellas han logrado resultados más exitosos que otras y algunas de ellas han sido descontinuadas en investigación debido a sus bajos resultados y posibles efectos secundarios. En la presente investigación se propuso realizar una revisión respecto al tema, y además proponer una estrategia de intervención educativa que permita sencibilizar a la población respecto a la importancia de la vacunación y la prevención de esta enfermedad en las comunidades. Se realizó una consulta a expertos para la propuesta educativa, para el procesamiento de la información se empleó el método de decisión multicreiterio AHP de Saaty.

Abstract Submesoscale eddies (1-10 km diameter) were identified using surface velocity observations obtained from a high-frequency radar system (HFR) operated in Todos Santos Bay (TSB), Baja California, Mexico. Eddies were detected through a special case of the Okubo-Weiss parameter for divergent flows in the form of eigenvalues of the Jacobian matrix. The detection method, applied for a surface velocity grid, shows encouraging results in the recognition and tracking of submesoscale features in TSB. The detection method is rapid and efficient. Results show the formation and persistence of an eddy structure inside the Bay in December 6, 2010, displaying a trajectory from NE to SW until disappearing at the center of the Bay. The eddy is approximately 4 km in diameter with a frequency of ~0.1f (f is the Coriolis parameter). The real part of the Okubo-Weiss parameter ranged between − 4 × 10 − 9 to − 1 × 10 − 9 s − 2, and outlined the eddy for approximately 9 hours. Although it is difficult to identify the origin of the detected submesoscale eddy, its appearance coincided with a drop in relative atmospheric humidity suggesting land-ocean Santa Ana winds as a possible generating mechanism.

ABSTRACT The influence of easterly and northeasterly dry and warm Santa Ana winds (SAw) on the surface circulation of Todos Santos Bay, Mexico, is studied from surface currents and wind data measured during the most extreme periods of activity (autumn-winter season). Sea surface currents were measured using a system of coastally-based HF radar stations between 2009 and 2015. Winter-mean surface circulation showed a cyclonic tendency. Atmospheric variables allowed the grouping of ~122 SAw events, 23% of which caused a noticeable change in the background circulation. Event-mean current patterns showed dissimilar responses to the acting winds, with some SAw events driving weak offshore currents, another that developed an eddy-pair circulation inside the bay, and one rather intense (winds of 8-10 m s-1) that developed a clockwise circulation overturning the cyclonic long-term winter-mean. In general, changes in the circulation were related to an offshore transport of surface waters into the open ocean.

RESUMEN Se utilizan datos de vientos y corrientes superficiales para estudiar la influencia de vientos de Santa Ana (SAw), relativamente secos y cálidos del este y noreste, sobre la circulación superficial de la Bahía de Todos Santos, México. El análisis se realiza para periodos de vientos intensos en la época de otoño-invierno. Las corrientes superficiales fueron medidas entre 2009 y 2015 usando un sistema de estaciones de radar HF sobre la costa. La circulación superficial promedio durante el invierno mostró una tendencia ciclónica. Las variables atmosféricas permitieron identificar ~122 eventos SAw, de los cuales 23% causó un cambio notable en la circulación media. Los patrones de circulación promedio durante los eventos cálidos mostraron respuestas diferentes a los vientos forzantes. En algunos eventos la influencia de los vientos generó corrientes débiles hacia afuera de la costa, mientras que en otros se desarrolló una circulación de dos remolinos ciclónicos dentro de la bahía. Un evento intenso (8-10 ms-1) desarrolló una circulación anticiclónica, opuesta a la circulación ciclónica promedio de invierno. En general, los cambios en la circulación mostraron relación con un transporte en la misma dirección del viento hacia el océano abierto.

Abstract The objective of this study was to evaluate the input of suspended sediment from the slope toe in the São Francisco River channel, in Northeast Brazil, under different soil bioengineering techniques. Sediments were collected in the years of 2013, 2014 and 2015, in five transects crossing the river channel. Sediment input in the sampling points was higher in the year of 2013, i.e., the year of the highest river discharge. Sediment supply to the river channel for a period of 3 years (2013, 2014 and 2015), was evaluated at 20, 40 and 60% depth, along five different transects (P1= riverbank, P2= beginning of the thalweg, P3= middle of the thalweg, P4= end of the thalweg, and P5 = margin of the side sandybar), oriented by the presence or absence of erosion control techniques (treatments) such as: 1-Natural Vegetated Slope; 2-Vegetated Riprap; 3-Eroded Slope; 4-Live Cribwall and 5-Vetiver grass Contour Line. Sediments input was different in all evaluated transects, and the one identified as Eroded Slope at 20% depth presented the lowest amount of suspended sediment load. There was a decrease in the total amount of suspended sediment in the evaluated periods, probably due to the progressive decrease in the river discharge, and the protection provided by the soil bioengineering techniques.

Resumen Este estudio evalúa la entrada de sedimentos en suspensión de la punta de la pendiente del cauce del río São Francisco, en el noreste de Brasil, bajo diferentes técnicas de bioingeniería de suelos. Los sedimentos se recolectaron en 2013, 2014 y 2015, en cinco transectos que cruzan el cauce del río. La entrada de sedimentos en los puntos de muestreo fue mayor en el año 2013, es decir, el año de la mayor descarga del río. El suministro de sedimentos al cauce del río por un período de 3 años (2013, 2014 y 2015), fue evaluado a 20, 40 y 60% de profundidad, a lo largo de cinco transectos diferentes (P1 = ribera, P2 = inicio del thalweg, P3 = medio del thalweg, P4 = final del thalweg, y P5 = margen de la barra arenosa lateral), orientados por la presencia o ausencia de técnicas de control de erosión (tratamientos) tales como: 1-Talud Vegetado Natural; Riprap de 2 vegetaciones; Pendiente 3-erosionada; 4-Live Cribwall y 5-Vetiver grass Contour Line. La entrada de sedimentos fue diferente en todos los transectos evaluados, y el identificado como Pendiente Erosionada al 20% de profundidad presentó la menor cantidad de carga de sedimentos en suspensión. Hubo una disminución en la cantidad total de sedimentos en suspensión en los períodos evaluados, probablemente debido a la disminución progresiva del caudal del río y la protección que brindan las técnicas de bioingeniería de suelos.

Abstract Introduction: breast cancer (BC) is the most common cancer in women and its relationship with dietary factors particularly dairy products, has been investigated trough several studies but up to now there are still not enough results to confirm the association between breast cancer and dairy products. Objective: the purpose of this systematic review was to expand the number of systematic reviews that to date exist on the relationship between dairy products consumption and risk of breast cancer. A comprehensive search of the PubMed, Scopus and Embase was performed from September 2005 to September 2018 in which one case control and cohorts’ studies were included. Results: eighteen studies were finally selected for the review (10 case-control and 8 cohorts’ studies). These studies reported several statistically significant associations (OR, HR, RR) between dairy product consumption and the risk of breast cancer. Seven case-control and four cohorts’ studies showed that dairy product consumption was inversely associated with the risk of breast cancer, on the other hand, a positive association was found in two case-control and non- significant association was found between dairy product consumption and the risk of breast cancer in the remaining studies (one case-control and four cohorts’ studies) Conclusion: although an inverse association was observed in most studies, it’s difficult to draw conclusions when the methodology methods to collect the dairy product intake and the servings or portions measurements were different in each study. On the other hand, not all studies used the same confounding variable to estimate risk.

Resumen Introducción: el cáncer de mama (BC) es de los cánceres más comunes en mujeres, y su relación con los factores dietéticos y, en particular, con los productos lácteos, ha sido investigada a través de varios estudios, pero hasta ahora no hay resultados suficientes que confirmen la asociación entre cáncer de mama y productos lácteos. Objetivo: el objetivo de esta revisión fue ampliar y actualizar el número de revisiones sistemáticas que hasta día de hoy existen sobre la relación entre el consumo de productos lácteos y el cáncer de mama. Metodología: se realizó una búsqueda exhaustiva en las bases de datos PubMed, Scopus y Embase entre septiembre de 2005 y septiembre de 2018 en la que se incluyeron estudios de casos y controles y estudios de cohortes. Resultados: se seleccionaron 18 estudios (10 estudios de casos-controles y 8 estudios de cohorte). Siete casos-controles y cuatro estudios de cohorte mostraron que el consumo de productos lácteos tenía una asociación inversa con el riesgo de cáncer de mama y, por otro lado, en dos estudios de casos-controles se observó una asociación positiva. No se encontró una asociación significativa entre el consumo de productos lácteos y el cáncer de mama en los restantes estudios (1 caso-control y 4 cohortes). Conclusión: aunque se observó una asociación inversa en la mayoría de los estudios, es difícil sacar conclusiones cuando los métodos metodológicos para recolectar la ingesta de lácteos y las porciones o las mediciones de las porciones fueron diferentes en cada estudio. Por otro lado, no todos los estudios tienen en cuenta las mismas variables de confusión.

Abstract: Ketamine is an inductor of dissociative anesthesia used for more than 50 years, its use has been variable through the years in our country. Beyond its anesthetic properties, this drug is also use for acute and chronic pain alongside with refractory depression, making its use trendy again. This paper review the present indications in the acute pain field regarding patient selection, doses, adverse events and the safety precautions under an acute pain service scheme (full version visit http://www.painoutmexico.com).

Resumen: La ketamina es un inductor de anestesia disociativa conocida desde hace más de 50 años, y cuyo uso ha sido fluctuante en nuestro país. Más allá de sus propiedades anestésicas, su uso como fármaco para el manejo del dolor agudo, crónico y la depresión, le han conferido un nuevo auge; sin embargo, las dosis y el manejo en pacientes con dolor agudo difiere con las guías y las publicaciones establecidas. Este artículo pretende hacer una revisión de las indicaciones establecidas, las dosis recomendadas, así como el manejo de los efectos adversos dentro del marco de un Servicio de Dolor Agudo con respecto al uso de ketamina en el contexto de dolor agudo (para ver el artículo completo visite http://www.painoutmexico.com).

Abstract After the Spanish Civil War, poor hygiene and nutritional deficiencies among a large part of Spain’s population contributed to the rise of epidemic diseases. Exanthematic typhus posed a challenge to the health authorities, especially during the spring of 1941, when the epidemiological cycle of the disease and the lack of infrastructures combined to create a serious health crisis. The Franco regime, aware that this situation posed a threat to its legitimacy, promptly used social exclusion as part of its health policy against the epidemic. This article provides an in-depth analysis of the case of Valencia, a city that was behind Republican lines during the war, and therefore received successive waves of refugees as Franco’s troops advanced.

Resumen Tras la Guerra Civil, las deficientes condiciones higiénico-dietéticas de gran parte de la población española favorecieron la aparición de enfermedades epidémicas. El tifus exantemático puso en jaque a las autoridades sanitarias, especialmente durante la primavera de 1941, cuando el ciclo epidemiológico de la enfermedad y la falta de infraestructuras se aliaron para provocar una grave crisis sanitaria. El régimen franquista, consciente de que esta situación dificultaba su legitimación, no dudó en utilizar la exclusión social como parte de su política sanitaria contra esta epidemia. El artículo analiza en profundidad el caso de Valencia, una ciudad que durante la guerra, por hallarse en la retaguardia republicana, había acogido sucesivas oleadas de refugiados a medida que avanzaban las tropas franquistas.

Resumo A Agricultura concentra maior risco de acidentes ocupacionais, entretanto sua dimensão é desconhecida pela escassez de estudos brasileiros e subnotificação na área rural. O objetivo deste artigo é avaliar a prevalência e os fatores associados aos acidentes de trabalho em fumicultores em São Lourenço Sul-RS. Estudo transversal com amostra representativa de 488 fumicultores, avaliando características sociodemográficas, comportamentais, atividades laborais e associação com acidentes de trabalho na vida. Prevalência de acidentes na vida foi de 24%, encontrada associação positiva com sexo masculino (RP1,62IC-95%1,04-2,52), ser arrendatário (RP1,87IC-95%1,29-2,72), realização manocas (RP2,00IC-95%1,14-3,52) e problemas psiquiátricos menores (RP 1,58 IC-95%1,06-2,35). Dentre os acidentes graves, 46% foram superficiais e 26%, fraturas. Necessário implementar políticas preventivas de acidentes laborais na área rural e, em particular, na fumicultura brasileira; avançar na busca da compreensão dos aspectos relacionados ao processo de trabalho impactantes ao risco de acidentes.

Abstract Agriculture has the highest risk of accidents. In Brazil the reality of this situation is unknown owing to scarcity of studies and underreporting of workplace accidents in rural areas. This article aims to evaluate workplace accident prevalence and associated factors among tobacco farm in Sao Lourenco do Sul-RS, Brazil. Cross-sectional study with 488 tobacco farmers, assessing sociodemographic, behavioural, labour characteristics and association with workplace accidents occurring in their lifetime. The injury prevalence was 24%. Being male (PR 1.62; 95%CI 1.04-2.52), and tenant farmer (PR 1.87; 95%CI 1.29-2.72), bundling tobacco leaves (PR 2.00; 95%CI 1.14-3.52) and having minor psychiatric disorders (PR 1.58; 95%CI 1.06-2.35) were positively associated with accidents. 46% of serious injuries caused superficial lesions and 26% caused fractures. Rural workplace accident prevention policies need to be established, particularly for tobacco farming. Larger studies are needed to understand work process-related aspects that increase the risk of accidents.

Resumo A Agricultura concentra maior risco de acidentes ocupacionais, entretanto sua dimensão é desconhecida pela escassez de estudos brasileiros e subnotificação na área rural. O objetivo deste artigo é avaliar a prevalência e os fatores associados aos acidentes de trabalho em fumicultores em São Lourenço Sul-RS. Estudo transversal com amostra representativa de 488 fumicultores, avaliando características sociodemográficas, comportamentais, atividades laborais e associação com acidentes de trabalho na vida. Prevalência de acidentes na vida foi de 24%, encontrada associação positiva com sexo masculino (RP1,62IC-95%1,04-2,52), ser arrendatário (RP1,87IC-95%1,29-2,72), realização manocas (RP2,00IC-95%1,14-3,52) e problemas psiquiátricos menores (RP 1,58 IC-95%1,06-2,35). Dentre os acidentes graves, 46% foram superficiais e 26%, fraturas. Necessário implementar políticas preventivas de acidentes laborais na área rural e, em particular, na fumicultura brasileira; avançar na busca da compreensão dos aspectos relacionados ao processo de trabalho impactantes ao risco de acidentes.

Abstract Agriculture has the highest risk of accidents. In Brazil the reality of this situation is unknown owing to scarcity of studies and underreporting of workplace accidents in rural areas. This article aims to evaluate workplace accident prevalence and associated factors among tobacco farm in Sao Lourenco do Sul-RS, Brazil. Cross-sectional study with 488 tobacco farmers, assessing sociodemographic, behavioural, labour characteristics and association with workplace accidents occurring in their lifetime. The injury prevalence was 24%. Being male (PR 1.62; 95%CI 1.04-2.52), and tenant farmer (PR 1.87; 95%CI 1.29-2.72), bundling tobacco leaves (PR 2.00; 95%CI 1.14-3.52) and having minor psychiatric disorders (PR 1.58; 95%CI 1.06-2.35) were positively associated with accidents. 46% of serious injuries caused superficial lesions and 26% caused fractures. Rural workplace accident prevention policies need to be established, particularly for tobacco farming. Larger studies are needed to understand work process-related aspects that increase the risk of accidents.

Abstract: Background and Aims: Tropical forests play an indispensable role to confront and reduce environmental degradation. The objective of this work was to determine, through ecological niche simulation models, the historical and current distribution of Cedrela odorata in Mexico. Methods: A base of 1747 presence data of C. odorata was used. For the modeling 19 climatic-environmental variables were used, as well as the layers of altitude, orientation, slope and soil type. The ecological niche modeling was carried out in the program MaxEnt, with 75% of the sample for training and the Logistic, Cumulative, Raw and Cloglog models. The validation was carried out with 25% of the sample and the Crossvalidate technique. Key results: The use of the Cloglog regression is the one that most adheres to the potential distribution for the species, otherwise using the Raw type modeling, since the projection of the potential area is very restrictive and compact, followed by the Cumulative regression and the Logistic regression, being these an intermediate point for the modeling of the historical distribution of C. odorata in Mexico. Conclusions: The historical distribution obtained from this model showed that the species has very high values of probability in the southern part of the Yucatán Península, north and south of Chiapas and the coastal plain of the Gulf in the Veracruz state with respect to the current distribution reported. This suggests a reduction in the distribution of the species in the country.

Resumen: Antecedentes y Objetivos: Los bosques tropicales juegan un papel indispensable para enfrentar y reducir la degradación ambiental. El objetivo de este trabajo fue determinar, mediante modelos de simulación de nicho ecológico, la distribución histórica y actual de Cedrela odorata en México. Métodos: Se empleó una base de 1747 datos de presencia de C. odorata. Para la modelación se emplearon 19 variables climato-ambientales y las capas de altitud, orientación, pendiente y tipo de suelos. La modelación de nicho ecológico se realizó en el programa MaxEnt con 75% de la muestra para el entrenamiento y los modelos Logistic, Cumulative, Raw y Cloglog. La validación se realizó con 25% de la muestra y la técnica Crossvalidate. Resultados clave: El empleo de la regresión Cloglog es la que más se apega a la distribución potencial para la especie, caso contrario al emplear la modelación de tipo Raw, ya que la proyección del área potencial es muy restrictiva y compacta, seguido de la regresión Cumulative y la regresión Logistic, siendo estas un punto intermedio para la modelación de la distribución histórica de C. odorata en México. Conclusiones: La distribución histórica obtenida a partir de este modelo mostró que la especie tiene una alta probabilidad de distribuirse en la parte sur de la Península de Yucatán, norte y sur de Chiapas, y la llanura costera del Golfo en el estado de Veracruz con respecto al área actual reportada. Esto sugiere una reducción del nicho ecológico de la especie en el país.