RESUMO
BACKGROUND: Exposure to heat stress is a documented risk for Central American sugarcane harvesters. However, little is known about heat-related illness in this population. METHODS: This study examined the frequency of heat-related health effects among harvesters (n = 106) exposed to occupational heat stress compared to non-harvesters (n = 63). Chi-square test and gamma statistic were used to evaluate differences in self-reported symptoms and trends over heat exposure categories. RESULTS: Heat and dehydration symptoms (headache, tachycardia, muscle cramps, fever, nausea, difficulty breathing, dizziness, swelling of hands/feet, and dysuria) were experienced at least once per week significantly more frequently among harvesters. Percentages of workers reporting heat and dehydration symptoms increased in accordance with increasing heat exposure categories. CONCLUSIONS: A large percentage of harvesters are experiencing heat illness throughout the harvest demonstrating an urgent need for improved workplace practices, particularly in light of climate change and the epidemic of chronic kidney disease prevalent in this population.
Assuntos
Doenças dos Trabalhadores Agrícolas/etiologia , Fazendeiros , Transtornos de Estresse por Calor/etiologia , Temperatura Alta/efeitos adversos , Exposição Ocupacional/efeitos adversos , Adulto , Doenças dos Trabalhadores Agrícolas/epidemiologia , Clima , Transtornos de Estresse por Calor/epidemiologia , Humanos , Pessoa de Meia-Idade , Fatores de Risco , Saccharum , Local de Trabalho , Adulto JovemRESUMO
BACKGROUND: Occupational heat stress is a major concern in sugarcane production and has been hypothesized as a causal factor of a chronic kidney disease epidemic in Central America. This study described working conditions of sugarcane harvesters in Costa Rica and quantified their exposure to heat. METHODS: Non-participatory observation and Wet Bulb Globe Temperatures (WBGT) according to Spanish NTP (Technical Prevention Notes) guidelines were utilized to quantify the risk of heat stress. OSHA recommendations were used to identify corresponding exposure limit values. RESULTS: Sugarcane harvesters carried out labor-intensive work with a metabolic load of 261 W/m² (6.8 kcal/min), corresponding to a limit value of 26° WBGT which was reached by 7:30 am on most days. After 9:15 am, OSHA recommendations would require that workers only work 25% of each hour to avoid health risks from heat. CONCLUSIONS: Sugarcane harvesters are at risk for heat stress for the majority of the work shift. Immediate action is warranted to reduce such exposures.
Assuntos
Agricultura/estatística & dados numéricos , Transtornos de Estresse por Calor/etiologia , Temperatura Alta/efeitos adversos , Exposição Ocupacional/estatística & dados numéricos , Costa Rica , Humanos , Exposição Ocupacional/efeitos adversos , Fatores de TempoRESUMO
BACKGROUND AND AIMS: The mitochondrial control region (CR) was studied across five marsupialian orders, in order to give a detailed overview of its features. RESULTS: The CR is organised into three domains similar to the CR of placental mammals. However, the conservation of different features among the marsupial orders is in general more strict. In the first domain, two conserved blocks extended termination-associated sequences (ETAS 1 and ETAS 2) are present in all marsupial orders. In the third domain, the three conserved sequence blocks (CSB 1, CSB 2 and CSB 3) are present and complete, with CSB 1 being duplicated in four of five marsupial orders. CONCLUSIONS: The nucleotide frequency and secondary structures of the repeats were typical for marsupial species. The repeats are generally AT-rich except in Dasyuridae and Paucituberculata, which show a significant increase in GC content.
Assuntos
DNA Mitocondrial/química , Marsupiais/genética , Animais , Austrália , Sequência de Bases , Evolução Molecular , Variação Genética , Geografia , Dados de Sequência Molecular , Alinhamento de Sequência , América do SulRESUMO
Recent marsupials include about 280 species divided into 18 families and seven orders. Approximately 200 species live in Australia/New Guinea. The remaining species inhabit South America with some of these secondarily ranging into North America. In this study, we examine marsupial relationships and estimate their divergences times using complete mitochondrial (mt) genomes. The sampling, which includes nine new mtDNAs and a total number of 19 marsupial genomes, encompasses all extant orders and 14 families. The analysis identified a basal split between Didelphimorphia and remaining orders about 69 million years before present (MYBP), while other ordinal divergences were placed in Tertiary times. The monotypic South American order Microbiotheria (Dromiciops gliroides, Monito del Monte) was solidly nested among its Australian counterparts. The results suggest that marsupials colonized Australia twice from Antarctica/South America and that the divergence between Microbiotheria and its Australian relatives coincided with the geological separation of Antarctica and Australia. Within Australia itself, several of the deepest divergences were estimated to have taken place close to the Eocene/Oligocene transition.
Assuntos
Marsupiais/genética , Filogenia , Animais , DNA Mitocondrial/genética , Variação Genética , Marsupiais/classificação , Proteínas Mitocondriais/genética , América do Sul , Fatores de TempoRESUMO
The complete mitochondrial (mt) genomes of five marsupial species have been sequenced. The species represent all three South American orders (Didelphimorphia, Paucituberculata, and Microbiotheria). Phylogenetic analysis of this data set indicates that Didelphimorphia is a basal marsupial lineage followed by Paucituberculata. The South American microbiotherid Dromiciops gliroides (monito del monte) groups with Australian marsupials, suggesting a marsupial colonization of Australia on two occasions or, alternatively, a migration of an Australian marsupial lineage to South America. Molecular estimates suggest that the deepest marsupial divergences took place 64-62 million years before present (MYBP), implying that the radiation of recent marsupials took place after the K/T (Cretaceous/Tertiary) boundary. The South American marsupial lineages are all characterized by a putatively non-functional tRNA for lysine, a potential RNA editing of the tRNA for asparagine, and a rearrangement of tRNA genes at the origin of light strand replication.