Geostatistics as a tool to study mite dispersion in physic nut plantations.

Spatial distribution studies in pest management identify the locations where pest attacks on crops are most severe, enabling us to understand and predict the movement of such pests. Studies on the spatial distribution of two mite species, however, are rather scarce. The mites Polyphagotarsonemus latus and Tetranychus bastosi are the major pests affecting physic nut plantations (Jatropha curcas). Therefore, the objective of this study was to measure the spatial distributions of P. latus and T. bastosi in the physic nut plantations. Mite densities were monitored over 2 years in two different plantations. Sample locations were georeferenced. The experimental data were analyzed using geostatistical analyses. The total mite density was found to be higher when only one species was present (T. bastosi). When both the mite species were found in the same plantation, their peak densities occurred at different times. These mites, however, exhibited uniform spatial distribution when found at extreme densities (low or high). However, the mites showed an aggregated distribution in intermediate densities. Mite spatial distribution models were isotropic. Mite colonization commenced at the periphery of the areas under study, whereas the high-density patches extended until they reached 30 m in diameter. This has not been reported for J. curcas plants before.

Efficiency and economic feasibility of pest control systems in watermelon cropping.

The aim of this work was to determine the efficiency and feasibility of two different watermelon pest control systems on pest infestations, natural enemies, and on the productivity and sustainability of watermelon cropping. Two independent experiments were carried out during the dry season of 2011. Both experiments were carried out using a randomized block experimental design, with three treatments; weekly application of pesticide (WAP), integrated pest management (IPM), and nonpesticide application (control); and four replicates. Arthropods sampling was performed every 2 d by direct counting at five randomly selected points in each plot. Samples were taken by beating the leaves from the apical portion of the plant against a white plastic tray. Arthropods that moved along the soil surface were sampled weekly using pitfall traps. Both WAP and IPM treatments negatively affected the arthropod population. We conclude that IPM is an attractive strategy for watermelon cropping both economically and environmentally because it provides the grower with an option to lower production cost, achieves the same production, and there is less need for pesticide application when compared with the prophylactic control treatment when pesticides are applied on a weekly basis. This has not been reported for watermelon before.

Frequency of tooth brushing and associated factors in Mexican schoolchildren six to nine years of age.

OBJECTIVE: To determine the prevalence of daily tooth brushing and evaluate some variables associated. SUBJECTS AND METHODS: A cross-sectional study was carried out in 320 schoolchildren six to nine years old in Campeche, Mexico. Information on sociodemographic and socio-economic variables, oral hygiene practices and attitudes were collected through a questionnaire. The frequency of tooth brushing was categorized as "0" = fewer than seven times/week, "1" = at least once a day. In the analysis, nonparametric tests were used. RESULTS: Mean age was 6.99 +/- 1.00 years, 52.5% were boys. The prevalence of daily tooth brushing was 81.6%. In bivariate analysis, the prevalence of tooth brushing was higher (p < 0.05) among the children of mothers with higher schooling (9.80 years vs 8.47 years, p < 0.05), and in younger children (84.6% in 6-7-year olds vs 71.2% in 8-9-year olds, p < 0.05). A slight, non-significant association (p < 0.10) was noted between the current frequency of tooth brushing and an earlier age when the child first started brushing with toothpaste. There were no statistically significant differences (p > 0.05) in the frequency of tooth brushing by gender or by the mother's attitude toward the oral health of her child. CONCLUSIONS: The prevalence of daily tooth brushing was high compared to other studies. Mother's maximum level of schooling (as an indicator of socio-economic position) was associated with higher frequency of tooth brushing. Maternal characteristics are associated with the oral health behaviour of their children.

Association between developmental enamel defects in the primary and permanent dentitions.

AIM: To determine if the presence of developmental enamel defects (DED) in the primary dentition is a risk indicator for the presence of DED in the permanent dentition in children with mixed dentition, as well as others factors. MATERIALS AND METHODS: A cross-sectional study was undertaken in 1296 school children ages six to 72 years. The DED [FDI; 1982] in both dentitions were identified by means of an oral exam scoring enamel opacities [classified as demarcated or diffused], and enamel hypoplasia. Sociodemographic and socioeconomic variables were collected through a questionnaire. Socioeconomic status (SES) was determined based on the occupation and maximum level of education of parents. Statistical analysis included logistic regression. RESULTS: Mean age of participants was 8.40 +/- 1.68; 51.6% were boys. DED prevalence was 7.5% in the permanent dentition and 10.0% in the primary dentition. The logistic regression model, adjusting for sociodemographic and socioeconomic variables, showed that for each primary tooth with DED, the odds of observing DED in the permanent dentition increased 7.38 times [95% CI = 1.17-1.64; p < 0.001]. CONCLUSION: An association between DED presence in both permanent and primary dentitions was observed. Further studies are necessary to fully characterise such relationship.

[Ecologic study in Mexico (2003-2009) on cleft lip and/or palate and associated sociodemographic, socioeconomic and pollution factors]. / Estudio ecológico en México (2003-2009) sobre labio y/o paladar hendido y factores sociodemográficos, socioeconómicos y de contaminación asociados.

OBJECTIVE: To analyze the rates of cleft lip and/or cleft palate (CLP) in Mexico between 2003 and 2009 and assess their association with variables at ecological level, sociodemographic, socioeconomic, and pollution. MATERIAL AND METHODS: An ecological study was conducted with data from the 32 states of Mexico for incidence of CLP, obtained from the Ministry of Health. We included sociodemographic, socioeconomic, and pollution information, obtained from governmental agencies. CLP incidence rates were used as dependent variable; independent variables were socioeconomic, demographic and pollution indicators. Statistical analysis was performed using Spearman correlation and chi(2) tests. RESULTS: During the study period 10573 new cases presented (mean 1510.43 per year). The States with the highest rate (per 1000 births) were: in 2003 the Federal District (Mexico City) (1.76), in 2004 Jalisco (2.62), in 2005 Oaxaca (1.66), in 2006 the State of Mexico (1.29), in 2007, 2008 and 2009 Jalisco (2.17, 2.92, and 1.99). For all the years men were more likely affected than women (P<.05). Variables found positively correlated to LPH rates were total population, solid waste, life expectancy, urban solid waste. The variables negatively correlated were population percentages of high alcohol users, and of alcohol abuse or addiction. CONCLUSIONS: The State of Jalisco was one of the most affected locations over the years. Ecologic positive correlations existed between cleft lip and/or palate and sociodemographic, socioeconomic, and pollution factors. Incidence rate was negatively correlated with alcohol use and abuse. More detailed epidemiological studies are needed to fully characterize risk factors in Mexican populations.