Computer-assisted cartography using topographic properties: precision and accuracy of local soil maps in central Mexico

Map units directly related to properties of soil-landscape are generated by local soil classes. Therefore to take into consideration the knowledge of farmers is essential to automate the procedure. The aim of this study was to map local soil classes by computer-assisted cartography (CAC), using several combinations of topographic properties produced by GIS (digital elevation model, aspect, slope, and profile curvature). A decision tree was used to find the number of topographic properties required for digital cartography of the local soil classes. The maps produced were evaluated based on the attributes of map quality defined as precision and accuracy of the CAC-based maps. The evaluation was carried out in Central Mexico using three maps of local soil classes with contrasting landscape and climatic conditions (desert, temperate, and tropical). In the three areas the precision (56 %) of the CAC maps based on elevation as topographical feature was higher than when based on slope, aspect and profile curvature. The accuracy of the maps (boundary locations) was however low (33 %), in other words, further research is required to improve this indicator.

Chagas disease in Mexico: an analysis of geographical distribution during the past 76 years - A review

Literature from 1928 through 2004 was compiled from different document sources published in Mexico or elsewhere. From these 907 publications, we found 19 different topics of Chagas disease study in Mexico. The publications were arranged by decade and also by state. This information was used to construct maps describing the distribution of Chagas disease according to different criteria: the disease, vectors, reservoirs, and strains. One of the major problems confronting study of this zoonotic disease is the great biodiversity of the vector species; there are 30 different species, with at least 10 playing a major role in human infection. The high variability of climates and biogeographic regions further complicate study and understanding of the dynamics of this disease in each region of the country. We used a desktop Genetic Algorithm for Rule-Set Prediction procedure to provide ecological models of organism niches, offering improved flexibility for choosing predictive environmental and ecological data. This approach may help to identify regions at risk of disease, plan vector-control programs, and explore parasitic reservoir association. With this collected information, we have constructed a data base: CHAGMEX, available online in html format.

Distribution and agroclimatic characterization of potential cultivation regions of physic nut in Mexico

The purposes of this study were to determine the distribution and climatic patterns of current and future physic nut (Jatropha curcas) cultivation regions in Mexico, and to identify possible locations for in vivo germplasm banks establishment, using geographic information systems. Current climatic data were processed by Floramap software to obtain distribution maps and climatic patterns of regions where wild physic nuts could be found. DIVA-GIS software analyzed current climatic data (Worldclim model) and climatic data generated by CCM3 model to identify current and future physic nut cultivation regions, respectively. The distribution map showed that physic nut was present in most of the tropical and subtropical areas of Mexico, which corresponded to three agroclimatic regions. Climate types were Aw2, Aw1, and Bs1, for regions 1, 2 and 3, respectively. Nontoxic genotypes were associated with region 2, and toxic genotypes were associated with regions 1 and 3. According to the current and future cultivation regions identified, the best suitable ones to establish in vivo germplasm collections were the coast of Michoacán and the Isthmus of Tehuantepec, located among the states of Veracruz, Oaxaca and Chiapas.

Pagamento de proventos versus preços deações maduras e em expansão segundo Kohonen Maps

Este estudo investiga se a política de distribuição de resultados seria capaz de alterar os preços das ações de uma empresa. O objetivo deste trabalho é discutir os impactos do pagamento de proventos sobre os preços das ações, na data ex direito, de empresas maduras e de empresas em expansão, considerando-se ainda o efeito da classe da ação (ordinária ou preferencial) sobre os resultados. Para tal, adotou-se a metodologia de dados em painel, segmentando a amostra a partir dos Mapas Auto-organizáveis de Kohonen. Os resultados revelam que a estratégia de curto prazo de comprar ações na última data com, vender na primeira data ex e embolsar os dividendos é capaz de gerar perdas de capital que superam em até quatro vezes o ganho líquido decorrente do provento embolsado.

Muertes por homicidio, consecuencia fatal de la violencia: el caso de Mexico, 1979-1992

Se analizaron las muertes registradas como homicidio en México de 1979-1992. El estudio se basó en fuente secundaria, siendo las variables analizadas: año, edad, sexo y causa externa de traumatismos y envenenamientos según CIE IX Rev.(E960-E969). Se utilizó un modelo de regresión Poisson para las causas más frecuentes, obteniendo riesgos relativos según edad y sexo. El grupo de referencia fue el de 10-14 años y el sexo femenino. Se registraron 198,485 muertes por Homicidio, con un promedio anual de 14,177 y diario de 39. La principal causa fue ataque con arma de fuego y explosivos(56%). El riesgo relativo más alto fue para el grupo de 35-39 años, con RR 15,4 IC(95%) 14,9-16,0, en comparación al de referencia. El sexo masculino presentó un riesgo relativo 10,1 veces mayor que el femenino, ajustado por edad IC10.0-10.3. Los resultados llaman la atención sobre la necesidad de profundizar y analizar el problema de los homicidios bajo una perspectiva multidisciplinaria.

Effects of health decentralization, financing and governance in Mexico

OBJECTIVE: To identify the effects of decentralization on health financing and governance policies in Mexico from the perspective of users and providers. METHODS: A cross-sectional study was carried out in four states that were selected according to geopolitical and administrative criteria. Four indicators were assessed: changes and effects on governance, financing sources and funds, the final destination of resources, and fund allocation mechanisms. Data collection was performed using in-depth interviews with health system key personnel and community leaders, consensus techniques and document analyses. The interviews were transcribed and analyzed by thematic segmentation. RESULTS: The results show different effectiveness levels for the four states regarding changes in financing policies and community participation. Effects on health financing after decentralization were identified in each state, including: greater participation of municipal and state governments in health expenditure, increased financial participation of households, greater community participation in low-income states, duality and confusion in the new mechanisms for coordination among the three government levels, absence of an accountability system, lack of human resources and technical skills to implement, monitor and evaluate changes in financing. CONCLUSIONS: In general, positive and negative effects of decentralization on health financing and governance were identified. The effects mentioned by health service providers and users were related to a diversification of financing sources, a greater margin for decisions around the use and final destination of financial resources and normative development for the use of resources. At the community level, direct financial contributions were mentioned, as well as in-kind contributions, particularly in the form of community work.

Economic burden of expected epidemiological changes in diseases related to tobacco, Mexico

OBJECTIVE: To determine health care costs and economic burden of epidemiological changes in diseases related to tobacco consumption. METHODS: A time-series analysis in Mexico (1994-2005) was carried out on seven health interventions: chronic obstructive pulmonary diseases, lung cancer with and without surgical intervention, asthma in smokers and non-smokers, full treatment course with nicotine gum, and full treatment course with nicotine patch. According with Box-Jenkins methodology, probabilistic models were developed to forecast the expected changes in the epidemiologic profile and the expected changes in health care services required for selected interventions. Health care costs were estimated following the instrumentation methods and validated with consensus technique. RESULTS: A comparison of the economic impact in 2006 vs. 2008 showed 20-90% increase in expected cases depending on the disease (p<0.05), and 25-93% increase in financial requirements (p<0.01). The study data suggest that changes in the demand for health services for patients with respiratory diseases related to tobacco consumption will continue showing an increasing trend. CONCLUSIONS: In economic terms, the growing number of cases expected during the study period indicates a process of internal competition and adds an element of intrinsic competition in the management of preventive and curative interventions. The study results support the assumption that if preventive programs remain unchanged, the increasing demands for curative health care may cause great financial and management challenges to the health care system of middle-income countries like Mexico.

Vision antropologica de la descentralizacion del sistema de salud en Mexico

OBJETIVO: Analizar cambios organizacionales, políticos y económicos resultantes de la descentralización del sistema de salud en la población sin seguridad social en México. METODOS: Se visitaron tres estados del país seleccionados por el número de habitantes en condición de pobreza, el partido político en el poder y la etapa de implementación de la descentralización (la primera fue en 1984 y la segunda en 1997). Se realizaron entrevistas durante 2007 con informantes clave de los servicios de salud de los gobiernos estatales, personas que acudieron a consulta en los servicios estatales de salud y líderes comunitarios. Los datos fueron analizados desde una perspectiva antropológica y económica. RESULTADOS: La descentralización ocurrió de forma heterogénea en cada estado, observándose una transferencia de responsabilidades de la federación a los estados, más no así una ruptura con la dependencia del nivel central - federal. Las reformas impulsadas desde el nivel federal para crear un esquema fundamentado en principios de subsidiaridad financiera y democratización en salud enfrentan retos políticos y organizacionales para su consolidación. CONCLUSIONES: El enfoque antropológico muestra la relevancia de considerar factores organizacionales, políticos y económicos como parte del proceso de descentralización.

Tele-asistencia y tele-alarma para adultos mayores: experiencias preliminares en Mexico

OBJETIVO Analizar el efecto de un programa piloto de tele-asistencia y tele-alarma en la autopercepción del estado de salud de los adultos mayores y conocer la satisfacción y aceptación del programa. METODOS Estudio transversal que incluyó entrevistas a 378 adultos mayores, 294 cuidadores/familiares y 53 profesionales de la salud, realizado en la Ciudad de México en 2010. Variables sociodemográficas, de autopercepción del estado de salud, satisfacción y aceptación del programa se obtuvieron por medio de cuestionario estandarizado. Se realizó análisis descriptivo y se utilizaron pruebas no paramétricas. RESULTADOS Se observaron efectos significativos en la autopercepción del estado de salud, 6,17 (DE 17,9 p < 0,05) puntos por encima de la media. El programa tuvo una buena aceptación por parte de los adultos mayores, de sus cuidadores familiares y de los profesionales de la salud. CONCLUSIONES El programa contribuye a mantener o mejorar la calidad de vida, permite la atención preventiva y es un medio ideal para dar apoyo psicosocial a los adultos mayores.

Population dynamics and biting rhythm of the anthropophilic sandfly Lutzomyia cruciata (Diptera: Psychdidae) in Southeast, Mexico

Sandflies attracted by human bait were caught in an endemic focus of localized cutaneous leishmaniasis in the state of Campeche, Mexico. Catches were carried out monthly from February 1994 to January 1995 between 18:00 and 22:00 h. Lutzomyia cruciata was the only species caught. The highest population peak of Lu. cruciata was found in March with lesser peaks in February, December 1994, and January 1995. Maximum biting rate of Lu. cruciata was found between 18:00 and 19:00 h. The host-seeking females of Lu. cruciata were directly related to levels of humidity between 88 and 100%. Low and high temperature had a negative effect upon Lu. cruciata activity. The possible role of Lu. cruciata as vector of leishmaniasis in the state of Campeche, Mexico is discussed.

Infection by Trypanosoma cruzi in mammals in Yucatan, Mexico: a serological and parasitological study

In order to determine Trypanosoma cruzi infection among mammals in Yucatan, Mexico, 372 animals, both wild and synanthropic including carnivores, marsupials and rodents were studied. Serological studies by indirect haemagglutination (IHA) were carried out to detect antibodies to T. cruzi and a parasitological study was also performed (blood smear and histopathology). Of all the animals tested 18.54% were serologically positive, with a significantly higher frequency among the wild ones (33.33%) compared to the synanthropic ones (17.79%). To determine T. cruzi in positive animals, blood was inoculated into a white mouse (webster type) to prove myocardium colonization. The serological and parasitological positivity of these animals, as well as their behavior in the environment, taken together with the socioeconomic and cultural characteristics of the population, suggest that in Yucatan, Mexico, Canis familiaris, Didelphis marsupialis and Rattus rattus act as a link with the wild cycle.

The histopathology of cutaneous leishmaniasis due to Leishmania (Leishmania) mexicana in the Yucatan peninsula, Mexico

Localized Cutaneous Leishmaniasis (LCL) known as "chiclero's ulcer" in southeast Mexico, was described by SEIDELIN in 1912. Since then the sylvatic region of the Yucatan peninsula has been documented as an endemic focus of LCL. This study of 73 biopsies from parasitological confirmed lesions of LCL cases of Leishmania (Leishmania) mexicana infection was undertaken: 1) to examine host response at tissue level; and 2) to relate manifestations of this response to some characteristics of clinical presentation. Based on Magalhães' classification we found that the most common pattern in our LCL cases caused by L. (L.) mexicana was predominantly characterized by the presence of unorganized granuloma without necrosis, (43.8%). Another important finding to be highlighted is the fact that in 50/73 (68.5%) parasite identification was positive. There was direct relation between the size of the lesion and time of evolution (r s = 0.3079, p = 0.03), and inverse correlation between size of the lesion and abundance of amastigotes (r s = -0.2467, p = 0.03). In view of the complexity of clinical and histopathological findings, cell-mediated immune response of the disease related to clinical and histopathological features, as so genetic background should be studied.

Comparative analysis of two-dimensional electrophoresis maps (2-DE) of Helicobacter pylori from Brazilian patients with chronic gastritis and duodenal ulcer: a preliminary report

Helicobacter pylori is a bacterium recognized as the major cause of peptic ulcer and chronic gastritis. Recently, a proteome-based approach was developed to investigate pathogenic factors related to H. pylori. In this preliminary study, H. pylori strains were isolated from gastric biopsies of patients with chronic gastritis and duodenal ulcers. A partial proteomic analysis of H. pylori strains was performed by bacterial lyses and proteins were separated by two-dimensional gel electrophoresis (2-DE). A comparative analysis was performed to verify a differential protein expression between these two 2-DE maps. These data should be useful to clarify the role of different proteins related to bacterial pathogenesis. This study will be completed using a larger number of samples and protein identification of H. pylori by MALDI-TOF mass spectrometry.

Seroprevalence of selected viral, bacterial and parasitic infections among inpatients of a public psychiatric hospital of Mexico

We sought to determine the frequency of serological markers of selected infections in a population of psychiatric patients in Durango City, Mexico, and to determine whether there are any epidemiological characteristics of the subjects associated with the infections. One hundred and five inpatients of a public psychiatric hospital of Durango were examined for HBsAg, anti-HCV antibodies, anti-HIV antibodies, anti-Brucella antibodies, rapid plasma reagin and anti-Cysticercus antibodies by commercially available assays. Anti-Cysticercus antibodies were confirmed by Western blot and HBsAg by neutralization assay. Epidemiological data from each participant were also obtained. Seroprevalences of HBsAg, anti-HCV, anti-HIV, anti-Brucella, rapid plasma reagin and anti-Cysticercus antibodies found were 0.0%, 4.8%, 0.9%, 0.0%, 1.9%, and 0.9%, respectively. Overall, 9 (8.6%) inpatients showed seropositivity to any infection marker. We concluded that our psychiatric inpatients have serological evidence of a number of infections. HCV is an important pathogen among our psychiatric inpatients. Health care strategies for prevention and control of infections in Mexican psychiatric patients should be considered.

Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico

In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.