Uncertainties Associated with Arithmetic Map Operations in GIS.

Arithmetic map operations are very common procedures used in GIS to combine raster maps resulting in a new and improved raster map. It is essential that this new map be accompanied by an assessment of uncertainty. This paper shows how we can calculate the uncertainty of the resulting map after performing some arithmetic operation. Actually, the propagation of uncertainty depends on a reliable measurement of the local accuracy and local covariance, as well. In this sense, the use of the interpolation variance is proposed because it takes into account both data configuration and data values. Taylor series expansion is used to derive the mean and variance of the function defined by an arithmetic operation. We show exact results for means and variances for arithmetic operations involving addition, subtraction and multiplication and that it is possible to get approximate mean and variance for the quotient of raster maps.

Análisis de contenido y lingüística computacional: su rapidez, confiabilidad y perspectivas / Content analysis and computational linguistics: its quickness, reliability and perspectives

El análisis de contenido es una técnica que convierte las respuestas abiertas de entrevistas en categorías. Este proceso es de gran utilidad dado que define las categorías de un estudio sobre la base de la percepción de la muestra, evitando la imposición de categorías creadas por el investigador. Sin embargo, este tipo de análisis conlleva un alto costo de tiempo, recursos y personal especializado. Programas como el ATLAS.ti o el NVivo no constituyen una solución eficaz ni eficiente. Los nuevos programas basados en lingüística computacional ofrecen un escenario diferente, dado que el programa "entiende e interpreta" las categorías. Para comprobar su eficacia y eficiencia se compara un análisis de contenido hecho por expertos con el análisis utilizando el programa SPSS Text Analytics for Surveys (TA). Se concluye que bajo la supervisión de un investigador especializado, siguiendo ciertos pasos de afinamiento de la extracción, el TA permite un ahorro de tiempo importante, una mayor confiabilidad y abre las posibilidades para análisis cualitativos con muestras grandes

Content analysis is a technique that converts open-ended responses into categories. This process is of great value since it defines the categories of a study based on the perception of the sample, avoiding imposed categories created by the researcher. However, this type of analysis involves extensive use of time, resources, and expertise. Programs such as ATLAS.ti or NVivo do not constitute an effective nor efficient solution. New software based on computational linguistics offers a different scenario, as it allows the "understanding and interpretation" of categories. In order to prove its effectiveness and efficiency, content analysis made by experts is compared with analysis using SPSS Text Analytics for Surveys (TA). We conclude that under the supervision of a specialized researcher, TA allows for an important time saving, increased reliability, and opens up possibilities for qualitative analysis of large samples

[Liraglutide and glimepiride on glycaemic control in type 2 diabetes in the Mexican cohort (LEAD 3)]. / Liraglutida y glimepirida para el control glucémico de la diabetes tipo 2. Análisis de la cohorte mexicana de LEAD-3.

OBJECTIVE: To compare the efficacy of liraglutide monotherapy with glimepiride monotherapy in subjects with DM2 inadequately controlled by previous treatment of diet/exercise or oral antidiabetic drug. METHODS: A 52-week, double-blinded, active-controlled, parallel-group, multi-centre, prospective trial, involving 746 subjects was conducted in the USA and Mexico. In Mexico, 171 subjects were rando-mised (1:1:1) to once daily liraglutide (either 1.2, or 1.8 mg/day injected subcutaneously) or glimepiride (8 mg/day orally). RESULTS: Hb1Ac reduced by 0.64%, 1.31% and 0.30% with glimepiride, liraglutide 1.8 mg and 1.2 mg, respectively. Body weight decreased with both liraglutide doses while a weight gain of 0.94 kg was observed with glimepiride. FPG reduced by 27.9 mg/dL with liraglutide 1.8 mg, whereas a FPG increase of 9.54 mg/dL was shown with glimepiride. No major hypoglycaemic episodes were reported in this trial. CONCLUSIONS: in Mexican subjects with DM2, liraglutide monotherapy can provide greater reduction in HbA1c, weight loss and lower risk of hypoglycaemia in comparison with glimepiride.

A record of Permian subaqueous vent activity in southeastern Brazil.

The remarkable occurrence of more than 4,500 conical siliceous mounds in an area of less than 1.5 square kilometres has been reported in the Paraná basin, near Anhembi, São Paulo, in southeastern Brazil. These structures, which are up to two metres high, are thought to have been formed at the margin of a very shallow, broad but waning internal sea, and it was originally suggested that they are stromatolites. Yet their restricted occurrence, unusual abundance and nearly pure siliceous composition have never been satisfactorily explained by this hypothesis. Here we report field and laboratory observations on their shape, construction, composition and mineralogy. On the basis of our data we suggest that the conical mounds are the result of subaqueous Late Permian vent activity in southwestern Gondwana. The present siliceous cone field differs considerably from other Palaeozoic siliceous hot spring deposits, such as those at Rhynie, Scotland, and the Drummond basin, Australia, and therefore represents an unusual occurrence of vent activity.

Use of sibutramine in overweight adult hispanic patients with type 2 diabetes mellitus: a 12-month, randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: The management of type 2 diabetes mellitus is complicated by the presence of risk factors related to overweight and obesity, particularly visceral adiposity. However, weight loss and weight maintenance are difficult for patients with diabetes, and the benefits of dietary modifications are typically modest. Sibutramine is a serotonin- and norepinephrine-reuptake inhibitor that reduces food intake by inducing early satiety and attenuates the decrease in basal energy expenditure associated with weight loss. Previous trials of sibutramine in overweight and obese patients with type 2 diabetes have shown significant weight loss accompanied by better glycemic control. OBJECTIVE: The goal of this study was to assess the effect on body weight and glycemic control of sibutramine in combination with glibenclamide in obese Hispanic patients with type 2 diabetes. METHODS: This was a 12-month, randomized, double-blind, placebo-controlled clinical trial conducted at the Endocrinology Service, General Hospital of Mexico, Mexico City. Included were overweight or obese (body mass index [BMI] >27 kg/M2) patients with type 2 diabetes between the ages of 24 and 65 years who had been receiving glibenclamide monotherapy for at least 2 weeks and whose glucose concentrations were stable. Patients were randomized to receive sibutramine 10 mg or placebo once daily. The primary efficacy measures were change in body weight, waist circumference, and glycosylated hemoglobin (HbA1c). Anthropometrics and fasting glucose concentrations were measured monthly. HbA1c was determined at baseline and at 6 and 12 months. Laboratory parameters were measured at baseline and at the end of the study. RESULTS: Forty-four patients were randomized to receive sibutramine (28 women, 16 men; mean [SD] age, 47.6 [9.0] years), and 42 were randomized to receive placebo (31 women, 11 men; mean age, 45.8 [8.1] years). Twenty-four patients in the sibutramine group and 23 in the placebo group completed the trial. In the sibutramine group, body weight was reduced from a mean (SD) of 73.9 (10.3) kg at baseline to 69.8 (10.6) kg at month 12; BMI decreased from 29.9 (2.6) to 28.2 (2.9) kg/M2; waist circumference was reduced from 94.9 (8.4) to 90.8 (8.4) cm; the plasma fasting glucose concentration decreased from 140.4 (29.4) to 114.2 (32.0) mg/dL; and the HbA1c value was reduced from 8.9% (1.2) to 8.3% (1.2) (all, P < 0.001). In the placebo group, the corresponding changes were from 74.5 (10.3) kg at baseline to 73.1 (11.2) kg at month 12; from 30.1 (2.5) to 29.5 (2.9) kg/M2; from 94.4 (7.3) to 93.1 (8.3) cm (P < 0.05); from 140.7 (25.2) to 123.9 (38.3) mg/dL (P < 0.05); and from 9.0% (1.2) to 9.1% (1.3). In the sibutramine group, weight loss continued for up to 12 months. CONCLUSION: In this population of obese Hispanic patients with type 2 diabetes, sibutramine combined with glibenclamide therapy achieved weight loss for up to 12 months and was associated with better glycemic control than placebo.