Connectivity and hydrological efficiency dynamics at active volcanoes, Mexico.

Connectivity is an emergent property that describes how complex topography favors or impedes sediment transfer processes. In active volcanic areas, high connectivity may lead to extremely efficient processes, such as lahars. The aim of the present study is to examine the behavior (activation-deactivation) of sub-basins affected by volcanic and anthropogenic processes by studying the changes in connectivity and hydrological efficiency. Two volcanic zones in Mexico were selected: Volcán de Colima and Popocatépetl volcano, the two most active and dangerous volcanoes in the country. The joint index of connectivity (ICJ) and lateral hydrological efficiency index (LHEI) were calculated for both volcanic areas in basins recently affected by eruptive activity (Volcán de Colima) and co-seismic landslides (Popocatépetl). The analyses enabled the identification of eleven recently activated sub-basins (3.82 km2) at the Volcán de Colima and fifteen (3.77 km2) at the Popocatepetl volcano, as a consequence of natural processes and economic activities. Critical thresholds indicating the percentage area of land cover/use at which a sub-basin reaches high or very high LHEI values and the percentage of land cover/use change required for a sub-basin to modify its behavior (activation-deactivation) were identified using classification trees. The holistic capacity of the concepts of connectivity and hydrological efficiency permits analyzing the spatiotemporal variations of sediment transport based on the interactions between the hydrogeomorphological dynamics of volcanic processes and the territorial impact of socio-economical activities. Through this approach, new active areas have been identified in both volcanoes; the knowledge of the processes that occurred in these areas represents a key factor for hazard and risk assessment for the population in the near future.

Attention to metabolic hunger and its effects on Helicobacter pylori infection.

A significant decrease in the bacterial count of small intestinal mucosa has been observed in children with recurrent diarrhea or abdominal pain in the time that has elapsed from the previous meal. Humans may be trained to recognize metabolic feelings of hunger that are associated with a steady and slightly lower glycemia than baseline, between 4.7 and 3.9 mmol/L (intervention). An eating habit associated with a decrease in preprandial glycemia prevented diarrhea relapses, and was expected to impair intestinal microflora growth, including Helicobacter pylori in the stomach. The development of Helicobacter pylori infection might be prevented during childhood, and recovery from infection may be expected with intervention. The improvement in attention to metabolic feelings consisted of acquiring a predictive ability of glycemia by distinction between unsolicited hunger feelings (metabolic hunger) and those associated with external cues. Matching intake to the inbetween energy needs served to predict the subsequent emergence of the metabolic hunger. The matching was further compensated for the early or late emergence of metabolic hunger at the subsequent meals. Fruit and vegetables were increased to avoid abrupt glycemia lowering. This intervention was trained in 5-month periods. Subjects (209, 44, and 58) completed their training during 4-year periods between 1982 and 1994, and were enrolled in a prospective, controlled, randomized, interventional, preventive, and cohort study. The "prevention" hypothesis was tested in a subgroup of 86 healthy infants who were recalled in the years 1996 to 1998. A "recovery" study of approximately a 1-year intervention was investigated in 47 healthy subjects between ages 5 and 25, who were positive for anti-H. pylori and had no need for an immediate antibiotic treatment at entry. The following behavioral factors were recorded in a 7-day home diary and calculated: the fraction of meals induced by metabolic hunger out of 21 main mealtimes; average preprandial glycemia (DAP glycemia); daily intakes, activity; and bedtime hours. The decrease in preprandial glycemia was the objective measure of compliance with the recognition of "metabolic" hunger. Anthropometric measures and blood tests were obtained for nutritional and functional verifications. Average preprandial glycemia was 8.5 and 8.6% lower in the intervention groups than the control groups in the "prevention" and "recovery" studies, respectively, at the end of follow-up (p<0.05 and <0.001, respectively). A 4.7% seroprevalence of H. pylori infection was observed in the intervention group, with 30.2% in the control group at a mean age of 10 years after approximately an 8-year follow-up in the "prevention" study (p<0.0005). The seroprevalence decreased to 9 of 24 (37.5%) under intervention as opposed to 20 of 23 controls (87%) in the recovery study (p<0.002). A significant positive correlation was found between DAP glycemia and the anti-H. pylori serum antibody concentration (r = 0.52; p = 0.0002). A decrease in the level of immune stimulation by H. pylori infection was observed due to the intervention, which may have a preventive and therapeutic role on the infection.

[Behavior of alpha 1-acid glycoprotein in the premature infant]. / Comportamento dell'alfa 1 glicoproteina acida nel bambino dismaturo.

The interest of clinicians has recently turned to the study of acute phase proteins whose determination, especially in the newborn, offers not only diagnostic information, but also information about prognosis. For many years we have been interested in the study of orosomucoid behaviour in newborn term babies and in low weight premature babies. For this purpose 113 patients were tested, divided into different gestational age groups, from which samples were taken immediately after birth, on the following days and before beginning any kind of treatment to show the behaviour of acid glycoprotein until normal average values were reached. Statistical processing of the data showed an average orosomucoid value in newborn term babies in perfect agreement with the literature. There was correlation among gestational age, weight at birth and orosomucoid concentration, which peaked more quickly the greater the gestational age and weight at birth. Thereafter, the concentration decreased until it stabilised at average term newborn values.

Evaluation of GH secretion.

The Authors analyse the main body of somatotropin function test: insulin hypoglycemia; arginine; ornithine; I-dopa; clonidine; galanin; GH-RH; physical exercise; sleep; combined stimuli; spontaneous GH secretion of varying duration. The advantages and disadvantages of the different tests are pointed out and some recent contradictory findings concerning the newest prolonged techniques are reported. The Authors claim priority for the clinical/auxological examination, with measurement of bone age and growth velocity and suggest the procedure for GH deficit diagnosis to be followed, also in the light of their personal experience.

[Statistico-mathematical correlation of the B and C isoenzyme ratio of carbonic anhydrase and fetal hemoglobin, and its probable biological significance in the metabolism of zinc]. / Considerazioni sulla correlazione statistico-matematica tra rapporto isoenzimi "B" e C" dell'anidrasi carbonica ed emoglobina fetale e suo probabile significato biologico nel metabolismo dello zinco.

The AA. performed a study on the Bravais-Galton's correlation coefficient. They applied this coefficient to the HCAB/HCAC ratio and to the fetal haemoglobin often groups of twenty children (one month four years old) values. The result support the assumption that there is a strong biochemical relationship between zinc-carbonic anhydrase and haemoglobin in erithrocytes.

["Preparative" chromatographic fractionation of human carbonic anhydrase isoenzymes. Specific studies on their identification]. / Frazionamento cromatografico "preparativo" degli isoenzimi dell'anidrasi carbonica umana. Studi specifici per la loro identificazione

The AA. describe a technique for chromatographic fractionation of the isoenzymes of carbonic anhydrase. They utilized a hydroxylapatite column, soaking the isoenzymes suspension at its top. As eluting solutions they utilized a series of phosphate buffers, pH 6,8, at increasing ionic strength. The elution, allowed the separation of three fractions which the AA. identified by spectrophotometric, electrophoretic and immunologic analysis and by atomic absorption spectrophotometry. -- Electrophoretic analysis showed that the "first fraction" eluted from the chromatographic column corresponding to the first peak, contained 8,5% of total protein, the "second chromatographic fraction", corresponding to the second electrophoretic peak contained 82,5%, whereas the "third" contained 9%. -- Nitrogen contents in the three eluted fractions showed the following values: 6,6% in the first fraction, 85,5% in the second, 8% in the third. These values are very near the ones obtained from ferogram. -- Spectrophotometric analysis revealed similar structure for the three fraction, in the range 230-300 nm of spectrum and a second peak at 400 nm for the third eluted fraction. -- The atomic spectrophotometric absorption revealed the presence of zinc in the three fractions, the amount of the element resulted almost constantly related to the nitrogen concentration in each of them.