Volcanic soil gas 4He/CO2 ratio: a useful geochemical tool for real-time eruption forecasting

At many dormant volcanoes, magmatic gases are not channeled through preferential degassing routes as fumaroles and only percolate through the flanks of the volcano in a diffuse way. This type of volcanic gas emission provides valuable information, even though the soil matrix contains an important atmospheric component. This study aimed to demonstrate that chemical ratios such as He/CO2 in soil gases provide excellent information on the evolution of volcanic unrest episodes and help forecast the volcanic eruption onset. Before and during the occurrence of the October 2011-March 2012 submarine of El Hierro, Canary Islands, more than 8500 soil He analyses and diffuse CO2 emission measurements were performed. The results show that the soil He/CO2 emission ratio began increasing drastically one month before eruption onset, reaching the maximum value 10 days before. During the eruptive period, this ratio also showed a maximum value several days before the period with the highest magma emission rate. The He/CO2 ratio was also helpful in forecasting the eruption onset. We demonstrate that this tool can be applied in real-time during volcanic emergencies. Our results also encourage a reevaluation of the global He emission from the subaerial volcanism.

Dietary changes across time: Studying the indigenous period of La Gomera using δ13 C and δ15 N stable isotope analysis and radiocarbon dating

OBJECTIVES

This article presents new radiocarbon and isotopic data to provide further information about the diet of the indigenous population of La Gomera and its possible changes across time.

MATERIALS AND METHODS

δ¹³ C and δ¹⁵ N of 53 human and 19 faunal samples from different sites on the island have been obtained and analyzed. Of these, 52 have been radiocarbon dated to provide insight on chronological changes.

RESULTS

Human dates range from the 3rd to 15th centuries AD, while faunal dates range from the 1st to 17th centuries AD. Stable carbon and nitrogen values are significantly different between the human and goat samples and have also a trophic increase of 3.4‰. Although male and female δ¹⁵ N data are not significantly different. Both δ¹³ C and δ¹⁵ N values of both human and animal samples tend to discretely decrease over time.

DISCUSSION

Radiocarbon dates from humans correlate with other dates obtained in the rest of the archipelago. Animal radiocarbon dates generally coincide except for one date, which requires further study. Isotopic δ¹⁵ N data suggest a mix of marine and terrestrial protein consumption in humans, the latter being more abundant given the seasonality of the first. δ¹³ C data also suggest a possible mixed diet in humans, with a predominance of C₃ plants, like Hordeum vulgare, the only grain found in archaeological sites so far. Variations of both δ¹³ C and δ¹⁵ N over time suggest a slight modification on the diet, which could be related to environmental changes.

Volatile organic compounds (VOCs) in solid waste landfill cover soil: Chemical and isotopic composition vs. degradation processes

Landfills for solid waste disposal release to the atmosphere a large variety of volatile organic compounds (VOCs). Bacterial activity in landfill cover soils can play an important role in mitigating VOC emission. In order to evaluate the effects of degradation processes and characterize VOCs composition in landfill cover soil, gases from 60 sites and along 7 vertical profiles within the cover soil were collected for chemical and isotopic analysis at two undifferentiated urban solid waste disposal sites in Spain: (i) Pinto (Madrid) and (ii) Zurita (Fuerteventura, Canary Islands). The CO₂/CH₄ ratios and δ¹³C-CO₂ and δ¹³C-CH₄ values were controlled by either oxidation or reduction processes of landfill gas (LFG). VOCs were dominated by aromatics, alkanes and O-substituted compounds, with minor cyclics, terpenes, halogenated and S-substituted compounds. Degradation processes, depending on both (i) waste age and (ii) velocity of the uprising biogas through the soil cover, caused (i) an increase of degradation products (e.g., CO₂, O-substituted compounds) and (ii) a decrease of degradable components (e.g., CH₄, alkanes, alkylated aromatics, cyclic and S-substituted compounds). Terpenes, halogenated compounds, phenol and furans were unaffected by degradation processes and only depended on waste composition. These results highlight the fundamental role played by microbial activity in mitigating atmospheric emissions of VOCs from landfills. Nevertheless, the recalcitrant behaviour shown by compounds hazardous for health and environment remarks the importance of a correct landfill management that has to be carried out for years after the waste disposal activity is completed, since LFG emissions can persist for long time.

[Construction of model for calculating and recording neonatal weight percentiles]

OBJECTIVES

To construct a model for calculating optimal foetal and neonatal weight curves with a method that allows automatic calculation of the percentile and sequential recording of results.

MATERIAL AND METHODS

A model was constructed for calculating optimal weight and the corresponding percentiles for gestational age and sex from a sample of 23,578 newborns, after excluding cases with diseases. Birth weight was modelled using stepwise multiple regression analysis. Newborns were classified as small or large for gestational age (SGA or LGA) using the proposed model. The resulting classification was compared with those derived from other models designed for Spanish children.

RESULTS

Optimal weight model: 3,311.062+68.074 *sex+143.267 *GE40 -13.481 *GE40(2) - 0.797 *GE40(3)+sex* (5.528 *GE40 - 0.674 *GE40(2) - 0.064 *GE40(3)). (GE, gestational age). Weight percentiles were obtained from standardized data using the coefficient of variation of the optimal weight. The degree of agreement between our model classification and those of the Carrascosa model and Ramos model, with empirical and smooth percentiles, was "almost perfect" (κ=0.866, κ=0.872, and κ=0.876 (P<.001), respectively), and between our model and that proposed by Figueras it was "substantial" (κ=0.720, P<.001).

CONCLUSIONS

The new model is comparable to those used for Spanish children and allows accurate, updated automatic percentile calculation for gestational age and sex. The results can be digitally stored to track longitudinal foetal growth. Free access to the model is offered, together with the possibility of automatic calculation of foetal and neonatal weight percentiles.

Translation and psychometric properties of the kid's eating disorders survey (KEDS)-Spanish version

OBJECTIVE

The objective of this study was to determine the psychometric properties of the Kid s Eating Disorders Survey (KEDS)-Spanish version [Cuestionario infantil para trastornos de la conducta alimentaria (CITCA)].

METHOD

The following instruments were applied to subjects aged 7-17 years: K-SADS-PL-MX, Eating Attitude Test-40 (EAT- 40) and CITCA (Spanish version of the KEDS).

RESULTS

A total of 98 females, age 12.5 + 2.5 (7-17), participated. Cronbach's alpha coefficient for the total of the KEDS was 0.92. The scale items were grouped into two main components, which accounted for 74.4% of the variance. The convergent validity between the Spanish version of the KEDS and the EAT-40 was significant: r = 0.832 (p = 0.01). The criterion validity, on comparing the Spanish version of the KEDS with the K-SADS-PL-MX, was acceptable, with a r = 0.899 (p = 0.01). The test-retest at 15 days was positive: r = 0.967 (p = 0.01).

Risk factors for bacteremia in patients with limb cellulitis

The aim of this study was to identify the risk factors for bacteremia in patients with limb cellulitis. Using the administrative and microbiology laboratory databases of a community teaching hospital, a review was conducted of all cases of community-acquired limb cellulitis that occurred during the period 1997-2004 and in which blood cultures had been performed. A comparison of demographical, clinical, and analytical data of patients with bacteremia versus patients without bacteremia was performed by univariate and multivariate analyses. Of 2,678 patients with cellulitis who presented to the hospital's emergency department, 308 were diagnosed with limb cellulitis and had blood cultures. Of these, 57 (18.5%) had bacteremia. In 24 of the 57 (42.1%) patients with bacteremia, the microorganism isolated in blood cultures was non-group-A beta-hemolytic Streptococcus, and in another 14 (24.6%), the microorganism identified was a gram-negative bacterium. Staphylococcus aureus was determined as the cause of bacteremia in just 6 (10.5%) patients and group A Streptococcus in 2 (3.5%). By logistic regression analysis, the following factors were associated with bacteremia: absence of previous antibiotic treatment (OR 5.3, 95% CI 1.4-20.3), presence of two or more comorbid factors simultaneously (OR 4.3, 95% CI 1.6-11.7), length of illness<2 days OR 2.44, 95% CI 1.07-5.56), and proximal limb involvement (OR 6, 95% CI 3.03-12.04). Patients with limb cellulitis who exhibit any of these characteristics are at increased risk of bacteremia. In such patients, it is imperative that blood cultures be performed.

[Antenatal care in immigrants]

The phenomenon of immigration has had an impact on the health care of the population. The immigrant population in Spain today represents approximately 8% of the total population. The majority of this population proceeds from countries with low income, and its origin and distribution is diverse. The immigrant population is characterised by its being young and healthy, and with a capacity to adapt to changes, but its social, economic and labour conditions are frequently insecure and favour vulnerability to disease. In spite of the number of immigrants of the male sex being globally higher than that of women, the percentage of immigrants of the female sex is growing. This increase of the female immigrant population has resulted in the appearance of specific health care needs, especially with respect to sexual and reproductive health. To which we must add a substantial increase in pathologies prevalent in the countries of origin, such as anaemia, tuberculosis, malnutrition, haemoglobinopathies, consanguinity, hypocalcaemia, hepatitis B and/or C, sexually transmitted infections, infectious diseases transmitted by arthropods, such as Chagas disease and other parasitoses, as well as genital mutilations. The aim of this article is to analyse the factors that make it difficult to control gestation in the immigrant population, as well as to establish guidelines for acting in antenatal care consultations. Insistence is placed on health education and prevention during pregnancy, and consideration is given to the appearance of rare diseases related to some of these groups.

Radioprotective effect of sodium diethyldithiocarbamate (DDC) and S-2-aminoethyl-isothioronicadenosin-5-triphosphate (adeturon) in gamma-irradiated Escherichia coli cells

The effect of sodium diethyldithiocarbamate (DDC) and S-2-aminoethyl-isothiouronicadenosin-5-triphosphate (adeturon) in the induction of Escherichia coli SOS response promoted by gamma-irradiation was studied by measuring the induction of sulA gene and the induction of lambda prophage. Furthermore, as a way of measure the exonuclease activity in gamma-irradiated cells in the presence or absence of both compounds, the DNA degradation was determined. Adeturon did not affected DNA degradation, but inhibited the induction of the SOS functions studied. On the contrary, DDC inhibited DNA degradation as well as the induction of the sulA gene, but enhanced lambda induction in E. coli lysogenic strains. These results indicate that both compounds diminish the DNA damage produced by gamma-irradiation and also suggest that the mechanisms of radioprotection must be different. Thus, radioprotection mediated by DDC should involve free hydroxyl radical scavenging and a minor activity of exonuclease. The enhancement of phage induction in E. coli cells that DDC produces could be attributed to its quelant effect and this would not be not probably directly related to radioprotection. Adeturon, as thiols, may serve also as scavenging agent of free hydroxyl radicals, diminishing indirectly the DNA damage level. In addition, adeturon must interact with DNA in the same form that other aminothiol compounds do it. This interaction, mediated by amino groups of adeturon, may serve to concentrate these compounds near of the DNA damage site, increasing the potential for the thiol portion of the molecule to donate hydrogen, decreasing the damage level on DNA molecule. However, adeturon do not modify the exonuclease activity. Some topic about the possible clinical application of both compounds are discussed.