Consumo de riesgo de alcohol y sentido de vida en adolescentes de 18 a 20 años en Tezontepec de Aldama / Risk consumption of alcohol and its impact on the meaning of life in adolescents aged 18 to 20 in Tezontepec de Aldama

Introducción: el consumo de alcohol aumento en los últimos años en adolescentes, la Organización Mundial de la Salud (OMS) indica que América Latina se posiciona en primer lugar de consumo y México ocupa el décimo lugar, en la población adolescente 38.8 % ha consumido alcohol alguna vez en su vida. Objetivo: conocer el nivel de consumo de riesgo de alcohol y el sentido de vida en los adolescentes de 18 a 20 años de edad de la comunidad de Presas, Tezontepec de Aldama, Hidalgo. Material y métodos: de aplicabilidad básica, cuantitativo, con un nivel de alcance descriptivo; diseño metodológico no experimental (observacional), prolectivo, transversal, prospectivo. Resultados: por medio de la escala dimensional del sentido de vida, 34 participantes refieren tener una búsqueda de sentido de vida expresan, experimentar una vida sin propósito y sin sentido, aunque en ocasiones poseen momentos en los que se sienten orientados. En cuanto, al instrumento de medición AUDIT, 10 participantes refieren tener un alto consumo de alcohol. Conclusión: hoy el alcohol sigue siendo un problema en la comunidad adolescente al mismo tiempo impacta de manera negativa en su sentido de vida.

Introduction: adolescent alcohol consumption has increased in recent years. The World Health Organization (WHO) indicates that Latin America is ranked first in this consumption and Mexico's adolescent population occupies tenth place. 38.8% of them have consumed alcohol at some point in their life as much as you have consumed in the last year. Objective: to know the level of risky alcohol consumption and the meaning of life in adolescents between 18 and 20 years of age in the community of Presas, Tezontepec de Aldama. Material and methods: of basic applicability with a quantitative approach and with a descriptive scope level, with a methodological design; non-experimental (observational), prolective, transversal, prospective. Results: 34 participants report having a search for a sense of life, expressing that they are people who experience a life without purpose and meaning, although sometimes they have moments when they feel oriented. Regarding the results of the AUDIT Measurement Instrument, 10 participants report having a high consumption of alcohol, stating that they are personnel who consume alcohol more frequently. Conclusion: alcohol is still a problem in the community today. Adolescent at the same time negatively impacts their sense of life; since young people who are at risk of alcohol have a low meaning of life

Simulated nitrogen deposition influences soil greenhouse gas fluxes in a Mediterranean dryland.

Soil nitrogen (N) availability is a key driver of soil-atmosphere greenhouse gas (GHG) exchange, yet we are far from understanding how increases in N deposition due to human activities will influence the net soil-atmosphere fluxes of the three most important GHGs: nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2). We simulated four levels of N deposition (10, 20 and 50 kg N ha-1 yr-1, plus unfertilised control) to evaluate their effects on N2O, CH4 and CO2 soil fluxes in a semiarid shrubland in central Spain. After 8 years of experimental fertilisation, increasing N availability led to a consistent increase in N2O emissions, likely due to simultaneous increases in soil microbial nitrification and/or denitrification processes. However, only intermediate levels of N fertilisation reduced CH4 uptake, while increasing N fertilisation had no effects on CO2 fluxes, suggesting complex interactions between N deposition loads and GHG fluxes. Our study provides novel insight into the responses of GHGs to N deposition in drylands, forecasting increases in N2O emissions, and decreases in CH4 uptake rates, with likely consequences to the on-going climate change.

Availability of zinc from infant formula by in vitro methods (solubility and dialyzability) and size-exclusion chromatography coupled to inductively coupled plasma-mass spectrometry.

Zinc bioaccessibility from infant formula was estimated by in vitro methods (solubility and dialyzability) and size-exclusion chromatography (SEC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS). Infant formula samples were first characterized in terms of Zn bound to lipids and proteins and Zn distribution in the aqueous soluble protein fraction. We found that Zn is not incorporated into the lipid fraction of the samples, being mainly associated with the protein fraction (around 100%). Fractionation of Zn-containing proteins in the soluble protein fraction was achieved by SEC-ICP-MS after performing protein extraction with a solution of 100mM (pH 6.8) Tris-HCl. The percentages of zinc in the soluble protein fraction in the soy-based and lactose-free infant formula were very low, around 7 and 24%, respectively, whereas the content of Zn in the soluble protein fraction of milk-based formula was around 90%. By SEC-ICP-MS, we found that Zn is associated with low-molecular weight compounds (around 10kDa) in all the infant formulas tested. The percentages of Zn estimated in the in vitro gastrointestinal digests of the infant formula ranged from 30 to 70% and from 1 to 10% for solubility and dialyzability assays, respectively. The dialyzability test resulted in lower than expected scores, as SEC-ICP-MS analysis of the gastrointestinal extracts revealed that Zn is bound to biomolecules with a molecular weight ranging from 1 to 7kDa, which suggests that dialysis data should be interpreted with caution. Speciation studies are a valuable tool for establishing availability of nutrients and for validating data from dialyzable in vitro methods.

Biogeochemical indicators of elevated nitrogen deposition in semiarid Mediterranean ecosystems.

Nitrogen (N) deposition has doubled the natural N inputs received by ecosystems through biological N fixation and is currently a global problem that is affecting the Mediterranean regions. We evaluated the existing relationships between increased atmospheric N deposition and biogeochemical indicators related to soil chemical factors and cryptogam species across semiarid central, southern, and eastern Spain. The cryptogam species studied were the biocrust-forming species Pleurochaete squarrosa (moss) and Cladonia foliacea (lichen). Sampling sites were chosen in Quercus coccifera (kermes oak) shrublands and Pinus halepensis (Aleppo pine) forests to cover a range of inorganic N deposition representative of the levels found in the Iberian Peninsula (between 4.4 and 8.1 kg N ha(-1) year(-1)). We extended the ambient N deposition gradient by including experimental plots to which N had been added for 3 years at rates of 10, 20, and 50 kg N ha(-1) year(-1). Overall, N deposition (extant plus simulated) increased soil inorganic N availability and caused soil acidification. Nitrogen deposition increased phosphomonoesterase (PME) enzyme activity and PME/nitrate reductase (NR) ratio in both species, whereas the NR activity was reduced only in the moss. Responses of PME and NR activities were attributed to an induced N to phosphorus imbalance and to N saturation, respectively. When only considering the ambient N deposition, soil organic C and N contents were positively related to N deposition, a response driven by pine forests. The PME/NR ratios of the moss were better predictors of N deposition rates than PME or NR activities alone in shrublands, whereas no correlation between N deposition and the lichen physiology was observed. We conclude that integrative physiological measurements, such as PME/NR ratios, measured on sensitive species such as P. squarrosa, can provide useful data for national-scale biomonitoring programs, whereas soil acidification and soil C and N storage could be useful as additional corroborating ecosystem indicators of chronic N pollution.

Nitrogen deposition effects on Mediterranean-type ecosystems: an ecological assessment.

We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling.

Stability of inorganic mercury and methylmercury on yeast-silica gel microcolumns: field sampling capabilities.

The stability of methylmercury and inorganic mercury retained on yeast-silica gel microcolumns was established and compared with the stability of these species in solution. Yeast-silica gel columns with the retained analytes were stored for two months at three different temperatures: -20 degrees C, 4 degrees C and room temperature. At regular time intervals, both mercury species were eluted and quantified by cold vapor atomic absorption spectrometry (CVAAS). Methylmercury was found stable in the columns over the two-month period at the three different temperatures tested while the concentration of inorganic mercury decreased after one week's storage even at -20 degrees C. These results are of great interest since the use of these microcolumns allows the preconcentration and storage of mercury species until analysis, thus saving laboratory space and avoiding the problems associated with maintaining species integrity in aqueous solution.

Availability of organic and inorganic phosphorus compounds as phosphorus sources for Carex species.

Inorganic phosphates (ferric phosphate, calcium phosphate and aluminium phosphate) and organic forms of phosphorus (inosito) hexaphosphate and ß-glycerophosphate) were tested as phosphorus (P) sources for the growth of three Carex species from fens differing in productivity- and nutrient availability. Aluminium phosphate and ß-glycerophosphate were equally effective sources of P for all three Carex species as KH2 PO4 , which was used as a control treatment. Phosphorus from ferric phosphate and calcium phosphate was also taken up bv Carex acutiformis Ehrh., a species of high productivity from eutrophic fen areas, but not by the other two species. Only Carex lasiocarpa Ehrh., a species from P-limited fens, showed a higher P-uptake when grown with inositol phosphate than in the second control treatment without P. The P-source also affected, with differences between species, the biomass allocation to the below-ground plant parts and the area of absorption surface of the roots. The mobilization of organic sources of P by fen Carex species found in the present study might be an important factor in the P dynamics of fens because of the high contents of organic P in the fen peat soils where these species grow. In the same way, the utilization of inorganic sources of P can play a relevant role in the P-cycle in these systems where the discharge of ground water rich in ions can lead to the fixation of P into inorganic compounds. However, the differing abilities of the various Carex species to mobilize P from P-pools does not explain clearly their preferential presence in different fens in relation to the P-availability.