Estudo aerobiológico da atmosfera de Caxias do Sul em 2007 / Aerobiology study of the atmosphere of Caxias do Sul in 2007

Objetivos: Identificar e quantificar os tipos polínicos na atmosfera de Caxias do Sul e as oscilações estacionais dos grãos de pólen no ano de 2007. Analisar as correlações entre os parâmetros meteorológicos e as concentrações de pólen atmosférico. Métodos: Para a obtenção dos grãos de pólen, foi utilizado o captador volumétrico de sucção tipo Hirst (modelo Burkard) instalado no alto do Hospital Geral, a uma altura aproximada de 20 metros, local este que não apresentam obstáculos aparentes que possam bloquear a chegada de massa de ar. Resultados: Obtivemos como resultados 14.436 grãos de pólen/m3 coletados no ano de 2007. Foram encontradas concentrações máximas mensais bastante diferenciadas, uma na primavera devida, principalmente, a floração de Euphorbiaceae, Urticaceae, Poaceae, Myrtaceae e Carya e outra no inverno que se deve fundamentalmente a floração de plantas arbóreas como Mimosa scabrella, Cupressaceae, Pinaceae, Platanus e Melastomataceae. Em relação aos fatores meteorológicos e as concentrações de pólen liberados pelas plantas, podemos dizer que a temperatura e a precipitação são responsáveis diretos das grandes mudanças quantitativas dos grãos pólen. Conclusões: Os meses de maiores picos polínicos foram setembro com 2.525 grãos/m3 de pólen de Mimosa scabrela, totalizando no ano 3.124 grãos/m3, sendo o tipo polínico de maior concentração no ano de 2007, seguido de Urticaceae com uma concentração no mês de outubro de 542 grãos/m3 e totalizando durante o ano 2.052 grãos/m3 e Cupressaceae que totalizou 655 grãos/m3 em julho e no ano 1.075 grãos/m3.

Objectives: To identify and quantify the pollen types in the atmosphere of Caxias do Sul and the seasonal oscillations of pollen grains during the year 2007 and to analyze the correlations between the meteorological parameters and the concentration of atmospheric pollen. Methods: To obtain the pollen grains, we used the suction volumetric sampler, Hirst type (Burkard model), placed on the roof of the Hospital Geral, at about 20m, because it is a place that does not show any obstacles that can block the air mass. Results: We obtained 14,436 pollen grains/m3 collected in the year of 2007. It was found a very differentiated monthly maximum concentration, one in spring, mainly due to the flowering of Euphorbiacea, Urticaceae, Poaceae, Myrtaceae e Carya and other in winter fundamentally due to the flowering of woody plants such as Mimosa scabrella, Cupressaceae, Pinaceae, Platanus and Melastomataceae. About the relations between the meteorological factors and the concentration of pollen released by plants, we can state that the temperature and the precipitation are the main responsible for the great quantitative changes of pollen grains. Conclusions: The month of the highest pollen peak was September with 2,525 grains/m3 of Mimosa scabrela pollen with a total in the year of 3,124 grains/m3, being the pollen type with the highest concentration in the year of 2007, followed by Urticaceae with a concentration in October of 542 grains/m3 and a total of 2,052 grains/m3 during the year and Cupressaceae in July with a total of 655 grains/m3 and in the year a total of 1,075 grains/m3.

Transporte de oócitos bovinos em meio de maturação por diferentes períodos de tempo sem controle da atmosfera gasosa / Transport of bovine oocytes in maturation medium for different periods of time whithout controlled gaseous atmosphere

Avaliou-se a viabilidade do transporte de oócitos em meio quimicamente definido, e analisou-se a necessidade da adição ou não de hormônios neste meio. Os oócitos do grupo-controle (0h) foram maturados por 24h em estufa de CO2, e os dos grupos experimentais foram transportados em incubadora portátil. No experimento I, as taxas de clivagem foram similares (P>0,05) para os grupos 0h (59,7 por cento), 3h (53,5 por cento) e 9h (48,8 por cento), e houve redução nos grupos 6h (46,1 por cento) e 12h (43,8 por cento). Essas taxas foram semelhantes entre os grupos 3h, 6h, 9h e 12h. A produção de blastocistos não foi diferente (P>0,05) para os grupos 0h (38,0 por cento), 3h (32,3 por cento), 6h (27,3 por cento) e 9h (24,8 por cento), e houve redução no grupo 12h (18,9 por cento). Essas taxas foram semelhantes entre os grupos 6h, 9h e 12h. No experimento II, não houve diferença (P>0,05) entre as taxas de clivagem para os grupos 0h (71,4 por cento), 3h (70,3 por cento), 6h (56,0 por cento) com hormônios, e os grupos 3h (64,8 por cento) e 6h (54,1 por cento) sem hormônios. A produção de blastocistos foi similar (P>0,05) para os grupos 0h (46,1 por cento), 3h com hormônios (45,8 por cento) e 3h sem hormônios (41,1 por cento), porém houve redução nos grupos 6h com hormônios (35,5 por cento) e 6h sem hormônios (33,5 por cento). Essas taxas foram semelhantes entre os grupos 3h sem hormônios e 6h com e sem hormônios. Estes resultados indicam que é possível otransporte de oócitos bovinos por um período de até nove horas, e que a adição de hormônios neste meio não influencia os índices de clivagem e de blastocistos.

The viability of the transport of the bovine oocytes was evaluated in chemically defined medium and the need for the addition or not of hormones in this medium was analyzed. The oocytes in the control group (0h) were matured for 24h in CO2 incubator, and in experimental groups they were transported in portable incubator. In experiment I, the cleavage rates were similar (P>0.05) to the groups 0h (59.7 percent), 3h (53.5 percent), and 9h (48.8 percent), but they decreased in groups 6h (46.1 percent) and 12h (43.8 percent), however, these rates were similar among the groups 3h, 6h, 9h, and 12h. The production of blastocysts was not different (P>0.05) for groups 0h (38.0 percent), 3h (32.3 percent), 6h (27.3 percent), and 9h (24.8 percent), but there was a reduction in the 12h group (18.9 percent). These rates were similar among the groups 6h, 9h and 12h. In experiment II, no significant difference (P>0.05) was observed among the rates of cleavage for the groups 0h (71.4 percent), 3h with (70.3 percent) and without hormones (64.8 percent), and 6h with (56.0 percent) and without hormones (54.1 percent). The production of blastocysts was similar (P>0.05) for groups 0h (46.1 percent) and 3h with (45.8 percent) and without hormones (41.1 percent), but decreased in groups 6h with (35.5 percent) and without hormones (33.5 percent). These rates were similar among the groups 3h without, 6h with and without hormones. These results indicate the possibility of the transport of bovine oocytes up to 9h, and the addition of hormones in this medium does not influence the rates of cleavage and blastocysts.

Características biogeoquímicas da interação atmosfera - criosfera na Antártica ocidental / Biogeochemical characteristics of the interaction atmosphere - cryosphere in the occidental Antarctic

Atualmente a comunidade científica discute as diferenças de padrões climáticos entre o leste e o oeste antártico. Enquanto de forma geral observa-se instabilidade no setor oeste, o clima da antártica oriental demonstra relativa estabilidade climática. Abordando este contexto, neste estudo analisamos dois testemunhos de gelo recente de duas regiões com características climáticas diferentes do continente Antártico. No Platô Detroit situado na Península Antártica (64o10'S/060o0'O), analisamos a variabilidde de Black Carbon (BC) ao longo de 20 metros de neve. O BC encontrado na Península Antártica apresentou baixas concentrações comparáveis as encontradas no gelo do Artico período pré-industrial. Nossos resultados sugerem que sua variabilidade corresponde à sazonalidade dos períodos de queimada nos continentes do Hemisfério Sul. No interior do continente Antártico, analisamos o particulado em geral por um processo de microanálise ao longo de um testemunho de 40 metros extraído em Mont Johns (79o55'S/094o23'O). Encontramos uma tendência negativa na deposição de poeira mineral (AISi) entre 1967 e 2007. Nossos resultados sugerem que esta tendência seja resultado de um crescente isolamento dos ventos ao redor da Antártica. Este aumento na intensidade dos ventos reflete por sua vez o resfriamento da alta atmosfera no centro antártico causado pela depleção da camada de ozônio na região. Adicionalmente, amostras de diferentes microambientes de Patriot Hills (80o18'S/081o21'O) foram coletadas de maneira asséptica para análise microbiológica. As amostras foram cultivadas em meio R2 e paralelamente o DNA total extraído foi sequenciado pela técnica de pirosequenciamento. Os resultados preliminares desta análise mostram grande riqueza de espécies dos mais variados grupos. Os resultados deste trabalho caracterizam três diferentes parâmetros relacionados a deposição atmosférica em duas áreas do continente antártico pouco exploradas e de grande interesse científico...

The antarctic ice cap stores paleoclimatological information within layers of snow and ice. Antarctic ice has revealed the higher resolution paleoclimactic database for the last 800 kyr. Atmospheric transport plays a fundamental role on the composition and sources of particulate matter found in the Antarctic ice. It has been related to several climatic processes that changes the quantity and quality of exogenous aerosols reaching Antarctica. Therefore, studies of the particulate matter deposits along the snow/ice layers may suggest changes on atmospheric transport patterns. This work, analyze two recent ice cores from two climatic distinct regions of the Antarctic continent. One retrieved from Detroit Plateau/Antarctic Peninsula (64o10'S/060o0'W), in which we have analyze Black Carbon (BC) deposition and variability along 20 meters of snow. BC found in the Antarctic Peninsula showed low concentrations (varing between 0,014 and 3,733ppb), comparable to the concentrations found on Arctic ice dated from before the industrial revolution period. Our results suggest that peaks of BC detected correspond, mostly, to biomass burning seasons in the South Hemosphere, not speficically from South America. The second one, of 40 m, was retrieved from Central-West Antarctica, Mont Johns (79o55'S/094o23'W), in which we analyzed the mineral dust abundance thought M.E.V. - E.D.X. technique. In this study we found negative trends in mineral dust (inferred from Fe, Ti and AISi) deposition between 1967 and 2007, in contrast to similar works in Sub-antarctic regions. We demonstrate that this trend is a consequence of the persistent "atmospheric isolation" that encloses the Central and East Antarctic regions due to the increasing winds around Antarctica within this period. It has been documented that westerlies intensification reflect the upper atmosphere cooling above Central Antarctica caused by the stratospherical ozone layer depletion. As part of the polar site...

Efeito da embalagem em atmosfera modificada sobre a validade comercial de filé de tilápia nilótica (Oreochromis niloticus) / Effect of modified atmosphere packaging on shelf life in nilotica tilapia fillet (Oreochromis niloticus)

O objetivo deste trabalho foi determinar o efeito da Embalagem em Atmosfera Modificada (EAM) sobre a validade comercialde filé fresco de tilápia nilótica estocada sob refrigeração de 5±1°C. Ao longo de 22 dias de estocagem, realizou-se acontagem de bactérias heterotróficas aeróbias mesófilas, análise de pH e análise sensorial de filés de tilápia submetidosaos tratamentos de ar atmosférico (100%), vácuo, 50/50 CO2/N2 e 100% CO2. Os resultados foram tratados estatisticamenteatravés de análise descritiva simples. As contagens bacterianas dos tratamentos 100% ar, vácuo e 50/50 CO2/N2 chegarama níveis >log 8,0 UFC/g nos dias 6, 16 e 12, respectivamente. No tratamento com EAM 100% CO2 as contagens mantiveramseentre log 2,8-4,1 UFC/g. O pH diminuiu com o tempo de estocagem em todos os tratamentos, estando sempre dentro dospadrões permitidos (d6,5). O atributo cor foi alterado significativamente pelos tratamentos com CO2, sendo que no vácuo acor manteve-se normal por mais tempo. Pôde-se concluir que a EAM com 100%CO2 apresentou melhores resultados noaumento de validade comercial de filés de tilápia estocados a 5°C, mantendo a contagem de mesófilos e valores de pH emníveis aceitáveis durante todo o período de estocagem de 22 dias.

The aim of the present work was to determine the effect of modified atmosphere packaging on shelf life in tilapia fillet stored at 5.0±1.0°C. The methodology consisted on four treatments of tilapia fillets: atmospheric air (100%), vacuum, 50/50 CO2/N2 and 100% CO2 , stored during 22 days under refrigeration at 5°C. The analyses were: mesophilic aerobic counting, pH and sensorial analysis. Statistical analysis was made by descriptive simple method. The results were: the bacterial counting of the treatments 100% air, vacuum and 50/50 CO2/N2 had arrived the levels >log 8.0 in days 6, 16 and 12, respectively. In tilapias filets with 100% CO2 the microbiological counting had been between log 2.8-4.1 UFC/g). The four treatments presented decreased pH with the time of stockage. The values were d”6.5, that represent acceptable standard. At sensorial analysis all CO2 treatment had significantly changed the fillet tilapia color. At vacuum the color was normal for longer time. The experiment permit conclude that 100%CO2 was the best ones treatment for longer the shelf life of tilapia fillet stored at 5.0°C, with microbiological counting and pH being in acceptable levels during all 22 days of storage.

El género Aspergillus en la atmósfera de La Habana (Cuba) / The Aspergillus genus in the atmosphere of La Habana, Cuba

Se ha realizado un estudio de la contaminación fúngica ambiental en la atmósfera de la ciudad de La Habana (Cuba), durante el período de lluvias de los años 2001 y 2002, utilizando un método volumétrico viable, que ha permitido conocer la concentración de unidades formadoras de colonias (ufc/m3) totales y caracterizar los géneros y especies más abundantes, en especial del género Aspergillus. Durante el año 2001 las concentraciones más elevadas de hongos se obtuvieron en agosto y septiembre y las más bajas en julio, mientras que en el año 2002 destacan los niveles de septiembre y octubre frente a los escasos niveles del mes de agosto. Al analizar la densidad relativa de los géneros identificados se observa que Aspergillus es el género más abundante en la atmósfera seguido de Penicillium y Cladosporium. Las especies más abundantes en el año 2001 y relativamente constantes en el tiempo fueron A. japonicus, A. niger y A. flavus, mientras en el año 2002, los más abundantes fueron: A. japonicus, A. fumigatus y A. niger, siendo A. niger el único constante en el tiempo.

A study on environmental fungal contamination in the atmosphere of the City of La Habana (Cuba), during the rainy period in 2001 and 2002 was carried out. A viable volumetric method was used, making it possible to ascertain the concentration of units comprising total colonies (ufc/m3), and to characterize the most abundant genera and species, especially Aspergillus. Throughout 2001, the highest concentrations of fungi were collected in August and September, and the lowest in July; while in 2002, the highest levels were in September and October, compared to the minimal levels for the month of August. On analyzing the relative density of the genera identified, it was found that the most abundant genus in the atmosphere was Aspergillus, followed by Penicillium and Cladosporium. The most abundant species and relatively constant over time in 2001 were A. japonicus, A. niger and A. flavus while in 2002 A. japonicus, A. fumigates and A. niger; this specie was the only constant in time.

Análisis cuantitativo y cualitativo de la aeromicota aislada de la Catedral de Santiago de Compostela (Galicia, España) / Quantitative and qualitative analysis of the airborne fungi isolated in the Cathedral of Santiago de Compostela (Galicia, Spain)

Mediante un estudio de la presencia de mitosporas fúngicas atmosféricas en el interior y exterior de la Catedral de Santiago de Compostela (España) durante un año, a través de un sistema de captación volumétrico viable, se identificaron 28 taxa, principalmente: Alternaria, Aspergillus, Cladosporium y Penicillium. Desde el punto de vista cuantitativo no existen diferencias significativas entre interior/exterior, y en ambos casos las concentraciones son ligeramente más elevadas en primavera-verano. Las especies más abundantes fueron: Penicillium purpurogenum Stoll, con un 94 por ciento en la atmósfera interna y un 82 por ciento en el exterior y Aspergillus fumigatus Fres., con un 65 por ciento y un 63 por ciento respectivamente.

A study was carried out on the atmosphericfungal content in the Cathedral of Santiago deCompostela (Spain) and its exterior during a year, usinga viable volumetric collecting system. A total of 28 taxawere identified, the most abundant of which were:Alternaria, Aspergillus, Cladosporium and Penicillium.In quantitative terms there were no significant indoor/outdoor differences, and the concentrations were slightlyhigher in Spring-Summer in both cases. The mostabundant species were Penicillium purpurogenum Stoll,with 94 percent in the indoor atmosphere and 82 percent outdoors,and Aspergillus fumigatus Fres., representing 65 percent inthe indoor and 63 percent outdoors.

study on relationship between the atmospheric quantity of heavy metals and PAHs in the city of Isfahan

Heavy metals are toxic and polycyclic aromatic hydrocarbons are known as toxic, carcinogenic and mutagenic compounds. To determine the concentration of PAHs and heavy metals in sample and the relationship between these two pollutants in the atmosphere of the city of Isfahan. In present study, air particulates were collected on glass fiber filters by using a high- volume air sampler. Flow rate and sampling period were 0.5m3/min and 12 hrs, respectively. Each filter was exactly cut into two equal pieces. One piece was digested with HNO3 and H2O2, and the second piece was extracted with DCM, using soxhlet method. The later was used for determination of PAHs. Determinations of heavy metals concentration were performed using a Perkin-Elmer atomic absorption spectrometer. The concentrations of PAHs were measured using a PU 4400 gas chromatograph equipped with a FID detector. The concentration of lead was higher than other metals [748.5 ng/m3] however; it was lower than the standard value [2000 ng/m3]. The extraction efficiency of PAHs with soxhlet method was 92-100 percent. The concentration of Benzo [ALPHA] pyrene, index of aromatic hydrocarbons, was 2.27 ng/m3. PAHs concentration in non-working days was lower than working days of a week. Correlation coefficient between PAHs and heavy metals was 0.9 [p<0.005]. The changing pattern of heavy metals and PAHs was closely similar. The concentrations of PAHs and heavy metals were determined in different samples. The relationship between the atmospheric concentrations of PAHs and heavy metals was investigated and an excellent agreement was found.

Frecuencia cardíaca máxima durante la prueba de esfuerzo en banda en 1853 sujetos sanos. Su relación con la edad y bajo las condiciones atmosféricas de la ciudad de México / Maximal hart rate during treadmill test in 1853 heathy individuals

Introducción. La relación de la frecuencia cardíaca (FC) con la edad durante la prueba de esfuerzo (PE) es dependiente de las condiciones de altura sobre el nivel del mar a la que se realiza. Objetivo. Definir el comportamiento de la frecuencia cardíaca máxima (FCM) alcanzada durante una PE en relación con la edad y la altura de la Ciudad de México. Método. Estudio observacional, no aleatorizado de una serie consecutiva de 1,853 sujetos sanos, sometidos a PE realizada con protocolo de Bruce clasificada como máxima, en el Departamento de Cardiología del Hospital Español de México. Resultados. La distribución por edades de la muestra correspondió al de una población normal, que fue dividida de acuerdo al sexo (67 por ciento masculinos y 33 por ciento femeninos), con edad media de 47.6 ñ 13.6 vs 49.6 ñ 13.7 años (p = 0.003), FCM alcanzada de 167.9 ñ 17.4 vs 160 ñ 18.2 latidos por minuto (p = 0.001), masculinos vs femeninos respectivamente. El 85.7 por ciento de entrenados-vs- 14.3 por ciento de no entrenados, en los cuales, la FCM fue del 169.1 ñ 16.4 vs 167.6 ñ 17.8 latidos por minuto, p > 0.05. Al correlacionar la FCM con la edad se obtuvo un coeficiente de correlación de 0.61 (Y = 204.37 + (-0.810*X, p = 0.001). Conclusiones. La FCM durante una PE en la Ciudad de México es menor a la reportada en la literatura, ésta, es dependiente de manera significativa con la edad del sujeto y no guarda relación con el grado de entrenamiento. Es menor en las mujeres de manera significativa, sin embargo se sostiene su relación con la edad.

Atmospheric mercury deposition over Brazil during the past 30.000 years

Atmospheric Hg deposition over Brazil is presented for the past 30,000 years as a tracer of the different natural and anthropogenic processes affecting the atmospheric environment of Brazil. During most of the prehistoric period, atmospheric deposition rates were rather constant with an average of about 2 mug m(-2) yr(-1). Peak deposition, ranging from 4 to 6 mug m2 y(-1), occurred at least during two periods between 3,300 and 3,600 BP and between 8,500 to 12,000 BP, and during the last glacial maximum (LGM), at about 18,000 years BP. These periods were characterized by drier, colder climates with high frequency of fores fires, as shoen by correlation with coal and pollen distribution data. During the colonial period Hg atmospheric deposition rates were much higher, about four times the prehistoric background and reached 6 to 8 mug m(-2) yr(-1). These increasing Hg deposition rates can only be explained by the large Hg emissions in South and Central America from Spanish silver mines, which emitted to the continent's environment about 200,000 tons of Hg from 1580 to 1820. During the present century, Hg deposition rates varied according to the region of the country. In the Amazon region, where gold mining is the major source of Hg emission to the atmosphere, deposition rates increased continuously during the last 40 years, reaching 8 to 10 mug m(-2) yr(-1). In the industrialized Southeast, Hg deposition was higher during the mild 1960s and 1970s, ranging from 80 to 130 mug m(-2) yr(-1), but decreased to 20 to 30 mug m(-2) yr(-1) in the 1990s, due to the enforcement of emission control policies. However, where Hg emissions are mostly from urban, nonpoint sources, such as along the high urbanized coastal area, Hg deposition, although smaller, increased steadily from the 1940s reaching a maximum at surface sediment layers of about 40.0 mug (-2) yr(-1). The results presented suggest Hg as a reliable tracer of natural (paleoclimatic changes) and anthropogenic (industrial and mining emissions) processes able to affect the atmosphere in Brazil.

El ENOS, el efecto invernadero, la capa de ozono y los inhaladores: una revisión / The \"fenómeno de El Niño\", the Greenhouse effect, the Ozone depletion and the inhalers: review

Se procede realizar una revisión acerca de los principales fenómenos climatológicos que afectan el planeta. El fenómeno de "El Niño", la Oscilación del Sur, el efecto invernadero, la depleción de la capa de Ozono y sus efectos en la salud. Los resultados para los pacientes de la actualidad y del futuro y para las generaciones que vendrán no son ni simples ni de poca importancia. Algunos de estos resultados han sido publicados y de otros de igual o mayor importacia ha sido prácticamente no mencionados. De los médicos no se puede esperar que se conviertan en expertos en ciencias atmosféricas o en políticas de ambientes, pero nuestro entrenamiento y experiencia continúa como vigilantes de la salud pública, nos califica, y tal vez de alguna forma nos responsabiliza, por la obligación de educar a nuestros pacientes y al público acerca de estos problemas de salud y cómo pueden prevenirse

Trace gas emissions from ecosystems of the Amazon basin

Tropical forests of Amazonia play a major role in controlling the composition of the earth's atmosphere. Natural ecosystems of Amazonia contribute significant portions to the global budgets of the greenhouse gases methane and nitrous oxide. Amazon forest vegetation contributes to regional atmospheric chemistry as an important source of reduced gases such as volatile organics and carbon monoxide. The forest soils produce nitric oxide. Recent trends in land use change have led to increases in the sources of nitrous oxide and methane. The ozone precursor nitric oxide is internally recycled under forest conditions while deforestation leads to larger net emissions. We have limited knowledge of biosphere-atmosphere exchange of trace gases in Amazonia. However, recent advances in instrumentation approaches and the evolution in the design of interdisciplinary field campaigns enhance the prospects for successful study of this area in earth system science.

La destrucción de la ozonósfera; ¿cuál es la real severidad e inminencia del peligro? / Ozone layer destruction: which is the severe problem and an imminent danger?

El problema del aumento estacional de irradiación UV debido a la destrucción del O3, en latitudes australes y ocasionalmente inferiores a 33ºS, es muy preocupante. Se debe directamente a la acción antrópica y tiene un riesgo potencial alto para toda la biósfera y el sistema global, a causa de la alta acumulación de CFC, gases con efecto invernadero. La ozonósfera estará afectada hasta los años 2.070 y 2.090, pudiendo la situación empeorar o ser controlada según se intervenga por parte de la comunidad mnudial organizada. El impacto y duración de los efectos dependerá de la consistencia de las decisiones en relación a los hechos y riesgos comprobados por científicos y ambientalistas, y la priorización secundaria de otros intereses. Los profesionales de la salud deben participar y promover el conocimiento del problema, y educar a sus pacientes. Los estados tienen la responsabilidad de preservar el medio, no sólo por ética ecológica y requerimiento básico para sustentar un proceso de desarrollo continuo, si no por razones de seguridad de sus habitantes y proteción de sus derechos fundamentales. Para ello, deben establecerse políticas permanentes sobre el uso y preservación del medio aeroespacial, entre otras. Las acciones deben involucrar tanto a autoridades como a científicos, organizaciones diversas y medios de comunicación; dentro de las instituciones, las de la Defensa Nacional tienen un rol público muy importante. La carga demográfica del planeta crece actualmente en 1 millón de habitantes cada 5 días y se habrá duplicado durante la primera etapa de sobre irradiación ultravioleta, sometiendo a una inmensa población al riesgo. La ozonósfera es un precioso bien de la vida, que la humanidad debe proteger por insustituible. Su destrucción afectaría a toda la biósfera, pero en forma más severa a los territorios más australes, como el de Chile. Es necesario aceptar, llamar la atención y crear conciencia sobre un riesgo silencioso pero real, evolutivo y amenazante, que existe por años y nos afecta hoy; y actuar eficientemente. Mañana, si fuese tarde, podríamos estar frente al primer desastre "natural" de origen tecnólógico puro en la historia del planeta