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Atmospheric Pollution (atmospheric + pollution)
Selected AbstractsHuman birth seasonality and sunshineAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2010David R. CummingsArticle first published online: 20 OCT 200 The environmental light intensity/photoperiod (ELI/PP) hypothesis proposes that the seasonality of human births is primarily associated with seasonal changes in ambient atmospheric luminosity or ELI. This study tests for the presence of increased ELI during the 1 or 2-month period preceding the conceptual month. Monthly birth data for Helsinki, Finland; Kiev, Ukraine; Hanoi, Vietnam; Matlab, Bangladesh; Nashville, Tennessee; Los Angeles, California; Dallas, Texas; Denver, Colorado and Pretoria, South Africa, are correlated (Pearsonian r) to corresponding monthly meteorological data. With the exception of Matlab, birth data are adjusted for conception date, 31-day months, leap years and monthly deviation from an annual mean. Meteorological data are adjusted for a 1,2-month exposure to ELI before conception. From these correlations, Helsinki r = 0.82, Kiev r = 0.80, Hanoi r = 0.93, Matlab r = 0.91, Nashville r = 0.84, Los Angeles r = 0.71, Dallas r = 0.86, Denver r = 0.53, and Pretoria r = ,82. Weakness and strengths of the ELI/PP hypothesis are reviewed using the criteria developed by AB Hill. Substituting meteorological variables for ELI may be a weakness, whereas the specificity of ELI/PP predictions may be a strength. Increased periods of ELI precede increased periods of conceptions. Increased ELI may influence seasonality for chimpanzee, baboon, and humans. Atmospheric pollution may alter the onset of seasonality. Increased ELI may be the initial, but not the singular variable to affect seasonality. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source] Instability of the structure and allergenic protein content in Arizona cypress pollenALLERGY, Issue 12 2009Y. Shahali Background:, The allergenic characteristics of pollen and their levels of expression may vary depending on the plant species, the degree of maturation and the influence of environmental factors such as climate and atmospheric pollution. The objective of this survey was the comparison of the structure and allergenic protein content in Arizona cypress (Cupressus arizonica, CA) pollen collected just after microsporangia dehiscence and 2 weeks later in urban areas. Methods:, The morphology and structure of pollen were examined by scanning electron microscopy. Pollen protein content was quantitatively and qualitatively investigated by Bradford protein assay, SDS-PAGE and densitometric analysis respectively. Fifteen allergic subjects, according to their clinical history of seasonal rhino-conjunctivitis and bronchial asthma have been selected for skin prick testing and ImmunoCap using CA standard allergen and for immunoblotting using extracts of CA mature pollen collected from Tehran. Results:, After 2 weeks, numerous cracks and collapses appeared in pollen surfaces. Western blotting performed by using extracts of pollen collected from Tehran, revealed that sera-specific immunoglobulin E of all allergic subjects reacted to a 35 kDa protein. The presence of this new major allergen and the decrease of Cup a 1 provide reliable explications about the low efficiency of standard commercial allergens in the diagnosis of the CA pollen allergy in Tehran. Conclusion:, The instability of the pollen structure and protein content affects CA pollen allergenic properties. This study also suggests that to optimize CA standard allergen preparations, the eventual variability of pollen allergenic components have to be considered for each region. [source] Mesoscale simulations of atmospheric flow and tracer transport in Phoenix, ArizonaMETEOROLOGICAL APPLICATIONS, Issue 3 2006Ge Wang Abstract Large urban centres located within confining rugged or complex terrain can frequently experience episodes of high concentrations of lower atmospheric pollution. Metropolitan Phoenix, Arizona (United States), is a good example, as the general population is occasionally subjected to high levels of lower atmospheric ozone, carbon monoxide and suspended particulate matter. As a result of dramatic but continuous increase in population, the accompanying environmental stresses and the local atmospheric circulation that dominates the background flow, an accurate simulation of the mesoscale pollutant transport across Phoenix and similar urban areas is becoming increasingly important. This is particularly the case in an airshed, such as that of Phoenix, where the local atmospheric circulation is complicated by the complex terrain of the area. Within the study presented here, a three-dimensional time-dependent mesoscale meteorological model (HOTMAC) is employed for simulation of lower-atmospheric flow in Phoenix, for both winter and summer case-study periods in 1998. The specific purpose of the work is to test the model's ability to replicate the atmospheric flow based on the actual observations of the lower-atmospheric wind profile and known physical principles. While a reasonable general agreement is found between the model-produced flow and the observed one, the simulation of near-surface wind direction produces a much less accurate representation of actual conditions, as does the simulation of wind speed over 1,000 metres above the surface. Using the wind and turbulence output from the mesoscale model, likely particle plume trajectories are simulated for the case-study periods using a puff dispersion model (RAPTAD). Overall, the results provide encouragement for the efforts towards accurately simulating the mesoscale transport of lower-atmospheric pollutants in environments of complex terrain. Copyright © 2006 John Wiley & Sons, Ltd. [source] Physiological Responses of Forest Trees to Heat and DroughtPLANT BIOLOGY, Issue 5 2006H. Rennenberg Abstract: The heat wave of summer 2003 was the largest and the most persistent ever experienced in Central Europe and has fuelled concern about the effects of climate change on European ecosystems. Since forests constitute the most important European ecosystems, in this review article we assess current knowledge on the effects of heat and drought on key metabolic processes for growth and productivity of forest trees. In particular, the general consequences of heat and drought on (1) photosynthesis and respiration at the cellular and community level, and (2) on nutrient uptake, partitioning and competition for nutrients are summarized. The latter are a major sink for photosynthetic energy and, therefore, are indirectly but strongly connected to the performance of photosynthesis. In addition, the interaction of heat and drought with stress compensation mechanisms and emission of biogenic volatile organic compounds (BVOC) are discussed, since these processes are directly connected to carbon metabolism. Effects on the emission of BVOC are also included because they constitute an important feedback mechanism on ozone formation and, thus, on atmospheric pollution. As far as available, data collected during the 2003 heat wave are included and discussed. [source] Investigation by solid-phase microextraction and gas chromatography/mass spectrometry of secondary metabolites in lichens deposited on stone monumentsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2003Francesco De Angelis Lichens are ubiquitous organisms formed by symbiotic associations of fungal hyphas and algae that also grow under often extreme environmental conditions. They produce secondary metabolites, the so-called lichen substances, whose structural characterization can give an important contribution to lichen taxonomy. Lichens are also widely employed as biomonitors of atmospheric pollution; being epiphyte organisms they tend, in fact, to accumulate exogenous compounds. Moreover, it could be questioned if the environmental stress alters their secondary metabolites production. Therefore, a new strategy for the analysis of the organic substances absorbed or metabolized by lichens has been developed. This method exploits the dry solid-phase microextraction (SPME) headspace technique coupled with gas chromatography/mass spectrometry (GC/MS). Lichens coating the stone surfaces of monuments, located in small towns between high mountains and far away from urban environments, have been investigated. In the field of cultural heritage, this study can contribute to the knowledge of the state of conservation of outdoor exposed historical monuments. Copyright © 2003 John Wiley & Sons, Ltd. [source] Protozoan population and fermentation parameters of rumen contents of sheep from heavy metal contaminated areaTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2005Z. VÁRADYOVÁ The rumen contents from Slovak Merino sheep (12 months of age) were used for in vitro study on the influence of area contaminated by heavy metals on rumen fermentation and protozoan activity. Sheep were browsing in the contaminated area of Kal'ava village (Slovakia) and were exposed to 1-year intake of heavy metals. The area of Kal'ava is contaminated by atmospheric pollution from the non-ferrous metal works at Krompachy (Slovakia). Based on the levels of mercury (4.8 mg'kg), copper (232.9 mg/kg), cadmium (1.2 mg/kg), lead (92.5 mg/kg) and arsenic (74.6 mg/1) the soil was categorized as profusely contaminated. Grass contamination was below the toxic limits. In the tested materials, copper was present at the highest levels followed by lead and arsenic. Meadow hay was used as a tested substrate of fermentation activity; it was incubated with buffered rumen fluid for 24 h. The significantly decreased values of fermentation parameters (total gas, methane, total VFA, acetate) were associated with a reduced total concentration of protozoans. Significant decrease was detected in the total rumen ciliate population and population of c. No significant differences were observed in the concentration of Dasytricha ruminantium and Ophryoscolex c. tricoronatus. The study was supported by funds from Grant Agency for Science of the Slovak Academy of Sciences (2/3058/23, 2/3064/23) and funds from APVT grant (51012602). [source] Determinants of Lichen Diversity in a Rain Forest UnderstoryBIOTROPICA, Issue 4 2007L. A. Dyer ABSTRACT Change in lichen diversity is often used as a bioindicator to estimate effects of atmospheric pollution, but natural variation in lichen cover and species richness can be very high. We examined the top-down effects of spore-consuming ants and the bottom-up effects of nutrient and light availability on lichen diversity associated with the leaf surface of the rain forest understory plant, Piper cenocladum. Plots containing P. cenocladum were randomly assigned to treatments in factorial experiments that included high and low light levels, nutrient enrichment, and presence and absence of the ant mutualist, Pheidole bicornis. At the conclusion of the experiments, plants were harvested and size of leaves, secondary metabolite content (amides), epiphyll cover, and the species richness of the lichens (which comprised 85% of the epiphyll community) were quantified. Epiphyll cover (mosses, liverworts, and lichens) was greater on plants that had ant-mutualists and balanced resources. Lichen species richness was greater for plants with balanced resources, particularly for those with high light availability. Relationships between toxins and lichen cover and richness were weak and unclear. In this system, natural sources of variation were reliable determinants of lichen diversity and both biotic and abiotic influences were important. [source] | ||||||||||