Search results for "Seasons"
showing 10 items of 361 documents
The role ofSphagnummosses in the methane cycling of a boreal mire
2010
Peatlands are a major natural source of atmospheric methane (CH4). Emissions from Sphagnum-dominated mires are lower than those measured from other mire types. This observation may partly be due to methanotrophic (i.e., methane-consuming) bacteria associated with Sphagnum. Twenty-three of the 41 Sphagnum species in Finland can be found in the peatland at Lakkasuo. To better understand the Sphagnum-methanotroph system, we tested the following hypotheses: (1) all these Sphagnum species support methanotrophic bacteria; (2) water level is the key environmental determinant for differences in methanotrophy across habitats; (3) under dry conditions, Sphagnum species will not host methanotrophic ba…
The association between respiratory tract infection incidence and localised meningitis epidemics: an analysis of high-resolution surveillance data fr…
2017
AbstractMeningococcal meningitis epidemics in the African meningitis belt consist of localised meningitis epidemics (LME) that reach attack proportions of 1% within a few weeks. A meningococcal serogroup A conjugate vaccine was introduced in meningitis belt countries from 2010 on, but LME due to other serogroups continue to occur. The mechanisms underlying LME are poorly understood, but an association with respiratory pathogens has been hypothesised. We analysed national routine surveillance data in high spatial resolution (health centre level) from 13 districts in Burkina Faso, 2004–2014. We defined LME as a weekly incidence rate of suspected meningitis ≥75 per 100,000 during ≥2 weeks; and…
Strategies to improve vitamin D status in northern European children: exploring the merits of vitamin D fortification and supplementation.
2006
Adequacy of vitamin D in children in Europe has been the focus of a number of investigations. The results of measuring serum levels of 25-hydroxyvitamin D show high prevalence of vitamin D deficiency during the winter with lower prevalence during the summer. National policies on food fortification or individual supplementation with vitamin D have been recently revisited by the individual countries and the European Union as a whole. Optiford is a project managed by a coalition of scientists formed to optimize vitamin D fortification in the northern European Countries, was given the task to decide if food fortification with vitamin D is feasible and to provide a scientific basis for setting t…
Pentachlorophenol accumulation in the freshwater mussels Anodonta anatina and Pseudanodonta complanata, and some physiological consequences of labora…
1995
Freshwater mussels Anodanta anatina and Pseudanodonta complanata were exposed to (14C)-pentachlorophenol. The wet weight based bioconcentration factor (BCF = activity in animal per activity in water) at steady state varied from 80 to 120 for A. anatina and from 61 to 85 for P. complanata. The species did not differ significantly in their wet weight or lipid based BCFs but dry weight based values were significantly higher (40-50%) for A. anatina. The soft tissue dry weight and dry weight based condition index of A. anatina (Cl4 = soft tissue dry weight per shell length) differed significantly between natural mussel populations. In animals kept from 4 to 8 months in laboratory conditions, the…
Seasonal gene expression kinetics between diapause phases in Drosophila virilis group species and overwintering differences between diapausing and no…
2015
AbstractMost northern insect species experience a period of developmental arrest, diapause, which enables them to survive over the winter and postpone reproduction until favorable conditions. We studied the timing of reproductive diapause and its long-term effects on the cold tolerance of Drosophila montana, D. littoralis and D. ezoana females in seasonally varying environmental conditions. At the same time we traced expression levels of 219 genes in D. montana using a custom-made microarray. We show that the seasonal switch to reproductive diapause occurs over a short time period and that overwintering in reproductive diapause has long-lasting effects on cold tolerance. Some genes, such as…
The activity of glutathione S-transferase in hepatopancreas of Procambarus clarkii: Seasonal variations and the influence of environmental pollutants
1991
Abstract 1. 1The glutathione S -transferase activity in hepatopancreas of the American red crayfish Procambarus clarkii after 15 days' acclimatization in tap water aquaria was measured in specimens collected monthly for a whole year, and shows seasonal variation. 2. 2. Previous data on the environmental pollution of Lake Albufera suggest a possible correlation with the activity tested in the different seasons of the year considering the results of non-acclimatized animals.
Toward the definition of a carbon budget model: seasonal variation and temperature effect on respiration rate of vegetative and reproductive organs o…
2009
Summary This study, as a preliminary step toward the definition of a carbon budget model for pistachio trees (Pistacia vera L.), aimed at estimating and evaluating the dynamics of respiration of vegetative and reproductive organs of pistachio tree. Trials were performed in 2005 in a commercial orchard located in Sicily (370 m a.s.l.) on five bearing 20-year-old pistachio trees of cv. Bianca grafted onto Pistachio terebinthus L. Growth analyses and respiration measurements were done on vegetative (leaf) and reproductive (infructescence) organs during the entire growing season (April–September) at biweekly intervals. Results suggested that the respiration rates of pistachio reproductive and v…
Urban air pollution and emergency room admissions for respiratory symptoms: a case-crossover study in Palermo, Italy
2011
Abstract Background Air pollution from vehicular traffic has been associated with respiratory diseases. In Palermo, the largest metropolitan area in Sicily, urban air pollution is mainly addressed to traffic-related pollution because of lack of industrial settlements, and the presence of a temperate climate that contribute to the limited use of domestic heating plants. This study aimed to investigate the association between traffic-related air pollution and emergency room admissions for acute respiratory symptoms. Methods From January 2004 through December 2007, air pollutant concentrations and emergency room visits were collected for a case-crossover study conducted in Palermo, Sicily. Ris…
Effect of deicing salts on urban soils and health status of roadside trees in the Opole region.
2004
This article reports on a study whose aim was to evaluate the impact of snow removal salts on urban soil properties and the health of roadside trees. The evaluation was done by chemical analyses of soil samples and plant matter combined with toxicity testing, performed with a Protoxkit F, a protozoan microbiotest. Samples were collected at 45 locations on three main roads in the town of Opole (Poland). The roads differed in the snow removal technology and amount of chemical substances (mostly NaCI) used on them during the winter. The study showed that when soil was exposed to a high level of NaCI, it tended to be more alkaline and also exhibited increased content of Na + and Cl - . The toxi…
Soil mutagens are airborne mutagens: variation of mutagenic activities induced in Salmonella typhimurium TA 98 and TA 100 by organic extracts of agri…
2000
As our hypothesis was that soil mutagens are airborne mutagens, possibly modified by soil microorganisms, we checked solvent extracts from agricultural and forest soils collected during late summer in the environment of Mainz, a region highly charged by anthropogenic air pollution, or near Bayreuth, a rural low charged region of Germany, or in a remote region of western Corsica without anthropogenic air pollution for the presence of mutagenicity in Salmonella typhimurium. Levels of mutagenic activities were quantified by calculation of revertants/g from the initial slope of dose-response curves applying tester strains S. typhimurium TA 98 and TA 100 in the absence and presence of an activat…