Turbulent vertical fluxes and air quality measured in urban air in Helsinki

There is a growing need to understand the exchange processes of momentum, heat and mass between an urban surface and the atmosphere as they affect our quality of life. Understanding the source/sink strengths as well as the mixing mechanisms of air pollutants is particularly important due to their effects on human health and climate. This work aims to improve our understanding of these surface-atmosphere interactions based on the analysis of measurements carried out in Helsinki, Finland. The vertical exchange of momentum, heat, carbon dioxide (CO2) and aerosol particle number was measured with the eddy covariance technique at the urban measurement station SMEAR III, where the concentrations of ultrafine, accumulation mode and coarse particle numbers, nitrogen oxides (NOx), carbon monoxide (CO), ozone (O3) and sulphur dioxide (SO2) were also measured. These measurements were carried out over varying measurement periods between 2004 and 2008. In addition, black carbon mass concentration was measured at the Helsinki Metropolitan Area Council site during three campaigns in 1996-2005. Thus, the analyzed dataset covered far, the most comprehensive long-term measurements of turbulent fluxes reported in the literature from urban areas. Moreover, simultaneously measured urban air pollution concentrations and turbulent fluxes were examined for the first time. The complex measurement surrounding enabled us to study the effect of different urban covers on the exchange processes from a single point of measurement. The sensible and latent heat fluxes closely followed the intensity of solar radiation, and the sensible heat flux always exceeded the latent heat flux due to anthropogenic heat emissions and the conversion of solar radiation to direct heat in urban structures. This urban heat island effect was most evident during winter nights. The effect of land use cover was seen as increased sensible heat fluxes in more built-up areas than in areas with high vegetation cover. Both aerosol particle and CO2 exchanges were largely affected by road traffic, and the highest diurnal fluxes reached 109 m-2 s-1 and 20 µmol m-2 s-1, respectively, in the direction of the road. Local road traffic had the greatest effect on ultrafine particle concentrations, whereas meteorological variables were more important for accumulation mode and coarse particle concentrations. The measurement surroundings of the SMEAR III station served as a source for both particles and CO2, except in summer, when the vegetation uptake of CO2 exceeded the anthropogenic sources in the vegetation sector in daytime, and we observed a downward median flux of 8 µmol m-2 s-1. This work improved our understanding of the interactions between an urban surface and the atmosphere in a city located at high latitudes in a semi-continental climate. The results can be utilised in urban planning, as the fraction of vegetation cover and vehicular activity were found to be the major environmental drivers affecting most of the exchange processes. However, in order to understand these exchange and mixing processes on a city scale, more measurements above various urban surfaces accompanied by numerical modelling are required.

How Kings are Made, How Kingship Changes : A Study of Ritual and Ritual Change in Pre-Colonial Owamboland, Namibia

This study discusses the legitimacy basis of political power and its changes in historical African societies. It starts from Luc de Heusch s tenet that political power required a legitimacy basis of a spiritual kind, often formulated as sacred kingship. In ancient and pre-literate societies such kings were held to be responsible for the fertility of man, land and cattle. The king was a paradoxical figure, symbolising society, but standing above it, while simultaneously being its victim by being ritually killed at old age. This was also how Owambo sacred kings were conceived. De Heusch suggested that African kings derived their power over fertility from having been made sacred monsters in the rituals of installation. With the example of Owambo kingship, this study argues that the transgressive and monstrous aspect is only one of several dimension of a king s sacredness and brings out the nurturing and symbolically female aspect, identified but not analysed further by de Heusch. In the Owambo kingly installation a king-elect was made sacred, and part of it was that a link was ritually created to the early owners of the land. Their consent made it possible for the king to promote fertility and to appropriate power emblems needed for ruling. In the kingdom of Ondonga the early owners of the land were the spirits of early Bushman inhabitants and those of an early kingly clan, both neglected in public memory. The sacred dimension of kingship was further augmented when kings manipulated and appropriated rain rituals and initiation rituals, both of which were related to fertility. The study argues that even though there were aspects of the sacred monster in Owambo kingship, its manifestation was, in part, a distortion of the reciprocal aspect of kingship that was expressed in the homage paid to various ancestor spirits. A change in succession practices from ritual regicide to political assassination took place concomitant with the introduction of firearms, and this broke the sacrificial aspect of sacred kingship paving the way for a more predatory form of kingship while the sacred status of the king was retained.

Future chemistry teachers use of knowledge dimensions and high-order cognitive skills in pre-laboratory concept maps

This poster describes a pilot case study, which aim is to study how future chemistry teachers use knowledge dimensions and high-order cognitive skills (HOCS) in their pre-laboratory concept maps to support chemistry laboratory work. The research data consisted of 168 pre-laboratory concept maps that 29 students constructed as a part of their chemistry laboratory studies. Concept maps were analyzed by using a theory based content analysis through Anderson & Krathwohls' learning taxonomy (2001). This study implicates that novice concept mapper students use all knowledge dimensions and applying, analyzing and evaluating HOCS to support the pre-laboratory work.

Pre-eclampsia : The role of soluble VEGF receptor-1 and related anti-angiogenic factors beyond

Pre-eclampsia is a pregnancy complication that affects about 5% of all pregnancies. It is known to be associated with alterations in angiogenesis -related factors, such as vascular endothelial growth factor (VEGF). An excess of antiangiogenic substances, especially the soluble receptor-1 of VEGF (sVEGFR-1), has been observed in maternal circulation after the onset of the disease, probably reflecting their increased placental production. Smoking reduces circulating concentrations of sVEGFR-1 in non-pregnant women, and in pregnant women it reduces the risk of pre-eclampsia. Soluble VEGFR-1 acts as a natural antagonist of VEGF and placental growth factor (PlGF) in human circulation, holding a promise for potential therapeutic use. In fact, it has been used as a model to generate a fusion protein, VEGF Trap , which has been found effective in anti-angiogenic treatment of certain tumors and ocular diseases. In the present study, we evaluated the potential use of maternal serum sVEGFR-1, Angiopoietin-2 (Ang-2) and endostatin, three central anti-angiogenic markers, in early prediction of subsequent pre-eclampsia. We also studied whether smoking affects circulating sVEGFR-1 concentrations in pregnant women or their first trimester placental secretion and expression in vitro. Last, in order to allow future discussion on the potential therapy based on sVEGFR-1, we determined the biological half-life of endogenous sVEGFR-1 in human circulation, and measured the concomitant changes in free VEGF concentrations. Blood or placental samples were collected from a total of 268 pregnant women between the years 2001 2007 in Helsinki University Central Hospital for the purposes above. The biomarkers were measured using commercially available enzyme-linked immunosorbent assays (ELISA). For the analyses of sVEGFR-1, Ang-2 and endostatin, a total of 3 240 pregnant women in the Helsinki area were admitted to blood sample collection during two routine ultrasoundscreening visits at 13.7 ± 0.5 (mean ± SD) and 19.2 ± 0.6 weeks of gestation. Of them, 49 women later developing pre-eclampsia were included in the study. Their disease was further classified as mild in 29 and severe in 20 patients. Isolated early-onset intrauterine growth retardation (IUGR) was diagnosed in 16 women with otherwise normal medical histories and uncomplicated pregnancies. Fifty-nine women remaining normotensive, non-proteinuric and finally giving birth to normal-weight infants were picked to serve as the control population of the study. Maternal serum concentrations of Ang-2, endostatin and sVEGFR-1, were increased already at 16 20 weeks of pregnancy, about 13 weeks before the clinical manifestation of preeclampsia. In addition, these biomarkers could be used to identify women at risk with a moderate precision. However, larger patient series are needed to determine whether these markers could be applied for clinical use to predict preeclampsia. Intrauterine growth retardation (IUGR), especially if noted at early stages of pregnancy and not secondary to any other pregnancy complication, has been suggested to be a form of preeclampsia compromising only the placental sufficiency and the fetus, but not affecting the maternal endothelium. In fact, IUGR and preeclampsia have been proposed to share a common vascular etiology in which factors regulating early placental angiogenesis are likely to play a central role. Thus, these factors have been suggested to be involved in the pathogenesis of IUGR. However, circulating sVEGFR-1, Ang-2 and endostatin concentrations were unaffected by subsequent IUGR at early second trimester. Furthermore, smoking was not associated with alterations in maternal circulating sVEGFR-1 or its placental production. The elimination of endogenous sVEGFR-1 after pregnancy was calculated from serial samples of eight pregnant women undergoing elective Caesarean section. As typical for proteins in human compartments, the elimination of sVEGFR-1 was biphasic, containing a rapid halflife of 3.4 h and a slow one of 29 h. The decline in sVEGFR-1 concentrations after mid-trimester legal termination of pregnancy was accompanied with a simultaneous increase in the serum levels of free VEGF so that within a few days after pregnancy VEGF dominated in the maternal circulation. Our study provides novel information on the kinetics of endogenous sVEGFR-1, which serves as a potential tool in the development of new strategies against diseases associated with angiogenic imbalance and alterations in VEGF signaling.

Pre-harvest measurement of pine stands for sawing production planning.

To enhance the utilization of the wood, the sawmills are forced to place more emphasis on planning to master the whole production chain from the forest to the end product. One significant obstacle to integrating the forest-sawmill-market production chain is the lack of appropriate information about forest stands. Since the wood procurement point of view in forest planning systems has been almost totally disregarded there has been a great need to develop an easy and efficient pre-harvest measurement method, allowing separate measurement of stands prior to harvesting. The main purpose of this study was to develop a measurement method for pine stands which forest managers could use in describing the properties of the standing trees for sawing production planning. Study materials were collected from ten Scots pine stands (Pinus sylvestris) located in North Häme and South Pohjanmaa, in southern Finland. The data comprise test sawing data on 314 pine stems, dbh and height measures of all trees and measures of the quality parameters of pine sawlog stems in all ten study stands as well as the locations of all trees in six stands. The study was divided into four sub-studies which deal with pine quality prediction, construction of diameter and dead branch height distributions, sampling designs and applying height and crown height models. The final proposal for the pre-harvest measurement method is a synthesis of the individual sub-studies. Quality analysis resulted in choosing dbh, distance from stump height to the first dead branch (dead branch height), crown height and tree height as the most appropriate quality characteristics of Scots pine. Dbh and dead branch height are measured from each pine sample tree while height and crown height are derived from dbh measures by aid of mixed height and crown height models. Pine and spruce diameter distribution as well as dead branch height distribution are most effectively predicted by the kernel function. Roughly 25 sample trees seems to be appropriate in pure pine stands. In mixed stands the number of sample trees needs to be increased in proportion to the intensity of pines in order to attain the same level of accuracy.

Microbiological characterisation of soils : Evaluation of some critical steps in data collection and experimental design

The study of soil microbiota and their activities is central to the understanding of many ecosystem processes such as decomposition and nutrient cycling. The collection of microbiological data from soils generally involves several sequential steps of sampling, pretreatment and laboratory measurements. The reliability of results is dependent on reliable methods in every step. The aim of this thesis was to critically evaluate some central methods and procedures used in soil microbiological studies in order to increase our understanding of the factors that affect the measurement results and to provide guidance and new approaches for the design of experiments. The thesis focuses on four major themes: 1) soil microbiological heterogeneity and sampling, 2) storage of soil samples, 3) DNA extraction from soil, and 4) quantification of specific microbial groups by the most-probable-number (MPN) procedure. Soil heterogeneity and sampling are discussed as a single theme because knowledge on spatial (horizontal and vertical) and temporal variation is crucial when designing sampling procedures. Comparison of adjacent forest, meadow and cropped field plots showed that land use has a strong impact on the degree of horizontal variation of soil enzyme activities and bacterial community structure. However, regardless of the land use, the variation of microbiological characteristics appeared not to have predictable spatial structure at 0.5-10 m. Temporal and soil depth-related patterns were studied in relation to plant growth in cropped soil. The results showed that most enzyme activities and microbial biomass have a clear decreasing trend in the top 40 cm soil profile and a temporal pattern during the growing season. A new procedure for sampling of soil microbiological characteristics based on stratified sampling and pre-characterisation of samples was developed. A practical example demonstrated the potential of the new procedure to reduce the analysis efforts involved in laborious microbiological measurements without loss of precision. The investigation of storage of soil samples revealed that freezing (-20 °C) of small sample aliquots retains the activity of hydrolytic enzymes and the structure of the bacterial community in different soil matrices relatively well whereas air-drying cannot be recommended as a storage method for soil microbiological properties due to large reductions in activity. Freezing below -70 °C was the preferred method of storage for samples with high organic matter content. Comparison of different direct DNA extraction methods showed that the cell lysis treatment has a strong impact on the molecular size of DNA obtained and on the bacterial community structure detected. An improved MPN method for the enumeration of soil naphthalene degraders was introduced as an alternative to more complex MPN protocols or the DNA-based quantification approach. The main advantage of the new method is the simple protocol and the possibility to analyse a large number of samples and replicates simultaneously.