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About 30% of the Hungarian population has some type of allergy, 65% of them have pollen sensitivity, and at least 60% of this pollen sensitivity is caused by ragweed. The short (or common) ragweed (Ambrosia artemisiifolia = Ambrosia elatior) has the most aggressive pollen of all. Clinical investigations prove that its allergenic pollen is the main reason for the most massive, most serious and most long-lasting pollinosis. The air in the Carpathian Basin is the most polluted with ragweed pollen in Europe. The aim of the study is to analyse how ragweed pollen concentration is influenced by meteorological elements in a medium-sized city, Szeged, Southern Hungary. The data basis consists of daily ragweed pollen counts and averages of 11 meteorological parameters for the 5-year daily data set, between 1997 and 2001. The study considers some of the ragweed pollen characteristics for Szeged. Application of the Makra test indicates the same period for the highest pollen concentration as that established by the main pollination period. After performing factor analysis for the daily ragweed pollen counts and the 11 meteorological variables examined, four factors were retained that explain 84.4% of the total variance of the original 12 variables. Assessment of the daily pollen number was performed by multiple regression analysis and results based on deseasonalised and original data were compared.

A comparison of the structural orders of membranes of a mixed brain-cell population isolated from Cyprinus carpio L. acclimated to either summer (23-250C) or winter (50C) revealed a high degree of compensation (80%) for temperature, as assayed by electron spin resonance spectroscopy. The cells rapidly forget their thermal history and adjust the physical properties of the membranes when shifted to the other extreme of temperature either in vivo or in vitro. Phospholipids separated from both types of animals exhibit only around 10% compensation. Arachidonic and docosahexaenoic acids are the major polyunsaturated fatty acids in the brains, but the fatty acid composition of the brain total phospholipids does not vary with adaptation to temperature. Separation of phosphatidylcholines and phosphatidylethanolamines into molecular species revealed a 2-to 3-fold accumulation of 18:1/ 22:6, 18:1/20:4, and 18:1/18:1 species in the latter; 18:0/22:6 showed an opposite tendency. Molecular species composition of phosphatidylcholines did not vary with the temperature. The same trends of changes were seen with brains offreshwater fish from subtropical (Coda cada L.) or boreal (Acerina cernua) regions. It is concluded that the gross amount of docosahexaenoic acid (22:6) plays only a minor role in adjusting the membrane physical properties to temperature. Factors other than lipids might be involved in the adaptation processes. Due to their specific molecular architecture, molecules such as 18:1/22:6, 18:1/20:4, or 18:1/18:1 phosphatidylethanolamine might prevent the contraction of membranes in the cold and may provide an environment for some other components involved in the temperature regulation ofphysical properties of nerve cell membranes.Most poikilotherms respond to thermal changes by adapting the physical properties of their membranes to the new situation to preserve the functional and structural integrity of these structures, a phenomenon that Sinensky (1) termed "homeoviscous adaptation." The homeoviscous efficacy, the extent to which the cells compensate for temperature changes, varies among the tissues and membranes (2, 3). Adjustment of the physicochemical properties of the membranes to the temperature is expected to be rapid and reversible to ensure proper functioning under fluctuating thermal conditions in fish. Wodtke and Cossins (4) have shown that the fluidity of the mitochondria in fish liver follows changes in the environmental temperature. It has also been demonstrated that the plasma membrane of carp erythrocyte rapidly adjusts to temperature under both in vivo and in vitro conditions (5, 6). The functions of neural tissue are highly dependent on membrane processes. Adaptation of the physical state of the synaptic vesicles in fish brain (2, 7), of the synaptic vesicles, mitochondria, and myelin fractions of an air-breathing, subtropical fish, Channa punctatus (8), and of the synaptosomal and myelin fraction of carp brain (9) has been described. Changes in environmental temperature have been shown to ca...

This paper discusses a subjectively defined system of air mass types, the 13 Péczely's large-scale weather situations over the Carpathian Basin in relation to the detected airborne pollen grain concentrations. Based on the ECMWF (European Centre for Medium-Range Weather Forecasts) sea-level pressure data set, daily sea-level pressure fields analyzed at 00:00 UTC were prepared for each Péczely's weather types in order to relate the sea-level pressure patterns with the average pollen levels in Szeged. The data basis for this study comprises daily values of 12 meteorological parameters and daily average pollen concentrations for 24 species in a 5-year period (1997)(1998)(1999)(2000)(2001). It was found that Péczely's anticyclonic ridge types 2 and 11 as well as cyclonic types 4 and 7 are favourable for pollen production and dispersal unlike the cyclonic types 3 and 13. Hence, the Péczely's large-scale weather situations cannot alone be considered as an overall system in predicting pollen concentrations.

This paper discusses the characteristic air mass types over the Carpathian Basin in relation to plant pollen levels over annual pollination periods. Based on the European Centre for Medium-Range Weather Forecasts dataset, daily sea-level pressure fields analysed at 00 UTC were prepared for each air mass type (cluster) in order to relate sea-level pressure patterns to pollen levels in Szeged, Hungary. The database comprises daily values of 12 meteorological parameters and daily pollen concentrations of 24 species for their pollination periods from 1997 to 2001. Characteristic air mass types were objectively defined via factor analysis and cluster analysis. According to the results, nine air mass types (clusters) were detected for pollination periods of the year corresponding to pollen levels that appear with higher concentration when irradiance is moderate while wind speed is moderate or high. This is the case when an anticyclone prevails in the region west of the Carpathian Basin and when Hungary is under the influence of zonal currents (wind speed is high). The sea level pressure systems associated with low pollen concentrations are mostly similar to those connected to higher pollen concentrations, and arise when wind speed is low or moderate. Low pollen levels occur when an anticyclone prevails in the region west of the Carpathian Basin, as well as when an anticyclone covers the region with Hungary at its centre. Hence, anticyclonic or anticyclonic ridge weather situations seem to be relevant in classifying pollen levels.