Developing ozone critical levels for multi-species canopies of Mediterranean annual pastures.

Ozone (O3) critical levels (CLe) are still poorly developed for herbaceous vegetation. They are currently based on single species responses which do not reflect the multi-species nature of semi-natural vegetation communities. Also, the potential effects of other factors like the nitrogen (N) input are not considered in their derivation, making their use uncertain under natural conditions. Exposure- and dose-response relationships were derived from two open-top chamber experiments exposing a mixture of 6 representative annual Mediterranean pasture species growing in natural soil to 4 O3 fumigation levels and 3 N inputs. The Deposition of O3 and Stomatal Exchange model (DO3SE) was modified to account for the multi-species nature of the canopy following a big-leaf approach. This new approach was used for estimating a multi-species phytotoxic O3 dose (PODy-MS). Response relationships were derived based on O3 exposure (AOT40) and flux (PODy-MS) indices. The treatment effects were similar in the two seasons: O3 reduced the aboveground biomass growth and N modulated this response. Gas exchange rates presented a high inter-specific variability and important inter-annual fluctuations as a result of varying growing conditions during the two years. The AOT40-based relationships were not statistically significant except when the highest N input was considered alone. In contrast, PODy-MS relationships were all significant but for the lowest N input level. The influence of the N input on the exposure- and dose-response relationships implies that N can modify the O3 CLe. However, this is an aspect that has not been considered so far in the methodologies for establishing O3 CLe. Averaging across N input levels, a multi-species O3 CLe (CLef-MS) is proposed POD1-MS = 7.9 mmol m-2, accumulated over 1.5 month with a 95% confidence interval of (5.9, 9.8). Further efforts will be needed for comparing the CLef-MS with current O3 CLef based on single species responses.

Heterogeneous responses to ozone and nitrogen alter the species composition of Mediterranean annual pastures.

Air pollution represents a threat to biodiversity throughout the world and particularly in the Mediterranean area, where high tropospheric ozone (O3) concentrations and atmospheric nitrogen (N) deposition are frequently recorded. Mediterranean annual pastures are among the most important ecosystems in southern Europe due to their high biodiversity and extension. Aiming to study the responses of these communities to the main atmospheric pollutants in the Mediterranean region, an experimental study was performed in an open-top chamber (OTC) facility. A mixture of six species representative of annual pastures was grown under field conditions inside the OTC. Plants were exposed for 39 days to four O3 treatments and three doses of N. The species responded heterogeneously to both factors. Legumes did not react to N but were very sensitive to O3: Trifolium species responded negatively, while Ornithopus responded positively, taking advantage of the greater sensitivity of clovers to O3. The grasses and the herb were more tolerant of O3 and grasses were the most responsive to N. Significant interactions between factors indicated a loss of effectiveness of N in O3-polluted atmospheres and an ability of O3 to counterbalance the damage induced by N input, but both effects were dependent on O3 and N levels. The inclusion of plant competition in the experimental design was necessary to reveal results that would otherwise be missed, such as the positive growth responses under elevated O3 levels. Surprisingly, competition within the legume family played the most important role in the overall response of the annual community to O3. Both tropospheric O3 and N deposition should be considered important drivers of the structure and biodiversity of Mediterranean annual pastures.

[Japanese cedar pollen in house dust].

Caring for oneself against Japanese cedar pollinosis is important as well as receiving medical-care. Although the importance of avoiding pollen is described in the guideline for nasal allergy medical treatment, however, there is no information for effective dust cleaning for the home. This study examined how many cedar pollens were included in indoor dust in order to obtain basic data whether dust removal for cedar pollen is available for pollinosis suffers. As a result, the study found that there were many Japanese cedar pollens in indoor dust even before the pollen season. Cedar pollen increased with the increasing number of airborne pollen. The highest number of pollen found in one week was approximately 450 pollens in a square meter of a living room floor. The study concluded that cleaning is one of the best way to remove Japanese cedar pollens found in indoor dust.

Perception of relation of stimuli locations successively flashed before saccade.

Based on localization error for a single perisaccadic flash, eye position signal is supposed to change more slowly than physical eye position. Nevertheless, a flicker is not perceived as moving in accordance with localization error for a single flash. We carried out two experiments to investigate this problem. Experiment 1 examined how a single flash or a flicker presented before saccade was perceived. The results showed that the flicker was not perceived as moving, although mislocalization for the single flash increases gradually before saccade. Experiment 2 was a vernier test of two stimuli successively flashed before the saccade. The results showed that the point of subjective equality shifted in accordance with the mislocalization for a single perisaccadic flash when the interstimulus interval (ISI) was about 2 s; however, it did not shift when the ISI was 78 ms. Comparison between these results and previous studies suggests that the relation of the locations of successive flashes before saccade is perceived exocentrically when the ISI and stimulus onset asynchrony between flashes was short.

Month of birth, atopic disease, and atopic sensitization.

BACKGROUND: Japanese cedar (Cryptmeria japonica; CJ) pollen and house dust mites are the two important aeroallergens in Japan. However, no epidemiological survey has been performed in Japan to investigate the relationship between month of birth and manifestations of allergic disease and sensitization. OBJECTIVE: This study evaluates the correlation between month of birth and sensitization to aeroallergens or the occurrence of allergic disease on 755 Japanese school children aged 12-13 years. METHODS: The personal history of atopic disease (bronchial asthma, allergic rhinitis, eczema, and allergic conjunctivitis) as recorded by questionnaires was investigated in relation to total serum IgE and specific IgE toward house dust mites and CJ pollen. RESULTS: Positive specific IgE toward house dust mites was significantly less prevalent in the children born between January and March than those born during the rest of the year (p < 0.01). Positive specific IgE toward CJ pollen was significantly more prevalent in the children born between December and January than those born during the rest of the year (p < 0.05). High total IgE was less prevalent in the children born between February and April than in children born during the rest of the year (p = 0.05). The prevalence of bronchial asthma was 26.2% among children born between November and December, compared with a ratio of 17.3% among children born during the rest of the year (p < 0.05). A significantly higher proportion of the children with allergic rhinitis was born between August and October than during the rest of the year (p < 0.05). The prevalence of allergic conjunctivitis was 15.8% among the children who were born between December and January, compared with 9.1% among children born during the rest of the year (p < 0.01). No relationship between prevalence of eczema and season of birth was found. CONCLUSION: Month of birth appears to influence the risk in the development of allergic sensitization and atopic diseases. The findings concerning higher CJ pollen sensitization in children born in the months that proceed the CJ pollen seasons are as evident as the house-dust-mite-related findings.

[An office technique for myringoplasty without the use of fibrin glue].

A simple method for office closure of eardrum perforation using an atero-collagen graft used for dermal defects (Terdermis) without fibrin glue was developed. Eardrum perforations were successfully closed in 71.4% of all cases (63 ears) after the initial treatment. Neither skin incision nor the use of temporal fascial grafts was necessary in this method. The merit of the method is that there is no possibility of blood infection because no blood materials are used.

[The positivity rate of specific IgE antibody to Japanese cedar pollen in Wakayama Prefecture].

The incidence of Japanese cedar pollinosis has been increasing each year in Japan. Japanese cedar pollinosis is a state of allergic response, mediated by IgE. So, it is important to know the state of sensitization against Japanese cedar pollen. The subjects were 1321 nonselective cases who were more than 16 years of age and who live in Wakayama Prefecture. Specific IgE antibodies to Japanese cedar pollen were measured by Lumiward immunoassay system. The results showed that positivity for sera class 2 or higher was 30.9%. Furthermore, the positivity in 1995 was higher than the positivity in either 1985 (13.9%) or 1990 (18.3%). The incidence of specific IgE antibody positivity was higher in males. Also the age distribution of the positivity was highest in the 20-29 years old group, and the positivity was decreased with age. We examined the kinds of factors influencing the positivity of specific IgE antibodies. However, the relation between the positivity of specific IgE antibodies and the various environmental factors was unclear.