The macroecology of animal versus wind pollination: ecological factors are more important than historical climate stability

Background: The relative frequency of wind and animal pollinated plants is non-randomly distributed across the globe and numerous hypotheses have been raised for the greater occurrence of wind pollination in some habitats and towards higher latitudes. To date, however, there has been no comprehensive global investigation of these hypotheses. Aims: Investigating a range of hypotheses for the role of biotic and abiotic factors as determinants of the global variation in animal versus wind pollination. Methods: We analysed 67 plant communities ranging from 70º North to 34º South. For these we determined habitat type, species richness, insularity, topographic heterogeneity, current climate and Late-Quaternary climate change. The predictive effects of these factors on the proportion of wind- and animal-pollinated plants were tested using correlations, ordinary least squares (OLS) and logistic regression analyses with information-theoretic model selection. Results: The proportion of animal-pollinated plant species was positively associated with plant species richness and current temperature. Furthermore, in forest, animal pollination was positively related to precipitation. Historical climate was only weakly and idiosyncratically correlated with animal pollination. Conclusion: Results were consistent with the hypothesised reduced chance for wind-transported pollen reaching conspecific flowers in species-rich communities, fewer constraints on nectar production in warm and wet habitats, and reduced relative effectiveness of wind dispersal in humid areas. There was little evidence of a legacy of historical climate change affecting these patterns

Test person operated 2-Alternative Forced Choice Audiometry compared to traditional audiometry

  Background:With a newly developed technique, hearing thresholds can be estimated with a system operated by the test persons themselves. This technique is based on the 2 Alternative Forced Choice paradigm known from the psychoacoustic research theory. Test persons can operate the system very easily themselves. Furthermore the system uses the theories behind the methods of maximum-likelihood fitting of the most probable psychometric function and a modification of the well known up-down methods in the estimation of the hearing thresholds. The combination of the 2AFC paradigm and the maximum-likelihood and up-down methods has proven effective and reliable even under suboptimal test settings. In non-optimal testing conditions i.e. as a part of a hearing conservation programme the headphone Sennheiser HDA-200 has been used as it contains hearing protection. This test-method has been validated as a comparison with traditional audiometry. A series of 30 persons (60 ears) have conducted traditional audiometry as well as self-operated 2AFC-audiometry. Test subjects are normal as well as moderately hearing impaired people. The different thresholds are compared. Results:2 AFC Audiometry is reliable and comparable to traditional audiometry. 2AFC audiometry tends to give thresholds 1-2 dB lower compared to traditional audiometry. In general standard deviations between the two test methods are below 4.5 dB for frequencies from (250-4000 Hz) and up to 6.7 dB for frequencies above 4000 Hz. Results from test-retest studies of 2AFC audiometry are comparable to test-retest results known from traditional audiometry under standard clinical settings. Conclusions2 Alternative Forced Choice audiometry can be a reliable alternative to traditional audiometry especially under certain circumstances, where it can be difficult to get skilled technical assistance to conduct the audiometry. </p

Test person operated 2-Alternative Forced Choice Audiometry compared to traditional audiometry

  Background:With a newly developed technique, hearing thresholds can be estimated with a system operated by the test persons themselves. This technique is based on the 2 Alternative Forced Choice paradigm known from the psychoacoustic research theory. Test persons can operate the system very easily themselves. Furthermore the system uses the theories behind the methods of maximum-likelihood fitting of the most probable psychometric function and a modification of the well known up-down methods in the estimation of the hearing thresholds. The combination of the 2AFC paradigm and the maximum-likelihood and up-down methods has proven effective and reliable even under suboptimal test settings. In non-optimal testing conditions i.e. as a part of a hearing conservation programme the headphone Sennheiser HDA-200 has been used as it contains hearing protection. This test-method has been validated as a comparison with traditional audiometry. A series of 30 persons (60 ears) have conducted traditional audiometry as well as self-operated 2AFC-audiometry. Test subjects are normal as well as moderately hearing impaired people. The different thresholds are compared. Results:2 AFC Audiometry is reliable and comparable to traditional audiometry. 2AFC audiometry tends to give thresholds 1-2 dB lower compared to traditional audiometry. In general standard deviations between the two test methods are below 4.5 dB for frequencies from (250-4000 Hz) and up to 6.7 dB for frequencies above 4000 Hz. Results from test-retest studies of 2AFC audiometry are comparable to test-retest results known from traditional audiometry under standard clinical settings. Conclusions2 Alternative Forced Choice audiometry can be a reliable alternative to traditional audiometry especially under certain circumstances, where it can be difficult to get skilled technical assistance to conduct the audiometry. </p

Test person operated 2-Alternative Forced Choice Audiometry compared to traditional audiometry

  Background:With a newly developed technique, hearing thresholds can be estimated with a system operated by the test persons themselves. This technique is based on the 2 Alternative Forced Choice paradigm known from the psychoacoustic research theory. Test persons can operate the system very easily themselves. Furthermore the system uses the theories behind the methods of maximum-likelihood fitting of the most probable psychometric function and a modification of the well known up-down methods in the estimation of the hearing thresholds. The combination of the 2AFC paradigm and the maximum-likelihood and up-down methods has proven effective and reliable even under suboptimal test settings. In non-optimal testing conditions i.e. as a part of a hearing conservation programme the headphone Sennheiser HDA-200 has been used as it contains hearing protection. This test-method has been validated as a comparison with traditional audiometry. A series of 30 persons (60 ears) have conducted traditional audiometry as well as self-operated 2AFC-audiometry. Test subjects are normal as well as moderately hearing impaired people. The different thresholds are compared. Results:2 AFC Audiometry is reliable and comparable to traditional audiometry. 2AFC audiometry tends to give thresholds 1-2 dB lower compared to traditional audiometry. In general standard deviations between the two test methods are below 4.5 dB for frequencies from (250-4000 Hz) and up to 6.7 dB for frequencies above 4000 Hz. Results from test-retest studies of 2AFC audiometry are comparable to test-retest results known from traditional audiometry under standard clinical settings. Conclusions2 Alternative Forced Choice audiometry can be a reliable alternative to traditional audiometry especially under certain circumstances, where it can be difficult to get skilled technical assistance to conduct the audiometry. </p