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Populations or species exploiting different habitats can differ in sensory perception as a result of divergent adaptation. In bony fish, the water current is perceived via neuromasts, the end organ of the lateral line system. Although fish in different habitats are known to vary in neuromasts, we know little about the genetic basis for such variation. Here, we investigate the genetic basis for variation in supraorbital neuromasts in a hybrid zone between the Japanese gobies Gymnogobius breunigii and Gymnogobius castaneus. The former has supraorbital canal neuromasts with six cephalic pores, whereas the latter has only superficial neuromasts with no canals or pores in the supraorbital region. Our genomic analysis showed that G. breunigii and G. castaneus occur mainly in the lower and mid/upper reaches, respectively. In a river in northern Japan, hybrids were found at the sites between the habitats of the two species. These hybrids exhibited anomalies of cephalic pores. Using this hybrid zone, we conducted genome-wide association studies and identified one locus significantly associated with the number of pores. Genomic cline analysis in the hybrid zone demonstrated that this locus exhibited a higher introgression rate compared with the genomic background, indicating the possibility of adaptive introgression. [ABSTRACT FROM AUTHOR]

ABSTRACT Topmouth gudgeon ( Pseudorasbora parva) is widely known as a highly invasive freshwater fish and has expanded from East Asia (native range) to Central Asia, Europe and Northern Africa (introduced range). Although the relationship between the occurrence of P. parva and its habitat conditions remains unclear, information on factors affecting its distribution, especially in its native range, is important for predicting its expansion., This study provides primary information on the distribution of P. parva in rivers and agricultural canals in northern Kyushu Island, Japan, where the fish is native. Fuzzy habitat preference models (FHPMs) and Random Forests (RF) were applied to link landscape features to the distribution of P. parva based on field observation data collected from two distinct ecoregions, the north-western (NW) and north-eastern (NE) parts of Kyushu Island., The results show a clear habitat preference of P. parva for areas with a lower elevation, a gentler slope and a smaller number of river-to-river connections as general landscape features across the ecoregions. Weak preferences are observed for sites with a higher number of river-to-canal connections, a higher canal network index, a larger area of paddy fields, a larger residential area, more crop fields and fewer forests and orchards. Of these site-specific features, five landscape features - elevation, slope, canal network index, area of paddy fields, and presence of forests and orchards - are identified as the most important features for predicting the distribution of P. parva., The general and specific habitat preference information, as demonstrated in this study, may be important in biogeography and invasion ecology. Further research is needed to accumulate information for a better understanding of the invasion ecology and the design of improved management and control strategies against P. parva., Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Many reports about the effect of aging on hearing results after tympanoplasty have been published. However, they have not been evaluated comprehensively, i.e. by taking into consideration other aspects which also affect the outcome. In this study, the effect of aging on hearing results after canal wall reconstruction tympanoplasty was assessed in 236 consecutive ears of 213 patients > 20 years old with middle ear cholesteatoma. The elderly group (n = 34), defined as patients ≥ 60 years old, was compared to the younger groups in terms of hearing results of postoperative hearing level, hearing gain, A-B gap and change in bone conduction hearing level at 4000 Hz after adjustment for age, gender, staged operation, preoperative hearing level and type of tympanoplasty, all of which affect hearing results, using the generalized linear regression method. Postoperative hearing level and hearing gain were found to be better amongst patients aged 20-29 and 30-39 years than in the elderly group, whilst A-B gap did not differ between all age categories. Within the elderly group, air conduction hearing level was shown to have improved after surgery. Changes in bone conduction hearing level at 4000 Hz were not significantly different between the age groups, suggesting that operative stress, i.e. mechanical stress or ossicular manipulation stress, does not aggravate sensorineural hearing loss in the elderly. We conclude that surgeons should be encouraged to perform tympanoplasty aimed not only at eradicating the lesion itself but also at improving should be encouraged to perform hearing acuity in the elderly. [ABSTRACT FROM AUTHOR]