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Castro-Carranza A.,Rovira i Virgili University | Estrada M.,National Polytechnic Institute of Mexico | Cerdeira A.,National Polytechnic Institute of Mexico | Nolasco J.C.,Hanse Wissenschaftskolleg Institute for Advanced Study | And 4 more authors.
IEEE Transactions on Electron Devices | Year: 2014

We present a compact capacitance model for organic thin-film transistors (OTFTs), which is valid not only in the accumulation regime but also in the partial and total depletion regimes. The parameters applied in the model are analytically extracted from the current-voltage characteristics of the devices, using a previously developed unified model and the parameter extraction method. The overlap capacitance effect is taken into account, and the frequency dependence is considered empirically by means of the insulator permittivity. Comparisons between modeled and experimental gate-to-channel capacitances of staggered upper contact p-channel OTFTs based on P3HT-PMMA and PCDTBT-PMMA show the validity of the model at low and medium frequencies. © 1963-2012 IEEE.


Wang F.-Y.,Taiwan Ocean Research Institute | Fu W.-C.,Academia Sinica, Taiwan | Wang I.-L.,Academia Sinica, Taiwan | Wang I.-L.,National Taiwan University | And 3 more authors.
PLoS ONE | Year: 2014

Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity and opsin gene expression of A. marmorata during upstream migration. Microspectrophotometry analysis revealed that the tropical eel possesses a duplex retina with rod and cone photoreceptors. The λmax of rod cells are 493, 489, and 489 nm in glass, yellow, and wild eels, while those of cone cells are 508, and 517 nm in yellow, and wild eels, respectively. Unlike European and American eels, Asian eels exhibited a blue-shifted pattern of rod photoreceptors during upstream migration. Quantitative gene expression analyses of four cloned opsin genes (Rh1f, Rh1d, Rh2, and SWS2) revealed that Rh1f expression is dominant at all three stages, while Rh1d is expressed only in older yellow eel. Furthermore, sequence comparison and protein modeling studies implied that a blue shift in Rh1d opsin may be induced by two known (N83, S292) and four putative (S124, V189, V286, I290) tuning sites adjacent to the retinal binding sites. Finally, expression of blue-shifted Rh1d opsin resulted in a spectral shift in rod photoreceptors. Our observations indicate that the giant mottled eel is color-blind, and its blue-shifted scotopic vision may influence its upstream migration behavior and habitat choice. © 2014 Wang et al.


Shao Y.T.,Academia Sinica, Taiwan | Shao Y.T.,National Taiwan Ocean University | Chen I.-S.,National Taiwan Ocean University | Yan H.Y.,Academia Sinica, Taiwan | Yan H.Y.,Hanse Wissenschaftskolleg Institute for Advanced Study
Zoological Studies | Year: 2014

Background: The enhanced auditory abilities of certain fish are dependent on specialized hearing structures. Several gas-holding structures, including the suprabranchial chamber, otic gas bladder, and Weberian apparatus-linked gas bladder, have been demonstrated to improve the hearing ability of fish. The walking catfish (Clarias batrachus), a benthic species, is unique in that it has both a suprabranchial chamber (SC) and a Weberian apparatus-linked, encapsulated gas bladder (WGB). This study aimed to investigate the respective roles of these two structures in contributing to the overall hearing ability of walking catfish. Results: The auditory evoked potentials method was used to measure hearing thresholds in intact fish and fish with a deflated WGB and/or SC. Gas removal from the WGB increased auditory thresholds at all frequencies tested (0.4 to 5.0 kHz), whereas injection of water into the SC shifted the threshold only at frequencies below 3.0 kHz. However, such a correlation was not observed for the SC at 4.0 and 5.0 kHz. Conclusions: The findings indicated that both the encapsulated WGB and the SC had an accessory auditory role. However, WGB enhanced hearing abilities in the whole frequency range, whereas SC did not. © 2014 Shao et al.


Shao Y.T.,University of Stockholm | Shao Y.T.,Academia Sinica, Taiwan | Wang F.-Y.,Taiwan Ocean Research Institute | Fu W.-C.,Academia Sinica, Taiwan | And 5 more authors.
PLoS ONE | Year: 2014

Optomotor studies have shown that three-spined sticklebacks (Gasterosteus aculeatus) are more sensitive to red during summer than winter, which may be related to the need to detect the red breeding colour of males. This study aimed to determine whether this change of red light sensitivity is specifically related to reproductive physiology. The mRNA levels of opsin genes were examined in the retinae of sexually mature and immature fish, as well as in sham-operated males, castrated control males, or castrated males implanted with androgen 11-ketoandrostenedione (11 KA), maintained under stimulatory (L16:D8) or inhibitory (L8:D16) photoperiods. In both sexes, red-sensitive opsin gene (lws) mRNA levels were higher in sexually mature than in immature fish. Under L16:D8, lws mRNA levels were higher in intact than in castrated males, and were up-regulated by 11 KA treatment in castrated males. Moreover, electroretinogram data confirmed that sexual maturation resulted in higher relative red spectral sensitivity. Mature males under L16:D8 were more sensitive to red light than males under L8:D16. Red light sensitivity under L16:D8 was diminished by castration, but increased by 11 KA treatment. Thus, in sexually mature male sticklebacks, androgen is a key factor in enhancing sensitivity to red light via regulation of opsin gene expression. This is the first study to demonstrate that sex hormones can regulate spectral vision sensitivity. © 2014 Shao et al.


Shao Y.T.,Academia Sinica, Taiwan | Chang F.Y.,Academia Sinica, Taiwan | Fu W.-C.,Academia Sinica, Taiwan | Yan H.Y.,Academia Sinica, Taiwan | Yan H.Y.,Hanse Wissenschaftskolleg Institute for Advanced Study
Aquaculture Research | Year: 2016

Ocean acidification, resulted from high level of carbon dioxide (CO2) dissolved in seawater, may disturb the physiology of fish in many ways. However, it is unclear how acidification may impact the growth rate and/or growth hormones of marine fish. In this study, we exposed juvenile orange-spotted groupers (Epinephelus coioides) to seawater of different levels of acidification: a condition predicted by the Intergovernmental Panel on Climate Change (pH 7.8-8.0), and a more extreme condition (pH 7.4-7.6) that may occur in coastal waters in the near future. After 6 weeks of exposure, the growth rates of fish in pH 7.4-7.6 were less than those raised in control water (pH 8.1-8.3). Furthermore, exposure at pH 7.4-7.6 increased blood pCO2 and HCO3 - significantly; exposure at pH 7.8-8.0, meanwhile, did not affect acid-base chemistry. Moreover, exposure to pH 7.4-7.6 resulted in lower levels of hepatic igf1 (insulin-like growth factor I) mRNA, but did not affect levels of pituitary gh (growth hormone) or hypothalamus psst2 and psst3 (prepro-somatostatin II and III). The results show that highly acidified seawater suppresses growth of juvenile grouper, which may be a consequence of reduced levels of IGF-1, but not due to diminished growth hormone release. © 2016 John Wiley & Sons Ltd.


PubMed | National Taiwan Ocean University, University of Stockholm, Hanse Wissenschaftskolleg Institute for Advanced Study, Kagoshima University and 2 more.
Type: Journal Article | Journal: PloS one | Year: 2014

Optomotor studies have shown that three-spined sticklebacks (Gasterosteus aculeatus) are more sensitive to red during summer than winter, which may be related to the need to detect the red breeding colour of males. This study aimed to determine whether this change of red light sensitivity is specifically related to reproductive physiology. The mRNA levels of opsin genes were examined in the retinae of sexually mature and immature fish, as well as in sham-operated males, castrated control males, or castrated males implanted with androgen 11-ketoandrostenedione (11 KA), maintained under stimulatory (L16:D8) or inhibitory (L8:D16) photoperiods. In both sexes, red-sensitive opsin gene (lws) mRNA levels were higher in sexually mature than in immature fish. Under L16:D8, lws mRNA levels were higher in intact than in castrated males, and were up-regulated by 11 KA treatment in castrated males. Moreover, electroretinogram data confirmed that sexual maturation resulted in higher relative red spectral sensitivity. Mature males under L16:D8 were more sensitive to red light than males under L8:D16. Red light sensitivity under L16:D8 was diminished by castration, but increased by 11 KA treatment. Thus, in sexually mature male sticklebacks, androgen is a key factor in enhancing sensitivity to red light via regulation of opsin gene expression. This is the first study to demonstrate that sex hormones can regulate spectral vision sensitivity.


Boning P.,University of Oldenburg | Boning P.,Max Planck Institute for Marine Microbiology | Shaw T.,University of South Carolina | Shaw T.,Hanse Wissenschaftskolleg Institute for Advanced Study | And 3 more authors.
Geochimica et Cosmochimica Acta | Year: 2015

Trace metals involved in biological cycling (e.g. Cd, Cu, Ni, Zn) typically accumulate in upwelling sediments due to a high productivity-related particle flux and an enhanced preservation at depth. However, poor constraint on the contribution of lithogenic metal fraction, early diagenetic transformation processes and anthropogenic metal inputs may complicate sediment metal signatures. The identification of source and accumulation mechanisms is essential to the validation of these metals as productivity proxies.Here we combine data from various short cores (upper 50. cm) and two longer cores of organic-rich upwelling sediments (Peru, Namibia, Chile and Gulf of California), which suggest a highly significant, linear and uniform relationship between Ni and total organic carbon (TOC). The overall high Ni enrichment may be explained by the occurrence of diatoms, which dominate productivity in these systems. The Peru surface sediments (upper 2. cm) show a less pronounced Ni-TOC relationship and support a transition between lower Ni/TOC ratio of East Pacific water column particles and the higher Ni/TOC ratio observed in deeper sediments. In Peru surface sediments, the process is confirmed as a stoichiometric relation between Ni and total chlorins (the immediate degradation products of chlorophyll pigments), which is not observed for Cu or Zn.Our data strongly support previous findings that Ni is a clear (if not the best) indicator of the organic sinking flux. This is also due to the fact that Ni signatures undergo less alteration associated with sulfur and manganese cycling and low contribution from anthropogenic sources. The apparently exclusive Ni-chlorin stoichiometry suggests that Ni may be associated with enzymes that are involved in photoautotrophic production, which underlines the previous finding from laboratory experiments and field work that diatoms have a dominant role in marine Ni cycling. The Ni/chlorin ratio increases with increasing sediment depth suggesting that chlorins are effected by on-going diagenesis. Therefore, Ni may serve as a reliable indicator of the original chlorophyll flux rather than chlorins. The very good correlation between Ni and TOC and the preferential preservation of Ni over TOC justify previous (paleo)productivity estimates based on Ni accumulation. © 2015.


Braden H.W.,University of Edinburgh | Enolski V.Z.,Hanse Wissenschaftskolleg Institute for Advanced Study | Enolski V.Z.,Ukrainian Academy of Sciences
Theoretical and Mathematical Physics | Year: 2010

We develop the Ercolani-Sinha construction of SU(2) monopoles, which provides a gauge transform of the Nahm data. © 2010 MAIK/Nauka.

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