Demonstration of 10−2210^{-22} W Signal Detection Methods in the Microwave Range at Ambient Temperature

The detection of a very faint signal in a noisy environment is of considerable interest in different applications including antihydrogen spectroscopy and also microwave axion and ‘hidden photon’ detection. We demonstrate with a very simple setup using a commercial signal generator and an FFT signal analyzer the detection of a microwave signal of 10**-22 W at ambient temperature

Dishonest signals of strength in male slender crayfish (Cherax dispar) during agonistic encounters

Many animals resolve disputes without combat by displaying signals of potential strength during threatening displays. Presumably, competitors use each other's displays to assess their relative strengths, and current theory predicts that these signals of strength should generally be honest. We tested this prediction by investigating the relationships among morphology, performance, and social dom inance in males of the slender crayfish Cherax dispar. Crayfish routinely use their enlarged front claws (chelae) for both intimidation and fighting, making this species ideal for studying the honesty of weapon size. We evaluated five competing models relating morphological and physiological traits to dominance during paired competitive bouts. Based on the best model, larger chelae clearly resulted in greater dominance; however, chela strength had no bearing on dominance. Thus, displays of chela size were dishonest signals of strength, and the enlarged chelae of males seemingly function more for intimidation than for fighting. In addition, an analysis of the performance of isolated chela muscle showed that muscle from male crayfish produced only half the force that muscle from female crayfish produced (236.6 +/- 26.4 vs. 459.5 +/- 71.6 kN m(-2)), suggesting that males invest more in developing larger chelae than they do in producing high-quality chela muscle. From our studies of crayfish, we believe dishonest signaling could play a greater role in territorial disputes than previously imagined

Warm temperature acclimation impacts metabolism of paralytic shellfish toxins from Alexandrium minutum in commercial oysters

© 2015 John Wiley & Sons Ltd. Species of Alexandrium produce potent neurotoxins termed paralytic shellfish toxins and are expanding their ranges worldwide, concurrent with increases in sea surface temperature. The metabolism of molluscs is temperature dependent, and increases in ocean temperature may influence both the abundance and distribution of Alexandrium and the dynamics of toxin uptake and depuration in shellfish. Here, we conducted a large-scale study of the effect of temperature on the uptake and depuration of paralytic shellfish toxins in three commercial oysters (Saccostrea glomerata and diploid and triploid Crassostrea gigas, n = 252 per species/ploidy level). Oysters were acclimated to two constant temperatures, reflecting current and predicted climate scenarios (22 and 27 °C), and fed a diet including the paralytic shellfish toxin-producing species Alexandrium minutum. While the oysters fed on A. minutum in similar quantities, concentrations of the toxin analogue GTX1,4 were significantly lower in warm-acclimated S. glomerata and diploid C. gigas after 12 days. Following exposure to A. minutum, toxicity of triploid C. gigas was not affected by temperature. Generally, detoxification rates were reduced in warm-acclimated oysters. The routine metabolism of the oysters was not affected by the toxins, but a significant effect was found at a cellular level in diploid C. gigas. The increasing incidences of Alexandrium blooms worldwide are a challenge for shellfish food safety regulation. Our findings indicate that rising ocean temperatures may reduce paralytic shellfish toxin accumulation in two of the three oyster types; however, they may persist for longer periods in oyster tissue

Morphological differences between habitats are associated with physiological and behavioural trade-offs in stickleback (Gasterosteus aculeatus)

F.S. and A.J.W.W. were supported by the Australian Research Council, M.M.W. was supported by The University of St Andrews and R.S.J. and J.T. were supported by Coventry UniversityLocal specialization can be advantageous for individuals and may increase the resilience of the species to environmental change. However, there may be trade-offs between morphological responses and physiological performance and behaviour. Our aim was to test whether habitat-specific morphology of stickleback (Gasterosteus aculeatus) interacts with physiological performance and behaviour at different salinities. We rejected the hypothesis that deeper body shape of fish from habitats with high predation pressure led to decreases in locomotor performance. However, there was a trade-off between deeper body shape and muscle quality. Muscle of deeper-bodied fish produced less force than that of shallow-bodied saltmarsh fish. Nonetheless, saltmarsh fish had lower swimming performance, presumably because of lower muscle mass overall coupled with smaller caudal peduncles and larger heads. Saltmarsh fish performed better in saline water (20 ppt) relative to freshwater and relative to fish from freshwater habitats. However, exposure to salinity affected shoaling behaviour of fish from all habitats and shoals moved faster and closer together compared with freshwater. We show that habitat modification can alter phenotypes of native species, but local morphological specialization is associated with trade-offs that may reduce its benefits.Publisher PDFPeer reviewe

Transient Receptor Potential Ion Channels Control Thermoregulatory Behaviour in Reptiles

Biological functions are governed by thermodynamics, and animals regulate their body temperature to optimise cellular performance and to avoid harmful extremes. The capacity to sense environmental and internal temperatures is a prerequisite for the evolution of thermoregulation. However, the mechanisms that enable ectothermic vertebrates to sense heat remain unknown. The recently discovered thermal characteristics of transient receptor potential ion channels (TRP) render these proteins suitable to act as temperature sensors. Here we test the hypothesis that TRPs are present in reptiles and function to control thermoregulatory behaviour. We show that the hot-sensing TRPV1 is expressed in a crocodile (Crocodylus porosus), an agamid (Amphibolurus muricatus) and a scincid (Pseudemoia entrecasteauxii) lizard, as well as in the quail and zebrafinch (Coturnix chinensis and Poephila guttata). The TRPV1 genes from all reptiles form a unique clade that is delineated from the mammalian and the ancestral Xenopus sequences by an insertion of two amino acids. TRPV1 and the cool-sensing TRPM8 are expressed in liver, muscle (transversospinalis complex), and heart tissues of the crocodile, and have the potential to act as internal thermometer and as external temperatures sensors. Inhibition of TRPV1 and TRPM8 in C. porosus abolishes the typically reptilian shuttling behaviour between cooling and heating environments, and leads to significantly altered body temperature patterns. Our results provide the proximate mechanism of thermal selection in terrestrial ectotherms, which heralds a fundamental change in interpretation, because TRPs provide the mechanism for a tissue-specific input into the animals' thermoregulatory response

Gestaltung von Anpassungspfaden im Klimarisikomanagement. Leitfaden für Entscheidungsträgerinnen und Entscheidungsträger

Entscheidungen im lokalen Management von klimabedingten Risiken, wie z.B. im Hochwasserrisikomanagement, erfolgen regelmäßig sehr rasch nach einem Ereignis, u.a. auch aufgrund massiven Drucks der lokalen Bevölkerung. Dabei werden meist Maßnahmen umgesetzt, die allgemein bekannt sind und dem Stand der Technik entsprechen. Diese singulären und sich an der Vergangenheit orientierenden Entscheidungen führen aber dazu, dass sich das Schadenspotential in den Gemeinden und Regionen meist weiterentwickelt und den zukünftigen Herausforderungen im Risikomanagement aufgrund des Klimawandels nur unzureichend genügt. Deshalb ist es wichtig, aktuelle Pfadabhängigkeiten frühzeitig zu erkennen und eine Entkoppelung davon zu erzielen. Nur so kann ein antizipatives Klimarisikomanagement umgesetzt und verstetigt werden, welches auch über einzelne klimabedingte Risiken hinweg agiert. Der Leitfaden „Gestaltung von Anpassungspfaden im Klimarisikomanagement“ dient als mögliche Erweiterung des „Vorsorgechecks Naturgefahren im Klimawandel“, welcher den Status Quo aller in einer Gemeinde möglichen Naturgefahren abhandelt. Dieser Leitfaden richtet sich somit vorrangig an jene österreichischen Gemeinden, die entweder bereits einen solchen „Naturgefahrencheck“ absolviert haben oder dies in Zukunft noch vorhaben. Der Leitfaden schlägt fünf konkrete Schritte vor, um im Anschluss an die Methodik des Naturgefahrenchecks (1) das Bewusstsein für die Zusammenhänge zwischen einzelnen klimabedingten Risiken zu schärfen, (2) aus den bisher gemachten Erfahrungen im Naturgefahrenmanagement für die „neuen“ Risiken zu lernen und (3) gemeinsam konkrete Maßnahmen zu entwerfen und nächste Umsetzungsschritte zu definieren, wie diese Risiken in Zukunft zusammen gedacht und proaktiv angegangen werden können. Der Leitfaden ist so aufgebaut, dass bei Bedarf auch jeder Schritt als einzelnes gesondertes Erweiterungsmodul für den „Vorsorgechecks Naturgefahren im Klimawandel“ dienen kann