Temperature alters the shape of predator–prey cycles through effects on underlying mechanisms

Background Predicting the effects of climate warming on the dynamics of ecological systems requires understanding how temperature influences birth rates, death rates and the strength of species interactions. The temperature dependance of these processes—which are the underlying mechanisms of ecological dynamics—is often thought to be exponential or unimodal, generally supported by short-term experiments. However, ecological dynamics unfold over many generations. Our goal was to empirically document shifts in predator–prey cycles over the full range of temperatures that can possibly support a predator–prey system and then to uncover the effect of temperature on the underlying mechanisms driving those changes. Methods We measured the population dynamics of the Didinium-Paramecium predator–prey system across a wide range of temperatures to reveal systematic changes in the dynamics of the system. We then used ordinary differential equation fitting to estimate parameters of a model describing the dynamics, and used these estimates to assess the long-term temperature dependance of all the underlying mechanisms. Results We found that predator–prey cycles shrank in state space from colder to hotter temperatures and that both cycle period and amplitude varied with temperature. Model parameters showed mostly unimodal responses to temperature, with one parameter (predator mortality) increasing monotonically with temperature and one parameter (predator conversion efficiency) invariant with temperature. Our results indicate that temperature can have profound, systematic effects on ecological dynamics, and these can arise through diverse and simultaneous changes in multiple underlying mechanisms. Predicting the effects of temperature on ecological dynamics may require additional investigation into how the underlying drivers of population dynamics respond to temperature beyond a short-term, acute response.

Temperature influence on the diethylamine sensing abilities of CuO nanoparticles deposited by atmospheric pressure plasma

In this work we present a copper oxide nanostructured analysed as a gas sensor but the focus of the paper is on the temperature dependance of the sensor sensing properties. As a case study temperature dependent diethylamine sensing is presented.The CuO nano flakes were deposited and evenly distributed on intercalated electrodes by an atmospheric pressure plasma source. The sensor was electrically connected to ohmmetre and inserted in an oven chamber where it was isolated from atmosphere and heated to desired tempearuteres. The intrinsic resistnace of the sensor was measured in dependence of the temperature and the temperature change rate. Then the possibility to detect diethylamine was investigated and the sensor response studied. Finally, the temperature dependence of the detection of the amine was explored. It was possible to demonstrate reliable sensing of the amine down to temperatures of 100 °C and below.

Effect of temperature on the binding energy of a shallow hydrogenic impurity in a quantum well wire

In this work, we investigate the variation of the binding energy of an on-axis hydrogenic impurity in a cylindrical semiconductor GaAsalxGa1–xAs quantum well wire (QWW) with temperature, by taking into account the temperature dependance of the electron masses and dielectric constants in the quantum well and potential barrier region as well as the temperature dependence of the barrier height. This investigation is important in understanding the role such impurities can play in determining the transport properties of such systems. The results show enhancement of the binding energy as the temperature is decreased, specially for small values of wire radius.