Historical contingency in species interactions: towards niche-based predictions.

The way species affect one another in ecological communities often depends on the order of species arrival. The magnitude of such historical contingency, known as priority effects, varies across species and environments, but this variation has proven difficult to predict, presenting a major challenge in understanding species interactions and consequences for community structure and function. Here, we argue that improved predictions can be achieved by decomposing species' niches into three components: overlap, impact and requirement. Based on classic theories of community assembly, three hypotheses that emphasise related, but distinct influences of the niche components are proposed: priority effects are stronger among species with higher resource use overlap; species that impact the environment to a greater extent exert stronger priority effects; and species whose growth rate is more sensitive to changes in the environment experience stronger priority effects. Using nectar-inhabiting microorganisms as a model system, we present evidence that these hypotheses complement the conventional hypothesis that focuses on the role of environmental harshness, and show that niches can be twice as predictive when separated into components. Taken together, our hypotheses provide a basis for developing a general framework within which the magnitude of historical contingency in species interactions can be predicted

Switching dynamics of a magnetostrictive single-domain nanomagnet subjected to stress

The temporal evolution of the magnetization vector of a single-domain magnetostrictive nanomagnet, subjected to in-plane stress, is studied by solving the Landau-Lifshitz-Gilbert equation. The stress is ramped up linearly in time and the switching delay, which is the time it takes for the magnetization to flip, is computed as a function of the ramp rate. For high levels of stress, the delay exhibits a non-monotonic dependence on the ramp rate, indicating that there is an {\it optimum} ramp rate to achieve the shortest delay. For constant ramp rate, the delay initially decreases with increasing stress but then saturates showing that the trade-off between the delay and the stress (or the energy dissipated in switching) becomes less and less favorable with increasing stress. All of these features are due to a complex interplay between the in-plane and out-of-plane dynamics of the magnetization vector induced by stress

Characterization of SiGe/Si Heterostructures Formed by Ge+ and C+ Implantation

Formation of SiGe/Si heterostructures by germanium ion implantation was investigated. A germanium‐implanted layer was grown epitaxially in the solid phase by thermal annealing. Two kinds of crystalline defects were observed. One is a misfit dislocation, and the other is a residual dislocation caused by ion bombardment. The p‐n junction formed in the SiGe layer has a leakage current three orders of magnitude larger than that of a pure Si p‐n junction fabricated with an identical process except for the Ge+ implantation. Carbon doping in the SiGe layer improves its crystalline quality and the junction characteristics

The investigation into the energy consumption in some Japanese fisheries and the measures to reduce CO2 emissions

Japan’s fish production volume in 2008 was 5.59million tons, it accounted for 4% of world’s production and consisted of catch (4.40million tons) and aquaculture (1.19 million tons). For the far sea fishery, its’ fishing grounds are in domestic and foreign countries’ exclusive economic zone and international waters, since the total production volume of this fishery has been declining, offshore and coastal fishery have become mainly in Japan. In this study, the estimation of the energy consumptions in a kelp aquaculture and three types of fisheries, such as squid, fixed net and gill net, is done for comparison to the consumptions of fisheries in foreign countries. The result reveals that the characteristics of these fisheries’ energy consumptions and the measures for reductions of energy use. Furthermore, in Minamikayabe as surveyed fishing village, the carbon dioxide balance in this village is evaluated. The carbon dioxide emissions from the energy (fuel and electricity) use and the escape Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs) from freezers, refrigerators and ice manufacture machines in the village are calculated. Meanwhile, as forests and oceans are carbon dioxide sinks, it is possible to estimate the volume of carbon dioxide stored by woods and seaweed along the coast. Finally, several measures for carbon dioxide reductions are shown.