(C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: AR-13324 mouse 2652-2661, 2011″
“Magnetic properties such as Curie temperature (T(C)), saturation magnetization (M(s)), remanent magnetization (M(r)), and coercivity (H(c)) of nanoparticles of magnesium ferrites (MgFe(2)O(4)) were studied in a broad range of temperatures varying from room temperature to 800 K. The magnetization decreases with increasing temperature, approaching 0 at similar to 750 K. The Curie temperature, determined by means of the inverse susceptibility versus temperature, was similar to 738 K. The saturation magnetization, coercivity, and remanence decreased with increasing temperature, being close to
0 at temperatures near T(C). However, for temperatures 100 K above room temperature, these magnetic properties were still the same as those at room temperature. The coercivity temperature dependence could be expressed in terms of T(3/4), indicating that MgFe(2)O(4) nanoparticles may form a system of random and noninteracting identical particles. The results are discussed in terms of interparticle interactions induced by the thermal fluctuations, cation distribution, and other imperfections that exert fields on Mg(2+) ions that could increase with temperature. (C) 2011 American Institute of Physics.
“The Small molecule library cost carbon cycle modulates climate change, via the regulation of atmospheric CO(2), and it represents one of the most important services provided by ecosystems. However, considerable uncertainties remain concerning potential feedback between the biota and the climate. In particular, it is unclear how global warming will affect the metabolic balance between the photosynthetic fixation and respiratory release of LDN-193189 CO(2) at the ecosystem scale. Here, we present a combination of experimental field data from freshwater mesocosms,
and theoretical predictions derived from the metabolic theory of ecology to investigate whether warming will alter the capacity of ecosystems to absorb CO(2). Our manipulative experiment simulated the temperature increases predicted for the end of the century and revealed that ecosystem respiration increased at a faster rate than primary production, reducing carbon sequestration by 13 per cent. These results confirmed our theoretical predictions based on the differential activation energies of these two processes. Using only the activation energies for whole ecosystem photosynthesis and respiration we provide a theoretical prediction that accurately quantified the precise magnitude of the reduction in carbon sequestration observed experimentally. We suggest the combination of whole-ecosystem manipulative experiments and ecological theory is one of the most promising and fruitful research areas to predict the impacts of climate change on key ecosystem services.