Effects of past and current crop management on soil microbial biomass and activity

As soil biota is influenced by a number of factors, including land use and management techniques, changing management practices could have significant effects on the soil microbial properties and processes. An experiment was conducted to investigate differences in soil microbiological properties caused by long- and short-term management practices. Intact monolith lysimeters (0.2 m2 surface area) were taken from two sites of the same soil type that had been under long-term organic or conventional crop management and were then subjected to the same 2½-year crop rotation (winter barley (Hordeum vulgare L.), maize (Zea mais L.), lupin (Lupinus angustifolius L.) rape (Brassica napus L. ssp. oleifera)) and two fertiliser regimes (following common organic and conventional practices). Soil samples were taken after crop harvest and analysed for microbial biomass C and N, microbial activity (fluorescein diacetate hydrolysis, arginine deaminase activity, dehydrogenase activity) and total C and N. The incorporation of the green manure stimulated growth and activity of the microbial communities in soils of both management histories. Soil microbial properties did not show any differences between organically and conventionally fertilised soils, indicating that crop rotation and plant type had a larger influence on the microbial biomass and enzyme activities than fertilisation. Initial differences in microbial biomass declined, while the effects of farm management history were still evident in enzyme activities and total C and N. Links between enzyme activities and microbial biomass C varied depending on treatment indicating differences in microbial community composition

Tuneable superradiant thermal emitter assembly

Superradiance is a signature effect in quantum photonics that explains the collective enhancement of emission power by a factor of N2 when N emitters are placed in subwavelength proximity. Although the effect is inherently transient, successful attempts have been made to sustain it in the steady-state regime. Until recently, the effects of superradiance were not considered to be applicable to thermal emitters due to their intrinsic incoherent nature. Novel nanophotonic thermal emitters display favourable coherent characteristics that enable them to obey principles of superradiance. However, published analytical work on conventional superradiant thermal emitter assemblies show an anomalous power scaling of 1/N and therefore, increasing the number of thermal emitters leads to a degeneration of power at resonance. This phenomenon immediately renders the effect of thermal superradiance futile since it cannot outperform non-coupled emitters in the steady-state regime. We propose an alternative assembly of thermal emitters with specific features that improves the power scaling while maintaining the effects of superradiance. In essence, we show that our emitter assembly achieves superior power delivery over conventional non-coupled emitter systems at resonance. Additionally, this assembly has the ability to be tuned to operate at specific resonant frequencies, which is a vital requirement for applications such as photothermal cancer therapy

Tuneable superradiant thermal emitter assembly

Superradiance is a signature effect in quantum photonics that explains the collective enhancement of emission power by a factor of N2 when N emitters are placed in subwavelength proximity. Although the effect is inherently transient, successful attempts have been made to sustain it in the steady-state regime. Until recently, the effects of superradiance were not considered to be applicable to thermal emitters due to their intrinsic incoherent nature. Novel nanophotonic thermal emitters display favourable coherent characteristics that enable them to obey principles of superradiance. However, published analytical work on conventional superradiant thermal emitter assemblies show an anomalous power scaling of 1/N and therefore, increasing the number of thermal emitters leads to a degeneration of power at resonance. This phenomenon immediately renders the effect of thermal superradiance futile since it cannot outperform non-coupled emitters in the steady-state regime. We propose an alternative assembly of thermal emitters with specific features that improves the power scaling while maintaining the effects of superradiance. In essence, we show that our emitter assembly achieves superior power delivery over conventional non-coupled emitter systems at resonance. Additionally, this assembly has the ability to be tuned to operate at specific resonant frequencies, which is a vital requirement for applications such as photothermal cancer therapy