Science

This study investigates the potential for spatial heterogeneity in substrate depth as a means to increase coexistence of functionally diverse plant species on green roofs. A treatment with heterogeneous substrate depths of 15 cm ridges alternating with 5 cm furrows was vegetated using hydroseed mixtures of forbs and graminoids on the ridges and pre-vegetated mats with succulent species (Sedum dominant) on the furrows. This was compared to a treatment with homogeneous substrate depth of 10 cm covered with pre-vegetative mats of succulents that is representative of a standard extensive green roof design. Both treatments reached high plant cover and successful coexistence was observed between the different growth forms in the mixed vegetation treatment over two growing seasons. The mixed vegetation treatment performed similar stormwater retention and substrate temperature ecosystem services in comparison to the succulent-only treatment. The hydroseeding method showed potential for use in green roof applications. Future research on the effects of substrate depth and topography and hydroseeding on green roofs on a larger scale is needed to determine the validity of these methods in industrial applications.

Exoplanet research has progressed to where direct observations are not only possible, but effective. Data from exoplanet observations provide insight into planetary system dynamics and evolution, and can be representative of local solar system processes. If present, the study of exoplanet atmospheres can provide further information about a system’s composition and potential biosignatures. X-ray observations of exoplanets can detect atmospheric emission resulting from interaction with radiation and solar wind from the host star. The recently discovered terrestrial exoplanet, K Cancri b, is an excellent candidate for atmospheric analysis, due to similarities to the Earth–Sun system. Proposed observations with Chandra will attempt to detect, identify, and spectroscopically analyse K Cancri b’s atmosphere, if present, leading to further research.

Good random number generators (RNGs) are required for many applications in science and industry. Random numbers can be created in two ways: with a computer algorithm known as a pseudo-random number generator (PRNG), or by measuring physical phenomena which behave randomly, such as quantum mechanical or chaotic systems. However, PRNGs are deterministic in nature and cannot produce truly random output, while physical RNGs can. Three physical RNGs were constructed: a Chua circuit, an electrical circuit which exhibits chaos; an avalanche circuit, which produces a noisy electrical signal; and a radioactive decay counter. Each RNG produced output in the form of ASCII files containing 0s and 1s. The randomness of the data was assessed using the open source statistical test suite rngtest.

Alzheimer’s Disease (AD) is a form of dementia that affects a person’s cognitive ability. It is characterized by the rapid decline of cognition. The first case of AD was reported in 1907 but, even 100 years later, very little is known about the cause of the disease.

The human body plays host to a large and diverse group of microbial inhabitants. The intestinal system is certainly no exception.