3D Imaging of Gems and Minerals by Multiphoton Microscopy

Many optical approaches have been used to examine the composition and structure of gemstones, both recently and throughout history. The nonlinear optical behavior of different gemstones has not been investigated, and the higher order terms to the refractive index represent an unused tool for qualifying and examining a stone. We have used a multiphoton microscope to examine the nonlinear optical properties of 36 different gemstones and demonstrate that it is a useful tool for imaging them three-dimensionally up to the millimeter scale below the sample surface. The polarization dependence of second harmonic generation signals was used to examine the crystal orientations inside the minerals.Comment: 9 pages, five figure

Assessing the Health of Richibucto Estuary with the Latent Health Factor Index

The ability to quantitatively assess the health of an ecosystem is often of great interest to those tasked with monitoring and conserving ecosystems. For decades, research in this area has relied upon multimetric indices of various forms. Although indices may be numbers, many are constructed based on procedures that are highly qualitative in nature, thus limiting the quantitative rigour of the practical interpretations made from these indices. The statistical modelling approach to construct the latent health factor index (LHFI) was recently developed to express ecological data, collected to construct conventional multimetric health indices, in a rigorous quantitative model that integrates qualitative features of ecosystem health and preconceived ecological relationships among such features. This hierarchical modelling approach allows (a) statistical inference of health for observed sites and (b) prediction of health for unobserved sites, all accompanied by formal uncertainty statements. Thus far, the LHFI approach has been demonstrated and validated on freshwater ecosystems. The goal of this paper is to adapt this approach to modelling estuarine ecosystem health, particularly that of the previously unassessed system in Richibucto in New Brunswick, Canada. Field data correspond to biotic health metrics that constitute the AZTI marine biotic index (AMBI) and abiotic predictors preconceived to influence biota. We also briefly discuss related LHFI research involving additional metrics that form the infaunal trophic index (ITI). Our paper is the first to construct a scientifically sensible model to rigorously identify the collective explanatory capacity of salinity, distance downstream, channel depth, and silt-clay content --- all regarded a priori as qualitatively important abiotic drivers --- towards site health in the Richibucto ecosystem.Comment: On 2013-05-01, a revised version of this article was accepted for publication in PLoS One. See Journal reference and DOI belo

The scientific basis of marine fish farm regulation

As aquaculture expands, regulation to prevent environmental damage is an essential requirement for sustainability. In this paper, we discuss three aspects of aquaculture regulation pertaining to 1) protection of other resource users, 2) protection of ecosystem structure (conservation), and 3) protection of ecosystem function (recycling). Some of the approaches taken to regulation of aquaculture in several countries are presented, emphasizing the need for these to be based firmly in a good scientific understanding of the ecosystem and the processes by which it interacts with aquaculture

Student Project Environmental influences on box blight epidemics

Calonectria pseudonaviculata and C. henricotiae are two recently differentiated fungal species responsible for box blight, a disease that threatens the Buxus genus. Infection can be introduced to gardens on new plants and is spread through the use of tools. The fungus survives on stem lesions and fallen leaves when spores are dispersed by rainsplash. In this study, 195 Calonectria UK isolates collected by the Royal Horticultural Society (RHS) Advisory Service were identified to species level. Detached stem assays were performed to assess how long stem and leaf lesions remain infectious, and their sensitivity to fungicides. A survey was also carried out at three National Trust properties on the effect of clipping on box blight distribution and severity. It was found that C. henricotiae was only present in and after 2011. C. henricotiae is more thermotolerant, and the increase in prevalence may be a result of increasing temperature and longer dry spells in the UK. Sporulation could occur multiple times on both stem and leaf lesions in humid conditions, although spore production dropped markedly after six sporulation events. Fungicides were effective at preventing spore production on stem lesions. Long dry spells may also reduce Calonectria’s ability to sporulate, leading to limited box blight spread between plants

A system in ruins; the Victorian asylums of Britain

Despite its closure prior to the beginning of the 21st century, echoes of the county and district asylum system still remain across Britain. These grand architectural monoliths housed hundreds of people in various sites at their peak, across the countryside of England, Ireland, Scotland and Wales, and offered care to mental health patients for over a century. Despite this, many will know the asylum complexes from whistle-blower accounts or newspaper articles declaring them unfit for purpose and highlighting incidents where negligence was commonplace. Furthermore, the fictional renditions of asylums in films, novels and video games has resulted in a lingering disparity between the asylums’ heritage, and the history as more commonly depicted and digested by the public. The cultural perception of asylums is such that the sites now act as a focal point for perceived wrongdoing in past mental health care. Consequently, the sites retain a negative ambiance, brought about by the stigma shown towards these vast institutions, now lying derelict. This thesis will focus on the architecture of the asylum buildings, which will allow a discussion in to the stigma of asylums and the extent to which it is unfounded, instead based on the fictional portrayal of the asylum sites, and not the institutions themselves

Endophytic Trichoderma spp. can protect strawberry and privet plants from infection by the fungus Armillaria mellea

Armillaria mellea is an important fungal pathogen worldwide, affecting a large number of hosts in the horticulture and forestry industries. Controlling A. mellea infection is expensive, labour intensive and time-consuming, so a new, environmentally friendly management solution is required. To this effect, endophytic Trichoderma species were studied as a potential protective agent for Armillaria root rot (ARR) in strawberry and privet plants. A collection of forty endophytic Trichoderma isolates were inoculated into strawberry (Fragaria × ananassa) plants and plant growth was monitored for two months, during which time Trichoderma treatment had no apparent effect. Trichoderma-colonised strawberry plants were then inoculated with A. mellea and after three months plants were assessed for A. mellea infection. There was considerable variation in ARR disease levels between plants inoculated with different Trichoderma spp. isolates, but seven isolates reduced ARR below the level of positive controls. These isolates were further tested for protective potential in Trichoderma-colonized privet (Ligustrum vulgare) plants where five Trichoderma spp. isolates, including two highly effective Trichoderma atrobrunneum isolates, were able to significantly reduce levels of disease. This study highlights the potential of plants pre-colonised with T. atrobrunneum for effective protection against A. mellea in two hosts from different plant families

On observation of dispersion in tunable second-order nonlinearities of silicon-rich nitride thin films

We present experimental results on second-harmonic generation in non-stoichiometric, silicon-rich nitride (SRN) films. The as-deposited film presents a second-order nonlinear coefficient, or \c{hi}(2), as high as 8pm/V. This value can be widely tuned using the electric field induced second harmonic effect (EFISH), and a maximum value of 22.7pm/V was achieved with this technique. We further illustrate that the second-order nonlinear coefficient exhibited by these films can be highly dispersive in nature, and requires further study and analysis to evaluate their viability for in-waveguide applications at telecommunication wavelengths

Prospects for Gene lntrogression from Hordeum bulbosum L. into Barley (H. vulgare L.).

Hybridizations between Hordeum vulgare L. (cultivated barley) and H. bulbosum L. have been performed over many years with two aims. First, the production of doubled haploid barley cultivars (Kasha and Kao 1970); second, the transfer of desirable traits such as resistance to fungal and viral pathogens from the wild species into barley. Apart from the report of an occasional recombinant (Xu and Kasha 1992; Pickering et al 1994), successful gene introgression has been hampered by several barriers. In this report we will describe recent progress in overcoming these barriers