Shading Samples Research Articles

A comparative evaluation of physical properties of CAD/CAM complete denture resins- an in vitro study

BackgroundIn dentistry, there is a growing preference for computer-aided design and computer-aided manufacturing (CAD/CAM) systems over traditional laboratory procedures. However, there is not much literature comparing various CAD/CAM materials. Thus, this study aimed to assess and compare the color stability and hardness of gingival and tooth colored milled and 3D-printed acrylic resins.Materials and methodsFour types of CAD/CAM materials were prepared: 3D-printed pink shade (PP), milled polymenthymethacrylate (PMMA) pink shade (MP), 3D-printed tooth shade (PT) and milled PMMA tooth shade (MT) (n = 6). For hardness, disc shaped samples of 15 mm × 2 mm and for color stability, bar shaped samples of 65mmx10mmx2.5 mm were prepared and polished. Vickers hardness test was performed in a microhardness tester. Color stability test was done by immersing in coffee solution and coca cola for 7 days. Day 0 and day 7 measurements were recorded using a digital spectrophotometer and the change in color was calculated. For statistical analysis, one-way ANOVA and Tukey’s post hoc tests were done.ResultsFor color stability, milled PMMA was superior to 3D-printed resin samples. Milled pink and tooth shade samples had similar color stability, whereas 3D-printed tooth shade samples were more color stable as compared to pink shade 3D-printed samples. For hardness, milled tooth shade PMMA was the most superior one, followed by 3D-printed tooth shade, whereas pink shade milled PMMA and 3D-printed resin samples had similar hardness values and were inferior to the tooth shade CAD/CAM materials.ConclusionColor stability of milled PMMA is superior to that of 3D-printed resins. Hardness of tooth shade milled and 3D-printed resins is more than that of pink shade milled and 3D-printed resins.

Real-time Realistic Volume Rendering of Consistently High Quality with Dynamic Illumination.

Direct Volume Rendering (DVR) plays an important role in scientific data visualization. To generate photo-realistic DVR results, the physical light transport throughout the volume is simulated by applying the Monte Carlo-based volumetric path tracing (VPT) approach. For real-time applications, due to the time constraint for rendering each frame, only a limited number of samples shall be taken for the computation per pixel. This can result in a significant amount of noise in the rendering results. This paper describes our optimized VPT sampling algorithm and a novel denoising technique to generate consistently high-quality realistic DVR results in real time. We develop a new shading model that can reduce estimation variance to enhance the quality of DVR results. Additionally, a hybrid acceleration structure is created by integrating both octree and macrocell to improve sampling efficiency. This allows the acquisition of sufficiently more shading samples while maintaining the desired interactive frame rate. To further eliminate remaining noise and improve temporal stability of DVR results, we develop a novel spatiotemporal denoising framework. Our denoiser decouples the estimated radiance into high-detail low-noise and low-detail high-noise components. Different denoising algorithms are separately applied to these components to reduce noise without introducing blurring artifacts. Our DVR system can consistently offer high rendering quality and good temporal stability across DVR result frames in real time. During fast user interactions and with rapid alterations of the illumination condition, our rendering method can still provide good visual comfort and representation accuracy without visible latency.

Fifteen ceramic gingival samples: A proposed gingival shade guide

Objective(1) To put forward a set of valid pink ceramic samples for subjective gingival colour selection in the Caucasian population, and (2) to assess the quality of the shade matches provided by the selected pink samples. MethodsThe ceramic gingival shade samples (n = 133) were obtained by mixing pairs of basic colours from a single system. In each mixture, the proportions of the colours were altered in 10% increments, following the numerical order used by the manufacturers of the three colour systems under study (Heraceram, Vita VM9 and IPS Style). The CIELAB colour coordinates were recorded using spectrophotometry in three zones of healthy anterior gingiva (n = 360). The sample was randomly divided into two subsamples, each of which contained 180 participants. Subsample 1 was used to select the ceramic gingival samples that provided the best shade matches, using the k-means clustering method. Subsample 2 was used to assess the chromatic validity of the selected gingival samples, according to the coverage error. ResultsTo identify the ceramic gingival samples that best represented participants’ gingival colour, the minimum colour differences (ΔEab∗, ΔE00) between the cluster centroids and the 133 gingival samples were calculated. Fifteen gingival samples were selected: 8 from the Heraceram system, 4 from the VM9 system, and 3 from the IPS Style system. Coverage errors for the 15 gingival samples fell below the gingival clinical acceptability thresholds in the three gingival zones examined. ConclusionsThe 15 ceramic gingival colour samples provide satisfactory coverage of the gingival colour space, with coverage errors below the ΔE00 clinical acceptability threshold of 2.9 units. These pink colour samples have the potential to provide good gingival shade matches in subjective colour selection. Clinical SignificanceMixing basic ceramic colours is a viable method for generating a series of pink shades that can be used as a physical gingival shade guide. The resulting guide provides valid results (under the acceptability thresholds) for subjective selection gingival colour selection in clinical practice.

EFFECT OF DIFFERENT DRYING METHODS ON THE NUTRITIONAL AND SENSORY ATTRIBUTES OF ABELMOSCHUS ESCULENTUS (OKRA)

This work was carried out to study the effect of different drying methods (shade, oven and sun drying) on the nutritional and sensory properties of Abelmoschus esculentus (okra vegetable). Results from this study showed that the carbohydrate content ranged from 11.64% in sample A to 54.20% in sample D, an increase due to the removal of moisture. The crude fat ranged from 0.52% to 3.40%. The ash content was markedly enhanced by drying too and it ranged from 1.30% in fresh sample to 8.91% in shade-dried sample, the fibre content ranged from 1.12% in fresh sample to 16.43 % in sun-dried sample. A slight decrease in mineral content was observed upon drying except sodium and magnesium which was found to be significantly higher in the fresh sample. There were increase in phosphorous and potassium upon drying. The vitamin content showed significant difference (p<0.05) in the level of vitamin C, it ranged from 3.68 mg/kg to 1.41mg/kg, the fresh sample ranked higher followed by shade, oven and sun-dried samples. The result for sensory quality attributes showed significance difference (p<0.05) in all the attributes of the okra soup made from the samples and shade dried sample gave the best result in terms of colour and taste which maybe low temperature processing that retained its sensory qualities. The result of this study suggests that drying improved the concentration of nutrients and could be useful in preserving Abelmoschus esculentus in a good way and ensure its availability all year round

SnakeBinning: Efficient Temporally Coherent Triangle Packing for Shading Streaming

AbstractStreaming rendering, e.g., rendering in the cloud and streaming via a mobile connection, suffers from increased latency and unreliable connections. High quality framerate upsampling can hide these issues, especially when capturing shading into an atlas and transmitting it alongside geometric information. The captured shading information must consider triangle footprints and temporal stability to ensure efficient video encoding. Previous approaches only consider either temporal stability or sample distributions, but none focuses on both. With SnakeBinning, we present an efficient triangle packing approach that adjusts sample distributions and caters for temporal coherence. Using a multi‐dimensional binning approach, we enforce tight packing among triangles while creating optimal sample distributions. Our binning is built on top of hardware supported real‐time rendering where bins are mapped to individual pixels in a virtual framebuffer. Fragment shader interlock and atomic operations enforce global ordering of triangles within each bin, and thus temporal coherence according to the primitive order is achieved. Resampling the bin distribution guarantees high occupancy among all bins and a dense atlas packing. Shading samples are directly captured into the atlas using a rasterization pass, adjusting samples for perspective effects and creating a tight packing. Comparison to previous atlas packing approaches shows that our approach is faster than previous work and achieves the best sample distributions while maintaining temporal coherence. In this way, SnakeBinning achieves the highest rendering quality under equal atlas memory requirements. At the same time, its temporal coherence ensures that we require equal or less bandwidth than previous state‐of‐the‐art. As SnakeBinning outperforms previous approach in all relevant aspects, it is the preferred choice for texture‐based streaming rendering.

Assessment of PowerPlex® Fusion 5C’s ability to type degraded DNA

DNA samples collected at crime scenes are often degraded so this research focused on the ability of the Promega PowerPlex® Fusion 5C amplification kit to type both naturally and artificially degraded DNA.DNA was degraded naturally by placing equal volumes of blood on white fabric that was stored either inside, outside in a shaded area, or outside in direct sunlight. Samples were then collected every 10 days for 60 days and the DNA extracted (QIAamp® DNA Investigator). Artificially degraded samples were created by exposing extracted DNA to either UV light or 95 °C heat for varying times. DNA was also degraded artificially by placing blood samples into a 50% bleach solution for varying times prior to extraction.Following sample treatment, standard forensic DNA analysis was performed including quantification (Investigator® Quantiplex) and amplification (PowerPlex® Fusion 5C). Separation and detection were performed on an ABI 3130xl capillary electrophoresis unit and analysis was performed using GeneMapper ID v3.2.1.While the time and shade samples showed similar amounts of degradation, the samples exposed to direct sun showed more degradation. The artificially degraded samples showed more signs of degradation such as reduced overall peak height and peak height imbalance at heterozygous loci. There were also some cases where an allele that was known to be in the profile exhibited total dropout. Although there were some instances of both allelic dropout and heterozygote peak imbalance, PowerPlex® Fusion was able to reliably type degraded DNA as all alleles detected were consistent with the known donor profile. The results show that PowerPlex® Fusion is a robust kit capable of handling forensically challenged samples.

The effect of different shading net on the Quantum Efficiency of PS II in chilli pepper cultivar ‘Star Flame’

The study was undertaken to identify the effect of different shading net on the quantum efficiency of PS II on ‘Star Flame’ chilli pepper (Capsicum annuum) over a period of time cultivated under plastic house environment. ‘Star Flame’ pepper was grown under red shading net and samples without shading were used as control. Analysis of photosynthetic activity revealed a significant difference (p<0.05) between Fv/Fm values in control and red shading at the end of July (p = 0.031) after the first harvest. Chlorophyll fluorescence parameter Fv/Fm reflects the maximum quantum efficiency of photosystem II (PS II) used in the detection of early stress in plants.

The effect of temperature and light on strawberry production in a solar greenhouse

Strawberry production is greatly affected by environmental factors, especially temperature and light. A solar greenhouse with opaque photovoltaic (OPV) modules and a solar combined air source heat pump system was built for strawberry production. The aim of this study was to assess the impact of differences in both temperature and light factors caused by OPV modules and solar heating on strawberry growth and quality in a constructed greenhouse. The ‘Jingzangxiang’ strawberry was selected and planted in the greenhouse. The indoor temperature with the heating system was 5.3–7.3 °C higher than the ambient temperature at the coldest period in the city of Kunming. At noon, the chlorophyll content of the shaded strawberry plants was 1.3 times higher than that of the unshaded plants in sunny weather, and the average shaded photosynthetically active radiation (PAR) was 230 μmol·m−2·s−1 in the greenhouse, where 25.9% of the roof was covered with OPV modules. Under this shading treatment, the optimum light range of PAR for the ‘Jingzangxiang’ strawberry was 387–437 μmol·m−2·s−1, and the optimum temperature range during the daytime was 20.5–27.4 °C. The largest single strawberry fruit weighed 33.9 g, and the soluble solids content of the shaded strawberry fruit was 16.4%, which was higher than that of the unshaded strawberry samples. Furthermore, the yield of the shaded samples was 1.2 times that of the unshaded samples. In summary, strawberry plants shaded by OPV modules were superior to unshaded strawberry plants in terms of growth, quality and yield. This research provides experimental support and information on the optimal temperature and light ranges for the growth of the ‘Jingzangxiang’ strawberry in solar greenhouse.

Tessellated Shading Streaming

AbstractPresenting high‐fidelity 3D content on compact portable devices with low computational power is challenging. Smartphones, tablets and head‐mounted displays (HMDs) suffer from thermal and battery‐life constraints and thus cannot match the render quality of desktop PCs and laptops. Streaming rendering enables to show high‐quality content but can suffer from potentially high latency. We propose an approach to efficiently capture shading samples in object space and packing them into a texture. Streaming this texture to the client, we support temporal frame up‐sampling with high fidelity, low latency and high mobility. We introduce two novel sample distribution strategies and a novel triangle representation in the shading atlas space. Since such a system requires dynamic parallelism, we propose an implementation exploiting the power of hardware‐accelerated tessellation stages. Our approach allows fast de‐coding and rendering of extrapolated views on a client device by using hardware‐accelerated interpolation between shading samples and a set of potentially visible geometry. A comparison to existing shading methods shows that our sample distributions allow better client shading quality than previous atlas streaming approaches and outperforms image‐based methods in all relevant aspects.

Qualitative and Quantitative Phytochemical Analysis and Antioxidant Properties of Leaves and Stems of Clinacanthus nutans (Burm. f.) Lindau from Two Herbal Farms of Negeri Sembilan, Malaysia

The objective of the study is to analyse the phytochemical content by quantitative and qualitative methods and to investigate the antioxidant properties on Clinacanthus nutans leaves and stems from different areas: Yik Poh Ling (YPL) un-shaded sample (exposed to direct sunlight) and You Dun Chao (YDC) un-shaded and shaded (with black shade netting) samples. Extracts were prepared by dissolving fine powder of C. nutans in 1:10 solvent using ultrasonic extraction for an hour. Preliminary screening and quantitative estimation of phytochemical (alkaloids, flavonoids, cardiac glycosides, saponins, steroids, terpenoids, phenols and tannins) analysis were conducted. Then, determination of antioxidant properties (total phenolic content, TPC, ferric reducing/ antioxidant power, FRAP and radical-scavenging activities, DPPH) were conducted. All the samples contained alkaloids, flavonoids, cardiac glycosides, saponins, steroids, terpenoids, phenols and tannins. Un-shaded leaves of C. nutans from YDC exhibited significantly higher result in antioxidant properties (966.00mg GAE/g of dried sample in TPC, 20.44mg TE/g of dried sample in FRAP and 11.14mg TE/g of dried sample in DPPH) than the other samples (p < 0.05). As a conclusion, C. nutans has a good potential to be an alternative antioxidant source.

Foveated Depth-of-Field Filtering in Head-Mounted Displays

In recent years, a variety of methods have been introduced to exploit the decrease in visual acuity of peripheral vision, known as foveated rendering. As more and more computationally involved shading is requested and display resolutions increase, maintaining low latencies is challenging when rendering in a virtual reality context. Here, foveated rendering is a promising approach for reducing the number of shaded samples. However, besides the reduction of the visual acuity, the eye is an optical system, filtering radiance through lenses. The lenses create depth-of-field (DoF) effects when accommodated to objects at varying distances. The central idea of this article is to exploit these effects as a filtering method to conceal rendering artifacts. To showcase the potential of such filters, we present a foveated rendering system, tightly integrated with a gaze-contingent DoF filter. Besides presenting benchmarks of the DoF and rendering pipeline, we carried out a perceptual study, showing that rendering quality is rated almost on par with full rendering when using DoF in our foveated mode, while shaded samples are reduced by more than 69%.

Gradient Estimation for Real-time Adaptive Temporal Filtering

With the push towards physically based rendering, stochastic sampling of shading, e.g. using path tracing, is becoming increasingly important in real-time rendering. To achieve high performance, only low sample counts are viable, which necessitates the use of sophisticated reconstruction filters. Recent research on such filters has shown dramatic improvements in both quality and performance. They exploit the coherence of consecutive frames by reusing temporal information to achieve stable, denoised results. However, existing temporal filters often create objectionable artifacts such as ghosting and lag. We propose a novel temporal filter which analyzes the signal over time to derive adaptive temporal accumulation factors per pixel. It repurposes a subset of the shading budget to sparsely sample and reconstruct the temporal gradient. This allows us to reliably detect sudden changes of the sampled signal and to drop stale history information. We create gradient samples through forward-projection of surface samples from the previous frame into the current frame and by reevaluating the shading samples using the same random sequence. We apply our filter to improve real-time path tracers. Compared to previous work, we show a significant reduction of lag and ghosting as well as improved temporal stability. Our temporal filter runs in 2 ms at 1080p on modern graphics hardware and can be integrated into deferred renderers.

Seasonal variation of δ18O and δ2H in leaf water of Fagus sylvatica L. and related water compartments

The study aims to assess variability in leaf water isotopic enrichment occurring in the field under natural conditions. We focused on seasonal variation and difference between sun-exposed and shaded leaves. Isotopic composition (δ18O, δ2H) of leaf water was monitored in a beech tree (Fagus sylvatica L.) growing in the forest-meadow ecotone together with δ18O (2H) of water compartments which are in close relation to this signal, namely twig and soil water. The sampling was carried out in approximately two-week intervals during five consecutive vegetation seasons.The δ18O (2H) data showed a distinct seasonal pattern and a consistency in relative differences between the seasons and sample categories. Leaf water was the most isotopically enriched water compartment. The leaf water enrichment decreased toward the autumn reflecting the change in δ18O (2H) of source water and evaporative demands. The soil and twig water isotopic signal was depleted against current precipitation as it partly retained the isotopic signature from winter precipitation however the seasonal pattern of soil and twig water followed that of precipitation. No significant differences between sun-exposed and shaded samples were detected. Nevertheless, the observed strong seasonal pattern of isotope composition of leaf, twig and soil water should be taken into account when using leaf water enrichment for further calculations or modeling.

Fast shading correction for cone beam CT in radiation therapy via sparse sampling on planning CT.

The image quality of cone beam computed tomography (CBCT) is limited by severe shading artifacts, hindering its quantitative applications in radiation therapy. In this work, we propose an image-domain shading correction method using planning CT (pCT) as prior information which is highly adaptive to clinical environment. We propose to perform shading correction via sparse sampling on pCT. The method starts with a coarse mapping between the first-pass CBCT images obtained from the Varian TrueBeam system and the pCT. The scatter correction method embedded in the Varian commercial software removes some image errors but the CBCT images still contain severe shading artifacts. The difference images between the mapped pCT and the CBCT are considered as shading errors, but only sparse shading samples are selected for correction using empirical constraints to avoid carrying over false information from pCT. A Fourier-Transform-based technique, referred to as local filtration, is proposed to efficiently process the sparse data for effective shading correction. The performance of the proposed method is evaluated on one anthropomorphic pelvis phantom and 17 patients, who were scheduled for radiation therapy. (The codes of the proposed method and sample data can be downloaded from https://sites.google.com/view/linxicbct) RESULTS: The proposed shading correction substantially improves the CBCT image quality on both the phantom and the patients to a level close to that of the pCT images. On the phantom, the spatial nonuniformity (SNU) difference between CBCT and pCT is reduced from 74 to 1HU. The root of mean square difference of SNU between CBCT and pCT is reduced from 83 to 10HU on the pelvis patients, and from 101 to 12HU on the thorax patients. The robustness of the proposed shading correction is fully investigated with simulated registration errors between CBCT and pCT on the phantom and mis-registration on patients. The sparse sampling scheme of our method successfully avoids false structures in the corrected CBCT even when the maximum registration error is as high as 8mm. We develop an effective shading correction algorithm for CBCT readily implementable on clinical data as a software plug-in without modifications of current imaging hardware and protocol. The algorithm is directly applied on the output images from a commercial CBCT scanner with high computational efficiency and negligible memory burden.

Infrared spectral evidence and DFT calculations of hydrogen-bonding and molecular structures of acetogenins

FTIR spectra have been measured for 31 different five component - simplex centroid design solvent mixture extracts of shaded and sun-exposed Annonaceous leaves harvested in all four seasons. The spectral frequencies are characteristic of anonnaceous acetogenins known to be a major component of these leaves. OH stretching spectral bands in the 3100-3600 cm−1 region provide evidence of notable intensity changes for the shaded and sun-exposed leaves. Chemometric principal component analysis involving 264 spectra show that shaded samples tend to have more intense OH stretching bands than those grown in the sun. B3LYP density functional calculations indicate significant OH stretching band changes in this region owing to hydrogen bond formation. Weak OH intensity enhancements, around 40 km mol−1, occur when an OH group forms a hydrogen bond with the oxygen atom of an adjacent tetrahydrofuran ring oxygen atom. Much more intense enhancements, 400–500 km mol−1, are predicted to occur for acetogenins with two tetrahydrofuran rings for which the OH group hydrogen bonds with its fartherest removed tetrahydrofuran ring oxygen. Whereas weak or moderate H-bond stretching intensities are obtained for acetogenins with slightly bent carbon chain structures the strongest hydrogen bond intensities are calculated for molecules with a 45° V-type backbone structure. These important structural modifications as well as significant changes in bond lengths and angles owing to hydrogen bonding are detailed.

Objective evaluation of singeing efficiency by digital image processing

An objective and reliable evaluation method for the efficiency of singeing process is developed by use of digital image processing. The overall fabric surface roughness before and after the singeing process has been estimated and evaluated comprehensively, specifically experimenting for darker shade samples that are prone to visual inspection errors. The energy, entropy, inertia, and homogeneity parameters of images of the fabric after and before singeing have been identified as the suitable descriptors of fabric surface roughness. A new integrating sphere imaging system that has been designed indigenously was used for image capture and analysis of unsinged and singed fabric with a digital DSLR camera. The imaging system ensures controlled, diffused and uniform illumination across the samples. The proposed evaluation method is found to be suitable and economic for analysis of singeing efficiency.

The effects of preharvest shading and postharvest storage temperatures on the quality of ‘Ponkan’ (Citrus reticulata Blanco) mandarin fruits

A two-year trial was performed to investigate the effects of using preharvest white shade nets and postharvest storage at 13.5°C or 25°C on the physiological responses and quality of ‘Ponkan’ mandarin fruits. A significant reduction in leaf and fruit surface temperatures, PPF, and sunburn was seen when using white shade nets in comparison with the control sample. Trees grown under white netting had a significantly higher juice percentage, less weight loss, lower granulation percentage, and lower percentage decay than the control sample. However, there were no significant differences in peel color, total soluble solids (TSS), and titratable acid (TA) between the control and shading samples after postharvest storage at 13.5°C or 25°C. In summary, ‘Ponkan’ mandarin grown with white shading nets exhibited greater sunscald resistance, higher juice percentage, and less weight loss and granulation when stored at 13.5°C postharvest than the mandarin grown without shading and those stored at 25°C.

Deep shading buffers on commodity GPUs

Real-time rendering with true motion and defocus blur remains an elusive goal for application developers. In recent years, substantial progress has been made in the areas of rasterization, shading, and reconstruction for stochastic rendering. However, we have yet to see an efficient method for decoupled sampling that can be implemented on current or near-future graphics processors. In this paper, we propose one such algorithm that leverages the capability of modern GPUs to perform unordered memory accesses from within shaders. Our algorithm builds per-pixel primitive lists in canonical shading space. All shading then takes place in a single, non-multisampled forward rendering pass using conservative rasterization. This pass exploits the rasterization and shading hardware to perform shading very efficiently, and only samples that are visible in the final image are shaded. Last, the shading samples are gathered and filtered to create the final image. The input to our algorithm can be generated using a variety of methods, of which we show examples of interactive stochastic and interleaved rasterization, as well as ray tracing.

Sub‐Pixel Anti‐Aliasing Via Triangle‐Based Geometry Reconstruction

AbstractAnti‐aliasing has recently been employed as a post‐processing step to adapt to the deferred shading technique in real‐time applications. Some of these existing algorithms store supersampling geometric information as geometric buffer (G‐buffer) to detect and alleviate sub‐pixel‐level aliasing artifacts. However, the anti‐aliasing filter based on sampled sub‐pixel geometries only may introduce unfaithful shading information to the sub‐pixel color in uniform‐geometry regions, and large G‐buffer will increase memory storage and fetch overheads. In this paper, we present a new Triangle‐based Geometry Anti‐Aliasing (TGAA) algorithm, to address these problems. The coverage triangle of each screen pixel is accessed, and then, the coverage information between the triangle and neighboring sub‐pixels is stored in a screen‐resolution bitmask, which allows the geometric information to be stored and accessed in an inexpensive manner. Using triangle‐based geometry, TGAA can exclude irrelevant neighboring shading samples and achieve faithful anti‐aliasing filtering. In addition, a morphological method of estimating the geometric edges in high‐frequency geometry is incorporated into the TGAA's anti‐aliasing filter to complement the algorithm. The implementation results demonstrate that the algorithm is efficient and scalable for generating high‐quality anti‐aliased images.

Environmental Survival of Mycobacterium avium subsp. paratuberculosis in Different Climatic Zones of Eastern Australia

The duration of survival of both the S and C strains of Mycobacterium avium subsp. paratuberculosis in feces was quantified in contrasting climatic zones of New South Wales, Australia, and detailed environmental temperature data were collected. Known concentrations of S and C strains in feces placed on soil in polystyrene boxes were exposed to the environment with or without the provision of shade (70%) at Bathurst, Armidale, Condobolin, and Broken Hill, and subsamples taken every 2 weeks were cultured for the presence of M. avium subsp. paratuberculosis. The duration of survival ranged from a minimum of 1 week to a maximum of 16 weeks, and the provision of 70% shade was the most important factor in extending the survival time. The hazard of death for exposed compared to shaded samples was 20 and 9 times higher for the S and C strains, respectively. Site did not affect the survival of the C strain, but for the S strain, the hazard of death was 2.3 times higher at the two arid zone sites (Broken Hill and Condobolin) than at the two temperate zone sites (Bathurst and Armidale). Temperature measurements revealed maximum temperatures exceeding 60°C and large daily temperature ranges at the soil surface, particularly in exposed boxes.