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We present a general framework for dealing with set heterogeneity in data and learning problems, which is able to exploit low complexity components. The main ingredients are (i) A definition of complexity for elements of a convex union that takes into account the complexities of their individual composition – this is used to cover the heterogeneous convex union; and (ii) Upper bounds on the complexities of restricted subsets. We demonstrate this approach in two different application areas, highlighting their conceptual connection. (1) In random projection based dimensionality reduction, we obtain improved bounds on the uniform preservation of Euclidean norms and distances when low complexity components are present in the union. (2) In statistical learning, our generalisation bounds justify heterogeneous ensemble learning methods that were incompletely understood before. We exemplify empirical results with boosting type random subspace and random projection ensembles that implement our bounds.

BACKGROUND There is very little research on the cognitive profile of young children with Williams syndrome (WS). METHOD The present study utilised the Differential Ability Scales - Second Edition to examine the early cognitive abilities of 22 young children with WS (aged 3.98 to 7.70 years, 10 male and 12 female participants). RESULTS Overall, IQ ranged from 38 (severely impaired) to 81.00 (low average). Consistent with Mervis et al. who looked at an older sample, over half (59.08%) of our young WS sample showed a significant and abnormal weakness in spatial ability relative to verbal ability. Moreover, 81.82% showed a significant and clinically unusual weakness in spatial ability relative to nonverbal reasoning ability. At the subtest level, only 4.55% of our sample showed a significant strength in naming vocabulary compared with verbal comprehension, while 13.64% showed a significant weakness in naming vocabulary relative to verbal comprehension. CONCLUSIONS The results of the present study show cognitive heterogeneity, consistent with the literature on older children and adults with WS. There were variable levels of intellect and variable patterns of cognitive strength and weakness across both index and subtest scores. Findings highlight the need for individual assessment and management of young children with WS but also indicate that for the majority of WS individuals spatial skills are indeed an area of significant and abnormal weakness and should be a focus for early intervention.

It is increasingly recognised that when healthcare staff fails to give adequate credence to patients' illness-related knowledge work, this epistemic injustice undermines person-centred care. Therefore, we set out to examine the experiences of people with long-term conditions with knowledge work in healthcare settings to identify changes needed to strengthen person-centred primary care.We designed a qualitative study and recruited people with long-term conditions in the UK. We conducted individual interviews (analysed using interpretive phenomenological analysis) and focus groups (analysed using thematic analysis), then integrated findings from both methods through an approach focused on their complementarity.Participants described how successful person-centred consultations were characterised by a negotiation between patient and doctor and moments of broad exploration, reflexive listening, and reciprocal enquiry, which allowed for epistemic reciprocity.Epistemic reciprocity is a core component of person-centred clinical consultations, fostering the co-creation of new knowledge of patient experience and need through the interactive knowledge work of patient and doctor.Medical education could benefit from initiatives that develop knowledge use and integration skills across primary care professionals. Accommodating for patient's and doctor's knowledge work during clinical practice requires redesigning the consultation process, including timing, headspace, pre-consultation, and post-consultation work.

Introduction AEC (Ambulatory Emergency Care) provides acute assessment and treatment in the community for acutely unwell complex older patients, with patients staying in their own homes overnight. This investigation aimed to understand the impact of the AEC Setting on Clinical Decision-Making. Method Three AEC sites were purposively sampled to recruit twelve clinicians with backgrounds in Geriatrics, General Practice, Emergency and Acute Medicine. This qualitative investigation used focused ethnography within a case study approach to understand the decision-making processes in the context of the AEC environment. Observation during an AEC shift was complemented by informant interviews. A framework approach to thematic analysis used ‘a priori’ and data derived codes to develop explanatory themes. Constant comparison and cognitive task analysis were used to evaluate the clinicians’ decision-making processes for index patient cases. Results Across-case analysis of the experience and training of the AEC clinicians identified that the main similarity in training was having a varied background experience. These ‘hybrid physicians’ were able to work across professional boundaries and considered their diversity of training a strength. The AEC clinicians had considerable contextual awareness of their environment and how this differed from their routine clinical practice. The participants felt that AEC working altered their thresholds for concern and increased their community orientation. Conclusion This critical example demonstrates the importance of diversity of background training and community orientation when considering alternatives to acute hospitalisation for unwell older adults. As more interventions such as the Urgent Community Response are implemented across the UK, further training is needed to ensure that AEC clinicians obtain a broad spectrum of practice. Future research is needed to investigate optimal team and skill mix in AEC.

We consider a large number of agents collaborating on a multi-armed bandit problem with a large number of arms. The goal is to minimise the regret of each agent in a communication-constrained setting. We present a decentralised algorithm which builds upon and improves the Gossip-Insert-Eliminate method of Chawla et al. (International conference on artificial intelligence and statistics, pp 3471–3481, 2020). We provide a theoretical analysis of the regret incurred which shows that our algorithm is asymptotically optimal. In fact, our regret guarantee matches the asymptotically optimal rate achievable in the full communication setting. Finally, we present empirical results which support our conclusions.

In order to identify CT signs that could be used to distinguish cranial mediastinal lymphoma and thymic epithelial neoplasia, a retrospective case-control study was done. Associations between CT signs and diagnosis were tested using binary logistic regression and results expressed as odds ratio and 95% confidence interval. Sixty-two dogs that had thoracic CT and confirmed diagnosis of lymphoma (n = 33) or thymic neoplasia (n = 29) were sampled. Thymic neoplasms included 24 thymomas and five thymic carcinomas. Dogs with thymic epithelial neoplasia were significantly older than dogs with lymphoma (median age 8.6 years versus 6.0 years, P = .007), but there were no significant differences in prevalence of clinical signs. Diagnosis of thymic epithelial neoplasia was associated with heterogeneous attenuation in pre- (odds ratio 23.3, 95% confidence interval, 4.5-121.1) and post-contrast (odds ratio 30.7, 95% confidence interval, 3.6-265.0) images. Conversely, envelopment of the cranial vena cava by the mass was less likely with thymic epithelial neoplasia than lymphoma (odds ratio 0.07, 95% confidence interval, 0.007-0.66). Greater standard deviation of Hounsfield unit values in post-contrast images was associated with thymic epithelial neoplasia (P = .005). Based on ROC analysis, SD > 17HU of the mass in post-contrast images had a sensitivity of 72% and specificity of 79% for thymic epithelial neoplasia. There were no significant differences in morphology, prevalence of calcification, mediastinal lymphadenopathy, cranial vena cava invasion, collateral vessels, or pleural fluid associated with these tumors. Thymic epithelial neoplasms tended to occur in older dogs and were heterogeneous in CT images, whereas mediastinal lymphoma was more homogeneous and more likely to envelop the cranial vena cava.

End-to-End training (E2E) is becoming more and more popular to train complex Deep Network architectures. An interesting question is whether this trend will continue—are there any clear failure cases for E2E training? We study this question in depth, for the specific case of E2E training an ensemble of networks. Our strategy is to blend the gradient smoothly in between two extremes: from independent training of the networks, up to to full E2E training. We find clear failure cases, where overparameterized models cannot be trained E2E. A surprising result is that the optimum can sometimes lie in between the two, neither an ensemble or an E2E system. The work also uncovers links to Dropout, and raises questions around the nature of ensemble diversity and multi-branch networks.

The application of aerobic granular sludge (AGS) technology has increased in popularity, largely due to the smaller physical footprint, enhanced biological nutrient removal performance and ability to perform with a more stable operation when compared to conventional activated sludge (CAS) systems. To date,the ability of AGS to remove microbial pathogens such as; Escherichia coli, Giardia, and Cryptosporidium has not been reported. This study compared the log₁₀ removal performance of commonly used pathogen surrogates (sulfite-reducing clostridia spores, f-RNA bacteriophage, E. coli and total coliforms) by AGS and CAS during the start-up phase, through to maturation. Results showed that AGS performed as well as CAS for the log₁₀ removal performance of all microbial surrogates, except for spores which were removed more effectively by AGS most likely due to greater adherence of spores to the AGS biomass compared to CAS mixed liquor. Results suggest that AGS is capable of meeting or exceeding CAS-equivalent health based targets for pathogen removal in the context of water recycling as well as not adversely affecting the secondary effluent water quality (suspended solids, turbidity and particle size) in terms of ultraviolet light transmissivity (254 nm). These findings confirmed for the first time that the adoption of AGS operation would not adversely impact downstream tertiary disinfection processes from altered water quality, nor would it require further pathogen treatment interventions in addition to what is already required for CAS systems. Refereed/Peer-reviewed

The objective of this review is to highlight the need for further investigation of microbial toxicity caused by desorption of surfactant from Surfactant Modified Zeolite (SMZ). SMZ is a low cost, versatile permeable reactive media which has the potential to treat multiple classes of contaminants. With this combination of characteristics, SMZ has significant potential to enhance water and wastewater treatment processes. Surfactant desorption has been identified as a potential issue for the ongoing usability of SMZ. Few studies have investigated the toxicity of surfactants used in zeolite modification towards microorganisms and fewer have drawn linkages between surfactant desorption and surfactant toxicity. This review provides an overview of natural zeolite chemistry, characteristics and practical applications. The chemistry of commonly used surfactants is outlined, along with the kinetics that drive their adsorption to the zeolite surface. Methodologies to characterise this surfactant loading are also described. Applications of SMZ in water remediation are highlighted, giving focus to applications which deal with biological pollutants and where microorganisms play a role in the remediation process. Studies that have identified surfactant desorption from SMZ are outlined. Finally, the toxicity of a commonly used cationic surfactant towards microorganisms is discussed. This review highlights the potential for surfactant to desorb from the zeolite surface and the need for further research into the toxicity of this desorbed surfactant towards microorganisms, including pathogens and environmental microbes.

Surfactant Modified Zeolite (SMZ) represents a versatile, cost-effective permeable reactive material, capable of treating multiple classes of contaminants. The potential for HDTMA-Br, a cationic surfactant commonly used to modify zeolite, to desorb from the zeolite surface has been identified as a potential issue for the ongoing use of SMZ in water remediation contexts. This paper investigates the toxicity of HDTMA-Br towards enteric virus surrogates, F-RNA bacteriophage MS2 and E. coli, Bacillus subtilis, and soil microflora. The concentration of surfactant desorbing from SMZ was quantified through a bioassay using E. coli. Results showed HDTMA-Br concentrations of ≥10-5M were toxic to MS2, ≥10-4M were toxic to E. coli and ≥10-6M were toxic to B. subtilis. No toxic relationship was established between HDTMA-Br and soil microflora. Desorption of ≥10-4M of HDTMA-Br was shown for the two SMZ samples under the mixing conditions used. Effects of this surfactant on total soil microflora were ambiguous since no toxic relationship could be established, however, HDTMA-Br, at concentrations desorbing from SMZ, were shown to impact the soil bacterium B. subtilis. Further research is required to determine the effect of this surfactant on microbial populations and species diversity in soils.

Objectives To report the prevalence of abnormal fluoroscopic findings in brachycephalic dogs that were presented to a referral hospital for obstructive airway syndrome. Methods Hospital records between May 2013 and November 2015 identified 36 brachycephalic dogs investigated for obstructive airway disease: 21 French bulldogs, 6 bulldogs, 4 Boston terriers, 2 pugs, 2 boxers and 1 shih-tzu. The presence or absence of hiatal hernia, delayed oesophageal transit, gastro-oesophageal reflux and redundant oesophagus were recorded. Results Of the 36 dogs, 16 had hiatal hernia, all of which were French bulldogs; 31 dogs had delayed oesophageal transit time, 27 had gastro-oesophageal reflux, and 4 had redundant oesophagus. Clinical Significance Clinical Significance: The prevalence of hiatal hernia is higher than expected in the French bulldog, and there was a high prevalence of oesophageal disease in this group in general. These results suggest a need to investigate similar cases for evidence of gastrointestinal disease that may also require attention.

Modern applications of machine learning typically require the tuning of a multitude of hyperparameters. With this motivation in mind, we consider the problem of optimization given a set of noisy function evaluations. We focus on robust optimization in which the goal is to find a point in the input space such that the function remains high when perturbed by an adversary within a given radius. Here we identify the minimax optimal rate for this problem, which turns out to be of order [Formula: see text], where [Formula: see text] is the sample size and [Formula: see text] quantifies the smoothness of the function for a broad class of problems, including situations where the metric space is unbounded. The optimal rate is achieved (up to logarithmic factors) by a conceptually simple algorithm based on [Formula: see text]-nearest neighbor regression.

Aerobic granular sludge can improve the efficacy of wastewater treatment in existing sequencing batch reactors (SBRs) compared to conventional floccular sludge. Despite the well known advantages of increased capacity, reduced reactor footprint and enhanced nutrient removal, many performance characteristics of granular and floccular sludges have not been directly compared, in particular for sludges generated from treating the same sewage source. In this study we investigated the microstructure, microbial composition, settling and dewatering properties of granular and floccular sludge generated from the same sewage sources. Cryo-scanning electron microscopy analysis indicated that the granular and floccular sludges had a significantly different internal network structure, with flocs being much more open and porous than granules. Sulphur deposits were clearly visible on the surfaces of granules, which was complemented by the enrichment of some sulphur oxidising bacterial species compared to floccular sludge, as assessed by Next Generation Sequencing (NGS). Dewatering measurements showed, as expected, that the settling velocity of granules was much faster than flocs at solids concentrations below the gel point. At at higher solids concentrations above the gel point, however, both flocs and granules form a similar gelled network structure with no significant difference in dewaterability. We used the dewatering properties in process models to predict the impact of granulation on thickener and filter throughput. Overall, this work highlights the biological, structural and physical differences and similarities between granular and floccular sludges with the outcome being improved settling for granules but no significant difference in downstream dewatering properties that pertain to filtration processes. Refereed/Peer-reviewed

We introduce an approach to modular dimensionality reduction, allowing efficient learning of multiple complementary representations of the same object. Modules are trained by optimising an unsupervised cost function which balances two competing goals: Maintaining the inner product structure within the original space, and encouraging structural diversity between complementary representations. We derive an efficient learning algorithm which outperforms gradient based approaches without the need to choose a learning rate. We also demonstrate an intriguing connection with Dropout. Empirical results demonstrate the efficacy of the method for image retrieval and classification.

Refereed/Peer-reviewed Conventional activated sludge (CAS)-based wastewater treatment processes have the potential to emit high concentrations of nitrous oxide (N₂O) during nitrification and denitrification, which can significantly impact the environmental performance and carbon footprint of wastewater treatment operations. While N₂O emissions from CAS have been extensively studied, there is little knowledge of N₂O emissions from aerobic granular sludge (AGS) which is now an increasingly popular secondary treatment alternative. The N₂O emissions performance of AGS needs to be investigated to ensure that the positive benefits of AGS, such as increased capacity and stable nutrient removal, are not offset by higher emissions. This study quantified N₂O emissions from a pilot-scale AGS reactor operated under a range of organic loading rates. A second CAS pilot plant was operated in parallel and under identical loading rates to allow for side-by-side comparison of N₂O emissions from floc-based activated sludge. Under low loadings of

Ultrafiltration (UF) membrane technology is widely used in water recycling schemes as a physical barrier for the removal of human pathogens. Assessing the consequence of long-term operation (membrane ageing) as well operational extremes on pathogen removal performance is crucial for assessing health risks of human exposure to recycled water. In this study, challenge testing with MS2 bacteriophage (MS2) was undertaken to validate the integrity of full-scale UF membranes used for virus removal in a wastewater recycling plant (WRP). Validation was performed on new (6 months old) and aged (6 years old) membrane units. The impact of a hazardous event - in the form of a short-lived, high turbidity spike - was also assessed since this event affected the hydraulic throughput of exposed membrane units. Validation of the new membranes demonstrated a mean virus log removal value (LRV) of 3.0log10 (SD = 0.6), with 5th and 95th percentile values ranging between 2.3 and 3.9log10 units. Re-validation of the membranes exposed to the hazardous event as well as those that were aged demonstrated that the virus LRV was comparable and had reduced by 1.0log10 units, measuring 2.0log10 (SD = 0.2), however the LRV performance was more stable, where the 5th and 95th percentile values ranged between only 1.7 and 2.2log10 units. Very little research has previously examined the consequence of membrane ageing or hazardous events on the LRV performance of full-scale UF systems, and thus the findings presented here will facilitate improvements in risk management, in the design of installations and in the operation of UF membrane systems. usc Refereed/Peer-reviewed

Fingermarks are a key form of physical evidence for identifying persons of interest and linking them to the scene of a crime. Visualising latent (hidden) fingermarks can be difficult and the correct choice of techniques is essential to develop and preserve any fingermarks or other (e.g. DNA) evidence that might be present. Metal surfaces (stainless steel in particular) have proven to be challenging substrates from which to reliably obtain fingermarks. This is a great cause for concern among police forces around the globe as many of the firearms, knives and other metal weapons used in violent crime are potentially valuable sources of fingermark evidence. In this study, a highly sensitive and non-destructive surface science technique called time of flight secondary ion mass spectroscopy (ToF-SIMS) was used to image fingermarks on metal surfaces. This technique was compared to a conventional superglue based fuming technique that was accompanied by a series of contrast enhancing dyes (basic yellow 40 (BY40), crystal violet (CV) and sudan black (SB)) on three different metal surfaces. The conventional techniques showed little to no evidence of fingermarks being present on the metal surfaces after a few days. However, ToF-SIMS revealed fingermarks on the same and similar substrates with an exceptional level of detail. The ToF-SIMS images demonstrated clear ridge definition as well as detail about sweat pore position and shape. All structures were found to persist for over 26 days after deposition when the samples were stored under ambient conditions.

The successful development of aerobic granular sludge (AGS) for secondary wastewater treatment has been linked to a dedicated anaerobic feeding phase, which enables key microbes such as poly-phosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms to gain a competitive advantage over floc-forming organisms. The application of AGS to treat high-saline sewage and its subsequent impacts on microbial ecology, however, are less well understood. In this study, the impacts of high-saline sewage on AGS development, performance and ecology were investigated using molecular microbiology methods. Two feeding strategies were compared at pilot scale: a full (100%) anaerobic feed; and a partial (33%) anaerobic feed. The results were compared to a neighbouring full-scale conventional activated sludge (CAS) system (100% aerobic). We observed that AGS developed under decreased anaerobic contact showed a comparable formation, stability and nitrogen removal performance to the 100% anaerobically fed system. Analysis of the microbial ecology showed that the altered anaerobic contact had minimal effect on the abundances of the functional nitrifying and denitrifying bacteria and Archaea; however, there were notable ecological differences when comparing different sized granules. In contrast to previous work, a large enrichment in PAOs in AGS was not observed in high-saline wastewater, which coincided with poor observed phosphate removal performance. Instead, AGS exhibited a substantial enrichment in sulfide-oxidising bacteria, which was complemented by elemental analysis that identified the presence of elemental sulfur precipitation. The potential role for these organisms in AGS treating high-saline wastewater is discussed.

Membranes are an important barrier used in recycled water treatment plants for pathogen removal. Understanding performance over operational life is important to inform membrane replacement. In this study, full scale virus challenge testing was conducted on newly commissioned membranes to validate virus log removal values for accreditation. After six years of operation, the membrane integrity was repeated to ensure compliance with the state regulatory health authority and gain an understanding of the asset's condition. Membrane performance was assessed using a combination of complementary tests including membrane autopsy and chemical tolerance testing to assess individual modules and selected membrane fibres, followed by a full scale virus challenge for whole of unit assessment. The results demonstrated that the aged membrane fibres were intact and had not been affected by long-term exposure to chlorine, which provides valuable information for membrane asset replacement strategies.

An 829-bp fragment of the NADH dehydrogenase subunit 2 (NADH2) gene was used to assess the taxonomic status of 1487 elasmobranch specimens, representing 52 putative species. Strong evidence was found for the existence of an undescribed Echinorhinus species and for cryptic speciation within Rhynchobatus djiddensis. The results also provide strong molecular support for the existence of two previously reported, but undescribed, guitarfish species. Potential, but less conclusive, cryptic lineage diversification was also noted in Carcharhinus leucas, Loxodon macrorhinus, Iago omanensis and Gymnura poecilura. A complex situation was found in the genus Himantura, with potentially three distinct lineages evident, one of which is probably an undescribed species, in the H. gerrardi complex. One dasyatid specimen could not be identified, but appears to be closely related to Dasyatis ushiei, while Himantura leoparda and Carcharhinus longimanus are reported from Oman for the first time. The results of the present study also reinforce previously reported geographical divisions within certain putative species, which has important implications for fishery management and conservation. © 2015 The Linnean Society of London

Free-ocean CO2 enrichment (FOCE) systems are designed to assess the impact of ocean acidification on biological communities in situ for extended periods of time (weeks to months). They overcome some of the drawbacks of laboratory experiments and field observations by enabling (1) precise control of CO2 enrichment by monitoring pH as an offset of ambient pH, (2) consideration of indirect effects such as those mediated through interspecific relationships and food webs, and (3) relatively long experiments with intact communities. Bringing perturbation experiments from the laboratory to the field is, however, extremely challenging. The main goal of this paper is to provide guidelines on the general design, engineering, and sensor options required to conduct FOCE experiments. Another goal is to introduce xFOCE, a community-led initiative to promote awareness, provide resources for in situ perturbation experiments, and build a user community. Present and existing FOCE systems are briefly described and examples of data collected presented. Future developments are also addressed as it is anticipated that the next generation of FOCE systems will include, in addition to pH, options for oxygen and/or temperature control. FOCE systems should become an important experimental approach for projecting the future response of marine ecosystems to environmental change.

In this study we investigated the environmental regulation of daily reproductive activity of guppies (Poecilia reticulata). We observed male guppy reproductive behaviour for 17 days over three time periods (dawn, noon, and dusk) while recording natural variation in water temperature and light level. Water temperatures recorded during the experiments were highly variable (up to 7 °C per day), and there was a recurring pattern in daily variation for both light and temperature. Levels of activity were highest at dawn and similarly low during noon and dusk, but reproductive behaviour was recorded throughout the day. Mixed-effects models indicate that light and temperature affect reproductive behaviour differently at different times of the day, and can also have opposing effects. We suggest that the environmental heterogeneity of streams in Trinidad has led to a broad thermal tolerance, and has contributed to the high level of phenotypic plasticity in the guppy and its success as an invasive species. Furthermore, our results show that daily variation in temperature and its interaction with light should be considered in future studies of guppy reproductive behaviour. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 511–520.

The anatomy of the male and female reproductive systems was investigated in the long-tailed butterfly ray Gymnura poecilura using gross observation and light microscopy. The testes are highly asymmetrical, to the extent that only the left testis is functional and the right testis is completely absent. Both of the male genital ducts are present and symmetrical, although spermatozoa only occur in the left duct. The genital ducts are straight and unconvoluted, with regular incomplete internal partitions throughout. Females do not possess a right ovary, nor do the oviducal glands exhibit distinct club and papillary zones, and the baffle zone lacks baffle plates. In all sections of the gland, the tubules display different secretory activities depending on the proximity to the gland lumen. The gland produces a thin egg membrane that encases each egg individually, while the endometrium is formed into trophonemata.

Aflatoxin concentration data for a range of foods available in New Zealand (maize products, nuts and nut products, dried fruits and spices) were combined with dietary recall food consumption information from New Zealand national nutrition surveys to derive exposure estimates for a range of age-gender groups. Mean exposure estimates for total aflatoxins ranged from 0.09-0.11 ng/kg body weight/day for adult females, to 0.32-0.39 ng/kg body weight/ day for 5-10 year old children. Spices were the major contributors to dietary exposure for all population subgroups, followed by nuts and nut products. However, the contribution of spices to total dietary exposure could be traced to a single sample with a very high concentration. A life-time weighted average aflatoxin exposure was derived for New Zealand males and females and was combined with cancer potency estimates to give an assessment of risk. The mean risk equates to a potential for less than one excess cancer every 10 years.

Dwarf cereal crops are widely grown world-wide because they offer productivity advantages to farmers, but the question of whether dwarfing genes change starch structure has not been examined. Starch properties, including digestion rate and mechanical properties of starch-containing biomaterials, are influenced by its structure, and thus significant changes might have health implications. Starch molecular structures of the grains from a semi-dwarf sd1 rice (Oryza sativa L.) mutant (Calrose 76) and its near-isogenic wild-type (Calrose) counterpart as well as of those from three dwarf sorghum (Sorghum bicolor L.) mutants and their near-isogenic tall revertants (due to the spontaneous reverse mutation of dw3 gene) were analyzed to understand the pleiotropic effects of dwarfing genes on starch biosynthesis in the grains. The structures of (fully branched) whole starch molecules and branch-chain length (from enzymatically debranched starch) were characterized using size-exclusion chromatography. The weight-average MW and radius of gyration of whole starch molecules were characterized using multiple-angle laser light scattering. There were no significant structural differences between each dwarf variety and its near-isogenic wild-type or tall revertant counterpart. Hence plant height reduction in rice and sorghum, controlled by the sd1 and dw3 genes, respectively, does not affect the biosynthesis of starch molecules in grains and is expected to have no significant impacts on starch crystalline and granular structures as well as starch functional properties, including its nutritional values.

A semi-anthropomorphic 'distal radius like' phantom, developed by Kalender and Ruegsegger for use in peripheral bone densitometry using single photon (DPA) dual X-ray (DXA) and quantitative computed tomography (QCT) machines, has been studied with a view to cross-calibrating different types and brands of densitometers in current use. In the context of an EU 'Concerted Action' (second Framework Programme) the phantom was repeatedly measured on six SPA machines, three DXA machines and nine QCT machines (545 measurements). Linear regression equations were derived, individual to each machine, which allowed the derivation of 'standardized densities'. In this way we converted measurements made by machines of the same modality to a common scale of measurements. Two machines (one DXA, one SPA) showed statistically significant instability over time emphasising the need for rigorous quality control in the application of densitometry. In other respects these results provide an encouraging basis for the derivation of standardized normative ranges and the more effective use of peripheral densitometry in future clinical and epidemiological studies.

To avoid the complication of osteoporosis, hormone replacement therapy (HRT) is now standard therapy in women with premature ovarian failure. The indications for HRT after the age of 50 are more controversial. There are strong indications from case-control studies that in N. America and Europe HRT protects against osteoporotic fracture, myocardial infarction and stroke; yet the evidence from case control studies is insufficiently precise to quantitate accurately the potential benefits that would accrue from its more widespread use. Clear guidelines also need to be established on the potential usefulness of selective prescribing of HRT using one or more screening procedures. The only effective way of achieving this and of quantitating the potential benefits of HRT with sufficient accuracy is by means of one or more randomized controlled trials. Future research will also address concerns such as the possible increase in the risk of breast cancer after 10 or more years of therapy. Critical to the more widespread acceptance of HRT may be the development of safe regimes which do not promote uterine bleeding as well as minimizing other unwanted side-effects.

Blood flow to bone was measured using the 18F clearance method described by Wootton et al. (1976) in osteomalacia (nine cases) and primary hyperparathyroidism (eight cases). Bone blood flow was elevated above normal in the osteomalacia group and was normal in the hyperparathyroid group (range 3.6%-6.8% blood volume/min). It is suggested that bone blood flow is linked with the osteoblastic response of bone, and remains normal in cases of hyperparathyroidism when no clinical signs of bone involvement are present.