Methods for Generating High-Fidelity Trace Chemical Residue Reflectance Signatures for Active Spectroscopy Classification Applications

Standoff detection and identification of trace chemicals in hyperspectral infrared images is an enabling capability in a variety of applications relevant to defense, law enforcement, and intelligence communities. Performance of these methods is impacted by the spectral signature variability due to the presence of contaminants, surface roughness, nonlinear effects, etc. Though multiple classes of algorithms exist for the detection and classification of these signatures, they are limited by the availability of relevant reference datasets. In this work, we first address the lack of physics-based models that can accurately predict trace chemical spectra. Most available models assume that the chemical takes the form of spherical particles or uniform thin films. A more realistic chemical presentation that could be encountered is that of a non-uniform chemical film that is deposited after evaporation of the solvent which contained the chemical. This research presents an improved signature model for this type of solid film. The proposed model, called sparse transfer matrix (STM), includes a log-normal distribution of film thicknesses and is found to reduce the root-mean-square error between simulated and measured data by about 25% when compared with either the particle or uniform thin film models. When applied to measured data, the sparse transfer matrix model provides a 0.10-0.28 increase in classification accuracy over traditional models. There remain limitations in the STM model which prevent the predicted spectra from being well-matched to the measured data in some cases. To overcome this, we leverage the field of domain adaptation to translate data from the simulated to the measured data domain. This thesis presents the first one-dimensional (1D) conditional generative adversarial network (GAN) to perform spectrum-to-spectrum translation of reflectance signatures. We apply the 1D conditional GAN to a library of simulated spectra and quantify the improvement with the translated library. The method demonstrates an increase in overall classification accuracy to 0.723 from the accuracy of 0.622 achieved using the STM model when tested on real data. However, the performance improvement is biased towards data included in the GAN training set. The next phase of the research focuses on learning models that are more robust to different parameter combinations for which we do not have measured data. This part of the research leverages elements from the field of theory-guided data science. Specifically, we develop a physics-guided neural network (PGNN) for predicting chemical reflectance for a set of parameterized inputs that is more accurate than the state-of-the-art physics-based signature model for chemical residues. After training the PGNN, we use it to generate a library of predicted spectra for training a classifier. We compare the classification accuracy when using this PGNN library versus a library generated by the physics-based model. Using the PGNN, the average classification accuracy increases to 0.813 on real chemical reflectance data, including data from chemicals not included in the PGNN training set. The products of this thesis work include methods for producing realistic trace chemical residue reflectance signatures as well as demonstrations of improved performance in active spectroscopy classification applications. These methods provide great value to a range of scientific communities. The novel STM signature model enables existing spectroscopy sensors and algorithms to perform well on real-world problems where chemical contaminants are non-uniform. The 1D conditional GAN is the first of its kind and can be applied to many other 1D datasets, such as audio and other time-series data. Finally, the application of theory-guided data science to the trace chemical problem not only enhances the quality of results for known targets and backgrounds, but also increases the robustness to new targets

Tumour excisional surgery, anaesthetic-analgesic techniques, and oncologic outcomes : a narrative review

Peer reviewedPublisher PD

Healthcare providers' views on the acceptability of financial incentives for breastfeeding:a qualitative study

BACKGROUND: Despite a gradual increase in breastfeeding rates, overall in the UK there are wide variations, with a trend towards breastfeeding rates at 6–8 weeks remaining below 40% in less affluent areas. While financial incentives have been used with varying success to encourage positive health related behaviour change, there is little research on their use in encouraging breastfeeding. In this paper, we report on healthcare providers’ views around whether using financial incentives in areas with low breastfeeding rates would be acceptable in principle. This research was part of a larger project looking at the development and feasibility testing of a financial incentive scheme for breastfeeding in preparation for a cluster randomised controlled trial. METHODS: Fifty–three healthcare providers were interviewed about their views on financial incentives for breastfeeding. Participants were purposively sampled to include a wide range of experience and roles associated with supporting mothers with infant feeding. Semi-structured individual and group interviews were conducted. Data were analysed thematically drawing on the principles of Framework Analysis. RESULTS: The key theme emerging from healthcare providers’ views on the acceptability of financial incentives for breastfeeding was their possible impact on ‘facilitating or impeding relationships’. Within this theme several additional aspects were discussed: the mother’s relationship with her healthcare provider and services, with her baby and her family, and with the wider community. In addition, a key priority for healthcare providers was that an incentive scheme should not impact negatively on their professional integrity and responsibility towards women. CONCLUSION: Healthcare providers believe that financial incentives could have both positive and negative impacts on a mother’s relationship with her family, baby and healthcare provider. When designing a financial incentive scheme we must take care to minimise the potential negative impacts that have been highlighted, while at the same time recognising the potential positive impacts for women in areas where breastfeeding rates are low

Dating human skeletal remains using 90Sr and 210Pb: case studies. [Dating human skeletal remains using Sr-90 and Pb-210: Case studies]

In legal medicine, the post mortem interval (PMI) of interest covers the last 50 years. When only human skeletal remains are found, determining the PMI currently relies mostly on the experience of the forensic anthropologist, with few techniques available to help. Recently, several radiometric methods have been proposed to reveal PMI. For instance, (14)C and (90)Sr bomb pulse dating covers the last 60 years and give reliable PMI when teeth or bones are available. (232)Th series dating has also been proposed but requires a large amount of bones. In addition, (210)Pb dating is promising but is submitted to diagenesis and individual habits like smoking that must be handled carefully. Here we determine PMI on 29 cases of forensic interest using (90)Sr bomb pulse. In 12 cases, (210)Pb dating was added to narrow the PMI interval. In addition, anthropological investigations were carried out on 15 cases to confront anthropological expertise to the radiometric method. Results show that 10 of the 29 cases can be discarded as having no forensic interest (PMI>50 years) based only on the (90)Sr bomb pulse dating. For 10 other cases, the additional (210)Pb dating restricts the PMI uncertainty to a few years. In 15 cases, anthropological investigations corroborate the radiometric PMI. This study also shows that diagenesis and inter-individual difference in radionuclide uptake represent the main sources of uncertainty in the PMI determination using radiometric methods

Cellulose consolidation under high-pressure and high-temperature uniaxial compression

Materials based on cellulose cannot be obtained from thermoplastic processes. Our aim is to prepare all-cellulose materials by uniaxial high pressure thermocompression of cellulose. The effect of moisture content (0–8 w/w%) and temperature (175–250 °C) was characterized through the mechanical properties (bending and tensile), morphology (scanning electron microscopy, X-ray tomography) and microstructure (viscometric degree of polymerization, Raman spectroscopy, X-ray diffraction, solid-state NMR) of the specimens. The specimens were mechanically stronger in bending than in tension. They exhibited a more porous heart, a dense but very thin skin on the faces (orthogonal to the compression axis) and thick and extremely dense sides. During thermocompression severe friction between fibers caused a decrease in molecular weight while heating above the glass transition temperature was responsible for water migration towards the specimen heart. Most of the cohesion came from the small sides of the test samples (parallel to the compression axis) and seemed mainly related to the entanglement of amorphized cellulose at the interface between particles. Around 200 °C water accumulated and provoked delamination upon pressure release, but at higher temperatures water, in a subcritical state, may have been consumed during the hydrolysis of amorphous cellulose regions. The all-cellulose material with the best mechanical properties was obtained at 2% moisture and 250 °C. This work shows that thermocompression at high temperature with limited moisture may be viable to produce renewable, sustainable all-cellulose materials for application in biobased plastic substitutes including binderless boards

The One Health Approach to Toxoplasmosis: Epidemiology, Control, and Prevention Strategies

One Health is a collaborative, interdisciplinary effort that seeks optimal health for people, animals, plants, and the environment. Toxoplasmosis, caused by Toxoplasma gondii, is an intracellular protozoan infection distributed worldwide, with a heteroxenous life cycle that practically affects all homeotherms and in which felines act as definitive reservoirs. Herein, we review the natural history of T. gondii, its transmission and impacts in humans, domestic animals, wildlife both terrestrial and aquatic, and ecosystems. The epidemiology, prevention, and control strategies are reviewed, with the objective of facilitating awareness of this disease and promoting transdisciplinary collaborations, integrative research, and capacity building among universities, government agencies, NGOs, policy makers, practicing physicians, veterinarians, and the general public

Prebiotic effects: metabolic and health benefits

The different compartments of the gastrointestinal tract are inhabited by populations of micro-organisms. By far the most important predominant populations are in the colon where a true symbiosis with the host exists that is a key for well-being and health. For such a microbiota, 'normobiosis' characterises a composition of the gut 'ecosystem' in which micro-organisms with potential health benefits predominate in number over potentially harmful ones, in contrast to 'dysbiosis', in which one or a few potentially harmful micro-organisms are dominant, thus creating a disease-prone situation. The present document has been written by a group of both academic and industry experts (in the ILSI Europe Prebiotic Expert Group and Prebiotic Task Force, respectively). It does not aim to propose a new definition of a prebiotic nor to identify which food products are classified as prebiotic but rather to validate and expand the original idea of the prebiotic concept (that can be translated in 'prebiotic effects'), defined as: 'The selective stimulation of growth and/or activity(ies) of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host.' Thanks to the methodological and fundamental research of microbiologists, immense progress has very recently been made in our understanding of the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. Thus the prebiotic effect is now a well-established scientific fact. The more data are accumulating, the more it will be recognised that such changes in the microbiota's composition, especially increase in bifidobacteria, can be regarded as a marker of intestinal health. The review is divided in chapters that cover the major areas of nutrition research where a prebiotic effect has tentatively been investigated for potential health benefits. The prebiotic effect has been shown to associate with modulation of biomarkers and activity(ies) of the immune system. Confirming the studies in adults, it has been demonstrated that, in infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, especially an increase of faecal concentrations of bifidobacteria. This concomitantly improves stool quality (pH, SCFA, frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema. Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. The use of particular food products with a prebiotic effect has thus been tested in clinical trials with the objective to improve the clinical activity and well-being of patients with such disorders. Promising beneficial effects have been demonstrated in some preliminary studies, including changes in gut microbiota composition (especially increase in bifidobacteria concentration). Often associated with toxic load and/or miscellaneous risk factors, colon cancer is another pathology for which a possible role of gut microbiota composition has been hypothesised. Numerous experimental studies have reported reduction in incidence of tumours and cancers after feeding specific food products with a prebiotic effect. Some of these studies (including one human trial) have also reported that, in such conditions, gut microbiota composition was modified (especially due to increased concentration of bifidobacteria). Dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase Ca absorption as well as bone Ca accretion and bone mineral density. Recent data, both from experimental models and from human studies, support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain. Together, with data in obese animals and patients, these studies support the hypothesis that gut microbiota composition (especially the number of bifidobacteria) may contribute to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2. It is plausible, even though not exclusive, that these effects are linked to the microbiota-induced changes and it is feasible to conclude that their mechanisms fit into the prebiotic effect. However, the role of such changes in these health benefits remains to be definitively proven. As a result of the research activity that followed the publication of the prebiotic concept 15 years ago, it has become clear that products that cause a selective modification in the gut microbiota's composition and/or activity(ies) and thus strengthens normobiosis could either induce beneficial physiological effects in the colon and also in extra-intestinal compartments or contribute towards reducing the risk of dysbiosis and associated intestinal and systemic pathologies

Racial Justice in Housing Finance: A Series on New Directions

The enclosed essays speak from a range of diverse viewpoints to explore how housing finance can be harnessed towards the ends of residential integration, equitable investment, and housing security, rather than purely for profit. Our authors offer ideas across a spectrum of proposed reforms. They describe how aspects of our current housing finance system derive from, or fail to correct for, our deep history of structural racism; they propose concrete steps toward re-engineering our current regulatory structure and housing programs to better advance equity, including addressing the particular harms of racial segregation; and they argue for expanded social housing and other visionary reforms