Development of an Electronic Nose for Olfactory System Modelling using Artificial Neural Network

Electronic nose (e-nose) devices have received considerable attention in the field of sensor technology because of their many potential uses such as in identification of toxic wastes, monitoring air quality, examining odors in infected wounds and in inspection of food. Notwithstanding the vast amount of literature on the usage of e-noses for specific purposes, the technology originally and ultimately aims to mimic the capability of mammals to discriminate odors from all sorts of objects. This study demonstrates the theoretical and practical feasibility of designing an e-nose towards general odor classification. A multi-sensor array hardware unit was carefully constructed for data collection and odor detection. Important hardware design considerations such as sensor calibration, aeration, circuit protection, and voltage/current requirements were satisfied. A highly fine-tuned artificial neural network (ANN) was integrated to the hardware to interpret and relate the data to a target odor class from a set of 10 primary odors identified in a previous study. Various network architecture considerations, such as neuron count, number of layers and activation function, as well as various data treatment methods, such as normalization, and data partitioning, were investigated. The results showed that careful hardware integration with an ANN having sufficiently deep internal structure can yield accurate classification to at least half of the ten primary odor classes, namely fragrant (96%), fruity (98%), chemical (99%), peppermint (98%), and popcorn (90%). The results demonstrate the feasibility of making e-noses for general odor classification, which could lead to further broadening of e-nose applications

Development of design tools for the evaluation of complex CAD models

The goal of this thesis is to invent means to enable 3D-models, created in SOLIDWORKS CAD-software, to be explored in a low-cost head-mounted display device Oculus Rift. Such a design tool would make possible to study 3D CAD-models in Virtual Reality with a very low cost and share design information for people who are not so familiar with CAD-models. As a result this can lower the product development effort for new products enabling, lower working time and improve both the quality of the final product and customer satisfaction. CAD-models as well as exported graphics format from SOLIDWORKS can’t directly be imported to Oculus Rift device. Therefore transformation pipeline need to be invented between the SOLIDWORKS and Oculus Rift. There are some options for this and their issues are studied in this thesis. As a best option it was found to use a conversion plugin tool to SOLIDWORKS which convert CAD-models to FBX-format. This format can be imported to Unity game engine software which is supported by Oculus Rift device. Graphics file conversion process in known to be imperfect. Therefore conversion of three SOLIDWORKS CAD-models have been analyzed; a Crane, a Pipe system, and a Hydraulic cylinder. This testing gave a good overview of possibilities and limitations of the graphics pipeline. It was found that ordinary CAD-models can be transferred to Oculus Rift without problems. However, there are some special features in CAD models which cause problems for in graphics file conversion

Interpopulational and seasonal variation in the chemical signals of the lizard Gallotia galloti

Communicative traits are strikingly diverse and may vary among populations of the same species. Within a population, these traits may also display seasonal variation. Chemical signals play a key role in the communication of many taxa. However, we still know far too little about chemical communication in some vertebrate groups. In lizards, only a few studies have examined interpopulational variation in the composition of chemical cues and signals and only one study has explored the seasonal effects. Here we sampled three subspecies of the Tenerife lizards (Gallotia galloti) and analyze the lipophilic fraction of their femoral gland secretions to characterize the potential interpopulational variation in the chemical signals. In addition, we assessed whether composition of these secretions differed between the reproductive and the non-reproductive season. We analyzed variations in both the overall chemical profile and the abundance of the two main compounds (cholesterol and vitamin E). Our results show interpopulational and seasonal differences in G. gallotia chemical profiles. These findings are in accordance with the high interpopulational variability of compounds observed in lizard chemical signals and show that their composition is not only shaped by selective factors linked to reproductive season

Bathymetry and vertical temperature profile of Lake Mainit

Abstract only.The bottom topography and vertical temperature profile of Lake Mainit was assessed to provide baseline data to understand the dynamic behavior of the lake as an ecosystem. Many limnological phenomena, distribution of biota, and productivity were directly related to the morphological features of the lake basin. The bottom topography was assessed using echo sounding method. Vertical temperature profile of the lake was evaluated using reversing thermometers mounted on Nansen reversing samplers. All data points were marked by geographic positioning system. Results indicated that the maximum recorded depth was 218.75 m based on current surface elevation of Lake Mainit. The deep portions of the lake with steep shoreline profile were observed in the vicinity along the Malimono ridge. Areas in the lake with more than 200 m depth were observed between Bonga and the islets of Kitcharao. Coasts along Mainit and the eastern part of the lake, except the Kitcharao Park which is rocky, have sloping shoreline. The vertical temperature profile of Lake Mainit ranged between 26.55° - 30°C. The thermocline layer was observed between 10 m to 40 m. The variation in vertical temperature was observed at the surface and at levels down to a depth of 30 m. Beyond 30 m, there was a minute variation of temperature that ranged between 0.03° - 0.15°C

Mental health of migrants with pre-migration exposure to armed conflict: a systematic review and meta-analysis.

BACKGROUND Exposure to armed conflict has been associated with negative mental health consequences. We aimed to estimate the prevalence of generalised anxiety disorder, major depressive disorder, and post-traumatic stress disorder among migrants exposed to armed conflict. METHODS In this systematic review and meta-analysis, we searched online databases (Cochrane Library, Embase, LILACS, PsycInfo [via Ovid], PubMed, and Web of Science Core Collection) for relevant observational studies published between Jan 1, 1994, and June 28, 2021. We included studies that used standardised psychiatric interviews to assess generalised anxiety disorder, major depressive disorder, or post-traumatic stress disorder among migrants (refugees or internally displaced persons; aged ≥18 years) with pre-migration exposure to armed conflict. We excluded studies in which exposure to armed conflict could not be ascertained, studies that included a clinical population or people with chronic diseases that can trigger the onset of mental disease, and studies published before 1994. We used a random effects model to estimate each mental health disorder's pooled prevalence and random effects meta-regression to assess sources of heterogeneity. Two independent reviewers assessed the risk of bias for each study using the Joanna Briggs Institute Checklist for Prevalence Studies. The protocol was registered with PROSPERO, CRD42020209251. FINDINGS Of the 13 935 studies identified, 34 met our inclusion criteria; these studies accounted for 15 549 migrants. We estimated a prevalence of current post-traumatic stress disorder of 31% (95% CI 23-40); prevalence of current major depressive disorder of 25% (17-34); and prevalence of generalised anxiety disorder of 14% (5-35). Younger age was associated with a higher prevalence of current post-traumatic stress disorder (odds ratio 0·95 [95% CI 0·90-0·99]), lifetime post-traumatic stress disorder (0·88 [0·83-0·92]), and current generalised anxiety disorder (0·87 [0·78-0·97]). A longer time since displacement was associated with a lower lifetime prevalence of post-traumatic stress disorder (0·88 [0·81-0·95]) and major depressive disorder (0·81 [0·77-0·86]). Migrating to a middle-income (8·09 [3·06-21·40]) or low-income (39·29 [11·96-129·70]) country was associated with increased prevalence of generalised anxiety disorder. INTERPRETATION Migrants who are exposed to armed conflict are at high risk of mental health disorders. The mental health-care needs of migrants should be assessed soon after resettlement, and adequate care should be provided, with particular attention paid to young adults. FUNDING Marie Skłodowska-Curie Actions (Horizon 2020-COFUND), MinCiencias (Colombia), and Swiss National Science Foundation

New Orleans and Hurricane Katrina. III: The 17th Street Drainage Canal

The failure of the levee and floodwall section on the east bank of the 17th Street drainage canal was one of the most catastrophic breaches that occurred during Hurricane Katrina. It produced a breach that rapidly scoured a flow pathway below sea level, so that after the storm surge had largely subsided, floodwaters still continued to stream in through this breach for the next two and a half days. This particular failure contributed massively to the overall flooding of the Metropolitan Orleans East Bank protected basin. Slightly more than half of the loss of life, and a similar fraction of the overall damages, occurred in this heavily populated basin. There are a number of important geotechnical and geoforensic lessons associated with this failure. Accordingly, this paper is dedicated solely to investigating this single failure. Geological and geotechnical details, such as a thin layer of sensitive clay that was laid down by a previous hurricane, proper strength characterization of soils at and beyond the toe of the levee, and recognition of a water-filled gap on the inboard side of the sheet pile cutoff wall are judged to be among the most critical factors in understanding this failure. The lessons learned from this study are of importance for similar flood protection systems throughout other regions of the United States and the world

Investigation of the Performance of the New Orleans Flood Protection System in Hurricane Katrina on August 29, 2005: Volume 1

This report presents the results of an investigation of the performance of the New Orleans regional flood protection system during and after Hurricane Katrina, which struck the New Orleans region on August 29, 2005. This event resulted in the single most costly catastrophic failure of an engineered system in history. Current damage estimates at the time of this writing are on the order of $100 to$200 billion in the greater New Orleans area, and the official death count in New Orleans and southern Louisiana at the time of this writing stands at 1,293, with an additional 306 deaths in nearby southern Mississippi. An additional approximately 300 people are currently still listed as “missing”; it is expected that some of these missing were temporarily lost in the shuffle of the regional evacuation, but some of these are expected to have been carried out into the swamps and the Gulf of Mexico by the storm’s floodwaters, and some are expected to be recovered in the ongoing sifting through the debris of wrecked homes and businesses, so the current overall regional death count of 1,599 is expected to continue to rise a bit further. More than 450,000 people were initially displaced by this catastrophe, and at the time of this writing more than 200,000 residents of the greater New Orleans metropolitan area continue to be displaced from their homes by the floodwater damages from this storm event. This investigation has targeted three main questions as follow: (1) What happened?, (2) Why?, and (3) What types of changes are necessary to prevent recurrence of a disaster of this scale again in the future? To address these questions, this investigation has involved: (1) an initial field reconnaissance, forensic study and data gathering effort performed quickly after the arrival of Hurricanes Katrina (August 29, 2005) and Rita (September 24, 2005), (2) a review of the history of the regional flood protection system and its development, (3) a review of the challenging regional geology, (4) detailed studies of the events during Hurricanes Katrina and Rita, as well as the causes and mechanisms of the principal failures, (4) studies of the organizational and institutional issues affecting the performance of the flood protection system, (5) observations regarding the emergency repair and ongoing interim levee reconstruction efforts, and (6) development of findings and preliminary recommendations regarding changes that appear warranted in order to prevent recurrence of this type of catastrophe in the future. In the end, it is concluded that many things went wrong with the New Orleans flood protection system during Hurricane Katrina, and that the resulting catastrophe had it roots in three main causes: (1) a major natural disaster (the Hurricane itself), (2) the poor performance of the flood protection system, due to localized engineering failures, questionable judgments, errors, etc. involved in the detailed design, construction, operation and maintenance of the system, and (3) more global “organizational” and institutional problems associated with the governmental and local organizations responsible for the design, construction, operation, maintenance and funding of the overall flood protection system

Depth-Sensing Indentation on REBa2Cu3O(7-\delta) Single Crystals obtained from Xenotime Mineral

A natural mixture of heavy rare earths oxides extracted from xenotime mineral have been used to prepare large single crystals of high-temperature REBa2Cu3O(7-\delta) superconductor grown using the CuO-BaO self-flux method. Its mechanical properties along the ab-plane were characterized using instrumented indentation. Hardness and elastic modulus were obtained by the Oliver and Pharr method and corresponds to 7.4 \pm 0.2 GPa and in range 135-175 GPa at small depths, respectively. Increasing the load promotes the nucleation of lateral cracks that causes a decrease in hardness and the measured elastic modulus by instrumented indentation at higher loads. The indentation fracture toughness was estimated by measuring the radial crack length from cube-corner indentations at various loads and was 0.8 \pm 0.2 MPa.m1/2. The observed slip systems of REBa2Cu3O(7-\delta) single crystals were [100](001) and [010](001), the same as for YBa2Cu3O(7-\delta) single crystals. The initial stages of deformation and fracture in the indentation process were investigated. The hardness and elastic modulus were not strongly modified by the crystallographic orientation in the ab-plane. This was interpreted in terms of the resolved shear stresses in the active slip systems. Evidence of cracking along the {100} and {110} planes on the ab-plane was observed. As a conclusion, the mechanical properties of REBa2Cu3O(7-\delta) single crystals prepared from xenotime are equivalent to those of YBa2Cu3O(7-\delta) single crystals produced by conventional rare earths oxides.Comment: The paper will appear in Volume 42 (2012) of the Brazilian Journal of Physic

The Fanconi Anemia Core Complex Is Dispensable during Somatic Hypermutation and Class Switch Recombination

To generate high affinity antibodies during an immune response, B cells undergo somatic hypermutation (SHM) of their immunoglobulin genes. Error-prone translesion synthesis (TLS) DNA polymerases have been reported to be responsible for all mutations at template A/T and at least a fraction of G/C transversions. In contrast to A/T mutations which depend on PCNA ubiquitination, it remains unclear how G/C transversions are regulated during SHM. Several lines of evidence indicate a mechanistic link between the Fanconi Anemia (FA) pathway and TLS. To investigate the contribution of the FA pathway in SHM we analyzed FancG-deficient B cells. B cells deficient for FancG, an essential member of the FA core complex, were hypersensitive to treatment with cross-linking agents. However, the frequencies and nucleotide exchange spectra of SHM remained comparable between wild-type and FancG-deficient B cells. These data indicate that the FA pathway is not involved in regulating the outcome of SHM in mammals. In addition, the FA pathway appears dispensable for class switch recombination