Ecology impacts the decrease of Spirochaetes and Prevotella in the fecal gut microbiota of urban humans

Compared to the huge microbial diversity in most mammals, human gut microbiomes have lost diversity while becoming specialized for animal-based diets - especially compared to chimps, their genetically closest ancestors. The lowered microbial diversity within the gut of westernized populations has also been associated with different kinds of chronic inflammatory diseases in humans. To further deepen our knowledge on phylogenetic and ecologic impacts on human health and fitness, we established the herein presented biobank as well as its comprehensive microbiota analysis. In total, 368 stool samples from 38 different animal species, including Homo sapiens, belonging to four diverse mammalian orders were collected at seven different locations and analyzed by 16S rRNA gene amplicon sequencing. Comprehensive data analysis was performed to (i) determine the overall impact of host phylogeny vs. diet, location, and ecology and to (ii) examine the general pattern of fecal bacterial diversity across captive mammals and humans.By using a controlled study design with captive mammals we could verify that host phylogeny is the most dominant driver of mammalian gut microbiota composition. However, the effect of ecology appears to be able to overcome host phylogeny and should therefore be studied in more detail in future studies. Most importantly, our study could observe a remarkable decrease of Spirochaetes and Prevotella in westernized humans and platyrrhines, which is probably not only due to diet, but also to the social behavior and structure in these communities.Our study highlights the importance of phylogenetic relationship and ecology within the evolution of mammalian fecal microbiota composition. Particularly, the observed decrease of Spirochaetes and Prevotella in westernized communities might be associated to lifestyle dependent rapid evolutionary changes, potentially involved in the establishment of dysbiotic microbiomes, which promote the etiology of chronic diseases

DATA ANALYTICS FOR CRISIS MANAGEMENT: A CASE STUDY OF SHARING ECONOMY SERVICES IN THE COVID-19 PANDEMIC

This dissertation study aims to analyze the role of data-driven decision-making in sharing economy during the COVID-19 pandemic as a crisis management tool. In the twenty-first century, when applying analytical tools has become an essential component of business decision-making, including operations on crisis management, data analytics is an emerging field. To carry out corporate strategies, data-driven decision-making is seen as a crucial component of business operations. Data analytics can be applied to benefit-cost evaluations, strategy planning, client engagement, and service quality. Data forecasting can also be used to keep an eye on business operations and foresee potential risks. Risk Management and planning are essential for allocating the necessary resources with minimal cost and time and to be ready for a crisis. Hidden market trends and customer preferences can help companies make knowledgeable business decisions during crises and recessions. Each company should manage operations and response during emergencies, a path to recovery, and prepare for future similar events with appropriate data management tools. Sharing economy is part of social commerce, that brings together individuals who have underused assets and who want to rent those assets short-term. COVID-19 has emphasized the need for digital transformation. Since the pandemic began, the sharing economy has been facing challenges, while market demand dropped significantly. Shelter-in-Place and Stay-at-Home orders changed the way of offering such sharing services. Stricter safety procedures and the need for a strong balance sheet are the key take points to surviving during this difficult health crisis. Predictive analytics and peer-reviewed articles are used to assess the pandemic\u27s effects. The approaches chosen to assess the research objectives and the research questions are the predictive financial performance of Uber & Airbnb, bibliographic coupling, and keyword occurrence analyses of peer-reviewed works about the influence of data analytics on the sharing economy. The VOSViewer Bibliometric software program is utilized for computing bibliometric analysis, RapidMiner Predictive Data Analytics for computing data analytics, and LucidChart for visualizing data

Data Analytics for Crisis Management: A Case Study of Sharing Economy Services in the COVID-19 Pandemic

This dissertation study aims to analyze the role of data-driven decision-making in sharing economy during the COVID-19 pandemic as a crisis management tool. In the twenty-first century, when applying analytical tools has become an essential component of business decision-making, including operations on crisis management, data analytics is an emerging field. To carry out corporate strategies, data-driven decision-making is seen as a crucial component of business operations. Data analytics can be applied to benefit-cost evaluations, strategy planning, client engagement, and service quality. Data forecasting can also be used to keep an eye on business operations and foresee potential risks. Risk Management and planning are essential for allocating the necessary resources with minimal cost and time and to be ready for a crisis. Hidden market trends and customer preferences can help companies make knowledgeable business decisions during crises and recessions. Each company should manage operations and response during emergencies, a path to recovery, and prepare for future similar events with appropriate data management tools. Sharing economy is part of social commerce, that brings together individuals who have underused assets and who want to rent those assets short-term. COVID-19 has emphasized the need for digital transformation. Since the pandemic began, the sharing economy has been facing challenges, while market demand dropped significantly. Shelter-in-Place and Stay-at-Home orders changed the way of offering such sharing services. Stricter safety procedures and the need for a strong balance sheet are the key take points to surviving during this difficult health crisis. Predictive analytics and peer-reviewed articles are used to assess the pandemic\u27s effects. The approaches chosen to assess the research objectives and the research questions are the predictive financial performance of Uber & Airbnb, bibliographic coupling, and keyword occurrence analyses of peer-reviewed works about the influence of data analytics on the sharing economy. The VOSViewer Bibliometric software program is utilized for computing bibliometric analysis, RapidMiner Predictive Data Analytics for computing data analytics, and LucidChart for visualizing data

Interactions of fluorophores with complex surfaces and spectroscopic examinations of ancient manuscripts

In the first part of this thesis, it was found by fibre-optic fluorescence spectroscopy, that the greening of fabrics washed in optical brighteners is due to a reabsorption effect. The quantum yield of fluorescence of the optical brighteners OB15, OB36 and OB49 in water are $0.11$, $0.08$ and $0.71$ respectively. Their respective fluorescence natural lifetimes are $6700\pm109$, $5971\pm712$ and $1685\pm22$ ps. In solution, the excited state of OB15 experiences more competing relaxation processes as the solvatochromic shift increases. OB49 displays the opposite trend. A literature cellulose model surface is employed as a cotton mimic for evanescent wave fluorescence studies. Two model greases are similarly developed and used, and a third is presented for future work. These are based on surface-specific reactions with glass substrates, and the doping of a regenerated cellulose film with long chain alcohols. On doped cellulose surfaces, some low quantum yields occur compared to clean cellulose and bulk solution. Photobleaching behaviours are also observed. Both dyes physisorb rigidly to cellulose and grease models. The second part of this thesis identifies the pigment palette of the earliest Northumbrian manuscripts pre- and post-1066, by Raman and diffuse reflectance spectroscopy. It develops a suite of multispectral imaging programs in MATLAB for facile classification of pigments across a page ab initio, using data reduction and colour spaces. Raman and reflectance data are meta-analysed using symmetric permutation to split manuscripts and pigments into groups ab initio. It was also generalised, that the palette of the pre-Hastings selected manuscripts contained vergaut, indigo, orpiment, impure red lead, and copper green pigments, as well as orcein purples. Immediately post-1066 white lead, red ochre, vermilion and lapis lazuli appear in the palette in England, though vergaut and indigo disappear and the red lead used is essentially pure

Geochemical evolution of Andean arc volcanism and the uplift of the Andes

The Andean Plateau is the only modern-day orogenic plateau formed by subduction and not continental collision. The geodynamic mechanisms responsible for initiating crustal shortening and thickening in the Andes at ~70 Ma, after subduction had been ongoing for over 200 Ma, are still debated. The timing of Andean surface uplift is also controversial, and currently two models remain prevalent: (1) slow and steady uplift synchronous with crustal shortening from ~70-50 Ma, and (2) rapid surface uplift of up to 2 km in the last 20-16 Ma, resulting from large scale lower lithosphere removal or lower crustal flow. We find a very strong correlation between Nazca plate age entering the trench and Andean crustal thickness (r = 0.939; r2 = 0.882; p value < 0.01). Thrust earthquakes at the Nazca-South America plate interface occur only where the slab age at the trench is older than 30 Myr, except where oceanic ridges are colliding with the trench. Based on these observations a new hypothesis is proposed, that long-term subduction of intermediate aged oceanic lithosphere (~30-80 Myr) can provide an explanation for the initiation and distribution of crustal shortening in the Andean plate. Intermediate aged slabs have a greater mechanical strength than weak and young oceanic lithosphere (<30 Myr), but a greater positive buoyancy compared to older slabs. These slab properties combined with trench-ward overriding plate motion transmit higher compressional stress into the overriding South American plate than during other subduction zone configurations. A new approach is used to constrain regional Andean surface uplift. Cross correlations are tested between several physical parameters relating to the Andean subduction zone and several geochemical parameters from Andean arc volcanoes. 87Sr/86Sr and 143Nd/144Nd ratios have the strongest correlations with both crustal thickness and, due to isostasy, elevation. Very strong linear correlations exist between smoothed elevation and 87Sr/86Sr (R2=0.858, n=17) and 143Nd/144Nd (R2=0.919, n=16) ratios of non-plateau arc lavas. 87Sr/86Sr and 143Nd/144Nd ratios of lavas erupted through the Andean Plateau are distinctly crustal (>0.705 and <0.5125, respectively) and can be used as a plateau discriminant. These relationships are used to constrain 200 Myr of surface uplift history for the Western Cordillera (present elevation 4200±516 m). Jurassic-Paleogene isotope compositions (including new Paleogene analyses) became gradually more ‘crust-like’ over time, yet the distinct isotope signatures relating to the Andean Plateau were not achieved until the Miocene (23 Ma). Results support the slow and steady surface uplift model, synchronous with gradual crustal shortening and thickening. The isotope paleo-elevation model predicts that current elevations were attained in the Western Cordillera by 23 Ma. From 23-10 Ma, both deformation and surface uplift gradually propagated southwards by ~400 km

Response of saline reservoir to different phaseCO₂-brine: experimental tests and image-based modelling

Geological CO₂ storage in saline rocks is a promising method for meeting the target of net zero emission and minimizing the anthropogenic CO₂ emitted into the earth’s atmosphere. Storage of CO₂ in saline rocks triggers CO₂-brine-rock interaction that alters the properties of the rock. Properties of rocks are very crucial for the integrity and efficiency of the storage process. Changes in properties of the reservoir rocks due to CO₂-brine-rock interaction must be well predicted, as some changes can reduce the storage integrity of the reservoir. Considering the thermodynamics, phase behavior, solubility of CO₂ in brine, and the variable pressure-temperature conditions of the reservoir, there will be undissolved CO₂ in a CO₂ storage reservoir alongside the brine for a long time, and there is a potential for phase evolution of the undissolved CO₂. The phase of CO₂ influence the CO₂-brine-rock interaction, different phaseCO₂-brine have a unique effect on the properties of the reservoir rocks, Therefore, this study evaluates the effect of four different phaseCO₂-brine reservoir states on the properties of reservoir rocks using experimental and image-based approach. Samples were saturated with the different phaseCO₂-brine, then subjected to reservoir conditions in a triaxial compression test. The representative element volume (REV)/representative element area (REA) for the rock samples was determined from processed digital images, and rock properties were evaluated using digital rock physics and rock image analysis techniques. This research has evaluated the effect of different phaseCO₂-brine on deformation rate and deformation behavior, bulk modulus, compressibility, strength, and stiffness as well as porosity and permeability of sample reservoir rocks. Changes in pore geometry properties, porosity, and permeability of the rocks in CO₂ storage conditions with different phaseCO₂-brine have been evaluated using digital rock physics techniques. Microscopic rock image analysis has been applied to provide evidence of changes in micro-fabric, the topology of minerals, and elemental composition of minerals in saline rocks resulting from different phaseCO₂-br that can exist in a saline CO₂ storage reservoir. It was seen that the properties of the reservoir that are most affected by the scCO₂-br state of the reservoir include secondary fatigue rate, bulk modulus, shear strength, change in the topology of minerals after saturation as well as change in shape and flatness of pore surfaces. The properties of the reservoir that is most affected by the gCO₂-br state of the reservoir include primary fatigue rate, change in permeability due to stress, change in porosity due to stress, and change topology of minerals due to stress. For all samples, the roundness and smoothness of grains as well as smoothness of pores increased after compression while the roundness of pores decreased. Change in elemental composition in rock minerals in CO₂-brine-rock interaction was seen to depend on the reactivity of the mineral with CO₂ and/or brine and the presence of brine accelerates such change. Carbon, oxygen, and silicon can be used as index minerals for elemental changes in a CO₂-brine-rock system. The result of this work can be applied to predicting the effect the different possible phases of CO₂ will have on the deformation, geomechanics indices, and storage integrity of giant CO₂ storage fields such as Sleipner, In Salah, etc

THE INFLUENCE OF LANDSCAPE STRUCTURE ON STORAGE AND STREAMFLOW GENERATION IN A PIEDMONT CATCHMENT

The storage of water and generation of streamflow are fundamental catchment functions. The specific way in which a catchment performs these functions is inextricably tied to the structure of the catchment, including the thickness/texture of soil, depth to impermeable bedrock, and presence of riparian areas with shallow water tables. Accordingly, catchments with different landscape structures will respond differently to hydroclimatic variability. The majority of field investigations into streamflow generation have concentrated on high relief or recently glaciated landscapes where soils are thin and overlie an assumed impermeable bedrock layer. In contrast, relatively little research on streamflow generation has been conducted in deeply weathered regions, such as in the Piedmont Physiographic Province of the eastern United States. Of those studies that have focused on these regions, many have highlighted the potential of deeply weathered landscapes to store large quantities of water, which may be important for maintaining streamflow during droughts. In the research effort reported here, catchment storage and streamflow generation in a prototypical Piedmont headwater catchment were investigated through field data collection and modeling. The analysis aimed to test hypotheses relating hydrologic function to Piedmont landscape structure. The 37-hectare, forested Pond Branch Catchment of northern Maryland was instrumented to collect data on hillslope spring discharge, hydrometeorological data, riparian well water levels, as well as three years of high frequency precipitation and streamflow stable water isotope data. Additional data were collated from other sources on catchment discharge, soil moisture, and remotely-sensed land surface properties. These data were used in combination with recession analysis, water balance models, and transport modeling using StorAge Selection functions to estimate storage and characterize streamflow generation. The storage within the hillslope and underlying weathered bedrock was found to be the main driver of the slowly changing baseflow component of streamflow, which made up 85% of total discharge. In addition, the rapidly responding quickflow component of streamflow was proven to be composed of a combination of direct precipitation and return flow from the toe of the hillslope, which was generated as saturation excess overland flow at the riparian-hillslope boundary. The importance of the storage structure in controlling the emergent catchment response to precipitation variability was revealed when a relatively small reduction in rainfall during early spring (when the deep flow system is typically recharged) of water year 2016 produced what may be a decadal drought in the groundwater level, resulting in persistently low baseflow discharge for at least two years after. The role of the deeply weathered landscape structure of Pond Branch in controlling storage and streamflow generation highlights the importance of studying diverse landscapes with different landscape structures in order to gain understanding into catchment functions

“TEACHING REAL NUMBERS IN THE HIGH SCHOOL: AN ONTO-SEMIOTIC APPROACH TO THE INVESTIGATION AND EVALUATION OF THE TEACHERS' DECLARED CHOICES”

The thesis addresses the topics of investigating teachers' declared choices of practices concerning real numbers and the continuum in the high school in Italy, evaluating their didactical suitability and the impact of a deep reflexion about some historical and didactical issues on the teachers' decision-making process. Our research hypothesis was that teachers' choices of teaching sequences concerning real numbers, with particular attention to the representations of real numbers, could be very relevant in order to interpret some of the well-known students' difficulties. After a pilot study in form of a teaching experiment and a literature review concerning students' and teachers' difficulties with real numbers and the continuum, we observed that some causes of potential difficulties could be situated indeed in the very beginning of the teaching-learning process, even before entering the classrooms: the phase in which a teacher choose the practices and objects by means of whom introducing and work with real numbers and the continuum. In particular the choice of the objects involved in the practice seemed to be relevant, since every object emerge from previous practices and its meaning is identified by the practices in which it emerged. Thus we got interested in investigating the personal factors that affect the process of selection of practices: personal meaning, goals and orientations, as it was stressed by Schoenfeold in his goal-oriented decision-making approach to the analysis of teachers choices. Furthermore we decided to explore the teachers' choices of sequences of practices and of representation of the mathematical objects and then to evaluate their suitability in relation to the literature review concerning students' difficulties with real numbers and to the complexity of the mathematical object as it emerge from an historical analysis. After having analysed the theoretical frameworks in mathematics education that could permit us to carry out our research, we decided to use the OSA, (onto-semiotioc approach) elaborated by Godino, Batanero & Font, described in their paper in 2007, and some evolutions like the CDM (conoscimiento didactico matematico) model proposed by Godino in 2009. We evaluated also other frameworks, in particular the ATD (Chevallard, 2014), but we found the OSA better for the analysis we would like to carry out. In particular the operationalization of the methodologies of analysis of the teachers' personal meaning of mathematical objects and the construct of didactical suitability were more effective for our porpouses. Our main results are the following: mny teachers' personal meanings of real numbers are far from the epistemic one; many of the teachers who studied real numbers at a formal level at school and at the University and perceived them as difficult and unuseful try to avoid to deepen the issues concerning real numbers with their stundent, thinking they would not understand; in general the experiences as students affect the teachers' choices; the teachers usually refer to real numbers also when the meaning is partial and doesn't coincide with one of the most general epistemic meanings of real numbers; very few teachers are aware of the complexity of the real numbers and are as aware of it to be able to control the relations between their many facets; also the teachers with a PhD in Mathematics operate choices that we can evaluate as unsuitable standing on the literature review and our framework; the teacher consider very hard to work with discrete and dense sets and prefer the intuitive approach to continuous sets rather then deepen the relation between dense and continuous sets, different degrees of infinity and so on; some teachers reasoning during the interviews changed their mind, getting aware of the complexity and admitting that simplifying too much can constitute a further cause of difficulty; the teachers refer to the students difficulties to justify their choice of simplifying, but when they face some crucial issues, often they admit to consider them unuseful or too difficult; nevertheless no teachers declare that would renounce to introduce the field of real numbers, at least intuitively; the most of the teachers declare that nothing more is introduced about real numbers in the last years and that the partial meanings introduced in the first years are used to face the Calculus problems (intuItive approach to the Calculus); all the teachers consider necessary to introduce R or adequate subsets of R as domains of the functions expressed analytically because of their continuous graphic.The thesis addresses the topics of investigating teachers' declared choices of practices concerning real numbers and the continuum in the high school in Italy, evaluating their didactical suitability and the impact of a deep reflexion about some historical and didactical issues on the teachers' decision-making process. Our research hypothesis was that teachers' choices of teaching sequences concerning real numbers, with particular attention to the representations of real numbers, could be very relevant in order to interpret some of the well-known students' difficulties. After a pilot study in form of a teaching experiment and a literature review concerning students' and teachers' difficulties with real numbers and the continuum, we observed that some causes of potential difficulties could be situated indeed in the very beginning of the teaching-learning process, even before entering the classrooms: the phase in which a teacher choose the practices and objects by means of whom introducing and work with real numbers and the continuum. In particular the choice of the objects involved in the practice seemed to be relevant, since every object emerge from previous practices and its meaning is identified by the practices in which it emerged. Thus we got interested in investigating the personal factors that affect the process of selection of practices: personal meaning, goals and orientations, as it was stressed by Schoenfeold in his goal-oriented decision-making approach to the analysis of teachers choices. Furthermore we decided to explore the teachers' choices of sequences of practices and of representation of the mathematical objects and then to evaluate their suitability in relation to the literature review concerning students' difficulties with real numbers and to the complexity of the mathematical object as it emerge from an historical analysis. After having analysed the theoretical frameworks in mathematics education that could permit us to carry out our research, we decided to use the OSA, (onto-semiotioc approach) elaborated by Godino, Batanero & Font, described in their paper in 2007, and some evolutions like the CDM (conoscimiento didactico matematico) model proposed by Godino in 2009. We evaluated also other frameworks, in particular the ATD (Chevallard, 2014), but we found the OSA better for the analysis we would like to carry out. In particular the operationalization of the methodologies of analysis of the teachers' personal meaning of mathematical objects and the construct of didactical suitability were more effective for our porpouses. Our main results are the following: mny teachers' personal meanings of real numbers are far from the epistemic one; many of the teachers who studied real numbers at a formal level at school and at the University and perceived them as difficult and unuseful try to avoid to deepen the issues concerning real numbers with their stundent, thinking they would not understand; in general the experiences as students affect the teachers' choices; the teachers usually refer to real numbers also when the meaning is partial and doesn't coincide with one of the most general epistemic meanings of real numbers; very few teachers are aware of the complexity of the real numbers and are as aware of it to be able to control the relations between their many facets; also the teachers with a PhD in Mathematics operate choices that we can evaluate as unsuitable standing on the literature review and our framework; the teacher consider very hard to work with discrete and dense sets and prefer the intuitive approach to continuous sets rather then deepen the relation between dense and continuous sets, different degrees of infinity and so on; some teachers reasoning during the interviews changed their mind, getting aware of the complexity and admitting that simplifying too much can constitute a further cause of difficulty; the teachers refer to the students difficulties to justify their choice of simplifying, but when they face some crucial issues, often they admit to consider them unuseful or too difficult; nevertheless no teachers declare that would renounce to introduce the field of real numbers, at least intuitively; the most of the teachers declare that nothing more is introduced about real numbers in the last years and that the partial meanings introduced in the first years are used to face the Calculus problems (intutive approach to the Calculus); all the teachers consider necessary to introduce R or adequate subsets of R as domains of the functions expressed analytically because of their continuous graphic

Popularization of mathematics as intercultural communication : an exploratory study

Popularization of mathematics seems to have gained importance in the past decades. Besides the increasing number of popular books and lectures, there are national and international initiatives, usually supported by mathematical societies, to popularize mathematics. Despite this apparent attention towards it, studying popularization has not become an object of research; little is known about how popularizers choose the mathematical content of popularization, what means they use to communicate it, and how their audiences interpret popularized mathematics. This thesis presents a framework for studying popularization of mathematics and intends to investigate various questions related to the phenomenon, such as: - What are the institutional characteristics of popularization? - What are the characteristics of the mathematical content chosen to be popularized? - What are the means used by popularizers to communicate mathematical ideas? - Who are the popularizers and what do they think about popularization? - Who are the audience members of a popularization event? - How do audience members interpret popularization? The thesis presents methodological challenges of studying popularization and suggests some ideas on the methods that might be appropriate for further studies. Thus it intends to offer a first step for developing suitable means for studying popularization of mathematics