Poissonian bursts in e-mail correspondence

Recent work has shown that the distribution of inter-event times for e-mail communication exhibits a heavy tail which is statistically consistent with a cascading Poisson process. In this work we extend the analysis to higher-order statistics, using the Fano and Allan factors to quantify the extent to which the empirical data depart from the known correlations of Poissonian statistics. The analysis shows that the higher-order statistics from the empirical data is indistinguishable from that of randomly reordered time series, thus demonstrating that e-mail correspondence is no more bursty or correlated than a Poisson process. Furthermore synthetic data sets generated by a cascading Poisson process replicate the burstiness and correlations observed in the empirical data. Finally, a simple rescaling analysis using the best-estimate rate of activity, confirms that the empirically observed correlations arise from a non-homogeneus Poisson process

Foraging under conditions of short-term exploitative competition: The case of stock traders

Theory purports that animal foraging choices evolve to maximize returns, such as net energy intake. Empirical research in both human and nonhuman animals reveals that individuals often attend to the foraging choices of their competitors while making their own foraging choices. Due to the complications of gathering field data or constructing experiments, however, broad facts relating theoretically optimal and empirically realized foraging choices are only now emerging. Here, we analyze foraging choices of a cohort of professional day traders who must choose between trading the same stock multiple times in a row---patch exploitation---or switching to a different stock---patch exploration---with potentially higher returns. We measure the difference between a trader's resource intake and the competitors' expected intake within a short period of time---a difference we call short-term comparative returns. We find that traders' choices can be explained by foraging heuristics that maximize their daily short-term comparative returns. However, we find no one-best relationship between different trading choices and net income intake. This suggests that traders' choices can be short-term win oriented and, paradoxically, maybe maladaptive for absolute market returns

Towards sustainable shipping: Evaluating the environmental impact of electrofuels

The global, local, and regional environment is under pressure from human activity. Changes in the environment can be beneficial and strived for, but environmental and health problems need to be considered when we design human activities. Shipping is a human activity causing emissions to air, water, and soil, which has direct and indirect effects on the environment. New fuels and propulsion technologies are required to lower the emissions from the shipping sector and reduce the impact on, for example, climate change. Fuels produced through electricity, water, and carbon dioxide, so-called electrofuels, is one group of fuels suggested to reduce the climate impact of shipping. This thesis focuses on the emissions from ships and their impacts on the environment when vessels move to electrofuels.This licentiate thesis aims to study the potential impact on the natural environment from using electrofuels onboard vessels and to explore which factors act as the main influencers on the natural environment and human health. Life cycle assessment was selected to address these questions, and through case study application the first assessment of an electrofuel in the context of shipping was performed. Through a techno-environmental system approach, critical flows between the shipping fuel life cycle and the environment were identified.The result points towards reductions of climate change impacts if renewable energy is used and CO2 is captured from a source not acting as a driver of fossil fuel extraction. Potential trade-offs were identified as electrofuels could lead to higher pressure on human health than today’s conventional fuels. The extent of these trade-offs is uncertain and affected by limitations in the method approach to the life cycle assessment of marine fuels. Suggestions on how to address these uncertainties, such as detailed system boundary definitions, are brought forward and analyzed based on the current state-of-the-art. The findings discussed in this licentiate thesis aim to promote further discussion around how to assess emerging fuel and propulsion technologies and the potential impact of future marine fuels

Evaluation of UHT milk processed by direct steam injection and steam infusion technology

UHT direct steam injection and steam infusion are widely used; however there is no comparison of their impact on milk components. This study evaluates the structural changes at different steps during the UHT processing of whole milk in a full-scale UHT plant by transmission electron microscopy (TEM) and particle size measurements, and follows the enzymatic activity. The results of structural analyses by TEM show the formation of agglomerates during the final heating step using both technologies; however in samples from steam injection, the agglomerates were larger and more frequent. Regardless of the heating system, big agglomerates were still present after the vacuum cooling, but very rarely in the final product. The creation of big protein agglomerates in the milk from steam injection could be a result of the accumulation of proteins on the surface of steam bubbles formed during the introduction of steam into the product and may influence its stability at the early stage of storage (Paper II.). Sedimentation was the only parameter significantly dependent on the final heating technology and preheating temperature. The amount of sediment was significantly higher in milk processed by steam injection and when preheated to 75ºC compared to 80ºC. Sediment in all samples contained large protein particles, some of them containing fat globule agglomerates covered by a thick protein layer (Paper III.). The casein micelles in milk stored at 5ºC, 22ºC and 30ºC had an irregular surface that reduced in size on storage while tendrils became extended. These structural changes led to gelation within four or five months? storage at 22ºC and 30ºC. At 40ºC the tendrils dissociated and the samples never gelled. The absence of gel formation could be a combined effect of plasmin activity and lactosylation (Paper III.). The volume-weighted mean diameter of casein micelles in samples produced by steam infusion was larger than in samples from steam injection. This could be explained by the b-lactoglobulin/?-casein complex being better anchored to the casein micelle surface than in samples from steam injection, where the complex was released to a greater extent or mechanical damage of casein micelles during steam injection leading to micelle disintegration and disaggregation (Paper III.). The structural changes and localization of the individual proteins in UHT milk kept at 22ºC or 40ºC for 6 months were followed using transmission electron microscopy combined with immunogold labelling on total caseins, ?-casein and ?-lactoglobulins A and B. In the freshly produced UHT milk, the labelling of total casein concentrated mainly on the micelles, while ?-lactoglobulin and ?-casein were localized in the serum phase and on the micelle surface. In the stored samples, tendrils protruding from the micelles showed positive labelling against all the analyzed proteins. The heavy particles that sedimented after 6 months storage showed positive labelling for total casein but not for ?-casein suggesting that the sediment composition based on caseins was most probably the hydrophobic parts of the casein micelles or protein fragments from proteolyses by plasmin (Paper IV). The enzymatic activity was the same in milk produced in both systems; however the sedimentation rate was greater in samples treated with steam injection. Based on that, we can say that analyses of results of proteolytic action measured by capillary electrophoresis of supernatant cannot alone be used for predicting the shelf life or stability of UHT milk (Paper I.). Plasmin activity was negligible at 5ºC, increased with temperature at 22ºC and 30ºC, but decreased at 40ºC. Gel formation occurred in samples stored at 22ºC and 30ºC, but not at 5ºC and 40ºC. Lactosylation started at 22ºC and increased with increasing storage temperature. After 6 months storage at 40ºC, all ?-lactoglobulin molecules contained at least 2 lactose residues, and the proteose-peptones were also lactosylated. The extensive lactosylation at 40ºC may play an important role in the absence of gelation. Destabilization of casein micelles and restructuring of proteins have a huge impact on both sediment and gel formation (Paper I.)

Customization of buildings using configuration systems - a study of conditions and opportunities in the Swedish timber house manufacturing industry

The aim of this project has been to study timber house manufacturers and provide guidance to those who aim to increase efficiency through the adaption of product modeling and eventually configuration. The findings in this report are based on a series of case studies within the abovementioned industry, which serves as a basis for the analysis and recommendations given. The Swedish timber house manufacturing industry has a long tradition of producing houses in factories. In recent years, however, the construction industry has received criticisms for issues with quality and productivity, problems that is also valid for the timber house manufacturers. During the upswing in the past decade, IT investments in the industry have not kept the same pace as other investments. For this reason IT environments are currently growing out of date, which is one reason contributing to today’s problems. In many ways the timber house manufacturers resembles traditional on-site construction, especially in how they use IT and product documentation. Given the different conditions in the industries and the fact that timber house manufacturers can assimilate influences from other manufacturing industries, this presents an interesting opportunity to pursue for the industry. The results from the case studies show that companies have a potential to better integrate processes, use IT and manage product documentation. How timber house manufacturers view themselves also affects how they treat questions regarding abovementioned areas, which ultimately also affects how well they will be able to use configuration. Whether they see themselves as a construction company, an engineering firm or a manufacturing industry will have an effect on many aspects of how to run the business. The findings show that the timber house manufacturing companies has a potential in streamlining and standardizing product documentation to facilitate configuration and improving the product specification process. Companies should address three areas as a part of the change: processes, IT and product documentation. When considering these three areas together, companies have an opportunity to increase their competitiveness through more efficient processes and standardized product families. Clearly there are risks associated with introducing new IT systems and changing processes. Companies need to consider the risks and potential benefits with pursuing this path. Risks that should be included in an evaluation are for example; changes in the market, costs and quantifiable benefits from using configuration. The report provides a number of advices to the timber house manufacturers that might be useful to consider for companies that wishes to go forward with product modeling and configuration. For example, it is recommended that companies investigate how to define the roles and responsibilities of the Chief Information Officer and Chief Technology Officer, explore how the IT-strategy best delivers value to the business and consider to introduce a product development process

Industrialized construction - explorations of current practice and opportunities

Industrialized construction has over the years taken different expressions and gone through different phases depending on where inspiration has come from. In this project, industrialized construction has been studied in two applications: timber house manufacturing and renovation of multi-family houses. In Sweden industrialized production of timber houses is relatively strong in the housing sector, it however resides somewhere between industrial production and the traditional construction sector, which has led to some ambivalence. IT support and product documentation largely reflects the traditional construction sector, which means that they find it difficult to use the potential of industrialized construction in full. The efficiency of production of timber houses could be improved by more effective use of IT support, as well as better coherence between internal processes and the business model. Further, they need to consider how to document products in an industrialized context. These changes will inevitably have an impact on how they are organized and would require new or changed processes. It will also have an impact on how product documentation can be used. In Sweden there are strong property owners who are able to take an active role in industrialized construction if they were provided with the right knowledge and tools. An increasingly interesting sub-sector of construction is the renovation of multi-family houses, today investment in renovation is larger than in new construction. The renovation need in multi-family houses in Sweden, as well as in the rest of Europe, is large. How it will be financed and implemented is a problem that many property owners struggle with and different strategies have been used. For example pipe renovation is a major and costly action and many buildings are in great need. Several Swedish property owners can altogether show volumes over 1000 bathrooms per year in renovation and new construction, this could justify investments in industrialized strategies. A case study company in the research project has adopted an approach that standardizes pipe renovation to a limited number of solutions. This can be seen as a first step of an industrial strategy. For further industrialization, clients need to implement a comprehensive approach to the development and standardization of solutions, as well as ensuring better control of processes for implementing pipe renovation projects. The effort to create industrialized strategies is not unattainable, but it requires investments and expertise that property owners today typically do not have. If property owners would act as concept owners for industrialized platforms for renovation and new construction, it has the potential to create a new market

Search for molecular and metabolic mechanisms contributing to impaired β-cell function

Type 2 Diabetes (T2D) prevalence is growing to pandemic proportions worldwide. The link between genotype, environment and β-cell function is still being investigated. I have devoted the work presented in this thesis to attempt to elucidate the coupling of β-cell metabolism to insulin secretion and to look for casual mechanisms underlying metabolic alterations disturbing insulin secretion. In paper I, we showed that tight coupling between glycolysis and mitochondrial metabolism is required for robust insulin secretion from β-cells by comparing two insulin secreting β-cell lines with good and poor glucose responsiveness, respectably. The cell line with poor glucose responsiveness showed increased lactate production and glycolytic flux but decreased ATP production, suggesting a disturbed coupling between glycolytic flux and mitochondrial glucose metabolism. Several metabolic genes that differed between the cell lines were found to correlate with HbA1c in human islets, reflecting long term glucose control. In paper II, a metabolic profiling analysis showed that a metabolic shift towards less glucose responsiveness and more anaerobic metabolism was characteristic for cells with poor glucosestimulated insulin secretion. Also, the hypoxia-induced transcription factor HIF-1α was found to be more stabilized in poorly responsive cells. A comparison between healthy and T2D human islets showed that this mechanism may be occurring in T2D humans as well. In paper III, we examined palmitate-induced lipotoxicity in β-cells and found that cellular stress introduced by lipotoxicity directs metabolism more towards metabolism of lipids than of glucose. Together with this, the cells exhibited poor glucose responsiveness in intracellular metabolic flux and insulin secretion. Changes in metabolic flux were accompanied by changes in gene expression and increased expression of genes in the pathways of steroid biosynthesis, cell cycle, fatty acid metabolism, DNA replication, and biosynthesis of unsaturated fatty acids. Histone-modifying enzyme activity and histone modifications on the genes Insig1, Lss, Peci, Idi1, Hmgcs1 and Casr were found to be altered in a manner consistent with gene expression. This suggests the involvement of epigenetic regulations. In conclusion, this thesis suggests that the coupling between glycolytic and mitochondrial flux is essential for the glucose sensitivity of the β-cell. Alterations in transcription factors or gene expression could be underlying disturbances of this coupling. It also shows that a diabetogenic environment with increased concentrations of fatty acids affects metabolic flux in these cells, something that is paralleled by an altered expression of metabolic genes. Finally, it suggests that epigenetic mechanisms could be involved in the regulation of these alterations

Beliefs as dispositions to make judgments

© 2023 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License.Smithies’ conception of belief has two noteworthy components: first, the claim that beliefs are fully constituted by dispositions to cause (conscious) judgments (132).2 Second, the claim that judgments have phenomenology: there's something it's like’ to make a judgment (4). Indeed, Smithies holds that judgments have both attitude- and content-specific phenomenology—that's to say that the judgment that p has a certain phenomenal character in virtue of being a judgment that p (rather than, say, a desire that p) and another, interlocking, character in virtue of being a judgment that p (rather than, say, a judgment that q). Let's label each component for easy reference: "one–track disposition": Beliefs are fully constituted by dispositions to cause judgments. "j–phenomenology": Judgments have (attitude- and content-specific) phenomenal character/s. I'll discuss both components, as well as the arguments Smithies gives in their support. It'll emerge, as we go, why this conception of belief is important to his overall project in ERO. The arguments can be divided into those that support the full conception (one–track disposition & j–phenomenology), and those that specifically support j–phenomenology. Smithies argues, first, that the conception of beliefs as one-track dispositions to make conscious judgments (best) explains the distinction between beliefs and sub-doxastic states (124–38; §2–3 below). Second, he argues, it explains Accessibilism about justification (148–52, 165–75; §4), which he thinks can be independently motivated (223 ff.). Next he argues that j–phenomenology explains phenomenal contrast cases featuring judgments (140–4; §5) as well as the ‘introspective datum’ that “we can sometimes know by introspection alone which judgments we're currently making” (145–8; §6). The best explanation of this, Smithies argues, is that judgments have phenomenal content and force. (And the best explanation of our introspective knowledge of what we believe is that beliefs are one-track dispositions to make such judgments [148].)publishedVersio