127 research outputs found
Generalized diagnostic scaling for high-order moments in turbulent boundary layers
No full textThe present work builds upon the diagnostic plot for the streamwise turbulence intensity [Alfredsson & Örlü, 2010] and generalises it for higher-order (even and odd) moments providing a general description of the probability density distribution of streamwise velocity fluctuations. Turbulent boundary layers (up to a friction Reynolds number of 20'000) are employed and demonstrate its feasibility to scale data throughout the overlap and outer region
Stereoscopic PIV measurement in laminar rotating plane Couette flow
No full textPlane Couette flow with spanwise system rotation shows structures of streamwise-oriented roll cells that arise due to the instability by the Coriolis force when the system rotation is in the opposite direction to the mean flow vorticity. The momentum transport caused by such roll cell structures makes the flow tend to exhibit zero absolute vorticity. In the present study, stereoscopic PIV measurements in the rotating plane Couette flow were carried out in order to further illuminate the vortex structures and transport phenomena in this flow. The Reynolds stresses and some terms of its transport equation were evaluated to discuss the transport phenomena caused by the coherent structure. Furthermore, the wall shear stress was evaluated based on the measurement results of the Reynolds and viscous shear stresses and its variation with the system rotation rate is also presented
A Changed Leadership? : A study of the EU leadership from a instituional standpoint, related to multilateral environmental negotiations
No full textAbstract Political Science, level III thesis Spring semester 2010 Author: Emelie Alfredsson Supervisor: Tomas Mitander "A Changed Leadership? - A study of the EU leadership from a institutional standpoint, related to multilateral environmental negotiations" The EU has for a relatively long time considered itself a leader in the environmental policy area as a whole as well as in multilateral environmental negotiations. This study attempts to classify and identify the European leadership with the purpose of relating it to the institutional framework of the Union. The treaties of the European Union decide its ability to act and its institutions the right to engage in different policy areas, the environmental area being the focus of this study. With the recent ratification of the Lisbon treaty this study aims to make out if the type of leadership the Union showed during the Kyoto negotiations has changed with the new treaty, into a new type during the COP-15 meeting in Copenhagen. The results shows that the Union has kept the same type of leadership despite the change in treaties, though with great potential of changing leadership if or when the new reforms of the new treaty are better implemented. This result points to the fact that institutional changes have a small effect on the EU leadership and that other factors such as ability to unite the member countries may play a bigger role. Keywords: EU, leadership, multilateral environmental negotiations, Copenhagen, Kyot
Molecular Studies of Mast Cell Migration and Apoptosis : Two Ways of Regulating Mast Cell Numbers at Sites of Inflammation
No full textUpon activation mast cells release numerous proinflammatory mediators. With this feature, mast cells play an important role in host defense against pathogens, and are involved in tissue remodeling and wound healing. However, in cases of excessive inflammation the effects of mast cells are detrimental. This is observed in allergy, asthma, rheumatoid arthritis, atherosclerosis, certain types of heart failure, and in several other chronic destructive inflammations. Mast cell numbers are typically increased at inflammatory sites. There they act both directly, as effector cells, and in a regulatory manner, secreting agents that recruit and activate other immune cells. The studies presented here investigated mechanisms regulating mast cell numbers at sites of inflammation, focusing on cell migration and regulation of survival/apoptosis. We report that SCF-induced mast cell migration requires p38 MAP kinase activity. Moreover, we found that SCF-mediated mast cell survival is regulated through downregulation of the proapoptotic Bcl-2 family member Bim, as well as through phoshorylation of Bim. SCF seems to control Bim protein levels via FOXO transcription factors, and to induce phosphorylation of Bim via the Mek/Erk and the PI3-kinase/Akt signaling pathways. Furthermore, mast cell death triggered by deprivation of SCF and/or IL-3 involves the Bim protein, as demonstrated using bim-/- mast cells. Additional studies revealed that IgE-receptor activation, which occurs in allergy, promotes both prosurvival and proapoptotic signaling events. This includes upregulation of Bim and the prosurvival Bcl-XL and A1, as well as phosphorylation of Akt, FOXO factors, GSK-3β, IκB-α, Bad, and Bim. The simultaneous stimulation of prosurvival and proapoptotic signaling events could be a way to fine-tune the fate of mast cells after IgE-receptor activation and degranulation. The new insights about mechanisms involved in mast cell migration and regulation of survival/apoptosis might prove useful for future efforts to design new drugs to be used for mast cell-associated diseases
INNOVATIVE TOOL-MODIFICATIONS AND TOOL SELECTIVITY IN NEW CALEDONIAN CROWS (CORVUS MONEDULOIDES)
No full textTool-use and tool-manufacture are thought to require high cognitive skills and have been considered as an exclusive attribute to primates. Recent observations of New Caledonian crows (NCCs) challenge this assumption. In this study 13 NCCs were tested with two different tool production tasks. The NCC either had to straighten a hook or bend a stick to retrieve food from two different kinds of tree trunks. The result showed that 3/5 birds bent sticks and used them to retrieve food and 1/5 birds straightened hooks to retrieve food. The birds managed to solve both tasks but not the birds in the control group. This indicates that NCC's tool making is a flexible innovative act and not just an innate predisposition to bend flexible material. This finding is interesting given that recent studies on human children show that below 8 years of age children fail in similar innovative tool making tasks
Infections, antibiotics, tobacco, genetic factors and risk of lada : latent autoimmune diabetes in adults, and type 2 diabetes
No full textDiabetes is a spectrum of chronic diseases characterized by hyperglycaemia. The aetiology and pathogenesis differ between types of diabetes, but all can lead to severe complications. Latent autoimmune diabetes in adults (LADA) is the most prevalent type of autoimmune diabetes with onset in adulthood, yet risk factors are largely unknown. Therefore, this thesis was devoted to the study of potential risk factors for LADA compared to type 2 diabetes.The Swedish Epidemiological Study of Risk Factors for LADA and type 2 diabetes (ESTRID) constituted the foundation of the four studies in this thesis. ESTRID is a case-control study with incident cases of LADA and type 2 diabetes along with control participants from the general population. Study I, II, and IV were complemented with incident cases of LADA and type 2 diabetes as well as diabetes-free individuals from the Norwegian cohort study HUNT. Study I and II investigated the role of tobacco use and genetic susceptibility for the risk of LADA, using data from ESTRID and HUNT. These analyses were supported by Mendelian randomization studies based on data from genome-wide association studies. In Study III and IV, data from national and regional health registers were linked to ESTRID and HUNT to investigate the association between LADA and prior infections and antibiotic exposure. Results for LADA were compared to those for type 2 diabetes in all four studies.We found that smoking increases the risk of LADA, particularly in those with genetic susceptibility conferred by risk genes associated with autoimmunity, type 2 diabetes, or insulin resistance. The increased risk of LADA and type 2 diabetes in smokers seen in the observational data was confirmed in the Mendelian randomization studies. In contrast, no increased risk of LADA was observed with infections or antibiotic exposure up to 10 years prior to diagnosis, neither in those with high genetic risk nor in those with low-moderate risk. Instead, a reduced risk associated with antibiotic exposure 6-10 years prior to diagnosis was observed.In conclusion, tobacco use, which is associated with type 2 diabetes and insulin resistance, seems to increase the risk of LADA. Genetic susceptibility plays a role by aggravating these associations. However, infections and antibiotic exposure, previously linked to type 1 diabetes, were not associated with LADA. Further studies are needed to confirm these results, particularly the finding of a reduced risk of LADA with prior exposure to antibiotics.List of scientific papersI. Edstorp, J., Wei, Y., Ahlqvist, E., Alfredsson, L., Grill, V., Groop, L., Carlsson, S. (2023). Smoking, use of smokeless tobacco, HLA genotypes and incidence of latent autoimmune diabetes in adults. Diabetologia. 66(1), 70-81. doi:10.1007/s00125-022-05763-w. https://doi.org/10.1007/s00125-022-05763-w II. Edstorp, J., Ahlqvist, E., Alfredsson, L., Mansour Aly, D., Grill, V., Rasouli, B., Carlsson, S. (2023). Incidence of LADA and Type 2 Diabetes in Relation to Tobacco Use and Genetic Susceptibility to Type 2 Diabetes and Related Traits: Findings From a Swedish Case-Control Study and the Norwegian HUNT Study. Diabetes Care. 46(5), 1028-1036. doi:10.2337/dc22-2284. https://doi.org/10.2337/dc22-2284 III. Edstorp, J., Rossides, M., Ahlqvist, E., Rasouli, B., Tuomi, T., & Carlsson, S. (2024). Does a prior diagnosis of infectious disease confer an increased risk of latent autoimmune diabetes in adults? Diabetes Metab Res Rev. 40(3), e3758. doi:10.1002/dmrr.3758. https://doi.org/10.1002/dmrr.3758 IV. Edstorp, J., Rossides, M., Ahlqvist, E., Alfredsson, L., Askling, J., Di Giuseppe, D., Carlsson, S. Exposure to antibiotics and the risk of latent autoimmune diabetes in adults and type 2 diabetes - results from a Swedish case-control study and the Norwegian HUNT study. [Manuscript]</p
IgE-receptor activation of mast cells regulates phosphorylation and expression of forkhead and Bcl-2 family members
No full textEVERY Word should Do a Full Time Job – the Politics of Maximalism, DJ:ism, and Lars-Mikael Raattamaa
No full textThis paper is an attempt to take into joint account Jacques Rancière’s take on “politics” as a heterogeneous force, and Gilles Deleuze’s and Felix Guattari’s concept of “becoming”, when approaching contemporary avant-garde poetry. It could be argued that such an operation runs the risk of being self-confirming, or circular, due to the fact that the ideas of an ideal heterogeneity that permeate both these theoretical concepts also does play a vital part in the political avant-garde of the day. This risk might also be why such ventures are so rare. However, that particular line of argument could of course be reversed, just as well. If contemporary avant-garde, on the one hand, and critical theory, on the other, share certain basic assumptions, why should the relation between the two not be examined more closely? In this paper I will examine how Swedish contemporary poet Lars-Mikael Raattamaa, in his book Mallamerik, mallammer, malameri, mallame, amerik, mallameka, merrika…, attempts a move away from conventional poetic form. This attempt is in many ways analogical to how “the political” according to Rancière moves away from “polis”, and how the “becoming” (and related concepts in the writings of Deleuze/Guattari, like “nomadic”, “de-territorialisation”, “flesh”, “the molecular”, “the rhizom”) moves away from form and stability. This particular Raattamaa-book employs a poetics which could be described in terms of “maximalism”. More specifically, a modus of the DJ is used in order to create a kind of heterogeneous flow. Within this flow, certain conventional literary cue points, such as punctuation, syntax, author, are questioned, at least symbolically. Through text-strategies that could be labelled “maximalist”, or “political”, or “becoming”, Raattamaa performs a severe critique of the supposedly stable hierarchies of conventional poetic language, i.e. the “polis” (Rancière), or the “body” (Deleuze/Guattari)
Web Experience in Mobile Networks: Lessons from Two Million Page Visits
No full textMeasuring and characterizing web page performance is a challenging task.
When it comes to the mobile world, the highly varying technology characteristics coupled with the opaque network configuration make it even more difficult.
Aiming at reproducibility, we present a large scale measurements study of web page performance collected in eleven commercial mobile networks spanning four countries.
We build a dataset of nearly two million web browsing sessions to we shed light on the impact of different web protocols, browsers, and mobile technologies on the web performance.
We find that the impact of mobile broadband access is sizeable.
For example, the median page load time using mobile broadband increases by a third compared to wired access.
Mobility clearly stresses the system, with handover causing the most evident performance penalties.
Contrariwise, our measurements show that the adoption of HTTP/2 and QUIC has practically negligible impact.
Our work highlights the importance of large-scale measurements.
Even with our controlled setup, the complexity of the mobile web ecosystem is challenging to untangle.
For this, we are releasing the dataset as open data for validation and further research.
We also release together with the datasets we collected the scripts we use to produce the analysis we present in the paper. Please use plot_all.sh script to generate the plots in the paper, using the separate scripts from the "scripts" archive.
Should you use any of these resources, please also make an attribution using the following reference (provided here in bibtex format):
@inproceedings{rajiullah2019web,
title={{Web Experience in Mobile Networks: Lessons from Two Million Page Visits}},
author={Rajiullah, Mohammad and Lutu, Andra and Khatouni, Ali Safari and Fida, Mah-Rukh and Mellia, Marco and Brunstrom, Anna and Alay, Ozgu and Alfredsson, Stefan and Mancuso, Vincenzo},
booktitle={The World Wide Web Conference},
pages={1532--1543},
year={2019},
organization={ACM},
address = {San Francisco, CA, USA},
keywords = {Web Experience, HTTP2, QUIC, TCP, Mobile Broadband, Measurements}
}</pre
Molecular Studies of Mast Cell Migration and Apoptosis [Elektronisk resurs] : Two Ways of Regulating Mast Cell Numbers at Sites of Inflammation
No full textUpon activation mast cells release numerous proinflammatory mediators. With this feature, mast cells play an important role in host defense against pathogens, and are involved in tissue remodeling and wound healing. However, in cases of excessive inflammation the effects of mast cells are detrimental. This is observed in allergy, asthma, rheumatoid arthritis, atherosclerosis, certain types of heart failure, and in several other chronic destructive inflammations. Mast cell numbers are typically increased at inflammatory sites. There they act both directly, as effector cells, and in a regulatory manner, secreting agents that recruit and activate other immune cells.The studies presented here investigated mechanisms regulating mast cell numbers at sites of inflammation, focusing on cell migration and regulation of survival/apoptosis. We report that SCF-induced mast cell migration requires p38 MAP kinase activity. Moreover, we found that SCF-mediated mast cell survival is regulated through downregulation of the proapoptotic Bcl-2 family member Bim, as well as through phoshorylation of Bim. SCF seems to control Bim protein levels via FOXO transcription factors, and to induce phosphorylation of Bim via the Mek/Erk and the PI3-kinase/Akt signaling pathways. Furthermore, mast cell death triggered by deprivation of SCF and/or IL-3 involves the Bim protein, as demonstrated using bim-/- mast cells. Additional studies revealed that IgE-receptor activation, which occurs in allergy, promotes both prosurvival and proapoptotic signaling events. This includes upregulation of Bim and the prosurvival Bcl-XL and A1, as well as phosphorylation of Akt, FOXO factors, GSK-3β, IκB-α, Bad, and Bim. The simultaneous stimulation of prosurvival and proapoptotic signaling events could be a way to fine-tune the fate of mast cells after IgE-receptor activation and degranulation.The new insights about mechanisms involved in mast cell migration and regulation of survival/apoptosis might prove useful for future efforts to design new drugs to be used for mast cell-associated diseases.</p
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