| 1. |
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| 2. |
- Ahmad, Shakeel, 1977-, et al.
(författare)
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Two-tone PLL for on-chip IP3 test
- 2010
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Ingår i: Proceedings of IEEEInternational Symposium on Circuits and Systems, (ISCAS 10). - : IEEE. - 9781424453085 ; , s. 3549-3552
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Konferensbidrag (refereegranskat)abstract
- This paper addresses a built-in-self-test (BiST) to characterize IP3 linearity of a RF receiver front-end. A two-tone stimulus is generated by a phase-lock loop (PLL) in GHz frequency range. The PLL is designed to keep the frequency difference between the two tones under control and in this way to avoid a possible injection-locking. One of the oscillation frequencies and the difference (beat) frequency can be externally controlled. According to the test requirements the phase noise and nonlinear distortion of the two-tone generator are considered as a merit for the VCO and analog adder design. A highly linear analog adder with output referred IP3 of more than +15 dBm is used to generate the RF stimulus. The two-tone power across 50 Ω receiver input impedance can be more than -25 dBm with very low intermodulation distortion of PIM3 = -75 dBc. The receiver performance is not affected significantly by the test set-up. Simulations for linearity and noise performance of the PLL designed in 65nm CMOS show sufficient potential for on-chip IP3 measurements in the GHz frequency range.
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| 3. |
- Ahmad, T, et al.
(författare)
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Diabetic osteopathy and the IGF system in the Goto-Kakizaki rat
- 2008
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Ingår i: Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society. - : Elsevier BV. - 1096-6374. ; 18:5, s. 404-411
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Aad, G., et al.
(författare)
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- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :12
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
- Krantz, Oskar, et al.
(författare)
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Use of active wheelchairs in everyday life : experiences among experienced users of active ultra lightweight rigid frame wheelchairs
- 2017
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Ingår i: Disability and Rehabilitation. - : Taylor & Francis. - 1748-3107 .- 1748-3115. ; 12:1, s. 65-72
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this study was to describe the everyday life experience of being an experienced active wheelchair user in Sweden. Method: A qualitative approach, based on interviews, was chosen. Eleven active wheelchair users were interviewed; the results analysed by means of a thematic content analysis. Results: Two main categories, each with two sub-categories emerged: (1) Challenges and changes (life-course perspective); and (2) the ambassador of differentness (activities and situations). The first sub-categories: (1a) the changing self (attitudes and values); and (1b) getting older (the meaning of experiences for future expectations). The second sub-categories: (2a) the responsible representative (having to represent a general image of disability); and (2b) other's attitudes (interactants' expressions of attitudes). Conclusions: An active wheelchair user can be seen as an open person, a representative of other wheelchair users. Interactants can actively engage in solving non-existing problems, or over-estimate actual problems, i.e. over-attentiveness. The personal experience can change over time, e.g. to care less about over-attentiveness, or to engage less in situations where over-attentiveness is likely to occur, i.e. impression management. Also, regular interactants can learn to see the wheelchair as something normal, sometimes even forgetting it.Implications for Rehabilitation To use an active wheelchair affects interaction in everyday life, rendering the user an open person, possible to address at will as a representative of other users as well. The experienced user of an active wheelchair is the expert concerning her/his present capacity in activities in everyday life; possible obstacles remain inert until defined otherwise by the user.
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| 7. |
- Eriksson, Johan, 1970-
(författare)
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Jan Anrep-Bjurlings Rättfärdiggörelse genom tro
- 1994
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Ingår i: Eidos. - Stockholm : Konstvetenskapliga institutionen, Stockholms universitet. ; 4, s. 11-12
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Recension (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Insulander, Eva, 1972-, et al.
(författare)
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Vilken kunskap erkänns i det systematiska kvalitetsarbetet? Om oförenliga tankestilar i dagens förskola
- 2014
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Ingår i: Nordisk Barnehageforskning. - : Cappelen Damm AS - Cappelen Damm Akademisk. - 1890-9167. ; 7:12, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- This study is to be seen in relation to the intensified ‘assessment culture’ that has evolved in today's educational system. The purpose is to discuss how the dualistic mission of the curriculum is being handled in preschools systematic quality work, by studying the representation and recognition of ideational and interpersonal knowledge. The study is based on video-observations of preschool teachers’ planning, work and follow up of three educational activities in two different preschools. The theoretical basis consist of a multimodal and design theoretical perspective used in combination with Ludwik Flecks work on thought styles and thought collectives. The analyse shows that the curriculum objectives are handled in contradictory ways. This is visible in interaction patterns that exhibit traces from incompatible thought styles.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Epstein, Mikael, 1940
(författare)
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Studies of Elastomer Matrix Flow Mechanisms in Nonwoven Reinforced Composites
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of this work was to develop a suitable technique for fabricating elastomer composites based on three-dimensional fibrous materials and to study the rheological behavior of matrix polymer in these structures with varied structural and fiber surface characteristics. A new type of mold was developed and tested for structural reaction injection molding (SRIM) of elastomer composites having polymer matrices made from a mixture of two components. These mixtures had short pot life and relatively high viscosity. Channel systems for polymer feeding and vacuum application were studied. The mold made possible the investigation of the mechanism of polymer matrix flow and fiber breakage during the formation of fiber-reinforced composites made of long fiber based non- woven fiber reinforcement structures. Theoretical and experimental analysis were made of the interactions between the structural parameters of the fibrous mats and the flow characteristics of the matrix with systematically varied material and process parameters. In nonwoven mats with parallel laid fibers the flow rate along the fiber direction was found to be significantly higher than the flow rate crosswise. Nonwoven mats with multidirectionally laid fibers on the other hand exhibited a radial flow pattern. The matrix flow distance was proportional to the logarithm of injection time. The decrease of pressure in the mold cavity was linearly proportional to the matrix flow distance. A method was developed to measure the adhesion between a fiber and a fast curing elastomer. Multiple droplets were formed along the length of a single fiber by following a special technique and they were then used to measure the fiber-matrix bond shear strength using the microbond pull-out method. Polyester, p-aramid, and HMW- polyethylene fibers were tested with matrix polymers of polyurethane and natural rubber latex. The effect of surface treatments including epoxyde-coating, corona, gamma-radiation, or methanol extraction on fiber-matrix adhesion was studied. Studies were made of the influence of fiber type, fiber surface properties and matrix type on some mechanical properties in elastomeric composites produced by means of SRIM and LC fabrication methods. The fibers used were PET, LLDPE and p-aramid. These fibers were treated with epoxyde, styrene and isocyanate derivatives which make the fiber surface chemically reactive. Treatments were also made with NaOH and copolymer of polyester and polyol ether, causing change in the fiber surface energy. The results show that the surface treatments which produced changes in surface energy also influenced the flow rate of matrix polymer during the composite fabrication process. The treatments resulted in chemically reactive fiber surfaces which increased the fiber-matrix bond strength but did not affect the Young's modulus of the composite material. Good correlation was found between fiber-matrix bond strength and surface energy of fiber. The dispersive component of surface energy was shown to play important role for polyurethane elastomer and surface modified PET fibers. The age of polyurethane matrix polymer has a marked influence on the bond strength. The fiber volume fraction in composites has a strong influence on the Young's modulus of the elastomer composite. A method was developed for the fabrication of elastomer composites having three- dimensional fibrous reinforcement and matrix of natural rubber. This was achieved by applying the natural rubber as a latex when mixing it with the fibers. As compared with earlier known processes, the viscosity is considerably lower thus permitting the use of long fibers in such reinforcement structures.
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| 13. |
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| 14. |
- Gallais Sérézal, Irène
(författare)
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Mechanisms of resident T cell-driven tissue responses during the onset and recurrence of human skin inflammation
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Long-lived tissue-resident memory T cells (TRM) reside in nonlymphoid organs and can drive direct cytotoxicity, focal cytokine release and potent tissue-wide anti-infectious responses upon antigenic challenge. TRM cells poised to pathogenic responses have been identified in active and resolved psoriasis and mice models of allergic contact dermatitis (ACD). It is challenging to investigate the interactions between TRM cells and the local microenvironment in human tissues, and whether these cells promote disease in the absence of circulating T cells is less studied. This thesis focuses on the functional consequences of TRM cell activation inside the skin. PAPER I: TRM cells can provide protection from infections. The retention marker CD49a was correlated to both the epidermal location of skin TRM cells and their cytotoxicity. IL-15 unleashed the killing capacities of CD8+CD103+CD49a+ T cells. The expression of CD49a in CD8+CD103+ skin T cells was associated with more IFN-γ release compared to CD8+CD103+CD49a-, which were conversely better IL-17 producers. CD49a expression delineated a CD8+ TRM cell specialization that was conserved in two inflammatory skin diseases psoriasis and vitiligo that were respectively enriched for CD8+CD103+CD49a- and CD8+CD103+CD49a+ TRM cells. PAPER II: Psoriasis is linked to overproduction of IL-17 and Type 1 interferon is implicated as a disease trigger in the early events transforming never-lesional psoriasis (NLP) into full-blown psoriasis. CCR6+CD49a- TRM cells poised towards IL-17 production were enriched in NLP, possibly due to microbe-induced epidermal chemotaxis. Activation of skin-resident T cells in NLP skin triggered Type 1 interferon tissue responses, potentially via IFN-γ-induced release of IFN-α in keratinocytes. As IFN-γ-potent TRM cells accumulate in NLP epidermis, our findings suggest that Type 1 interferon release in NLP could be driven by TRM cells. PAPER III: TRM cells poised to IL-17 and IL-22 production are retained in the epidermis in resolved psoriasis. In healthy and diseased skin, the activation of T cells within skin explants using the pan-T cell-activating antibody OKT-3 led to interferon-driven core-response CXCL10 and CXCL9 expression. Additionally, IL-17-specific transcriptional signature was induced in resolved and active psoriasis sample, and the magnitude of this response was correlated with relapse shortly upon withdrawal of UVB treatment. PAPER IV: An upregulation of S100As transcripts persisted in the long-term in the epidermis of patients with resolved allergic contact dermatitis (ACD), indicating a disease scar. While inflammatory transcripts CXCL10, GZMB, and MMP12 were normalized after antigen exclusion for two months and two years, they were quickly induced in resolved epidermis upon exposure to the allergen. MMP12 was specifically upregulated in the epidermal compartment and codes for a protein capable of degrading the collagen IV that is a constituent of the skin basement membrane. In conclusion, the TRM-driven tissue responses in human healthy and inflamed skin are highly compartmentalized and disease-specific. This concords with the functional heterogeneity of TRM cells themselves but also relies on their interplay with the stromal cells, which can help unveil pathogenic mechanisms in these relapsing-remitting inflammatory skin diseases. Preventing the TRM cell establishment or favoring their displacing by topical treatments could lead to significant improvements in the care of patients suffering from inflammatory diseases.
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| 15. |
- Joffe, Roberts
(författare)
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Durability of natural fiber composites
- 2007
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Ingår i: Conference programme & List of abstracts / International conference on innovative natural fibre composites for industrial applications. ; , s. 34-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 16. |
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| 17. |
- Obregon, Evanny, et al.
(författare)
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Is Spectrum Sharing in the Radar Bands Commercially Attractive? : A Regulatory and Business Overview
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Ingår i: Telecommunications Policy. - 0308-5961 .- 1879-3258.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The need to meet users’ expectations in the ”mobile data avalanche” represents a significant challenge for mobile networks operators (MNOs). More spectrum is a natural way to meet these requirements in a cost and time-efficient way; but new, exclusively licensed, spectrum is increasingly hard to come by. Instead, vertical spectrum sharing has been discussed as a potential solution for finding additional spectrum for mobile communications. In this paper, we focus on vertical spectrum sharing in the radar bands for providing short-range wireless access, e.g. indoors and in ”hotspots” that ”offload” mobile traffic demand. We propose a methodology for dealing with the technical, regulatory and business aspects of deploying large-scale wireless networks. Moreover, we identify the following criteria for achieving business success: spectrum availability, availability of low-cost end user devices, system scalability in terms of number of concurrently used devices and finally, the ability to guarantee a quality of service for the users.Our technical availability assessment has identified geo-location database support as necessary technical enabler and detect-and-avoid mechanism as a beneficial technical enabler for improving sharing conditions. Therefore, we propose a sharing mechanism based on three components: a central spectrum manager witha geo-location database controlling the aggregate interference, a spectrum sensing mechanism and a fast feedback between the radars and the central spectrum manager. Moreover, Licensed Shared Access (LSA) was found to be the suitable regulatory framework to support the proposed sharing mechanism and regulatory policies in real-life implementation. Our business feasibility assessment concludes that there is enough spectrum available for indoor and hotspots communication in urban areas in the radar bandsto make a large scale system commercially viable. Service quality can be guaranteedand there is a strong potential to construct low-cost devices. Uncertainties do, however, remain regarding the spectrum access cost.
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| 18. |
- An, Di, et al.
(författare)
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Additive manufacturing and characterization of complex Al2O3 parts based on a novel stereolithography method
- 2017
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Ingår i: International Journal of Applied Ceramic Technology. - : Wiley. - 1546-542X .- 1744-7402. ; 14:5, s. 836-844
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we prepared Al2O3 ceramic green parts with complex geometry and architecture using an additive manufacturing process based on stereolithography. The rheological and thermal behavior of Al2O3 slurry was firstly examined and used to establish the conditions for molding and debinding. As opposed to previous researches that only focused on manufacture techniques, the sintering behavior and densification process were systematically investigated. In addition, special attentions were paid to the evolution of microstructure between green bodies and sintered parts. The results showed that debound parts were equipped with uniform particle packing and narrow pore size distribution. The dimensions of the Al2O3 parts changed anisotropically with the different processing steps. The densification process was greatly accelerated by the decrease in pore size and annihilating of interconnected pores in which significant grain growth was observed above 1450 degrees C. The sintered part also had a homogeneous microstructure and no interface between adjacent layers. High densification (relative density of 99.1%) and much desirable Vickers hardness (17.9 GPa) of Al2O3 parts were achieved at the sintering temperature of 1650 degrees C.
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| 19. |
- Bonander, Carl, 1988-
(författare)
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Searching for causal effects of road traffic safety interventions : applications of the interrupted time series design
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traffic-related injuries represent a global public health problem, and contribute largely to mortality and years lived with disability worldwide. Over the course of the last decades, improvements to road traffic safety and injury surveillance systems have resulted in a shift in focus from the prevention of motor vehicle accidents to the control of injury events involving vulnerable road users (VRUs), such as cyclists and moped riders. There have been calls for improvements to the evaluation of safety interventions due to methodological problems associated with the most commonly used study designs. The purpose of this licentiate thesis was to assess the strengths and limitations of the interrupted time series (ITS) design, which has gained some attention for its ability to provide valid effect estimates. Two national road safety interventions involving VRUs were selected as cases: the Swedish bicycle helmet law for children under the age 15, and the tightening of licensing rules for Class 1 mopeds. The empirical results suggest that both interventions were effective in improving the safety of VRUs. Unless other concurrent events affect the treatment population at the exact time of intervention, the effect estimates should be internally valid. One of the main limitations of the study design is the inability to identify why the interventions were successful, especially if they are complex and multifaceted. A lack of reliable exposure data can also pose a further threat to studies of interventions involving VRUs if the intervention can affect the exposure itself. It may also be difficult to generalize the exact effect estimates to other regions and populations. Future studies should consider the use of the ITS design to enhance the internal validity of before-after measurements.
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| 20. |
- Bonander, Carl, et al.
(författare)
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Synthetic Control Methods for the Evaluation of Single-Unit Interventions in Epidemiology: A Tutorial.
- 2021
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Ingår i: American journal of epidemiology. - : Oxford University Press (OUP). - 1476-6256 .- 0002-9262. ; 190:12, s. 2700-2711
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Tidskriftsartikel (refereegranskat)abstract
- Evaluating the impacts of population-level interventions (e.g., changes to state legislation) can be challenging as conducting randomized experiments is often impractical and inappropriate, especially in settings where the intervention is implemented in a single, aggregate unit (e.g., a country or state). A common nonrandomized alternative is to compare outcomes in the treated unit(s) with unexposed controls both before and after the intervention. However, the validity of these designs depends on the use of controls that closely resemble the treated unit on before-intervention characteristics and trends on the outcome, and suitable controls may be difficult to find because the number of potential control regions is typically limited. The synthetic control method provides a potential solution to these problems by using a data-driven algorithm to identify an optimal weighted control unit-a "synthetic control"-based on data from before the intervention from available control units. While popular in the social sciences, the method has not garnered as much attention in health research, perhaps due to a lack of accessible texts aimed at health researchers. We address this gap by providing a comprehensive, nontechnical tutorial on the synthetic control method, using a worked example evaluating Florida's "stand your ground" law to illustrate methodological and practical considerations.
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| 21. |
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| 22. |
- Moradi, Farnaz
(författare)
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Improving DRX Performance For Emerging Use Cases In 5G
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis proposes approaches and models to increase the energy saving of the User Equipment (UE) in Long-Term Evolution (LTE) and 5G. The focus is mainly on Discontinuous Reception (DRX), the UE energy saving mechanism that was first introduced in LTE and will play an important role in 5G too.In this thesis, we take two main approaches. The first approach is based on joint optimization of DRX and resource allocation in order to improve the energy saving (increase battery life time) for different scenarios. In particular, we propose utilizing the possibility of predicting the channel capacities for the UEs in order to jointly optimize the resource allocation and DRX parameters. We also propose two new flexible DRX approaches, DRXset and VDRX which are adjustable according to the traffic and channel information. The proposed solutions can create longer sleep opportunities for the UEs, as well as increased network capacity and flexibility.Aside from this, we investigate the performance of DRX in different use cases related to 5G. For example we study the impact of 5G Radio Access Network (RAN) slicing on the energy saving and sleep opportunity of the UEs. We propose slicing strategies that are less sensitive, in terms of UE energy usage, to the inter-slice resource sharing policies. We also propose a novel DRX state model for Device-to-Device (D2D) communication. The proposed state model is based on semi-Markov process similar to the legacy DRX. However, we introduce extra states and sub-states to the DRX state model in order to make it suitable for the D2D communication.
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| 23. |
- Obregon, Evanny, et al.
(författare)
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On the Feasibility of Indoor BroadbandSecondary Access to the 960-1215 MHz Aeronautical Spectrum
- 2013
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Ingår i: Transactions on Emerging Telecommunications Technologies. - : John Wiley & Sons. - 2161-3915. ; 24:7-8, s. 724-733
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we analyse the feasibility of indoor broadband service provisioning using secondary spectrum access to the 960–1215 MHz band, primarily allocated to the distance measuring equipment (DME) system for aeronautical navigation. We propose a practical secondary sharing scheme customised to the characteristics of the DME. Because the primary system performs a safety-of-life functionality, protection from harmful interference becomes extremely critical. The proposed scheme controls aggregate interference by imposing an individual interference threshold on the secondary users. We examine the feasibility of large scale secondary access in terms of the transmission probability of the secondary users that keeps the probability of harmful interference below a given limit. Uncertainties in the estimation of propagation loss and DME location affect the feasibility of the secondary access. Numerical results show that a large number of secondary users are able to operate in adjacent DME channels without harming the primary system even with limited accuracy on the estimation of the propagation loss.
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| 24. |
- Steer, Peter, et al.
(författare)
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The effect of a mixed meal on endothelium-dependent vasodilation is dependent on fat content in healthy humans
- 2003
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Ingår i: Clinical Science. - 0143-5221 .- 1470-8736. ; 105:1, s. 81-87
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Tidskriftsartikel (refereegranskat)abstract
- Impaired endothelium-dependent vasodilation (EDV) is an early marker of atherosclerosis. The aim of the present study was to investigate how meals with different fat contents influence endothelial vasodilatory function. A total of 26 young, healthy men and women aged 20-30 years ingested an ordinary Western meal [34 energy% (E%) fat, n =10], or isocaloric meals with low-fat (20 E%, n =8), or minimal-fat (3 E%, n =8) content. EDV was assessed as forearm blood flow (FBF) during local administration of 4 microg/min methacholine chloride (Mch-FBF) and endothelium-independent vasodilation as FBF during administration of 10 microg/min sodium nitroprusside (SNP-FBF) at baseline and 1 and 2 h after each meal. FBF was determined by venous occlusion plethysmography. An endothelial function index (EFI) was calculated as the Mch-FBF/SNP-FBF ratio. Both Mch-FBF and the EFI were decreased at 1 h after the 34 E% fat meal ( P <0.01 and P <0.05 respectively), but approached fasting levels after 2 h. Mch-FBF and EFI did not change significantly in the group consuming the 20 E% fat meal, but increased in the 3 E% fat group ( P <0.01 and P <0.05 compared with baseline for Mch-FBF and EFI respectively). SNP-FBF was not significantly affected by any of the meals. In conclusion, low-fat meals did not attenuate EDV, in contrast with an ordinary Western meal, which transiently impaired EDV. Our findings indicate that a dietary fat content of 20 E% or less might be beneficial to endothelial vasodilatory function.
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| 25. |
- Taddia, Francesco, et al.
(författare)
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Analysis of broad-lined Type Ic supernovae from the (intermediate) Palomar Transient Factory
- 2019
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 621
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Tidskriftsartikel (refereegranskat)abstract
- We study 34 Type Ic supernovae that have broad spectral features (SNe Ic-BL). This is the only SN type found in association with long-duration gamma-ray bursts (GRBs). We obtained our photometric data with the Palomar Transient Factory (PTF) and its continuation, the intermediate PTF (iPTF). This is the first large, homogeneous sample of SNe Ic-BL from an untargeted survey. Furthermore, given the high observational cadence of iPTF, most of these SNe Ic-BL were discovered soon after explosion. We present K-corrected Bgriz light curves of these SNe, obtained through photometry on template-subtracted images. We analyzed the shape of the r-band light curves, finding a correlation between the decline parameter Delta m(15) and the rise parameter Delta m-(10 ). We studied the SN colors and, based on g - r, we estimated the host-galaxy extinction for each event. Peak r-band absolute magnitudes have an average of -18.6 +/- 0.5 mag. We fit each r-band light curve with that of SN 1998bw (scaled and stretched) to derive the explosion epochs. We computed the bolometric light curves using bolometric corrections, r-band data, and g - r colors. Expansion velocities from Fen were obtained by fitting spectral templates of SNe Ic. Bolometric light curves and velocities at peak were fitted using the semianalytic Arnett model to estimate ejecta mass M-ej , explosion energy E-K and Ni-56 mass M( Ni-56) for each SN. We find average values of M-ej = 4 +/- 3 M-circle dot, E-K = (7 +/- 6) x 10(51) erg, and M( Ni-56) = 0.31 +/- 0.16 M-circle dot . The parameter distributions were compared to those presented in the literature and are overall in agreement with them. We also estimated the degree of Ni-56 mixing using scaling relations derived from hydrodynamical models and we find that all the SNe are strongly mixed. The derived explosion parameters imply that at least 21% of the progenitors of SNe Ic-BL are compatible with massive (>28 M-circle dot), possibly single stars, whereas at least 64% might come from less massive stars in close binary systems.
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