| 1. |
- Ahlström, Torbjörn, et al.
(författare)
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Genom livet i den långsamma filen
- 2005
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Ingår i: Arkeologi och naturvetenskap : Gyllenstiernska Krapperupstiftelsens Symposium Nr 6 År 2003 - Gyllenstiernska Krapperupstiftelsens Symposium Nr 6 År 2003. - 1100-7095. - 9187944146 ; 6, s. 215-234
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Almqvist, Torbjörn, et al.
(författare)
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Thermal transient rough EHL line contact simulations by aid of computational fluid dynamics
- 2008
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 41:8, s. 683-693
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Tidskriftsartikel (refereegranskat)abstract
- Reynolds equation is the pre-dominantly used PDE for modelling the fluid flow or more accurately the fluid pressure in an elastohydrodynamic lubrication (EHL) contact. The equation is derived by combining the two conservation equations of momentum and continuity into a single equation for the fluid pressure. The numerical approach for theoretical investigations performed on EHL contacts in this work is somewhat different. The modelling of the fluid flow is based on a computational fluid dynamic (CFD) technique. The fluid flow is simulated by aid of the equations of momentum and continuity in a more complete form and when the thermodynamics is incorporated, the equation of energy. The aim of the investigation was to examine whether the CFD technique could be used to handle thermal transient rough EHL line contacts. It is shown that commercial CFD software can be modified to meet such requirements. The influence of thermal effects on the flow under sliding motion was investigated. The non-Newtonian model used in this work is the Ree-Eyring model. It is shown that the choice of the Eyring stress in the model influences flow in the contacts. If the thermal properties of the surrounding solids differ, it has been shown experimentally and theoretically that a dimple or increased central film thickness may appear in the EHL contacts. This work shows that the governing mechanisms that result in the dimple are also present in thermal transient rough EHL line contacts.
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| 3. |
- Andersson, Per-Åke, 1945-
(författare)
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Multi-year maintenance optimisation for paved public roads - segment based modelling and price-directive decomposition
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I avhandlingen studeras hur kostnadseffektiva underhålls- (uh-)planer för belagd väg kan genereras, på basis av information om aktuellt vägytetillstånd och funktionella modeller för kostnads- och tillståndsförändringar, delvis utvecklade i samarbete med svenska Vägverket (VV). Tilltänkt användning är på strategisk och programnivå, innan mer detaljerad objektinformation finns att tillgå. Till skillnad från hittills använda modeller, så genereras individuella uh-planer för varje vägsegment (en homogen vägsträcka vad gäller aktuellt beläggningstillstånd och beläggningshistorik), i kontinuerliga tillstånds- och åtgärdsrum. Genom användning av Lagrangerelaxerande optimeringsteknik, så kan de speciella nytto/kostnads-kvot-villkor som VV ålägger varje uh-objekt naturligen hanteras med dualpriser för budgetvillkoren. Antalet vägsegment som konkurrerar om budgetmedlen är vanligtvis stort. Data från VV:s Vägdatabank för Värmland har använts, omfattande ca 9000 vägsegment. Genom den stora datamängden har datorprogrammen implementerats för parallellbearbetning. Under avhandlingsarbetet har projektet beviljats tillgång till Monolith PCklustret vid NSC. För att kunna reducera optimeringskörtiderna har modell- och metodutveckling varit nödvändig. Genom att aggregera vägsegmenten till vägklasser har goda startvärden på dualpriserna erhållits. Genom utvecklingen av en speciell restvärdesrutin har den explicit behandlade tidsperioden kunnat reduceras. Vid lösandet av det duala subproblemet har speciell uppmärksamhet ägnats åt de diskretiseringseffekter som uppstår i metoden dynamisk programmering. En typ av tillämpning avser ett delvägnät, exempelvis en väg. Valideringsstudier har genomförts på väg 63 i Värmland – med lovande men inte tillfredsställande resultat (se nedan). En speciell modell för samordnat uh beaktar stordriftsfördelarna vid samtidig åtgärd på en hel vägsträcka. Den andra huvudtypen av studier gäller ett helt nätverk. Flera metodtyper har tillämpats, både för att lösa de relaxerade optimeringsproblemen och för att generera uhplaner som uppfyller budgetvillkoren. För en anständig diskretisering är körtiderna för hela Värmland mindre än 80 CPU-timmar. Genom en a posteriori primal heuristik reduceras kraven på parallellbearbetning till ett litet PC-kluster. Avhandlingen studerar vidare effekterna av omfördelade budgetmedel samt en övergång till en transparent, stokastisk modell – vilka båda visar små avvikelser från basmodellen.Optimeringsresultaten för Värmland indikerar att budgetnivåer på ca 40% av Värmlands verkliga uh-budget är tillräckliga. Dock saknas viktiga kostnadsdrivande faktorer i denna första modellomgång, exempelvis vissa funktionella prestanda (säkerhet), all miljöpåverkande prestanda (buller etc.) och strukturell prestanda (ex.vis bärighet, som enbart modelleras via ett åldersmått). För ökad tilltro till PMS i allmänhet och optimering i synnerhet, bör avvikelserna analyseras ytterligare och leda till förbättringar vad gäller tillståndsmätning, tillståndseffekt- & kostnadsmodellering samt matematisk modellering & implementering.
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| 4. |
- Andersson-Sköld, Yvonne, 1957-, et al.
(författare)
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Coal tar-containing asphalt : Resource or hazardous waste?
- 2007
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Ingår i: Journal of Industrial Ecology. - : Wiley-Blackwell. - 1088-1980 .- 1530-9290. ; 11:4, s. 99-116
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Tidskriftsartikel (refereegranskat)abstract
- Coal tar was used in Sweden for the production of asphalt and for the drenching of stabilization gravel until 1973. The tar has high concentrations of polycyclic aromatic hydrocarbons (PAH), some of which may be strongly carcinogenic. Approximately 20 million tonnes of tar-containing asphalt is present in the public roads in Sweden. Used asphalt from rebuilding can be classified as hazardous waste according to the Swedish Waste Act. The cost of treating the material removed as hazardous waste can be very high due to the large amount that has to be treated, and the total environmental benefit is unclear. The transport of used asphalt to landfill or combustion will affect other environmental targets. The present project, based on three case studies of road projects in Sweden, evaluates the consequences of four scenarios for handling the material: reuse, landfill, biological treatment, and incineration. The results show that reuse of the coal tar-containing materials in new road construction is the most favorable alternative in terms of cost, material use, land use, energy consumption, and air emissions.
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| 5. |
- Axelsson, Maria, 1976-
(författare)
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Ifrågasatta företagare : Konkursförvaltares syn på kvinnor och män som företagsgäldenärer under 1900-talet
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The principle purpose of this thesis has been to study and analyse the conception of men and women in business bankruptcy during the 20th century. The analysis is built on a theoretical gender perspective and, combining this view and business and bankruptcy research, the thesis has focused on five themes: business networks, bank contacts, business competence, business characteristics and finally bankruptcy causes. These themes have been in focus when analysing bankruptcies in Uppsala 1920-1939, 1988, 1992 and 1996. A questionnair- and interview study with receivers active in Sweden 2001 has also been carried out. From the bankruptcy cases that have been studied, no specific gender differences have really been discovered. There were some variations between men and women, but it is very hard to claim that these are related to the sex of the debtor more than to the branch or to the individuals. Changes from the inter-war period to the latter part of the 20th century are in these respects also small. The image that the receivers gave through the questionnaire and interview study indicates on the other hand that there existed a conception that men and women seemed different as business owners. It is obvious that there were many receivers who thought that women were different from men in a situation of business bankruptcy, even though several of them stated that they did not beleive in any gender differences.
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| 6. |
- Bäck, Henry, 1947, et al.
(författare)
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Den svenska politiken : Struktur, processer och resultat
- 2006
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- I Den svenska politiken ges en bred översikt över statsskicket och politiken. Med utgångspunkt i stats- och samhällsvetenskaplig forskning beskrivs och analyseras staten, EU, kommuner och landsting. Det politiska systemet gör det möjligt att fatta gemensamma beslut och skrida till gemensam handling i samhället. Till skillnad från andra system för gemensamt handlande verkar politiken genom att använda makt. För att kunna fånga maktutövningen i ett politiskt system krävs analytiska instrument i form av samhällsvetenskaplig teori. I boken behandlas särskilt det politiska systemets inbyggda kontrollmekanismer och den politiska processen. Formandet av den offentliga politiken illustreras med några centrala politikområden i den moderna svenska politiken. Här beskrivs och analyseras både det formella normativa ramverket och ”hur det verkligen går till”. För att begripa dagens svenska politik behöver vi kunna göra jämförelser i både tid och rum, och därför anläggs ett historiskt perspektiv och görs utblickar på andra länder.
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| 7. |
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| 8. |
- Cabric, Sanja, et al.
(författare)
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Islet Surface Heparinization Prevents the Instant-Blood Mediated Inflammatory Reaction in Islet Transplantation
- 2007
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 56:8, s. 2008-2015
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE—In clinical islet transplantation, the instant blood-mediated inflammatory reaction (IBMIR) is a major factor contributing to the poor initial engraftment of the islets. This reaction is triggered by tissue factor and monocyte chemoattractant protein (MCP)-1, expressed by the transplanted pancreatic islets when the islets come in contact with blood in the portal vein. All currently identified systemic inhibitors of the IBMIR are associated with a significantly increased risk of bleeding or other side effects. To avoid systemic treatment, the aim of the present study was to render the islet graft blood biocompatible by applying a continuous heparin coating to the islet surface.RESEARCH DESIGN AND METHODS—A biotin/avidin technique was used to conjugate preformed heparin complexes to the surface of pancreatic islets. This endothelial-like coating was achieved by conjugating barely 40 IU heparin per full-size clinical islet transplant.RESULTS—Both in an in vitro loop model and in an allogeneic porcine model of clinical islet transplantation, this heparin coating provided protection against the IBMIR. Culturing heparinized islets for 24 h did not affect insulin release after glucose challenge, and heparin-coated islets cured diabetic mice in a manner similar to untreated islets.CONCLUSIONS—This novel pretreatment procedure prevents intraportal thrombosis and efficiently inhibits the IBMIR without increasing the bleeding risk and, unlike other pretreatment procedures (e.g., gene therapy), without inducing acute or chronic toxicity in the islets.
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| 9. |
- Daneva (Mitradjieva), Maria, et al.
(författare)
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A Sequential Linear Programming Algorithm with Multi-dimensional Search : Derivation and Convergence
- 2007
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We present a sequential linear programming, SLP, algorithm in which the traditional line-search step is replaced by a multi-dimensional search. The algorithm is based on inner approximations of both the primal and dual spaces, which yields a method which in the primal space combines column and constraint generation. The algorithm does not use a merit function, and the linear programming subproblem of the algorithm differs from the one obtained in traditional methods of this type, in the respect that linearized constraints are taken into account only implicitly in a Lagrangiandual fashion. Convergence to a point that satisfies the Karush-Kuhn-Tucker conditions is established. We apply the new method to a selection of the Hoch-Schittkowski’s nonlinear test problems and report a preliminary computational study in a Matlab environment. Since the proposed algorithmcombines column and constraint generation, it should be advantageous with large numbers of variables and constraints.
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| 10. |
- Eriksson, Mathilda, et al.
(författare)
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Utilization of a right-handed coiled-coil protein from archaebacterium Staphylothermus marinus as a carrier for cisplatin
- 2009
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Ingår i: Anticancer Research. - 0250-7005 .- 1791-7530. ; 29:1, s. 11-18
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The nano-sized right-handed coiled-coil (RHCC) protein, originating from the archaebacterium Staphylothermus marinus, is stable at high salt concentrations, high temperatures, high pressures and extremes of pH. Its crystal structure reveals four hydrophobic cavities which can incorporate heavy metals. Nano-sized compounds have been used to carry cytotoxic drugs to tumours, avoiding delivery to healthy tissue, in part due to enhanced permeability in tumour blood vessels (enhanced permeability and retention effect). MATERIALS AND METHODS: The ability of RHCC to carry the platinum-containing chemotherapeutic drug cisplatin to cells, while retaining the cytotoxic potential was tested both in vitro and in vivo. RESULTS: RHCC was able to bind and enter cells in vitro and was not severely toxic or immunogenic in mice. Moreover, RHCC incorporated cisplatin, without inhibiting the cytotoxic potential of the drug against tumour cell lines in vitro or in vivo. CONCLUSION: RHCC can be used as a carrier of cisplatin without abrogating the effect of the drug.
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| 11. |
- Eriksson, Therese, et al.
(författare)
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Magnetic short-range order in the new ternary phase Mn8Pd15Si7
- 2005
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 403:1-2, s. 19-28
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Tidskriftsartikel (refereegranskat)abstract
- A new compound, Mn8Pd15Si7, is reported to crystallize in a face centered cubic unit cell of dimension a = 12.0141(2) Å, space group, and can thus be classified as a G-phase. The crystal structure was studied by single crystal X-ray diffraction, X-ray and neutron powder diffraction and electron diffraction. A filled Mg6Cu16Si7 type structure was found, corresponding to the Sc11Ir4 type structure. The magnetic properties were investigated by magnetization measurements and Reverse Monte Carlo modeling of low temperature magnetic short-range order (SRO). Dominating near neighbor antiferromagnetic correlations were found between the Mn atoms and geometric frustration in combination with random magnetic interactions via metal sites with partial Mn occupancy were suggested to hinder formation of long-range magnetic order.
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| 12. |
- Falkmer, Torbjörn, et al.
(författare)
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Fixation identification in centroid versus start-point modes using eye-tracking data
- 2008
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Ingår i: Perceptual and Motor Skills. - : Sage Publications. - 0031-5125 .- 1558-688X. ; 106:3, s. 710-724
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Tidskriftsartikel (refereegranskat)abstract
- Fixation-identification algorithms, needed for analyses of eye movements, may typically be separated into three categories, viz. (i) velocity-based algorithms, (ii) area-based algorithms, and (iii) dispersion-based algorithms. Dispersion-based algorithms are commonly used but this application introduces some difficulties, one being optimization. Basically, there are two modes to reach this goal of optimization, viz., the start-point mode and the centroid mode. The aim of the present study was to compare and evaluate these two dispersion-based algorithms. Manual inspections were made of 1,400 fixations in each mode. Odds ratios showed that by using the centroid mode for fixation detection, a valid fixation is 2.86 times more likely to be identified than by using the start-point mode. Moreover, the algorithm based on centroid mode dispersion showed a good interpretation speed, accuracy, robustness, and ease of implementation, as well as adequate parameter settings.
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| 13. |
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| 14. |
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| 15. |
- Forkby, Torbjörn, 1965, et al.
(författare)
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Serviceinsatser inom socialtjänsten.
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Inom den sociala barn- och ungdomsvården utvecklas mer av förebyggande insatser i form av så kallade serviceinsatser. Rapporten är en studie i ett tjugotal kommuner av hur inriktning ser ut, och särskilt hur barns rättsäkerhet och skydd hanteras.
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| 16. |
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| 17. |
- Forseth, Torbjörn, et al.
(författare)
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Thermal growth performance of juvenile brown trout Salmo trutta : no support for thermal adaptation hypotheses
- 2009
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 74:1, s. 133-149
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Tidskriftsartikel (refereegranskat)abstract
- Using thermal growth data from eight populations of anadromous and lake-feeding brown trout Salmo trutta, hypotheses of adaptation to local optima and countergradient variation in growth were tested. The adaptation to local optima hypothesis suggests that natural selection can shift optimal performance temperatures to match the prevailing temperature in a new or changed thermal niche. In contradiction, the countergradient variation hypothesis suggests that populations from hostile environments perform better than conspecifics from benign environments at all temperatures. In this study, growth capacity varied between populations but there was no significant correlation between any of the estimated thermal performance parameters (e.g. lower and upper thermal growth limits, optimal temperature for growth and maximum growth capacity) and natural climatic conditions among populations. Hence, S. trutta growth response to temperature lends no support for either of the two suggested thermal adaptation hypotheses. Instead, growth capacity among populations tended to correlate positively with female size at maturity.
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| 18. |
- Hansson, Maria, et al.
(författare)
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Polychlorinated biphenyl load, aryl hydrocarbon receptor, and cytochrome P4501A1 induction in a wild population of Atlantic salmon (Salmo salar) from the Baltic Sea
- 2006
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268. ; 25:8, s. 2197-2207
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Tidskriftsartikel (refereegranskat)abstract
- The toxicity induced by several environmental pollutants is mediated by the aryl hydrocarbon receptor (AHR), which controls the expression of many biotransformation genes, such as cytochrome P4501A1 (CYP1A1). Previous studies have indicated that fish populations can evolve tolerance to persistent chlorinated pollutants by down-regulating the AHR pathway. Here, we measure to what extent tissue loads of polychlorinated biphenyl (PCB) congeners and AHR genotypes contribute to biotransformation capacity in wild, foraging Atlantic salmon (Salmo salar L.) from the Baltic Sea. In muscle, the sum of the 21 most common PCB congeners (ΣPCB) was correlated with three extracted AHR agonists (PCBs 77/110, 118/123/149, and 105/132/153). Both the AHR agonists as well as ΣPCB were correlated with lipid content. The ΣPCB, controlled for the effects of sex and lipid content in muscle tissue, did not predict mRNA transcript levels of the measured AHRs (AHR2α, AHR2γ, and AHR2δ) or CYP1A1 in liver. However, all AHR2 mRNA transcript levels were positively correlated with CYP1A1 level. In turn, the CYP1A1 level was negatively correlated with concentration of the muscle-tissue antioxidant astaxanthin, suggesting that astaxanthin is depleted when biotransformation processes (CYP1A1) are activated. No correlation was found between ethoxyresorufin-O-deethylase activity and ΣPCB, CYP1A1, or antioxidant levels. In 5′-flanking regions of the AHR2 genes, we identified multiple allelic variants that were used for genotyping. The mRNA transcript level of AHR2α was significantly associated with the AHR2α 5′-flanking region genotype and with the interaction of the genotype and individual PCB level. These results suggest that in wild Atlantic salmon from the Baltic Sea, active production of AHR2 mRNA by means of PCB exposure may be affected by genetic polymorphisms at the AHR2 loci.
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| 19. |
- Hansson, Maria, et al.
(författare)
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Polychlorinated biphenyl (PCB) load, lipid reserves and biotransformation activity in migrating Atlantic salmon from River Mörrum, Sweden.
- 2009
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 157:12, s. 3396-3403
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Tidskriftsartikel (refereegranskat)abstract
- Atlantic salmon accumulate high levels of contaminants such as polychlorinated biphenyls (PCBs) in their lipids during the adult growth phase spent at sea. The lipids are later utilized during migration for swimming and biological adaptations. We hypothesize that migrating salmons' biotransformation processes are affected by the high levels of built-up PCBs compared to salmon that in a pre-migrational stage. For these analyses we sampled adult Atlantic salmon during migration in the Swedish River Mörrum and measured the 21 most common PCB congeners ( summation operatorPCB) and lipid levels in muscle tissue, aryl hydrocarbon receptor (AHR2) and cytochrome P4501A1 (CYP1A1) transcript levels as well as ethoxyresorufin-O-deethylase activity (EROD) in liver. We also determined which AHR2 genotypes the salmon carried. We show that EROD activity is correlated to CYP1A1 level but not to summation operatorPCB concentration. summation operatorPCB concentration does not predict levels of neither the AHR2 nor CYP1A1 genes. We find no associations between specific AHR2 transcription levels and AHR2 genotypes or a correlation between AHR2 and CYP1A1 transcription levels, which is in direct contrast to pre-migrational adult salmon from the Baltic Sea. When we compare River Mörrum to salmon we have previously sampled in the Baltic Sea we show that migrating salmon have significantly lower lipid levels in their muscles; higher muscle concentrations of summation operatorPCB on a lipid basis; and significantly lower CYP1A1 and EROD levels compared to salmon from the Baltic Sea. Also, transcript levels of three out of four AHR2 genes are significantly different. In conclusion, migrating Swedish Atlantic salmon carry higher concentrations of PCBs in their lipids compared to salmon in the Baltic Sea, but have lower activation of biotransformation genes and enzymes. Our results indicate that accumulated pollutants from the Baltic Sea are deactivated inside the migrating salmon's lipid tissues and increase in concentration when migration is initiated thereby limiting their impact on biotransformation processes.
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| 20. |
- Kammerlind, Ann-Sofi, 1969-, et al.
(författare)
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Reliability of clinical balance tests and subjective ratings in dizziness and disequilibrium
- 2005
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Ingår i: Advances in Physiotherapy. - : Informa UK Limited. - 1403-8196 .- 1651-1948. ; 7:3, s. 96-107
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to assess (i) the test–retest and inter-rater reliability of, and (ii) the relationships between, commonly used clinical balance tests and subjective ratings in subjects with dizziness and disequilibrium. Fifty subjects (26 men and 24 women, mean age 63 years) with dizziness and disequilibrium following acute unilateral vestibular loss or central neurological dysfunction were tested with static and dynamic clinical balance tests, visual analogue scales (VAS), University of California Los Angeles Dizziness Questionnaire (UCLA-DQ), Dizziness Beliefs Scale (DBS), European Quality of Life questionnaire (EQ-5D), Dizziness Handicap Inventory (DHI), and Hospital Anxiety and Depression Scale (HADS). Most tests showed good test–retest and inter-rater reliability. Few correlations were seen between objective and subjective tests, but several correlations were found between the different subjective instruments. Sharpened Romberg's test eyes closed, standing on foam eyes closed, standing on one leg eyes open and walking in a figure-of-eight are recommended as reliable and appropriate clinical balance tests in subjects with dizziness and disequilibrium. Subjects with central lesions may have difficulties when rating their symptoms on VAS. Total scores rather than scores for separate items are recommended for UCLA-DQ and DHI.
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| 21. |
- Kiwiel, Krzysztof C., et al.
(författare)
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Lagrangian relaxation via ballstep subgradient methods
- 2007
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Ingår i: Mathematics of Operations Research. - : Institute for Operations Research and the Management Sciences (INFORMS). - 0364-765X .- 1526-5471. ; 32:3, s. 669-686
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Tidskriftsartikel (refereegranskat)abstract
- We exhibit useful properties of ballstep subgradient methods for convex optimization using level controls for estimating the optimal value. Augmented with simple averaging schemes, they asymptotically find objective and constraint subgradients involved in optimality conditions. When applied to Lagrangian relaxation of convex programs, they find both primal and dual solutions, and have practicable stopping criteria. Up until now, similar results have only been known for proximal bundle methods, and for subgradient methods with divergent series stepsizes, whose convergence can be slow. Encouraging numerical results are presented for large-scale nonlinear multicommodity network flow problems. ©2007 INFORMS.
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| 22. |
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| 23. |
- Larsson, Anders, et al.
(författare)
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Circadian variability of cystatin C, creatinine, and glomerular filtration rate (GFR) in healthy men during normal sleep and after an acute shift of sleep.
- 2008
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Ingår i: Chronobiol Int. - : Informa UK Limited. - 1525-6073 .- 0742-0528. ; 25:6, s. 1047-61
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Tidskriftsartikel (refereegranskat)abstract
- Circadian variability of cystatin C, creatinine, and glomerular filtration rate (GFR) in healthy men during normal sleep and after an acute shift of sleep.Larsson A, Akerstedt T, Hansson LO, Axelsson J.Section of Clinical Chemistry, Department of Medical Sciences, Uppsala University, Uppsala, Sweden. anders.larsson@akademiska.seThe estimation of the glomerular filtration rate (GFR) is essential for the evaluation of patients with kidney disease and for the treatment of patients with medications that are eliminated by the kidneys. Plasma cystatin C has been shown in several studies to be superior to plasma creatinine for the estimation of GFR. However, there is limited information on the circadian variation of cystatin C and estimated GFR using cystatin C (eGFR(CystC)) or "The Modification of Diet in Renal Disease Study" (MDRD) (eGFR(MDRD)) equations. We studied the circadian variation of cystatin C and creatinine during night- and day-sleep conditions in seven healthy volunteers. Serum samples were collected every hour (48 samples per individual) to evaluate the effect of different sampling times on the test results. The median intra-individual coefficients of variations for the studied markers were 4.2% for creatinine, 4.7% for eGFR(MDRD), 5.5% for cystatin C, and 7.7% for eGFR(CystC). Neither cystatin C nor creatinine differed significantly between the night- and day-sleep conditions. Cystatin C differed significantly with time of day (p=.0003), but this was not the case for creatinine (p=.11). The circadian variation of cystatin C was minor. Small but significant increases in creatinine values and a decrease of eGFR(MDRD) were observed after food intake. Thus, cystatin C and creatinine sampling does not have to be restricted to specific times of the day.
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| 24. |
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| 25. |
- Larsson, Helena, et al.
(författare)
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A Swedish survey of occupational therapists' involvement and performance in driving assessments
- 2007
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Ingår i: Scandinavian Journal of Occupational Therapy. - : Informa UK Limited. - 1103-8128 .- 1651-2014. ; 14:4, s. 215-220
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to examine the extent to which occupational therapists (OTs) are involved in driving assessments in Sweden and how these assessments are performed. A questionnaire was sent to 154 geriatric, rehabilitation, and neurological clinics, and additionally directly to 19 OTs who had purchased a test battery specifically used for driving assessments. The response rate was 60%. Of those responding, 57% reported being involved in fitness-to-drive assessments. However, such assessments were carried out in various manners and diverse methods were used, ranging from unstandardized activity assessments to a test developed specifically for driving assessments. Only 19% used on-road driving tests as a complement to the clinical assessments. Apart from the lack of appropriate methods, the respondents said that they did not have sufficient knowledge to perform driving assessments and expressed a need for further education. In the future it seems necessary for OTs in Sweden to undergo specialized training and perform the assessments on a regular basis to maintain a high level of competence as driving assessors.
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| 26. |
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| 27. |
- Larsson, Michael, 1970-
(författare)
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Natural products from nonracemie building blocks : synthesis of pine sawfly pheromones
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. Hence, the sexual pheromone of Microdiprion pallipes, a propanoate ester of one or several isomers of 3,7,11-trimethyltridecan-2-ol, was synthesised, both as a mixture of all isomers and as the sixteen pure, individual stereoisomers. These compounds were obtained by joining different enantiopure building blocks stemming from the chiral pool. When compared with some synthetic blends, both the propanoate esters of the stereoisomeric erythro-3,7,11-trimethyltridecan-2-ols originally found in the extract from the female of M. pallipes, surprisingly, showed lower activities in biological studies. Indeed, the propanoates of two threo-isomers gave significantly higher responses in biological tests, than did the propanoates of the two natural erythro-ones. Because the synthetic strategy used earlier was not very efficient for the preparation of the threo-isomers of 3,7,11-trimethyltridecan-2-ol, we were encouraged to look for alternative synthetic approaches. The new synthetic strategy chosen led us to two key synthetic building blocks, an O-protected derivative of (2S,3S)-3-methyl-4-(phenylsulfonyl)butan-2-ol butanol and (3R,7R)-1-iodo-3,7-dimethylnonane. Deprotonation of the former followed by alkylation with the latter should give a compound with the desired carbon skeleton. For efficient preparation of the first building block, we developed a new diastereoselective addition reaction of dialkylzincs to some chiral aldehydes, the products of which were diastereomerically enriched 1,2-dialkyl-alkanols. Using this method, each enantiomer of the desired building block was obtained via efficient diastereoselective addition of dimethylzinc to each enantiomer of a 2-methylaldehyde. The resulting product, a diastereomerically and enantiomerically highly enriched 3-methyl-2-alkanol was further purified by enzyme catalysed acylation followed by some functional group interconversions. The second building block was prepared via convergent multistep synthesis, starting from a single, enantiomerically pure compound, (R)-2-methylsuccinic acid 4-t-butyl ester, derived from the chiral pool. The two enantiomerically pure building blocks, so obtained, were coupled together. Some additional functional group manipulations of the product produced furnished the desired isomer, which had shown the highest activity in field tests of the M. pallipes, namely the propanoate ester of (2S,3R,7R,11R)-3,7,11-trimethyltridecan-2-ol. This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. Hence, the sexual pheromone of Microdiprion pallipes, a propanoate ester of one or several isomers of 3,7,11-trimethyltridecan-2-ol, was synthesised, both as a mixture of all isomers and as the sixteen pure, individual stereoisomers. These compounds were obtained by joining different enantiopure building blocks stemming from the chiral pool. When compared with some synthetic blends, both the propanoate esters of the stereoisomeric erythro-3,7,11-trimethyltridecan-2-ols originally found in the extract from the female of M. pallipes, surprisingly, showed lower activities in biological studies. Indeed, the propanoates of two threo-isomers gave significantly higher responses in biological tests, than did the propanoates of the two natural erythro-ones. Because the synthetic strategy used earlier was not very efficient for the preparation of the threo-isomers of 3,7,11-trimethyltridecan-2-ol, we were encouraged to look for alternative synthetic approaches. The new synthetic strategy chosen led us to two key synthetic building blocks, an O-protected derivative of (2S,3S)-3-methyl-4-(phenylsulfonyl)butan-2-ol butanol and (3R,7R)-1-iodo-3,7-dimethylnonane. Deprotonation of the former followed by alkylation with the latter should give a compound with the desired carbon skeleton. For efficient preparation of the first building block, we developed a new diastereoselective addition reaction of dialkylzincs to some chiral aldehydes, the products of which were diastereomerically enriched 1,2-dialkyl-alkanols. Using this method, each enantiomer of the desired building block was obtained via efficient diastereoselective addition of dimethylzinc to each enantiomer of a 2-methylaldehyde. The resulting product, a diastereomerically and enantiomerically highly enriched 3-methyl-2-alkanol was further purified by enzyme catalysed acylation followed by some functional group interconversions. The second building block was prepared via convergent multistep synthesis, starting from a single, enantiomerically pure compound, (R)-2-methylsuccinic acid 4-t-butyl ester, derived from the chiral pool. The two enantiomerically pure building blocks, so obtained, were coupled together. Some additional functional group manipulations of the product produced furnished the desired isomer, which had shown the highest activity in field tests of the M. pallipes, namely the propanoate ester of (2S,3R,7R,11R)-3,7,11-trimethyltridecan-2-ol. This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. Hence, the sexual pheromone of Microdiprion pallipes, a propanoate ester of one or several isomers of 3,7,11-trimethyltridecan-2-ol, was synthesised, both as a mixture of all isomers and as the sixteen pure, individual stereoisomers. These compounds were obtained by joining different enantiopure building blocks stemming from the chiral pool. When compared with some synthetic blends, both the propanoate esters of the stereoisomeric erythro-3,7,11-trimethyltridecan-2-ols originally found in the extract from the female of M. pallipes, surprisingly, showed lower activities in biological studies. Indeed, the propanoates of two threo-isomers gave significantly higher responses in biological tests, than did the propanoates of the two natural erythro-ones. Because the synthetic strategy used earlier was not very efficient for the preparation of the threo-isomers of 3,7,11-trimethyltridecan-2-ol, we were encouraged to look for alternative synthetic approaches. The new synthetic strategy chosen led us to two key synthetic building blocks, an O-protected derivative of (2S,3S)-3-methyl-4-(phenylsulfonyl)butan-2-ol butanol and (3R,7R)-1-iodo-3,7-dimethylnonane. Deprotonation of the former followed by alkylation with the latter should give a compound with the desired carbon skeleton. For efficient preparation of the first building block, we developed a new diastereoselective addition reaction of dialkylzincs to some chiral aldehydes, the products of which were diastereomerically enriched 1,2-dialkyl-alkanols. Using this method, each enantiomer of the desired building block was obtained via efficient diastereoselective addition of dimethylzinc to each enantiomer of a 2-methylaldehyde. The resulting product, a diastereomerically and enantiomerically highly enriched 3-methyl-2-alkanol was further purified by enzyme catalysed acylation followed by some functional group interconversions. The second building block was prepared via convergent multistep synthesis, starting from a single, enantiomerically pure compound, (R)-2-methylsuccinic acid 4-t-butyl ester, derived from the chiral pool. The two enantiomerically pure building blocks, so obtained, were coupled together. Some additional functional group manipulations of the product produced furnished the desired isomer, which had shown the highest activity in field tests of the M. pallipes, namely the propanoate ester of (2S,3R,7R,11R)-3,7,11-trimethyltridecan-2-ol.
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| 28. |
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| 29. |
- Larsson, Torbjörn, et al.
(författare)
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Convergent Lagrangian heuristics for nonlinear minimum cost network flows
- 2008
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Ingår i: European Journal of Operational Research. - : Elsevier BV. - 0377-2217 .- 1872-6860. ; 189:2, s. 324-346
-
Tidskriftsartikel (refereegranskat)abstract
- We consider the separable nonlinear and strictly convex single-commodity network flow problem (SSCNFP). We develop a computational scheme for generating a primal feasible solution from any Lagrangian dual vector, this is referred to as "early primal recovery". It is motivated by the desire to obtain a primal feasible vector before convergence of a Lagrangian scheme, such a vector is not available from a Lagrangian dual vector unless it is optimal. The scheme is constructed such that if we apply it from a sequence of Lagrangian dual vectors that converge to an optimal one, then the resulting primal (feasible) vectors converge to the unique optimal primal flow vector. It is therefore also a convergent Lagrangian heuristic, akin to those primarily devised within the field of combinatorial optimization but with the contrasting and striking advantage that it is guaranteed to yield a primal optimal solution in the limit. Thereby we also gain access to a new stopping criterion for any Lagrangian dual algorithm for the problem, which is of interest in particular if the SSCNFP arises as a subproblem in a more complex model. We construct instances of convergent Lagrangian heuristics that are based on graph searches within the residual graph, and therefore are efficiently implementable, in particular we consider two shortest path based heuristics that are based on the optimality conditions of the original problem. Numerical experiments report on the relative efficiency and accuracy of the various schemes. © 2007 Elsevier B.V. All rights reserved.
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| 30. |
- Larsson, Torbjörn, 1957-, et al.
(författare)
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Global optimality conditions for discrete and nonconvex optimization-with applications to Lagrangian heuristics and column generation
- 2006
-
Ingår i: Operations Research. - : Institute for Operations Research and the Management Sciences (INFORMS). - 0030-364X .- 1526-5463. ; 54:3, s. 436-453
-
Tidskriftsartikel (refereegranskat)abstract
- The well-known and established global optimality conditions based on the Lagrangian formulation of an optimization problem are consistent if and only if the duality gap is zero. We develop a set of global optimality conditions that are structurally similar but are consistent for any size of the duality gap. This system characterizes a primal-dual optimal solution by means of primal and dual feasibility, primal Lagrangian ε-optimality, and, in the presence of inequality constraints, a relaxed complementarity condition analogously called δ-complementarity. The total size ε + δ of those two perturbations equals the size of the duality gap at an optimal solution. Further, the characterization is equivalent to a near-saddle point condition which generalizes the classic saddle point characterization of a primal-dual optimal solution in convex programming. The system developed can be used to explain, to a large degree, when and why Lagrangian heuristics for discrete optimization are successful in reaching near-optimal solutions. Further, experiments on a set-covering problem illustrate how the new optimality conditions can be utilized as a foundation for the construction of new Lagrangian heuristics. Finally, we outline possible uses of the optimality conditions in column generation algorithms and in the construction of core problems. © 2006 INFORMS.
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| 31. |
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| 32. |
- Lundberg, Emma, et al.
(författare)
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Site-specifically conjugated anti-HER2 Affibody® molecules as one-step reagents for target expression analyses on cells and xenograft samples
- 2007
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Ingår i: JIM - Journal of Immunological Methods. - : Elsevier BV. - 0022-1759 .- 1872-7905. ; 319:1-2, s. 53-63
-
Tidskriftsartikel (refereegranskat)abstract
- Affibody (R) molecules are a class of small and robust affinity proteins that can be generated to interact with a variety of antigens, thus having the potential to provide useful tools for biotechnological research and diagnostic applications. In this study, we have investigated Affibody-based reagents interacting specifically with the tyrosine kinase receptor HER2. A head-to-tail dimeric construct was site-specifically conjugated with different fluorescent and enzymatic groups resulting in reagents that were used for detection and quantification. The amount of cell surface expressed HER2 oil eleven (11) well characterized cell lines was quantified relative to each other by flow cytometry and shown to correlate well with results from parallel analyses of HER2 mRNA levels measured by real-time PCR. Further, immunofluorescence I microscopy studies of the cell lines and immunohistochemical analyses of cryosections of HER2 expressing SKOV-3 xenografts showed strong staining of the plasma membrane of tumor cells with little background staining. Full-length HER2 protein Could also be efficiently recovered from a cell extract by an immunoprecipitation procedure, using an Affibody ligand-based resin. These novel non-IgG derived reagents could be used to detect and quantify HER2 expression. By adapting the methods for use with Affibody molecules binding to other cell surface receptors, it is anticipated that also these receptors can be detected and quantified in a similar manner.
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| 33. |
- Mercier, Bertrand, et al.
(författare)
-
Sensor Networks for Cognitive Radio: Theory and System Design
- 2008
-
Ingår i: Proceedings of the ICT Mobile and Wireless Communications Summit (ICT'08).
-
Konferensbidrag (refereegranskat)abstract
- Following current trends towards dynamic spectrum allocation and cognitive radio, this paper proposes a new approach and innovative techniques to support the coexistence of licensed and unlicensed wireless users in a same area. Theproposed concept, called Sensor Network aided Cognitive Radio, consists of a wireless sensor network able to assist the cognitive network by providing information on the current spectrum occupancy. This concept, that will address various operational scenarios in the future networks, involves a set of advanced wireless communications techniques like spectrum sensing, interference management, cognitive radio reconfiguration management, cooperative communications, end-to-end protocol design and cross-layer optimisation. All these enabling techniques together will form a compound system able to improve the spectrum use in a significant way. The main target scenario we consider is the use of nomadic cognitive radios in urban and suburban areas. Our objective is to develop a proof-of-concept – scheduled in 2010 – of the Sensor Network aided Cognitive Radio technology by implementing such techniques and integrating them on a hardware radio platform, which will allow us to assess the efficiency of the technology in a realistic environment.
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| 34. |
- Mitradjieva-Daneva, Maria, 1974-
(författare)
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Feasible Direction Methods for Constrained Nonlinear Optimization : Suggestions for Improvements
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns the development of novel feasible direction type algorithms for constrained nonlinear optimization. The new algorithms are based upon enhancements of the search direction determination and the line search steps.The Frank-Wolfe method is popular for solving certain structured linearly constrained nonlinear problems, although its rate of convergence is often poor. We develop improved Frank--Wolfe type algorithms based on conjugate directions. In the conjugate direction Frank-Wolfe method a line search is performed along a direction which is conjugate to the previous one with respect to the Hessian matrix of the objective. A further refinement of this method is derived by applying conjugation with respect to the last two directions, instead of only the last one.The new methods are applied to the single-class user traffic equilibrium problem, the multi-class user traffic equilibrium problem under social marginal cost pricing, and the stochastic transportation problem. In a limited set of computational tests the algorithms turn out to be quite efficient. Additionally, a feasible direction method with multi-dimensional search for the stochastic transportation problem is developed.We also derive a novel sequential linear programming algorithm for general constrained nonlinear optimization problems, with the intention of being able to attack problems with large numbers of variables and constraints. The algorithm is based on inner approximations of both the primal and the dual spaces, which yields a method combining column and constraint generation in the primal space.
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| 35. |
- Nyberg, Lars, et al.
(författare)
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Comparing 1,5T and 3T BOLD fMRI imaging of finger tapping with familiar and novel sequences.
- 2007
-
Ingår i: Neuroscience Imaging. - 1556-4010. ; 2:1, s. 53-64
-
Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that fMRI at 3T yields stronger and more extensive BOLD activations than fMRI at 1.5T, and that imaging at higher field strengths can reveal unique activations. In the present study we compared, within-subjects, activation patterns during a finger-tapping task at 1.5 and 3T. The data were analyzed with a random-effects model in SPM2. At a strict statistical level (p<0.05, FWE correction for multiple comparisons), ipsilateral cerebellar activation was revealed at 1.5T. At 3T, activation in sensory-motor regions in the contra-lateral cerebrum was identified in addition to the activation in cerebellum. At a less stringent statistical threshold, imaging at 1.5T and 3T revealed overlapping cortical regions with more extensive clusters at 3T. A similar pattern was seen in a comparison of familiar and novel sequences. However, subcortical activations of thalamus and parts of the basal ganglia were uniquely identified at 3T. Analyses at the individual level substantiated the group results by showing that the higher sensitivity of the 3T resulted in images with higher between-individual consistency in activation patterns.
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| 36. |
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| 37. |
- Olofsson, Christina, et al.
(författare)
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A multicenter clinical study of the safety and activity of maleimide-polyethylene glycol-modified Hemoglobin (Hemospan) in patients undergoing major orthopedic surgery.
- 2006
-
Ingår i: Anesthesiology. - : Ovid Technologies (Wolters Kluwer Health). - 0003-3022 .- 1528-1175. ; 105:6, s. 1153-63
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hemospan (Sangart Inc., San Diego, CA), a polyethylene glycol-modified hemoglobin with unique oxygen transport properties, has successfully completed a phase I trial in healthy volunteers. Because adverse events are expected to increase with age, the authors conducted a phase II safety study of Hemospan in elderly patients undergoing elective hip arthroplasty during spinal anesthesia. METHODS: Ninety male and female patients, American Society of Anesthesiologists physical status I-III, aged 50-89 yr, in six Swedish academic hospitals were randomly assigned to receive either 250 or 500 ml Hemospan or Ringer's acetate (30 patients/group) before induction of spinal anesthesia. Safety assessment included vital signs and Holter monitoring from infusion to 24 h, evaluation of laboratory values, and fluid balance. The hypothesis to be tested was that the incidence of adverse events would be no more frequent in patients who received Hemospan compared with standard of care (Ringer's acetate). RESULTS: Three serious adverse events were noted, none of which was deemed related to study treatment. Liver enzymes, amylase, and lipase increased transiently in patients in all three groups. There were no significant differences in electrocardiogram or Holter parameters, but there was a suggestion of more bradycardic events in the treated groups. Hypotension was less frequent in the treated patients compared with controls. CONCLUSIONS: In comparison with Ringer's acetate, Hemospan mildly elevates hepatic enzymes and lipase and is associated with less hypotension and more bradycardic events. The absence of a high frequency of serious adverse events suggests that further clinical trials should be undertaken.
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| 38. |
- Palmgren, Myrna, 1970-
(författare)
-
Optimal Truck Scheduling : Mathematical Modeling and Solution by the Column Generation Principle
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We consider the daily transportation problem in forestry which arises when transporting logs from forest sites to customers such as sawmills and pulp and paper mills. Each customer requires a specific amount of a certain assortment, and the deliveries to the customers can be made within time intervals, known as time windows. Further, there are a number of supply points, each with a certain assortment, and a number of vehicles of a given capacity, to be used for transport.The log truck scheduling problem consists of finding a set of minimal costs routes, one for each vehicle, such that the customers’ demands are satisfied without exceeding the supplies available at the supplies. Each route has to satisfy a number of constraints concerning time windows, truck capacity, timetable of the driver, lunch breaks, et cetera. The model used to describe the log truck scheduling problem is based on the route concept, and each variable, or column, represents one feasible route. Since the number of feasible routes is huge, we work only with restricted versions of this problem, which are similar to restricted master problems in a Dantzig-Wolfe decomposition scheme.We use three solution methods based on the column generation principle, together with a pool strategy which allows us to deal with the feasible routes outside the restricted master problem. The three methods proposed have a common structure; they use branch-andprice together with a column generator, followed by branch-and-bound. The column generators in the three methods differ. In the first method, the subproblem is based on a cluster-first-route-second strategy. The column generator in the second method involves solving a constrained shortest path problem, and finally, the third method builds on a repeated generation of clusters and routes.The three methods are tested on real cases from Swedish forestry companies, and the third method has been adapted to a computerised system that utilises the Swedish national road data base, for computing travelling distances. The results obtained show that the optimisation methods succeed in finding significantly better solutions than those obtained by manual planning, and in a reasonable computing time.
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| 39. |
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| 40. |
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| 41. |
- Peterson, Anders, 1976-
(författare)
-
The Origin-Destination Matrix Estimation Problem : Analysis and Computations
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- For most kind of analyses in the field of traffic planning, there is a need for origin--destination (OD) matrices, which specify the travel demands between the origin and destination nodes in the network. This thesis concerns the OD-matrix estimation problem, that is, the calculation of OD-matrices using observed link flows. Both time-independent and time-dependent models are considered, and we also study the placement of link flow detectors.Many methods have been suggested for OD-matrix estimation in time-independent models, which describe an average traffic situation. We assume a user equilibrium to hold for the link flows in the network and recognize a bilevel structure of the estimation problem. A descent heuristic is proposed, in which special attention is given to the issue of calculating the change of a link flow with respect to a change of the travel demand in a certain pair of origin and destination nodes.When a time-dimension is considered, the estimation problem becomes more complex. Besides the problem of distributing the travel demand onto routes, the flow propagation in time and space must also be handled. The time-dependent OD-matrix estimation problem is the subject for two studies. The first is a case study, where the conventional estimation technique is improved through introducing pre-adjustment schemes, which exploit the structure of the information contained in the OD-matrix and the link flow observations. In the second study, an algorithm for time-independent estimation is extended to the time-dependent case and tested for a network from Stockholm, Sweden.Finally, we study the underlying problem of finding those links where traffic flow observations are to be performed, in order to ensure the best possible quality of the estimated OD-matrix. There are different ways of quantifying a common goal to cover as much traffic as possible, and we create an experimental framework in which they can be evaluated. Presupposing that consistent flow observations from all the links in the network yields the best estimate of the OD-matrix, the lack of observations from some links results in a relaxation of the estimation problem, and a poorer estimate. We formulate the problem to place link flow detectors as to achieve the least relaxation with a limited number of detectors.
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| 42. |
- Rönnberg, Elina, 1981-, et al.
(författare)
-
An All-Integer Column Generation Methodology for Set Partitioning Problems
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The set partitioning polytope has the quasi-integrality propertythat enables the use of simplex pivot based methods for finding animproved integer solution, which thereby is associated with a linearprogramming basis and a corresponding dual solution. Presented in thispaper is a framework for an all-integer column generation methodologyfor set partitioning problems that utilises the quasi-integralityproperty of the feasible polytope.In the presented methodology, each successively found solution to arestricted master problem is feasible, integer and associated with acorresponding dual solution, which is then used in the columngeneration step. The column generation problem is tailored to producecolumns that maintain integrality when pivoted into the basis.Furthermore, criteria for verifying optimality are presented.
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| 43. |
- Rönnberg, Elina, 1981-, et al.
(författare)
-
Automating the Self-Scheduling Process of Nurses in Swedish Healthcare : A Pilot Study
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Hospital wards need to be staffed by nurses round the clock, resultingin irregular working hours for many nurses. Over the years, thenurses' influence on the scheduling have been increased in order toimprove their working conditions. In Sweden it is common to apply a kindof self-scheduling where each nurse individually proposes a schedule,and then the final schedule is determined through informalnegotiations between the nurses. This kind of self-scheduling is verytime-consuming and does often lead to conflicts.We present a pilot study which aims at determining if it is possibleto create an optimisation tool that automatically delivers a usableschedule based on the schedules proposed by the nurses. The study isperformed at a typical Swedish nursing ward, for which we havedeveloped a mathematical model and delivered schedules. The results ofthis study are very promising.
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| 44. |
- Rönnberg, Elina, 1981-, et al.
(författare)
-
Column Generation in the Integral Simplex Method
- 2009
-
Ingår i: European Journal of Operational Research. - : Elsevier. - 0377-2217 .- 1872-6860. ; 192:1, s. 333-342
-
Tidskriftsartikel (refereegranskat)abstract
- The integral simplex method for set partitioning problems allows onlypivots-on-one to be made, which results in a primal all-integer method. Inthis technical note we outline how to tailor the column generationprinciple to this method. Because of the restriction topivots-on-one, only local optimality can be guaranteed, and to ensureglobal optimality we consider the use of implicit enumeration.
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| 45. |
- Rönnberg, Elina, 1981-
(författare)
-
Methods and Applications in Integer Programming : All-Integer Column Generation and Nurse Scheduling
- 2008
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Integer programming can be used to provide solutionsto complex decision and planning problems occurring in a wide varietyof situations. Applying integer programming to a real life problembasically involves a first phase where a mathematical model isconstructed, and a second phase where the problem described by themodel is solved. While the nature of the challenges involved in therespective two phases differ, the strong relationship between theproperties of models, and which methods that are appropriate for theirsolution, links the two phases. This thesis constitutes of threepapers, of which the third one considers the modeling phase, while thefirst and second one consider the solution phase. Many applications of column generation yield master problems of setpartitioning type, and the first and second papers presentmethodologies for solving such problems. The characteristics of themethodologies presented are that all successively found solutions arefeasible and integral, where the retention of integrality is a majordistinction from other column generation methods presented in theliterature. The third paper concerns nurse scheduling and describes the results ofa pilot implementation of a scheduling tool at a Swedish nursing ward.This paper focuses on the practical aspects of modeling and thechallenges of providing a solution to a complex real life problem.
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| 46. |
- Sahlin, Fredrik, et al.
(författare)
-
Two-Dimensional CFD-Analysis of Micro-Patterned Surfaces in Hydrodynamic Lubrication
- 2005
-
Ingår i: Journal of tribology. - : ASME International. - 0742-4787 .- 1528-8897. ; 127:1, s. 96-102
-
Tidskriftsartikel (refereegranskat)abstract
- Results of a numerical study of the influence of micro-patterned surfaces in hydrodynamic lubrication of two parallel walls are reported. Two types of parameterized grooves with the same order of depth as the film thickness are used on one stationary wall. The other wall is smooth and is sliding with a specified tangential velocity Isothermal incompressible two dimensional full film fluid flow mechanics is solved using a Computational Fluid Dynamics method. It is shown that, by introducing a micro-pattern on one of two parallel walls, a net pressure rise in the fluid domain is achieved. This produces a load carrying capacity on the walls which is mainly contributed by fluid inertia. The load carrying capacity increases with Reynolds number The load carrying capacity is reported to increase with groove width and depth. However at a certain depth a vortex appears in the groove and near this value the maximum load carrying capacity is achieved. It is shown that the friction force decreases with deeper and wider grooves. Among all geometries studied, optimum geometry shapes in terms of hydrodynamic performance are reported.
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| 47. |
- Sundström, Torbjörn, et al.
(författare)
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Memory-provoked rCBF-SPECT as a diagnostic tool in Alzheimer's disease?
- 2006
-
Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 33:1, s. 73-80
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Alzheimer's disease (AD) is a primary degenerative disease that progressively affects all brain functions, with devastating consequences for the patient, the patient's family and society. Rest regional cerebral blood flow (rCBF) could have a strategic role in differentiating between AD patients and normal controls, but its use for this purpose has a low discriminatory capacity. The purpose of this study was to evaluate whether the diagnostic sensitivity of rCBF single-photon emission computed tomography (SPECT) could be increased by using an episodic memory task provocation, i.e. memory-provoked rCBF-SPECT (MP-SPECT). METHODS: Eighteen persons (73.2+/-4.8 years) with mild AD and 18 healthy elderly (69.4+/-3.9 years) were included in the study. The subjects were injected with (99m)Tc-hexamethylpropylene amine oxime (HMPAO) during memory provocation with faces and names, followed by an rCBF-SPECT study. The rCBF (99m)Tc-HMPAO SPECT images were analysed using statistical parametric mapping (SPM2). Peaks with a false discovery rate corrected value of 0.05 were considered significant. RESULTS: On MP-SPECT, the AD group showed a significant rCBF reduction in the left parietal cortex in comparison with healthy elderly. At rest, no significant group differences were seen. CONCLUSION: Memory provocation increased the sensitivity of rCBF-SPECT for the detection of AD-related blood flow changes in the brain at the group level. Further studies are needed to evaluate MP-SPECT as a diagnostic tool at the individual level. If a higher sensitivity for AD at the individual level is verified in future studies, a single MP-SPECT study might be sufficient in the clinical setting.
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| 48. |
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| 49. |
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| 50. |
- Westerberg, Per-Anton, et al.
(författare)
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Preoperative tumor localization by means of venous sampling for fibroblast growth factor-23 in a patient with tumor-induced osteomalacia
- 2008
-
Ingår i: Endocrine Practice. - 1530-891X .- 1934-2403. ; 14:3, s. 362-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To report on a novel strategy for tumor localization in a 62-year-old man with hypophosphatemic tumor-induced osteomalacia (TIO). METHODS: Repeated computed tomographic and magnetic resonance imaging scans failed to localize any tumor in a patient with adult-onset hypophosphatemic osteomalacia. Therefore, venous sampling for fibroblast growth factor-23 (FGF23)--a circulating hormone that has been identified as a causative factor for TIO--in major veins was conducted. Serum FGF23 was measured from collected samples by an intact FGF23 enzyme-linked immunosorbent assay. RESULTS: Venous sampling suggested a local increase in serum FGF23 in the left femoral vein; this finding prompted performance of octreotide scintigraphy restricted to the left leg. A tumor was located at the lateral condyle of the left femur, which was also confirmed by magnetic resonance imaging. Surgical resection of the tumor normalized the serum phosphorus and 1,25-dihydroxyvitamin D3 levels within 5 to 10 days, and FGF23 declined to normal levels within 24 hours. Histologic analysis supported the diagnosis of a soft-tissue giant cell tumor. CONCLUSION: Our study case demonstrates the diagnostic complexity and difficulties in localizing a small tumor in a patient with TIO. Venous sampling for FGF23 may be helpful in tumor localization in sporadic cases of hypophosphatemic osteomalacia, especially when noninvasive diagnostic techniques prove insufficient.
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