| 1. |
- Leonard, Dag, et al.
(författare)
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Coronary Heart Disease in Systemic Lupus Erythematosus Is Associated With Interferon Regulatory Factor-8 Gene Variants
- 2013
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Ingår i: Circulation: Cardiovascular Genetics. - : BMJ. - 1942-325X .- 1942-3268. ; 72:Suppl. 3, s. 270-270
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Tidskriftsartikel (refereegranskat)abstract
- Background- Patients with systemic lupus erythematosus have increased morbidity and mortality in coronary heart disease (CHD). We asked whether there was a genetic influence on CHD in systemic lupus erythematosus. Methods and Results- The association between single-nucleotide polymorphisms (SNPs) and CHD in 2 populations of patients with systemic lupus erythematosus was assessed. Patients were genotyped on a custom 12k Illumina Array. The allele frequencies were compared between patients with (n=66) and without (n=509) CHD. We found 61 SNPs with an association (P<0.01) to CHD, with the strongest association for 3 SNPs located in the interferon regulatory factor-8 (IRF8) gene. Comparison of the allele frequencies of these 61 SNPs in patients with (n=27) and without (n=212) CHD in the second study population revealed that 2 SNPs, rs925994 and rs10514610 in IRF8 (linkage disequilibrium, r(2)=0.84), were associated with CHD in both study populations. Meta-analysis of the SNP rs925994 gave an odds ratio of 3.6 (2.1-6.3), P value 1.9x10(-6). The identified IRF8 allele remained as a risk factor for CHD after adjustment for traditional CHD risk factors. The IRF8 risk allele was associated with the presence of carotid plaques (P<0.001) and increased intima-media thickness (P=0.01). By electrophoretic mobility shift assays, we show weaker binding of protein to the risk allele of the highly linked SNP rs11117415, and by flow cytometry, a reduced frequency of circulating B cells was detected in patients with the IRF8 risk allele. Conclusions- There is a considerable genetic component for CHD in systemic lupus erythematosus, with IRF8 as a strong susceptibility locus.
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| 2. |
- Bengtsson, Olof, 1969-
(författare)
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Design and Characterization of RF-Power LDMOS Transistors
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In mobile communication new applications like wireless internet and mobile video have increased the demand of data-rates. Therefore, new more wideband systems are being implemented. Power amplifiers in the base-stations that simultaneously handle these wideband signals for many terminals (handhelds) need to be highly linear with a considerable band-width. In the past decade LDMOS has been the dominating technology for use in these RF-power amplifiers. In this work LDMOS transistors possible to fabricate in a normal CMOS process have been optimized and analyzed for RF-power applications. Their non-linear behavior has been explored using load-pull measurements. The mechanisms of the non-linear input capacitance have been analyzed using 2D TCAD simulations. The investigation shows that the input capacitance is a large contributor to phase distortion in the transistor. Computational load-pull TCAD methods have been developed for analysis of RF-power devices in high-efficiency operation. Methods have been developed for class-F with harmonic loading and for bias-modulation. Load-pull measurements with drain-bias modulation in a novel measurement setup have also been conducted. The investigation shows that the combination of computational load-pull of physical transistor structures and direct measurement evaluation with modified load-pull is a viable alternative for future design of RF-power devices. Simulations and measurements on the designed LDMOS shows a 10 to 15 % increase in drain efficiency in mid-power range both in simulations and measurements. The computational load-pull method has also been used to investigate the power capability of LDMOS transistors on SOI. This study indicates that either a low-resistivity or high-resistivity substrate should be used in manufacturing of RF-power LDMOS transistors on SOI to achieve optimum efficiency. Based on a proper substrate selection these devices exhibit a 10 % higher drain-efficiency mainly due to lower dissipated power in the devices.
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| 3. |
- Berntsson Svensson, Richard, 1978-, et al.
(författare)
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BAM : backlog assessment method
- 2019
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Ingår i: Lecture Notes in Business Information Processing. - Cham : Springer Verlag. - 1865-1348. - 9783030190330 ; , s. 53-68
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Konferensbidrag (refereegranskat)abstract
- The necessity of software as stand-alone products, and as central parts of non-traditional software products have changed how software products are developed. It started with the introduction of the agile manifesto and has resulted in a change of how software process improvements (SPI) are conducted. Although there are agile SPI methods and several agile practices for evaluating and improving current processes and ways-of-working, no method or practices for evaluating the backlog exists. To address this gap, the Backlog Assessment Method (BAM) was developed and applied in collaboration with Telenor Sweden. BAM enables agile organizations to assess backlogs, and assure that the backlog items are good-enough for their needs and well aligned with the decision process. The results from the validation show that BAM is feasible and relevant in an industrial environment, and it indicates that BAM is useful as a tool to perform analysis of items in a specific backlog. © The Author(s) 2019.
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| 4. |
- Hjelm-Wallén, Lena, et al.
(författare)
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Det behövs mer än värnplikt
- 2016
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Ingår i: Svenska dagbladet. - 1101-2412. ; :2016-10-07, s. 6-6
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Människors säkerhet handlar om mycket mer än det rent militära. Därför är det är dags att överväga att införa allmän medborgartjänst för alla medborgare kring tjugoårsåldern.
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| 5. |
- Jackson, Alice M., et al.
(författare)
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Dapagliflozin and Diuretic Use in Patients With Heart Failure and Reduced Ejection Fraction in DAPA-HF.
- 2020
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Ingår i: Circulation. - 1524-4539. ; 142:11, s. 1040-1054
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In the DAPA-HF trial (Dapagliflozin and Prevention of Adverse-Outcomes in Heart Failure), the sodium-glucose cotransporter 2 inhibitor dapagliflozin reduced the risk of worsening heart failure and death in patients with heart failure and reduced ejection fraction. We examined the efficacy and tolerability of dapagliflozin in relation to background diuretic treatment and change in diuretic therapy after randomization to dapagliflozin or placebo. METHODS: We examined the effects of study treatment in the following subgroups: no diuretic and diuretic dose equivalent to furosemide $<$40, 40, and $>$40 mg daily at baseline. We examined the primary composite end point of cardiovascular death or a worsening heart failure event and its components, all-cause death and symptoms. RESULTS: Of 4616 analyzable patients, 736 (15.9%) were on no diuretic, 1311 (28.4%) were on $<$40 mg, 1365 (29.6%) were on 40 mg, and 1204 (26.1%) were taking $>$40 mg. Compared with placebo, dapagliflozin reduced the risk of the primary end point across each of these subgroups: hazard ratios were 0.57 (95% CI, 0.36-0.92), 0.83 (95% CI, 0.63-1.10), 0.77 (95% CI, 0.60-0.99), and 0.78 (95% CI, 0.63-0.97), respectively (P for interaction=0.61). The hazard ratio in patients taking any diuretic was 0.78 (95% CI, 0.68-0.90). Improvements in symptoms and treatment toleration were consistent across the diuretic subgroups. Diuretic dose did not change in most patients during follow- up, and mean diuretic dose did not differ between the dapagliflozin and placebo groups after randomization. CONCLUSIONS: The efficacy and safety of dapagliflozin were consistent across the diuretic subgroups examined in DAPA-HF. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03036124.
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| 6. |
- Rosell, Johan, et al.
(författare)
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Effects of adjuvant tamoxifen therapy on the incidence of secondary cancer : results from a randomized trial with long term follow-up
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUNDTamoxifen is a well-established endocrine treatment for breast cancer. We here present results with respect to second primary cancer from a large randomized trial of 5 and 2 years of adjuvant tamoxifen. Breast cancer distant recurrence and mortality are also reported.METHODSOur study included 4128 postmenopausal patients with early stage breast cancer who were alive and free of breast cancer recurrence after 2 years of tamoxifen therapy. They were randomized to receive three more years of therapy or stop tamoxifen. In the comparison of 5 years versus 2 years of postoperative tamoxifen treatment hazard ratios were estimated using Cox regression for different follow-up periods defined as: During treatment (2-5 years) and after treatment (5-10 years, 10-15 years, > 5 years, > 10 years and > 15 years).RESULTSIn the five years group the incidence of lung cancer was halved (hazard ratio [HR], 0.45, 95% confidence interval [95% CI], 0.27-0.77 [P = .0038]), and lung cancer mortality was decreased. An increased risk was observed for endometrial cancer (HR, 1.83; 95% CI, 1.19-2.81 [P = .0059]), but this risk appeared to decrease over time. The risk of contralateral breast cancer was decreased (HR, 0.73; 95% CI, 0.56-0.96 [P = .022]), also in the period after treatment stopped. In the five years group, the risk of distant recurrence was decreased, and statistically significant reductions were observed both during treatment and in the five year period after treatment stopped. The breast cancer mortality was reduced, especially during the post-treatment phase.CONCLUSIONSIn this randomized study, tamoxifen substantially reduces the risk of new cancer both in contralateral breast and in lung up to 10 years after treatment stopped.
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| 7. |
- Rosell, Johan, et al.
(författare)
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Long-term effects on the incidence of second primary cancers in a randomized trial of two and five years of adjuvant tamoxifen
- 2017
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Ingår i: Acta Oncologica. - : Taylor & Francis. - 0284-186X .- 1651-226X. ; 56:4, s. 614-617
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tamoxifen is a well established treatment for breast cancer, but its long-term effects on the incidence of secondary cancers are not fully evaluated.Material and methods: We have studied 4128 postmenopausal patients with early stage breast cancer who were alive and free of breast cancer recurrence after two years of tamoxifen, and who were randomized to receive totally two or five years of therapy.Results: Compared to patients randomized to two years of tamoxifen the incidence of contralateral breast cancer [hazard ratio (HR) 0.73; 95% CI 0.56-0.96] and of lung cancer (HR 0.45; 95% CI 0.27-0.77), especially squamous cell and small cell lung cancer, were reduced in the five-year group, and similar results were seen when restricting the analysis to the 10-year period after treatment stopped. An increased incidence of endometrial cancer was observed in the five-year group, but the excess risk decreased over time.Conclusion: Further studies of the effects of tamoxifen on the risk of different histological types of lung cancer are needed.
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| 8. |
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| 9. |
- Adamson, Carly, et al.
(författare)
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Efficacy of Dapagliflozin in Heart Failure with Reduced Ejection Fraction According to Body Mass Index.
- 2021
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Ingår i: European journal of heart failure. - : Wiley. - 1388-9842 .- 1879-0844. ; 23:10, s. 1662-1672
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: In heart failure with reduced ejection fraction (HFrEF), there is an ’obesity paradox’, where survival is better in patients with a higher body mass index (BMI) and weight loss is associated with worse outcomes. We examined the effect of a sodium-glucose co-transporter 2 inhibitor according to baseline BMI in the Dapagliflozin And Prevention of Adverse- outcomes in Heart Failure trial (DAPA-HF). METHODS AND RESULTS: Body mass index was examined using standard categories, i.e. underweight ($<$18.5 kg/m(2) ); normal weight (18.5-24.9 kg/m(2) ); overweight (25.0-29.9 kg/m(2) ); obesity class I (30.0-34.9 kg/m(2) ); obesity class II (35.0-39.9 kg/m(2) ); and obesity class III ($>$/=40 kg/m(2) ). The primary outcome in DAPA-HF was the composite of worsening heart failure or cardiovascular death. Overall, 1348 patients (28.4%) were under/normal- weight, 1722 (36.3%) overweight, 1013 (21.4%) obesity class I and 659 (13.9%) obesity class II/III. The unadjusted hazard ratio (95% confidence interval) for the primary outcome with obesity class 1, the lowest risk group, as reference was: under/normal-weight 1.41 (1.16-1.71), overweight 1.18 (0.97-1.42), obesity class II/III 1.37 (1.10-1.72). Patients with class I obesity were also at lowest risk of death. The effect of dapagliflozin on the primary outcome and other outcomes did not vary by baseline BMI, e.g. hazard ratio for primary outcome: under/normal-weight 0.74 (0.58-0.94), overweight 0.81 (0.65-1.02), obesity class I 0.68 (0.50-0.92), obesity class II/III 0.71 (0.51-1.00) (P-value for interaction = 0.79). The mean decrease in weight at 8 months with dapagliflozin was 0.9 (0.7-1.1) kg (P $<$ 0.001). CONCLUSION: We confirmed an ’obesity survival paradox’ in HFrEF. We showed that dapagliflozin was beneficial across the wide range of BMI studied. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT03036124.
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| 10. |
- Adamson, Carly, et al.
(författare)
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Liver Tests and Outcomes in Heart Failure with Reduced Ejection Fraction : Findings from DAPA-HF.
- 2022
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Ingår i: European journal of heart failure. - : Wiley. - 1388-9842 .- 1879-0844. ; 24:10, s. 1856-1868
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Reflecting both increased venous pressure and reduced cardiac output, abnormal liver tests are common in patients with severe heart failure and are associated with adverse clinical outcomes. We aimed to investigate the prognostic significance of abnormal liver tests in ambulatory patients with heart failure with reduced ejection fraction (HFrEF), explore any treatment interaction between bilirubin and sodium- glucose cotransporter 2 (SGLT2) inhibitors and examine change in liver tests with SGLT2 inhibitor treatment. METHODS AND RESULTS: We explored these objectives in the Dapagliflozin And Prevention of Adverse outcomes in Heart Failure (DAPA-HF) trial, with focus on bilirubin. We calculated the incidence of cardiovascular death or worsening heart failure by bilirubin tertile. Secondary cardiovascular outcomes were examined, along with the change in liver tests at the end-of-study visit. Baseline bilirubin was available in 4720 patients (99.5%). Participants in the highest bilirubin tertile (T3) have more severe HFrEF (lower left ventricular ejection fraction, higher N-terminal pro-B-type natriuretic peptide [NT-proBNP] and worse New York Heart Association class), had a greater burden of atrial fibrillation but less diabetes. Higher bilirubin (T3 vs. T1) was associated with worse outcomes even after adjustment for other predictive variables, including NT-proBNP and troponin T (adjusted hazard ratio for the primary outcome 1.73 [95% confidence interval 1.37-2.17], p $<$ 0.001; and 1.52 [1.12-2.07], p = 0.01 for cardiovascular death). Baseline bilirubin did not modify the benefits of dapagliflozin. During follow-up, dapagliflozin had no effect on liver tests. CONCLUSION: Bilirubin concentration was an independent predictor of worse outcomes but did not modify the benefits of dapagliflozin in HFrEF. Dapagliflozin was not associated with change in liver tests. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT03036124.
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| 11. |
- Ahrné, Karin, et al.
(författare)
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Rödlista över fjärilar Lepidoptera
- 2015
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Ingår i: Rödlistade arter i Sverige 2015. - Uppsala : ArtDatabanken SLU. - 9789187853104 ; , s. 98-112
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 12. |
- Arnestad, J P, et al.
(författare)
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Isolated hyperthermic liver perfusion with cytostatic-containing perfusate activates the complement cascade.
- 1992
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Ingår i: The British journal of surgery. - 0007-1323. ; 79:9, s. 948-51
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Tidskriftsartikel (refereegranskat)abstract
- Eight patients with advanced liver malignancy undergoing isolated hyperthermic liver perfusion with melphalan and cisplatin were studied with regard to complement activation and formation of anaphylatoxins (C3a and C5a) and terminal C5b-9 complement complexes (TCCs). Blood samples for complement variables (C1-INH, C3, C4, C5, C3a, C5a and TCCs) were taken before surgery, 1 min before the start of perfusion, 1, 2 and 3 h after the start of perfusion, and 24 h after operation. Samples were drawn from the perfusate 1 h after the start of perfusion. Activation of complement was observed during perfusion. Raised plasma concentrations of C3a and TCCs were recorded and high levels of C3a and TCCs were found in the perfusate. In vitro tests indicated that melphalan and cisplatin may activate complement. This activation occurred at 37 and 42 degrees C but was more pronounced at 42 degrees C.
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| 13. |
- Asp, Mihaela, et al.
(författare)
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The role of computed tomography in the assessment of tumour extent and the risk of residual disease after upfront surgery in advanced ovarian cancer (AOC)
- 2022
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Ingår i: Archives of Gynecology and Obstetrics. - : Springer Science and Business Media LLC. - 1432-0711.
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Tidskriftsartikel (refereegranskat)abstract
- PurposeEpithelial ovarian cancer is usually diagnosed in the advanced stages. To choose the best therapeutic approach, an accurate preoperative assessment of the tumour extent is crucial. This study aimed to determine whether the peritoneal cancer index (PCI), the amount of ascites, and the presence of cardiophrenic nodes (CPLNs) visualized by computed tomography (CT) can assess the tumour extent (S-PCI) and residual disease (RD) for advanced ovarian cancer (AOC) patients treated with upfront surgery.MethodsIn total, 118 AOC cases were included between January 2016 and December 2018 at Skåne University Hospital, Lund, Sweden. Linear regression and interclass correlation (ICC) analyses were used to determine the relationship between CT-PCI and S-PCI. The patients were stratified in complete cytoreductive surgery (CCS) with no RD or to non-CCS with RD of any size. The amount of ascites on CT (CT-ascites), CA-125 and the presence of radiological enlarged CPLNs (CT-CPLN) were analysed to evaluate their impact on estimating RD.ResultsCT-PCI correlated well with S-PCI (0.397; 95% CI 0.252–0.541; p < 0.001). The risk of RD was also related to CT-PCI (OR 1.069 (1.009–1.131), p < 0.023) with a cut-off of 21 for CT-PCI (0.715, p = 0.000). The sensitivity, specificity, positive predictive value and negative predictive value were 58.5, 70.3, 52.2 and 75.4%, respectively. CT-ascites above 1000 ml predicted RD (OR 3.510 (1.298–9.491) p < 0.013).ConclusionCT is a reliable tool to assess the extent of the disease in advanced ovarian cancer. Higher CT-PCI scores and large volumes of ascites estimated on CT predicted RD of any size.
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| 14. |
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| 15. |
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| 16. |
- Bengtsson, Hans, et al.
(författare)
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Development of Parent‐Young Interaction in Asynchronously Hatched Broods of Altricial Birds
- 1981
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Ingår i: Zeitschrift fuer Tierpsychologie / Journal of Comparative ethology. ; 56:3, s. 255-272
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Tidskriftsartikel (refereegranskat)abstract
- In bird species which have developed a brood reduction strategy, initial inequality among siblings is established through asynchronous hatching. After hatching, the maintenance of a weight hierarchy within the brood and its spread is governed by the allocation of feeds to the chicks and by the rate of parental feeding. In the present study, the initiation of parental feeding and subsequent changes in the feeding procedure were studied in asynchronously hatched broods of the great tit Parus major and the blackbird Turdus merula. During the period of hatching the brood was roused by a parental feeding call on most visits to the nest which made feeding niore effective. Late-hatched young initially increased their chances to receive feeding offers by showing a high rate of spontaneous begging. In addition, they were more dependent than the older young on a high rate of mobility in order to be fed and they showed increasing mobility with age. Crucial changes in the feeding procedure took place at the end of the hatching period when the parents ceased to emit feeding calls and in the last few days before the abandonment of the nest when the biggest young started to jump towards the parents at feeding. These periods were identified as critical for late-hatched young. We argue that parental feeding rate is a feature of parent-young interaction that develops in order to adapt parental investment in individual nestlings to changes in food conditions when the brood is being raised.
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| 17. |
- Bengtsson, Hans, et al.
(författare)
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Parental feeding rate in relation to begging behavior in asynchronously hatched broods of the great tit Parus major: An experimental study.
- 1983
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Ingår i: Behavioral Ecology and Sociobiology. - 1432-0762. ; 12:3, s. 243-251
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Tidskriftsartikel (refereegranskat)abstract
- Four experiments manipulated the stimulus situation encountered by great tits on their feeding visits to the brood in order to explore its effect on feeding rate. Three broods containing 8, 8, and 10 nestlings were studied. A higher feeding rate was observed under the following conditions: (1) after a period of food deprivation, as compared with normal conditions and satiation through artifical feeding; (2) in periods when recorded begging calls were played during feeding visits, as compared with control periods; and (3) after temporary removal from the nest of heavier, as compared with lighter, siblings. The lighter nestlings benefitted more (in terms of weight gain) from the increase in parental feeding rate following the playing of begging calls than did the heavier nestlings. Differences in weight within broods did not affect the amount of food the parents brought. It is concluded that parental feeding rate is affected not simply by the begging of the hungriest nestling but rather by the behavior of all the nestlings, which makes possible an adjustment of the feeding rate to the average hunger level of the brood.
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| 18. |
- Bengtsson, Ingemar, et al.
(författare)
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Light cone actions for gravity and higher spins: some further results
- 1983
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- It has been suggested that field theories for arbitrary spin can be defined,using the light front formulation of dynamics. The higher order termsin the actions are discussed in this paper. We show that the gravity actioncan be written without ``time''-derivatives in the interaction termsin a way which appears generalisable to higher spin. Some problems forhigher spins are identified and briefly discussed.
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| 19. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Bengtsson, Magnus Wilhelm, 1977-
(författare)
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Effects of Orexins, Guanylins and Feeding on Duodenal Bicarbonate Secretion and Enterocyte Intracellular Signaling
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The duodenal epithelium secretes bicarbonate ions and this is regarded as the primary defence mechanism against the acid discharged from the stomach. For an efficient protection, the duodenum must also function as a sensory organ identifying luminal factors. Enteroendocrine cells are well-established intestinal “taste” cells that express signaling peptides such as orexins and guanylins. Luminal factors affect the release of these peptides, which may modulate the activity of nearby epithelial and neural cells.The present thesis considers the effects of orexins and guanylins on duodenal bicarbonate secretion. The duodenal secretory response to the peptides was examined in anaesthetised rats in situ and the effects of orexin-A on intracellular calcium signaling by human as well as rat duodenal enterocytes were studied in vitro.Orexin-A, guanylin and uroguanylin were all stimulants of bicarbonate secretion. The stimulatory effect of orexin-A was inhibited by the OX1-receptor selective antagonist SB-334867. The muscarinic antagonist atropine on the other hand, did not affect the orexin-A-induced secretion, excluding involvement of muscarinic receptors. Orexin-A induced calcium signaling in isolated duodenocytes suggesting a direct effect at these cells. Interestingly, orexin-induced secretion and calcium signaling as well as mucosal orexin-receptor mRNA and OX1-receptor protein levels were all substantially downregulated in overnight fasted rats compared with animals with continuous access to food. Further, secretion induced by Orexin-A was shown to be dependent on an extended period of glucose priming.The uroguanylin-induced bicarbonate secretion was reduced by atropine suggesting involvement of muscarinic receptors. The melatonin receptor antagonist luzindole attenuated the secretory response to intra-arterially administered guanylins but had no effect on secretion when the guanylins were given luminally. In conclusion, the results suggest that orexin-A as well as guanylins may participate in the regulation of duodenal bicarbonate secretion. Further, the duodenal orexin system is dependent on the feeding status of the animals.
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| 26. |
- Bengtsson, Olof, et al.
(författare)
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A Computational Load-Pull Investigation of Harmonic Loading effects on AM-PM conversion
- 2008
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Ingår i: GigaHertz Symposium 2008. ; , s. 83-83
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this work computational harmonic load-pull have been used to study the effect of harmonic loading on AM-PM conversion for an RF-Power LDMOS transistor. It is found that especially the load impedance seen at the 2nd harmonic has a large impact (up to 2° or 15% difference) on the phase distortion at P1dB in this investigation conducted at chip level.
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| 27. |
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| 28. |
- Bengtsson, Olof, et al.
(författare)
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A Computational Load-Pull Method for TCAD Optimization of RF-Power Transistors in Bias-Modulation Applications
- 2008
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Ingår i: Proceedings of the 3rd European Microwave Integrated Circuits Conference. - 9782874870071
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Konferensbidrag (refereegranskat)abstract
- In this paper a method for TCAD evaluation of RF-Power transistors for high-efficiency operation using drain bias-modulation is presented. The method is based on large signal time-domain transient computational load-pull. With the method, intrinsic device parasitics and mechanisms affecting device efficiency under drain bias modulation can be investigated and optimized for the application making it very useful for RFIC design. A case study has been done on a CMOS compatible LDMOS. For verification under dynamic operation two-tone signals with varying envelope has been simulated. The results show a possible 15% increase in the efficiency of a modulated signal for the studied device at the expense of increased phase distortion observable also in the time-domain waveforms generated. Since the method is based on TCAD it is also useful in the investigation of e.g. dynamic breakdown during high envelope under bias-modulation operation.
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| 29. |
- Bengtsson, Olof, et al.
(författare)
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A Computational Load-Pull Method with Harmonic Loading for High-Efficiency Investigations
- 2009
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 53:1, s. 86-94
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Tidskriftsartikel (refereegranskat)abstract
- In this paper a method for TCAD evaluation of RF-power transistors in high-efficiency operation using harmonic loading is presented. The method is based on large signal time-domain computational load-pull. Active loads are used in the harmonic load-pull for simulation time reduction. With the method device performance under different harmonic load impedance can be investigated at an early stage in the design process. Alternative designs can be compared and the mechanisms affecting device efficiency in class-F can be studied at chip-level. For method validation, a case study is made on an LDMOS transistor. The transistor is load-pulled in class-AB and then optimized for efficiency at 2f0 and 3f0 using a novel approach with passive fundamental load and active harmonic loads. A swept simulation is conducted using passive fundamental and harmonic loads. Waveforms in compression are analyzed and the mechanisms creating the increased efficiency in class-F are identified by a comparative study to class-AB. Class-F harmonic termination is shown to give a 17% overall reduction of dissipated power and a 9% increase in output power. The expected efficiency increase is about 3–10% in the compression region depending on level of compression.
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| 30. |
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| 31. |
- Bengtsson, Olof, et al.
(författare)
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A Method for Device Intermodulation Analysis from 2D, TCAD Simulations using a Time-domain Waveform Approach
- 2006
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Ingår i: Proceedings of the 36th European Microwave Conference. ; , s. 169-171
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Konferensbidrag (refereegranskat)abstract
- This paper describes a fast method useful for IMD analysis at TCAD design level. The method is based on the static load-line transfer function extracted from 2D device simulations. The transfer function is exposed to a time domain signal through a look-up table and the output response is analyzed using the Fast Fourier Transform. The response is compared to measurements of a fabricated device. The method is shown to accurately predict the IMD behavior of a two-tone signal for the 3’rd, 5’th and 7’th order IMD products with regards to sweet spot tracking and relative IMD magnitude. We present a fast and simple way to predict IMD performance from TCAD simulations at an early stage in the design process. The method enables prediction of output response from any signal due to the time domain approach.
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| 35. |
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| 36. |
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| 37. |
- Bengtsson, Olof, et al.
(författare)
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Investigation of SOI-LDMOS for RF-power applications using Computational Load-Pull
- 2009
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Ingår i: IEEE Transactions on Electron Devices. - : IEEE. - 0018-9383 .- 1557-9646. ; 56:3, s. 505-511
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Tidskriftsartikel (refereegranskat)abstract
- Small-signal and computational load-pull simulations are used to investigate the effect of substrate resistivity on efficiency in high-power operation of high-frequency silicon-on-insulator-LDMOS transistors. Identical transistors are studied on substrates with different resistivities. Using computational load pull, their high-power performance is evaluated. The results are compared to previous investigations, relating the OFF-state output resistance to high-efficiency operation. From the large-signal simulation, an output circuit model based on a load-line match is extracted with parameters traceable from small-signal simulations. It is shown that, albeit high OFF-state output resistance is a good indication, it is not sufficient for high efficiency in a high-power operation. The bias and frequency dependence of the coupling through the substrate makes a more detailed ON-state analysis necessary. It is shown that very low resistivity and high-resistivity SOI substrates both result in a high efficiency at the studied frequency and bias point. It is also shown that a normally doped medium-resistivity substrate results in a significantly lower efficiency.
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| 38. |
- Bengtsson, Olof, et al.
(författare)
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Investigation of the non-linear input capacitance in LDMOS transistors and its contribution to IMD and phase distortion
- 2008
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 52:7, s. 1024-1031
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Tidskriftsartikel (refereegranskat)abstract
- In this paper the mechanisms causing the capacitive, reactive non-linearities in a lateral double diffused MOS, LDMOS, transistor are investigated. The non-linear input capacitance under load-line power match is extracted and analyzed. Computational TCAD load-pull is used to analyze the effect of non-linear capacitance on two-tone intermodulation distortion and AM–PM conversion in class-A operation. High-frequency measurements have been made to verify the use of 2D numerical device simulations for the analysis. It is found that the input capacitance, Cgg, of the LDMOS transistor working under power match conditions is a strongly non-linear function of gate voltage Vg but with an almost linear initial increase in Cgg. The voltage dependence of Cgg is found to mainly affect higher order IMD products in class-A operation. Transient simulations however show that Cgg seriously contributes to the onset of AM–PM conversion well below the 1 dB compression point.
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| 39. |
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| 40. |
- Bengtsson, Olof, et al.
(författare)
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Optimization of High-Voltage RF Power SiGe Transistors for Cellular Applications
- 1999
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Ingår i: High Power Microwave Electronics. - 5778202709
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Konferensbidrag (refereegranskat)abstract
- The base profile design for high-voltage RF power silicon transistors with epitaxial SiGe base was studied using 2-D process and device simulations. The addition of Ge in the base makes thin base widths with very high base doping possible. This gives rise to a higher maximum oscillation frequency thus improving the critical power gain for these devices
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| 41. |
- Bengtsson, Olof, et al.
(författare)
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Small Signal and Power Evaluation of Novel BiCMOS Compatible, Short Channel LDMOS Technology
- 2003
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Ingår i: IEEE transactions on microwave theory and techniques. - 0018-9480 .- 1557-9670. ; 51:3, s. 1052-1056
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Tidskriftsartikel (refereegranskat)abstract
- We describe a very short-channel 0.15-mum LDMOS transistor with a breakdown voltage of up to 60 V, manufactured in a standard 0.35-mum BiCMOS process. At 1900 MHz and a 12-V supply voltage, the 0.4-mm-gatewidth device with shortest drain drift region gives 100-mW output power P-1 dB at a drain efficiency of 43%. It has a transducer power gain of over 20 dB. The maximum current gain cutoff frequency f(T) is 15 GHz, and the maximum available gain cutoff frequency f(MAX) is 38 GHz. We show the dependence of f(T), an f(MAX) of gate and drain bias for transistors with different-drain drift region length. The LDMOS process module does not affect the performance or the models of other devices. We present for the first time a simple way to create high-voltage high-performance LDMOS transistors for an RF power amplifier use even in a very downscaled silicon technology.
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| 42. |
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| 43. |
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| 44. |
- Bengtsson, Stefan, 1961, et al.
(författare)
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Characterisation of interface electron state distributions at directly bonded silicon/silicon interfaces
- 1990
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Ingår i: ESSDERC 90. 20th European Solid State Device Research Conference. ; , s. 1-
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Konferensbidrag (refereegranskat)abstract
- Measurement methods for characterizing the electrical properties of directly bonded Si/Si n/n-type or p/p-type interfaces are presented. The density of interface states in the bandgap of the semiconductor and the density of interface charges at the bonded interface are determined from measurements of current and capacitance vs. applied voltage
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| 45. |
- Bengtsson, Stefan, 1961, et al.
(författare)
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Charge densities at silicon interfaces prepared by wafer bonding
- 1990
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Ingår i: 1990 IEEE SOS/SOI Technology Conference.. ; , s. 77-
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Tidskriftsartikel (refereegranskat)abstract
- It is found that Si/Si and Si/SiO2 interfaces exhibit different interface charge properties when bonded at comparable temperatures and surface treatments. Thermally grown oxides were bonded to bare silicon surfaces and the bonded Si/SiO2 interface was investigated on MOS-structures by the C-V technique. Interfaces prepared at temperatures in the range 900-1100°c exhibited U-shaped interface state densities. Si/Si samples were prepared using a hydrophilizing surface treatment before wafer bonding. At the same annealing temperatures, the interface state densities of the bonded Si/Si interfaces were in the range 1011-1013 cm-2 eV-1. Si/Si interfaces are found to be very sensitive to prebond chemical treatment, while Si/SiO2 interfaces are not. Native oxides at bonded silicon interfaces have a more pronounced influence on Si/Si interfaces than on Si/SiO2 interfaces
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| 46. |
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| 47. |
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| 48. |
- Bengtsson, Staffan
(författare)
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Herders hieroglyf : Om den okända metoden i hans författarskap
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The dissertation addresses the problem if Johann Gottfried Herder had a method when he composed his works. The overwhelming majority of scholars says no and describes him as a restless author who reworks manuscripts; digressing and repeating himself; leaning on others rather than writing a monographic work on his own – someone who does not write complete and structured works, and therefore is seen as a precursor in history rather than occupying a place in it.This thesis claim that Herder’s work is structured in minutest detail, and demonstrates how Herder uses typographic marks to guide the reader through his dialectical text-structure.Herder uses a four-step dialectic. It starts from a center-position with a confused issue, which is analyzed and put together again. The second position analyses one aspect of the issue at hand in one direction and the third in an opposite direction. These consecutive steps in the reading process could be regarded as simultaneous parts of an image. The fourth fuses and simultaneously changes them into a new center-position, which presents the issue in a new form.This four-step movemen can be repeated in a series of such movements. The fourth position turns then into a new starting-point. The issue is further analyzed. Positions two and three continues the perspective of foregoing two and three. The fourth position brings together.The first part gives a representive overview of the research on Herder. Special attention is givien to editions, and how they leave out typographic marks important for understanding the text’s structure. Research is characterized as a turning away from Herder’s works, either to handwriting or to a tradition which Herder only partly belongs to. Herder is instead situated in aesthetics – his “human philosophy”. The second part analyzes The Oldest Document of the human race.
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| 49. |
- Bengtsson, Stefan, 1961, et al.
(författare)
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IC process compatible preparation of silicon interfaces using the silicon-to-silicon direct bonding method
- 1989
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Ingår i: ESSDERC '89. 19th European Solid State Devices Research Conference. ; , s. 353-
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Konferensbidrag (refereegranskat)abstract
- Silicon/silicon interfaces were prepared by wafer bonding using the silicon-to-silicon direct bonding method. Silicon/silicon interfaces (n/n-type) with excellent electric properties were prepared, by using hydrophobic wafer surfaces, at temperatures in the range of 700°C to 1000°C. The influence of the bonded interface on device characteristics of bonded p+n junctions prepared at low temperatures was seen as n-factors larger than 2 at forward bias. A correlation between n-factors and the density of states in the bandgap was found. In hydrophilic samples, the density of voids at the bonded interface was determined mainly in the contacting of the wafer surfaces at room temperature. Compared to hydrophilic samples, hydrophobic samples were held together at a smaller fraction of the area before heat treatment. After the heat treatments, no difference in the density of voids was found
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| 50. |
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