| 1. |
- Engelmark, O., et al.
(författare)
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Ecological effects and management aspects of an exotic tree species : the case of lodgepole pine in Sweden
- 2001
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Ingår i: Forest Ecology and Management. - 0378-1127 .- 1872-7042. ; 141:02-jan, s. 3-13
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Tidskriftsartikel (refereegranskat)abstract
- The North American tree Pinus contorta var, latifolia was experimentally introduced in Sweden already in the 1920s, and has been used in Swedish forestry on a large scale since the 1970s. These plantations now cover 565,000 ha, mainly in the northern area. In this paper we summarize and discuss existing ecological knowledge of this species introduction. With regard to longterm sustainability we suggest management means to minimize harmful effects of the introduction on ecosystems. These include aspects of self dispersal, pests, ecosystem and landscape structures, and also ecological processes and biodiversity. We also focus on observed and possible interactions in the ecosystems. As Pinus contorta seeds are disseminated and trees regenerated outside initial plantations, this may have future bearings on biodiversity. We suggest a strategy which takes account of the uncertainty in predicting future ecological effects. The strategy includes areal restrictions and zones without Pinus contorta, but also to set up a monitoring program. Observations of adverse effects from the plantations would then give the possibility to adjust P. contorta management.
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| 2. |
- Jansik, B., et al.
(författare)
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Relativistic effects on linear and non-linear polarizabilities of the furan homologues
- 2003
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Ingår i: Journal of Molecular Structure. - 0166-1280. ; 633:2-3, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- First principles calculations including relativistic effects are carried out for dipole moments, polarizabilities, first- and second-order hyperpolarizabilities for the series of furan homologues XC4H 4, X = O, S, Se, Te, at three different levels of theory, time-dependent Dirac-Hartree-Fock (DHF), time-dependent Hartree-Fock with a Douglas-Kroll transformed one-component Hamiltonian, and time-dependent Hartree-Fock using effective-core potentials. By comparison with the corresponding non-relativistic results, the influence of relativistic effects on the properties as well as the accuracy of previously reported calculations on these molecules using effective-core potentials for selenium and tellurium can be addressed. The obtained results indicate that relativistic effects can be described with comparable accuracy at all three employed levels, and that non-scalar effects, which are explicitly treated only at the time-dependent DHF level, are of minor importance. Frequency dispersion and relativity are found to be additive at the single-determinant level. We find that relativistic effects cannot make up for the earlier identified mismatch between theory and experiment for the non-linear polarizabilities of the heavier homologues. A Bishop-Kirtman analysis of vibrational effects indicates that the same can be said about these. © 2003 Elsevier B.V. All rights reserved.
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| 3. |
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| 4. |
- Agren, P., et al.
(författare)
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Hysteretic current-voltage characteristics and Coulomb blockade in 1D-arrays of Josephson junctions
- 2000
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 280:04-jan, s. 414-415
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Tidskriftsartikel (refereegranskat)abstract
- The IV characteristics (IVC) of 1D-arrays of small capacitance Josephson junctions with E-C similar to E-J have been measured. The IVC show Coulomb blockade of Cooper pair tunneling and exhibit a pronounced hysteresis which appears to be dual to the well-known resistively shunted junction behavior of ordinary Josephson junctions. A dual serially resistive junction model is used to qualitatively explain the measured data.
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| 5. |
- Agren, P., et al.
(författare)
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Kinetic inductance and Coulomb blockade in one dimensional Josephson junction arrays
- 2001
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Ingår i: Journal of Low Temperature Physics. - 0022-2291 .- 1573-7357. ; 124:02-jan, s. 291-304
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Tidskriftsartikel (refereegranskat)abstract
- One dimensional Josephson junction arrays have been fabricated and current-voltage characteristics (IVC) have been measured at cryogenic temperatures. The arrays were fabricated in a SQUID-geometry which allowed an in. situ tuning of thc Josephson energy by application of a magnetic field. The IVC of thc arrays shows a clear Coulomb blockade state. In the Coulomb blockade regime the IVC are hysteretic, The array is modeled using a Serial resistive-inductive-junction model which is able to qualitatively explain the IVC. In this model an inductance of the order of 0.1-10 mH per Junction is needed to account for the hysteresis. Kinetic inductance. stemming from the inertia of the Cooper pairs. gives the correct order of magnitude. The problem of self-heating is also discussed as an alternative explanation of the hysteresis.
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| 6. |
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| 7. |
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| 8. |
- Bagesund, M, et al.
(författare)
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Correlation between quantitative salivary gland scintigraphy and salivary secretion rates in children and young adults treated for hematological, malignant and metabolic diseases
- 2000
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Ingår i: Dento-Maxillo-Facial Radiology. - 0250-832X .- 1476-542X. ; 29:5, s. 264-271
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To study the correlation between whole salivary secretion rates and different variables from the radionuclide time-activity curve and to determine a reliable region for background correction in salivary gland scintigraphy. Methods: Salivary gland scintigraphy (SGS) was performed before bone marrow transplantation or more than 4 years later in 23 patients aged 13.5 (s.d. 4.9) years. Unstimulated and stimulated whole salivary secretion rates were measured before SGS. Six different methods for background correction were evaluated. Results: The unstimulated secretion rate was significantly correlated (P<0.05) with the percentage stimulated secretion (S) and reaccumulation-slope (RS) after stimulation. The stimulated secretion rate was significantly correlated with RS, S and down-slope (DS). The temporal region above the parotid glands and the area above the thyroid gland was used for subtraction of background radiation for the parotid and submandibular glands respectively showed a strong correlation between repeated measurements of the variables analysed. The mean maximum uptake was 0.73-1.34% of total dose injected. Conclusions: The salivary scintigraphic variables which correlated more strongly with salivary secretion rates were RS, S and DS. The temporal region above the parotid gland and the area above the thyroid gland can be used reliably for correction background radiation in the analysis of the time-activity curve in SGS of the parotid and submandibular glands respectively.
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| 9. |
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| 10. |
- Bagesund, M, et al.
(författare)
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Scintigraphic study of the major salivary glands in pediatric bone marrow transplant recipients
- 2000
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Ingår i: Bone Marrow Transplantation. - 0268-3369 .- 1476-5365. ; 26:7, s. 775-779
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Tidskriftsartikel (refereegranskat)abstract
- Total body irradiation (TBI) at bone marrow transplantation (BMT) is shown to cause salivary gland dysfunction in children. The aim of the investigation was to study the function of major salivary glands in long-term surviving children following treatment with TBI, using salivary gland scintigraphy (SGS), Thirteen patients (seven male, six female), who had received TBI before the age of 13 years and survived more than 4 years, participated in the study. A reference group of 10 patients (nine male, one female) was examined shortly before they were to undergo BMT, The mean age was 14.1 +/- 4.1 years in the TBI-treated group and 12.8 +/- 5.9 years in the reference group, Unstimulated and stimulated whole salivary secretion rates were measured for 15 and 5 min, respectively, before SGS was performed, The percentage of stimulated secretion was 44.7 +/- 18.1% in the TBI-treated group compared to 58.4 +/- 13.0% in the reference group (P = 0.0438). Slower reaccumulation after excretion was found in the TBI-treated patients compared to the reference group (P = 0.0300). The function of the major salivary glands in long-term survivors treated with TBI at BMT before the age of 13 years was found to be diminished, as shown by the reduced trapping rate and reduced emptying capacity, compared to prior to BMT.
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| 11. |
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| 12. |
- Hallmans, Göran, et al.
(författare)
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Cardiovascular disease and diabetes in the Northern Sweden Health and Disease Study Cohort : evaluation of risk factors and their interactions.
- 2003
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Ingår i: Scandinavian Journal of Public Health. Supplement Links. - : SAGE Publications. - 1403-4956 .- 1403-4948 .- 1651-1905. ; 61, s. 18-24
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is, first, to describe the organization, sampling procedures, availability of samples/database, ethical considerations, and quality control program of the Northern Sweden Health and Disease Study Cohort. Secondly, some examples are given of studies on cardiovascular disease and diabetes with a focus on the biomarker programme. The cohort has been positioned as a national and international resource for scientific research.
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| 13. |
- Haviland, David B., et al.
(författare)
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Quantum phase transition in one-dimensional Josephson junction arrays
- 2001
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Ingår i: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 352:04-jan, s. 55-60
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Tidskriftsartikel (refereegranskat)abstract
- We describe experiments on one-dimensional arrays of small capacitance Josephson junctions which show how the Coulomb blockade of Cooper pair tunneling is influenced by changing the Josephson coupling energy in situ with an externally applied magnetic flux. We show how the zero bias resistance of the array is affected by the length of the array, and we use the length scaling of this resistance to infer that a quantum phase transition occurs as the Josephson coupling energy is changed. The data are qualitatively analyzed in terms of a theoretical model of the quantum phase transition which uses a mapping to the two-dimensional XY model.
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| 14. |
- Haviland, David B., et al.
(författare)
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Superconducting and insulating behavior in one-dimensional Josephson junction arrays
- 2000
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Ingår i: Journal of Low Temperature Physics. - 0022-2291 .- 1573-7357. ; 118:06-maj, s. 733-749
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Tidskriftsartikel (refereegranskat)abstract
- Experiments on one-dimensional small capacitance Josephson Junction arrays are described. The arrays have a junction capacitance that is much larger than the stray capacitance of the electrodes, which we argue is important for observation of Coulomb blockade. The Josephson energy can be tuned in situ and an evolution from Josephson-like to Coulomb blockade behavior is observed. This evolution can be described as a superconducting to insulating, quantum phase transition. In the Coulomb blockade state, hysteretic current-voltage characteristics are described by a dynamic model which is dual to the resistively shunted junction model of classical Josephson junctions.
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| 15. |
- Henriksson, K M, et al.
(författare)
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Development of hypertension over 6 years in a birth cohort of young middle-aged men: the Cardiovascular Risk Factor Study in southern Sweden (CRISS).
- 2002
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Ingår i: Journal of Internal Medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 252:1, s. 21-26
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To explore the development of hypertension (HT) in a cohort of young middle-aged men. DESIGN: Prospective birth-cohort study of men surveyed over 6 years. SETTING: Helsingborg County Hospital, Sweden, 1990-97. SUBJECTS: A total of 628 men born in 1953-54, all surveyed at 37, 40 and 43 years of age. MAIN OUTCOME MEASURES: Systolic blood pressure (SBP), diastolic blood pressure (DBP), S-cholesterol, body mass index (BMI), alcohol consumption, ethnicity. HT was defined as SBP > or = 140 mmHg and/or DBP > or = 90 mmHg, or ongoing treatment. Using SBP < 130 mmHg and DBP < 85 mmHg as reference, the odds of conversion to HT in men with high normal blood pressure (BP) (SBP 130-139 mmHg and DBP 85-89 mmHg) was investigated. RESULTS: At age 37, 243 men (39%) had reference BP, 167 (26%) had high normal BP and 218 (35%) were hypertensive. Corresponding numbers at age 40 were 265 (42%), 166 (27%) and 197 (31%); and at age 43, 180 (29%), 142 (22%) and 306 (49%), respectively. High normal BP at baseline was associated with the development of HT both at age 40 (odds ratio (OR)=2.45 confidence interval (CI): 1.42-4.22) and at age 43 (OR=2.46, CI: 1.59-3.80), independent of other cardiovascular disease risk factors and ethnicity. The progression to HT was predicted also by S-cholesterol, alcohol consumption, BMI and weight gain. CONCLUSIONS: Over a short-term period, a substantial proportion of young middle-aged men with high normal BP develop HT with overweight and alcohol consumption as important determinants. These findings have implications for the prevention, screening and medical care of HT in this target population.
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| 16. |
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| 17. |
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| 18. |
- Salek, P, et al.
(författare)
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Dynamical suppression of atomic peaks in resonant dissociative photoemission
- 2001
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Ingår i: CHEMICAL PHYSICS LETTERS. - : ELSEVIER SCIENCE BV. - 0009-2614. ; 343:3-4, s. 332-338 Language: English
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Tidskriftsartikel (refereegranskat)abstract
- Resonant excitation to the F1s-sigma* dissociative state in hydrogen fluoride gives a photoelectron spectrum where the spectator part contains strong atomic lines but a participator part where such lines are lacking. We demonstrate that this contrasting b
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| 19. |
- Schollmann, V., et al.
(författare)
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Sample and hold strategy for quantum measurements of Josephson charge qubits
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 65:2
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Tidskriftsartikel (refereegranskat)abstract
- We present a design for a charge qubit, and an associated quantum sample and hold measurement scheme. Using arrays of superconducting. islands, connected by tunable tunnel junctions, we can sample the charge states by turning off the Josephson coupling, and then hold a Cooper pair on an island for a very long time. This allows for a slow readout using a conventional weakly coupled low-frequency single-electron transistor.
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| 20. |
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| 21. |
- Wang, Q., et al.
(författare)
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Wide-aperture GaAs/AlGaAs multiple quantum well electro-optic modulators
- 2002
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Ingår i: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 4947, s. 59-67
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present design and fabrication methods for surface normal monolithic amplitude modulators with an aperture up to 14 × 14 mm2, a contrast ratio of 6:1 and for low driving voltages (=8 V). The modulators consist of undoped GaAs/AlGaAs quantum wells embedded in a Fabry-Perot (FP) resonance cavity grown by MOVPE. To improve the device performance the FP cavity, the period and thickness of the quantum well and doping concentration were optimised. Also, the dimension of the modulator were varied from 0.5 × 0.5 to 14 × 14 mm2. The results show that the yield of the modulators increases significantly when decreasing the size of the modulators. To remedy the low yield issue for wide aperture modulator, a pixelated approach was used to divide the mono pixel in a monolithic modulator into several pixels, for example from 4 to 48. The modulation speed of the modulators with different dimensions was characterised by electro-optic (EO) response measurements. The temporal optical response of the large modulators was satisfactory up to the order of MHz modulation frequency where the RC constant limited the performance. A few of the modulators with wide apertures are to be assembled into an optical link system for free-space communication.
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