857 research outputs found
A search for solar dark matter with the IceCube neutrino telescope
No full textDark matter particles in the form of supersymmetric Weakly Interacting Massive Particles (WIMPs) could accumulate in the centre of the Sun because of gravitational trapping. Pair-wise annihilations of WIMPs could create standard model particles out of which neutrinos could reach the Earth. Data from the IceCube 22-string neutrino telescope have been searched for signals from dark matter annihilations in the Sun. Highly sophisticated analysis methods have been developed to discern signal neutrinos from the severe background of atmospheric particle showers. No signal has been found in a dataset of 104 days livetime taken in 2007, and an upper limit has been placed on the muon flux in the South Pole ice induced by neutrinos from the Sun, reaching down to 330 km-2y-1. The flux limit has been converted into an upper limit on the neutralino scattering cross-section, which reaches down to 2.8*10-40 cm2 for spin-dependent interactions.Four articles are appended to the thesis:I. G. Wikström for the IceCube collaboration, Proc. of the 30th ICRC,arXiv/0711.0353 [astro-ph] (2007) 135.II. A. Gross, C. Ha, C. Rott, M. Tluczykont, E. Resconi, T. DeYoung and G. Wikström for the IceCube Collaboration, Proc. of the 30th ICRC,arXiv/0711.0353 [astro-ph] (2007) 11.III. G. Wikström and J. Edsjö, JCAP 04 (2009) 009.IV. R. Abbasi et al. (IceCube collaboration), accepted for publication in Phys. Rev. Lett., arXiv/0902.2460v3 [astro-ph.CO] (2009).IceCub
On shoplifting and tax fraud: An action-theoretic analysis of crime
No full textThe article evaluates different theories of action in the area of crime research. A narrow version of rational choice theory assumes actors to choose in an instrumental, outcome-oriented way. It hypothesises that individuals weight the costs and benefits of criminal acts with subjective probabilities. In contrast, a wide version of the theory allows individuals to derive utility directly from choosing certain actions. Previous studies either do not directly test these theories or yield inconsistent results. We show that a meaningful test of these rival rational choice explanations can only be conducted if a broader view is adopted that takes into account the interplay of moral norms and instrumental incentives. Such a view can be derived from the Model of Frame Selection (Kroneberg 2005) and the Situational Action Theory of Crime Causation (Wikström 2004). Based on these theories, we analyze the willingness to engage in shoplifting and tax fraud in a sample of 2,130 adults from Dresden, Germany. In line with our theoretical expectations, we find that only respondents who do not feel bound by moral norms consider instrumental incentives. Where norms have been strongly internalised and in the absence of neutralisation techniques which legitimise norm-breaking, instrumental incentives are irrelevant.
Developmental and stress induced changes in peptide and catecholamine content of the paraaortic paraganglia
No full textThe paraaortic body (PAB) is the largest extra-adrenal paraganglion and during the perinatal period it contains a substantial amount of catecholamines (CAs). The PAB also contain peptides, whose function in the PAB is not clear. The main object of this thesis was to examine peptides in the PAB, to describe their perinatal development and response to different stimuli. The effect of tumor transition on the expression of peptides was also studied. Enkephalin-(ENK), galanin-(GAL), and neuropeptide Y-(NPY) like immunoreactivities (LI) were demonstrated in paraganglion cells as well as in adrenal medullary cells of fetal or newborn animals of three species; i.e. the rabbit, guinea-pig and pig. However, NPY-LI was not detected in these cells of the pig. In addition, coexistence of NPY/GAL, NPY/ENK, and GAL/ENK was observed within the paraganglion cells of the guinea pig. The coexistence of these peptides was also demonstrated on the subcellular level, since both GAL- and NPY-LI as well as noradrenaline (NA) and adrenaline were present in the chromaffin granule fraction after ultracentrifugation of adrenal gland homogenate on a sucrose density gradient. This strongly suggests that both peptides are stored in chromaffin granules together with CAs. A higher number of peptides is expressed in paraganglion cells, which have undergone tumor transition. In a human paraganglioma, immunoreactivities to ENK, dynorphin, somatostatin, and calbindin were the most frequently expressed peptides, whereas immunoreactivities, to GAL, NPY, and cholecystokinin were less frequent.The PAB is prominent in the fetal and newborn rabbit, why this species was chosen for the subsequent developmental studies. During the perinatal period, the highest content of GAL- and NPY-LI in the rabbit PAB was found at birth and after birth both decreased. In contrast, the content of ENK-LI showed a progressive increase with age, as did the content of the CAs. This suggests that the expression of these peptides is regulated differently. In the adrenal gland, there was a progressive increase with age in the content of all peptides as well as of the CAs. At birth, the PAB content of all these peptides was higher than in the adrenal glands. This is the first report describing the perinatal development of GAL- and NPY-LI in paraganglia and, for GAL-LI, also in the adrenal gland. The PAB content of the peptides did not change in response to asphyxia, insulin-induced hypoglycemia or reserpine, with the exception of an increased content of ENK-LI by 60 minutes of asphyxia. Also in the adrenal gland, ENK-LI tended to increase after asphyxia, whereas the adrenaline content was reduced. The only peptide for which its adrenal content was reduced by insulin-induced hypoglycemia was ENK-LI. The reduction of ENK-LI was strikingly parallel to the reduction of the CAs and was significant at all times between 1.5 and 4 hours after insulin administration (20 U/kg). Reserpine (15 mg/kg) reduced the CA content in both the PAB and adrenal glands three hours after administration, whereas no change in peptide content was observed.The present results demonstrates that there is a relatively homogenous expression of peptides in the three species studied, with the exception for NPY-LI in the pig, and that these peptides can occur in the same chromaffin cells, where they can be localized within the same chromaffin granule as the CAs. During the perinatal period they appear to be regulated differently in the PAB, where the highest amounts of GAL- and NPY-LI are found at birth, whereas the PAB content of ENK-LI increases postnatally. The possible role of these peptides in the PAB has not been established, since the PAB content of these peptides was unchanged in response to all stimuli used.List of scientific papersI. Fried G, Meister B, Wikström M, Terenius L, Goldstein M. (1989). Galanin-, neuropeptide Y- and enkephalin-like immunoreactivities in catecholamine-storing paraganglia of the fetal guinea pig and newborn pig. Cell Tissue Res. 255(3):495-504. https://pubmed.ncbi.nlm.nih.gov/2468416II. Fried G, Wikström LM, Höög A, Arver S, Cedermark B, Hamberger B, Grimelius L, Meister B (1994). Multiple neuropeptide immunoreactivities in a renin-producing human paraganglioma. Cancer. 74(1):142-51. https://pubmed.ncbi.nlm.nih.gov/7911735III. Fried G, Wikström LM, Franck J, Rökaeus Å (1991). Galanin and neuropeptide Y in chromaffin granules from the guinea-pig. Acta Physiol Scand. 142(4):487-93. https://pubmed.ncbi.nlm.nih.gov/1719746IV. Wikström LM, Rökaeus Å, Fried G (1993). Perinatal development of galanin-like immunoreactivity in chromaffin tissues of the rabbit. Regul Pept. 44(3):297-303. https://pubmed.ncbi.nlm.nih.gov/7683437V. Wikström LM, Meister B, Franck J, Fried G (1996). Changes in enkephalin and neuropeptide Y-like immunoreactivity in rabbit chromaffin tissues during perinatal development. Regul Pept. 61(1):37-44. https://pubmed.ncbi.nlm.nih.gov/8701025VI. Wikström LM, Rökaeus Å, Fried G. (1998). Effects of acute stress on the contents of catecholamines and neuropeptides in chromaffin tissues of the newborn rabbit. Regul Pept. 78(1-3):125-31. https://pubmed.ncbi.nlm.nih.gov/9879755</p
Pleurota dalilae Tabell & Wikström & Mutanen & Bruckner & Sihvonen 2021, sp. nov.
No full textPleurota dalilae Tabell, sp. nov. Barcode Index Number:BOLD:ADB1135 Table 1, Figs. 21–22, 42, 59, 65, 66 Type material. Holotype ♀ (GP 5914 J. Tabell, DNA sample 26143 Lepid Phyl): Tunisia, 2 km E El Kef, N36.1722 E8.7327, 8.V.2018, J. Tabell leg. (coll. MZH), BOLD sample ID: MM26143, http://id.luomus.fi/GBT. 4 Paratypes: 3 ♂ (GP 5920 J. Tabell, DNA sample 26142 Lepid Phyl; DNA sample 26258 Lepid Phyl), same collecting data as holotype (coll. TAB); 4 ♂ (DNA sample 24829 Lepid. Phyl; DNA sample 24828 Lepid Phyl [barcoding failed]; DNA sample 24830 Lepid Phyl [barcoding failed]; DNA sample 24831 Lepid Phyl [barcoding failed]), Tunisia, Atlas Mts, 40 km SE Le Kef, near El Ksour village, 2.V.2000, K. Nupponen leg. (colls. NUP and TAB); 21 ♂ (GP 5910 J. Tabell, DNA sample 26259 Lepid Phyl; DNA sample 26260 Lepid Phyl; GP 5917 J. Tabell, DNA sample 26262 Lepid Phyl), Tunisia, 13.5 km ESE Maktar, 810 m, N35.8022 E9.3386, 7.V.2018, J. Tabell leg. (coll. TAB). Diagnosis. P. dalilae is externally similar to P. bicostella and P. lepigrei, but it is smaller, and the fringes on forewing are darker. In the male genitalia, the posterior lobe of juxta is longer and narrower than in bicostella, but shorter than in lepigrei. In the female genitalia, the shape of segment 8 (subquadrate in dalilae, quadrate in bicostella, longitudinally rectangular in lepigrei), the shape of antrum (anteriorly expanded in dalilae, tapered in bicostella, parallel-sided in lepigrei) and the size of posterior signa, are distinguishing characters. Molecular data. Seven specimens of dalilae were sequenced successfully, resulting in 658 (n=1), 655 (n=1), 654 (n=3), 622 (n=1) and 621 (n=1) bp barcode sequences. The nearest neighbour to dalilae is lepigrei, with a 2.99 % divergence. The barcodes of dalilae exhibit 0.65 % intraspecific variation. Description. Adult. Wingspan 17.8–20.8 mm. Labial palpus off-white, ventrally dark brown, 6.4 x as long as diameter of eye (1 st and 2 nd palpomeres), 3 rd palpomere 0.32 x length of 1 st and 2 nd palpomeres.Antenna brown. Head off-white, thorax and tegula off-white, mixed with pale brown. Forewing white, dispersed with pale ochre, pale grey and pale brown scales, discal spot distinct, discocellular spot small, plical streak indistinct, fringe line distinct; costal line white, moderately broad, from near base to 0.8; subcostal line brown, slightly expanded towards apex. Fringe mixed with white and pale grey. Hindwing pale grey, fringe pale grey, apically white. Abdomen pale grey, slightly lustrous, each segment with a transverse row of ochre scales. Male genitalia. Uncus bell-shaped from ventral view, as long as gnathos, covered with several bristles of different size, apex with long narrow stout protuberance. Gnathos funnel-shaped from ventral view, evenly tapered towards apex, apical third surfaced with scobination, apex stout. Valva slightly upwardly oblique from ventral view, ventral margin medially slightly bulged, costa horizontal, slightly bulged medially; cucullus thimble-shaped; sacculus moderately broad, covered with several bristles; valval lobe well delineated, crescent-shaped, surfaced by several nodules with bristles. Juxta tuning-fork-shaped; posterior lobe exceeding the base of uncus. Phallus slightly arched, parallel-sided, with one plate-shaped weakly sclerotized cornutus and a patch of small spines. Female genitalia. Papilla analis elongate, narrow, densely covered with bristles of different size. Apophysis posterioris 2.9 x as long as papilla analis and 1.5 x as long as apophysis anterioris, which is 1.3 x as long as segment 8. Segment 8 subquadrate, dorsolaterally sclerotized by a narrow band, proximal margin evenly convex, broadly sclerotized, caudal margin slightly concave, lined with several long bristles; ventral longitudinal sclerotization clubshaped. Antrum as long as segment 8, anteriorly expanded, membranous, with two small sclerotized plates. Ductus bursae short and broad. Corpus bursae ovoid, large, with one wide arched signum bearing two narrow and long protuberances, and two leaf-shaped posterior signa with broad base and narrow spine. Biology. Unknown. The specimens collected by the first author were netted in Pinus forests, lower vegetation dominated by Cytisus sp. (Fabaceae) in El Kef and Salvia rosmarinus (Lamiaceae) near Maktar. Etymology. The species is named in honour of Tunisian scientist Dr. Dalila Haouas. Distribution. Tunisia, known from two localities in Kef Governorate near the Algerian border. Results. The series from near Maktar was collected with P. illucidella.Published as part of Tabell, Jukka, Wikström, Bo, Mutanen, Marko, Bruckner, Harald & Sihvonen, Pasi, 2021, Subspecies of Pleurota bicostella (Clerck, 1759) revisited and descriptions of nine new species in the P. bicostella species group (Lepidoptera: Gelechioidea Oecophoridae: Pleurotinae), pp. 451-486 in Zootaxa 4941 (4) on pages 469-470, DOI: 10.11646/zootaxa.4941.4.1, http://zenodo.org/record/459550
Water-gated mechanism of proton translocation by cytochrome c oxidase
No full textAbstractCytochrome c oxidase is essential for aerobic life as a membrane-bound energy transducer. O2 reduction at the haem a3–CuB centre consumes electrons transferred via haem a from cytochrome c outside the membrane. Protons are taken up from the inside, both to form water and to be pumped across the membrane (M.K.F. Wikström, Nature 266 (1977) 271 [1]; M. Wikström, K. Krab, M. Saraste, Cytochrome Oxidase, A Synthesis, Academic Press, London, 1981 [2]). The resulting electrochemical proton gradient drives ATP synthesis (P. Mitchell, Chemiosmotic Coupling in Oxidative and Photosynthetic Phosphorylation, Glynn Research, Bodmin, UK, 1966 [3]). Here we present a molecular mechanism for proton pumping coupled to oxygen reduction that is based on the unique properties of water in hydrophobic cavities. An array of water molecules conducts protons from a conserved glutamic acid, either to the Δ-propionate of haem a3 (pumping), or to haem a3–CuB (water formation). Switching between these pathways is controlled by the redox-state-dependent electric field between haem a and haem a3–CuB, which determines the water–dipole orientation, and therefore the proton transfer direction. Proton transfer via the propionate provides a gate to O2 reduction. This pumping mechanism explains the unique arrangement of the metal cofactors in the structure. It is consistent with the large body of biochemical data, and is shown to be plausible by molecular dynamics simulations
University education and income – does prior achievement matter?
No full textThe purpose of this study is to find out if the income premium from university entrance differs with respect to prior achievement as measured by previous grades. Using income at the age of 28 to 30, we analyze if high-achievers have larger income premiums from entering university than low-achievers in a sample of Swedish upper secondary school students. We find that income differences generally are positive, albeit larger for females than for males. It is also found that the income premium is larger for high-achievers than for low-achievers. However, especially for males, the income premium rises only marginally with prior achievement for a large part of the grade distribution, indicating that there are only small differences in the returns to university entrance for a majority of upper secondary school graduates.Premium; Predictive validity; Upper secondary GPA; Achievement; University entrance
E-exchange and the Boundary between Households and Organizations
No full textThe new information and communication technology, ICT, induces households to take over tasks from firms and government agencies, using tools and systems provided by these very same organizations. The result is often joint production activities. We argue that the importance of ICT for the exchange process between households and organizations is underestimated by only considering the consequences for the last stage of the process, i.e., the final purchase of goods and services. Our analysis of household behavior utilizes a modified version of Gary Becker’s model of the household as a combined producer-consumer.internet information, e-exchange, household production, co-production, household power, exit/voice
Treatment outcomes of regenerative endodontics and apexification of traumatized immature necrotic permanent incisors [Elektronisk resurs]
No full textIntroduction: Presently, calcium hydroxide (CH) apexification and mineral trioxide aggregate (MTA) apexification are the available treatments for traumatized immature necrotic teeth. Although these treatments have been available for many years, few studies have assessed these techniques for long- term survival of teeth. Recently, a new treatment modality has emerged - regenerative endodontic treatment (RET). However, RET's clinical, radiographic, and disinfection protocols need to be evaluated. Aims: This thesis investigates the clinical, radiographical, and microbiological outcomes of regenerative endodontic treatment. In addition, this thesis investigates the long-term survival of traumatized immature necrotic teeth after the use of apexification and identifies the risk factors for premature tooth loss. Materials and methods: This thesis includes a systematic literature review (Study I), an observational prospective cohort design (Study II), a randomized clinical trial (Study III), and a retrospective longitudinal observational cohort design (Study IV). In Study I, five scientific databases were screened (PubMed, Web of Science, Cochrane Library, Ovid/Medline, and Embase) for intervention studies on RET and/or apexification of traumatized immature necrotic teeth. Only peer- reviewed studies with a study size of at least 20 cases with a follow-up of 24 months were included. Eligibility assessment was blinded and performed independently. Subgroup analyses were performed on three outcomes: survival, success, and continued root development. In Study II, RET was performed on 75 traumatized necrotic immature incisors. The radiographic outcome measures were continued root formation (width and length), root resorption, apex closure, periapical index, and root development stage. The clinical outcome measures were percussion pain, palpation pain, pathological tooth mobility, swelling, sinus tract, ankylosis, crown discolouration, and subjective pain. Treatment outcomes were categorized as a success or failure based on the clinical and radiographic outcome measures. In Study III, microbiological assessment was based on root canal samples from 41 traumatized immature necrotic teeth treated with RET where two different root canal dressing were used in a randomized order (CH and CHD). Analysis of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed at three timepoints - before root canal dressing (S2); after debridement (S); and after root canal dressing (S5). In Study IV, records of 2400 children and adolescents were screened for presence of TDI to immature incisors where endodontic treatment with the two apexification techniques was performed between January 2003 and December 2022. These incisors were compared to a control group of mature teeth treated with conventional endodontic techniques. The following variables were studied: age, sex, apexification technique, presence of luxation and hard tissue injuries, preoperative root development stage (RDS), preoperative and postoperative periapical index (PAI), when tooth loss occurred, and overall survival time in years. Results: Seven studies with heterogenous designs were included in the final synthesis. The included articles in Study I revealed that both regenerative and apexification techniques had equal rates of success and survival and proved to be effective in the treatment of immature necrotic permanent teeth. Regenerative endodontic techniques appeared to be superior to apexification techniques in terms of stimulation of root maturation - i.e., root wall thickening and root lengthening. Study II revealed that RET was successful in 60% of the cases. When successful, RET presented meaningful outcomes, with a resolution of periapical infection, increased root length and width, and apex closure. Two predictive variables for continued root maturation were identified - preoperative root development stage and preoperative dentine wall thickness. The failed cases were related to lack of bleeding and persistent infections. Study III revealed that the primary microflora were more diverse in successful cases than in failed cases. Decreases in bacterial loads and diversity/sample occurred between S2 and S3, although new increases were seen at S5 in the CHD subgroup (successful and failed) and load/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species were associated with the outcomes with no statistical differences between the disinfection efficacies. Study IV showed that the median survival time was up to 10 years for CH apexification, 16.1 years for MTA apexification, 15.5 years for luxation injuries other than intrusions and avulsions, 12.5 years for intrusions, and 6.8 years for avulsions. The variables with significant negative impact on tooth survival were CH apexification, avulsion, and postoperative PAI of 3-5. No significant relationships were found for the variables MTA apexification, concussion, subluxation, lateral luxation, extrusion, intrusion, hard tissue injuries, preoperative RDS, preoperative PAI scores and postoperative PAI scores of 1-2. After adjustment, the risk for premature tooth loss was 13.5 times higher in CH apexification, approximately 2 to 4 times higher in PAI 3-5, and 5.6 times higher in avulsions. Conclusion: According to the published literature, both RET and apexification techniques have equal rates of success, survival, and effectiveness in the treatment of immature necrotic permanent teeth, although only RET stimulates root maturation. Knowledge gaps were identified regarding the treatment and follow-up protocols for both techniques. When successful, RET provides satisfactory clinical and radiographical outcomes. The failed cases were related to lack of bleeding and persistent infections, indicating that new techniques are needed to improve the predictability of RET. For microbiological outcomes, there were no statistical differences in CH and CHD efficacy. After root canal dressing (S5), microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. Compared to the failed outcomes, the successful outcomes presented higher diversity and higher decreases of the primary microflora at S5. Only the failed cases had significant increases in abundance and diversity at S5. The analysis of the long-term outcomes identified CH apexification, avulsion, and postoperative PAI of 3-5 as prognostic variables with significant negative impact on the risk for premature tooth loss. List of scientific papers I. What is the best long-term treatment modality for immature permanent teeth with pulp necrosis and apical periodontitis? Wikström A, Brundin M, Lopes MF, El Sayed M, Tsilingaridis G. Eur Arch Paediatr Dent. 2021;22(3):311-340 https://doi.org/10.1007/s40368-020-00575-1 II. Endodontic pulp revitalization in traumatized necrotic immature permanent incisors: Early failures and long-term outcomes - A longitudinal cohort study. Wikström A, Brundin M, Romani Vestman N, Rakhimova O, Tsilingaridis G. Int Endod J. 2022;55(6):630-645 https://doi.org/10.1111/iej.13735 III. Microbiological assessment of success and failure in pulp revitalization: A randomized clinical trial using calcium hydroxide and chlorhexidine gluconate in traumatized immature teeth. Wikström A, Romani Vestman N, Rakhimova O, Gimeno DL, Tsilingaridis G, Brundin M. J Oral Microbiol. 2024 Apr 24;16(1):2343518 https://doi.org/10.1080/20002297.2024.2343518 IV. Outcomes of apexification in immature traumatized necrotic teeth and risk factors for premature tooth loss: A 20-year longitudinal study. Wikström A, Brundin M, Mohmud A, Andersson M, Tsilingaridis G. Dent Traumatol. 2024 Dec;40(6):658-671 https://doi.org/10.1111/edt.1297
Sexual Problems in Patients Suffering from Multiple Sclerosis
No full text Sexual problems in patients suffering from multiple sclerosis. Lilius, H. G., Valtonen, E. J. and Wikström, J. (Departments of Physical Medicine and Neurology, University Central Hospital, Helsinki, Finland). A questionnaire which allowed anonymous answering and which also included many other questions besides those dealing with sexual life was sent to 302 patients suffering from multiple sclerosis (MS). Sexual life had changed for 91% of males and 72% of females. About half of the patients replied that their sexual life was unsatisfactory or had ceased altogether. These patients were as a rule in a relative poor physical condition. In males, disturbances in erection (62%) were the most common problem, erection was normal in only 20%. In females the essential figures were: loss of orgasm in 33%, loss of libido in 27% and spasticity in 12%. There was no correlation between the incidence of sexual disturbances and the duration of the MS. It seems that the neurological disturbances in sexual life depend simply on the location of the plaques in the central nervous system. </jats:p
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