74 research outputs found

    Svartelistearter i Bergen - En trussel for det biologiske mangfoldet?

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    The subject of this Masters thesis is alien species; a topic of increasing debate within the field of biogeography in recent years. Alien species are species that, aided by human activity, are able to spread beyond the natural extent of their habitats. These species play different roles within their adopted ecosystems; some complement the naturally occurring flora and fauna while others dominate and out-compete it leading to a loss in biodiversity. In the latter case the alien species is referred to as invasive. The aim of this thesis has been to study three black-listed, alien species in the wider Bergen area as well as one red-listed native species. The three black-listed species are Japanese knotweed (Reynoutria japonica), Giant knotweed (Reynoutria sachalinensis) and Giant hogweed (Heracleum mantegazzianum). The red-listed species is Masterwort (Peucedanum ostruthium). A theoretical framework for the thesis is provided in Chapter 3. This includes the themes of biological diversity, the definition of invasive species (both native and alien) and the concept of biological invasion and factors determining its success. Three sources have been used in this study. The first is a collection of maps produced by the author from GPS data gathered during fieldwork and processed with GIS. These maps show the current extent of the four species within the area of study. The second source is the national database for species data Artsdatabanken. Comparing the historical database data with the new fieldwork data allows for a (limited) evaluation of the spreading of the four species over time. The third source of information for this study is a series of interviews with stakeholders from the spheres of public administration and academia. Their different, and at times conflicting, opinions are compared and contrasted. The Discussion chapter considers the types of habitats where the species have most successfully established themselves and whether the black-listed species should be considered an invasive threat to the study area. One of the main finds is that they haven't established themselves in areas of natural vegetation, despite having been present in the area for a long time. Furthermore, the distinction between red-listed and black-listed species is considered and its practical implications. Drawing on the interview material, the actions and opinions of the different stakeholders are compared to the theoretical framework. Another of the main finds of the study is that the interviewee from academia is more interested in why the species spread whereas the others are focused on how to tackle this spreading.GEO350MASV-GEO

    «SÄ det gÄr liksom hÄnd i hÄnd det der faglige og sosiale»: En kvalitativ masteroppgave om lÊreres arbeid for inkludering og integrering av minoritetssprÄklige elever pÄ ungdomstrinnet.

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    Hensikten med denne studien var Ä besvare problemstillingen «Hvordan kan lÊrere tilrettelegge for inkludering og integrering av minoritetssprÄklige elever pÄ ungdomstrinnet?». For Ä fÄ et helhetlig bilde av dette inkluderingsarbeidet og integreringsprosessen, ble det utformet tre forskningsspÞrsmÄl som omhandlet: (1) hvilke tiltak lÊrere gjennomfÞrer for Ä tilrettelegge for inkludering av minoritetssprÄklige elever og hvordan disse oppleves Ä fungere, (2) hva lÊrere opplever som utfordrende i inkluderingsarbeidet og (3) hva lÊrere opplever at kan forbedres i inkluderingsarbeidet. Et akkulturasjonsrammeverk ble benyttet for Ä forstÄ de ulike faktorene som pÄvirker minoritetssprÄklige elevers inkludering i skolen. Studien hadde et kvalitativt design, og det ble benyttet semistrukturerte intervjuer for Ä samle inn data. Informantene bestod av seks lÊrere som arbeidet i ordinÊr klasse pÄ ungdomstrinnet, og en lÊrer som arbeidet i et innfÞringstilbud med arbeidsoppgave Ä bistÄ lÊrere og elever i overgangen til ordinÊr undervisning. Funnene som ble gjort i studien antydet at bruk av de minoritetssprÄklige elevenes bakgrunn i undervisningen var et positivt tiltak i inkluderingsarbeidet. Det ble ogsÄ gjort funn som antydet at den sosiale inkluderingen mÄ forstÄs som et samspill av flere pÄvirkende faktorer, men at det kunne ha en positiv virkning med flere minoritetssprÄklige elever i samme skoleklasse. Imidlertid ble det gjort funn av at de minoritetssprÄklige elevenes manglende norskkunnskaper opplevdes som den stÞrste utfordringen i inkluderingsarbeidet, og at sprÄkopplÊringen derfor burde styrkes. Funnene antydet ogsÄ at det er behov for flere ressurser med kompetanse om minoritetssprÄklige elever i skolen, som kan hjelpe lÊrerne med tilrettelegging i den ordinÊre undervisningen

    Increasing but levelling out risk of revision due to infection after total hip arthroplasty: a study on 108,854 primary THAs in the Norwegian Arthroplasty Register from 2005 to 2019

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    Background and purpose — Focus on prevention, surveillance, and treatment of infection after total hip arthroplasty (THA) in the last decade has resulted in new knowledge and guidelines. Previous publications have suggested an increased incidence of surgical revisions due to infection after THA. We assessed whether there have been changes in the risk of revision due to deep infection after primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 2005–2019. Patients and methods — Primary THAs reported to the NAR from January 1, 2005 to December 31, 2019 were included. Adjusted Cox regression analyses with the first revision due to deep infection after primary THA were performed. We investigated changes in the risk of revision as a function of time of primary THA. Time was stratified into 5-year periods. We studied the whole population of THAs, and the subgroups: all-cemented, all-uncemented, reverse hybrid (cemented cup), and hybrid THAs (cemented stem). In addition, we investigated factors that were associated with the risk of revision, and changes in the time span from primary THA to revision. Results — Of the 108,854 primary THAs that met the inclusion criteria, 1,365 (1.3%) were revised due to deep infection. The risk of revision due to infection, at any time after primary surgery, increased through the period studied. Compared with THAs implanted in 2005–2009, the relative risk of revision due to infection was 1.4 (95% CI 1.2–1.7) for 2010–2014, and 1.6 (1.1–1.9) for 2015–2019. We found an increased risk for all types of implant fixation. Compared to 2005–2009, for all THAs, the risk of revision due to infection 0–30 days postoperatively was 2.2 (1.8–2.8) for 2010–2014 and 2.3 (1.8–2.9) for 2015–2019, 31–90 days postoperatively 1.0 (0.7–1.6) for 2010–2014 and 1.6 (1.0–2.5) for 2015–2019, and finally 91 days–1 year postoperatively 1.1 (0.7–1.8) for 2010–2014 and 1.6 (1.0–2.6) for 2015–2019. From 1 to 5 years postoperatively, the risk of revision due to infection was similar to 2005–2009 for both the subsequent time periods Interpretation — The risk of revision due to deep infection after THA increased throughout the period 2005–2019, but appears to have levelled out after 2010. The increase was mainly due to an increased risk of early revisions, and may partly have been caused by a change of practice rather than a change in the incidence of infection.publishedVersio

    Amoxicillin did not Reduce Modic Change Oedema in Patients with Chronic Low Back pain - subgroup Analyses of a Randomised Trial (the AIM study)

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    Study Design. Exploratory subgroup analyses of a randomised trial [Antibiotics in Modic changes (AIM) study]. Objective. The aim was to assess the effect of amoxicillin versus placebo in reducing Modic change (MC) edema in patients with chronic low back pain. Summary of Background Data. The AIM study showed a small, clinically insignificant effect of amoxicillin on pain-related disability in patients with chronic low back pain and MC type 1 (edema type) on magnetic resonance imaging (MRI). Materials and Methods. A total of 180 patients were randomised to receive 100 days of amoxicillin or placebo. MC edema was assessed on MRI at baseline and one-year follow-up. Per-protocol analyses were conducted in subgroups with MC edema on short tau inversion recovery (STIR) or T1/T2-weighted MRI at baseline. MC edema reductions (yes/no) in STIR and T1/T2 series were analyzed separately. The effect of amoxicillin in reducing MC edema was analyzed using logistic regression adjusted for prior disk surgery. To assess the effect of amoxicillin versus placebo within the group with the most abundant MC edema on STIR at baseline (“STIR3” group), we added age, STIR3 (yes/no), and STIR3×treatment group (interaction term) as independent variables and compared the marginal means (probabilities of edema reduction). Results. Compared to placebo, amoxicillin did not reduce MC edema on STIR (volume/intensity) in the total sample with edema on STIR at baseline (odds ratio 1.0, 95% CI: 0.5, 2.0; n=141) or within the STIR3 group (probability of edema reduction 0.69, 95% CI: 0.47, 0.92 with amoxicillin and 0.61, 95% CI: 0.43, 0.80 with placebo; n=41). Compared with placebo, amoxicillin did not reduce MC edema in T1/T2 series (volume of the type 1 part of MCs) (odds ratio: 1.0, 95% CI: 0.5, 2.3, n=104). Edema declined in >50% of patients in both treatment groups. Conclusions. From baseline to one-year follow-up, amoxicillin did not reduce MC edema compared with placebo.publishedVersio

    Amoxicillin did not Reduce Modic Change Oedema in Patients with Chronic Low Back pain - subgroup Analyses of a Randomised Trial (the AIM study)

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    Study Design. Exploratory subgroup analyses of a randomised trial (Antibiotics In Modic changes (AIM) study). Objective. To assess the effect of amoxicillin versus placebo in reducing Modic change (MC) oedema in patients with chronic low back pain (LBP). Summary of Background Data. The AIM study showed a small, clinically insignificant effect of amoxicillin on pain-related disability in patients with chronic LBP and MC type 1 (oedema type) on magnetic resonance imaging (MRI). Methods. A total of 180 patients were randomised to receive 100 days of amoxicillin or placebo. MC oedema was assessed on MRI at baseline and one-year follow-up. Per-protocol analyses were conducted in subgroups with MC oedema on short tau inversion recovery (STIR) or T1/T2-weighted MRI at baseline. MC oedema reductions (yes/no) in STIR and T1/T2-series were analysed separately. The effect of amoxicillin in reducing MC oedema was analysed using logistic regression adjusted for prior disc surgery. To assess the effect of amoxicillin versus placebo within the group with the most abundant MC oedema on STIR at baseline (‘STIR3’ group), we added age, STIR3 (yes/no), and STIR3×treatment group (interaction term) as independent variables and compared the marginal means (probabilities of oedema reduction). Results. Compared to placebo, amoxicillin did not reduce MC oedema on STIR (volume/intensity) in the total sample with oedema on STIR at baseline (odds ratio 1.0, 95% confidence interval (95%CI) [0.5, 2.0]; n=141) or within the STIR3 group (probability of oedema reduction 0.69, 95%CI [0.47, 0.92] with amoxicillin and 0.61, 95%CI [0.43, 0.80] with placebo; n=41). Compared with placebo, amoxicillin did not reduce MC oedema in T1/T2-series (volume of the type 1 part of MCs) (odds ratio 1.0, 95%CI [0.5, 2.3], n=104). Oedema declined in >50% of patients in both treatment groups. Conclusions. From baseline to one-year follow-up, amoxicillin did not reduce MC oedema compared with placebo. Level of Evidence. Level 2

    Periprosthetic Joint Infection After Total Knee Arthroplasty With or Without Antibiotic Bone Cement.

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    IMPORTANCE Despite increased use of antibiotic-loaded bone cement (ALBC) in joint arthroplasty over recent decades, current evidence for prophylactic use of ALBC to reduce risk of periprosthetic joint infection (PJI) is insufficient. OBJECTIVE To compare the rate of revision attributed to PJI following primary total knee arthroplasty (TKA) using ALBC vs plain bone cement. DESIGN, SETTING, AND PARTICIPANTS This international cohort study used data from 14 national or regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, New Zealand, Norway, Romania, Sweden, Switzerland, the Netherlands, the UK, and the US. The study included primary TKAs for osteoarthritis registered from January 1, 2010, to December 31, 2020, and followed-up until December 31, 2021. Data analysis was performed from April to September 2023. EXPOSURE Primary TKA with ALBC vs plain bone cement. MAIN OUTCOMES AND MEASURES The primary outcome was risk of 1-year revision for PJI. Using a distributed data network analysis method, data were harmonized, and a cumulative revision rate was calculated (1 - Kaplan-Meier), and Cox regression analyses were performed within the 10 registries using both cement types. A meta-analysis was then performed to combine all aggregated data and evaluate the risk of 1-year revision for PJI and all causes. RESULTS Among 2 168 924 TKAs included, 93% were performed with ALBC. Most TKAs were performed in female patients (59.5%) and patients aged 65 to 74 years (39.9%), fully cemented (92.2%), and in the 2015 to 2020 period (62.5%). All participating registries reported a cumulative 1-year revision rate for PJI of less than 1% following primary TKA with ALBC (range, 0.21%-0.80%) and with plain bone cement (range, 0.23%-0.70%). The meta-analyses based on adjusted Cox regression for 1 917 190 TKAs showed no statistically significant difference at 1 year in risk of revision for PJI (hazard rate ratio, 1.16; 95% CI, 0.89-1.52) or for all causes (hazard rate ratio, 1.12; 95% CI, 0.89-1.40) among TKAs performed with ALBC vs plain bone cement. CONCLUSIONS AND RELEVANCE In this study, the risk of revision for PJI was similar between ALBC and plain bone cement following primary TKA. Any additional costs of ALBC and its relative value in reducing revision risk should be considered in the context of the overall health care delivery system

    The use of antibiotic-loaded bone cement and systemic antibiotic prophylactic use in 2,971,357 primary total knee arthroplasties from 2010 to 2020: an international register-based observational study among countries in Africa, Europe, North America, and Oceania.

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    BACKGROUND AND PURPOSE Antibiotic-loaded bone cement (ALBC) and systemic antibiotic prophylaxis (SAP) have been used to reduce periprosthetic joint infection (PJI) rates. We investigated the use of ALBC and SAP in primary total knee arthroplasty (TKA). PATIENTS AND METHODS This observational study is based on 2,971,357 primary TKAs reported in 2010-2020 to national/regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, the Netherlands, New Zealand, Norway, Romania, South Africa, Sweden, Switzerland, the UK, and the USA. Aggregate-level data on trends and types of bone cement, antibiotic agents, and doses and duration of SAP used was extracted from participating registries. RESULTS ALBC was used in 77% of the TKAs with variation ranging from 100% in Norway to 31% in the USA. Palacos R+G was the most common (62%) ALBC type used. The primary antibiotic used in ALBC was gentamicin (94%). Use of ALBC in combination with SAP was common practice (77%). Cefazolin was the most common (32%) SAP agent. The doses and duration of SAP used varied from one single preoperative dosage as standard practice in Bolzano, Italy (98%) to 1-day 4 doses in Norway (83% of the 40,709 TKAs reported to the Norwegian arthroplasty register). CONCLUSION The proportion of ALBC usage in primary TKA varies internationally, with gentamicin being the most common antibiotic. ALBC in combination with SAP was common practice, with cefazolin the most common SAP agent. The type of ALBC and type, dose, and duration of SAP varied among participating countries

    Schmidt-hammer exposure ages from periglacial patterned ground (sorted circles) in Jotunheimen, Norway, and their interpretative problems

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    © 2016 Swedish Society for Anthropology and Geography Periglacial patterned ground (sorted circles and polygons) along an altitudinal profile at Juvflya in central Jotunheimen, southern Norway, is investigated using Schmidt-hammer exposure-age dating (SHD). The patterned ground surfaces exhibit R-value distributions with platycurtic modes, broad plateaus, narrow tails, and a negative skew. Sample sites located between 1500 and 1925 m a.s.l. indicate a distinct altitudinal gradient of increasing mean R-values towards higher altitudes interpreted as a chronological function. An established regional SHD calibration curve for Jotunheimen yielded mean boulder exposure ages in the range 6910 ± 510 to 8240 ± 495 years ago. These SHD ages are indicative of the timing of patterned ground formation, representing minimum ages for active boulder upfreezing and maximum ages for the stabilization of boulders in the encircling gutters. Despite uncertainties associated with the calibration curve and the age distribution of the boulders, the early-Holocene age of the patterned ground surfaces, the apparent cessation of major activity during the Holocene Thermal Maximum (HTM) and continuing lack of late-Holocene activity clarify existing understanding of the process dynamics and palaeoclimatic significance of large-scale sorted patterned ground as an indicator of a permafrost environment. The interpretation of SHD ages from patterned ground surfaces remains challenging, however, owing to their diachronous nature, the potential for a complex history of formation, and the influence of local, non-climatic factors

    Small rock-slope failures conditioned by Holocene permafrost degradation:a new approach and conceptual model based on Schmidt-hammer exposure-age dating, Jotunheimen, southern Norway

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    Rock-slope failures (RSFs) constitute significant natural hazards but the geophysical processes which control their timing are poorly understood. However, robust chronologies can provide valuable information on the environmental controls on RSF occurrence: information which can inform models of RSF activity in response to climatic forcing. This paper uses Schmidt-hammer exposure-age dating (SHD) of boulder deposits to construct a detailed regional Holocene chronology of the frequency and magnitude of small rock-slope failures (SRSFs) in Jotunheimen, Norway. By focusing on the depositional fans of SRSFs (≀ 103 m3), rather than on the corresponding features of massive RSFs (~108 m3), 92 single-event RSFs are targeted for chronology building. A weighted SHD age-frequency distribution and probability density function analysis indicate four centennial- to millennial-scale periods of enhanced SRSF frequency, with a dominant mode at ~4.5 ka. Using change detection and discreet Meyer wavelet analysis, in combination with existing permafrost depth models, we propose that enhanced SRSF activity was primarily controlled by permafrost degradation. Long-term relative change in permafrost depth provides a compelling explanation for the high-magnitude departures from the SRSF background rate and accounts for (i1) the timing of peak SRSF frequency, (2ii) the significant lag (~2.2 ka) between the Holocene Thermal Maximum and the SRSF frequency peak, and (3iii) the marked decline in frequency in the late-Holocene. This interpretation is supported by geomorphological evidence, as the spatial distribution of SRSFs is strongly correlated with the aspect-dependent lower altitudinal limit of mountain permafrost in cliff faces. Results are indicative of a causal relationship between episodes of relatively warm climate, permafrost degradation and the transition to a seasonal-freezing climatic regime. This study highlights permafrost degradation as a conditioning factor for cliff collapse, and hence the importance of paraperiglacial processes; a result with implications for slope instability in glacial and periglacial environments under global warming scenarios
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