External timber quality of birch in birch-spruce mixtures

The Swedish forest management model, largely based on monocultures of conifer species, has increasingly come under scrutiny. Its disadvantages to biodiversity, recreation and climate change susceptibility incentivize alternative ways of forest production. Mixtures with a secondary species is one such alternative. Birch and spruce, two species native to Sweden, are well-known to function together. Mixtures of the two exist today already, although the species are usually treated with different goals in mind. Further encouragement of forest owners is necessary for the practice to become more widespread. This thesis attempts to reflect upon whether naturally regenerated birch in birch-spruce mixtures have a high enough timber quality to make the birch valuable from an economic perspective. The aim of the study was therefore to assess external timber quality of naturally regenerated birch in birch-spruce mixtures in southern Sweden. The hypotheses to be addressed was a) that naturally regenerated birch trees in Norway spruce plantations fulfill the requirements for high quality saw timber and b) that the quality of the future crop trees of birch is lower when the surrounding competition is of Norway spruce instead of other birches. Birch quality was assessed externally in 27 birch-spruce mixture stands in Götaland. Straightness, leaning, stem damage, spike knots and forks were among the studied variables. The result showed that naturally regenerated birch trees in Norway spruce plantations generally did not fulfill the requirements for high quality saw timber, but had a potential for intermediate quality saw timber. Furthermore, the quality of the future crop trees of birch was lower when the surrounding competition was Norway spruce instead of other birches. The actual cause for the differences is not possible to state with this type of forest survey, where the earlier management is uncertain and the objectives of the different forest owners are unknown. Further research is needed to clarify this, and to determine how to achieve an optimization of birch-spruce mixtures, with yields of both high quality birch timber and spruce timber.Svensk skogsskötsel och dess traditionella fokus på monokulturer av barrträd, har mer och mer ifrågasatts. Dess nackdelar för biodiversitet, rekreation samt känslighet för klimatförändringar ger skäl att undersöka alternativa system för skogsskötsel. Blandskogar, där ett sekundärt trädslag introduceras, är ett sådant alternativ. Björk och gran är inhemska arter i Sverige, och är väl kända att fungera tillsammans. Blandningar av de två existerar redan idag, om än oftast med olika mål för trädslagen. Skogsägare tycks dock behöver ytterligare uppmuntring för att dessa blandskogar ska bli vanligare. Denna uppsats försöker begrunda huruvida björk i björk-gran-blandskogar är av tillräckligt god kvalitet för att den ska vara lönsam ur ett ekonomiskt perspektiv. Målet med undersökningen var därför att skatta extern virkeskvalitet hos naturligt föryngrad björk i björk-gran-blandskogar i Götaland. Hypoteserna var a) att naturligt föryngrad björk i granbestånd når kvalitetskraven för hög virkeskvalitet och b) att kvaliteten hos framtida huvudstammar är lägre när den omgivande konkurrensen är av gran snarare än björk. Björkkvalitet skattades externt i 27 björk-gran-bestånd i Götaland. Stammars rakhet och lutning, samt stamskador, torrkvistar och stamklykor var variabler som registrerades. Resultatet visade att naturligt föryngrad björk i björk-gran-bestånd generellt inte uppfyllde kvalitetskraven för hög virkeskvalitet. Dock tycks det finnas viss potential för sågtimmer av intermediär kvalitet. Dessutom var kvaliteten av de framtida huvudstammarna lägre när den omgivande konkurrensen var av gran snarare än björk. De faktiska skälen bakom dessa skillnader är ej möjliga att utröna med denna typ av undersökning, där beståndens tidigare skötsel samt skogsägarnas mål är okända. Ytterligare forskning behövs för att klargöra detta, samt för att optimera björk-gran-skogsskötsel generellt

Automatic filtering of outliers in RR intervals before analysis of heart rate variability in Holter recordings: a comparison with carefully edited data

<p>Abstract</p> <p>Background</p> <p>Undetected arrhythmic beats seriously affect the power spectrum of the heart rate variability (HRV). Therefore, the series of RR intervals are normally carefully edited before HRV is analysed, but this is a time consuming procedure when 24-hours recordings are analysed. Alternatively, different methods can be used for automatic removal of arrhythmic beats and artefacts. This study compared common frequency domain indices of HRV when determined from manually edited and automatically filtered RR intervals.</p> <p>Methods and Results</p> <p>Twenty-four hours Holter recordings were available from 140 healthy subjects of age 1-75 years. An experienced technician carefully edited all recordings. Automatic filtering was performed using a recursive procedure where RR intervals were removed if they differed from the mean of the surrounding RR intervals with more than a predetermined limit (ranging from 10% to 50%). The filtering algorithm was evaluated by replacing 1% of the beats with synthesised ectopic beats. Power spectral analysis was performed before and after filtering of both the original edited data and the noisy data set. The results from the analysis using the noisy data were used to define an age-based filtering threshold. The age-based filtration was evaluated with completely unedited data, generated by removing all annotations from the series of RR intervals, and then comparing the resulting HRV indices with those obtained using edited data. The results showed equivalent results after age-based filtration of both the edited and unedited data sets, where the differences in HRV indices obtained by different preprocessing methods were small compared to the mean values within each age group.</p> <p>Conclusions</p> <p>The study showed that it might not be necessary to perform the time-consuming careful editing of all detected heartbeats before HRV is analysed in Holter recordings.</p> <p>In most subjects, it is sufficient to perform the regular editing needed for valid arrhythmia analyses, and then remove undetected ectopic beats and artefacts by age-based filtration of the series of RR intervals, particularly in subjects older than 30 years.</p

Screening for atrial fibrillation with baseline and intermittent ECG recording in an out-of-hospital population

BACKGROUND: the objective of this study is to investigate the detection rate of undiagnosed atrial fibrillation (AF) with short intermittent ECG recordings during four weeks among out-of-hospital patients, having at least one additional risk factor (CHADS(2)) for stroke. METHOD: Design: Cross-sectional study. Setting: Eight family practice centres and two hospital-based out-patient clinics in Sweden. Subjects: 989 out-of-hospital patients, without known AF, having one or more risk factors associated with stroke (CHADS(2)). Interventions: All individuals were asked to perform 10-second handheld ECG recordings during 28 days, twice daily and when having palpitations. Main outcome measures: Episodes of AF on handheld ECG recordings were defined as irregular supraventricular extrasystoles in series with a duration of 10 seconds. RESULTS: 928 patients completed registration. AF was found in 35 of 928 patients; 3.8% (95% confidence interval [CI] 2.7–5.2). These 35 patients had a mean age of 70.7 years (SD ± 7.7; range 53–85) and a median CHADS(2) of 2 (range 1–4). CONCLUSIONS: Intermittent handheld ECG recording over a four week period had a detection rate of 3.8% newly diagnosed AF, in a population of 928 out-of-hospital patients having at least one additional risk factor for stroke. Intermittent handheld ECG registration is a feasible method to detect AF in patients with an increased risk of stroke in whom oral anticoagulation (OAC) treatment is indicated

Distansskogsägares självbild, värden och behov

Urbaniseringen har lett till att fler människor har flyttat från landsorten till städerna, vilket har gjort distansskogsägare till en betydande grupp. Frågan är huruvida dessa skiljer sig från övriga skogsägare. I ett försök att identifiera skillnaderna mellan distansskogsägare och övriga skogsägare upprättades ett samarbete med skogsägarföreningen Norra, vars representanter visade på osäkerhet i förhållningen till distansskogsägare. En annan oro gällde den ökande graden av delägande bland skogsägare. Syftet var att undersöka hur olika typer av distansskogsägare förhåller sig till sitt skogsägande avseende följande aspekter: 1. skogsägaridentiteten, d.v.s. vad de har för självbild som skogsägare 2. vilka de värden de får ut av sin skog, samt 3. vilket stöd de upplever sig få eller önskar få från skogsägarföreningen Ett frågeformulär skapades utifrån frågeställningarna och skickades ut per brev till 849 skogsägare med adresser ur skogsägarföreningen Norras databas. Svarsfrekvensen blev endast drygt 20 %, varför resultaten är mycket osäkra. Resultatet visar att skogsägare boende mer än 400 km ifrån sin skogsfastighet identifierar sig som skogsägare i mindre grad än mer närboende. Med det ökande avståndet mellan bostad och fastighet ökar dock markant betydelsen av skogen som arvegods. Vad gäller skogsägarnas önskade stöd framkommer att med ökat avstånd blir telefon som medium för information och rådgivning mindre aktuellt, medan fysiska träffar alltjämt tycks vara gångbart. Dessutom visades skillnader mellan ensam- och delägare, där ensamägare fastlogs i högre grad identifiera sig i rollen som skogsägare. Ensamägare föredrog även i högre grad personlig kontakt eller kontakt per brev, jämfört med e-post som föredrogs av delägare i högre grad.The rate of urbanisation has meant more people moving from rural to urban environments, thus making distance forest owners a significant group. The question is whether these differ from other forest owners. In an attempt to investigate the differences between distance forest owners and other, more close-living, forest owners, a collaboration was initiated with the forest owners association Norra, themselves expressing insecurity in the matter. Another matter of concern for Norra appeared to be the increasing number of joint-ownership among forest owners. The purpose was to study how different types of forest owners, with particular focus on distance owners, would answer in regard to the following: a) their identity as forest owners, b) the values they see in their forest, and c) the support they receive or would like to receive from the forest owners association A survey was created from the question formulations and was sent by letter to 849 forest owners with adresses from Norra’s database. The answering frequency reached just over 20 %, whereas the results are uncertain. The results shows that forest owners living more than 400 km from their forest holding possess an identity as forest owners in a lower degree than the more close-living. With increasing distance between residence and forest holding though, the importance and value of the forest as a family legacy is increasing explicitly. Regarding their desired support, it was evident that increasing distance makes contact by telephone less desirable, while meeting face to face all the while is a suitable alternative. Differences between sole-owners and part-owners were evident, where sole-owners possess the identity as forest owners in a higher degree than part-owners. They also in a higher degree preferred to meet face to face or contact by letter, whereas e-mail was preferred by part-owners

Body mass index, mini nutritional assessment, and their association with five-year mortality in very old people

Objectives: To investigate the prevalence of malnutrition and the association between Body Mass Index (BMI), Mini Nutritional Assessment (MNA) and five-year mortality in a representative population of very old (>85 years) people. Design: A prospective cohort study. Setting: A population-based study of very old people in northern Sweden and western Finland, living in institutional care or in the community. Participants: Out of 1195 potential participants, 832 were included (mean age 90.2[+ or -]4.6 years). Measurements: Nutritional status was assessed using BMI and MNA and the association of those two variables with five-year mortality was analyzed. Results: The mean BMI value for the whole population was 25.1[+ or -]4.5 kg/m2, with no difference between genders (P=0.938). The mean MNA score was 22.5[+ or -]4.6 for the whole sample, and it was lower for women than for men (PA<0.001). Thirteen percent were malnourished (MNA<17) and 40.3% at risk of malnutrition (MNA 17--23.5) according to MNA. Also, 34.8% of those with a MNA score A<17 still had a BMI value a[yen]22.2 kg/m2. A BMI value A<22.2 kg/m2 and a MNA scoreA<17 were associated with lower survival. The association with mortality seemed to be J-shaped for BMI, and linear for MNA. Conclusions: Malnutrition according to MNA was common, but a substantial portion of those with a low MNA score still had a high BMI value, and vice versa. The association with mortality appeared to be J-shaped for BMI, and linear for MNA. The MNA seems to be a good measurement of malnutrition in very old people, and BMI might be misleading and could underestimate the prevalence of malnutrition, especially in women

Encumbered by vulnerability and temporality - the meanings of trigger situations when learning to live with diabetes

AIMS AND OBJECTIVES: The aim of the study was to illuminate the meanings of trigger situations experienced in everyday life when learning to live with diabetes. BACKGROUND: Adults become active learners when faced with situations they do not know how to manage, triggering a need to understand something in a different way than before. Knowing more about experiential learning for persons living with diabetes is important for understanding how learning can be supported by health care. DESIGN: A life-world approach with a phenomenological hermeneutical method, inspired by the philosophy of Paul Ricoeur. METHODS: This method was used for interpreting transcriptions of interviews and consists of three stages: naïve understanding, structural analysis and a comprehensive understanding. Participants (n = 13), with either type I or type II diabetes, were interviewed on three different occasions over a three-year period after being diagnosed with diabetes. RESULTS: When learning to live with diabetes, the meanings of trigger situations were described as 'the unpredictable body heightens insecurity with awareness of one's own dependability', 'losing control in unsustainable situations' and 'encumbered by vulnerability and temporality in earlier familiar situations'. CONCLUSION: The meanings of trigger situations were to lose the smooth, unreflected way of managing an everyday life situation, interlaced with feelings of lost control of how to live with new insights of being vulnerable. Trigger situations meant an opportunity for learning, as well as being demanding, unplanned and with limited freedom of choice. Trigger situations presented life and body as unpredictable. RELEVANCE TO CLINICAL PRACTICE: If healthcare professionals can identify the worries and questions raised in trigger situations, knowledge gaps can be identified and reflected on to stimulate learning