Snow covered area estimation using space-borne radar

Tässä työssä tutkitaan TKK:n Avaruustekniikan laboratoriossa kehitetyn lumenpeittoalan estimointimenetelmän tarkkuutta. Tärkeimpänä tavoitteena on menetelmän tilastollisen tarkkuuden selvittäminen. Toissijaisesti tutkitaan myös referenssikuvien valinnan, metsäkompensoinnin, maaston topografian ja satelliitin lentoradan vaikutuksia lumenpeittoalan estimointiin. Menetelmää tutkitaan suorittamalla lumenpeittoalan estimointi 24:lle ERS-2 SAR satelliittikuvalle pohjois-Suomen havumetsävaltaiselle koealueelle. Menetelmän tarkkuuden arviointi suoritetaan vertaamalla saatuja estimointituloksia referenssiaineistoon.An accuracy analysis of the HUT Snow Covered Area estimation method is presented in this work. The main emphasis is to resolve the statistical accuracy of the estimation method. Other studied subjects include the effects of reference image selection, forest compensation, topography and satellite flight path on the SCA estimation method. The method is studied by conducting the SCA estimation for 24 ERS-2 SAR intensity images for the boreal forest dominated test area in Northern Finland. The evaluation of the method is conducted by comparing the SCA estimation results with the available reference data

Remote sensing of snow-cover for the boreal forest zone using microwave radar

This doctoral dissertation describes the development of an operationally feasible snow monitoring methodology utilizing spaceborne synthetic aperture radar (SAR) imagery, intended for hydrological applications on the boreal forest zone. The snow-covered area (SCA) estimation methodology developed is characterized using extensive satellite-based datasets, including SAR-based estimation and optical reference data gathered during the snow-melt seasons of 1997-1998, 2000-2002 and 2004-2006 from northern Finland. The methodology applies satellite-based C-band SAR data for snow monitoring during the spring snow-melt season. The SCA information can be utilized for river discharge forecasting and flood predictions and for the optimization of hydropower production. The development efforts included 1) demonstration of a forest compensation algorithm, 2) establishing the use of wide-swath SAR data 3) development of a weather station assimilation procedure and 4) creation of an enhanced reference image selection algorithm for the SCA estimation methodology. The feasibility of a proposed, non-boreal forest specific, SAR-based SCA estimation method was evaluated for the boreal forest zone. The acquired results were compared with the characteristics determined for the boreal-forest specific methodology developed within this dissertation. These results can be used when selecting appropriate SCA estimation approaches for future snow monitoring systems whether conducted in different regions or intended for larger i.e. continental or global scale purposes. An automatic processing system for SCA estimation was developed and demonstrated as part of this work; the system has been delivered to the Finnish Environment Institute for operational use

Tissue engineering of human knee meniscus

The knee menisci are c-shaped fibrocartilaginous structures in the knee joint that have a crucial function in stabilization, shock absorption and load transmission. A knee has two menisci, medial on the inside and lateral on the outside. Meniscus lesions are common knee injuries that typically occur in the form of tears. Current clinical practice is based on removing either the whole meniscus or only a part of it, repairing the meniscus with the help of sutures, arrows, and screws, or utilizing meniscus reconstruction methods to replace the native meniscus. Due to the high incidence in the knee injuries and resulting expenses, tissue-engineered meniscus repair has become a widely investigated option. Traditional meniscus tissue engineering is based on combining three-dimensional support structures called scaffolds, cells, and biochemical and mechanical stimulation to develop an ideal, biocompatible meniscus replacement. Besides scaffold-based approaches, scaffold-free tissue engineering, which does not utilize cell seeding or attachment within an exogenous material, has also gained interest lately. The aim of this literature review is to get acquainted with the different tissue engineering applications related to meniscus. The current commercial applications and the possible applications for the human knee meniscus in the future are described. The contemporary scientific situation of the applications is also discovered, as well as the challenges and advantages related to the tissue engineering applications. This thesis demonstrates that promising meniscus-preserving and -replacing treatment options have been developed. However, additional research is still essential before the solutions can be commercialized

Self-reported sleep disturbance and incidence of dementia in ageing men

Background Sleep disturbance is suggested to contribute to the development of dementia. However, prospective longitudinal data from middle-aged populations are scarce. Methods We investigated a population-based sample of 2386 men aged 42-62 years at baseline during 1984-1989. Participants having a history of mental illnesses, psychiatric medication, Parkinson's disease or dementia within 2 years after baseline (n=296) were excluded. Difficulty falling asleep or maintaining sleep, sleep duration and daytime tiredness were enquired. Dementia diagnoses (n=287) between 1984 and 2014 were obtained through linkage with hospital discharge, national death and special reimbursement registers. Cox proportional hazards analyses were performed for all dementias, and separately for Alzheimer's disease (n=234) and other phenotypes (n=53). Additional analyses were performed on a subsample of an apolipoprotein E (APOE) genotype-tested population (n=1199). Results The risk ratio for dementia was 1.58 (95% CI 1.10 to 2.27) in men with frequent sleep disturbance after adjustments for age, examination year, elevated depressive symptoms, physical activity, alcohol consumption, cumulative smoking history, systolic blood pressure, body mass index, low-density lipoprotein and high-density lipoprotein cholesterol, high-sensitivity C reactive protein, cardiovascular disease history, education years and living alone. Daytime tiredness and sleep duration were not associated with dementia in adjusted analysis. In the APOE subsample, both APOE epsilon 4 genotype and frequent sleep disturbance were associated with increased dementia risk, but in the interaction analysis they had no joint effect. Conclusions Self-reported frequent sleep disturbance in middle-aged men may relate to the development of dementia in later life. Having an APOE e4 genotype did not affect the relationship

Longitudinal Analyses of Diet Quality and Maternal Depressive Symptoms During Pregnancy : The Kuopio Birth Cohort Study

Publisher Copyright: © 2022 Academy of Nutrition and DieteticsBackground: Depression and diet quality appear to be associated in the general population. Nevertheless, little is known about their relationship among pregnant females. Objective: The aims of this study were first, to investigate longitudinally whether or not diet quality is associated with depressive symptoms during pregnancy; second, to examine whether or not variation in diet quality during pregnancy predicts variation in depressive symptoms; and third, to explore how individual dietary components are associated with depressive symptoms. Design: A longitudinal secondary analysis of the Kuopio Birth Cohort Study in eastern Finland was conducted. Data were collected from pregnant females during the first and third trimesters of pregnancy. Participants/setting: The participants were 1,362 pregnant females who entered the study between 2012 and 2017. Main outcome measures: Depressive symptoms, as measured with the Edinburgh Postnatal Depressive Scale during the first and third trimesters of pregnancy were used as continuous variables. Statistical analyses performed: The main analyses consisted of linear mixed model analyses adjusted for potential confounders to longitudinally assess the association between diet quality as measured by the Healthy Eating Index-2015, calculated using data from a food frequency questionnaire completed during the first trimester and third trimester, and depressive symptoms during the study period. An exploratory set of linear mixed models was also used to longitudinally assess the associations between selected individual food frequency questionnaire food groups and depressive symptoms. Results: Descriptive analyses revealed that 12.3% of the participants had clinically relevant levels of depressive symptoms (ie, Edinburgh Postnatal Depressive Scale score ≥10) during either the first or third trimester. Longitudinal modeling suggested that depressive symptoms in pregnant females tend to remain stable throughout pregnancy. Females with a poorer quality diet already displayed higher levels of depressive symptoms during the first trimester of pregnancy (β = –.038 ± .016; P = 0.022). Variation in diet quality did not predict variation in depressive symptoms over the course of pregnancy (β = –9.741 × 10–5 ± .001; P = 0.869). Conclusions: Females entering pregnancy with a poorer quality diet also displayed higher levels of depressive symptoms compared with females with a higher quality diet at the beginning of pregnancy, and this association remained constant throughout pregnancy. Further research is needed to assess the direction and the potential causality of the observed associations between diet quality and depressive symptoms.Peer reviewe

Mental Health Conditions and Nonpersistence of Direct Oral Anticoagulant Use in Patients With Incident Atrial Fibrillation : A Nationwide Cohort Study

BACKGROUND: Mental health conditions (MHCs) are associated with poor outcomes in patients with atrial fibrillation. However, persistence of oral anticoagulation therapy in patients with atrial fibrillation and MHCs is unknown. We aimed to evaluate the effect of MHCs on the persistence of direct oral anticoagulant (DOAC) use in patients with atrial fibrillation based on a nationwide cohort. METHODS AND RESULTS: The nationwide registry-based FinACAF (Finnish Anticoagulation in Atrial Fibrillation) cohort included 67 503 patients with incident atrial fibrillation and indication for permanent oral anticoagulation (CHA(2)DS(2)-VASc score >1 in men and >2 in women) starting DOAC therapy between 2011 and 2018. MHCs of interest were depression, bipolar disorder, anxiety disorder, schizophrenia, and composite of any MHC. The main outcome was nonpersistence of DOAC use, defined as the first 120-day period without DOAC purchases after drug initiation. The mean age of the patients was 75.3 +/- 8.9 years, 53.6% were women, and the prevalence of any MHC was 17.8%. Persistence after 1 year from DOAC initiation was 79.3% in patients without MHCs and 77.2% in patients with any MHC, and after 2 years were 64.4% and 60.6%, respectively (P CONCLUSIONS: MHCs are associated with nonpersistence of DOAC use.Peer reviewe

Mental health conditions and adherence to direct oral anticoagulants in patients with incident atrial fibrillation : A nationwide cohort study

Objective: Medication adherence is essential for effective stroke prevention in patients with atrial fibrillation (AF). We aimed to assess whether adherence to direct oral anticoagulants (DOACs) in AF patients is affected by the presence of mental health conditions (MHCs). Methods: The nationwide FinACAF cohort covered 74,222 AF patients from all levels of care receiving DOACs during 2011-2018 in Finland. Medication possession ratio (MPR) was used to quantify adherence. Patients with MPR >= 0.90 were defined adherent. MHCs of interest were depression, bipolar disorder, anxiety disorder and schizophrenia. Results: The patients' (mean age 75.4 +/- 9.5 years, 50.8% female) mean MPR was 0.84 (SD 0.22), and 59.5% had MPR >= 0.90. Compared to patients without MHC, the adjusted ORs (95% CI) for adherent DOAC use emerged slightly lower in patients with depression (0.92 (0.84-0.99)) and bipolar disorder (0.77 (0.61-0.97)) and unsignificant in patients with anxiety disorder (1.08 (0.96-1.21)) and schizophrenia (1.13 (0.90-1.43)). However, when only persistent DOAC therapy was analyzed, no MHC was associated with poor adherence, and instead anxiety disorder was associated with adherent DOAC use (1.18 (1.04-1.34)). Conclusion: Adherence to DOACs in AF patients in Finland was relatively high, and no meaningful differences between patients with and without MHCs were observed.Peer reviewe

Rural-urban differences in the initiation of oral anticoagulant therapy in patients with incident atrial fibrillation : A Finnish nationwide cohort study

Publisher Copyright: Copyright: © 2022 Teppo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Aims Little is known about rural-urban differences in the treatment and outcomes in patients with atrial fibrillation (AF). We aimed to assess whether the initiation of oral anticoagulant (OAC) therapy in patients with AF differs between those with rural and urban residence. Methods The registry-based FinACAF cohort covers all patients with AF from all levels of care in Finland. Patients were divided into rural and urban categories and into urbanization degree tertiles based on their municipality of residence at the time of AF diagnosis. The outcome was the first redeemed OAC prescription. Results We identified 222 419 patients (50.1% female; mean age 72.8 (SD 13.2) years) with incident AF during 2007–2018. Urban residence was associated with a lower rate of OAC therapy initiation (adjusted subdistribution hazard ratio (SHR) (95% CI) 0.96 (0.95–0.97)). Correspondingly, an inverse graded dose-response relationship was observed between higher urbanization degree tertile and OAC initiation rate (highest tertile compared to lowest: adjusted SHR (95% CI) 0.94 (0.93–0.95)). The adoption of direct oral anticoagulants for stroke prevention was faster among patients with urban residence. Conclusion This nationwide cohort study documented that urban residence is associated with a slightly lower rate of OAC therapy initiation in patients with incident AF, but faster adoption of direct oral anticoagulant use.Peer reviewe