Under sommaren 2014 bröt den största skogsbranden ut i modern svensk historia. Branden startade i närheten av Sala och totalt brann cirka 14 000 ha. Till följd av klimatförändringar förväntas medeltemperaturen öka och nederbörden minska under sommarhalvåret i Sverige, vilket ökar risken för skogsbränder. Skogsbränder kan ha betydande effekter för akvatiska ekosystem och ett flertal studier av skogsbränders effekter har visat på förhöjda halter av näringsämnen, bas- och anjoner. Det branddrabbade området domineras av skogsmark, öppna torvmarker samt sjöar. Området har påverkats av ett intensivt skogsbruk och försurning. Med syfte att analysera brandens hårdhet och dess vattenkemiska effekter, utvärderades och klassificerades brandhårdheten. Analysen indikerade att ökad brandintensitet orsakat ökad brandhårdhet samt att skogsbeklädda dikade torvområden varit känsligare än öppna torvmarker. I området provtogs nio bäckar och tio sjöar. Under de första tre månaderna efter branden observerades höga halter av ammoniumkväve och sulfat i samtliga bäckar och i de flesta sjöarna inom det branddrabbade området. I Gärsjöbäcken var medianhalterna av ammoniumkväve 79 gånger högre efter branden. De höga ammoniumkvävehalterna medförde höga nitratkvävehalter till följd av nitrifikation. Surhet bedöms ofta genom pH och ANC (Acid neutralicing capacity) som är ett vattens förmåga att neutralisera en stark syra. Den initiala sulfatpulsen orsakade en sänkningav ANC i samtliga bäckar. Efter pulsen ökade ANC till följd av ökat läckage av kalium, kalcium och magnesium efter branden. Buffertkapaciteten varierade i bäckarna och i Myckelmossbäcken observerades högst sulfathalter och lägst ANC-värden. I april var ANC fortfarande lägre i Myckelmossbäcken än i övriga bäckar. Totalfosforhalterna ökade efter branden men inte i samma utsträckning som ammoniumkvävehalterna. Korrelationsanalyser gjordes mellan brandhårdhet och vattenkemiska parametrar. Maxhalterna av ammoniumkväve korrelerade positivt med svedd öppen torvmark och hårt brända kronor i skogsbeklädd torvmark. Det indikerade att när organiskt material förbränndes i öppna och skogsbeklädda torvmarker vid måttliga förbränningstemperaturer ökade läckaget av ammoniumkväve. / During the summer of 2014 the largest wildfire in Swedish modern history occurred. The fire was ignited in a forest close to the Swedish town Sala and incinerated a total of 14 000 ha. The frequency of wildfires is expected to increase, due to effects of climate change such as increased temperature and decreased precipitation during the summer months. Wildfires can have a considerable impact on aquatic ecosystems and previous studies of wildfires have shown elevated concentrations of nutrients, cat- and anions. The area of the fire mainly consists of forestland, peatland and lakes and has been affected by acidification and intensive forestry. To assess the fire severity and the effects on the water chemistry, the fire severity was analyzed and classified. The analysis indicated that increased fire intensity caused increased fire severity and that drained forested areas were more vulnerable to fire than undrained peatland. Measurements of water chemistry were conducted at nine streams and ten lakes inside the affected area. During the initial three months of the post-fire period large peaks of ammonium-nitrogen and sulphate were observed in the streams and in a majority of the lakes. In the stream Gärsjöbäcken the median concentrations of ammonium-nitrogen were 79 times higher after the fire. Due to nitrification the elevated concentrations of ammonium-nitrogen caused elevated concentrations of nitrate-nitrogen. ANC (Acid Neutralizing Capacity) and pH are often used to assess the acidity in surface waters, where ANC is the water’s ability to neutralize a strong acid. The initial peak of sulphate caused a drop in ANC but after the peak had past ANC increased due to elevated concentrations of base cations. The measured streams and lakes had different buffering capacity and in one stream Myckelmossbäcken the highest concentrations of sulphate and weakest buffering capacity were observed. In April ANC were still lower in Myckelmossbäcken than in other measured streams. Correlation analysis of fire severity and water chemistry indicated that the maximum concentrations of ammonium-nitrogen increased with severely burned canopies in drained forested peatlands and in scorched open peatland.

After decades of suppression, fire is returning to forests of western United States. Understanding responses of wildlife species to fire is essential to native species conservation because contemporary fires may not have the same effects on forest structure and landscape patterns as historical fires. I used radio-telemetry to investigate effects of fire severity and heterogeneity on habitat selection of Mexican fox squirrels, Sciurus nayaritensis chiricahuae. Vegetation within home ranges was characterized by more open understory and larger trees than random locations. Squirrels used areas burned at low severity more than unburned areas and those burned at higher severities. Squirrels used areas of moderate burn heterogeneity more than areas of low or high heterogeneity. Return of low-severity fire can help restore habitat for Mexican fox squirrels and other native species in forests with a historical regime of low-severity fire and contribute to understanding of the role of fire in forest ecosystems.

Although Autism Spectrum Disorder (ASD) is considered to be a lifelong condition, some toddlers experience diagnostic instability over time. In particular, some toddlers’ diagnosis changes between ASD and Global Developmental Delay (GDD). However, little is known about the subset of children who change diagnosis. In a total of 424 toddlers who either maintained or changed diagnosis, the current study identified predictors of change in diagnosis and severity in those who change from ASD to non-ASD (ASD-NON), ASD to GDD (ASD-GDD), non-ASD to ASD (NON-ASD), and GDD to ASD (GDD-ASD) between two years old and four years old. Initial ASD symptom severity and participation in intervention services were predictive of all transitions. Additionally, receptive language predicted ASD-NON transition and socioeconomic status predicted ASD-GDD transition. Implications for informing prognosis of children, identifying targets of intervention, refining of screening and diagnostic measures, and measuring change in severity regardless of categorical change are discussed.

Interactions among site conditions, disturbance events, and climate determine the patterns of forest species recruitment and mortality across landscapes. Forests of the American Southwest have undergone significant changes over a century of altered disturbance regimes, human land uses, and changing environmental conditions. This study reconstructs the interactions between fire, spruce beetle outbreaks, climate, and anthropogenic factors and their influence on the species composition, spatial extent, and structure of four upper elevation forest types. We found that fire-climate associations changed following fire exclusion and recent high-severity fires occurred during less severe conditions than in several larger, lower severity fires in the historical record. Contemporary fires are burning with higher severity than similarly-sized historical fires, suggesting a shift toward higher-severity fire as a result of changes to forest structure and fuels over much of the upper elevation forest. In high elevation forests, the area occupied by Engelmann spruce and corkbark fir doubled in size over the four decades following fire exclusion. The increase in spruce beetle outbreak size and severity in the 20th century appears to be linked to significant expansion of host extent, accelerated growth of spruce in mixed-conifer forest, and incidence of anomalously warm summer temperatures followed by up to a decade of low precipitation. Trends toward warming, drying conditions are expected to increase the risk of future high-severity outbreaks, especially in locations of recent spruce population expansion. Forest conversion from disturbance-adapted to competition-adapted species following fire exclusion was a function of site productivity. Species assemblages in the lowest and highest productivity sites were the most stable over the century following fire exclusion. Frequent low severity fires maintained the stocking of forests in moderate productivity sites below their biological potential, conferring a degree of resistance to drought, insect outbreaks, and high-severity fire prior to fire exclusion. Current forests located on moderate productivity sites are now the most vulnerable to drought and future disturbance. Aggressive action to restore historical species composition, stocking and fire component of these forests may return resilience to this system in the face of projected changes to fire and climate dynamics.

In the past few decades, wildfires have increased in size and severity in the Southwest and across the western US. These recent trends in fire behavior are a drastic change in arid, ponderosa pine and mixed conifer forests of the Southwest compared with tree-ring records of fire history for the past ~ 400 years. This study presents a late Holocene record (~ 3,000 years) of fire history and related changes in fire regimes with climate variability over annual to multi-decadal time scales. Tree-ring and alluvial-sediment sampling sites were paired in four small, tributary basins located in the western San Juan Mountains of Colorado. In our study sites, tree-ring records show that fire return intervals were longer and fire behavior was more severe on the north-facing slopes with relatively dense mixed conifer stands. Increased fire barriers and steep topography decreased the fire frequency and extent relative to gentle terrain elsewhere in the range and leading to a lack of synchrony among fire years in different parts of the study area. The alluvial-sediment record showed four peaks in high-severity fire activity over the past 3,000 years ranging between 200 - 400 years in length. The timing of peaks coincided with decadal-length drought episodes and were often preceded by multiple decades of above average winter precipitation. The sampling of alluvial-sediment and tree-ring data allowed for site-level comparisons between recent alluvial deposits and specific fire years interpreted from the tree-ring records. We found good correspondence between the type of fire-related sediment deposit (i.e. geomorphic response) in the alluvial record and the extent of mixed and high-severity fire estimated from the tree-ring record, and the correspondence was well-supported by the debris flow probability model results. The two paleofire data tend to represent particular components of the historical fire regime, with alluvial-sediments biased towards infrequent, high-severity events during recent millennia, and the tree-ring record biased toward lower severity fires during recent centuries. The combined analyses of different paleofire proxy types in the same study sites, therefore, can enhance and expand our understanding of fire and climate history beyond what is possible with either proxy alone.

No description available.

A decision to recall products by firms can lead to negative consequences such as erosion of shareholder wealth and loss of customer goodwill. Further, the way a recall is managed can lead to more negative consequences than the recall decision itself. Therefore the manner in which firms manage such decisions can help mitigate these negative consequences. This thesis examines two such decisions: recall restitution and time to recall. A firm’s decisions on restitution offered to affected customers and time to recall may evoke conflicting reactions from shareholders and customers, where serving the interests of one stakeholder affects the interests of the other. While higher restitutions and faster recalls improve customer goodwill, they lead to erosion of shareholder wealth. This finding is used to hypothesize the influence of organizational characteristics (position of the firm in the value chain, firm’s internal operations, and firm’s recall experience), and key crisis factors (ambiguity and severity) on these decisions. This thesis uses data on toy recalls issued in the U.S. from 1988 to 2011. The results show that firms tend to favor shareholders by offering lower restitutions to affected customers when they are situated farther from the customer in the supply chain, when they have more experience with recalls, when the crisis is severe, and when the cause of the crisis is ambiguous. When the recall is due to the internal operations of the firm, restitution offered to affected customers is lower only when the severity of the recall is high. Firms issue recalls quickly when the crisis is severe in order to reduce customer hazards and avoid negative publicity. Severe recalls, however, may be delayed when firms are experienced in recall management, and when such recalls are caused by the internal operations of the firm. The findings of this thesis highlight one of the dilemmas that firms face in a crisis decision making situation and help foster an understanding of the conditions under which firms manage shareholder versus customer reactions in order to mitigate the negative consequences of recall management decisions.

This study investigated whether or not variability in the severity of speech sound disorders is related to variability in phonological short-term memory and/or variability in the accuracy of phonological representations. The aim was to determine speech processing predictors of severity of speech sound disorders. A total of 33 children, aged three to six years of age, were assessed on measures of nonword repetition, accuracy of phonological representations, accuracy of speech production, and language. The tests administered included the Clinical Evaluation of Language Fundamentals Preschool – 2 Australian, the Diagnostic Evaluation of Articulation and Phonology, the Nonword Repetition Test (modified), and the Phonological Representation Judgement Task (modified). The relationships between the results of these tests were established using a correlation analysis. The relationship between accuracy of phonological representations and the percentage of consonants correct was found to be mediated by language. There was no significant relationship between nonword repetition and percentage consonants correct. These findings may have been the result of small sample size, age of the participants, or co-morbid language difficulties. These findings imply that variability in severity of speech sound disorders may be related to a variable not directly assessed in this study. This variable may be a constraint relating to the stored motor programs within children’s speech processing systems. Implications for future research are discussed.

The aim of the present doctoral thesis was to investigate the ability of patients with Alzheimer's disease (AD) to utilize cognitive support in order to improve episodic remembering. A review of previous research indicated that most studies have failed to find beneficial effects of encoding support on memory in AD patients. The ability to utilize cognitive support (i.e., motoric activities, semantic organization, and semantic knowledge) for episodic remembering was investigated in five studies (Bäckman &amp; Herlitz, 1990; Herlitz, Adolfsson, Bäckman, &amp; Nilsson, in press; Herlitz &amp; Bäckman, 1990; Herlitz &amp; Viitanen, in press; Karlsson et al., 1989). Patients with mild, moderate, or severe AD, and normal older adults participated in the studies. On the basis of the results from these studies and the review of the literature, it was concluded that (a) AD patients, irrespective of dementia severity, perform at a lower level than normal older adults in episodic memory tasks; (b) provided that support is supplied at retrieval, AD patients may be sensitive to manipulations at encoding; (c) the strength of the encoding manipulation determines the size of the memory improvement in AD patients; and (d) depending on dementia severity, the type of encoding support also determines the magnitude of memory improvement obtained. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1991, härtill 5 uppsatser.</p> / digitalisering@umu

Objectif: Le syndrome d'apnée obstructive du sommeil (SAOS) est de plus en plus présent en Amérique du Nord et a été associé avec certaines maladies chroniques, particulièrement les maladies cardiaques. En première ligne, là où la prévalence de cooccurrence de maladies chroniques est très élevée, l'association potentielle avec l'apnée du sommeil est inconnue. L'objectif de cette étude était d'explorer l'association entre l'apnée obstructive du sommeil et 1) la présence et la gravité de la multimorbidité (cooccurrence de plusieurs maladies chroniques), et 2) des sous-catégories de multimorbidité. Méthode La technique d'échantillonnage en grappe a été utilisée pour recruter 120 patients atteints de SAOS à différents niveaux de gravité et ce, à partir de la base de données d'un laboratoire de sommeil. La gravité de la maladie a été établie grâce aux résultats de la polysomnographie. Les patients, qui furent invités à participer, ont reçu, par la poste, un questionnaire de renseignements sociodémographiques et le questionnaire auto-rapporté Disease Burden Morbidity Assessment (DBMA). L'envoi incluait un formulaire de consentement permettant l'accès au dossier médical afin d'obtenir plusieurs autres informations essentielles. Le DBMA a été utilisé pour avoir un score global de multimorbidité et des sous-scores de maladies qui affectent divers systèmes. Résultats Les analyses bivariées n'ont pas permis de démontrer une association entre l'apnée obstructive du sommeil et la multimorbidité (r = 0,117; p = 0,205). Par contre, le SAOS grave a été associé à la multimorbidité (odds ratio ajustés = 7,3 [1,7-32,2] ; p = 0,05). Le SAOS est modérément corrélé avec des sous-scores de multimorbidité vasculaire (r = 0,26 ; p = 0,01) et de syndrome métabolique (r = 0,26 ; p = 0,01). Conclusion Cette étude démontre que la gravité du SAOS est associée à la gravité de la multimorbidité et à des sous-scores de multimorbidité. Cette recherche ne permet pas d'établir un lien de causalité, d'autres recherches s'imposent pour confirmer ces associations. Toutefois, les intervenants de santé en première ligne devraient être au fait de cette association potentielle et devraient investiguer la présence de l'apnée du sommeil quand cela leur semble approprié.