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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Skogsmyror (Formica rufa-gruppen) i monokulturell granskog och i nyckelbiotoper med hög andel gran i södra Sverige

Petersson, Germund January 2019 (has links)
Ants belonging to the Formica rufa group (wood ants) and their mounds have a large impact on forest ecosystems. This makes them considered keystone species. Several species of wood ants are threatened globally according to the IUCN red list. In this degree project mound densities and mound volumes were evaluated and compared between Norway spruce monocultures and high part Norway spruce woodland key habitats (WKHs) in southern Sweden. There were no significant differences in neihter mound densities nor mound volumes between the two stand types. However, mounds were distributed differently within the stand types and tree density correlated negatively to mound density in both stand types. Wood ant mounds were absent in the interior of monoculture stands, except in light gaps, while several mounds where located in the interior of WKHs. My results suggest that there is not enough light in the interior of monocultures in southern Sweden for wood ants to be able to colonize. Large monoculture areas may lack wood ants if gaps are missing. Therefore, gaps inside monocultures should be made more common in Swedish forests in order to benefit wood ants in production forests. Small clearcuts seem to benefit wood ant dispersal in monocultural stands. Therefore, smaller clearcuts should be preferred over the large areas presently clearcutted due to the negative effects of large clearcuts on wood ants.
202

The limits of species recognition: heterospecific song learning in pied flycatchers

Triantafyllidou, Maria January 2016 (has links)
The closely related species pied flycatcher (Ficedula hypoleuca) and collared flycatcher (F. albicollis) co-occur on the Swedish island of Öland, where they compete over similar resources. The majority of male pied flycatchers have been found to incorporate elements of the collared flycatcher song in their repertoire. Given that birdsong is partly inherited and partly learned, the relative contribution of genetic predispositions versus acoustic stimuli varies across different species. The results show that in pied flycatchers, song acquisition is tightly correlated with imprinting, and can therefore be greatly influenced by heterospecific tutors in their surroundings, i.e. male collared flycatchers. I found that pied males are capable of not only memorizing collared song elements, but also producing them with high fidelity. Thus, I infer that pied flycatchers are characterized by a high degree of vocal plasticity.
203

Population dynamics and management strategies of stray and free-ranging dogs in Bor, Serbia

Skrijelj, Lejla January 2019 (has links)
Dogs are one of the most widespread carnivore and the third most invasive mammal, after cats and rodents. Stray dogs affect wildlife negatively by predation, disturbance, disease spreading, competition and hybridization with other wild canids. Even in urban environments stray dogs cause problems such as disturbance, pollution, traffic accidents, bites and risk of disease spreading. Serbia is one of many countries in the Balkan region that has a problem with overpopulation of stray dogs. The aim of this study is to investigate the population dynamics of stray dogs in Bor, Serbia and discuss different dog population management strategies. A total of 361 stray dogs were registered, 111 male dogs, 85 female dogs and 165 dogs with undetermined sex. 55 dogs (15.23%) were estimated to be older than 7 years old, 262 dogs (72.57%) were estimated to be between 3-7 years old, 30 dogs (8.31%) were estimated to be between 6-24 months old and 14 dogs (3.87) were estimated to be between 0-6 months old. No dogs showed any signs of rabies or CDV (canine distemper virus) and 241 stray dogs (66.75%) seemed healthy. 120 stray dogs (33.25%) did however have some kind of impaired health. To achieve a stop in the population increase,70% sterilisation rate is required and to teach responsible dog ownership. The stray dogs showed different reactions towards people, 164 dogs (45.42%) were neutral and 100 dogs (27.70%) showed no fear or aggression towards humans and gladly interacted. Since the dogs are highly accessible, they would be acceptable for a TNR (trap-neuter-release) program and male dogs need to be prioritised considering their dispersal patterns. / Hundar är en av de mest spridda karnivorerna och det tredje mest invasiva däggdjuret, efter katter och gnagare. Gatuhundar påverkar vilda djur negativt genom predation, störning, spridning av sjukdomar, konkurrens och hybridisering med andra vilda hunddjur. Även i urbana miljöer har gatuhundar en negativ påverkan, genom störning, förorening, trafikolyckor, bett och sjukdomsrisk. Serbien är ett av många länder i Balkanregionen som har för stora populationer av gatuhundar. I detta arbete undersöks populationsdynamiken hos gatuhundar i Bor, Serbien och diskuterar olika metoder för att hantera gatuhundpopulationen. Totalt inventerades 361 gatuhundar, 111 hanar, 85 honor och 165 med obestämt kön. 55 hundar (15.23%) uppskattades vara äldre än 7 år, 262 hundar (72.57%) uppskattades vara mellan 3-7 år, 30 hundar (8.31%) uppskattades vara mellan 6-24 månader gamla och 14 hundar (3.87) uppskattades vara mellan 0-6 månader gamla. Inga hundar visade tecken på rabies eller CDV (canine distemper virus) och 241 gatuhundar (66.75%) föreföll friska. Däremot visade 120 hundar (33.25%) någon typ av nedsatt hälsa. För att uppnå ett stopp i populationsökningen krävs minst 70% steriliseringstakt samt att man lär ut ansvarsfullt hundägande. Gatuhundarna visade olika reaktioner mot människor, 164 hundar (45.42%) var neutrala och 100 hundar (27.70%) visade ingen rädsla eller aggression för människor och interagerade gärna. Eftersom gatuhundarna är lättillgängliga, skulle de kunna ingå i populationshanteringar som TNR (trap-neuter-release) och hanhundar bör prioriteras med tanke på deras spridningsmönster.
204

The Physiological Effects of Long-term Unemployment

Andersson, Maja January 2019 (has links)
The stress system is essential for humans and other organisms to survive. However, when stress is prolonged it can have pathological effects on the brain. To experience long-term unemployment is often stressful, for it has been shown to correlate with depression, low self- esteem, learned helplessness and self-destructive behavior. Long-term unemployment also seems to have physiological consequences, for it has been shown to correlate with cortisol dysregulation. The hippocampus is a highly adaptable part of the brain located in the temporal lobe and is long known for its sensitivity to cortisol dysregulation due to stress. The aim of this thesis is to study how long-term unemployment affects physical and psychological well- being, focusing in particular upon finding out whether it affects the hippocampus. The results suggest that that the kind of stress caused by long-term unemployment is similar to the stress affecting the hippocampus. It thus seems to be a reasonably hypothesis that long-term unemployment has a negative influence upon the brain, and the hippocampus in particular.However, there is an additional issue that one needs to take into account. For some studies have shown that people with poor mental health are more likely to be unemployed. If poor mental health is associated with physiological disorders (including a damaged hippocampus), this implies that not only can long-term unemployment (via stress) affect the hippocampus, but a damaged hippocampus (along with other physiological factors) can increase the probability to become unemployed. This means that the relationship between long-term unemployment and a damaged hippocampus need not be a one-way causal relationship.
205

Think your pain away : The neurochemistry of placebo analgesia

Alteryd, Olivia January 2019 (has links)
Placebo treatments are inert but are known to alleviate symptoms across numerous clinical conditions. One of the most studied placebo effects is placebo analgesia, which is a placebo effect limited to pain relief. This thesis aims to introduce the current state of research regarding the neuroscience of placebo analgesia and specifically to present research findings regarding the neurotransmission. Studies have demonstrated that placebo analgesia can be elicited through two separate processes interacting with each other; manipulation of expectations and through conditioning. These processes seem to affect neurotransmission in different ways. Many brain areas have been found to be correlated to placebo analgesia. Besides the pain-processing brain areas, studies point to that the prefrontal cortex can have a vital role in the placebo analgesic effect. Known neurotransmitters that have shown to be involved in placebo analgesia are endogenous opioids, cholecystokinin (CCK), and endocannabinoids. Studies point to that endogenous opioids are involved in the placebo analgesic effect when elicited by expectation or conditioned by an opioid drug. CCK act on placebo analgesia by affecting the release of endogenous opioids and endocannabinoids seem to be involved in placebo analgesia while it occurs due to conditioning with non-opioid drugs. Getting a better understanding of placebo analgesia and find ways to apply this knowledge in the clinical context could powerfully develop the whole medical society.
206

The mechanisms of addiction and impairments related to drug use

Eeli, Emelie January 2018 (has links)
This thesis contains an overview of the mechanisms of addiction as well as a description of the impairments related to drug abuse. The general view of addiction is that it depends on three characteristics that have separate neural mechanisms, called “wanting”, liking and learning. “Wanting” is described as a desire evoked by reward cues, liking refers to the pleasure of getting a reward and learning is described in terms of classical conditioning. “Wanting” and liking are usually in agreement but in addiction they are dissociable, that is, wanting a drug but getting no pleasure from it. Reward cues, acquired through learning, awakes the motivation to obtain the drug again. This can be problematic when trying to cease drug taking. The dopamine system in the brain is much discussed in relation to addiction and its neural correlates. The prefrontal cortex (PFC) is suggested to be altered in addiction, and this may underlie some of the impairments discussed. Addiction is also strongly related to cognitive impairments such as working memory problems, impulsivity, attentional problems and decision-making impairments. Affective impairments, such as empathy problems, may also to have some connection to addiction, although this is less clear.
207

Vägtrafikbuller utefter E6 Tanumshede och dess effekt på fågelfaunan / Does road noise from E6 in Tanumshede and the effects on birds abundance and species composition?

Risberg, Ronja January 2018 (has links)
Studier har visat att fåglar påverkas av ökade ljudnivåer och ljudfrekvenser (Kociolek et. Al. 2011). Olika fågelarter skiljer sig i känslighet vid störning av ljud. Vissa arter kan anpassa sig och förändra sin kommunikation till den nya ljudsituationen. Andra kan påverkas i sin fortplantning då lätet är en väsentlig del av partnerkommunikationen. Vidare kan vissa fågelarter behöva flytta till ett annat habitat på grund av att de inte kunnat anpassa sig (Gill et. Al. 1999, Helldin 2004). Fågelinventeringar för nybyggnation av motorväg E6 Tanumshede, Norra Bohuslän redovisar antalet fåglar innan och efter motorvägens öppnande den 7 juli 2015. Hypotesen att ljudnivåer skiljer sig i nivå med avstånd från motorvägen och jämfört med referensskog bekräftades. Däremot visar analyser med en ANOVA inte på att antalet fåglar är påverkat av en högre ljudnivå. En del fågelarter uppvisar en signifikant ökning eller minskning i antal, vid analys av dessa fåglars kommunikationsfrekvenser kunde ingen signifikant skillnad ses. Det har inte funnits tillräckligt underlag för att göra en bedömning av mer sällsynta arter som eventuellt skulle vara mer påverkade av en förändrad ljudbild. / Studies have shown that birds are affected by increased noise levels and changes in sound frequencies (Kociolek et al. 2011). Different bird species differ in their sensitivity to noise disturbance. Some species can adapt and change their communication to the new sound situation, whereas others may be affected in their reproduction because sound in an essential part of partner communication. Furthermore, some species may need to move to another habitat because they could not adapt to the new sound situation (Gill et al. 1999, Helldin 2004). Birds inventories for the new motorway construction, E6 Tanumshede North Bohuslän, report the numbers and species of birds before and after the opening of the motorway on July 7, 2015. The hypothesis that noise levels differ at the distance from the highway and compared to reference forests were confirmed. On the other hand, analyses with an ANOVA do not indicate that the number of birds is affected by a higher noise level. Some bird species showed a significant increase in numbers after roadwork, whereas others decreased. No significant difference could be seen in the analysis of these birds’ communication sound frequencies. There has been insufficient support to make an assessment of more rare species that might be more affected by a changing noise levels.
208

Dissolved organic carbon (DOC) : Differences in reactivity amongst water sources to boreal streams in Sweden

Eriksson, Lukas January 2018 (has links)
The importance of dissolved organic carbon (DOC) to aquatic environments is well established in the scientific community. In boreal landscapes, small streams receive water from headwater lakes, mires, and discrete flow paths that drain riparian soils. The goal of this study was to investigate the importance of these discrete riparian inputs (DRIPs) as sources of DOC and to explore whether quantity and quality of DOC from DRIPs differs from other sources in the landscape, including groundwaters that are not as hydrologically connected to streams. To do this, I collected water from already established riparian groundwater wells installed at the Krycklan Catchment Study (KCS) in northern Sweden, as well as from an adjacent lake, stream, and mire. Microbial activity (respiration) was analyzed in 24-hour laboratory incubations using a metabolically active dye, resazurin (Raz) which in the presence of aerobic respiration transforms into resorufin (Rru). Rru is easily measured in the lab, and its production can serve as a proxy for rates of microbial respiration. DOC concentration was also measured at each location, along with specific absorbance at 254 nm (SUVA254) and the absorbance ratio (254/365 nm) as indices of DOC quality. The results show a large variation in DOC concentration among potential water sources to the stream. Furthermore, there was a strong correlation (R2=0.96) between Rru production and DOC concentration among these sources, but no significant difference (p=0.067) in median Rru production between DRIPs and non-DRIPs. Overall, these results highlight important spatial variability in DOC from different water sources in the landscape, which likely have important consequences for patterns of microbial respiration in streams.
209

Humlors (Bombus spp.) möjlighet till fortlevnad utmed vägkanter intill cykelleder i Halmstad med omnejd

Svensson, Emma January 2018 (has links)
There is an ongoing negative trend on pollinator abundance worldwide due to different threats that affect their health and living conditions, such as pathogens and parasites in combination with different types of habitat loss among other factors. In this study I investigate if road verges adjacent to cycle paths could be a suitable environment for bumblebees (Bombus spp.) to thrive. 13 sites were sampled to find out what kind of diversity of bumblebees and flowering plants this type of habitat could hold by observing different aspects, e.g. shade and vegetation coverage together with species diversity and abundance. The results showed that shade coverage had an effect on the flower diversity at the sites and also that bumblebee species diversity as well as bumblebee abundance got affected by the diversity of flowers.
210

Förbrukningsmaterial i det pedagogiska arbetet inom förskolan : om hur förskollärare kopplar materialanvändning till miljöfrågor / How preschool teachers link the use of consumables to environmental issues

Drugge, Anna January 2018 (has links)
The purpose of this paper was to study if, and in what way, usage of consumables is part of preschool teachers' pedagogical work with the children concerning environmental issues. The study was done through qualitative interviews with six certified preschool teachers from five different preschools, all located in a mid-sized town in Sweden. Results from the study show that there are existing routines concerning the childrens' usage of consumables, and that the preschools environmental work could be connected to them. There were routines before, during and after the creating process. The most common consumables at the preschool was paper and pearls. In order to save resources and the environment, the preschool teachers had guidelines on how to use these consumables. Areas of use for the consumables could vary depending on age, development and level of challenge with the specific child. The preschool teachers in the study assured that they tried to accomodate needs and interests with each individual child and thereby finding areas for development and challenge. The teachers saw the work with resources from both an environmental and a pedagogical view and considered them both an integral part in the work for the childrens development and learning. How the staff viewed environmental issues in relation to consumables was also an important indication as to how environmental issues where reflected as a whole in the school. Also, the teachers considered the work with environmental issues as something that sometimes happens subconsciously since it is such an obvious part of the job. / Syftet med denna studie var att belysa om och på vilka olika sätt förskollärare kopplar användningen av förbrukningsmaterial till miljöfrågor i det pedagogiska arbetet med barnen. Undersökningen har genomförts via kvalitativa intervjuer med sex stycken legitimerade förskollärare, på fem olika kommunala förskolor i en stad i mellersta Sverige. Resultatet visar att det fanns rutiner kring barns hantering och användning av förbrukningsmaterial på förskolan som kunde kopplas till förskolans miljöarbete. Det fanns rutiner både före, under och efter själva skapandet. Papper och pärlor var de förbrukningsmaterial som konsumerades mest på förskolan. Därför hade förskollärarna riktlinjer hur dessa material skulle användas, för att spara in på resurserna och miljön. Användningsområdena kunde däremot variera beroende på barnens ålder, utveckling och utmaningsgrad. Förskollärarna i studien menade att de försökte bemöta barnens intressen och behov och därmed hitta utvecklingsmöjligheter och utmaningar för varje enskild individ. Förskollärarna såg arbetet med resurser ur både en miljöaspekt och pedagogisk aspekt och menade att dessa går hand i hand i verksamheten för barnens utveckling och lärande. Resultatet visade även att förskollärarnas förhållningsätt till miljö kopplat till förbrukningsmaterial spelar en viktig roll, för på vilket sätt övriga miljöfrågor reflekterades i verksamheten. Samtidigt menar förskollärarna att arbeta med miljöfrågor är en del av uppdraget och sker ibland omedvetet.

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