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93 Uppsatser om Climatic gradient - Sida 1 av 7
Sänkta sjöars inverkan på ytvatten i Västerbottens kustland : Samband mellan sänkningsnivåer och vattenkemi i sjöar på sulfidrika sedimentjordar
Lake lowering in sulphide-rich areas is currently a major environmental impact for surface water. This study focuses on whether there is a relationship between a gradient of lake lowering and surface water impacts in areas of sulphide-rich sediments, in order to better understand their contribution of heavy metals and sulfuric acid. Also, is it a reasonable method to use the reduced lake area in order to quantify the gradient? The survey was conducted by collecting water samples from reference lakes and lowered lakes from south to north in coastal areas within the county of Västerbotten. Water samples were then analyzed for TOC, pH, conductivity, anions, base cations, alkalinity, acidity, sulfate, Al, Cd, Fe, Mn, Cu, Zn and Pb.
Tid kontra pengar : Goal-gradient effekt vid valet mellan nettonuvärdesmetoden och återbetalningsregeln
Syftet med denna uppsats var att studera om det finns en målgradient vid investeringsbedömning som medför en preferens för alternativ med kort återbetalningstid och snabba belöningar. Vi valde att genomföra denna studie med hjälp av en kvantitativ ansats, då vi genomförde ett experiment med studenter vid Blekinge Tekniska Högskola. Detta motiverar vi med att utifrån vårt syfte och vår teoretiska referensram, ger det oss störst möjlighet att generera ett intressant och relevant resultat. Vårt resultat visar tydligt att beslutsfattare föredrar att använda återbetalningsregeln före nettonuvärdesmetoden i en beslutssituation, och därmed ett fokus på tidsaspekten och när en investering är återbetald. 81 % av våra respondenter valde tidsalternativet i minst ett av de två casen.
Variation in protein precipitation and phenolic content within and among species across an elevational gradient in subarctic Sweden
This project investigated how elevation and vegetation type influences variation in plant litter phenolic content and protein precipitation capacity among and within common plant species for two different vegetation types, heath and meadow, in a subarctic ecosystem in the Abisko region of northern Sweden. As nutrient availability generally decreases with increasing elevation as a result of decreasing temperature, I hypothesised that phenolic content would increase with elevation and be higher on the heath than the meadow. To test this, the total phenolic content and protein precipitation capacity was estimated in leaf litter from 13 species in both heath and meadow vegetation across an elevational gradient ranging from 500 to 1000 meters above sea level (m.a.s.l.) in the study region. The results showed that elevation and vegetation type both had a strong impact on both variables. Total phenolic concentrations decreased with elevation for the meadow, and were greater for the heath than the meadow.
Sjöars känslighet för klimatförändringar ? vilka faktorer påverkar?
The Earths climate is changing at a higher rate, i.e between 1861 and 1994 the annual mean temperature in Scandinavia increased with 0,68º C and according to recent climate models the annual mean temperature is likely to rise with another 3º C during this century.A warmer climate in many ways is associated with changing conditions for lake ecosystems. An expected higher water temperature and a stronger summer stratification of the water column increases the risk of anoxic conditions at the lake bottom. Thus anoxic conditions are likely to cause a phosphate leakage from the sediment, i.e. a higher internal loading of phosphate.In this project, the extremely warm summer of 2002 has been used as an example for a possible scenario for a future climate. By comparing levels of phosphorus in the summer of 2002 with a ten-year median value, a phosphorus related sensitivity to climate change has been analyzed for 55 Swedish lakes.
Elementkoncentrationer i gran utmed en markfuktighetsgradient :
One key factor in silviculture today is sustainability. In order to achieve sustainability it may be important to restore lost nutrients to the forest after clearcutting. In order to calculate the removal, you need to know how much of different elements you will find in different tree compartments. The aim of this study was to investigate if the concentration of elements in different tree compartments of spruce (Picea abies (L.) Karst) were related to the moisture conditions of the site. Five plots at Risfallet (60º 21´ N, 16º 13´ E), was placed along a moisture gradient in a 40- year spruce stand.
Blå vägens glasbjörkar : från groning till allé
Det här projektet består av en litteraturstudie på trädformig björk (Betula) i Sverige, samt en studie av glasbjörk (B. pubescens) längs en klimatgradient genom Norra Sverige och Norge. Längs den studerade gradienten skiljer sig vegetationsperiodens längd med över en månad i den kallaste delen av gradienten jämfört med den varmaste. Frön längs gradienten har studerats med avseende på grobarhet före och efter simulerad invintring i syfte att undersöka om det finns trender i grad av frövila och grobarhet längs gradienten. Den simulerade invintringen hade en positiv effekt både på groningshastighet och på andel frön som grodde.
Vägparametrar och deras inverkan på trafiksäkerheten : Fallstudie på länsväg 360 Lycksele - Vilhelmina
The interaction between the driver, the car and the road is essential for the road safety. This case study focuses on the road condition and its effect regarding road safety issues. By studying and isolating the road condition aspect and its contributing role to the accident occurrence, the aim is to explore their relationship, as well as highlight the road parameters that are commonly associated with accident occurrence. This result will be used to develop and increase awareness of the impact of poor road alignment and poor road surface conditions on traffic safety, in order to prevent these accidents from occurring. The road parameters chosen for this study include side friction, cross slope and rut bottom cross slope, road texture, curvature, drainage gradient and rutting.The case study was limited to lv 360 in Va?sterbotten, where all accidents with an unclear cause of the accident were studied, between 2003 and 2012 were carefully studied and assessed based on the condition of the road at the time of the accident.
Tid kontra pengar - Goal-gradient effekt vid valet mellan nettonuvärdesmetoden och återbetalningsregeln
Syftet med denna uppsats var att studera om det finns en målgradient vid
investeringsbedömning som medför en preferens för alternativ med kort
återbetalningstid och snabba belöningar.
Vi valde att genomföra denna studie med hjälp av en kvantitativ ansats, då vi
genomförde ett experiment med studenter vid Blekinge Tekniska Högskola. Detta
motiverar vi med att utifrån vårt syfte och vår teoretiska referensram, ger det
oss störst möjlighet att generera ett intressant och relevant resultat.
Vårt resultat visar tydligt att beslutsfattare föredrar att använda
återbetalningsregeln före nettonuvärdesmetoden i en beslutssituation, och
därmed ett fokus på tidsaspekten och när en investering är återbetald. 81 % av
våra respondenter valde tidsalternativet i minst ett av de två casen.
Axial- och gradientkrympning hos golv på mark enligt Eurokod 2 : Sprickbredders beroende av betongkvalité, tvångseffekter och armeringshalt
AbstractConcrete foundation slabs are usually exposed to unilateral drying during the curing process. The unilateral drying causes an axial shrinkage and a concave curvature of the construction. The curvature results from the fact that the upper part of the slab is drying and shrinking faster than the lower part. This is called gradient shrinkage.A problem occurs when the slab is considered fully restrained by adjoining structural parts. The deformations caused by axial contraction due to the constant part of the shrinkage and the curvature caused by gradient shrinkage of the slab are then prevented by the fact that the slab is fully restrained.
Kromatinstabilitet som grund för kvalitetsbedömning av hingstsperma :
This study is part of a project to evaluate and develop metods to control the semen quality in stallions. The study was carried out in cooperation between SLU and Flyinge AB. The objective of the study was to analyse
-if there are individual differences in sperm chromatin integrety between different stallions
-if there is a correlation between subjectively evaluated sperm motility and sperm chromatin integrity
-if sperm chromatin integrity is changed after selection of the semen with a centrifugation method through the silica-spheres, gradient or a single-layer, i.e to use the chromatin integrity analysis as a method to evaluate the selection method.
The use of chilled transported semen has increased a lot during the last 10 years, especially among the Swedish warmblood breed. Because the foaling percentage has decreased with the increased use of chilled transported semen, there is a need to develop methods to control the sperm quality. Evaluation of the chromatin integrity could be one way to evaluate the quality of the semen.
Chromatin is the DNA in the nucleus of the sperm.
Utveckling av provmetodik för HVAC på lastbil : Klimatprovning i klimatvindtunneln CD7
The issue about how Scania shall perform HVAC tests in the climatic wind tunnel CD7, which Scania is about to complete by year 2013, has resulted in four test methods for truck HVAC and also a test method structure. The test methods have been chosen to focus on sun, snow and rain simulations. These are adapted and developed according to what should be tested and to what can be tested in CD7, which has been the object. With CD7 different climates can be simulated in a controlled environment for complete truck level, from desert with high sun load to arctic cold and snow.The test methods represents a basis to start from, for designers and test engineers which make the testing more repetitive as well as time eventually can be saved. Before the test methods can be applied they must be verified as they are based on theoretical and empirical assumptions.
Tillväxt hos Husmossa (Hylocomium splendens) i boreal skog och växthus : effekter av ökad vattentillgång
Hylocomium splendens (Glittering wood-moss) is a common species in the Nordic countries and can be found in many different types of boreal forests. It usually forms dense moss carpets on the forest floor. The shoots grow in segments and new segments form annually on the previous years growth. The size of the segments is probably regulated in a high extent by local micro environmental conditions. Previous experiments suggest increased growth of H.
Små skogliga vattendrag i Värmland - Generell beskrivning, förekomst av traktorspår samt spårens inverkan på bottenfaunan :
Modern forestry requires a high degree of machine traffic for clear felling and scarification operations. The machines most frequently used are big and the traffic often results in tracks on the forest ground. There are many small streams running through a forest, in connection to logging operations, machines might cross these frequently. These crossings could result in the erosion of fine particulate inorganic matter, which ends up in the stream. The aim of this thesis was to give a general description of small forest streams of order-one in the county of Värmland and to determine the frequency of machine tracks in small streams.
Bokhögstubbar i Klåveröds strövområde : utbredning, egenskaper och betydelse för rödlistade vedlevande skalbaggar
Lack of dead wood is the main cause of decaying or loss of populations for many
forest species. To increase the amount of dead wood is a prerequisite to maintain
biodiversity in forests of northern Europe. In summer 2006 the recreation area
Klåveröd, at Söderåsen in Skåne, Sweden, has been inventoried for high stumps
(snags) of beech, (Fagus sylvatica). The result of the inventory has been compared
with data of the real estate and forest management directories from the owner,
region Skåne. The results have also been matched with the results from an
inventory of saproxylic beetles in 2005, performed with windowtraps on selected
snags both in the area and the adjacent national park Söderåsen.
594 snags were found on 747 ha.
Strömmar av vatten och politik - en studie om policyprocesser och anpassning.
One of the distinguishing features of successful societies is the ability to adapt to change, bothsocial but also natural changes like climate change. Climate change is a complex, dynamic,non-linear process with a great deal of uncertainty concerning the time perspective, risks andconsequences. A combination of factors like climate change, geographical vulnerability, adensely populated and highly built up coast line along with factors like deficient handling ofsurface runoff and a large usage of ground water leads to an increasingly vulnerable society. Italso puts a greater pressure on the society to have preventive measures in place.The number of actors working with preparing society to the expected impacts of climatechange and variability is increasing. However more than half of Sweden?s municipalities donot consider changing climatic conditions when planning, and many times even allow theconstruction of new living areas in known climatically vulnerable areas.