Göteborgs universitets publikationer - e-publicering och e-arkiv
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BARK AND FOLIAR WATER UPTAKE CAPACITY OF TROPICAL TREE SPECIES IN RWANDA
No full textWater is essential for tree function and survival, yet climate warming poses increasing
threats to tree health, particularly in tropical regions where droughts are intensifying.
While foliar water uptake (FWU) and bark water uptake (BWU), described as the direct
uptake of water through leaf and bark surfaces, are increasingly recognized as
important supplementary water sources, both processes remain understudied—
especially in tropical forests. Here, we investigate species- and climate-related
variation in foliar and bark water uptake capacity in 11 tropical tree species (8 for BWU)
growing along an elevational gradient in Rwanda. All trees were subjected to a
standardized wetting treatment, where stems segments and leaves were fully
submerged in water for two hours under controlled conditions. Ten species
demonstrated the capacity to absorb water through foliage and all eight species
through bark, with substantial interspecific variation. In addition, we examined the
influence of a range of physical traits on water uptake. The ability to retain water on
surfaces—especially via trichomes on leaves and rough bark on stems—emerged as
key factors influencing bark and foliar water uptake. This is the first study, to our
knowledge, to assess bark and foliar water uptake in African trees as well as
simultaneously on the same individual plants, offering novel insights into the role of
external water uptake in tropical tree ecophysiology
EFFECTS OF ANTIBIOTICS AND MULTIDRUG RESISTANT E. COLI ON BACTERIAL SEDIMENT COMMUNITIES
No full textThe spread of antibiotic resistance is a global health concern, with growing evidence that
environmental reservoirs such as aquatic sediments play a role in antibiotic resistance
persistence and dissemination. This study investigates the effects of a mixture of antibiotics
and the establishment of a multidrug-resistant strain of Escherichia coli at levels commonly
discharged by wastewater treatments plants on freshwater sediment bacterial communities.
In addition, the study evaluates how the potential E. coli establishment was affected by the
occurrence of antibiotics. To assess the effect and interaction of these two variables, a 10-day
static test was performed in microcosm conditions using sediment from Lake Vänern,
Sweden. Prior to the full experiment, a pilot study was performed to assess the invasion
capacity of E. coli on sediment and how to prepare the inoculation of E.coli in the sediment.
Results from the pilot study demonstrated that E.coli was able to survive and establish in the
sediment for up to 28 days. In the full experiment an increase of the blaCTX-M gene in the
sediment invaded by E.coli was observed after 1, 3, and 7 days after inoculation, indicating
potential resistance spread to natural bacterial communities. The occurrence of antibiotic
contamination positively affected the spread of antibiotic resistance genes (ARGs) on natural
communities. The functions of the community were resilient to both the exposed antibiotic
mixture and the invasion of the E.coli, attributed to functional redundancy in the bacteria
communities and no-ecological effects of acquiring ARGs. The bacterial communities appear
to have a higher carbon metabolism and a higher nitrification over time, attributed to an
increasement on their efficiencies in using carbon and ammonium.
These findings underscore the potential of invading bacteria carrying ARGs, such as E.coli, to
influence the resistome of bacterial communities, and how this is modulated by the
occurrence of antibiotic contamination. This study highlights the importance of incorporating
environmental dimensions into antibiotic resistance research and supports a One Health
approach to managing antimicrobial resistance
Spatial Contextualization of Heat Mitigation and Recreational Aspects of Greenery in Various Urban Environments
No full textUrban greenery has significant potential to provide heat mitigating and recreational functions for urban residents. However, the ability of greenery to deliver these benefits is highly dependent on its spatial context. The aim of this thesis is to examine how greenery—and its heat-mitigating and recreational functions and benefits—is spatially distributed in residential and everyday environments. It also seeks to develop methods to assess and compare the functions that different types of greenery can offer, depending on spatial context and planning needs.
The first two papers show that access to greenery in residential environments varies across housing typologies, resulting in unequal access to its recreational benefits. They also highlight that greenery, particularly trees, plays a crucial role in reducing heat stress in preschool yards—many of which currently lack sufficient shade—as well as in providing recreational benefits in
residential areas. The third paper demonstrates that the cooling potential of trees is strongly influenced by surrounding ground conditions. Trees growing in areas with a higher proportion of permeable surfaces can grow larger, transpire more, and provide more effective shade, thereby enhancing their cooling effect. The final two papers contribute methods for assessing the multifunctionality of greenery and for better integrating spatial context into urban planning and analysis. The results show that the
unctional and multifunctional potential of different green elements varies, with generally low overall multifunctionality. Thus, while multifunctionality is a desirable goal, specific functions may need to be prioritised in certain contexts to meet local needs. The findings also emphasise the importance of proper parametrisation of urban climate models to accurately reflect local conditions within the model domain.
In summary, this thesis emphasises the importance of considering spatial context in the study and planning of urban greenery. It contributes new knowledge on the variation in functions and benefits of greenery in everyday environments and offers practical
tools to support planners and decision makers in more effectively integrating greenery into urban development, adapted to spatial context and local need
The Population Crisis in Sub-Saharan Africa: Biodiversity Threats and Swedish Foreign Aid Perceptions
No full textDen globala befolkningskrisen är underrepresenterad i offentlig debatt, trots dess kritiska inverkan på biologisk mångfald och hållbar utveckling. Befolkningstillväxten intensifierar miljöutmaningar som förlust av livsmiljöer, exploatering av resurser och utsläpp av växthusgaser. Denna uppsats undersöker 1) förhållandet mellan mänsklig befolkningstäthet och hotet mot vilda arter i länder i Afrika söder om Sahara, som nästan alla står inför hög befolkningstillväxt, och 2) offentligt stöd till familjeplanering i internationellt bistånd till Afrika från givarlandet Sverige. Korrelationsanalyser med data från IUCN:s rödlista och populationsdata från Världsbanken visar ett positivt samband mellan mänsklig befolkningstäthet och hot mot arter i följande taxonomiska grupper: alla bedömda sårbara, hotade och akut hotade arter, djur (Animalia), växter (Plantae), primater och fåglar tillsammans, samt primater och fåglar separat. Ekvatorialguinea och Gambia avviker från trenden i korrelationen som omfattar alla bedömda arter (sårbara, hotade och akut hotade), vilket gör att de står i fokus för diskussionen. I Ekvatorialguinea är det framför allt primater och växter som relativt sett är mest hotade, medan Gambia främst upplever hot mot fåglar, baserat på måttet “densiteten av hotade arter”. I en undersökning bland 1333 svenskar rankades biståndsalternativ till Afrika. 42% valde demokrati och mänskliga rättigheter som högsta prioritet, 41% humanitärt bistånd, 12% familjeplanering medan endast 5,5 procent valde handel och företagande. Det fanns inga signifikanta skillnader i rangordning av alternativen mellan kön, ålder eller geografisk region, men respondenter med lägre utbildningsnivå var mer benägna att prioritera familjeplanering jämfört med dem med högre utbildning. Trots mycket lite information om familjeplanering i svenska medier och böcker, inser svenskarna dess betydelse för att minska befolkningstillväxten i Afrika. Den mänskliga befolkningstillväxten måste vara en del av den offentliga debatten och policy.The global population crisis remains underrepresented in public discourse, despite its critical impact on biodiversity and sustainable development. Population growth intensifies environmental challenges such as habitat loss, exploitation of resources, and greenhouse gas emissions. This thesis examines 1) the relationship between human population density and the threat to wild species in countries in Sub-Saharan Africa, nearly all of which face high population growth, and 2) public support to family planning in international aid to Africa in a donor country, Sweden. Correlation analyses with data from the IUCN Red List and population metrics from the World Bank show a positive association between human population density and species threats across the following taxonomic groups: all assessed vulnerable, endangered, and critically endangered species, Animalia, Plantae, Primates and birds combined, and primates and birds separately. Equatorial Guinea and the Gambia, deviate from the trend in the graph including all assessed species (vulnerable, endangered, and critically endangered), making them the focal point of discussion. In Equatorial Guinea, primates and plants are particularly threatened, while the Gambia mainly experiences threats to birds, both based on the measure species threat density. In a survey among 1,333 Swedes, they ranked foreign aid alternatives to Africa. 42% chose democracy and human rights as the highest priority, 41% chose humanitarian aid, 12% chose family planning, while only 5.5% chose trade and business. There were no significant differences in rankings across gender, age, or geographic region; however, respondents with lower education levels were more likely to prioritize family planning compared to those with higher education. Despite little information in Swedish media and books about family planning, Swedes recognized its importance in reducing population growth in Africa. Human population dynamics need to be part of public discourse and policies
Reassessing FDI Logic Under Institutional Change. A Qualitative Study of Foreign Firms’ Perceptions of OLI Advantages in a Post-Brexit United Kingdom
Get PDFThis study examines how Brexit has affected companies’ perceptions of the UK as a destination for foreign direct investment (FDI). The qualitative study is based on seven in-depth interviews with representatives of firms operating in the UK, and one pilot interview with a long-term resident with business-related experience in Ireland.
The study adopts an abductive approach and applies the OLI paradigm, the four FDI motives and the Uppsala internationalisation model to assess how Brexit has affected strategic decision-making. The combination of these frameworks provides a dynamic perspective on how institutional change influences internationalisation.
The findings suggest that the increased uncertainty has brought significant challenges, particularly for companies in export- and import-based industries. Furthermore, while the UK remains an important domestic market, companies' investment logic has become more cautious and dependent on firms’ ability to manage institutional uncertainty.
Brexit has weakened several aspects of the UK's location- specific advantages, and the study suggests that while some companies have managed to adapt through operational changes, others have experienced more profound disturbances.
Finally, this study recommends that managers align investment motives with institutional stability and focus on building valuable relationships and internal capabilities to manage uncertainty
ESTIMATING LEAF AREA DENSITY (LAD) ACROSS URBAN TREE GENERA USING LIDAR DATA
Get PDFUrban greenery provides natural processes that benefit human well-being, called ecosystem services,
such as climate change mitigation and is an important factor for establishing sustainable cities. Some
ecosystem services, such as carbon fixation, providing space for Particulate Matter (PM) deposition, and
temperature cooling because of transpiration are partly dependant on the structure of the canopy, which
can be investigated by the estimation of leaf area density (LAD (m2
/m3
)). To facilitate urban planning
and evaluation of possible effectiveness of ecosystem services, allometric relationships are used to
establish correlation between morphological variables such as crown diameter, tree height, diameter at
breast height (DBH) and age. The aim of this study was to estimate LAD from LiDAR (Light Detection
and Ranging) scanned urban trees situated in the City of Malmö and additionally investigate whether
differences between tree genera could be found and if LAD could be correlated to allometric variables
(crown diameter, tree age, height and DBH). Investigation of whether allometric relationships for the
growth of urban trees could be established was also conducted. Around 2 100 urban trees, scanned by a
terrestrial scanner, were analysed. The point clouds for each individual tree were filtered and divided in
halves to account for trees only being scanned from one direction, hence keeping the scanned side. The
side that had been scanned directly was used in the analysis. The four most prominent genera (Tilia spp.,
Quercus spp., Sorbus spp., and Acer spp.) were analysed separately. The estimation of LAD was done
through the Voxel-based Canopy Profiling (VCP) method. Estimated LAD was correlated against
allometric variables, with crown diameter, tree height, DBH, and tree age as the explanatory variables.
The allometric variables were also plotted against each other, with DBH and tree age as the explanatory
variables. The results indicated that LAD was strongly, negatively and non-linearly correlated to crown
diameter (Radj
2
> 0.68) and moderately correlated to tree height (Radj
2
> 0.54). A multiple regression
analysis between crown diameter, tree height and LAD resulted in a statistically significant model with
Radj
2
= 0.70, indicating that an additional 2 percentage points could be added by tree height in addition
to crown diameter to explain LAD variability. No correlation was found between LAD and tree age or
DBH. Comparison of LAD between different tree genera showed a slightly higher LAD for Sorbus spp.
and slightly lower for Acer spp., however, variation of crown size seemed to be much more important
for LAD estimation than the genus of the tree. This might be the result of the pruning of urban trees,
resulting in crown diameter not being dependant on age or DBH for its size. Correlation between tree
height and crown diameter was found (Radj
2
= 0.60), but no correlation between DBH and crown diameter
or tree height could be established. The results indicate that the tree height and crown diameter are more
defining parameters than tree genus when estimating LAD, and for future modelling of LAD,
establishing a function based on crown diameter and tree height might be useful for estimating LAD
without the need for LiDAR scans of the canopy
Mellan craving och kunskap
Get PDFUppsats/Examensarbete: 15 Hp. Kurs: L9HK2G. Nivå: Grundnivå. Ämneslärarprogrammet med inriktning mot årskurs 7–9 i Hem- och konsumentkunskap. Termin/år: VT/2025 Handledare: Hillevi Prell. Examinator: Marianne Pipping EkströmKonsumtionen av ultraprocessade livsmedel har ökat bland unga. Detta väcker oro kring hur det påverkar deras hälsa, välmående och framtida livsvillkor. Denna systematiska forskningsöversikt undersöker sambandet mellan ultraprocessad mat, såsom snabbmat och ungdomars hälsa samt hur socioekonomiska faktorer formar deras matvanor och matval. Studien belyser även hur skolämnet hem- och konsumentkunskap kan bidra till att främja hälsosamma levnadsvanor i unga år.
Genom en strukturerad litteratursökning i flera vetenskapliga databaser valdes tolv peer review-granskade artiklar ut enligt tydliga inklusions- och exklusionskriterier. PICO-modellen användes för att utveckla sökstrategin och säkerställa relevans i urvalet. Resultatet visar att ungdomars matvanor påverkas av faktorer som socioekonomisk status, utbildningsnivå, tillgång till näringsrik mat och kulturella normer. En hög konsumtion av ultraprocessad mat som är energität och näringsfattig kopplas till övervikt, psykisk ohälsa och sämre skolprestationer. Samtidigt framstår socioekonomisk status som en central påverkansfaktor, där ekonomiska resurser ofta avgör möjligheten till hälsosamma val. I vissa fall kan dock hög konsumtion även förekomma i grupper med hög socioekonomisk status. Studien understryker vikten av fortsatt forskning inom området samt behovet av stärkt kompetens bland hem- och konsumentkunskapslärare, i syfte att möta folkhälsoutmaningar och minska ojämlikhet i levnadsvillkor för unga
NÄR T:ET I HBTQI HAMNAR I CENTRUM. En studie av de parlamentariska initiativen om transpersoner i Sveriges riksdag 1998–2024
Get PDFSyftet med denna uppsats är att beskriva och förklara de svenska politiska partiernas
parlamentariska arbete i riksdagen rörande frågor om transpersoner. Tidigare forskning från
framför allt USA visar att frågor om transpersoner har kommit att få ett allt större utrymme i
det parlamentariska arbetet, inte minst genom att antal lagförslag som kan bedömas ha negativa
konsekvenser för transpersoner har ökat det senaste decenniet. Motsvarande forskning saknas i
Sverige och vi har idag begränsad kunskap om de svenska partiernas strategier rörande frågor
om transpersoner. Genom en kvantitativ studie har jag sammanställt de 348 parlamentariska
initiativ som gjorts rörande frågor om transpersoner i Sveriges riksdag mellan 1998 och 2024.
Jag analyserar resultatet av min undersökning i en teorikonsumerande studie där primärt
medianväljarteorin och saliency-teorin används för att försöka förklara de svenska partiernas
parlamentariska strategier kopplat till frågor om transpersoner. Resultaten av studien visar att
det skett en ökad polarisering i riksdagen det senaste decenniet och att det finns stora likheter
med utvecklingen på federal- och delstatsnivå i USA. Resultaten visar vidare på tydliga
skillnader i partiernas strategier, både när det kommer till i vilken utsträckning partierna
prioriterar frågor om transpersoner och hur man driver frågorna, och att dessa strategier i
begränsad utsträckning kan förklaras med etablerade partiteorier
The importance of membrane order in T cell signalling and viral infection
Get PDFThe plasma membrane is a dynamic and heterogeneous structure, whose lateral organization into lipid nanodomains critically regulates cellular processes such as signaling, adhesion, and pathogen entry. In T cells, membrane order, which reflects the degree of lipid packing, plays a pivotal role in organizing signaling platforms and modulating immune responses. In this thesis, membrane order was investigated using the environment-sensitive fluorescence probes Laurdan and C-laurdan, with generalized polarization (GP) used to quantify lipid packing.
Paper I presents an optimized GP imaging approach for C-laurdan-labeled T cells by introducing a systematic deconvolution protocol. Deconvolution improved the spatial resolution of fluorescence images, enabling more accurate delineation of plasma membrane regions of interest (ROIs) and enhancing the sensitivity for detecting differences in membrane order between plasma and intracellular membranes. A detailed protocol for optimizing deconvolution parameters was established, allowing for reproducible and higher-precision GP measurements.
Paper II investigates how different substrate types and environmental conditions influence T cell plasma membrane order at the equatorial plane and examines how these factors relate to early activation events. Laurdan-based imaging revealed that membrane order at the equatorial plane did not differ significantly across conditions, including CD3- and CD45-functionalized supported lipid bilayers, PLL-coated surfaces, hydrogels, and microfluidic suspension. Although CD3-functionalized SLBs showed a non-significant trend toward increased membrane order, changes were subtle overall. Cells in suspension exhibited a wider range of GP values, while those in hydrogels showed no significant increase in order compared to TESPA. Calcium imaging demonstrated that CD3-functionalized SLBs triggered significantly faster responses than CD45-functionalized SLBs, despite both supporting similar activation levels. Additionally, PLL-coated surfaces induced a higher fraction of activated cells compared to TESPA, though with similar timing. These findings indicate that while substrate composition and receptor engagement strongly influence early signalling dynamics, they do not induce major changes in global membrane order at the equator.
Paper III examines the effects of simvastatin on plasma membrane organization and SARS-CoV-2 infection. Treatment with simvastatin reduced plasma membrane order, as assessed by C-laurdan GP imaging, and led to a significant decrease in both intracellular viral load and extracellular virus release in lung epithelial cells. These effects were not solely explained by alterations in ACE2 expression, suggesting that modulation of membrane order contributed directly to limiting viral infection and propagation.
Overall, this thesis demonstrates that plasma membrane order is a key determinant in T cell signaling and viral infection. By advancing imaging methodologies and elucidating the interplay between membrane organization and cellular function, this work provides new insights into the biophysical regulation of immune responses and identifies membrane order as a potential target for therapeutic intervention
Sanning med modifikation? Förekomsten av och förklaringar till resultatjusteringar i kommuner
Get PDFSyfte: Studien syftar att undersöka huruvida resultatjustering förekommer bland svenska kommuner samt hur finansiell hållbarhet inom kommuner påverkar graden av resultatjustering. Med hjälp av offentliga data testas ett antal hypoteser relaterade till finansiell hållbarhet och deras påverkan på onormala periodiseringar som proxy för graden av resultatjustering. Teori: Studien använder sig av public choice teorin som referensram och kompletteras av tidigare forskning. Public choice teorin bygger på klassiska
ekonomiska teorier och är anpassad för den offentliga sektorn. Grundantaganden är bland annat att människan är en rationell individ där nyttomaximering och självintresse är centrala teman. Metod: Studien antar en kvantitativ ansats och bygger på data från 289 av Sveriges kommuner för perioden 2000–2023. Statistikprogrammet Stata har använts för både bearbetning av data samt olika statistiska tester. För att undersöka de samband hypoteserna antar föreligga, genomförs ett antal tester. Test utav
frekvensfördelningen av kommuners resultat, test av skillnader i medelvärden mellan grupper samt multivariata regressionsanalyser har genomförts. Resultat: Studien finner att flera av de samband som upptäckts i andra länder inom tidigare forskning överensstämmer med den kommunala sektorn i Sverige. Kommuner tycks ägna sig åt resultatjustering för att redovisa små positiva
resultat. En betydande skillnad gentemot tidigare forskning är att desto bättre rustad kommuners kortsiktiga betalningsförmåga är, desto högre grad av resultatjustering förekommer. Studien finner därutöver att de studerade sambanden delvis håller även på lång sikt