| 1. |
- Abdeljaber, Osama, et al.
(författare)
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Analysis of the Trajectories of Left-turning Vehicles at Signalized Intersections
- 2020
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Ingår i: Transportation Research Procedia. - : Elsevier BV. ; , s. 1288-1295, s. 1288-1295
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Konferensbidrag (refereegranskat)abstract
- Internationally, an annual number of more than a million fatalities are caused by road traffic crashes, with particularly signalized intersections being crash prone locations within the highway system. An accumulation of conflicts between drivers is caused by the different movements (through and turning) from different directions at the intersection; hence, studying the trajectories of turning vehicles is an important step towards improving traffic safety performance of these facilities. In view of that, the current paper aims at providing further insight into the behaviour of left-turning vehicles (right-hand traffic rule) at signalized intersections in the State of Qatar. At first, a total of 44 trajectories of free-flowing vehicles were manually extracted from a recorded video for a single approach of Lekhwair signalized intersection in Doha City, State of Qatar. After that, the extracted trajectories were statistically analysed in an attempt to explore the factors affecting the path of left-turning vehicles at signalized intersections. The results suggest that the characteristics of the extracted paths are significantly related to the vehicle’s entry speed, minimum speed throughout its turning manoeuvre, and the lateral distance between the exit point and the curb (i.e., targeted exit lane). Provided that the speed parameters can be fairly an indication to the driving behaviour, it can be concluded that the driver’s attitude plays an important role in drawing the manoeuvre of a turning vehicle as does the pre-selection of the exit lane. Finally, the effort presented in this paper can be regarded as a way forward towards understanding the behaviour of turning vehicles at signalised intersection in the State of Qatar.
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| 2. |
- Abdeljaber, Osama, et al.
(författare)
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Extraction of Vehicle Turning Trajectories at Signalized Intersections Using Convolutional Neural Networks
- 2020
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Ingår i: Arabian Journal for Science and Engineering. - Heidelberg : Springer. - 2193-567X .- 2191-4281 .- 1319-8025. ; 45, s. 8011-8025
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims at developing a convolutional neural network (CNN)-based tool that can automatically detect the left-turning vehicles (right-hand traffic rule) at signalized intersections and extract their trajectories from a recorded video. The proposed tool uses a region-based CNN trained over a limited number of video frames to detect moving vehicles. Kalman filters are then used to track the detected vehicles and extract their trajectories. The proposed tool achieved an acceptable accuracy level when verified against the manually extracted trajectories, with an average error of 16.5 cm. Furthermore, the trajectories extracted using the proposed vehicle tracking method were used to demonstrate the applicability of the minimum-jerk principle to reproduce variations in the vehicles’ paths. The effort presented in this paper can be regarded as a way forward toward maximizing the potential use of deep learning in traffic safety applications.
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| 3. |
- Aguilera, Anabella, et al.
(författare)
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Ecophysiological analysis reveals distinct environmental preferences in closely related Baltic Sea picocyanobacteria
- 2023
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Ingår i: Environmental Microbiology. - Chichester : John Wiley & Sons. - 1462-2912 .- 1462-2920. ; 25:9, s. 1674-1695
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Tidskriftsartikel (refereegranskat)abstract
- Cluster 5 picocyanobacteria significantly contribute to primary productivity in aquatic ecosystems. Estuarine populations are highly diverse and consist of many co-occurring strains, but their physiology remains largely understudied. In this study, we characterized 17 novel estuarine picocyanobacterial strains. Phylogenetic analysis of the 16S rRNA and pigment genes (cpcBandcpeBA) uncovered multiple estuarine and freshwater-related clusters and pigment types. Assays with five representative strains (three phycocyanin rich and two phycoerythrin rich) under temperature (10–30°C), light(10–190 μmol photons m-2s-1), and salinity (2–14 PSU) gradients revealed distinct growth optima and tolerance, indicating that genetic variability was accompanied by physiological diversity. Adaptability to environmental conditions was associated with differential pigment content and photosynthetic performance. Amplicon sequence variants at a coastal and an offshore station linked population dynamics with phylogenetic clusters, supporting that strains isolated in this study represent key ecotypes within the Baltic Sea picocyanobacterial community. The functional diversity found within strains with the same pigment type suggests that understanding estuarine picocyanobacterial ecology requires analysis beyond the phycocyanin and phycoerythrin divide. This new knowledge of the environmental preferences in estuarine picocyanobacteria is important for understanding and evaluating productivity in current and future ecosystems.
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| 4. |
- Alegria Zufia, Javier, Ph.D. 1992-, et al.
(författare)
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Growth and mortality rates of picophytoplankton in the Baltic Sea Proper
- 2024
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Ingår i: Marine Ecology Progress Series. - Oldendorf : Inter-Research. - 0171-8630 .- 1616-1599. ; 735, s. 63-76
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Tidskriftsartikel (refereegranskat)abstract
- Picophytoplankton (<2 µm diameter), a diverse group of picocyanobacteria and photosynthetic picoeukaryotes, are significant contributors to primary production. Predatory mortality controls picophytoplankton biomass and thereby energy transfer in the marine food web. The 2 major pathways of picophytoplankton mortality are grazing and viral lysis. Grazing passes carbon directly to higher trophic levels, while lysis products are passed into the viral loop. Picophytoplankton are abundant in the Baltic Sea but little is known about their predatory mortality. Using a modification of the dilution approach, we calculated growth and mortality rates of picophytoplankton and studied the effect of predation on community structure during late August and September. The experiments were conducted coinciding with the peak in picophytoplankton abundance (similar to 10(5) cells ml(-1)) at the Linnaeus Microbial Observatory in the Baltic Sea Proper. The results showed that grazing is an important controller of picocyanobacteria and photosynthetic picoeukaryote populations, while no significant viral lysis effect was detected. Grazing on picocyanobacteria was proportional to growth rates, while grazing on photosynthetic picoeukaryotes exceeded growth. Selective grazing of phylogenetically distinct picocyanobacterial clades had a significant effect on community structure, suggesting that grazing has an impact on the seasonal dynamics of co-occurring clades. Picocyanobacteria had a higher carbon transfer contribution to higher trophic levels than photosynthetic picoeukaryotes at the time of the experiments. The study shows that picophytoplankton are important contributors to carbon cycling in the Baltic Sea microbial food web and should be considered for future ecological models.
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| 5. |
- Alegria Zufia, Javier, Ph.D. 1992-, et al.
(författare)
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Seasonal dynamics in picocyanobacterial abundance and clade composition at coastal and offshore stations in the Baltic Sea
- 2022
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Ingår i: Scientific Reports. - London : Nature Publishing Group. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Picocyanobacteria (< 2 um in diameter) are significant contributors to total phytoplankton biomass. Due to the high diversity within this group, their seasonal dynamics and relationship with environmental parameters, especially in brackish waters, are largely unknown. In this study, the abundance and community composition of phycoerythrin rich picocyanobacteria (PE-SYN) and phycocyanin rich picocyanobacteria (PC-SYN) were monitored at a coastal (K-station) and at an offshore station (LMO; similar to 10 km from land) in the Baltic Sea over three years (2018-2020). Cell abundances of picocyanobacteria correlated positively to temperature and negatively to nitrate (NO3) concentration. While PE-SYN abundance correlated to the presence of nitrogen fixers, PC-SYN abundance was linked to stratification/shallow waters. The picocyanobacterial targeted amplicon sequencing revealed an unprecedented diversity of 2169 picocyanobacterial amplicons sequence variants (ASVs). A unique assemblage of distinct picocyanobacterial clades across seasons was identified. Clade A/B dominated the picocyanobacterial community, except during summer when low NO3, high phosphate (PO4) concentrations and warm temperatures promoted S5.2 dominance. This study, providing multiyear data, links picocyanobacterial populations to environmental parameters. The difference in the response of the two functional groups and clades underscore the need for further high-resolution studies to understand their role in the ecosystem.
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| 6. |
- Alegria Zufia, Javier, et al.
(författare)
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Seasonality of Coastal Picophytoplankton Growth, Nutrient Limitation, and Biomass Contribution
- 2021
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Ingår i: Frontiers in Microbiology. - Lausanne : Frontiers Media S.A.. - 1664-302X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Picophytoplankton in the Baltic Sea includes the simplest unicellular cyanoprokaryotes (Synechococcus/Cyanobium) and photosynthetic picoeukaryotes (PPE). Picophytoplankton are thought to be a key component of the phytoplankton community, but their seasonal dynamics and relationships with nutrients and temperature are largely unknown. We monitored pico- and larger phytoplankton at a coastal site in Kalmar Sound (K-Station) weekly during 2018. Among the cyanoprokaryotes, phycoerythrin-rich picocyanobacteria (PE-rich) dominated in spring and summer while phycocyanin-rich picocyanobacteria (PC-rich) dominated during autumn. PE-rich and PC-rich abundances peaked during summer (1.1 x 10(5) and 2.0 x 10(5) cells mL(-1)) while PPE reached highest abundances in spring (1.1 x 10(5) cells mL(-1)). PPE was the main contributor to the total phytoplankton biomass (up to 73%). To assess nutrient limitation, bioassays with combinations of nitrogen (NO3 or NH4) and phosphorus additions were performed. PE-rich and PC-rich growth was mainly limited by nitrogen, with a preference for NH4 at >15 degrees C. The three groups had distinct seasonal dynamics and different temperature ranges: 10 degrees C and 17-19 degrees C for PE-rich, 13-16 degrees C for PC-rich and 11-15 degrees C for PPE. We conclude that picophytoplankton contribute significantly to the carbon cycle in the coastal Baltic Sea and underscore the importance of investigating populations to assess the consequences of the combination of high temperature and NH4 in a future climate.
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| 7. |
- Andersson, Svante, 1962-, et al.
(författare)
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Combining industrial buyer and seller strategies for international supply and marketing management
- 2010
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Ingår i: European Business Review. - London : Emerald Group Publishing Limited. - 0955-534X .- 1758-7107. ; 22:1, s. 64-81
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this paper is to review international industrial purchasing and marketing literature with a focus on portfolio models, to develop portfolio models for buyers' and sellers' international strategies, and to combine the models so that both the buyer and seller perspectives are dealt with simultaneously. Design/methodology/approach: Literature on international industrial purchasing and marketing is discussed. Dimensions that are important for the buyers' and sellers' strategies are identified. Portfolio models for buyers and sellers are developed and the two perspectives are matched together. Findings: The paper contributes a specification of features that are important for industrial buyers' and sellers' international purchasing and marketing strategies. These dimensions are used to develop a model of supplier relationship management and a marketing management model for supplier strategies. The consequences for the firm's international activities are discussed. A model combining industrial buyers' and sellers' international supply and marketing management strategies is developed. Research limitations/implications: This paper provides a deeper understanding of international exchange processes by combining literature on international industrial purchasing and international marketing. Situations are identified where different areas of theory are applicable. The paper also contributes to the discussion on what should be the conceptual domain of international business. Here, it is argued that international exchange is the product of joint decisions made by two or more actors based in different countries. Earlier academic literature reveals a striking imbalance: while one side of the coin - the exporter side - has been extensively studied, the importer side has largely been neglected. In this paper, it is tried to present a balanced view of both sides. Practical implications: This paper introduces portfolio management models that can be used for both industrial purchasing and marketing management. The paper stresses the importance of finding a fit between the marketing and purchasing strategies within a relationship. If both parties have positioned the relationship in a similar way, there are much greater possibilities for the relationship to create value for both parties. Originality/value: The paper combines international industrial purchasing and international marketing perspectives as few studies have done before. © Emerald Group Publishing Limited.
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| 8. |
- Argento, Daniela, et al.
(författare)
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The ‘externalisation’ of local public service delivery : experience in Italy and Sweden
- 2010
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Ingår i: International Journal of Public Policy. - Olney : InderScience Publishers. - 1740-0600 .- 1740-0619. ; 5:1, s. 41-56
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the local government sector in European countries has undergone important changes involving, among other things, the externalisation of local public service provision through various forms of corporatisation, public-public collaboration, public-private partnerships and contracting out. An important consequence of these institutional changes has been the recasting of local governance systems through the need for increased cooperation between public and private actors. This article addresses these matters with comparative reference to the experience in Italy and Sweden. In doing so, it considers local governments in their constitutional and legal contexts, leading to more detailed discussions of their externalisation initiatives and resultant organisational forms and governance arrangements. Issues of ownership have been important concerning the significance of 'community' and 'place' in the management of public affairs. © 2010 Inderscience Enterprises Ltd.
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| 9. |
- Arvidsson, Barbro, 1945-, et al.
(författare)
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A nurse-led rheumatology clinic’s impact on empowering patients with rheumatoid arthritis : A qualitative study
- 2006
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Ingår i: Nursing and Health Sciences. - Richmond, Australia : Wiley-Blackwell. - 1441-0745 .- 1442-2018. ; 8:133-9
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to describe a nurse-led rheumatology clinic’s impact on empowering patients with rheumatoid arthritis (RA). Rheumatoid arthritis is a chronic, inflammatory disease that attacks many joints, causing considerable functional restrictions for patients. Consequently, these patients are dependent on a wide variety of health-care services. A descriptive, qualitative design inspired by phenomenography was chosen. The conceptions were collected through interviews with 16 strategically selected patients with RA. Three descriptive categories comprising eight conceptions emerged: teaching (gaining insight and receiving information), regular review (receiving security, realizing regularity, and achieving accessibility), and attention (getting a holistic assessment, receiving coordinated care, and getting sufficient time). A nurse-led rheumatology clinic can be a source for empowering patients with RA to adopt new stances to alternative actions and achieve a higher level of faith in their own abilities.
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| 10. |
- Arvidsson, Barbro, et al.
(författare)
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Factors influencing nurse supervisor competence : a critical incident analysis study
- 2005
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Ingår i: Journal of Nursing Management. - Oxford : Blackwell Publishing. - 0966-0429 .- 1365-2834. ; 13:3, s. 231-7
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to identify factors related to critical incidents that influence the competence of nurse supervisors. Nurse supervisors require considerable competence in order to help supervisees to reflect on their clinical work and to interpret the needs of the patient. A qualitative approach involving the critical incident technique was used. Critical incidents were collected by means of self-reports from 25 nurse supervisors. Two main areas emerged: a professional and a personal stance. The professional stance described the nurse supervisors’ awareness of the importance of creating a secure learning environment and facilitating reflection. The supervisors structured the material and created awareness of fundamental nursing values. The second main area, personal stance, described the nurse supervisors’ behaviour when they gave the participating nurses the opportunity to work through the experiences gained in the daily provision of nursing care. Although they experienced lack of self-assurance during the supervision session, they also expressed security regarding their own performance as nurse supervisors. Nurse supervisors need to include more nursing theory and focus on the nursing process as well as being aware of their own shortcomings and resources. One way for the supervisior to scrutinize his/her actions is to discuss and examine them with a more experienced nurse supervisor colleague.
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