| 811. |
- Persson, Anders
(author)
-
Consumption patterns and excretion in aquatic food websenrichment
- 1997
-
Doctoral thesis (other academic/artistic)abstract
- This thesis links biogeochemical cycling to classical ecology. Predictions derived from food chain theory, based on Lotka-Volterra type of interactions, were tested in aquatic environments with the main hypothesis that consumers affect lower levels of organization by both predation and excretion of limiting nutrients. From tank experiments it was concluded that predation may affect prey populations in agreement with food chain theory, but that species replacement within the prey community confounds predictions based on trophic level dynamics. By describing ecosystems as a matrix of food web interactions, and by recognizing the interplay between competition and predation, a more complete description of the ecosystem function was obtained compared to when species were placed into distinct trophic levels. Results from experimental studies showed that the effects of fish on nutrient cycling could provide a complement to zooplanktivory in explaining algae dynamics. It was argued that the concept of carrying capacity, as used in food chain theory, prevents an adequate understanding of cascading trophic interactions. Hence, producer growth rate is determined by the availability of nutrients, which is partly set by the recycling by consumers, rather than the total amount of nutrients present in a system. Determination of the relative importance of phosphorus (P) excretion by fish in comparison to other P sources was performed for a hypertrophic lake. The results showed that excretion by fish may be of the same magnitude as the external load, but it did only explain a minor part of the internal load. In contrast, model simulations of the P dynamics of a hypertrophic lake showed that excretion of P by fish could be a significant part of the total P supply to phytoplankton growth, mostly due to translocation of P from the sediment to the water by benthic feeding fish. The simulations suggested that P was routed along the pelagic food chain to a larger extent if omnivorous fish biomass was reduced (biomanipulation), whereas the amount of phosphorus routed via the sediment and benthivorous fish decreased after biomanipulation. However, field studies in a hypertrophic lake showed that the overlap in resource utilization within the fish community was considerable, resulting in compensatory responses when the fish community was manipulated. Such responses may offset the anticipated effects of biomanipulation, a method proposed for the restoration of eutrophicated lakes.
|
|
| 812. |
- Persson, Anders, et al.
(author)
-
Contested technologies
- 2008. - 1
-
Book (other academic/artistic)abstract
- Addressing the important perspectives on xenotransplantation and human embryonic stem cell research, this book explores both the enthusiastic proponents and vehement resistance to these new biomedical technologies. Investigating the political, social, and ethical forces behind this kind of research and development, as well as the commercial actors and strong financial incentives that are necessary, these stories of hope, fear, and hype are matched by stories of success, failure, and fraud, showing how these technologies have become truly polarizing.
|
|
| 813. |
- Persson, Anders, 1953-
(author)
-
CT colonography
- 2005
-
In: Nordisk kongress i multidetektor CT,2005.
-
Conference paper (other academic/artistic)
|
|
| 814. |
- Persson, Anders, 1953-
(author)
-
CT Colonography
- 2002
-
In: Regionmöte i Radiologi, Västervik, maj 2002,2002.
-
Conference paper (peer-reviewed)
|
|
| 815. |
- Persson, Anders
(author)
-
Defining, Securing and Building a Just Peace : The EU and the Israeli-Palestinian conflict
- 2013
-
Doctoral thesis (other academic/artistic)abstract
- Just peace has been much talked about in everyday life, but it is less well researched by academics. The puzzle underlying this dissertation is therefore to probe what constitutes a just peace, both conceptually within the field of peacebuilding and empirically in the context of the EU as a peacebuilder in the Israeli-Palestinian conflict. The EU has used the term just peace in many of its most important declarations on the Israeli-Palestinian conflict throughout the years. Defining a just peace is about these declaratory efforts by the EU to articulate a common formula of a just peace in the conflict. Securing and building a just peace are about the EU’s role in implementing this formula for a just peace in the conflict through the creation of a Palestinian state. As the EU enters its fifth decade of involvement in the conflict, there can be little doubt that in common with the rest of the international community it has failed in its efforts to establish a just peace between Israelis and Palestinians. While this is an inescapable overall conclusion from four decades of EC/EU peacebuilding in the conflict, it is, at the same time, possible to draw a number of other conclusions from this study. Most importantly, it will be argued that the EU is a major legitimizing power in the conflict and that it has kept the prospects of a two-state solution alive through its support for the Palestinian statebuilding process.
|
|
| 816. |
|
|
| 817. |
|
|
| 818. |
|
|
| 819. |
- Persson, Anders, 1982-, et al.
(author)
-
Disrupting Blood Gas Analysis, Path to Rapid, Gentle and Continuous Monitoring : DBGA
- 2020
-
Conference paper (other academic/artistic)abstract
- For prematurely born children, yearly amounting to 15 million, monitoring of CO2 content in the blood is vital. Clinically, either ablood sample is taken, limiting the number of measurements and delaying the information, or a method detecting the gas escapingthrough the skin on heating it, is used. The latter poses severe risks of injury either by the heat itself or from skin rupturing onremoving the sensor. Here, a truly non-invasive concept has been fully prototyped and benchmarked. It allows for continuous, nonlagging,measurements of a quality seemingly outperforming state-of-the-art equipment, also on body parts previously considereddisqualified.
|
|
| 820. |
- Persson, Anders, 1975
(author)
-
Diversity and Interference Aspects in the Downlink of Code Division Multiple Access Systems
- 2004
-
Doctoral thesis (other academic/artistic)abstract
- This thesis consists of six included papers and technical reports, plus an introduction. The topic studied is interference and diversity aspects in code division multiple access (CDMA) systems for mobile cellular communications. The focus in the papers is on the downlink - the communication link from the base station to the mobile terminal. A performance limiting factor in the downlink of single-carrier CDMA systems is multiple access interference due to lost orthogonality on the time-dispersive radio channel. On such channels, orthogonal frequency division multiplexing (OFDM) is a very powerful technique and, recently, several proposals of CDMA for OFDM systems have been made. Although some results for single-carrier systems are provided (paper A), it is to the area of OFDM-CDMA that the main contributions of this thesis are made (papers B-F). In the included papers, low-complexity single-user detectors are assumed. In agreement with existing results, it is concluded that direct-sequence spreading in OFDM systems is beneficial when the number of active users is low compared to the length of the spreading codes used, i.e., for low system loads. However, assuming a single-cell scenario and a channel code of a sufficiently large free distance, it is at high system loads concluded that coded orthogonal frequency division multiplexing access (OFDMA) outperforms all the considered direct-sequence schemes. This is most clearly the case in a near-far scenario - a situation that naturally will occur in the downlink due to the requirement for different transmit powers for different users. It is also concluded that coded OFDMA achieves essentially the same robustness against inter-cell interference as schemes that use direct-sequence spreading. If a low complexity detector is required, the results presented in this thesis indicate that coded OFDMA is a competitive candidate for the downlink of mobile cellular systems.
|
|
