| 1. |
- Bruett, Anna Levke, et al.
(författare)
-
Assessment of Health-Related Quality of Life and Patient Satisfaction in Children and Adolescents with Growth Hormone Deficiency or Idiopathic Short Stature - Part 1 : A Critical Evaluation of Available Tools
- 2009
-
Ingår i: Hormone Research. - : S. Karger AG. - 0301-0163 .- 1423-0046. ; 72:2, s. 65-73
-
Forskningsöversikt (refereegranskat)abstract
- The concept of health-related quality of life (HrQoL) reflects the subjective perception of health and includes aspects of well-being and functioning in physical, emotional, mental and social life domains. Nowadays, HrQoL has become a relevant treatment outcome from epidemiological and clinical perspectives and is also broadly employed in health economic analyses. To assess HrQoL generic as well as condition-specific instruments are used. The former are applicable to a wide range of health conditions and aim at measuring HrQoL across different conditions. The latter focus on capturing the impact of a specific disease. Although HrQoL research in adults is now well-advanced, there are still open questions regarding how to assess HrQoL in pediatric conditions, such as short stature. Eight generic (one chronic-generic) and seven condition-specific (one treatment-specific) instruments used in HrQoL research in short stature of youth are described. Additionally, this mini review identifies a need for further research and indicates potential directions.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Sandberg, Jakob, et al.
(författare)
-
Despite high uptake efficiency, non-mycorrhizal Rumex acetosella increases available phosphorous in the rhizosphere soil, whereas Viscaria vulgaris, Plantago lanceolata and Achillea millefolium does not
- 2009
-
Ingår i: Nordic Journal of Botany. - : John Wiley & Sons. - 0107-055X .- 1756-1051. ; 27:5, s. 444-448
-
Tidskriftsartikel (refereegranskat)abstract
- The phosphorous (P) uptake efficiency, reduction of the soil extractable P, and the root morphology was determined for the four common grassland species Rumex acetosella, Viscaria vulgaris, Plantago lanceolata and Achillea millefolium in one pot cultivation and one microcosm experiment. Rumex acetosella produced more than tree times as much biomass as each of V. vulgaris, P. lanceolata and A. millefolium, and could maintain a P concentration in the tissue that was twice as high as in the other species. R. acetosella was able to take up 10 times more phosphorous than the other species but the high uptake was not reflected in reduced Olsen P levels in the root affected soil. Calculating the uptake efficiency of the roots with a diameter less than 0.5 mm showed that the P uptake, calculated per root area, had been more efficient in R. acetosella than in the other species. The calculated rhizosphere volume (explored by the plant) seemed to correlate with the higher uptake efficiency of R. acetosella. We can conclude that R. acetosella have mechanisms to maintain a high P availability in the soil and may sustain a high uptake without any mycorrhizal interactions.
|
|
| 10. |
- Sandberg, Sara
(författare)
-
Low-density parity-check codes : unequal error protection and reduction of clipping effects
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The invention of low-density parity-check (LDPC) codes made reliable communication possible at transmission rates very close to the theoretical limit predicted by Shannon. However, communication close to the Shannon limit requires very long codes and results in long delay and high encoder and decoder complexity. In many communication scenarios, constraints on delay, complexity and power prohibit communication with arbitrarily low error probability. To achieve good performance it is then important that the code is appropriately matched to the other parts of the communication system. In this thesis, LDPC codes for two different communication scenarios are studied. A common scenario is communication of information bits with unequal importance for the perceptual quality after source decoding. This is the case for example in many networks and for transport of multimedia data, where one frame may consist of a header, some payload and additional payload for increased quality. Errors in the header data may cause the whole frame to be useless, while errors in the additional payload generally cause only a small quality reduction. A code with unequal error protection (UEP) is designed to protect some bits more than others, thus providing a reduced bit-error rate (BER) for the important bits. This work studies design of LDPC codes with UEP capability for bandwidth-efficient higher order constellations. A flexible design algorithm for irregular UEP-LDPC codes is proposed, which is applicable to arbitrary signal constellations, an arbitrary number of classes of bits with different importance and arbitrary sizes of the classes. Simulations using 8-PSK modulation show that the overall BER is reduced if codes are properly designed for the modulation scheme, compared to the BER achieved by standard UEP codes designed for BPSK modulation. Codes designed by the proposed algorithm also provide more UEP capability, especially at high SNR. Moreover, further work shows that the UEP capability of an irregular LDPC code is not only dependent on the variable node degrees as is widely believed. The LDPC construction algorithms, that place the edges in the graph according to the degree distributions, also play a critical role for the UEP behavior of an LDPC code. The differences in UEP capability are explained by introduction of detailed check node degree distributions that describe differences in the code structure.LDPC codes for the orthogonal frequency division multiplexing (OFDM) system are also studied. OFDM enables simple equalization and has been adopted in several standards. However, OFDM is sensitive to frequency-selective fading and introduces a large peak-to-average power ratio (PAPR) of the transmitted signal. These problems can be alleviated by pre-multiplying the OFDM block with a spreading matrix that both reduces the PAPR of the transmitted signal and increases the frequency diversity. Simulation of an OFDM system with clipping shows that the performance gain by spreading is substantial also when an LDPC code, which on its own improves the performance significantly, is applied to the OFDM system. PAPR reduction may also be achieved by deliberate clipping of the signal, prior to the transmitter high-power amplifier. Clipping will however introduce losses and receiver methods to mitigate such clipping losses are investigated. We consider Bayesian estimation of the unclipped signal as well as statistical characterization of the clipping distortion, that is fed to the LDPC decoder. The results show that for an LDPC coded OFDM system, the improvement by these clipping mitigation methods is minimal.
|
|
