97 research outputs found
Lung Imaging and Function Assessment using Non-Contrast-Enhanced Magnetic Resonance Imaging
Measurement of pulmonary ventilation and perfusion has significant clinical value for the diagnosis and monitoring of prevalent lung diseases. To this end, non-contrast-enhanced MRI techniques have emerged as a promising alternative to scintigraphical measurements, computed tomography, and contrast-enhanced MRI. Although these techniques allow the acquisition of both structural and functional information in the same scan session, they are prone to robustness issues related to imaging artifacts and post-processing techniques, limiting their clinical utilization. In this work, new acquisition and post-processing techniques were introduced for improving the robustness of non-contrast-enhanced MRI based functional lung imaging. Furthermore, pulmonary functional maps were acquired in 2-year-old congenital diaphragmatic hernia (CDH) patients to demonstrate the feasibility of non-contrast-enhanced MRI methods for functional lung imaging.
In the first study, a multi-acquisition framework was developed to improve robustness against field inhomogeneity artifacts. This method was evaluated at 1.5T and 3T field strengths via acquisitions obtained from healthy volunteers. The results demonstrate that the proposed acquisition framework significantly improved ventilation map homogeneity p<0.05.
In the second study, a post-processing method based on dynamic mode decomposition (DMD) was developed to accurately identify dominant spatiotemporal patterns in the acquisitions. This method was demonstrated on digital lung phantoms and in vivo acquisitions. The findings indicate that the proposed method led to a significant reduction in dispersion of estimated ventilation and perfusion map amplitudes across different number of measurements when compared with competing methods p<0.05.
In the third study, the free-breathing non-contrast-enhanced dynamic acquisitions were obtained from 2-year-old patients after CDH repair, and then processed using the DMD to obtain pulmonary functional maps. Afterwards, functional differences between ipsilateral and contralateral lungs were assessed and compared with results obtained using contrast-enhanced MRI measurements. The results demonstrate that pulmonary ventilation and perfusion maps can be generated from dynamic acquisitions successfully without the need for ionizing radiation or contrast agents. Furthermore, lung perfusion parameters obtained with DMD MRI correlate very strongly with parameters obtained using dynamic contrast-enhanced MRI.
In conclusion, the presented work improves the robustness and accuracy of non-contrast-enhanced functional lung imaging using MRI. Overall, the methods introduced in this work may serve as a valuable tool in the clinical adaptation of non-contrast-enhanced imaging methods and may be used for longitudinal assessments of pulmonary functional changes
Children's adjustment to asthma or diabetes and treatment adherence
This thesis had two main aims. Firstly, to develop separate questionnaires for
children with asthma and children with diabetes and their parents, which assess
children's adjustment to the illness and treatment adherence. Secondly, to test
the hypothesis of an association between children's adjustment and treatment
adherence.
The essence of asthma and diabetes treatment is self-care and consequently
children with asthma or diabetes have to learn to cope with the long-term
demands and responsibilities of complying with a strict and complex treatment
regimen. It is currently recognized that a major problem in paediatrics is poor
treatment adherence, which can result in serious health consequences. This led
to a shift in paediatric medicine, from focusing only on the physical treatment of
the illness to exploring the psychological impact of the illness and how it affects
children's socio-emotional adjustment. However, there is a shortage of
adjustment and treatment adherence measures; existing ones have major
limitations. Thus, the new questionnaires aimed at assessing both children's
adjustment and treatment adherence.
Four interlinked studies utilising qualitative and quantitative methods were
carried out. Study 1 and study 3 were parallel but separate studies and involved
interviewing a group of 15 children with asthma and 15 children with diabetes,
their parents and paediatric nurses about the children's experiences and
feelings in a range of contexts.
The interviews showed that there were commonalities in stressors across
children but differences in adjustment and treatment adherence levels.
On the basis of these interviews separate questionnaires for children with
asthma (study 2) and children with diabetes (study 4) and their parents were
developed and administered to a sample of 60 children and their parents. The
new questionnaires proved to be reliable and valid and confirmed the
hypothesis of a significant relation between children's adjustment and treatment
adherence.
The development of a new assessment tool involves several steps: This work
represents the first steps in developing a new assessment tool. As with any new
assessment instrument, further development will be required to examine its
validity and reliability
SOSYAL MEDYAYA HALKLA İLİŞKİLER PERSPEKTİFİNDEN ELEŞTİREL BİR BAKIŞ
In a digital world where concepts have lost what they denote step by step and where bodies are expropriated, souls connected to the computer screen with one touch display their lives in an unveiled manner to everybody. Despite this remonstrance, we voluntarily share our loved ones, our lives, our ideologies, our fears and our obsessions and peep each other. Even people, who were otherized and isolated in the real world, have found a place for themselves in society thanks to the Internet. Multiple selves connected to each other through fiber optic cables are trying to adapt to this new media order brought by these new technologies. Job descriptions of public relations specialists are constantly changing in this cyber age when institutions also have gained identity just like individuals. This study has significance in terms of redefining the roles undertaken through the public relations experts, with an eye to comply with the system who strive to be within the in social media and interpret same with a critical approach
Variability along the Atlantic water pathway in the forced Norwegian Earth System Model
The growing attention on mechanisms that can provide predictability on interannual-to-decadal time scales, makes it necessary to identify how well climate models represent such mechanisms. In this study we use a high (0.25° horizontal grid) and a medium (1°) resolution version of a forced global ocean-sea ice model, utilising the Norwegian Earth System Model, to assess the impact of increased ocean resolution. Our target is the simulation of temperature and salinity anomalies along the pathway of warm Atlantic water in the subpolar North Atlantic and the Nordic Seas. Although the high resolution version has larger biases in general at the ocean surface, the poleward propagation of thermohaline anomalies is better resolved in this version, i.e., the time for an anomaly to travel northward is more similar to observation based estimates. The extent of these anomalies can be rather large in both model versions, as also seen in observations, e.g., stretching from Scotland to northern Norway. The easternmost branch into the Nordic and Barents Seas, carrying warm Atlantic water, is also improved by higher resolution, both in terms of mean heat transport and variability in thermohaline properties. A more detailed assessment of the link between the North Atlantic Ocean circulation and the thermohaline anomalies at the entrance of the Nordic Seas reveals that the high resolution is more consistent with mechanisms that are previously published. This suggests better dynamics and variability in the subpolar region and the Nordic Seas in the high resolution compared to the medium resolution. This is most likely due a better representation of the mean circulation in the studied region when using higher resolution. As the poleward propagation of ocean heat anomalies is considered to be a key source of climate predictability, we recommend that similar methodology presented herein should be performed on coupled climate models that are used for climate prediction.publishedVersio
A RESEARCH ON THE EFFECTS OF THE STORIES IN THE BOOK OF DEDE KORKUT ON SELF-ESTEEM
Benliğin oluşumunda kişinin fiziksel özellikleri, içinde doğduğu ve yetiştiği aile, aldığı eğitim, bağlı olduğu toplum gibi birçok kompleks yapının etkisi bulunmaktadır. Benlik saygısı zamanla inşa edilen, varlığını farklı dinamiklerin desteklediği bir sistemdir. Değişen değerler sistemi, gerçekleşen teknolojik yenilikler, hızla büyüyen şehirler, insanların benlik saygısını da ister istemez etkilemektedir. Kişinin hayattan zevk alması, motivasyonun yüksek olması, kendine güveni vb. için benlik saygısı olmazsa olmazıdır. Bu araştırmada Dede Korkut Kitabı’ndaki hikayelerin benlik saygısı üzerine etkisi ortaya konmaya çalışılacaktır. Millî hafızaya kazınan edebi eserler, toplumu yansıtırken aslında toplumu oluşturan bireyi yani kişisel “ben”i de aynalamaktadır. Bu araştırmada, bu akislerin fert üzerindeki etkisi anlamlandırılmaya çalışılmıştır. Çalışma için 18 Mart 2019-5 Nisan 2019 tarihlerinde 300 öğrenciye Rosenberg Benlik Saygısı Ölçeği uygulanmış ve düşük benlik saygısına sahip 16 denek tespit edilmiştir. 16 denekten 8’ine 8 Nisan 2019-17 Mayıs 2019 tarihlerinde yani 6 hafta süresince Dede Korkut Kitabı’ndan Dirse Han Oğlu Boğaç Han Destanı, Kam Püre’nin Oğlu Bamsı Beyrek Destanı, Kazan Bey Oğlu Uruz Bey’in Esir Olduğu Destanı, Duha Koca Oğlu Deli Dumrul Destanı, Kanglı Koca Oğlu Kan Turalı Destanı ve Begil Oğlu Emre’nin Destanı okunmuş ve tekrar Rosenberg Benlik Saygısı Ölçeği uygulanmıştır. Araştırmanın verileri SPSS 25.0 paket programı ile analiz edilmiştir. Elde edilen sonuçlara göre, Dede Korkut Kitabı’ndaki hikayelerin katılımcıların benlik saygısı üzerinde önemli bir etkisi olduğu bulunmuştur.Many complex structures such as the physical characteristics of the person, the family in which he was born and raised, the education he received, and the society he was affiliated with have influence on the formation of the self. Self-esteem is a system built over time and its existence is supported by different dynamics. The changing values system, technological innovations, and rapidly growing cities inevitably affect people's self-esteem. Self-esteem is a must for Enjoying life, high motivation, self-confidence, etc.. In this study, the effect of the stories in Dede Korkut Book on self-esteem is attempted to be revealed. While literary works engraved in the national memory reflect the society, they also mirror the individual “I” who forms the society. In this study, the effect of these flows on individuals was tried to be understood. To do this, Rosenberg Self-Esteem Scale was applied to 300 students between March 18, 2019 and April 5, 2019, and 16 subjects with low self-esteem were identified. Dirse Han Son Boğaç Han Epic, Kam Püre's Son Bamsı Beyrek Epic, Kazan Bey's Son Uruz Bey's Epic, Duha The Epic of Husband's Deli Dumrul, Kangli's Epic Blood Tail and Begil Son Emre's Epic from the Dede Korkut Book were read to 8 of 16 subjects between 8 April 2019 and 17 May 2019, for 6 weeks, and Rosenberg Self-Esteem Scale was applied again. The data were analyzed with SPSS 25.0 package program. According to the results obtained, the stories in Dede Korkut Book was found to have an important effect on the participants' self-esteemMany complex structures such as the physical characteristics of the person, the family in which he was born and raised, the education he received, and the society he was affiliated with have influence on the formation of the self. Self-esteem is a system built over time and its existence is supported by different dynamics. The changing values system, technological innovations, and rapidly growing cities inevitably affect people's self-esteem. Self-esteem is a must for Enjoying life, high motivation, self-confidence, etc.. In this study, the effect of the stories in Dede Korkut Book on self-esteem is attempted to be revealed. While literary works engraved in the national memory reflect the society, they also mirror the individual “I” who forms the society. In this study, the effect of these flows on individuals was tried to be understood. To do this, Rosenberg Self-Esteem Scale was applied to 300 students between March 18, 2019 and April 5, 2019, and 16 subjects with low self-esteem were identified. Dirse Han Son Boğaç Han Epic, Kam Püre's Son Bamsı Beyrek Epic, Kazan Bey's Son Uruz Bey's Epic, Duha The Epic of Husband's Deli Dumrul, Kangli's Epic Blood Tail and Begil Son Emre's Epic from the Dede Korkut Book were read to 8 of 16 subjects between 8 April 2019 and 17 May 2019, for 6 weeks, and Rosenberg Self-Esteem Scale was applied again. The data were analyzed with SPSS 25.0 package program. According to the results obtained, the stories in Dede Korkut Book was found to have an important effect on the participants' self-estee
Profile-encoding reconstruction for multiple-acquisition balanced steady-state free precession imaging
Purpose: The scan-efficiency in multiple-acquisition balanced steady-state free precession imaging can be maintained by accelerating and reconstructing each phase-cycled acquisition individually, but this strategy ignores correlated structural information among acquisitions. Here, an improved acceleration framework is proposed that jointly processes undersampled data across N phase cycles. Methods: Phase-cycled imaging is cast as a profile-encoding problem, modeling each image as an artifact-free image multiplied with a distinct balanced steady-state free precession profile. A profile-encoding reconstruction (PE-SSFP) is employed to recover missing data by enforcing joint sparsity and total-variation penalties across phase cycles. PE-SSFP is compared with individual compressed-sensing and parallel-imaging (ESPIRiT) reconstructions. Results: In the brain and the knee, PE-SSFP yields improved image quality compared to individual compressed-sensing and other tested methods particularly for higher N values. On average, PE-SSFP improves peak SNR by 3.8 ± 3.0 dB (mean ± s.e. across N = 2–8) and structural similarity by 1.4 ± 1.2% over individual compressed-sensing, and peak SNR by 5.6 ± 0.7 dB and structural similarity by 7.1 ± 0.5% over ESPIRiT. Conclusion: PE-SSFP attains improved image quality and preservation of high-spatial-frequency information at high acceleration factors, compared to conventional reconstructions. PE-SSFP is a promising technique for scan-efficient balanced steady-state free precession imaging with improved reliability against field inhomogeneity. Magn Reson Med 78:1316–1329, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicin
Description and evaluation of NorESM1-F: a fast version of the Norwegian Earth System Model (NorESM)
A new computationally efficient version of the Norwegian Earth System Model
(NorESM) is presented. This new version (here termed NorESM1-F) runs about
2.5 times faster (e.g., 90 model years per day on current hardware) than the
version that contributed to the fifth phase of the Coupled Model
Intercomparison project (CMIP5), i.e., NorESM1-M, and is therefore
particularly suitable for multimillennial paleoclimate and carbon cycle
simulations or large ensemble simulations. The speed-up is primarily a result
of using a prescribed atmosphere aerosol chemistry and a tripolar ocean–sea
ice horizontal grid configuration that allows an increase of the ocean–sea
ice component time steps. Ocean biogeochemistry can be activated for fully
coupled and semi-coupled carbon cycle applications. This paper describes the
model and evaluates its performance using observations and NorESM1-M as
benchmarks. The evaluation emphasizes model stability, important large-scale
features in the ocean and sea ice components, internal variability in the
coupled system, and climate sensitivity. Simulation results from NorESM1-F in
general agree well with observational estimates and show evident
improvements over NorESM1-M, for example, in the strength of the meridional
overturning circulation and sea ice simulation, both important metrics in
simulating past and future climates. Whereas NorESM1-M showed a slight global
cool bias in the upper oceans, NorESM1-F exhibits a global warm bias. In
general, however, NorESM1-F has more similarities than dissimilarities
compared to NorESM1-M, and some biases and deficiencies known in NorESM1-M
remain.</p
A new parameterization for entrainment in overflows
Author Posting. © American Meteorological Society, 2010. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 40 (2010): 1835–185, doi:10.1175/2010JPO4374.1.Dense overflows entrain surrounding waters at specific locations, for example, sills and constrictions, but also along the descent over the continental slope. The amount of entrainment dictates the final properties of these overflows, and thus is of fundamental importance to the understanding of the formation of deep water masses. Even when resolving the overflows, coarse resolution global circulation and climate models cannot resolve the entrainment processes that are often parameterized. A new empirical parameterization is suggested, obtained using an oceanic and laboratory dataset, which includes two novel aspects. First, the parameterization depends on both the Froude number (Fr) and Reynolds number of the flow. Second, it takes into account subcritical (Fr < 1) entrainment. A weak, but nonzero, entrainment can change the final density and, consequently, the depth and location of important water masses in the open ocean. This is especially true when the dense current follows a long path over the slope in a subcritical regime, as observed in the southern Greenland Deep Western Boundary Current. A streamtube model employing this new parameterization gives results that are more consistent with previous laboratory and oceanographic observations than when a classical parameterization is used. Finally, the new parameterization predictions compare favorably to recent oceanographic measurements of entrainment and turbulent diapycnal mixing rates, using scaling arguments to relate the entrainment ratio to diapycnal diffusivities.Support was given by the National Science Foundation
Project OCE-0350891 and OCE-0726339
Evaluation of NorESM-OC (versions 1 and 1.2), the ocean carbon-cycle stand-alone configuration of the Norwegian Earth System Model (NorESM1)
Idealised and hindcast simulations performed with the stand-alone ocean carbon-cycle configuration of the Norwegian Earth System Model (NorESM-OC) are described and evaluated. We present simulation results of two different model versions at different grid resolutions and using two different atmospheric forcing data sets. Model version NorESM-OC1 corresponds to the version that is included in the fully coupled model NorESM-ME1, which participated in CMIP5. The main update between NorESM-OC1 and NorESM-OC1.2 is the addition of two new options for the treatment of sinking particles. We find that using a constant sinking speed, which has been the standard in NorESM's ocean carbon cycle module HAMOCC (HAMburg Ocean Carbon Cycle model) does not transport enough particulate organic carbon (POC) into the deep ocean below approximately 2000 m depth. The two newly implemented parameterisations, a particle aggregation scheme with prognostic sinking speed, and a simpler scheme prescribing a linear increase of sinking speed with depth, provide better agreement with observed POC fluxes. Additionally, reduced deep ocean biases of oxygen and remineralised phosphate indicate a better performance of the new parameterisations. For model version 1.2, a re-tuning of the ecosystem parameterisation has been performed, which (i) reduces previously too high primary production in high latitudes, (ii) consequently improves model results for surface nutrients, and (iii) reduces alkalinity and dissolved inorganic carbon biases at low latitudes. We use hindcast simulations with prescribed observed and constant (pre-industrial) atmospheric CO2 concentrations to derive the past and contemporary ocean carbon sink. For the period 1990–1999 we find an average ocean carbon uptake ranging from 2.01 to 2.58 Pg C yr-1 depending on model version, grid resolution and atmospheric forcing data set
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