Search results for "IFA"
showing 10 items of 620 documents
Automated detection of patient movement during a CBCT scan based on the projection data.
2015
Objectives To develop an automated procedure to detect patient motion on the projection images acquired during a cone beam computed tomography (CBCT) scan and to evaluate the method's feasibility on small real-world CBCT images in relation to visual assessment. Methods Based on optical flow theory, software was developed using the sequence of the projection images of a CBCT machine for automated detection of patient motion. Averaged acceleration vectors were used as measurement data and compared with visual assessment of the projection images displayed as video. Seventy-nine CBCT data sets (small field-of-view: 40 mm) from our patient database were selected in a sequential fashion and evalu…
Metal artifact reduction in x-ray computed tomography: Inpainting versus missing value
2011
A comparison of algorithms for reduction of metal artifacts in x-ray cone beam computed tomography (CBCT) is presented. In the context of algebraic reconstruction techniques (ART) several inpainting algorithms in the image domain are evaluated against missing data strategies. A GPU-based iterative framework is employed for a meaningful comparison of both. Simulation results from an extended Shepp-Logan phantom and real world dental data are given.
On cone-beam computed tomography artifacts induced by titanium implants
2010
Objectives: To briefly review the mathematical background of beam-hardening artifacts in cone-beam computed tomography (CBCT)-reconstruction and to investigate geometrical properties relevant for these reconstruction errors. By means of simulated and experimental results, beam-hardening effects caused by titanium implants are evaluated. Materials and methods: The geometrical and physical properties of the acquisition process of the projections used for 3D reconstruction are investigated and their effects on the CBCT images in the presence of titanium implants are derived. Beam-hardening effects are computed for a simplified polychromatic situation (three energy subsets of 80 and 110 kV) and…
Motion Artifact Detection in Confocal Laser Endomicroscopy Images
2018
Confocal Laser Endomicroscopy (CLE), an optical imaging technique allowing non-invasive examination of the mucosa on a (sub)- cellular level, has proven to be a valuable diagnostic tool in gastroenterology and shows promising results in various anatomical regions including the oral cavity. Recently, the feasibility of automatic carcinoma detection for CLE images of sufficient quality was shown. However, in real world data sets a high amount of CLE images is corrupted by artifacts. Amongst the most prevalent artifact types are motion-induced image deteriorations. In the scope of this work, algorithmic approaches for the automatic detection of motion artifact-tainted image regions were develo…
Climate mitigation and intensified forest management in Norway: To what extent are surface waters safeguarded?
2020
AbstractWhile the role of forestry in mitigating climate change is increasingly subject to political commitment, other areas, such as water protection, may be at risk. In this study, we ask whether surface waters are sufficiently safeguarded in relation to the 2015 launch of a series of measures to intensify forest management for mitigation of climate change in Norway. First, we assess how impacts on water are accounted for in existing regulations for sustainable forestry. Secondly, we provide an overview of the impacts of forestry on water quality relevant to three support schemes: afforestation on new areas, increased stocking density in existing forests, and forest fertilisation. Lastly,…
Protection from fishing improves body growth of an exploited species
2022
Hunting and fishing are often size-selective, which favours slow body growth. In addition, fast growth rate has been shown to be positively correlated with behavioural traits that increase encounter rates and catchability in passive fishing gears such as baited traps. This harvest-induced selection should be effectively eliminated in no-take marine-protected areas (MPAs) unless strong density dependence results in reduced growth rates. We compared body growth of European lobster ( Homarus gammarus ) between three MPAs and three fished areas. After 14 years of protection from intensive, size-selective lobster fisheries, the densities in MPAs have increased considerably, and we demonstrate t…
Stabilizing selection on Atlantic cod supergenes through a millennium of extensive exploitation
2022
Life on Earth has been characterized by recurring cycles of ecological stasis and disruption, relating biological eras to geological and climatic transitions through the history of our planet. Due to the increasing degree of ecological abruption caused by human influences many advocate that we now have entered the geological era of the Anthropocene, or “the age of man.” Considering the ongoing mass extinction and ecosystem reshuffling observed worldwide, a better understanding of the drivers of ecological stasis will be a requisite for identifying routes of intervention and mitigation. Ecosystem stability may rely on one or a few keystone species, and the loss of such species could potentia…
Samtidskunst i skolen : En studie som inviterer elever til en konseptuell workshopspraksis
2019
Masteroppgave kunstfag KF500 - Universitetet i Agder 2019 Both from the elementary school education and the professional life, I have gained insight and an experience basis for commenting on the subject of arts and crafts. There are often techniques and crafts that are in focus. I miss howthe subject to a greater extentcanchallengestudent`s in critical thinking, playful exploration and reflection, especially with regards to visual art. This master thesis focuses on theseperspectives for teaching in the subject arts and crafts, and discuss contemporary art's place intheschool. The thesis can be viewed as a post in the discourse about the new curriculumforarts and crafts, scheduledtobe comple…
Ruolo dei parassitoidi oofagi nel controllo naturale dei fitofagi del nocciolo responsabili del “cimiciato delle nocciole” nel Parco dei Nebrodi (ME).
2009
Role of oophagous parasitoids in the natural control of hazelnut bugs inducing the “cimiciato seeds” in Nebrodi Park (ME) Oophagous parasitoids of bugs collected on hazelnut cultivations and seasonal parasitism on eggs of Gonocerus acutengulatus (Goeze) were studied from 2004 to 2006 in the Nebrodi Park (ME). Samples of bug eggs were collected in three altitude areas, 300-590, 600-890 and 900-1100 m above sea level, and examined in laboratory. Parasitoid adults obtained from all eggs were identified. Parasitization levels, detected on G. acuteangulatus in all areas showed a similar trend with the most value on August. Significant regression between the total number of eggs and the number of…
Rationale and evidence on the use of tocilizumab in COVID-19: a systematic review
2020
Abstract Background Tocilizumab is an IL-6 receptor-blocking agent proposed for the treatment of severe COVID-19. The aim of this systematic review was to describe the rationale for the use of tocilizumab for the treatment of COVID-19 and to summarize the available evidence regarding its efficacy and safety. Methods MEDLINE, PubMed, EMBASE, pre-print repositories (bioRxiv and medRxiv) and two trial Registries were searched for studies on the use of tocilizumab in COVID-19 or SARS-CoV-2 infection, viral pneumonia, and/or sepsis until 20th June 2020. Results We identified 3 indirect pre-clinical studies and 28 clinical studies including 5776 patients with COVID-19 (13 with a comparison group,…