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Search Results: 1 - 10 of 4835 matches for " Bj?rn Fritz "
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Infinitary Axiomatization of the Equational Theory of Context-Free Languages
Niels Bjrn Bugge Grathwohl,Fritz Henglein,Dexter Kozen
Computer Science , 2013, DOI: 10.4204/EPTCS.126.4
Abstract: We give a natural complete infinitary axiomatization of the equational theory of the context-free languages, answering a question of Lei{\ss} (1992).
Application of Pedagogical Perspectives in the Teaching and Training of New Cataract Surgeons—A Literature-Based Essay  [PDF]
Bjrn Johansson
Open Journal of Ophthalmology (OJOph) , 2013, DOI: 10.4236/ojoph.2013.33015

Cataract is the most common cause of visual impairment that can be effectively treated by surgery and cataract surgery is the most commonly performed surgical procedure in the world. With modern cataract operation techniques, patients expect excellent results. Teaching and training of new surgeons involve both pedagogical and ethical challenges for teachers and trainees, and also may pose a potential risk to patients. This literature-based essay aims to describe how behavioristic, cognitive and conceptual learning perspectives can be recognized during the trainee surgeons progress. It also describes how teacher-pupil relationships may vary during the training process. Finally it presents the concept of situational tutorship, where the teacher adapts to the stages that the trainee passes through with increasing experience. Teaching and trainee surgeons who are aware of pedagogical concepts such as teacher-pupil relationships and tutoring strategies may use this knowledge to optimize the learning process. Further research is needed to clarify how using this knowledge may affect the training of new cataract surgeons.

Limited Focus on the Use of Health Care by Elderly Migrants—A Literature Review  [PDF]
Katarina Hjelm, Bjrn Albin
Open Journal of Nursing (OJN) , 2014, DOI: 10.4236/ojn.2014.46049

Our premise for this literature review is the global demographic change caused by the world’s population living longer and becoming older, and extensive international migration leading to multicultural societies. Increasing age leads to health problems, often long-term or chronic, requiring investments in health care. Worse health and dissimilarities in pattern of morbidity/ mortality have been found in foreign-compared to Swedish-born persons, so it is reasonable to assume that this affects use of health care. The exploratory review focuses on elderly migrants’ (>65 years) use of healthcare. The databases Pub Med, EBSCO, CINAHL and ERIC were searched in 2000-2013. A limited number of studies were found; few had a comparative approach, most were from the USA, and focused on migrants from the former Soviet Union or countries in South-East Asia. A range of factors were identified that influence patterns of health care use: language fluency, ability to communicate, self-reported health status, prevalence of chronic disease, physical distance from care provision, availability of transport to reach care, cost of care, the health insurance system, cultural norms and values regarding different forms of care, level of education, and length of residence in the host country. Most studies treated health care from a general perspective and collected data from community and hospital settings, without analysing usage separately. Some studies indicated elderly migrants making use of health care less than other groups but the pattern is not unambiguous: other studies show that there is an overuse of health care. It is therefore difficult to show any particular pattern, or possible differences in use, regarding community versus in-patient care. Studies focusing on migrants’ actual use of health care are few and further research is needed, especially because elderly people form the largest group of users of health care and will be even larger in the future.

Co-localization of CENP-C and CENP-H to discontinuous domains of CENP-A chromatin at human neocentromeres
Alicia Alonso, Bjrn Fritz, Dan Hasson, Gy?rgy Abrusan, Fanny Cheung, Kinya Yoda, Bernhard Radlwimmer, Andreas G Ladurner, Peter E Warburton
Genome Biology , 2007, DOI: 10.1186/gb-2007-8-7-r148
Abstract: We have examined the distribution of CENP-A, as well as two additional centromeric chromatin-associated proteins (CENP-C and CENP-H), across neocentromeric DNA using chromatin immunoprecipitation (ChIP) on CHIP assays on custom genomic microarrays at three different resolutions. Analysis of two neocentromeres using a contiguous bacterial artificial chromosome (BAC) microarray spanning bands 13q31.3 to 13q33.1 shows that both CENP-C and CENP-H co-localize to the CENP-A chromatin domain. Using a higher resolution polymerase chain reaction (PCR)-amplicon microarray spanning the neocentromere, we find that the CENP-A chromatin is discontinuous, consisting of a major domain of about 87.8 kilobases (kb) and a minor domain of about 13.2 kb, separated by an approximately 158 kb region devoid of CENPs. Both CENP-A domains exhibit co-localization of CENP-C and CENP-H, defining a distinct inner kinetochore chromatin structure that is consistent with higher order chromatin looping models at centromeres. The PCR microarray data suggested varying density of CENP-A nucleosomes across the major domain, which was confirmed using a higher resolution oligo-based microarray.Centromeric chromatin consists of several CENP-A subdomains with highly discontinuous CENP-A chromatin at both the level of individual nucleosomes and at higher order chromatin levels, raising questions regarding the overall structure of centromeric chromatin.The centromere, which is the chromosome component that is responsible for the proper segregation of sister chromatids to daughter cells during cell division, is a specialized chromatin structure [1,2]. Centromeric chromatin has a distinctive nucleosome structure that contains the histone H3 variant centromere protein (CENP)-A [3-8]. CENP-A containing chromatin associates with a large number of proteins, which are assembled in a hierarchical manner [9-12]. Essential among the proximal proteins are several associated with the centromere throughout the cell cycle,
Macrophage cholesterol efflux correlates with lipoprotein subclass distribution and risk of obstructive coronary artery disease in patients undergoing coronary angiography
Patrick Linsel-Nitschke, Henning Jansen, Zouhair Aherrarhou, Stefanie Belz, Bjrn Mayer, Wolfgang Lieb, Fritz Huber, Werner Kremer, Hans-Robert Kalbitzer, Jeanette Erdmann, Heribert Schunkert
Lipids in Health and Disease , 2009, DOI: 10.1186/1476-511x-8-14
Abstract: Monocytes isolated from blood samples of patients scheduled for cardiac catheterization were differentiated into macrophages over seven days. Isotopic cholesterol efflux to exogenously added apolipoprotein A-I and HDL2 was measured. Quantitative cholesterol efflux from macrophages was correlated with lipoprotein subclass distribution in plasma from the same individuals measured by NMR-spectroscopy of lipids and with the extent of coronary artery disease seen on coronary angiography.Macrophage cholesterol efflux was positively correlated with particle concentration of smaller HDL and LDL particles but not with total plasma concentrations of HDL or LDL-cholesterol. We observed an inverse relationship between macrophage cholesterol efflux and the concntration of larger and triglyceride rich particles (VLDL, chylomicrons). Subjects with significant stenosis on coronary angiography had lower cholesterol efflux from macrophages compared to individuals without significant stenosis (adjusted p = 0.02).Macrophage cholesterol efflux is inversely correlated with lipoprotein particle size and risk of CAD.The excessive uptake of lipoproteins by cells in the arterial wall gives rise to cholesterol-loaded cells with foamy cytoplasm due to the presence of cholesteryl ester droplets known as foam cells. These foam cells form the hallmark of atherosclerotic plaques. The efflux of cholesterol from foam cells is mediated by high-density lipoprotein (HDL) or its apolipoproteins and is widely believed to represent a crucial step in the prevention or reversal of atherosclerosis [1]. Macrophage cholesterol efflux has been proposed as the initial step in the reverse cholesterol transport (RCT), a prominent hypothesis to explain the anti-atherogenic mechanisms of HDL [2]. Although for many years the efllux of cholesterol was thought to occur primarily by passive aqueous diffusion, recently it has become clear that cholesterol efflux from macrophages is a highly regulated process that is medi
Concealed Integrity Monitoring for Wireless Sensor Networks  [PDF]
Bjrn Stelte, Thomas Bühring
Wireless Sensor Network (WSN) , 2011, DOI: 10.4236/wsn.2011.31002
Abstract: Nowadays, sensor networks are widely installed around the world. Typical sensors provide data for healthcare, energy management, environmental monitoring, etc. In the future sensors will become a part of critical infrastructures. In such a scenario the network operator has to monitor the integrity of the network devices, otherwise the trustworthiness of the whole system is questionable. The problem is that every integrity protocol needs a secure channel between the devices. Therefore, we will introduce a covert channel for hidden transportation of integrity monitoring messages. The covert channel enables us to hide integrity check messages embedded into regular traffic without giving potential attackers a hint on the used integrity protocol.
Diversity in Family Structure—Diversity in Communication between Family Members?  [PDF]
Piia M. Bjrn, Minna Kytt?l?
Psychology (PSYCH) , 2013, DOI: 10.4236/psych.2013.43A035

This study aims at investigating the parent-adolescent communication of Finnish families from a multi informant perspective. Thirteen- and fourteen-year-old adolescents (n = 171) and their parents were asked to complete a questionnaire examining positive and problematic communication between the two parties. Information about their family structure was collected. The results indicated an interrelationship between parental and adolescent assessments, particularly regarding negative aspects of communication. The boys assessed their communication with parents as more positive than did the girls. The results showed that the mothers still are the synchronizing hearts of communication in modern families, whereas the fathers’ roles in family communication were more modest suggesting that the stereotypical roles in Finnish families persist even today.

Spatial Competition between Health Care Providers: Effects of Standardization  [PDF]
Bjrn A. Kuchinke, Jürgen Zerth
Theoretical Economics Letters (TEL) , 2015, DOI: 10.4236/tel.2015.53043
Abstract: In the international health care literature the impacts of competition in health care markets are discussed widely. But aspects of standardization in regional health care markets with no price competition received comparatively little attention. We use a typical Hotelling framework to analyze a regional health care market with two health care providers competing in (vertical) quality after the scope of medical treatment has been set (horizontal quality). We conclude that in the basic model both health care providers will use vertical quality to separate from each other. In the next step we introduce a standard in vertical quality of which one health care providerthe standard profiteer—could better cope with. In the standardization case a more homogeneous supply can be expected and there is a higher possibility that the standard follower has to leave the regional health care market. Therefore standardization of health care quality could strengthen monopolistic tendencies.
Structures and Styles of Deformation in Rift, Ridge, Transform Zone, Oblique Rift and a Microplate Offshore/Onshore North Iceland  [PDF]
Maryam Khodayar, Sveinbj?rn Bj?rnsson
International Journal of Geosciences (IJG) , 2018, DOI: 10.4236/ijg.2018.98029
Abstract: The diverging plate boundaries in North Iceland and its shelf display a complex tectonic at the Kolbeinsey Ridge (K-R), the Northern Rift Zone (NRZ), and the Tj?rnes Fracture Zone containing the Grímsey Oblique Rift (GOR), the Húsavík-Flatey Fault (HFF), and the Dalvík Lineament (DL). While active deformation is well-known, the structural pattern is sporadically mapped and a comprehensive account of the upper Tertiary-present deformation is not fully at hand. To address the gaps, this paper provides new regional tectonic maps with continuous coverage, and detailed analyses of the deformation. Faults, open fractures, prominent joints and volcanic edifices were identified on Multibeam/Single beam, Spot 5, and Digital Elevation Model, and subjected to multidisciplinary structural analysis and correlation with selected data. Some of the results are: 1) Six sets constitute the structural pattern. The N-S rift-parallel normal faults are 1/3, and the shear fractures of the transform zone and the oblique rift 2/3 of the fracture population. The en échelon arrangements above deep-seated shear zones indicate dextral slip on WNW to NW, and sinistral slip on NNE to ENE faults, conformable with earthquake data. 2) During the polyphase tectonic, the six sets led to basin and horst formation, block compartmentalisation, rotation, horsetail splay, rhomb-graben in relay zone of strike-slips, and volcanism. 3) Listric faults are absent and the steeply-dipping faults are antithetic, synthetic, or form extensional flower structures above 4 km depth. The Plio-pleistocene/present syn-sedimentary deformation caused a deep half graben in the Eyjafjarearáll Basin (Ey), fault growth, rollover, and sediment onlaps, with some of the faults still active. 4) The plate boundaries of K-R/Ey, GOR/?xarfjreur/NRZ, and DL delimit a major microplate labelled here as Grímsey-Tj?rnes-Dalvík. 5) The WNW earthquake cluster in GOR corresponds either to a blind horsetail splay fault or to initiation of a transform segment parallel to the HFF. The described tectonic-sedimentary-magmatic deformation is relevant to other diverging plate boundaries where similar sets control the hydrocarbon and geothermal resources.
Obstacle and Dirichlet problems on arbitrary nonopen sets, and fine topology
Anders Bjrn,Jana Bjrn
Mathematics , 2012, DOI: 10.4171/RMI/830
Abstract: We study the double obstacle problem for p-harmonic functions on arbitrary bounded nonopen sets E in quite general metric spaces. The Dirichlet and single obstacle problems are included as special cases. We obtain Adams' criterion for the solubility of the single obstacle problem and establish connections with fine potential theory. We also study when the minimal p-weak upper gradient of a function remains minimal when restricted to a nonopen subset. Most of the results are new for open E (apart from those which are trivial in this case) and also on R^n.
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