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Search Results: 1 - 10 of 706 matches for " Gunter Schumann "
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Early rectal stenosis following stapled rectal mucosectomy for hemorrhoids
Sven Petersen, Gunter Hellmich, Dietrich Schumann, Anja Schuster, Klaus Ludwig
BMC Surgery , 2004, DOI: 10.1186/1471-2482-4-6
Abstract: A retrospective analysis of 419 consecutive patients, which underwent SRM from December 1998 to August 2003 was performed. Only patients with at least one follow-up check were evaluated, thus the analysis includes 289 patients with a mean follow-up of 281 days (±18 days).For statistic analysis the groups with and without stenosis were evaluated using the Chi-Square Test, using the Kaplan-Meier statistic the actuarial incidence for rectal stenosis was plotted.Rectal stenosis was observed in 9 patients (3.1%), eight of these stenoses were detected within the first 100 days after surgery; the median time to stenosis was 95 days. Only one patient had a rectal stenosis after more than one year. 8 of the 9 patients had no obstructive symptoms, however the remaining patients complained of obstructive defecation and underwent surgery for transanal strictureplasty with electrocautery. A statistical analysis revealed that patients with stenosis had significantly more often prior treatment for hemorrhoids (p < 0.01). According to the SRM only severe postoperative pain was significantly associated with stenoses (p < 0.01). Other factors, such as gender (p = 0.11), surgical technique (p = 0.25), revision (p = 0.79) or histological evidence of squamous skin (p = 0.69) showed no significance.Rectal stenosis is an uncommon event after SRM. Early stenosis will occur within the first three months after surgery. The majority of the stenoses are without clinical relevance. Only one of nine patients had to undergo surgery for a relevant stenosis. The predictive factor for stenosis in the patient-characteristics is previous interventions for hemorrhoids, severe postoperative pain might also predict rectal stenosis.Within the last years, stapled rectal mucosectomy (SRM) has become a widely accepted procedure for second and third degree hemorrhoids. In comparison to conventional hemorrhoidectomy, the reduction of postoperative pain and the shorter hospital stay made SRM a recommended surgi
Schwarzschild Geodesics in Terms of Elliptic Functions and the Related Red Shift  [PDF]
Gunter Scharf
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.24036
Abstract: Using Weierstrassian elliptic functions the exact geodesics in the Schwarzschild metric are expressed in a simple and most transparent form. The results are useful for analytical and numerical applications. For example we calculate the perihelion precession and the light deflection in the post-Einsteinian approximation. The bounded orbits are computed in the post-Newtonian order. As a topical application we calculate the gravitational red shift for a star moving in the Schwarzschild field.
Nucleotide Sequence Variation within the PI3K p85 Alpha Gene Associates with Alcohol Risk Drinking Behaviour in Adolescents
Sylvane Desrivières, Kristina Krause, Anne Dyer, Josef Frank, Dorothea Blomeyer, Mark Lathrop, Karl Mann, Tobias Banaschewski, Manfred Laucht, Gunter Schumann
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001769
Abstract: Background While the phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathway is typically known to regulate cell growth and survival, emerging evidence suggest a role for this pathway in regulating the behavioural responses to addictive drugs. Methodology/Principal Findings To investigate whether PI3K contributes to patterns of risky alcohol drinking in human, we investigated genetic variations in PIK3R1, encoding the 85 kD regulatory subunit of PIK, in 145 family trios consisting of 15–16 year old adolescents and their parents. Screening for mutations in exons, exon-intron boundaries and regulatory sequences, we identified 14 single nucleotide polymorphisms (SNPs) in the PIK3R1 gene region from exon 1 to the beginning of the 3′ untranslated region (UTR). These SNPs defined haplotypes for the respective PIK3R1 region. Four haplotype tagging (ht)SNPs (rs706713, rs2302975, rs171649 and rs1043526), discriminating all haplotypes with a frequency ≥4.5% were identified. These htSNPs were used to genotype adolescents from the “Mannheim Study of Risk Children” (MARC). Transmission disequilibrium tests in these adolescents and their parents demonstrated sex-specific association of two SNPs, rs2302975 and rs1043526, with patterns of risky alcohol consumption in male adolescents, including lifetime prevalence of drunkenness (p = 0.0019 and 0.0379, respectively) and elevated maximum amount of drinking (p = 0.0020 and 0.0494, respectively), as a measure for binge drinking pattern. Conclusions/Significance Our findings highlight a previously unknown relevance of PIK3R1 genotypes for alcohol use disorders and might help discriminate individuals at risk for alcoholism.
Beyond Patient Reported Pain: Perfusion Magnetic Resonance Imaging Demonstrates Reproducible Cerebral Representation of Ongoing Post-Surgical Pain
Matthew A. Howard,Kristina Krause,Nadine Khawaja,Nathalie Massat,Fernando Zelaya,Gunter Schumann,John P. Huggins,William Vennart,Steven C. R. Williams,Tara F. Renton
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017096
Abstract: Development of treatments for acute and chronic pain conditions remains a challenge, with an unmet need for improved sensitivity and reproducibility in measuring pain in patients. Here we used pulsed-continuous arterial spin-labelling [pCASL], a relatively novel perfusion magnetic-resonance imaging technique, in conjunction with a commonly-used post-surgical model, to measure changes in regional cerebral blood flow [rCBF] associated with the experience of being in ongoing pain. We demonstrate repeatable, reproducible assessment of ongoing pain that is independent of patient self-report. In a cross-over trial design, 16 participants requiring bilateral removal of lower-jaw third molars underwent pain-free pre-surgical pCASL scans. Following extraction of either left or right tooth, repeat scans were acquired during post-operative ongoing pain. When pain-free following surgical recovery, the pre/post-surgical scanning procedure was repeated for the remaining tooth. Voxelwise statistical comparison of pre and post-surgical scans was performed to reveal rCBF changes representing ongoing pain. In addition, rCBF values in predefined pain and control brain regions were obtained. rCBF increases (5–10%) representing post-surgical ongoing pain were identified bilaterally in a network including primary and secondary somatosensory, insula and cingulate cortices, thalamus, amygdala, hippocampus, midbrain and brainstem (including trigeminal ganglion and principal-sensory nucleus), but not in a control region in visual cortex. rCBF changes were reproducible, with no rCBF differences identified across scans within-session or between post-surgical pain sessions. This is the first report of the cerebral representation of ongoing post-surgical pain without the need for exogenous tracers. Regions of rCBF increases are plausibly associated with pain and the technique is reproducible, providing an attractive proposition for testing interventions for on-going pain that do not rely solely on patient self-report. Our findings have the potential to improve our understanding of the cerebral representation of persistent painful conditions, leading to improved identification of specific patient sub-types and implementation of mechanism-based treatments.
Association of PER2 Genotype and Stressful Life Events with Alcohol Drinking in Young Adults
Dorothea Blomeyer, Arlette F. Buchmann, Jesus Lascorz, Ulrich S. Zimmermann, Günter Esser, Sylvane Desrivieres, Martin H. Schmidt, Tobias Banaschewski, Gunter Schumann, Manfred Laucht
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0059136
Abstract: Background Clock genes govern circadian rhythms and shape the effect of alcohol use on the physiological system. Exposure to severe negative life events is related to both heavy drinking and disturbed circadian rhythmicity. The aim of this study was 1) to extend previous findings suggesting an association of a haplotype tagging single nucleotide polymorphism of PER2 gene with drinking patterns, and 2) to examine a possible role for an interaction of this gene with life stress in hazardous drinking. Methods Data were collected as part of an epidemiological cohort study on the outcome of early risk factors followed since birth. At age 19 years, 268 young adults (126 males, 142 females) were genotyped for PER2 rs56013859 and were administered a 45-day alcohol timeline follow-back interview and the Alcohol Use Disorders Identification Test (AUDIT). Life stress was assessed as the number of severe negative life events during the past four years reported in a questionnaire and validated by interview. Results Individuals with the minor G allele of rs56013859 were found to be less engaged in alcohol use, drinking at only 72% of the days compared to homozygotes for the major A allele. Moreover, among regular drinkers, a gene x environment interaction emerged (p = .020). While no effects of genotype appeared under conditions of low stress, carriers of the G allele exhibited less hazardous drinking than those homozygous for the A allele when exposed to high stress. Conclusions These findings may suggest a role of the circadian rhythm gene PER2 in both the drinking patterns of young adults and in moderating the impact of severe life stress on hazardous drinking in experienced alcohol users. However, in light of the likely burden of multiple tests, the nature of the measures used and the nominal evidence of interaction, replication is needed before drawing firm conclusions.
Monitoring Land-Use Change in Nakuru (Kenya) Using Multi-Sensor Satellite Data  [PDF]
Kenneth Mubea, Gunter Menz
Advances in Remote Sensing (ARS) , 2012, DOI: 10.4236/ars.2012.13008
Abstract:

Recently land-use change has been the main concern for worldwide environment change and is being used by city and regional planners to design sustainable cities. Nakuru in the central Rift Valley of Kenya has undergone rapid urban growth in last decade. This paper focused on urban growth using multi-sensor satellite imageries and explored the potential benefits of combining data from optical sensors (Landsat, Worldview-2) with Radar sensor data from Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data for urban land-use mapping. Landsat has sufficient spectral bands allowing for better delineation of urban green and impervious surface, Worldview-2 has a higher spatial resolution and facilitates urban growth mapping while PALSAR has higher temporal resolution compared to other operational sensors and has the capability of penetrating clouds irrespective of weather conditions and time of day, a condition prevalent in Nakuru, because it lies in a tropical area. Several classical and modern classifiers namely maximum likelihood (ML) and support vector machine (SVM) were applied for image classification and their performance assessed. The land-use data of the years 1986, 2000 and 2010 were compiled and analyzed using post classification comparison (PCC). The value of combining multi-temporal Landsat imagery and PALSAR was explored and achieved in this research. Our research illustrated that SVM algorithm yielded better results compared to ML. The integration of Landsat and ALOS PALSAR gave good results compared to when ALOS PAL- SAR was classified alone. 19.70 km2 of land changed to urban land-use from non-urban land-use between the years 2000 to 2010 indicating rapid urban growth has taken place. Land-use information is useful for the comprehensive land-use planning and an integrated management of resources to ensure sustainability of land and to achieve social Eq- uity, economic efficiency and environmental sustainability.

 

Spatial Effects of Varying Model Coefficients in Urban Growth Modeling in Nairobi, Kenya  [PDF]
Kenneth Mubea, Gunter Menz
Journal of Geographic Information System (JGIS) , 2014, DOI: 10.4236/jgis.2014.66053
Abstract: Urban land-use modeling has gained increased attention as a research topic over the last decade. This has been attributed to advances in remote sensing and computing technology that now can process several models simultaneously at regional and local levels. In this research we implemented a cellular automata (CA) urban growth model (UGM) integrated in the XULU modeling frame-work (eXtendable Unified Land Use Modeling Platform). We used multi-temporal Landsat satellite image sets for 1986, 2000 and 2010 to map urban land-use in Nairobi. We also tested the spatial effects of varying model coefficients. This approach improved model performance and aided in understanding the particular urban land-use system dynamics operating in our Nairobi study area. The UGM was calibrated for Nairobi and predicted development was derived for the city for the year 2030 when Kenya plans to attain Vision 2030. Observed land-use changes in urban areas were compared to the results of UGM modeling for the year 2010. The results indicate that varying the UGM model coefficients simulates urban growth in different directions and magnitudes. This approach is useful to planners and policy makers because the model outputs can identify specific areas within the urban complex which will require infrastructure and amenities in order to realize sustainable development.
Extended Correlations in Finance  [PDF]
Mark Burgin, Gunter Meissner
Journal of Mathematical Finance (JMF) , 2016, DOI: 10.4236/jmf.2016.61017
Abstract:

Extended correlations, i.e. correlations that can take values less than − 1?and/or larger than 1, occur naturally in mathematical models of financial processes. Extended correlations also occur in financial practice, especially in dispersion trading, implying arbitrage opportunities. Based on theoretical and practical emergence of extended correlations, we derive a mathematical framework for extended correlations explaining interpretations and applications. We develop a broader mathematical approach, which can model conventional as well as extended correlations.

1 + 1 = 3: Synergy Arithmetic in Economics  [PDF]
Mark Burgin, Gunter Meissner
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.82011
Abstract: Counting has always been one of the most important operations for human be-ings. Naturally, it is inherent in economics and business. We count with the unique arithmetic, which humans have used for millennia. However, over time, the most inquisitive thinkers have questioned the validity of standard arithmetic in certain settings. It started in ancient Greece with the famous philosopher Zeno of Elea, who elaborated a number of paradoxes questioning popular knowledge. Millennia later, the famous German researcher Herman Helmholtz (1821-1894) [1] expressed reservations about applicability of conventional arithmetic with respect to physical phenomena. In the 20th and 21st century, mathematicians such as Yesenin-Volpin (1960) [2], Van Bendegem (1994) [3], Rosinger (2008) [4] and others articulated similar concerns. In validation, in the 20th century expressions such as 1 + 1 = 3 or 1 + 1 = 1 occurred to reflect important characteristics of economic, business, and social processes. We call these expressions synergy arithmetic. It is common notion that synergy arithmetic has no meaning mathematically. However in this paper we mathematically ground and explicate synergy arithmetic.
Affiliation of Dihydrolipoyl Dehydrogenase Allozymes in Mycorrhizae of European Forest Trees and Characterization of the Enzyme of the Matt Bolete (Xerocomus pruinatus) and the Bay Bolete (X. badius)  [PDF]
Uwe Schirkonyer, Gunter M. Rothe
Open Journal of Ecology (OJE) , 2018, DOI: 10.4236/oje.2018.86022
Abstract: Mycorrhizal roots of the deciduous trees European beech (Fagus sylvatica (L.)) and Sessile oak (Quercus petraea (MattuschkaLiebl.)) and the conifers Norway spruce (Picea abies (L.) H. Karst.) and European larch (Larix decidua (Mill.)) associated with the ectomycorrhizal fungi matt bolete (Xerocomus pruinatus (Fries 1835)) or bay bolete (X. badius (Fries 1818)) were analysed with respect to the occurrence of dihydrolipoyl dehydrogenase (EC 1.8.1.4) allozymes. In root tissues of the two deciduous trees, two gene loci could be visualized after cellulose acetate electrophoresis while three loci were expressed in root tissues of the two coniferous species. The two fungal species and further ectomycorrhizal fungi expressed exclusively one dihydrolipoyl dehydrogenase gene. In Xerocomus pruinatus and X. badius, the dihydrolipoyl dehydrogenase gene consists of 1460 bp and 1370 bp, respectively, including five introns each consisting of 52 bp. Their DNA sequences correspond to 70 to 90% to other fungal dihydrolipoyl dehydrogenase genes. One monomer of the dimeric dihydrolipoyl dehydrogenase enzyme consists of 486 (X. pruinatus) or 454 (X.
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