Showing papers by "Ludwig Maximilian University of Munich published in 2002"
TL;DR: In this article, taxonomies of different academic emotions and a self-report instrument measuring students' enjoyment, hope, pride, relief, anger, anxiety, shame, hopelessness, and boredom were developed.
Abstract: Academic emotions have largely been neglected by educational psychology, with the exception of test anxiety. In 5 qualitative studies, it was found that students experience a rich diversity of emotions in academic settings. Anxiety was reported most often, but overall, positive emotions were described no less frequently than negative emotions. Based on the studies in this article, taxonomies of different academic emotions and a self-report instrument measuring students' enjoyment, hope, pride, relief, anger, anxiety, shame, hopelessness, and boredom (Academic Emotions Questionnaire [AEQ]) were developed. Using the AEQ, assumptions of a cognitive-motivational model of the achievement effects of emotions, and of a control/value theory of their antecedents (Pekrun, 1992b, 2000), were tested in 7 cross-sectional, 3 longitudinal, and 1 diary study using samples of university and school students. Results showed that academic emotions are significantly related to students' motivation, learning strategies, cognit...
2,823 citations
TL;DR: The authors give a short overview of some propensity score matching estimators suggested in the evaluation literature, and provide a set of Stata programs, which they illustrate using the Naïve Bayes algorithm.
Abstract: In this paper, we give a short overview of some propensity score matching estimators suggested in the evaluation literature, and we provide a set of Stata programs, which we illustrate using the Na...
2,687 citations
TL;DR: Evidence is provided that PDC and B cells, but not monocytes, NK cells, or T cells, are primary targets of CpG ODN in peripheral blood.
Abstract: The Toll-like receptor (TLR)9 is critical for the recognition of immunostimulatory CpG motifs but may cooperate with other TLRs. We analyzed TLR1-10 mRNA expression by using quantitative real-time PCR in highly purified subsets of human PBMC and determined the sensitivity of these subsets to CpG oligodeoxynucleotides (ODN). TLR1 and TLR6 were expressed in all cell types examined. TLR10 was highly expressed in B cells and weakly expressed in plasmacytoid dendritic cells (PDC). High expression of TLR2 was characteristic for monocytes. PDC and B cells expressed marked levels of TLR7 and TLR9 and were directly sensitive to CpG ODN. In CpG ODN-stimulated PDC and B cells, TLR9 expression rapidly decreased, as opposed to TLR7, which was up-regulated in PDC and decreased in B cells. In monocytes, NK cells, and T cells, TLR7 was absent. Despite low expression of TLR9, monocytes, NK cells, and T cells did not respond to CpG ODN in the absence of PDC but were activated in the presence of PDC. In conclusion, our studies provide evidence that PDC and B cells, but not monocytes, NK cells, or T cells, are primary targets of CpG ODN in peripheral blood. The characteristic expression pattern of TLR1-10 in cellular subsets of human PBMC is consistent with the concept that TLR9 is essential in the recognition of CpG ODN in PDC and B cells. In addition, selective regulation of TLR7 expression in PDC and B cells by CpG ODN revealed TLR7 as a candidate TLR potentially involved in modulating the recognition of CpG motifs.
2,012 citations
TL;DR: It is estimated that between 0.81 and 2.57 Gt of carbon were released to the atmosphere in 1997 as a result of burning peat and vegetation in Indonesia, equivalent to 13–40% of the mean annual global carbon emissions from fossil fuels, and contributed greatly to the largest annual increase in atmospheric CO2 concentration detected since records began in 1957.
Abstract: Tropical peatlands are one of the largest near-surface reserves of terrestrial organic carbon, and hence their stability has important implications for climate change1,2,3. In their natural state, lowland tropical peatlands support a luxuriant growth of peat swamp forest overlying peat deposits up to 20 metres thick4,5. Persistent environmental change—in particular, drainage and forest clearing—threatens their stability2, and makes them susceptible to fire6. This was demonstrated by the occurrence of widespread fires throughout the forested peatlands of Indonesia7,8,9,10 during the 1997 El Nino event. Here, using satellite images of a 2.5 million hectare study area in Central Kalimantan, Borneo, from before and after the 1997 fires, we calculate that 32% (0.79 Mha) of the area had burned, of which peatland accounted for 91.5% (0.73 Mha). Using ground measurements of the burn depth of peat, we estimate that 0.19–0.23 gigatonnes (Gt) of carbon were released to the atmosphere through peat combustion, with a further 0.05 Gt released from burning of the overlying vegetation. Extrapolating these estimates to Indonesia as a whole, we estimate that between 0.81 and 2.57 Gt of carbon were released to the atmosphere in 1997 as a result of burning peat and vegetation in Indonesia. This is equivalent to 13–40% of the mean annual global carbon emissions from fossil fuels, and contributed greatly to the largest annual increase in atmospheric CO2 concentration detected since records began in 1957 (ref. 1).
1,731 citations
TL;DR: The methods for the determination of various types of oxygen surface functions on carbon materials are briefly described, and their relative advantages and problems that may arise are discussed in this paper, where acidimetric titration techniques, IR spectroscopy, XPS, thermal desorption spectroscopic, and electrokinetic measurements are described.
1,702 citations
TL;DR: Treatment of wild-type mice with the CB1 antagonist SR141716A mimicked the phenotype of CB1-deficient mice, revealing that CB1 is required at the moment of memory extinction, and proposes that endocannabinoids facilitate extinction of aversive memories through their selective inhibitory effects on local inhibitory networks in the amygdala.
Abstract: Acquisition and storage of aversive memories is one of the basic principles of central nervous systems throughout the animal kingdom. In the absence of reinforcement, the resulting behavioural response will gradually diminish to be finally extinct. Despite the importance of extinction, its cellular mechanisms are largely unknown. The cannabinoid receptor 1 (CB1) and endocannabinoids are present in memory-related brain areas and modulate memory. Here we show that the endogenous cannabinoid system has a central function in extinction of aversive memories. CB1-deficient mice showed strongly impaired short-term and long-term extinction in auditory fear-conditioning tests, with unaffected memory acquisition and consolidation. Treatment of wild-type mice with the CB1 antagonist SR141716A mimicked the phenotype of CB1-deficient mice, revealing that CB1 is required at the moment of memory extinction. Consistently, tone presentation during extinction trials resulted in elevated levels of endocannabinoids in the basolateral amygdala complex, a region known to control extinction of aversive memories. In the basolateral amygdala, endocannabinoids and CB1 were crucially involved in long-term depression of GABA (gamma-aminobutyric acid)-mediated inhibitory currents. We propose that endocannabinoids facilitate extinction of aversive memories through their selective inhibitory effects on local inhibitory networks in the amygdala.
1,641 citations
TL;DR: In this paper, the dephasing of particle plasmons was investigated using light-scattering spectroscopy on individual gold nanoparticles, and a drastic reduction of the plasmon de-phasing rate in nanorods as compared to small nanospheres due to a suppression of interband damping was found.
Abstract: The dephasing of particle plasmons is investigated using light-scattering spectroscopy on individual gold nanoparticles. We find a drastic reduction of the plasmon dephasing rate in nanorods as compared to small nanospheres due to a suppression of interband damping. The rods studied here also show very little radiation damping, due to their small volumes. These findings imply large local-field enhancement factors and relatively high light-scattering efficiencies, making metal nanorods extremely interesting for optical applications. Comparison with theory shows that pure dephasing and interface damping give negligible contributions to the total plasmon dephasing rate.
1,558 citations
TL;DR: Histone H3 methylated in vitro by the E(Z)/ESC complex binds specifically to Polycomb protein, which is closely associated with Polycomb binding sites on polytene chromosomes but is also found in centric heterochromatin, chromosome 4, and telomeric sites.
1,540 citations
TL;DR: It is shown that the performance of the new approaches to combining equalization based on linear filtering, with decoding is similar to the trellis-based receiver, while providing large savings in computational complexity.
Abstract: We study the turbo equalization approach to coded data transmission over channels with intersymbol interference. In the original system invented by Douillard et al. (1995), the data are protected by a convolutional code and the receiver consists of two trellis-based detectors, one for the channel (the equalizer) and one for the code (the decoder). It has been shown that iterating equalization and decoding tasks can yield tremendous improvements in bit error rate. We introduce new approaches to combining equalization based on linear filtering, with decoding.. Through simulation and analytical results, we show that the performance of the new approaches is similar to the trellis-based receiver, while providing large savings in computational complexity. Moreover, this paper provides an overview of the design alternatives for turbo equalization with given system parameters, such as the channel response or the signal-to-noise ratio.
1,271 citations
TL;DR: The radiative and nonradiative decay rates of lissamine dye molecules, chemically attached to differently sized gold nanoparticles, are investigated by means of time-resolved fluorescence experiments and theoretical results derived from the Gersten-Nitzan model are compared.
Abstract: The radiative and nonradiative decay rates of lissamine dye molecules, chemically attached to differently sized gold nanoparticles, are investigated by means of time-resolved fluorescence experiments. A pronounced fluorescence quenching is observed already for the smallest nanoparticles of 1 nm radius. The quenching is caused not only by an increased nonradiative rate but, equally important, by a drastic decrease in the dye’s radiative rate. Assuming resonant energy transfer to be responsible for the nonradiative decay channel, we compare our experimental findings with theoretical results derived from the Gersten-Nitzan model.
1,251 citations
TL;DR: Almost one fourth of patients with apparently sporadic pheochromocytoma may be carriers of mutations; routine analysis for mutations of RET, VHL, SDHD, and SDHB is indicated to identify pheosene-associated syndromes that would otherwise be missed.
Abstract: Background The group of susceptibility genes for pheochromocytoma that included the proto-oncogene RET (associated with multiple endocrine neoplasia type 2 [MEN-2]) and the tumor-suppressor gene VHL (associated with von Hippel–Lindau disease) now also encompasses the newly identified genes for succinate dehydrogenase subunit D (SDHD) and succinate dehydrogenase subunit B (SDHB), which predispose carriers to pheochromocytomas and glomus tumors. We used molecular tools to classify a large cohort of patients with pheochromocytoma with respect to the presence or absence of mutations of one of these four genes and to investigate the relevance of genetic analyses to clinical practice. Methods Peripheral blood from unrelated, consenting registry patients with pheochromocytoma was tested for mutations of RET, VHL, SDHD, and SDHB. Clinical data at first presentation and follow-up were evaluated. Results Among 271 patients who presented with nonsyndromic pheochromocytoma and without a family history of the disease,...
TL;DR: The results show that treatment with infliximab is effective in patients with active ankylosing spondylitis, and since there are some potentially serious adverse effects, it is recommended that this treatment mainly be used in co-operation with rheumatological centres.
TL;DR: It is found that TLR2 and TLR4 confer responsiveness to HSP70 in 293T fibroblasts and the expanding list of endogenous ligands able to activate the ancient Toll/IL-1 receptor signal pathway is in line with the “danger hypothesis” proposing that the innate immune system senses danger signals even if they originate from self.
TL;DR: Although the heterogeneous development of imatinib resistance is challenging, the fact that BCR-ABL is active in many resistant patients suggests that the chimeric oncoprotein remains a good therapeutic target.
Abstract: Selective inhibition of the BCR-ABL tyrosine kinase by imatinib (STI571, Glivec/Gleevec) is a promising new therapeutic strategy in patients with chronic myelogenous leukemia (CML). Despite significant hematologic and cytogenetic responses, resistance occurs, particularly in patients with advanced disease. We sought to determine the underlying mechanisms. Sixty-six patients with CML in myeloid blast crisis (n = 33), lymphoid blast crisis (n = 2), accelerated phase (n = 16), chronic phase (n = 13), and BCR-ABL-positive acute lymphoblastic leukemia (n = 2) resistant to imatinib were investigated. Median duration of imatinib therapy was 148 days (range 6-882). Patients were evaluated for genomic amplification of BCR-ABL, overexpression of BCR-ABL transcripts, clonal karyotypic evolution, and mutations of the imatinib binding site in the BCR-ABL tyrosine kinase domain. Results were as follows: (1) Median levels of BCR-ABL transcripts, were not significantly changed at the time of resistance but 7/55 patients showed a >10-fold increase in BCR-ABL levels; (2) genomic amplification of BCR-ABL was found in 2/32 patients evaluated by fluorescence in situ hybridization; (3) additional chromosomal aberrations were observed in 19/36 patients; (4) point mutations of the ABL tyrosine kinase domain resulting in reactivation of the BCR-ABL tyrosine kinase were detected in 23/66 patients. In conclusion, although the heterogeneous development of imatinib resistance is challenging, the fact that BCR-ABL is active in many resistant patients suggests that the chimeric oncoprotein remains a good therapeutic target. However, patients with clonal evolution are more likely to have BCR-ABL-independent mechanisms of resistance. The observations warrant trials combining imatinib with other agents.
TL;DR: The most frequent mutation in acute myeloid leukemia (AML) is the FLT3 length mutation (FLT3-LM) as discussed by the authors, which is a molecular marker potentially useful for the characterization of AML.
TL;DR: It is proposed that the PGR5 pathway contributes to the generation of a Delta(pH) that induces thermal dissipation when Calvin cycle activity is reduced, thus preventing photosystem I photoinhibition.
TL;DR: The targeting of enzymes that modulate the histone acetylation status of chromatin, in synergy with the effects mediated by other chromatin remodeling factors, is central to gene regulation.
Abstract: The organization of eukaryotic chromatin has a major impact on all nuclear processes involving DNA substrates. Gene expression is affected by the positioning of individual nucleosomes relative to regulatory sequence elements, by the folding of the nucleosomal fiber into higher-order structures and by the compartmentalization of functional domains within the nucleus. Because site-specific acetylation of nucleosomal histones influences all three aspects of chromatin organization, it is central to the switch between permissive and repressive chromatin structure. The targeting of enzymes that modulate the histone acetylation status of chromatin, in synergy with the effects mediated by other chromatin remodeling factors, is central to gene regulation.
TL;DR: Recent progress is summarized in the understanding of the mechanisms underlying the nucleosome remodeling reaction, the targeting of remodeling machines to selected sites in chromatin, and their integration into complex regulatory schemes.
Abstract: It has been a long-standing challenge to decipher the principles that enable cells to both organize their genomes into compact chromatin and ensure that the genetic information remains accessible to regulatory factors and enzymes within the confines of the nucleus. The discovery of nucleosome remodeling activities that utilize the energy of ATP to render nucleosomal DNA accessible has been a great leap forward. In vitro, these enzymes weaken the tight wrapping of DNA around the histone octamers, thereby facilitating the sliding of histone octamers to neighboring DNA segments, their displacement to unlinked DNA, and the accumulation of patches of accessible DNA on the surface of nucleosomes. It is presumed that the collective action of these enzymes endows chromatin with dynamic properties that govern all nuclear functions dealing with chromatin as a substrate. The diverse set of ATPases that qualify as the molecular motors of the nucleosome remodeling process have a common history and are part of a superfamily. The physiological context of their remodeling action builds on the association with a wide range of other proteins to form distinct complexes for nucleosome remodeling. This review summarizes the recent progress in our understanding of the mechanisms underlying the nucleosome remodeling reaction, the targeting of remodeling machines to selected sites in chromatin, and their integration into complex regulatory schemes.
TL;DR: It is argued that social norms of traditional masculinity make help-seeking more difficult because of the inhibition of emotional expressiveness influencing symptom perception of depression.
TL;DR: Ten linking rules are developed and an example of their use are presented to provide a systematic and standardized approach when linking health-status measures to the International Classification of Functioning, Disability and Health.
Abstract: With the approval of the International Classification of Functioning, Disability and Health by the World Health Assembly in May 2001, the concurrent use of both health-status measures and the International Classification of Functioning, Disability and Health is expected. It is therefore important to understand the relationship between these two concepts. The objective of this paper is to provide a systematic and standardized approach when linking health-status measures to the International Classification of Functioning, Disability and Health. The specific aims are to develop rules, to test their reliability and to illustrate these rules with examples. Ten linking rules and an example of their use are presented in this paper. The percentage agreement between two health professionals for 8 health-status instruments tested is also presented. A high level of agreement between the health professionals reflects that the linking rules established in this study allow the sound linking of items from health-status measures to the International Classification of Functioning, Disability and Health.
TL;DR: Cognitive behavioural therapy (CBT) and other variants of behaviour therapy have been sufficiently investigated in controlled studies in patients with anxiety disorders, OCD, and PTSD to support them being recommended either alone or in combination with the above medicines.
Abstract: SummaryIn this report, recommendations for the pharmacological treatment of anxiety and obsessive-compulsive disorders are presented, based on available randomized, placebo-or comparator-controlled
TL;DR: The high mortality rate among critically ill patients with acute renal failure who require renal-replacement therapy is related to both coexisting conditions and uremic damage to other organ systems.
Abstract: Background Intermittent hemodialysis is widely used as renal-replacement therapy in patients with acute renal failure, but an adequate dose has not been defined. We performed a prospective study to determine the effect of daily intermittent hemodialysis, as compared with conventional (alternate-day) intermittent hemodialysis, on survival among patients with acute renal failure. Methods A total of 160 patients with acute renal failure were assigned to receive daily or conventional intermittent hemodialysis. Survival was the primary end point of the study. The duration of acute renal failure and the frequency of therapy-related complications were secondary end points. Results The two study groups were similar with respect to age, sex, cause and severity of acute renal failure, medical or surgical intensive care setting, and the score on the Acute Physiology, Age, and Chronic Health Evaluation. Daily hemodialysis resulted in better control of uremia, fewer hypotensive episodes during hemodialysis, and more r...
TL;DR: The polymer was found to contract against an external force acting along the polymer backbone, thus delivering mechanical work, demonstrating for the first time optomechanical energy conversion in a single-molecule device.
Abstract: Light-powered molecular machines are conjectured to be essential constituents of future nanoscale devices As a model for such systems, we have synthesized a polymer of bistable photosensitive azobenzenes Individual polymers were investigated by single-molecule force spectroscopy in combination with optical excitation in total internal reflection We were able to optically lengthen and contract individual polymers by switching the azo groups between their trans and cis configurations The polymer was found to contract against an external force acting along the polymer backbone, thus delivering mechanical work As a proof of principle, the polymer was operated in a periodic mode, demonstrating for the first time optomechanical energy conversion in a single-molecule device
TL;DR: This work presents the extension UMLsec of UML that allows to express securityrelevant information within the diagrams in a system specification, and gives criteria to evaluate the security aspects of a system design, by referring to a formal semantics of a simplified UML.
Abstract: Developing secure-critical systems is difficult and there are many well-known examples of security weaknesses exploitedin practice. Thus a sound methodology supporting secure systems development is urgently needed.Our aim is to aid the difficult task of developing security-critical systems in an approach basedon the notation of the Unified Modeling Language. We present the extension UMLsec of UML that allows to express securityrelevant information within the diagrams in a system specification. UMLsec is defined in form of a UML profile using the standard UML extension mechanisms. In particular, the associatedc onstraints give criteria to evaluate the security aspects of a system design, by referring to a formal semantics of a simplifiedfragm ent of UML. We demonstrate the concepts with examples.
TL;DR: The extracorporeally induced destruction of kidney stones was used successfully in all patients with stones in the renal pelvis and in none of these patients was an open operation required.
TL;DR: In this paper, the authors investigated how gender inequality in education affects long-term economic growth and found that such inequality has an effect on economic growth that is robust to changes in specifications and controls for potential endogeneities.
Abstract: Using cross-country and panel regressions, this article investigates how gender inequality in education affects long-term economic growth. Such inequality is found to have an effect on economic growth that is robust to changes in specifications and controls for potential endogeneities. The results suggest that gender inequality in education directly affects economic growth by lowering the average level of human capital. In addition, growth is indirectly affected through the impact of gender inequality on investment and population growth. Some 0.4-0.9 percentage points of differences in annual per capita growth rates between East Asia and Sub-Saharan Africa, South Asia, and the Middle East can be accounted for by differences in gender gaps in education between these regions.
TL;DR: JAM-1 is a counter-receptor for LFA-1 that is ideally situated to guide and control transmigration during leukocyte recruitment and is also a ligand of the β2 integrin lymphocyte function–associated antigen 1.
Abstract: Inflammatory recruitment of leukocytes is governed by dynamic interactions between integrins and endothelial immunoglobulin superfamily (IgSF) proteins. We have identified the IgSF member junctional adhesion molecule 1 (JAM-1) as a ligand of the beta(2) integrin lymphocyte function-associated antigen 1 (LFA-1). Under static and physiological flow conditions, JAM-1 contributed to LFA-1-dependent transendothelial migration of T cells and neutrophils as well as LFA-1-mediated arrest of T cells. The latter was triggered by chemokines on endothelium that was stimulated with cytokines to redistribute JAM-1 from the tight junctions. Transfectants expressing JAM-1 supported LFA-1-mediated adhesion of leukocytes, which required the membrane-proximal Ig-like domain 2 of JAM-1. Thus, JAM-1 is a counter-receptor for LFA-1 that is ideally situated to guide and control transmigration during leukocyte recruitment.
TL;DR: This work investigated the patterns of genetic variation along a recombining chromosome by constructing ancestral recombination graphs that are modified to incorporate the effect of genetic hitchhiking, and proposed a statistical method to test the significance of a local reduction of variation and a skew of the frequency spectrum caused by a hitchhiker event.
Abstract: The theory of genetic hitchhiking predicts that the level of genetic variation is greatly reduced at the site of strong directional selection and increases as the recombinational distance from the site of selection increases. This characteristic pattern can be used to detect recent directional selection on the basis of DNA polymorphism data. However, the large variance of nucleotide diversity in samples of moderate size imposes difficulties in detecting such patterns. We investigated the patterns of genetic variation along a recombining chromosome by constructing ancestral recombination graphs that are modified to incorporate the effect of genetic hitchhiking. A statistical method is proposed to test the significance of a local reduction of variation and a skew of the frequency spectrum caused by a hitchhiking event. This method also allows us to estimate the strength and the location of directional selection from DNA sequence data.
TL;DR: In severe ischemic heart failure, MRI hyperenhancement as a marker of myocardial scar closely agrees with PET data, and it seems to identify scar tissue more frequently than PET, reflecting the higher spatial resolution.
Abstract: Background — Recent studies indicate that MRI, after administration of gadolinium-diethylenetriamine pentaacetic acid, can identify nonviable areas in dysfunctional myocardium. We compared MRI hyperenhancement with PET as a gold standard for detection and quantification of myocardial scar tissue. Methods and Results — Thirty-one patients with ischemic heart failure (ejection fraction, 28±9%) were imaged with PET and MRI. Scar was defined as regionally increased MRI signal intensity 20 minutes after injection of 0.2 mmol/kg gadolinium-diethylenetriamine pentaacetic acid and as concordantly reduced perfusion and glucose metabolism as defined by PET. Sensitivity and specificity of MRI in identifying patients and segments (n=1023) with matched flow/metabolism defects was 0.96 of 1.0 and 0.86 of 0.94, respectively. Eleven percent of segments defined as viable by PET showed some degree of MRI hyperenhancement. Defect severity score based on visual analysis was 44.3±9.1 for PET and 47.6±11.1 for MRI ( r =0.91, P r =0.81, P Conclusions — In severe ischemic heart failure, MRI hyperenhancement as a marker of myocardial scar closely agrees with PET data. Although hyperenhancement correlated with areas of decreased flow and metabolism, it seems to identify scar tissue more frequently than PET, reflecting the higher spatial resolution. Additional functional studies after revascularization are required to define the significance of small islands of scar detected by MRI.
TL;DR: Experimental evidence suggests three major mechanisms of action of UDCA, which may improve serum liver chemistries, delay disease progression to severe fibrosis or cirrhosis, and may prolong transplant‐free survival in primary biliary Cirrhosis and primary sclerosing cholangitis.