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Effects of Fewer Students
No full textDie Zahl der Studierenden hat in Deutschland ihren Höhepunkt überschritten und dürfte zukünftig weiter abnehmen wie schon länger die Jahrgangsstärke und inzwischen auch die Studierneigung. Für die Hochschulen verschärft das den Wettbewerb und sie müssen sich vermehrt um ihre aktuellen und zukünftigen Studierenden bemühen. Die Studierenden profitieren davon, doch politisch schwindet ihr Einfluss und drohen Kürzungen der staatlichen Mittel für Hochschulen, die deshalb effizienter eingesetzt werden sollten.The number of students in Germany has passed its peak and is likely to continue to fall in the
future, as has been the case for some time with the number of students per year and now also
with the willingness to study. This means that competition is increasing for universities and
they have to make more efforts to attract their current and future students. The students bene-
fit from this, but politically their influence is waning and there is a threat of cuts in state fund-
ing for universities, which should therefore be used more efficiently
Smiths Münzen:Grundlegungen zur Hermeneutisch-Explorativen Gedankenexperimentation
No full textDie herkömmliche Gedankenexperimentation in der Philosophie läuft unreguliert ab und erfährt inner- und interdisziplinäre Kritik und Ablehnung. Dass dasselbe Gedankenexperiment Nutzer zu unterschiedlichen Ergebnissen führen kann, stellt dabei die Reproduzierbarkeit der Ergebnisse dieser Methode infrage. Die Untersuchung erwägt Möglichkeiten methodologischer Optimierung. Aus der Erfassung des Angebots zur Theorie des Gedankenexperiments (nach 1980) und aus einer Untersuchung der zeitgenössischen gedankenexperimentellen Praxis werden bestehende Probleme auf beiden Ebenen ermittelt. Es wird ein Anwendungsmodell für gedankenexperimentelle Szenarien entwickelt, das die identifizierten Probleme weitestgehend vermeiden kann. Aus der Feststellung, dass es sich bei den Methodenoptimierungen um Kommunikationsmaßnahmen handelt, wird eine Kommunikationstheorie der Gedankenexperimentation und eine Narrationstheorie des Gedankenexperiments entwickelt. Wer gedankenexperimentiert, kommuniziert. Hauptkommunikationsmittel sind kleine Narrationen: die Gedankenexperimente
Spatiotemporal wavevector dynamics of transverse mode-locked beams
No full textThe phase-locking of transverse higher-order resonator modes results in a beam with rapidly oscillating spatial intensity profile. To complete the description of such transverse mode-locked (TML) beams, their spatiotemporal phase dynamics are explored in this work. The analysis of the phase terms of TML beams reveals oscillating wavevectors, which are experimentally verified by exploiting the mode-matching requirement of a single-mode fiber. The wavevector oscillation is further quantified by exploring its dependence on beam size. The findings have to be considered in potential future applications of TML beams in phase-sensitive processes
Spectral library and method for sparse unmixing of hyperspectral images in fluorescence guided resection of brain tumors
No full textThrough spectral unmixing, hyperspectral imaging (HSI) in fluorescence-guided brain tumor surgery has enabled the detection and classification of tumor regions invisible to the human eye. Prior unmixing work has focused on determining a minimal set of viable fluorophore spectra known to be present in the brain and effectively reconstructing human data without overfitting. With these endmembers, non-negative least squares regression (NNLS) was commonly used to compute the abundances. However, HSI images are heterogeneous, so one small set of endmember spectra may not fit all pixels well. Additionally, NNLS is the maximum likelihood estimator only if the measurement is normally distributed, and it does not enforce sparsity, which leads to overfitting and unphysical results. In this paper, we analyzed 555666 HSI fluorescence spectra from 891 ex vivo measurements of patients with various brain tumors to show that a Poisson distribution indeed models the measured data 82% better than a Gaussian in terms of the Kullback-Leibler divergence, and that the endmember abundance vectors are sparse. With this knowledge, we introduce (1) a library of 9 endmember spectra, including PpIX (620 nm and 634 nm photostates), NADH, FAD, flavins, lipofuscin, melanin, elastin, and collagen, (2) a sparse, non-negative Poisson regression algorithm to perform physics-informed unmixing with this library without overfitting, and (3) a highly realistic spectral measurement simulation with known endmember abundances. The new unmixing method was then tested on the human and simulated data and compared to four other candidate methods. It outperforms previous methods with 25% lower error in the computed abundances on the simulated data than NNLS, lower reconstruction error on human data, better sparsity, and 31 times faster runtime than state-of-the-art Poisson regression. This method and library of endmember spectra can enable more accurate spectral unmixing to aid the surgeon better during brain tumor resection
Visual perceptual load and processing of somatosensory stimuli in primary and secondary somatosensory cortices
No full text'Load theory' assumes that neural activation to distractors in early sensory cortices is modulated by the perceptual load of a main task, regardless of whether task and distractor share the same sensory modality or not. While several studies have investigated the question of load effects on distractor processing in early sensory areas, there is no functional magnetic resonance imaging (fMRI) study regarding load effects on somatosensory stimuli. Here, we used fMRI to investigate effects of visual perceptual load on neural responses to somatosensory stimuli applied to the wrist in a study with 44 participants. Perceptual load was manipulated by an established sustained visual detection task, which avoided simultaneous target and distractor presentations. Load was operationalized by detection difficulty of subtle or clear color changes of one of 12 rotating dots. While all somatosensory stimuli led to activation in somatosensory areas SI and SII, we found no statistically significant difference in brain activation to these stimuli under high compared to low sustained visual load. Moreover, exploratory Bayesian analyses supported the absence of differences. Thus, our findings suggest a resistance of somatosensory processing to at least some forms of visual perceptual load, possibly due to behavioural relevance of discrete somatosensory stimuli and separable attentional resources for the somatosensory and visual modality
Economic Ethical Considerations on Climate Change
No full textNaturwissenschaftliche Fragen rund um den Klimawandel sind von Naturwissenschaftlern zu beantworten. Ökonomen und Wirtschaftsethiker können jedoch dazu beitragen, den Klimawandel und mögliche Gegenmaßnahmen zu bewerten. Dabei ist ein einheitlicher Preis für die Emission von Treibhausgasen zu empfehlen. Es gibt ein globales Kollektivgutproblem, welches sich am ehesten durch die Vereinbarung einer Zertifikatslösung überwinden lässt. Außerdem sollten die Forschung und Entwicklung gefördert werden.Natural scientific questions regarding climate change have to be answered by natural scientist. However, economists and economic ethicists can contribute to the evaluation of climate change and possible countermeasures. In doing so, a uniform price for the emission of greenhouse gases is advisable. There is a global public good problem that can most likely be resolved by the agreement of a certificate solution. Moreover, research and development should be supported
A Non-Canonical and Genetically Encoded Amino Acid for Chemical Manipulation of Proteins and Unnatural Enzymatic Catalysis in Living Cells
No full textIm Rahmen dieser Dissertation wurde eine Erweiterung des genetischen Codes durch eine neuartige unnatürliche Aminosäure untersucht. Die entwickelte unnatürliche Aminosäure HcyX ist chemisch entschützbar und kann mittels Nonsense Suppression in Proteine eingebaut werden. Durch die geschützte Seitenkette ist die Thiolgruppe aus Homocystein nicht funktional, kann jedoch durch Phosphin-Reagenzien oder bioorthogonal mittels trans-Cycloocten freigelegt werden. So konnte die spezifische Modifikation und chemische Kontrolle von Proteinen erzielt werden. Die Aktivität von Proteinen konnte unter anderem durch die Schützung von aktiven Zentren durch HcyX reguliert werden. Erstmals ist der Ersatz einer katalytischen Aminosäure -wie von Serin oder Cystein- durch Homocystein gelungen, sodass die Regulation von organismischem Wachstum vermittelt durch die unnatürliche Aminosäure gezeigt werden konnte.This dissertation investigated the expansion of the genetic code using a novel unnatural amino acid. The developed unnatural amino acid, HcyX, is chemically deprotectable and can be incorporated into proteins by nonsense suppression. Due to the protected side chain, the thiol group of homocysteine is non-functional, but can be exposed using phosphine reagents or bioorthogonally by using trans-cyclooctene. This enabled the specific modification and chemical control of proteins. Protein activity was regulated, among other things, by HcyX protecting active sites. For the first time, the replacement of a catalytic amino acid -such as serine or cysteine- with homocysteine has been successful, thus demonstrating the regulation of organismic growth mediated by the unnatural amino acid
Enhancing Volume Precision in Breast Reconstruction: A BMI-Based Model for Predicting Flap Weight in Profunda Artery Perforator Flaps
No full textBackground: In recent years, the profunda artery perforator (PAP) flap has gained recognition as a viable technique in autologous breast reconstruction, demonstrating low donor site morbidity and favorable reconstructive outcomes. This study aims to highlight the recent refinements using the PAP flap for breast reconstruction focusing on preoperative volume prediction. Methods: A retrospective study was conducted to evaluate the outcomes of breast reconstruction surgeries using the PAP flap at our institution between May 2018 and December 2022. A total of 114 PAP flaps performed in 96 patients were included. Statistical analysis was performed to analyze flap volume in relation to body mass index (BMI). Surgical details, such as donor site-related complications and patient characteristics, were also collected. Results: BMI was identified as a statistically significant predictor (p < 0.001) for flap weight in the resulting model. The average BMI observed was 23.0, while the mean flap weight was 304.2 g. The predictive model for flap weight was determined as follows: flap weight (g) = (19.252 × BMI) − 143.572. This model underscores the relationship between BMI and flap weight, quantifying the influence of BMI on flap weight prediction. Conclusions: Our study indicates that it is feasible to harvest an adequate volume for breast reconstruction even in patients with a low BMI. To facilitate preoperative prediction of PAP flap volume, we developed an algorithm designed to enhance preoperative planning and estimate the need for supplementary procedures to achieve the desired volume
Ethylene Production in the Petrochemical Industry: Competitive Risks and Impacts of the EU Emission Trading Scheme
No full textThe European petrochemical industry is facing significant challenges that threaten its global competitiveness. Key challenges are the rising energy costs and a global increase in overcapacity for critical petrochemical building blocks, including ethylene, propylene, butadiene, benzene, mixed xylol, and toluene (Berry C., 2024). The European Union Emissions Trading Scheme (EU ETS), established with the aim to facilitate the reduction of greenhouse gas emissions in the face of climate change, also imposes further economic burdens on the industry. European emitters must purchase CO2 allowances (EUAs), while the Carbon Boarder Adjustment Mechanism (CBAM) does not provide full compensation for imports of chemicals from non-EU countries, exacerbating competitive disadvantages. This study conducts a comparative analysis of the competitiveness between the EU and the US in 2023, focusing on naphtha- and ethane-based steam cracking. The calculation of variable production costs for 2023 shows a competitive disadvantage for EU producers, with variable production costs in Europe being 380 higher per ton compared to the US. The situation is further exacerbated by the cost of EUAs, which could increase production costs by up to 11.5% by 2030. The introduction of the EUAs for European CO2 emitters without cost compensation by considering imports via the CBAM leads to a further deterioration of the competitive situation. EUAs costs could represent up to 11.5% of variable production costs by 2030, depending on the technology and forecast. This study highlights the compounded impact of rising production costs and environmental regulations on the competitiveness of European ethylene production