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Colonial injustices under international law: a study of the 1904-1908 Herero/Nama genocide
No full textThe Herero/Nama genocide of 1904-1908 is indeed a sad chapter in the Namibian history. It is often described by historians as the first genocide of the 20th century similar or worse in scope to the Armenian genocide of World War I. The genocide resulted in the displacement and almost the obliteration of the Herero and Nama ethnic groups who resided in the territory of the then German South West Africa. Although it is widely accepted that the order for the extermination of these two groups was made by General Lothar von Trotha who was resident in the territory at the time, there exists evidence that there was tacit approval from the Kaiser’s government which gave the greenlight for the genocide to begin. However, little literature exists on the impact of the genocide on the socio-economic conditions of the affected communities and Namibia in general. This chapter departs with the assumption that Namibia is among the most unequal countries in the world partly due to its colonial history. This assumption is supported by scholars who posit that the population displacement, confiscation of cattle and land by the German colonial authorities impoverished the Ovaherero and Nama communities – thereby exacerbating the disparities and inequality in the Namibian society. The legacy of Germany’s colonial rule still reverberates today. The most arable land in Namibia today is in the hands of white farmers of mostly German descent. Therefore, this chapter aims to investigate the legacies of colonialism and their effects in Namibia. In addition, the chapter makes postulations on strategies that may be adopted, including reparations from Germany, to alleviate the current palatable socio-economic conditions and other political problems afflicting Namibia
The reference window for reduced perturbation of the reference wave in electrical biasing off-axis electron holography
No full textThe perturbation of the reference wave due to electric stray fields represents a major challenge in quantitative electron holographic investigations. By introducing a focused-ion-beam-milled rectangular hole, the reference window, in an area of nearly constant electrostatic potential of the sample, this perturbation can be significantly reduced. The edge of the window forms a closed conducting loop, acting similarly to a Faraday cage, shielding the influence of the stray field on the reference wave to some extent. In this work, the shielding effect of the reference window is systematically investigated by comparing electron holograms of an electrically biased coplanar capacitor, as a well-known reference sample, with finite element simulations. It is shown that the introduction of the reference window into electrical biasing samples both suppresses unknown lateral phase distortions substantially and in addition improves the agreement of the experimentally observed phase slope with that expected by simulation significantly, particularly for small object-reference wave distances. Consequently, a slight adjustment of the sample geometry results in an improved reproducibility of electron holographic electrical biasing experiments, which is a significant step towards quantitative evaluation.Peer Reviewe
A stochastic population model for the impact of cancer cell dormancy on therapy success
No full textTherapy evasion – and subsequent disease progression – is a major challenge in current oncology. An important role in this context seems to be played by various forms of cancer cell dormancy. For example, therapy-induced dormancy, over short timescales, can create serious obstacles to aggressive treatment approaches such as chemotherapy, and long-term dormancy may lead to relapses and metastases even many years after an initially successful treatment. In this paper, we focus on individual cancer cells switching into and out of a dormant state both spontaneously as well as in response to treatment. We introduce an idealized mathematical model, based on stochastic agent-based interactions, for the dynamics of cancer cell populations involving individual short-term dormancy, and allow for a range of (multi-drug) therapy protocols. Our analysis – based on simulations of the many-particle limit – shows that in our model, depending on the specific underlying dormancy mechanism, even a small initial population (of explicitly quantifiable size) of dormant cells can lead to therapy failure under classical single-drug treatments that would successfully eradicate the tumour in the absence of dormancy. We further investigate and quantify the effectiveness of several multi-drug regimes (manipulating dormant cancer cells in specific ways, including increasing or decreasing resuscitation rates or targeting dormant cells directly). Relying on quantitative results for concrete simulation parameters, we provide some general basic rules for the design of (multi-)drug treatment protocols depending on the types and processes of dormancy mechanisms present in the population.Peer Reviewe
A comparative analysis with psychedelic-using and non-using controls
No full textThe article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Classic psychedelics like LSD and psilocybin are showing promising effects in treating certain psychiatric disorders. Despite their low toxicity and lack of an addictive potential, in some individuals, psychedelics can be associated with persisting psychological harms. Hallucinogen Persisting Perception Disorder (HPPD) is one of those complications, a rare disorder characterized by enduring perceptual symptoms without impaired reality control. While the phenomenological aspects of HPPD have been characterized, the neuropsychological consequences have remained understudied. This study probes the neuropsychological profiles of eight individuals with HPPD, utilizing a comprehensive test battery. Performance is benchmarked against normative data and compared with two control groups, each comprising eight matched subjects—with and without prior psychedelic use. The assessment of individual performances revealed below average results in tests of visual memory and executive function in some subjects. No significant differences were observed in alpha-adjusted comparisons with controls, whereas unadjusted analyses were suggestive of impaired executive functions among HPPD patients. Together, these preliminary results underline the need for further focused research into the neuropsychological dimensions of HPPD.Peer Reviewe
Innervation pattern and fiber counts of the human dorsal nerve of clitoris
No full textThe article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Even tough clitoris plays a critical role in female sexuality, we lack a precise understanding of qualitative and quantitative aspects of the innervation of the human clitoris. To address this issue, we dissected human clitorides from body donors and imaged them after staining with iodine with microCT for a macroscopic analysis. To resolve innervation patterns at the microscopic level we prepared thin sections of clitorides and stained them with trichrome azan to reveal the tissue structure combined with immunocytochemistry against Neurofilament H antibodies to reveal all axons and luxol blue labeling to reveal myelinated axons. We find the clitoral branch of pudendal nerve that innervates the clitoris not as single nerve, but as number of loose bundles. In the crus of the clitoris, about 12 such bundles can be recognized while about 32 bundles are present in the clitoral hemi-body. We counted on avarage 2917 axons in the crus of the clitoris (76% of which are myelinated) and 3137 axons in the hemibody of the clitoris (71% of which are myelinated). While the human clitoris receives only one third of the number of axons that innervate the human penis, an estimate of innervation density (per surface area) revealed that clitoris has approximately 6 times denser innervation compared to the penis. Thus, our study combines histology with microCT analysis provides detailed information on the number, myelination and innervation density of dorsal nerve of clitoris.Peer Reviewe
Does electoral behavior change after a protest cycle? Evidence from Chile and Bolivia
No full textCan protests produce changes in electoral behavior? In this paper, we examine variations in voter turnout and electoral preferences at the local level after a protest cycle. Using data on protest occurrence during the 2019 social mobilizations in Chile and Bolivia and a difference-in-differences design, we assess the impact that street demonstrations had on voting behavior in the elections that took place the following year. We found that turnout was higher in municipalities that had protests, while the incumbent vote was lower. We argue that the effect on turnout is explained by the surge in political efficacy that emerged from the protests. Furthermore, we suggest that the protests enabled more effective blame attribution and heightened the salience of political issues, leading to changes in voter preferences. These results demonstrate the effect of protests on electoral dynamics, highlighting their role not only in mobilizing voters but also in shaping electoral preferences.Peer Reviewe
The impact of dormancy on evolutionary branching
No full textIn this paper, we investigate the consequences of dormancy in the ‘rare mutation’ and ‘large population’ regime of stochastic adaptive dynamics. Starting from an individual-based micro-model, we first derive the Polymorphic Evolution Sequence of the population, based on a previous work by Baar and Bovier (2018). After passing to a second ‘small mutations’ limit, we arrive at the Canonical Equation of Adaptive Dynamics, and state a corresponding criterion for evolutionary branching, extending a previous result of Champagnat and Méléard (2011).The criterion allows a quantitative and qualitative analysis of the effects of dormancy in the well-known model of Dieckmann and Doebeli (1999) for sympatric speciation. In fact, quite an intuitive picture emerges: Dormancy enlarges the parameter range for evolutionary branching, increases the carrying capacity and niche width of the post-branching sub-populations, and, depending on the model parameters, can either increase or decrease the ‘speed of adaptation’ of populations. Finally, dormancy increases diversity by increasing the genetic distance between subpopulations.Peer Reviewe
Food choice and pharyngeal pumping activity of bacterial-feeding nematodes are driven by different functional traits
No full textThe feeding behavior of free-living nematodes is shaped by several factors, including food choice and food consumption. The latter is commonly investigated by determining the pumping rate of the pharynx. However, whether the pharyngeal pumping activity also reflects food selection, i.e. whether the pumping rate for preferred food is increased, is largely unknown. The aim of this study was to investigate the relation between pumping rate and food choice. For this, the preference of the nematodes Diploscapter coronatus, Diploscapter pachys, Plectus similis and Plectus sp. were examined in binary choice assays. The bacteria Bacillus subtilis, Kitasatospora sp., Sphingomonas trueperi, Pseudomonas fluorescens and two Legionella pneumophila strains were tested against Escherichia coli OP50. The nematode pumping rates were determined for each bacterial diet. Additionally, the effects of bacterial species and size, and of nematode species and genus, size of buccal cavity and pharynx morphology, were investigated. The nematodes showed a preference for P. fluorescens (except D. pachys) and avoidance of B. subtilis, Kitasatospora sp. and L. pneumophila. The determinants of food choice were nematode species, bacterial species and size, while the pumping rates varied with genus and pharynx proportion. The food preference determined by the choice assay was not necessarily associated with an upregulation of pharyngeal pumping, e.g. Plectus preferred P. fluorescens over E. coli OP50 when having a choice but pumped significantly faster when feeding on the latter. Although the pumping rate changed with bacterial species, there was no clear pattern that allowed a correlation with food choice across the tested nematode taxa, suggesting that pumping frequency is no indicator for food preference. Relating these results to nematode foraging strategy, food choice was determined by bacterial traits associated with diet quality and search, while food consumption was linked to nematode traits affecting diet handling.Peer Reviewe
Activation of SO2F2 at a Rhodium PNP Pincer Complex: Ligand Supported S−F Bond Cleavage to Generate NSO2F Derivatives
No full textThe κ2‐(P,N)−phosphine ligand precursor NH(CH2CH2PCy2)2 can be used for the synthesis of the rhodium(I) complex [Rh(CO){ĸ3-(P,N,P)−Cy2PC2H4NHC2H4PCy2}][Cl] (1). The deprotonated complex [Rh(CO){ĸ3‐(P,N,P)−Cy2PC2H4NC2H4PCy2}] (2) shows a cooperative reactivity of the PNP ligand in the activation reaction of SO2F2 to yield the rhodium fluorido complex trans‐[Rh(F)(CO){ĸ2‐(P,P)−Cy2PC2H4N(SO2F)C2H4PCy2}]2 (3) by S−F bond cleavage. It is remarkable that no reaction was observed when 3 was treated with hydrogen sources e. g. dihydrogen, organosilicon compounds such as triethylsilane or TMS−CF3 and different fluorine sources such as SF4 or Selectfluor®. However, the treatment of complex 3 with XeF2 in the presence of CsF resulted in the formation of the unique fluorido rhodium(III) complex cis,trans‐[Rh(F)3(CO){ĸ2‐(P,P)−Cy2PC2H4N(SO2F)C2H4PCy2}]2 (4). In the presence of pyridine(HF)X or BF3 the fluorido complex 3 converted into the dicationic complexes [Rh(CO){ĸ2‐(P,P)−Cy2PC2H4N(SO2F)C2H4PCy2}]2[XF]2, X=HF (5) or BF3 (6), respectively.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Peer Reviewe
Natural Audio Data Augmentation Techniques
Get PDFPython code supporting this thesis is available at: https://github.com/vaniastankov/Master-Thesis-codeKünstliche Vergrößerung von Datensätzen, ein Prozess, der auch als Data Augmentation bekannt ist und dazu dient, ein maschinelles Lernmodell zu trainieren und zu bewerten, wird seit langem angewendet und erforscht. Diese Arbeit befasst sich mit einem Problem der Data Augmentation im Bereich der Audioverarbeitung. Die Anwendung von Techniken zur Data Augmentation auf Tonaufnahmen ist ein Forschungsbereich, der bisher weitgehend unerforscht ist. Viele frühere Arbeiten stützen ihre Ansätze auf Erkenntnisse aus anderen Bereichen, wie zum Beispiel der Bildverarbeitung (Computer Vision). Andere wenden oft allgemeine Transformationen an, die in der Signalverarbeitung bekannt sind. Insbesondere fehlt es in der bisherigen Forschung an einem Verständnis für natürliche oder Umwelttransformationen, die während des Aufnahmevorgangs an einem Tonsignal auftreten. Dieses Thema wird in dieser Arbeit behandelt. Bei der Lösung eines typischen Problems der Audio-Klassifikation, bei dem Klänge entsprechend ihrer Quellen gekennzeichnet werden, werden mehrere neue Techniken zur Data Augmentation für Audio vorgeschlagen und mit bestehenden Praktiken verglichen. Als Ergebnis werden zuverlässige Metriken erzielt, die mit vorherigen Arbeiten vergleichbar sind. Die vorgeschlagenen Techniken stehen öffentlich zur Verfügung. Darüber hinaus werden Vorschläge für weitere Forschungsbereiche gemacht.Artificial enlargement of datasets, a process also known as data augmentation, used to train and evaluate a machine learning model, has been applied and researched for a long time. This work addresses a problem of data augmentation in the audio domain. The application of data augmentation techniques to audio recordings is a field primarily uncovered by research. Many previous works base their approaches on knowledge from other domains, such as computer vision. Others often apply general transformations known in signal processing.
In particular, existing research lacks an understanding of natural, or environmental, transformations happening to an audio signal during the recording process. This topic is addressed in this work. While solving a typical audio classification problem, which is labeling sounds respective to their sources, several new audio data augmentation techniques are proposed and compared to existing practices. A set of reliable metrics comparable with preceding works is achieved as a result. Proposed techniques are openly available. Additionally, suggestions for further research are provided