Tautological classes of strata of exact differentials

Strata of exact differentials are moduli spaces for differentials on Riemann surfaces with vanishing absolute periods. Our main result is that classes of closures of strata of exact differentials inside the moduli space of multi-scale differentials lie in the divisorial tautological ring. By relating exact differentials to rational functions we obtain a new proof that classes of Hurwitz spaces are tautological and a new method for computations

Equations of linear subvarieties of strata of differentials

For a linear subvariety $M$ of a stratum of meromorphic differentials, we investigate its closure in the multi-scale compactification constructed by Bainbridge-Chen-Gendron-Grushevsky-M\"oller. We prove various restrictions on the type of defining linear equations in period coordinates for $M$ near its boundary, and prove that the closure is locally a toric variety. As applications, we give a fundamentally new proof of a generalization of the cylinder deformation theorem of Wright to the case of meromorphic strata, and construct a smooth compactification of the Hurwitz space of covers of the Riemann sphere.Comment: v2: updated version with minor edits, accepted to Geometry&Topolog

A Zero Lyapunov Exponent in Genus 33 Implies the Eierlegende Wollmilchsau

We prove that the closed orbit of the Eierlegende Wollmilchsau is the only $\text{SL}(2,\mathbb{R})$-orbit closure in genus three with a zero Lyapunov exponent in its Kontsevich-Zorich spectrum. The result recovers previous partial results in this direction by Bainbridge-Habegger-M\"oller and the first named author. The main new contribution is an understanding of the Forni subspace along a degeneration toward the boundary of the moduli space of curves. This results in a simple geometric criterion that excludes the existence of a Forni subspace. Another key ingredient is the solution to the jump problem from the work of Hu and the third named author.Comment: 33 pages, 8 figures, revised following referee repor

Pediatric calcaneal fractures

Although operative treatment of displaced, intra-articular fractures of the calcaneus in adults is generally accepted as standard practice, operative treatment for the same fractures in the skeletally immature remains controversial, potentially because the outcome for fracture types (intra- vs. extra-articular) and severity (displaced vs. nondisplaced) have been confounded in studies of children. We review herein the results of 21 displaced, intra-articular fractures in 18 skeletally immature patients, who were treated with open reduction and internal fixation using a standard surgical approach and protocol developed for adults. The average pre-operative Böhler's angle on the injured side was −5° (range: −35 – +35) compared to 31° (range: +22 – +47) on the uninjured side, indicating substantial displacement. There were no post-operative infections or wound healing problems, and all but one patient was followed to union (average follow-up: 1.5 years; range: 0.30–4.3 years). Maintenance of reduction was confirmed on follow-up radiographs with an average Böhler's angle of 31° (range: +22 – +49). We demonstrate that results for operative fixation of displaced, intra-articular calcaneal fractures in the skeletally immature are comparable to those in adults when the treatment protocol is the same

The influence of electricity on socio-economic development

Die Intention dieser Forschungsarbeit war es, herauszufinden inwieweit eine direkte kausale Verbindung zwischen dem Gebrauch einer bestimmten Energieart, in diesem Fall Elektrizität, Wirtschaftswachstum und erwarteten Auswirkungen auf die Lebensumstände Einzelner bewiesen werden kann. An das Thema wurde von drei verschiedenen Perspektiven herangegangen. Zum Ersten wurde die technologische Seite beleuchtet indem an die Eigenschaften von Elektrizität und ihre wirtschaftlich relevantesten Anwendungsbereiche herangeführt wurde. Zweitens wurden die Auswirkungen der Einführung einer neuartigen Energiequelle auf die Wirtschaft während des Industrialisierungsprozesses beschrieben. Drittens wurden die Effekte auf die Gesellschaft – im Speziellen auf die politischen und kulturellen Bereiche – eingehender betrachtet. Diese Untersuchung wurde aus einer globalgeschichtlichen Perspektive anhand von Gegenüberstellungen verschiedener Argumentationen namhafter Wissenschafter aus den Bereichen Wirtschafts- und Sozialgeschichte durchgeführt, welche entweder zugunsten oder zuungunsten von Behauptungen über ein klares, vermutetes Verhältnis zwischen Energie und sozioökonomischem Wandel verliefen. Des Weiteren beschäftigt sich diese Forschungsarbeit vordergründig mit Westeuropa und Nordamerika im 19. und frühen 20. Jahrhundert. Die Ergebnisse zeigen, dass die Wahrscheinlichkeit eines Kausalzusammenhangs zwischen der Anwendung von Elektrizität in einem Wirtschaftssystem und positiven Auswirkungen auf das Wirtschaftswachstum und auf die Verbesserung von Lebensstandards innerhalb einer Gesellschaft sehr groß ist. Nichtsdestotrotz gibt es wenige effektive Beweise und die Durchführung von weiterer primärer Forschung auf diesem Gebiet um die Behauptungen über das Vorhandensein einer Kausalkette der drei untersuchten Bereiche faktisch zu belegen ist wünschenswert.The intention of this research was to investigate to which extent there is proof for a direct causal relationship between the use of a specific kind of energy, in this case electricity, economic development and as a presumed result a change in living conditions. The issue was tackled from three different perspectives: first, the technological side by explaining the characteristics of electricity and its economically most relevant applications. Second, the effects the implementation of a novel energy source had on the economy in the industrialisation process. Third, the effects on society – in particular the political and cultural sphere – were looked at in more detail. This investigation was carried out from a global history perspective by juxtaposing arguments by renowned scholars in the fields of economic history and social history in support or opposing statements about the distinct presupposed relationship between energy and socio-economic change. Furthermore, the research is particularly concerned with Western Europe and North America in the 19th and early 20th century. The results reveal that the likelihood of a causal relationship between the implementation of electricity in an economic system and positive effects on growth and the betterment of living conditions for the society affected is very high. However, factual proof is still scarce and more primary research is desirable in order to fully substantiate the claim of the presence of a causal chain of the three realms investigated

Modeling the variability of shapes of a human placenta

While it is well-understood what a normal human placenta should look like, a deviation from the norm can take many possible shapes. In this paper we propose a mechanism for this variability based on the change in the structure of the vascular tree

High-speed, long-term, 4D in vivo lifetime imaging in intact and injured zebrafish and mouse brains by instant FLIM

Traditional fluorescence microscopy is blind to molecular microenvironment information that is present in the emission decay lifetime. With fluorescence lifetime imaging microscopy (FLIM), physiological parameters such as pH, refractive index, ion concentration, dissolved gas concentration, and fluorescence resonance energy transfer (FRET) can be measured. Despite these benefits, existing FLIM techniques are typically slow, noisy, and hard to implement due to expensive instrumentation and complex post-processing. To overcome these limitations, we present instant FLIM, a method that allows real-time acquisition and display of two-photon intensity, lifetime, and phasor imaging data. Using analog signal processing, we demonstrate in vivo four-dimensional (4D) FLIM movies by imaging mouse and zebrafish glial cell response to injury over 12 hours through intact skulls. Instant FLIM can be implemented as an upgrade to an existing multiphoton microscope using cost-effective off-the-shelf components, requires no data post-processing, and is demonstrated to be compatible with FD-FLIM super-resolution techniques

A novel preclinical model for rheumatoid arthritis research

Based on increasing knowledge on the pathogenesis of rheumatoid arthritis (RA), more and more potential therapeutics have been developed. To evaluate their therapeutic efficacy, safety and toxicity, appropriate animal models are required. Although rodent models of RA have been extensively used for preclinical evaluation, the differences between rodents and humans limit their usability for some species-specific therapeutics. Therefore, autoimmune arthritis developed in a non-human primate with essential hallmarks of RA will be an alternative model for preclinical studies