The action of the mapping class group on the space of geodesic rays of a punctured hyperbolic surface

Let Σ be a complete finite-area orientable hyperbolic surface with one cusp, and let R be the space of complete geodesic rays in Σ emanating from the puncture. Then there is a natural action of the mapping class group of Σ on R. We show that this action is "almost everywhere" wandering

The Effect of Fe-enrich Phase on the Pitting Corrosion Resistance of Al Alloy in Various Neutral Sodium Chloride Solutions

The pitting corrosion of 5052 alloy was investigated as function of chloride concentrations by using an electrochemical method, scanning electron microscope and energy dispersive X-Ray spectroscopy in neutral sodium chloride solutions at 293 K. The pitting corrosion of pure Al was also investigated under the same experimental condition for the comparison. The pitting potential obtained for 5052 alloy and pure Al decreased with increasing chloride concentration. The pitting potential of pure Al is higher than that of 5052 alloy where pitting resistance of pure Al is better than that 5052 alloy. The linear equation implies that certain pitting potential becomes a relevant parameter for predicting certain chloride ion concentration. The synergic role of chloride ion and a localized galvanic corrosion between aluminium metal and iron-containing constituent contribute the process of pitting for 5052 alloy

Remarks on the energy of regular graphs

The energy of a graph is the sum of the absolute values of the eigenvalues of its adjacency matrix. This note is about the energy of regular graphs. It is shown that graphs that are close to regular can be made regular with a negligible change of the energy. Also a $k$-regular graph can be extended to a $k$-regular graph of a slightly larger order with almost the same energy. As an application, it is shown that for every sufficiently large $n,$ there exists a regular graph $G$ of order $n$ whose energy $\left\Vert G\right\Vert_{\ast}$ satisfies $$\left\Vert G\right\Vert_{\ast}>\frac{1}{2}n^{3/2}-n^{13/10}.$$ Several infinite families of graphs with maximal or submaximal energy are given, and the energy of almost all regular graphs is determined.Comment: 12 pages. V2 corrects a typo. V3 corrects Theorem 1

2015 State of the Bay Report

The Casco Bay Estuary Partnership helps track and report on changing conditions within the Bay and its watershed. Every five years, in its State of the Bay report, the Partnership portrays how Casco Bay is faring—what trends are evident, what progress is visible, and what new challenges are emerging. By tracking indicators at regular intervals over decades, the Partnership helps identify the collective work needed to sustain the region. State of the Bay 2015, summarized here and detailed online at www.cascobayestuary.org/state-of-the-bay-2015, reveals a complex array of factors shaping the ecology and economy of the Casco Bay region. There’s a mix of encouraging news, interspersed with unsettling trends. The warming climate represents a vast and unpredictable driver of regional change—with hotter ocean and air temperatures, more frequent and extreme precipitation, and rising seas (already evident in flooding at extreme high tides). Indicators used in the past (and included in the 2015 report) do not fully account for the dynamic interplay of forces currently at work on Casco Bay. Future reports will include new indicators to help gauge the pace and impacts of far reaching change.https://digitalcommons.usm.maine.edu/cbep-state-of-the-bay/1000/thumbnail.jp

Quantitative rigidity results for conformal immersions

In this paper we prove several quantitative rigidity results for conformal immersions of surfaces in $\mathbb{R}^n$ with bounded total curvature. We show that (branched) conformal immersions which are close in energy to either a round sphere, a conformal Clifford torus, an inverted catenoid, an inverted Enneper's minimal surface or an inverted Chen's minimal graph must be close to these surfaces in the $W^{2,2}$-norm. Moreover, we apply these results to prove a corresponding rigidity result for complete, connected and non-compact surfaces.Comment: 27 pages, to appear in Amer. J. Mat

Investigating the role of vitamin K in Axl-mediated melanoma progression and chemotherapeutic resistance

Postponed access: the file will be accessible after 2020-06-01Metastatic melanoma is a highly aggressive cancer with a very poor prognosis and current therapies remain inadequate. Norway is among the top five countries with the highest incidence of melanoma. Malignant cells carry oncogenic mutations that engender uncontrolled growth and elicit activation of epithelial-to-mesenchymal transition (EMT), an embryonic gene program that induces cancer stem cell features, invasiveness, survival, chemotherapeutic resistance, immune modulation and metastasis. The receptor tyrosine kinase, Axl, is upregulated with this EMT program and overexpressed in several human cancers. Axl is upregulated in a subset of more invasive tumors and thought to be an important facilitator of resistance to therapeutics targeted against oncogenic RTKs. Activation of Axl is dependent on the binding of its ligand Gas6. Gas6 is a vitamin K dependent protein that is modified by the γ-carboxylation of glutamic acid residues in the N-terminal Gla domain. Vitamin K serves as the cofactor for the enzyme γglutamyl carboxylase (GGCX) that catalyzes the γ-carboxylation of the glutamic acid residues. BGB324 is an Axl kinase inhibitor currently in ongoing clinical trial against different types of cancers. Here we first characterized the expression of Axl, Gas6 and vitamin K enzymes such as GGCX in 20 melanoma cell lines and determine their correlation with clinical outcome. Our results suggest that GGCX but not Axl and Gas6 expression correlates with poor patient prognosis. We further evaluated the effect of vitamin K and BGB324 on 5 selected cell lines. We found that the vitamin K increases the expression of Axl and other TAM receptors, GGCX and EMTrelated genes while when treated with BGB324 expression reduced or remained unchanged. However, BGB324 was not able to elicit this effect if the cells were cultured in vitamin K suggesting acquisition of a resistant phenotype. We also evaluated the effect of vitamin K on NZM cell proliferation, migration and spheroid formation. Finally, we show that vitamin K upregulated several plasticity markers in presence of vitamin K using mass cytometry (CyTOF).Master's Thesis in Biomedical SciencesMAMD-MEDBIBMED39

Influence of the impaction angle on the triboelectric charging of aerosol nanoparticles

A low pressure impactor is used to measure triboelectric charging behavior of metallic nanoparticles. Ag nanoparticles, produced by spark discharge, were impacted onto Pt sputtered targets. The influence of the impaction angle and impaction velocity on the triboelectric charging was investigated. While for perpendicular impaction the charge transfer behavior of previous work was confirmed, the oblique impaction revealed new phenomena. Additional charge transfer was observable, which increases with obliqueness. The possibility of mass transfer between particle and target due to the high-energy collisions was also investigated. SEM characterization and Auger spectroscopy indicate mass transfer from the particle to the target surface