Flight to Quality for Large Financial Institutions

Local correlation analysis is used to investigate flight to quality among large financial institutions before, during, and after the financial crisis of 2008-2009. While standard correlation captures general overall linear association, local correlation analysis more accurately captures changes in the associations in response to changing market conditions. Using raw, market-adjusted, and industry-adjusted stock returns of individual banks, we investigate the performance of troubled banks and the change in investing behavior. Investors react to noisy information from the financial difficulties encountered by banking institutions. This reaction results in flight to quality. While the traditional Pearson correlations capture general overall linear association, local correlation analysis captures changes in the association in response to changing market conditions. Thus, local correlation analysis more accurately measures changes in correlation where it matters most: in the loss tail of the distribution of financial returns; leading to more appropriate diversification, portfolio management, and within-industry implications

The Takagi problem on the disk and bidisk

We give a new proof on the disk that a Pick problem can be solved by a rational function that is unimodular on the unit circle and for which the number of poles inside the disk is no more than the number of non-positive eigenvalues of the Pick matrix. We use this method to find rational solutions to Pick problems on the bidisk

A study of time concepts found in primary reading materials

Thesis (Ed.M.)--Boston Universit

Searching for the Soldier Pheromone: Behavioral Effects of Soldiers and Soldier-Produced Chemicals in the Formosan Subterranean Termite, Coptotermes formosanus (Blattodea: Rhinotermitidae))

The Formosan subterranean termite, Coptotermes formosanus, is a eusocial insect and an invasive urban pest. Colonies function through a division of labor among castes (i.e., queens and kings, workers, and soldiers). Though soldiers are energetically expensive to maintain, C. formosanus has a relatively large soldier caste (~10% of the colony). Soldiers are physically unable to collect food or build tunnels but are regularly found with foraging workers. In some species, soldiers influence the worker foraging behavior. In C. formosanus, aside from defense, the roles soldiers play remains unknown. In this study, we determined if soldiers influence the exploratory foraging of workers in C. formosanus. Groups of workers were introduced to planar foraging arenas to forage with different soldier concentrations. There was no significant difference in tunnel length, tunnel complexity, or food consumption within four days between foraging groups with 100 workers and 0, 2, 10, or 30 soldiers. Based on this study, no relationship was found between worker exploratory foraging activity and soldier presence. C. formosanus soldiers, like some other termite species, produce a defensive secretion for chemical defense. C. formosanus defensive secretion composition was previously investigated, showing lignoceric acid and hexacosanoic acid as two major components, but no behavioral influence was investigated. Choice assays showed C. formosanus workers were repelled by lignoceric acid, hexacosanoic acid, a mixture of lignoceric and hexacosanoic acids, and the crude extract of the soldier defensive secretion. Workers consumed less paper treated with the mix of lignoceric and hexacosanoic acid, indicating that the soldier defensive secretion may elicit repellant behavior in workers, allowing workers to escape from a potential threat. We additionally analyzed cuticular hydrocarbons (CHCs) from workers and soldiers to examine differences that may identify a soldier- or worker-specific compound. No qualitative difference was detected in CHC profiles between workers and soldiers, but of the 15 peaks identified, 13 differed significantly in relative abundance. These differences may enable colony members to distinguish between workers and soldiers, but further behavioral tests are required. By investigating the multifunctional roles of soldiers in termite colonies, this study helps better understand the complex nature of communication in social insects

Anomalous scattering of light on Triton

Researchers report here the discovery of an isolated region of anomalously forward scattering materials on the surface of Triton. The researchers' best-fit Hapke parameters indicate that regolith particles in the anomalous scattering region are not only less backward scattering, but also slightly lower in single scattering albedo than average materials on Triton's surface. While it might be possible to account for such differences in terms of differences in particle size and transparency, it is also possible that the anomalous region is compositionally distinct from other terrains. It is noteworthy that, for the anomalous region, there exists a distinctively strong spatial correlation between the photometric ratios at different phase angles, and that, relative to other terrains, the anomalous region reddens at a different rate with increasing phase angle

05/10/1940 Letter from Joseph Edward McCarthy to Oliver V. Pelletier

Letter from Joseph Edward McCarthy, 6th Bishop of Portland, Maine, to Oliver V. Pelletier.https://digitalcommons.usm.maine.edu/fac-lpg-letters-1940-1946/1012/thumbnail.jp

Nitrogen availability and transformations in Missisquoi Bay, Lake Champlain : effects on phytoplankton community structure and cyanobacterial blooms

L'objectif de l'étude était de déterminer la disponibilité de l'azote (N) et les transformations dans la colonne d'eau (WC) et l'interface eau-sédiments (SWI), et d'établir des liens avec les éclosions de cyanobactéries dans la baie Missisquoi du lac Champlain. Ces paramètres ont été évalués à l'embouchure de la rivière aux Brochets et dans le bassin central, afin d'obtenir un gradient environnemental pour étudier l'effet des décharges de nutriments sur le cycle de l'azote et la structure des communautés de phytoplancton (PCS). Les résultats portent à croire qu'en général, les nutriments ne limitent pas la productivité primaire, mais que l'azote peut la limiter à petite échelle. Contrairement à nos hypothèses, le phytoplancton semblait gérer les concentrations en nutriments, et non l'inverse. La PCS n'affectait pas la consommation en NH4+ dans la WC. De même, le taux de régénération du NH4+ dans la WC n'était pas relié à la PCS, ce qui réfute l'hypothèse que les cyanobactéries inhibent la régénération. Les sédiments agissaient comme un puits de NO3-, tel que prédit, mais étaient aussi une source de NH4+ vers la WC, contrairement aux hypothèses. Une biomasse élevée de cyanobactéries était associée avec une relâche subséquente de NO3- des sédiments, ce qui pourrait impliquer une stimulation de la nitrification. L'anammox explique de 6 à 10% de la production totale de diazote, mais la dénitrification en était le principal vecteur. Les taux de dénitrification étaient reliés à la concentration instantanée en azote de la WC, mais pas à ses fluctuations. On observe des relations similaires entre les flux de NO3- dans les sédiments et la dénitrification avec la biomasse cyanobactérienne antérieure. Cela suggère que des concentrations inférieures en azote dans la WC, à la suite de floraisons de cyanobactéries, ont rendu possibles des taux de dénitrifications inférieurs. Les données ne corroborent pas l'hypothèse selon laquelle la dénitrification mènerait à des conditions propices pour les cyanobactéries fixatrices d'azote. Au contraire, les résultats suggèrent que les conditions propices aux cyanobactéries fixatrices d'azote causent une réduction des taux de dénitrification. Le lac était un puits net d'azote dans un budget préliminaire calculé en utilisant le cycle du NH4+ dans la WC et les flux d'azote à l'SWI, comparés aux apports en azote estimés des affluents. Ces calculs révèlent une source d'azote « manquante », qui pourrait être la fixation d'azote dans la WC selon les résultats. Les taux observés de fixation d'azote dans la WC n'étaient pas différents de ceux des contrôles expérimentaux, mais même ces taux négligeables sont d'un ordre de grandeur plus élevé que ceux nécessaires pour combler l'azote « manquant ».\ud ______________________________________________________________________________ \ud MOTS-CLÉS DE L’AUTEUR : cycle de l'azote, cyanobactéries, dénitrification, eutrophisation, budget d'azot