More than one way to see it: Individual heuristics in avian visual computation

Comparative pattern learning experiments investigate how different species find regularities in sensory input, providing insights into cognitive processing in humans and other animals. Past research has focused either on one species’ ability to process pattern classes or different species’ performance in recognizing the same pattern, with little attention to individual and species-specific heuristics and decision strategies. We trained and tested two bird species, pigeons (Columba livia) and kea (Nestor notabilis, a parrot species), on visual patterns using touch-screen technology. Patterns were composed of several abstract elements and had varying degrees of structural complexity. We developed a model selection paradigm, based on regular expressions, that allowed us to reconstruct the specific decision strategies and cognitive heuristics adopted by a given individual in our task. Individual birds showed considerable differences in the number, type and heterogeneity of heuristic strategies adopted. Birds’ choices also exhibited consistent species-level differences. Kea adopted effective heuristic strategies, based on matching learned bigrams to stimulus edges. Individual pigeons, in contrast, adopted an idiosyncratic mix of strategies that included local transition probabilities and global string similarity. Although performance was above chance and quite high for kea, no individual of either species provided clear evidence of learning exactly the rule used to generate the training stimuli. Our results show that similar behavioral outcomes can be achieved using dramatically different strategies and highlight the dangers of combining multiple individuals in a group analysis. These findings, and our general approach, have implications for the design of future pattern learning experiments, and the interpretation of comparative cognition research more generally

Microwave spectroscopy of a carbon nanotube charge qubit

Carbon nanotube quantum dots allow accurate control of electron charge, spin and valley degrees of freedom in a material which is atomically perfect and can be grown isotopically pure. These properties underlie the unique potential of carbon nanotubes for quantum information processing, but developing nanotube charge, spin, or spin-valley qubits requires efficient readout techniques as well as understanding and extending quantum coherence in these devices. Here, we report on microwave spectroscopy of a carbon nanotube charge qubit in which quantum information is encoded in the spatial position of an electron. We combine radio-frequency reflectometry measurements of the quantum capacitance of the device with microwave manipulation to drive transitions between the qubit states. This approach simplifies charge-state readout and allows us to operate the device at an optimal point where the qubit is first-order insensitive to charge noise. From these measurements, we are able to quantify the degree of charge noise experienced by the qubit and obtain an inhomogeneous charge coherence of 5 ns. We use a chopped microwave signal whose duty-cycle period is varied to measure the decay of the qubit states, yielding a charge relaxation time of 48 ns

An evaluation of the post-ignition unblocking behavior of solid propellant aft-end ignition systems Final report

Determining postignition interactions between igniter and main motor flow by aft-end heated air simulation of solid propellant exhaus

If the Shoe Fits: Rethinking Minimum Contacts and the FSIA Commercial Activity Exception

The question explored in this Note is whether, under the direct effect clause of the Foreign Sovereign Immunities Act commercial activities exception, a foreign sovereign must have minimum contacts with the United States in order for a U.S. court to assert personal jurisdiction over the entity. Examining personal jurisdiction over foreign states under the direct effect clause requires exploring the interaction between constitutional law and principles of international law. The minimum contacts analysis highlights the tension between applying constitutional due process protection to a foreign state, while simultaneously asserting jurisdiction over its commercial activities. Denying jurisdiction over a foreign sovereign under the Due Process Clause may defeat the intent of the FSIA’s immunity exceptions created to provide relief for U.S. plaintiffs injured by foreign states. Deciding questions of personal jurisdiction over foreign entities requires identifying the goals of foreign sovereign immunity, why the FSIA established exceptions to that immunity, and what constitutional protections the United States should provide to foreign states

Throwing the Switch: Eisenhower, Stevenson and the African-American Vote in the 1956 Election

This paper seeks to contextualize the 1956 election by providing a summary of the African American political alignment during the preceding half-century. Winning a greater portion of the black vote was a central tenant of the 1956 Eisenhower Campaign strategy. In the 1956 election a substantial shift occurred among the historically democratic black electorate. The vote shifted because of disillusionment with the Democrats and Eisenhower’s civil rights record. The swing however, was less pronounced for Republican congressional candidates. This paper draws upon extensive primary material, including countless newspapers, magazines, the NAACP Papers, and published primary sources to form the core of its argument. Comprehensive secondary research ground this paper in the inadequate literature on the topic

Secrecy Rate Analysis of UAV-Enabled mmWave Networks Using Matérn Hardcore Point Processes

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Communications aided by low-altitude unmanned aerial vehicles (UAVs) have emerged as an effective solution to provide large coverage and dynamic capacity for both military and civilian applications, especially in unexpected scenarios. However, because of their broad coverage, UAV communications are prone to passive eavesdropping attacks. This paper analyzes the secrecy performance of UAVs networks at the millimeter wave band and takes into account unique features of air-to-ground channels and practical constraints of UAV deployment. To be specific, it explores the 3-D antenna gain in the air-to-ground links and uses the Matérn hardcore point process to guarantee the safety distance between the randomly deployed UAV base stations. In addition, we propose the transmit jamming strategy to improve the secrecy performance in which part of UAVs send jamming signals to confound the eavesdropper

An Unsettling Civil War: A Review of Ruin Nation

This review of Meghan Kate Nelson\u27s Ruin Nation examines the immense environmental destruction and social impact of the Civil War. This brief review analyzes Nelson\u27s work and it\u27s implications for Civil War history

Do red deer hinds prefer stags that produce harsh roars in mate choice contexts?

Red deer stags give two types of roars during the breeding season, termed ‘common’ and ‘harsh’ roars. This study tested the hypothesis that the characteristic spectro-temporal structure of male harsh roars functions to directly attract females towards male callers during the breeding season. The results show that oestrous hinds look for longer towards speakers broadcasting sequences containing harsh roars, but do not preferentially approach or spend more time in close proximity to speakers broadcasting harsh roars over those broadcasting only common roars. While these observations confirm that the specific acoustic structure of male harsh roars functions to draw the attention of hinds, they are not consistent with the notion that these calls have an immediate impact on mate choice decisions by stimulating oestrous hinds to move towards male callers. Consequently, we suggest that intersexual selection through female mate choice is unlikely to be a major factor driving the evolution of male red deer harsh roars