Search methods for an autonomous underwater vehicle using scalar measurements

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution July 1996The continuing development of the autonomous underwater vehicle as an oceanographic research tool has opened up the realm of scientific possibility in the field of deep ocean research. The ability of a vehicle to travel to the ocean floor untethered, collect data for an extended period of time and return to the surface for recovery can make precise oceanographic surveying more economically practical and more efficient. This thesis investigates several scalar parameter searching techniques which have their basis in mathematical optimization algorithms and their applicability for use specifically within the context of autonomous underwater vehicle dynamics. In particular, a modified version of the circular gradient evaluation in the simulated environment of a hydrothermal plume is examined as a test case. Using a priori knowledge of the expected structure of the scalar parameter contour is shown to be advantageous in optimizing the search

New Record of \u3ci\u3eBrachycercus Maculatus\u3c/i\u3e Berner (Ephemeroptera: Caenidae) From New York and a Key to Larvae of Northeastern Species

Brachycercus maculatus, a member of a rare group of mayflies, is now recorded for the first time from New York State in the upper Hudson River. An illustrated key to the Brachycercus larvae of northeastern North America is provided to spur further study of the genus in the region

Principles Driven Leadership: Thoughts, Observations And Conceptual Model

Leadership has as many definitions as it does books written on the subject. Discussions regarding the subject often migrate toward the differences between leadership and management. The purpose of this paper is to provide a conceptual view of leadership based on experience, observation and lessons learned. A conceptual model and a comprehensive set of principles are presented that can be used as a blueprint toward developing a sound foundation of leadership

Stoichiometric regulation in micro- and mesozooplankton

Aquatic ecosystems experience large natural variation in elemental composition of carbon (C), nitrogen (N) and phosphorus (P), which is further enhanced by human activities. Primary producers typically reflect the nutrient ratios of their resource, whose stoichiometric composition can vary widely in conformity to environmental conditions. In contrast, C to nutrient ratios in consumers are largely constrained within a narrow range, termed homeostasis. In comparison to crustacean zooplankton, less is known about the ability of protozoan grazers and rotifer species to maintain stoichiometric balance. In this study, we used laboratory experiments with a primary producer (Nannochloropsis sp.), three different species of protozoan grazers and one mesozooplankton species: two heterotrophic dinoflagellates (Gyrodinium dominans and Oxyrrhis marina), a ciliate (Euplotes sp.) and a rotifer (Brachionus plicatilis) to test the stoichiometric response to five nutrient treatments. We showed that the dependency of zooplankton C:N:P ratios on C: nutrient ratios of their food source varies among species. Similar to the photoautotroph, the two heterotrophic dinoflagellates weakly regulated their internal stoichiometry. In contrast, the strength of stoichiometric regulation increased to strict homeostasis in both the ciliate and the rotifer, similar to crustacean zooplankton. Our study further shows that ciliate and rotifer growth can be constrained by imbalanced resource supply. It also indicates that these key primary consumers have the potential to trophically upgrade poor stoichiometric autotrophic food quality for higher trophic levels

Leadership Systems Model: An Integration Of People, Process, And Behaviors In A Dynamic And Evolving Environment

Defining, observing, and measuring leadership skills, styles and approaches are far from being a new effort. Although research has provided much information regarding leadership, the classical leadership theories and models, processes, and behavioral views must be further integrated in order to provide a richer and wider view of leadership. Furthermore, organizations are not static; they are constantly changing and evolving over time. The purpose of this paper is to provide a conceptual model integrating these views using a systems level theory to understand the aggregate nature of leadership

Application of third generation synchrotron source to studies of noncrystalline materials : In-Se amorphous films

The local structure of vacuum evaporated In-Se amorphous films, containing 50, 60, and 66 at .% Se, was studied using differential anomalous X -ray scattering and extended X -ray absorption fine structure. Both intensity and absorption spectra were measured in the vicinity of the absorption K -edge of Se. The differential anomalous X -ray scattering data were converted to real space by the inverse Fourier transform yielding the differential radial distribution functions. The obtained results provide evidence for the presence of Se-In spatial correlations for In5 0 Se50 and Se-In and Se-Se correlations for In40 Se60 and In34 Se66 within the first coordination sphere

Ab initio study of electronic and magnetic structure and structural phase transition of (Fe 1-xMn x) 2P 1-yGe y alloys

The paper presents results of the ab initio electronic structure calculations performed for the (Fe0:5Mn0:5)2P0:67Ge0:33 alloy, a member of (Fe1xMnx)2P1yGey family of alloys showing a giant magnetocaloric e ffect. Calculations con rmed the strong relationship between the magnetic state and crystal structure of the alloy. To investigate the isostructural phase transition driven by external magnetic eld observed in (Fe0:9Mn1:1)P0:8Ge0:2 we utilized the xed spin moment approach. Total energy analysis con rmed the occurrence of isostructural phase transition

Exploring modularity in biological networks

Network theoretical approaches have shaped our understanding of many different kinds of biological modularity. This essay makes the case that to capture these contributions, it is useful to think about the role of network models in exploratory research. The overall point is that it is possible to provide a systematic analysis of the exploratory functions of network models in bioscientific research. Using two examples from molecular and developmental biology, I argue that often the same modelling approach can perform one or more exploratory functions, such as introducing new directions of research, offering a complementary set of concepts, methods and algorithms for individuating important features of natural phenomena, generating proofs of principle demonstrations and potential explanations for phenomena of interest and enlarging the scope of certain research agendas. This article is part of the theme issue 'Unifying the essential concepts of biological networks: biological insights and philosophical foundations'

2016 International Orthoptic Congress Burian Lecture: folklore or evidence?

The theme of the 2016 Burian Lecture is how our understanding of strabismus has been changed by the research carried out in our laboratory in Reading over the years. Accommodation and convergence are fundamental to Orthoptics, but actual responses have often been very different to what we had expected. This paper outlines how our laboratory’s understanding of common issues such as normal development of accommodation and convergence, their linkage, intermittent strabismus, anisometropia, orthoptic exercises and risk factors for strabismus have changed. A new model of thinking about convergence and accommodation may help us to better understand and predict responses in our patients