University of Maine

About: University of Maine is a education organization based out in Orono, Maine, United States. It is known for research contribution in the topics: Population & Ice sheet. The organization has 8637 authors who have published 16932 publications receiving 590124 citations. The organization is also known as: University of Maine at Orono.

Glacier advance in southern middle-latitudes during the Antarctic Cold Reversal

Abstract: The geographic extent of cooling associated with the Antarctic Cold Reversal is unclear. Dating of glacial moraines in New Zealand suggests that the cooling extended into the southern mid-latitudes, possibly as a result of the northward migration of the southern subtropical front.

Principles and applications of BPCS steganography

Abstract: Steganography is a technique to hide secret information in some other data (we call it a vessel) without leaving any apparent evidence of data alteration. All of the traditional steganographic techniques have limited information-hiding capacity. They can hide only 10% (or less) of the data amounts of the vessel. This is because the principle of those techniques was either to replace a special part of the frequency components of the vessel image, or to replace all the least significant bits of a multivalued image with the secret information. Our new steganography uses an image as the vessel data, and we embed secret information in the bit-planes of the vessel. This technique makes use of the characteristics of the human vision system whereby a human cannot perceive any shape information in a very complicated binary pattern. We can replace all of the noise-like regions in the bit-planes of the vessel image with secret data without deteriorating the image quality. We termed our steganography BPCS-Steganography, which stands for Bit-Plane Complexity Segmentation Steganography. We made an experimental system to investigate this technique in depth. The merits of BPCS-Steganography found by the experiments are as follows. 1. The information hiding capacity of a true color image is around 50%. 2. A sharpening operation on the dummy image increases the embedding capacity quite a bit. 3. Canonical Gray coded bit planes are more suitable for BPCS-Steganography than the standard binary bit planes. 4. Randomization of the secret data by a compression operation makes the embedded data more intangible. 5. Customization of a BPCS-Steganography program for each user is easy. It further protects against eavesdropping on the embedded information.

Three Magic Letters: Getting to Ph.D

Abstract: Three Magic Letters: Getting to Ph.D. by Michael T. Nettles and Catherine M. Millett. Baltimore, MD: The Johns Hopkins University Press, 2006. In the spring of 1995, Catherine Millett, a doctoral student at the time, approached faculty member Michael Nettles and asked: "How do doctoral students find the financial resources to support their academic interests and see themselves through the timely completion of their PhD degrees?" So began the exchange that spawned the collaboration that led to one of the most comprehensive and ambitious projects on doctoral education in the United States, Three Magic Letters: Getting to the Ph.D. This informative, comprehensive, and enjoyable book goes far beyond the initial question about funding to examine essentially all aspects of the doctoral experience. Nettles and Millett have collected, compiled, analyzed, and interpreted an impressive array of data to shed light on the complexity of the doctoral experience. A long-awaited release, Three Magic Letters offers readers an abundance of information regarding determinants of progress to the PhD, as their work reflects the findings of the largest survey of doctoral students yet completed. A total of 9,036 doctoral students in 11 fields of study across 21 universities were surveyed regarding their educational experience and progress to the degree. The study is broad and comprehensive, making it an invaluable resource for researchers, policy makers, faculty members, and doctoral students themselves. Nettles and Millet's work represents the burgeoning emphasis of studying doctoral education from the disciplinary perspective, as has been suggested by experts such as Golde and Dore (2004). This approach broadens our understanding of the contexts and cultures that influence the doctoral experience. The book begins with a refresher on the history of the doctoral degree as well as an overview of existing research on the PhD experience, especially in terms of time to degree, attrition, and completion, and it continues with a synopsis of the research design and sample. Subsequent chapters focus on findings related to particular aspects of the doctoral experience and their influence upon degree completion. Topics covered include admissions and screening, funding, socialization, research productivity, satisfaction, time to degree, performance, field differences, and group differences. The book is an unprecedented integration of topics that have previously been examined but never in a way that acknowledges disciplinary perspectives and demographic variables as Nettles and Millett do. The study findings are presented in way that is accessible and interesting. The conceptual analytical framework that guides Nettles and Millett in their research and writing builds upon the framework originally developed by Berelson (1960), in his seminal study on doctoral education in the United States, as well as upon the work by Bowen and Rudenstine (1992), among others. This framework is based upon the five experiences on which Nettles and Millett focused in their study, including type of funding, socialization, research productivity, satisfaction and stopping out of a doctoral program, and doctoral degree completion. Each of the five areas of analysis is made up of specific variables that contribute to a better understanding of the doctoral student experience. The framework suggests that "personal and academic backgrounds, along with other acquired benefits, contribute to the quality of students' experiences and outcomes" (p. 27). The book does a great job of providing detail about the variables, conceptual analytical framework, data analysis, and study findings in ways that are informative and thorough yet never dry. Given the expansiveness of the project, it is not feasible in a book review to provide a detailed account of the findings. The book generates many "new answers and new questions" about doctoral education that merit ongoing consideration. …

Resuspension of Sediment by Bottom Trawling in the Gulf of Maine and Potential Geochemical Consequences

Abstract: The benthic environment of the Gulf of Maine is characterized by a thick and basin-wide nepheloid layer, classically defined as a near-bottom region of permanent sediment resuspension. The high frequency of commercial bottom trawling in particular regions of the Gulf of Maine, documented by records compiled by the National Marine Fisheries Service, may strongly affect measured resuspension fluxes and contribute to the maintenance of the nepheloid layer. Indirect evidence of the effects of bottom trawling on sediment resuspen- sion is observed in the seasonal collection of large, benthic infaunal worms, along with substantial amounts of resuspended bottom sediment, in a sediment trap deployed 25 m off the bottom in the western gulf region of Wilkinson Basin. These collections appear to be coincident with seasonal periods of intensive bottom trawl- ing in this area. By comparison, the western gulf region of Jordan Basin is typified by significantly reduced annual bottom-trawling activity, and very few infaunal worms are found in the seasonal collections of a sed- iment trap located 25-30 m off the bottom. The extent to which trawling-induced bottom sediment excava- tion and resuspension occurs has important implications for regional nutrient budgets in terms of the input of sedimentary nitrogen and silica into the water column via this anthropogenic activity. Sediment mixing and frequent bottom disturbance from trawling activity may also produce changes in the successional orga- nization of soft-sediment infaunal communities. The potential effects of trawling require serious examination and quantification to accurately determine the impact of such anthropogenic activity on the benthic ecosys- tems of continental margin environments.