Extractable nitrogen and microbial community structure respond to grassland restoration regardless of historical context and soil composition.

Grasslands have a long history of invasion by exotic annuals, which may alter microbial communities and nutrient cycling through changes in litter quality and biomass turnover rates. We compared plant community composition, soil chemical and microbial community composition, potential soil respiration and nitrogen (N) turnover rates between invaded and restored plots in inland and coastal grasslands. Restoration increased microbial biomass and fungal : bacterial (F : B) ratios, but sampling season had a greater influence on the F : B ratio than did restoration. Microbial community composition assessed by phospholipid fatty acid was altered by restoration, but also varied by season and by site. Total soil carbon (C) and N and potential soil respiration did not differ between treatments, but N mineralization decreased while extractable nitrate and nitrification and N immobilization rate increased in restored compared with unrestored sites. The differences in soil chemistry and microbial community composition between unrestored and restored sites indicate that these soils are responsive, and therefore not resistant to feedbacks caused by changes in vegetation type. The resilience, or recovery, of these soils is difficult to assess in the absence of uninvaded control grasslands. However, the rapid changes in microbial and N cycling characteristics following removal of invasives in both grassland sites suggest that the soils are resilient to invasion. The lack of change in total C and N pools may provide a buffer that promotes resilience of labile pools and microbial community structure

Polarization Switching Dynamics Governed by Thermodynamic Nucleation Process in Ultrathin Ferroelectric Films

A long standing problem of domain switching process - how domains nucleate - is examined in ultrathin ferroelectric films. We demonstrate that the large depolarization fields in ultrathin films could significantly lower the nucleation energy barrier (U*) to a level comparable to thermal energy (kBT), resulting in power-law like polarization decay behaviors. The "Landauer's paradox": U* is thermally insurmountable is not a critical issue in the polarization switching of ultrathin ferroelectric films. We empirically find a universal relation between the polarization decay behavior and U*/kBT.Comment: 5 pages, 4 figure

Toward iconic-based information technology and application control exception messages: Working paper series--07-09

Users of information technology (IT) commonly encounter exception messages during their interactions with application programs. Exception messages are an important element in accounting application controls which address exposures within specific computer application programs such as payroll, sales processing, and cash disbursements. Exception messages are similar in purpose to the warning messages that appear on consumer products and equipment (e.g., cigarettes, power tools, etc.), in various work environments (e.g., around machinery), and on chemicals. This manuscript reviews the normative elements and information that are included in product, chemical, and environment warnings and proposes that these elements and information should also be included in IT and application control exception messages. It is argued that including these elements will increase the effectiveness, informativeness, and consistency of exception messages. Additionally, we report the results of an experiment carried out to determine if IT and application control exception messages designed to conform to the normative elements, by specifically including descriptive icons, improves user interactions. The results of the experiment confirm that user's behavioral compliance increases when interacting with a system that incorporates iconic-based exception messages

The effect of qualitative expressions of magnitude in the letter to shareholders on investors' perceptions of earnings performance: Working paper series--03-18

Annual reports issued by publicly traded firms are important documents for communicating the financial performance of a company. In addition to the financial statements, annual reports contain non-numerical information (i.e., written expressions). The letter to shareholders is typically the first non-numerical item representing management's communication that a reader comes to in an annual report. The primary content of the letter to shareholders is a series of written expressions used to describe the company's financial situation. We report how readers' perceptions are influenced by one type of written expression often found in the letter to shareholders: Qualitative expressions of magnitude (e.g., "minimal," "moderate" or "sizable") used to describe the results of operations. Top management (e.g., presidents) very often uses qualitative expressions of magnitude in the letter to shareholders to describe the quantitative financial performance of the company found in the accompanying financial statements. Holding the actual percentage change in corporate earnings and other contextual factors constant, we find that the type of expression used in the letter to shareholders does influence readers' perception of financial performance reported in the financial statements. In addition, we find evidence that less sophisticated investors are influenced more by the use of qualitative expressions of magnitude

Observation of inhomogeneous domain nucleation in epitaxial Pb(Zr,Ti)O3 capacitors

We investigated domain nucleation process in epitaxial Pb(Zr,Ti)O3 capacitors under a modified piezoresponse force microscope. We obtained domain evolution images during polarization switching process and observed that domain nucleation occurs at particular sites. This inhomogeneous nucleation process should play an important role in an early stage of switching and under a high electric field. We found that the number of nuclei is linearly proportional to log(switching time), suggesting a broad distribution of activation energies for nucleation. The nucleation sites for a positive bias differ from those for a negative bias, indicating that most nucleation sites are located at ferroelectric/electrode interfaces

Information technology exception messages - An investigation of compliance with the normative standards of warnings: Working paper series--07-08

Users of information technology (IT) frequently encounter "exception messages" during their interactions with computing systems. Exception messages are important points of communication with users of IT and are similar in purpose to warning messages that appear on consumer products and equipment (e.g., cigarettes, power tools, etc.), in various work environments (e.g., around machinery), and on chemicals. This study reviews the normative elements and information that are included in product, chemical, and environment warnings and proposes that these elements and information should also be included in IT exception messages. Also reported are the results of an investigation of a sample of exception messages to determine their degree of compliance with the proposed elements. Results indicate that, relative to normative prescriptions established in the literature on warnings, IT exception messages lack descriptive content

From the Arctic to the Tropics: A Thematic Analysis of Teacher Candidates’ Reflections of Two Cross-Cultural Programs

This study describes how one university prepares culturally responsive teacher candidates through Alaska and Thailand cross-cultural summer study trips. The study addressed the impact of the Alaska and Thailand cross-cultural experiences on teacher candidates as described in their reflective writings. The reflections addressed their socialization and depth of understanding and appreciation of children and adults from another culture. The authors looked for parallel themes that emerged as characteristics of both experiences

Direct Measurement of the Fermi Energy in Graphene Using a Double Layer Structure

We describe a technique which allows a direct measurement of the relative Fermi energy in an electron system using a double layer structure, where graphene is one of the two layers. We illustrate this method by probing the Fermi energy as a function of density in a graphene monolayer, at zero and in high magnetic fields. This technique allows us to determine the Fermi velocity, Landau level spacing, and Landau level broadening in graphene. We find that the N=0 Landau level broadening is larger by comparison to the broadening of upper and lower Landau levels.Comment: 5 pages, 4 figure

The perceived hazard of earcons in information technology exception messages: The effect of musical dissonance: Working paper series--10-03

Users of information technology (IT) commonly encounter exception messages during their interactions with application programs to signal a computing problem or error. Exception messages often are accompanied by earcons which are aural messages of a musical nature used in the human-computer interface to provide information and feedback about some computer object, operation, or interaction. Utilizing the notion of musical dissonance earcons were designed that vary as to their degree of aural disagreeableness along a rank order scale. It is hypothesized that in the context of IT exception messages earcons with a higher degree of musical dissonance (aural disagreeableness) would be perceived as communicating a higher degree of hazard associated with the underlying computing problem signaled by an exception message. Participants rated the degree of hazard of each earcon presented in a random order in an experiment. Results of the data analysis indicate partial support of the hypothesis. The implications are that it may be possible to increase the degree of hazard matching in IT environments by designing earcons that accompany exception messages to communicate different levels of perceived hazard of an underlying computer problem