Vertical axis wind rotors: Status and potential

The design and application of a vertical axis wind rotor is reported that operates as a two stage turbine wherein the wind impinging on the concave side is circulated through the center of the rotor to the back of the convex side, thus decreasing what might otherwise be a high negative pressure region. Successful applications of this wind rotor to water pumps, ship propulsion, and building ventilators are reported. Also shown is the feasibility of using the energy in ocean waves to drive the rotor. An analysis of the impact of rotor aspect ratio on rotor acceleration shows that the amount of venting between rotor vanes has a very significant effect on rotor speed for a given wind speed

The structure of latherin, a surfactant allergen protein from horse sweat and saliva

Latherin is a highly surface-active allergen protein found in the sweat and saliva of horses and other equids. Its surfactant activity is intrinsic to the protein in its native form, and is manifest without associated lipids or glycosylation. Latherin probably functions as a wetting agent in evaporative cooling in horses, but it may also assist in mastication of fibrous food as well as inhibition of microbial biofilms. It is a member of the PLUNC family of proteins abundant in the oral cavity and saliva of mammals, one of which has also been shown to be a surfactant and capable of disrupting microbial biofilms. How these proteins work as surfactants while remaining soluble and cell membrane-compatible is not known. Nor have their structures previously been reported. We have used protein nuclear magnetic resonance spectroscopy to determine the conformation and dynamics of latherin in aqueous solution. The protein is a monomer in solution with a slightly curved cylindrical structure exhibiting a ‘super-roll’ motif comprising a four-stranded anti-parallel β-sheet and two opposing α-helices which twist along the long axis of the cylinder. One end of the molecule has prominent, flexible loops that contain a number of apolar amino acid side chains. This, together with previous biophysical observations, leads us to a plausible mechanism for surfactant activity in which the molecule is first localized to the non-polar interface via these loops, and then unfolds and flattens to expose its hydrophobic interior to the air or non-polar surface. Intrinsically surface-active proteins are relatively rare in nature, and this is the first structure of such a protein from mammals to be reported. Both its conformation and proposed method of action are different from other, non-mammalian surfactant proteins investigated so far

Training Statisticians To Be Alert To The Dangers Of Misapplying Statistical Methods

Statisticians are faced with a variety of challenges. Their ability to cope successfully with these challenges depends, in large part, on the quality of their training. It is not the purpose of this article to present a comprehensive training plan that will overhaul the standard curriculum a statistician might follow under current training regimens (i.e., in a degree program). Rather, the objective is to point out important areas that appear to be under-represented in standard curricula and correspondingly overlooked too often in practice. The hope is that these areas might be better integrated into the training of the next generation of statisticians

A Socratic Dialogue

Socrates has found some aspects of medical biostatistics a bit confusing, and wishes to discuss some of these issues with Simplicio, a prominent medical researcher. This Socratic dialogue will shed some light on the errant use of parametric analyses in clinical trials

Elementary Principal Perceptions of the Tennessee Educator Acceleration Model

The Tennessee Educator Acceleration Model (TEAM) had been in a state of reform since being awarded the Race to the Top Grant. Few teachers admit that an evaluation influenced them significantly; additionally, few administrators agreed that when they evaluated a teacher, it did not significantly affect the teacher or students. The purpose of this qualitative study was to determine the perceptions of building‑level principals regarding the effectiveness (i.e., increased teacher participation and quality) and efficiency (i.e., produces the required results) of the TEAM in regard to teacher evaluations. Four elementary school principals from East Tennessee participated in the study. The researcher provided data from this study to inform stakeholders of strengths and weaknesses of the state evaluation model. Additionally, the researcher used the data to provide recommendations for improvements to the TEAM model and to identify support principals needed to adapt their leadership style to effectively execute TEAM mandates. The research revealed that the principals believed the model was a strong one that was research based; however, the model could prove to be ineffective in the delivery and inefficient in the follow‑through if the proper supports were not in place

An Empirical Demonstration of the Need for Exact Tests

The robustness of parametric analyses is rarely questioned or qualified. Robustness, generally understood, means the exact and approximate p-values will lie on the same side of alpha for any reasonable data set; and 1) any data set would qualify as reasonable and 2) robustness holds universally, for all alpha levels and approximations. For this to be true, the approximation would need to be perfect all of the time. Any discrepancy between the approximation and the exact p-value, for any combination of alpha level and data set, would constitute a violation. Clearly, this is not true, and when confronted with this reality, the “No True Scotsman” fallacy is often invoked with the declaration it must have been a pathological data set, as if this would obviate the responsibility to select an appropriate research method. Ideally, a method would be selected because it is optimal, or at least appropriate, without needing special pleading, but judging by how often approximations are used when the exact values they are trying to approximate are readily available, current trends do not come close to this ideal. One possible explanation might be that there is not much information available on data sets for which the approximations fail miserably. Examples are presented in an effort to clarify the need for exact analyses

Thrift competition and its impact on financial institution mergers and acquisitions in the Richmond, Virginia RMA

Commercial banking has been subject to antitrust review for only a few decades. In 1948, the Transamerica Corporation was charged by the Board of Governors of the Federal Reserve System with a violation of Section 7 of the Clayton Act when it acquired controlling interest in several independent banks in California (1). At the time of the acquisitions, the banks in question were in direct competition with one or more oof the banks already controlled by Transamerica Corporation. Moreover, Transamerica Corporation held a major interest in Bank of America. This unique case ignited a fear of probable banking concentration and potential banking monopoly. The debate about concentrations in banking led to a Congressional inquiry and a subsequent staff report entitled Bank Mergers and Concentration of Banking Facilities. The report stated the reduction in the number of banks nationwide had lessened competition in many banking communities and recommended remedial legislation to ensure that government banking authorities would study the effect of such merger and acquisitions prior to approving any sort of bank merger of consolidation. (2

Frog foams and natural protein surfactants

Foams and surfactants are relatively rare in biology because of their potential to harm cell membranes and other delicate tissues. However, in recent work we have identified and characterized a number of natural surfactant proteins found in the foam nests of tropical frogs and other unusual sources. These proteins, and their associated foams, are relatively stable and bio-compatible, but with intriguing molecular structures that reveal a new class of surfactant activity. Here we review the structures and functional mechanisms of some of these proteins as revealed by experiments involving a range of biophysical and biochemical techniques, with additional mechanistic support coming from more recent site-directed mutagenesis studies

Examining Trust in Information Technology Artifacts : The Effects of System Quality and Culture.

The topic of trust in information technology (IT) artifacts has piqued interest among researchers, but studies of this form of trust are not definitive regarding which factors contribute to it the most. Our study empirically tests a model of trust in IT artifacts that increases our understanding in two ways. First, it sets forth two previously unexamined system quality constructs-navigational structure and visual appeal. We found that both of these system quality constructs significantly predict the extent to which users place trust in mobile commerce technologies. Second, our study considers the effect of culture by comparing the trust of French and American potential users in m- commerce technologies. We found that not only does culture directly affect user trust in IT artifacts but it also moderates the extent to which navigational structure affects this form of trust. These findings show that system quality and culture significantly affect trust in the IT artifact and point to rich possibilities for future research in these areas.Commerce mobile; Systems use; System quality; Navigational structure; Mobile commerce; M-commerce portals;