Influence of viscoelasticity and interfacial slip on acoustic wave sensors

Acoustic wave devices with shear horizontal displacements, such as quartz crystal microbalances (QCM) and shear horizontally polarised surface acoustic wave (SH-SAW) devices provide sensitive probes of changes at solid-solid and solid- liquid interfaces. Increasingly the surfaces of acoustic wave devices are being chemically or physically modified to alter surface adhesion or coated with one or more layers to amplify their response to any change of mass or material properties. In this work, we describe a model that provides a unified view of the modification in the shear motion in acoustic wave systems by multiple finite thickness loadings of viscoelastic fluids. This model encompasses QCM and other classes of acoustic wave devices based on a shear motion of the substrate surface and is also valid whether the coating film has a liquid or solid character. As a specific example, the transition of a coating from liquid to solid is modelled using a single relaxation time Maxwell model. The correspondence between parameters from this physical model and parameters from alternative acoustic impedance models is given explicitly. The characteristic changes in QCM frequency and attenuation as a function of thickness are illustrated for a single layer device as the coating is varied from liquid-like to that of an amorphous solid. Results for a double layer structure are given explicitly and the extension of the physical model to multiple layers is described

Toward identification of larval sailfish (Istiophorus platypterus), white marlin (Tetrapturus albidus), and blue marlin (Makaira nigricans) in the western North Atlantic Ocean*

The identification of larval istiophorid billfishes from the western North Atlantic Ocean has long been problematic. In the present study, a molecular technique was used to positively identify 27 larval white marlin (Tetrapturus albidus), 96 larval blue marlin (Makaira nigricans), and 591 larval sailfish (Istiophorus platypterus) from the Straits of Florida and the Bahamas. Nine morphometric measurements were taken for a subset of larvae (species known), and lower jaw pigment patterns were recorded on a grid. Canonical variates analysis (CVA) was used to reveal the extent to which the combination of morphometric, pigment pattern, and month of capture information was diagnostic to species level. Linear regression revealed species-specific relationships between the ratio of snout length to eye orbit diameter and standard length (SL). Confidence limits about these relationships served as defining characters for sailfish >10 mm SL and for blue and white marlin >17 mm SL. Pigment pattern analysis indicated that 40% of the preflexion blue marlin examined possessed a characteristic lower jaw pigment pattern and that 62% of sailfish larvae were identifiable by lower jaw pigments alone. An identification key was constructed based on pigment patterns, month of capture, and relationships between SL and the ratio of snout length to eye orbit diameter. The key yielded identifications for 69.4% of 304 (blind sample) larvae used to test it; only one of these identifications was incorrect. Of the 93 larvae that could not be identified by the key, 71 (76.3%) were correctly identified with CVA. Although identif ication of certain larval specimens may always require molecular techniques, it is encouraging that the majority (92.4%) of istiophorid larvae examined were ultimately identifiable from external characteristics alone

The MPCP Longitudinal Educational Growth Study Third Year Report

This is the third-year report in a five-year evaluation of the Milwaukee Parental Choice Program (MPCP). The MPCP, which began in 1990, provides government-funded vouchers for low-income children to attend private schools in the City of Milwaukee. The maximum voucher amount in 2008-09 was $6,607, and approximately 20,000 children used a voucher to attend either secular or religious private schools. The MPCP is the oldest and largest urban school voucher program in the United States. This evaluation was authorized by Wisconsin Act 125 enacted in 2005

Translation inhibition by rocaglates activates a species-specific cell death program in the emerging fungal pathogen Candida auris

Fungal infections are a major contributor to infectious disease-related deaths worldwide. Recently, global emergence of the fungal pathogen Candida auris has caused considerable concern because most C. auris isolates are resistant to fluconazole, the most commonly administered antifungal, and some isolates are resistant to drugs from all three major antifungal classes. To identify novel agents with bioactivity against C. auris, we screened 2,454 compounds from a diversity-oriented synthesis collection. Of the five hits identified, most shared a common rocaglate core structure and displayed fungicidal activity against C. auris These rocaglate hits inhibited translation in C. auris but not in its pathogenic relative Candida albicans Species specificity was contingent on variation at a single amino acid residue in Tif1, a fungal member of the eukaryotic initiation factor 4A (eIF4A) family of translation initiation factors known to be targeted by rocaglates. Rocaglate-mediated inhibition of translation in C. auris activated a cell death program characterized by loss of mitochondrial membrane potential, increased caspase-like activity, and disrupted vacuolar homeostasis. In a rocaglate-sensitized C. albicans mutant engineered to express translation initiation factor 1 (Tif1) with the variant amino acid that we had identified in C. auris, translation was inhibited but no programmed cell death phenotypes were observed. This surprising finding suggests divergence between these related fungal pathogens in their pathways of cellular responses to translation inhibition. From a therapeutic perspective, the chemical biology that we have uncovered reveals species-specific vulnerability in C. auris and identifies a promising target for development of new, mechanistically distinct antifungals in the battle against this emerging pathogen. IMPORTANCE Emergence of the fungal pathogen Candida auris has ignited intrigue and alarm within the medical community and the public at large. This pathogen is unusually resistant to antifungals, threatening to overwhelm current management options. By screening a library of structurally diverse molecules, we found that C. auris is surprisingly sensitive to translation inhibition by a class of compounds known as rocaglates (also known as flavaglines). Despite the high level of conservation across fungi in their protein synthesis machinery, these compounds inhibited translation initiation and activated a cell death program in C. auris but not in its relative Candida albicans Our findings highlight a surprising divergence across the cell death programs operating in Candida species and underscore the need to understand the specific biology of a pathogen in attempting to develop more-effective treatments against it.Published versio

Mass and elite aspects of educational systems : a comparative analysis.

Chapter One identifies areas of actual and potential\ud confusion in the analysis of 'mass' and 'elite' education systems.\ud It attempts to clarify the area of enquiry. The chapter concludes\ud with a statement of a 'problem'. The problem is the relation\ud between rapidly changing types of school and higher education\ud institutions, and 'theories of general education'.\ud Chapter Two continues the task of clarification by\ud selecting and explaining the techniques of enquiry which are used\ud to clarify the problem in England. The techniques are reviewed\ud and the tradition within which the analysis is located is briefly\ud identified. This chapter concludes the initial phase of problem\ud analysis.\ud Chapter Three undertakes the identification of the\ud problem in different contexts, i.e. in four countries. It notes\ud variations in the patternings of the problem. It considers\ud selected aspects of the internal dynamics of educational systems\ud in their relation to the problem.\ud Chapter Four is a short abstract statement of the ways\ud in which theories in general education are sustained; and thus\ud potentially changed.\ud Chapter Five offers some comment on the possibilities\ud of changing the 'theory of general education' in England.\ud 3\ud ACKNOWLEDGEMENTS\ud I have been fortunate. In my formal education, I have\ud been taught by four remarkable teachers. Of these, two have been\ud Professor and Head of the Comparative Education Department at the\ud University of London Institute of Education.\ud The impact of these two men, Professor Lauwerys and\ud Professor Holmes on comparative education students, for a period of\ud time which is now approaching forty years, has been extensive and\ud intensive. Extensive, in that their students are now teachers of\ud comparative education all over the world. Intensive, in that the\ud intellectual attraction of their teaching has often been so strong\ud as to change the ways in which individuals see their lives. They\ud had this effect on me. I thank them for their teaching.\ud My particular debt to Professor Holmes will be clear, to\ud specialists in comparative education, in the pages that follow. Here\ud I would like to acknowledge a crucial departmental institution: the\ud Holmes' research seminar which has been held fortnightly for many\ud years now. The seminar is a normal part of the life of a research\ud student in the department. Everyone attends, and regularly. I\ud suppose most people attend because, like me, they find that their\ud thought processes in difficult comparative analyses are, when fast,\ud not rigorous enough for the seminar; and when rigorous, too slow.\ud One learns. The learning is 'cumulative. It is possible to meet the\ud standards expected in the seminar; occasionally. For the pressure to\ud meet those standards, for the freely given energy of the teaching\ud process, and for the example of how comparative education work\ud might be well done, I acknowledge with great pleasure a permanent\ud debt.\u