Talking about interaction*

© 2019 Elsevier Ltd Recent research has exposed disagreements over the nature and usefulness of what may (or may not) be Human–Computer Interaction's fundamental phenomenon: ‘interaction’. For some, HCI's theorising about interaction has been deficient, impacting its capacity to inform decisions in design, suggesting the need either to perform first-principles definition work or broader administrative clarification and formalisation of the multitude of formulations of the concepts of interaction and their particular uses. For others, there remain open questions over the continued relevance of certain ‘versions’ of interaction as a useful concept in HCI at all. We pursue a different perspective in this paper, reviewing how HCI treats interaction through examining its ‘conceptual pragmatics’ within HCI's discourse. We argue that articulations of the concepts of interaction can be a site of productive conflict for HCI that for many reasons may resist attempts of formalisation as well as attempts to dispense with them. The main contribution of this paper is in specifying how we might go about talking of interaction and the value of interaction language as promiscuous concepts

O stars and Wolf-Rayet stars

Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented

The M-type stars

The papers in this volume cover the following topics: (1) basic properties and photometric variability of M and related stars; (2) spectroscopy and nonthermal processes; (3) circumstellar radio molecular lines; (4) circumstellar shells, the formation of grains, and radiation transfer; (5) mass loss; (6) circumstellar chemistry; (7) thermal atmospheric models; (8) quasi-thermal models; (9) observations on the atmospheres of M dwarfs; and (1) theoretical work on M dwarfs

Looking forward to making predictions

As described in the preceding pages, since the BGS was established in 1835, the British population has coped with many challenges. These have ranged from finding resources to fuel the Industrial Revolution, understanding and combating water-borne diseases such as typhoid, the threat of invasion and aerial bombardment, through to modern-day environmental problems and climate change. To help deal with these problems, decisionmakers from governments and other organisations have required our help and advice

An Analysis of Income Smoothing

The purpose of this research is to investigate various income smoothing detection methods.  Using a SEC identified sample of firms that were charged with violations of GAAP due to earnings manipulations and a matched sample of firms, we test seven popular models to determine which provide the best identification of income smoothing. The results indicate that, while there is no significant difference between six of the seven detection methods, the Dechow et al. method provides different results. We found the Dechow, et al. method to be significantly different in detecting smoothing, although this method was different only because it detected 25 out of the total of 28 firms as income smoothing firms.  Our results indicate that many more of the matched sample appear to be income smoothing firms and fewer of the SEC sample appear to smooth income.We think these results indicate that researchers should be cautious in their conclusions.  While these methods provide differing results, they also provide insight into the various aspects of income smoothing and the resulting effect on earnings.  Therefore this research has provided insight into the different income smoothing detection models, while also indicating that different methods are not equally suited to determine all forms of income smoothing.  The appropriate methodology must be chosen to address the specific aspects of income smoothing or earnings management that the researcher is investigating

HY5 is not integral to light mediated stomatal development in Arabidopsis.

Light is a crucial signal that regulates many aspects of plant physiology and growth including the development of stomata, the pores in the epidermal surface of the leaf. Light signals positively regulate stomatal development leading to changes in stomatal density and stomatal index (SI; the proportion of cells in the epidermis that are stomata). Both phytochrome and cryptochrome photoreceptors are required to regulate stomatal development in response to light. The transcription factor ELONGATED HYPOCOTYL 5 (HY5) is a key regulator of light signalling, acting downstream of photoreceptors. We hypothesised that HY5 could regulate stomatal development in response to light signals due to the putative presence of HY5 binding sites in the promoter of the STOMAGEN (STOM) gene, which encodes a peptide regulator of stomatal development. Our analysis shows that HY5 does have the potential to regulate the STOM promoter in vitro and that HY5 is expressed in both the epidermis and mesophyll. However, analysis of hy5 and hy5 hyh double mutants (HYH; HY5-HOMOLOG), found that they had normal stomatal development under different light conditions and the expression of stomatal developmental genes was not perturbed following light shift experiments. Analysis of stable lines overexpressing HY5 also showed no change in stomatal development or the expression of stomatal developmental genes. We therefore conclude that whilst HY5 has the potential to regulate the expression of STOM, it does not have a major role in regulating stomatal development in response to light signals

The Stille reaction in natural product synthesis : the total synthesis of 14,15-anhydrovirginiamycin M2

The thesis describes synthetic studies directed towards the total synthesis of 14,15-anhydrovirginiamycin M2, a streptogramin antibiotic of the virginiamycin family. This novel natural product shows pronounced antibacterial activity against a wide range of potentially lethal bacteria. The Introduction summarises the main therapeutic uses, isolation, structural determination, biosynthesis, and mode of action of the virginiamycins. Also included is a review of synthetic approaches which have been described to access these and similar streptogramin antibiotics by other research groups. A review of the intramolecular Stille coupling reaction within organic synthesis incorporating the most prominent examples of its use over the past ten years in the synthesis of natural products is also presented. The Discussion part of the thesis contains details of our synthetic studies on suitable model systems, including: a study of conjugated triene formation via Stille chemistry; peptidic bond formation; and special reference to the problems involved in the synthesis of the 2,4-disubstituted oxazole contained within the virginiamycins. The studies culminate with a description of the first total synthesis of 14,15- anhydrovirginiamycin M2, which proved identical to the natural product obtained from a Streptomyces fermentation process. A full description of the experimental work carried out, and spectroscopic data for all compounds synthesised, is contained in an Experimental section

Contributions of Ca^(2+)-Independent Thin Filament Activation to Cardiac Muscle Function

Although Ca^(2+) is the principal regulator of contraction in striated muscle, in vitro evidence suggests that some actin-myosin interaction is still possible even in its absence. Whether this Ca^(2+)-independent activation (CIA) occurs under physiological conditions remains unclear, as does its potential impact on the function of intact cardiac muscle. The purpose of this study was to investigate CIA using computational analysis. We added a structurally motivated representation of this phenomenon to an existing myofilament model, which allowed predictions of CIA-dependent muscle behavior. We found that a certain amount of CIA was essential for the model to reproduce reported effects of nonfunctional troponin C on myofilament force generation. Consequently, those data enabled estimation of ΔG_(CIA), the energy barrier for activating a thin filament regulatory unit in the absence of Ca^(2+). Using this estimate of ΔG_(CIA) as a point of reference (∼7 kJ mol^(−1)), we examined its impact on various aspects of muscle function through additional simulations. CIA decreased the Hill coefficient of steady-state force while increasing myofilament Ca^(2+) sensitivity. At the same time, CIA had minimal effect on the rate of force redevelopment after slack/restretch. Simulations of twitch tension show that the presence of CIA increases peak tension while profoundly delaying relaxation. We tested the model’s ability to represent perturbations to the Ca^(2+) regulatory mechanism by analyzing twitch records measured in transgenic mice expressing a cardiac troponin I mutation (R145G). The effects of the mutation on twitch dynamics were fully reproduced by a single parameter change, namely lowering ΔG_(CIA) by 2.3 kJ mol^(−1) relative to its wild-type value. Our analyses suggest that CIA is present in cardiac muscle under normal conditions and that its modulation by gene mutations or other factors can alter both systolic and diastolic function

The Stille reaction in natural product synthesis : the total synthesis of 14,15-anhydrovirginiamycin M2

The thesis describes synthetic studies directed towards the total synthesis of 14,15-anhydrovirginiamycin M2, a streptogramin antibiotic of the virginiamycin family. This novel natural product shows pronounced antibacterial activity against a wide range of potentially lethal bacteria. The Introduction summarises the main therapeutic uses, isolation, structural determination, biosynthesis, and mode of action of the virginiamycins. Also included is a review of synthetic approaches which have been described to access these and similar streptogramin antibiotics by other research groups. A review of the intramolecular Stille coupling reaction within organic synthesis incorporating the most prominent examples of its use over the past ten years in the synthesis of natural products is also presented. The Discussion part of the thesis contains details of our synthetic studies on suitable model systems, including: a study of conjugated triene formation via Stille chemistry; peptidic bond formation; and special reference to the problems involved in the synthesis of the 2,4-disubstituted oxazole contained within the virginiamycins. The studies culminate with a description of the first total synthesis of 14,15- anhydrovirginiamycin M2, which proved identical to the natural product obtained from a Streptomyces fermentation process. A full description of the experimental work carried out, and spectroscopic data for all compounds synthesised, is contained in an Experimental section