The hormones of invertebrates

Thesis (M.A.)--Boston University, 193

The institutional character of computerized information systems

We examine how important social and technical choices become part of the history of a computer-based information system (CB/SJ and embedded in the social structure which supports its development and use. These elements of a CBIS can be organized in specific ways to enhance its usability and performance. Paradoxically, they can also constrain future implementations and post-implementations.We argue that CBIS developed from complex, interdependent social and technical choices should be conceptualized in terms of their institutional characteristics, as well as their information-processing characteristics. The social system which supports the development and operation of a CBIS is one major element whose institutional characteristics can effectively support routine activities while impeding substantial innovation. Characterizing CBIS as institutions is important for several reasons: (1) the usability of CBIS is more critical than the abstract information-processing capabilities of the underlying technology; (2) CBIS that are well-used and have stable social structures are more difficult to replace than those with less developed social structures and fewer participants; (3) CBIS vary from one social setting to another according to the ways in which they are organized and embedded in organized social systems. These ideas are illustrated with the case study of a failed attempt to convert a complex inventory control system in a medium-sized manufacturing firm

Inelastic Dark Matter at the LHC Lifetime Frontier: ATLAS, CMS, LHCb, CODEX-b, FASER, and MATHUSLA

Visible signals from the decays of light long-lived hidden sector particles have been extensively searched for at beam dump, fixed-target, and collider experiments. If such hidden sectors couple to the Standard Model through mediators heavier than $\sim 10$ GeV, their production at low-energy accelerators is kinematically suppressed, leaving open significant pockets of viable parameter space. We investigate this scenario in models of inelastic dark matter, which give rise to visible signals at various existing and proposed LHC experiments, such as ATLAS, CMS, LHCb, CODEX-b, FASER, and MATHUSLA. These experiments can leverage the large center of mass energy of the LHC to produce GeV-scale dark matter from the decays of dark photons in the cosmologically motivated mass range of $\sim 1-100$ GeV. We also provide a detailed calculation of the radiative dark matter-nucleon/electron elastic scattering cross section, which is relevant for estimating rates at direct detection experiments.Comment: 21 pages, 9 figure

Structure and Dynamics of the Quasi-Liquid Layer at the Surface of Ice from Molecular Simulations

We characterized the structural and dynamical properties of the quasi-liquid layer (QLL) at the surface of ice by molecular dynamics simulations with a thermodynamically consistent water model. Our simulations show that for three low-index ice surfaces only the outermost molecular layer presents short-range and mid-range disorder and is diffusive. The onset temperature for normal diffusion is much higher than the glass temperature of supercooled water, although the diffusivity of the QLL is higher than that of bulk water at the corresponding temperature. The underlying subsurface layers impose an ordered template, which produces a regular patterning of the ice/water interface at any temperature, and is responsible for the major differences between QLL and bulk water, especially for what concern the dynamics and the mid-range structure of the hydrogen-bonded network. Our work highlights the need of a holistic approach to the characterization of QLL, as a single experimental technique may probe only one specific feature, missing part of the complexity of this fascinating system.Comment: 6 Figure

Information and Communication Technologies and Informal Scholarly Communication: A Review of the Social Oriented Research

This article reviews and analyzes findings from research on computer mediated informal scholarly communication. Ten empirical research papers, which show the effects and influences of information & communication technologies (ICTs), or the effects of social contexts on ICTs use in informal scholarly communication, were analyzed and compared. Types of ICTs covered in those studies include e-mails, collaboratories, and electronic forums. The review shows that most of the empirical studies examined the ICTs use effects or consequences. Only a few studies examined the social shaping of ICTs and ICT uses in informal scholarly communication. Based on comparisons of the empirical findings this article summarizes the ICT use effects/consequences as identified in the studies into seven categories and discusses their implications

Probabilistic Approach for better Buckling Knock-down Factors of CFRP Cylindrical Shells - Tests and Analyses

The industry in the fields of civil and mechanical engineering, and in particular of aerospace demands for significantly reduced development and operating costs. Reduction of structural weight at safe design is one avenue to achieve this objective. The running ESA (European Space Agency) study Probabilistic Aspects of Buckling Knock Down Factors – Tests and Analyses contributes to this goal by striving for an improved buckling knock-down factor (the ratio of buckling loads of imperfect and perfect structures) for unstiffened CFRP (carbon fiber reinforce plastics) cylindrical shells, and by validation of the linear and non-linear buckling simulations based on test results. DLR is acting as study contractor. The paper presents an overview about the DLR buckling tests, the measurement setup and the buckling simulations which are done so far, and gives an outlook to the results which are expected until the end of the running project

Researching scholarship in the age of the internet

In this paper I review current debates about the nature of scholarship in higher education (following Boyer 1990) and the impact of digital communication practices on its role in research and teaching (e.g. Borgman 2007, Pearce et al 2010), and discuss a methodological framework for researching these issues, drawing on work in Literacies for Learning (Ivani? et al 2007) and Socio-technical Interaction (Kling et al 2003)