Automatic infrasound signal detection using the Hough transform

The Hough transform is a mathematical device that allows the retrieval of parametric curve information from binary-pixelated data in the presence of noise. This slope-intercept transform maps each point in the image space S into a straight line in parameter space P and has the very useful property that all points in S that lie along the same straight-line map to the same number of straight lines in P with a common intersection point. Thus with a suitable counting procedure, the problem of extended straight-line detection in noisy pixelated data becomes one of local peak finding, a problem that may be substantially more tractable. In this study, an algorithm that utilizes the Hough transform for the detection of signals in International Monitoring System style infrasonic array data by seeking periods of constant backazimuth that are associated with coherent acoustic signals is described. A system of synthetic signal implants is used to assess the performance of the detection algorithm by generating a set of pseudo Receiver Operator Characteristic curves. A feature of the detection algorithm is the ability to accommodate full three-dimensional array geometry

Speract induces calcium oscillations in the sperm tail

Sea urchin sperm motility is modulated by sperm-activating peptides. One such peptide, speract, induces changes in intracellular free calcium concentration ([Ca2+]i). High resolution imaging of single sperm reveals that speract-induced changes in [Ca2+]i have a complex spatiotemporal structure. [Ca2+]i increases arise in the tail as periodic oscillations; [Ca2+]i increases in the sperm head lag those in the tail and appear to result from the summation of the tail signal transduction events. The period depends on speract concentration. Infrequent spontaneous [Ca2+]i transients were also seen in the tail of unstimulated sperm, again with the head lagging the tail. Speract-induced fluctuations were sensitive to membrane potential and calcium channel blockers, and were potentiated by niflumic acid, an anion channel blocker. 3-isobutyl-1-methylxanthine, which potentiates the cGMP/cAMP-signaling pathways, abolished the [Ca2+]i fluctuations in the tail, leading to a very delayed and sustained [Ca2+]i increase in the head. These data point to a model in which a messenger generated periodically in the tail diffuses to the head. Sperm are highly polarized cells. Our results indicate that a clear understanding of the link between [Ca2+]i and sperm motility will only be gained by analysis of [Ca2+]i signals at the level of the single sperm

Software for Remote Monitoring of Space-Station Payloads

Telescience Resource Kit (TReK) is a suite of application programs that enable geographically dispersed users to monitor scientific payloads aboard the International Space Station (ISS). TReK provides local ground support services that can simultaneously receive, process, record, playback, and display data from multiple sources. TReK also provides interfaces to use the remote services provided by the Payload Operations Integration Center which manages all ISS payloads. An application programming interface (API) allows for payload users to gain access to all data processed by TReK and allows payload-specific tools and programs to be built or integrated with TReK. Used in conjunction with other ISS-provided tools, TReK provides the ability to integrate payloads with the operational ground system early in the lifecycle. This reduces the potential for operational problems and provides "cradle-to-grave" end-to-end operations. TReK contains user guides and self-paced tutorials along with training applications to allow the user to become familiar with the system

Asking the readers: audience research into alternative journalism

Alternative forms of journalism are said to challenge the passive role of audience members as receivers and to foster active citizenship among alternative journalists and audiences. Yet the scholarly literature on alternative journalism contains more assertions about than evidence from the audience. Downing has described the audience for alternative media as “the virtually unknown”, prompting him to urge journalism scholars to undertake more audience research to help increase our understanding of this allegedly active and civic-minded public. This exploratory study of the people who regularly read a contemporary example of alternative journalism—an investigative local blog covering one UK city—is intended to contribute towards filling the gap identified by Downing. Audience views are explored by means of questionnaires and focus groups, providing some evidence that individuals are attracted to alternative journalism by their dissatisfaction with mainstream media; that they see alternative media as helping them make sense of the world; and that, to an extent, engaging with such media is both a prompt to, and a reflection of, readers’ democratic engagement as citizens. Recognising the limitations of this small study, the article concludes by reiterating Downing's call for further research

Using Threshold Concepts to generate a new understanding of teaching and learning Biology

Students come to tertiary institutions with misconceptions of key concepts in the disciplines they are studying. Their misconceptions commonly relate to conceptually difficult or troublesome knowledge (Perkins 1999) and can be: incomplete, contradictory, stable and highly resistant to change and remain intact despite repeated instruction at successively higher levels, being perhaps reinforced by teachers and textbooks (Driver 1983; Driver, Guesne and Tiberghien, 1985; Gabel 1994). For sometime, we have known that a range of concepts in Biology are conceptually difficult e.g. biochemical pathways, evolution and genetics (Brown 1995; Ross and Tronson 2007, Taylor 2006, 2008), but whether these are the ‘threshold concepts’ of (Meyer and Land 1995) is a question that needs to be explored further. We propose an alternative perspective where threshold crossing can be envisaged more productively as a cognitive process with students transported across a conceptual chasm or threshold. Misconceptions may then lie with an underlying ‘cognitive threshold’ and not a ‘threshold concept’ (Ross et al 2008). This current ALTC funded collaborative project involves three Australian universities and aims to identify the cognitive processes which underlie difficult Biological concepts; develop intervention strategies to improve students’ framework of conceptual understanding, in one or more related concept areas (that is, to help the students cross a conceptual threshold); test whether students can subsequently transfer this thinking process to aid their understanding of other similarly difficult concepts (that is, to see if they have learnt how to cross unfamiliar thresholds). In this paper we present the preliminary results of a survey which asked biology academics (both nationally and internationally) to identify troublesome biological concepts in their teaching, describe the cognitive process that underlies them which may determine why they are troublesome, and to identify the links they perceive with our nominated cognitive thresholds

Threshold Concepts: Challenging the Way We Think, Teach and Learn in Biology and Science

Meyer and Land (2003, 2005) proposed the notion of ‘threshold concepts’, which are central to the mastery of a specific discipline due to their transformative, irreversible and integrative nature. Using the methodology of Davies and Mangan (2007) we interviewed novice students (58) and expert academic staff (11) from three Australian universities and conducted an international survey of academics (55) to identify differences in novice and expert conceptions. We matched these data with understandings from the ‘misconceptions’ literature to create the ‘biology thresholds matrix’. The matrix demonstrates that threshold concepts in biology are not necessarily the troublesome content, but rather the tacit understandings of the discipline (Taylor, 2006, 2008; Ross & Tronson, 2007, Ross, Taylor, Hughes, Kofod, Whitaker, Lutze-Mann & Tzioumis, 2010). These are often not explicitly taught (Perkins, 2006) yet underpin difficult content areas including: energy and energy transformation, variation, probability and randomness, proportionality and surface area to volume ratio, dynamic equilibrium, linking the subcellular (submicroscopic) with the macroscopic, temporal and spatial scales (Ross et al., 2010), and the formulation and testing of hypotheses (Taylor & Meyer, 2010). These threshold concepts are not hierarchical in nature, but form a web of epistemes which has commonalities with tacit understandings in other science disciplines

qMRI-BIDS: An extension to the brain imaging data structure for quantitative magnetic resonance imaging data

The Brain Imaging Data Structure (BIDS) established community consensus on the organization of data and metadata for several neuroimaging modalities. Traditionally, BIDS had a strong focus on functional magnetic resonance imaging (MRI) datasets and lacked guidance on how to store multimodal structural MRI datasets. Here, we present and describe the BIDS Extension Proposal 001 (BEP001), which adds a range of quantitative MRI (qMRI) applications to the BIDS. In general, the aim of qMRI is to characterize brain microstructure by quantifying the physical MR parameters of the tissue via computational, biophysical models. By proposing this new standard, we envision standardization of qMRI through multicenter dissemination of interoperable datasets. This way, BIDS can act as a catalyst of convergence between qMRI methods development and application-driven neuroimaging studies that can help develop quantitative biomarkers for neural tissue characterization. In conclusion, this BIDS extension offers a common ground for developers to exchange novel imaging data and tools, reducing the entrance barrier for qMRI in the field of neuroimaging