SciCombinator

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Concept: The Point

145

Scan matching, an approach to recover the relative position and orientation of two laser scans, is a very important technique for indoor positioning and indoor modeling. The iterative closest point (ICP) algorithm and its variants are the most well-known techniques for such a problem. However, ICP algorithms rely highly on the initial guess of the relative transformation, which will reduce its power for practical applications. In this paper, an initial-free 2D laser scan matching method based on point and line features is proposed. We carefully design a framework for the detection of point and line feature correspondences. First, distinct feature points are detected based on an extended 1D SIFT, and line features are extracted via a modified Split-and-Merge algorithm. In this stage, we also give an effective strategy for discarding unreliable features. The point and line features are then described by a distance histogram; the pairs achieving best matching scores are accepted as potential correct correspondences. The histogram cluster technique is adapted to filter outliers and provide an accurate initial value of the rigid transformation. We also proposed a new relative pose estimation method that is robust to outliers. We use the lq-norm (0 < q < 1) metric in this approach, in contrast to classic optimization methods whose cost function is based on the l₂-norm of residuals. Extensive experiments on real data demonstrate that the proposed method is almost as accurate as ICPs and is initial free. We also show that our scan matching method can be integrated into a simultaneous localization and mapping (SLAM) system for indoor mapping.

Concepts: Algorithm, Euclidean geometry, Features new to Windows Vista, Point, Positioning, The Point, Simultaneous localization and mapping, Iterative Closest Point

83

The past few months have witnessed the most intense and prolonged criticism of England’s National Health Service (NHS) in its 65-year history. Some critics have suggested that the NHS faces a crisis that can be resolved only by altering the fundamental principle on which it was founded - provision of funding from general taxation, with care being free at the point of use. Although the criticism was sparked by a February report on an inquiry into shortcomings at one hospital,(1) the problems originated in 2010, when two profound forces were unleashed on the NHS: public-sector financial austerity and administrative reorganization. . . .

Concepts: Health care, National Health Service, Finance, 1999 albums, The Point

82

The role and value of theory in improvement work in healthcare has been seriously underrecognised. We join others in proposing that more informed use of theory can strengthen improvement programmes and facilitate the evaluation of their effectiveness. Many professionals, including improvement practitioners, are unfortunately mystified-and alienated-by theory, which discourages them from using it in their work. In an effort to demystify theory we make the point in this paper that, far from being discretionary or superfluous, theory (‘reason-giving’), both informal and formal, is intimately woven into virtually all human endeavour. We explore the special characteristics of grand, mid-range and programme theory; consider the consequences of misusing theory or failing to use it; review the process of developing and applying programme theory; examine some emerging criteria of ‘good’ theory; and emphasise the value, as well as the challenge, of combining informal experience-based theory with formal, publicly developed theory. We conclude that although informal theory is always at work in improvement, practitioners are often not aware of it or do not make it explicit. The germane issue for improvement practitioners, therefore, is not whether they use theory but whether they make explicit the particular theory or theories, informal and formal, they actually use.

Concepts: Computer program, Theory, Program, Theorem, Formal, The Point

25

The ability to do online searches for health information has led to concerns that patients find the results confusing and that they often lead to expectations for treatments that have little supportive evidence. At the same time, the science of summarizing research evidence has advanced to the point where it is increasingly possible to quantify treatment tradeoffs and to describe the balance between harms and benefits for individual patients.

Concepts: Health care, Illness, The Point

14

There is a global trend towards the use of ad hoc participation processes that seek to engage grassroots stakeholders in decisions related to municipal infrastructure, land use and services. We present the results of a scholarly literature review examining 14 articles detailing specific cases of these processes to contribute to the discussion regarding their utility in advancing health equity. We explore hallmarks of compromised processes, potential harms to grassroots stakeholders, and potential mitigating factors. We conclude that participation processes often cut off participation following the planning phase at the point of implementation, limiting convener accountability to grassroots stakeholders, and, further, that where participation processes yield gains, these are often due to independent grassroots action. Given the emphasis on participation in health equity discourse, this study seeks to provide a real world exploration of the pitfalls and potential harms of participation processes that is relevant to health equity theory and practice.

Concepts: Ad hoc, Explorer, Infrastructure, Equity theory, The Point, Mitigating factor

8

The lack of a marker of epileptogenesis is an unmet medical need, not only from the clinical perspective but also from the point of view of the pre-clinical research. Indeed, the lack of this kind of marker affects the investigations on the mechanisms of epileptogenesis as well as the development of novel therapeutic approaches aimed to prevent or to mitigate the severity of the incoming epilepsy in humans. In this work, we provide evidence that in an experimental model of epileptogenesis that mimics the alteration of the blood-brain barrier permeability, a key-mechanism that contributes to the development of epilepsy in humans and in animals, the prolonged occurrence in the electrocorticograms (ECoG) of high rates of a nonlinear dynamical regimes known as intermittency univocally characterizes the population of experimental animals which develop epilepsy, hence it can be considered as the first biophysical marker of epileptogenesis.

Concepts: Medicine, Biology, Model organism, Neurology, Epilepsy, Seizure, Electrocorticography, The Point

7

Deaths from trauma occurring in the prehospital phase of care are typically excluded from analysis in trauma registries. A direct historical comparison with Hussain and Redmond’s study on preventable prehospital trauma deaths has shown that, two decades on, the number of potentially preventable deaths remains high. Using updated methodology, we aimed to determine the current nature, injury severity and survivability of traumatic prehospital deaths and to ascertain the presence of bystanders and their role following the point of injury including the frequency of first-aid delivery.

Concepts: Cardiopulmonary resuscitation, Psychological trauma, Injury, Wound, The Current, Physical trauma, Emergency medicine, The Point

5

Super-resolution microscopy typically achieves high spatial resolution, but the temporal resolution remains low. We report super temporal-resolved microscopy (STReM) to improve the temporal resolution of 2D super-resolution microscopy by a factor of 20 compared to that of the traditional camera-limited frame rate. This is achieved by rotating a phase mask in the Fourier plane during data acquisition and then recovering the temporal information by fitting the point spread function (PSF) orientations. The feasibility of this technique is verified with both simulated and experimental 2D adsorption/desorption and 2D emitter transport. When STReM is applied to measure protein adsorption at a glass surface, previously unseen dynamics are revealed.

Concepts: Function, Optics, Microscopy, The Point, Frame rate, Point spread function, Spread betting, Astronomical seeing

5

Electronic health registries - eRegistries - can systematically collect relevant information at the point of care for reproductive, maternal, newborn and child health (RMNCH). However, a suite of process and outcome indicators is needed for RMNCH to monitor care and to ensure comparability between settings. Here we report on the assessment of current global indicators and the development of a suite of indicators for the WHO Essential Interventions for use at various levels of health care systems nationally and globally.

Concepts: Health care, Health economics, Medicine, Healthcare, Globalization, The Point

5

Dispersal comprises three broad stages - departure from the natal or breeding locations, subsequent travel, and settlement. These stages are difficult to measure, and vary considerably between sexes, age classes, individuals and geographically. We used tracking data from 24 golden eagles, fitted with long-lived GPS satellite transmitters as nestlings, which we followed during their first year. We estimated the timing of emigration from natal sites using ten previously published methods. We propose and evaluate two new methods. The first of these uses published ranging distances of parents as a measure of the natal home range, with the requirement that juveniles must exceed it for a minimum of 10 days (a literature-based measure of the maximum time that a juvenile can survive without food from its parents). The second method uses the biggest difference in the proportion of locations inside and outside of the natal home range smoothed over a 30 day period to assign the point of emigration. We used the latter as the standard against which we compared the ten published methods.

Concepts: Population, Ireland, Maxima and minima, Global Positioning System, The Point, Eagle, Golden Eagle, Eagles