Range Estimation Algorithm Comparison in 3-D Flash LADAR Data

Range estimation algorithms have been applied to Laser Detection and Ranging (LADAR) data to test for accuracy and precision. Data was acquired from Matlab® simulations and an experiment using the Advanced Scientific Concepts 3-D flash LADAR camera. Simulated LADAR data was based on a Gaussian pulse shape model with Poisson noise added. Simulations were performed to test range estimation algorithm performance with respect to waveform position within the range gate. The effectiveness of each algorithm is presented in terms of its average root mean square error and standard deviation in 1000 trials. The measured data experiment examined the effectiveness of an algorithm\u27s ability to determine a range difference between 2 flat surfaces. The algorithms compared for analysis include a peak, maximum likelihood, and matched filter estimator. Various interpolation strategies were implemented in the peak estimator. The matched filter was implemented in the time and frequency domains. A normalized version of the matched filter was also developed and applied to the LADAR data. Three different methods based on averaging were developed to calibrate the pulse width of the reference waveform used in the matched filters and maximum likelihood algorithms. Simulation results show that a matched filter produces a bias when waveforms are off center, but normalizing waveforms before computing the cross correlation can reduce the average bias from 0.335 meters to 0.124 meters. The maximum likelihood algorithm also produces a bias in shifted waveforms, while the peak estimator maintains a nearly constant level of bias in its measurements due to the effect of shot noise on waveforms. In the measured data sets, normalization did not reduce the bias in measurements because it increased the algorithm\u27s sensitivity to errors in the reference waveform model. The maximum likelihood algorithm\u27s sensitivity to errors in modeling were revealed due to its poor performance in the measured data

Three Meta-Phases of a Project

This paper proposes three high-level project meta-phases to enhance the understanding of how projects are created and their long-term impacts after completion. It extends the traditional view of the projects to include activities which occur before the initiation of the project and after the closeout phase. These meta-phases are project conception, project execution, and deliverable use. These meta-phases are described and explained in terms of their usefulness for project management research

TOWARDS A CONSENSUS DEFINITION OF FULL-STACK DEVELOPMENT

Full-stack development is a new concept systems development. Full-stack developers have broad knowledge across all aspects of a given technology stack. They have the ability to rapidly transform a concept into a functional solution. Their big-picture visibility allows them to anticipate problems early-on and steer projects around them. Many organizations actively recruit full-stack developers. Many programmers are styling themselves as full-stack developers. However, there is some disagreement regarding the meaning of full-stack development. The disagreement primarily concerns the developer’s expected breadth and depth of stack knowledge. The purpose of this research is to develop a consensus definition of full-stack development. A content analysis of articles which discuss full-stack development is performed. The results are synthesized to form a conceptual definition which clarifies the role of full-stack developers. This definition alleviates confusion and provides clarity. The results have implications for research and practice

Variation in the flowering time orthologs BrFLC and BrSOC1 in a natural population of Brassica rapa.

Understanding the genetic basis of natural phenotypic variation is of great importance, particularly since selection can act on this variation to cause evolution. We examined expression and allelic variation in candidate flowering time loci in Brassica rapa plants derived from a natural population and showing a broad range in the timing of first flowering. The loci of interest were orthologs of the Arabidopsis genes FLC and SOC1 (BrFLC and BrSOC1, respectively), which in Arabidopsis play a central role in the flowering time regulatory network, with FLC repressing and SOC1 promoting flowering. In B. rapa, there are four copies of FLC and three of SOC1. Plants were grown in controlled conditions in the lab. Comparisons were made between plants that flowered the earliest and latest, with the difference in average flowering time between these groups ∼30 days. As expected, we found that total expression of BrSOC1 paralogs was significantly greater in early than in late flowering plants. Paralog-specific primers showed that expression was greater in early flowering plants in the BrSOC1 paralogs Br004928, Br00393 and Br009324, although the difference was not significant in Br009324. Thus expression of at least 2 of the 3 BrSOC1 orthologs is consistent with their predicted role in flowering time in this natural population. Sequences of the promoter regions of the BrSOC1 orthologs were variable, but there was no association between allelic variation at these loci and flowering time variation. For the BrFLC orthologs, expression varied over time, but did not differ between the early and late flowering plants. The coding regions, promoter regions and introns of these genes were generally invariant. Thus the BrFLC orthologs do not appear to influence flowering time in this population. Overall, the results suggest that even for a trait like flowering time that is controlled by a very well described genetic regulatory network, understanding the underlying genetic basis of natural variation in such a quantitative trait is challenging

Using Experts for Improving Project Cybersecurity Risk Scenarios

This study implemented an expert panel to assess the content validity of hypothetical scenarios to be used in a survey of cybersecurity risk across project meta-phases. Six out of 10 experts solicited completed the expert panel exercise. Results indicate that although experts often disagreed with each other and on the expected mapping of scenario to project meta-phase, the experts generally found risk present in the scenarios and across all three project meta-phases, as hypothesized

Intraocular Lens Tilt Due to Optic-Haptic Junction Distortion Following Intrascleral Haptic Fixation With the Yamane Technique

Purpose: To report two patients with a complication of Yamane intrascleral haptic fixation surgery (ISHF) with the Zeiss CT Lucia 602 lens: severely tilted intraocular lens (IOL) leading to significantly decreased vision in the early post-operative period. Observations: We report two patients presenting with severely tilted IOL implants one day and one month following Yamane ISHF. The first patient is a monocular 81-year-old woman referred for treatment of cornea edema. Initial surgery involved replacement of an anterior chamber lens with a CT Lucia 602 posterior chamber lens using Yamane technique and Descemet\u27s stripping endothelial keratoplasty. The patient returned at one month follow-up with poor vision and IOL tilt observable at the slit lamp through a peripheral iridectomy site. Explanation of the Zeiss lens revealed haptic distortion at the optic-haptic insertion point such that each haptic was about 45° off axis to the plane of the optic in approximately equal and opposite directions. The second patient, a 75-year-old woman, was referred with a completely dislocated lens-bag complex in the right eye. The initial operative treatment for this patient included pars plana vitrectomy, retrieval and removal of the dislocated lens-bag complex, and placement of a Zeiss 602 lens via Yamane ISHF technique. On the first postoperative day, the patient was count fingers in the right eye with an intraocular pressure of 5 mm Hg and obvious IOL tilt on slit lamp examination. Explanation of the lens revealed severely distorted haptics relative to the optic by more than a 60-degree angle on both sides. In both cases, initial surgery was performed with an IOL inspected prior to implantation and found to have normal appearing haptics. At the end of each case, there was adequate centration and no tilt of the IOL. Management in both patients included removal of the defective lens and placement of a new, same power CT Lucia 602 lens via the Yamane technique. Visual acuity improved from CF to 20/30 best corrected after reoperation in both cases. Conclusions and importance: In summary, we describe a complication of Yamane ISHF with the CT Lucia 602 lens in which there is lens tilting associated with distortion at the optic-haptic fastening zone in the early postoperative period. In the event of a titled lens following Yamane ISHF, awareness of this complication may help surgeons consider lens replacement, as the haptics may be permanently distorted or damaged

A Molecular Line Survey around Orion at Low Frequencies with the MWA

The low-frequency sky may reveal some of the secrets yet to be discovered. Until recently, molecules had never been detected within interstellar clouds at frequencies below 700 MHz. Following the pilot survey toward the Galactic center at 103-133 MHz with the Murchison Widefield Array, we surveyed 400 deg2centered on the Orion KL nebula from 99 to 170 MHz. Orion is a nearby region of active star formation and known to be a chemically rich environment. In this paper, we present tentative detections of nitric oxide and its isotopologues, singularly deuterated formic acid, molecular oxygen, and several unidentified transitions. The three identified molecules are particularly interesting, as laboratory experiments have suggested that these molecules are precursors to the formation of amines

Mass fluxes and isofluxes of methane (CH4) at a New Hampshire fen measured by a continuous wave quantum cascade laser spectrometer

We have developed a mid‐infrared continuous‐wave quantum cascade laser direct‐absorption spectrometer (QCLS) capable of high frequency (≥1 Hz) measurements of 12CH4 and 13CH4 isotopologues of methane (CH4) with in situ 1‐s RMS image precision of 1.5 ‰ and Allan‐minimum precision of 0.2 ‰. We deployed this QCLS in a well‐studied New Hampshire fen to compare measurements of CH4 isoflux by eddy covariance (EC) to Keeling regressions of data from automated flux chamber sampling. Mean CH4 fluxes of 6.5 ± 0.7 mg CH4 m−2 hr−1 over two days of EC sampling in July, 2009 were indistinguishable from mean autochamber CH4 fluxes (6.6 ± 0.8 mgCH4 m−2 hr−1) over the same period. Mean image composition of emitted CH4 calculated using EC isoflux methods was −71 ± 8 ‰ (95% C.I.) while Keeling regressions of 332 chamber closing events over 8 days yielded a corresponding value of −64.5 ± 0.8 ‰. Ebullitive fluxes, representing ∼10% of total CH4 fluxes at this site, were on average 1.2 ‰ enriched in 13C compared to diffusive fluxes. CH4 isoflux time series have the potential to improve process‐based understanding of methanogenesis, fully characterize source isotopic distributions, and serve as additional constraints for both regional and global CH4 modeling analysis

Galaxy Zoo: Disentangling the Environmental Dependence of Morphology and Colour

We analyze the environmental dependence of galaxy morphology and colour with two-point clustering statistics, using data from the Galaxy Zoo, the largest sample of visually classified morphologies yet compiled, extracted from the Sloan Digital Sky Survey. We present two-point correlation functions of spiral and early-type galaxies, and we quantify the correlation between morphology and environment with marked correlation functions. These yield clear and precise environmental trends across a wide range of scales, analogous to similar measurements with galaxy colours, indicating that the Galaxy Zoo classifications themselves are very precise. We measure morphology marked correlation functions at fixed colour and find that they are relatively weak, with the only residual correlation being that of red galaxies at small scales, indicating a morphology gradient within haloes for red galaxies. At fixed morphology, we find that the environmental dependence of colour remains strong, and these correlations remain for fixed morphology \textit{and} luminosity. An implication of this is that much of the morphology--density relation is due to the relation between colour and density. Our results also have implications for galaxy evolution: the morphological transformation of galaxies is usually accompanied by a colour transformation, but not necessarily vice versa. A spiral galaxy may move onto the red sequence of the colour-magnitude diagram without quickly becoming an early-type. We analyze the significant population of red spiral galaxies, and present evidence that they tend to be located in moderately dense environments and are often satellite galaxies in the outskirts of haloes. Finally, we combine our results to argue that central and satellite galaxies tend to follow different evolutionary paths.Comment: 19 pages, 18 figures. Accepted for publication in MNRA

Management of blunt extracranial traumatic cerebrovascular injury: a multidisciplinary survey of current practice

<p>Abstract</p> <p>Background</p> <p>Extracranial traumatic cerebrovascular injury (TCVI) is present in 1-3% of all blunt force trauma patients. Although options for the management of patients with these lesions include anticoagulation, antiplatelet agents, and endovascular treatment, the optimal management strategy for patients with these lesions is not yet established.</p> <p>Objective</p> <p>Multidisciplinary survey of clinicians about current management of TCVI.</p> <p>Methods</p> <p>A six-item multiple-choice survey was sent by electronic mail to a total of 11,784 neurosurgeons, trauma surgeons, stroke neurologists, and interventional radiologists. The survey included questions about their choice of imaging, medical management, and the use of endovascular techniques. Survey responses were analyzed according to stated specialty.</p> <p>Results</p> <p>Seven hundred eighty-five (6.7%) responses were received. Overall, a total of 325 (42.8%) respondents favored anticoagulation (heparin and/or warfarin), 247 (32.5%) favored antiplatelet drugs, 130 (17.1%) preferred both anticoagulation and antiplatelet drugs, and 57 (7.5%) preferred stenting and/or embolization. Anticoagulation was the most commonly preferred treatment among vascular surgeons (56.9%), neurologists (50.2%) and neurosurgeons (40.7%), whereas antiplatelet agents were the most common preferred treatment among trauma surgeons (41.5%). Overall, 158 (20.7%) of respondents recommended treatment of asymptomatic dissections and traumatic aneurysms, 211 (27.7%) did not recommend it, and 39.4% recommended endovascular treatment only if there is worsening of the lesion on follow-up imaging.</p> <p>Conclusions</p> <p>These data demonstrate the wide variability of physicians' management of traumatic cerebrovascular injury, both on an individual basis, and between specialties. These findings underscore the need for multicenter, randomized trials in this field.</p