2,748 research outputs found
Integrating Industrial Laser Scanners for Small Vessel Operations
The NOAA Navigation Response Teams (NRTs) perform hydrographic surveys to support nautical charting updates for 175 ports of the United States Marine Transportation System.These include the identification of bathymetric and anthropogenic features that may pose a danger to navigation. In addition, NRTs respond to emergencies, speed the resumption of shipping after storm events, and protect life and property from underwater dangers. The spectrum of dangers occurs from natural features, such as rocks to anthropogenic objects such as piers.Previous work conducted by the NOAA Office of Coast Survey have shown that survey-grade laser scanners can be used to remotely map features that are dangers-to-navigation. However, the justifications to purchase these systems are difficult since one system can be on the order of several hundred thousand dollars. An alternative solution is proposed through the use of economical industrial laser scanners. The capabilities of these systems can vary widely with range and angular resolution and require additional integration (e.g., translation into geographic space and timing considerations) into the network of sensors typical of vessels engaged inhydrographic operations. This paper presents evaluation work to balance cost versus performance using an industrial laser scanner into a hydrographic system. The laser scanner wasevaluated in a laboratory setting at the Joint Hydrographic Center / Center for Coastal and Ocean Mapping (CCOM/JHC), University of New Hampshire (UNH) water tank facilities and aboard the R/V Coastal Surveyor (Portsmouth Harbor, NH). The results of the study include a first-order analysis of Velodyne’s VLP-32E system and its target detection performance on piers, piles, air gaps and overhanging cables
Attempts to detect retrotransposition and de novo deletion of Alus and other dispersed repeats at specific loci in the human genome
Dispersed repeat elements contribute to genome instability by de novo insertion and unequal recombination between repeats. To study the dynamics of these processes, we have developed single DNA molecule approaches to detect de novo insertions at a single locus and Alu-mediated deletions at two different loci in human genomic DNA. Validation experiments showed these approaches could detect insertions and deletions at frequencies below 10(-6) per cell. However, bulk analysis of germline (sperm) and somatic DNA showed no evidence for genuine mutant molecules, placing an upper limit of insertion and deletion rates of 2 x 10(-7) and 3 x 10(-7), respectively, in the individuals tested. Such re-arrangements at these loci therefore occur at a rate lower than that detectable by the most sensitive methods currently available
Preferred reporting items for animal studies in endodontology (PRIASE): a development protocol
The regulated use of animals in endodontic research is often necessary to investigate the biological mechanisms of endodontic diseases and to measure the preclinical efficacy, biocompatibility, toxicology and safety of new treatments, biomaterials, sealers, drugs, disinfectants, irrigants, devices and instruments. Animal testing is most crucial in situations when research on humans is not ethical, practical or has unknown health risks. Currently, there is a wide variability in the quality of manuscripts that report the results of animal studies. Towards the goal of improving the quality of publications, guidelines for preventing disability, pain, and suffering to animals, and enhanced reporting requirements for animal research have been developed. These guidelines are referred to as Animals in Research: Reporting In Vivo Experiments (ARRIVE). Henceforth, causing any form of animal suffering for research purposes is not acceptable and cannot be justified under any circumstances. The present report describes a protocol for the development of welfare and reporting guidelines for animal studies conducted in the specialty of Endodontology: the Preferred Reporting Items for Animal Studies in Endodontology (PRIASE) guidelines. The PRIASE guidelines will be developed by adapting and modifying the ARRIVE guidelines and the Clinical and Laboratory Images in Publication (CLIP) principles. The development of the new PRIASE guidelines will include a five‐step consensus process. An initial draft of the PRIASE guidelines will be developed by a steering committee. Each item in the draft guidelines will then be evaluated by members of a PRIASE Delphi Group (PDG) for its clarity using a dichotomous scale (yes or no) and suitability for its inclusion using a 9‐point Likert scale. The online surveys will continue until each item achieves this standard, and a set of items are agreed for further analysis by a PRIASE Face‐to‐face Consensus Meeting Group (PFCMG). Following the consensus meeting, the steering committee will finalize and confirm the PRIASE guidelines taking into account the responses and comments of the PFCMG. The PRIASE guidelines will be published and disseminated internationally and updated periodically based on feedback from stakeholders
A mathematical modelling study of an athlete's sprint time when towing a weighted sled
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s12283-013-0114-2.This study used a mathematical model to examine the effects of the sled, the running surface, and the athlete on sprint time when towing a weighted sled. Simulations showed that ratio scaling is an appropriate method of normalising the weight of the sled for athletes of different body size. The relationship between sprint time and the weight of the sled was almost linear, as long as the sled was not excessively heavy. The athlete’s sprint time and rate of increase in sprint time were greater on running surfaces with a greater coefficient of friction, and on any given running surface an athlete with a greater power-to-weight ratio had a lower rate of increase in sprint time. The angle of the tow cord did not have a substantial effect on an athlete’s sprint time. This greater understanding should help coaches set the training intensity experienced by an athlete when performing a sled-towing exercise
The rolling problem: overview and challenges
In the present paper we give a historical account -ranging from classical to
modern results- of the problem of rolling two Riemannian manifolds one on the
other, with the restrictions that they cannot instantaneously slip or spin one
with respect to the other. On the way we show how this problem has profited
from the development of intrinsic Riemannian geometry, from geometric control
theory and sub-Riemannian geometry. We also mention how other areas -such as
robotics and interpolation theory- have employed the rolling model.Comment: 20 page
Mathematical evaluation of jumping distance in total hip arthroplasty: Influence of abduction angle, femoral head offset, and head diameter
Background and purpose The jumping distance (JD) is the degree of lateral translation of the femoral head center required before dislocation occurs. The smaller the distance, the higher the theoretical risk of dislocation. The aim of our study was to evaluate this jumping distance and its variation according to the characteristics of the implant, and also the theoretical gain in using large head diameters of above 38 mm
Evidence in cortical folding patterns for prenatal predispositions to hallucinations in schizophrenia.
All perception is a construction of the brain from sensory input. Our first perceptions begin during gestation, making fetal brain development fundamental to how we experience a diverse world. Hallucinations are percepts without origin in physical reality that occur in health and disease. Despite longstanding research on the brain structures supporting hallucinations and on perinatal contributions to the pathophysiology of schizophrenia, what links these two distinct lines of research remains unclear. Sulcal patterns derived from structural magnetic resonance (MR) images can provide a proxy in adulthood for early brain development. We studied two independent datasets of patients with schizophrenia who underwent clinical assessment and 3T MR imaging from the United Kingdom and Shanghai, China (n = 181 combined) and 63 healthy controls from Shanghai. Participants were stratified into those with (n = 79 UK; n = 22 Shanghai) and without (n = 43 UK; n = 37 Shanghai) hallucinations from the PANSS P3 scores for hallucinatory behaviour. We quantified the length, depth, and asymmetry indices of the paracingulate and superior temporal sulci (PCS, STS), which have previously been associated with hallucinations in schizophrenia, and constructed cortical folding covariance matrices organized by large-scale functional networks. In both ethnic groups, we demonstrated a significantly shorter left PCS in patients with hallucinations compared to those without, and to healthy controls. Reduced PCS length and STS depth corresponded to focal deviations in their geometry and to significantly increased covariance within and between areas of the salience and auditory networks. The discovery of neurodevelopmental alterations contributing to hallucinations establishes testable models for these enigmatic, sometimes highly distressing, perceptions and provides mechanistic insight into the pathological consequences of prenatal origins
Socioeconomic position across the lifecourse & allostatic load: data from the West of Scotland Twenty-07 cohort study
Background: We examined how socioeconomic position (SEP) across the lifecourse (three critical periods, social mobility and accumulated over time) is associated with allostatic load (a measure of cumulative physiological burden). Methods. Data are from the West of Scotland Twenty-07 Study, with respondents aged 35 (n = 740), 55 (n = 817) and 75 (n = 483). SEP measures representing childhood, the transition to adulthood and adulthood SEP were used. Allostatic load was produced by summing nine binary biomarker scores (1 = in the highest-risk quartile). Linear regressions were used for each of the lifecourse models; with model fits compared using partial F-tests. Results: For those aged 35 and 55, higher SEP was associated with lower allostatic load (no association in the 75-year-olds). The accumulation model (more time spent with higher SEP) had the best model fit in those aged 35 (b = -0.50, 95%CI = -0.68, -0.32, P = 0.002) and 55 (b = -0.31, 95%CI = -0.49, -0.12, P < 0.001). However, the relative contributions of each life-stage differed, with adulthood SEP less strongly associated with allostatic load. Conclusions: Long-term, accumulated higher SEP has been shown to be associated with lower allostatic load (less physiological burden). However, the transition to adulthood may represent a particularly sensitive period for SEP to impact on allostatic load. © 2014 Robertson et al.; licensee BioMed Central Ltd
Bidirectional lipid droplet velocities are controlled by differential binding strengths of HCV Core DII protein
Host cell lipid droplets (LD) are essential in the hepatitis C virus (HCV) life cycle and are targeted by the viral capsid core protein. Core-coated LDs accumulate in the perinuclear region and facilitate viral particle assembly, but it is unclear how mobility of these LDs is directed by core. Herein we used two-photon fluorescence, differential interference contrast imaging, and coherent anti-Stokes Raman scattering microscopies, to reveal novel core-mediated changes to LD dynamics. Expression of core protein’s lipid binding domain II (DII-core) induced slower LD speeds, but did not affect directionality of movement on microtubules. Modulating the LD binding strength of DII-core further impacted LD mobility, revealing the temporal effects of LD-bound DII-core. These results for DII-core coated LDs support a model for core-mediated LD localization that involves core slowing down the rate of movement of LDs until localization at the perinuclear region is accomplished where LD movement ceases. The guided localization of LDs by HCV core protein not only is essential to the viral life cycle but also poses an interesting target for the development of antiviral strategies against HCV
Femoroacetabular impingement and classification of the cam deformity: the reference interval in normal hips
BACKGROUND AND PURPOSE: Most patients with femoroacetabular impingement (FAI) have a cam deformity, which may be quantified by measuring the alpha angle and anterior offset ratio (AOR). Knowledge of what constitutes a "normal" alpha angle and AOR is limited. We defined the reference intervals of these measurements from normal hips in the general population. PATIENTS AND METHODS: 157 individuals from the general population were reviewed clinically and radiographically. 74 individuals with clinical evidence of hip disease or radiographic evidence of osteoarthritis (OA) were excluded, leaving a study group of 83 individuals (mean age 46 (22-69) years, 44 females) with normal hips. The alpha angles and AORs were measured from cross-table lateral radiographs taken in 15 degrees internal rotation. A validation study consisting of a cadaver study and a measurement reliability study was also performed. RESULTS: The mean alpha angle was 48 degrees in men and 47 degrees in women. The mean AOR was 0.19, the same in men and women. Thus, sexes were combined to derive 95% confidence intervals for the population mean alpha angle (46-49 degrees ) and AOR (0.18-0.20). The 95% reference interval for the alpha angle was 32-62 degrees degrees, and for the AOR it was 0.14-0.24. The validation study confirmed that these measurements were resistant to a reasonable degree of variation in positioning and that the repeatability and reproducibility of the measurements was good. INTERPRETATION: These reference intervals indicate that clinically and radiographically normal hips may have alpha angles and AORs that have previously been considered "abnormal". The thresholds provided by this study will aid classification of individuals involved in longitudinal studies of FAI and OA, and may be of use to the practicing clinician in evaluating the young adult with hip pain
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