1,220 research outputs found
Visual Odometry using Convolutional Neural Networks
Visual odometry is the process of tracking an agent\u27s motion over time using a visual sensor. The visual odometry problem has only been recently solved using traditional, non-machine learning techniques. Despite the success of neural networks at many related problems such as object recognition, feature detection, and optical flow, visual odometry still has not been solved with a deep learning technique. This paper attempts to implement several Convolutional Neural Networks to solve the visual odometry problem and compare slight variations in data preprocessing. The work presented is a step toward reaching a legitimate neural network solution
The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review
PMCID: PMC3408383The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1741-7015/10/75.
This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited
Local Star formation triggered by SN shocks in magnetized diffuse neutral clouds
In this work, considering the impact of a SNR with a neutral magnetized cloud
we derived analytically a set of conditions which are favorable for driving
gravitational instability in the cloud and thus star formation. We have built
diagrams of the SNR radius, versus the cloud density, that constrain a domain
in the parameter space where star formation is allowed. The diagrams are also
tested with fully 3-D MHD simulations involving a SNR and a self-gravitating
cloud and we find that the numerical analysis is consistent with the results
predicted by the diagrams. While the inclusion of a homogeneous magnetic field
approximately perpendicular to the impact velocity of the SNR with an intensity
~1 G results only a small shrinking of the star formation triggering zone
in the diagrams, a larger magnetic field (~10 G) causes a significant
shrinking, as expected. Applications of the diagrams to a few regions of our
own galaxy have revealed that star formation in those sites could have been
triggered by shock waves from SNRs. Finally, we have evaluated the effective
star formation efficiency for this sort of interaction and found that it is
smaller than the observed values in our own Galaxy (sfe ~0.01-0.3). This result
is consistent with previous work in the literature and also suggests that the
mechanism presently investigated, though very powerful to drive structure
formation, supersonic turbulence and eventually, local star formation, does not
seem to be sufficient to drive global star formation in normal star forming
galaxies, not even when the magnetic field in the neutral clouds is neglected.
(abridged)Comment: 19 pages, 13 figures, accepted for pubblication in MNRA
Genetic Study in a Case of Birt-Hogg-Dubé Syndrome
Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominantly inherited disorder characterized by multiple trichodiscomas, fibrofolliculomas, and acrocordons. There is also an increased risk of developing renal neoplasms and lung cysts/spontaneous pneumothorax. We present a 43-year-old man with multiple, 2~4 mm sized, dome-shaped, and skin-colored papules on his cheek and neck. On the basis of clinical finding and histopathologic examination on the cheek lesion, it was diagnosed as multiple trichodiscomas. Subsequently, molecular analysis revealed a mutation in the folliculin gene. We report a rare case of BHDS with a proved gene mutation
The Hong-Ou-Mandel effect with atoms
Controlling light at the level of individual photons has led to advances in
fields ranging from quantum information and precision sensing to fundamental
tests of quantum mechanics. A central development that followed the advent of
single photon sources was the observation of the Hong-Ou- Mandel (HOM) effect,
a novel two-photon path interference phenomenon experienced by
indistinguishable photons. The effect is now a central technique in the field
of quantum optics, harnessed for a variety of applications such as diagnosing
single photon sources and creating probabilistic entanglement in linear quantum
computing. Recently, several distinct experiments using atomic sources have
realized the requisite control to observe and exploit Hong-Ou-Mandel
interference of atoms. This article provides a summary of this phenomenon and
discusses some of its implications for atomic systems. Transitioning from the
domain of photons to atoms opens new perspectives on fundamental concepts, such
as the classification of entanglement of identical particles. It aids in the
design of novel probes of quantities such as entanglement entropy by combining
well established tools of AMO physics - unity single-atom detection, tunable
interactions, and scalability - with the Hong-Ou-Mandel interference.
Furthermore, it is now possible for established protocols in the photon
community, such as measurement-induced entanglement, to be employed in atomic
experiments that possess deterministic single-particle production and
detection. Hence, the realization of the HOM effect with atoms represents a
productive union of central ideas in quantum control of atoms and photons.Comment: 19 pages, 7 figure
Implantation of canine umbilical cord blood-derived mesenchymal stem cells mixed with beta-tricalcium phosphate enhances osteogenesis in bone defect model dogs
This study was performed to evaluate the osteogenic effect of allogenic canine umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) mixed with beta-tricalcium phosphate (β-TCP) in orthotopic implantation. Seven hundred milligrams of β-TCP mixed with 1 × 106 UCB-MSCs diluted with 0.5 ml of saline (group CM) and mixed with the same volume of saline as control (group C) were implanted into a 1.5 cm diaphyseal defect and wrapped with PLGC membrane in the radius of Beagle dogs. Radiographs of the antebrachium were made after surgery. The implants were harvested 12 weeks after implantation and specimens were stained with H&E, toluidine blue and Villanueva-Goldner stains for histological examination and histomorphometric analysis of new bone formation. Additionally, UCB-MSCs were applied to a dog with non-union fracture. Radiographically, continuity between implant and host bone was evident at only one of six interfaces in group C by 12 weeks, but in three of six interfaces in group CM. Radiolucency was found only near the bone end in group C at 12 weeks after implantation, but in the entire graft in group CM. Histologically, bone formation was observed around β-TCP in longitudinal sections of implant in both groups. Histomorphometric analysis revealed significantly increased new bone formation in group CM at 12 weeks after implantation (p < 0.05). When applied to the non-union fracture, fracture healing was identified by 6 weeks after injection of UCB-MSCs. The present study indicates that a mixture of UCB-MSCs and β-TCP is a promising osteogenic material for repairing bone defects
Physiotherapy for Parkinson's disease: a comparison of techniques (Review)
Background: Despite medical therapies and surgical interventions for Parkinson's disease (PD), patients develop progressive disability. The role of physiotherapy is to maximise functional ability and minimise secondary complications through movement rehabilitation within a context of education and support for the whole person. The overall aim is to optimise independence, safety and wellbeing, thereby enhancing quality of life. Trials have shown that physiotherapy has short-term benefits in PD. However, which physiotherapy intervention is most effective remains unclear. Objectives: To assess the effectiveness of one physiotherapy intervention compared with a second approach in patients with PD. Search methods: Relevant trials were identified by electronic searches of numerous literature databases (for example MEDLINE, EMBASE) and trial registers, plus handsearching of major journals, abstract books, conference proceedings and reference lists of retrieved publications. The literature search included trials published up to the end of January 2012. Selection criteria: Randomised controlled trials of one physiotherapy intervention versus another physiotherapy intervention in patients with PD. Data collection and analysis: Data were abstracted independently from each paper by two authors. Trials were classified into the following intervention comparisons: general physiotherapy, exercise, treadmill training, cueing, dance and martial arts. Main results: A total of 43 trials were identified with 1673 participants. All trials used small patient numbers (average trial size of 39 participants); the methods of randomisation and concealment of allocation were poor or not stated in most trials. Blinded assessors were used in just over half of the trials and only 10 stated that they used intention-to-treat analysis.A wide variety of validated and customised outcome measures were used to assess the effectiveness of physiotherapy interventions. The most frequently reported physiotherapy outcomes were gait speed and timed up and go, in 19 and 15 trials respectively. Only five of the 43 trials reported data on falls (12%). The motor subscales of the Unified Parkinson?s Disease Rating Scale and Parkinson?s Disease Questionnaire-39 were the most commonly reported clinician-rated disability and patient-rated quality of life outcome measures, used in 22 and 13 trials respectively. The content and delivery of the physiotherapy interventions varied widely in the trials included within this review, so no quantitative meta-analysis could be performed. Authors' conclusions: Considering the small number of participants examined, the methodological flaws in many of the studies, the possibility of publication bias, and the variety of interventions, formal comparison of the different physiotherapy techniques could not be performed. There is insufficient evidence to support or refute the effectiveness of one physiotherapy intervention over another in PD.This review shows that a wide range of physiotherapy interventions to treat PD have been tested . There is a need for more specific trials with improved treatment strategies to underpin the most appropriate choice of physiotherapy intervention and the outcomes measured
Physiotherapy versus placebo or no intervention in Parkinson's disease
Background: Despite medical therapies and surgical interventions for Parkinson's disease (PD), patients develop progressive disability. Physiotherapy aims to maximise functional ability and minimise secondary complications through movement rehabilitation within a context of education and support for the whole person. The overall aim is to optimise independence, safety, and well-being, thereby enhancing quality of life. Objectives: To assess the effectiveness of physiotherapy intervention compared with no intervention in patients with PD. Search methods: We identified relevant trials by conducting electronic searches of numerous literature databases (e.g. MEDLINE, EMBASE) and trial registers, and by handsearching major journals, abstract books, conference proceedings, and reference lists of retrieved publications. The literature search included trials published up to the end of January 2012. Selection criteria: Randomised controlled trials of physiotherapy intervention versus no physiotherapy intervention in patients with PD. Data collection and analysis: Two review authors independently extracted data from each article. We used standard meta-analysis methods to assess the effectiveness of physiotherapy intervention compared with no physiotherapy intervention. Trials were classified into the following intervention comparisons: general physiotherapy, exercise, treadmill training, cueing, dance, and martial arts. We used tests for heterogeneity to assess for differences in treatment effect across these different physiotherapy interventions. Main results: We identified 39 trials with 1827 participants. We considered the trials to be at a mixed risk of bias as the result of unreported allocation concealment and probable detection bias. Compared with no intervention, physiotherapy significantly improved the gait outcomes of speed (mean difference 0.04 m/s, 95% confidence interval (CI) 0.02 to 0.06, P = 0.0002); two- or six-minute walk test (13.37 m, 95% CI 0.55 to 26.20, P = 0.04) and Freezing of Gait questionnaire (-1.41, 95% CI -2.63 to -0.19, P = 0.02); functional mobility and balance outcomes of Timed Up & Go test (-0.63 s, 95% CI -1.05 to -0.21, P = 0.003), Functional Reach Test (2.16 cm, 95% CI 0.89 to 3.43, P = 0.0008), and Berg Balance Scale (3.71 points, 95% CI 2.30 to 5.11, P < 0.00001); and clinician-rated disability using the Unified Parkinson’s Disease Rating Scale (UPDRS) (total -6.15 points, 95% CI-8.57 to -3.73, P < 0.00001; activities of daily living: -1.36, 95% CI -2.41 to -0.30, P = 0.01; and motor: -5.01, 95% CI -6.30 to -3.72, P < 0.00001). No difference between arms was noted in falls (Falls Efficacy Scale: -1.91 points, 95% CI -4.76 to 0.94, P = 0.19) or patient-rated quality of life (PDQ-39 Summary Index: -0.38 points, 95% CI -2.58 to 1.81, P = 0.73). One study reported that adverse events were rare; no other studies reported data on this outcome. Indirect comparisons of the different physiotherapy interventions revealed no evidence that the treatment effect differed across physiotherapy interventions for any of the outcomes assessed. Authors' conclusions: Benefit for physiotherapy was found in most outcomes over the short term (i.e. < 3 months) but was significant only for speed, two- or six-minute walk test, Freezing of Gait questionnaire, Timed Up & Go, Functional Reach Test, Berg Balance Scale, and clinician-rated UPDRS. Most of the observed differences between treatments were small. However, for some outcomes (e.g. speed, Berg Balance Scale, UPDRS), the differences observed were at, or approaching, what are considered minimal clinically important changes. These benefits should be interpreted with caution because the quality of most of the included trials was not high. Variation in measurements of outcome between studies meant that our analyses include a small proportion of the participants recruited. This review illustrates that a wide range of approaches are employed by physiotherapists to treat patients with PD. However, no evidence of differences in treatment effect was noted between the different types of physiotherapy interventions being used, although this was based on indirect comparisons. A consensus menu of 'best practice' physiotherapy is needed, as are large, well-designed randomised controlled trials undertaken to demonstrate the longer-term efficacy and cost-effectiveness of 'best practice' physiotherapy in PD
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