Generalized Convolutional Neural Networks for Point Cloud Data

The introduction of cheap RGB-D cameras, stereo cameras, and LIDAR devices has given the computer vision community 3D information that conventional RGB cameras cannot provide. This data is often stored as a point cloud. In this paper, we present a novel method to apply the concept of convolutional neural networks to this type of data. By creating a mapping of nearest neighbors in a dataset, and individually applying weights to spatial relationships between points, we achieve an architecture that works directly with point clouds, but closely resembles a convolutional neural net in both design and behavior. Such a method bypasses the need for extensive feature engineering, while proving to be computationally efficient and requiring few parameters

Multimode analysis of non-classical correlations in double well Bose-Einstein condensates

The observation of non-classical correlations arising in interacting two to size weakly coupled Bose-Einstein condensates was recently reported by Esteve et al. [Nature 455, 1216 (2008)]. In order to observe fluctuations below the standard quantum limit, they utilized adiabatic passage to reduce the thermal noise to below that of thermal equilibrium at the minimum realizable temperature. We present a theoretical analysis that takes into account the spatial degrees of freedom of the system, allowing us to calculate the expected correlations at finite temperature in the system, and to verify the hypothesis of adiabatic passage by comparing the dynamics to the idealized model.Comment: 12 pages, 7 figure

Watching the hands of the Arabidopsis biological clock

Oligonucleotide and cDNA microarrays have been used to analyse the mRNA levels of 8,000 genes in Arabidopsis thaliana throughout the day/night cycle. Genes involved in signal transduction and in various metabolic pathways were found to be coordinately regulated by circadian rhythms and/or by light

Assessment of Coating Performance on Waterwalls and Superheaters in a Pulverised Fuel-Fired Power Station

Protective coatings offer one route to increase the lives of heat exchangers in pulverised fuel power plants. A range of candidate coatings have been exposed on the waterwall and superheaters of a 500 MWe UK power station unit for periods of up to ~4 years (24,880 operating hours), during which time this unit was fired on a mixture of UK and world-traded coals. Both nickel- and iron-based candidate coatings were included, applied using high velocity oxy-fuel or arc-wire process; a selection of these also had a surface sealant applied to investigate its effectiveness. Dimensional metrology was used to evaluate coating performances, with SEM/EDX examinations used to investigate the various degradation mechanisms found. Both the waterwall and superheater environments generated their characteristic corrosion damage morphologies which depended on the radial positions around the tube. Coating performances were found to depend on the initial coating quality rather than composition, and were not improved by the use of a sealant

Neutron shielding and activation of the MASTU device and surrounds

A significant functional upgrade is planned for the Mega Ampere Spherical Tokamak (MAST) device, located at Culham in the UK, including the implementation of a notably greater neutral beam injection power. This upgrade will cause the emission of a substantially increased intensity of neutron radiation for a substantially increased amount of time upon operation of the device. Existing shielding and activation precautions are shown to prove insufficient in some regards, and recommendations for improvements are made, including the following areas: shielding doors to MAST shielded facility enclosure (known as "the blockhouse"); north access tunnel; blockhouse roof; west cabling duct. In addition, some specific neutronic dose rate questions are addressed and answered; those discussed here relate to shielding penetrations and dose rate reflected from the air above the device ("skyshine").Comment: 5 pages, 5 figure

Multi-epoch infrared photometry of the star forming region G173.58+2.45

We present a multi-epoch infrared photometric study of the intermediate-mass star forming region G173.58+2.45. Photometric observations are obtained using the near-infrared $JHKL'M'$ filters and narrow-band filters centered at the wavelengths of H$_2$ (1-0) S(1) (2.122 $\mu$m) and [FeII] (1.644 $\mu$m) lines. The H$_2$ image shows molecular emission from shocked gas, implying the presence of multiple star formation and associated outflow activity. We see evidence for several collimated outflows. The most extended jet is at least 0.25 pc in length and has a collimation factor of $\sim$ 10, which may be associated with a binary system within the central cluster, resolved for the first time here. This outflow is found to be episodic; probably occurring or getting enhanced during the periastron passage of the binary. We also find that the variable star in the vicinity of the outflow source, which was known as a FU Ori type star, is probably not a FU Ori object. However, it does drive a spectacular outflow and the variability is likely to be related to accretion, when large clouds of gas and dust spiral in towards the central source. Many other convincing accretion-outflow systems and YSO candidates are discovered in the field.Comment: 15 pages, 9 figures, accepted for publication in MNRA

The Impact of Visual Impairments on Mobility Performance in Community-Dwelling Older Adults

Background and Purpose: Falls are a major concern for elderly adults and can have a significant impact on overall health and well-being. Declines in vision with aging may be related to the development of fear of falling (FOF) and impaired mobility. It is possible that impaired vision due to common eye diseases can increase the FOF avoidance behavior and affect mobility function in this population. The purpose of this study was to investigate the relation among visual impairment, mobility performance, and FOF avoidance behavior in older adults. Methods: Inclusion criteria for eligible participants were: 50 years of age and older, able to walk 50 m without assistance, and able to understand simple instructions related to the assessments. A total of 455 participants from local community adult activity centers (males=152, females=303; age=73.1±7.7 years, range=51-97 years) participated. Physical mobility was assessed using an instrumented Timed Up-and-Go test. Visual acuity (VA) was tested using a standard Snellen chart. Avoidance behavior was assessed using the Fear of Falling Avoidance Behavior Questionnaire (FFABQ). Participants’ general health and presence of eye diseases (age-related macular degeneration, cataracts, and glaucoma) was assessed using a survey of medical history. A two-way ANOVA was used to investigate effect of VA and avoidance behavior on TUG performance. An additional two-way ANOVA test was used to investigate the effect of self-reported eye disease and avoidance behavior on TUG performance. Results and Discussion: There was a statistically significant difference between avoiders and non avoiders’ TUG score (avoiders=12.45±5.85 sec, non-avoiders 8.29±3.48, p\u3c0.001). The VA has no significant effect on TUG time (no impairment= 8.69 ± 3.49 sec, mild impairment= 9.42 ± 5.05 sec, moderate impairment= 8.11 ± 2.08 sec, severe impairment= 9.45 ± 2.68 sec, p=0.791). There is no significant VA group by avoider group interaction (p=0.66). There was also a statistically significant difference in TUG scores between participants with and without eye disease (eye disease=9.37±5.08, no eye disease=8.29±2.80, p=0.004). There is no significant eye disease by avoider group interaction (p=0.144). iv Conclusion: The results of this study indicated that the presence of one or more self-reported eye diseases and higher FOF avoidance behavior were both associated with decreased mobility. Contrary to the initial hypothesis of the present study, there was no relation between VA and mobility, nor VA and FOF avoidance behavior. It is important for clinicians to inquire about the presence of eye diseases and administer the FFABQ to older adults in order to identify risk factors related to decline in physical mobility. Presently, the continued use of the Snellen chart to assess for VA as a part of fall risk assessment may be inadequate. Future studies should focus on developing a more comprehensive clinical assessment of vision that expands beyond visual acuity for the geriatric population