Volumetric real-time particle-based representation of large unstructured tetrahedral polygon meshes

In this paper we propose a particle-based volume rendering approach for unstructured, three-dimensional, tetrahedral polygon meshes. We stochastically generate millions of particles per second and project them on the screen in real-time. In contrast to previous rendering techniques of tetrahedral volume meshes, our method does not need a prior depth sorting of geometry. Instead, the rendered image is generated by choosing particles closest to the camera. Furthermore, we use spatial superimposing. Each pixel is constructed from multiple subpixels. This approach not only increases projection accuracy, but allows also a combination of subpixels into one superpixel that creates the well-known translucency effect of volume rendering. We show that our method is fast enough for the visualization of unstructured three-dimensional grids with hard real-time constraints and that it scales well for a high number of particles

Comparison of scanning Kelvin probe with SEM/EPMA techniques for fingermark recovery from metallic surfaces

Most traditional techniques to recover latent fingermarks from metallic surfaces do not consider the metal surface properties and instead focus on the fingermark chemistry. The scanning Kelvin probe (SKP) technique is a non-contact, non-destructive method, used under ambient conditions, which can be utilised to recover latent prints from metallic surfaces and does not require any enhancement techniques or prevent subsequent forensic analysis. Where a fingermark ridge contacted the metal, the contact potential difference (CPD) contrast between the background surface and the fingermark contact area was 10-50mV. Measurements were performed on the untreated brass, nickel-coated brass and copper metal surfaces and compared to traditional forensic enhancement techniques such as Vacuum Metal Deposition (VMD) using Au-Zn and Au-Ag. Using VMD, the CPD change ranged from 0 to 150mV between the dissimilar metal surfaces affected by the fingermark. In general, SKP worked best without additional enhancement techniques. Scanning Electron Microscope (SEM) scans were used to identify the fingermark contact areas through a sodium, chlorine and oxygen electron probe micro-analyzer (EPMA). The fingermark was observed in the backscattered electron image as the carbon deposits scattered the electrons less than the surrounding metal surface. The fingermark is shown clearly in a Cathodoluminescence scan on the copper sample as it blocks the photon emission at band gap (2.17eV) from the underlying copper oxide (Cu2O) surface. For the first time, SEM, EPMA and Cathodoluminescence techniques were compared to SKP data. Visible and latent fingermarks were tested with latent, eccrinous fingermarks more easily imaged by SKP. Results obtained were very encouraging and suggest that the scanning Kelvin probe technique, which does not need vacuum, could have a place as a first stage analysis tool in serious crime investigation.</p

Effects of improved street lighting on crime

Improved street lighting serves many functions and is used in both public and private settings. The prevention of personal and property crime is one of its objectives in public space, which is the main focus of this review. There are two main theories of why improved street lighting may cause a reduction in crime. The first suggests that improved lighting leads to increased surveillance of potential offenders (both by improving visibility and by increasing the number of people on the street) and hence to increased deterrence of potential offenders. The second suggests that improved lighting signals community investment in the area and that the area is improving, leading to increased community pride, community cohesiveness, and informal social control. The first theory predicts decreases in crime especially during the hours of darkness, while the second theory predicts decreases in crime during both daytime and nighttime. Results of this review indicate that improved street lighting significantly reduces crime. This lends support for the continued use of improved street lighting to prevent crime in public space. The review also found that nighttime crimes did not decrease more than daytime crimes. This suggests that a theory of street lighting focusing on its role in increasing community pride and informal social control may be more plausible than a theory focusing on increased surveillance and increased deterrence. Future research should be designed to test the main theories of the effects of improved street lighting more explicitly, and future lighting schemes should employ high quality evaluation designs with long-term followups

The Effect of Muscle Energy Technique on Hamstring Extensibility: The Mechanism of Altered Flexibility

Purpose: To investigate the effectiveness of muscle energy technique in increasing passive knee extension and to explore the mechanism behind any observed change. Procedure: 40 asymptomatic subjects were randomly allocated to control or experimental groups. Subjects lay supine with their thigh fixed at 90° flexion, and the hamstring muscle stretched to the onset of discomfort by passive knee extension. Knee range of motion was recorded with digital photography and passive torque recorded with a hand-held dynamometer. The experimental group received muscle energy technique to the hamstring muscle, after which the resistance to stretch and the range of motion were again measured. The knee was extended to the original passive torque and the angle at the knee recorded. If the onset of discomfort was not produced at this angle, the knee was further extended and the new angle was recorded. Results: A significant increase in range of motion was observed at the knee (p< 0.019) following a single application of MET to the experimental group. No change was observed in the control group. When an identical torque was applied to the hamstring both before and after the MET, no significant difference in range of motion of the knee was found in the experimental group. Conclusions: Muscle energy technique produced an immediate increase in passive knee extension. This observed change in range of motion is possibly due to an increased tolerance to stretch as there was no evidence of visco-elastic change

Prisoner Mothers

There can be few more emotional issues in penology than female prisoners’ relationships with their children. Two situations need to be considered. Firstly, when the child is an infant, say, up to three years of age, there are problems concerning mother and child living together during mother’s imprisonment.</jats:p