The application of specific point energy analysis to laser cutting with 1 μm laser radiation

Specific point energy (SPE) is a concept that has been successfully used in laser welding where SPE and power density determine penetration depth. This type of analysis allows the welding characteristics of different laser systems to be directly compared. This paper investigates if the SPE concept can usefully be applied to laser cutting. In order to provide data for the analysis laser cutting of various thicknesses of mild steel with a 2kW fibre laser was carried out over a wide range of parameter combinations. It was found that the SPE concept is applicable to laser cutting within the range of parameters investigated here

The application of specific point energy analysis to laser cutting with 1 μm laser radiation

Specific point energy (SPE) is a concept that has been successfully used in laser welding where SPE and power density determine penetration depth. This type of analysis allows the welding characteristics of different laser systems to be directly compared. This paper investigates if the SPE concept can usefully be applied to laser cutting. In order to provide data for the analysis laser cutting of various thicknesses of mild steel with a 2kW fibre laser was carried out over a wide range of parameter combinations. It was found that the SPE concept is applicable to laser cutting within the range of parameters investigated here

The Effect of Turfgrass Maintenance on Surface-Water Quality in a Suburban Watershed, Inner Blue Grass, Kentucky

Nutrients and pesticides applied during routine maintenance or establishment of turfgrass could result in nonpoint-source pollution. Nutrient and pesticide concentrations in water exiting a turfgrass management area in the Sinking Creek watershed, a suburban watershed in the Inner Blue Grass Region of central Kentucky, were monitored. This watershed was selected because it contains multiple land uses: agricultural, residential, and recreational (golf course). A survey was conducted to determine the extent to which lawn-care products are used in the residential sector of the watershed. For the golf-course portion, the golf-course superintendent recorded chemical application daily. Runoff from the golf course was sampled in 1993 where the stream exits the golf-course property. Sinking Creek was sampled upstream and downstream of the Tashamingo subdivision from April through October 1996 and January through February 1997. Weekly grab samples and three storm sample sequences (spring, summer, and fall) were analyzed to determine pesticide and nutrient concentrations. The analysis results revealed that few instances of pesticide concentrations in Sinking Creek exceeded minimum detectable levels and none exceeded the U.S. Environmental Protection Agency drinking-water limits during the sampling period. The herbicide 2,4-D was detected in Sinking Creek at both sample locations. In addition to 2,4-D, the insecticide chlorpyrifos was detected at the golf-course exit. Increases in pesticides and nutrients in Sinking Creek coincided with spring application of turfgrass chemicals in the suburban portion of the watershed. Concentrations of nitrogen and phosphorus were low and similar to what would be expected for the land use

Photometric Decomposition of Barred Galaxies

We present a non-parametric method for decomposition of the light of disk galaxies into disk, bulge and bar components. We have developed and tested the method on a sample of 68 disk galaxies for which we have acquired I-band photometry. The separation of disk and bar light relies on the single assumption that the bar is a straight feature with a different ellipticity and position angle from that of the projected disk. We here present the basic method, but recognise that it can be significantly refined. We identify bars in only 47% of the more nearly face-on galaxies in our sample. The fraction of light in the bar has a broad range from 1.3% to 40% of the total galaxy light. If low-luminosity galaxies have more dominant halos, and if halos contribute to bar stability, the luminosity functions of barred and unbarred galaxies should differ markedly; while our sample is small, we find only a slight difference of low significance.Comment: Accepted to appear in AJ, 36 pages, 9 figures, full on-line figures available at http://www.physics.rutgers.edu/~sellwood/Reese.htm

Synthetic Mudscapes: Human Interventions in Deltaic Land Building

In order to defend infrastructure, economy, and settlement in Southeast Louisiana, we must construct new land to mitigate increasing risk. Links between urban environments and economic drivers have constrained the dynamic delta landscape for generations, now threatening to undermine the ecological fitness of the entire region. Static methods of measuring, controlling, and valuing land fail in an environment that is constantly in flux; change and indeterminacy are denied by traditional inhabitation. Multiple land building practices reintroduce deltaic fluctuation and strategic deposition of fertile material to form the foundations of a multi-layered defence strategy. Manufactured marshlands reduce exposure to storm surge further inland. Virtual monitoring and communication networks inform design decisions and land use becomes determined by its ecological health. Mudscapes at the threshold of land and water place new value on former wastelands. The social, economic, and ecological evolution of the region are defended by an expanded web of growing land

Genes of the serotonergic and dopaminergic pathways and their interaction affect the expression of Behavioural and Psychological Symptoms in Dementia (BPSD).

Although there is evidence for the involvement of genes of serotonergic and dopaminergic systems in the manifestation of the Behavioural and Psychological Symptoms in Dementia (BPSD), genetic association studies are contradictory. We used 1008 probable AD patients from the UK and applied a Multiple Indicators Multiple Causes (MIMIC) approach to investigate the effect of 11 polymorphisms in the serotonergic and dopaminergic systems, on four behavioural sub-phenotypes, namely "psychosis"," moods", "agitation" and "behavioural dyscontrol", as well as on 12 NPI items. Significant findings included the association of DRD1 A48G with "psychosis" (p=0.037), the association of DAT1 VNTR with "agitation" (p=0.006) and the association of DRD4 with "moods" sub-phenotype (p=0.008). In addition, associations were identified between DRD1 A48G and DAT1 VNTR with aberrant motor behaviour (AMB) symptoms (p=0.001 and p=0.015 respectively), between DRD4 and sleep disturbances (p=0.018) and between 5HTTLPR and apathy (p=0.033). Finally, significant interactions were observed between COMT Val158Met and 5HTTLPR with "psychosis" (p=0.026), between HTTLPR and STin2 with "psychosis" (p=0.005), between DAT1 3'UTR VNTR and COMT Val158Met with "agitation" (p=0.0001) and between DAT1 3'UTR VNTR and 5HTTLPR with the "moods" factor (p=0.0027). The complexity of the interrelations between genetic variation, behavioural symptoms and clinical variables was efficiently captured by this MIMIC model

The application of specific point energy analysis to laser cutting with 1 μm laser radiation

Specific point energy (SPE) is a concept that has been successfully used in laser welding where SPE and power density determine penetration depth. This type of analysis allows the welding characteristics of different laser systems to be directly compared. This paper investigates if the SPE concept can usefully be applied to laser cutting. In order to provide data for the analysis laser cutting of various thicknesses of mild steel with a 2kW fibre laser was carried out over a wide range of parameter combinations. It was found that the SPE concept is applicable to laser cutting within the range of parameters investigated here

Strong Lensing Analysis of the Cluster RCS0224-0002 at z=0.77z=0.77

We present a detailed mass reconstruction of the cluster RCS0224-0002 at $z=0.773$ from the strong lensing features observed with HST/WFPC2. The mass profile is reconstructed using a parametric approach. We introduce a novel method to fit extended multiple images based on the Modified Hausdorff Distance between observed arcs and the arcs reproduced by the model. We perform the detailed error analysis of the model parameter using the MCMC method. Our model reproduces all the observed strong lensing features of the RCS0224-0002 and predicts the redshift of one of the arcs systems to be $z\approx 2.65$ (the other system has an spectroscopic redshift of $z=4.87$). The reconstructed inner mass profile is well fitted by a non-singular isothermal sphere, rather than with an NFW model. Dark matter substructure, derived from the light distribution of the most luminous cluster members, is crucial for reproducing the complexity of the quadrupole image system, which could not be achieved otherwise. The reconstructed mass distribution closely follows the light, however it is significantly shifted from the X-ray emission of the gas. The mass of RCS0224-0002 derived from the lensing model, $\approx 2\times10^{14} M_\odot$ is in a very good agreement with the one obtained from the X-ray temperature measured with deep Chandra observations.Comment: 13 pages, accepted for A&

‘We have to wait in a queue for our turn quite a bit’ Examining children’s physical activity during primary physical education lessons

The overall purpose of this study was to examine children’s physical activity (PA) during primary physical education (PE). This was achieved through the following two research objectives: (1) to measure children’s PA, lesson context and teacher promotion of PA during PE lessons; and (2) to explore teachers’ and children’s perspectives on PA levels during PE lessons. Evidence suggests that children’s PA during PE is below recommended levels and further research is required to understand the reasons why. Through a mixed method design, 138 children were observed using the System for Observing Fitness and Instruction Time, 80 children participated in group interviews, and 13 teachers were interviewed, across three primary schools in England. Findings indicated that the mean percentage of lesson time allocated to moderate to vigorous PA (MVPA) was 42.4% and the average lesson length was 35.3 minutes. Qualitative themes identified were: ‘knowledge and beliefs’; ‘teacher pedagogy’; and ‘teacher development’. The findings indicate that a change in perspective is needed, which includes a focus on PA during primary PE lessons. Intervention work is required that targets teachers’ knowledge and beliefs towards PE along with the development of effective teaching strategies. However, this needs to be grounded in an ecological approach which will allow researchers and schools to target the various levels of influence. It is strongly recommended that interventions are grounded in behaviour change theory, as this study indicates that sharing knowledge about pedagogical strategies to increase children’s MVPA does not necessarily produce changes in teachers’ behaviours