Cell-Wall Density of Douglas-Fir by Two Optometric Methods

The change in cell-wall density from the water-swollen (1.0 g/cm3) to the oven-dry (1.43 g/cm3) condition is a function of the percent of shrinkage in the cell wall. Cell-wall density obtained opto-metrically by the Dual-Linear measuring micrometer and the dot-grid eyepiece compared favorably with densities reported for mercury porisimeter or picnometric techniques. Both optometric techniques are nondestructive and offer advantages over destructive techniques. Void volumes in the dry cell wall were calculated to be approximately 3.5%, fiber saturation point for extractive-free cell wall about 35%, Average interfibrillar spacing in the water-swollen condition was 20 Å for both earlywood and latewood and in the dry wall: spacing was 4.7 Å for earlywood and 8.3 Å for latewood

Structure and lattice dynamics of the wide band gap semiconductors MgSiN2_{2} and MgGeN2_{2}

We have determined the structural and lattice dynamical properties of the orthorhombic, wide band gap semiconductors MgSiN$_{2}$ and MgGeN$_{2}$ using density functional theory. In addition, we present structural properties and Raman spectra of a MgSiN$_{2}$ powder. The structural properties and lattice dynamics of the orthorhombic systems are compared to wurtzite AlN. We find clear differences in the lattice dynamics between MgSiN$_{2}$, MgGeN$_{2}$ and AlN, for example we find that the highest phonon frequency in MgSiN$_{2}$ is about 100~cm$^{-1}$ higher than the highest frequency in AlN and that MgGeN$_{2}$ is much softer. We also provide the Born effective charge tensors and dielectric tensors of MgSiN$_{2}$, MgGeN$_{2}$ and AlN. Phonon related thermodynamic properties, such as the heat capacity and entropy, are in very good agreement with available experimental results.Comment: 9 pages, 11 figures, 6 table

Exhaust of Underexpanded Jets from Finite Reservoirs

We examine the response of an underexpanded jet to a depleting, finite reservoir with experiments and simulations. An open-ended shock tube facility with variable reservoir length is used to obtain images of nitrogen and helium jet structures at successive instances during the blowdown from initial pressure ratios of up to 250. The reservoir and ambient pressures are simultaneously measured to obtain the instantaneous pressure ratio. We estimate the time-scales for jet formation and reservoir depletion as a function of the specific heat ratio of the gas and the initial pressure ratio. The jet structure formation time-scale is found to become approximately independent of pressure ratio for ratios greater than 50. In the present work, no evidence of time-dependence in the Mach disk shock location is observed for rates of pressure decrease associated with isentropic blowdown of a finite reservoir while the pressure ratio is greater than 15. The shock location in the finite- reservoir jet can be calculated from an existing empirical fit to infinite-reservoir jet data evaluated at the instantaneous reservoir pressure. For pressure ratios below 15, however, the present data deviate from a compilation of data for infinite-reservoir jets. A new fit is obtained to data in the lower pressure regime. The self-similarity of the jet structure is quantified and departure from similarity is noted to begin at pressure ratios lower than about 15, approximately the same ratio which limits existing empirical fits

Revenue divergence and competitive balance in a divisional sports league

The North American model of resource allocation in professional sports leagues is adapted for English (association) football. The theoretical relationship between revenue and competitive balance is shown to be robust with respect to changes in teams’ objectives and labour market conditions. Empirical revenue functions are reported for 1926-1999. These indicate a shift in the composition of demand favouring big-city teams and an increase in the sensitivity of revenue to performance. An analysis of match results in the FA Cup competition suggests an increase in competitive imbalance between teams at different levels of the league’s divisional hierarchy, as the theory suggests

Cigarette Smoking and the Risk of Bladder Cancer in Men and Women

Although cigarette smoking is a principal risk factor for bladder cancer in both men and women, few studies have statistically evaluated whether gender modifies the effect of smoking on bladder cancer risk. We initiated the present case-control study at Roswell Park Cancer Institute in Buffalo, New York, U.S., to provide further data on this important issue. We observed similar risk estimates for men and women with comparable smoking exposures, but did not observe a statistically significant interaction between gender and lifetime smoking exposure. We conclude that cigarette smoking is a major risk factor for bladder cancer in both sexes, but that gender does not modify the effect of smoking on bladder cancer risk

Development of a Grazing Land Management Education Program for Northern Australia’s Grasslands and Grassy Woodlands

Recognition of the potential to enhance grazing land management to meet the goal of sustainable beef production has been increasing over the past decade. Recognition of the relationship between poor land management and negative off-site environmental impacts, such as soil erosion and a decline in the condition of rivers and adjacent near shore coastal areas from sediment transport, has increased also. This concern has matured somewhat to include the critical link between land condition and production, and the threat to sustainable carrying capacity that comes from declining land condition. Concurrently, interest has increased in optimising the use of pasture, e.g. through the development of infrastructure (watering points, fencing), through more pro-active management e.g. alternative grazing systems, spelling of pastures, and through pasture development. In fact, it can be argued that achieving production goals while improving and maintaining the health of the land has become the major on-property issue for northern Australian graziers

Surveillance imaging of grade 1 astrocytomas in children: can duration and frequency of follow-up imaging and the use of contrast agents be reduced?

Purpose: The optimum strategy for the surveillance of low-grade gliomas in children has not been established, and there is concern about the use of gadolinium-based contrast agents (GBCAs), particularly in children, due to their deposition in the brain. The number of surveillance scans and the use of GBCAs in surveillance of low-risk tumours should ideally be limited. We aimed to investigate the consistency and utility of our surveillance imaging and also determine to what extent the use of GBCAs contributed to decisions to escalate treatment in children with grade 1 astrocytomas. / Methods: This was a retrospective single-centre study at a tertiary paediatric hospital. All children with a new diagnosis of a non-syndromic World Health Organization (WHO) grade 1 astrocytoma between 2007 and 2013 were included, with surveillance imaging up to December 2018 included in analysis. The intervals of surveillance imaging were recorded, and imaging and electronic health records were examined for decisions related to treatment escalation. / Results: Eighty-eight patients had 690 surveillance scans in the study period. Thirty-one patients had recurrence or progression leading to treatment escalation, 30 of whom were identified on surveillance imaging. The use of GBCAs did not appear to contribute to multidisciplinary team (MDT) decisions in the majority of cases. / Conclusion: Surveillance imaging could be reduced in number and duration for completely resected cerebellar tumours. MDT decisions were rarely made on the basis of post-contrast imaging, and GBCA administration could therefore potentially be restricted in the setting of surveillance of grade 1 astrocytomas in children

Neuronal regulation of cochlear blood flow in the guinea‐pig.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110011/1/tjp19944803563.pd

Staring into the abyss? The state of UK rugby's Super League

Rugby League's Super League was formed in 1995, due to unprecedented turmoil experienced in rugby league in Australia and a desire to run a season parallel to the Australian game during the British summer. The predicted outcomes of the Super League included greater uncertainty of outcome, increased attendances, and higher revenues for clubs, ultimately leading to the transformation of rugby league from a northern minority sport into a national/international sport. However, twenty years on, it appears that the Super League is running short of the objectives that it set itself. This paper analyses the financial health of Super League clubs alongside trends in attendance and participation. In summary, all three indicators of performance are poor in relation to the objectives set. These factors point to a bleak future for the sport and rugby league needs to produce a sustainable business model to keep both the clubs and the sport alive