Automated clinical system for chromosome analysis

An automatic chromosome analysis system is provided wherein a suitably prepared slide with chromosome spreads thereon is placed on the stage of an automated microscope. The automated microscope stage is computer operated to move the slide to enable detection of chromosome spreads on the slide. The X and Y location of each chromosome spread that is detected is stored. The computer measures the chromosomes in a spread, classifies them by group or by type and also prepares a digital karyotype image. The computer system can also prepare a patient report summarizing the result of the analysis and listing suspected abnormalities

A reliable Pade analytical continuation method based on a high accuracy symbolic computation algorithm

We critique a Pade analytic continuation method whereby a rational polynomial function is fit to a set of input points by means of a single matrix inversion. This procedure is accomplished to an extremely high accuracy using a novel symbolic computation algorithm. As an example of this method in action we apply it to the problem of determining the spectral function of a one-particle thermal Green's function known only at a finite number of Matsubara frequencies with two example self energies drawn from the T-matrix theory of the Hubbard model. We present a systematic analysis of the effects of error in the input points on the analytic continuation, and this leads us to propose a procedure to test quantitatively the reliability of the resulting continuation, thus eliminating the black magic label frequently attached to this procedure.Comment: 11 pages, 8 eps figs, revtex format; revised version includes reference to anonymous ftp site containing example codes (MapleVr5.1 worksheets) displaying the implementation of the algorithm, including the padematinv.m library packag

The economic performance of cities: a Markov-switching approach

This paper examines the determinants of employment growth in metro areas. To obtain growth rates, we use a Markov-switching model that separates a city’s growth path into two distinct phases (high and low), each with its own growth rate. The simple average growth rate over some period is, therefore, the weighted average of the high-phase and low-phase growth rates, with the weight being the frequency of the two phases. We estimate the effects of a variety of factors separately for the high-phase and low-phase growth rates, along with the frequency of the low phase. We find that growth in the high phase is related to human capital, industry mix, and average firm size. In contrast, we find that growth in the low phase is mostly related to industry mix, specifically, the relative importance of manufacturing. Finally, the frequency of the low phase appears to be related to the level of non-education human capital, but to none of the other variables. Overall, our results strongly reject the notion that city-level characteristics influence employment growth equally across the phases of the business cycle.Business cycles ; Cities and towns

Using flow gauges to determine leaf specific conductance in hybrid poplars under mesic and xeric conditions

Non-Peer ReviewedA study was conducted using sap flow gauges to determine leaf specific conductance (LSC) in hybrid poplars in an environmentally-controlled greenhouse at Swift Current, Saskatchewan. Sap flow rates were compared between CanAm and Walker poplar clones using stem flow gauges. The primary objectives were to verify differences in LSC observed between the clones under moist field conditions in a previous study and to compare the responses in sap flow and LSC within these trees as imposed soil conditions changed from moist to dry. Walker poplars appear to be well-suited to mesic sites, and, under ample soil moisture, perform better than CanAms. However, they are susceptible to mid-season terminal shoot dieback, while CanAm poplars do not seem to be as susceptible. We suspect that this is primarily attributable to a greater LSC of CanAm poplars and possibly achieving better stomatal responses during periods of extended vapor pressure deficits. The gauges were mounted near the base of each tree. Following gauge installation, the trees were watered to field capacity. No additional water was added during the course of the test. Sap flow, leaf water potentials and tree conditions were monitored for 17 days as the soil conditions evolved from moist to dry. Results indicate that the CanAms displayed a greater LSC under moist as well as dry conditions compared to the Walkers. Throughout the testing period, CanAm mid-day leaf water potentials were slightly more negative than for the Walker poplars. Although CanAm poplars appear to be less water efficient than Walkers, they are better able to function and survive during periods of extended vapour pressure deficits

Modelling microelectrode biosensors : free-flow calibration can substantially underestimate tissue concentrations

Microelectrode amperometric biosensors are widely used to measure concentrations of analytes in solution and tissue including acetylcholine, adenosine, glucose and glutamate. A great deal of experimental and modelling effort has been directed at quantifying the response of the biosensors themselves; however, the influence that the macroscopic tissue environment has on biosensor response has not been subjected to the same level of scrutiny. Here we identify an important issue in the way microelectrode biosensors are calibrated that is likely to have led to underestimations of analyte tissue concentrations. Concentration in tissue is typically determined by comparing the biosensor signal to that measured in free-flow calibration conditions. In a free-flow environment the concentration of the analyte at the outer surface of the biosensor can be considered constant. However, in tissue the analyte reaches the biosensor surface by diffusion through the extracellular space. Because the enzymes in the biosensor break down the analyte, a density gradient is set up resulting in a significantly lower concentration of analyte near the biosensor surface. This effect is compounded by the diminished volume fraction (porosity) and reduction in the diffusion coefficient due to obstructions (tortuosity) in tissue. We demonstrate this effect through modelling and experimentally verify our predictions in diffusive environments

Using flow gauges to determine stem and root conductance in hybrid poplars.

Non-Peer ReviewedA study was conducted using sap flow gauges to determine stem and root conductance in hybrid poplars at two sites near Swift Current, Saskatchewan. At the Rushlake site, sap flow rates were compared between CanAm and Walker poplars using Dynamax (Model SGA-10) stem flow gauges. The primary objective was to determine if the difference in susceptibility to midsummer terminal shoot dieback in Walker and CanAm poplar clones could be attributed to leaf-specific conductance. Walker poplars appear to be well-suited to mesic sites and, under good soil moisture conditions, perform better than CanAm . However, they are susceptible to mid-season terminal shoot dieback, while CanAm poplars do not seem to be as susceptible. We suspect that this is primarily attributable to a greater leaf-specific conductance (LSC) of CanAm poplars. As a tertiary cause, perhaps CanAm poplars achieve a more complete stomatal closure during periods of extended vapor pressure deficits. The gauges were mounted at the distal ends (where the shoot diameter is about 10 mm) of actively growing branches near the crown of each tree. For a period of 14 days, the sap flow rates of each tree were measured. Preliminary results indicate that CanAms did indeed have a greater LSC and showed higher stem flow rates than Walker poplars. Under the study conditions at the Rushlake site, air temperatures were not of sufficient magnitude to determine differences in leaf stomatal closure between the CanAm and Walker trees. The LSC characteristics, however, would have benefited the CanAm poplars in functioning under extended vapor pressure deficits. A secondary objective was to determine if differences in root conductances of poplars subjected to varying saline conditions were possible to measure using sap flow gauges. Although great care must be taken during gauge installation on tree roots, we found it is possible to measure root sap conductance on trees subjected to varying levels of salinity

Agri-food leadership case study: Pegasus Bay Wines

This is the fourth case study in a series analysing leadership in New Zealand agrifood companies. It is part of the Unlocking Export Prosperity Research Programme led by the Agribusiness and Economics Research Unit (AERU) at Lincoln University. This case study examines Pegasus Bay, a winery in Waipara Valley founded by Ivan and Chris Donaldson, and now run by the next generation of Donaldsons. Their passion for wine and the craft shines through in the high-quality products they create. They focus on creating wines they enjoy, rather than being led by the market. They have built a strong brand and garnered an international audience through capitalising on sustainable practices and lifting the image of New Zealand. Achieving this has been no coincidence as founders Ivan and Chris Donaldson, and the next generation of Donaldsons – Matthew, Edward, Belinda, and Di – embody the qualities of leadership that support innovation and coordination, and align people to their vision and core purpose. This aligns with previous case studies and the findings of the earlier literature review