Process Efficiency - Adapting Flow to the Agile Improvement Effort

In Scrum, we measure performance using velocity. However, the velocity of one team cannot be compared to the velocity of another, since it is a relative measure that is only of meaning to the team using it. So can we objectively measure the performance of teams? Measuring Value Added Time as a percentage of Total Time is a metric that is used in Lean Manufacturing to help get a better understanding of production processes and optimize those processes. This paper introduces an adaptation of this metric to the Agile environment. Giving teams an objective insight into their efficiency helps them optimize their efficiency and compare themselves to other teams. This adapted metric is called Process Efficiency and is comparable across teams, technologies, and domains of practice

Starburst Galaxies: Why the Calzetti Dust Extinction Law?

The empirical reddening function for starburst galaxies generated by Calzetti and her co-workers has proven very successful, and is now used widely in the observational literature. Despite its success, however, the physical basis for this extinction law, or more correctly, attenuation law remains weak. Here we provide a physical explanation for the Calzetti Law based on a turbulent interstellar medium. In essence, this provides a log-normal distribution of column densities, giving a wide range of column densities in the dusty foreground screen. Therefore, extended sources such as starburst regions or HII regions seen through it suffer a point-to-point stochastic extinction and reddening. Regions of high column densities are "black" in the UV, but translucent in the IR, which leads to a flatter extinction law, and a larger value of the total to selective extinction, R_V. We fit the Calzetti Law, and infer that the variance sigma of the log-normal distribution lies in the range 0.6<sigma<2.2. The absolute to selective extinction R_V is found to be in the range 4.3 to 5.2 consistent with R_V=4.05+/-0.80 of the Calzetti Law.Comment: accepted for publication in ApJ

Large physical spin approach for strongly correlated electrons

We present a novel approach for a systematic large--spin expansion of the $t$-$J$ Hamiltonian which enables us to work without the constraint of no double occupancy. In our scheme we can perform the large--spin limit ensuring that the low energy spin excitations are in {\em exact} correspondence with the physical excitations of the $s={1\over2}$ Hilbert space. As a consequence, we expect a smooth dependence of the physical quantities on the expansion parameter $1/ s$. As a first application of the method we study the case of a single hole in a N\'eel background. A systematic expansion in fluctuations about this stable solution indicates that by increasing $t/J$ the quasiparticle weight strongly depends on the momentum carried by the hole. Results, obtained on small lattice sizes, are found in excellent agreement with exact diagonalization data.Comment: RevTeX 3.0 + 2 postscript figures appended (search for FIG1a and FIG1b ) revised, to appear in Phys. Lett.

Long-term results in pancreatic transplantation with special emphasis on the use of prolamine

Our pancreatic transplantation programme was initiated in 1979. Since then a total of 102 pancreas transplantations have been performed, blocking exocrine secretion using the duct occlusion technique with prolamine. Early non-immunological complications are frequent. The long-term results (9 years) in combined pancreas and kidney transplanted patients are satisfying: the survival rate for pancreas is 38% and 54% for kidney. Patient survival rate in this period is 85%. Beyond the first year post-transplant the exocrine activity disappears whereas the endocrine function remains well preserved

Bow shocks around pulsars and neutron stars

Pulsar wind nebulae are now well established as important probes both of neutron stars' relativistic winds and of the surrounding interstellar medium. Amongst this diverse group of objects, pulsar bow shocks have long been regarded as an oddity, only seen around a handful of rapidly moving neutron stars. However, recent efforts at optical, radio and X-ray wavelengths have identified many new pulsar bow shocks, and these results have consequently motivated renewed theoretical efforts to model these systems. Here I review the new results and ideas which have emerged on these spectacular systems, and explain how bow shocks and "Crab-like" nebulae now form a consistent picture within our understanding of pulsar winds.Comment: 12 pages, 2 embedded EPS figures, 1 GIF figure. Advances in Space Research, in pres

Direct comparison of distinct naive pluripotent states in human embryonic stem cells

Until recently, human embryonic stem cells (hESCs) were shown to exist in a state of primed pluripotency, while mouse embryonic stem cells (mESCs) display a naive or primed pluripotent state. Here we show the rapid conversion of in-house-derived primed hESCs on mouse embryonic feeder layer (MEF) to a naive state within 5-6 days in naive conversion media (NCM-MEF), 6-10 days in naive human stem cell media (NHSM-MEF) and 14-20 days using the reverse-toggle protocol (RT-MEF). We further observe enhanced unbiased lineage-specific differentiation potential of naive hESCs converted in NCM-MEF, however, all naive hESCs fail to differentiate towards functional cell types. RNA-seq analysis reveals a divergent role of PI3K/AKT/mTORC signalling, specifically of the mTORC2 subunit, in the different naive hESCs. Overall, we demonstrate a direct evaluation of several naive culture conditions performed in the same laboratory, thereby contributing to an unbiased, more in-depth understanding of different naive hESCs

Pharmacoepidemiology and the Australian regional prevalence of multiple sclerosis

Background: Over some 50 years, field surveys have shown that the prevalence of multiple sclerosis (MS) increases with increasing distance from the equator in both the northern and the southern hemispheres. Such a latitudinal gradient has been found in field surveys of MS prevalence carried out at different times in various local regions of Australia

Islet isolation assessment in man and large animals

Recent progress in islet isolation from the pancreas of large mammals including man, accentuated the need for the development of precise and reproducible techniques to assess islet yield. In this report both quantitative and qualitative criteria for islet isolation assessment were discussed, the main topics being the determination of number, volume, purity, morphologic integrity and in vitro and in vivo function tests of the final islet preparations. It has been recommended that dithizone should be used as a specific stain for immediate detection of islet tissue making it possible to estimate both the total number of islets (dividing them into classes of 50 μ diameter range increments) and the purity of the final preparation. Appropriate morphological assessment should include confirmation of islet identification, assessment of the morphological integrity and of the purity of the islet preparation. The use of fluorometric inclusion and exclusion dyes together have been suggested as a viability assay to simultaneously quantitate the proportion of cells that are intact or damaged. Perifusion of islets with glucose provides a dynamic profile of glucose-mediated insulin release and of the ability of the cells to down regulate insulin secretion after the glycemic challenge is interrupted. Although perifusion data provides a useful guide to islet viability the quantity and kinetics of insulin release do not necessarily predict islet performance after implantation. Therefore, the ultimate test of islet viability is their function after transplantation into a diabetic recipient. For this reason, in vivo models of transplantation of an aliquot of the final islet preparation into diabetic nude (athymic) rodents have been suggested. We hope that these general guidelines will be of assistance to standardize the assessment of islet isolations, making it possible to better interpret and compare procedures from different centers. © 1990 Casa Editrice il Ponte

Low heat conduction in white dwarf boundary layers?

X-ray spectra of dwarf novae in quiescence observed by Chandra and XMM-Newton provide new information on the boundary layers of their accreting white dwarfs. Comparison of observations and models allows us to extract estimates for the thermal conductivity in the accretion layer and reach conclusions on the relevant physical processes. We calculate the structure of the dense thermal boundary layer that forms under gravity and cooling at the white dwarf surface on accretion of gas from a hot tenuous ADAF-type coronal inflow. The distribution of density and temperature obtained allows us to calculate the strength and spectrum of the emitted X-ray radiation. They depend strongly on the values of thermal conductivity and mass accretion rate. We apply our model to the dwarf nova system VW Hyi and compare the spectra predicted for different values of the thermal conductivity with the observed spectrum. We find a significant deviation for all values of thermal conductivity that are a sizable fraction of the Spitzer conductivity. A good fit arises however for a conductivity of about 1% of the Spitzer value. This also seems to hold for other dwarf nova systems in quiescence. We compare this result with thermal conduction in other astrophysical situations. The highly reduced thermal conductivity in the boundary layer requires magnetic fields perpendicular to the temperature gradient. Locating their origin in the accretion of magnetic fields from the hot ADAF-type coronal flow we find that dynamical effects of these fields will lead to a spatially intermittent, localized accretion geometry at the white dwarf surface.Comment: 8 pages, 5 figs, to appear in Astronomy & Astrophysic