Mid-IR period-magnitude relations for AGB stars

Asymptotic Giant Branch variables are found to obey period-luminosity relations in the mid-IR similar to those seen at K_S (2.14 microns), even at 24 microns where emission from circumstellar dust is expected to be dominant. Their loci in the M, logP diagrams are essentially the same for the LMC and for NGC6522 in spite of different ages and metallicities. There is no systematic trend of slope with wavelength. The offsets of the apparent magnitude vs. logP relations imply a difference between the two fields of 3.8 in distance modulus. The colours of the variables confirm that a principal period with log P > 1.75 is a necessary condition for detectable mass-loss. At the longest observed wavelength, 24 microns, many semi-regular variables have dust shells comparable in luminosity to those around Miras. There is a clear bifurcation in LMC colour-magnitude diagrams involving 24 micron magnitudes.Comment: 5 pages, 4 figure

The effects of acoustic feedback on the spread and decay of supersonic jets.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77257/1/AIAA-1968-80-222.pd

Regulatory Dynamics on Random Networks: Asymptotic Periodicity and Modularity

We study the dynamics of discrete-time regulatory networks on random digraphs. For this we define ensembles of deterministic orbits of random regulatory networks, and introduce some statistical indicators related to the long-term dynamics of the system. We prove that, in a random regulatory network, initial conditions converge almost surely to a periodic attractor. We study the subnetworks, which we call modules, where the periodic asymptotic oscillations are concentrated. We proof that those modules are dynamically equivalent to independent regulatory networks.Comment: 23 pages, 3 figure

04. Population Trends of Breeding Grassland Birds at Midewin National Tallgrass Prairie, 1985–2015

We use data from ongoing bird monitoring programs to assess long-term population trends at Midewin National Tallgrass Prairie in northeastern Illinois. Midewin is the nation’s first National Tallgrass Prairie and was established in 1996 on the site of the former Joliet Army Ammunition Plant. Annual bird monitoring began at the site in the early 1980s when it was discovered that the pastures and hayfields maintained by the Army contained significant grassland bird populations. Ninety-four species of breeding birds were recorded at the site between 2009 and 2015, including large populations of several grasslandobligate birds including dickcissel (Spiza americana), eastern meadowlark (Sturnella magna), grasshopper sparrow (Ammodramus savannarum), bobolink (Dolichonyx oryzivorus), and Henslow’s sparrow (Ammodramus henslowii). Trend analyses showed that populations of bobolink, grasshopper sparrow, and savannah sparrow (Passerculus sandwichensis) were stable on the site between 1985 and 2015, whereas dickcissel and Henslow’s sparrow showed significant population increases during this interval. Three species declined significantly between 1985 and 2015: eastern meadowlark, upland sandpiper (Bartramia longicauda), and vesper sparrow (Pooecetes gramineus). The stable population trends for bobolink, grasshopper sparrow, and savannah sparrow contrast sharply with statewide and regional trends for these species, which show large population declines. The recent introduction of bison to the site may help provide the habitat structure needed to maintain large grassland bird populations at the site

Examining perceptions of agility in software development practice

This is the post-print version of the final published article that is available from the link below. Copyright @ 2010 ACM.Organizations undertaking software development are often reminded that successful practice depends on a number of non-technical issues that are managerial, cultural and organizational in nature. These issues cover aspects from appropriate corporate structure, through software process development and standardization to effective collaborative practice. Since the articulation of the 'software crisis' in the late-1960s, significant effort has been put into addressing problems related to the cost, time and quality of software development via the application of systematic processes and management practices for software engineering. Early efforts resulted in prescriptive structured methods, which have evolved and expanded over time to embrace consortia/ company-led initiatives such as the Unified Modeling Language and the Unified Process alongside formal process improvement frameworks such as the International Standards Organization's 9000 series, the Capability Maturity Model and SPICE. More recently, the philosophy behind traditional plan-based initiatives has been questioned by the agile movement, which seeks to emphasize the human and craft aspects of software development over and above the engineering aspects. Agile practice is strongly collaborative in its outlook, favoring individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a plan (see Sidebar 1). Early experience reports on the use of agile practice suggest some success in dealing with the problems of the software crisis, and suggest that plan-based and agile practice are not mutually exclusive. Indeed, flexibility may arise from this unlikely marriage in an aim to strike a balance between the rigor of traditional plan-based approaches and the need for adaptation of those to suit particular development situations. With this in mind, this article surveys the current practice in software engineering alongside perceptions of senior development managers in relation to agile practice in order to understand the principles of agility that may be practiced implicitly and their effects on plan-based approach

The Aggregation Kinetics of a Simulated Telechelic Polymer

We investigate the aggregation kinetics of a simulated telechelic polymer gel. In the hybrid Molecular Dynamics (MD) / Monte Carlo (MC) algorithm, aggregates of associating end groups form and break according to MC rules, while the position of the polymers in space is dictated by MD. As a result, the aggregate sizes change every time step. In order to describe this aggregation process, we employ master equations. They define changes in the number of aggregates of a certain size in terms of reaction rates. These reaction rates indicate the likelihood that two aggregates combine to form a large one, or that a large aggregate splits into two smaller parts. The reaction rates are obtained from the simulations for a range of temperatures. Our results indicate that the rates are not only temperature dependent, but also a function of the sizes of the aggregates involved in the reaction. Using the measured rates, solutions to the master equations are shown to be stable and in agreement with the aggregate size distribution, as obtained directly from simulation data. Furthermore, we show how temperature induced variations in these rates give rise to the observed changes in the aggregate distribution that characterizes the sol-gel transition.Comment: 9 pages, 10 figure

Metabolite Fingerprinting in Transgenic Nicotiana tabacum Altered by the Escherichia coli Glutamate Dehydrogenase Gene

With about 200 000 phytochemicals in existence, identifying those of biomedical significance is a mammoth task. In the postgenomic era, relating metabolite fingerprints, abundances, and profiles to genotype is also a large task. Ion analysis using Fourier transformed ion cyclotron resonance mass spectrometry (FT-ICR-MS) may provide a high-throughput approach to measure genotype dependency of the inferred metabolome if reproducible techniques can be established. Ion profile inferred metabolite fingerprints are coproducts. We used FT-ICR-MS-derived ion analysis to examine gdhA (glutamate dehydrogenase (GDH; EC 1.4.1.1)) transgenic Nicotiana tabacum (tobacco) carrying out altered glutamate, amino acid, and carbon metabolisms, that fundamentally alter plant productivity. Cause and effect between gdhA expression, glutamate metabolism, and plant phenotypes was analyzed by [Formula: see text] labeling of amino acid fractions, and by FT-ICR-MS analysis of metabolites. The gdhA transgenic plants increased (13)N labeling of glutamate and glutamine significantly. FT-ICR-MS detected 2 012 ions reproducible in 2 to 4 ionization protocols. There were 283 ions in roots and 98 ions in leaves that appeared to significantly change abundance due to the measured GDH activity. About 58% percent of ions could not be used to infer a corresponding metabolite. From the 42% of ions that inferred known metabolites we found that certain amino acids, organic acids, and sugars increased and some fatty acids decreased. The transgene caused increased ammonium assimilation and detectable ion variation. Thirty-two compounds with biomedical significance were altered in abundance by GDH including 9 known carcinogens and 14 potential drugs. Therefore, the GDH transgene may lead to new uses for crops like tobacco

Radiation and String Atmosphere for Relativistic Stars

We extend the Vaidya radiating metric to include both a radiation field and a string fluid. Assuming diffusive transport for the string fluid, we find new analytic solutions of Einstein's field equations. Our new solutions represent an extention of Xanthopoulos superposition.Comment: To appear in Phys. Rev. D, Rapid Communicatio