Ian S. E. Carmichael (1930–2011)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95257/1/eost18393.pd

Cashman receives 2006 N. L. Bowen Award

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95516/1/eost15852.pd

The wind speed profile at offshore wind farm sites

Using Monin-Obukhov theory the vertical wind speed profile can be predicted from the wind speed at one height, when the two parameters Monin-Obukhov length and sea surface roughness are known. The applicability of this theory for wind power prediction at offshore sites is investigated using data from the measurement program Rdsand in the Danish Baltic Sea. Different methods to estimate the two parameters are discussed and compared. Significant deviations to the theory are found for near-neutral and stable conditions, where the measured wind shear is larger than predicted. A simple correction method to account for this effect has been developed and tested. As

Classifications of Computable Structures

Let K be a family of structures, closed under isomorphism, in a fixed computable language. We consider effective lists of structures from K such that every structure in K is isomorphic to exactly one structure on the list. Such a list is called a computable classification of K, up to isomorphism. Using the technique of Friedberg enumeration, we show that there is a computable classification of the family of computable algebraic fields, and that with a 0\u27-oracle, we can obtain similar classifications of the families of computable equivalence structures and of computable finite-branching trees. However, there is no computable classification of the latter, nor of the family of computable torsion-free abelian groups of rank 1, even though these families are both closely allied with computable algebraic fields

Can Genetic Estimators Provide Robust Estimates of the Effective Number of Breeders in Small Populations?

The effective population size (N(e)) is proportional to the loss of genetic diversity and the rate of inbreeding, and its accurate estimation is crucial for the monitoring of small populations. Here, we integrate temporal studies of the gecko Oedura reticulata, to compare genetic and demographic estimators of N(e). Because geckos have overlapping generations, our goal was to demographically estimate N(bI), the inbreeding effective number of breeders and to calculate the N(bI)/N(a) ratio (N(a) =number of adults) for four populations. Demographically estimated N(bI) ranged from 1 to 65 individuals. The mean reduction in the effective number of breeders relative to census size (N(bI)/N(a)) was 0.1 to 1.1. We identified the variance in reproductive success as the most important variable contributing to reduction of this ratio. We used four methods to estimate the genetic based inbreeding effective number of breeders N(bI(gen)) and the variance effective populations size N(eV(gen)) estimates from the genotype data. Two of these methods - a temporal moment-based (MBT) and a likelihood-based approach (TM3) require at least two samples in time, while the other two were single-sample estimators - the linkage disequilibrium method with bias correction LDNe and the program ONeSAMP. The genetic based estimates were fairly similar across methods and also similar to the demographic estimates excluding those estimates, in which upper confidence interval boundaries were uninformative. For example, LDNe and ONeSAMP estimates ranged from 14-55 and 24-48 individuals, respectively. However, temporal methods suffered from a large variation in confidence intervals and concerns about the prior information. We conclude that the single-sample estimators are an acceptable short-cut to estimate N(bI) for species such as geckos and will be of great importance for the monitoring of species in fragmented landscapes

A Joint Model for Multistate Disease Processes and Random Informative Observation Times, with Applications to Electronic Medical Records Data

Multistate models are used to characterize individuals\u27 natural histories through diseases with discrete states. Observational data resources based on electronic medical records pose new opportunities for studying such diseases. However, these data consist of observations of the process at discrete sampling times, which may either be pre-scheduled and non-informative, or symptom-driven and informative about an individual\u27s underlying disease status. We have developed a novel joint observation and disease transition model for this setting. The disease process is modeled according to a latent continuous time Markov chain; and the observation process, according to a Markov-modulated Poisson process with observation rates that depend on the individual\u27s underlying disease status. The disease process is observed at informative or non-informative sampling times, with possible misclassification error. We demonstrate that the model is computationally tractable and devise an expectation-maximization algorithm for parameter estimation. Using simulated data, we show how estimates from our joint observation and disease transition model lead to less biased and more precise estimates of the disease rate parameters. We apply the model to a study of secondary breast cancer events, utilizing mammography and biopsy records from a sample of women with a history of primary breast cancer

"Gang of Four" Congressional Intelligence Notifications

Report that reviews the history of the Gang of Four intelligence notification process and compares this procedure with that of the "Gang of Eight" notification procedure

Heat capacities of TiO2-bearing silicate liquids: Evidence for anomalous changes in configurational entropy with temperature

The heat capacities of several TiO2-bearing silicate glasses and liquids containing Cs2O, Rb2O, Na2O, K2O, CaO, MgO, or BaO have been measured to 1100 K using a differential scanning calorimeter and to 1800 K using a Setaram HT-1500 calorimeter in step-scanning mode. The results for liquids of M2O-TiO2-2SiO2 composition (M -- Na, K, Cs) are compared to those for liquids of M2O-3SiO2 composition. The presence of TiO2 has a profound influence on the heat capacity of simple three-component silicate liquids over the temperature range 900-1300 K. Specifically, replacement of Si4+ by Ti4+ leads to doubling of the magnitude of the jump in Cp at the glass transion (Tg); this is followed by a progressive decrease in liquid Cp for over 400 K, until Cp eventually becomes constant and similar to that in Ti-free systems. The large heat capacity step at Tg in the TiO2-bearing melts suggests significant configurational rearrangements in the liquid that are not available to TiO2-free silicates. In addition, these "extra" configurational changes apparently saturate as temperature increases, implying the completion of whatever process is responsible for them, or the attainment of a random distribution of structural states. Above 1400 K, however, where the heat capacities of TiO2-bearing and TiO2-free alkali silicate liquids are similar, their configurational entropies differ by ~3.5 J/g.f.w.-K. The larger configurational entropy of the TiO2-bearing alkali silicate liquids relative to the TiO2-free liquids is energetically equivalent to raising the liquid temperature by more than 300 degrees. This result clearly demonstrates the energetic magnitude of the configurational changes apparent in the supercooled liquid region and their impact on the thermodynamic properties of the stable liquid. Consideration of both density measurements on liquids and spectroscopic data on quenched glasses (from the literature) suggests that the anomalous configurational rearrangements may involve the breakdown of alkali and alkaline earth titanate complexes and changes in Ti4+ coordination.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30728/1/0000377.pd

New density measurements on carbonate liquids and the partial molar volume of the CaCO 3 component

Density measurements on nine liquids in the CaCO 3 –Li 2 CO 3 –Na 2 CO 3 –K 2 CO 3 quaternary system were performed at 1 bar between 555 and 969 °C using the double-bob Archimedean method. Our density data on the end-member alkali carbonate liquids are in excellent agreement with the NIST standards compiled by Janz (1992). The results were fitted to a volume equation that is linear in composition and temperature; this model recovers the measured volumes within experimental error (±0.18% on average, with a maximum residual of ±0.50%). Our results indicate that the density of the CaCO 3 component in natrocarbonate liquids is 2.502 (±0.014) g/cm 3 at 800 °C and 1 bar, which is within the range of silicate melts; its coefficient of thermal expansion is 1.8 (±0.5)×10 −4 K −1 at 800 °C. Although the volumes of carbonate liquids mix linearly with respect to carbonate components, they do not mix linearly with silicate liquids. Our data are used with those in the literature to estimate the value of in alkaline silicate magmas (≥20 cm 3 /mol at 1400 °C and 20 kbar), where CO 2 is dissolved as carbonate in close association with Ca. Our volume measurements are combined with sound speed data in the literature to derive the compressibility of the end-member liquids Li 2 CO 3 , Na 2 CO 3 , and K 2 CO 3 . These results are combined with calorimetric data to calculate the fusion curves for Li 2 CO 3 , Na 2 CO 3 , and K 2 CO 3 to 5 kbar; the calculations are in excellent agreement with experimental determinations of the respective melting reactions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47311/1/410_2003_Article_505.pd