Diffusional drop growth in a supersaturated atmosphere

The effect which a growing droplet has on the supersaturated atmosphere surrounding it is analyzed by assuming a macroscopic diffusional growth mechanism involving both heat and vapor. The problem is solved, for cloud-chamber conditions, first for very short times assuming a fixed radius, and then for longer times assuming the establishment of quasi steady-state conditions. Knowledge of the way in which droplet growth affects supersaturation is important in the evaluation of nucleation rates --Abstract, page ii

Medical Malpractice and Compensation in South Africa

This article gives an overview of current medical malpractice law in South Africa. The following aspects are covered: The overall scheme for preventing and redressing medical errors and adverse events, including regulation, criminal and civil liability, and social and private insurance, and the relationships among these various systems; the details of the applicable liability and compensation systems, including criteria defining qualification for compensation, causation and loss of chance, liability for failure to obtain informed consent, as well as matters of proof and gathering of evidence. The authors note the difficulty they had in obtaining empirical data on medical errors and adverse events. Finally, certain attitudes and concerns about the liability and compensation systems are highlighted

Medical Malpractice and Compensation in South Africa

This article gives an overview of current medical malpractice law in South Africa. The following aspects are covered: The overall scheme for preventing and redressing medical errors and adverse events, including regulation, criminal and civil liability, and social and private insurance, and the relationships among these various systems; the details of the applicable liability and compensation systems, including criteria defining qualification for compensation, causation and loss of chance, liability for failure to obtain informed consent, as well as matters of proof and gathering of evidence. The authors note the difficulty they had in obtaining empirical data on medical errors and adverse events. Finally, certain attitudes and concerns about the liability and compensation systems are highlighted

Theory Of Droplet Growth In Clouds. I. The Transient Stage Of The Boundary-coupled Simultaneous Heat And Mass Transport In Cloud Formation

Two solutions to the system of equations describing the simultaneous heat and mass transport involved in the condensational growth of a droplet in a supersaturated atmosphere are presented. The first, valid for very short times, describes the transient stage of such growth; the second, valid for longer times, presupposes the establishment of a steady-state condition. The two are shown to be complementary for the cases examined. The equations examined satisfy the usual boundary conditions imposed on a drop in a concentric sphere as required by the cellular model for cloud formation. Hence our results can be immediately extended to the treatment of the growth rate of drops in assemblage. © 1970

Shifting distributions and speciation: species divergence during rapid climate change

Questions about how shifting distributions contribute to species diversification remain virtually without answer, even though rapid climate change during the Pleistocene clearly impacted genetic variation within many species. One factor that has prevented this question from being adequately addressed is the lack of precision associated with estimates of species divergence made from a single genetic locus and without incorporating processes that are biologically important as populations diverge. Analysis of DNA sequences from multiple variable loci in a coalescent framework that (i) corrects for gene divergence pre-dating speciation, and (ii) derives divergence-time estimates without making a priori assumptions about the processes underlying patterns of incomplete lineage sorting between species (i.e. allows for the possibility of gene flow during speciation), is critical to overcoming the inherent logistical and analytical difficulties of inferring the timing and mode of speciation during the dynamic Pleistocene. Estimates of species divergence that ignore these processes, use single locus data, or do both can dramatically overestimate species divergence. For example, using a coalescent approach with data from six loci, the divergence between two species of montane Melanoplus grasshoppers is estimated at between 200 000 and 300 000 years before present, far more recently than divergence estimates made using single-locus data or without the incorporation of population-level processes. Melanoplus grasshoppers radiated in the sky islands of the Rocky Mountains, and the analysis of divergence between these species suggests that the isolation of populations in multiple glacial refugia was an important factor in promoting speciation. Furthermore, the low estimates of gene flow between the species indicate that reproductive isolation must have evolved rapidly for the incipient species boundaries to be maintained through the subsequent glacial periods and shifts in species distributions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75592/1/j.1365-294X.2006.03167.x.pd

Navigating the unknown: model selection in phylogeography

Despite the widespread use and obvious strengths of model-based methods for phylogeographic study, a persistent concern for such analyses is related to the definition of the model itself. The study by Peter et al. (2010) in this issue of Molecular Ecology demonstrates an approach for overcoming such hurdles. The authors were motivated by a deceptively simple goal; they sought to infer whether a population has remained at a low and stable size or has undergone a decline, and certainly there is no shortage of software packages for such a task (e.g., see list of programs in Excoffier & Heckel 2006 ). However, each of these software packages makes basic assumptions about the underling population (e.g., is the population subdivided or panmictic); these assumptions are explicit to any model-based approach but can bias parameter estimates and produce misleading inferences if the model does not approximate the actual demographic history in a reasonable manner. Rather than guessing which model might be best for analyzing the data (microsatellite data from samples of chimpanzees), Peter et al. (2010) quantify the relative fit of competing models for estimating the population genetic parameters of interest. Complemented by a revealing simulation study, the authors highlight the peril inherent to model-based inferences that lack a statistical evaluation of the fit of a model to the data, while also demonstrating an approach for model selection with broad applicability to phylogeographic analysis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79081/1/j.1365-294X.2010.04851.x.pd

Species Delimitation Using a Combined Coalescent and Information-Theoretic Approach: An Example from North American Myotis Bats

Coalescent model–based methods for phylogeny estimation force systematists to confront issues related to the identification of species boundaries. Unlike conventional phylogenetic analysis, where species membership can be assessed qualitatively after the phylogeny is estimated, the phylogenies that are estimated under a coalescent model treat aggregates of individuals as the operational taxonomic units and thus require a priori definition of these sets because the models assume that the alleles in a given lineage are sampled from a single panmictic population. Fortunately, the use of coalescent model–based approaches allows systematists to conduct probabilistic tests of species limits by calculating the probability of competing models of lineage composition. Here, we conduct the first exploration of the issues related to applying such tests to a complex empirical system. Sequence data from multiple loci were used to assess species limits and phylogeny in a clade of North American Myotis bats. After estimating gene trees at each locus, the likelihood of models representing all hierarchical permutations of lineage composition was calculated and Akaike information criterion scores were computed. Metrics borrowed from information theory suggest that there is strong support for several models that include multiple evolutionary lineages within the currently described species Myotis lucifugus and M. evotis. Although these results are preliminary, they illustrate the practical importance of coupled species delimitation and phylogeny estimation

Comparison Of Several Aitken Nuclei Counters

The basic thermodynamical processes leading to the formation of droplets in the central part of the Nolan-Pollak counter are analyzed in some detail. The comparison of the UMR-Absolute Aitken Nuclei counter with Nolan-Pollak, General Electric and Gardner counters showed consistently higher counts of the UMR-AAN counter. The mean deviations varied between 20% and 50% depending on the type of the counter, nuclei concentration and nature. Several observations are made on ultrafine particle counting. © 1981

INTEGRATING COALESCENT AND ECOLOGICAL NICHE MODELING IN COMPARATIVE PHYLOGEOGRAPHY

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73659/1/Appendix+S1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/73659/2/j.1558-5646.2007.00117.x.pd