Inference of historical population-size changes with allele-frequency data

With up to millions of nearly neutral polymorphisms now being routinely sampled in population-genomic surveys, it is possible to estimate the site-frequency spectrum of such sites with high precision. Each frequency class reflects a mixture of potentially unique demographic histories, which can be revealed using theory for the probability distributions of the starting and ending points of branch segments over all possible coalescence trees. Such distributions are completely independent of past population history, which only influences the segment lengths, providing the basis for estimating average population sizes separating tree-wide coalescence events. The history of population-size change experienced by a sample of polymorphisms can then be dissected in a model-flexible fashion, and extension of this theory allows estimation of the mean and full distribution of long-term effective population sizes and ages of alleles of specific frequencies. Here, we outline the basic theory underlying the conceptual approach, develop and test an efficient statistical procedure for parameter estimation, and apply this to multiple population-genomic datasets for the microcrustacean Daphnia pulex

Improving green manure quality with phosphate rocks in Ontario Canada

Phosphate rock (PR) was applied to one conventional and two organic dairy fields and planted with buckwheat (Fagopyrum esculentum) as a green manure crop. In total, five types of PR were applied at three application rates in order to determine the yield, concentration of P in the aboveground tissue and the P uptake of buckwheat. It was found that PR of relatively high carbonate substitution and small particle diameter could increase buckwheat tissue concentrations to a quality such that mineralization of the buckwheat mulch could occur. Buckwheat mulch and residual PR increased soil P flux as determined by anion exchange membranes in situ in the following spring. This provides evidence that buckwheat of high P quality has the potential to supply P to a subsequent crop

Impact of the Spruce Budworm (Lepidoptera: Tortricidae) on the Ottawa and Hiawatha National Forests, 1978-1980

The Michigan Impact Plot System was established during 1978 and 1979 to obtain a data base for quantifying the impact of the spruce budworm in the Ottawa and Hiawatha National Forests. The formulae used to estimate the mean, total, and associated standard errors of the various parameters at the national forest and forest district levels are presented. We present the 1978, 1979, and 1980 impact data for the following parameters; percent mortality, total dead volume. dead volume per ha, live volume per ha, defoliation ranking, frequency and extent of top-kill, and incidence of spruce budworm feeding on saplings and regenera- tion. Statistics from an annual inventory of 108 composite ground sampling units (CGSU) in 1978, and 136 CGSU\u27s in 1979 and 1980 provide a more precise estimate ofthe impact of the spruce budworm in Michigan\u27s Upper Peninsula than ha~ been available to date

An Unprecedented Scientific Community Response to an Unprecedented Event: Tropical Storm Agnes and the Chesapeake Bay

In June 1972, the remnants of Hurricane Agnes brought destructive floods to the watershed of the Chesapeake Bay basin. Unlike Hurricane Isabel, Agnes did not strike Chesapeake Bay directly, but deposited a record amount of rainfall on the watershed. The evening that the Agnes rainfall began in earnest coincided with a meeting of the Citizens Program for the Chesapeake Bay. The directors of the three largest Chesapeake Bay research institutions, Drs. Donald W. Pritchard, L. Eugene Cronin, and William J. Hargis Jr., were in attendance at this meeting. The potential magnitude of the Agnes rainfall was readily apparent at the meeting as one of the planned evening events had to be moved due to a foot of water in the meeting room. The following morning at breakfast, the three directors committed their institutions to “Operation Agnes,” extensive studies of the biological, chemical, and physical impacts of this event. Hargis, Cronin, and Pritchard were good friends and strong competitors of long standing. Since 1949, Pritchard had been the first full-time director of the Chesapeake Bay Institute (CBI); Cronin had headed the Chesapeake Biological Laboratory (CBL) since 1951; and Hargis had been director of the Virginia Institute of Marine Science (VIMS) (and its predecessor the Virginia Fisheries Laboratory-VFL) since 1959. In 1964, the three directors had set up an informal Chesapeake Bay Research Council (CBRC) to coordinate some of their Chesapeake Bay research activities. They used the CBRC mechanism to coordinate “Operation Agnes,” a commitment that was made without any assurance of financial support for these studies. The gamble taken by the three laboratory directors was successful, eventually resulting in a peer-reviewed book published by The Johns Hopkins University Press entitled The Effects of Tropical Storm Agnes on the Chesapeake Bay Estuarine System. Operation Agnes was the last project undertaken by the CBRC. Reorganization by two of the parent institutions and incorporation of the Chesapeake Research Consortium (CRC) resulted in a realignment of Chesapeake Bay scientific leadership and the leadership of Operation Agnes moved from CBRC to CRC. The scientific community’s response to Tropical Storm Agnes—an unprecedented event— was in itself unprecedented. A number of coincidences came into play: recent (1969) experience with flooding from Hurricane Camille; fortuitous attendance of the leaders of the three largest Chesapeake Bay research institutions at a meeting directly affected by Agnes; and the prior mobilization of the three institutions to conduct extensive hydrographic studies throughout Chesapeake Bay. The most important factor, however, was the strong commitment of three laboratory directors to the understanding of the Chesapeake Bay system.https://scholarworks.wm.edu/vimsbooks/1003/thumbnail.jp

Teaching Casual Random Blood Glucose Screening to Second-Year Dental Students

In our project, archived casual random blood glucose levels of second-year dental students who were taught the mechanics of self-testing were retrieved. Material data were analyzed by calculating means, medians, standard deviations, and ranges for 161 dental students screened by this casual and random self-monitoring of blood glucose levels as described by the American Diabetes Association’s 2008 Standards of Medical Care in Diabetes. Three types of data were assessed in this study. The first was the casual blood glucose levels of second-year dental students. The second was the data retrieved from student questionnaires regarding the value of teaching casual random blood glucose screening. The third was the U.S. dental schools’ responses regarding inclusion of casual blood glucose screening in their current curricula. Second-year dental students self-reported hypoglycemia in three instances and hyperglycemia in eight, based on current American Diabetes Association standards. Students agreed or strongly agreed that the value of teaching was informative (92.3 percent), beneficial (95 percent), and something that might be included in their practices (78.2 percent), with 19.2 percent being neutral on the inclusion. Only six U.S. dental schools reported teaching casual random glucose screening