6,694 research outputs found
Macrobiota — helminths as active participants and partners of the microbiota in host intestinal homeostasis
Important insights have recently been gained in our understanding of the intricate relationship in the intestinal milieu between the vertebrate host mucosal immune response, commensal bacteria, and helminths. Helminths are metazoan worms (macrobiota) and trigger immune responses that include potent regulatory components capable of controlling harmful inflammation, protecting barrier function and mitigating tissue damage. They can secrete a variety of products that directly affect immune regulatory function but they also have the capacity to influence the composition of microbiota, which can also then impact immune function. Conversely, changes in microbiota can affect susceptibility to helminth infection, indicating that crosstalk between these two disparate groups of endobiota can play an essential role in host intestinal immune function and homeostasis
Comments on Estimating Population Rate of Increase from Age Frequency Data
Although many papers have described assumptions and calculations of r from different kinds of data, none has compared estimates of r for the same real data set under different assumptions. We used the age distributions of gray foxes collected during six trapping seasons to estimate and compare r and lâ‚“ series derived under different assumptions. Because trapped foxes are killed, they are believed by some to represent death history data. We found this treatment underestimates mortality so overestimates survivorship and leads to erroneous conclusions about the population. Use of a projection matrix allowed prediction of population size and thus allowed us to predict observed rate of increase. Use of projection matrices also resulted in the most conservative estimated of r
Cartographic Trend Analysis of Furbearer Harvest Distributions in Arkansas
Average by-county fur harvest for the last nine harvest seasons (1977-1985) was used as data points to be interpolated using nearest neighbor algorithms in computer-assisted trend analyses. COMPLOT maps were produced which represented a surface of harvest densities drawn over a map of Arkansas. Twelve furbearer species are examined, and topographic features of harvest density for each are interpreted in terms of ecology and/or buyer distribution. The trend surface technique removed some of the error inherent to harvest records, and produced an aesthetic graphical display of the information that was more easily interpreted and explained than other methods of analysis usually allow
Mensural Discrimination of the Skulls of Arkansas Peromyscus
Twelve parameters were measured on skulls of four species of Peromyscus from Arkansas. Univariate statistical tests, multivariate analyses of variance, and principal axis factor analyses were performed on the data set and/or subsets in a search for species-level discriminating characters. Total length of skull was found to discriminate between skulls of P. maniculatis, P. leucopus, and a combined group of P. attwateri and P. gossypinus. Furthermore, the ratio of interorbital width and length of nasal bone was found to adequately discriminate between skulls of P. attwateri and P. gossypinus
Grain Marketing Tools: A Survey of Illinois Grain Elevators
As with most sectors of the agriculture economy, the U. S. country grain elevator industry has experienced considerable consolidation and concentration. By the same token, the country elevator's customer base (grain producers and landlords) has also changed rather dramatically as grain production takes place on larger and fewer farms. The profitability of operating a country elevator is directly related to the volume of grain the country elevator purchases over the course of a marketing year. Because the basic services offered by country elevators are very similar (purchasing, conditioning and storing grain), country elevators attempt to differentiate themselves from their competition by offering customers a variety of cash grain marketing tools. These tools range from the basic cash forward contracts to minimum price contracts to the so called 'new generation grain marketing contracts'. The primary focus of this paper is to determine the marketing contracts grain elevators offer to their customers and the extent to which these contracts are used by the elevator's customers. Additionally, the types grain contracts offered will be compared to the firm's storage capacity, business organization, size of customer base, geographic location and type of grain purchased.Crop Production/Industries, Marketing,
The Design of an Uncertainty Model For The Tidal Constituent and Residual Interpolation (TCARI) Method for Tidal Correction of Bathymetric Data
Recent advances in processing multibeam sonar data brought about by the Combined Uncertainty and Bathymetric Estimator (CUBE) [1] have demonstrated the value of identifying and tracking survey uncertainties. Most of these uncertainties were outlined in Hare, Godin, and Mayer uncertainty model developed in 1995 [2]. That report identified the uncertainties in the various electronic systems used to acquire the bathymetric data. However, one of the largest contributors to the overall error budge t in a near coastal hydrographic survey is that contributed by water level uncertainty. As the ocean mapping industry pushes for ever finer spatial details in its data, the traditional method of discrete tide zoning [3] must be abandoned for a more robust method that can match the requirements of the data. The method currently under investigation by the National Oceanic and Atmospheric Administration is the Tidal Constituent And Residual Interpolation (TCARI) method [4]. TCARI has the ability to interpolate the water level at a vessel’s position for any location and instance in time. It can also produce a gridded water level surface of the entire survey area. While the potential of this method is encouraging, a rigorous investigation of the uncertainties associated with it has yet to be completed. This research seeks to close that gap by examining the uncertainties in this method, using both observed water level information from around the country as well as data acquired during the original 1995 NOS Kinematic GPS experiment in Galveston Bay, Texas [5]
An Infestation of the Bat Bug Cimex pilosellus on an Arkansas Population of Big Brown Bats (Eptesicus fuscus)
Accessing Rydberg-dressed interactions using many-body Ramsey dynamics
We demonstrate that Ramsey spectroscopy can be used to observe
Rydberg-dressed interactions. In contrast to many prior proposals, our scheme
operates comfortably within experimentally measured lifetimes, and accesses a
regime where quantum superpositions are crucial. The key idea is to build a
spin-1/2 from one level that is Rydberg-dressed and another that is not. These
levels may be hyperfine or long-lived electronic states. An Ising spin model
governs the Ramsey dynamics, for which we derive an exact solution. Due to the
structure of Rydberg interactions, the dynamics differs significantly from that
in other spin systems. As one example, spin echo can increase the rate at which
coherence decays. The results also apply to bare (undressed) Rydberg states as
a special case, for which we quantitatively reproduce recent ultrafast
experiments without fitting
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