Some studies on the population dynamics of the bread beetle stegobium paniceum (l) (coleoptera : anobiidae)

Some aspects of the population dynamics of the bread beetle Stegobium paniceum were studied using a laboratory culture of the species. Initial density of adults was found to influence reproductive success, the number of progeny produced by paniceum females decreasing with increased adult density. Using densities ranging from 0.013 - 6.70 adult beetles/g, 0.66 beetles/g was found to be the density above which the number of progeny decreased markedly. Using different immature stages in densities from 0.33 to 40 per g, the egg stage showed the highest apparent mortality, although infertility of eggs was not taken into account. Mortality of the larval stages had little effect on the resulting adult numbers, although when larval density increased above 8.33 per g the mortality rate increased. One of the main factors limiting the population increase was decreased fecundity of females due to mutual interference with oviposition. The frequency of copulation decreased when a density of 12 pairs per dish was exceeded, fecundity of females also being reduced above this density. The capacity for increase r(_c) under the experimental conditions was found to be 0.52/beetle/day with 94% of eggs being laid before the females were 8 days old and the mortality being greatest between days 10 and 16.When females were provided with antennectomised males at comparatively low densities of 0.02 and 0.06 beetles/g, the progeny per female decreased by over 50% compared to that of females provided with normal males. Antennectomised males took longer to find females and to copulate than did control males. More than 90% of the control males copulated within 15 minutes whereas only 5% of antennectomised males copulated within this time

Identifying Topographic Controls of Terrestrial Vegetation Using Remote Sensing Data in a Semiarid Mountain Watershed, Idaho, USA

Global climate change is a significant research focus area in contemporary Earth science. Changes in climatic patterns have already resulted in shifting energy flows with associated changes in hydrologic and ecologic systems. More specifically, changes in vegetation distribution and abundance are one of the most visible and potentially significant effects of a changing climatic regime. However, to monitor and predict future changes in vegetation, the initial conditions must be well characterized. This thesis examines the distribution of vegetation in a semiarid mountain watershed in three important ways: (1) quantifying the factors affecting the distribution of broad classes of vegetation at the hillslope scale (e.g., 30-100 m), (2) quantifying factors affecting the organization of vegetation at sub-hillslope scales, and (3) quantifying the factors influencing the distribution of vegetation water content. The first of these themes is aimed at producing a hillslope-scale classification map of 4 broad classes (sagebrush steppe, Douglas fir, ponderosa pine, and deciduous/riparian) of vegetation within Dry Creek Experimental Watershed (DCEW) at the 30 m spatial resolution using remote sensing and geospatial data, field data, and 2 supervised learning classifiers known as artificial neural network (ANN) and classification and regression tree (CART). We investigated possible drivers of vegetation distribution by partitioning 11 topographic and remote sensing inputs into the ANN and CART models. Results show that the ANN had better overall accuracy (82.3%) than the CART (77.22%); however, it is less informative of the input variables used to classify due to the complex nature of the ANN architecture. Therefore, the CART model was used to determine that 5 of the 11 predictors were significant drivers of vegetation distribution. At the sub-hillslope scale, we quantified the percent cover of specific biotic and abiotic cover types (grass, forb, shrub, bare ground, and etc.) contained within the sagebrush-steppe class: the diameter at breast height (DBH), frequency, and density for the conifer classes; and percent composition and width of the “green line” of riparian reaches. We also investigated influences of topographic effects on abundance within the sagebrush steppe, and Douglas fir and ponderosa pine ecosystems. Preliminary results of sagebrush steppe indicate percent cover of bare ground was 47.89% ± 3.29%, grass was 17.716% ± 4.6%, forb was 13.03% ± 2.3%, and shrub was 16.0% ± 4.09%. Moreover, there was a significant (p =0.05) association between grass cover and topographic aspect, with North slopes having a grass cover of 14.58% ± 7.33% and South slopes with 11.67 % ± 6.0 % at the 95% confidence level (P = 0.05). The average DBH for mature Douglas fir and ponderosa pine was 84.6 cm ± 19.4 and 82.4 cm ± 24.2, respectively. Frequency and density of Douglas fir (\u3e 1.4 m in height) was 100% and 17.57 per 100 m pixel while ponderosa pine was 57.14% and 8.77 per pixel. The most prevalent trends in riparian vegetation suggest that willow and water birch decrease in percent composition with elevation gain, while mountain maple increase in percent composition. Also, the breadth of the “green line” decreases with gaining elevation. Finally, the National Aeronautics and Space Administration (NASA) has been using microwave passive and active remote sensing to develop algorithms to retrieve global soil moisture. However, there are issues with the above ground vegetation over laying the soil in which leaf water content attenuates the signal through the leaves and increases sensitivity to moisture below the top centimeter of the soil surface (Njoku & Li 1999). Therefore, we investigated spatial and temporal changes in the vegetation water content (VWC) of grass/forb life form and the relative vegetation water content (RVWC) of shrubs within the sagebrush steppe ecosystem for NASA’s model development in the Soil Moisture Active Passive (SMAP). Our data suggest that to define this value, calculations are spatially and temporally dependent, and to determine the VWC across DCEW, further data acquisition and processing must be completed

Industrial Arts in Newkirk, Oklahoma

This report deals with the industrial arts curriculum in Newkirk High School, Newkirk, Oklahoma. Courses ot study have been constructed for mechanical drawing and woodwork. Floor plans are included that show the physical facilities of the industrial arts department and an inventory showing the cost of equipment is listed. The courses outlined in this report are intended to be flexible and may be changed to meet the needs of the students. The success ot any industrial arts program is determined by how well the program is planned and administered. The writer has attempted to include material in the proposed courses of study that will meet the needs of the school and community.Industrial Arts Educatio

Direction of photo-electron emission

Direction of emission of photoelectrons from hydrogen, air and argon irradiated by Mo Kα x-rays. — Photographs of the photo-electron tracks in a Wilson expansion chamber through which a narrow beam of monochromatic Mo Kα x-rays were passed were taken with a stereoscopic camera. The direction of the paths with respect to the x-ray beam was determined from measurements made with a specially designed stereoscopic comparator. 445 tracks were studied of which 231 were in argon, 123 in air and 91 in hydrogen. Curves showing the frequency of occurrence of different angles of ejection have a fairly sharp maximum for angles of about 70° with the forward direction of the x-ray beam. The curves are similar for the three gases studied except that the maximum in the case of hydrogen is somewhat sharper than for the other two gases

The direction of ejection of photo-electrons produced by x-rays

Stereoscopic photographs of photo-electrons produced by 40 kv Mo Kα x-rays, were examined by a stereoscopic comparator which gave a quantitative measure of the initial direction of ejection in space. The measurement of twenty-four distinct tracks in a series of twenty-nine pairs of photographs showed that the most probable angle of ejection was about 70° with the primary beam. This supports the view that the electric vector of the radiation plays a very important part in the production of photo-electrons. The small forward or backward component, noticed in many tracks, must come from the random momentum of the electron in its orbit before ejection

The Age-Hardening of Magnesium with Aluminum and Zinc

Magnesium is one of the most active elements and forms oxides, nitrides, and carbides, but not hydrides. Due to its activity, low melting point, low strength when unalloyed, and the difficulty with which it is worked, magnesium has not been and is not at present well developed