Improvement of an integral equation method in plane elasticity through modification of source density representation

Integral equation method with continuous functions for calculating boundary stress components in plane elasticit

An Evaluation of Management Options for the Clover Root Curculio (Sitona hispidulus), a Pest of Alfalfa (Medicago sativa) in the Intermountain West

The clover root curculio (CRC) is an important forage pest throughout North America. Extensive larval feeding on host roots has been associated with reduced stand establishment, disruption of nutrient and water uptake, increased secondary plant pathogen infection, decreased winter plant survival, and reductions in forage quality and yield. Due to the hidden nature of larvae in the soil, CRC is often overlooked and integrated pest management programs are limited as there is a lack of management options. First, I surveyed northern Utah alfalfa for CRC natural enemies, particularly insect-attacking nematodes and fungi (entomopathogens) that could be used in biological control programs against CRC larvae. I found Beauveria spp. fungi most commonly infecting CRC larvae belowground. Next, I used recent information on the CRC life cycle in the Intermountain West to test multiple field applications of soil-active biological insecticides (entomopathogenic nematodes, fungi, and bacteria) and a synthetic systemic insecticide, flupyradifurone. Although these insecticides were compatible with spray equipment and alfalfa production, applications of these products did not reduce CRC larval populations or root damage in my studies. Further, the two application timings tested (before larval peak and during larval peak) did not increase application effectiveness. However, evaluating CRC suppression in the field was challenging because they are hidden in the soil, have patchy distributions, and were observed in low numbers. Lastly, I tested existing root-pathogen resistant alfalfa varieties for potential cross-resistance to CRC, and evaluated alfalfa currently being bred at Cornell University for specific resistance to CRC larvae. Although commercial root-pathogen resistant alfalfa had no effect on CRC, the CRC-resistant alfalfa developed at Cornell University may alleviate the impact of CRC larval damage through increased nodule production. This research provides the groundwork for finding effective and long-term management solutions for CRC in the Intermountain West and will assist in the continued development of insecticide application programs and resistant host plants to ultimately improve alfalfa production

Some physico-chemical and biological characteristics of soil and water samples of part of the Niger Delta area, Nigeria

Environmental conditions that influence biocorrosion in the Niger Delta area of Nigeria are investigated experimentally by analysing the physico-chemical and biological characteristics of four (4) soil samplesand water samples taken from ten (10) selected river bodies in the region. Measured properties of the water samples and the corresponding results are pH (4.5 to 6.5), temperature (26.9 to 28.7 0C), electrical conductivity (18.9 to 156.4us/cm), turbidity (19 to 48NTU), redox potential (-372 to +202mV), TDS (78 to 8450mg/l), TOC (17.3 to 38.7mg/l), nitrate ions (6.1 to 17.0mg/l), sulphate ions (0.8 to 13.6mg/l), DO (4.1 to 5.7mg/l), and microbial population (105 to 106 cfu/ml), while those of the soil samples are water content (37 to 51%), organic matter (9.4 to 18.9% dry weight), nitrate ions (0.71 to 1.82 mg/l), sulphate ions (2.1 to 5.8 mg/l) and microbial population (104 to 106 cfu/g). It shown through comparison of experimental results with literature that the levels of the measured properties for both water and soil correspond to an environment that promotes biocorrosio

Investigation Of The Microbial-Induced Corrosion Potential Of Soils In Southern Ijaw Lga In Niger Delta, Nigeria

Investigation of sulphate-reducing bacteria induced corrosion potential of soils along 18-inch 45km Tebidaba/Brass underground oil pipeline in Southern Ijaw LGA of Bayelsa State, Nigeria, is carried out experimentally. The analysis involves determination of some physico-chemical parameters of soils in the pipeline route, and testing corrosion products formed on the surfaces of X60 steel coupon buried in the soils for one year. It is shown that the soils are clayey in nature and highly corrosive with high population of sulphate-reducing bacteria (104 – 106 cfu/g). The ranges of other measured properties of the soils (pH (4.8 – 5.2), temperature (17 – 21oC), water content (79 – 89 %), organic matter (10.7 – 15.6 % dry wt), redox potential (–79 to –95mV), sulphate (0.8 – 13.6mg/l)) favour growth of sulphate-reducing bacteria. Black deposits on the surfaces of the buried coupons are iron sulphide resulting from attack on the metal by sulphate-reducing bacteria in the soils. Keywords: sulphate-reducing bacteria; soil; corrosion; pipeline; crude oilGlobal Journal of Pure and Applied Sciences Vol. 14 (3) 2008: pp. 325-33

Studies in the suitability of NPK-15-15-15 fertilizer, animal dung, and petroleum agar as Nutrient Supplements for growth of microorganisms

The suitability of three nutrient supplements (NPK-15-15-15 fertilizer, petroleum agar, and animal (cattle) dung) in promoting growth of microorganisms in produced water and crude-oil-contaminated soil are investigated experimentally. The analysis involves monitoring the total microbial count (TMC) in produced water and crude-oil-contaminated soil samples treated with the different nutrient supplements. After a test period of 10 weeks, the TMC in produced water treated with NPK, petroleum agar, and cattle dung was 105 cfu/ml, 103 cfu/ml, and 102 cfu/ml respectively; while the TMC in soil treated with NPK, petroleum agar, and cattle dung was 104 cfu/g, 10 cfu/g, and 102 cfu/g respectively. NPK-15-15-15 fertilizer exhibits the best characteristics as nutrient supplement for the microorganisms in both the produced water and crude-oil-contaminated soil; followed by petroleum agar and then cattle dung for produced water, but followed by cattle dung and then petroleum agar for crude-oil-contaminated soil. Keywords: NPK fertilizer; Petroleum agar; Cattle dung; Microbes; Nutrient.Global Journal of Pure and Applied Sciences Vol. 14 (3) 2008: pp. 285-28

Sex Differences in Intimacy Levels in Best Friendships and Romantic Partnerships

Objectives: Close romantic and friendship relationships are crucial for successful survival and reproduction. Both provide emotional support that can have significant effects on an individual’s health and wellbeing, and through this their longer term survival and fitness. Nonetheless, the factors that create and maintain intimacy in close relationships remain unclear. Nor is it entirely clear what differentiates romantic relationships from friendships in these terms. In this paper, we explore which factors most strongly predict intimacy in these two kinds of relationship, and how these differ between the two sexes. Results: Aside from best friendships being highly gendered in both sexes, the dynamics of these two types of relationships differ between the sexes. The intimacy of female relationships was influenced by similarity (homophily) in many more factors (notably dependability, kindness, mutual support, sense of humour) than was the case for men. Some factors had opposite effects in the two sexes: gift-giving had a negative effect on women’s friendships and a positive effect on men’s, whereas shared histories had the opposite effect. Conclusion: These results confirm and extend previous findings that the dynamics of male and female relationships are very different in ways that may reflect differences in their functions

Density fluctuations in κ\kappa-deformed inflationary universe

We study the spectrum of metric fluctuation in $\kappa$-deformed inflationary universe. We write the theory of scalar metric fluctuations in the $\kappa-$deformed Robertson-Walker space, which is represented as a non-local theory in the conventional Robertson-Walker space. One important consequence of the deformation is that the mode generation time is naturally determined by the structure of the $\kappa-$deformation. We expand the non-local action in $H^2/\kappa^2$, with $H$ being the Hubble parameter and $\kappa$ the deformation parameter, and then compute the power spectra of scalar metric fluctuations both for the cases of exponential and power law inflations up to the first order in $H^2/\kappa^2$. We show that the power spectra of the metric fluctuation have non-trivial corrections on the time dependence and on the momentum dependence compared to the commutative space results. Especially for the power law inflation case, the power spectrum for UV modes is weakly blue shifted early in the inflation and its strength decreases in time. The power spectrum of far-IR modes has cutoff proportional to $k^3$ which may explain the low CMB quadrupole moment.Comment: final revision; 19 pages, 3 figures; to appear in Phys. Rev.

Red Noise in Anomalous X-ray Pulsar Timing Residuals

Anomalous X-ray Pulsars (AXPs), thought to be magnetars, exhibit poorly understood deviations from a simple spin-down called "timing noise". AXP timing noise has strong low-frequency components which pose significant challenges for quantification. We describe a procedure for extracting two quantities of interest, the intensity and power spectral index of timing noise. We apply this procedure to timing data from three sources: a monitoring campaign of five AXPs, observations of five young pulsars, and the stable rotator PSR B1937+21.Comment: submitted to the proceedings of the "40 Years of Pulsars" conferenc