Aerosol particles, especially in the high Arctic are still not very well represented in climate models. Particle size and number concentrations are strongly under-predicted and temporal variations of aerosol composition and size are still not very well understood, mainly due to the sparsity of observations. The main objective of this thesis is the characterization of the high Arctic summer aerosol by means of electron microscopy in order to extend the existing data set from previous expeditions by size resolved data on aerosol number, morphology and chemical composition and to gain a better understanding of the evolution of the aerosol in the atmosphere. Ambient aerosol was collected over the pack ice during the Arctic Summer Cloud and Ocean (ASCOS) campaign to the high Arctic in summer 2008. Aerosol particles were evaluated with scanning electron microscopy and subsequent digital image processing to assess particle size and morphology. More than 3900 aerosol particles from 9 sampling events were imaged with scanning electron microscopy and merged into groups of similar morphology which contributed to different degrees to the total aerosol: single particles (82%), gel particles (11%) and halo particles (7%). Single particles were observed over the whole size range with a maximum at 64 nm in diameter, gel particles appeared &gt; 45 nm with a maximum in number at 174 nm, halo particles appeared &gt; 75 nm with a maximum in number at 161 nm. The majority of particles showed the morphology of marine gels, no sea salt or otherwise crystalline particles were observed. Transmission electron microscopy enabled more subtle insights into particle morphology and allowed further subdivision of gel particles into aggregates, aggregates with film and mucus-like particles. Energy dispersive X-ray spectroscopy of individual particles revealed a gradual transition in the content of Na+/K+ and Ca2+/Mg2+ between particle morphologies. Single particles and aggregate particles preferentially contained Na+/K+ whereas aggregate with film particles and mucus-like particles mainly contained Ca2+/Mg2+ suggesting a connection between particle morphology and ion content. Back-trajectory analysis was used to identify aerosol sources and to understand the evolution of the aerosol as a function of the synoptic weather situation. Particle numbers, size and morphology changed with the days the air mass spent over the pack-ice. A morphological descriptor applied to gel particles showed a clear trend suggesting that the contour of the particles becomes sharper and more distinct with increased time spent over the pack-ice. For a very long time over the pack-ice, however, we observed a morphology comparable to freshly emitted particles suggesting aerosol sources over the inner pack-ice. Size resolved aerosol chemical composition measurements were utilized to investigate the inorganic composition of laboratory generated nascent sea spray aerosol particles and ambient aerosol samples collected during ASCOS. A significant enrichment of Ca2+ was observed in submicrometer particles in either case with a tendency for increasing Ca2+ enrichment with decreasing particle size. This has strong implications for the alkalinity of sea spray aerosol particles with consequences for the sulfur chemistry in the marine boundary layer, the hygroscopicity and thus the potential of sea spray aerosol particles to act as cloud condensation nuclei. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

The purpose of this study was to evaluate Lewis (2016) simple method to determine hydraulic conductivity in soil samples. This was conducted by comparing Lewis method to a slug-test, Guelph permeameter and calculations from grain size analysis in order to find out if the method is a reliable source for measuring hydraulic conductivity. Other parameters to compare is time consumption, cost effectiveness and area of use. Four different samples were used in the testing, a sand, two tills and pyrite ash (which is a rest product from manufacturing sulfite pulp). The results indicated that measurements in the homogenic sand all methods was in a good range of each other, while in the more heterogenic till the slug-test and Lewis method was close and the calculations from grainsize analysis was much lower. Only grainsize analysis was performed on the pyrite ash and the results was similar to Lewis method. This study shows that Lewis method works well as a reliable source for K measurements and is less time consuming than all the other methods. The material required for the method can be obtained in a hardware store.

Abstract In 2007, an adaptive grazing management process began on the Santa Rita Experimental Range (SRER) in southern Arizona with a primary management objective to reduce repeated defoliation of perennial bunchgrass plants during the summer growing season. In order to follow defoliation events, 1400 individual plants were identified in 6 pastures scheduled for summer grazing from June 15 to October 2, 2013. Plant height and diameter categories were measured before cattle entered each pasture and were re-measured daily or alternate days throughout the grazing period. The differences between heights and diameters were used to calculate any regrowth that occurred. Of the 1400 plants marked, 738 (52.7%) were not defoliated, 453 (32.3%) plants were defoliated once, 199 (14.2%) plants were defoliated twice, and 10 (0.7%) plants were defoliated three-times for a total of 881 defoliation events recorded. The majority of first defoliation events and first incidences of second defoliation occurred on day 3. Cattle began switching their grazing strategy from undefoliated plants to new growth of previously defoliated plants by day 9 with 48 of a total 161 previously defoliated plants being defoliated. The highest number of second defoliations were measured on day 11 when 115 plants were observed as having been defoliated for a second time and 5 plants were defoliated for a third time. Arizona cottontop (Digitaria californica) had a higher percentage of both single and multiple defoliation events when compared to the other perennial grass species. Distance from a permanent water source was not found to have a significant impact on the number of defoliations that an individual plant received. Plants defoliated the first time were taller and had a larger circumference (21.0±5.6 cm and 40.8±9.0 cm) than plants that were re-defoliated (15.5±5.6 cm and 31.4±9.0 cm). This study found that the planned 10 day SRER grazing rotation, when followed, would minimize multiple defoliations by cattle on perennial bunchgrasses.

Animals in general vary immensely in body size, which greatly affects their morphology, physiology, survival, and nutritional requirements. The nervous system is also affected by variation in body size, which, in turn, shapes the perception of environmental stimuli and the behavior of animals. Comparative studies of vertebrates suggest that larger brains and their integrative centers comprise more and generally larger neurons (Jerison, 1973; Kaas, 2000), but much less is known about brain - body size relations in invertebrates. Closely related social bee species are well suited to study correlations between body size and brain composition. Different honey bee species vary in body size yet differ little in their ecological requirements and behavior and bumble bees feature a large range of body sizes even within a single colony.

The mechanisms that control growth processes in biology tissues have attracted continuous research interest despite their complexity. With the emergence of big data experimental approaches there is an urgent need to develop statistical and computational models to fit the experimental data and that can be used to make predictions to guide future research. In this work we apply statistical methods on growth process of different biological tissues, focusing on development of neuron dendrites and tumor cells. We first examine the neuron cell growth process, which has implications in neural tissue regenerations, by using a computational model with uniform branching probability and a maximum overall length constraint. One crucial outcome is that we can relate the parameter fits from our model to real data from our experimental collaborators, in order to examine the usefulness of our model under different biological conditions. Our methods can now directly compare branching probabilities of different experimental conditions and provide confidence intervals for these population-level measures. In addition, we have obtained analytical results that show that the underlying probability distribution for this process follows a geometrical progression increase at nearby distances and an approximately geometrical series decrease for far away regions, which can be used to estimate the spatial location of the maximum of the probability distribution. This result is important, since we would expect maximum number of dendrites in this region; this estimate is related to the probability of success for finding a neural target at that distance during a blind search. We then examined tumor growth processes which have similar evolutional evolution in the sense that they have an initial rapid growth that eventually becomes limited by the resource constraint. For the tumor cells evolution, we found an exponential growth model best describes the experimental data, based on the accuracy and robustness of models. Furthermore, we incorporated this growth rate model into logistic regression models that predict the growth rate of each patient with biomarkers; this formulation can be very useful for clinical trials. Overall, this study aimed to assess the molecular and clinic pathological determinants of breast cancer (BC) growth rate in vivo.

Master of Science / Department of Grain Science and Industry / Charles R Stark / The uniformity of a feed mixture is determined from the coefficient of variation (CV) of ten samples in a single batch of feed. The feed industry standard is a %CV of less than 10 using a single source tracer such as salt, trace minerals or iron filings. The uniformity of mix can be affected by many factors including ingredient properties, equipment design, mix time, sampling method, sample preparation and overall precision of method. The objectives of this thesis were to verify the chloride ion test by the Quantab® chloride titrator method and to determine the effect of extended mixing time, salt particle size, sample preparation, wet mix time, spray condition, application time of the liquid addition, percent liquid addition and mixer type on the uniformity of mix. The first experiment evaluated the effect of water temperature, technician, extraction time, dissolution time on the chloride ion test by the Quantab® chloride titrator method. The salt concentration was significantly affected by water temperature and dissolution time. The results of Experiment 1 demonstrated the 60ºC water temperature and the 30 s extraction time by stirring followed by immediately placing the strip into the solution after extraction should be used for the Quantab® chloride titrator method. The second experiment evaluated the effect of extended mix time, particle size of salt and sample preparation on the %CV. The extended mix time did not result in segregation (P > 0.30). However, particle size of the salt and sample preparation significantly affected the uniformity of mix. The results of Experiment 2 indicated that the extended mix time of up to 60 minutes did not increase the %CV of the feed; the particle size of the salt used in the uniformity of mix test can significantly change the results of the test; and grinding the sample prior to analysis improved the precision of the Quantab® chloride titrator method when coarse salt is used in the manufacturing process. The third experiment evaluated the effect of wet mix time and the timing of the liquid addition using different spray conditions on the %CV. The wet mix time significantly changed the %CV of the mixture (P = 0.0057). The use of a spray nozzle had no effect on the %CV of the feed mixture when a 1.14% of a 23% saline solution was sprayed on to the feed (P = 0.7435). The results of Experiment 3 indicated the wet mix time had a greater influence on the uniformity of mix than the type of nozzle used to apply the liquid; and the shorter liquid application time allowed more time for the mechanical shear of the ribbons and paddles to break up the agglomerated wet particles and distribute them throughout the feed mixture when the total time of the liquid addition plus wet mix time was fixed. The fourth experiment evaluated the effect of different percent liquid addition, application time and mixer type with different wet mix times on the uniformity of mix. The %CV of feed mixed using a fixed wet mix time setting did not change when the percent liquid addition was increased, while the %CV of the feed mixed using a fixed total liquid mix time setting increased when increasing the percent liquid addition. The %CV of feed mixed with a ribbon mixer did not change when the liquid application time was decreased while the %CV of the feed mixed with a paddle mixer increased when decreasing the liquid application time. Differences were observed in the %CV based on the parameters of liquid cycle time, mixer type and mixer size. The results of Experiment 4 indicated the liquid addition time and the percent of liquid addition affected the uniformity of mix. The uniformity of liquid application should be tested with the highest percent liquid addition. Furthermore, application and wet mix times should be determined for each mixer type and size to establish the optimal batch cycle.

Martensitic phase transformation in NiTi shape memory alloys (SMA) occurs over a hierarchy of spatial scales, as evidenced from observed multiscale patterns of the martensitic phase fraction, which depend on the material microstructure and on the size of the SMA specimen. This paper presents a methodology for the multiscale tracking of the thermally induced martensitic phase transformation process in NiTi SMA. Fine scale stochastic phase field simulations are coupled to macroscale experimental measurements through the compound wavelet matrix method (CWM). A novel process for obtaining CWM fine scale wavelet coefficients is used that enhances the effectiveness of the method in transferring uncertainties from fine to coarse scales, and also ensures the preservation of spatial correlations in the phase fraction pattern. Size effects, well-documented in the literature, play an important role in designing the multiscale tracking methodology. Molecular dynamics (MD) simulations are employed to verify the phase field simulations in terms of different statistical measures and to demonstrate size effects at the nanometer scale. The effects of thermally induced martensite phase fraction uncertainties on the constitutive response of NiTi SMA is demonstrated.

This is a demographic study of Nigeria between 1952-1982. Relationships between population growth and economic development are described in detail. Comparisons are made of demographic growth in Nigeria with other developing countries, particularly those in Africa. Population pressure, the condition of the rural areas, and some internal and external population problems are discussed in length. The government's position and the public view on population control and family planning programs are also examined. Current programs of family limitation are discussed and evaluated. The study concludes with recommendations for solutions. Emphasis is placed on the need for immediate recognition and action. Various solutions, particularly education, are evaluated.

Généralement, dans les situations d’hypothèses multiples on cherche à rejeter toutes les hypothèses ou bien une seule d’entre d’elles. Depuis quelques temps on voit apparaître le besoin de répondre à la question : « Peut-on rejeter au moins r hypothèses ? ». Toutefois, les outils statisques pour répondre à cette question sont rares dans la littérature. Nous avons donc entrepris de développer les formules générales de puissance pour les procédures les plus utilisées, soit celles de Bonferroni, de Hochberg et de Holm. Nous avons développé un package R pour le calcul de la taille échantilonnalle pour les tests à hypothèses multiples (multiple endpoints), où l’on désire qu’au moins r des m hypothèses soient significatives. Nous nous limitons au cas où toutes les variables sont continues et nous présentons quatre situations différentes qui dépendent de la structure de la matrice de variance-covariance des données. / Generally, in multiple endpoints situations we want to reject all hypotheses or at least only one of them. For some time now, we see emerge the need to answer the question : "Can we reject at least r hypotheses ?" However, the statistical tools to answer this new problem are rare in the litterature. We decide to develop general power formulas for the principals procedures : Bonferroni’s, Hochberg’s and Holm’s procedures. We also develop an R package for the sample size calculation for multiple endpoints, when we want to reject at least r hypotheses. We limit ourselves in the case where all the variables are continuous and we present four different situations depending on the structure of the data’s variance-covariance matrix.

This research is the result of the author’s quest to answer the question whether Corporate Governance is effective in Emerging Markets. Literature on Corporate Governance in the emerging markets of Latin America is limited mostly due to the relatively slower development of capital markets and the late adoption of corporate governance principles. Corporate Governance laws, which largely follow Sarbanes Oxley guidelines, were published and implemented in the mid 00´s and no research has checked their impact on corporate value in Latin America. This research reports compromises two empirical projects. The first project focused on the relationship between boards of directors attributes such size and composition, Corporate Governance law and firm value for Colombia. The second project focused on another Corporate Governance variable, CEO Duality and tested whether it has had any impact in Mexico. This second project also studied whether board attributes such as size and composition and Corporate Governance law were related to firm value. Based on the listed companies from Colombia and Mexico for the years 2001 to 2012 the author found no relationship between board size or composition and firm value. Results from Mexico, where CEO duality is allowed showed that it has no relationship with firm value. These results do not support or contradict either Agency theory or stewardship theory. Results on the impact of the adoption of a Corporate Governance law in firm value are mixed. Results for Colombia contradict previous literature by reporting a positive relationship between Corporate Governance laws and firm results while results from Mexico support previous research by reporting no relationship between these variables. This research is valuable for regulators and policy makers in their quest to assess the impact of the adoption of Corporate Governance laws in emerging markets. . Since effective Corporate Governance is important in easier access to financing it is important for shareholders to know which Corporate Governance mechanisms are positively related to firm value. Similarly, it is also important for investors (both foreign and local) in assessing the risk for equity investments in Colombia and Mexico.