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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Spatial and temporal assessment of atmospheric organic carbon and black carbon concentrations at South African DEBITS sites / P. Maritz

Maritz, P January 2014 (has links)
The baseline of uncertainty in aerosol radiative forcing is large and depends on aerosol characteristics (e.g. size and composition), which can vary significantly on a regional scale. Sources (natural and anthropogenic) can be directly linked to the aerosol characteristics of a region, making monitoring campaigns to determine aerosol composition in different regions very important. Limited data currently exists for atmospheric aerosol black carbon (BC) and organic carbon (OC) in South Africa. In this study, BC and OC concentrations were explored in terms of spatial and temporal patterns, mass fractions of BC and OC of the overall aerosol mass, as well as possible sources. Primary pollutants, of which BC is an example, are emitted directly from the source. Certain primary pollutants can react with other pollutants to form secondary pollutants. OC can either be a primary or secondary pollutant, e.g. formed by gas-to-particle conversion of volatile organic compounds (VOCs) in the atmosphere (nucleation and condensation of gaseous precursors). Greenhouse gases (GHG) and BC absorb terrestrial long wave radiation causing an increase of atmospheric temperature. In contrast, OC generally reflects incoming radiation, cooling the atmosphere. GHGs have a long residence time in the atmosphere (10 to 100 years), while the residence time of aerosols is usually only a week or more. The climatic effects of aerosols are therefore particularly important from a regional perspective. Aerosols are also important from an air quality perspective, especially since ultrafine particles (diameter smaller than 100nm) are small enough to go through the membranes of the respiratory tract and into the blood stream. They can then be transported to the brain. Up to 2005, DEBITS (Deposition of Biogeochemical Import Trace Species) activities in South Africa did not include aerosol measurements. In order to initiate aerosol monitoring, campaigns were launched during the 2005 to 2007 period. Additionally, OC and BC measurements for the PM10 and PM2.5 (particulate matter smaller than or equal to 10 and 2.5 μm, respectively) fractions were started in 2009. PM10 and PM2.5 samples were collected at five sampling sites in South Africa operated within the DEBITS network, i.e. Louis Trichardt, Skukuza, Vaal Triangle, Amersfoort and Botsalano, with MiniVol samplers. The selected sites are mostly located in rural areas, but with the surrounding atmosphere influenced by industries, transportation, biomass burning, etc. Winters are characterised by an increase in biomass burning (fires) and combustion for domestic use (cooking and space heating). Samples were analysed with a Thermal/Optical Carbon analyser (Desert Research Institute). OC and BC results showed that the total carbonaceous content decreased during the summer due to less biomass burning (fires). BC was the highest at the industrially influenced sites, while OC was highest at regional background sites. OC was higher than BC concentrations at all sites in both size fractions. Most OC and BC occurred in the PM2.5 fraction. OC/BC ratios reflected the setting of the different DEBITS sites, with sites in or close to anthropogenic source regions having the lowest OC/BC ratios, while background sites had the highest OC/BC ratios. The OC mass fraction percentage of the total aerosol weight varied up to 24% and the BC up to 12%. The highest OC mass fraction was found at Skukuza, which was attributed to both natural (lies within the savannah biome) and anthropogenic (dominant path of air mass movement from the anthropogenic industrial hub of South Africa) reasons. The highest mass fraction of BC was found in the Vaal Triangle, since it is situated within a well-known anthropogenic source region. Household combustion for space heating and cooking also seemed to make a significant contribution to BC at this site in the cold winter months. A relatively well-defined seasonal pattern was observed, with higher OC and BC concentrations measured from May to October, which coincides with the dry season in the interior of South Africa. Positive correlations between OC and BC concentrations with the distance back trajectories passed fires were observed, indicating that fires contribute significantly to both atmospheric OC and BC during the burning season. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
32

Spatial and temporal assessment of atmospheric organic carbon and black carbon concentrations at South African DEBITS sites / P. Maritz

Maritz, P January 2014 (has links)
The baseline of uncertainty in aerosol radiative forcing is large and depends on aerosol characteristics (e.g. size and composition), which can vary significantly on a regional scale. Sources (natural and anthropogenic) can be directly linked to the aerosol characteristics of a region, making monitoring campaigns to determine aerosol composition in different regions very important. Limited data currently exists for atmospheric aerosol black carbon (BC) and organic carbon (OC) in South Africa. In this study, BC and OC concentrations were explored in terms of spatial and temporal patterns, mass fractions of BC and OC of the overall aerosol mass, as well as possible sources. Primary pollutants, of which BC is an example, are emitted directly from the source. Certain primary pollutants can react with other pollutants to form secondary pollutants. OC can either be a primary or secondary pollutant, e.g. formed by gas-to-particle conversion of volatile organic compounds (VOCs) in the atmosphere (nucleation and condensation of gaseous precursors). Greenhouse gases (GHG) and BC absorb terrestrial long wave radiation causing an increase of atmospheric temperature. In contrast, OC generally reflects incoming radiation, cooling the atmosphere. GHGs have a long residence time in the atmosphere (10 to 100 years), while the residence time of aerosols is usually only a week or more. The climatic effects of aerosols are therefore particularly important from a regional perspective. Aerosols are also important from an air quality perspective, especially since ultrafine particles (diameter smaller than 100nm) are small enough to go through the membranes of the respiratory tract and into the blood stream. They can then be transported to the brain. Up to 2005, DEBITS (Deposition of Biogeochemical Import Trace Species) activities in South Africa did not include aerosol measurements. In order to initiate aerosol monitoring, campaigns were launched during the 2005 to 2007 period. Additionally, OC and BC measurements for the PM10 and PM2.5 (particulate matter smaller than or equal to 10 and 2.5 μm, respectively) fractions were started in 2009. PM10 and PM2.5 samples were collected at five sampling sites in South Africa operated within the DEBITS network, i.e. Louis Trichardt, Skukuza, Vaal Triangle, Amersfoort and Botsalano, with MiniVol samplers. The selected sites are mostly located in rural areas, but with the surrounding atmosphere influenced by industries, transportation, biomass burning, etc. Winters are characterised by an increase in biomass burning (fires) and combustion for domestic use (cooking and space heating). Samples were analysed with a Thermal/Optical Carbon analyser (Desert Research Institute). OC and BC results showed that the total carbonaceous content decreased during the summer due to less biomass burning (fires). BC was the highest at the industrially influenced sites, while OC was highest at regional background sites. OC was higher than BC concentrations at all sites in both size fractions. Most OC and BC occurred in the PM2.5 fraction. OC/BC ratios reflected the setting of the different DEBITS sites, with sites in or close to anthropogenic source regions having the lowest OC/BC ratios, while background sites had the highest OC/BC ratios. The OC mass fraction percentage of the total aerosol weight varied up to 24% and the BC up to 12%. The highest OC mass fraction was found at Skukuza, which was attributed to both natural (lies within the savannah biome) and anthropogenic (dominant path of air mass movement from the anthropogenic industrial hub of South Africa) reasons. The highest mass fraction of BC was found in the Vaal Triangle, since it is situated within a well-known anthropogenic source region. Household combustion for space heating and cooking also seemed to make a significant contribution to BC at this site in the cold winter months. A relatively well-defined seasonal pattern was observed, with higher OC and BC concentrations measured from May to October, which coincides with the dry season in the interior of South Africa. Positive correlations between OC and BC concentrations with the distance back trajectories passed fires were observed, indicating that fires contribute significantly to both atmospheric OC and BC during the burning season. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
33

Studies using B± → Dh± decays in the LHCb Run I data

Hill, Donal Patrick January 2015 (has links)
Using data equivalent to an integrated luminosity of 3 fb<sup>−1</sup> collected by the LHCb experiment during Run I (2011-2012), studies of beauty mesons decaying to a final state containing open charm are performed, concluding with a number of new results. Direct CP-violation is explored in <i>B</i><sup>±</sup> → <i>Dh</i><sup>±</sup> decays through several measurements of CP violating observables, where the charmed meson <i>D</i> is reconstructed in both 2-track and 4-track final states. A measurement of the <i>B</i><sup>±</sup> production asymmetry at LHCb is reported using <i>B</i><sup>±</sup> → <i>D</i>π<sup>±</sup> decays, and a complementary measurement of the CP asymmetry in <i>B</i><sup>±</sup> → <i>J</i>/ψ<i>K</i><sup>±</sup> decays made. A search for the rare <i>B</i><sub>c</sub>− → <i>D</i>(*)π<sup>−</sup> and B<sub>c</sub>− → <i>D</i> (*)<i>K</i><sup>−</sup> decays concludes this work.
34

The Importance of Image to Boston College Students

Garber, Shelby Lee January 2013 (has links)
Thesis advisor: Paul Gray / There is an image associated with BC students that most, if not all, undergraduates can describe. Though the more superficial explanation only includes expensive preppy brand names, Apple products, and working out at the Plex, the BC image is more multifaceted. A study of consumerism, fashion, status, narcissism, collective consciousness, the self and the generalized other, and even Jesuit ideals provides the theoretical background to the analysis. The data were collected through focus group interviews, surveys, pictures, and observations to form a complete idea of BC image. This thesis explores the many sources of this image, its definition, and the extent to which students identify with it. / Thesis (BA) — Boston College, 2013. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Sociology Honors Program. / Discipline: Sociology.
35

Hybrid Pre-coded ST-BC MIMO-CDMA System with Semi-blind Channel Estimation

Liao, Chong-Zhih 30 August 2011 (has links)
In this thesis, a novel pre-coded direct-sequence code division multiple access (DS-CDMA) associated with the multiple-input multiple-output (MIMO) antennas, along with Alamouti¡¦s space-time block code (ST-BC) is considered. In the transmitter, the idea of hybrid pre-coded is exploited; it can be employed to counteract the inter-symbol interference (ISI) introduced by the channel fading duo to multipath propagation, and can be used to exacting the full information of channel impulse response (CIR) in the receiver for semi-blind channel estimation. Under this transceiver framework, we develop a semi-blind adaptive MIMO-CDMA receiver, based on the linearly constrained constant modulus (LCCM) criterion, for symbol recovery. Furthermore, to reduce the complexity of receiver design, the framework of the generalized sidelobe canceller (GSC) associated with the recursive least-squares (RLS) algorithm is adopted, and the gradient approach is applied to track the desired user¡¦s amplitude, simultaneously, and is named as the GSC-CM-IQRD-RLS algorithm. Via computer simulations, the superior performance and the advantages of proposed scheme is verified; it outperforms the conventional LCMV-based algorithm, and slightly better than the convention CM-GSC-RLS receiver, with the paid of spectral efficient.
36

New Directions In The Direction Of Time

Bagci, Gokhan Baris 01 August 2006 (has links) (PDF)
This thesis analyzes the direction of time problem in the framework of philosophy of science. The radiation arrow, Newtonian arrow, thermodynamic arrow and quantum mechanical arrow have been studied in detail. The importance of the structure of space-time concerning direction of time is emphasized.
37

Theoretical Terms And The Ontic Structural Realism

Kaya, Nevzat 01 December 2009 (has links) (PDF)
The main purpose of the present study is to show that scientific realism is still worth advocating despite its vulnerability in the face of anti-realist objections. For, it does not seem possible to &lsquo / do science&rsquo / without realist commitments. The second purpose of this study is to investigate the plausibility of the novel versions of realism in the sense that whether they can satisfactorily respond to the anti-realist objections. Regarding the main purpose, I try to show that theoretical terms are neither reducible to observables nor they can be dispensed with. Hence in scientific theories there always remains a metaphysical part. Regarding the second purpose I discuss ontic structural realism which holds the individualistic attributions responsible for the metaphysical parts in theories and suggests that non-individualistic interpretation of theoretical terms is possible. The legitimacy of Ontic structural realism&rsquo / s suggestion, as its advocates claim, lies within quantum facts.
38

The Rise and Demise of J.H. Todd and Sons, British Columbia’s Enduring Independent Salmon Canners

Fitzgerald, Mickey 04 September 2015 (has links)
This thesis examines J. H. Todd & Sons Ltd., a British Columbia family-owned and run fish packing company during the years 1881 through 1954. The research presented in this paper outlines the contribution of individual Todd family members to both the success and eventual demise of the company. Also examined is the history of the B. C. salmon canning industry, the evolution of J. H. Todd & Sons Ltd., the role of the company in the broader context of the B. C. fishing industry; and the factors that led to the demise of the company. This thesis relies on documentary primary sources as well as an extensive oral history collection obtained from Todd family members and employees. / Graduate / 0334 / 0509 / 0510 / micfitz@shaw.ca
39

A Review of Student Progress Reports in BC: Aligning the 'Report Card' with the BC Education Plan

Beloin, Sharon 17 November 2015 (has links)
A review of British Columbia’s legislation and annual reports from the Ministries responsible for K-12 education in BC has found six different purposes of the report card over time. They include: teacher accountability; assisting the child to evaluate growth; encouragement of parents to co-operate with the teacher; improvement of home and school relationship; easy comparison of students to each other and to standards; and transferability of student achievement information. Four teachers interviewed identified the purpose of the report card as communicating to parents what their child is doing in the classroom and they are using e-portfolios to do so. They found that e-portfolios can allow for more personalized reporting for teachers and students and can address many of the legislated purposes of the report card but do not easily address comparison of students to each other and to standards or transferability of student achievement information. / Graduate / 0515 / 0520 / sbeloin@uvic.ca
40

Type II Diabetes and KCNQ1 mutations in First Nations people of northern British Columbia

Polanco Paniagua, Fernando de Jesus 04 September 2012 (has links)
Background: A novel mutation (V205M) within the KCNQ1 gene was previously delineated and confirmed to predispose to long QT syndrome (LQTS) in a First Nations community in Northern British Columbia (Gitxsan). LQTS is an autosomal dominant genetic disease that is named for the elongation of the ECG (electrocardiogram) Q-T interval, corrected for rate, but is reflective of delayed repolarization predisposing to LQTS. Clinically, LQTS presents as sudden loss of consciousness (fainting, seizures) and sudden death. KCNQ1 is responsible in part for IKs the slow rectifying potassium channel in the heart, and also accounts for about 30% percent of all genetically confirmed cases of LQTS. The KCNQ1 gene is also expressed in the pancreas, and recent Genome Wide Association Studies (GWAS) have identified variants found within the KCNQ1 gene to be strongly associated with type 2 diabetes (T2D) in Asian and European populations. In Canada, and around the world, Indigenous populations have the higher rates of T2D. We set out to determine if the V205M mutation could influence the development of T2D in this First Nations population. Methods: Participants were recruited from a contact data base from the original study (entitled ‘The Impact of Long QT on First Nations People of Northern British Columbia’) and invited to determine if their KCNQ1 mutation status influenced their HbA1c values, and therefore risk for diabetes. Body mass index (BMI), waist circumference (WC), exercise levels and HbA1c test values were collected from each participant. Sixty-five participants (18 mutation positive and 47 mutation negative) were included in this sub-study. Results: Adjusting for anthropometric measurements, V205M+ participants were almost ten times more likely to attain an ‘at-risk’ (or ‘pre-diabetic’) HbA1c value (adjusted OR: 9.62; p=0.002; CI: 2.23-41.46). Although there was no difference in average HbA1C levels (p=0.963). The distribution of values was markedly different between those in the mutation positive vs mutation negative group. Conclusion: Although it is premature to declare a true risk for diabetes in this cross-sectional study, our results suggest that HbA1C levels are influenced by the presence of the V205M mutation, and further study is indicated to determine if insulin secretion is affected in these individuals. This work has potential implications for others with LQTS who might have altered glycemic control as a result of mutations in KCNQ1. Furthermore, in this First Nations population, broader health implications might need to be considered for those with the V205M mutation. / Graduate

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