Statistical downscaling of air quality models using Principal Fitted Components

Statistical downscaling is a technique that is used to extract high-resolution information from regional scale variables produced by Chemical Transport Models (CTMs). The aim of this thesis is to shade light on the advantages of statistical downscaling in improving the forecasting ability of air quality models. Many statistical downscaling methods in geophysics often rely on dimension reduction techniques to reduce the spatial dimension of gridded model outputs without loss of essential spatial information. In this thesis we developed a new downscaling methodology that relies on using Principal Fitted Components (PFCs) to downscale an air quality model. The main advantage of employing PFCs in downscaling relies in the fact that PFCs represent space-time variations associated with a particular location through the use of inverse regression. This means that PFCs will emphasize on location related regional information. We illustrate our proposed method by both simulation and application on ground level ozone over southeastern U.S region to downscale the Regional ChEmical TrAnsport Model (REAM). Both simulation and applications results indicate that PFC downscaling appears to yield more accurate forecasts. Moreover, we accommodate the fact that covariance matrices that are used to compute PFCs might be unstable due to the fact that they have a relatively large dimension. This issue has motivated us to regularize the covariance matrices by thresholding prior to computing the PFCs and then proceed with the downscaling using thresholded PFCs. We illustrate the modified downscaling approach by simulation and application to ground level ozone. Simulation results suggest that employing thresholded PFCs in downscaling have improved the downscaling results, however, the application results do not agree with the simulation results. Finally, we extend our PFC downscaling method to downscale an ensemble of air quality models. We propose a new two-stage dimension reduction approach to reduce the dimension of an ensemble. The proposed methodology reduces the spatial dimension in each ensemble member, and then the reduced variables are reduced further across the ensemble models. We illustrate our proposed methodology by simulation and application to downscale ground level ozone ensemble outputs in France. Both simulation and application results suggest that our proposed technique seem to show an adequate predictive performance

Occurrence of Mycotoxins and Toxigenic Fungi in Cereals and Application of Yeast Volatiles for Their Biological Control

Fungal infections in cereals lead to huge economic losses in the food and agriculture industries. This study was designed to investigate the occurrence of toxigenic fungi and their mycotoxins in marketed cereals and explore the effect of the antagonistic yeast Cyberlindnera jadinii volatiles against key toxigenic fungal strains. Aspergillus spp. were the most frequent contaminating fungi in the cereals, with an isolation frequency (Fr) of 100% in maize, followed by wheat (88.23%), rice (78.57%) and oats (14.28%). Morphological and molecular identification confirmed the presence of key toxigenic fungal strains in cereal samples, including A. carbonarius, A. flavus, A. niger, A. ochraceus and A. parasiticus. Aflatoxins (AFs) were detected in all types of tested cereal samples, with a significantly higher level in maize compared to wheat, rice, oats and breakfast cereals. Ochratoxin A (OTA) was only detected in wheat, rice and maize samples. Levels of mycotoxins in cereals were within EU permissible limits. The volatiles of Cyberlindnera jadinii significantly inhibited the growth of A. parasiticus, A. niger and P. verrucosum. The findings of this study confirm the presence of toxigenic fungi and mycotoxins in cereals within the EU permissible limits and the significant biocontrol ability of Cyberlindnera jadinii against these toxigenic fungi

Contribution of citizen science to improve knowledge on marine biodiversity in the Gulf Region

Monitoring marine biodiversity is costly and practical solutions have to be implemented to identify species and their preferred habitats, particularly in this era of rapid global change. Citizen science has proven to be effective and with high potential for monitoring efforts, and has been extensively applied to biodiversity. We have used the citizen science approach to engage the general public and stakeholders to contribute improving the current knowledge of sea snake biodiversity in Qatar and the Gulf Region. Logistic regression analysis using demographic data from interview surveys conducted in Qatar has indicated that the people having seen more sea snakes are older than 30 years and are Qatari citizens and/or fishermen from India. Of the ten species of sea snakes listed in the literature to be present in the Gulf Region, most of them have been reported for Qatar, Bahrain, United Arab Emirates and Saudi Arabia. However, the number of species present is often assumed based on their occurrence within the Arabian Gulf rather than on actual captures and appropriate identification. The creation of marine reference biological scientific collections to properly identify the species and make accurate biodiversity inventories is an urgent priority for the countries in the Gulf region. To this end, contributions by stakeholders and the general public for this study have proven to be very useful. However a larger networking with local and international scientists and stakeholders is still needed to adequately survey the country''s current biodiversity, identify research priorities and eventually provide the scientific input needed to assist biodiversity management related to renewable resource management and marine conservation in the Arabian Gulf Region

Attitudes toward and Uptake of H1N1 Vaccine among Health Care Workers during the 2009 H1N1 Pandemic

BACKGROUND: Though recommended by many and mandated by some, influenza vaccination rates among health care workers, even in pandemics, remain below optimal levels. The objective of this study was to assess vaccination uptake, attitudes, and distinguishing characteristics (including doctor-nurse differences) of health care workers who did and did not receive the pandemic H1N1 influenza vaccine in late 2009. METHODOLOGY/PRINCIPAL FINDINGS: In early 2010 we mailed a self-administered survey to 800 physicians and 800 nurses currently licensed and practicing in Minnesota. 1,073 individuals responded (cooperation rate: 69%). 85% and 62% of Minnesota physicians and nurses, respectively, reported being vaccinated. Accurately estimating the risk of vaccine side effects (OR 2.0; 95% CI 1.5-2.7), agreeing with a professional obligation to be vaccinated (OR 10.1; 95% CI 7.1-14.2), an ethical obligation to follow public health authorities' recommendations (OR 9.9; 95% CI 6.6-14.9), and laws mandating pandemic vaccination (OR 3.1; 95% CI 2.3-4.1) were all independently associated with receiving the H1N1 influenza vaccine. CONCLUSIONS/SIGNIFICANCE: While a majority of health care workers in one midwestern state reported receiving the pandemic H1N1 vaccine, physicians and nurses differed significantly in vaccination uptake. Several key attitudes and perceptions may influence health care workers' decisions regarding vaccination. These data inform how states might optimally enlist health care workers' support in achieving vaccination goals during a pandemic

Multi-ancestry genome-wide association analyses improve resolution of genes and pathways influencing lung function and chronic obstructive pulmonary disease risk

Lung-function impairment underlies chronic obstructive pulmonary disease (COPD) and predicts mortality. In the largest multi-ancestry genome-wide association meta-analysis of lung function to date, comprising 580,869 participants, we identified 1,020 independent association signals implicating 559 genes supported by ≥2 criteria from a systematic variant-to-gene mapping framework. These genes were enriched in 29 pathways. Individual variants showed heterogeneity across ancestries, age and smoking groups, and collectively as a genetic risk score showed strong association with COPD across ancestry groups. We undertook phenome-wide association studies for selected associated variants as well as trait and pathway-specific genetic risk scores to infer possible consequences of intervening in pathways underlying lung function. We highlight new putative causal variants, genes, proteins and pathways, including those targeted by existing drugs. These findings bring us closer to understanding the mechanisms underlying lung function and COPD, and should inform functional genomics experiments and potentially future COPD therapies

A rare case of marginal zone lymphoma in a 15-year old ataxia telangiectasia patient with massive bone marrow involvement and a challenging nodal diagnosis

This is a report of a very rare case of marginal zone lymphoma in a 15-years old male with Ataxia Telangiectasia. Besides being a rare diagnosis within the pediatric age group, this case exhibited a true challenge not only from diagnostic point of view but also regarding management plans. Marginal zone lymphoma is an indolent disease in which transformation is extremely rare particularly the pediatric subtype. However, there isn't enough data regarding marginal zone lymphoma in a sitting of immunodeficiency conditions had been published so far. The case described here showed some features pointing to more aggressive disease with massive bone marrow involvement and areas of focal transformation unlike the subtle pattern of infiltration that is usually seen in cases of marginal zone lymphoma. Another interesting finding in our case is the presence of a clone of CD4/CD8 double positive T-cells of moderate size (12%) with restricted expansion of Vb1 region. The significance of this clone is uncertain as it could be a transient reactive clone or a pre-malignant one. Keywords: Ataxia telangiectasia, Marginal zone lymphoma, Low grade lymphom