archives@tulane.edu / During the Deepwater Horizon (DWH) oil spill in 2010, approximately 0.5 billion liters (3.1 million barrels) of oil were released into the northern Gulf of Mexico during the largest marine oil spill in history . A significant portion of the released oil was weathered into residues by physical, photochemical, and biological processes prior to landing on 1773 km of coastline, including 754 km of marsh shoreline in Louisiana. Researchers endeavored to describe effects of oil residues in the soil on salt marsh organisms and communities. Many studies focused on two pillars of salt marsh ecology: the microbial communities through which a large portion of the salt marsh food web is connected and Spartina alterniflora, a foundational species of Gulf Coast salt marshes. In this dissertation I describe how cryptic, or difficult to observe, elements of salt marsh ecology, like microbial communities and plant genetics, respond to oil residues in the environment. Using a suite of field, growth chamber, and greenhouse experiments I show that these microbial communities are difficult to characterize and may respond to other factors more strongly than they do to oil residues. I present evidence that the plant is resilient to oil in the environment, and changes in its microbiome, but exerts a measurable influence on the biodegradation of oil residues and the microbiome in the soil. This dissertation provides a greater understanding of the complexity of the salt marsh response to an oil spill. / 1 / Stephen K. Formel

The Fisher and Seater [Fisher, M.E. and Seater, J.J., 1993. Long run neutrality and superneutrality in an ARIMA framework. American Economic Review 83, 402-415.] methodology is applied to Taylor's [Taylor, A.T., 2002. A century of purchasing power parity. Review of Economics and Statistics 84, 139-150.] data to test for purchasing power parity. Generally, the evidence is supportive of PPP. Further, FS test statistics have no size distortion problem and test power is improved with longer samples.

Soil classification in this country is based on the system proposed by Marbut in 1920 (2). This system uses eight criteria, one of which is the chemical composition of the soil horizons. Workers in the field of soil survey are depending more and more upon laboratory data to characterize and differentiate soils not only at the series level but also at higher levels of classification where it may be necessary to establish the presence or absence of critical horizons or characteristics. This was predicted by Robinson (16) when he said that laboratory analysis is needed to give "precise physical meaning to field descriptions" and that the importance of laboratory data increases as the classification of soils becomes more minute

Concentrations of potentially toxic metals in surface soils are important to investigate before building new residential areas. Prior to development of a residential area in Sundsvall, northern Sweden, it was observed that barium (Ba) concentrations in the soil at the site exceeded the guideline value of 200 mg kg-1 outlined by the Swedish Environmental Protection Agency. In this study, I aimed at determining the reason for the high Ba concentrations in the O horizon of soils from this latter area. 49 O horizon samples were collected from two separate transects (about 36 km long). A total of 43 Scots pine (Pinus sylvestris) needles were collected from both transects to determine potential Ba accumulation in plants. The O horizon and pine needle samples were analyzed using X-ray fluorescence spectrometer (XRF) to determine Ba concentrations. The total mean concentration of Ba was 426±289 mg kg-1 without any relationship to industrial sources. Barium concentrations were negatively correlated to soil organic matter (r = -0.885). Correlations between Ba, aluminum (Al), silicon (Si) and potassium (K) was r = 0.565, r = 0.486 and 0.525, a finding that suggests a strong positive coupling to elements typically found in silicate minerals. Barium concentrations in pine needle samples were below limit of detection (<LOD) suggesting that “plant pumping” via roots to the soil surface was an unlikely explanation for high concentrations in the O horizon. I conclude that the minerals in the O horizon originate from inmixing from the underlying mineral soil, therefore, high Ba concentrations in the study area is likely due to naturally occurring minerals.

This essay is an academic justification for a means of producing images explained mainly through ideas of experiential memory.

As patient access to laboratory testing outside the clinic grows, healthcare providers can expect to confront increasing questions about the utility and interpretation of consumer-initiated laboratory tests, including germline genetic testing. The aim of this study was to characterize the current marketplace diversity of what has traditionally been labeled “direct-to-consumer” genetic testing options. A horizon scan was carried out with lab tests meeting the following criteria: (1) available for purchase in U.S. between October 1, 2019, and September 30, 2021, (2) capable of using germline genetic testing to assess risk of at least one diagnosable health condition, and (3) ability to purchase without visiting a provider. We will refer to these tests as “consumer-initiated tests”. Searches were completed of the National Center for Biotechnology Information’s Genetic Test Registry, the U.S. Food and Drug Administration’s list of nucleic acid-based tests, and the International Society of Genetic Genealogy Wiki webpages. In addition, searches were performed on the three largest U.S. search engines and the three largest online retailers. In the initial search, 300 labs were identified. The websites of these laboratories were then reviewed for test offerings that matched the criteria for this study; labs without tests meeting these criteria were eliminated. Information regarding the ordering process, test characteristics, and return of results was abstracted from and validated by the webpages, sample test reports, and lab contacts through email and/or phone. In the final review of 21 laboratories that offered these tests, two primary models of testing were identified. In Model 1, a participant could pay for testing without any provider involvement. In Model 2, a participant could order a test after electing review by a company-affiliated healthcare provider. Methodologies varied from array-based genotyping to whole genome sequencing, and companies reported individual variants, complex traits, or both. Several labs also offered report customization, reporting of variants of uncertain significance, raw data downloads, and added health reports. The market for participant-initiated genetic testing for health risks continues to grow as patients seek information about their disease predisposition outside of traditional healthcare settings. Moreover, these patients can obtain raw data for reinterpretation through these testing modalities. Understanding these many test offerings can better equip primary care providers in fielding patient questions on resources such as this.

The video game industry grows bigger and bigger with each year and this growth does not seem to slow down anytime soon. With that, it's important for society and video game developers to know how this media affects the players playing the game as it's already a very big industry, with large numbers of players playing video games every day. Game designers have, and are using information horizons to influence the players in different ways, an example of this is making the player play more cautiously. There have also been previous studies that have shown that music has an impact on a player's behavior and performance while playing a video game, making players more stressed and aggressive being a conclusion for some studies. With this in mind, this study delves deeper into how music in conjunction with information horizons affects a player, playing a video game. This was done by using a controlled experiment in conjunction with a first-person shooter game, the goal of the game being clearing out a linear level of turrets using an automatic rifle. One group of test subjects played a version of the game consisting of high-tension music and information horizon in play, with another group of test subjects playing the same game without these effects in play. Data was collected in the background from each test subject's playthrough and this data was then analyzed and compared between both groups. From the data gathered it seems that music made the players play faster and more aggressively, with the information horizons effect being diminished by the music's overpowering effect. This is in line with numerous previous studies that have gotten similar end results from the effects of music in video games, with an existing research gap with regards to information horizon making the effects of the information horizon unclear.  The end results showed that group 1, playing the version of the game with high tension music and information horizon in play, had fired their weapons more, been less accurate with their shots, destroyed turrets slower, had more deaths, and played faster. These results indicate increased stress levels and aggressiveness with group 1’s test subjects.

No description available.

No description available.

The Deepwater Horizon (DWH) blowout, in the Gulf of Mexico, heavily contaminated miles of sandy beaches. Previous experience of petroleum contamination has shown that oil residues can persist in the sediments for decades. Biodegradation is the major mechanism of remediation regarding petroleum hydrocarbons. There is an urgent need to evaluate the competent indigenous microbial biomass in contaminated sediments if the risks posed by toxic oil residues, for the coastal ecosystem, are to be minimized. We report a field investigation during December 2010 and January 2011 regarding measurement of microbial activity in a sandy beach at the Bon Secour National Wildlife Refuge in Alabama. One transect of wells for sampling was installed in the beach; starting with multiport one, being most landward and thought to be least exposed to oil residue and ending with multiport four being the most seaward and exposed to the open waters of the Gulf of Mexico. Sediment samples were collected from different depths purposely chosen from above, inside, and below the oil layers for microbial analysis. Dissolved oxygen (DO) measurements were obtained and temperature was recorded while collecting the oxygen measurements. Pore water samples were collected for nutrient content and were monitored using the multiport sampling wells. Moisture content was analyzed from the sediments extracted at various depths at each well. pH and salinity were also analyzed for their contributing affect on the microbial community. Grain size distribution analyses were conducted on samples collected at all wells and at multiple depths to characterize the field study location. Results show that the bacterial biomass, as measured by Adenosine-5-triphosphate (ATP) and numbers of alkane and polycyclic aromatic hydrocarbon (PAH) degraders determined by Most Probable Number (MPN), are consistently higher in the sediment layers where oil had been detected. A very good correlation was observed among the relative abundance of bacteria in the different samples using MPN and ATP measurements. As expected, ATP based estimates of the microbial populations were two orders of magnitude higher than the alkane and PAH numbers determined by MPN, which reflect the non-cultivability of most environmental bacteria. The lower concentrations of PAH degraders than alkane degraders that were observed in this study are consistent with other studies, even though both populations are lower than in studies involving fresh oil trapped in beach or wetland sediments. PAHs (aromatics) are notoriously more resistant to biodegradation than alkanes, therefore allowing a lower number of biomass to grow using them. The overall smaller size of the bacterial numbers could be explained by the naturally occurring low-organic content of beach sand. On the other hand, this may be due to the highly weathered nature of the oil or it could reflect some other limitation. / Civil Engineering