619 research outputs found
The Effects of Cocaine Self-Administration on Cognition and Brain Metabolism
Cocaine users display a wide range of cognitive impairments and dysfunction in brain regions important for cognition. Treatment outcome is dependent on cognitive ability. It is important to understand these deficits and the underlying neurobiology. The first aim was to determine whether cocaine is sufficient to cause cognitive deficits, and if so, to determine the specificity of these cognitive deficits. Secondly, we assessed cerebral metabolic function after a drug free period. We used rhesus monkeys in a longitudinal study in which 14 animals were characterized prior to assignment to matched control (n=6) and cocaine self-administration (n=8) groups. Self-administration took place daily over nine months during which, visual and auditory contextual cues were presented. Weekly cognitive assessments were conducted following a 72 hour drug free period. We employed a stimulus discrimination/reversal task to evaluate associative learning and cognitive flexibility and the delayed match-to-sample task to assess visual working memory. In the cocaine group, we observed significant impairments in reversal performance and visual working memory after self-administration compared to controls. We examined distractibility in both groups, using brief novel distractors. Subsequently, an identical approach was used for exposure to a distractor previously associated with cocaine (experimental group), or water in the control group. In the cocaine group, stimulus discrimination was unaffected by either distractor, whereas reversal performance was disrupted by both the novel and appetitive distractors relative to baseline. Visual working memory was impaired in the cocaine group in the presence of the novel distractor. The control group’s performance was unaffected by the presentation of either distractor. Monkeys were drug free for 20 months prior to assessment of metabolic function using 18F-2-deoxyfluoro-D-glucose positron emission tomography. The cocaine group showed greater cerebellar activity than the control group while performing a visual working memory task (relative to control task). This work confirms that cocaine self-administration is sufficient to cause long lasting cognitive impairments in cognitive control, visual working memory and attention. These data also suggest that cocaine exposure alters cerebellar function, but future studies will need to be conducted to confirm that cocaine exposure is the direct cause of the metabolic differences observed
House Flies: Manure, Media, and Microbes
This study was conducted to determine if there is a difference in bacterial abundance in house flies based on sex and rearing environment (manure versus artificial media) for house flies. This is important in determining the effectiveness of the facilities where the flies are being raised. Although, previous studies have shown differences in bacterial abundance between male and female house flies, it still remains unknown whether there is a discrepancy in bacterial abundance between rearing environments in the lab. We hypothesized that there would be a greater abundance of bacteria in females than males and a greater bacterial abundance in the manure environment than the artificial media. We determined that there was no significant difference between house fly sex or the environments in which they were raised. These results are meaningful because they introduce evidence of forced interaction that could skew the bacterial counts. In the future, the results would be more telling with a larger sample size.
Mutualism: Experience of Instantaneous, Generational, and Geological Time on Heimaey Island
Iceland’s Heimaey Island’s population is approximately 4400 people (Vestmannaeyjar). The island’s main industries are fishing and tourism, which depend on the harbor on the island’s northeast side (Iceland: Westman Islands). Keeping the harbor accessible is essential to these industries. Because the harbor was almost lost during the 1973 volcanic eruption, proactive measures must be taken to protect the harbor from future eruptions.
For the purpose of this thesis, an architecture has been designed that creates a mutualistic relationship between humanity, architecture, lichens, and lava flows that is experienced over three scales of time by humanity. The concepts of instantaneous time, generational time, and geological time are reflected within the investigation. Instantaneous time is experienced in three ways. The first is visual, providing an immediate, improved view of the island for visitors. The second is through observation of the metabolic processes of lichens living on the architectural and landform surfaces. At every moment, lichens change color, activity, incrementally improving air quality, filtering excess particulates, removing carbon dioxide and adding oxygen to the atmosphere. The third is the moment of eruption, which transforms architecture, landscape and human experience in a single instant.
Generational time is human in scale - experienced through repeated experiences and memories of architecture and landform over the course of a human lifetime. Generational time is reflected in two ways. The first is in the slow growth of lichens on the lava rock and architecture. Lichens only propagate a fraction of an inch each per year, so seeing growth will take many years (Hale 79). The second is in the weathering and wear of the soft lava rock used to construct architecture, landform and pavements.
Geological time exceeds generational time. The next eruption of Eldfell will occur within the next 500 years (20-25 generations). The architecture and landform are designed to endure in place, passing between generations perhaps maintained or perhaps as ruins, and then implode when breached, thereby slowing and diverting lava flows to protect most importantly the harbor and secondarily, the town
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THE IMPACT OF THE MEDIEVAL CLIMATIC ANOMALY ON THE ARCHAEOLOGY AT EDWARDS AIR FORCE BASE
A series of severe and prolonged droughts occurred throughout the Northern Hemisphere between approximately 1150 BP to 600 BP. This phenomenon is referred to as the Medieval Climatic Anomaly and has been shown to have differentially impacted various regions of the world. Previous studies have suggested causal links between the Medieval Climatic Anomaly and observed culture change.
The goal of this study was to examine the Antelope Valley region of the Mojave Desert for evidence of impacts on human populations related to the Medieval Climatic Anomaly. To achieve this goal, a sample selection of archaeological sites was chosen from lands within Edwards Air Force Base. These sites represented occupations which occurred immediately before, during, and after the Medieval Climatic Anomaly. Site assemblages were analyzed and compared by cultural period, with cross-comparisons made of artefactual and ecofactual constituents. Site densities and areal extents were also examined and compared.
These analyses showed the emergence of trends concurrent with the introduction of the Medieval Climatic Anomaly. The data supports the hypothesis that humans who populated the Antelope Valley region of the Mojave Desert during this period may have engaged in population aggregation, with a tethered nomadism subsistence strategy. The data also shows evidence that upon the amelioration of the environment after the Medieval Climatic Anomaly, site characteristics within the region saw a significant shift.
While the evidence generated by this study does suggest a link between climatic change experienced during the Medieval Climatic Anomaly and change observed within the archaeology of the Antelope Valley, it does not suggest climate as a sole, or even primary, causal factor. Rather, the intent of this study was to identify one possible variable responsible for observed change that occurred in the region. With this in mind, the Medieval Climatic Anomaly was found to have been significant enough to have either directly or indirectly impacted the prehistoric occupants of the study region
Information Systems Curricula 2003
The goal of the study is to determine which courses are currently being offered in Information Systems (IS) undergraduate College of Business programs, to profile these curriculums, and to compare this profile to the most recent IS model curriculum--the IS 2002 Model Curriculum. Of 330 university web sites examined with potential IS undergraduate degree programs, 222 web sites were identified with complete information on program requirements. The resulting profile matches the IS 2002 Model in eight out of eleven courses with two Model courses being represented by two profile courses each and one profile course not matching a Model course.
Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli
Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyldimethylammonium chloride (pDADMAC). The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm) of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%). Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process
Impact of Community Pharmacists on Management of Cancer Chemotherapy and the Resulting Side Effects
The severe side effects of chemotherapy negatively affect quality of life and may limit the amount of life-saving drug delivered to patients with cancer. These adverse events can be difficult to manage and evidence-based guidelines are lacking. Insufficient supportive care can amplify common side effects, such as chemotherapy-induced nausea and vomiting (CINV), myelosuppression, alopecia, gastrointestinal effects and neuropathy. Therefore, it is important to recognize the most commonly dispensed chemotherapy agents and the side effects that accompany them. Community pharmacists, as easily accessible health care professionals, can provide valuable supportive care to help manage potentially debilitating side effects. However, a major limitation when managing side effects secondary to chemotherapy is the limited access to patient information in most community pharmacies. By allowing community pharmacists increased access to patient health records using technology, limitations experienced in practice can be averted and quality care provided
Overview of Instructional Technology Used in the Education of Occupational Therapy Students: A Survey Study
The purpose of this study was to explore the type of instructional technology (IT) master’s degree level occupational therapy educational programs routinely use as a part of their lecture- and laboratory-based instruction. Surveying the administrators of 121 graduate occupational therapy programs in the United States, we found that the majority of the respondents identified their program as using IT in some form for lecture-based courses, with less inclusion of IT for laboratory-based courses. Hybrid instruction, with the majority of the content being delivered face-to-face and the remainder via online, were the trends among the respondents. The findings also indicated that the respondents’ programs avoid certain IT, including synchronous online chat rooms or instant messaging, digital image collections, blogs or online journaling, Wikis, and audio/video podcasting. Few of the respondents said their programs had made a significant leap into implementing a larger online presence with instructional technology
Human pathogen shown to cause disease in the threatened elkhorn coral Acropora palmata
Coral reefs are in severe decline. Infections by the human pathogen Serratia marcescens have contributed to precipitous losses in the common Caribbean elkhorn coral, Acropora palmata, culminating in its listing under the United States Endangered Species Act. During a 2003 outbreak of this coral disease, called acroporid serratiosis (APS), a unique strain of the pathogen, Serratia marcescens strain PDR60, was identified from diseased A. palmata, human wastewater, the non-host coral Siderastrea siderea and the corallivorous snail Coralliophila abbreviata. In order to examine humans as a source and other marine invertebrates as vectors and/or reservoirs of the APS pathogen, challenge experiments were conducted with A. palmata maintained in closed aquaria to determine infectivity of strain PDR60 from reef and wastewater sources. Strain PDR60 from wastewater and diseased A. palmata caused disease signs in elkhorn coral in as little as four and five days, respectively, demonstrating that wastewater is a definitive source of APS and identifying human strain PDR60 as a coral pathogen through fulfillment of Koch\u27s postulates. A. palmata inoculated with strain PDR60 from C. abbreviata showed limited virulence, with one of three inoculated fragments developing APS signs within 13 days. Strain PDR60 from non-host coral S. siderea showed a delayed pathogenic effect, with disease signs developing within an average of 20 days. These results suggest that C. abbreviata and non-host corals may function as reservoirs or vectors of the APS pathogen. Our results provide the first example of a marine “reverse zoonosis” involving the transmission of a human pathogen (S. marcescens) to a marine invertebrate (A. palmata). These findings underscore the interaction between public health practices and environmental health indices such as coral reef survival
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