98 research outputs found
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Patterns of sediment accumulation in Watts Bar Reservoir based on sup 137 Cesium
No full textThe US Department of Energy has recently undertaken an environmental restoration program designed to achieve remediation of hazardous materials released from the Oak Ridge Reservation (ORR). The distribution of {sup 137}Cs was investigated in sediments from Watts Barr Reservoir and the Clinch River as a possible marker for other contaminants released from the ORR. We have performed additional analyses on the data gathered for this study to investigate possible relationships between {sup 137}Cs accumulation and reservoir characteristics. We found that {sup 137}Cs deposition correlates with sedimentation rate, and soft mud layers of cores have higher {sup 137}Cs levels than sandy mud or eroded soils. No correlation was found with water depth, distance from shore or distance from release source, but it is important to note the data were not collected to test for these effects. We estimate Watts Barr Reservoir contains 267 Ci of {sup 137}Cs, with 7% of this total in the top 16 cm of sediment, and potentially available for biological accumulation. 2 refs. (MHB
Modeling the use of the Adaptive Joint C4ISR Node in a tactical environment
No full textThe Adaptive Joint Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) Node (AJCN) is a new C4ISR system with four functional capabilities: communications, signal intelligence (SIGINT), electronic warfare (EW) and Information Operations. This thesis evaluates the first three capabilities of the AJCN: communications, SIGINT and EW. Simulation is used as a time- and cost-effective way to model the AJCN's capabilities. Eleven communications and combat effectiveness MOE are used to evaluate the AJCN's performance. Point of Attack 2, a tactical simulation with an extensive database is used to replicate the AJCN and UA operations. Results of the analysis include: 1) the AJCN significantly increased friendly detection of enemy forces; 2) the AJCN significantly decreased average message transmittal time and the number of failed messages; 3) the AJCN increased the friendly force's capability to jam and intercept enemy messages.Approved for public release; distribution is unlimited.http://archive.org/details/modelinguseofajc10945187
Burning for northern mountain ungulates: effects of prescribed fire
No full text"Prescribed fire is used as a management tool to enhance ungulate habitats. In northeastern British Columbia, up to 7,800 ha are burned annually. Yet relatively few studies have quantified the role of fire on plant and animal response, and whether it enables species such as Stone's sheep (Ovis dalli stonei) and elk (Cervus elaphus). In the Muskwa-Kechika Management Area, we examined the response of Stone's sheep and elk to seasonal changes in forage quantity and quality over an elevation gradient in areas recently burned by prescribed fires versus unburned control areas. We monitored vegetation and fecal-pellet transects at a fine scale and used Landsat imagery, survey flights, and telemetry locations at a landscape scale. One year after burning, forage digestibility and rates of forage growth were higher on burned than unburned areas. At both scales, Stone's sheep and elk always used burns more than unburned areas in winter. Stone's sheep and elk appeared to partition their use of the landscape through topography and land cover. Increased use of burned areas suggests that prescribed fires enhanced habitat value for grazing ungulates at least in the short term. By altering animal distributions, however, use of prescribed fire has the potential to change predator-prey interactions."Peer reviewe
Listeria monocytogenes prevalence in cold smoked fish within the validity period of product
No full textMaģistra darba praktiskā daļa izstrādāta Pārtikas drošības, dzīvnieku veselības un vides zinātniskajā institūtā „BIOR”. Darba mērķis bija novērtēt Listeria monocytogenes izplatību auksti kūpinātu (a/k) zivju produktos to derīguma termiņa ietvaros¬. Lai izvērtētu risku, kāds varētu rasties lietojot šos pārtikas produktus, tika noteikta L. monocytogenes klātbūtne un skaits (KVV/g). Darba gaitā tika iegādāti 37 dažādi a/k zivju produkti, no katra zivju produkta pērkot divus iepakojumus, trīs dažādās partijās, atkārtojumu veikšanai. No pārbaudītajiem 222 paraugiem maksimāli pieļaujamo robežvērtību (100 KVV/g) pārsniedza viens paraugs, savukārt L. monocytogenes izplatība a/k vakuumētās zivīs bija 5,6% un a/k neiepakotās zivīs 9,4%. Vakuumā iepakotās zivīs L. monocytogenes izolāti uzrādīja 1/2a-3a serotipu, taču neiepakotās zivīs – 1/2a-3a, 4ab-ab-4d-4e un 1/2b-3b-7.Master's thesis was developed at Institute of Food Safety, Animal Health and Environment "BIOR". The aim was to assess the prevalence of Listeria monocytogenes in cold-smoked fish products within the validity period. The presence and the number of colony forming units (CFU/g) of L. monocytogenes was determined for risk evaluation. Author bought 37 different cold-smoked fish products, from each fish product— two products in three different batches. In the 222 tested samples, the maximum limit (100 CFU/g) exceeded one sample. In vacuum-packed cold-smoked fish products L. monocytogenes was present in 5.6%, and in non-packed cold-smoked fish— 9.4%. In vacuum-packed fish L. monocytogenes isolates had 1/2a-3a serotype, but from non-packed fish— 1/2a-3a, 4ab-ab-4d-4e and 1/2b-3b-7
Perception, history, and science: coherence or disparity in the timing of the Little Ice Age maximum in southeast Iceland?
No full textIn Iceland, studies that integrate local perceptions about the landscape with scientific evidence of change have been few. This article presents a case study from southeast Iceland that has two main objectives. Firstly, ethnographic data is used to explore the human dimension of the Little Ice Age through perceptions of landscape and climatic change and to describe the impacts that these changes had on life and livelihood. Secondly, the paper critically assesses the coherence of the scientific record regarding the Little Ice Age glacial maximum with evidence gained from the ethnographic survey and the local historical record. Although climatic deterioration from the seventeenth through nineteenth centuries ultimately affected farming viability, it was the interplay of climate with concomitant cultural and socio-economic factors that ensured effective strategies were emplaced to preserve life and livelihood in southeast Iceland. Furthermore, despite different trajectories of perception emanating from either the scientific or the local points of view, data from all sources are strongly coherent and point to a Little Ice Age maximum during the late eighteenth to early nineteenth centuries. This study also illustrates that sensitive landscapes can ‘store memories’ through the cumulative accumulation of disturbances during periods of climatic variability, eventually reaching a critical threshold and inducing landscape instability, such as occurred during the nineteenth century
Relative Seed Preferences of the Deer Mouse (\u3ci\u3ePeromyscus maniculatus\u3c/i\u3e): Field and Laboratory Observations
No full textField and laboratory experiments were conducted during the 1989 growing season to examine the seed preferences of two geographically distinct deer mouse (Peromyscus maniculatus) populations. Of the ten seed species offered, balsam root (Balsamorhiza sagittata (Pursh)Nutt.), Indian rice grass (Oryzopsis hymenoides (R. & S.) Ricker), millet (Panicurn miliaceum L.), and antelope bitterbrush (Purshia tridentata (Pursh) DC.) seeds were more preferred than big sagebrush (Artemisia tridentata Nutt.), yarrow (Achillea millefolium L.), shadscale (Atriplex confertifolia (Torr. & Frems.) Watts.), wild rye (Elymus cinereus Scribn. & Merr.), western wheat grass (Pascopyrum smithii (Rydb.) Love), and green needle grass (Stipa viridula Trin). The relationship between preference and nutritional attributes of the seeds was examined. Preference was significantly correlated with nine nutritional seed qualities. Preferences were inversely correlated with acid soluble ash, calories/gram, non-nutritive matter, protein, solvent extract, and structural carbohydrate. Preferences were positively correlated with cell contents, moisture, and soluble carbohydrate. The correlations were in agreement with Frank\u27s (1988a,b) observations that desert rodents choose seeds high in free water or seeds with nutrients that have high net metabolic water yields. Potential sources of preference variation were examined as the seed selection data were collected. Field preferences varied significantly between two microhabitats and between two times during the growing season. Preferences also varied between the two populations. Under laboratory conditions, preferences were different among individuals but not for one individual over a series of trials. Comparison of laboratory and field preferences indicated that laboratory preferences did not always reflect field preferences. Variability in the data implied that extrapolation of seed preferences from the population level to species level and from laboratory individuals to field populations may not always be valid
Shifting attention in viewer- and object-based reference frames after unilateral brain injury
No full textThe aims of the present study were to investigate the respective roles that object- and viewer-based reference frames play in reorienting visual attention, and to assess their influence after unilateral brain injury. To do so, we studied 16 right hemisphere injured (RHI) and 13 left hemisphere injured (LHI) patients. We used a cueing design that manipulates the location of cues and targets relative to a display comprised of two rectangles (i.e., objects). Unlike previous studies with patients, we presented all cues at midline rather than in the left or right visual fields. Thus, in the critical conditions in which targets were presented laterally, reorienting of attention was always from a midline cue. Performance was measured for lateralized target detection as a function of viewer-based (contra- and ipsilesional sides) and object-based (requiring reorienting within or between objects) reference frames. As expected, contralesional detection was slower than ipsilesional detection for the patients. More importantly, objects influenced target detection differently in the contralesional and ipsilesional fields. Contralesionally, reorienting to a target within the cued object took longer than reorienting to a target in the same location but in the uncued object. This finding is consistent with object-based neglect. Ipsilesionally, the means were in the opposite direction. Furthermore, no significant difference was found in object-based influences between the patient groups (RHI vs. LHI). These findings are discussed in the context of reference frames used in reorienting attention for target detection
Altered anterior visual system development following early monocular enucleation
No full textPurpose
Retinoblastoma is a rare eye cancer that generally occurs before 5 years of age and often results in enucleation (surgical removal) of the cancerous eye. In the present study, we sought to determine the consequences of early monocular enucleation on the morphological development of the anterior visual pathway including the optic chiasm and lateral geniculate nucleus.
Methods
A group of adults who had one eye enucleated early in life due to retinoblastoma was compared to binocularly intact controls. Although structural changes have previously been reported in late enucleation, we also collected data from one late enucleated participant to compare to our early enucleated participants. Measurements of the optic nerves, optic chiasm, optic tracts and lateral geniculate nuclei were evaluated from T1 weighted and proton density weighted images collected from each participant.
Results
The early monocular enucleation group exhibited overall degeneration of the anterior visual system compared to controls. Surprisingly, however, optic tract diameter and geniculate volume decreases were less severe contralateral to the remaining eye. Consistent with previous research, the late enucleated participant showed no asymmetry and significantly larger volume decreases in both geniculate nuclei compared to controls.
Conclusions
The novel finding of an asymmetry in morphology of the anterior visual system following long-term survival from early monocular enucleation indicates altered postnatal visual development. Possible mechanisms behind this altered development include recruitment of deafferented cells by crossing nasal fibres and/or geniculate cell retention via feedback from primary visual cortex. These data highlight the importance of balanced binocular input during postnatal maturation for typical anterior visual system morphology.This research was funded by the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, and the Canadian National Institute for the Blind. Publication was made possible by the York University Libraries' Open Access Author Fund
Influence of prescribed fire on Stone's sheep and Rocky Mountain elk: Forage characteristics and resource separation.
No full textFor over 30 years prescribed fire has been used as a management tool to enhance ungulate habitat in northeastern British Columbia (BC), where up to 7,800 ha are burned annually. Yet relatively few studies have quantified the role of fire on both plant and animal response, and whether it enables competition between focal grazing species such as Stone's sheep (Ovis dalli stonei) and elk (Cervus elaphus). Seven prescribed burns (150-1,000 ha) were implemented in the spring of 2010 and 2011 in the Besa-Prophet area of northern BC. I examined the response of Stone's sheep and elk to seasonal changes in forage quantity and quality by elevation in treatment versus control areas. I monitored vegetation and fecal pellet transects at a fine scale and used Landsat imagery, survey flights and GPS telemetry at a landscape scale. By one year after burning, forage digestibility and rates of forage growth were higher on burned than unburned areas. At both scales Stone's sheep and elk always used burns more than control areas in winter. Stone's sheep and elk appeared to partition their use of the landscape through topography and land cover. Increased use of burned areas suggests that prescribed fire enhanced habitat value for grazing ungulates in the short-term. By altering animal distributions, however, the use of prescribed fire has the potential to change complex predator-prey interactions in northern BC. --Leaf ii.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b189085
Animal assisted crisis response and creating connections: a practical guide for implementing therapy dogs into a victim services policing environment
No full textThis project was created to address the needs of police based victim services units as they implement a therapy dog program into police detachments. Taking the form of a manual, this project examines the many considerations of implementing a program that has very little precedent in Canada and no precedent at all within the Royal Canadian Mounted Police (RCMP). The manual is broken down into distinct sections with headings and sub-headings that address different aspects of each component listed. The main content is factual and experiential in nature and will lead the reader through the considerations of implementation as well as offering examples of the program in practice. The project looks at the historical precedence of animal assisted therapy and explores its challenges, findings and successes while also discovering the unexpected benefit of the therapy dogs' presence within the detachment itself and how this soft approach to grounding helps clients, officers and victim services workers alike. --Leaf ii.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b200682
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