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Search Results: 1 - 10 of 1818 matches for " Tracy Butler "
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The hazards of lack of co-registration of ictal brain SPECT with MRI: A case report of sinusitis mimicking a brainstem seizure focus
Tracy Butler, Lawrence J Hirsch, Jan Claassen
BMC Medical Physics , 2004, DOI: 10.1186/1471-2385-4-2
Abstract: A young woman with encephalitis and refractory seizures underwent brain SPECT during a period of frequent seizure-like episodes, and during a seizure-free period. A focal area of increased radiotracer uptake present only when she was experiencing frequent seizure-like episodes was originally localized to the brainstem, but with later computerized co-registration of SPECT to MRI, was found to lie outside the brain, in the region of the sphenoid sinus.Low-resolution SPECT images present difficulties in interpretation, which can be overcome through co-registration to higher-resolution structural images.Radiotracers used for brain single photon emitted computed tomography (SPECT) pass the blood-brain barrier and bind intracellularly on their first pass through the circulation, providing a "snapshot" of cerebral perfusion at a particular timepoint. When injected during a focal epileptic seizure, an area of significantly increased radiotracer uptake typically corresponds to the region of maximal abnormal activity, often the seizure focus. This ictal pattern of cerebral blood flow can be compared to an interictal/baseline pattern obtained when the patient is not having a seizure, to provide unique information about the nature and location of a patient's epileptic focus, which can be used to guide therapy [See [1] for a review of the use of SPECT in epilepsy].A previously-healthy young woman developed behavioral changes followed by seizures and refractory status epilepticus. She was diagnosed with encephalitis and treated with antiviral and multiple antiepileptic agents. She required nasotracheal intubation and mechanical ventilation for respiratory support. She experienced persistent episodes of facial twitching resembling seizures. These episodes were not however associated with an ictal EEG pattern on continuous video/EEG monitoring. To clarify the nature of these episodes, 99mTc-HMPAO was injected during a period of frequent twitching. Brain SPECT showed a prominent foc
Providing a Technology Edge for Liberal Arts Students
Tracy Chao,Terry Butler,Peter Ryan
Journal of Information Technology Education : Research , 2003,
Abstract:
The impact of social isolation on HPA axis function, anxiety-like behaviors, and ethanol drinking
Tracy R. Butler,Jeffrey L. Weiner
Frontiers in Integrative Neuroscience , 2014, DOI: 10.3389/fnint.2013.00102
Abstract: Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis is often observed in alcoholics and humans subjected to early life stress, and animal models of ethanol (EtOH) dependence. We examined HPA axis function in a rodent model of early life stress that engenders increases in behavioral and neurobiological risk factors of alcoholism. Long-Evans male rats were group housed (GH) or socially isolated (SI) for 6 weeks during adolescence. We examined the corticosterone (CORT) response to stress with and without dexamethasone (DEX) and anxiety-like behaviors. Following the DEX suppression test and behavioral assays, half of the cohort engaged in 6 weeks of EtOH drinking in a homecage, two-bottle choice intermittent access model. A subset of the cohort was not exposed to EtOH, but was used for electrophysiological measurement of glutamatergic synaptic plasticity in the basolateral amygdala (BLA). Correlational analyses examined relationships between measures of CORT, anxiety-like behaviors, and EtOH intake/preference. With DEX pre-treatment, SI rats failed to suppress CORT in response to an acute stress; GH rats showed a significant suppression. In SI rats, there was a significant negative correlation between baseline CORT and elevated plus maze open arm time, as well as significant positive correlations between baseline CORT and both EtOH intake and preference. No significant relationships between baseline CORT and behavioral measures were observed in GH rats. Glutamatergic plasticity in the BLA was similar in magnitude between GH and SI rats, and was not altered by exogenous application of CORT. These data suggest that HPA axis function is affected by SI, and this is related to antecedent anxiety-like behavior and may predispose for future EtOH self-administration. Relationships between HPA axis function, anxiety, and EtOH measures in SI rats further strengthens the utility of this paradigm in modeling vulnerability for affective disorders and alcoholism.
Zero forcing for inertia sets
Steve Butler,Jason Grout,H. Tracy Hall
Mathematics , 2012,
Abstract: Zero forcing is a combinatorial game played on a graph with a goal of turning all of the vertices of the graph black while having to use as few "unforced" moves as possible. This leads to a parameter known as the zero forcing number which can be used to give an upper bound for the maximum nullity of a matrix associated with the graph. We introduce a new variation on the zero forcing game which can be used to give an upper bound for the maximum nullity of a matrix associated with a graph that has $q$ negative eigenvalues. This gives some limits to the number of positive eigenvalues that such a graph can have and so can be used to form lower bounds for the inertia set of a graph.
Impact of the Invasive Brown Marmorated Stink Bug, Halyomorpha halys (St?l), in Mid-Atlantic Tree Fruit Orchards in the United States: Case Studies of Commercial Management
Tracy C. Leskey,Brent D. Short,Bryan R. Butler,Starker E. Wright
Psyche , 2012, DOI: 10.1155/2012/535062
Abstract: Four commercial orchards in the mid-Atlantic region of the United States were surveyed weekly in 2010 and 2011 for the presence of brown marmorated stink bug and the injury caused to both apple and peaches. Among tested sampling techniques, pyramid traps baited with the aggregation pheromone of Plautia stali Scott, methyl-(2E,4E,6Z)-decatrienoate, yielded the most brown marmorated stink bug adults and nymphs, followed by visual observations. Brown marmorated stink bugs began to feed on apples and peaches soon after fruit set and continued to feed on fruit throughout the growing season. Injury to apple was relatively inconsequential until after mid-June, whereas feeding on peaches resulted in immediate economic injury as the surface became distorted, dented, discolored, and the flesh beneath turned brown. Significantly more apples were injured and with greater severity in 2010 than in 2011. Likewise, percent injury on the exterior portion of each apple plot was significantly greater than injury reported from the interior in both years. Growers increased the number of insecticide applications nearly 4-fold from 2010 to 2011. In addition to the increased number of targeted insecticide applications, growers also reduced the interval between treatments in 2011. A metric was created to compare the relative intensity of each grower's commercial management program between seasons and amongst each other. 1. Introduction The brown marmorated stink bug, Halyomorpha halys (St?l), is an invasive stink bug native to Japan, Korea, China, and Taiwan [1], now well established throughout the mid-Atlantic region of the United States. Evidence of established populations in Switzerland [2] and Canada [3] has also been reported. Brown marmorated stink bug is an extremely polyphagous species, and a pest of many crops in Asia [4] including tree fruit, vegetables, shade trees, and leguminous crops with specific mention of apple, cherry, peach, and pear [4, 5]. Surveys conducted in the United States identified a number of tree fruit hosts for brown marmorated stink bug including apple, plum, peach, pear, and cherry [5–7]. In 2010, populations of this invasive species increased dramatically, causing widespread injury to many crops throughout the mid-Atlantic region [8]. Tree fruit, in particular, was hit hard with some growers losing entire crops of stone fruit. Among apple growers, losses were totaled in excess of 37 million dollars in the region [9]. Within the United States, native stink bugs generally have been classified as secondary pests of tree fruit orchards and have
A New Method of Estimating the Asset Rate of Return  [PDF]
Moawia Alghalith, Tracy Polius
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.11001
Abstract: We present a new consumption-based method of estimating the asset rate of return.
Measured and Perceived Physical Fitness, Intention, and Self-Reported Physical Activity in Adolescence  [PDF]
Timo Jaakkola, Tracy Washington
Advances in Physical Education (APE) , 2011, DOI: 10.4236/ape.2011.12004
Abstract: Objective: The aim of this study was to investigate the associations among measured physical fitness, perceived fitness, intention towards future physical activity and self-reported physical activity through junior high school years. Methods: Study participants included 122 Finnish students who were 13 years old during Grade 7. The sample was comprised of 80 girls and 42 boys from 3 junior high schools (Grades 7-9). During the autumn semester of Grade 7, students completed fitness tests and a questionnaire analyzing self-perception of their physical fitness. The questionnaire delivered at Grade 8 included intention towards future physical activity. At Grade 9 students’ self-reported physical activity levels. Results: Structural Equation Modelling revealed an indirect path from physical fitness to self-reported physical activity via perceived physical fitness and intention towards future physical activity. The model also demonstrated a correlation between perceived physical fitness and physical activity. Squared multiple correlations revealed that perceived physical fitness explained 33 % of the actual physical fitness. Conclusions: The results of this study highlight the role of physical and cognitive variables in the process of adoption of physical activity in adolescence.
Collision Resolution MAC Protocols for Wireless Ad Hoc Networks  [PDF]
Xinhua Yang, Tracy Camp
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.51003
Abstract:

In wireless ad hoc networks, nodes cooperatively form a network without any infrastructure such as a BS/AP (base station or access point). The widely-used contention-based MAC protocol, IEEE 802.11b, is inefficient in multi-hop networks due to the hidden and exposed terminal problems. The most popular schedule-based MAC protocol, TDMA (time division multiple access), is difficult to implement in an ad hoc network due to the lack of infrastructure. The contribution of this paper is to provide the community novel and efficient MAC (medium access control) protocols (i.e., a collision resolution protocol) for a wireless ad hoc network without a centralized infrastructure. We propose two new MAC protocols (one distributed algorithm and one cluster-based algorithm) that use a collision resolution scheme for a network with a single BS/AP. We first compare the performance of our distributed algorithm with our cluster-based algorithm. Then, we compare our algorithm that performs better (i.e., our cluster-based algorithm) to TDMA in a two-hop network. The simulation results illustrate that our cluster-based algorithm provides higher throughput and lower delay than TDMA in a two-hop network.


Research Findings Using Mindfulness-Based Interventions for Chronic Pain  [PDF]
Tracy L. Skaer
Pain Studies and Treatment (PST) , 2015, DOI: 10.4236/pst.2015.34005
Abstract: Chronic pain is a complex condition that is very detrimental to physical and psychological wellbeing. It carries a significant level of disability and economic burden. Pain patients frequently experience comorbid mental illness (e.g. depression, anxiety, PTSD, insomnia) and often require psychotherapeutic interventions in addition to medication management. Mindfulness-based interventions (MBIs) have emerged as a means to treat several chronic conditions (e.g. chronic pain, depression, anxiety, substance abuse, stress, insomnia). The objective of this review is to evaluate the current research on the use of MBIs in chronic pain managment. Although there are several controlled trials on the use of MBIs in chronic pain management, only a few studies were found that demonstrated significant effects on pain intensity, quality of life, as well as physical and psychological functioning. Therefore, the current evidence is mixed and there are insufficient data to definitively confirm the full impact of the use of MBIs in chronic pain conditions such as fibromyalgia, chronic low back pain, rheumatoid arthritis, and chronic musculoskeletal pain. The lack of compelling evidence at this time signals a demand for higher quality investigations in this area. Research examining MBIs and concomitant CBT may be of great value in order to synergize and strengthen patient outcomes.
Understanding the Consequences of Property Rights Mismatches: a Case Study of New Zealand's Marine Resources
Tracy Yandle
Ecology and Society , 2007,
Abstract: Within fisheries and natural resource management literature, there is considerable discussion about the key roles that property rights can play in building biologically and socially sustainable resource management regimes. A key point of agreement is that secure long-term property rights provide an incentive for resource users to manage the resource sustainably. However, property rights mismatches create ambiguity and conflict in resource use. Though the term mismatches is usually associated with problems in matching temporal and spatial resource characteristics with institutional characteristics, I expand it here to include problems that can arise when property rights are incompletely defined or incompletely distributed. Property rights mismatches are particularly likely to occur over marine resources, for which multiple types of resource and resource user can be engaged and managed under a variety of regulatory regimes. I used New Zealand's marine resources to examine the causes and consequences of these property rights mismatches. New Zealand is particularly interesting because its property-rights-based commercial fishing regime, in the form of individual transferable quotas, has attracted considerable positive attention. However, my review of the marine natural resource management regime from a broader property rights perspective highlights a series of problems caused by property rights mismatches, including competition for resources among commercial, customary, and recreational fishers; spatial conflict among many marine resource users; and conflicting incentives and objectives for the management of resources over time. The use of a property rights perspective also highlights some potential solutions such as the layering of institutional arrangements and the improvement of how property rights are defined to encourage long-term sustainability.
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