5,811 research outputs found
The camp site beneath the Cravens House porch
Archaeological investigations beneath the porch of the Cravens house on the Lookout Mountain battlefield revealed the presence of a camp site apparently occupied by newspaper writers and artists. The camp site and its contents are described.https://scholar.utc.edu/archaeology-reports/1085/thumbnail.jp
The Influence of Service Planning Decisions on Rail Transit Success or Failure, MTI Report 08-04
Some United States metropolitan areas with rail transit systems enjoy ridership and productivity success while others do not. This study examines the experiences of 11 U.S. metropolitan areas with between one million and five million persons to better understand why some areas are successful and others are not. A particular focus is the role of service planning decisions in facilitating transit success. We find that successful transit systems are those that: 1) articulate a clear, multidestination vision for regional transit; 2) rely on rail transit as the system´s backbone; 3) recognize the importance of the non-CBD travel market; 4) encourage the use of transfers to reach a wider array of destinations; 5) recognize that rail transit alone is not enough to guarantee success; and 6) recognize the importance of serving regional destinations
Magnetized black holes and black rings in the higher dimensional dilaton gravity
In this paper we consider magnetized black holes and black rings in the
higher dimensional dilaton gravity. Our study is based on exact solutions
generated by applying a Harrison transformation to known asymptotically flat
black hole and black ring solutions in higher dimensional spacetimes. The
explicit solutions include the magnetized version of the higher dimensional
Schwarzschild-Tangherlini black holes, Myers-Perry black holes and five
dimensional (dipole) black rings. The basic physical quantities of the
magnetized objects are calculated. We also discuss some properties of the
solutions and their thermodynamics. The ultrarelativistic limits of the
magnetized solutions are briefly discussed and an explicit example is given for
the -dimensional magnetized Schwarzschild-Tangherlini black holes.Comment: LaTeX, 23 pages; v2 references and comments added, some typos
corrected;v3 minor change
Prediction-Based Learning and Processing of Event Knowledge.
Knowledge of common events is central to many aspects of cognition. Intuitively, it seems as though events are linear chains of the activities of which they are comprised. In line with this intuition, a number of theories of the temporal structure of event knowledge have posited mental representations (data structures) consisting of linear chains of activities. Competing theories focus on the hierarchical nature of event knowledge, with representations comprising ordered scenes, and chains of activities within those scenes. We present evidence that the temporal structure of events typically is not well-defined, but it is much richer and more variable both within and across events than has usually been assumed. We also present evidence that prediction-based neural network models can learn these rich and variable event structures and produce behaviors that reflect human performance. We conclude that knowledge of the temporal structure of events in the human mind emerges as a consequence of prediction-based learning
Scratch and Win! - Immediate Feedback in Physics Multiple-Choice Quizzes and Exams
Multiple-choice (MC) exams allow a large range of topics to be efficiently tested. However, the effort required to construct a good MC exam—one that tests comprehension and ability to apply knowledge, rather than rote memorization—leads to a reluctance to release solutions, thus limiting the value of the exam to students. Furthermore, students often do not spend the time necessary to review the MC portion of graded exams and may not be aware of their weaknesses with a particular topic in the syllabus.
We employed a recent innovation that provides feedback from MC questions, the Immediate Feedback Assessment Technique (IFAT), in a standard first-year Physics course. In this scheme, students respond to MC questions by scratching off a thin, opaque covering from the rectangle corresponding to their answer on a special answer card similar to a “scratch and win” lottery ticket. If their answer is correct, they uncover a star and receive full credit. In the event of a wrong answer they may reconsider their response, and scratch again to earn partial credit. Students thereby receive immediate feedback on their answers, turning the examination itself into a learning experience.
It is relatively simple to implement this form of assessment at your institution. The IFAT cards are available for purchase from Epstein Educational Enterprises. However, there are some obstacles. Since machine grading of the IFAT cards is not available, we relied on additional graduate student support for this purpose. We will also discuss the new forms of cheating attempted by students as well as difficulties we encountered constructing our tests with the IFAT system.
Based on standardized tests and comparison with a control group, we found that students improved their performance using the IFAT system, with the largest gains seen for conceptually difficult questions. Furthermore, based on an exit survey, students in the study strongly preferred this method of MC testing
Recommended from our members
Motor cortex stimulation for the enhancement of recovery from stroke: a prospective, multicenter safety study.
ObjectiveFunctional magnetic resonance imaging and transcranial magnetic stimulation studies suggest that human cortex shows evidence of neuroplasticity. Preclinical studies in rats and monkeys suggest that motor cortical stimulation can enhance plasticity and improve recovery after stroke. This study assesses the safety and preliminary efficacy of targeted subthreshold epidural cortical stimulation delivered concurrently with intensive rehabilitation therapy while using an investigational device in patients with chronic hemiparetic stroke.MethodsThis is a prospective, multicenter, and nonblinded trial randomizing patients to rehabilitation with or without cortical stimulation. Patients aged 20 to 75 years who had had an ischemic stroke at least 4 months previously causing persistent moderate weakness of the arm were included. Functional magnetic resonance imaging localized hand motor function before surgery to place an epidural cortical electrode. Both groups then underwent rehabilitation for 3 weeks after which the electrode was removed. Outcome measures were obtained at baseline, during therapy, and at 1, 4, 8, and 12 weeks postprocedure.ResultsTen patients were randomized; six patients to surgery, four to the control group. No patient deaths, neurological deterioration, or seizures occurred. There were two infections from nonprotocol-related causes. Of the eight patients completing the treatment, the stimulation plus rehabilitation group improved significantly better than controls in the Upper Extremity Fugl-Meyer (P = 0.003 overall) and the hand function score of the Stroke Impact Scale (P =0.001 overall).ConclusionThe technique of cortical stimulation to enhance stroke recovery is well tolerated and safe
Recommended from our members
Motor cortex stimulation for the enhancement of recovery from stroke: a prospective, multicenter safety study.
ObjectiveFunctional magnetic resonance imaging and transcranial magnetic stimulation studies suggest that human cortex shows evidence of neuroplasticity. Preclinical studies in rats and monkeys suggest that motor cortical stimulation can enhance plasticity and improve recovery after stroke. This study assesses the safety and preliminary efficacy of targeted subthreshold epidural cortical stimulation delivered concurrently with intensive rehabilitation therapy while using an investigational device in patients with chronic hemiparetic stroke.MethodsThis is a prospective, multicenter, and nonblinded trial randomizing patients to rehabilitation with or without cortical stimulation. Patients aged 20 to 75 years who had had an ischemic stroke at least 4 months previously causing persistent moderate weakness of the arm were included. Functional magnetic resonance imaging localized hand motor function before surgery to place an epidural cortical electrode. Both groups then underwent rehabilitation for 3 weeks after which the electrode was removed. Outcome measures were obtained at baseline, during therapy, and at 1, 4, 8, and 12 weeks postprocedure.ResultsTen patients were randomized; six patients to surgery, four to the control group. No patient deaths, neurological deterioration, or seizures occurred. There were two infections from nonprotocol-related causes. Of the eight patients completing the treatment, the stimulation plus rehabilitation group improved significantly better than controls in the Upper Extremity Fugl-Meyer (P = 0.003 overall) and the hand function score of the Stroke Impact Scale (P = 0.001 overall).ConclusionThe technique of cortical stimulation to enhance stroke recovery is well tolerated and safe
Characterization of carbonaceous aerosol during the Big Bend Regional Aerosol and Visibility Observational study
December 2001.Includes bibliographical references.The Big Bend Regional Aerosol and Visibility Observational (BRAVO) study was a four month field campaign (July-October 1999) to investigate aerosol particle properties, sources, and impacts on regional visibility in Big Bend National Park, Texas. Daily PM2.5 aerosol samples were collected on pre-fired quartz fiber filters for detailed molecular analysis of the aerosol organic carbon fraction. Aerosol black carbon concentrations during BRAVO were measured with an aethalometer. The molecular characterization of the organic carbon fraction of aerosol present during the BRAVO study was performed using gas chromatography - mass spectroscopy (GC-MS). Organic carbon concentrations on individual days were too low for a detailed analysis by GC-MS. Therefore, multi-day composite samples, selected based on common air mass trajectories and temporal proximity, were extracted and analyzed for numerous compounds, including n-alkanes, polycyclic aromatic hydrocarbons (PAH), and alkanoic acids. Low alkane Carbon Preference Indices (CPIs) during July through September reflect similar concentrations of n-alkanes containing odd and even numbers of carbon atoms and indicate that anthropogenic emissions were important contributors to carbonaceous aerosol during this period, when air masses generally were advected from the east over Texas and Mexico. In October, CPIs increased, reflecting increased influence of odd carbon numbered alkanes and suggesting a predominant biogenic aerosol influence with air masses arriving from the north and the south. Plant wax contributions to odd carbon number alkanes (C25-C33) were estimated to range between 26% and 78%, with the highest contributions occurring in October with air masses arriving from the north and south. Periods with transport from eastern Texas and northeastern Mexico had much smaller plant wax contributions. Alkanoic acids were the most abundant compound class, with CPIs that were high throughout the study. The high acid CPI suggests that the alkanoic acids may be largely biogenic in origin, a finding consistent with other studies. Caution is required in interpreting the acid CPI, however, as alkanoic acids can also be formed as secondary products of atmospheric reactions. Polycyclic aromatic hydrocarbons (P AH) were usually not found in abundance, suggesting that upwind combustion emissions were not important contributors to carbonaceous aerosol or that P AH were removed by reaction or deposition in transit. Higher P AH concentrations during one period indicated a more significant contribution from fresh combustion emissions. Molecular source tracer (hopanes for vehicle emissions, levoglucosan for wood combustion, cholesterol for meat cooking) concentrations were generally not detected. Based on analytical detection limits for these species, it was estimated that wood smoke contributed no more than 1% of the total Organic Carbon (OC) present, vehicle exhaust contributed no more than 4%, and smoke from meat cooking contributed less than 13%. The presence of other wood smoke tracer molecules, however, suggests a possibly greater influence from wood combustion and possible chemical instability of levoglucosan during multi-day transport in an acidic atmosphere. Several observations suggest that secondary production contributed significantly to BRAVO carbonaceous aerosol. Examination of ratios of aerosol organic carbon to elemental carbon indicates that secondary organic aerosol may have contributed between 45% and 90% of the total BRAVO aerosol organic carbon. High ratios of saturated/unsaturated C18 acids, an abundance of nonanoic acid, and high concentrations of 6,10,14 trimethylpentadecan-2-one (an indicator of secondary aerosol production from vegetation emissions) all support the conclusion that secondary aerosol formation was important in the region. Total black carbon (BC) concentrations ranged from below detection limit (71 ng/m3) to 267 ng/m3, averaging 129 ng/m3. Fine (< 1 ÎĽm) aerosol BC concentrations averaged 114 ng/m3, and comprised 89% of the total BC. BC concentrations correlated reasonably well with aerosol sulfate concentrations, suggesting similar source regions for these species.Funding agency: National Park Service #CA2350-97-001 T098-07, #CA2380-99-001 T001-52
Changing Kindergarten Readiness Perceptions in the Rural South
This qualitative study examined the perceptions and understandings of various stakeholders in the early childhood sector of the Southeastern United States about kindergarten readiness in response to the implementation of more rigorous academic standards in kindergarten. The study combined interviews, observations, and documents to assess experiences, expectations, and challenges in meeting the strong accountability standards imposed by accountability measures and the implementation of new standards. The qualitative analysis showed that as more rigorous standards are implemented in kindergarten, all stakeholder groups are experiencing high levels of pressure related to the testing and accountability requirements related to the standards. The study further revealed that the stakeholder groups did not share a common understanding of the level of school readiness necessary for the children to reach by first grade and that early communication with parents is necessary for a successful transition of children into the school environment. The results of the study provide insight into the perceptions and understandings of the participants as they experience the readiness process from preschool through participation in kindergarten
- …