Science.gov

Sample records for exam mlc reserved

  1. Megalencephalic Leukoencephalopathy with Subcortical Cysts (MLC)

    MedlinePlus

    ... new treatments for the disease. Are there other names for Megalencephalic Leukoencephalopathy with subcortical Cysts (MLC)? Other names for Megalencephalic Leukoencephalopathy with subcortical Cysts (MLC) include: ...

  2. Knockdown of MLC1 in primary astrocytes causes cell vacuolation: a MLC disease cell model

    PubMed Central

    Duarri, Anna; de Heredia, Miguel Lopez; Capdevila-Nortes, Xavier; Ridder, Margreet C.; Montolio, Marisol; López-Hernández, Tania; Boor, Ilja; Lien, Chun-Fu; Hagemann, Tracy; Messing, Albee; Gorecki, Dariusz C.; Scheper, Gert C.; Martínez, Albert; Nunes, Virginia; van der Knaap, Marjo S.; Estévez, Raúl

    2013-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of leukodystrophy, in the majority of cases caused by mutations in the MLC1 gene. MRI from MLC patients shows diffuse cerebral white matter signal abnormality and swelling, with evidence of increased water content. Histopathology in a MLC patient shows vacuolation of myelin, which causes the cerebral white matter swelling. MLC1 protein is expressed in astrocytic processes that are part of blood- and cerebrospinal fluid-brain barriers. We aimed to create an astrocyte cell model of MLC disease. The characterization of rat astrocyte cultures revealed MLC1 localization in cell-cell contacts, which contain other proteins described typically in tight and adherent junctions. MLC1 localization in these contacts was demonstrated to depend on the actin cytoskeleton; it was not altered when disrupting the microtubule or the GFAP networks. In human tissues, MLC1 and the protein Zonula Occludens 1 (ZO-1), which is linked to the actin cytoskeleton, co-localized by EM immunostaining and were specifically co-immunoprecipitated. To create an MLC cell model, knockdown of MLC1 in primary astrocytes was performed. Reduction of MLC1 expression resulted in the appearance of intracellular vacuoles. This vacuolation was reversed by the co-expression of human MLC1. Reexamination of a human brain biopsy from an MLC patient revealed that vacuoles were also consistently present in astrocytic processes. Thus, vacuolation of astrocytes is also a hallmark of MLC disease. PMID:21440627

  3. Testicular self-exam

    MedlinePlus

    Screening - testicular cancer - self-exam; Testicular cancer - screening - self-exam ... A testicular self-exam is done to check for testicular cancer . Testicles have blood vessels and other structures that can make the exam ...

  4. Slit-lamp exam

    MedlinePlus

    ... to light for a few hours after the exam if dilating drops are used. ... The slit lamp exam may detect many diseases of the eye, including: Clouding of the lens of the eye ( cataract ) Injury to the ...

  5. Exams: The Secret Ingredients

    ERIC Educational Resources Information Center

    DiJulio, Betsy

    2012-01-01

    This year, many high-school teachers in the district where the author teaches experienced exam anxiety because midterms--as they had come to know and love them--were no more. For a variety of reasons, the semester exam schedule looked very different. More to the point is the new philosophy about exam content and format that underpinned the…

  6. Diabetes eye exams

    MedlinePlus

    ... catch problems early if you get regular eye exams. ... diabetes checks your eyes, you need an eye exam every 1 to 2 years by an eye ... problems with your vision. Many can do screening exams for damage from diabetes. Once you have eye ...

  7. Exams: The Secret Ingredients

    ERIC Educational Resources Information Center

    DiJulio, Betsy

    2012-01-01

    This year, many high-school teachers in the district where the author teaches experienced exam anxiety because midterms--as they had come to know and love them--were no more. For a variety of reasons, the semester exam schedule looked very different. More to the point is the new philosophy about exam content and format that underpinned the

  8. Challenges When Introducing Electronic Exam

    ERIC Educational Resources Information Center

    Kuikka, Matti; Kitola, Markus; Laakso, Mikko-Jussi

    2014-01-01

    Time pressures often necessitate the use of more efficient exam tools, such as electronic exams (e-exams), instead of traditional paper exams. However, teachers may face challenges when introducing e-exams in a higher education context. This paper describes what kinds of challenges teachers may face when introducing e-exams, based on experiences…

  9. Challenges When Introducing Electronic Exam

    ERIC Educational Resources Information Center

    Kuikka, Matti; Kitola, Markus; Laakso, Mikko-Jussi

    2014-01-01

    Time pressures often necessitate the use of more efficient exam tools, such as electronic exams (e-exams), instead of traditional paper exams. However, teachers may face challenges when introducing e-exams in a higher education context. This paper describes what kinds of challenges teachers may face when introducing e-exams, based on experiences

  10. Exam preparation learning

    NASA Astrophysics Data System (ADS)

    Fakcharoenphol, Witat

    This thesis investigates student learning through practice exams. A series of experiments were conducted using a web-based platform that provided students with an organized structure to study past exam problems. We establish the learning obtained from doing these practice exams (Chapter 1) and then manipulate the feedback mechanisms (Chapter 2 and 4) and duration of the treatment (Chapter 3). The results show that all students benefit from practice exams and worked out solution feedback. However, investing more resources in this learning tool might not result in better learning gains. A comparison between experiments suggests that, beyond the quality of the practice exams and solution feedback, motivation and learning goals may be crucial to enhancing student learning during exam preparation.

  11. Radio frequency noise from an MLC: a feasibility study of the use of an MLC for linac-MR systems.

    PubMed

    Lamey, M; Yun, J; Burke, B; Rathee, S; Fallone, B G

    2010-02-21

    Currently several groups are actively researching the integration of a megavoltage teletherapy unit with magnetic resonance (MR) imaging for real-time image-guided radiotherapy. The use of a multileaf collimator (MLC) for intensity-modulated radiotherapy for linac-MR units must be investigated. The MLC itself will likely reside in the fringe field of the MR and the motors will produce radio frequency (RF) noise. The RF noise power spectral density from a Varian 52-leaf MLC motor, a Varian Millennium MLC motor and a brushless fan motor has been measured as a function of the applied magnetic field using a near field probe set. For the Varian 52-leaf MLC system, the RF noise produced by 13 of 52 motors is studied as a function of distance from the MLC. Data are reported in the frequency range suitable for 0.2-1.5 T linac-MR systems. Below 40 MHz the Millennium MLC motor tested showed more noise than the Varian 52-leaf motor or the brushless fan motor. The brushless motor showed a small dependence on the applied magnetic field. Images of a phantom were taken by the prototype linac-MR system with the MLC placed in close proximity to the magnet. Several orientations of the MLC in both shielded and non-shielded configurations were studied. For the case of a non-shielded MLC and associated cables, the signal-to-noise ratio (SNR) was reduced when 13 of 52 MLC leaves were moved during imaging. When the MLC and associated cables were shielded, the measured SNR of the images with 13 MLC leaves moving was experimentally the same as the SNR of the stationary MLC image. When the MLC and cables are shielded, subtraction images acquired with and without MLC motion contains no systematic signal. This study illustrates that the small RF noise produced by functioning MLC motors can be effectively shielded to avoid SNR degradation. A functioning MLC can be incorporated into a linac-MR unit. PMID:20090187

  12. Radio frequency noise from an MLC: a feasibility study of the use of an MLC for linac-MR systems

    PubMed Central

    Lamey, M; Yun, J; Burke, B; Rathee, S; Fallone, B G

    2010-01-01

    Currently several groups are actively researching the integration of a megavoltage teletherapy unit with magnetic resonance (MR) imaging for real-time image-guided radiotherapy. The use of a multileaf collimator (MLC) for intensity-modulated radiotherapy for linac-MR units must be investigated. The MLC itself will likely reside in the fringe field of the MR and the motors will produce radio frequency (RF) noise. The RF noise power spectral density from a Varian 52-leaf MLC motor, a Varian Millennium MLC motor and a brushless fan motor has been measured as a function of the applied magnetic field using a near field probe set. For the Varian 52-leaf MLC system, the RF noise produced by 13 of 52 motors is studied as a function of distance from the MLC. Data are reported in the frequency range suitable for 0.2–1.5 T linac-MR systems. Below 40 MHz the Millennium MLC motor tested showed more noise than the Varian 52-leaf motor or the brushless fan motor. The brushless motor showed a small dependence on the applied magnetic field. Images of a phantom were taken by the prototype linac-MR system with the MLC placed in close proximity to the magnet. Several orientations of the MLC in both shielded and non-shielded configurations were studied. For the case of a non-shielded MLC and associated cables, the signal-to-noise ratio (SNR) was reduced when 13 of 52 MLC leaves were moved during imaging. When the MLC and associated cables were shielded, the measured SNR of the images with 13 MLC leaves moving was experimentally the same as the SNR of the stationary MLC image. When the MLC and cables are shielded, subtraction images acquired with and without MLC motion contains no systematic signal. This study illustrates that the small RF noise produced by functioning MLC motors can be effectively shielded to avoid SNR degradation. A functioning MLC can be incorporated into a linac-MR unit. PMID:20090187

  13. Examining Exam Reviews: A Comparison of Exam Scores and Attitudes

    ERIC Educational Resources Information Center

    Hackathorn, Jana; Cornell, Kathryn; Garczynski, Amy M.; Solomon, Erin D.; Blankmeyer, Katheryn E.; Tennial, Rachel E.

    2012-01-01

    Instructors commonly use exam reviews to help students prepare for exams and to increase student success. The current study compared the effects of traditional, trivia, and practice test-based exam reviews on actual exam scores, as well as students' attitudes toward each review. Findings suggested that students' exam scores were significantly…

  14. Tolerances on MLC leaf position accuracy for IMRT delivery with a dynamic MLC.

    PubMed

    Rangel, Alejandra; Dunscombe, Peter

    2009-07-01

    The objective determination of performance standards for radiation therapy equipment requires, ideally, establishing the quantitative relationship between performance deviations and clinical outcome or some acceptable surrogate. In this simulation study the authors analyzed the dosimetric impact of random (leaf by leaf) and systematic (entire leaf bank) errors in the position of the MLC leaves on seven clinical prostate and seven clinical head and neck IMRT plans delivered using a dynamic MLC. In-house software was developed to incorporate normally distributed errors of up to +/- 2 mm in individual leaf position or systematic errors (+/- 1 and +/- 0.5 mm in all leaves of both leaf banks or +1 mm in one bank only) into the 14 plans, thus simulating treatment delivery using a suboptimally performing MLC. The dosimetric consequences of suboptimal MLC performance were quantified using the equivalent uniform doses (EUDs) of the clinical target volumes and important organs at risk (OARs). The deviation of the EUDs of the selected structures as the performance of the MLC deteriorated was used as the objective surrogate of clinical outcome. Random errors of 2 mm resulted in negligible changes for all structures of interest in both sites. In contrast, systematic errors can lead to potentially significant dosimetric changes that may compromise clinical outcome. If a 2% change in EUD of the target and 2 Gy for the OARs were adopted as acceptable levels of deviation in dose due to MLC effects alone, then systematic errors in leaf position will need to be limited to 0.3 mm. This study provides guidance, based on a dosimetric surrogate of clinical outcome, for the development of one component, leaf position accuracy of performance standards for multileaf collimators. PMID:19673226

  15. Identification of novel MLC1 mutations in Chinese patients with megalencephalic leukoencephalopathy with subcortical cysts (MLC).

    PubMed

    Wang, Jingmin; Shang, Jing; Wu, Ye; Gu, Qiang; Xiong, Hui; Ding, Changhong; Wang, Liwen; Gao, Zhijie; Wu, Xiru; Jiang, Yuwu

    2011-02-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal, recessively inherited disease caused by mutations in the MLC1 gene. Most of the previously published studies have been carried out in ethnic populations other than the Chinese. In this study, the analysis of clinical features and MLC1 mutation screening were performed in 13 Chinese patients for the first time. A total of 10 MLC1 mutations were identified in these patients, including five novel missense mutations (c.65G>A, p.R22Q; c.95C>T, p.A32V; c.218G>A, p.G73E; c.823G>A, p.A275T; c.832T>C, p.Y278H), one novel splicing mutation (c.772-1G>C in IVS9-1), one novel small deletion (c.907_930del, p.V303_L310del), one known nonsense mutation (c.593delCTCA, p.Y198X) and two known missense mutations (c.206C>T, p.S69L; c.353C>T, p.T118M). Mutation c.772-1G>C in IVS9-1, accounting for 27.3% (3/11) of the total number of genetically confirmed patients found in this study, is thus a putative hot-spot mutation in the present study group. The existence of a unique MLC1 mutation spectrum in Chinese MLC patients was shown. A systemic study to assess the mutation spectra in different populations should be undertaken. PMID:21160490

  16. My Favorite Exam Question

    NASA Astrophysics Data System (ADS)

    Styer, Dan

    2015-12-01

    My favorite exam question comes from the final exam in an introductory mechanics course: A rolling 31 ton railroad boxcar collides with a stationary flatcar. The coupling mechanism activates so the cars latch together and roll down the track attached. Of the initial kinetic energy, 38% dissipates as heat, sound, vibrations, mechanical deformation, and so forth. How much does the flatcar weigh?

  17. Skin self-exam

    MedlinePlus

    ... your skin for any unusual growths or skin changes. A skin self-exam helps find many skin problems early. Finding ... Look for several things when doing a skin self-exam. New skin markings: Bumps Moles Blemishes Changes in color Moles that have changed in: Size ...

  18. Breast self-exam

    MedlinePlus

    A breast self-exam is a check-up a woman does at home to look for changes or problems in the breast tissue. ... not agree about the benefits of breast self-exams in finding breast cancer or saving lives. Talk ...

  19. My Favorite Exam Question

    ERIC Educational Resources Information Center

    Styer, Dan

    2015-01-01

    My favorite exam question comes from the final exam in an introductory mechanics course: "A rolling 31 ton railroad boxcar collides with a stationary flatcar. The coupling mechanism activates so the cars latch together and roll down the track attached. Of the initial kinetic energy, 38% dissipates as heat, sound, vibrations, mechanical

  20. My Favorite Exam Question

    ERIC Educational Resources Information Center

    Styer, Dan

    2015-01-01

    My favorite exam question comes from the final exam in an introductory mechanics course: "A rolling 31 ton railroad boxcar collides with a stationary flatcar. The coupling mechanism activates so the cars latch together and roll down the track attached. Of the initial kinetic energy, 38% dissipates as heat, sound, vibrations, mechanical…

  1. Physical exam frequency

    MedlinePlus

    How often you need a physical exam; Health maintenance visit; Health screening; Checkup ... All adults should visit their health care provider from time to time, even if they are healthy. The purpose of these visits is to: Screen for diseases ...

  2. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J.

    1980-01-01

    Provides exam questions and solutions for a problem in amplification sequence of reactions, and a problem in applying group theory techniques and making spectral assignments and structural determination by qualitative arguments in the bonding in metal complexes. (CS)

  3. The Mathematics and Computer Science Learning Center (MLC).

    ERIC Educational Resources Information Center

    Abraham, Solomon T.

    The Mathematics and Computer Science Learning Center (MLC) was established in the Department of Mathematics at North Carolina Central University during the fall semester of the 1982-83 academic year. The initial operations of the MLC were supported by grants to the University from the Burroughs-Wellcome Company and the Kenan Charitable Trust Fund.…

  4. Stop "Going Over" Exams! The Multiple Benefits of Team Exams

    ERIC Educational Resources Information Center

    Stark, Gary

    2006-01-01

    This article describes the use of team exams as a means of postexam feedback and explains the benefits of their use. Team exams are a simple procedure for those who use exams in their classrooms. Team exams can be a valuable experiential exercise in management classes but offer educational benefits in any class. Among the benefits of team exams…

  5. Neuroprotective and neuroproliferative activities of NeuroAid (MLC601, MLC901), a Chinese medicine, in vitro and in vivo.

    PubMed

    Heurteaux, C; Gandin, C; Borsotto, M; Widmann, C; Brau, F; Lhuillier, M; Onteniente, B; Lazdunski, M

    2010-06-01

    Although stroke remains a leading cause of death and adult disability, numerous recent failures in clinical stroke trials have led to some pessimism in the field. Interestingly, NeuroAid (MLC601), a traditional medicine, particularly used in China, South East Asia and Middle East has been reported to have beneficial effects in patients, particularly in post-stroke complications. Here, we demonstrate in a rodent model of focal ischemia that NeuroAid II (MLC901) pre- and post-treatments up to 3 h after stroke improve survival, protect the brain from the ischemic injury and drastically decrease functional deficits. MLC601 and MLC901 also prevent neuronal death in an in vitro model of excitotoxicity using primary cultures of cortical neurons exposed to glutamate. In addition, MLC601/MLC901 treatments were shown to induce neurogenesis in rodent and human cells, promote cell proliferation as well as neurite outgrowth and stimulate the development of a dense axonal and dendritic network. MLC601 and MLC901 clearly represent a very interesting strategy for stroke treatment at different stages of the disease. PMID:20064536

  6. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J., Ed.

    1978-01-01

    Two exam questions are presented. One suitable for advanced undergraduate or beginning graduate courses in organic chemistry, is on equivalent expressions for the description of several pericyclic reactions. The second, for general chemistry students, asks for an estimation of the rate of decay of a million-year-old Uranium-238 sample. (BB)

  7. Exam 2 Strategy

    ERIC Educational Resources Information Center

    Cummings, Richard G.; Gruber, Robert A.

    2006-01-01

    After students take their first exam in an accounting course, tax accounting and intermediate accounting in this case, their reactions to their test scores may be varied. This is their first major assessment of how they have performed in the class. The students in the class near the high end of the grading scale are going to be satisfied with…

  8. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Ramette, R. W.

    1988-01-01

    Describes a take-home exam story problem based on stoichiometry. Requires the student to determine the percentage of phosphoric acid in a large container of nitric acid if a man fell into it. Provides assumptions, clues, and an acceptable solution. (MVL)

  9. An experimental comparison of conventional two-bank and novel four-bank dynamic MLC tracking

    NASA Astrophysics Data System (ADS)

    Davies, G. A.; Clowes, P.; McQuaid, D.; Evans, P. M.; Webb, S.; Poludniowski, G.

    2013-03-01

    The AccuLeaf mMLC featuring four multileaf-collimator (MLC) banks has been used for the first time for an experimental comparison of conventional two-bank with novel four-bank dynamic MLC tracking of a two-dimensional sinusoidal respiratory motion. This comparison was performed for a square aperture, and for three conformal treatment apertures from clinical radiotherapy lung cancer patients. The system latency of this prototype tracking system was evaluated and found to be 1.0 s and the frequency at which MLC positions could be updated, 1 Hz, and therefore accurate MLC tracking of irregular patient motion would be difficult with the system in its current form. The MLC leaf velocity required for two-bank-MLC and four-bank-MLC tracking was evaluated for the apertures studied and a substantial decrease was found in the maximum MLC velocity required when four-banks were used for tracking rather than two. A dosimetric comparison of the two techniques was also performed and minimal difference was found between two-bank-MLC and four-bank-MLC tracking. The use of four MLC banks for dynamic MLC tracking is shown to be potentially advantageous for increasing the delivery efficiency compared with two-bank-MLC tracking where difficulties are encountered if large leaf shifts are required to track motion perpendicular to the direction of leaf travel.

  10. Preparing Students for the AP Psychology Exam

    ERIC Educational Resources Information Center

    Whitlock, Kristin

    2013-01-01

    The Advanced Placement Psychology exam is one of the fastest growing exams offered by the College Board. The average percent of change in the number of students taking this exam over the past five years is 12.4%. With 238,962 students taking the exam in 2013, the AP Psychology exam is the sixth largest exam, surpassing AP Biology and AP World…

  11. Preparing Students for the AP Psychology Exam

    ERIC Educational Resources Information Center

    Whitlock, Kristin

    2013-01-01

    The Advanced Placement Psychology exam is one of the fastest growing exams offered by the College Board. The average percent of change in the number of students taking this exam over the past five years is 12.4%. With 238,962 students taking the exam in 2013, the AP Psychology exam is the sixth largest exam, surpassing AP Biology and AP World

  12. NOTE: Reducing the number of segments in unidirectional MLC segmentations

    NASA Astrophysics Data System (ADS)

    Mellado, X.; Cruz, S.; Artacho, J. M.; Canellas, M.

    2010-02-01

    In intensity-modulated radiation therapy (IMRT), fluence matrices obtained from a treatment planning system are usually delivered by a linear accelerator equipped with a multileaf collimator (MLC). A segmentation method is needed for decomposing these fluence matrices into segments suitable for the MLC, and the number of segments used is an important factor for treatment time. In this work, an algorithm for reduction of the number of segments (NS) is presented for unidirectional segmentations, where there is no backtracking of the MLC leaves. It uses a geometrical representation of the segmentation output for searching the key values in a fluence matrix that complicate its decomposition. The NS reduction is achieved by performing minor modifications in these values, under the conditions of avoiding substantial modifications of the dose-volume histogram, and does not increase in average the total number of monitor units delivered. The proposed method was tested using two clinical cases planned with the PCRT 3D® treatment planning system.

  13. MLC1 is associated with the Dystrophin-Glycoprotein Complex at astrocytic endfeet

    PubMed Central

    Boor, Ilja; Nagtegaal, Machiel; Kamphorst, Wouter; van der Valk, Paul; Pronk, Jan C.; van Horssen, Jack; Dinopoulos, Argirios; Bove, Kevin E.; Pascual-Castroviejo, Ignacio; Muntoni, Francesco; Estévez, Raúl; Scheper, Gert C.

    2007-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a progressive cerebral white matter disease with onset in childhood, caused by mutations in the MLC1 gene. MLC1 is a protein with unknown function that is mainly expressed in the brain in astrocytic endfeet at the blood–brain and cerebrospinal fluid–brain barriers. It shares its localization at astrocytic endfeet with the dystrophin-associated glycoprotein complex (DGC). The objective of the present study was to investigate the possible association of MLC1 with the DGC. To test this hypothesis, (co)-localization of DGC-proteins and MLC1 was analyzed by immunohistochemical stainings in gliotic brain tissue from a patient with multiple sclerosis, in glioblastoma tissue and in brain tissue from an MLC patient. In control tissue, a direct protein interaction was tested by immunoprecipitation. Results revealed that MLC1 is co-localized with DGC-proteins in gliotic brain tissue. We demonstrated that both MLC1 and aquaporin-4, a member of the DGC, were redistributed in glioblastoma cells. In MLC brain tissue, we showed absence of MLC1 and altered expression of several DGC-proteins. We demonstrated a direct protein interaction between MLC1 and Kir4.1. From these results we conclude that MLC1 is associated with the DGC at astrocytic endfeet. PMID:17628813

  14. X-Ray Exam: Pelvis

    MedlinePlus

    ... Caring for Your Child All About Food Allergies X-Ray Exam: Pelvis KidsHealth > For Parents > X-Ray Exam: Pelvis Print A A A Text Size ... español Radiografía: pelvis What It Is A pelvis X-ray is a safe and painless test that uses ...

  15. X-Ray Exam: Ankle

    MedlinePlus

    ... Child All About Food Allergies X-Ray Exam: Ankle KidsHealth > For Parents > X-Ray Exam: Ankle Print A A A Text Size What's in ... en español Radiografía: tobillo What It Is An ankle X-ray is a safe and painless test ...

  16. Fast regional readout CMOS Image Sensor for dynamic MLC tracking

    NASA Astrophysics Data System (ADS)

    Zin, H.; Harris, E.; Osmond, J.; Evans, P.

    2014-03-01

    Advanced radiotherapy techniques such as volumetric modulated arc therapy (VMAT) require verification of the complex beam delivery including tracking of multileaf collimators (MLC) and monitoring the dose rate. This work explores the feasibility of a prototype Complementary metal-oxide semiconductor Image Sensor (CIS) for tracking these complex treatments by utilising fast, region of interest (ROI) read out functionality. An automatic edge tracking algorithm was used to locate the MLC leaves edges moving at various speeds (from a moving triangle field shape) and imaged with various sensor frame rates. The CIS demonstrates successful edge detection of the dynamic MLC motion within accuracy of 1.0 mm. This demonstrates the feasibility of the sensor to verify treatment delivery involving dynamic MLC up to ~400 frames per second (equivalent to the linac pulse rate), which is superior to any current techniques such as using electronic portal imaging devices (EPID). CIS provides the basis to an essential real-time verification tool, useful in accessing accurate delivery of complex high energy radiation to the tumour and ultimately to achieve better cure rates for cancer patients.

  17. An MLC calibration method using a detector array

    PubMed Central

    Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray

    2009-01-01

    Purpose: The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. Methods: The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Corporation, Melbourne, FL). To calibrate the MLC bank, its backup jaw is positioned at the central axis and the opposing jaw is retracted to create a half-beam configuration. The position of the backup jaws field edge is then measured with the array to obtain what is termed the radiation defined reference line. The positions of the individual leaf ends relative to this reference line are then inferred by the detector response in the leaf end penumbra. Iteratively adjusting and remeasuring the leaf end positions to within specifications completes the calibration. Using the backup jaw as a reference for the leaf end positions is based on three assumptions: (1) The leading edge of an MLC leaf bank is parallel to its backup jaw’s leading edge, (2) the backup jaw position is reproducible, and (3) the measured radiation field edge created by each leaf end is representative of that leaf’s position. Data from an electronic portal imaging device (EPID) were used in a similar analysis to check the results obtained with the array. Results: The relative leaf end positions measured with the array differed from those measured with the EPID by an average of 0.11 ±0.09 mm per leaf. The maximum leaf positional change measured with the Profiler 2 over a 3 month period was 0.51 mm. A leaf positional accuracy of ±0.4 mm is easily attainable through the iterative calibration process. The method requires an average of 40 min to measure both leaf banks. Conclusions: This work demonstrates that the Profiler 2 is an effective tool for efficient and quantitative MLC quality assurance and calibration. PMID:19928080

  18. An MLC calibration method using a detector array

    SciTech Connect

    Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray

    2009-10-15

    Purpose: The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. Methods: The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Corporation, Melbourne, FL). To calibrate the MLC bank, its backup jaw is positioned at the central axis and the opposing jaw is retracted to create a half-beam configuration. The position of the backup jaws field edge is then measured with the array to obtain what is termed the radiation defined reference line. The positions of the individual leaf ends relative to this reference line are then inferred by the detector response in the leaf end penumbra. Iteratively adjusting and remeasuring the leaf end positions to within specifications completes the calibration. Using the backup jaw as a reference for the leaf end positions is based on three assumptions: (1) The leading edge of an MLC leaf bank is parallel to its backup jaw's leading edge, (2) the backup jaw position is reproducible, and (3) the measured radiation field edge created by each leaf end is representative of that leaf's position. Data from an electronic portal imaging device (EPID) were used in a similar analysis to check the results obtained with the array. Results: The relative leaf end positions measured with the array differed from those measured with the EPID by an average of 0.11 {+-}0.09 mm per leaf. The maximum leaf positional change measured with the Profiler 2 over a 3 month period was 0.51 mm. A leaf positional accuracy of {+-}0.4 mm is easily attainable through the iterative calibration process. The method requires an average of 40 min to measure both leaf banks. Conclusions: This work demonstrates that the Profiler 2 is an effective tool for efficient and quantitative MLC quality assurance and calibration.

  19. MLC1 protein: a likely link between leukodystrophies and brain channelopathies

    PubMed Central

    Brignone, Maria S.; Lanciotti, Angela; Camerini, Serena; De Nuccio, Chiara; Petrucci, Tamara C.; Visentin, Sergio; Ambrosini, Elena

    2015-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLCs) disease is a rare inherited, autosomal recessive form of childhood-onset spongiform leukodystrophy characterized by macrocephaly, deterioration of motor functions, epileptic seizures and mental decline. Brain edema, subcortical fluid cysts, myelin and astrocyte vacuolation are the histopathological hallmarks of MLC. Mutations in either the MLC1 gene (>75% of patients) or the GlialCAM gene (<20% of patients) are responsible for the disease. Recently, the GlialCAM adhesion protein was found essential for the membrane expression and function of the chloride channel ClC-2 indicating MLC disease caused by mutation in GlialCAM as the first channelopathy among leukodystrophies. On the contrary, the function of MLC1 protein, which binds GlialCAM, its functional relationship with ClC-2 and the molecular mechanisms underlying MLC1 mutation-induced functional defects are not fully understood yet. The human MLC1 gene encodes a 377-amino acid membrane protein with eight predicted transmembrane domains which shows very low homology with voltage-dependent potassium (K+) channel subunits. The high expression of MLC1 in brain astrocytes contacting blood vessels and meninges and brain alterations observed in MLC patients have led to hypothesize a role for MLC1 in the regulation of ion and water homeostasis. Recent studies have shown that MLC1 establishes structural and/or functional interactions with several ion/water channels and transporters and ion channel accessory proteins, and that these interactions are affected by MLC1 mutations causing MLC. Here, we review data on MLC1 functional properties obtained in in vitro and in vivo models and discuss evidence linking the effects of MLC1 mutations to brain channelopathies. PMID:25883547

  20. Dynamic tumor tracking using the Elekta Agility MLC

    SciTech Connect

    Fast, Martin F. Nill, Simeon Bedford, James L.; Oelfke, Uwe

    2014-11-01

    Purpose: To evaluate the performance of the Elekta Agility multileaf collimator (MLC) for dynamic real-time tumor tracking. Methods: The authors have developed a new control software which interfaces to the Agility MLC to dynamically program the movement of individual leaves, the dynamic leaf guides (DLGs), and the Y collimators (“jaws”) based on the actual target trajectory. A motion platform was used to perform dynamic tracking experiments with sinusoidal trajectories. The actual target positions reported by the motion platform at 20, 30, or 40 Hz were used as shift vectors for the MLC in beams-eye-view. The system latency of the MLC (i.e., the average latency comprising target device reporting latencies and MLC adjustment latency) and the geometric tracking accuracy were extracted from a sequence of MV portal images acquired during irradiation for the following treatment scenarios: leaf-only motion, jaw + leaf motion, and DLG + leaf motion. Results: The portal imager measurements indicated a clear dependence of the system latency on the target position reporting frequency. Deducting the effect of the target frequency, the leaf adjustment latency was measured to be 38 ± 3 ms for a maximum target speed v of 13 mm/s. The jaw + leaf adjustment latency was 53 ± 3 at a similar speed. The system latency at a target position frequency of 30 Hz was in the range of 56–61 ms for the leaves (v ≤ 31 mm/s), 71–78 ms for the jaw + leaf motion (v ≤ 25 mm/s), and 58–72 ms for the DLG + leaf motion (v ≤ 59 mm/s). The tracking accuracy showed a similar dependency on the target position frequency and the maximum target speed. For the leaves, the root-mean-squared error (RMSE) was between 0.6–1.5 mm depending on the maximum target speed. For the jaw + leaf (DLG + leaf) motion, the RMSE was between 0.7–1.5 mm (1.9–3.4 mm). Conclusions: The authors have measured the latency and geometric accuracy of the Agility MLC, facilitating its future use for clinical tracking applications.

  1. Cytology exam of pleural fluid

    MedlinePlus

    Pleural fluid cytology ... A cytology exam is used to look for cancer and precancerous cells. It may also be done for other ... a cancerous tumor . This test most often detects: Breast cancer Lymphoma Lung cancer Ovarian cancer Stomach cancer

  2. Developing On-line Exams.

    ERIC Educational Resources Information Center

    Hartsell, Taralynn S.; Yuen, Steve Chi-Yin

    2003-01-01

    Discusses advantages and limitations of online exams, describes available software tools for creating computer-based tests (CGI, JavaScript, commercial programs, course authoring tools), and offers suggestions for implementation. (JOW)

  3. EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS)

    EPA Science Inventory

    The Exposure Analysis Modeling System (EXAMS), first published in 1982 (EPA-600/3-82-023), provides interactive computer software for formulating aquatic ecosystem models and rapidly evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals--pesti...

  4. RhoA-mediated MLC2 regulates actin dynamics for cytokinesis in meiosis.

    PubMed

    Duan, Xing; Liu, Jun; Zhu, Cheng-Cheng; Wang, Qiao-Chu; Cui, Xiang-Shun; Kim, Nam-Hyung; Xiong, Bo; Sun, Shao-Chen

    2016-02-01

    During oocyte meiosis, the bipolar spindle forms in the central cytoplasm and then migrates to the cortex. Subsequently, the oocyte extrudes the polar body through two successive asymmetric divisions, which are regulated primarily by actin filaments. Myosin light chain2 (MLC2) phosphorylation plays pivotal roles in smooth muscle contraction, stress fiber formation, cell motility and cytokinesis. However, whether MLC2 phosphorylation participates in the oocyte polarization and asymmetric division has not been clarified. The present study investigated the expression and functions of MLC2 during mouse oocyte meiosis. Our result showed that p-MLC2 was localized in the oocyte cortex, with a thickened cap above the chromosomes. Meanwhile, p-MLC2 was also localized in the poles of spindle. Disruption of MLC2 activity by MLC2 knock down (KD) caused the failure of polar body extrusion. Immunofluorescent staining showed that a large proportion of oocytes arrested in telophase stage and failed to undergo cytokinesis after culturing for 12hours. In the meantime, actin filament staining at oocyte membrane and cytoplasm were reduced in MLC2KD oocytes. Finally, we found that the phosphorylation of MLC2 protein levels was decreased after disruption of RhoA activity. Above all, our data indicated that the RhoA-mediated MLC2 regulates the actin organization for cytokinesis during mouse oocyte maturation. PMID:26701676

  5. MLC dosimetric characteristics for small field and IMRT applications.

    PubMed

    Bayouth, J E; Morrill, S M

    2003-09-01

    The objective of this work was to measure the performance characteristics of a double-focus multileaf collimator (MLC) for intensity modulated radiation therapy (IMRT), specifically the variation in penumbra and leakage for narrow fields as a function of field position over a 20x27 cm space available for segmented MLC IMRT. Measurements were made with 6 MV x rays through a MLC containing 29 leaf pairs (27 pairs of 1 cm width), and EDR2 film at 10 cm depth in solid water at 100 cm SAD. Films were digitized with 0.17 mm resolution and converted to dose. Interleaf and intraleaf transmission were measured along 11 vertical profile locations. Leaf-end transmission was measured along horizontal profiles for each of 9 different leaf abutments, traveling over a 20 cm range. In-plane penumbra measurements were made through a single leaf retracted, for 7 different leaves. Cross-plane penumbra (leaf-end) measurements were made for all 27 leaf pairs, where the 1 cm field width was placed in 11 different off-axis positions (20 cm range). Interleaf leakage (range 1.0%-1.5%), intraleaf transmission (range 0.6%-0.8%), and leaf-end transmission (range 0.8%-2.7%) were consistent for all leaf pairs at a given abutment position. The penumbra for these 1-cm-wide fields was measured to be 0.36 cm+/-0.03 cm for 99% of the measurements. In conclusion, the penumbra and leakage of the double-focus MLC were remarkably consistent for the range of leaf positions studied, producing dosimetric characteristics that are well suited for IMRT segments where opposing leaf pairs are often separated by 10 mm or less. PMID:14528977

  6. Thermal and electrostrictive expansion characteristics of MLC (Multilayer Ceramic) capacitors

    SciTech Connect

    Chanchani, R.; Hall, C.A.

    1991-01-01

    We have measured by strain gauge technique, in-plane thermal expansivity (coefficient of thermal expansion) as a function of temperature and electrostrictive expansion as a function of applied DC voltage for ceramic capacitors with X7R, NPO and N1500 dielectrics. Multilayer Ceramic (MLC) capacitor materials from two commercial suppliers were evaluated. Thermal expansivities of these materials were compared to polyimide-quartz boards and alumina ceramic substrates. 4 refs., 9 figs., 1 tab.

  7. Student Exam Creation as a Learning Tool

    ERIC Educational Resources Information Center

    Brink, Jan; Capps, Emerson; Sutko, Al

    2004-01-01

    The purpose of this study was to determine if there is a relationship between: 1) comprehensiveness of student developed model tests and final exam score, 2) the quality of student developed model tests and answer keys combined, and final exam score, and 3) student developed model test similarity to instructor final exam and final exam score.…

  8. Physics Exams That Promote Collaborative Learning

    ERIC Educational Resources Information Center

    Wieman, Carl E.; Rieger, Georg W.; Heiner, Cynthia E.

    2014-01-01

    The two-stage exam is a relatively simple way to introduce collaborative learning and formative assessment into an exam. Their use is rapidly growing in the physics department at the University of British Columbia, as both students and faculty find them rewarding. In a two-stage exam students first complete and turn in the exam individually, and…

  9. Are Online Exams an Invitation to Cheat?

    ERIC Educational Resources Information Center

    Harmon, Oskar R.; Lambrinos, James; Kennedy, Peter, Ed.

    2008-01-01

    In this study, the authors use data from two online courses in principles of economics to estimate a model that predicts exam scores from independent variables of student characteristics. In one course, the final exam was proctored, and in the other course, the final exam was not proctored. In both courses, the first three exams were unproctored.…

  10. TomoTherapy MLC verification using exit detector data

    SciTech Connect

    Chen Quan; Westerly, David; Fang Zhenyu; Sheng, Ke; Chen Yu

    2012-01-15

    Purpose: Treatment delivery verification (DV) is important in the field of intensity modulated radiation therapy (IMRT). While IMRT and image guided radiation therapy (IGRT), allow us to create more conformal plans and enables the use of tighter margins, an erroneously executed plan can have detrimental effects on the treatment outcome. The purpose of this study is to develop a DV technique to verify TomoTherapy's multileaf collimator (MLC) using the onboard mega-voltage CT detectors. Methods: The proposed DV method uses temporal changes in the MVCT detector signal to predict actual leaf open times delivered on the treatment machine. Penumbra and scattered radiation effects may produce confounding results when determining leaf open times from the raw detector data. To reduce the impact of the effects, an iterative, Richardson-Lucy (R-L) deconvolution algorithm is applied. Optical sensors installed on each MLC leaf are used to verify the accuracy of the DV technique. The robustness of the DV technique is examined by introducing different attenuation materials in the beam. Additionally, the DV technique has been used to investigate several clinical plans which failed to pass delivery quality assurance (DQA) and was successful in identifying MLC timing discrepancies as the root cause. Results: The leaf open time extracted from the exit detector showed good agreement with the optical sensors under a variety of conditions. Detector-measured leaf open times agreed with optical sensor data to within 0.2 ms, and 99% of the results agreed within 8.5 ms. These results changed little when attenuation was added in the beam. For the clinical plans failing DQA, the dose calculated from reconstructed leaf open times played an instrumental role in discovering the root-cause of the problem. Throughout the retrospective study, it is found that the reconstructed dose always agrees with measured doses to within 1%. Conclusions: The exit detectors in the TomoTherapy treatment systems can provide valuable information about MLC behavior during delivery. A technique to estimate the TomoTherapy binary MLC leaf open time from exit detector signals is described. This technique is shown to be both robust and accurate for delivery verification.

  11. Small field dosimetric characterization of a new 160-leaf MLC.

    PubMed

    Cranmer-Sargison, G; Liu, P Z Y; Weston, S; Suchowerska, N; Thwaites, D I

    2013-10-21

    The goal of this work was to perform a 6 MV small field characterization of the new Agility 160-leaf multi-leaf collimator (MLC) from Elekta. This included profile measurement analysis and central axis relative output measurements using various diode detectors and an air-core fiber optic scintillation dosimeter (FOD). Data was acquired at a depth of 10.0 cm for field sizes of 1.0, 0.9, 0.8, 0.7, 0.6 and 0.5 cm. Three experimental data sets, comprised of five readings, were made for both the relative output and profile measurements. Average detector-specific output ratios (OR[overline](f(clin))(det))) were calculated with respect to a field size of 3.0 cm and small field replacement correction factors (k(f(clin),f(msr))(Q(clin),Q(msr))) derived for the diodes using the scintillation dosimeter readings as the baseline. The standard experimental uncertainty on OR[overline](f(clin))(det)) was calculated at a 90% confidence interval and the coefficient of variation (CV) used to characterize the detector-specific measurement precision. The positional accuracy of the collimation system was also investigated by analyzing the repeated profile measurements and field width constancy investigated as a function of collimator rotation. For comparison the output and profile measurements were repeated using the Elekta 80-leaf MLCi2 on a beam matched linac at 6 MV. The measured OR[overline](f(clin))(det)) varied as a function of detector and MLC design. At the smallest field size the standard experimental uncertainty on OR[overline](f(clin))(det)) was consistent across all detectors at approximately 0.5% and 1.0% for Agility and MLCi2 collimators respectively. The CV associated with the FOD measurements were greater than that of the diodes but did not translate into increased measurement uncertainty. At the smallest field size, the diode detector correction factors were approximately 2% greater for MLCi2 than that required for the Agility. Profile data revealed the Agility MLC to have a greater positional reproducibility than both the MLCi2 and the linac diaphragms (jaws), as also reflected in the experimental uncertainties on OR[overline](f(clin))(det)). The relative output, profile widths and associated uncertainties were all found to differ between the two MLC systems investigated, as were the field size specific diode detector replacement correction factors. The data also clearly showed that the Agility 160-leaf MLC performs to a tighter positional tolerance than the MLCi2. PMID:24077128

  12. Molecular pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts: mutations in MLC1 cause folding defects

    PubMed Central

    Duarri, Anna; Teijido, Oscar; López-Hernández, Tania; Scheper, Gert C.; Barriere, Herve; Boor, Ilja; Aguado, Fernando; Zorzano, Antonio; Palacín, Manuel; Martínez, Albert; Lukacs, Gergely L.; van der Knaap, Marjo S.; Nunes, Virginia; Estévez, Raúl

    2008-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of leukodystrophy, most often caused by mutations in the MLC1 gene. MLC1 is an oligomeric plasma membrane (PM) protein of unknown function expressed mainly in glial cells and neurons. Most disease-causing missense mutations dramatically reduced the total and PM MLC1 expression levels in Xenopus oocytes and mammalian cells. The impaired expression of the mutants was verified in primary cultures of rat astrocytes, as well as human monocytes, cell types that endogenously express MLC1, demonstrating the relevance of the tissue culture models. Using a combination of biochemical, pharmacological and imaging methods, we also demonstrated that increased endoplasmatic reticulum-associated degradation and endo-lysosomal-associated degradation can contribute to the cell surface expression defect of the mutants. Based on these results, we suggest that MLC1 mutations reduce protein levels in vivo. Since the expression defect of the mutants could be rescued by exposing the mutant-protein expressing cells to low temperature and glycerol, a chemical chaperone, we propose that MLC belongs to the class of conformational diseases. Therefore, we suggest the use of pharmacological strategies that improve MLC1 expression to treat MLC patients. PMID:18757878

  13. Comparing dose in the build-up region between compensator- and MLC-based IMRT.

    PubMed

    Javedan, Khosrow; Zhang, Geoffrey G; Hoffe, Sarah; Feygelman, Vladimir; Forster, Kenneth

    2012-01-01

    The build-up dose in the megavoltage photon beams can be a limiting factor in intensity-modulated radiation therapy (IMRT) treatments. Excessive surface dose can cause patient discomfort and treatment interruptions, while underdosing may lead to tumor repopulation and local failure. Dose in the build-up region was investigated for IMRT delivery with solid brass compensator technique(compensator-based IMRT) and compared with that of multileaf collimator (MLC)-based IMRT. A Varian Trilogy linear accelerator equipped with an MLC was used for beam delivery. A special solid brass step-wise compensator was designed and built for testing purposes. Two step-and-shoot MLC fields were programmed to produce a similar modulated step-wise dose profile. The MLC and compensator dose profiles were measured and adjusted to match at the isocenter depth of 10 cm. Build-up dose in the 1-5 mm depth range was measured with an ultrathin window, fixed volume parallel plate ionization chamber. Monte Carlo simulations were used to model the brass compensator and step-and-shoot MLC fields. The measured and simulated profiles for the two IMRT techniques were matched at the isocenter depth of 10 cm. Different component contributions to the shallow dose, including the MLC scatter, were quantified. Mean spectral energies for the open and filtered beams were calculated. The compensator and MLC profiles at 10 cm depth were matched better than ± 1.5%. The build-up dose was up to 7% lower for compensator IMRT compared to MLC IMRT due to beam hardening in the brass. Low-energy electrons contribute 22% and 15% dose at 1 mm depth for compensator and MLC modalities, respectively. Compensator-based IMRT delivers less dose in the build-up region than MLC-based IMRT does, even though a compensator is closer to the skin than the MLC. PMID:22955641

  14. Keeping Kids Still during Exams

    MedlinePlus

    ... Keeping Kids Still During Exams Photo courtesy of Modern Way Immobilizers Inc., Clifton, Tenn. Nothing is more ... no se muevan durante exámenes Foto cortesía de Modern Way Immobilizers, Inc, Clifton, Tenn. Nada produce más ...

  15. Exam Schools from the Inside

    ERIC Educational Resources Information Center

    Finn, Chester E., Jr.; Hockett, Jessica

    2012-01-01

    Sometimes called "exam schools," academically selective institutions have long been a part of the American secondary-education landscape. The schools are diverse in origin and purpose. No single catalyst describes why or how they began as or morphed into academically selective institutions. A number of them were products of the country's efforts…

  16. Combining MLC and SVM Classifiers for Learning Based Decision Making: Analysis and Evaluations

    PubMed Central

    Zhang, Yi; Ren, Jinchang; Jiang, Jianmin

    2015-01-01

    Maximum likelihood classifier (MLC) and support vector machines (SVM) are two commonly used approaches in machine learning. MLC is based on Bayesian theory in estimating parameters of a probabilistic model, whilst SVM is an optimization based nonparametric method in this context. Recently, it is found that SVM in some cases is equivalent to MLC in probabilistically modeling the learning process. In this paper, MLC and SVM are combined in learning and classification, which helps to yield probabilistic output for SVM and facilitate soft decision making. In total four groups of data are used for evaluations, covering sonar, vehicle, breast cancer, and DNA sequences. The data samples are characterized in terms of Gaussian/non-Gaussian distributed and balanced/unbalanced samples which are then further used for performance assessment in comparing the SVM and the combined SVM-MLC classifier. Interesting results are reported to indicate how the combined classifier may work under various conditions. PMID:26089862

  17. Combining MLC and SVM Classifiers for Learning Based Decision Making: Analysis and Evaluations.

    PubMed

    Zhang, Yi; Ren, Jinchang; Jiang, Jianmin

    2015-01-01

    Maximum likelihood classifier (MLC) and support vector machines (SVM) are two commonly used approaches in machine learning. MLC is based on Bayesian theory in estimating parameters of a probabilistic model, whilst SVM is an optimization based nonparametric method in this context. Recently, it is found that SVM in some cases is equivalent to MLC in probabilistically modeling the learning process. In this paper, MLC and SVM are combined in learning and classification, which helps to yield probabilistic output for SVM and facilitate soft decision making. In total four groups of data are used for evaluations, covering sonar, vehicle, breast cancer, and DNA sequences. The data samples are characterized in terms of Gaussian/non-Gaussian distributed and balanced/unbalanced samples which are then further used for performance assessment in comparing the SVM and the combined SVM-MLC classifier. Interesting results are reported to indicate how the combined classifier may work under various conditions. PMID:26089862

  18. Exit Exam as Academic Performance Indicator

    ERIC Educational Resources Information Center

    Al Ahmad, Mahmoud; Al Marzouqi, Ali H.; Hussien, Mousa

    2014-01-01

    This paper focuses on the impact of exit exams on different elements of the educational process, namely: curriculum development, students and instructors. A 50-question multiple-choice Exit Exam was prepared by Electrical Engineering (EE) faculty members covering a poll of questions from EE core courses. A copy of the Exit Exam applied during each…

  19. Cumulative Exams in the Introductory Psychology Course

    ERIC Educational Resources Information Center

    Lawrence, Natalie K.

    2013-01-01

    Many teachers require their students to take cumulative exams, but there are surprisingly few studies that examine the benefits of such exams. The purpose of this study was to determine whether introductory psychology students who take cumulative exams throughout the semester would have better long-term retention than students who take a…

  20. Small field dosimetric characterization of a new 160-leaf MLC

    NASA Astrophysics Data System (ADS)

    Cranmer-Sargison, G.; Liu, P. Z. Y.; Weston, S.; Suchowerska, N.; Thwaites, D. I.

    2013-10-01

    The goal of this work was to perform a 6 MV small field characterization of the new Agility 160-leaf multi-leaf collimator (MLC) from Elekta. This included profile measurement analysis and central axis relative output measurements using various diode detectors and an air-core fiber optic scintillation dosimeter (FOD). Data was acquired at a depth of 10.0 cm for field sizes of 1.0, 0.9, 0.8, 0.7, 0.6 and 0.5 cm. Three experimental data sets, comprised of five readings, were made for both the relative output and profile measurements. Average detector-specific output ratios (\\overline {OR} _{det}^{f_{clin} }) were calculated with respect to a field size of 3.0 cm and small field replacement correction factors (\\mathop k\

  1. Translating bed total body irradiation lung shielding and dose optimization using asymmetric MLC apertures.

    PubMed

    Ahmed, Shahbaz; Brown, Derek; Ahmed, Saad B S; Kakakhel, Muhammad B; Muhammad, Wazir; Hussain, Amjad

    2016-01-01

    A revised translating bed total body irradiation (TBI) technique is developed for shielding organs at risk (lungs) to tolerance dose limits, and optimizing dose distribution in three dimensions (3D) using an asymmetrically-adjusted, dynamic multileaf collimator. We present a dosimetric comparison of this technique with a previously developed symmetric MLC-based TBI technique. An anthropomor-phic RANDO phantom is CT scanned with 3 mm slice thickness. Radiological depths (RD) are calculated on individual CT slices along the divergent ray lines. Asymmetric MLC apertures are defined every 9 mm over the phantom length in the craniocaudal direction. Individual asymmetric MLC leaf positions are optimized based on RD values of all slices for uniform dose distributions. Dose calculations are performed in the Eclipse treatment planning system over these optimized MLC apertures. Dose uniformity along midline of the RANDO phantom is within the confidence limit (CL) of 2.1% (with a confidence probability p = 0.065). The issue of over- and underdose at the interfaces that is observed when symmetric MLC apertures are used is reduced from more than ± 4% to less than ± 1.5% with asymmetric MLC apertures. Lungs are shielded by 20%, 30%, and 40% of the prescribed dose by adjusting the MLC apertures. Dose-volume histogram analysis confirms that the revised technique provides effective lung shielding, as well as a homogeneous dose coverage to the whole body. The asymmetric technique also reduces hot and cold spots at lung-tissue interfaces compared to previous symmetric MLC-based TBI technique. MLC-based shielding of OARs eliminates the need to fabricate and setup cumbersome patient-specific physical blocks. PMID:27074477

  2. Reducing errant ordered radiology exams.

    PubMed

    Duman, Benjamin; Martin, Patrick

    2012-01-01

    With grant funds, Providence Saint Patrick Hospital set out to reduce the occurrences of errant ordered radiology exams from clinicians. The goal was to also provide a tool that would assist in reducing unwarranted dose from diagnostic imaging modalities. An interactive web based utility for CT protocols was developed, which included ACR Appropriateness Criteria that was easy to use and maintain. The second stage of the program will be expanded to include more modalities, as well as to provide patients with a convenient source of information. PMID:22413608

  3. Monte Carlo implementation, validation, and characterization of a 120 leaf MLC

    SciTech Connect

    Fix, Michael K.; Volken, Werner; Frei, Daniel; Frauchiger, Daniel; Born, Ernst J.; Manser, Peter

    2011-10-15

    Purpose: Recently, the new high definition multileaf collimator (HD120 MLC) was commercialized by Varian Medical Systems providing high resolution in the center section of the treatment field. The aim of this work is to investigate the characteristics of the HD120 MLC using Monte Carlo (MC) methods. Methods: Based on the information of the manufacturer, the HD120 MLC was implemented into the already existing Swiss MC Plan (SMCP). The implementation has been configured by adjusting the physical density and the air gap between adjacent leaves in order to match transmission profile measurements for 6 and 15 MV beams of a Novalis TX. These measurements have been performed in water using gafchromic films and an ionization chamber at an SSD of 95 cm and a depth of 5 cm. The implementation was validated by comparing diamond measured and calculated penumbra values (80%-20%) for different field sizes and water depths. Additionally, measured and calculated dose distributions for a head and neck IMRT case using the DELTA{sup 4} phantom have been compared. The validated HD120 MLC implementation has been used for its physical characterization. For this purpose, phase space (PS) files have been generated below the fully closed multileaf collimator (MLC) of a 40 x 22 cm{sup 2} field size for 6 and 15 MV. The PS files have been analyzed in terms of energy spectra, mean energy, fluence, and energy fluence in the direction perpendicular to the MLC leaves and have been compared with the corresponding data using the well established Varian 80 leaf (MLC80) and Millennium M120 (M120 MLC) MLCs. Additionally, the impact of the tongue and groove design of the MLCs on dose has been characterized. Results: Calculated transmission values for the HD120 MLC are 1.25% and 1.34% in the central part of the field for the 6 and 15 MV beam, respectively. The corresponding ionization chamber measurements result in a transmission of 1.20% and 1.35%. Good agreement has been found for the comparison between transmission profiles resulting from MC simulations and film measurements. The simulated and measured values for the penumbra agreed within <0.5 mm for all field sizes, depths, and beam energies, and a good agreement has been found between the measured and the calculated dose distributions for the IMRT case. The total energy spectra are almost identical for the three MLCs. However, the mean energy, fluence and energy fluence are significantly different. Due to the different leaf widths of the MLCs, the shape of these distributions is different, each representing its leave structure. Due to the increase in width from the inner to the outer HD120 MLC leaves, the fluence and energy fluence clearly decrease below the outer leaves. The MLC80 and the M120 MLC resulted in an increase of the fluence and energy fluence compared with those resulted for the HD120 MLC. The dose reduction can exceed 20% compared with the dose of the open field due to the tongue and groove design of the HD120 MLC. Conclusions: The HD120 MLC has been successfully implemented into the SMCP. Comparisons between MC calculations and measurements show very good agreement. The SMCP is now able to calculate accurate dose distributions for treatment plans using the HD120 MLC.

  4. The first clinical implementation of electromagnetic transponder-guided MLC tracking

    PubMed Central

    Keall, Paul J.; Colvill, Emma; O’Brien, Ricky; Ng, Jin Aun; Poulsen, Per Rugaard; Eade, Thomas; Kneebone, Andrew; Booth, Jeremy T.

    2014-01-01

    Purpose: We report on the clinical process, quality assurance, and geometric and dosimetric results of the first clinical implementation of electromagnetic transponder-guided MLC tracking which occurred on 28 November 2013 at the Northern Sydney Cancer Centre. Methods: An electromagnetic transponder-based positioning system (Calypso) was modified to send the target position output to in-house-developed MLC tracking code, which adjusts the leaf positions to optimally align the treatment beam with the real-time target position. Clinical process and quality assurance procedures were developed and performed. The first clinical implementation of electromagnetic transponder-guided MLC tracking was for a prostate cancer patient being treated with dual-arc VMAT (RapidArc). For the first fraction of the first patient treatment of electromagnetic transponder-guided MLC tracking we recorded the in-room time and transponder positions, and performed dose reconstruction to estimate the delivered dose and also the dose received had MLC tracking not been used. Results: The total in-room time was 21 min with 2 min of beam delivery. No additional time was needed for MLC tracking and there were no beam holds. The average prostate position from the initial setup was 1.2 mm, mostly an anterior shift. Dose reconstruction analysis of the delivered dose with MLC tracking showed similar isodose and target dose volume histograms to the planned treatment and a 4.6% increase in the fractional rectal V60. Dose reconstruction without motion compensation showed a 30% increase in the fractional rectal V60 from that planned, even for the small motion. Conclusions: The real-time beam-target correction method, electromagnetic transponder-guided MLC tracking, has been translated to the clinic. This achievement represents a milestone in improving geometric and dosimetric accuracy, and by inference treatment outcomes, in cancer radiotherapy. PMID:24506591

  5. The first clinical implementation of electromagnetic transponder-guided MLC tracking

    SciTech Connect

    Keall, Paul J. O’Brien, Ricky; Ng, Jin Aun; Colvill, Emma; Poulsen, Per Rugaard; Eade, Thomas; Kneebone, Andrew; Booth, Jeremy T.

    2014-02-15

    Purpose: We report on the clinical process, quality assurance, and geometric and dosimetric results of the first clinical implementation of electromagnetic transponder-guided MLC tracking which occurred on 28 November 2013 at the Northern Sydney Cancer Centre. Methods: An electromagnetic transponder-based positioning system (Calypso) was modified to send the target position output to in-house-developed MLC tracking code, which adjusts the leaf positions to optimally align the treatment beam with the real-time target position. Clinical process and quality assurance procedures were developed and performed. The first clinical implementation of electromagnetic transponder-guided MLC tracking was for a prostate cancer patient being treated with dual-arc VMAT (RapidArc). For the first fraction of the first patient treatment of electromagnetic transponder-guided MLC tracking we recorded the in-room time and transponder positions, and performed dose reconstruction to estimate the delivered dose and also the dose received had MLC tracking not been used. Results: The total in-room time was 21 min with 2 min of beam delivery. No additional time was needed for MLC tracking and there were no beam holds. The average prostate position from the initial setup was 1.2 mm, mostly an anterior shift. Dose reconstruction analysis of the delivered dose with MLC tracking showed similar isodose and target dose volume histograms to the planned treatment and a 4.6% increase in the fractional rectal V{sub 60}. Dose reconstruction without motion compensation showed a 30% increase in the fractional rectal V{sub 60} from that planned, even for the small motion. Conclusions: The real-time beam-target correction method, electromagnetic transponder-guided MLC tracking, has been translated to the clinic. This achievement represents a milestone in improving geometric and dosimetric accuracy, and by inference treatment outcomes, in cancer radiotherapy.

  6. Dynamic MLC leaf sequencing for integrated linear accelerator control systems

    SciTech Connect

    Popple, Richard A.; Brezovich, Ivan A.

    2011-11-15

    Purpose: Leaf positions for dynamic multileaf collimator (DMLC) intensity modulated radiation therapy must be closely synchronized with MU delivery. For the Varian C3 series MLC controller, if the planned trajectory (leaf position vs. MU) requires velocities exceeding the capability of the MLC, the leaves fall behind the planned positions, causing the controller to momentarily hold the beam and thereby introduce dosimetric errors. We investigated the merits of a new commercial linear accelerator, TrueBeam, that integrates MLC control with prospective dose rate modulation. If treatment is delivered at dose rates so high that leaves would fall behind, the controller reduces the dose rate such that harmony between MU and leaf position is preserved. Methods: For three sets of DMLC leaf trajectories, point doses and two-dimensional dose distributions were measured in phantom using an ionization chamber and film, respectively. The first set, delivered using both a TrueBeam and a conventional C3 controller, comprised a single leaf bank closing at planned velocities of 2.4, 7.1, and 14 cm/s. The maximum achievable leaf velocity for both systems was 3 cm/s. The remaining two sets were derived from clinical fluence maps using a commercial treatment planning system for a range of planned dose rates and were delivered using TrueBeam set to the maximum dose rate, 600 MU/min. Generating trajectories using a planned dose rate that is lower than the delivery dose rate effectively increased the leaf velocity constraint used by the planning system for trajectory calculation. The second set of leaf trajectories was derived from two fluence maps containing regions of zero fluence obtained from representative beams of two different patient treatment plans. The third set was obtained from all nine fields of a head and neck treatment plan. For the head and neck plan, dose-volume histograms of the spinal cord and target for each planned dose rate were obtained. Results: For the single closing leaf bank trajectories, the TrueBeam control system reduced the dose rate such that the leaf velocity was less than the maximum. Dose deviations relative to the 2.4 cm/s trajectory were less than 3%. For the conventional controller, the leaves repeatedly fell behind the planned positions until the beam hold threshold was reached, resulting in deviations of up to 19% relative to the 2.4 cm/s trajectory. For the two clinical fluence maps, reducing the planned dose rate reduced the dose in the zero fluence regions by 15% and 24% and increased the delivery time by 5 s and 14 s. No significant differences were noted in the high and intermediate dose regions measured using film. The DVHs for the head and neck plan showed a 10% reduction in cord dose for 20 MU/min relative to 600 MU/min sequencing dose rate, which was confirmed by measurement. No difference in target DVHs were observed. The reduction in cord dose increased total treatment time by 1.8 min. Conclusions: Leaf sequencing algorithms for integrated control systems should be modified to reflect the reduced importance of maximum leaf velocity for accurate dose delivery.

  7. High-level recombinant protein production by overexpression of Mlc in Escherichia coli.

    PubMed

    Cho, Sanghee; Shin, Dongwoo; Ji, Geun Eog; Heu, Sunggi; Ryu, Sangryeol

    2005-09-23

    Escherichia coli excretes acetate during aerobic growth on LB broth containing glucose and growth ceases before depletion of glucose because of the low pH caused by the accumulation of acetate. It has been known that the acetate accumulation is reduced even when E. coli is grown in the presence of high concentration of glucose if Mlc is overexpressed. The intracellular concentration of Mlc is very low in E. coli because of autoregulation and a low efficiency of mlc translation. We constructed various mutants that can express higher levels of Mlc using site-directed mutagenesis and one of the Mlc-overproducing mutant showed reduced glucose consumption rate and low production of acetate. The mutant showed higher foreign gene expression level than that of its parental strain in the presence of glucose. These results suggest that the Mlc overproducing E. coli strain having an improved ability of glucose utilization can be a better host for high-level production of useful recombinant proteins. PMID:15916829

  8. Real-time dynamic MLC tracking for inversely optimized arc radiotherapy

    PubMed Central

    Falk, Marianne; Rosenschöld, Per Munck Af; Keall, Paul; Cattell, Herbert; Cho, Byung Chul; Poulsen, Per; Povzner, Sergey; Sawant, Amit; Zimmerman, Jens; Korreman, Stine

    2010-01-01

    Background and Purpose Motion compensation with MLC tracking was tested for inversely optimized arc radiotherapy with special attention to the impact of the size of the target displacements and the angle of the leaf trajectory. Material and methods An MLC tracking algorithm was used to adjust the MLC positions according to the target movements using information from an optical real-time positioning management system. Two plans with collimator angles of 45° and 90°, respectively, were delivered and measured using the Delta4® dosimetric device moving in the superior-inferior direction with peak-to-peak displacements of 5, 10, 15, 20 and 25 mm and a cycle time of 6 s. Results Gamma index evaluation for plan delivery with MLC tracking gave a pass rate higher than 98% for criteria 3% and 3 mm for both plans and for all sizes of the target displacement. With no motion compensation, the average pass rate was 75% for plan 1 and 70% for plan 2 for 25 mm peak-to-peak displacement. Conclusion MLC tracking improves the accuracy of inversely optimized arc delivery for the cases studied. With MLC tracking, the dosimetric accuracy was independent of the magnitude of the peak-to-peak displacement of the target and not significantly affected by the angle between the leaf trajectory and the target movements. PMID:20089322

  9. Detecting MLC errors in stereotactic radiotherapy plans with a liquid filled ionization chamber array.

    PubMed

    O'Connor, Patrick; Seshadri, Venkatakrisnan; Charles, Paul

    2016-03-01

    Quality assurance of stereotactic radiotherapy demands the use of equipment with the highest resolution and sensitivity available. This study examines the sensitivity of a commercially available liquid-filled ionization chamber array-the Octavius 1000 SRS (PTW, Frieburg, Germany) for detecting small (sub-millimetre) multi-leaf collimator (MLC) alignment errors in static square fields (side length 16-40 mm). Furthermore, the effectiveness of detecting small MLC errors in clinical stereotactic radiotherapy patient plans using the device was also evaluated. The commonly used gamma pass rate metric (of the measurements compared with treatment planning system generated results) was used. The gamma pass rates were then evaluated as a function of MLC position error (MLC error size 0.1-2.5 mm). The detector array exhibited a drop in pass rate between plans without error and those which had MLC errors induced. For example a drop in pass rate of 4.5 % (gamma criteria 3 %, 1 mm) was observed when a 0.8 mm error was introduced into a 16 mm square field. Furthermore the drop in pass rate increased as the MLC position error increased. This study showed that the Octavius 1000 SRS array could be a useful tool for applications requiring the detection of small geometric delivery uncertainties. PMID:26979835

  10. Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis

    PubMed Central

    Brignone, Maria S.; Lanciotti, Angela; Visentin, Sergio; De Nuccio, Chiara; Molinari, Paola; Camerini, Serena; Diociaiuti, Marco; Petrini, Stefania; Minnone, Gaetana; Crescenzi, Marco; Laudiero, Luisa Bracci; Bertini, Enrico; Petrucci, Tamara C.; Ambrosini, Elena

    2014-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in the gene encoding MLC1, a membrane protein mainly expressed in astrocytes in the central nervous system. Although MLC1 function is unknown, evidence is emerging that it may regulate ion fluxes. Using biochemical and proteomic approaches to identify MLC1 interactors and elucidate MLC1 function we found that MLC1 interacts with the vacuolar ATPase (V-ATPase), the proton pump that regulates endosomal acidity. Because we previously showed that in intracellular organelles MLC1 directly binds Na, K-ATPase, which controls endosomal pH, we studied MLC1 endosomal localization and trafficking and MLC1 effects on endosomal acidity and function using human astrocytoma cells overexpressing wild-type (WT) MLC1 or MLC1 carrying pathological mutations. We found that WT MLC1 is abundantly expressed in early (EEA1+, Rab5+) and recycling (Rab11+) endosomes and uses the latter compartment to traffic to the plasma membrane during hyposmotic stress. We also showed that WT MLC1 limits early endosomal acidification and influences protein trafficking in astrocytoma cells by stimulating protein recycling, as revealed by FITC-dextran measurement of endosomal pH and transferrin protein recycling assay, respectively. WT MLC1 also favors recycling to the plasma-membrane of the TRPV4 cation channel which cooperates with MLC1 to activate calcium influx in astrocytes during hyposmotic stress. Although MLC disease-causing mutations differentially affect MLC1 localization and trafficking, all the mutated proteins fail to influence endosomal pH and protein recycling. This study demonstrates that MLC1 modulates endosomal pH and protein trafficking suggesting that alteration of these processes contributes to MLC pathogenesis. PMID:24561067

  11. Detailed analysis of latencies in image-based dynamic MLC tracking

    SciTech Connect

    Poulsen, Per Rugaard; Cho, Byungchul; Sawant, Amit; Ruan, Dan; Keall, Paul J.

    2010-09-15

    Purpose: Previous measurements of the accuracy of image-based real-time dynamic multileaf collimator (DMLC) tracking show that the major contributor to errors is latency, i.e., the delay between target motion and MLC response. Therefore the purpose of this work was to develop a method for detailed analysis of latency contributions during image-based DMLC tracking. Methods: A prototype DMLC tracking system integrated with a linear accelerator was used for tracking a phantom with an embedded fiducial marker during treatment delivery. The phantom performed a sinusoidal motion. Real-time target localization was based on x-ray images acquired either with a portal imager or a kV imager mounted orthogonal to the treatment beam. Each image was stored in a file on the imaging workstation. A marker segmentation program opened the image file, determined the marker position in the image, and transferred it to the DMLC tracking program. This program estimated the three-dimensional target position by a single-imager method and adjusted the MLC aperture to the target position. Imaging intervals {Delta}T{sub image} from 150 to 1000 ms were investigated for both kV and MV imaging. After the experiments, the recorded images were synchronized with MLC log files generated by the MLC controller and tracking log files generated by the tracking program. This synchronization allowed temporal analysis of the information flow for each individual image from acquisition to completed MLC adjustment. The synchronization also allowed investigation of the MLC adjustment dynamics on a considerably finer time scale than the 50 ms time resolution of the MLC log files. Results: For {Delta}T{sub image}=150 ms, the total time from image acquisition to completed MLC adjustment was 380{+-}9 ms for MV and 420{+-}12 ms for kV images. The main part of this time was from image acquisition to completed image file writing (272 ms for MV and 309 ms for kV). Image file opening (38 ms), marker segmentation (4 ms), MLC position calculation (16 ms), and MLC adjustment (52 ms) were considerably faster. For {Delta}T{sub image}=1000 ms, the total time from image acquisition to completed MLC adjustment increased to 1030{+-}62 ms (MV) and 1330{+-}52 ms (kV) mainly because of delayed image file writing. The MLC adjustment duration was constant 52 ms ({+-}3 ms) for MLC adjustments below 1.1 mm and increased linearly for larger MLC adjustments. Conclusions: A method for detailed time analysis of each individual real-time position signal for DMLC tracking has been developed and applied to image-based tracking. The method allows identification of the major contributors to latency and therefore a focus for reducing this latency. The method could be an important tool for the reconstruction of the delivered target dose during DMLC tracking as it provides synchronization between target motion and MLC motion.

  12. Tailoring the Preparticipation Exam to Female Athletes.

    ERIC Educational Resources Information Center

    Johnson, Mimi D.

    1992-01-01

    Discusses the basics of the preparticipation exam, focusing on aspects specific to females, such as menstrual dysfunction, disordered eating, and orthopedic problems such as scoliosis and patellofemoral pain. Health history questionnaire and other parts of the exam are included in six tables. (SM)

  13. From Exam Factories to Communities of Discovery

    ERIC Educational Resources Information Center

    Coffield, Frank; Williamson, Bill

    2011-01-01

    The British current model of education has turned schools into exam factories and further education colleges and universities into skills factories for British industry. In their book, "From Exam Factories to Communities of Discovery: the Democratic Route," the authors offer an alternative way of thinking and talking about education, as well as…

  14. Physics Exams that Promote Collaborative Learning

    NASA Astrophysics Data System (ADS)

    Wieman, Carl E.; Rieger, Georg W.; Heiner, Cynthia E.

    2014-01-01

    The two-stage exam is a relatively simple way to introduce collaborative learning and formative assessment into an exam. Their use is rapidly growing in the physics department at the University of British Columbia, as both students and faculty find them rewarding. In a two-stage exam students first complete and turn in the exam individually, and then, working in small groups, answer the exam questions again. During the second stage, the room is filled with spirited and effective debate with nearly every student participating. This provides students with immediate targeted feedback supplied by discussions with their peers. Furthermore, we see indications that the use of this exam format not only ensures consistency across interactive course components, but it also positively impacts how students approach the other collaborative course components. This is accomplished without losing the summative assessment of individual performance that is the expectation of exams for most instructors. In this paper we describe how to implement two-stage exams and provide arguments why they should be part of physics courses that use interactive engagement and social/collaborative learning methods.

  15. Making Exam Preparation An Enjoyable Experience

    ERIC Educational Resources Information Center

    Lukosch, Stephan; Schummer, Till

    2006-01-01

    During oral exams at the German distance learning university, we noticed that students fear that they will be faced with questions that they have not anticipated. In our opinion, this is mainly because students have no chance to train and thereby gather positive experiences with exam situations as they are distributed all over Germany and thus it…

  16. From Exam Factories to Communities of Discovery

    ERIC Educational Resources Information Center

    Coffield, Frank; Williamson, Bill

    2011-01-01

    The British current model of education has turned schools into exam factories and further education colleges and universities into skills factories for British industry. In their book, "From Exam Factories to Communities of Discovery: the Democratic Route," the authors offer an alternative way of thinking and talking about education, as well as

  17. How External Exit Exams Spur Achievement.

    ERIC Educational Resources Information Center

    Bishop, John H.; Mane, Ferran; Bishop, Michael

    2001-01-01

    Compared with minimum competency tests, curriculum-based external exit exams provide better measures of students' achievement levels. Analysis of Third Mathematics and Science Study data shows that 13 year-olds from exit-exam countries are ahead of nonparticipating countries. Effects on college enrollment, job success, and test scores are…

  18. Profile of State High School Exit Exam Policies. New York

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on New York's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  19. Profile of State High School Exit Exam Policies. Tennessee

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Tennessee's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  20. Profile of State High School Exit Exam Policies. New Jersey

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on New Jersey's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  1. Profile of State High School Exit Exam Policies. New Mexico

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on New Mexico's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  2. Profile of State High School Exit Exam Policies. Oregon

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Oregon's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  3. Profile of State High School Exit Exam Policies. Oklahoma

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Oklahoma's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  4. Profile of State High School Exit Exam Policies. Nevada

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Nevada's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  5. Profile of State High School Exit Exam Policies. Ohio

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Ohio's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  6. Profile of State High School Exit Exam Policies. Virginia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Virginia's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  7. Profile of State High School Exit Exam Policies. Louisiana

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Louisiana's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  8. Profile of State High School Exit Exam Policies. Minnesota

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Minnesota's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  9. Profile of State High School Exit Exam Policies. Washington

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Washington's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  10. Profile of State High School Exit Exam Policies. Arkansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Arkansas' high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  11. Profile of State High School Exit Exam Policies. Florida

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Florida's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  12. Profile of State High School Exit Exam Policies. Texas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Texas' high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  13. Profile of State High School Exit Exam Policies. Missouri

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Missouri's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  14. Profile of State High School Exit Exam Policies. Idaho

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Idaho's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  15. Profile of State High School Exit Exam Policies. Indiana

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Indiana's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  16. Profile of State High School Exit Exam Policies. Mississippi

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Mississippi's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  17. Profile of State High School Exit Exam Policies. Alaska

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Alaska's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  18. Profile of State High School Exit Exam Policies. Maryland

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Maryland's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  19. Profile of State High School Exit Exam Policies. Georgia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Georgia's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  20. Profile of State High School Exit Exam Policies. California

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on California's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  1. Profile of State High School Exit Exam Policies. Arizona

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Arizona's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  2. Profile of State High School Exit Exam Policies. Alabama

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Alabama's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  3. Profile of State High School Exit Exam Policies. Delaware

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Delaware's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  4. Profile of State High School Exit Exam Policies. Connecticut

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Connecticut's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  5. SU-E-T-195: Gantry Angle Dependency of MLC Leaf Position Error

    SciTech Connect

    Ju, S; Hong, C; Kim, M; Chung, K; Kim, J; Han, Y; Ahn, S; Chung, S; Shin, E; Shin, J; Kim, H; Kim, D; Choi, D

    2014-06-01

    Purpose: The aim of this study was to investigate the gantry angle dependency of the multileaf collimator (MLC) leaf position error. Methods: An automatic MLC quality assurance system (AutoMLCQA) was developed to evaluate the gantry angle dependency of the MLC leaf position error using an electronic portal imaging device (EPID). To eliminate the EPID position error due to gantry rotation, we designed a reference maker (RM) that could be inserted into the wedge mount. After setting up the EPID, a reference image was taken of the RM using an open field. Next, an EPID-based picket-fence test (PFT) was performed without the RM. These procedures were repeated at every 45° intervals of the gantry angle. A total of eight reference images and PFT image sets were analyzed using in-house software. The average MLC leaf position error was calculated at five pickets (-10, -5, 0, 5, and 10 cm) in accordance with general PFT guidelines using in-house software. This test was carried out for four linear accelerators. Results: The average MLC leaf position errors were within the set criterion of <1 mm (actual errors ranged from -0.7 to 0.8 mm) for all gantry angles, but significant gantry angle dependency was observed in all machines. The error was smaller at a gantry angle of 0° but increased toward the positive direction with gantry angle increments in the clockwise direction. The error reached a maximum value at a gantry angle of 90° and then gradually decreased until 180°. In the counter-clockwise rotation of the gantry, the same pattern of error was observed but the error increased in the negative direction. Conclusion: The AutoMLCQA system was useful to evaluate the MLC leaf position error for various gantry angles without the EPID position error. The Gantry angle dependency should be considered during MLC leaf position error analysis.

  6. A New Comprehensive Final Exam

    NASA Astrophysics Data System (ADS)

    Bhavsar, Suketu P.

    2015-01-01

    Instructors aspire for students to master all the material covered. The final exam should assess the breadth and depth of their learning and be a significant basis for the final grade. I insist on a comprehensive final because I want students to review early material in light of later topics. I believe that this helps students create connections, integrate understanding, and retain knowledge for the long term. For non-science majors, reviewing and retaining the large amount of astronomy material is daunting. I experimented with a final exam format that calmed their fears and encouraged thorough review. It is only practical for a class of about twenty students or less. I provided a number of challenging conceptual and problem solving questions (at least as many as there were students), crafted to interconnect and span the entire range of topics. The order of the questions reflected the sequence in which the topics had been discussed. Students received these questions in ample time to prepare prior to the final. A student could bring up to 5 standard sheets of notes to the final. At the final, each student picked a number out of a hat. This was the question they had to answer in a 5-minute presentation. They were allowed 15 minutes for a final preparation during which they could use their 5 pages of notes. The presentations were given in order, 1- 20. Written comments on at least 10 other talks, explaining what was missed or correcting a mistake were required. They were graded both on their talk and on their comments. This format required students to be prepared for any question and encouraged interaction and communication while studying. Knowing the questions beforehand provided a guide to their studying as well as allayed their fears about what could be asked. The students also received guidance to what constituted a good answer, namely accuracy (correct scientific argument, appropriate facts, no irrelevant material), thoroughness (answered the complete questions, covered relevant material) and the quality of the presentation (polished, professional, use of demonstrations, graphs, pictures etc. and time appropriately to present a clear answer). I will describe this first attempt.

  7. Dose domain regularization of MLC leaf patterns for highly complex IMRT plans

    SciTech Connect

    Nguyen, Dan; Yu, Victoria Y.; Ruan, Dan; Cao, Minsong; Low, Daniel A.; Sheng, Ke; O’Connor, Daniel

    2015-04-15

    Purpose: The advent of automated beam orientation and fluence optimization enables more complex intensity modulated radiation therapy (IMRT) planning using an increasing number of fields to exploit the expanded solution space. This has created a challenge in converting complex fluences to robust multileaf collimator (MLC) segments for delivery. A novel method to regularize the fluence map and simplify MLC segments is introduced to maximize delivery efficiency, accuracy, and plan quality. Methods: In this work, we implemented a novel approach to regularize optimized fluences in the dose domain. The treatment planning problem was formulated in an optimization framework to minimize the segmentation-induced dose distribution degradation subject to a total variation regularization to encourage piecewise smoothness in fluence maps. The optimization problem was solved using a first-order primal-dual algorithm known as the Chambolle-Pock algorithm. Plans for 2 GBM, 2 head and neck, and 2 lung patients were created using 20 automatically selected and optimized noncoplanar beams. The fluence was first regularized using Chambolle-Pock and then stratified into equal steps, and the MLC segments were calculated using a previously described level reducing method. Isolated apertures with sizes smaller than preset thresholds of 1–3 bixels, which are square units of an IMRT fluence map from MLC discretization, were removed from the MLC segments. Performance of the dose domain regularized (DDR) fluences was compared to direct stratification and direct MLC segmentation (DMS) of the fluences using level reduction without dose domain fluence regularization. Results: For all six cases, the DDR method increased the average planning target volume dose homogeneity (D95/D5) from 0.814 to 0.878 while maintaining equivalent dose to organs at risk (OARs). Regularized fluences were more robust to MLC sequencing, particularly to the stratification and small aperture removal. The maximum and mean aperture sizes using the DDR were consistently larger than those from DMS for all tested number of segments. Conclusions: The fluence map to MLC segmentation conversion problem was formulated as a secondary optimization problem in the dose domain to minimize the smoothness-regularized dose discrepancy. The large scale optimization problem was solved using a primal-dual algorithm that transformed complicated fluences into maps that were more robust to the MLC segmentation and sequencing, affording fewer and larger segments with minimal degradation to dose distribution.

  8. MLC1 mutations in Japanese patients with megalencephalic leukoencephalopathy with subcortical cysts

    PubMed Central

    Shimada, Shino; Shimojima, Keiko; Masuda, Teruaki; Nakayama, Yoshiaki; Kohji, Toshihiko; Tsukamoto, Hiroko; Matsubasa, Tadashi; Oka, Akira; Yamamoto, Toshiyuki

    2014-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal recessive neurological disorder manifesting early onset macrocephaly and delayed-onset neurological deterioration. Characteristic radiological findings revealed by brain magnetic resonance imaging are the most important factors for obtaining a clinical diagnosis. In this study, we analyzed the causative gene, MLC1, in seven unrelated Japanese patients. The most common mutation in our study was p.S93L; this mutation was observed in 11 alleles (78.6%). The second most common mutation, p.A275D, was observed in two alleles (14.3%). A novel single-nucleotide deletion, c.578delG (p.V194Sfs*2), was identified in one allele. As the clinical severities of patients with MLC were variable even among those sharing identical genotypes, this condition may be modified by environmental factors, modifier genes or epigenetic factors.

  9. Monte Carlo simulation of a dynamic MLC based on a multiple source model.

    PubMed

    Fix, M K; Manser, P; Born, E J; Mini, R; Regsegger, P

    2001-12-01

    Detailed knowledge of the characteristics of the radiation field shaped by a multileaf collimator (MLC) is essential in intensity modulated radiotherapy (IMRT). A previously developed multiple source model (MSM) for a 6 MV beam was extended to a 15 MV beam and supplemented with an accurate model of an 80-leaf dynamic MLC. Using the supplemented MSM and the MC code GEANT, lateral dose distributions were calculated in a water phantom and a portal water phantom. A field which is normally used for the validation of the step and shoot technique and a field from a realistic IMRT treatment plan delivered with dynamic MLC are investigated. To assess possible spectral changes caused by the modulation of beam intensity by an MLC, the energy spectra in five portal planes were calculated for moving slits of different widths. The extension of the MSM to 15 MV was validated by analysing energy fluences, depth doses and dose profiles. In addition, the MC-calculated primary energy spectrum was verified with an energy spectrum which was reconstructed from transmission measurements. MC-calculated dose profiles using the MSM for the step and shoot case and for the dynamic MLC case are in very good agreement with the measured data from film dosimetry. The investigation of a 13 cm wide field shows an increase in mean photon energy of up to 16% for the 0.25 cm slit compared to the open beam for 6 MV and of up to 6% for 15 MV, respectively. In conclusion, the MSM supplemented with the dynamic MLC has proven to be a powerful tool for investigational and benchmarking purposes or even for dose calculations in IMRT. PMID:11768503

  10. Fast motion-including dose error reconstruction for VMAT with and without MLC tracking.

    PubMed

    Ravkilde, Thomas; Keall, Paul J; Grau, Cai; Høyer, Morten; Poulsen, Per R

    2014-12-01

    Multileaf collimator (MLC) tracking is a promising and clinically emerging treatment modality for radiotherapy of mobile tumours. Still, new quality assurance (QA) methods are warranted to safely introduce MLC tracking in the clinic. The purpose of this study was to create and experimentally validate a simple model for fast motion-including dose error reconstruction applicable to intrafractional QA of MLC tracking treatments of moving targets.MLC tracking experiments were performed on a standard linear accelerator with prototype MLC tracking software guided by an electromagnetic transponder system. A three-axis motion stage reproduced eight representative tumour trajectories; four lung and four prostate. Low and high modulation 6 MV single-arc volumetric modulated arc therapy treatment plans were delivered for each trajectory with and without MLC tracking, as well as without motion for reference. Temporally resolved doses were measured during all treatments using a biplanar dosimeter. Offline, the dose delivered to each of 1069 diodes in the dosimeter was reconstructed with 500 ms temporal resolution by a motion-including pencil beam convolution algorithm developed in-house. The accuracy of the algorithm for reconstruction of dose and motion-induced dose errors throughout the tracking and non-tracking beam deliveries was quantified. Doses were reconstructed with a mean dose difference relative to the measurements of-0.5% (5.5% standard deviation) for cumulative dose. More importantly, the root-mean-square deviation between reconstructed and measured motion-induced 3%/3 mm γ failure rates (dose error) was 2.6%. The mean computation time for each calculation of dose and dose error was 295 ms. The motion-including dose reconstruction allows accurate temporal and spatial pinpointing of errors in absorbed dose and is adequately fast to be feasible for online use. An online implementation could allow treatment intervention in case of erroneous dose delivery in both tracking and non-tracking treatments. PMID:25383729

  11. Wogonin inhibits LPS-induced vascular permeability via suppressing MLCK/MLC pathway.

    PubMed

    Huang, Yujie; Luo, Xuwei; Li, Xiaorui; Song, Xiuming; Wei, Libin; Li, Zhiyu; You, Qidong; Guo, Qinglong; Lu, Na

    2015-09-01

    Wogonin, a naturally occurring monoflavonoid extracted from the root of Scutellaria baicalensis Georgi, has been shown to have anti-inflammatory and anti-tumor activities and inhibits oxidant stress-induced vascular permeability. However, the influence of wogonin on vascular hyperpermeability induced by overabounded inflammatory factors often appears in inflammatory diseases and tumor is not well known. In this study, we evaluate the effects of wogonin on LPS induced vascular permeability in human umbilical vein endothelial cells (HUVECs) and investigate the underlying mechanisms. We find that wogonin suppresses the LPS-stimulated hyperactivity and cytoskeleton remodeling of HUVECs, promotes the expression of junctional proteins including VE-Cadherin, Claudin-5 and ZO-1, as well as inhibits the invasion of MDA-MB-231 across EC monolayer. Miles vascular permeability assay proves that wogonin can restrain the extravasated Evans in vivo. The mechanism studies reveal that the expressions of TLR4, p-PLC, p-MLCK and p-MLC are decreased by wogonin without changing the total steady state protein levels of PLC, MLCK and MLC. Moreover, wogonin can also inhibit KCl-activated MLCK/MLC pathway, and further affect vascular permeability. Significantly, compared with wortmannin, the inhibitor of MLCK/MLC pathway, wogonin exhibits similar inhibition effects on the expression of p-MLCK, p-MLC and LPS-induced vascular hyperpermeability. Taken together, wogonin can inhibit LPS-induced vascular permeability by suppressing the MLCK/MLC pathway, suggesting a therapeutic potential for the diseases associated with the development of both inflammatory and tumor. PMID:25956732

  12. Anatomy-based, patient-specific VMAT QA using EPID or MLC log files.

    PubMed

    Defoor, Dewayne L; Vazquez-Quino, Luis A; Mavroidis, Panayiotis; Papanikolaou, Nikos; Stathakis, Sotirios

    2015-01-01

    In this project, we investigated the use of an electronic portal imaging device (EPID), together with the treatment planning system (TPS) and MLC log files, to determine the delivered doses to the patient and evaluate the agreement between the treatment plan and the delivered dose distribution. The QA analysis results are presented for 15 VMAT patients using the EPID measurements, the ScandiDos Delta4 dosimeter, and the beam fluence calculated from the multileaf collimator (MLC) log file. EPID fluence images were acquired in continuous acquisition mode for each of the patients and they were processed through an in-house MATLAB program to create an opening density matrix (ODM), which was used as the input fluence for the dose calculation in the TPS (Pinnacle3). The EPID used in this study was the aSi1000 Varian on a Novalis TX linac equipped with high-definition MLC. The actual MLC positions and gantry angles were retrieved from the MLC log files and the data were used to calculate the delivered dose distributions in Pinnacle. The resulting dose distributions were then compared against the corresponding planned dose distributions using the 3D gamma index with 3 mm/3% passing criteria. The ScandiDos Delta4 phantom was also used to measure a 2D dose distribution for all the 15 patients and a 2D gamma was calculated for each patient using the Delta4 software. The average 3D gamma using the EPID images was 96.1% ± 2.2%. The average 3D gamma using the log files was 98.7% ± 0.5%. The average 2D gamma from the Delta4 was 98.1% ± 2.1%. Our results indicate that the use of the EPID, combined with MLC log files and a TPS, is a viable method for QA of VMAT plans. PMID:26103490

  13. Disrupting MLC1 and GlialCAM and ClC-2 interactions in leukodystrophy entails glial chloride channel dysfunction

    NASA Astrophysics Data System (ADS)

    Hoegg-Beiler, Maja B.; Sirisi, Sònia; Orozco, Ian J.; Ferrer, Isidre; Hohensee, Svea; Auberson, Muriel; Gödde, Kathrin; Vilches, Clara; de Heredia, Miguel López; Nunes, Virginia; Estévez, Raúl; Jentsch, Thomas J.

    2014-03-01

    Defects in the astrocytic membrane protein MLC1, the adhesion molecule GlialCAM or the chloride channel ClC-2 underlie human leukoencephalopathies. Whereas GlialCAM binds ClC-2 and MLC1, and modifies ClC-2 currents in vitro, no functional connections between MLC1 and ClC-2 are known. Here we investigate this by generating loss-of-function Glialcam and Mlc1 mouse models manifesting myelin vacuolization. We find that ClC-2 is unnecessary for MLC1 and GlialCAM localization in brain, whereas GlialCAM is important for targeting MLC1 and ClC-2 to specialized glial domains in vivo and for modifying ClC-2’s biophysical properties specifically in oligodendrocytes (OLs), the cells chiefly affected by vacuolization. Unexpectedly, MLC1 is crucial for proper localization of GlialCAM and ClC-2, and for changing ClC-2 currents. Our data unmask an unforeseen functional relationship between MLC1 and ClC-2 in vivo, which is probably mediated by GlialCAM, and suggest that ClC-2 participates in the pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts.

  14. Evaluation of two methods of predicting MLC leaf positions using EPID measurements

    SciTech Connect

    Parent, Laure; Seco, Joao; Evans, Phil M.; Dance, David R.; Fielding, Andrew

    2006-09-15

    In intensity modulated radiation treatments (IMRT), the position of the field edges and the modulation within the beam are often achieved with a multileaf collimator (MLC). During the MLC calibration process, due to the finite accuracy of leaf position measurements, a systematic error may be introduced to leaf positions. Thereafter leaf positions of the MLC depend on the systematic error introduced on each leaf during MLC calibration and on the accuracy of the leaf position control system (random errors). This study presents and evaluates two methods to predict the systematic errors on the leaf positions introduced during the MLC calibration. The two presented methods are based on a series of electronic portal imaging device (EPID) measurements. A comparison with film measurements showed that the EPID could be used to measure leaf positions without introducing any bias. The first method, referred to as the 'central leaf method', is based on the method currently used at this center for MLC leaf calibration. It mimics the manner in which leaf calibration parameters are specified in the MLC control system and consequently is also used by other centers. The second method, a new method proposed by the authors and referred to as the ''individual leaf method,'' involves the measurement of two positions for each leaf (-5 and +15 cm) and the interpolation and extrapolation from these two points to any other given position. The central leaf method and the individual leaf method predicted leaf positions at prescribed positions of -11, 0, 5, and 10 cm within 2.3 and 1.0 mm, respectively, with a standard deviation (SD) of 0.3 and 0.2 mm, respectively. The individual leaf method provided a better prediction of the leaf positions than the central leaf method. Reproducibility tests for leaf positions of -5 and +15 cm were performed. The reproducibility was within 0.4 mm on the same day and 0.4 mm six weeks later (1 SD). Measurements at gantry angles of 0 deg., 90 deg., and 270 deg. for leaf positions of -5 and +15 cm showed no significant effect of gravity. The individual leaf method could be used in various applications to improve the accuracy of radiotherapy treatment from planning to delivery. Three cases are discussed: IMRT beam verification, MLC calibration and dose calcula0010ti.

  15. MLC901, a Traditional Chinese Medicine induces neuroprotective and neuroregenerative benefits after traumatic brain injury in rats.

    PubMed

    Quintard, H; Lorivel, T; Gandin, C; Lazdunski, M; Heurteaux, C

    2014-09-26

    Traumatic brain injury (TBI) is a frequent and clinically highly heterogeneous neurological disorder with large socioeconomic consequences. NeuroAid (MLC601 and MLC901), a Traditional Medicine used in China for patients after stroke has been previously reported to induce neuroprotection and neuroplasticity. This study was designed to evaluate the neuroprotective and neuroregenerative effects of MLC901 in a rat model of TBI. TBI was induced by a moderate lateral fluid percussion applied to the right parietal cortex. MLC901 was injected intraperitoneally at 2h post-TBI, and then administered in drinking water at a concentration of 10mg/ml until sacrifice of the animals. The cognitive deficits induced by TBI were followed by using the "what-where-when" task, which allows the measurement of episodic-like memory. MLC901 treatment decreased brain lesions induced by TBI. It prevented the serum increase of S-100 beta (S100B) and neuron-specific enolase (NSE), which may be markers to predict the neurologic outcome in human patients with TBI. MLC901 reduced the infarct volume when injected up to 2h post-TBI, prevented edema formation and assisted its resolution, probably via the regulation of aquaporin 4. These positive MLC901 effects were associated with an upregulation of vascular endothelial growth factor (VEGF) as well as an increase of endogenous hippocampal neurogenesis and gliogenesis around the lesion. Furthermore, MLC901 reduced cognitive deficits induced by TBI. Rats subjected to TBI displayed a suppression of temporal order memory, which was restored by MLC901. This work provides evidence that MLC901 has neuroprotective and neurorestorative actions, which lead to an improvement in the recovery of cognitive functions in a model of traumatic brain injury. PMID:24993477

  16. NOTE: Verification of a rounded leaf-end MLC model used in a radiotherapy treatment planning system

    NASA Astrophysics Data System (ADS)

    Williams, M. J.; Metcalfe, P.

    2006-02-01

    A new multileaf collimator (MLC) model has been incorporated into version 7.4 of the Pinnacle radiotherapy treatment planning system (Philips Radiation Oncology Systems, Milpitas, CA). The MLC model allows for rounded MLC leaf-ends and provides separate parameters for inter-leaf transmission, intra-leaf transmission and the tongue width of the MLC leaf. In this report we detail the method followed to commission the MLC model for a Varian 120-leaf Millennium MLC (Varian Medical Systems, Palo Alto, CA, USA) for both 6 and 10 MV photons, and test the validity of the model for an IMRT field. Dose profiles in water were measured for a range of square MLC field sizes and compared to the Pinnacle computed dose profiles; in addition, the dose distribution for a series of adjacent MLC fields was measured to observe the model's behaviour along match-lines. Based on these results intra-leaf transmissions of 1.5% for 6 MV and 1.8% for 10 MV, leaf-tip radius of 12.0 cm, an inter-leaf transmission of 0.5%, and a tongue width of 0.1 cm were chosen. Using these values to compute the planar dose distribution for a 6 MV IMRT field, the new version of Pinnacle displayed improved dosimetric agreement with the dose-to-water EPID image and ion chamber measurements when compared to the old version of Pinnacle, particularly along the MLC tongue edge and across match-lines. Discrepancies of up to 5% were observed between calculated and measured doses along match-lines for both 6 MV and 10 MV photons; however, the new MLC model did predict the presence of match-lines and was a significant improvement on the previous model.

  17. Oral Exams as a Tool for Teaching and Assessment

    ERIC Educational Resources Information Center

    Sayre, Eleanor C.

    2014-01-01

    Oral exams are a fruitful and practical alternative to written exams in small-enrolment Science classes. In an oral exam, the instructor can assess conceptual understanding, problem-solving, scientific communication skills, and a student's philosophy of science. In contrast, a written exam gives a much poorer picture of how students learn and

  18. Physics Exam Preparation: A Comparison of Three Methods

    ERIC Educational Resources Information Center

    Fakcharoenphol, Witat; Stelzer, Timothy

    2014-01-01

    In this clinical study on helping students prepare for an exam, we compared three different treatments. All students were asked to take a practice exam. One group was then given worked-out solutions for that exam, another group was given the solutions and targeted exercises to do as homework based on the result of their practice exam, and the…

  19. Oral Exams as a Tool for Teaching and Assessment

    ERIC Educational Resources Information Center

    Sayre, Eleanor C.

    2014-01-01

    Oral exams are a fruitful and practical alternative to written exams in small-enrolment Science classes. In an oral exam, the instructor can assess conceptual understanding, problem-solving, scientific communication skills, and a student's philosophy of science. In contrast, a written exam gives a much poorer picture of how students learn and…

  20. Profile of State High School Exit Exam Policies. Rhode Island

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Rhode Island's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam…

  1. Profile of State High School Exit Exam Policies. South Carolina

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on South Carolina's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam…

  2. Profile of State High School Exit Exam Policies. North Carolina

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on North Carolina's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam…

  3. Profile of State High School Exit Exam Policies. Massachusetts

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Massachusetts' high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam…

  4. INSTA-EXAM: A Card-Based Exam Preparation System that Eliminates Repeated Typing and Proofreading.

    ERIC Educational Resources Information Center

    Tauber, Robert T.

    1984-01-01

    A system that rivals today's computer-based exam preparation systems is described. The INSTA-EXAM system is 10 times faster than the more traditional, labor-intensive method of typing directly on stencil masters. Its ability to quickly and efficiently change, update, and delete information makes it especially useful. (RM)

  5. Use of dMLC for implementation of dynamic respiratory-gated radiation therapy

    SciTech Connect

    Pepin, Eric W.; Wu, Huanmei; Shirato, Hiroki

    2013-10-15

    Purpose: To simulate and evaluate the use of dynamic multileaf collimators (dMLC) in respiratory gating to compensate for baseline drift.Methods: Tumor motion tracking data from 30 lung tumors over 322 treatment fractions was analyzed with the finite state model. A dynamic respiratory gating window was established in real-time by determining the average positions during the previous two end-of-expiration breathing phases and centering the dMLC aperture on a weighted average of these positions. A simulated dMLC with physical motion constraints was used in dynamic gating treatment simulations. Fluence maps were created to provide a statistical description of radiation delivery for each fraction. Duty cycle was also calculated for each fraction.Results: The average duty cycle was 2.3% greater under dynamic gating conditions. Dynamic gating also showed higher fluences and less tumor obstruction. Additionally, dynamic gating required fewer beam toggles and each delivery period was longer on average than with static gating.Conclusions: The use of dynamic gating showed better performance than static gating and the physical constraints of a dMLC were shown to not be an impediment to dynamic gating.

  6. 6 MV dosimetric characterization of the 160 MLC, the new Siemens multileaf collimator

    SciTech Connect

    Tacke, Martin B.; Nill, Simeon; Haering, Peter; Oelfke, Uwe

    2008-05-15

    New technical developments constantly aim at improving the outcome of radiation therapy. With the use of a computer-controlled multileaf collimator (MLC), the quality of the treatment and the efficiency in patient throughput is significantly increased. New MLC designs aim to further enhance the advantages. In this article, we present the first detailed experimental investigation of the new 160 MLC{sup TM}, Siemens Medical Solutions. The assessment included the experimental investigation of typical MLC characteristics such as leakage, tongue-and-groove effect, penumbra, leaf speed, and leaf positioning accuracy with a 6 MV treatment beam. The leakage is remarkably low with an average of 0.37% due to a new design principle of slightly tilted leaves instead of the common tongue-and-groove design. But due to the tilt, the triangular tongue-and-groove effect occurs. Its magnitude of approximately 19% is similar to the dose defect measured for MLCs with the common tongue-and-groove design. The average longitudinal penumbra measured at depth d{sub max}=15 mm with standard 100x100 mm{sup 2} fields is 4.1{+-}0.5 mm for the central range and increases to 4.9{+-}1.3 mm for the entire field range of 400x400 mm{sup 2}. The increase is partly due to the single-focusing design and the large distance between the MLC and the isocenter enabling a large patient clearance. Regarding the leaf speed, different velocity tests were performed. The positions of the moving leaves were continuously recorded with the kilovoltage-imaging panel. The maximum leaf velocities measured were 42.9{+-}0.6 mm/s. In addition, several typical intensity-modulated radiation therapy treatments were performed and the delivery times compared to the Siemens OPTIFOCUS MLC. An average decrease of 11% in delivery time was observed. The experimental results presented in this article indicate that the dosimetric characteristics of the 160 MLC are capable of improving the quality of dose delivery with respect to precision and dose conformity.

  7. Impact of the MLC on the MRI field distortion of a prototype MRI-linac

    SciTech Connect

    Kolling, Stefan; Keall, Paul; Oborn, Brad

    2013-12-15

    Purpose: To cope with intrafraction tumor motion, integrated MRI-linac systems for real-time image guidance are currently under development. The multileaf collimator (MLC) is a key component in every state-of-the-art radiotherapy treatment system, allowing for accurate field shaping and tumor tracking. This work quantifies the magnetic impact of a widely used MLC on the MRI field homogeneity for such a modality.Methods: The finite element method was employed to model a MRI-linac assembly comprised of a 1.0 T split-bore MRI magnet and the key ferromagnetic components of a Varian Millennium 120 MLC, namely, the leaves and motors. Full 3D magnetic field maps of the system were generated. From these field maps, the peak-to-peak distortion within the MRI imaging volume was evaluated over a 30 cm diameter sphere volume (DSV) around the isocenter and compared to a maximum preshim inhomogeneity of 300 μT. Five parametric studies were performed: (1) The source-to-isocenter distance (SID) was varied from 100 to 200 cm, to span the range of a compact system to that with lower magnetic coupling. (2) The MLC model was changed from leaves only to leaves with motors, to determine the contribution to the total distortion caused by MLC leaves and motors separately. (3) The system was configured in the inline or perpendicular orientation, i.e., the linac treatment beam was oriented parallel or perpendicular to the magnetic field direction. (4) The treatment field size was varied from 0 × 0 to 20×20 cm{sup 2}, to span the range of clinical treatment fields. (5) The coil currents were scaled linearly to produce magnetic field strengths B{sub 0} of 0.5, 1.0, and 1.5 T, to estimate how the MLC impact changes with B{sub 0}.Results: (1) The MLC-induced MRI field distortion fell continuously with increasing SID. (2) MLC leaves and motors were found to contribute to the distortion in approximately equal measure. (3) Due to faster falloff of the fringe field, the field distortion was generally smaller in the perpendicular beam orientation. The peak-to-peak DSV distortion was below 300 μT at SID≥130 cm (perpendicular) and SID≥140 cm (inline) for the 1.0 T design. (4) The simulation of different treatment fields was identified to cause dynamic changes in the field distribution. However, the estimated residual distortion was below 1.2 mm geometric distortion at SID≥120 cm (perpendicular) and SID≥130 cm (inline) for a 10 mT/m frequency-encoding gradient. (5) Due to magnetic saturation of the MLC materials, the field distortion remained constant at B{sub 0}>1.0 T.Conclusions: This work shows that the MRI field distortions caused by the MLC cannot be ignored and must be thoroughly investigated for any MRI-linac system. The numeric distortion values obtained for our 1.0 T magnet may vary for other magnet designs with substantially different fringe fields, however the concept of modest increases in the SID to reduce the distortion to a shimmable level is generally applicable.

  8. Quantifying the gantry sag on linear accelerators and introducing an MLC-based compensation strategy

    PubMed Central

    Du, Weiliang; Gao, Song; Wang, Xiaochun; Kudchadker, Rajat J.

    2012-01-01

    Purpose: Gantry sag is one of the well-known sources of mechanical imperfections that compromise the spatial accuracy of radiation dose delivery. The objectives of this study were to quantify the gantry sag on multiple linear accelerators (linacs), to investigate a multileaf collimator (MLC)-based strategy to compensate for gantry sag, and to verify the gantry sag and its compensation with film measurements. Methods: The authors used the WinstonLutz method to measure gantry sag on three Varian linacs. A ball bearing phantom was imaged with megavolt radiation fields at 10 gantry angle intervals. The images recorded with an electronic portal imaging device were analyzed to derive the radiation isocenter and the gantry sag, that is, the superiorinferior wobble of the radiation field center, as a function of the gantry angle. The authors then attempted to compensate for the gantry sag by applying a gantry angle-specific correction to the MLC leaf positions. The gantry sag and its compensation were independently verified using film measurements. Results: Gantry sag was reproducible over a six-month measurement period. The maximum gantry sag was found to vary from 0.7 to 1.0 mm, depending on the linac and the collimator angle. The radiation field center moved inferiorly (i.e., away from the gantry) when the gantry was rotated from 0 to 180. After the MLC leaf position compensation was applied at 90 collimator angle, the maximum gantry sag was reduced to <0.2 mm. The film measurements at gantry angles of 0 and 180 verified the inferior shift of the radiation fields and the effectiveness of MLC compensation. Conclusions: The results indicate that gantry sag on a linac can be quantitatively measured using a simple phantom and an electronic portal imaging device. Reduction of gantry sag is feasible by applying a gantry angle-specific correction to MLC leaf positions at 90 collimator angle. PMID:22482636

  9. Quantifying the gantry sag on linear accelerators and introducing an MLC-based compensation strategy

    SciTech Connect

    Du Weiliang; Gao Song; Wang Xiaochun; Kudchadker, Rajat J.

    2012-04-15

    Purpose: Gantry sag is one of the well-known sources of mechanical imperfections that compromise the spatial accuracy of radiation dose delivery. The objectives of this study were to quantify the gantry sag on multiple linear accelerators (linacs), to investigate a multileaf collimator (MLC)-based strategy to compensate for gantry sag, and to verify the gantry sag and its compensation with film measurements. Methods: The authors used the Winston-Lutz method to measure gantry sag on three Varian linacs. A ball bearing phantom was imaged with megavolt radiation fields at 10 deg. gantry angle intervals. The images recorded with an electronic portal imaging device were analyzed to derive the radiation isocenter and the gantry sag, that is, the superior-inferior wobble of the radiation field center, as a function of the gantry angle. The authors then attempted to compensate for the gantry sag by applying a gantry angle-specific correction to the MLC leaf positions. The gantry sag and its compensation were independently verified using film measurements. Results: Gantry sag was reproducible over a six-month measurement period. The maximum gantry sag was found to vary from 0.7 to 1.0 mm, depending on the linac and the collimator angle. The radiation field center moved inferiorly (i.e., away from the gantry) when the gantry was rotated from 0 deg. to 180 deg. After the MLC leaf position compensation was applied at 90 deg. collimator angle, the maximum gantry sag was reduced to <0.2 mm. The film measurements at gantry angles of 0 deg. and 180 deg. verified the inferior shift of the radiation fields and the effectiveness of MLC compensation. Conclusions: The results indicate that gantry sag on a linac can be quantitatively measured using a simple phantom and an electronic portal imaging device. Reduction of gantry sag is feasible by applying a gantry angle-specific correction to MLC leaf positions at 90 deg. collimator angle.

  10. Mutations of MLC1 (KIAA0027), Encoding a Putative Membrane Protein, Cause Megalencephalic Leukoencephalopathy with Subcortical Cysts

    PubMed Central

    Leegwater, Peter A. J.; Yuan, Bao Qiang; van der Steen, Jeffrey; Mulders, Joyce; Könst, Andrea A. M.; Boor, P. K. Ilja; Mejaski-Bosnjak, Vlatka; van der Maarel, Silvère M.; Frants, Rune R.; Oudejans, Cees B. M.; Schutgens, Ruud B. H.; Pronk, Jan C.; van der Knaap, Marjo S.

    2001-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal recessive disorder characterized by macrocephaly, deterioration of motor functions with ataxia, and spasticity, eventuating in mental decline. The brain appears swollen on magnetic resonance imaging, with diffuse white-matter abnormalities and the invariable presence of subcortical cysts. MLC was recently localized on chromosome 22qtel. We have narrowed down the critical region by linkage analysis of 11 informative families with MLC to a region of ∼250 kb, containing four known genes. One family with two patients who were siblings did not display linkage between the MLC phenotype and any of the analyzed microsatellite markers on chromosome 22qtel, suggesting genetic heterogeneity and the existence of at least a second MLC locus. The maximum two-point LOD score for the 11 families was 6.6 at recombination fraction .02. Twelve different mutations in seven informative and six uninformative families were found in one of the candidate genes, KIAA0027, which we renamed “MLC1.” The gene encodes a putative membrane protein with eight predicted transmembrane domains. The patients of one family were compound heterozygotes for mutations that both introduced stop codons. The mutations further included frameshifts, splice-acceptor mutations, a putative splice-donor mutation, and amino acid substitutions of residues in predicted transmembrane domains. These data provide strong evidence that mutations of MLC1 cause the disease. PMID:11254442

  11. Mouse and computational models link Mlc2v dephosphorylation to altered myosin kinetics in early cardiac disease

    PubMed Central

    Sheikh, Farah; Ouyang, Kunfu; Campbell, Stuart G.; Lyon, Robert C.; Chuang, Joyce; Fitzsimons, Dan; Tangney, Jared; Hidalgo, Carlos G.; Chung, Charles S.; Cheng, Hongqiang; Dalton, Nancy D.; Gu, Yusu; Kasahara, Hideko; Ghassemian, Majid; Omens, Jeffrey H.; Peterson, Kirk L.; Granzier, Henk L.; Moss, Richard L.; McCulloch, Andrew D.; Chen, Ju

    2012-01-01

    Actin-myosin interactions provide the driving force underlying each heartbeat. The current view is that actin-bound regulatory proteins play a dominant role in the activation of calcium-dependent cardiac muscle contraction. In contrast, the relevance and nature of regulation by myosin regulatory proteins (for example, myosin light chain-2 [MLC2]) in cardiac muscle remain poorly understood. By integrating gene-targeted mouse and computational models, we have identified an indispensable role for ventricular Mlc2 (Mlc2v) phosphorylation in regulating cardiac muscle contraction. Cardiac myosin cycling kinetics, which directly control actin-myosin interactions, were directly affected, but surprisingly, Mlc2v phosphorylation also fed back to cooperatively influence calcium-dependent activation of the thin filament. Loss of these mechanisms produced early defects in the rate of cardiac muscle twitch relaxation and ventricular torsion. Strikingly, these defects preceded the left ventricular dysfunction of heart disease and failure in a mouse model with nonphosphorylatable Mlc2v. Thus, there is a direct and early role for Mlc2 phosphorylation in regulating actin-myosin interactions in striated muscle contraction, and dephosphorylation of Mlc2 or loss of these mechanisms can play a critical role in heart failure. PMID:22426213

  12. Therapeutic efficacy of Neuro AiD™ (MLC 601), a traditional Chinese medicine, in experimental traumatic brain injury.

    PubMed

    Tsai, Ming-Che; Chang, Ching-Ping; Peng, Syue-Wei; Jhuang, Kai-Sheng; Fang, Yi-Hsien; Lin, Mao-Tsun; Tsao, Thomas Chang-Yao

    2015-03-01

    Traumatic brain injury (TBI) causes increased release of several mediators from injured and dead cells and elicits microglial activation. Activated microglia change their morphology, migrate to injury sites, and release tumor necrosis factor-alpha (TNF-α) and others. In this study we used a controlled fluid percussion injury model of TBI in the rat to determine whether early (4 h post-injury) or late (4 days post-injury) treatment with MLC 601, a Traditional Chinese Medicine, would affect microglial activation and improve recovery. MLC 601 was chosen for this study because its herbal component MLC 901 was beneficial in treating TBI in rats. Herein, rats with induced TBI were treated with MLC 601 (0.2-0.8 mg/kg) 1 h (early treatment) or 4 day post-injury (late treatment) and then injected once daily for consecutive 2 days. Acute neurological and motor deficits were assessed in all rats the day before and 4 days after early MLC 601 treatment. An immunofluorescence microscopy method was used to count the numbers of the cells colocalized with neuron- and apoptosis-specific markers, and the cells colocalized with microglia- and TNF-α-specific markers, in the contused brain regions 4 days post-injury. An immunohistochemistry method was used to evaluate both the number and the morphological transformation of microglia in the injured areas. It was found that early treatment with MLC 601 had better effects in reducing TBI-induced cerebral contusion than did the late therapy with MLC 601. Cerebral contusion caused by TBI was associated with neurological motor deficits, brain apoptosis, and activated microglia (e.g., microgliosis, amoeboid microglia, and microglial overexpression of TNF-α), which all were significantly attenuated by MLC 601 therapy. Our data suggest that MLC 601 is a promising agent for treatment of TBI in rats. PMID:25331680

  13. SU-E-T-33: An EPID-Based Method for Testing Absolute Leaf Position for MLC Without Backup Jaws

    SciTech Connect

    Hancock, S; Whitaker, M

    2014-06-01

    Purpose: Methods in common use for MLC leaf position QA are limited to measurements relative to an arbitrary reference position. The authors previously presented an EPID-based method for efficiently testing accuracy of leaf position relative to the mechanical isocenter for MLC with backup jaws. The purpose of this work is to extend that method to the general case of MLC without backup jaws. Methods: A pair of collimator walkout images is used to determine the location of the mechanical isocenter relative to the center of one field using a parameter called X-offset. The method allows for shift of the imager panel to cover subsets of MLC leaves within the limited field of view of the imager. For a shifted panel position, an image of three beam strips defined by a subset of MLC leaves allows determination of the position of each leaf relative to the isocenter. The location of the isocenter is determined by applying X-offset to an image of a single rectangular field obtained at that panel position. The method can also be used to test backup jaws instead of MLC leaves. A software tool was developed to efficiently analyze the images. Results: The software tool reports leaf position and deviation from nominal position, and provides visual displays to facilitate rapid qualitative interpretation. Test results using this method agree well with results using the previous method requiring backup jaws. Test results have been successfully used to recalibrate one model MLC (Elekta MLCi2™). Work in progress includes extension of the software tool to other MLC models, and quantification of reproducibility of the measurements. Conclusion: This work successfully demonstrates a method to efficiently and accurately measure MLC leaf position, or backup jaw position, relative to the mechanical isocenter of the collimator.

  14. Implementation of Hospital Examination Reservation System Using Data Mining Technique

    PubMed Central

    Cha, Hyo Soung; Yoon, Tae Sik; Ryu, Ki Chung; Shin, Il Won; Choe, Yang Hyo; Lee, Kyoung Yong; Lee, Jae Dong; Ryu, Keun Ho

    2015-01-01

    Objectives New methods for obtaining appropriate information for users have been attempted with the development of information technology and the Internet. Among such methods, the demand for systems and services that can improve patient satisfaction has increased in hospital care environments. Methods In this paper, we proposed the Hospital Exam Reservation System (HERS), which uses the data mining method. First, we focused on carrying clinical exam data and finding the optimal schedule for generating rules using the multi-examination pattern-mining algorithm. Then, HERS was applied by a rule master and recommending system with an exam log. Finally, HERS was designed as a user-friendly interface. Results HERS has been applied at the National Cancer Center in Korea since June 2014. As the number of scheduled exams increased, the time required to schedule more than a single condition decreased (from 398.67% to 168.67% and from 448.49% to 188.49%; p < 0.0001). As the number of tests increased, the difference between HERS and non-HERS increased (from 0.18 days to 0.81 days). Conclusions It was possible to expand the efficiency of HERS studies using mining technology in not only exam reservations, but also the medical environment. The proposed system based on doctor prescription removes exams that were not executed in order to improve recommendation accuracy. In addition, we expect HERS to become an effective system in various medical environments. PMID:25995961

  15. Redesigning the MCAT exam: balancing multiple perspectives.

    PubMed

    Schwartzstein, Richard M; Rosenfeld, Gary C; Hilborn, Robert; Oyewole, Saundra Herndon; Mitchell, Karen

    2013-05-01

    The authors of this commentary discuss the recently completed review of the current Medical College Admission Test (MCAT), which has been used since 1991, and describe the blueprint for the new test that will be introduced in 2015. The design of the MCAT exam reflects changes in medical education, medical science, health care delivery, and the needs of the populations served by graduates of U.S. and Canadian medical schools. The authors describe how balancing the ambitious goals for the new exam and the varying priorities of the testing program's many stakeholders made blueprint design complex. They discuss the tensions and trade-offs that characterized the design process as well as the deliberations and data that shaped the blueprint.The blueprint for the MCAT exam balances the assessment of a broad range of competencies in the natural, social, and behavioral sciences and critical analysis and reasoning skills that are essential to entering students' success in medical school. The exam will include four sections: Biological and Biochemical Foundations of Living Systems; Chemical and Physical Foundations of Biological Systems; Psychological, Social, and Biological Foundations of Behavior; and Critical Analysis and Reasoning Skills.The authors also offer recommendations for admission committees, advising them to review applicants' test scores, course work, and other academic, personal, and experiential credentials as part of a holistic admission process and in relation to their institutions' educational, scientific, clinical, and service-oriented goals. PMID:23524933

  16. Automatic Assessment of 3D Modeling Exams

    ERIC Educational Resources Information Center

    Sanna, A.; Lamberti, F.; Paravati, G.; Demartini, C.

    2012-01-01

    Computer-based assessment of exams provides teachers and students with two main benefits: fairness and effectiveness in the evaluation process. This paper proposes a fully automatic evaluation tool for the Graphic and Virtual Design (GVD) curriculum at the First School of Architecture of the Politecnico di Torino, Italy. In particular, the tool is

  17. Automatic Assessment of 3D Modeling Exams

    ERIC Educational Resources Information Center

    Sanna, A.; Lamberti, F.; Paravati, G.; Demartini, C.

    2012-01-01

    Computer-based assessment of exams provides teachers and students with two main benefits: fairness and effectiveness in the evaluation process. This paper proposes a fully automatic evaluation tool for the Graphic and Virtual Design (GVD) curriculum at the First School of Architecture of the Politecnico di Torino, Italy. In particular, the tool is…

  18. Scholars Probe Diverse Effects of Exit Exams

    ERIC Educational Resources Information Center

    Viadero, Debra

    2009-01-01

    The author reports on a study released in April 2009 that suggests that California's high school exit exams are affecting some student demographic groups more than others. The California study, which was released by the Institute for Research on Education Policy and Practice at Stanford University, is the latest in a small spate of studies…

  19. History of New York State Regents Exams

    ERIC Educational Resources Information Center

    Johnson, Carol Siri

    2009-01-01

    This paper is a brief history of the Regents subject-matter examinations and New York State's efforts to move towards educational equity. New York State was a leader in integrated curriculum and outcomes assessment in high schools for over a century. The first academic exit exam was administered in 1878 and it evolved into the controversial…

  20. New Exams for New Professional Styles

    ERIC Educational Resources Information Center

    Chaptal, Alain; Pouzard, Guy

    2004-01-01

    Recruiting professionals for schools' media resources centres needs to take into account the new dimensions of the information society. This article describes the radical reform of the very high-stakes and competitive national selection of those professionals in France. The new exam is now driven by a problem-solving approach and based on an…

  1. English-Spanish Verbatim Translation Exam.

    ERIC Educational Resources Information Center

    Stansfield, Charles W.; And Others

    The development and validation of the English-Spanish Verbatim Translation Exam (ESVTE) is described. The test is for use by the Federal Bureau of Investigation (FBI) in the selection of applicants for the positions of Language Specialist or Contract Linguist. The report is divided into eight sections. Section 1 describes the need for the test,…

  2. Undergraduate range management exam: 1999-2014

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Undergraduate Range Management Exam (URME) has been administered to undergraduate students at the Annual Meeting of the Society for Range Management since 1983, with students demonstrating their higher order learning skills and synthesis knowledge of the art and science of rangeland management. ...

  3. Introducing Standardized EFL/ESL Exams

    ERIC Educational Resources Information Center

    Laborda, Jesus Garcia

    2007-01-01

    This article presents the features, and a brief comparison, of some of the most well-known high-stakes exams. They are classified in the following fashion: tests that only include multiple-choice questions, tests that include writing and multiple-choice questions, and tests that include speaking questions. The tests reviewed are: BULATS, IELTS,…

  4. The Perils of High School Exit Exams

    ERIC Educational Resources Information Center

    Perkins-Gough, Deborah

    2005-01-01

    According to a new report by Linda Darling-Hammond and colleagues at Stanford University's School Redesign Network, state laws requiring students to pass an exit examination to obtain their high school diploma can harm students and schools. Evidence suggests that inflexible exit exam policies can reduce graduation rates (especially among minority…

  5. Do routine eye exams improve vision?

    PubMed

    Picone, Gabriel; Brown, Derek; Sloan, Frank; Lee, Paul

    2004-03-01

    We use a longitudinal national sample of Medicare claims linked to the National Long-Term Care Survey (NLTCS) to assess the productivity of routine eye examinations. Although such exams are widely recommended by professional organizations for certain populations, there is limited empirical evidence on the productivity of such care. We measure two outcomes, the ability to continue reading, and no onset of blindness or low vision, accounting for potential endogeneity of frequency of eye exams. Using instrumental variables, we find a statistically significant and beneficial effect of routine eye exams for both outcomes. Marginal effects for reading ability are large, but decline in the number of years with eye exams. Effects for blindness/low vision are smaller for the general elderly population, but larger for persons with diabetes. Instrumental variables provide a useful approach for assessing the productivity of particular interventions, particularly in situations in which randomized controlled trials are expensive or perhaps unethical and difficult to conduct over a lengthy time period. PMID:15170964

  6. SU-E-T-01: 2-D Characterization of DLG Among All MLC Leaf Pairs

    SciTech Connect

    Kumaraswamy, L; Xu, Z; Podgorsak, M; Schmitt, J; Bailey, D

    2014-06-01

    Purpose: The aim of this study is to evaluate the variation of dosimetric leaf-gap (DLG) along the travel path of each MLC leaf pair. This study evaluates whether the spatial variations in DLG could cause dose differences between TPS-calculated and measured dose. Methods: The 6MV DLG values were measured for all leaf pairs in the direction of leaf motion using a 2-D diode array and 0.6cc ion chamber. These measurements were performed on two Varian Linacs, employing the Millennium 120-leaf MLC and a 2-D-DLG variation map was created via in-house software. Several test plans were created with sweeping MLC fields using constant gaps from 2mm to 10mm and corrected for 2-D variation utilizing in-house software. Measurements were performed utilizing the MapCHECK at 5.0cm depth for plans with and without the 2-D DLG correction and compared to the TPS calculated dose via gamma analysis (3%/3mm). Results: The measured DLGs for the middle 40 MLC leaf pairs (0.5cm width) were very similar along the central superior-inferior axis, with maximum variation of 0.2mm. The outer 20 MLC leaf pairs (1.0cm width) have DLG values from 0.32mm (mean) to 0.65mm (maximum) lower than the central leaf-pair, depending on off-axis distance. Gamma pass rates for the 2mm, 4mm, and 6mm sweep plans increased by 23.2%, 28.7%, and 26.0% respectively using the 2-D-DLG correction. The most improved dose points occur in areas modulated by the 1.0cm leaf-pairs. The gamma pass rate for the 10mm sweep plan increased by only 7.7%, indicating that the 2D variation becomes less significant for dynamic plans with larger MLC gaps. Conclusion: Fluences residing significantly off-axis with narrow sweeping gaps may exhibit significant variations from planned dose due to large differences between the true DLG exhibited by the 1.0cm leaf-pairs versus the constant DLG value utilized by the TPS for dose calculation.

  7. EPID-based verification of the MLC performance for dynamic IMRT and VMAT

    SciTech Connect

    Rowshanfarzad, Pejman; Sabet, Mahsheed; Barnes, Michael P.; O'Connor, Daryl J.; Greer, Peter B.

    2012-10-15

    Purpose: In advanced radiotherapy treatments such as intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), verification of the performance of the multileaf collimator (MLC) is an essential part of the linac QA program. The purpose of this study is to use the existing measurement methods for geometric QA of the MLCs and extend them to more comprehensive evaluation techniques, and to develop dedicated robust algorithms to quantitatively investigate the MLC performance in a fast, accurate, and efficient manner. Methods: The behavior of leaves was investigated in the step-and-shoot mode by the analysis of integrated electronic portal imaging device (EPID) images acquired during picket fence tests at fixed gantry angles and arc delivery. The MLC was also studied in dynamic mode by the analysis of cine EPID images of a sliding gap pattern delivered in a variety of conditions including different leaf speeds, deliveries at fixed gantry angles or in arc mode, and changing the direction of leaf motion. The accuracy of the method was tested by detection of the intentionally inserted errors in the delivery patterns. Results: The algorithm developed for the picket fence analysis was able to find each individual leaf position, gap width, and leaf bank skewness in addition to the deviations from expected leaf positions with respect to the beam central axis with sub-pixel accuracy. For the three tested linacs over a period of 5 months, the maximum change in the gap width was 0.5 mm, the maximum deviation from the expected leaf positions was 0.1 mm and the MLC skewness was up to 0.2 Degree-Sign . The algorithm developed for the sliding gap analysis could determine the velocity and acceleration/deceleration of each individual leaf as well as the gap width. There was a slight decrease in the accuracy of leaf performance with increasing leaf speeds. The analysis results were presented through several graphs. The accuracy of the method was assessed as 0.01 mm for both the gap size and peak position determination. Conclusions: This study provides fast, easy, and accurate test methods for routine QA of the MLC performance and helps in faster troubleshooting of MLC problems in both IMRT and VMAT treatments.

  8. Brushed permanent magnet DC MLC motor operation in an external magnetic field

    SciTech Connect

    Yun, J.; St Aubin, J.; Rathee, S.; Fallone, B. G.

    2010-05-15

    Purpose: Linac-MR systems for real-time image-guided radiotherapy will utilize the multileaf collimators (MLCs) to perform conformal radiotherapy and tumor tracking. The MLCs would be exposed to the external fringe magnetic fields of the linac-MR hybrid systems. Therefore, an experimental investigation of the effect of an external magnetic field on the brushed permanent magnet DC motors used in some MLC systems was performed. Methods: The changes in motor speed and current were measured for varying external magnetic field strengths up to 2000 G generated by an EEV electromagnet. These changes in motor characteristics were measured for three orientations of the motor in the external magnetic field, mimicking changes in motor orientations due to installation and/or collimator rotations. In addition, the functionality of the associated magnetic motor encoder was tested. The tested motors are used with the Varian 120 leaf Millennium MLC (Maxon Motor half leaf and full leaf motors) and the Varian 52 leaf MKII MLC (MicroMo Electronics leaf motor) including a carriage motor (MicroMo Electronics). Results: In most cases, the magnetic encoder of the motors failed prior to any damage to the gearbox or the permanent magnet motor itself. This sets an upper limit of the external magnetic field strength on the motor function. The measured limits of the external magnetic fields were found to vary by the motor type. The leaf motor used with a Varian 52 leaf MKII MLC system tolerated up to 450{+-}10 G. The carriage motor tolerated up to 2000{+-}10 G field. The motors used with the Varian 120 leaf Millennium MLC system were found to tolerate a maximum of 600{+-}10 G. Conclusions: The current Varian MLC system motors can be used for real-time image-guided radiotherapy coupled to a linac-MR system, provided the fringe magnetic fields at their locations are below the determined tolerance levels. With the fringe magnetic fields of linac-MR systems expected to be larger than the tolerance levels determined, some form of magnetic shielding would be required.

  9. Monte Carlo based beam model using a photon MLC for modulated electron radiotherapy

    SciTech Connect

    Henzen, D. Manser, P.; Frei, D.; Volken, W.; Born, E. J.; Vetterli, D.; Chatelain, C.; Fix, M. K.; Neuenschwander, H.; Stampanoni, M. F. M.

    2014-02-15

    Purpose: Modulated electron radiotherapy (MERT) promises sparing of organs at risk for certain tumor sites. Any implementation of MERT treatment planning requires an accurate beam model. The aim of this work is the development of a beam model which reconstructs electron fields shaped using the Millennium photon multileaf collimator (MLC) (Varian Medical Systems, Inc., Palo Alto, CA) for a Varian linear accelerator (linac). Methods: This beam model is divided into an analytical part (two photon and two electron sources) and a Monte Carlo (MC) transport through the MLC. For dose calculation purposes the beam model has been coupled with a macro MC dose calculation algorithm. The commissioning process requires a set of measurements and precalculated MC input. The beam model has been commissioned at a source to surface distance of 70 cm for a Clinac 23EX (Varian Medical Systems, Inc., Palo Alto, CA) and a TrueBeam linac (Varian Medical Systems, Inc., Palo Alto, CA). For validation purposes, measured and calculated depth dose curves and dose profiles are compared for four different MLC shaped electron fields and all available energies. Furthermore, a measured two-dimensional dose distribution for patched segments consisting of three 18 MeV segments, three 12 MeV segments, and a 9 MeV segment is compared with corresponding dose calculations. Finally, measured and calculated two-dimensional dose distributions are compared for a circular segment encompassed with a C-shaped segment. Results: For 15 × 34, 5 × 5, and 2 × 2 cm{sup 2} fields differences between water phantom measurements and calculations using the beam model coupled with the macro MC dose calculation algorithm are generally within 2% of the maximal dose value or 2 mm distance to agreement (DTA) for all electron beam energies. For a more complex MLC pattern, differences between measurements and calculations are generally within 3% of the maximal dose value or 3 mm DTA for all electron beam energies. For the two-dimensional dose comparisons, the differences between calculations and measurements are generally within 2% of the maximal dose value or 2 mm DTA. Conclusions : The results of the dose comparisons suggest that the developed beam model is suitable to accurately reconstruct photon MLC shaped electron beams for a Clinac 23EX and a TrueBeam linac. Hence, in future work the beam model will be utilized to investigate the possibilities of MERT using the photon MLC to shape electron beams.

  10. SU-E-T-430: Modeling MLC Leaf End in 2D for Sliding Window IMRT and Arc Therapy

    SciTech Connect

    Liang, X; Zhu, T

    2014-06-01

    Purpose: To develop a 2D geometric model for MLC accounting for leaf end dose leakage for dynamic IMRT and Rapidarc therapy. Methods: Leaf-end dose leakage is one of the problems for MLC dose calculation and modeling. Dosimetric leaf gap used to model the MLC and to count for leakage in dose calculation, but may not be accurate for smaller leaf gaps. We propose another geometric modeling method to compensate for the MLC round-shape leaf ends dose leakage, and improve the accuracy of dose calculation and dose verification. A triangular function is used to geometrically model the MLC leaf end leakage in the leaf motion direction, and a step function is used in the perpendicular direction. Dose measurements with different leaf gap, different window width, and different window height were conducted, and the results were used to fit the analytical model to get the model parameters. Results: Analytical models have been obtained for stop-and-shoot and dynamic modes for MLC motion. Parameters a=0.4, lw'=5.0 mm for 6X and a=0.54, lw'=4.1 mm for 15x were obtained from the fitting process. The proposed MLC leaf end model improves the dose profile at the two ends of the sliding window opening. This improvement is especially significant for smaller sliding window openings, which are commonly used for highly modulated IMRT plans and arc therapy plans. Conclusion: This work models the MLC round leaf end shape and movement pattern for IMRT dose calculation. The theory, as well as the results in this work provides a useful tool for photon beam IMRT dose calculation and verification.

  11. On the suitability of Elekta’s Agility 160 MLC for tracked radiation delivery: closed-loop machine performance.

    PubMed

    Glitzner, M; Crijns, S P M; de Senneville, B Denis; Lagendijk, J J W; Raaymakers, B W

    2015-03-01

    For motion adaptive radiotherapy, dynamic multileaf collimator tracking can be employed to reduce treatment margins by steering the beam according to the organ motion. The Elekta Agility 160 MLC has hitherto not been evaluated for its tracking suitability. Both dosimetric performance and latency are key figures and need to be assessed generically, independent of the used motion sensor. In this paper, we propose the use of harmonic functions directly fed to the MLC to determine its latency during continuous motion. Furthermore, a control variable is extracted from a camera system and fed to the MLC. Using this setup, film dosimetry and subsequent γ statistics are performed, evaluating the response when tracking (MRI)-based physiologic motion in a closed-loop. The delay attributed to the MLC itself was shown to be a minor contributor to the overall feedback chain as compared to the impact of imaging components such as MRI sequences. Delay showed a linear phase behaviour of the MLC employed in continuously dynamic applications, which enables a general MLC-characterization. Using the exemplary feedback chain, dosimetry showed a vast increase in pass rate employing γ statistics. In this early stage, the tracking performance of the Agility using the test bench yielded promising results, making the technique eligible for translation to tracking using clinical imaging modalities. PMID:25675279

  12. SU-E-T-471: Small Field Jaw/MLC Reference Data

    SciTech Connect

    Kerns, J; Alvarez, P; Followill, D; Lowenstein, J; Molineu, A; Summers, P; Kry, S

    2014-06-01

    Purpose: In recent years the need for small field data of MLCs has increased due to the use of intensity-modulated radiation (IMRT), but moreover the use of stereotactic body radiation (SBRT) has increased, which uses not simply small field sizes, but small jaw and field sizes together. Having reference data for these small fields that is reliable would be invaluable to the physics community. Our study has gathered these values and the data distributions from the Radiological Physics Center's (RPC) site visits between 1990 and the present. Methods: For all measurements, the RPC used a 25 × 25 × 25cm water phantom placed at 100cm SSD. All measurements were made with an Exradin A16 cylindrical ion chamber at an effective depth of 10 cm. A total of 42 Varian machine measurements were used to compose the data for a 6 MV beam and 5 TrueBeam 6 MV flattening filter free (FFF) beams were used for FFF data. Results: Jaw/MLC fields were measured for both 6 MV and 6 MF FFF beams with the jaws and MLCs both at the following field sizes: 6×6, 4×4, 3×3, and 2×2cm. Measurements were normalized to the 10×10 field readings (defined by the jaws and MLC). Spread in the data was minimal and demonstrates a high level of accuracy of acquired data. Conclusion: Small field Jaw/MLC reference data for Varian 6MV and 6 MV FFF beams has been analyzed and presented here, composed of the aggregation of numerous RPC site visits. Obtaining reliable small field data remains difficult, however the RPC has collected high fidelity small field Jaw/MLC data. The data are presented as a reference along with their distributions, in such a way that the physicist can act based upon their own desired agreement with the reference data.

  13. Teachers' Opinion Concerning Common Exams Administered in Elementary Schools

    ERIC Educational Resources Information Center

    Caliskan, Huseyin

    2011-01-01

    The common exams that have been administered in elementary school since 2007-2008 academic year are inter-classes mid-term evaluations. With these exams, measuring the teachers' performance as well as revealing the differences among the classes are aimed at. Therefore, evaluating these exams in terms of teachers' opinions is essentially important…

  14. Enhanced Security for Online Exams Using Group Cryptography

    ERIC Educational Resources Information Center

    Jung, I. Y.; Yeom, H. Y.

    2009-01-01

    While development of the Internet has contributed to the spread of online education, online exams have not been widely adopted. An online exam is defined here as one that takes place over the insecure Internet, and where no proctor is in the same location as the examinees. This paper proposes an enhanced secure online exam management environment…

  15. Exit Exams: Decreases or Increases the Dropout Rate

    ERIC Educational Resources Information Center

    Barnes, Teresa A.

    2009-01-01

    The purpose of this paper was to examine the impact of exit exams on the dropout rate. Data was gathered from several research articles. The most impressionable research revealed exit exams have a negative effect on minorities, especially black males. Results indicate by 2012, that exit exams in 25 states will affect 81 percent of minority high…

  16. The Effect of Announced Quizzes on Exam Performance: II

    ERIC Educational Resources Information Center

    Azorlosa, Julian L.

    2011-01-01

    I administered announced, multiple-choice quizzes to 1 of 2 sections of a Psychology of Learning class in each of 2 consecutive fall semesters. The quizzes were administered between the first and second exams which were also multiple-choice. Quizzes were discontinued after the second exam. After the second exam, students completed a questionnaire…

  17. Profile of State College Entrance Exam Policies. Idaho

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Idaho's college entrance exam standards and polices. Some of the categories presented include: (1) College entrance exam policy; (2) Purpose; (3) Major changes in college entrance exam policy since the 2009-10 school year for financial reasons; (4) Preparation state offers to students taking college…

  18. Profile of State College Entrance Exam Policies. Alabama

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Alabama's college entrance exam standards and polices. Some of the categories presented include: (1) College entrance exam policy; (2) Purpose; (3) Major changes in college entrance exam policy since the 2009-10 school year for financial reasons; (4) Preparation state offers to students taking…

  19. Profile of State College Entrance Exam Policies. Delaware

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Delaware's college entrance exam standards and polices. Some of the categories presented include: (1) College entrance exam policy; (2) Purpose; (3) Major changes in college entrance exam policy since the 2009-10 school year for financial reasons; (4) Preparation state offers to students taking…

  20. Profile of State College Entrance Exam Policies. North Dakota

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on North Dakota's college entrance exam standards and polices. Some of the categories presented include: (1) College entrance exam policy; (2) Purpose; (3) Major changes in college entrance exam policy since the 2009-10 school year for financial reasons; (4) Preparation state offers to students taking…

  1. Profile of State College Entrance Exam Policies. Maine

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Maine's college entrance exam standards and polices. Some of the categories presented include: (1) College entrance exam policy; (2) Purpose; (3) Major changes in college entrance exam policy since the 2009-10 school year for financial reasons; (4) Preparation state offers to students taking college…

  2. Profile of State College Entrance Exam Policies. Kentucky

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Kentucky's college entrance exam standards and polices. Some of the categories presented include: (1) College entrance exam policy; (2) Purpose; (3) Major changes in college entrance exam policy since the 2009-10 school year for financial reasons; (4) Preparation state offers to students taking…

  3. Profile of State College Entrance Exam Policies. Tennessee

    ERIC Educational Resources Information Center

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Tennessee's college entrance exam standards and polices. Some of the categories presented include: (1) College entrance exam policy; (2) Purpose; (3) Major changes in college entrance exam policy since the 2009-10 school year for financial reasons; (4) Preparation state offers to students taking…

  4. The Effect of Announced Quizzes on Exam Performance: Quiz Content

    ERIC Educational Resources Information Center

    Azorlosa, Julian L.

    2012-01-01

    I administered quizzes to two sections of a course named "The Psychology of Learning." There were three multiple choice exams during the semester. Quizzes were given between exam 1 and exam 2. For one section, (lecture) quizzes occurred after the material had been covered in lecture. For the other section, quizzes were based on material not yet…

  5. The Cognitive Abilities of Children: Reflections from an Entrance Exam

    ERIC Educational Resources Information Center

    Cil, Emine; Cepni, Salih

    2012-01-01

    The basic determiner for the school in which the children who completed their primary education will in at an upper education level in Turkey is the entrance exam carried out nationwide. The items of national exam, called as LDE (Level Determination Exam) which the primary education pupils (aged between 12 and 15) will participate in Turkey were…

  6. Word line program disturbance based data retention error recovery strategy for MLC NAND Flash

    NASA Astrophysics Data System (ADS)

    Ma, Haozhi; Pan, Liyang; Song, Changlai; Gao, Zhongyi; Wu, Dong; Xu, Jun

    2015-07-01

    NAND Flash has been widely used as storage solutions for portable system due to improvement on data throughput, power consumption and mechanical reliability. However, NAND Flash presents inevitable decline in reliability due to scaling down and multi-level cell (MLC) technology. High data retention error rate in highly stressed blocks causes a trend of stronger ECC deployed in system, with higher hardware overhead and spare bits cost. In this paper, a word line program disturbance (WPD) based data retention error recovery strategy, which induces extra electron injection to compensate floating gate electron leakage during long retention time, is proposed to reduce the data retention error rate and improve the retention reliability of highly scaled MLC NAND Flash memories. The proposed strategy is applied on 2×-nm MLC NAND Flash and the device one-year retention error rate after 3 K, 4 K, 5 K and 6 K P/E cycled decreases by 75.7%, 79.3%, 82.3% and 83.3%, respectively.

  7. Sample Exams And Transfer In Introductory Mechanics

    NASA Astrophysics Data System (ADS)

    Koleci, Carolann

    2005-09-01

    Why do novices use examples so extensively, no matter which subject area? Examples are often helpful because they reveal how to get from problem descriptions to theoretical re-formulations. Moreover, problem solving in semantically rich domains, like physics, requires one to translate a given problem description into theoretical concepts. We address some of the important issues of knowledge transfer, in the context of introductory mechanics, using data from an on-going sample-exam study conducted at Worcester Polytechnic Institute.

  8. Real-time tumor tracking: Automatic compensation of target motion using the Siemens 160 MLC

    SciTech Connect

    Tacke, Martin B.; Nill, Simeon; Krauss, Andreas; Oelfke, Uwe

    2010-02-15

    Purpose: Advanced high quality radiation therapy techniques such as IMRT require an accurate delivery of precisely modulated radiation fields to the target volume. Interfractional and intrafractional motion of the patient's anatomy, however, may considerably deteriorate the accuracy of the delivered dose to the planned dose distributions. In order to compensate for these potential errors, a dynamic real-time capable MLC control system was designed. Methods: The newly developed adaptive MLC control system contains specialized algorithms which are capable of continuous optimization and correction of the aperture of the MLC according to the motion of the target volume during the dose delivery. The algorithms calculate the new leaf positions based on target information provided online to the system. The algorithms were implemented in a dynamic target tracking control system designed for a Siemens 160 MLC. To assess the quality of the new target tracking system in terms of dosimetric accuracy, experiments with various types of motion patterns using different phantom setups were performed. The phantoms were equipped with radiochromic films placed between solid water slabs. Dosimetric results of exemplary deliveries to moving targets with and without dynamic MLC tracking applied were compared in terms of the gamma criterion to the reference dose delivered to a static phantom. Results: Our measurements indicated that dose errors for clinically relevant two-dimensional target motion can be compensated by the new control system during the dose delivery of open fields. For a clinical IMRT dose distribution, the gamma success rate was increased from 19% to 77% using the new tracking system. Similar improvements were achieved for the delivery of a complete IMRT treatment fraction to a moving lung phantom. However, dosimetric accuracy was limited by the system's latency of 400 ms and the finite leaf width of 5 mm in the isocenter plane. Conclusions: Different experimental setups representing different target tracking scenarios proved that the tracking concept, the new algorithms and the dynamic control system make it possible to effectively compensate for dose errors due to target motion in real-time. These early results indicate that the method is suited to increasing the accuracy and the quality of the treatment delivery for the irradiation of moving tumors.

  9. Physics exam preparation: A comparison of three methods

    NASA Astrophysics Data System (ADS)

    Fakcharoenphol, Witat; Stelzer, Timothy

    2014-06-01

    In this clinical study on helping students prepare for an exam, we compared three different treatments. All students were asked to take a practice exam. One group was then given worked-out solutions for that exam, another group was given the solutions and targeted exercises to do as homework based on the result of their practice exam, and the third group was given the solutions, homework, and also an hour of one-on-one tutoring. Participants from all three conditions significantly outperformed the control group on the midterm exam. However, participants that had one-on-one tutoring did not outperform the other two participant groups.

  10. Treatment plan comparison between helical tomotherapy and MLC-based IMRT using radiobiological measures

    NASA Astrophysics Data System (ADS)

    Mavroidis, Panayiotis; Costa Ferreira, Brigida; Shi, Chengyu; Lind, Bengt K.; Papanikolaou, Nikos

    2007-07-01

    The rapid implementation of advanced treatment planning and delivery technologies for radiation therapy has brought new challenges in evaluating the most effective treatment modality. Intensity-modulated radiotherapy (IMRT) using multi-leaf collimators (MLC) and helical tomotherapy (HT) are becoming popular modes of treatment delivery and their application and effectiveness continues to be investigated. Presently, there are several treatment planning systems (TPS) that can generate and optimize IMRT plans based on user-defined objective functions for the internal target volume (ITV) and organs at risk (OAR). However, the radiobiological parameters of the different tumours and normal tissues are typically not taken into account during dose prescription and optimization of a treatment plan or during plan evaluation. The suitability of a treatment plan is typically decided based on dosimetric criteria such as dose-volume histograms (DVH), maximum, minimum, mean and standard deviation of the dose distribution. For a more comprehensive treatment plan evaluation, the biologically effective uniform dose ({\\bar{\\bar{D}}}) is applied together with the complication-free tumour control probability (P+). Its utilization is demonstrated using three clinical cases that were planned with two different forms of IMRT. In this study, three different cancer types at different anatomical sites were investigated: head and neck, lung and prostate cancers. For each cancer type, a linac MLC-based step-and-shoot IMRT plan and a HT plan were developed. The MLC-based IMRT treatment plans were developed on the Philips treatment-planning platform, using the Pinnacle 7.6 software release. For the tomotherapy HiArt plans, the dedicated tomotherapy treatment planning station was used, running version 2.1.2. By using {\\bar{\\bar{D}}} as the common prescription point of the treatment plans and plotting the tissue response probabilities versus {\\bar{\\bar{D}}} for a range of prescription doses, a number of plan trials can be compared based on radiobiological measures. The applied plan evaluation method shows that in the head and neck cancer case the HT treatment gives better results than MLC-based IMRT in terms of expected clinical outcome (P+ of 62.2% and 46.0%, {\\bar{\\bar{D}}} to the ITV of 72.3 Gy and 70.7 Gy, respectively). In the lung cancer and prostate cancer cases, the MLC-based IMRT plans are better over the clinically useful dose prescription range. For the lung cancer case, the HT and MLC-based IMRT plans give a P+ of 66.9% and 72.9%, {\\bar{\\bar{D}}} to the ITV of 64.0 Gy and 66.9 Gy, respectively. Similarly, for the prostate cancer case, the two radiation modalities give a P+ of 68.7% and 72.2%, {\\bar{\\bar{D}}} to the ITV of 86.0 Gy and 85.9 Gy, respectively. If a higher risk of complications (higher than 5%) could be allowed, the complication-free tumour control could increase by over 40%, 2% and 30% compared to the initial dose prescription for the three cancer cases, respectively. Both MLC-based IMRT and HT can encompass the often-large ITV required while they minimize the volume of the organs at risk receiving high doses. Radiobiological evaluation of treatment plans may provide an improved correlation of the delivered treatment with the clinical outcome by taking into account the dose-response characteristics of the irradiated targets and normal tissues. There may exist clinical cases, which may look dosimetrically similar but in radiobiological terms may be quite different. In such situations, traditional dose-based evaluation tools can be complemented by the use of P_ +{-}{\\bar{\\bar{D}}} diagrams to effectively evaluate and compare treatment plans.

  11. Mlc of Thermus thermophilus: a Glucose-Specific Regulator for a Glucose/Mannose ABC Transporter in the Absence of the Phosphotransferase System

    PubMed Central

    Chevance, Fabienne F. V.; Erhardt, Marc; Lengsfeld, Christina; Lee, Sung-Jae; Boos, Winfried

    2006-01-01

    We report the presence of Mlc in a thermophilic bacterium. Mlc is known as a global regulator of sugar metabolism in gram-negative enteric bacteria that is controlled by sequestration to a glucose-transporting EIIGlc of the phosphotransferase system (PTS). Since thermophilic bacteria do not possess PTS, Mlc in Thermus thermophilus must be differently controlled. DNA sequence alignments between Mlc from T. thermophilus (MlcTth) and Mlc from E. coli (MlcEco) revealed that MlcTth conserved five residues of the glucose-binding motif of glucokinases. Here we show that MlcTth is not a glucokinase but is indeed able to bind glucose (KD = 20 ?M), unlike MlcEco. We found that mlc of T. thermophilus is the first gene within an operon encoding an ABC transporter for glucose and mannose, including a glucose/mannose-binding protein and two permeases. malK1, encoding the cognate ATP-hydrolyzing subunit, is located elsewhere on the chromosome. The system transports glucose at 70C with a Km of 0.15 ?M and a Vmax of 4.22 nmol per min per ml at an optical density (OD) of 1. MlcTth negatively regulates itself and the entire glucose/mannose ABC transport system operon but not malK1, with glucose acting as an inducer. MalK1 is shared with the ABC transporter for trehalose, maltose, sucrose, and palatinose (TMSP). Mutants lacking malK1 do not transport either glucose or maltose. The TMSP transporter is also able to transport glucose with a Km of 1.4 ?M and a Vmax of 7.6 nmol per min per ml at an OD of 1, but it does not transport mannose. PMID:16952948

  12. SU-E-T-506: Dosimetric Verification of Photon MLC Delivered Electron Fields for Implementing MERT On An Artiste Linac

    SciTech Connect

    Jin, L; Eldib, A; Li, J; Wang, L; Ma, C; Fan, J

    2014-06-01

    Purpose: To verify the dose accuracy of photon MLC delivered electron fields for implementing energy-intensity modulated electron radiotherapy (MERT) on an Artiste linac. Methods: It was proposed to deliver MERT on an Artiste linac at a short SSD (60 cm) to reduce beam penumbra caused by electron scatters. An in-house developed Monte Carlo (MC)-based dose calculation/optimization planning code was used for treatment planning. Our previous study showed that the measured dose distribution of a breast plan showed good agreement with the calculations in low-medium dose regions while the differences in high dose regions were outstanding. A continuous work found that the discrepancy is mainly caused by improper modeling in MC for the single focused MLC in the Artiste which was simplified as double focused in the previous MC simulations. With this remodeled MLC in the calculations, an energy-intensity modulated electron plan using 6, 9, 12 and 15 MeV was generated for a breast treatment on a breast phantom at a 60 cm SSD and recalculated regarding a solid water phantom. For a test study, four of MLC segments (each with a different energy) generated in the plan were delivered to the phantom and a film measurement was performed at the depth of 2 cm. The measured 2D dose distribution was then compared with calculations. Results: For composite doses of the four segments, measured 2D dose distributions overall agree well with the calculations (3mm/3%) in most area. The separate measurement for a single MLC segment for each of energies also showed the consistence with the calculations. Conclusion: After remodeling MLC in the MC calculations, the measured dose distribution for a subset of MLC segments from a MERT plan showed good agreement. Further detailed verification for the full plan will be the work in the next step.

  13. Distinct gene expression patterns in skeletal and cardiac muscle are dependent on common regulatory sequences in the MLC1/3 locus.

    PubMed Central

    McGrew, M J; Bogdanova, N; Hasegawa, K; Hughes, S H; Kitsis, R N; Rosenthal, N

    1996-01-01

    The myosin light-chain 1/3 locus (MLC1/3) is regulated by two promoters and a downstream enhancer element which produce two protein isoforms in fast skeletal muscle at distinct stages of mouse embryogenesis. We have analyzed the expression of transcripts from the internal MLC3 promoter and determined that it is also expressed in the atria of the heart. Expression from the MLC3 promoter in these striated muscle lineages is differentially regulated during development. In transgenic mice, the MLC3 promoter is responsible for cardiac-specific reporter gene expression while the downstream enhancer augments expression in skeletal muscle. Examination of the methylation status of endogenous and transgenic promoter and enhancer elements indicates that the internal promoter is not regulated in a manner similar to that of the MLC1 promoter or the downstream enhancer. A GATA protein consensus sequence in the proximal MLC3 promoter but not the MLC1 promoter binds with high affinity to GATA-4, a cardiac muscle- and gut-specific transcription factor. Mutation of either the MEF2 or GATA motifs in the MLC3 promoter attenuates its activity in both heart and skeletal muscles, demonstrating that MLC3 expression in these two diverse muscle types is dependent on common regulatory elements. PMID:8754853

  14. MEGALENCEPHALIC LEUKOENCEPHALOPATHY WITH SUBCORTICAL CYSTS WITH HOMOZYGOUS MUTATION (C.448DELC, P.LEU150 SER FSX11) ON EXON 6 OF MLC1 GENE.

    PubMed

    Soysal, Z; Okur, M; Eroz, R; Gun, E; Kocabay, K; Besir, F H

    2015-01-01

    MLC or Van der Knaap disease is a rare entity, a rare and genetically heterogeneous cerebral white matter disease. It is characterized by the presence of macrocephaly, epilepsy and a slowly progressive spastic cerebellar syndrome. It is an autosomal recessive disease caused from mutations of MLC1 gene. In the current case report, a case with MLC who had a homozygous mutation (c.448delC, p.Leul50 ser fsX11) on exon 6 of MLC1 gene is presented. PMID:26349194

  15. Development and evaluation of aperture-based complexity metrics using film and EPID measurements of static MLC openings

    SciTech Connect

    Götstedt, Julia; Karlsson Hauer, Anna; Bäck, Anna

    2015-07-15

    Purpose: Complexity metrics have been suggested as a complement to measurement-based quality assurance for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). However, these metrics have not yet been sufficiently validated. This study develops and evaluates new aperture-based complexity metrics in the context of static multileaf collimator (MLC) openings and compares them to previously published metrics. Methods: This study develops the converted aperture metric and the edge area metric. The converted aperture metric is based on small and irregular parts within the MLC opening that are quantified as measured distances between MLC leaves. The edge area metric is based on the relative size of the region around the edges defined by the MLC. Another metric suggested in this study is the circumference/area ratio. Earlier defined aperture-based complexity metrics—the modulation complexity score, the edge metric, the ratio monitor units (MU)/Gy, the aperture area, and the aperture irregularity—are compared to the newly proposed metrics. A set of small and irregular static MLC openings are created which simulate individual IMRT/VMAT control points of various complexities. These are measured with both an amorphous silicon electronic portal imaging device and EBT3 film. The differences between calculated and measured dose distributions are evaluated using a pixel-by-pixel comparison with two global dose difference criteria of 3% and 5%. The extent of the dose differences, expressed in terms of pass rate, is used as a measure of the complexity of the MLC openings and used for the evaluation of the metrics compared in this study. The different complexity scores are calculated for each created static MLC opening. The correlation between the calculated complexity scores and the extent of the dose differences (pass rate) are analyzed in scatter plots and using Pearson’s r-values. Results: The complexity scores calculated by the edge area metric, converted aperture metric, circumference/area ratio, edge metric, and MU/Gy ratio show good linear correlation to the complexity of the MLC openings, expressed as the 5% dose difference pass rate, with Pearson’s r-values of −0.94, −0.88, −0.84, −0.89, and −0.82, respectively. The overall trends for the 3% and 5% dose difference evaluations are similar. Conclusions: New complexity metrics are developed. The calculated scores correlate to the complexity of the created static MLC openings. The complexity of the MLC opening is dependent on the penumbra region relative to the area of the opening. The aperture-based complexity metrics that combined either the distances between the MLC leaves or the MLC opening circumference with the aperture area show the best correlation with the complexity of the static MLC openings.

  16. SU-E-T-583: Optimizing the MLC Model Parameters for IMRT in the RayStation Treatment Planning System

    SciTech Connect

    Chen, S; Yi, B; Xu, H; Yang, X; Prado, K; D'Souza, W

    2014-06-01

    Purpose: To optimize the MLC model parameters for IMRT in the RayStation v.4.0 planning system and for a Varian C-series Linac with a 120-leaf Millennium MLC. Methods: The RayStation treatment planning system models rounded leaf-end MLC with the following parameters: average transmission, leaf-tip width, tongue-and-groove, and position offset. The position offset was provided by Varian. The leaf-tip width was iteratively evaluated by comparing computed and measured transverse dose profiles of MLC-defined fields at dmax in water. The profile comparison was also used to verify the MLC position offset. The transmission factor and leaf tongue width were derived iteratively by optimizing five clinical patient IMRT QA Results: brain, lung, pancreas, head-and-neck (HN), and prostate. The HN and prostate cases involved splitting fields. Verifications were performed with Mapcheck2 measurements and Monte Carlo calculations. Finally, the MLC model was validated using five test IMRT cases from the AAPM TG119 report. Absolute gamma analyses (3mm/3% and 2mm/2%) were applied. In addition, computed output factors for MLC-defined small fields (2×2, 3×3, 4×4, 6×6cm) of both 6MV and 18MV were compared to those measured by the Radiological Physics Center (RPC). Results: Both 6MV and 18MV models were determined to have the same MLC parameters: 2.5% transmission, tongue-and-groove 0.05cm, and leaftip 0.3cm. IMRT QA analysis for five cases in TG119 resulted in a 100% passing rate with 3mm/3% gamma analysis for 6MV, and >97.5% for 18MV. With 2mm/2% gamma analysis, the passing rate was >94.6% for 6MV and >90.9% for 18MV. The difference between computed output factors in RayStation and RPC measurements was less than 2% for all MLCdefined fields, which meets the RPC's acceptance criterion. Conclusion: The rounded leaf-end MLC model in RayStation 4.0 planning system was verified and IMRT commissioning was clinically acceptable. The IMRT commissioning was well validated using guidance from the AAPMTG119 protocol.

  17. Monitoring daily MLC positional errors using trajectory log files and EPID measurements for IMRT and VMAT deliveries

    NASA Astrophysics Data System (ADS)

    Agnew, A.; Agnew, C. E.; Grattan, M. W. D.; Hounsell, A. R.; McGarry, C. K.

    2014-05-01

    This work investigated the differences between multileaf collimator (MLC) positioning accuracy determined using either log files or electronic portal imaging devices (EPID) and then assessed the possibility of reducing patient specific quality control (QC) via phantom-less methodologies. In-house software was developed, and validated, to track MLC positional accuracy with the rotational and static gantry picket fence tests using an integrated electronic portal image. This software was used to monitor MLC daily performance over a 1 year period for two Varian TrueBeam linear accelerators, with the results directly compared with MLC positions determined using leaf trajectory log files. This software was validated by introducing known shifts and collimator errors. Skewness of the MLCs was found to be 0.03 ± 0.06° (mean ±1 standard deviation (SD)) and was dependent on whether the collimator was rotated manually or automatically. Trajectory log files, analysed using in-house software, showed average MLC positioning errors with a magnitude of 0.004 ± 0.003 mm (rotational) and 0.004 ± 0.011 mm (static) across two TrueBeam units over 1 year (mean ±1 SD). These ranges, as indicated by the SD, were lower than the related average MLC positioning errors of 0.000 ± 0.025 mm (rotational) and 0.000 ± 0.039 mm (static) that were obtained using the in-house EPID based software. The range of EPID measured MLC positional errors was larger due to the inherent uncertainties of the procedure. Over the duration of the study, multiple MLC positional errors were detected using the EPID based software but these same errors were not detected using the trajectory log files. This work shows the importance of increasing linac specific QC when phantom-less methodologies, such as the use of log files, are used to reduce patient specific QC. Tolerances of 0.25 mm have been created for the MLC positional errors using the EPID-based automated picket fence test. The software allows diagnosis of any specific leaf that needs repair and gives an indication as to the course of action that is required.

  18. An EPID response calculation algorithm using spatial beam characteristics of primary, head scattered and MLC transmitted radiation

    SciTech Connect

    Rosca, Florin; Zygmanski, Piotr

    2008-06-15

    We have developed an independent algorithm for the prediction of electronic portal imaging device (EPID) response. The algorithm uses a set of images [open beam, closed multileaf collimator (MLC), various fence and modified sweeping gap patterns] to separately characterize the primary and head-scatter contributions to EPID response. It also characterizes the relevant dosimetric properties of the MLC: Transmission, dosimetric gap, MLC scatter [P. Zygmansky et al., J. Appl. Clin. Med. Phys. 8(4) (2007)], inter-leaf leakage, and tongue and groove [F. Lorenz et al., Phys. Med. Biol. 52, 5985-5999 (2007)]. The primary radiation is modeled with a single Gaussian distribution defined at the target position, while the head-scatter radiation is modeled with a triple Gaussian distribution defined downstream of the target. The distances between the target and the head-scatter source, jaws, and MLC are model parameters. The scatter associated with the EPID is implicit in the model. Open beam images are predicted to within 1% of the maximum value across the image. Other MLC test patterns and intensity-modulated radiation therapy fluences are predicted to within 1.5% of the maximum value. The presented method was applied to the Varian aS500 EPID but is designed to work with any planar detector with sufficient spatial resolution.

  19. Improving IMRT-plan quality with MLC leaf position refinement post plan optimization

    SciTech Connect

    Niu Ying; Zhang Guowei; Berman, Barry L.; Parke, William C.; Yi Byongyong; Yu, Cedric X.

    2012-08-15

    Purpose: In intensity-modulated radiation therapy (IMRT) planning, reducing the pencil-beam size may lead to a significant improvement in dose conformity, but also increase the time needed for the dose calculation and plan optimization. The authors develop and evaluate a postoptimization refinement (POpR) method, which makes fine adjustments to the multileaf collimator (MLC) leaf positions after plan optimization, enhancing the spatial precision and improving the plan quality without a significant impact on the computational burden. Methods: The authors' POpR method is implemented using a commercial treatment planning system based on direct aperture optimization. After an IMRT plan is optimized using pencil beams with regular pencil-beam step size, a greedy search is conducted by looping through all of the involved MLC leaves to see if moving the MLC leaf in or out by half of a pencil-beam step size will improve the objective function value. The half-sized pencil beams, which are used for updating dose distribution in the greedy search, are derived from the existing full-sized pencil beams without need for further pencil-beam dose calculations. A benchmark phantom case and a head-and-neck (HN) case are studied for testing the authors' POpR method. Results: Using a benchmark phantom and a HN case, the authors have verified that their POpR method can be an efficient technique in the IMRT planning process. Effectiveness of POpR is confirmed by noting significant improvements in objective function values. Dosimetric benefits of POpR are comparable to those of using a finer pencil-beam size from the optimization start, but with far less computation and time. Conclusions: The POpR is a feasible and practical method to significantly improve IMRT-plan quality without compromising the planning efficiency.

  20. SU-D-18A-05: Assessing Elekta MLC Tracking Performance

    SciTech Connect

    Glitzner, M; Crijns, S; Lagendijk, J; Raaymakers, B

    2014-06-01

    Purpose: To investigate the technical feasibility of using Elekta MLCs in tracked radiotherapy, specifically to show the capability of an Agility MLC to follow model tumor trajectories using object tracking. The system performance of the MLC is to be assessed via dosimetric experiments and temporal response measures. Methods: The system observer in the tracking cascade consisted of a camera serving for this proof of concept; Images of a moving object were acquired continuously and decorrelated for the position information, which was fed forward to the RT computer controlling the MLC via an interface provided by Elekta. The 1D motion (in the direction of the leaves) was induced by a CIRS motion controller. Additionally, the aperture position was observed by means of the light field of the linac. Calculating the phase between aperture and object yielded the mean aperture lag for the current setup. The object was restricted to sinusoidal motion with a period of 10s. For dosimetry, GafChromic radiosensitive film was irradiated with a total dose of 1000MU using an aperture size of 40mm and a motion range of 30mm. Results: Object tracking can substantially reconstruct the geometric dose response of a static target. In the dynamic case, dose is smeared out into the legs of the static distribution, leading to a reduced plateau and increased FWHM of 5mm, compared to the static width of 38mm. The time-lag between object and aperture was determined to be approximately 300ms for the current set-up. Conclusion: We demonstrated a tracking experiment performed on a clinical Elekta linear accelator for the first time. Observed profile variations show the dosimetric impact of tracked delivery. The determined lag is a valuable descriptor for a future tracking cascade employing predictor filters. The performed experiments are generic and possible predecessors for future applications with MR-Linac or ultrasound probes. Conflict of interest: this project is partly funded by Elekta.

  1. Determination of the optimal tolerance for MLC positioning in sliding window and VMAT techniques

    SciTech Connect

    Hernandez, V. Abella, R.; Calvo, J. F.; Jurado-Bruggemann, D.; Sancho, I.; Carrasco, P.

    2015-04-15

    Purpose: Several authors have recommended a 2 mm tolerance for multileaf collimator (MLC) positioning in sliding window treatments. In volumetric modulated arc therapy (VMAT) treatments, however, the optimal tolerance for MLC positioning remains unknown. In this paper, the authors present the results of a multicenter study to determine the optimal tolerance for both techniques. Methods: The procedure used is based on dynalog file analysis. The study was carried out using seven Varian linear accelerators from five different centers. Dynalogs were collected from over 100 000 clinical treatments and in-house software was used to compute the number of tolerance faults as a function of the user-defined tolerance. Thus, the optimal value for this tolerance, defined as the lowest achievable value, was investigated. Results: Dynalog files accurately predict the number of tolerance faults as a function of the tolerance value, especially for low fault incidences. All MLCs behaved similarly and the Millennium120 and the HD120 models yielded comparable results. In sliding window techniques, the number of beams with an incidence of hold-offs >1% rapidly decreases for a tolerance of 1.5 mm. In VMAT techniques, the number of tolerance faults sharply drops for tolerances around 2 mm. For a tolerance of 2.5 mm, less than 0.1% of the VMAT arcs presented tolerance faults. Conclusions: Dynalog analysis provides a feasible method for investigating the optimal tolerance for MLC positioning in dynamic fields. In sliding window treatments, the tolerance of 2 mm was found to be adequate, although it can be reduced to 1.5 mm. In VMAT treatments, the typically used 5 mm tolerance is excessively high. Instead, a tolerance of 2.5 mm is recommended.

  2. Engagement with Online Pre-Exam Formative Tests Improves Exam Performance and Feedback Satisfaction

    ERIC Educational Resources Information Center

    Hope, Sheila A.; Polwart, Anthony

    2012-01-01

    The National Union of Students (NUS) National Student Experience Report identified examination feedback as an area where students had particular concerns. This finding was echoed in the authors' institution and triggered an action research project to investigate ways of improving students' perceptions of pre- and post-exam feedback. We report the…

  3. ExamFolder(R) technology integrator

    NASA Astrophysics Data System (ADS)

    Scott, David K.

    1994-10-01

    Cargo examination systems will integrate multiple sensors because single sensor systems can be defeated. Trials with multiple sensors have also resulted in both increased inspection accuracy and throughput. The traditional integration point for multiple sensor outputs is paper. Cargo inspection analysts must evaluate a file folder containing many interrelated pieces of paper within minutes. File folders with paper have proven to be an obsolete medium for complex data presentation. A computer-based system, ExamFolder Technology Integrator uses an open architecture to receive input from multiple sensors treating each input data set as a document. Documents from any sensor, even those yet to be developed, can be collected, structured, and displayed to the analyst. The documents include, but are not limited to: digital data, imagery, video and digitized voice. The system structures the documents for scrutinizing manifested cargo, shipper, shipping agent, carrier, broker, forwarder and consignee histories. This reduces pressure on the analyst for timely completion of the inspection. The ExamFolder Technology Integrator is an efficient, sensor-vendor independent, computer screen-based, cargo inspection system providing meaningful information to the cargo analyst.

  4. EXAM: A search for extragalactic antimatter

    SciTech Connect

    Crary, D.J.

    1991-01-01

    This thesis presents results from a search for extragalactic antimatter in the cosmic rays (the EXAM experiment). The reasons for undertaking a search for antimatter are given, along with various arguments that indicate that a antimatter fraction of 10{sup {minus}6} {minus} 10{sup {minus}7} in the cosmic-ray flux at earth would not be inconsistent with current antimatter limits obtained from cosmic-ray experiments or with limits set by gamma-ray observations. An experimental technique sensitive to antinuclei with charge Z near iron (Z = 26) is reviewed. This technique uses a combination of active detectors (scintillators, Cerenkov counters) and CR-39 track-etch detectors to provide a unique signature for antimatter detection at a level consistent with the flux estimates given above. This is followed by description of the implementation of this technique (the EXAM detector), along with a summary of the data analysis to date. Directions for future work are described. A detailed description of the microscope system used in the automated analysis of the CR-39 plastic is presented.

  5. The dosimetric impact of inversely optimized arc radiotherapy plan modulation for real-time dynamic MLC tracking delivery

    SciTech Connect

    Falk, Marianne; Larsson, Tobias; Keall, Paul; Chul Cho, Byung; Aznar, Marianne; Korreman, Stine; Poulsen, Per; Munck af Rosenschoeld, Per

    2012-03-15

    Purpose: Real-time dynamic multileaf collimator (MLC) tracking for management of intrafraction tumor motion can be challenging for highly modulated beams, as the leaves need to travel far to adjust for target motion perpendicular to the leaf travel direction. The plan modulation can be reduced by using a leaf position constraint (LPC) that reduces the difference in the position of adjacent MLC leaves in the plan. The purpose of this study was to investigate the impact of the LPC on the quality of inversely optimized arc radiotherapy plans and the effect of the MLC motion pattern on the dosimetric accuracy of MLC tracking delivery. Specifically, the possibility of predicting the accuracy of MLC tracking delivery based on the plan modulation was investigated. Methods: Inversely optimized arc radiotherapy plans were created on CT-data of three lung cancer patients. For each case, five plans with a single 358 deg. arc were generated with LPC priorities of 0 (no LPC), 0.25, 0.5, 0.75, and 1 (highest possible LPC), respectively. All the plans had a prescribed dose of 2 Gy x 30, used 6 MV, a maximum dose rate of 600 MU/min and a collimator angle of 45 deg. or 315 deg. To quantify the plan modulation, an average adjacent leaf distance (ALD) was calculated by averaging the mean adjacent leaf distance for each control point. The linear relationship between the plan quality [i.e., the calculated dose distributions and the number of monitor units (MU)] and the LPC was investigated, and the linear regression coefficient as well as a two tailed confidence level of 95% was used in the evaluation. The effect of the plan modulation on the performance of MLC tracking was tested by delivering the plans to a cylindrical diode array phantom moving with sinusoidal motion in the superior-inferior direction with a peak-to-peak displacement of 2 cm and a cycle time of 6 s. The delivery was adjusted to the target motion using MLC tracking, guided in real-time by an infrared optical system. The dosimetric results were evaluated using gamma index evaluation with static target measurements as reference. Results: The plan quality parameters did not depend significantly on the LPC (p {>=} 0.066), whereas the ALD depended significantly on the LPC (p < 0.001). The gamma index failure rate depended significantly on the ALD, weighted to the percentage of the beam delivered in each control point of the plan (ALD{sub w}) when MLC tracking was used (p < 0.001), but not for delivery without MLC tracking (p {>=} 0.342). The gamma index failure rate with the criteria of 2% and 2 mm was decreased from > 33.9% without MLC tracking to <31.4% (LPC 0) and <2.2% (LPC 1) with MLC tracking. Conclusions: The results indicate that the dosimetric robustness of MLC tracking delivery of an inversely optimized arc radiotherapy plan can be improved by incorporating leaf position constraints in the objective function without otherwise affecting the plan quality. The dosimetric robustness may be estimated prior to delivery by evaluating the ALD{sub w} of the plan.

  6. REGION 9 INDIAN RESERVATIONS

    EPA Science Inventory

    Polygon coverage of all Indian Reservations in US EPA Region 9 (California, Arizona and Nevada). Reservation boundaries are compiled from multiple sources and are derived from several different source scales. Information such as reservation type, primary tribe name and location...

  7. NEVADA INDIAN RESERVATIONS

    EPA Science Inventory

    Polygon coverage of all Indian Reservations in Nevada. Reservation boundaries are compiled from multiple sources and are derived from several different source scales. Information such as reservation type, primary tribe name and location source are included with the coverage. As...

  8. ARIZONA INDIAN RESERVATIONS

    EPA Science Inventory

    Polygon coverage of all Indian Reservations in Arizona. Reservation boundaries are compiled from multiple sources and are derived from several different source scales. Information such as reservation type, primary tribe name and location source are included with the coverage. A...

  9. Effect of MLC leaf position, collimator rotation angle, and gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma

    SciTech Connect

    Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie; Wei, Yuquan

    2013-07-01

    The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.

  10. SU-E-T-405: Robustness of Volumetric-Modulated Arc Therapy (VMAT) Plans to Systematic MLC Positional Errors

    SciTech Connect

    Qi, P; Xia, P

    2014-06-01

    Purpose: To evaluate the dosimetric impact of systematic MLC positional errors (PEs) on the quality of volumetric-modulated arc therapy (VMAT) plans. Methods: Five patients with head-and-neck cancer (HN) and five patients with prostate cancer were randomly chosen for this study. The clinically approved VMAT plans were designed with 2–4 coplanar arc beams with none-zero collimator angles in the Pinnacle planning system. The systematic MLC PEs of 0.5, 1.0, and 2.0 mm on both MLC banks were introduced into the original VMAT plans using an in-house program, and recalculated with the same planned Monitor Units in the Pinnacle system. For each patient, the original VMAT plans and plans with MLC PEs were evaluated according to the dose-volume histogram information and Gamma index analysis. Results: For one primary target, the ratio of V100 in the plans with 0.5, 1.0, and 2.0 mm MLC PEs to those in the clinical plans was 98.8 ± 2.2%, 97.9 ± 2.1%, 90.1 ± 9.0% for HN cases and 99.5 ± 3.2%, 98.9 ± 1.0%, 97.0 ± 2.5% for prostate cases. For all OARs, the relative difference of Dmean in all plans was less than 1.5%. With 2mm/2% criteria for Gamma analysis, the passing rates were 99.0 ± 1.5% for HN cases and 99.7 ± 0.3% for prostate cases between the planar doses from the original plans and the plans with 1.0 mm MLC errors. The corresponding Gamma passing rates dropped to 88.9 ± 5.3% for HN cases and 83.4 ± 3.2% for prostate cases when comparing planar doses from the original plans and the plans with 2.0 mm MLC errors. Conclusion: For VMAT plans, systematic MLC PEs up to 1.0 mm did not affect the plan quality in term of target coverage, OAR sparing, and Gamma analysis with 2mm/2% criteria.

  11. Assessment of MLC tracking performance during hypofractionated prostate radiotherapy using real-time dose reconstruction.

    PubMed

    Fast, M F; Kamerling, C P; Ziegenhein, P; Menten, M J; Bedford, J L; Nill, S; Oelfke, U

    2016-02-21

    By adapting to the actual patient anatomy during treatment, tracked multi-leaf collimator (MLC) treatment deliveries offer an opportunity for margin reduction and healthy tissue sparing. This is assumed to be especially relevant for hypofractionated protocols in which intrafractional motion does not easily average out. In order to confidently deliver tracked treatments with potentially reduced margins, it is necessary to monitor not only the patient anatomy but also the actually delivered dose during irradiation. In this study, we present a novel real-time online dose reconstruction tool which calculates actually delivered dose based on pre-calculated dose influence data in less than 10?ms at a rate of 25 Hz. Using this tool we investigate the impact of clinical target volume (CTV) to planning target volume (PTV) margins on CTV coverage and organ-at-risk dose. On our research linear accelerator, a set of four different CTV-to-PTV margins were tested for three patient cases subject to four different motion conditions. Based on this data, we can conclude that tracking eliminates dose cold spots which can occur in the CTV during conventional deliveries even for the smallest CTV-to-PTV margin of 1?mm. Changes of organ-at-risk dose do occur frequently during MLC tracking and are not negligible in some cases. Intrafractional dose reconstruction is expected to become an important element in any attempt of re-planning the treatment plan during the delivery based on the observed anatomy of the day. PMID:26816273

  12. Assessment of MLC tracking performance during hypofractionated prostate radiotherapy using real-time dose reconstruction

    NASA Astrophysics Data System (ADS)

    Fast, M. F.; Kamerling, C. P.; Ziegenhein, P.; Menten, M. J.; Bedford, J. L.; Nill, S.; Oelfke, U.

    2016-02-01

    By adapting to the actual patient anatomy during treatment, tracked multi-leaf collimator (MLC) treatment deliveries offer an opportunity for margin reduction and healthy tissue sparing. This is assumed to be especially relevant for hypofractionated protocols in which intrafractional motion does not easily average out. In order to confidently deliver tracked treatments with potentially reduced margins, it is necessary to monitor not only the patient anatomy but also the actually delivered dose during irradiation. In this study, we present a novel real-time online dose reconstruction tool which calculates actually delivered dose based on pre-calculated dose influence data in less than 10 ms at a rate of 25 Hz. Using this tool we investigate the impact of clinical target volume (CTV) to planning target volume (PTV) margins on CTV coverage and organ-at-risk dose. On our research linear accelerator, a set of four different CTV-to-PTV margins were tested for three patient cases subject to four different motion conditions. Based on this data, we can conclude that tracking eliminates dose cold spots which can occur in the CTV during conventional deliveries even for the smallest CTV-to-PTV margin of 1 mm. Changes of organ-at-risk dose do occur frequently during MLC tracking and are not negligible in some cases. Intrafractional dose reconstruction is expected to become an important element in any attempt of re-planning the treatment plan during the delivery based on the observed anatomy of the day.

  13. Development of a Monte Carlo model for the Brainlab microMLC.

    PubMed

    Belec, Jason; Patrocinio, Horacio; Verhaegen, Frank

    2005-03-01

    Stereotactic radiosurgery with several static conformal beams shaped by a micro multileaf collimator (microMLC) is used to treat small irregularly shaped brain lesions. Our goal is to perform Monte Carlo calculations of dose distributions for certain treatment plans as a verification tool. A dedicated microMLC component module for the BEAMnrc code was developed as part of this project and was incorporated in a model of the Varian CL2300 linear accelerator 6 MV photon beam. As an initial validation of the code, the leaf geometry was visualized by tracing particles through the component module and recording their position each time a leaf boundary was crossed. The leaf dimensions were measured and the leaf material density and interleaf air gap were chosen to match the simulated leaf leakage profiles with film measurements in a solid water phantom. A comparison between Monte Carlo calculations and measurements (diode, radiographic film) was performed for square and irregularly shaped fields incident on flat and homogeneous water phantoms. Results show that Monte Carlo calculations agree with measured dose distributions to within 2% and/or 1 mm except for field size smaller than 1.2 cm diameter where agreement is within 5% due to uncertainties in measured output factors. PMID:15798255

  14. In vitro study of cell survival following dynamic MLC intensity-modulated radiation therapy dose delivery

    SciTech Connect

    Moiseenko, Vitali; Duzenli, Cheryl; Durand, Ralph E.

    2007-04-15

    The possibility of reduced cell kill following intensity-modulated radiation therapy (IMRT) compared to conventional radiation therapy has been debated in the literature. This potential reduction in cell kill relates to prolonged treatment times typical of IMRT dose delivery and consequently increased repair of sublethal lesions. While there is some theoretical support to this reduction in cell kill published in the literature, direct experimental evidence specific to IMRT dose delivery patterns is lacking. In this study we present cell survival data for three cell lines: Chinese hamster V79 fibroblasts, human cervical carcinoma, SiHa and colon adenocarcinoma, WiDr. Cell survival was obtained for 2.1 Gy delivered as acute dose with parallel-opposed pair (POP), irradiation time 75 s, which served as a reference; regular seven-field IMRT, irradiation time 5 min; and IMRT with a break for multiple leaf collimator (MLC) re-initialization after three fields were delivered, irradiation time 10 min. An actual seven-field dynamic MLC IMRT plan for a head and neck patient was used. The IMRT plan was generated for a Varian EX or iX linear accelerator with 120 leaf Millenium MLC. Survival data were also collected for doses 1x, 2x, 3x, 4x, and 5x 2.1 Gy to establish parameters of the linear-quadratic equation describing survival following acute dose delivery. Cells were irradiated inside an acrylic cylindrical phantom specifically designed for this study. Doses from both IMRT and POP were validated using ion chamber measurements. A reproducible increase in cell survival was observed following IMRT dose delivery. This increase varied from small for V79, with a surviving fraction of 0.8326 following POP vs 0.8420 following uninterrupted IMRT, to very pronounced for SiHa, with a surviving fraction of 0.3903 following POP vs 0.5330 for uninterrupted IMRT. When compared to IMRT or IMRT with a break for MLC initialization, cell survival following acute dose delivery was significantly different, p<0.05, in three out of six cases. In contrast, when cell survival following IMRT was compared to that following IMRT with a break for MLC initialization the difference was always statistically insignificant. When projected to a 30 fraction treatment, dose deficit to bring cell survival to the same value as in POP was calculated as 4.1, 24.9, and 31.1 Gy for V79, WiDr, and SiHa cell lines, respectively. The dose deficit did not relate to the {alpha}/{beta} ratio obtained in this study for the three cell lines. Clinical data do not show reduction in local control following IMRT. Possible reasons for this are discussed. The obtained data set can serve as a test data set for models designed to explore the effect of dose delivery prolongation/fractionation in IMRT on radiation therapy outcome.

  15. Biological consequences of MLC calibration errors in IMRT delivery and QA

    SciTech Connect

    Moiseenko, Vitali; LaPointe, Vincent; James, Kerry; Yin Lingshu; Liu, Mitchell; Pawlicki, Todd

    2012-04-15

    Purpose: The purpose of this work is threefold: (1) to explore biological consequences of the multileaf collimator (MLC) calibration errors in intensity modulated radiotherapy (IMRT) of prostate and head and neck cancers, (2) to determine levels of planning target volume (PTV) and normal tissue under- or overdose flagged with clinically used QA action limits, and (3) to provide biologically based input for MLC QA and IMRT QA action limits. Methods: Ten consecutive prostate IMRT cases and ten consecutive head and neck IMRT cases were used. Systematic MLC offsets (i.e., calibration error) were introduced for each control point of the plan separately for X1 and X2 leaf banks. Offsets were from - 2 to 2 mm with a 0.5 mm increment. The modified files were imported into the planning system for forward dose recalculation. The original plan served as the reference. The generalized equivalent uniform dose (gEUD) was used as the biological index for the targets, rectum, parotid glands, brainstem, and spinal cord. Each plan was recalculated on a CT scan of a 27 cm diameter cylindrical phantom with a contoured 0.6 cc ion chamber. Dose to ion chamber and 3D gamma analysis were compared to the reference plan. QA pass criteria: (1) at least 95% of voxels with a dose cutoff of 50% of maximum dose have to pass at 3 mm/3% and (2) dose to chamber within 2% of the reference dose. Results: For prostate cases, differences in PTV and rectum gEUD greater than 2% were identified. However, a larger proportion of plans leading to greater than 2% difference in prostate PTV gEUD passed the ion chamber QA but not 3D gamma QA. A similar trend was found for the rectum gEUD. For head and neck IMRT, the QA pass criteria flagged plans leading to greater than 4% differences in PTV gEUD and greater than 5% differences in the maximum dose to brainstem. If pass criteria were relaxed to 90% for gamma and 3% for ion chamber QA, plans leading to a 5% difference in PTV gEUD and a 5%-8% difference in brainstem maximum dose would likely pass IMRT QA. A larger proportion of head and neck plans with greater than 2% PTV gEUD difference passed 3D gamma QA compared to ion chamber QA. Conclusions: For low modulation plans, there is a better chance to catch MLC calibration errors with 3D gamma QA rather than ion chamber QA. Conversely, for high modulation plans, there is a better chance to catch MLC calibration errors with ion chamber QA rather than with 3D gamma QA. Ion chamber and 3D gamma analysis IMRT QA can detect greater than 2% change in gEUD for PTVs and critical structures for low modulation treatment plans. For high modulation treatment plans, ion chamber and 3D gamma analysis can detect greater than 2% change in gEUD for PTVs and a 5% change in critical structure gEUD since either QA methods passes the QA criteria. For gEUD changes less than those listed above, either QA method has the same proportion of passing rate.

  16. The Red Effect, Anxiety, and Exam Performance: A Multistudy Examination

    ERIC Educational Resources Information Center

    Smajic, Adnan; Merritt, Stephanie; Banister, Christina; Blinebry, Amanda

    2014-01-01

    Laboratory studies have established a negative relationship between the color red and academic performance. This research examined whether this effect would generalize to classroom performance and whether anxiety and negative affect might mediate the effect. In two studies, students taking classroom exams were randomly assigned an exam color. We…

  17. Commitment to Study as a Technique to Improve Exam Performance.

    ERIC Educational Resources Information Center

    Leeming, Frank C.

    1997-01-01

    Reports on a technique that could increase study time by reducing procrastination. Randomly selected college students (N=197) made written commitments to study for an exam. Students in the commitment condition reported significantly more study time than did students in a control group; they also performed significantly better on the exam. (RJM)

  18. Automating Exams for a Statistics Course: II. A Case Study.

    ERIC Educational Resources Information Center

    Michener, R. Dean; And Others

    A specific application of the process of automating exams for any introductory statistics course is described. The process of automating exams was accomplished by using the Statistical Test Item Collection System (STICS). This system was first used to select a set of questions based on course requirements established in advance; afterward, STICS

  19. Gender Differences in STEM Related Advanced Placement Exams

    ERIC Educational Resources Information Center

    Morris, Jill B.

    2013-01-01

    Purpose: The purpose of this study was to examine differences between boys and girls in their performance on STEM related AP exams. Specifically, gender differences were examined for the following STEM related AP exams: Calculus AB, Calculus BC, Physics B, Physics C: Electricity and Magnetism, Physics C: Mechanics, Chemistry, and Computer Science…

  20. Preparing Students to Take SOA/CAS Exam FM/2

    ERIC Educational Resources Information Center

    Marchand, Richard J.

    2014-01-01

    This paper provides suggestions for preparing students to take the actuarial examination on financial mathematics, SOA/CAS Exam FM/2. It is based on current practices employed at Slippery Rock University, a small public liberal arts university. Detailed descriptions of our Theory of Interest course and subsequent Exam FM/2 prep course are provided…

  1. Exit Exams Face Pinch in Common-Core Push

    ERIC Educational Resources Information Center

    Ujifusa, Andrew

    2012-01-01

    With many states crafting assessments based on the common-core standards--and an increasing emphasis on college and career readiness--some are rethinking the kind of tests high school students must pass to graduate, or whether to use such exit exams at all. Twenty-five states, enrolling a total of 34.1 million students, make exit exams a…

  2. An Expanded Framework for Analyzing General Chemistry Exams

    ERIC Educational Resources Information Center

    Smith, K. Christopher; Nakhleh, Mary B.; Bretz, Stacey Lowery

    2010-01-01

    This paper describes an expanded framework to aid chemical educators in constructing exams for their courses. The framework has three primary levels: definition, algorithmic, and conceptual. These primary levels have often been used in chemical education research to analyze and describe exam questions, but in this study the definition,

  3. Two Examples of Group Exams from Communication and Engineering

    ERIC Educational Resources Information Center

    Sandell, Karin L.; Welch, Lonnie

    2004-01-01

    The two models for group exams described here employ these exams as both a formative strategy for assessing student understanding of key course material and preparing students for further class activities and a summative strategy for evaluating student learning and assigning grades.

  4. High School Exit Exams and "Mis"measurement

    ERIC Educational Resources Information Center

    Tienken, Christopher H.

    2011-01-01

    Test score validity takes center stage in the debate over the use of high school exit exams. Scant literature addresses the amount of conditional standard error of measurement (CSEM) present in individual student results on high school exit exams. The purpose of this study is to fill a void in the literature and add a national review of the CSEM,…

  5. Problematizing High School Certificate Exam in Pakistan: A Washback Perspective

    ERIC Educational Resources Information Center

    Jilani, Raana

    2009-01-01

    This paper describes and evaluates the Higher-Secondary School Certificate (HSC) exam in Pakistan that has been in place in its present form for more than thirty years. The author recounts her experience as a teacher of English in a representative high school in Pakistan and, reflecting on the impact of high school public exam, she argues that the…

  6. Should I Give the Exam before or after the Break?

    ERIC Educational Resources Information Center

    O'Connor, Kevin J.

    2014-01-01

    This study was designed to help faculty make decisions about when to administer an exam in relation to an in-semester break. Students in multiple sections of an undergraduate educational psychology class were assigned to take an exam either before or after a scheduled 5-day break (Thursday-Monday). A multiple regression analysis revealed the break…

  7. OK State Profile. Oklahoma: End-of-Instruction (EOI) Exams

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper provides information about Oklahoma's End-of-Instruction Exams. The purpose of the exam is to: (1) Determine prospective high school graduates' knowledge and skill levels relative to those needed for entry-level employment aligned to the American Diploma Project (ADP) benchmarks; (2) Determine prospective high school graduates'…

  8. The Red Effect, Anxiety, and Exam Performance: A Multistudy Examination

    ERIC Educational Resources Information Center

    Smajic, Adnan; Merritt, Stephanie; Banister, Christina; Blinebry, Amanda

    2014-01-01

    Laboratory studies have established a negative relationship between the color red and academic performance. This research examined whether this effect would generalize to classroom performance and whether anxiety and negative affect might mediate the effect. In two studies, students taking classroom exams were randomly assigned an exam color. We

  9. High School Exit Exams and "Mis"measurement

    ERIC Educational Resources Information Center

    Tienken, Christopher H.

    2011-01-01

    Test score validity takes center stage in the debate over the use of high school exit exams. Scant literature addresses the amount of conditional standard error of measurement (CSEM) present in individual student results on high school exit exams. The purpose of this study is to fill a void in the literature and add a national review of the CSEM,

  10. Exit Exams Face Pinch in Common-Core Push

    ERIC Educational Resources Information Center

    Ujifusa, Andrew

    2012-01-01

    With many states crafting assessments based on the common-core standards--and an increasing emphasis on college and career readiness--some are rethinking the kind of tests high school students must pass to graduate, or whether to use such exit exams at all. Twenty-five states, enrolling a total of 34.1 million students, make exit exams a

  11. Standards and Excellence: Evidence from Advanced Placement (AP) Exams

    ERIC Educational Resources Information Center

    Dee, Thomas S.; Jacob, Brian A.

    2009-01-01

    This study assesses the effects of state exit exams on the student utilization of and performance on Advanced Placement (AP) exams. AP programs have become an increasingly popular way of providing fairly standardized and academically rigorous academic experiences that can prepare high school students for the transition to post-secondary schooling.

  12. State High School Exit Exams: Working to Raise Test Scores

    ERIC Educational Resources Information Center

    Center on Education Policy, 2007

    2007-01-01

    The Center on Education Policy (CEP) has been studying state high school exit examinations since 2002. This is the sixth annual report on our comprehensive study of exit exams. The information comes from several sources: our survey of states that have mandatory exit exams, interviews with state officials, media reports, state Web sites, and case

  13. EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS): USER MANUAL AND SYSTEM DOCUMENTATION

    EPA Science Inventory

    The Exposure Analysis Modeling System (EXAMS) was designed for rapid evaluation of the behavior of synthetic organic chemicals in aquatic ecosystems. From the chemistry of a compound and the relevant transport and physical/chemical characteristics of the ecosystem, EXAMS computes...

  14. Relationships between preclinical course grades and standardized exam performance.

    PubMed

    Hu, Yinin; Martindale, James R; LeGallo, Robin D; White, Casey B; McGahren, Eugene D; Schroen, Anneke T

    2016-05-01

    Success in residency matching is largely contingent upon standardized exam scores. Identifying predictors of standardized exam performance could promote primary intervention and lead to design insights for preclinical courses. We hypothesized that clinically relevant courses with an emphasis on higher-order cognitive understanding are most strongly associated with performance on United States Medical Licensing Examination Step exams and National Board of Medical Examiners clinical subject exams. Academic data from students between 2007 and 2012 were collected. Preclinical course scores and standardized exam scores were used for statistical modeling with multiple linear regression. Preclinical courses were categorized as having either a basic science or a clinical knowledge focus. Medical College Admissions Test scores were included as an additional predictive variable. The study sample comprised 795 graduating medical students. Median score on Step 1 was 234 (interquartile range 219-245.5), and 10.2 % (81/795) scored lower than one standard deviation below the national average (205). Pathology course score was the strongest predictor of performance on all clinical subject exams and Step exams, outperforming the Medical College Admissions Test in strength of association. Using Pathology score <75 as a screening metric for Step 1 score <205 results in sensitivity and specificity of 37 and 97 %, respectively, and a likelihood ratio of 11.9. Performance in Pathology, a clinically relevant course with case-based learning, is significantly related to subsequent performance on standardized exams. Multiple linear regression is useful for identifying courses that have potential as risk stratifiers. PMID:26363626

  15. Gender Differences in STEM Related Advanced Placement Exams

    ERIC Educational Resources Information Center

    Morris, Jill B.

    2013-01-01

    Purpose: The purpose of this study was to examine differences between boys and girls in their performance on STEM related AP exams. Specifically, gender differences were examined for the following STEM related AP exams: Calculus AB, Calculus BC, Physics B, Physics C: Electricity and Magnetism, Physics C: Mechanics, Chemistry, and Computer Science

  16. An Expanded Framework for Analyzing General Chemistry Exams

    ERIC Educational Resources Information Center

    Smith, K. Christopher; Nakhleh, Mary B.; Bretz, Stacey Lowery

    2010-01-01

    This paper describes an expanded framework to aid chemical educators in constructing exams for their courses. The framework has three primary levels: definition, algorithmic, and conceptual. These primary levels have often been used in chemical education research to analyze and describe exam questions, but in this study the definition,…

  17. Preparing Students to Take SOA/CAS Exam FM/2

    ERIC Educational Resources Information Center

    Marchand, Richard J.

    2014-01-01

    This paper provides suggestions for preparing students to take the actuarial examination on financial mathematics, SOA/CAS Exam FM/2. It is based on current practices employed at Slippery Rock University, a small public liberal arts university. Detailed descriptions of our Theory of Interest course and subsequent Exam FM/2 prep course are provided

  18. Relationships between Preclinical Course Grades and Standardized Exam Performance

    ERIC Educational Resources Information Center

    Hu, Yinin; Martindale, James R.; LeGallo, Robin D.; White, Casey B.; McGahren, Eugene D.; Schroen, Anneke T.

    2016-01-01

    Success in residency matching is largely contingent upon standardized exam scores. Identifying predictors of standardized exam performance could promote primary intervention and lead to design insights for preclinical courses. We hypothesized that clinically relevant courses with an emphasis on higher-order cognitive understanding are most…

  19. Do Open-Book Exams Impede Long-Term Learning in Introductory Biology Courses?

    ERIC Educational Resources Information Center

    Moore, Randy; Jensen, Philip A.

    2007-01-01

    Students in an introductory biology course who were given open-book exams during the semester earned significantly higher grades on these exams, but significantly lower grades on the closed-book final exam, than students who took in-class, closed-book exams throughout the semester. Exam format was also associated with changes in academic behavior;…

  20. Does requiring graded online homework improve physics exam performance?

    NASA Astrophysics Data System (ADS)

    Chase, Norma

    2012-02-01

    In a first experiment with using Mastering Physics in a first semester calculus-based course, homework and exam performance was tracked periodically during the semester. As expected, the use of novel technology (and its ability to track which students were persistently working at problem exercises) motivated many students to become more involved with work on assigned physics problems. Although there did appear to be a significant correlation between exam averages and homework scores in the upper half of the exam average distribution, individuals spanning the full range of exam averages (down to 45 percent) earned homework scores as high as those who had performed outstandingly well in exams. In this work, we present results and proposed plausible explanations for the apparent anomaly.

  1. Theoretical and experimental validation of treatment planning for narrow MLC defined photon fields

    NASA Astrophysics Data System (ADS)

    Lydon, J. M.

    2005-06-01

    In intensity modulated radiotherapy (IMRT), the use of small fields where electronic equilibrium does not exist is becoming more common and presents difficulties for both the measurement and calculation of dose to such fields. Pinnacle3 (Version 6.2b) allows the user to specify a total minimum open area for each IMRT segment, which can result in sub-segments with widths of only a few millimetres. The dose for 6 MV narrow MLC defined fields between 0.1 and 3 cm in width was investigated using Kodak extended dose range film (EDR2), ionization chamber and MOSFET dosimeters and BEAMnrc Monte Carlo calculations, and these results were used to determine the accuracy of Pinnacle3 dose calculation for narrow MLC segments. The incident fluences calculated by Pinnacle3 and BEAMnrc were also compared. Results show that if a fluence and dose grid resolution of 0.1 cm is used, Pinnacle3 dose agrees with the EDR2 and BEAMnrc to within 5% for field widths between 0.5 and 3.0 cm. However, Pinnacle3 will underestimate the dose by up to 45% for the 0.1 and 0.3 cm wide fields. It is shown that the source size in the Pinnacle3 beam model and both the fluence and dose grid resolutions have a significant effect on the accuracy of dose calculation for field widths of 1.0 cm and less. For single segment fields, Pinnacle3 agrees with EDR2 and BEAMnrc to within 0.1 cm at the field edges and underestimates the penumbra width by up to 0.08 cm. Results for multiple segment fields showed that an MLC transmission of 1.7% and a 0.06 cm inward shift of MLCs prior to beam delivery gave the closest agreement between Pinnacle3 and measurement. The multiple segment fields also revealed a pattern of low dose troughs of up to 7% in the Pinnacle3 dose profiles.

  2. SU-E-T-613: Dosimetric Consequences of Systematic MLC Leaf Positioning Errors

    SciTech Connect

    Kathuria, K; Siebers, J

    2014-06-01

    Purpose: The purpose of this study is to determine the dosimetric consequences of systematic MLC leaf positioning errors for clinical IMRT patient plans so as to establish detection tolerances for quality assurance programs. Materials and Methods: Dosimetric consequences were simulated by extracting mlc delivery instructions from the TPS, altering the file by the specified error, reloading the delivery instructions into the TPS, recomputing dose, and extracting dose-volume metrics for one head-andneck and one prostate patient. Machine error was simulated by offsetting MLC leaves in Pinnacle in a systematic way. Three different algorithms were followed for these systematic offsets, and are as follows: a systematic sequential one-leaf offset (one leaf offset in one segment per beam), a systematic uniform one-leaf offset (same one leaf offset per segment per beam) and a systematic offset of a given number of leaves picked uniformly at random from a given number of segments (5 out of 10 total). Dose to the PTV and normal tissue was simulated. Results: A systematic 5 mm offset of 1 leaf for all delivery segments of all beams resulted in a maximum PTV D98 deviation of 1%. Results showed very low dose error in all reasonably possible machine configurations, rare or otherwise, which could be simulated. Very low error in dose to PTV and OARs was shown in all possible cases of one leaf per beam per segment being offset (<1%), or that of only one leaf per beam being offset (<.2%). The errors resulting from a high number of adjacent leaves (maximum of 5 out of 60 total leaf-pairs) being simultaneously offset in many (5) of the control points (total 10–18 in all beams) per beam, in both the PTV and the OARs analyzed, were similarly low (<2–3%). Conclusions: The above results show that patient shifts and anatomical changes are the main source of errors in dose delivered, not machine delivery. These two sources of error are “visually complementary” and uncorrelated (albeit not additive in the final error) and one can easily incorporate error resulting from machine delivery in an error model based purely on tumor motion.

  3. SU-E-T-633: Dose Differences in Lung Cancer SBRT: The Influences of MLC Width

    SciTech Connect

    Chen, J; Yin, Y

    2014-06-15

    Purpose: The aim is to compare the plan dose distribution of lung SBRT with MLCs in different width. Methods: Cases with phase INSCLC were enrolled. 9 cases were undergone 4D-CT scanning in the supine position with both arms raised. 3D-CT images without IV contrast were afterwards acquired with 3mm thickness and used for dose calculations. ITV was generated by using the inspiration and expiration images. The ITV can be expanded by geometric set-up uncertainty (5 mm) to generate the PTV. All chest normal tissues including chest wall were contoured by doctors. A total dose of 55 Gy will be given in 5 fractions within 10–14 days with an inter fraction interval of 2–3 days. Guided by the RTOG trial 3502 protocol, 11–13 non-coplanar fields with 6MV photon were arranged. Three types of MLCs with width of 3mm, 5mm and 10mm at isocenter position, were used separately to generate a CRT plan for each case. Monte Carlo algorithm was applied to dose calculation. All plans were adjusted as possible to meet the dose constraints. Dose-volume parameters from plans as followed were compared and analysized: PTV V55Gy, COMPTV D70% (70% of normalization dose), volume A (body minus PTV), and R100% and R50% (the ratio of x% of prescription dose isoline volume to PTV volume). Results: MLCs, 3mm and 5mm wide, played the identical roles on dosimetry of the plans, excluding the parameter volume A (p<0.05). On the contrary, MLC with width of 10mm was significantly inferior to the other two types on most parameters (p<0.05). For R50%, all types contributed equally (p>0.05). Conclusion: For lung cancer SBRT, MLC width had influence to dosimetry, especially in irradiation area. Small size MLC, e.g. 3mm and 5mm, are helpful to generate a high quality treatment plan, which could meet the strict criteria for targets and OAR.

  4. SU-E-T-425: Spherical Dose Distributions for Radiosurgery Using a Standardized MLC Plan

    SciTech Connect

    Popple, R; Brezovich, I; Wu, X; Fiveash, J

    2014-06-01

    Purpose: To investigate a standardized MLC treatment plan to generate small spherical dose distributions. Methods: The static virtual cone plan comprised six table positions with clockwise and counterclockwise arcs having collimator angles 45 and 135 degrees, respectively, at each position. The central two leaves of a 2.5 mm leaf width MLC were set to a constant gap. Control points were weighted proportional to the sine of the gantry angle. Plans were created for the 10 MV flattening-filter-free beam of a TrueBeam STx (Varian Medical Systems) with gaps of 1, 1.5, 2, and 3 mm and were delivered to a phantom containing radiochromic film. Dose was calculated using the Eclipse AAA (Varian Medical Systems). A dynamic plan in which the table and gantry moved simultaneously with 1.5 mm gap was also created and delivered using the TrueBeam developer mode. Results: The full-width-half-max (FWHM) varied with leaf gap, ranging from 5.2 to 6.2 mm. Calculated FWHM was smaller than measured by 0.7 mm for the 1 mm gap and ≤ 0.4 mm for the larger gaps. The measured-to-calculated dose ratio was 0.93, 0.96, 1.01, and 0.99 for 1 mm, 1.5 mm, 2 mm, and 3 mm gaps, respectively. The dynamic results were the same as the static. The position deviations between the phantom target position and the center of the dose distribution were < 0.4 mm. Conclusion: The virtual cone can deliver spherical dose distributions suitable for radio surgery of small targets such as the trigeminal nerve. The Eclipse AAA accurately calculates the expected dose, particularly for leaf gap ≥ 1.5 mm. The measured dose distribution is slightly larger than the calculation, which is likely due to systematic leaf position error, isocenter variation due to gantry sag and table eccentricity, and inaccuracy in MLC leaf end modeling.

  5. The Impact of Statewide Exit Exams: A Descriptive Case Study of Three German States with Differing Low Stakes Exam Regimes

    ERIC Educational Resources Information Center

    van Ackeren, Isabell; Block, Rainer; Klein, E. Dominique; Kuhn, Svenja M.

    2012-01-01

    In this article we present results from a study investigating the impact of three state exit exam systems on teaching and learning in college-preparatory schools. The study compares one state with a traditionally more centralized exam regime, one state that is more de-centralized and one state that has recently switched to more centralized…

  6. Comparability of Semester and Exit Exam Grades: Long-Term Effect of the Implementation of State-Wide Exit Exams

    ERIC Educational Resources Information Center

    Maag Merki, Katharina; Holmeier, Monika

    2015-01-01

    A goal in many countries is to institute state-wide exams to base student assessment more firmly on norms for all classes. This raises the question as to the extent to which greater standardization of grading practice can be reached by implementing state-wide exit exams. Since there is a lack of longitudinal studies, we analyzed the effect of the…

  7. Comparability of Semester and Exit Exam Grades: Long-Term Effect of the Implementation of State-Wide Exit Exams

    ERIC Educational Resources Information Center

    Maag Merki, Katharina; Holmeier, Monika

    2015-01-01

    A goal in many countries is to institute state-wide exams to base student assessment more firmly on norms for all classes. This raises the question as to the extent to which greater standardization of grading practice can be reached by implementing state-wide exit exams. Since there is a lack of longitudinal studies, we analyzed the effect of the

  8. SU-E-T-122: Dosimetric Comparison Between Cone, HDMLC and MicroMLC for the Treatment of Trigeminal Neuralgia

    SciTech Connect

    Vacca, N; Caussa, L; Filipuzzi, M; Garrigo, E; Venencia, C

    2014-06-01

    Purpose: The purpose of this work was to evaluate the dosimetric characteristics of three collimation systems, 5mm circular cone (Brainlab) and square fields of 5mm with HDMLC (Varian) and microMLC Moduleaf, Siemens) for trigeminal neuralgia treatment. Methods: A TPS Iplan v4.5 BrainLAB was used to do treatment plans for each collimations system in a square solid water phantom with isocenter at 5cm depth. Single field and treatment plan including 11 arcs with fix field and 100° gantry range was made for each collimation systems. EBT3 films were positioned at isocenter in a coronal plane to measured dose distribution for all geometries. Films were digitized with a Vidar DosimetryPro Red scanner with a resolution of 89dpi and RIT113v6.1 software was used for analysis. Penumbra region (80%–20%), FWHM and dose percentage at 5mm and 10mm from CAX were determined. All profiles were normalized at CAX. Results: For single beam the penumbra (FWHM) was 1.5mm (5.3mm) for the cone, 1.9mm (5.5mm) for HDMLC and 1.8mm (5.4mm) for the microMLC. Dose percentage at 5mm was 6.9% for cone, 12.5% for HDMLC and 8.7% for the microMLC. For treatment plan the penumbra (FWHM) was 2.58mm (5.47mm) for the cone, 2.8mm (5.84mm) for HDMLC and 2.58mm (6.09mm) for the microMLC. Dose perecentage at 5mm was 13.1% for cone, 16.1% for HDMLC, 15.2% for the microMLC. Conclusion: The cone has a dose falloff larger than the microMLC and HDMLC, by its reduced penumbra, this translates into better protection of surrounding healthy tissue, however, the microMLC and HDMLC have similar accuracy to cone.

  9. Evaluation of dosimetric effect caused by slowing with multi-leaf collimator (MLC) leaves for volumetric modulated arc therapy (VMAT)

    PubMed Central

    Wang, Iris Z.; Kumaraswamy, Lalith K.; Podgorsak, Matthew B.

    2016-01-01

    Background This study is to report 1) the sensitivity of intensity modulated radiation therapy (IMRT) QA method for clinical volumetric modulated arc therapy (VMAT) plans with multi-leaf collimator (MLC) leaf errors that will not trigger MLC interlock during beam delivery; 2) the effect of non-beam-hold MLC leaf errors on the quality of VMAT plan dose delivery. Materials and methods. Eleven VMAT plans were selected and modified using an in-house developed software. For each control point of a VMAT arc, MLC leaves with the highest speed (1.87-1.95 cm/s) were set to move at the maximal allowable speed (2.3 cm/s), which resulted in a leaf position difference of less than 2 mm. The modified plans were considered as ‘standard’ plans, and the original plans were treated as the ‘slowing MLC’ plans for simulating ‘standard’ plans with leaves moving at relatively lower speed. The measurement of each ‘slowing MLC’ plan using MapCHECK®2 was compared with calculated planar dose of the ‘standard’ plan with respect to absolute dose Van Dyk distance-to-agreement (DTA) comparisons using 3%/3 mm and 2%/2 mm criteria. Results All ‘slowing MLC’ plans passed the 90% pass rate threshold using 3%/3 mm criteria while one brain and three anal VMAT cases were below 90% with 2%/2 mm criteria. For ten out of eleven cases, DVH comparisons between ‘standard’ and ‘slowing MLC’ plans demonstrated minimal dosimetric changes in targets and organs-at-risk. Conclusions For highly modulated VMAT plans, pass rate threshold (90%) using 3%/3mm criteria is not sensitive in detecting MLC leaf errors that will not trigger the MLC leaf interlock. However, the consequential effects of non-beam hold MLC errors on target and OAR doses are negligible, which supports the reliability of current patient-specific IMRT quality assurance (QA) method for VMAT plans. PMID:27069458

  10. High-Dose Spatially Fractionated GRID Radiation Therapy (SFGRT): A Comparison of Treatment Outcomes With Cerrobend vs. MLC SFGRT

    SciTech Connect

    Neuner, Geoffrey; Mohiuddin, Majid M.; Vander Walde, Noam; Goloubeva, Olga; Ha, Jonathan; Yu, Cedric X.; Regine, William F.

    2012-04-01

    Purpose: Spatially fractionated GRID radiotherapy (SFGRT) using a customized Cerrobend block has been used to improve response rates in patients with bulky tumors. The clinical efficacy of our own multileaf collimator (MLC) technique is unknown. We undertook a retrospective analysis to compare clinical response rates attained using these two techniques. Methods and Materials: Seventy-nine patients with bulky tumors (median diameter, 7.6 cm; range, 4-30 cm) treated with SFGRT were reviewed. Between 2003 and late 2005, the Cerrobend block technique (n = 39) was used. Between late 2005 and 2008, SFGRT was delivered using MLC-shaped fields (n = 40). Dose was prescribed to dmax (depth of maximum dose) and was typically 15 Gy. Eighty percent of patients in both groups received external beam radiotherapy in addition to SFGRT. The two-sided Fisher-Freeman-Halton test was used to compare pain and mass effect response rates between the two groups. Results: Sixty-one patients (77%) were treated for palliative intent and 18 (23%) for curative intent. The majority of patients had either lung or head-and-neck primaries in both groups; the most frequent site of SFGRT application was the neck. The majority of patients complained of either pain (65%) or mass effect (58%) at intake. Overall response rates for pain and mass response were no different between the Cerrobend and MLC groups: pain, 75% and 74%, respectively (p = 0.50), and mass effect, 67% and 73%, respectively (p = 0.85). The majority of toxicities were Grade 1 or 2, and only 3 patients had late Grade 3-4 toxicities. Conclusions: MLC-based and Cerrobend-based SFGRT have comparable and encouraging response rates when used either in the palliative or curative setting. MLC-based SGFRT should allow clinics to more easily adopt this novel treatment approach for the treatment of bulky tumors.

  11. Beamlet based direct aperture optimization for MERT using a photon MLC

    SciTech Connect

    Henzen, D. Manser, P.; Frei, D.; Volken, W.; Born, E. J.; Joosten, A.; Lössl, K.; Aebersold, D. M.; Chatelain, C.; Fix, M. K.; Neuenschwander, H.; Stampanoni, M. F. M.

    2014-12-15

    Purpose: A beamlet based direct aperture optimization (DAO) for modulated electron radiotherapy (MERT) using photon multileaf collimator (pMLC) shaped electron fields is developed and investigated. Methods: The Swiss Monte Carlo Plan (SMCP) allows the calculation of dose distributions for pMLC shaped electron beams. SMCP is interfaced with the Eclipse TPS (Varian Medical Systems, Palo Alto, CA) which can thus be included into the inverse treatment planning process for MERT. This process starts with the import of a CT-scan into Eclipse, the contouring of the target and the organs at risk (OARs), and the choice of the initial electron beam directions. For each electron beam, the number of apertures, their energy, and initial shape are defined. Furthermore, the DAO requires dose–volume constraints for the structures contoured. In order to carry out the DAO efficiently, the initial electron beams are divided into a grid of beamlets. For each of those, the dose distribution is precalculated using a modified electron beam model, resulting in a dose list for each beamlet and energy. Then the DAO is carried out, leading to a set of optimal apertures and corresponding weights. These optimal apertures are now converted into pMLC shaped segments and the dose calculation for each segment is performed. For these dose distributions, a weight optimization process is launched in order to minimize the differences between the dose distribution using the optimal apertures and the pMLC segments. Finally, a deliverable dose distribution for the MERT plan is obtained and loaded back into Eclipse for evaluation. For an idealized water phantom geometry, a MERT treatment plan is created and compared to the plan obtained using a previously developed forward planning strategy. Further, MERT treatment plans for three clinical situations (breast, chest wall, and parotid metastasis of a squamous cell skin carcinoma) are created using the developed inverse planning strategy. The MERT plans are compared to clinical standard treatment plans using photon beams and the differences between the optimal and the deliverable dose distributions are determined. Results: For the idealized water phantom geometry, the inversely optimized MERT plan is able to obtain the same PTV coverage, but with an improved OAR sparing compared to the forwardly optimized plan. Regarding the right-sided breast case, the MERT plan is able to reduce the lung volume receiving more than 30% of the prescribed dose and the mean lung dose compared to the standard plan. However, the standard plan leads to a better homogeneity within the CTV. The results for the left-sided thorax wall are similar but also the dose to the heart is reduced comparing MERT to the standard treatment plan. For the parotid case, MERT leads to lower doses for almost all OARs but to a less homogeneous dose distribution for the PTV when compared to a standard plan. For all cases, the weight optimization successfully minimized the differences between the optimal and the deliverable dose distribution. Conclusions: A beamlet based DAO using multiple beam angles is implemented and successfully tested for an idealized water phantom geometry and clinical situations.

  12. Dosimetric evaluation of photon dose calculation under jaw and MLC shielding

    SciTech Connect

    Fogliata, A.; Clivio, A.; Vanetti, E.; Nicolini, G.; Belosi, M. F.; Cozzi, L.

    2013-10-15

    Purpose: The accuracy of photon dose calculation algorithms in out-of-field regions is often neglected, despite its importance for organs at risk and peripheral dose evaluation. The present work has assessed this for the anisotropic analytical algorithm (AAA) and the Acuros-XB algorithms implemented in the Eclipse treatment planning system. Specifically, the regions shielded by the jaw, or the MLC, or both MLC and jaw for flattened and unflattened beams have been studied.Methods: The accuracy in out-of-field dose under different conditions was studied for two different algorithms. Measured depth doses out of the field, for different field sizes and various distances from the beam edge were compared with the corresponding AAA and Acuros-XB calculations in water. Four volumetric modulated arc therapy plans (in the RapidArc form) were optimized in a water equivalent phantom, PTW Octavius, to obtain a region always shielded by the MLC (or MLC and jaw) during the delivery. Doses to different points located in the shielded region and in a target-like structure were measured with an ion chamber, and results were compared with the AAA and Acuros-XB calculations. Photon beams of 6 and 10 MV, flattened and unflattened were used for the tests.Results: Good agreement between calculated and measured depth doses was found using both algorithms for all points measured at depth greater than 3 cm. The mean dose differences (±1SD) were −8%± 16%, −3%± 15%, −16%± 18%, and −9%± 16% for measurements vs AAA calculations and −10%± 14%, −5%± 12%, −19%± 17%, and −13%± 14% for Acuros-XB, for 6X, 6 flattening-filter free (FFF), 10X, and 10FFF beams, respectively. The same figures for dose differences relative to the open beam central axis dose were: −0.1%± 0.3%, 0.0%± 0.4%, −0.3%± 0.3%, and −0.1%± 0.3% for AAA and −0.2%± 0.4%, −0.1%± 0.4%, −0.5%± 0.5%, and −0.3%± 0.4% for Acuros-XB. Buildup dose was overestimated with AAA, while Acuros-XB gave results more consistent with measurements. From RapidArc plan analysis the average difference between calculation and measurement in the shielded region was −0.3%± 0.4% and −2.5%± 1.2% for AAA and Acuros-XB, respectively, relative to the mean target dose value (1.6%± 2.3%, −12.7%± 4.0% if relative to each local value). These values were compared with the corresponding differences in the target structure: −0.7%± 2.3% for AAA, and −0.5%± 2.3% for Acuros-XB.Conclusions: The two algorithms analyzed showed encouraging results in predicting out-of-field region dose for clinical use.

  13. Verification of MLC based real-time tumor tracking using an electronic portal imaging device

    PubMed Central

    Han-Oh, Sarah; Yi, Byong Yong; Lerma, Fritz; Berman, Barry L.; Gui, Minzhi; Yu, Cedric

    2010-01-01

    Purpose: The authors have developed a novel technique using an electronic portal imaging device (EPID) to verify the geometrical accuracy of delivery of dose-rate-regulated tracking (DRRT). This technique, called verification of real-time tracking with EPID (VORTE), can potentially be used for both on-line and off-line quality assurance (QA) of MLC-based dynamic tumor tracking. Methods: The shape and position of target as a function of time, which is assumed to be known, is projected onto the EPID plane. This projected sequence of apertures as a function of time (target motion) is then used as the reference. The accuracy of dynamic MLC tracking can then be assessed by how well the delivered beam follows this projected target motion without the use of a physical moving phantom. The beam apertures controlled by DRRT (aperture motion) is detected by the EPID as a function of time. The aperture motion is compared to the target motion to evaluate tracking error introduced by DRRT. The accuracy of VORTE was measured using film measurements of ten static fields. The VORTE for dynamic tumor tracking was tested with several target motions, including (1) rigid-body two-dimensional (2-D) cyclic motion in the superior-inferior direction with various period and amplitude; (2) the above 2-D cyclic motion plus cyclic deformation; and (3) 2-D cyclic motion with both deformation and rotation. For each target motion, the controlled aperture motion resulting from DRRT was acquired at ∼8 Hz using EPID in the continuous-acquisition mode. Leaf positions in all captured frames were measured from the EPID and compared to their expected positions. The passing rate of 2 mm criteria for all leaves from all frames was calculated for each of the four patterns of tumor motion. Additionally, the root-mean-square (RMS) deviations of the centroid of the apertures between the designed and delivered beams were calculated for all three cases. Results: The accuracy of MLC-leaf position determination by VORTE is 0.5 mm (1 standard deviation) by comparison to film measurements. With DRRT, the passing rates using the 2 mm criteria for all acquired frames are 100% for the 2-D displacement, 99% for the 2-D displacement with deformation, and 88% for the 2-D displacement combined with both deformation and rotation. The RMS deviations are 0.6 mm for the 2-D displacement, 1.0 mm for the 2-D displacement with deformation, and 1.1 mm for the 2-D displacement combined with both deformation and rotation. Conclusions: The VORTE can measure the accuracy of MLC-based tumor tracking without the necessity of employing a moving phantom. Moreover, it can be used for complex target motion (i.e., 2-D displacement combined with deformation and rotation) that is difficult to create with physical moving phantoms. Therefore, the VORTE and the novel QA process illustrated by this study have a great potential for verifying real-time tumor tracking. PMID:20632553

  14. Evaluation of MLC leaf positioning accuracy for static and dynamic IMRT treatments using DAVID in vivo dosimetric system.

    PubMed

    Karagoz, Gulay; Zorlu, Faruk; Yeginer, Mete; Yildiz, Demet; Ozyigit, Gokhan

    2016-01-01

    Accuracy and precision of leaf positioning in multileaf collimators (MLCs) are significant factors for the accuracy of IMRT treatments. This study aimed to inves-tigate the accuracy and repeatability of the MLC leaf positioning via the DAVID invivo dosimetric system for dynamic and static MLC systems. The DAVID system was designed as multiwire transmission ionization chamber which is placed in accessory holder of linear accelerators. Each wire of DAVID system corresponds to a MLC leaf-pair to verify the leaf positioning accuracy during IMRT treatment and QA. In this study, verifications of IMRT plans of five head and neck (H&N) and five prostate patients treated in a Varian DHX linear accelerator with 80-leaf MLC were performed using DAVID system. Before DAVID-based dosimetry, Electronics Portal Imaging Device (EPID) and PTW 2D ARRAY dosimetry system were used for 2D verification of each plan. The measurements taken by DAVID system in the first day of the treatments were used as reference for the following measurements taken over the next four weeks. The deviations in leaf positioning were evaluated by "Total Deviation (TD)" parameter calculated by DAVID software. The delivered IMRT plans were originally prepared using dynamic MLC method. The same plans were subsequently calculated based on static MLC method with three different intensity levels of five (IL5), 10 (IL10) and 20 (IL20) in order to compare the performances of MLC leaf positioning repeatability for dynamic and static IMRT plans. The leaf positioning accuracy is also evaluated by analyzing DynaLog files based on error histograms and root mean square (RMS) errors of leaf pairs' positions. Moreover, a correlation analysis between simultaneously taken DAVID and EPID measurements and DynaLog file recordings was subsequently performed. In the analysis of DAVID outputs, the overall deviations of dynamic MLC-based IMRT calculated from the deviations of the four weeks were found as 0.55% ± 0.57% and 1.48% ± 0.57% for prostate and H&N patients, respectively. The prostate IMRT plans based on static MLC method had the overall deviations of 1.23% ± 0.69%, 3.07% ± 1.07%, and 3.13% ± 1.29% for intensity levels of IL5, IL10, and IL20, respectively. Moreover, the overall deviations for H&N patients were found as 1.87% ± 0.86%, 3.11% ± 1.24%, and 2.78% ± 1.31% for the static MLC-based IMRT plans with intensity levels of IL5, IL10 and IL20, respectively. Similar with the DAVID results, the error rates in DynaLog files showed upward movement comparing the dynamic IMRT with static IMRT with high intensity levels. In respect to positioning errors higher than 0.005 cm, static prostate IMRT plans with intensity levels of IL10 and IL20 had 1.5 and 2.6 times higher error ratios than dynamic prostate IMRT plans, respectively, while these values stepped up to 8.4 and 12.0 for H&N cases. On the other hand, according to the leaf pair readings, reconstructed dose values from DynaLog files had significant correlation (r = 0.80) with DAVID and EPID readings while a stronger relationship (r = 0.98) was found between the two dosimetric systems. The correlation coefficients for deviations from reference plan readings were found in the interval of -0.21-0.16 for all three systems. The dynamic MLC method showed higher performance in repeatability of leaf positioning than static MLC methods with higher intensity levels even though the deviations in the MLC leaf positioning were found to be under the acceptance threshold for all MLC methods. The high intensity levels increased the position-ing deviations along with the delivery complexity of the static MLC-based IMRT plans. Moreover, DAVID and EPID readings and DynaLog recordings showed mutually strong correlation, while no significant relationship was found between deviations from reference values. PMID:27074451

  15. Mlc Is a Transcriptional Activator with a Key Role in Integrating Cyclic AMP Receptor Protein and Integration Host Factor Regulation of Leukotoxin RNA Synthesis in Aggregatibacter actinomycetemcomitans

    PubMed Central

    Childress, Catherine; Feuerbacher, Leigh A.; Phillips, Linda; Burgum, Alex

    2013-01-01

    Aggregatibacter actinomycetemcomitans, a periodontal pathogen, synthesizes leukotoxin (LtxA), a protein that helps the bacterium evade the host immune response. Transcription of the ltxA operon is induced during anaerobic growth. The cyclic AMP (cAMP) receptor protein (CRP) indirectly increases ltxA expression, but the intermediary regulator is unknown. Integration host factor (IHF) binds to and represses the leukotoxin promoter, but neither CRP nor IHF is responsible for the anaerobic induction of ltxA RNA synthesis. Thus, we have undertaken studies to identify other regulators of leukotoxin transcription and to demonstrate how these proteins work together to modulate leukotoxin synthesis. First, analyses of ltxA RNA expression from defined leukotoxin promoter mutations in the chromosome identify positions ?69 to ?35 as the key control region and indicate that an activator protein modulates leukotoxin transcription. We show that Mlc, which is a repressor in Escherichia coli, functions as a direct transcriptional activator in A. actinomycetemcomitans; an mlc deletion mutant reduces leukotoxin RNA synthesis, and recombinant Mlc protein binds specifically at the ?68 to ?40 region of the leukotoxin promoter. Furthermore, we show that CRP activates ltxA expression indirectly by increasing the levels of Mlc. Analyses of ?mlc, ?ihf, and ?ihf ?mlc strains demonstrate that Mlc can increase RNA polymerase (RNAP) activity directly and that IHF represses ltxA RNA synthesis mainly by blocking Mlc binding. Finally, a ?ihf ?mlc mutant still induces ltxA during anaerobic growth, indicating that there are additional factors involved in leukotoxin transcriptional regulation. A model for the coordinated regulation of leukotoxin transcription is presented. PMID:23475968

  16. Retrospective IMRT Dose Reconstruction Based on Cone-Beam CT and MLC Log-File

    SciTech Connect

    Lee, Louis; Le, Quynh-Thu; Xing Lei

    2008-02-01

    Purpose: Head-and-neck (HN) cone-beam computed tomography (CBCT) can be exploited to probe the IMRT dose delivered to a patient taking into account the interfraction anatomic variation and any potential inaccuracy in the IMRT delivery. The aim of this work is to reconstruct the intensity-modulated radiation therapy dose delivered to an HN patient using the CBCT and multileaf collimator (MLC) log-files. Methods and Materials: A cylindrical CT phantom was used for calibrating the electron density and validating the procedures of the dose reconstruction. Five HN patients were chosen, and for each patient, CBCTs were performed on three separate fractions spaced every 2 weeks starting from the first fraction. The respective MLC log-files were retrieved and converted into fluence maps. The dose was then reconstructed on the corresponding CBCT with the regenerated fluence maps. The reconstructed dose distribution, dosimetric endpoints, and DVHs were compared with that of the treatment plan. Results: Phantom study showed that HN CBCT can be directly used for dose reconstruction. For most treatment sessions, the CBCT-based dose reconstructions yielded DVHs of the targets close (within 3%) to that of the original treatment plans. However, dosimetric changes (within 10%) due to anatomic variations caused by setup inaccuracy, organ deformation, tumour shrinkage, or weight loss (or a combination of these) were observed for the critical organs. Conclusions: The methodology we established affords an objective dosimetric basis for the clinical decision on whether a replanning is necessary during the course of treatment and provides a valuable platform for adaptive therapy in future.

  17. Performance analysis of exam gloves used for aseptic rodent surgery.

    PubMed

    LeMoine, Dana M; Bergdall, Valerie K; Freed, Carrie

    2015-05-01

    Aseptic technique includes the use of sterile surgical gloves for survival surgeries in rodents to minimize the incidence of infections. Exam gloves are much less expensive than are surgical gloves and may represent a cost-effective, readily available option for use in rodent surgery. This study examined the effectiveness of surface disinfection of exam gloves with 70% isopropyl alcohol or a solution of hydrogen peroxide and peracetic acid (HP-PA) in reducing bacterial contamination. Performance levels for asepsis were met when gloves were negative for bacterial contamination after surface disinfection and sham 'exertion' activity. According to these criteria, 94% of HP-PA-disinfected gloves passed, compared with 47% of alcohol-disinfected gloves. In addition, the effect of autoclaving on the integrity of exam gloves was examined, given that autoclaving is another readily available option for aseptic preparation. Performance criteria for glove integrity after autoclaving consisted of: the ability to don the gloves followed by successful simulation of wound closure and completion of stretch tests without tearing or observable defects. Using this criteria, 98% of autoclaved nitrile exam gloves and 76% of autoclaved latex exam gloves met performance expectations compared with the performance of standard surgical gloves (88% nitrile, 100% latex). The results of this study support the use of HP-PA-disinfected latex and nitrile exam gloves or autoclaved nitrile exam gloves as viable cost-effective alternatives to sterile surgical gloves for rodent surgeries. PMID:26045458

  18. Performance Analysis of Exam Gloves Used for Aseptic Rodent Surgery

    PubMed Central

    LeMoine, Dana M; Bergdall, Valerie K; Freed, Carrie

    2015-01-01

    Aseptic technique includes the use of sterile surgical gloves for survival surgeries in rodents to minimize the incidence of infections. Exam gloves are much less expensive than are surgical gloves and may represent a cost-effective, readily available option for use in rodent surgery. This study examined the effectiveness of surface disinfection of exam gloves with 70% isopropyl alcohol or a solution of hydrogen peroxide and peracetic acid (HP–PA) in reducing bacterial contamination. Performance levels for asepsis were met when gloves were negative for bacterial contamination after surface disinfection and sham ‘exertion’ activity. According to these criteria, 94% of HP–PA-disinfected gloves passed, compared with 47% of alcohol-disinfected gloves. In addition, the effect of autoclaving on the integrity of exam gloves was examined, given that autoclaving is another readily available option for aseptic preparation. Performance criteria for glove integrity after autoclaving consisted of: the ability to don the gloves followed by successful simulation of wound closure and completion of stretch tests without tearing or observable defects. Using this criteria, 98% of autoclaved nitrile exam gloves and 76% of autoclaved latex exam gloves met performance expectations compared with the performance of standard surgical gloves (88% nitrile, 100% latex). The results of this study support the use of HP–PA-disinfected latex and nitrile exam gloves or autoclaved nitrile exam gloves as viable cost-effective alternatives to sterile surgical gloves for rodent surgeries. PMID:26045458

  19. FLEX: A Modular Software Architecture for Flight License Exam

    NASA Astrophysics Data System (ADS)

    Arsan, Taner; Saka, Hamit Emre; Sahin, Ceyhun

    This paper is about the design and implementation of an examination system based on World Wide Web. It is called FLEX-Flight License Exam Software. We designed and implemented flexible and modular software architecture. The implemented system has basic specifications such as appending questions in system, building exams with these appended questions and making students to take these exams. There are three different types of users with different authorizations. These are system administrator, operators and students. System administrator operates and maintains the system, and also audits the system integrity. The system administrator can not be able to change the result of exams and can not take an exam. Operator module includes instructors. Operators have some privileges such as preparing exams, entering questions, changing the existing questions and etc. Students can log on the system and can be accessed to exams by a certain URL. The other characteristic of our system is that operators and system administrator are not able to delete questions due to the security problems. Exam questions can be inserted on their topics and lectures in the database. Thus; operators and system administrator can easily choose questions. When all these are taken into consideration, FLEX software provides opportunities to many students to take exams at the same time in safe, reliable and user friendly conditions. It is also reliable examination system for the authorized aviation administration companies. Web development platform - LAMP; Linux, Apache web server, MySQL, Object-oriented scripting Language - PHP are used for developing the system and page structures are developed by Content Management System - CMS.

  20. Computer-aided training exam creation and personnel records management

    SciTech Connect

    Lawton, R.K.; Louche, K.A.

    1985-11-01

    A problem has existed in nuclear power plant training departments about how to choose questions for examinations without instructor bias, how to permanently store this exam so that it can be reconstructed, how to statistically analyze class, instructor, and student performance, and how to keep accurate, easily accessible records of all training. The design of the software package discussed in the paper is such that a complete record of classes, quizzes, exams, instructors, and analysis is available for each trainee. The need for classes is automatically available from the computer with randomly created exams available on request.

  1. Verification of dosimetric accuracy on the TrueBeam STx: Rounded leaf effect of the high definition MLC

    SciTech Connect

    Kielar, Kayla N.; Mok, Ed; Hsu, Annie; Wang Lei; Luxton, Gary

    2012-10-15

    Purpose: The dosimetric leaf gap (DLG) in the Varian Eclipse treatment planning system is determined during commissioning and is used to model the effect of the rounded leaf-end of the multileaf collimator (MLC). This parameter attempts to model the physical difference between the radiation and light field and account for inherent leakage between leaf tips. With the increased use of single fraction high dose treatments requiring larger monitor units comes an enhanced concern in the accuracy of leakage calculations, as it accounts for much of the patient dose. This study serves to verify the dosimetric accuracy of the algorithm used to model the rounded leaf effect for the TrueBeam STx, and describes a methodology for determining best-practice parameter values, given the novel capabilities of the linear accelerator such as flattening filter free (FFF) treatments and a high definition MLC (HDMLC). Methods: During commissioning, the nominal MLC position was verified and the DLG parameter was determined using MLC-defined field sizes and moving gap tests, as is common in clinical testing. Treatment plans were created, and the DLG was optimized to achieve less than 1% difference between measured and calculated dose. The DLG value found was tested on treatment plans for all energies (6 MV, 10 MV, 15 MV, 6 MV FFF, 10 MV FFF) and modalities (3D conventional, IMRT, conformal arc, VMAT) available on the TrueBeam STx. Results: The DLG parameter found during the initial MLC testing did not match the leaf gap modeling parameter that provided the most accurate dose delivery in clinical treatment plans. Using the physical leaf gap size as the DLG for the HDMLC can lead to 5% differences in measured and calculated doses. Conclusions: Separate optimization of the DLG parameter using end-to-end tests must be performed to ensure dosimetric accuracy in the modeling of the rounded leaf ends for the Eclipse treatment planning system. The difference in leaf gap modeling versus physical leaf gap dimensions is more pronounced in the more recent versions of Eclipse for both the HDMLC and the Millennium MLC. Once properly commissioned and tested using a methodology based on treatment plan verification, Eclipse is able to accurately model radiation dose delivered for SBRT treatments using the TrueBeam STx.

  2. Do Weekly Quizzes Improve Student Performance on General Biology Exams?

    ERIC Educational Resources Information Center

    Haberyan, Kurt A.

    2003-01-01

    Evaluates the impact of quizzes on student performance among non-biology major freshmen. Administers weekly quizzes and compares with the control group who experience no quizzes. Reports no significant improvement in exam scores. (YDS)

  3. Exam Question Exchange: A Popular Approach to Reaction Kinetics.

    ERIC Educational Resources Information Center

    Collins, Michael P. S.; Alexander, John J., Ed.

    1979-01-01

    Presents an undergraduate physical chemistry question and its acceptable solution. This question, presented to share exam questions with other teachers, shows the analogy between molecular kinetics and population dynamics. (HM)

  4. Keep Your Vision Healthy: Learn About Comprehensive Dilated Eye Exams

    MedlinePlus

    ... Keep Your Vision Healthy Learn About Comprehensive Dilated Eye Exams People of all ages should have their ... only way to know for sure that your eyes are healthy is to get a comprehensive dilated ...

  5. Are study strategies related to medical licensing exam performance?

    PubMed Central

    West, Courtney; Kurz, Terri; Smith, Sherry; Graham, Lori

    2014-01-01

    Objectives: To examine the relationship between study strategies and performance on a high stakes medical licensing exam entitled the United States Medical Licensing Examination Step 1. Methods: The action research project included seventy nine student participants at the Texas A&M Health Science Center College of Medicine during their pre-clinical education. Data collection included pre-matriculation and matriculation academic performance data, standardized exam data, and the Learning and Study Strategies Instrument. Multiple regression analyses were conducted. For both models, the dependent variable was the Step 1 score, and the independent variables included Medical College Admission Test, Undergraduate Grade Point Average, Year 1 Average, Year 2 Average, Customized National Board of Medical Examiners Average, Comprehensive Basic Science Exam score, and Learning and Study Strategy Instrument sub-scores. Model 2 added Comprehensive Basic Science Self-Assessment average. Results: Concentration (Model 1 - β = .264; Model 2 - β = .254) was the only study strategy correlated with Step 1 performance. The other statistically significant predictors were Customized National Board of Medical Examiners Average (β = .315) and Year 2 Average (β = .280) in Model 1 and Comprehensive Basic Science Self-Assessment Average (β = .338) in Model 2. Conclusions: There does appear to be a relationship between the study strategy concentration and Step 1 licensing exam performance. Teaching students to practice and utilize certain techniques to improve concentration skills when preparing for and taking exams may help improve licensing exam scores. PMID:25362627

  6. Indian Reserved Water Rights.

    ERIC Educational Resources Information Center

    Bond, Frank M.

    1986-01-01

    Traces the distribution, ownership, and water usage associated with lands in the Colville Reservation in Washington State. Cites specific cases which addressed the reserved water rights doctrine. Assesses the impact of court decisions on insuring water rights for Indians living on the Colville Reservation. (ML)

  7. SU-C-BRB-04: Characteristics and Performance Evaluation of the First Commercial MLC for a Robotic Delivery System

    SciTech Connect

    Fuerweger, C; Prins, P; Coskan, H; Heijmen, B

    2015-06-15

    Purpose: To assess characteristics and performance of the “Incise™” MLC (41 leaf pairs, 2.5mm width, FFF linac) mounted on the robotic SRS/SBRT platform “CyberKnife M6™” in a pre-clinical 5 months (11/2014–03/2015) test period. Methods: Beam properties were measured with unshielded diodes and EBT3 film. The CyberKnife workspace for MLC was analyzed by transforming robot node coordinates (cranial / body paths) into Euler geometry. Bayouth tests for leaf / bank position accuracy were performed in standard (A/P) and clinically relevant non-standard positions, before and after exercising the MLC for 10+ minutes. Total system and delivery accuracy were assessed in End-to-End tests and dosimetric verification of exemplary plans. Stability over time was evaluated in Picket-Fence-and adapted Winston-Lutz-tests (AQA) for different collimator angles. Results: Penumbrae (80–20%, with 100%=2*dose at inflection point; SAD 80cm; 10cm depth) parallel / perpendicular to leaf motion were 2.87/2.64mm for the smallest (0×76×0.75cm{sup 2}) and 5.34/4.94mm for the largest (9.76×9.75cm{sup 2}) square field. MLC circular field penumbrae exceeded fixed cones by 10–20% (e.g. 60mm: 4.0 vs. 3.6mm; 20mm: 3.6 vs. 2.9mm). Interleaf leakage was <0.5%. Clinically accessible workspace with MLC covered (non-coplanar) gantry angles of [-113°;+112°] (cranial) and [-108°;+102°] (body), and collimator angles of [-100°;+107°] (cranial) and [-91°;+100°] (body). Average leaf position offsets were ≤0.2mm in 14 standard A/P Bayouth tests and ≤0.6mm in 8 non-standard direction tests. Pre-test MLC exercise increased jaggedness (range ±0.3mm vs. ±0.5mm) and allowed to identify one malfunctioning leaf motor. Total system accuracy with MLC was 0.39±0.06mm in 6 End-to-End tests. Picket-Fence and AQA showed no adverse trends during the test period. Conclusion: The Incise™ MLC for CyberKnife M6™ displayed high accuracy and mechanical stability over the test period. The specific CyberKnife geometry and performance after exercise demand dedicated QA measures. This work is in part funded by a research grant from Accuray Inc, Sunnyvale, USA. Erasmus MC Cancer Institute also has research collaborations with Elekta AB, Stockholm, Sweden. C Fuerweger has previously received speaker honoraria from Accuray Inc, Sunnyvale, USA.

  8. The fish (IMRT) needs a bicycle (MLC)? The bicycle factories seem flourishing; not so the goldfish-bowl factories.

    PubMed

    Webb, S

    2011-07-01

    In this brief letter the arguments of Sherouse in 2002, that the delivery of intensity-modulated radiation therapy (IMRT) does not necessarily require a multileaf collimator (MLC), are extended with specific reference to the possibility to use the jaws-only (JO) of an accelerator or some moving mask. With reference to the work in the last decade to develop JO IMRT the argument is made that it is not just the limitations of JO that are precluding its commercial development but also the commercial/business and reimbursement situations. A new moving-mask-IMRT technique that has high monitor-unit (MU) efficiency, but low MU per component, is illustrated. The letter is intended to stimulate debate and is not a criticism by the author of current MLC-based IMRT. PMID:21292523

  9. Comparison of two Classification methods (MLC and SVM) to extract land use and land cover in Johor Malaysia

    NASA Astrophysics Data System (ADS)

    Rokni Deilmai, B.; Ahmad, B. Bin; Zabihi, H.

    2014-06-01

    Mapping is essential for the analysis of the land use and land cover, which influence many environmental processes and properties. For the purpose of the creation of land cover maps, it is important to minimize error. These errors will propagate into later analyses based on these land cover maps. The reliability of land cover maps derived from remotely sensed data depends on an accurate classification. In this study, we have analyzed multispectral data using two different classifiers including Maximum Likelihood Classifier (MLC) and Support Vector Machine (SVM). To pursue this aim, Landsat Thematic Mapper data and identical field-based training sample datasets in Johor Malaysia used for each classification method, which results indicate in five land cover classes forest, oil palm, urban area, water, rubber. Classification results indicate that SVM was more accurate than MLC. With demonstrated capability to produce reliable cover results, the SVM methods should be especially useful for land cover classification.

  10. A dosimetric evaluation of the Eclipse AAA algorithm and Millennium 120 MLC for cranial intensity-modulated radiosurgery

    SciTech Connect

    Calvo Ortega, Juan Francisco Moragues, Sandra; Pozo, Miquel; José, Sol San; Puertas, Enrique; Fernández, Jaime; Casals, Joan

    2014-07-01

    The aim of this study is to assess the accuracy of a convolution-based algorithm (anisotropic analytical algorithm [AAA]) implemented in the Eclipse planning system for intensity-modulated radiosurgery (IMRS) planning of small cranial targets by using a 5-mm leaf-width multileaf collimator (MLC). Overall, 24 patient-based IMRS plans for cranial lesions of variable size (0.3 to 15.1 cc) were planned (Eclipse, AAA, version 10.0.28) using fixed field-based IMRS produced by a Varian linear accelerator equipped with a 120 MLC (5-mm width on central leaves). Plan accuracy was evaluated according to phantom-based measurements performed with radiochromic film (EBT2, ISP, Wayne, NJ). Film 2D dose distributions were performed with the FilmQA Pro software (version 2011, Ashland, OH) by using the triple-channel dosimetry method. Comparison between computed and measured 2D dose distributions was performed using the gamma method (3%/1 mm). Performance of the MLC was checked by inspection of the DynaLog files created by the linear accelerator during the delivery of each dynamic field. The absolute difference between the calculated and measured isocenter doses for all the IMRS plans was 2.5% ± 2.1%. The gamma evaluation method resulted in high average passing rates of 98.9% ± 1.4% (red channel) and 98.9% ± 1.5% (blue and green channels). DynaLog file analysis revealed a maximum root mean square error of 0.46 mm. According to our results, we conclude that the Eclipse/AAA algorithm provides accurate cranial IMRS dose distributions that may be accurately delivered by a Varian linac equipped with a Millennium 120 MLC.

  11. Immunosuppressant MPA Modulates Tight Junction through Epigenetic Activation of MLCK/MLC-2 Pathway via p38MAPK

    PubMed Central

    Khan, Niamat; Pantakani, D. V. Krishna; Binder, Lutz; Qasim, Muhammad; Asif, Abdul R.

    2015-01-01

    Background: Mycophenolic acid (MPA) is an important immunosuppressive drug (ISD) prescribed to prevent graft rejection in the organ transplanted patients, however, its use is also associated with adverse side effects like sporadic gastrointestinal (GI) disturbances. Recently, we reported the MPA induced tight junctions (TJs) deregulation which involves MLCK/MLC-2 pathway. Here, we investigated the global histone acetylation as well as gene-specific chromatin signature of several genes associated with TJs regulation in Caco-2 cells after MPA treatment. Results: The epigenetic analysis shows that MPA treatment increases the global histone acetylation levels as well as the enrichment for transcriptional active histone modification mark (H3K4me3) at promoter regions of p38MAPK, ATF-2, MLCK, and MLC-2. In contrast, the promoter region of occludin was enriched for transcriptional repressive histone modification mark (H3K27me3) after MPA treatment. In line with the chromatin status, MPA treatment increased the expression of p38MAPK, ATF-2, MLCK, and MLC-2 both at transcriptional and translational level, while occludin expression was negatively influenced. Interestingly, the MPA induced gene expression changes and functional properties of Caco-2 cells could be blocked by the inhibition of p38MAPK using a chemical inhibitor (SB203580). Conclusions: Collectively, our results highlight that MPA disrupts the structure of TJs via p38MAPK-dependent activation of MLCK/MLC-2 pathway that results in decreased integrity of Caco-2 monolayer. These results led us to suggest that p38MAPK-mediated lose integrity of epithelial monolayer could be the possible cause of GI disturbance (barrier dysfunction) in the intestine, leading to leaky style diarrhea observed in the organ-transplanted patients treated with MPA. PMID:26733876

  12. Going Green and Using Less Paper to Print Exams: Student Performance, Completion Time, and Preference

    ERIC Educational Resources Information Center

    O'Connor, Kevin J.

    2014-01-01

    Two studies measured the impact on student exam performance and exam completion time of strategies aimed to reduce the amount of paper used for printing multiple-choice course exams. Study 1 compared single-sided to double-sided printed exams. Study 2 compared a single-column arrangement of multiple-choice answer options to a space (and paper)…

  13. The Preparatory Workshop: A Partial Solution to an English Compulsory Exam Failure Rate.

    ERIC Educational Resources Information Center

    Naugle, Helen; McGuire, Peter

    Georgia Institute of Technology has created a preparatory workshop that avoids focusing composition courses on the state competency exam while helping its students pass the exam. In checking the exams of students who had failed, three problems appeared: lack of motivation, lack of awareness of the standards for grading the exam, and an inability…

  14. Going Green and Using Less Paper to Print Exams: Student Performance, Completion Time, and Preference

    ERIC Educational Resources Information Center

    O'Connor, Kevin J.

    2014-01-01

    Two studies measured the impact on student exam performance and exam completion time of strategies aimed to reduce the amount of paper used for printing multiple-choice course exams. Study 1 compared single-sided to double-sided printed exams. Study 2 compared a single-column arrangement of multiple-choice answer options to a space (and paper)

  15. Experimental verification of a Monte Carlo-based MLC simulation model for IMRT dose calculations in heterogeneous media

    NASA Astrophysics Data System (ADS)

    Tyagi, N.; Curran, B. H.; Roberson, P. L.; Moran, J. M.; Acosta, E.; Fraass, B. A.

    2008-02-01

    IMRT often requires delivering small fields which may suffer from electronic disequilibrium effects. The presence of heterogeneities, particularly low-density tissues in patients, complicates such situations. In this study, we report on verification of the DPM MC code for IMRT treatment planning in heterogeneous media, using a previously developed model of the Varian 120-leaf MLC. The purpose of this study is twofold: (a) design a comprehensive list of experiments in heterogeneous media for verification of any dose calculation algorithm and (b) verify our MLC model in these heterogeneous type geometries that mimic an actual patient geometry for IMRT treatment. The measurements have been done using an IMRT head and neck phantom (CIRS phantom) and slab phantom geometries. Verification of the MLC model has been carried out using point doses measured with an A14 slim line (SL) ion chamber inside a tissue-equivalent and a bone-equivalent material using the CIRS phantom. Planar doses using lung and bone equivalent slabs have been measured and compared using EDR films (Kodak, Rochester, NY).

  16. Dosimetric comparison between two MLC systems commonly used for stereotactic radiosurgery and radiotherapy: a Monte Carlo and experimental study.

    PubMed

    Asnaashari, K; Chow, James C L; Heydarian, Mostafa

    2013-06-01

    In this work dosimetric parameters of two multi-leaf collimator (MLC) systems, namely the beam modulator (BM), which is the MLC commercial name for Elekta "Synergy S" linear accelerator and Radionics micro-MLC (MMLC), are compared using measurements and Monte Carlo simulations. Dosimetric parameters, such as percentage depth doses (PDDs), in-plane and cross-plane dose profiles, and penumbras for different depths and field sizes of the 6 MV photon beams were measured using ionization chamber and a water tank. The collimator leakages were measured using radiographic films. MMLC and BM were modeled using the EGSnrc-based BEAMnrc Monte Carlo code and above dosimetric parameters were calculated. The energy fluence spectra for the two MLCs were also determined using the BEAMnrc and BEAMDP. Dosimetric parameters of the two MLCs were similar, except for penumbras. Leaf-side and leaf-end 80-20% dose penumbras at 10 cm depth for a 10×10 cm(2) field size were 4.8 and 5.1mm for MMLC and 5.3 mm and 6.3 mm for BM, respectively. Both Radionics MMLC and Elekta BM can be used effectively based on their dosimetric characteristics for stereotactic radiosurgery and radiotherapy, although the former showed slightly sharper dose penumbra especially in the leaf-end direction. PMID:22658764

  17. Will students pass a competitive exam that they failed in their dreams?

    PubMed

    Arnulf, Isabelle; Grosliere, Laure; Le Corvec, Thibault; Golmard, Jean-Louis; Lascols, Olivier; Duguet, Alexandre

    2014-10-01

    We tested whether dreams can anticipate a stressful exam and how failure/success in dreams affect next-day performance. We collected information on students' dreams during the night preceding the medical school entrance exam. Demographic, academic, sleep and dream characteristics were compared to the students' grades on the exam. Of the 719 respondents to the questionnaire (of 2324 total students), 60.4% dreamt of the exam during the night preceding it. Problems with the exam appeared in 78% of dreams and primarily involved being late and forgetting answers. Reporting a dream about the exam on the pre-exam night was associated with better performance on the exam (p=.01). The frequency of dreams concerning the exam during the first term predicted proportionally higher performance on the exam (R=0.1, p=.01). These results suggest that the negative anticipation of a stressful event in dreams is common and that this episodic simulation provides a cognitive gain. PMID:25108280

  18. A new algorithm for determining collimator angles that favor efficiency in MLC based IMRT delivery.

    PubMed

    Wang, David; Hill, R W; Lam, S

    2004-05-01

    A new algorithm to determine collimator angles that favor delivery efficiency of intensity modulated radiotherapy plans was developed. It was found that the number of segments and monitor units (MUs) were largely reduced with the set of collimator angles determined with the new algorithm without compromising plan quality. The improvement of delivery efficiency using the new algorithm depends on the size and shape of the target(s), the number of modulation levels, and the type of leaf-sequencing algorithm. In a typical prostate case, when a sweeping leaf-sequencer is used for Varian 120 leaf (0.5 x 0.5 cm2 beamlet), 80 leaf (1 x 1 cm2 beamlet) and Elekta 40 leaf (1 x 1 cm2 beamlet), the number of segments was reduced by 42%, 29%, and 5%, respectively. The number of MUs was reduced by 41%, 35%, and 10%. For the Siemens MLC (IMFAST leaf sequencer, 1 x 1 cm2 beamlet) the segment reduction was 32% and the MU reduction was 14%. Comparison of the plans using the new and Brahme algorithms, in terms of target conformity index and dose volume histogram of the organs at risk, showed that the quality of the plans using the new algorithm was uncompromised. Similar results were obtained for a set of head and neck treatment plans. PMID:15191316

  19. Monte Carlo modeling and simulations of the High Definition (HD120) micro MLC and validation against measurements for a 6 MV beam

    SciTech Connect

    Borges, C.; Zarza-Moreno, M.; Heath, E.; Teixeira, N.; Vaz, P.

    2012-01-15

    Purpose: The most recent Varian micro multileaf collimator (MLC), the High Definition (HD120) MLC, was modeled using the BEAMNRC Monte Carlo code. This model was incorporated into a Varian medical linear accelerator, for a 6 MV beam, in static and dynamic mode. The model was validated by comparing simulated profiles with measurements. Methods: The Varian Trilogy (2300C/D) accelerator model was accurately implemented using the state-of-the-art Monte Carlo simulation program BEAMNRC and validated against off-axis and depth dose profiles measured using ionization chambers, by adjusting the energy and the full width at half maximum (FWHM) of the initial electron beam. The HD120 MLC was modeled by developing a new BEAMNRC component module (CM), designated HDMLC, adapting the available DYNVMLC CM and incorporating the specific characteristics of this new micro MLC. The leaf dimensions were provided by the manufacturer. The geometry was visualized by tracing particles through the CM and recording their position when a leaf boundary is crossed. The leaf material density and abutting air gap between leaves were adjusted in order to obtain a good agreement between the simulated leakage profiles and EBT2 film measurements performed in a solid water phantom. To validate the HDMLC implementation, additional MLC static patterns were also simulated and compared to additional measurements. Furthermore, the ability to simulate dynamic MLC fields was implemented in the HDMLC CM. The simulation results of these fields were compared with EBT2 film measurements performed in a solid water phantom. Results: Overall, the discrepancies, with and without MLC, between the opened field simulations and the measurements using ionization chambers in a water phantom, for the off-axis profiles are below 2% and in depth-dose profiles are below 2% after the maximum dose depth and below 4% in the build-up region. On the conditions of these simulations, this tungsten-based MLC has a density of 18.7 g cm{sup -3} and an overall leakage of about 1.1 {+-} 0.03%. The discrepancies between the film measured and simulated closed and blocked fields are below 2% and 8%, respectively. Other measurements were performed for alternated leaf patterns and the agreement is satisfactory (to within 4%). The dynamic mode for this MLC was implemented and the discrepancies between film measurements and simulations are within 4%. Conclusions: The Varian Trilogy (2300 C/D) linear accelerator including the HD120 MLC was successfully modeled and simulated using the Monte Carlo BEAMNRC code by developing an independent CM, the HDMLC CM, either in static and dynamic modes.

  20. An MLC-based linac QA procedure for the characterization of radiation isocenter and room lasers' position

    SciTech Connect

    Rosca, Florin; Lorenz, Friedlieb; Hacker, Fred L.; Chin, Lee M.; Ramakrishna, Naren; Zygmanski, Piotr

    2006-06-15

    We have designed and implemented a new stereotactic linac QA test with stereotactic precision. The test is used to characterize gantry sag, couch wobble, cone placement, MLC offsets, and room lasers' positions relative to the radiation isocenter. Two MLC star patterns, a cone pattern, and the laser line patterns are recorded on the same imaging medium. Phosphor plates are used as imaging medium due to their sensitivity to red light. The red light of room lasers erases some of the irradiation information stored on the phosphor plates enabling accurate and direct measurements for the position of room lasers and radiation isocenter. Using film instead of the phosphor plate as imaging medium is possible, however, it is less practical. The QA method consists of irradiating four phosphor plates that record the gantry sag between the 0 deg.and 180 deg.gantry angles, the position and stability of couch rotational axis, the sag between the 90 deg.and 270 deg.gantry angles, the accuracy of cone placement on the collimator, the MLC offsets from the collimator rotational axis, and the position of laser lines relative to the radiation isocenter. The estimated accuracy of the method is {+-}0.2 mm. The observed reproducibility of the method is about {+-}0.1 mm. The total irradiation/illumination time is about 10 min per image. Data analysis, including the phosphor plate scanning, takes less than 5 min for each image. The method characterizes the radiation isocenter geometry with the high accuracy required for the stereotactic radiosurgery. In this respect, it is similar to the standard ball test for stereotactic machines. However, due to the usage of the MLC instead of the cross-hair/ball, it does not depend on the cross-hair/ball placement errors with respect to the lasers and it provides more information on the mechanical integrity of the linac/couch/laser system. Alternatively, it can be used as a highly accurate QA procedure for the nonstereotactic machines. Noteworthy is its ability to characterize the MLC position accuracy, which is an important factor in IMRT delivery.

  1. An algorithm for shifting MLC shapes to adjust for daily prostate movement during concurrent treatment with pelvic lymph nodes

    SciTech Connect

    Ludlum, Erica; Mu, Guangwei; Weinberg, Vivian; Roach, Mack III; Verhey, Lynn J.; Xia Ping

    2007-12-15

    Concurrent treatment of the prostate and the pelvic lymph nodes encounters the problem of the prostate gland moving independently from the pelvic lymph nodes on a daily basis. The purpose of this study is to develop a leaf-tracking algorithm for adjustment of IMRT portals without requirement of online dose calculation to account for daily prostate position during concurrent treatment with pelvic lymph nodes. A leaf-shifting algorithm was developed and programmed to adjust the positions of selected MLC leaf pairs according to prostate movement in the plane perpendicular to each beam angle. IMRT plans from five patients with concurrent treatment of the prostate and pelvic lymph nodes were selected to test the feasibility of this algorithm by comparison with isocenter-shifted plans, using defined dose endpoints. When the prostate moved 0.5, 1.0, and 1.5 cm along the anterior/posterior direction, the average doses to 95% of the prostate (D{sub 95%}) for the iso-shift plans were similar to the MLC-shift plans, (54.7, 54.4, and 54.1 Gy versus 54.5, 54.3, and 53.9 Gy, respectively). The corresponding D{sub 95%} averages to the pelvic lymph nodes were reduced from the prescription dose of 45 Gy to 42.7, 38.3, and 34.0 Gy for iso-shift plans (p=0.04 for each comparison), while the D{sub 95%} averages for the MLC-shift plans did not significantly differ from the prescription dose, at 45.0, 44.8, and 44.5 Gy. Compensation for prostate movement along the superior/inferior direction was more complicated due to a limiting MLC leaf width of 1.0 cm. In order to concurrently treat the prostate and pelvic lymph nodes with the prostate moving independently, shifting selected MLC leaf pairs may be a more practical adaptive solution than shifting the patient.

  2. Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking

    SciTech Connect

    Yoon, Jai-Woong; Sawant, Amit; Suh, Yelin; Cho, Byung-Chul; Suh, Tae-Suk; Keall, Paul

    2011-07-15

    Purpose: In dynamic multileaf collimator (MLC) motion tracking with complex intensity-modulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average algorithm compared with real-time tracking and no compensation beam delivery is described. Methods: The properties of the moving average algorithm were measured and compared with those of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy, and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a {gamma}-test with a 3%/3 mm criterion. Results: The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%-100% for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7-1.1 mm for real-time tracking, and 3.7-7.2 mm for no compensation. The percentage of dosimetric points failing the {gamma}-test ranged from 4 to 30% for moving average tracking, 0%-23% for real-time tracking, and 10%-47% for no compensation. Conclusions: The delivery efficiency of moving average tracking was up to four times higher than that of real-time tracking and approached the efficiency of no compensation for all cases. The geometric accuracy and dosimetric accuracy of the moving average algorithm was between real-time tracking and no compensation, approximately half the percentage of dosimetric points failing the {gamma}-test compared with no compensation.

  3. Analysis of direct clinical consequences of MLC positional errors in volumetric-modulated arc therapy using 3D dosimetry system.

    PubMed

    Nithiyanantham, Karthikeyan; Mani, Ganesh K; Subramani, Vikraman; Mueller, Lutz; Palaniappan, Karrthick K; Kataria, Tejinder

    2015-01-01

    In advanced, intensity-modulated external radiotherapy facility, the multileaf collimator has a decisive role in the beam modulation by creating multiple segments or dynamically varying field shapes to deliver a uniform dose distribution to the target with maximum sparing of normal tissues. The position of each MLC leaf has become more critical for intensity-modulated delivery (step-and-shoot IMRT, dynamic IMRT, and VMAT) compared to 3D CRT, where it defines only field boundaries. We analyzed the impact of the MLC positional errors on the dose distribution for volumetric-modulated arc therapy, using a 3D dosimetry system. A total of 15 VMAT cases, five each for brain, head and neck, and prostate cases, were retrospectively selected for the study. All the plans were generated in Monaco 3.0.0v TPS (Elekta Corporation, Atlanta, GA) and delivered using Elekta Synergy linear accelerator. Systematic errors of +1, +0.5, +0.3, 0, -1, -0.5, -0.3 mm were introduced in the MLC bank of the linear accelerator and the impact on the dose distribution of VMAT delivery was measured using the COMPASS 3D dosim-etry system. All the plans were created using single modulated arcs and the dose calculation was performed using a Monte Carlo algorithm in a grid size of 3 mm. The clinical endpoints D95%, D50%, D2%, and Dmax,D20%, D50% were taken for the evaluation of the target and critical organs doses, respectively. A significant dosimetric effect was found for many cases even with 0.5 mm of MLC positional errors. The average change of dose D 95% to PTV for ± 1 mm, ± 0.5 mm, and ±0.3mm was 5.15%, 2.58%, and 0.96% for brain cases; 7.19%, 3.67%, and 1.56% for head and neck cases; and 8.39%, 4.5%, and 1.86% for prostate cases, respectively. The average deviation of dose Dmax was 5.4%, 2.8%, and 0.83% for brainstem in brain cases; 8.2%, 4.4%, and 1.9% for spinal cord in H&N; and 10.8%, 6.2%, and 2.1% for rectum in prostate cases, respectively. The average changes in dose followed a linear relationship with the amount of MLC positional error, as can be expected. MLC positional errors beyond ± 0.3 mm showed a significant influence on the intensity-modulated dose distributions. It is, therefore, recommended to have a cautious MLC calibration procedure to sufficiently meet the accuracy in dose delivery. PMID:26699311

  4. Ethics versus education: pelvic exams on anesthetized women.

    PubMed

    Schniederjan, Stephanie; Donovan, G Kevin

    2005-08-01

    In a survey of junior and senior medical students at the University of Oklahoma, a large majority of respondents reported having performed pelvic exams on anesthetized gynecologic surgery patients. Nearly three-quarters also reported believing that these patients had not specifically consented to undergo exams by students during their surgical procedures. While some students and medical educators maintain that pelvic exams under anesthesia are necessary for the development of students' examination skills, this assertion has not gone unquestioned. Serious ethical concerns have been raised by members of the medical community and women's advocacy groups, and the practice was recently outlawed in one state. Despite this widespread opposition, non-consented pelvic examinations evidently remain a common practice in US teaching hospitals. Our consideration of this controversial issue leads us to conclude that explicit, informed consent must be obtained in order for pelvic examinations to be performed on surgical patients, or risk compromising the doctor-patient relationship. PMID:16206868

  5. Using collaborative group exams to investigate students' ability to learn

    NASA Astrophysics Data System (ADS)

    Lin, Yuhfen; Brookes, David T.

    2013-01-01

    One of our primary learning goals for our students is: we would like them to be able to learn physics on their own. Unfortunately few existing assessments can assess students' ability to learn without being taught. We are developing a new format of exam which challenges students to work together as a class to tackle a difficult problem that requires them to learn new physics. Rather than restrict their activities, we offer them a resource-rich environment of textbooks and internet access. Students are required to transfer their knowledge by answering a related question on a more standard "individual exam" two days later. In this paper we will discuss the format of the exams, background theory, and present evidence of how students are able to learn new physics on their own. Our results show that although students struggle at first, they do surprisingly well once they get used to the format.

  6. Development of an iterative reconstruction method to overcome 2D detector low resolution limitations in MLC leaf position error detection for 3D dose verification in IMRT

    NASA Astrophysics Data System (ADS)

    Visser, R.; Godart, J.; Wauben, D. J. L.; Langendijk, J. A.; van’t Veld, A. A.; Korevaar, E. W.

    2016-05-01

    The objective of this study was to introduce a new iterative method to reconstruct multi leaf collimator (MLC) positions based on low resolution ionization detector array measurements and to evaluate its error detection performance. The iterative reconstruction method consists of a fluence model, a detector model and an optimizer. Expected detector response was calculated using a radiotherapy treatment plan in combination with the fluence model and detector model. MLC leaf positions were reconstructed by minimizing differences between expected and measured detector response. The iterative reconstruction method was evaluated for an Elekta SLi with 10.0 mm MLC leafs in combination with the COMPASS system and the MatriXX Evolution (IBA Dosimetry) detector with a spacing of 7.62 mm. The detector was positioned in such a way that each leaf pair of the MLC was aligned with one row of ionization chambers. Known leaf displacements were introduced in various field geometries ranging from  ‑10.0 mm to 10.0 mm. Error detection performance was tested for MLC leaf position dependency relative to the detector position, gantry angle dependency, monitor unit dependency, and for ten clinical intensity modulated radiotherapy (IMRT) treatment beams. For one clinical head and neck IMRT treatment beam, influence of the iterative reconstruction method on existing 3D dose reconstruction artifacts was evaluated. The described iterative reconstruction method was capable of individual MLC leaf position reconstruction with millimeter accuracy, independent of the relative detector position within the range of clinically applied MU’s for IMRT. Dose reconstruction artifacts in a clinical IMRT treatment beam were considerably reduced as compared to the current dose verification procedure. The iterative reconstruction method allows high accuracy 3D dose verification by including actual MLC leaf positions reconstructed from low resolution 2D measurements.

  7. Development of an iterative reconstruction method to overcome 2D detector low resolution limitations in MLC leaf position error detection for 3D dose verification in IMRT.

    PubMed

    Visser, R; Godart, J; Wauben, D J L; Langendijk, J A; Van't Veld, A A; Korevaar, E W

    2016-05-21

    The objective of this study was to introduce a new iterative method to reconstruct multi leaf collimator (MLC) positions based on low resolution ionization detector array measurements and to evaluate its error detection performance. The iterative reconstruction method consists of a fluence model, a detector model and an optimizer. Expected detector response was calculated using a radiotherapy treatment plan in combination with the fluence model and detector model. MLC leaf positions were reconstructed by minimizing differences between expected and measured detector response. The iterative reconstruction method was evaluated for an Elekta SLi with 10.0 mm MLC leafs in combination with the COMPASS system and the MatriXX Evolution (IBA Dosimetry) detector with a spacing of 7.62 mm. The detector was positioned in such a way that each leaf pair of the MLC was aligned with one row of ionization chambers. Known leaf displacements were introduced in various field geometries ranging from  -10.0 mm to 10.0 mm. Error detection performance was tested for MLC leaf position dependency relative to the detector position, gantry angle dependency, monitor unit dependency, and for ten clinical intensity modulated radiotherapy (IMRT) treatment beams. For one clinical head and neck IMRT treatment beam, influence of the iterative reconstruction method on existing 3D dose reconstruction artifacts was evaluated. The described iterative reconstruction method was capable of individual MLC leaf position reconstruction with millimeter accuracy, independent of the relative detector position within the range of clinically applied MU's for IMRT. Dose reconstruction artifacts in a clinical IMRT treatment beam were considerably reduced as compared to the current dose verification procedure. The iterative reconstruction method allows high accuracy 3D dose verification by including actual MLC leaf positions reconstructed from low resolution 2D measurements. PMID:27100169

  8. Effect of paper color on students' physics exam performances

    NASA Astrophysics Data System (ADS)

    Schmidt, David R.; Ruskell, Todd G.; Kohl, Patrick B.

    2013-01-01

    Prior work has established the existence of a color-performance relationship in achievement contexts and has demonstrated its presence in some undergraduate course examinations. This study examines the manifestation of such a relationship in an introductory, 430-student, calculus-based electricity and magnetism course during which the paper color used in examinations was varied. In this report, we analyze three separate exams and differentiate between students' multiple choice, written response, conceptual, and computational performances. Also considered are factors such as the time students require to complete exams and their confidence levels prior to and immediately following assessment. Performance in all categories appears to be independent of paper color.

  9. Database trial impact on graduate nursing comprehensive exams.

    PubMed

    Pionke, Katharine; Huckstadt, Alicia

    2015-10-01

    While the authors were doing a test period of databases, the question of whether or not databases affect outcomes of graduate nursing comprehensive examinations came up. This study explored that question through using citation analysis of exams that were taken during a database trial and exams that were not. The findings showed no difference in examination pass/fail rates. While the pass/fail rates did not change, a great deal was learned in terms of citation accuracy and types of materials that students used, leading to discussions about changing how citation and plagiarism awareness were taught. PMID:26512218

  10. SU-E-T-175: Evaluation of the Relative Output Ratio for Collimator Jaw and MLC Defined Small Static 6MV Photon Fields

    SciTech Connect

    Cho, G; Thwaites, D

    2014-06-01

    Purpose: To evaluate relative output ratio of collimator jaw and MLC defined small photon fields. Methods: Relative output ratios were measured using Gafchromic EBT3 film for a 6 MV photon beam on a Novalis Tx with HD120 MLC. Beam collimation was achieved by the jaws for 1.0 cm and 3.0 cm and MLC defined square field sizes between 0.5 cm and 1.0 cm with varying jaw settings between 2.0 and 4.0 cm. Film pieces were exposed to 4 Gy. Experiments were repeated with each session consisting of five consecutive exposures for the given MLC and/or jaw collimation and with the MLC and the jaws reset for each exposure. Films were scanned using EPSON 10000XL flatbed scanner approximately 24 hours after exposure in 48 bit RGB format at 150 dpi. Film calibration data were corrected for daily linac output variations. Doses were evaluated using the green channel with square ROI sizes of 0.1 – 0.6 cm. Converted doses were normalised for output ratio calculation using the 3.0 cm field as a machine specific reference field size. Mean output ratio and coefficient of variation (CV) were calculated for each experimental session. Results: For the Novalis 6 MV photon beam the output ratios between 0.719 and 0.872 have been measured for the jaw/MLC combinations tested. For a jaw setting of 4.0 cm field, the mean CV of the output ratios increased from 0.77% to 1.48% with decreasing MLC field size from 1.0 cm to 0.5 cm. For a nominal MLC 1.0 cm field, the CV increased to 1.00% from 0.77% with reducing jaw field size from 4.0 cm to 2.0 cm. Conclusion: The relative output ratio and the associated CV were dependent on the collimator jaw and MLC settings. The field size dependent CV showed similar trends to those reported in the literature.

  11. Doppler ultrasound exam of an arm or leg

    MedlinePlus

    This test uses ultrasound to look at the blood flow in the large arteries and veins in the arms and legs. ... The test is done in the ultrasound or radiology department or in a ... the exam: A water-soluble gel is placed on a handheld device ...

  12. Cheating on Exams: The Case of Israeli Students

    ERIC Educational Resources Information Center

    Siniver, Erez

    2013-01-01

    The phenomenon of cheating on exams, which harms both the reputation of an academic institution and the students who don't cheat, is becoming increasingly common. We attempt to shed light on this phenomenon using data from a survey of graduates of the College of Management Academic Studies in Israel. Three aspects of the problem are examined:…

  13. The New AP Chemistry Exam: Its Rationale, Content, and Scoring

    ERIC Educational Resources Information Center

    Price, Paul D.; Kugel, Roger W.

    2014-01-01

    The 2013-2014 academic year marks the rollout of the redesigned advanced placement (AP) chemistry course and exam. There have been many questions as to why the course was redesigned and how the new examination will differ from its legacy version. In this article we give a brief overview of the legacy course and examine why a redesign occurred in…

  14. Interteaching: The Effects of Quality Points on Exam Scores

    ERIC Educational Resources Information Center

    Saville, Bryan K.; Zinn, Tracy E.

    2009-01-01

    Although previous studies have found interteaching to be an effective alternative to traditional methods of instruction, few studies have examined which of its components contribute to its effectiveness. In the current study, we examined whether manipulating quality points had an effect on our students' exam scores. In two sections of an

  15. Tougher Exam for GED Spurs Ups and Downs

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2004-01-01

    Participation in the GED testing program plunged by nearly 44 percent during the most recent recorded year, a drop-off that the exam's sponsor attributes to an earlier rush by teenagers and adults to secure high school diplomas through the test before its minimum passing scores were raised. The overall number of teenagers and adults who took the…

  16. Equating National Exams in Foreign Language Reading Comprehension.

    ERIC Educational Resources Information Center

    Krieken, Robert van

    The procedures for the construction of the Dutch national exams of reading comprehension and for setting cut-off scores have remained roughly unchanged over 20 years. Construction procedures are characterized by thorough screening rather than pretesting; cut-off scores are influenced by procedures and percentages fails rather than by equating. Two…

  17. Teachers' Interpretations of Exit Exam Scores and College Readiness

    ERIC Educational Resources Information Center

    McIntosh, Shelby

    2013-01-01

    This study examined teachers' interpretations of Virginia's high school exit exam policy through the teachers' responses to a survey. The survey was administered to teachers from one school district in Northern Virginia. The teachers selected for the survey taught a subject in which students must pass a Standards of Learning (SOL) test in order to…

  18. Preparticipation Exams: How to Detect a Teenage Crisis.

    ERIC Educational Resources Information Center

    Donahue, Parnell

    1990-01-01

    Sport-specific preparticipation examinations do not address social problems (drug abuse, suicide, murder, accidents, and sex) epidemic among teenagers, but they are often the only contact these youth have with a physician. This article discusses these risk factors and presents methods for assessing them during preparticipation exams. (SM)

  19. Cheating on Exams: The Case of Israeli Students

    ERIC Educational Resources Information Center

    Siniver, Erez

    2013-01-01

    The phenomenon of cheating on exams, which harms both the reputation of an academic institution and the students who don't cheat, is becoming increasingly common. We attempt to shed light on this phenomenon using data from a survey of graduates of the College of Management Academic Studies in Israel. Three aspects of the problem are examined:

  20. Using Oral Exams to Assess Communication Skills in Business Courses

    ERIC Educational Resources Information Center

    Burke-Smalley, Lisa A.

    2014-01-01

    Business, like many other fields in higher education, continues to rely largely on conventional testing methods for assessing student learning. In the current article, another evaluation approach--the oral exam--is examined as a means for building and evaluating the professional communication and oral dialogue skills needed and utilized by…

  1. From Exam Factories to Communities of Discovery: The Democratic Route

    ERIC Educational Resources Information Center

    Coffield, Frank; Williamson, Bill

    2011-01-01

    "From Exam Factories to Communities of Discovery" passionately calls for educators to challenge the dominant market-led model of education and instead build a more democratic one, better able to face threats such as environmental damage; intensified global competition; corrosive social inequalities in and between nations in the world; and the need…

  2. Strategies Instruction to Improve the Preparation for English Oral Exams

    ERIC Educational Resources Information Center

    Abad, José Vicente; Alzate, Paula Andrea

    2016-01-01

    This article presents the results of an inter-institutional research study that assessed the impact of strategies instruction on students' preparation for and performance in oral exams. Two teacher-researchers at different universities trained 26 students in their respective B1-English-level courses in using language learning strategies. The study…

  3. The Effect of Quiz Timing on Exam Performance

    ERIC Educational Resources Information Center

    Hadsell, Lester

    2009-01-01

    The author reported on the effectiveness of online quizzes in introductory finance courses. He found completion of quizzes near the time when the teacher presents the material in class lectures to be associated with a moderate and statistically significant increase in performance on exams. Feedback to students on their quiz performance did not…

  4. From Exam Factories to Communities of Discovery: The Democratic Route

    ERIC Educational Resources Information Center

    Coffield, Frank; Williamson, Bill

    2011-01-01

    "From Exam Factories to Communities of Discovery" passionately calls for educators to challenge the dominant market-led model of education and instead build a more democratic one, better able to face threats such as environmental damage; intensified global competition; corrosive social inequalities in and between nations in the world; and the need

  5. Examination of the Factors Influencing the Exam Results

    ERIC Educational Resources Information Center

    Sitku-Görömbei, Cecília

    2009-01-01

    The defectiveness of the effectiveness of the Hungarian general education revealed in the PISA survey appears in the higher education as well. The "Introduction to Informatics" subject has one of the lowest exam results among the students of the College of Nyíregyháza majoring in Computer Program Designer and Teacher of Computer Science.…

  6. Rumor Has It: Investigating Teacher Licensure Exam Advice Networks

    ERIC Educational Resources Information Center

    Baker-Doyle, Kira; Petchauer, Emery

    2015-01-01

    In many countries, including the United States, England, Korea, Hong Kong, and Japan, individuals must pass some form of examination for entry into or completion of a teacher education program (Wang, Coleman, Coley, & Phelps, 2003). These exams are meant to act as gatekeeping mechanisms for teacher quality. In the majority of the countries…

  7. Spanish-English Verbatim Translation Exam. Final Report.

    ERIC Educational Resources Information Center

    Stansfield, Charles W.; And Others

    The development and validation of the Spanish-English Verbatim Translation Exam (SEVTE) is described. The test is for use by the Federal Bureau of Investigation (FBI) in the selection of applicants for the positions of Language Specialist or Contract Linguist. The report is divided into eight sections. Section 1 describes the need for the test,…

  8. Residency Applicants Misinterpret Their United States Medical Licensing Exam Scores

    ERIC Educational Resources Information Center

    Jones, Roger C.; Desbiens, Norman A.

    2009-01-01

    Proper interpretation of the results of the United States Medical Licensing Exam (USMLE) is important for program directors, residents, and faculty who advise applicants about applying for residency positions. We suspected that applicants often misinterpreted their performance in relationship to others who took the same examination. In 2005, 54…

  9. State High School Exit Exams: A Policy in Transition

    ERIC Educational Resources Information Center

    McIntosh, Shelby

    2012-01-01

    Since 2002, the Center on Education Policy (CEP) at The George Washington University, a national advocate for public education and improving public schools, has been studying state high school exit examinations--tests students must pass to receive a high school diploma. This year marks the 11th year CEP has reported on exit exams in order to help…

  10. Your First Pelvic Exam: A Guide for Teens

    MedlinePlus

    ... need a pelvic exam if I’m a virgin? Even if you’re a virgin (you’ve never had vaginal intercourse), you may ... apart. This is usually the part when some young women feel embarrassed. Your HCP should make you ...

  11. Psychosocial Factors Associated with Skin Self-Exam Performance

    ERIC Educational Resources Information Center

    Jensen, Jakob D.; Moriarty, Cortney M.

    2008-01-01

    Objective: The authors examined psychosocial factors associated with skin self-exam (SSE) performance by young adults. Participants and Methods: The authors administered surveys to 218 US college students (aged 18-26 years) attending a large midwestern university. Results: Contrary to prior research, men (44%) and women (49%) were relatively…

  12. Unified (Russian) State Exam in English: Reading Comprehension Tasks

    ERIC Educational Resources Information Center

    Solnyshkina, Marina I.; Harkova, Elena V.; Kiselnikov, Aleksander S.

    2014-01-01

    The article summarizes the study of Reading Comprehension Tasks utilized in preparation for Unified (Russian) State Exam. The corpus of reading tasks was analyzed with the use of the classification algorithm developed by Weir and Urquhart (1998), and aimed at determining the level of engagement (local or global) and type of engagement (literal or…

  13. Tougher Exam for GED Spurs Ups and Downs

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2004-01-01

    Participation in the GED testing program plunged by nearly 44 percent during the most recent recorded year, a drop-off that the exam's sponsor attributes to an earlier rush by teenagers and adults to secure high school diplomas through the test before its minimum passing scores were raised. The overall number of teenagers and adults who took the

  14. State High School Tests: Exit Exams and Other Assessments

    ERIC Educational Resources Information Center

    Dietz, Shelby

    2010-01-01

    Since 2002, the Center on Education Policy (CEP), an independent nonprofit organization, has been studying state high school exit examinations--tests students must pass to receive a high school diploma. This is CEP's ninth annual report on exit exams. The information in this report comes from several sources: CEP's survey of states that have…

  15. Examing Proteins in a (VDA) Vapor Diffusion Apparatus

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Mission Specialist Marsha Ivins exams proteins in a Vapor Diffusion Apparatus (VDA) while working on a Protein Crystal Growth (PCG) experiment aboard STS-32. Each vapor diffusion device has a number of experiment chambers; each chamber contains a protein solution and precipating or crystallizing agent.

  16. Using Oral Exams to Assess Communication Skills in Business Courses

    ERIC Educational Resources Information Center

    Burke-Smalley, Lisa A.

    2014-01-01

    Business, like many other fields in higher education, continues to rely largely on conventional testing methods for assessing student learning. In the current article, another evaluation approach--the oral exam--is examined as a means for building and evaluating the professional communication and oral dialogue skills needed and utilized by

  17. Getting Interpersonal on a University Entrance Exam Impromptu Writing Task

    ERIC Educational Resources Information Center

    Myskow, Gordon; Gordon, Kana

    2012-01-01

    This article explores the types of audience engagement strategies used by a Japanese secondary school student in an after school course preparing for a high-stakes impromptu academic writing task on a university entrance exam. The study uses appraisal theory--the branch of Systemic Functional Linguistics (SFL) concerned with the patterning of…

  18. Determination of kQ using MLC-collimated rectangular fields for absolute dosimetry of the CyberKnife.

    PubMed

    Gersh, Jacob A; Willett, Benjamin

    2015-01-01

    Traditional CyberKnife (CK) calibration uses TG-51, which requires kQ to be defined using the standard reference condition of 100 cm SSD in a 10 cm × 10 cm field. Since the CK is calibrated using a 6 cm fixed-aperture collimating cone at 80 cm SAD, the BJR-25 method is commonly used to relate circular-field PDDs to square-field PDDs for kQ determination. Using the InCise MLC system, the CK is able to deliver rectangular fields, allowing a more direct measurement of %dd(10 cm) using conventional reference conditions. We define the PDD correction factor (CPDD) as the ratio of %dd(10 cm) measured using CK reference conditions to that measured using standard TG-51 reference conditions. Using four ionization chambers (A1SL, CC08, CC13, and A19), %dd(10 cm) is measured using a 6 cm fixed cone at 80 cm SSD and at 100 cm SSD using an effective 10 cm × 10 cm MLC-collimated field. These values are used to calculate CPDD, while the latter is used to directly calculate a kQ value. This direct kQ value is then compared to values determined using the BJR-25 method. Using the MLC system, this study demonstrates conversion between the %dd(10 cm) measured using CyberKnife reference conditions and TG-51 reference conditions. These values provide the means for derivation of a kQ curve as a function of direct measurements of %dd(10 cm) using a 6 cm fixed-aperture collimating cone at 80 cm SSD. PMID:26699583

  19. Structure of the Small Dictyostelium discoideum Myosin Light Chain MlcB Provides Insights into MyoB IQ Motif Recognition*

    PubMed Central

    Liburd, Janine; Chitayat, Seth; Crawley, Scott W.; Munro, Kim; Miller, Emily; Denis, Chris M.; Spencer, Holly L.; Ct, Graham P.; Smith, Steven P.

    2014-01-01

    Dictyostelium discoideum MyoB is a class I myosin involved in the formation and retraction of membrane projections, cortical tension generation, membrane recycling, and phagosome maturation. The MyoB-specific, single-lobe EF-hand light chain MlcB binds the sole IQ motif of MyoB with submicromolar affinity in the absence and presence of Ca2+. However, the structural features of this novel myosin light chain and its interaction with its cognate IQ motif remain uncharacterized. Here, we describe the NMR-derived solution structure of apoMlcB, which displays a globular four-helix bundle. Helix 1 adopts a unique orientation when compared with the apo states of the EF-hand calcium-binding proteins calmodulin, S100B, and calbindin D9k. NMR-based chemical shift perturbation mapping identified a hydrophobic MyoB IQ binding surface that involves amino acid residues in helices I and IV and the functional N-terminal Ca2+ binding loop, a site that appears to be maintained when MlcB adopts the holo state. Complementary mutagenesis and binding studies indicated that residues Ile-701, Phe-705, and Trp-708 of the MyoB IQ motif are critical for recognition of MlcB, which together allowed the generation of a structural model of the apoMlcB-MyoB IQ complex. We conclude that the mode of IQ motif recognition by the novel single-lobe MlcB differs considerably from that of stereotypical bilobal light chains such as calmodulin. PMID:24790102

  20. Structure of the small Dictyostelium discoideum myosin light chain MlcB provides insights into MyoB IQ motif recognition.

    PubMed

    Liburd, Janine; Chitayat, Seth; Crawley, Scott W; Munro, Kim; Miller, Emily; Denis, Chris M; Spencer, Holly L; Ct, Graham P; Smith, Steven P

    2014-06-13

    Dictyostelium discoideum MyoB is a class I myosin involved in the formation and retraction of membrane projections, cortical tension generation, membrane recycling, and phagosome maturation. The MyoB-specific, single-lobe EF-hand light chain MlcB binds the sole IQ motif of MyoB with submicromolar affinity in the absence and presence of Ca(2+). However, the structural features of this novel myosin light chain and its interaction with its cognate IQ motif remain uncharacterized. Here, we describe the NMR-derived solution structure of apoMlcB, which displays a globular four-helix bundle. Helix 1 adopts a unique orientation when compared with the apo states of the EF-hand calcium-binding proteins calmodulin, S100B, and calbindin D9k. NMR-based chemical shift perturbation mapping identified a hydrophobic MyoB IQ binding surface that involves amino acid residues in helices I and IV and the functional N-terminal Ca(2+) binding loop, a site that appears to be maintained when MlcB adopts the holo state. Complementary mutagenesis and binding studies indicated that residues Ile-701, Phe-705, and Trp-708 of the MyoB IQ motif are critical for recognition of MlcB, which together allowed the generation of a structural model of the apoMlcB-MyoB IQ complex. We conclude that the mode of IQ motif recognition by the novel single-lobe MlcB differs considerably from that of stereotypical bilobal light chains such as calmodulin. PMID:24790102

  1. Investigating the Effects of Exam Length on Performance and Cognitive Fatigue

    PubMed Central

    Jensen, Jamie L.; Berry, Dane A.; Kummer, Tyler A.

    2013-01-01

    This study examined the effects of exam length on student performance and cognitive fatigue in an undergraduate biology classroom. Exams tested higher order thinking skills. To test our hypothesis, we administered standard- and extended-length high-level exams to two populations of non-majors biology students. We gathered exam performance data between conditions as well as performance on the first and second half of exams within conditions. We showed that lengthier exams led to better performance on assessment items shared between conditions, possibly lending support to the spreading activation theory. It also led to greater performance on the final exam, lending support to the testing effect in creative problem solving. Lengthier exams did not result in lower performance due to fatiguing conditions, although students perceived subjective fatigue. Implications of these findings are discussed with respect to assessment practices. PMID:23950918

  2. Comparison of secondary neutron dose in proton therapy resulting from the use of a tungsten alloy MLC or a brass collimator system

    SciTech Connect

    Diffenderfer, Eric S.; Ainsley, Christopher G.; Kirk, Maura L.; McDonough, James E.; Maughan, Richard L.

    2011-11-15

    Purpose: To apply the dual ionization chamber method for mixed radiation fields to an accurate comparison of the secondary neutron dose arising from the use of a tungsten alloy multileaf collimator (MLC) as opposed to a brass collimator system for defining the shape of a therapeutic proton field. Methods: Hydrogenous and nonhydrogenous ionization chambers were constructed with large volumes to enable measurements of absorbed doses below 10{sup -4} Gy in mixed radiation fields using the dual ionization chamber method for mixed-field dosimetry. Neutron dose measurements were made with a nominal 230 MeV proton beam incident on a closed tungsten alloy MLC and a solid brass block. The chambers were cross-calibrated against a {sup 60}Co-calibrated Farmer chamber in water using a 6 MV x-ray beam and Monte Carlo simulations were performed to account for variations in ionization chamber response due to differences in secondary neutron energy spectra. Results: The neutron and combined proton plus {gamma}-ray absorbed doses are shown to be nearly equivalent downstream from either a closed tungsten alloy MLC or a solid brass block. At 10 cm downstream from the distal edge of the collimating material the neutron dose from the closed MLC was (5.3 {+-} 0.4) x 10{sup -5} Gy/Gy. The neutron dose with brass was (6.4 {+-} 0.7) x 10{sup -5} Gy/Gy. Further from the secondary neutron source, at 50 cm, the neutron doses remain close for both the MLC and brass block at (6.9 {+-} 0.6) x 10{sup -6} Gy/Gy and (6.3 {+-} 0.7) x 10{sup -6} Gy/Gy, respectively. Conclusions: The dual ionization chamber method is suitable for measuring secondary neutron doses resulting from proton irradiation. The results of measurements downstream from a closed tungsten alloy MLC and a brass block indicate that, even in an overly pessimistic worst-case scenario, secondary neutron production in a tungsten alloy MLC leads to absorbed doses that are nearly equivalent to those seen from brass collimators. Therefore, the choice of tungsten alloy in constructing the leaves of a proton MLC is appropriate, and does not lead to a substantial increase in the secondary neutron dose to the patient compared to that generated in a brass collimator.

  3. Dose-to-water conversion for the backscatter-shielded EPID: A frame-based method to correct for EPID energy response to MLC transmitted radiation

    SciTech Connect

    Zwan, Benjamin J. O’Connor, Daryl J.; King, Brian W.; Greer, Peter B.

    2014-08-15

    Purpose: To develop a frame-by-frame correction for the energy response of amorphous silicon electronic portal imaging devices (a-Si EPIDs) to radiation that has transmitted through the multileaf collimator (MLC) and to integrate this correction into the backscatter shielded EPID (BSS-EPID) dose-to-water conversion model. Methods: Individual EPID frames were acquired using a Varian frame grabber and iTools acquisition software then processed using in-house software developed inMATLAB. For each EPID image frame, the region below the MLC leaves was identified and all pixels in this region were multiplied by a factor of 1.3 to correct for the under-response of the imager to MLC transmitted radiation. The corrected frames were then summed to form a corrected integrated EPID image. This correction was implemented as an initial step in the BSS-EPID dose-to-water conversion model which was then used to compute dose planes in a water phantom for 35 IMRT fields. The calculated dose planes, with and without the proposed MLC transmission correction, were compared to measurements in solid water using a two-dimensional diode array. Results: It was observed that the integration of the MLC transmission correction into the BSS-EPID dose model improved agreement between modeled and measured dose planes. In particular, the MLC correction produced higher pass rates for almost all Head and Neck fields tested, yielding an average pass rate of 99.8% for 2%/2 mm criteria. A two-sample independentt-test and fisher F-test were used to show that the MLC transmission correction resulted in a statistically significant reduction in the mean and the standard deviation of the gamma values, respectively, to give a more accurate and consistent dose-to-water conversion. Conclusions: The frame-by-frame MLC transmission response correction was shown to improve the accuracy and reduce the variability of the BSS-EPID dose-to-water conversion model. The correction may be applied as a preprocessing step in any pretreatment portal dosimetry calculation and has been shown to be beneficial for highly modulated IMRT fields.

  4. Gi-coupled receptors mediate phosphorylation of CPI-17 and MLC20 via preferential activation of the PI3K/ILK pathway

    PubMed Central

    Huang, Jiean; Mahavadi, Sunila; Sriwai, Wimolpak; Hu, Wenhui; Murthy, Karnam S.

    2006-01-01

    Sustained smooth-muscle contraction or its experimental counterpart, Ca2+ sensitization, by Gq/13-coupled receptor agonists is mediated via RhoA-dependent inhibition of MLC (myosin light chain) phosphatase and MLC20 (20 kDa regulatory light chain of myosin II) phosphorylation by a Ca2+-independent MLCK (MLC kinase). The present study identified the corresponding pathways initiated by Gi-coupled receptors. Somatostatin acting via Gi1-coupled sstr3 receptor, DPDPE ([D-Pen2,D-Pen5]enkephalin; where Pen is penicillamine) acting via Gi2-coupled δ-opioid receptors, and cyclopentyl adenosine acting via Gi3-coupled adenosine A1 receptors preferentially activated PI3K (phosphoinositide 3-kinase) and ILK (integrin-linked kinase), whereas ACh (acetylcholine) acting via Gi3-coupled M2 receptors preferentially activated PI3K, Cdc42 (cell division cycle 42)/Rac1, PAK1 (p21-activated kinase 1) and p38 MAPK (mitogen-activated protein kinase). Only agonists that activated ILK induced sustained CPI-17 (protein kinase C potentiated inhibitor 17 kDa protein) phosphorylation at Thr38, MLC20 phosphorylation at Ser19, and contraction, consistent with recent evidence that ILK can act as a Ca2+-independent MLCK capable of phosphorylating the MLC phosphatase inhibitor, CPI-17, at Thr38. ILK activity, and CPI-17 and MLC20 phosphorylation were inhibited by LY294002 and in muscle cells expressing ILK(R211A) or treated with siRNA (small interfering RNA) for ILK. ACh acting via M2 receptors activated ILK, and induced CPI-17 and MLC20 phosphorylation and muscle contraction, but only after inhibition of p38 MAPK; all these responses were inhibited in cells expressing ILK(R211A). Conversely, ACh activated PAK1, a step upstream of p38 MAPK, whereas the three other agonists did so only in cells transfected with ILK(R211A) or siRNA for ILK. The results demonstrate reciprocal inhibition between two pathways downstream of PI3K, with ILK inhibiting PAK1, and p38 MAPK inhibiting ILK. Sustained contraction via Gi-coupled receptors is dependent on CPI-17 and MLC20 phosphorylation by ILK. PMID:16472257

  5. SU-E-T-128: Dosimetric Evaluation of MLC Modeling in Pinnacle V9.2 for Varian TrueBeam STx

    SciTech Connect

    Otageri, P; Grant, E; Maricle, S; Mathews, B

    2014-06-01

    Purpose: To evaluate the effects of MLC modeling after commissioning the Varian TrueBeam LINAC in Pinnacle version 9.2. Methods: Stepand-shoot IMRT QAs were investigated when we observed our measured absolute dose results using ion chamber (Capintec PR-05P) were uncharacteristically low; about 4–5% compared to doses calculated by Pinnacle{sup 3} (Phillips, Madison, WI). This problem was predominant for large and highly modulated head and neck (HN) treatments. Intuitively we knew this had to be related to shortcomings in the MLC modeling in Pinnacle. Using film QA we were able to iteratively adjust the MLC parameters. We confirmed results by re-testing five failed IMRT QA patients; and ion chamber measurements were verified in Quasar anthropomorphic phantom. Results: After commissioning the LINAC in Pinnacle version 9.2, the MLC transmission for 6X, 10X and 15X were 2.0%, 1.7% and 2.0%, respectively, and additional Interleaf leakage for all three energies was 0.5%. These parameters were obtained from profiles scanned with an Edge detector (Sun Nuclear, Melbourne, FL) during machine commissioning. A Verification testing with radiographic EDR2 film (Kodak, Rochester, NY) measurement was performed by creating a closed MLC leaf pattern and analyzing using RIT software (RIT, Colorado Springs, CO). This reduced MLC transmission for 6X, 10X and 15X to 0.7%, 0.9% and 0.9%, respectively; while increasing additional Interleaf leakage for all three energies to 1.0%. Conclusion: Radiographic film measurements were used to correct MLC transmission values for step and shoot IMRT fields used in Pinnacle version 9.2. After adjusting the MLC parameters to correlate with the film QA, there was still very good agreement between the Pinnacle model and commissioning data. Using the same QA methodology, we were also able to improve the beam models for the Varian C-series linacs, Novalis-Tx, and TrueBeam M-120 linacs.

  6. 76 FR 2193 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... Correspondence Exam Practitioner Engagement AGENCY: Internal Revenue Service (IRS) Treasury. ACTION: Notice of... Correspondence Exam Practitioner Engagement will be conducted. The Taxpayer Advocacy Panel is soliciting public... Advocacy Panel Small Business/Self Employed Correspondence Exam Practitioner Engagement will be...

  7. Asymmetric Programming: A Highly Reliable Metadata Allocation Strategy for MLC NAND Flash Memory-Based Sensor Systems

    PubMed Central

    Huang, Min; Liu, Zhaoqing; Qiao, Liyan

    2014-01-01

    While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it's critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB) pages which are more reliable than least significant bit (LSB) pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme. PMID:25310473

  8. Asymmetric programming: a highly reliable metadata allocation strategy for MLC NAND flash memory-based sensor systems.

    PubMed

    Huang, Min; Liu, Zhaoqing; Qiao, Liyan

    2014-01-01

    While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it's critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB) pages which are more reliable than least significant bit (LSB) pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme. PMID:25310473

  9. Effect of MLC tracking latency on conformal volumetric modulated arc therapy (VMAT) plans in 4D stereotactic lung treatment

    PubMed Central

    Bedford, James L.; Fast, Martin F.; Nill, Simeon; McDonald, Fiona M.A.; Ahmed, Merina; Hansen, Vibeke N.; Oelfke, Uwe

    2015-01-01

    Background and purpose The latency of a multileaf collimator (MLC) tracking system used to overcome respiratory motion causes misalignment of the treatment beam with respect to the gross tumour volume, which may result in reduced target coverage. This study investigates the magnitude of this effect. Material and methods Simulated superior–inferior breathing motion was used to construct histograms of isocentre offset with respect to the gross tumour volume (GTV) for a variety of tracking latencies. Dose distributions for conformal volumetric modulated arc therapy (VMAT) arcs were then calculated at a range of offsets and summed according to these displacement histograms. The results were verified by delivering the plans to a Delta4 phantom on a motion platform. Results In the absence of an internal target margin, a tracking latency of 150 ms reduces the GTV D95% by approximately 2%. With a margin of 2 mm, the same drop in dose occurs for a tracking latency of 450 ms. Lung V13Gy is unaffected by a range of latencies. These results are supported by the phantom measurements. Conclusions Assuming that internal motion can be modelled by a rigid translation of the patient, MLC tracking of conformal VMAT can be effectively accomplished in the absence of an internal target margin for substantial breathing motion (4 s period and 20 mm peak–peak amplitude) so long as the system latency is less than 150 ms. PMID:26277856

  10. State High School Exit Exams: Trends in Test Programs, Alternate Pathways, and Pass Rates

    ERIC Educational Resources Information Center

    Zhang, Ying

    2009-01-01

    The report draws from Center on Education Policy's eight-year study of high school exit exams to identify long-term trends in state policies and student performance. It highlights a growing trend among states to establish alternate pathways to graduation for students who are struggling to pass exit exams. The report also analyzes exit exam pass…

  11. Multiple-Choice and Short-Answer Exam Performance in a College Classroom

    ERIC Educational Resources Information Center

    Funk, Steven C.; Dickson, K. Laurie

    2011-01-01

    The authors experimentally investigated the effects of multiple-choice and short-answer format exam items on exam performance in a college classroom. They randomly assigned 50 students to take a 10-item short-answer pretest or posttest on two 50-item multiple-choice exams in an introduction to personality course. Students performed significantly…

  12. A Process of Students and Their Instructor Developing a Final Closed-Book Mathematics Exam

    ERIC Educational Resources Information Center

    Rapke, Tina

    2016-01-01

    This article describes a study, from a Canadian technical institute's upgrading mathematics course, where students played a role in developing the final closed-book exam that they sat. The study involved a process where students developed practice exams and solutions keys, students sat each other's practice exams, students evaluated classmates'…

  13. International Students' First Encounters with Exams in the UK: Superficially Similar but Deeply Different

    ERIC Educational Resources Information Center

    Pilcher, Nick; Smith, Karen; Riley, Jackie

    2013-01-01

    Although end of course exams remain a key mode of assessment in higher education, little research has focused on international students' experiences of exams. There seems to be a tacit assumption in most literature that exam preparation and strategies are universal, although differences in other areas of learning exist. As an exemplar,…

  14. An Exploration into Improving Examinees' Acceptance of Participation in an Online Exam

    ERIC Educational Resources Information Center

    Liu, I-Fan; Chen, Ruey-Shin; Lu, Hao-Chun

    2015-01-01

    With the rapid development of the Internet and information technology, the issues related to online exams have become the concern of an increasing number of researchers. At present, the biggest challenges for the integration of web communication technology into online exams are the ability to detect cheating behaviors during the exam, and the…

  15. Customized versus Standardized Exams for Learning Outcomes Assessment in an Undergraduate Business Program

    ERIC Educational Resources Information Center

    Phelps, Amy L.; Spangler, William E.

    2013-01-01

    A standardized exam for program-level assessment can take the form of 1) a customized exam developed in-house by faculty and linked explicitly to program-level learning goals; or 2) a standardized exam developed externally by assessment experts and linked to a set of somewhat broader and more generalizable learning goals. This article discusses…

  16. The Impact of High School Exit Exams on ESL Learners in British Columbia

    ERIC Educational Resources Information Center

    Odo, Dennis Murphy

    2012-01-01

    This essay explores the validity of including ELL students in British Columbia provincial high school exit exams. Data and a sample exam from the BC Ministry of education are used to scrutinize the practice of using BC provincial exams for high school exit decisions regarding ELLs. A comparison of failure rates of ELLs and mainstream students…

  17. Building the ACS Exams Anchoring Concept Content Map for Undergraduate Chemistry

    ERIC Educational Resources Information Center

    Murphy, Kristen; Holme, Thomas; Zenisky, April; Caruthers, Heather; Knaus, Karen

    2012-01-01

    The ability to coherently assess content knowledge throughout an entire undergraduate career represents a significant advantage for programmatic assessment strategies. Chemistry, as a discipline, has an unusual tool in this regard because of the nationally standardized exams from the ACS Exams Institute. These exams are norm-referenced and allow…

  18. Understanding and Reacting to the Anogenital Exam: Implications for Patient Preparation.

    ERIC Educational Resources Information Center

    Waibel-Duncan, Mary Katherine; Sanger, Maureen

    1999-01-01

    A study of 30 girls (ages 6-16) and their adult guardians found the majority of adults were inadequately prepared for their children's anogenital exams and reported that they receive no exam information prior to the clinic visit. Most children knew little about the exam's sensory or procedural aspects. (Author/CR)

  19. Effects of the Implementation of State-Wide Exit Exams on Students' Self-Regulated Learning

    ERIC Educational Resources Information Center

    Merki, Katharina Maag

    2011-01-01

    Whereas several studies investigated the effects of implementation of state-wide exit exams on student achievement, there is still little known about the impacts of the exams on students' self-regulated learning. This paper examines the question as to whether the implementation of state-wide high school exit exams is associated with a change in

  20. The Coordinators of Psychiatric Education (COPE) Residency In-Training Exam: A Preliminary Psychometric Assessment

    ERIC Educational Resources Information Center

    Montgomery, Gregory P. J.; Crockford, David N.; Hecker, Kent

    2010-01-01

    Objective: The Coordinators of Psychiatric Education (COPE) Residency In-Training Exam is a formative exam for Canadian psychiatric residents that was reconstructed using assessment best practices. An assessment of psychometric properties was subsequently performed on the exam to ensure preliminary validity and reliability. Methods: An exam…

  1. Faculty Forum--Introductory Psychology Student Performance: Weekly Quizzes Followed by a Cumulative Final Exam

    ERIC Educational Resources Information Center

    Landrum, R. Eric

    2007-01-01

    Students in an introductory psychology course took a quiz a week over each textbook chapter, followed by a cumulative final exam. Students missing a quiz in class could make up a quiz at any time during the semester, and answers to quiz items were available to students prior to the cumulative final exam. The cumulative final exam consisted of half…

  2. AL State Profile. Alabama: Alabama High School Graduation Exam (AHSGE), 3rd Edition

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper provides information about Alabama High School Graduation Exam, 3rd Edition, a comprehensive standards-based exam. The purpose of the exam is to: (1) Provide schools with student academic diagnostic information; (2) Determine prospective high school graduates' mastery of the state curriculum; (3) Increase alignment of local curriculum…

  3. Combined Online and In-Class Pretesting Improves Exam Performance in General Psychology

    ERIC Educational Resources Information Center

    Glass, Arnold Lewis; Brill, Gary; Ingate, Margaret

    2008-01-01

    This study examined the effect of distributed questioning on learning and retention in a college lecture course. A total of 48 question pairs were presented over four exams. The 16 question pairs associated with each of the three blocks of the course appeared on the block exams, and all 48 appeared on the final exam. The two questions in each pair…

  4. Supporting Student Learning: Improving Performance on Short-Essay Exams Using Realistic Practice Opportunities

    ERIC Educational Resources Information Center

    Dotson, Wesley H.; Sheldon, Jan B.; Sherman, James A.

    2010-01-01

    The present manuscript reports an attempt to support students in learning to apply knowledge from class to novel situations on course exams. Students took short-essay exams at the end of each unit. Students were offered two practice opportunities during each unit: answering practice questions and participating in a mock exam study session. On…

  5. Hispanic Student Performance on Advanced Placement Exams: A Multiyear, National Investigation

    ERIC Educational Resources Information Center

    Jara, Teresa Dianne

    2013-01-01

    Purpose: The purpose of this study was to analyze the Advanced Placement exams that Hispanic students complete and to compare their overall performance with the performance of White students from 2000 to 2012. A second purpose was to determine which Advanced Placement exams were the most difficult exams for Hispanic students and which Advanced

  6. An Exploration into Improving Examinees' Acceptance of Participation in an Online Exam

    ERIC Educational Resources Information Center

    Liu, I-Fan; Chen, Ruey-Shin; Lu, Hao-Chun

    2015-01-01

    With the rapid development of the Internet and information technology, the issues related to online exams have become the concern of an increasing number of researchers. At present, the biggest challenges for the integration of web communication technology into online exams are the ability to detect cheating behaviors during the exam, and the

  7. Like Climbing Jacob's Ladder: An Art-Based Exploration of the Comprehensive Exam Process

    ERIC Educational Resources Information Center

    Shields, Sara Scott

    2015-01-01

    The comprehensive exam process is a rite of passage in the scholarly world, and as such the movements of this process often feel like a guarded secret to graduate students. As a PhD candidate, I left the comprehensive exam process feeling both initiated and inundated. This article is an attempt to uncover the secret that is the comprehensive exam

  8. Hispanic Student Performance on Advanced Placement Exams: A Multiyear, National Investigation

    ERIC Educational Resources Information Center

    Jara, Teresa Dianne

    2013-01-01

    Purpose: The purpose of this study was to analyze the Advanced Placement exams that Hispanic students complete and to compare their overall performance with the performance of White students from 2000 to 2012. A second purpose was to determine which Advanced Placement exams were the most difficult exams for Hispanic students and which Advanced…

  9. Uncovering an Existential Barrier to Breast Self-exam Behavior

    PubMed Central

    Goldenberg, Jamie L.; Arndt, Jamie; Hart, Joshua; Routledge, Clay

    2008-01-01

    The present research applies an analysis derived from terror management theory to the health domain of breast examination, and in doing so uncovers previously unrecognized factors that may contribute to women’s reluctance to perform breast self-examinations (BSEs). In Study 1, when concerns about mortality were primed, reminders of human beings’ physical nature (i.e., creatureliness) reduced intentions to conduct BSEs compared to reminders of humans’ uniqueness. In Study 2, women conducted shorter exams on a breast model (an experience found to increase death-thought accessibility) when creatureliness was primed compared to a uniqueness and no essay condition. In Study 3, after a creatureliness prime, women performed shorter BSEs when a placebo did not provide an alternative explanation for their discomfort compared to when it did. Advances for theory and breast self-exam promotion are discussed. PMID:19255593

  10. Immune responses to final exams in healthy and asthmatic adolescents.

    PubMed

    Kang, D H; Coe, C L; McCarthy, D O; Ershler, W B

    1997-01-01

    Immune responses to an academic stressor were examined in healthy and asthmatic adolescents with regard to their illness symptom reports. Eighty-seven high school students completed a health diary for 2 weeks and provided three blood samples during midsemester, final-exam, and postexam periods. During exam week, all students showed significant immunological alterations from baseline. Natural killer cell activity was significantly lower, whereas lymphocyte proliferation and neutrophil superoxide release were significantly higher. These immune changes tended to return toward baseline during the postexam period, but the enhanced neutrophil reactivity continued to rise. Overall, immunological responses were similar between asthmatic subjects and controls. Appropriate medical management may have accounted for this similarity. However, subtle group differences in the postexam recovery pattern and a continuous activation of inflammatory cell function following a stressor may warrant further investigation. PMID:9024419

  11. Reworking Exams To Teach Chemistry Content and Reinforce Student Learning

    NASA Astrophysics Data System (ADS)

    Risley, John M.

    2007-09-01

    One meaningful approach to demonstrate to students the value of reworking exams is to offer an incentive to do so. This paper describes the strategy and effects of offering partial credit to students who rework answers originally answered incorrectly on an exam. This has proved largely successful for the last 10 years in several classes at the collegiate level. In the grading scheme used, the average percentage of the regrade on the final course grade is approximately 2 3%. While the regrade makes little difference in the final course grade for the majority of students, students are very appreciative of the opportunity afforded them, and this often changes their perspective of the class and the morale to a more positive attitude. Teachers in high school and in other disciplines may benefit from this approach.

  12. Correlates of Performance Anxiety in Practical Music Exams

    ERIC Educational Resources Information Center

    Rae, Gordon; McCambridge, Karen

    2004-01-01

    A sample of 120 young musicians (36 males and 84 females) aged between 15 and 18 years (M = 16.5, SD = 0.97) were administered the EPQ-R short scale and a revised PAI-R, a self-report measure of performance anxiety in practical music exams. Principal components analysis indicated that the PAI-R scores were best represented by a single component…

  13. Can formative quizzes predict or improve summative exam performance?*

    PubMed Central

    Zhang, Niu; Henderson, Charles N.R.

    2015-01-01

    Objective Despite wide use, the value of formative exams remains unclear. We evaluated the possible benefits of formative assessments in a physical examination course at our chiropractic college. Methods Three hypotheses were examined: (1) Receiving formative quizzes (FQs) will increase summative exam (SX) scores, (2) writing FQ questions will further increase SE scores, and (3) FQs can predict SX scores. Hypotheses were tested across three separate iterations of the class. Results The SX scores for the control group (Class 3) were significantly less than those of Classes 1 and 2, but writing quiz questions and taking FQs (Class 1) did not produce significantly higher SX scores than only taking FQs (Class 2). The FQ scores were significant predictors of SX scores, accounting for 52% of the SX score. Sex, age, academic degrees, and ethnicity were not significant copredictors. Conclusion Our results support the assertion that FQs can improve written SX performance, but students producing quiz questions didn't further increase SX scores. We concluded that nonthreatening FQs may be used to enhance student learning and suggest that they also may serve to identify students who, without additional remediation, will perform poorly on subsequent summative written exams. PMID:25517737

  14. Quantitative growth measurement of lesions in hepatic interval CT exams

    NASA Astrophysics Data System (ADS)

    Sarkar, Saradwata; Narayanan, Ramkrishnan; Park, Hyunjin; Ma, Bing; Bland, Peyton H.; Meyer, Charles R.

    2008-03-01

    Standard clinical radiological techniques for determining lesion volume changes in interval exams are, as far as we know, quantitatively non-descriptive or approximate at best. We investigate two new registration based methods that help sketch an improved quantitative picture of lesion volume changes in hepatic interval CT exams. The first method, Jacobian Integration, employs a constrained Thin Plate Spline warp to compute the deformation of the lesion of interest over the intervals. The resulting jacobian map of the deformation is integrated to yield the net lesion volume change. The technique is fast, accurate and requires no segmentation, but is sensitive to misregistration. The second scheme uses a Weighted Gray Value Difference image of two registered interval exams to estimate the change in lesion volume. A linear weighting and trimming curve is used to accurately account for the contribution of partial voxels. This technique is insensitive to slight misregistration and useful in analyzing simple lesions with uniform contrast or lesions with insufficient mutual information to allow the computation of an accurate warp. The methods are tested on both synthetic and in vivo liver lesions and results are evaluated against estimates obtained through careful manual segmentation of the lesions. Our findings so far have given us reason to believe that the estimators are reliable. Further experiments on numerous in vivo lesions will probably establish the improved efficacy of these methods in supporting earlier detection of new disease or conversion from stable to progressive disease in comparison to existing clinical estimation techniques.

  15. Interpretation of Biosphere Reserves.

    ERIC Educational Resources Information Center

    Merriman, Tim

    1994-01-01

    Introduces the Man and the Biosphere Programme (MAB) to monitor the 193 biogeographical provinces of the Earth and the creation of biosphere reserves. Highlights the need for interpreters to become familiar or involved with MAB program activities. (LZ)

  16. MLC Libraries--A School Library's Journey with Students, Staff and Web 2.0 Technologies: Blogs, Wikis and E-Books--Where Are We Going Next?

    ERIC Educational Resources Information Center

    Viner, Jane; Lucas, Amanda; Ricchini, Tracey; Ri, Regina

    2010-01-01

    This workshop paper explores the Web 2.0 journey of the MLC Libraries' teacher-librarians, librarian, library and audio visual technicians. Our journey was initially inspired by Will Richardson and supported by the School Library Association of Victoria (SLAV) Web 2.0 professional development program. The 12 week technological skills program "23…

  17. A Multistage Longitudinal Comparative (MLC) Design Stage II: Evaluation of the Changing Lives Program (CLP)--The Possible Selves Questionnaire-Qualitative Extensions (PSQ-QE)

    ERIC Educational Resources Information Center

    Kortsch, Gabrielle; Kurtines, William M.; Montgomery, Marilyn J.

    2008-01-01

    The study reported in this paper, a Multistage Longitudinal Comparative (MLC) Design Stage II evaluation conducted as a planned preliminary efficacy evaluation (psychometric evaluation of measures, short-term controlled outcome studies, etc.) of the Changing Lives Program (CLP), provided evidence for the reliability and validity of qualitative…

  18. TH-C-12A-06: Feasibility of a MLC-Based Inversely Optimized Multi-Field Grid Therapy Technique

    SciTech Connect

    Jin, J; Zhao, B; Huang, Y; Kim, J; Qin, Y; Wen, N; Ryu, S; Chetty, I

    2014-06-15

    Purpose: Grid therapy (GT), which generates highly spatially modulated dose distributions, can deliver single- or hypo-fractionated radiotherapy for large tumors without causing significant toxicities. GT may be applied in combination with immunotherapy, in light of recent preclinical data of synergetic interaction between radiotherapy and immunotherapy. However, conventional GT uses only one field, which does not have the advantage of multi-fields in 3D conformal-RT or IMRT. We have proposed a novel MLC-based, inverse-planned multi-field 3D GT technique. This study aims to test its deliverability and dosimetric accuracy. Methods: A lattice of small spheres was created as the boost volume within a large target. A simultaneous boost IMRT plan with 8-Gy to the target and 20-Gy to the boost volume was generated in the Eclipse treatment planning system (AAA v10) with a HD120 MLC. Nine beams were used, and the gantry and couch angles were selected so that the spheres were perfectly aligned in every beams eye view. The plan was mapped to a phantom with dose scaled. EBT3 films were calibrated and used to measure the delivered dose. Results: The IMRT plan generated a highly spatially modulated dose distribution in the target. D95%, D50%, D5% for the spheres and the targets in Gy were 18.5, 20.0, 21.4 and 7.9, 9.8, 16.1, respectively. D50% for a 1cm ring 1cm outside the target was 2.9-Gy. Film dosimetry showed good agreement between calculated and delivered dose, with an overall gamma passing rate of 99.6% (3%/1mm). The point dose differences for different spheres varied from 1–6%. Conclusion: We have demonstrated the deliverability and dose calculation accuracy of the MLC-based inversely optimized multi-field GT technique, which achieved a brachytherapy-like dose distribution. Single-fraction high dose can be delivered to the spheres in a large target with minimal dose to the surrounding normal tissue.

  19. Potential of discrete Gaussian edge feathering method for improving abutment dosimetry in eMLC-delivered segmented-field electron conformal therapy

    SciTech Connect

    Eley, John G.; Hogstrom, Kenneth R.; Matthews, Kenneth L.; Parker, Brent C.; Price, Michael J.

    2011-12-15

    Purpose: The purpose of this work was to investigate the potential of discrete Gaussian edge feathering of the higher energy electron fields for improving abutment dosimetry in the planning volume when using an electron multileaf collimator (eMLC) to deliver segmented-field electron conformal therapy (ECT). Methods: A discrete (five-step) Gaussian edge spread function was used to match dose penumbras of differing beam energies (6-20 MeV) at a specified depth in a water phantom. Software was developed to define the leaf eMLC positions of an eMLC that most closely fit each electron field shape. The effect of 1D edge feathering of the higher energy field on dose homogeneity was computed and measured for segmented-field ECT treatment plans for three 2D PTVs in a water phantom, i.e., depth from the water surface to the distal PTV surface varied as a function of the x-axis (parallel to leaf motion) and remained constant along the y-axis (perpendicular to leaf motion). Additionally, the effect of 2D edge feathering was computed and measured for one radially symmetric, 3D PTV in a water phantom, i.e., depth from the water surface to the distal PTV surface varied as a function of both axes. For the 3D PTV, the feathering scheme was evaluated for 0.1-1.0-cm leaf widths. Dose calculations were performed using the pencil beam dose algorithm in the Pinnacle{sup 3} treatment planning system. Dose verification measurements were made using a prototype eMLC (1-cm leaf width). Results: 1D discrete Gaussian edge feathering reduced the standard deviation of dose in the 2D PTVs by 34, 34, and 39%. In the 3D PTV, the broad leaf width (1 cm) of the eMLC hindered the 2D application of the feathering solution to the 3D PTV, and the standard deviation of dose increased by 10%. However, 2D discrete Gaussian edge feathering with simulated eMLC leaf widths of 0.1-0.5 cm reduced the standard deviation of dose in the 3D PTV by 33-28%, respectively. Conclusions: A five-step discrete Gaussian edge spread function applied in 2D improves the abutment dosimetry but requires an eMLC leaf resolution better than 1 cm.

  20. Pennogenin Tetraglycoside Induces Rat Myometrial Contraction and MLC20 Phosphorylation via PLC-IP3 and RhoA/Rho Kinase Signaling Pathways

    PubMed Central

    Liu, Xiaolan; Kang, Liping; Cong, Yue; Shan, Yajun; Zhao, Zhenhu; Ma, Baiping; Cong, Yuwen

    2012-01-01

    Background Total steroidal saponins extracted from the rhizome of Paris polyphylla Sm. var. yunnanensis (TSSPs) have been widely used in China for the treatment of abnormal uterine bleeding. We previously studied the main active constituents of TSSPs and their structure-activity relationships with respect to rat myometrial contractions. Tg (pennogenin tetraglycoside) was identified as one of the active ingredients in TSSPs able to induce rat myometrial contractions. However, the mechanisms underlying the pharmacological actions on uterine activity have not been described clearly. Methods Here Tg was screened for effects on contractile activity in isolated uterine strips from estrogen-primed rats and on MLC20 phosphorylation and related signaling pathways in cultured rat myometrial cells as determined by Western blot. Intracellular calcium ([Ca2+]i) was monitored under a confocal microscope using Fluo-4 AM-loaded myometrial cells. Results Tg dose-dependently stimulated rat myometrial contractions as well as MLC20 phosphorylation in vitro, which could be completely suppressed by an inhibitor of myosin light chain kinase (MLCK). Use of Ca2+ channel blockers and kinase inhibitors demonstrated that Tg-induced myometrial contractions are mediated by activation of the phospholipase C (PLC)-inositol triphosphate (IP3) signaling pathway, resulting in increased MLC20 phosphorylation. Furthermore, Y27632, a specific inhibitor of Rho kinase (ROK), notably suppressed Tg-stimulated myometrial contractions and decreased MLC20 phosphorylation. Conclusions These data provide evidence that rat myometrial contractility induced by Tg results from enhanced MLC20 phosphorylation, while both PLC-IP3 and RhoA/ROK signaling pathways mediate the process. These mechanisms may be responsible for the therapeutic effects of TSSPs on abnormal uterine bleeding. PMID:23251567

  1. SU-E-J-109: Testing the KV Imaging Center Congruence with Radiation Isocenter of Small MLC and SRS Cone Field On Two Machines

    SciTech Connect

    Fu,; Chen, Y; Yu, Y; Liu, H

    2014-06-01

    Purpose: Orthogonal kV image pairs are used for target localization when fiducial markers are implanted. CBCT is used to verify cone SRS setup. Therefore it is necessary to evaluate the isocenter congruence between radiation fields and kV imaging center. This study used a simple method to evaluate the isocenter congruence, and compared the results for MLC and cone fields on two different Linacs. Methods: Varian OBI block was attached on the couch. It has a central 1mm BB with markers on three surfaces to align with laser. KV and MV images were taken at four cardinal angles. A 3x3cm2 MLC field and a 20mm cone field were irradiated respectively. On each kV image, the distance from BB center to the kV graticule center were measured. On the MV image of MLC field, the center of radiation field was determined manually, while for cone field, the Varian AM maintenance software was used to analyze the distance between BB and radiation field. The subtraction of the two distances gives the discrepancy between kV and radiation centers. Each procedure was repeated on five days at Trilogy and TrueBeam respectively. Results: The maximum discrepancy was found in the longitudinal direction at 180° gantry angel. It was 1.5±0.1mm for Trilogy and 0.6±0.1mm for TrueBeam. For Trilogy, although radiation center wobbled only 0.7mm and image center wobbled 0.8mm, they wobbled to the opposite direction. KV Pair using gantry 180° should be avoided in this case. Cone vs. kV isocenter has less discrepancy than MLC for Trilogy. Conclusion: Radiation isocenter of MLC and cone field is different, so is between Trilogy and TrueBeam. The method is simple and reproducible to check kV and radiation isocenter congruence.

  2. The use of intensity-modulated radiation therapy photon beams for improving the dose uniformity of electron beams shaped with MLC

    SciTech Connect

    Mosalaei, Homeira; Karnas, Scott; Shah, Sheel; Van Doodewaard, Sharon; Foster, Tim; Chen, Jeff

    2012-04-01

    Electrons are ideal for treating shallow tumors and sparing adjacent normal tissue. Conventionally, electron beams are collimated by cut-outs that are time-consuming to make and difficult to adapt to tumor shape throughout the course of treatment. We propose that electron cut-outs can be replaced using photon multileaf collimator (MLC). Two major problems of this approach are that the scattering of electrons causes penumbra widening because of a large air gap, and available commercial treatment planning systems (TPSs) do not support MLC-collimated electron beams. In this study, these difficulties were overcome by (1) modeling electron beams collimated by photon MLC for a commercial TPS, and (2) developing a technique to reduce electron beam penumbra by adding low-energy intensity-modulated radiation therapy (IMRT) photons (4 MV). We used blocks to simulate MLC shielding in the TPS. Inverse planning was used to optimize boost photon beams. This technique was applied to a parotid and a central nervous system (CNS) clinical case. Combined photon and electron plans were compared with conventional plans and verified using ion chamber, film, and a 2D diode array. Our studies showed that the beam penumbra for mixed beams with 90 cm source to surface distance (SSD) is comparable with electron applicators and cut-outs at 100 cm SSD. Our mixed-beam technique yielded more uniform dose to the planning target volume and lower doses to various organs at risk for both parotid and CNS clinical cases. The plans were verified with measurements, with more than 95% points passing the gamma criteria of 5% in dose difference and 5 mm for distance to agreement. In conclusion, the study has demonstrated the feasibility and potential advantage of using photon MLC to collimate electron beams with boost photon IMRT fields.

  3. Investigating the Variables in a Mock Exam Study Session Designed to Improve Student Exam Performance in an Undergraduate Behavior Modification and Therapy Course

    ERIC Educational Resources Information Center

    Dotson, Wesley H.

    2010-01-01

    The purpose of the present study was to identify components of an optional mock exam review session (e.g. requiring students to write answers, providing students grading keys for questions) responsible for improvements in student performance on application-based short-essay exams in an undergraduate behavior modification course. Both…

  4. Development of the Exams Data Analysis Spreadsheet as a Tool to Help Instructors Conduct Customizable Analyses of Student ACS Exam Data

    ERIC Educational Resources Information Center

    Brandriet, Alexandra; Holme, Thomas

    2015-01-01

    The American Chemical Society Examinations Institute (ACS-EI) has recently developed the Exams Data Analysis Spread (EDAS) as a tool to help instructors conduct customizable analyses of their student data from ACS exams. The EDAS calculations allow instructors to analyze their students' performances both at the total score and individual item

  5. Development of the Exams Data Analysis Spreadsheet as a Tool to Help Instructors Conduct Customizable Analyses of Student ACS Exam Data

    ERIC Educational Resources Information Center

    Brandriet, Alexandra; Holme, Thomas

    2015-01-01

    The American Chemical Society Examinations Institute (ACS-EI) has recently developed the Exams Data Analysis Spread (EDAS) as a tool to help instructors conduct customizable analyses of their student data from ACS exams. The EDAS calculations allow instructors to analyze their students' performances both at the total score and individual item…

  6. Investigation into the need for ingesting foreign imaging exams into local systems and evaluation of the design challenges of Foreign Exam Management (FEM)

    NASA Astrophysics Data System (ADS)

    Milovanovic, Lazar; Agrawal, Arun; Bak, Peter; Bender, Duane; Koff, David

    2015-03-01

    The deployment of regional and national Electronic Health Record solutions has been a focus of many countries throughout the past decade. Most of these deployments have taken the approach of "sharing" imaging exams via portals and web-based viewers. The motivation of portal/web-based access is driven by a) the perception that review of imaging exams via portal methods is satisfactory to all users and b) the perceived complexity of ingesting foreign exams into local systems. This research project set out to objectively evaluate who really needs foreign exams within their local systems, what those systems might be and how often this is required. Working on the belief that Foreign Exam Management (FEM) is required to support clinical workflow, the project implemented a FEM capability within an XDSI. b domain to identify the design challenges and nuances associated with FEM.

  7. SU-E-T-475: An Accurate Linear Model of Tomotherapy MLC-Detector System for Patient Specific Delivery QA

    SciTech Connect

    Chen, Y; Mo, X; Chen, M; Olivera, G; Parnell, D; Key, S; Lu, W; Reeher, M; Galmarini, D

    2014-06-01

    Purpose: An accurate leaf fluence model can be used in applications such as patient specific delivery QA and in-vivo dosimetry for TomoTherapy systems. It is known that the total fluence is not a linear combination of individual leaf fluence due to leakage-transmission, tongue-and-groove, and source occlusion effect. Here we propose a method to model the nonlinear effects as linear terms thus making the MLC-detector system a linear system. Methods: A leaf pattern basis (LPB) consisting of no-leaf-open, single-leaf-open, double-leaf-open and triple-leaf-open patterns are chosen to represent linear and major nonlinear effects of leaf fluence as a linear system. An arbitrary leaf pattern can be expressed as (or decomposed to) a linear combination of the LPB either pulse by pulse or weighted by dwelling time. The exit detector responses to the LPB are obtained by processing returned detector signals resulting from the predefined leaf patterns for each jaw setting. Through forward transformation, detector signal can be predicted given a delivery plan. An equivalent leaf open time (LOT) sinogram containing output variation information can also be inversely calculated from the measured detector signals. Twelve patient plans were delivered in air. The equivalent LOT sinograms were compared with their planned sinograms. Results: The whole calibration process was done in 20 minutes. For two randomly generated leaf patterns, 98.5% of the active channels showed differences within 0.5% of the local maximum between the predicted and measured signals. Averaged over the twelve plans, 90% of LOT errors were within +/−10 ms. The LOT systematic error increases and shows an oscillating pattern when LOT is shorter than 50 ms. Conclusion: The LPB method models the MLC-detector response accurately, which improves patient specific delivery QA and in-vivo dosimetry for TomoTherapy systems. It is sensitive enough to detect systematic LOT errors as small as 10 ms.

  8. 46 CFR 71.50-3 - Drydock examination, internal structural examination, underwater survey, and alternate hull exam...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., underwater survey, and alternate hull exam intervals. 71.50-3 Section 71.50-3 Shipping COAST GUARD...-3 Drydock examination, internal structural examination, underwater survey, and alternate hull exam..., the vessel must undergo two alternate hull exams and two internal structural exams within any...

  9. 46 CFR 71.50-3 - Drydock examination, internal structural examination, underwater survey, and alternate hull exam...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., underwater survey, and alternate hull exam intervals. 71.50-3 Section 71.50-3 Shipping COAST GUARD...-3 Drydock examination, internal structural examination, underwater survey, and alternate hull exam..., the vessel must undergo two alternate hull exams and two internal structural exams within any...

  10. 46 CFR 71.50-3 - Drydock examination, internal structural examination, underwater survey, and alternate hull exam...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., underwater survey, and alternate hull exam intervals. 71.50-3 Section 71.50-3 Shipping COAST GUARD...-3 Drydock examination, internal structural examination, underwater survey, and alternate hull exam..., the vessel must undergo two alternate hull exams and two internal structural exams within any...

  11. 46 CFR 71.50-3 - Drydock examination, internal structural examination, underwater survey, and alternate hull exam...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., underwater survey, and alternate hull exam intervals. 71.50-3 Section 71.50-3 Shipping COAST GUARD...-3 Drydock examination, internal structural examination, underwater survey, and alternate hull exam..., the vessel must undergo two alternate hull exams and two internal structural exams within any...

  12. 46 CFR 71.50-3 - Drydock examination, internal structural examination, underwater survey, and alternate hull exam...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., underwater survey, and alternate hull exam intervals. 71.50-3 Section 71.50-3 Shipping COAST GUARD...-3 Drydock examination, internal structural examination, underwater survey, and alternate hull exam..., the vessel must undergo two alternate hull exams and two internal structural exams within any...

  13. Advanced Ultrasonic Diagnosis of Extremity Trauma: The Faster Exam

    NASA Technical Reports Server (NTRS)

    Dulchavsky, S. A.; Henry, S. E.; Moed, B. R.; Diebel, L. N.; Marshburn, T.; Hamilton, D. R.; Logan, J.; Kirkpatrick, A. W.; Williams, D. R.

    2002-01-01

    Ultrasound is of prO)len accuracy in abdominal and thoracic trauma and may be useful to diagnose extremity injury in situations where radiography is not available such as military and space applications. We prospectively evaluated the utility of extremity , ultrasound performed by trained, non-physician personnel in patients with extremity trauma, to simulate remote aerospace or military applications . Methods: Patients with extremity trauma were identified by history, physical examination, and radiographic studies. Ultrasound examination was performed bilaterally by nonphysician personnel with a portable ultrasound device using a 10-5 MHz linear probe, Images were video-recorded for later analysis against radiography by Fisher's exact test. The average time of examination was 4 minutes. Ultrasound accurately diagnosed extremity, injury in 94% of patients with no false positive exams; accuracy was greater in mid-shaft locations and least in the metacarpa/metatarsals. Soft tissue/tendon injury was readily visualized . Extremity ultrasound can be performed quickly and accurately by nonphysician personnel with excellent accuracy. Blinded verification of the utility of ultrasound in patients with extremity injury should be done to determine if Extremity and Respiratory evaluation should be added to the FAST examination (the FASTER exam) and verify the technique in remote locations such as military and aerospace applications.

  14. How chemistry students study for an exam: A phenomenographic analysis

    NASA Astrophysics Data System (ADS)

    Lowrey, Kirsten Andrea

    2002-08-01

    The purpose of this research was to understand the different ways that students in a second-semester general chemistry course studied for an exam. I conducted this research using a qualitative methodology based on phenomenography (Marton, Hounsell & Entwistle, 1997). I conducted interviews before and after the first exam in CHM 116. I analyzed these interviews to describe students' studying styles. I analyzed the data from four students and presented this data as case studies. I completed a cross-case analysis that included data from five additional students. My results describe three different studying styles that were found: visual, self-regulated, and quantitative. Each studying style included a description of the characteristics associated with students who use the style, including epistemological beliefs, specific study behaviors, and affective response to learning chemistry. My implications discuss the relationship between this study and learning styles research, as well as other phenomenographic research. Suggestions are made for how to adapt teaching methods to take into account the different studying styles.

  15. Opening up in the classroom: effects of expressive writing on graduate school entrance exam performance.

    PubMed

    Frattaroli, Joanne; Thomas, Michael; Lyubomirsky, Sonja

    2011-06-01

    Our study sought to determine whether experimental disclosure could improve exam performance and psychological health in students taking a graduate school entrance exam. Students preparing for the GRE, MCAT, LSAT, or PCAT were randomly assigned to write expressively about their upcoming exam or to a neutral writing condition. Participants completed measures of depressive symptoms and test anxiety before and after writing, and exam scores were collected. The experimental disclosure group had significantly higher test scores and significantly lower pre-exam depressive symptoms than the neutral writing group. Although benefits for depressive symptoms were found in expressive writers regardless of exam type, the advantage of expressive writing for test performance was only observed in students taking the MCAT or LSAT. PMID:21517162

  16. Developing, deploying, and analyzing exam wrappers in a large introductory physics class

    NASA Astrophysics Data System (ADS)

    Greco, Edwin

    2012-03-01

    In a typical semester, approximately 2000 students are registered into a calculus based introductory physics course at Georgia Tech. In each course, approximately 75 percent of a student's final grade is based on exam performance. Our goal was to encourage students into the feedback cycle of self-regulated learning by asking them to complete exam wrappers; post examination assignments that ask student to reflect on their study habits and errors made during an exam. We cluster students into groups based on how they partitioned their study time. We analyze exam and overall course performance for each group. In addition, we compare the performance of students who completed exam wrappers with those that did not. We find that exam wrappers are useful tool for both the instructor and student.

  17. 5 CFR 890.503 - Reserves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... law from other contingency reserves and the administrative reserve; (iii) Income from investment of the reserve; (iv) Its proportionate share of the income from investment of the administrative reserve; and (v) Any return of reserves of the plan. (2) Contingency reserve minimum balance. The...

  18. 26 CFR 27 - Reserved

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Reserved 27 PARTS 27-29 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX REGULATIONS UNDER THE TAX REFORM ACT OF 1986 PARTS 27-29...

  19. Washington: Hanford Nuclear Reservation

    Atmospheric Science Data Center

    2014-05-15

    ... (MISR) image pair shows "before and after" views of the area around the Hanford Nuclear Reservation near Richland, Washington. On June ... By the day after the accident, about 100,000 acres had burned, and the fire's spread forced the closure of highways and loss of homes. ...

  20. Want to Reduce Guessing and Cheating While Making Students Happier? Give More Exams!

    NASA Astrophysics Data System (ADS)

    Laverty, James T.; Bauer, Wolfgang; Kortemeyer, Gerd; Westfall, Gary

    2012-12-01

    It is almost universally agreed that more frequent formative assessment (homework, clicker questions, practice tests, etc.) leads to better student performance and generally better course evaluations. There is, however, only anecdotal evidence that the same would be true for more frequent summative assessment (exams). There maybe many arguments against giving more exams, including the general "pain" associated with examinations, as well as reduced teaching time, since classroom sessions are dedicated to exams rather than lecturing. We present evidence that increasing the number of exams in fact does lead to better learning success, less cheating and guessing on homework, and better student course evaluations.

  1. Assessment of the relationship between stress and temporomandibular joint disorder in female students before university entrance exam (Konkour exam)

    PubMed Central

    Mottaghi, Ahmad; Razavi, S. Mohammad; Pozveh, Elham Zamani; Jahangirmoghaddam, Milad

    2011-01-01

    Background: Temporomandibular joint is one of the most complicated joints of the body and plays an important role in the head and neck system. One of the factors affecting the temporomandibular joint and lead to temporomandibular disorder is anxiety with all the events causing it. The aim of this study was to determine a relationship between anxiety and temporomandibular disorders. Materials and Methods: In this prospective study, subjects were randomly selected. One hundred and thirty pre-university students in Isfahan were evaluated with Ketel's test of anxiety, exam stress test and temporomandibular disorder questionnaires. The evaluation was done in two stages 10 months and 1 month prior to the university entrance exam (Konkour), clinical assessments consisted of masticatory muscles and sternocleidomastoid muscle palpation, temporomandibular joint palpation for pain and noise and its movement, and mouth opening limitations. The Wilcoxon rank test and paired t-test were used to analyze the data and the P value under 0.05 was considered significant. Results: The level of anxiety and occurrence of temporomandibular disorders were increased between two stages and had the highest level in the second stage. There was a significant increase between two stages (P<0.001). Conclusion: The parallel increase of temporomandibular disorders and anxiety between the two stages can suggest a possible relationship between anxiety and temporomandibular disorders. Therefore, the effect of anxiety in triggering temporomandibular disorder symptoms is probable. PMID:23372600

  2. Structural and Electronic Transformations of Pt/C, Pd@Pt(1 ML)/C and Pd@Pt(2 ML)/C Cathode Catalysts in Polymer Electrolyte Fuel Cells during Potential-step Operating Processes Characterized by In-situ Time-resolved XAFS

    NASA Astrophysics Data System (ADS)

    Nagamatsu, Shin-ichi; Takao, Shinobu; Samjeské, Gabor; Nagasawa, Kensaku; Sekizawa, Oki; Kaneko, Takuma; Higashi, Kotaro; Uruga, Tomoya; Gayen, Sirshendu; Velaga, Srihari; Saniyal, Milan K.; Iwasawa, Yasuhiro

    2016-06-01

    The dynamic structural and electronic transformations of Pt/C, Pd@Pt(1 ML)/C, Pd@Pt(2 ML)/C cathode catalysts in polymer electrolyte fuel cells (PEFCs) during the potential-step operating processes between 0.4 and 1.4 VRHE (potential vs RHE) were characterized by in-situ (operando) time-resolved Pt LIII-edge quick-XAFS at 100 ms time-resolution. Potential-dependent surface structures and oxidation states of Pt, Pd@Pt(1 ML) and Pd@Pt(2 ML) nanoparticles on carbon at 0.4 and 1.4 VRHE were also analyzed by in-situ Pt LIII-edge and Pd K-edge quick-XAFS. The Pt, Pd@Pt(1 ML) and Pd@Pt(2 ML) nanoparticle surfaces were restructured and disordered at 1.4 VRHE, which were induced by strong Pt-O bonds as well as alloying effects. The rate constants for the changes of Pt valence, CN(Pt-Pt), CN(Pt-Pd) and CN(Pt-O) (CN: coordination number) in the potential-step operating processes were also determined and discussed in relation to the origin of oxygen reduction reaction (ORR) activities of the Pt/C, Pd@Pt(1 ML)/C and Pd@Pt(2 ML)/C cathode catalysts.

  3. Time-resolved dose distributions to moving targets during volumetric modulated arc therapy with and without dynamic MLC tracking

    PubMed Central

    Ravkilde, Thomas; Keall, Paul J.; Grau, Cai; Høyer, Morten; Poulsen, Per R.

    2013-01-01

    Purpose: The highly conformal doses delivered by volumetric modulated arc therapy (VMAT) may be compromised by intrafraction target motion. Although dynamic multileaf collimator (DMLC) tracking can mitigate the dosimetric impact of motion on the accumulated dose, residual errors still exist. The purpose of this study was to investigate the temporal evolution of dose errors throughout VMAT treatments delivered with and without DMLC tracking. Methods: Tracking experiments were performed on a linear accelerator connected to prototype DMLC tracking software. A three-axis motion stage reproduced representative clinical trajectories of four lung tumors and four prostates. For each trajectory, two VMAT treatment plans (low and high modulation) were delivered with and without DMLC tracking as well as to a static phantom for reference. Dose distributions were measured continuously at 72 Hz using a dosimeter with biplanar diode arrays. During tracking, the MLC leaves were continuously refitted to the 3D target position measured by an electromagnetic transponder at 30 Hz. The dosimetric errors caused in the 32 motion experiments were quantified by a time-resolved 3%/3 mmγ-test. The erroneously exposed areas in treatment beam's eye view (BEV) caused by inadequate real-time MLC adaptation were calculated and compared with the time-resolved γ failure rates. Results: The transientγ failure rate was on average 16.8% without tracking and 5.3% with tracking. The γ failure rate correlated well with the erroneously exposed areas in BEV (mean of Pearson r = 0.83, p < 0.001). For the final accumulated doses, the mean γ failure rate was 17.9% without tracking and 1.0% with tracking. With tracking the transient dose errors tended to cancel out resulting in the low mean γ failure rate for the accumulated doses. Conclusions: Time-resolved measurements allow pinpointing of transient errors in dose during VMAT delivery as well as monitoring of erroneous dose evolution in key target positions. The erroneously exposed area in BEV was shown to be a good indicator of errors in the dose distribution during treatment delivery. PMID:24320431

  4. A history of interpersonal trauma and the gynecological exam.

    PubMed

    Ackerson, Kelly

    2012-05-01

    Cervical cancer is preventable, in part, by routine Papanicolaou (Pap) testing, but some women avoid routine screening. African American women have the greatest mortality among all groups of women in the United States. Personal reasons have been found to contribute to screening avoidance behavior, such as a history of sexual abuse and intimate partner violence. Fifteen African American women with a trauma history participated in personal interviews. The Interaction Model of Client Behavior was employed for exploring the women's social influence, previous health care experience, cognitive appraisal, affective response, and motivation associated with routine Pap testing. Study findings suggest that providers need to assess and provide accurate information about Pap testing and cervical cancer to increase patients' knowledge. Personally reflecting on one's approach to conducting a woman's gynecologic exam (and how it is performed) might prevent triggering unwanted memories, making that visit a positive experience and facilitating repeat screening behavior. PMID:22068042

  5. The University Entrance Exam that Diversified and the Problem

    NASA Astrophysics Data System (ADS)

    Kondo, Osamu

    The percentage of students who go on to universities or junior colleges is over fifty percent which is more than half of high school students. However the nation's birthrate is in decline and the total number of university-age children shows a declining tendency. Hence we cannot expect an increase in the number of applicants in the future. On the other hand, the number of universities has been increasing year by year. The competition among universities to survive is very fierce. The diversification of entrance examination is a symbol of this competition. By diversifying entrance exams, universities aimed at the quality of excellent students in the beginning. However, they have changed their direction to pursue the quantity of students. As of Today the entrance examination is losing its original starting function which means most or all applicants can enter universities. It is time all of the universities return to its starting line.

  6. Melatonin Attenuates Aortic Endothelial Permeability and Arteriosclerosis in Streptozotocin-Induced Diabetic Rats: Possible Role of MLCK- and MLCP-Dependent MLC Phosphorylation.

    PubMed

    Tang, Song-tao; Su, Huan; Zhang, Qiu; Tang, Hai-qin; Wang, Chang-jiang; Zhou, Qing; Wei, Wei; Zhu, Hua-qing; Wang, Yuan

    2016-01-01

    The development of diabetic macrovascular complications is a multifactorial process, and melatonin may possess cardiovascular protective properties. This study was designed to evaluate whether melatonin attenuates arteriosclerosis and endothelial permeability by suppressing the myosin light-chain kinase (MLCK)/myosin light-chain phosphorylation (p-MLC) system via the mitogen-activated protein kinase (MAPK) signaling pathway or by suppressing the myosin phosphatase-targeting subunit phosphorylation (p-MYPT)/p-MLC system in diabetes mellitus (DM). Rats were randomly divided into 4 groups, including control, high-fat diet, DM, and DM + melatonin groups. Melatonin was administered (10 mg/kg/d) by gavage for 12 weeks. The DM significantly increased the serum fasting blood glucose and lipid levels, as well as insulin resistance and endothelial dysfunction, which were attenuated by melatonin therapy to various extents. Importantly, the aortic endothelial permeability was significantly increased in DM rats but was dramatically reversed following treatment with melatonin. Our findings further indicated that hyperglycemia and hyperlipidemia enhanced the expressions of MLCK, p-MYPT, and p-MLC, which were partly associated with decreased membrane type 1 expression, increased extracellular signal-regulated kinase (ERK) phosphorylation, and increased p38 expression. However, these changes in protein expression were also significantly reversed by melatonin. Thus, our results are the first to demonstrate that the endothelial hyperpermeability induced by DM is associated with increased expressions of MLCK, p-MYPT, and p-MLC, which can be attenuated by melatonin at least partly through the ERK/p38 signaling pathway. PMID:25944844

  7. Effects of tertiary MLC configuration on secondary neutron spectra from 18 MV x-ray beams for the Varian 21EX linear accelerator

    PubMed Central

    Howell, Rebecca M.; Kry, Stephen F.; Burgett, Eric; Followill, David; Hertel, Nolan E.

    2009-01-01

    The effect of the jaw configuration and the presence and configuration of the tertiary multileaf collimator (MLC) on the secondary neutron spectra for an 18 MV Varian 21EX linear accelerator (linac) is investigated in detail. The authors report the measured spectra for four collimator (jaw-and-MLC) configurations. These configurations represent the extreme settings of the jaws and MLC and should therefore describe the range of possible fluence and spectra that may be encountered during use of this linac. In addition to measurements, a Monte Carlo model was used to simulate the four collimator configurations and calculate the energy spectra and fluence at the same location as it was measured. The Monte Carlo model was also used to calculate the sources of neutron production in the linac head for each collimator configuration. They found that photoneutron production in the linac treatment head is dominated by the order in which the primary photon beam intercepts the high-Z material. The primary collimator, which has the highest position in the linac head (in a fixed location), is the largest source of secondary neutrons. Thereafter, the collimator configuration plays a role in where the neutrons originate. For instance, if the jaws are closed, they intercept the beam and contribute substantially to the secondary neutron production. Conversely, if the jaws are open, the MLC plays a larger role in neutron production (assuming, of course, that it intercepts the beam). They found that different collimator configurations make up to a factor of 2 difference in the ambient dose equivalent. PMID:19810476

  8. Monte Carlo model of the Elekta SLiplus accelerator: validation of a new MLC component module in BEAM for a 6 MV beam

    NASA Astrophysics Data System (ADS)

    Van de Walle, J.; Martens, C.; Reynaert, N.; Palmans, H.; Coghe, M.; DeNeve, W.; DeWagter, C.; Thierens, H.

    2003-02-01

    A new component module (CM), called MLCE, has been implemented in the BEAM program. The CM takes into account the particular 'tongue-and-groove' design of the Elekta multi-leaf collimator (MLC) and the air gap between the leaves. The model was validated by two series of measurements and simulations. The first benchmarking series focuses on the interleaf leakage and the intraleaf transmission. The measurement showed a total transmission through the MLC of 1.42% of the open field dose. Two Monte Carlo (MC) simulations were made, the first with the new CM MLCE (inclusive of air gap) and the second with the CM MLCQ (exclusive of air gap), which is available in the BEAM distribution. When the air gap between the leaves was determined by varying the parameters of the leaf geometry within tolerance limits on the technical drawing, the total measured transmission of 1.42% was well reproduced by the CM MLCE. In contrast, MC simulations with MLCQ showed that the transmission through the MLC calculated without the interleaf leakage is only 44% of the total transmitted radiation. The relevance of the detailed MLC modelling was demonstrated also by studying the 'adjacent' tongue-and-groove effect, where two adjacent (not opposing) leaves are complementary, opened or closed. The two complementary leaf settings were simulated both with the CM MLCE and MLCQ. A comparison with measurements was made. In regions covered by two or more leaves, the dose increased by 14% for two leaves and by 40% for more than two leaves when the interleaf leakage was included in the transmission. The tongue-and-groove effect was perfectly reproduced by the MLCE module.

  9. Correlation of the NBME Advanced Clinical Examination in EM and the National EM M4 exams

    PubMed Central

    Hiller, Katherine; Miller, Emily S.; Lawson, Luan; Wald, David; Beeson, Michael; Heitz, Corey; Morrissey, Thomas; House, Joseph; Poznanski, Stacey

    2015-01-01

    Introduction Since 2011 two online, validated exams for fourth-year emergency medicine (EM) students have been available (National EM M4 Exams). In 2013 the National Board of Medical Examiners offered the Advanced Clinical Examination in Emergency Medicine (EM-ACE). All of these exams are now in widespread use; however, there are no data on how they correlate. This study evaluated the correlation between the EM-ACE exam and the National EM M4 Exams. Methods From May 2013 to April 2014 the EM-ACE and one version of the EM M4 exam were administered sequentially to fourth-year EM students at five U.S. medical schools. Data collected included institution, gross and scaled scores and version of the EM M4 exam. We performed Pearson’s correlation and random effects linear regression. Results 303 students took the EM-ACE and versions 1 (V1) or 2 (V2) of the EM M4 exams (279 and 24, respectively). The mean percent correct for the exams were as follows: EM-ACE 74.8 (SD-8.83), V1 83.0 (SD-6.41), V2 78.5 (SD-7.70). Pearson’s correlation coefficient for the V1/EM-ACE was 0.51 (0.42 scaled) and for the V2/EM-ACE was 0.59 (0.41 scaled). The coefficient of determination for V1/EM-ACE was 0.72 and for V2/EM-ACE = 0.71 (0.86 and 0.49 for scaled scores). The R-squared values were 0.25 and 0.30 (0.18 and 0.13, scaled), respectively. There was significant cluster effect by institution. Conclusion There was moderate positive correlation of student scores on the EM-ACE exam and the National EM M4 Exams. PMID:25671023

  10. Changes in Student Attributions Due to the Implementation of Central Exit Exams

    ERIC Educational Resources Information Center

    Oerke, Britta; Maag Merki, Katharina; Holmeier, Monika; Jager, Daniela J.

    2011-01-01

    The central aim of standardized exit exams is to motivate students and teachers to work harder on critical subject matters and thus increase student achievement. However, the effects of the implementation of central exams on student motivation have not been analyzed in a longitudinal section until now. In the present study, the consequences of

  11. What Does a Student Know Who Earns a Top Score on the Advanced Placement Chemistry Exam?

    ERIC Educational Resources Information Center

    Claesgens, Jennifer; Daubenmire, Paul L.; Scalise, Kathleen M.; Balicki, Scott; Gochyyev, Perman; Stacy, Angelica M.

    2014-01-01

    This paper compares the performance of students at a high-performing U.S. public school (n = 64) on the advanced placement (AP) chemistry exam to their performance on the ChemQuery assessment system. The AP chemistry exam was chosen because, as the National Research Council acknowledges, it is the "perceived standard of excellence and school…

  12. Effects of Online Testing on Student Exam Performance and Test Anxiety

    ERIC Educational Resources Information Center

    Stowell, Jeffrey R.; Bennett, Dan

    2010-01-01

    Increased use of course management software to administer course exams online for face-to-face classes raises the question of how well test anxiety and other emotions generalize from the classroom to an online setting. We hypothesized that administering regular course exams in an online format would reduce test anxiety experienced at the time of…

  13. Student Grade Motivation as a Determinant of Performance on the Business Major Field ETS Exam

    ERIC Educational Resources Information Center

    Terry, Neil; Mills, LaVelle; Sollosy, Marc

    2008-01-01

    This paper examines the determinants of performance on the business major field achievement ETS exam with a focus on the impact of applying ETS exam scores to part of the capstone course grade as a performance incentive. The sample consists of 150 students at a midsized regional institution located in the Southwestern region of the United States.…

  14. Knowledge Assessment of Food Safety Managers in Utah and Its Implications on the Exam and Instruction

    ERIC Educational Resources Information Center

    Nummer, Brian A.; Guy, Stanley M.; Bentley, Joanne P. H.

    2010-01-01

    Food Safety Manager's Certification is offered through a state-local Extension partnership in Utah using an online course management system. Exams and course materials were created by an Extension Specialist at Utah State Univ. Extension Agents provide exam and curriculum facilitation in each county. This form of distance education enables access…

  15. A Study of the Technological, Instructional, and Motivational Factors Affecting PHR Certification Exam Outcomes

    ERIC Educational Resources Information Center

    Bonner, David M.

    2012-01-01

    Although previous studies have considered the factors affecting other certification exam outcomes, they have not examined those that are related to performance on the Professional in Human Resources (PHR) exam. In response to that need, this study specifically investigates technology and training factors that affect self-efficacy and self-set

  16. Verbal Final Exam in Introductory Biology Yields Gains in Student Content Knowledge and Longitudinal Performance

    ERIC Educational Resources Information Center

    Luckie, Douglas B.; Rivkin, Aaron M.; Aubry, Jacob R.; Marengo, Benjamin J.; Creech, Leah R.; Sweeder, Ryan D.

    2013-01-01

    We studied gains in student learning over eight semesters in which an introductory biology course curriculum was changed to include optional verbal final exams (VFs). Students could opt to demonstrate their mastery of course material via structured oral exams with the professor. In a quantitative assessment of cell biology content knowledge,

  17. Relationships between Self-Regulating Behaviors and Predictor Exam Scores for Senior Nursing Students

    ERIC Educational Resources Information Center

    Gillespie, Maria

    2012-01-01

    Low pass rates on the National Council Licensure Exam for Registered Nurses have directed nursing faculty to examine how to predict the readiness of the nursing student. Exit exam testing that predicts readiness has become one way to assess the nursing student's readiness. Nursing students at the research site's school of nursing are…

  18. Scholars Probe Diverse Effects of Exit Exams: State Graduation Tests Found to Hit Certain Groups Harder

    ERIC Educational Resources Information Center

    Viadero, Debra

    2009-01-01

    A study released last week suggesting that California's high school exit exams are affecting some student demographic groups more than others is the latest in a small spate of studies pointing to trade-offs from policies that require high school students to pass state tests to graduate. Twenty-six states have exit exams in place or will by 2012,…

  19. A Multi-Year Analysis of Asian Gender Differences on Advanced Placement Exams

    ERIC Educational Resources Information Center

    Moore, George; Slate, John R.

    2011-01-01

    The performance of Asian boys and girls on Advanced Placement (AP) exam overall scores across the United States for the past 14 years was analyzed. For each of the 14 years of data analyzed, Asian boys had statistically significant higher percentages of overall AP exam scores of 5 than did Asian girls. In addition, the gap between the mean…

  20. Training Metacognition in the Classroom: The Influence of Incentives and Feedback on Exam Predictions

    ERIC Educational Resources Information Center

    Miller, Tyler M.; Geraci, Lisa

    2011-01-01

    In two semester-long studies, we examined whether college students could improve their ability to accurately predict their own exam performance across multiple exams. We tested whether providing concrete feedback and incentives (i.e., extra credit) for accuracy would improve predictions by improving students' metacognition, or awareness of their…

  1. Exam High Schools and Academic Achievement: Evidence from New York City. NBER Working Paper No. 17286

    ERIC Educational Resources Information Center

    Dobbie, Will; Fryer, Roland G., Jr.

    2011-01-01

    Publicly funded exam schools educate many of the world's most talented students. These schools typically contain higher achieving peers, more rigorous instruction, and additional resources compared to regular public schools. This paper uses a sharp discontinuity in the admissions process at three prominent exam schools in New York City to provide…

  2. Training Children with Autism Spectrum Disorders to Be Compliant with a Physical Exam

    ERIC Educational Resources Information Center

    Cuvo, Anthony J.; Reagan, Amanda Law; Ackerlund, Julie; Huckfeldt, Rachel; Kelly, Cheri

    2010-01-01

    The purpose of this study was to train children with autism spectrum disorders to be compliant with a 10-component physical examination. After a physician assistant administered an exam pretest, noncompliance on steps of the exam were considered with respect to a skill deficit and escape from aversive stimuli. A package of training procedures was…

  3. Cheating on Multiple-Choice Exams: Monitoring, Assessment, and an Optional Assignment

    ERIC Educational Resources Information Center

    Nath, Leda; Lovaglia, Michael

    2009-01-01

    Academic dishonesty is unethical. Exam cheating is viewed as more serious than most other forms (Pincus and Schmelkin 2003). The authors review the general cheating problem, introduce a program to conservatively identify likely cheaters on multiple-choice exams, and offer a procedure for handling likely cheaters. Feedback from students who confess…

  4. Re-Examining Exit Exams: New Findings from the Education Longitudinal Study of 2002

    ERIC Educational Resources Information Center

    Shuster, Kate

    2012-01-01

    Using the nationally representative, cohort-based data of the Education Longitudinal Study of 2002 (ELS:02), this study employs multiple regression to examine the effects of exit exams on student achievement and school completion. This study finds that exit exams as a whole do not have substantial effects on student achievement in mathematics,…

  5. The Effect of School Size on Exam Performance in Secondary Schools.

    ERIC Educational Resources Information Center

    Bradley, Steve; Taylor, Jim

    1998-01-01

    Examines the effects of school size on exam performance for pupils in their final year of compulsory education in England. Background information about English secondary schools and the determinants of exam performance are discussed along with a description of the variables used in the econometric analysis and their expected effects on exam…

  6. The Influence of a Pre-Reading Strategy on College Exam Scores: An Action Study

    ERIC Educational Resources Information Center

    Womack, Sid T.; Hanna, Shellie L.

    2010-01-01

    (Purpose) This study attempted to determine the effectiveness of an exam pre-reading strategy. (Methodology) It is an action research study that arose from a need in a particular class. A graduate class' scores on the first exam of the semester were unusually low. An instructor implemented a pre-reading strategy to determine if the scores would

  7. Assessment of the Assessment Tool: Analysis of Items in a Non-MCQ Mathematics Exam

    ERIC Educational Resources Information Center

    Khoshaim, Heba Bakr; Rashid, Saima

    2016-01-01

    Assessment is one of the vital steps in the teaching and learning process. The reported action research examines the effectiveness of an assessment process and inspects the validity of exam questions used for the assessment purpose. The instructors of a college-level mathematics course studied questions used in the final exams during the academic…

  8. Like Climbing Jacob's Ladder: An Art-Based Exploration of the Comprehensive Exam Process

    ERIC Educational Resources Information Center

    Shields, Sara Scott

    2015-01-01

    The comprehensive exam process is a rite of passage in the scholarly world, and as such the movements of this process often feel like a guarded secret to graduate students. As a PhD candidate, I left the comprehensive exam process feeling both initiated and inundated. This article is an attempt to uncover the secret that is the comprehensive exam…

  9. The ACT of Enrollment: The College Enrollment Effects of State-Required College Entrance Exam Testing

    ERIC Educational Resources Information Center

    Klasik, Daniel

    2013-01-01

    Since 2001 Colorado, Illinois, and Maine have all enacted policies that require high school juniors to take college entrance exams--the SAT or the ACT. One goal of these policies was to increase college enrollment based on the belief that requiring students to take these exams would make students more likely to consider college as a viable option.…

  10. Does Eating Breakfast Affect the Performance of College Students on Biology Exams?

    ERIC Educational Resources Information Center

    Phillips, Gregory W.

    2005-01-01

    This study examined the breakfast eating habits of 1,259 college students over an eleven year period to determine if eating breakfast had an impact upon their grade on a General Biology exam. The study determined that there was a significant difference in the performance on the exam with a higher percent of the participants, who had eaten…

  11. Verbal Final Exam in Introductory Biology Yields Gains in Student Content Knowledge and Longitudinal Performance

    ERIC Educational Resources Information Center

    Luckie, Douglas B.; Rivkin, Aaron M.; Aubry, Jacob R.; Marengo, Benjamin J.; Creech, Leah R.; Sweeder, Ryan D.

    2013-01-01

    We studied gains in student learning over eight semesters in which an introductory biology course curriculum was changed to include optional verbal final exams (VFs). Students could opt to demonstrate their mastery of course material via structured oral exams with the professor. In a quantitative assessment of cell biology content knowledge,…

  12. Do College Students Who Plan before Writing Score Better on Essay Exams?

    ERIC Educational Resources Information Center

    Gillis, M. K.; Olson, Mary W.

    A study examined the differences in the essay exam scores of college students who did no planning, some planning, or extensive planning before writing answers to questions on essay exams. Subjects, 100 undergraduate education students enrolled in reading methods classes and 37 graduate reading students enrolled in a psychology of reading class,…

  13. High School Exit Exams and Dropout in an Era of Increased Accountability

    ERIC Educational Resources Information Center

    Hemelt, Steven W.; Marcotte, Dave E.

    2013-01-01

    A key form of student-level accountability is the requirement for students to pass high school exit exams (HSEEs) in order to receive a diploma. In this paper, we examine the impact of HSEEs on dropout during a period when these exams became more common and rigorous. Further, we study whether offering alternate pathways to graduation for students

  14. The ACT of Enrollment: The College Enrollment Effects of State-Required College Entrance Exam Testing

    ERIC Educational Resources Information Center

    Klasik, Daniel

    2013-01-01

    Since 2001 Colorado, Illinois, and Maine have all enacted policies that require high school juniors to take college entrance exams--the SAT or the ACT. One goal of these policies was to increase college enrollment based on the belief that requiring students to take these exams would make students more likely to consider college as a viable option.

  15. Avoiding the Exam-Return Question "Wall"--Working with Your SERC Committee.

    ERIC Educational Resources Information Center

    Holmgren, Paul

    1992-01-01

    Describes the author's 10 years of experiences with the Student Exam Review Committee (SERC) that he formulated in response to intrinsic difficulties with examinations generated for large sections of college science courses. Discusses the selection of committee members, preexam input by the whole class, the committee's exam review process, and…

  16. The Use of a Comprehensive Multiple Choice Final Exam in the Macroeconomics Principles Course: An Assessment.

    ERIC Educational Resources Information Center

    Petrowsky, Michael C.

    This paper analyzes the results of a pilot study at Glendale Community College (Arizona) to assess the effectiveness of a comprehensive multiple choice final exam in the macroeconomic principles course. The "pilot project" involved the administration of a 50-question multiple choice exam to 71 students in three macroeconomics sections. The…

  17. Multiple-Choice Exam Question Order Influences on Student Performance, Completion Time, and Perceptions

    ERIC Educational Resources Information Center

    Pettijohn, Terry F., II; Sacco, Matthew F.

    2007-01-01

    We conducted 2 studies to investigate undergraduate performance, perceptions, and time required in completing sequentially ordered, randomly ordered, or reverse ordered exams in introductory psychology classes. Study 1 compared the outcomes and perceptions of students (N = 66) on 3 non-comprehensive multiple-choice exams which were sequentially,…

  18. Changes in Student Attributions Due to the Implementation of Central Exit Exams

    ERIC Educational Resources Information Center

    Oerke, Britta; Maag Merki, Katharina; Holmeier, Monika; Jager, Daniela J.

    2011-01-01

    The central aim of standardized exit exams is to motivate students and teachers to work harder on critical subject matters and thus increase student achievement. However, the effects of the implementation of central exams on student motivation have not been analyzed in a longitudinal section until now. In the present study, the consequences of…

  19. Improving Consistency in Large Laboratory Courses: A Design for a Standardized Practical Exam

    ERIC Educational Resources Information Center

    Chen, Xinnian; Graesser, Donnasue; Sah, Megha

    2015-01-01

    Laboratory courses serve as important gateways to science, technology, engineering, and mathematics education. One of the challenges in assessing laboratory learning is to conduct meaningful and standardized practical exams, especially for large multisection laboratory courses. Laboratory practical exams in life sciences courses are frequently…

  20. A Study of the Technological, Instructional, and Motivational Factors Affecting PHR Certification Exam Outcomes

    ERIC Educational Resources Information Center

    Bonner, David M.

    2012-01-01

    Although previous studies have considered the factors affecting other certification exam outcomes, they have not examined those that are related to performance on the Professional in Human Resources (PHR) exam. In response to that need, this study specifically investigates technology and training factors that affect self-efficacy and self-set…

  1. A Quantitative Analysis of Uncertainty in the Grading of Written Exams in Mathematics and Physics

    ERIC Educational Resources Information Center

    Hammer, Hugo Lewi; Habib, Laurence

    2016-01-01

    The most common way to grade students in courses at university and university college level is to use final written exams. The aim of final exams is generally to provide a reliable and a valid measurement of the extent to which a student has achieved the learning outcomes for the course. A source of uncertainty in grading students based on an exam…

  2. Investigating the Relationship between Faculty Cognitive Expectations about Learning Chemistry and the Construction of Exam Questions

    ERIC Educational Resources Information Center

    Sanabria-Rios, David; Bretz, Stacey Lowery

    2010-01-01

    We have investigated chemistry faculty's cognitive expectations about learning chemistry and their influence upon the construction of exam questions in a general chemistry curriculum. Faculty cognitive expectations for learning chemistry were measured using QUIMX. Learning objectives and exam questions for a year-long general chemistry sequence…

  3. FormScanner: Open-Source Solution for Grading Multiple-Choice Exams

    ERIC Educational Resources Information Center

    Young, Chadwick; Lo, Glenn; Young, Kaisa; Borsetta, Alberto

    2016-01-01

    The multiple-choice exam remains a staple for many introductory physics courses. In the past, people have graded these by hand or even flaming needles. Today, one usually grades the exams with a form scanner that utilizes optical mark recognition (OMR). Several companies provide these scanners and particular forms, such as the eponymous…

  4. What Does a Student Know Who Earns a Top Score on the Advanced Placement Chemistry Exam?

    ERIC Educational Resources Information Center

    Claesgens, Jennifer; Daubenmire, Paul L.; Scalise, Kathleen M.; Balicki, Scott; Gochyyev, Perman; Stacy, Angelica M.

    2014-01-01

    This paper compares the performance of students at a high-performing U.S. public school (n = 64) on the advanced placement (AP) chemistry exam to their performance on the ChemQuery assessment system. The AP chemistry exam was chosen because, as the National Research Council acknowledges, it is the "perceived standard of excellence and school

  5. Two-Stage Exams Improve Student Learning in an Introductory Geology Course: Logistics, Attendance, and Grades

    ERIC Educational Resources Information Center

    Knierim, Katherine; Turner, Henry; Davis, Ralph K.

    2015-01-01

    Two-stage exams--where students complete part one of an exam closed book and independently and part two is completed open book and independently (two-stage independent, or TS-I) or collaboratively (two-stage collaborative, or TS-C)--provide a means to include collaborative learning in summative assessments. Collaborative learning has been shown to…

  6. The Effects of High School Exit Exam Performance: New Evidence from Florida

    ERIC Educational Resources Information Center

    Clark, Damon; Martorell, Paco; Yang, Muzhe

    2009-01-01

    This paper presents new evidence on the effects of exit exam performance on high school persistence and completion as well as on college attendance using data on students from Florida. Specifically, they examine whether initial exit exam performance causes students to drop out of school, changes the likelihood of graduating from high school, and…

  7. Pick-N Multiple Choice-Exams: A Comparison of Scoring Algorithms

    ERIC Educational Resources Information Center

    Bauer, Daniel; Holzer, Matthias; Kopp, Veronika; Fischer, Martin R.

    2011-01-01

    To compare different scoring algorithms for Pick-N multiple correct answer multiple-choice (MC) exams regarding test reliability, student performance, total item discrimination and item difficulty. Data from six 3rd year medical students' end of term exams in internal medicine from 2005 to 2008 at Munich University were analysed (1,255 students,…

  8. Ethnic and Gender Differences in Advanced Placement Exam Performance: A Multiyear National Analysis

    ERIC Educational Resources Information Center

    Holmes, Maria Alexander

    2013-01-01

    Purpose: The purpose of this study was to analyze ethnic and gender differences in Advanced Placement (AP) exam performance of U.S. high school students. Specifically, the extent to which differences exist in overall AP exam performance scores within and between four ethnic groups (i.e., Asian, Black, Hispanic, and White) was investigated. Within…

  9. Assessment Drives Learning: The Effect of Central Exit Exams on Curricular Knowledge and Mathematical Literacy

    ERIC Educational Resources Information Center

    Jurges, Hendrik; Schneider, Kerstin; Senkbeil, Martin; Carstensen, Claus H.

    2012-01-01

    In this paper, we use data from the German PISA 2003 sample to study the effects of central exit examinations on student performance and student attitudes. Unlike earlier studies we use (i) a value-added measure to pin down the effect of central exit exams on learning in the last year before the exam and (ii) separate test scores for mathematical

  10. High School Exit Exam: Remediation for Another High-Stakes Test

    ERIC Educational Resources Information Center

    Misco, Thomas

    2010-01-01

    Now administered in 27 states and affecting 65 percent of all students, high school exit exams are gaining influence on teaching and learning because they constitute tests with extraordinarily high stakes. But what happens when students fail a high school exit exam? Few studies address the best way to remediate students in these situations.

  11. Effects of Failing a High School Exit Exam on Course Taking, Achievement, Persistence, and Graduation

    ERIC Educational Resources Information Center

    Reardon, Sean F.; Arshan, Nicole; Atteberry, Allison; Kurlaender, Michal

    2010-01-01

    The increasing use of state-mandated public high school exit exams is one manifestation of the current movement in U.S. public schooling toward more explicit standards of instruction and accountability. Exit exam requirements implicitly argue that raising the bar for graduation creates incentives both for students to work harder in school and for

  12. High-Stakes, Minimum-Competency Exams: How Competent Are They for Evaluating Teacher Competence?

    ERIC Educational Resources Information Center

    Goodman, Gay; Arbona, Consuelo; Dominguez de Rameriz, Romilia

    2008-01-01

    Increasingly, teacher educators recommend authentic, performance-related measures for evaluating teacher candidates. Nevertheless, more states are requiring teachers to pass high-stakes, minimum-competency exams. This study examined the relation between teacher candidate scores on authentic measures and their scores on certification exams required…

  13. Does Missing Classes Decelerate Student Exam Performance Progress? Empirical Evidence and Policy Implications

    ERIC Educational Resources Information Center

    Lin, Tin-Chun

    2014-01-01

    A total of 389 business students in undergraduate introductory microeconomics classes in spring 2007, 2009, and 2011, and fall 2012 participated in an exam performance progress study. Empirical evidence suggested that missing classes decelerates and hampers high-performing students' exam performance progress. Nevertheless, the evidence does…

  14. Entrance Exam Admission Policies on Ethnic Minorities and Equal Educational Rights for Minorities in China

    ERIC Educational Resources Information Center

    Weiwei, Lang

    2010-01-01

    In 1977, the Chinese government reinstated the national unified college entrance exam enrollment system. As a part of this system, the government also implemented preferential policies on the enrollment of minorities that authorized the increase or decrease of exam scores and enrollment cutoff points; the policies were therefore seen as…

  15. AK State Profile. Alaska: Alaska High School Graduation Qualifying Exam (HSGOE)

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper provides information about Alaska High School Graduation Qualifying Exam (HSGQE), a comprehensive standards-based exam. Its purpose is to meet a state mandate. A bill to remove the HSGQE as a graduation requirement by July 1, 2011 was presented to the state legislature as SB 109. However, it did not pass both houses of the legislature.…

  16. The ACS Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map I: General Chemistry

    ERIC Educational Resources Information Center

    Holme, Thomas; Murphy, Kristen

    2012-01-01

    To provide tools for programmatic assessment related to the use of ACS Exams in undergraduate chemistry courses, the ACS Exams Institute has built a content map that applies to the entire undergraduate curriculum. At the top two levels, the grain size of the content classification is large and spans the entire undergraduate curriculum. At the

  17. Investigating the Relationship between Faculty Cognitive Expectations about Learning Chemistry and the Construction of Exam Questions

    ERIC Educational Resources Information Center

    Sanabria-Rios, David; Bretz, Stacey Lowery

    2010-01-01

    We have investigated chemistry faculty's cognitive expectations about learning chemistry and their influence upon the construction of exam questions in a general chemistry curriculum. Faculty cognitive expectations for learning chemistry were measured using QUIMX. Learning objectives and exam questions for a year-long general chemistry sequence

  18. Validating the Use of AP® Exam Scores for College Course Placement. Research Report 2013-2

    ERIC Educational Resources Information Center

    Patterson, Brian F.; Ewing, Maureen

    2013-01-01

    The Advanced Placement Program® (AP®) was created to provide access to rigorous, college-level curricula to motivated and prepared high school students. This study evaluated whether the AP Exam scores from the summative exams associated with 10 courses were valid for the placement of students into higher-level college courses in the subject area…

  19. The Impact of Assessment Policy on Learning: Replacement Exams or Grade Dropping

    ERIC Educational Resources Information Center

    MacDermott, Raymond J.

    2013-01-01

    Instructors often debate the merits of alternate grading policies such as dropping the lowest exam or offering an additional exam to replace the lowest score. To date, there has been little research conducted on the impact of these policies on performance. In this study, the author investigates student performance in intermediate macroeconomics…

  20. Including an Exam P/1 Prep Course in a Growing Actuarial Science Program

    ERIC Educational Resources Information Center

    Wakefield, Thomas P.

    2014-01-01

    The purpose of this article is to describe the actuarial science program at our university and the development of a course to enhance students' problem solving skills while preparing them for Exam P/1 of the Society of Actuaries (SOA) and the Casualty Actuary Society (CAS). The Exam P/1 prep course, formally titled Mathematical Foundations of…

  1. Use of a Consumer-Grade Digital Camera to Archive Written Exams

    ERIC Educational Resources Information Center

    Maduro, Morris

    2006-01-01

    The use of a photocopier to archive exams consumes photocopier resources and generates a large amount of waste. As an alternative, I have been using a consumer-grade digital camera to document exams in an upper-division biology course. The approach is inexpensive and offers a number of advantages over photocopies. (Contains 2 figures.)

  2. Service Learning in Life-Span Developmental Psychology: Higher Exam Scores and Increased Empathy

    ERIC Educational Resources Information Center

    Lundy, Brenda L.

    2007-01-01

    This article describes research conducted to evaluate the impact of service learning on exam scores and emotional empathy in a life-span development course. Service learning was 1 of 3 project options offered in the course; others included an interview project and a research paper. With the exception of the first exam, scores were significantly…

  3. Lack of Follow-Up Exams after Failed School Vision Screenings: An Investigation of Contributing Factors

    ERIC Educational Resources Information Center

    Kimel, Linda S.

    2006-01-01

    Programs to facilitate professional eye exams after failed school vision screenings often are based on the assumption that funding and access to services are major obstacles to care. Despite such programs, many children do not receive professional exams. The purpose of this study was to identify additional barriers to follow-up eye care. School…

  4. Providing the Answers Does Not Improve Performance on a College Final Exam

    ERIC Educational Resources Information Center

    Glass, Arnold Lewis; Sinha, Neha

    2013-01-01

    In the context of an upper-level psychology course, even when students were given an opportunity to refer to text containing the answers and change their exam responses in order to improve their exam scores, their performance on these questions improved slightly or not at all. Four experiments evaluated competing explanations for the students'…

  5. The Road to Redemption: Reclaiming the Value in Assessment Retention Exams

    ERIC Educational Resources Information Center

    Stohlman, Trey

    2015-01-01

    A good assessment plan combines many direct and indirect measures to validate the collected data. One often controversial assessment measure comes in the form of retention exams. Although assessment retention exams may come with faults, others advocate for their inclusion in program assessment. Objective-based tests may offer insight to…

  6. Does Missing Classes Decelerate Student Exam Performance Progress? Empirical Evidence and Policy Implications

    ERIC Educational Resources Information Center

    Lin, Tin-Chun

    2014-01-01

    A total of 389 business students in undergraduate introductory microeconomics classes in spring 2007, 2009, and 2011, and fall 2012 participated in an exam performance progress study. Empirical evidence suggested that missing classes decelerates and hampers high-performing students' exam performance progress. Nevertheless, the evidence does

  7. Two-Stage Exams Improve Student Learning in an Introductory Geology Course: Logistics, Attendance, and Grades

    ERIC Educational Resources Information Center

    Knierim, Katherine; Turner, Henry; Davis, Ralph K.

    2015-01-01

    Two-stage exams--where students complete part one of an exam closed book and independently and part two is completed open book and independently (two-stage independent, or TS-I) or collaboratively (two-stage collaborative, or TS-C)--provide a means to include collaborative learning in summative assessments. Collaborative learning has been shown to

  8. The Impact of Assessment Policy on Learning: Replacement Exams or Grade Dropping

    ERIC Educational Resources Information Center

    MacDermott, Raymond J.

    2013-01-01

    Instructors often debate the merits of alternate grading policies such as dropping the lowest exam or offering an additional exam to replace the lowest score. To date, there has been little research conducted on the impact of these policies on performance. In this study, the author investigates student performance in intermediate macroeconomics

  9. Including an Exam P/1 Prep Course in a Growing Actuarial Science Program

    ERIC Educational Resources Information Center

    Wakefield, Thomas P.

    2014-01-01

    The purpose of this article is to describe the actuarial science program at our university and the development of a course to enhance students' problem solving skills while preparing them for Exam P/1 of the Society of Actuaries (SOA) and the Casualty Actuary Society (CAS). The Exam P/1 prep course, formally titled Mathematical Foundations of

  10. Effects of Failing a High School Exit Exam on Course Taking, Achievement, Persistence, and Graduation

    ERIC Educational Resources Information Center

    Reardon, Sean F.; Arshan, Nicole; Atteberry, Allison; Kurlaender, Michal

    2010-01-01

    The increasing use of state-mandated public high school exit exams is one manifestation of the current movement in U.S. public schooling toward more explicit standards of instruction and accountability. Exit exam requirements implicitly argue that raising the bar for graduation creates incentives both for students to work harder in school and for…

  11. The ACS Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map I: General Chemistry

    ERIC Educational Resources Information Center

    Holme, Thomas; Murphy, Kristen

    2012-01-01

    To provide tools for programmatic assessment related to the use of ACS Exams in undergraduate chemistry courses, the ACS Exams Institute has built a content map that applies to the entire undergraduate curriculum. At the top two levels, the grain size of the content classification is large and spans the entire undergraduate curriculum. At the…

  12. The Strategic Petroleum Reserve

    SciTech Connect

    Not Available

    1991-01-01

    The Strategic Petroleum Reserve program was set into motion by the 1975 Energy Policy and Conservation Act (EPCA). By 1990, 590 million barrels of oil had been placed in storage. Salt domes along the Gulf Coast offered ideal storage. Both sweet'' and sour'' crude oil have been acquired using various purchase options. Drawdown, sale, and distribution of the oil would proceed according to guidelines set by EPCA in the event of a severe energy supply disruption. (SM)

  13. Treatment planning systems for external whole brain radiation therapy: With and without MLC (multi leaf collimator) optimization

    NASA Astrophysics Data System (ADS)

    Budiyono, T.; Budi, W. S.; Hidayanto, E.

    2016-03-01

    Radiation therapy for brain malignancy is done by giving a dose of radiation to a whole volume of the brain (WBRT) followed by a booster at the primary tumor with more advanced techniques. Two external radiation fields given from the right and left side. Because the shape of the head, there will be an unavoidable hotspot radiation dose of greater than 107%. This study aims to optimize planning of radiation therapy using field in field multi-leaf collimator technique. A study of 15 WBRT samples with CT slices is done by adding some segments of radiation in each field of radiation and delivering appropriate dose weighting using a TPS precise plan Elekta R 2.15. Results showed that this optimization a more homogeneous radiation on CTV target volume, lower dose in healthy tissue, and reduced hotspots in CTV target volume. Comparison results of field in field multi segmented MLC technique with standard conventional technique for WBRT are: higher average minimum dose (77.25% ± 0:47%) vs (60% ± 3:35%); lower average maximum dose (110.27% ± 0.26%) vs (114.53% ± 1.56%); lower hotspot volume (5.71% vs 27.43%); and lower dose on eye lenses (right eye: 9.52% vs 18.20%); (left eye: 8.60% vs 16.53%).

  14. [Hypertrophy and coronary reserve].

    PubMed

    Motz, W; Scheler, S

    2008-12-01

    Left ventricular hypertrophy represents the structural mechanism of adaptation of the left ventricle as the answer of a chronic pressure overload in arterial hypertension. Initially an increment in left ventricular wall thickness occurs. In this stadium of "concentric hypertrophy" LV systolic wall stress, LV ejection fraction and myocardial oxygen consumption per weight unit myocardium remain unchanged. In the further time course of disease LV dilatation will be present. In this phase of "excentric hypertrophy" LV systolic wall stress and myocardial oxygen consumption per weight unit myocardium rise and LV ejection fraction decreases. Patients with arterial hypertension frequently complain of angina pectoris. Angina pectoris and the positive exercise tolerance test or the positive myocardial scintigraphy are the consequence of the impaired coronary flow reserve. The coronary flow reserve is diminished due to structural and functional changes of the coronary circulation. ACE-inhibitors and AT1-receptor blockers cause a significant improvement of coronary flow reserve and regression of both left ventricular hypertrophy and myocardial fibrosis. PMID:19085802

  15. Using the First Exam for Student Placement in Beginning Chemistry Courses

    NASA Astrophysics Data System (ADS)

    Mills, Pamela; Sweeney, William; Bonner, Sarah M.

    2009-06-01

    The first exam in a typical first-semester general chemistry course is used to identify students at risk of failing the course. The performance at Hunter College of 667 students on the first exam in general chemistry in seven different classes between fall 2000 and fall 2005 was correlated with the students' final score in the course. The correlation between the first exam score and the final course performance exclusive of the first exam was 0.73, a correlation coefficient (Pearson r value) higher than any commercially available diagnostic test. Logistic regression was performed on the same data set to generate a probability of success metric. Such an analysis can be used for student advising or placement. Similar results were found for eight first-semester general chemistry classes run at three other CUNY four-year colleges and at a large midwestern university, demonstrating the robustness of the correlation between the first exam and final course performance.

  16. 76 FR 63715 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS) Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer...) that an open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence...

  17. 76 FR 46897 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-03

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS), Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer...) that an open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence...

  18. 76 FR 56879 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS) Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer...) that an open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence...

  19. 76 FR 10942 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-28

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS), Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer...) that an open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence...

  20. 76 FR 37200 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-24

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS), Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer... open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence...

  1. 76 FR 22170 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-20

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS) Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer... open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence...

  2. 76 FR 6189 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-03

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS), Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer...) that an open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence...

  3. Predicting early academic success: HESI Admissions Assessment Exam.

    PubMed

    Knauss, Parry J; Willson, Pamela

    2013-01-01

    Student retention is a major challenge for undergraduate nursing programs, with the highest attrition occurring in the first year of the nursing curriculum. Admission criteria have been studied extensively but usually as related to end-of-program outcomes such as National Council Licensure Examination for Registered Nurses success. The purpose of this study was to examine the relationship between HESI Admission Assessment (A(2)) scores and academic performance in the 2 first-semester nursing courses of an associate degree program, Nursing-1 and Nursing-2. Findings indicated that the composite A(2) scores were strongly correlated with both Nursing-1 and Nursing-2 final course grades. Of the scores on the 4 component A(2) exams completed by the sample students (basic math skills, reading comprehension, vocabulary/general knowledge, and grammar), vocabulary/general knowledge scores had the strongest relationship to final course grades in both nursing courses. The authors concluded that A(2) scores facilitated evidence-based admission decisions. PMID:23566503

  4. Seamless insertion of real pulmonary nodules in chest CT exams

    NASA Astrophysics Data System (ADS)

    Pezeshk, Aria; Sahiner, Berkman; Zeng, Rongping; Wunderlich, Adam; Chen, Weijie; Petrick, Nicholas

    2014-03-01

    The availability of large medical image datasets is critical in many applications such as training and testing of computer aided diagnosis (CAD) systems, evaluation of segmentation algorithms, and conducting perceptual studies. However, collection of large repositories of clinical images is hindered by the high cost and difficulties associated with both the accumulation of data and establishment of the ground truth. To address this problem, we are developing an image blending tool that allows users to modify or supplement existing datasets by seamlessly inserting a real lesion extracted from a source image into a different location on a target image. In this study we focus on the application of this tool to pulmonary nodules in chest CT exams. We minimize the impact of user skill on the perceived quality of the blended image by limiting user involvement to two simple steps: the user first draws a casual boundary around the nodule of interest in the source, and then selects the center of desired insertion area in the target. We demonstrate examples of the performance of the proposed system on samples taken from the Lung Image Database Consortium (LIDC) dataset, and compare the noise power spectrum (NPS) of blended nodules versus that of native nodules in simulated phantoms.

  5. The new AP Physics exams: Integrating qualitative and quantitative reasoning

    NASA Astrophysics Data System (ADS)

    Elby, Andrew

    2015-04-01

    When physics instructors and education researchers emphasize the importance of integrating qualitative and quantitative reasoning in problem solving, they usually mean using those types of reasoning serially and separately: first students should analyze the physical situation qualitatively/conceptually to figure out the relevant equations, then they should process those equations quantitatively to generate a solution, and finally they should use qualitative reasoning to check that answer for plausibility (Heller, Keith, & Anderson, 1992). The new AP Physics 1 and 2 exams will, of course, reward this approach to problem solving. But one kind of free response question will demand and reward a further integration of qualitative and quantitative reasoning, namely mathematical modeling and sense-making--inventing new equations to capture a physical situation and focusing on proportionalities, inverse proportionalities, and other functional relations to infer what the equation ``says'' about the physical world. In this talk, I discuss examples of these qualitative-quantitative translation questions, highlighting how they differ from both standard quantitative and standard qualitative questions. I then discuss the kinds of modeling activities that can help AP and college students develop these skills and habits of mind.

  6. Multiple-choice exams: an obstacle for higher-level thinking in introductory science classes.

    PubMed

    Stanger-Hall, Kathrin F

    2012-01-01

    Learning science requires higher-level (critical) thinking skills that need to be practiced in science classes. This study tested the effect of exam format on critical-thinking skills. Multiple-choice (MC) testing is common in introductory science courses, and students in these classes tend to associate memorization with MC questions and may not see the need to modify their study strategies for critical thinking, because the MC exam format has not changed. To test the effect of exam format, I used two sections of an introductory biology class. One section was assessed with exams in the traditional MC format, the other section was assessed with both MC and constructed-response (CR) questions. The mixed exam format was correlated with significantly more cognitively active study behaviors and a significantly better performance on the cumulative final exam (after accounting for grade point average and gender). There was also less gender-bias in the CR answers. This suggests that the MC-only exam format indeed hinders critical thinking in introductory science classes. Introducing CR questions encouraged students to learn more and to be better critical thinkers and reduced gender bias. However, student resistance increased as students adjusted their perceptions of their own critical-thinking abilities. PMID:22949426

  7. Correlation Between Students' Dental Admission Test Scores and Performance on a Dental School's Competency Exam.

    PubMed

    Carroll, Alexander M; Schuster, Gregory M

    2015-11-01

    The aim of this study was to investigate whether there was a statistically significant positive correlation between dental students' Dental Admission Test (DAT) scores, particularly on the Perceptual Ability Test (PAT), and their performance on a dental school's competency exam. Scores from the written and clinical competency exam administered in the fall quarter of the fourth year of the curriculum at Midwestern University College of Dental Medicine-Arizona were compared to DAT scores of all 216 members of the graduating classes of 2012 and 2013. It was hypothesized that students who performed highly on one or more sections of the DAT would perform highly on the competency exam. Backward stepwise regression analyses were used to analyze the data. The results showed that the PAT scores were most strongly correlated with the competency exam scores and were a positive predictor for all three clinical sections of the exam (operative dentistry, periodontics, and endodontics). Positive predictors for the written portion of the exam were total DAT score for patient assessment and treatment planning and the DAT reading comprehension score for prosthodontics; there were no predictors for periodontics. The total variance explained by the results ranged from 4% to 15%. While statistically significant relationships were found between the students' PAT scores and clinical performance, DAT scores explained relatively little variance in the competency exam scores. According to these findings, neither the PAT nor any of the DAT components contributed to predicting these students' clinical performance. PMID:26522638

  8. The Elite Illusion: Achievement Effects at Boston and New York Exam Schools. NBER Working Paper No. 17264

    ERIC Educational Resources Information Center

    Abdulkadiroglu, Atila; Angrist, Joshua D.; Pathak, Parag A.

    2011-01-01

    Talented students compete fiercely for seats at Boston and New York exam schools. These schools are characterized by high levels of peer achievement and a demanding curriculum tailored to each district's highest achievers. While exam school students clearly do very well in school, the question of whether an exam school education adds value…

  9. Assessment of Validity, Reliability and Difficulty Indices for Teacher-Built Physics Exam Questions in First Year High School

    ERIC Educational Resources Information Center

    Jandaghi, Gholamreza

    2010-01-01

    The purpose of the research is to determine high school teachers' skill rate in designing exam questions in physics subject. The statistical population was all of physics exam shits for two semesters in one school year from which a sample of 364 exam shits was drawn using multistage cluster sampling. Two experts assessed the shits and by using

  10. 76 FR 10942 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-28

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  11. 76 FR 6190 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-03

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  12. 76 FR 37893 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  13. 76 FR 63716 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS) Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  14. 76 FR 37196 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-24

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  15. 76 FR 46897 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-03

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  16. 76 FR 56880 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS) Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  17. 76 FR 2196 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... Correspondence Exam Toll Free AGENCY: Internal Revenue Service (IRS) Treasury. ACTION: Notice of meeting. SUMMARY: An open meeting of the Taxpayer Advocacy Panel Small Business/ Self Employed Correspondence Exam Toll... Business/Self Employed Correspondence Exam Toll Free will be held Tuesday, February 22, 2011, at 9...

  18. A Comparison of Two Approaches for Assessing L2 Writing: Process-­Based and Impromptu Timed Writing Exams

    ERIC Educational Resources Information Center

    David, Virginia

    2016-01-01

    This study compares learners' writing in an impromptu, timed writing (ITW) exam and in a process-based, timed writing (PBTW) exam to investigate the differences between these two types of assessments. A secondary objective of this study is to examine the test takers' attitudes towards the two exams. Forty participants taking ESL writing classes…

  19. 76 FR 22170 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-20

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS) Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll Free Project Committee...

  20. 76 FR 17995 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ... Correspondence Exam Practitioner Engagement Project Committee AGENCY: Internal Revenue Service (IRS), Treasury... Employed Correspondence Exam Practitioner Engagement Project Committee will be conducted. The Taxpayer... Correspondence Exam Practitioner Engagement Project Committee will be held Monday, May 23, 2011 from 8 a.m. to...

  1. 76 FR 17996 - Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ... Correspondence Exam Toll Free Project Committee AGENCY: Internal Revenue Service (IRS) Treasury. ACTION: Notice... Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting... open meeting of the Taxpayer Advocacy Panel Small Business/Self Employed Correspondence Exam Toll...

  2. California High School Exit Exam Gets Real: Implications for the Class of 2006 and Beyond. EdSource Report

    ERIC Educational Resources Information Center

    Studier, Carol; Frey, Susan; Perry, Mary

    2006-01-01

    This EdSource report maps out the history and status of the California High School Exit Exam (CAHSEE) and addresses key issues surrounding the exam. It explains, for example, that the state superintendent has rejected postponing the exam or offering alternatives--a stance shared by many state leaders. But several lawsuits have been filed claiming…

  3. Assessment of Validity, Reliability and Difficulty Indices for Teacher-Built Physics Exam Questions in First Year High School

    ERIC Educational Resources Information Center

    Jandaghi, Gholamreza

    2010-01-01

    The purpose of the research is to determine high school teachers' skill rate in designing exam questions in physics subject. The statistical population was all of physics exam shits for two semesters in one school year from which a sample of 364 exam shits was drawn using multistage cluster sampling. Two experts assessed the shits and by using…

  4. Predictors of Academic Success for the National Board Dental Hygiene Examination and the Southern Regional Testing Agency Clinical Exam

    ERIC Educational Resources Information Center

    Efurd, Melissa G.

    2012-01-01

    The purpose for conducting this study was to investigate and describe the relationship between applicant criteria for a dental hygiene program and subsequent outcomes on credentialing exams: the National Board Dental Hygiene Exam and the Southern Regional Testing Agency clinical exam. Because admission criteria play a crucial role in applicant…

  5. Mechanical properties of intact single fibres from wild-type and MLC/mIgf-1 transgenic mouse muscle.

    PubMed

    Colombini, Barbara; Benelli, Giulia; Nocella, Marta; Musarò, Antonio; Cecchi, Giovanni; Bagni, M Angela

    2009-01-01

    The effects of overexpression of the local form of insulin like growth factor-1 (mIgf-1) on skeletal muscle were investigated by comparing the mechanical properties of single intact fibres from the flexor digitorum brevis of wild-type (WT) and (MLC/mIgf-1) transgenic mice (TG)at 21-24 degrees C. Isolated single fibres were clean enough to measure accurately the sarcomere length. The parameters investigated were: tetanic absolute and specific force, the force-velocity relationship, and the sarcomere length-tension relationship. In addition, we investigated the properties of the "static stiffness", a non-crossbridge Ca(2+)-dependent increase of fibre stiffness previously found in frog muscle. Both average cross-sectional area and tetanic force almost doubled in TG fibres, so that specific force was the same in both preparation: 312 +/- 20 and 344 +/- 34 kN m(-2) in WT and TG fibres, respectively. None of the relative force-velocity parameters was altered by Igf-1 overexpression, however, V(max) (8-10 l(0) s(-1)) was greater than previously reported in whole muscles. The sarcomere length-tension relationship was the same in TG and WT fibres showing the classical shape with a plateau region between 2.28 and 2.52 microm and a linear descending limb. The static stiffness was present in both WT and TG fibres and showed similar characteristics to that of frog skeletal muscle. In contrast to the other parameters, static stiffness in TG fibres was about 24% smaller than in WT fibres suggesting a possible effect of Igf-1 overexpression on its mechanism. PMID:19731048

  6. Model of international reserve pooling

    SciTech Connect

    Fischer, K.P.

    1985-01-01

    Holding foreign exchange in the form of reserves means foregoing income generating real investment. Thus, the careful management of reserves is required. Reserve pooling is an instrument to enhance this management. This study attempts to develop rigorously the theoretical foundations of the reserve pool. To develop the structure of the model the current account balance of non-oil-developing countries is assumed to follow a Wiener process with a negative drift. The stochastic time, called the hitting time, it takes for a cumulative balance to exhaust a given initial level of reserves is assumed to be the argument for the monetary authorities' utility function. Thus the decision on the management form and size of reserves can be made based on the mean and variance of this hitting time. The first order conditions obtained from a utility maximizing procedure determine the results obtained from the pooling model. This model predicts that reserve pooling is a Pareto optimal choice for the management of foreign exchange reserves for every member of a group of candidates.

  7. Operating Reserves and Variable Generation

    SciTech Connect

    Ela, E.; Milligan, M.; Kirby, B.

    2011-08-01

    This report tries to first generalize the requirements of the power system as it relates to the needs of operating reserves. It also includes a survey of operating reserves and how they are managed internationally in system operations today and then how new studies and research are proposing they may be managed in the future with higher penetrations of variable generation.

  8. 77 FR 40253 - Reserve Account

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-09

    ... publication as a Proposed Rule published in the Federal Register on April 5, 2007 (72 FR 16730-16731). The... regulation to change the Reserve Account for new construction for the Sections 514/516 Farm Labor Housing... final regulatory change will ensure that reserve accounts properly sized to meet the capital...

  9. Can Creativity Predict Cognitive Reserve?

    ERIC Educational Resources Information Center

    Palmiero, Massimiliano; Di Giacomo, Dina; Passafiume, Domenico

    2016-01-01

    Cognitive reserve relies on the ability to effectively cope with aging and brain damage by using alternate processes to approach tasks when standard approaches are no longer available. In this study, the issue if creativity can predict cognitive reserve has been explored. Forty participants (mean age: 61 years) filled out: the Cognitive Reserve…

  10. Teaching About Substance Abuse with Objective Structured Clinical Exams

    PubMed Central

    Parish, Sharon J; Ramaswamy, Megha; Stein, Melissa R; Kachur, Elizabeth K; Arnsten, Julia H

    2006-01-01

    BACKGROUND Although residents commonly manage substance abuse disorders, optimal approaches to teaching these specialized interviewing and intervention skills are unknown. OBJECTIVE We developed a Substance Abuse Objective Structured Clinical Exam (OSCE) to teach addiction medicine competencies using immediate feedback. In this study we evaluated OSCE performance, examined associations between performance and self-assessed interest and competence in substance abuse, and assessed learning during the OSCE. DESIGN Five-station OSCE, including different substance abuse disorders and readiness to change stages, administered during postgraduate year-3 ambulatory rotations for 2 years. PARTICIPANTS One hundred and thirty-one internal and family medicine residents. MEASUREMENTS Faculty and standardized patients (SPs) assessed residents' general communication, assessment, management, and global skills using 4-point scales. Residents completed a pre-OSCE survey of experience, interest and competence in substance abuse, and a post-OSCE survey evaluating its educational value. Learning during the OSCE was also assessed by measuring performance improvement from the first to the final OSCE station. RESULTS Residents performed better (P<.001) in general communication (mean ± SD across stations = 3.12 ± 0.35) than assessment (2.65 ± 0.32) or management (2.58 ± 0.44), and overall ratings were lowest in the contemplative alcohol abuse station (2.50 ± 0.83). Performance was not associated with residents' self-assessed interest or competence. Perceived educational value of the OSCE was high, and feedback improved subsequent performance. CONCLUSIONS Although internal and family medicine residents require additional training in specialized substance abuse skills, immediate feedback provided during an OSCE helped teach needed skills for assessing and managing substance abuse disorders. PMID:16704387

  11. The sensitivity of gamma-index method to the positioning errors of high-definition MLC in patient-specific VMAT QA for SBRT

    PubMed Central

    2014-01-01

    Background To investigate the sensitivity of various gamma criteria used in the gamma-index method for patient-specific volumetric modulated arc therapy (VMAT) quality assurance (QA) for stereotactic body radiation therapy (SBRT) using a flattening filter free (FFF) photon beam. Methods Three types of intentional misalignments were introduced to original high-definition multi-leaf collimator (HD-MLC) plans. The first type, referred to Class Out, involved the opening of each bank of leaves. The second type, Class In, involved the closing of each bank of leaves. The third type, Class Shift, involved the shifting of each bank of leaves towards the ground. Patient-specific QAs for the original and the modified plans were performed with MapCHECK2 and EBT2 films. The sensitivity of the gamma-index method using criteria of 1%/1 mm, 1.5%/1.5 mm, 1%/2 mm, 2%/1 mm and 2%/2 mm was investigated with absolute passing rates according to the magnitudes of MLCs misalignments. In addition, the changes in dose-volumetric indicators due to the magnitudes of MLC misalignments were investigated. The correlations between passing rates and the changes in dose-volumetric indicators were also investigated using Spearman’s rank correlation coefficient (γ). Results The criterion of 2%/1 mm was able to detect Class Out and Class In MLC misalignments of 0.5 mm and Class Shift misalignments of 1 mm. The widely adopted clinical criterion of 2%/2 mm was not able to detect 0.5 mm MLC errors of the Class Out or Class In types, and also unable to detect 3 mm Class Shift errors. No correlations were observed between dose-volumetric changes and gamma passing rates (γ < 0.8). Conclusions Gamma criterion of 2%/1 mm was found to be suitable as a tolerance level with passing rates of 90% and 80% for patient-specific VMAT QA for SBRT when using MapCHECK2 and EBT2 film, respectively. PMID:25070065

  12. SU-E-T-282: Remove Field-Size Limitation Using the Combination of Collimator Rotation and Jaw Tracking with MLC Aperture

    SciTech Connect

    Shiu, A; Chiu, R; Cumming, D; Chung, E; Ragab, O; Cui, G

    2014-06-01

    Purpose: this study is to investigate the use of variable-collimators and/or collimator-rotation to overcome the field-size limitation on TrueBeamSTX. Methods: The maximum static field-size is 22- × 40-cm for TrueBeamSTX and 40- × 40-cm for Trilogy. Maximum displacement between adjacent leaf ends at a single carriage position is 15-cm for TBSTX and 14-cm for Trilogy. Our current practice for IMRT treatment at Trilogy is as follows, if MLC leaves travel more than 13.5 cm in the MLC traveling direction, the treatment fields will be split at isocenter to two groups of IMRT fields to cover the large tumors. However, TrueBeamSTX is not limited in this way because the jaws can track each segments of the MLC aperture. Radiation treatment plans for ten patients (different tumor sites) treated at Trilogy with one dimension of the field is greater than 22 cm and the other dimension is less than or equal to 22 cm. All the plans will be converted with jaws tracking each segment's MLC aperture. If necessary, the collimator rotation will also be applied for the planning. Comparison of the converted plans with the original clinical plans will be evaluated and based on the following criterion: (1) tumor coverage; (2) dose sparing to the critical structures; and (3) treatment time. Results: The tumor coverage is compatible between two plans. The dose of critical structures was evaluated in the cumulative DVH for spinal cord, parotids, and brainstem at V20 and V5. In all patients, the maximum reduction in V20 was never more than 5% and was typically less than 1%. In V5, the maximum reduction was 10% and 3% respectively. The significant difference can be found in using the variable collimator to shorten the treatment time. Conclusion: We conclude that we will use the variable-collimator for all IMRT cases on TrueBeamSTX and as a potential backup machine for Trilogy.

  13. SU-E-T-569: Evaluation of VMAT Plans Generated with HD120 and Millennium 120 MLC Between Two Matched Linacs

    SciTech Connect

    Cui, G; Ballas, L; Chang, E; Chung, E; Chiu, R; Cummings, D; Shiu, A

    2014-06-01

    Purpose: To evaluate VMAT treatment plans generated with HD120 MLC and Millennium 120 MLC between two matched linacs and to determine if one can back up the other. Methods: The 6x photon beams are matched for our Varian TrueBeam STx and Trilogy linacs, which are equipped with HD120 MLC and Millennium 120 MLC, respectively. Three prostate and three brain VMAT plans were used for the evaluation. Five plans (three prostate and two brain plans) were originally generated with the TrueBeam STx and re-computed with the Trilogy. One brain plan was evaluated the other way around. For each plan, the PTV coverage of V95 was made the same between two linacs. The dosimetric differences associated with the plans were compared using: 1) Percentage mean dose differences to the PTV, 2) Homogeneity index, HI = (Dmax − Dmin)/Dmean for the PTV. For prostate plans, the mean dose differences to the rectum were evaluated. While for brain plans, the percentage max dose differences to the lenses (left and right lens) were evaluated. Results: For three prostate plans, the average of the percentage mean dose differences to the PTV was 0.5 ± 0.1% and the HI was 0.1 ± 0.0%. The average of the percentage mean dose difference to the rectum was 3.5 ± 0.5%. For three brain plans, the average of the percentage mean dose differences to the PTV was 0.2 ± 1.1% and the HI was 0.2 ± 0.1%. The average of the percentage max dose differences to the lenses was 22.9 ± 4.0%. Conclusion: For prostate VMAT plans, changing the treatment from the TrueBeam STx to the Trilogy does not necessarily need re-optimization. But for brain plans, in order to minimize dose to the lenses, it is recommended to re-optimize the plan if changing the treatment between these two linacs.

  14. Potential Danger in Pre-populating Exam Note Sheets with Formulas

    NASA Astrophysics Data System (ADS)

    McCaskey, Timothy L.

    2015-09-01

    In previous work, I allowed students in my introductory physics course to write note sheets to prepare for exams, and I analyzed the contents as a way of determining what students saw as important in my course. In the present study, I tried a new note sheet approach where I supplied some equations for their notes in advance, thinking that doing so would focus students on other important conceptual aspects of the course. In all cases, I gave a brief survey to get student perspectives on their exam preparation. In addition, I introduced an online pre-exam forum asking students to respond to two short questions about how they might prepare their notes for the exam.

  15. A Comparison of In-Class Quizzes vs. Online Quizzes on Student Exam Performance.

    ERIC Educational Resources Information Center

    Derouza, Eros; Fleming, Matthew

    2003-01-01

    Compared undergraduates who took online quizzes using Mallard with students taking traditional paper-and-pencil quizzes. Found that Mallard students performed significantly better on in-class exams than non-Mallard students. (EV)

  16. Expedition 35/36 Final Exams - Duration: 4 minutes, 50 seconds.

    NASA Video Gallery

    Three Expedition 35/36 crew members prepare for their final exams in their Sokol launch and entry suits at the Gagarin Cosmonaut Training Center in Star City, Russia. NASA astronaut Chris Cassidy a...

  17. Overseas recruits' English exam: a proper safety check or red tape?

    PubMed

    Kendall-Raynor, Petra

    2016-05-01

    The director of workforce at a trust that struggles to recruit nurses from outside the European Union because many fail to pass the required English test decided to sit the exam himself. PMID:27154089

  18. Expedition 32 Final Soyuz Qualification Exams - Duration: 4 minutes, 35 seconds.

    NASA Video Gallery

    Expedition 32 Flight Engineers Suni Williams, Yuri Malenchenko and Aki Hoshide take their final Soyuz systems qualification exams at the Gagarin Cosmonaut Training Center in Star City, Russia. The ...

  19. [THE STUDY OF THE SEVERITY OF EXAM STRESS AND FACTORS WHICH DETERMINE IT IN OLDER SCHOOLCHILDREN].

    PubMed

    Bobrisheva-Pushkina, N D; Kuznetsova, L Yu; Popova, O L; Silaev, A A

    2015-01-01

    The study was performed with the help of a questionnaire of views of senior schoolchildren about the objectivity and stressfulness of various forms of the control of knowledge, the level of stress in the exams and measures for its reduction. 53.4% out of the students assess their knowledge in this area as insufficient. The most objective form of the control students consider an oral exam, the least stressful--blank testing. After passing the exams in class 9 we observed the evident reduction of representations of the objectivity of test forms of control. The necessity of the activization of educational work with students on the issues of prevention of exam stress and methodological work on perfection of the organization and content of the forms of Knowledge control is showed. PMID:26302564

  20. Introducing Computer-Based Testing in High-Stakes Exams in Higher Education: Results of a Field Experiment

    PubMed Central

    Boevé, Anja J.; Meijer, Rob R.; Albers, Casper J.; Beetsma, Yta; Bosker, Roel J.

    2015-01-01

    The introduction of computer-based testing in high-stakes examining in higher education is developing rather slowly due to institutional barriers (the need of extra facilities, ensuring test security) and teacher and student acceptance. From the existing literature it is unclear whether computer-based exams will result in similar results as paper-based exams and whether student acceptance can change as a result of administering computer-based exams. In this study, we compared results from a computer-based and paper-based exam in a sample of psychology students and found no differences in total scores across the two modes. Furthermore, we investigated student acceptance and change in acceptance of computer-based examining. After taking the computer-based exam, fifty percent of the students preferred paper-and-pencil exams over computer-based exams and about a quarter preferred a computer-based exam. We conclude that computer-based exam total scores are similar as paper-based exam scores, but that for the acceptance of high-stakes computer-based exams it is important that students practice and get familiar with this new mode of test administration. PMID:26641632

  1. Introducing Computer-Based Testing in High-Stakes Exams in Higher Education: Results of a Field Experiment.

    PubMed

    Boevé, Anja J; Meijer, Rob R; Albers, Casper J; Beetsma, Yta; Bosker, Roel J

    2015-01-01

    The introduction of computer-based testing in high-stakes examining in higher education is developing rather slowly due to institutional barriers (the need of extra facilities, ensuring test security) and teacher and student acceptance. From the existing literature it is unclear whether computer-based exams will result in similar results as paper-based exams and whether student acceptance can change as a result of administering computer-based exams. In this study, we compared results from a computer-based and paper-based exam in a sample of psychology students and found no differences in total scores across the two modes. Furthermore, we investigated student acceptance and change in acceptance of computer-based examining. After taking the computer-based exam, fifty percent of the students preferred paper-and-pencil exams over computer-based exams and about a quarter preferred a computer-based exam. We conclude that computer-based exam total scores are similar as paper-based exam scores, but that for the acceptance of high-stakes computer-based exams it is important that students practice and get familiar with this new mode of test administration. PMID:26641632

  2. Impact of implementing an EMR on physical exam documentation by ambulance personnel

    PubMed Central

    Katzer, R.; Barton, D.J.; Adelman, S.; Clark, S.; Seaman, E.L.; Hudson, K.B.

    2012-01-01

    Objectives Georgetown University has a student run Emergency Medical Services (EMS) organization with over 100 emergency medical technicians (EMTs). We set out to determine whether implementing an electronic patient care report (ePCR) system was associated with improved physical exam documentation. Methods This study evaluated documentation of the physical exam on prehospital patient care reports (PCRs). An ePCR system was implemented. ePCR documentation was compared to that of the previously used paper PCRs. This study looked retrospectively at 154 PCRs. 77 were hand written PCRs from before the electronic system. The PCRs involved chief complaints that were primarily respiratory, neurologic, or both. 77 ePCRs of matching chief complaint categories were used for comparison. Each chart was reviewed for completion of certain physical exam findings. The mean percentage of documented components from the ePCRs was compared to that of the hand written PCRs. The null hypothesis was that the absolute increase in the mean was not more than 20 percent. The two exclusion criteria were PCRs completed by study investigators after the design of the project and partially or completely missing PCRs. Results The absolute increase in mean physical exam component documentation was 36% (95% CI = 29–43%). A weighted kappa of 0.894 showed very good agreement between chart reviewers. Conclusions This study rejected the null hypothesis that the ePCR system was associated with a mean increase of no more than 20%. It observed increase in physical exam documentation. Limitations of this study included the inability to determine whether documentation of physical exam findings reflected performance of the physical exam, and what components of the ePCR system bundle were responsible for the increase in physical exam component documentation. PMID:23646077

  3. FormScanner: Open-Source Solution for Grading Multiple-Choice Exams

    NASA Astrophysics Data System (ADS)

    Young, Chadwick; Lo, Glenn; Young, Kaisa; Borsetta, Alberto

    2016-01-01

    The multiple-choice exam remains a staple for many introductory physics courses. In the past, people have graded these by hand or even flaming needles. Today, one usually grades the exams with a form scanner that utilizes optical mark recognition (OMR). Several companies provide these scanners and particular forms, such as the eponymous "Scantron." OMR scanners combine hardware and software—a scanner and OMR program—to read and grade student-filled forms.

  4. Classification and analysis of multiple sclerosis lesions in spin-echo MR exams

    NASA Astrophysics Data System (ADS)

    Mitchell, Ross; Karlik, Stephen J.; Lee, Donald H.; Fenster, Aaron

    1994-09-01

    The high resolution and excellent soft tissue contrast of Magnetic Resonance Imaging (MRI) have enabled direct, non- invasive visualization of Multiple Sclerosis (MS) lesions in vivo. This has allowed quantification of changes in the appearance of lesions in MR exams to be used as a measure of disease state. Nevertheless, accurate quantification techniques are subject to inter- and intra-operator variability, which may hinder monitoring of disease progression. We have developed a computer program to aid an experienced operator in the quantification of MS lesions in spin-echo MR exams. Assisted and manual quantification were used to study inter-operator and intra-operator variability under known conditions in exams of a test phantom, and under clinical conditions in 1.5T and 0.5T exams of an MS patient. Results of the phantom study show that accuracy was improved by assisted quantification. The patient exam results indicate that assisted quantification reduced both inter-operator and intra-operator variability, while quantification in 0.5T exams reduced the variability of manual quantification, but had no significant effect upon assisted quantification. Application of assisted quantification to the analysis and visualization of two large periventricular lesions reveals subtle changes over time in the internal composition of these apparently static lesions.

  5. Test Anxiety Levels of Board Exam Going Students in Tamil Nadu, India

    PubMed Central

    Ann Mary, Revina; Marslin, Gregory; Franklin, Gregory; Sheeba, Caroline J.

    2014-01-01

    The latest report by the National Crime Records Bureau has positioned Tamil Nadu as the Indian state with highest suicide rate. At least in part, this is happening due to exam pressure among adolescents, emphasizing the imperative need to understand the pattern of anxiety and various factors contributing to it among students. The present study was conducted to analyze the level of state anxiety among board exam attending school students in Tamil Nadu, India. A group of 100 students containing 50 boys and 50 girls from 10th and 12th grades participated in the study and their state anxiety before board exams was measured by Westside Test Anxiety Scale. We found that all board exam going students had increased level of anxiety, which was particularly higher among boys and 12th standard board exam going students. Analysis of various demographic variables showed that students from nuclear families presented higher anxiety levels compared to their desired competitive group. Overall, our results showing the prevalence of state anxiety among board exam going students in Tamil Nadu, India, support the recent attempt taken by Tamil Nadu government to improve student's academic performance in a healthier manner by appointing psychologists in all government schools. PMID:25143938

  6. Sleep Quality during Exam Stress: The Role of Alcohol, Caffeine and Nicotine

    PubMed Central

    Zunhammer, Matthias; Eichhammer, Peter; Busch, Volker

    2014-01-01

    Academic exam stress is known to compromise sleep quality and alter drug consumption in university students. Here we evaluated if sleeping problems and changes in legal drug consumption during exam stress are interrelated. We used the Pittsburgh Sleep Quality Index (PSQI) to survey sleep quality before, during, and after an academic exam period in 150 university students in a longitudinal questionnaire study. Self-reports of alcohol, caffeine, and nicotine consumption were obtained. The Perceived Stress Questionnaire (PSQ-20) was used as a measure of stress. Sleep quality and alcohol consumption significantly decreased, while perceived stress and caffeine consumption significantly increased during the exam period. No significant change in nicotine consumption was observed. In particular, students shortened their time in bed and showed symptoms of insomnia. Mixed model analysis indicated that sex, age, health status, as well as the amounts of alcohol and caffeine consumed had no significant influence on global sleep quality. The amount of nicotine consumed and perceived stress were identified as significant predictors of diminished sleep quality. Nicotine consumption had a small-to-very-small effect on sleep quality; perceived stress had a small-to-moderate effect. In conclusion, diminished sleep quality during exam periods was mainly predicted by perceived stress, while legal drug consumption played a minor role. Exam periods may pose an interesting model for the study of stress-induced sleeping problems and their mechanisms. PMID:25279939

  7. Electronic reserves: copyright and permissions.

    PubMed

    Graves, K J

    2000-01-01

    Electronic reserves present a new service option for libraries to provide needed materials during hours that the library is not open and to user groups located some distance from library collections. Possible changes to current copyright law and publishers permissions policies have delayed the development of electronic reserves in many libraries. This paper reviews the current state of electronic reserves materials in the publishing and library communities and presents the results of a survey of publishers to determine permissions policies for electronic materials. Issues of concern to both libraries and publishers are discussed. PMID:10658960

  8. Integrity of Disposable Nitrile Exam Gloves Exposed to Simulated Movement

    PubMed Central

    Phalen, Robert N.; Wong, Weng Kee

    2011-01-01

    Every year, millions of health care, first responder, and industry workers are exposed to chemical and biological hazards. Disposable nitrile gloves are a common choice as both a chemical and physical barrier to these hazards, especially as an alternative to natural latex gloves. However, glove selection is complicated by the availability of several types or formulations of nitrile gloves, such as low-modulus, medical-grade, low-filler, and cleanroom products. This study evaluated the influence of simulated movement on the physical integrity (i.e., holes) of different nitrile exam glove brands and types. Thirty glove products were evaluated out-of-box and after exposure to simulated whole-glove movement for 2 hr. In lieu of the traditional 1-L water-leak test, a modified water-leak test, standardized to detect a 0.15 ± 0.05 mm hole in different regions of the glove, was developed. A specialized air inflation method simulated bidirectional stretching and whole-glove movement. A worst-case scenario with maximum stretching was evaluated. On average, movement did not have a significant effect on glove integrity (chi-square; p=0.068). The average effect was less than 1% between no movement (1.5%) and movement (2.1%) exposures. However, there was significant variability in glove integrity between different glove types (p ≤ 0.05). Cleanroom gloves, on average, had the highest percentage of leaks, and 50% failed the water-leak test. Low-modulus and medical-grade gloves had the lowest percentages of leaks, and no products failed the water-leak test. Variability in polymer formulation was suspected to account for the observed discrepancies, as well as the inability of the traditional 1-L water-leak test to detect holes in finger/thumb regions. Unexpectedly, greater than 80% of the glove defects were observed in the finger and thumb regions. It is recommended that existing water-leak tests be re-evaluated and standardized to account for product variability. PMID:21476169

  9. Integrity of disposable nitrile exam gloves exposed to simulated movement.

    PubMed

    Phalen, Robert N; Wong, Weng Kee

    2011-05-01

    Every year, millions of health care, first responder, and industry workers are exposed to chemical and biological hazards. Disposable nitrile gloves are a common choice as both a chemical and physical barrier to these hazards, especially as an alternative to natural latex gloves. However, glove selection is complicated by the availability of several types or formulations of nitrile gloves, such as low-modulus, medical grade, low filler, and cleanroom products. This study evaluated the influence of simulated movement on the physical integrity (i.e., holes) of different nitrile exam glove brands and types. Thirty glove products were evaluated out-of-box and after exposure to simulated whole-glove movement for 2 hr. In lieu of the traditional 1 L water-leak test, a modified water-leak test, standardized to detect a 0.15 ± 0.05 mm hole in different regions of the glove, was developed. A specialized air inflation method simulated bidirectional stretching and whole-glove movement. A worst-case scenario with maximum stretching was evaluated. On average, movement did not have a significant effect on glove integrity (chi-square; p=0.068). The average effect was less than 1% between no movement (1.5%) and movement (2.1%) exposures. However, there was significant variability in glove integrity between different glove types (p≤0.05). Cleanroom gloves, on average, had the highest percentage of leaks, and 50% failed the water-leak test. Low-modulus and medical grade gloves had the lowest percentages of leaks, and no products failed the water-leak test. Variability in polymer formulation was suspected to account for the observed discrepancies, as well as the inability of the traditional 1 L water-leak test to detect holes in finger/thumb regions. Unexpectedly, greater than 80% of the glove defects were observed in the finger and thumb regions. It is recommended that existing water-leak tests be re-evaluated and standardized to account for product variability. PMID:21476169

  10. Impact of MLC leaf width on volumetric-modulated arc therapy planning for head and neck cancers.

    PubMed

    Lafond, Caroline; Chajon, Enrique; Devillers, Anne; Louvel, Guillaume; Toublanc, Sandra; Olivier, Mickael; Simon, Antoine; De Crevoisier, Renaud; Manens, Jean-Pierre

    2013-01-01

    This dosimetric study investigated the impact of multileaf collimators (MLC) leaf width in volumetric-modulated arc therapy (VMAT) for head and neck cancers (HNC), either with a "standard" simultaneously integrated boost technique (S-SIB) or with a "dose painting" SIB technique (DP-SIB). HNC patients were planned either with an S-SIB comprising three dose levels, from 56 to 70 Gy (16 patients), or with a DP-SIB comprising five dose levels, from 56 to 84 Gy (8 patients), in 35 fractions. Two VMAT plans were calculated for each SIB technique using two Elekta MLCs: MLCi2 with 10 mm leaf width and Beam Modulator (BM) with 4 mm leaf width. Dose distributions were evaluated by comparing doses on PTVs, main OARs, and healthy tissue, and by comparing conformation indexes. Treatment efficiencies were evaluated by comparing the number of monitor units and the number of needed arcs. Comparisons of the two MLCs depending on the two SIB techniques showed: i) Regarding PTVs: Dmean and D2% on lower doses PTV decreased respectively by 0.5 Gy (p = 0.01) and 0.9 Gy (p = 0.01) with BM than with MLCi2 for S-SIB; no significant difference was found for DP-SIB;ii) Regarding OARs: for spinal cord and brainstem, D2% decreased respectively by 1.2 Gy (p = 0.03) and 4.2 Gy (p = 0.04) with BM than with MLCi2 for S-SIB; for controlateral parotid, D50% decreased by 1.5 Gy (p = 0.01) with BM than with MLCi2 for S-SIB; iii) Regarding treatment efficiency: the number of monitor units was 44% (p = 0.00) and 51% (p = 0.01) higher with BM for S-SIB and DP-SIB, respectively. Two arcs were more frequently needed with BM to reach an acceptable dose distribution. This study demonstrated that Beam Modulator (4 mm leaf width) and MLCi2 (10 mm leaf width) MLCs from Elekta provided satisfactory dose distributions for treatment delivery with VMAT technique for complex HNC cases with standard and dose painting prescriptions. OAR sparing was better with BM, mainly for brainstem and spinal cord. However, delivery efficiency of VMAT plans was better with MLCi2. PMID:24257269

  11. 24 CFR 598.500 - Indian reservations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 3 2013-04-01 2013-04-01 false Indian reservations. 598.500... Rules § 598.500 Indian reservations. (a) An area within an Indian reservation (as defined in section 168... Empowerment Zone by State and local governments. An area completely within an Indian reservation may...

  12. 24 CFR 598.500 - Indian reservations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 3 2012-04-01 2012-04-01 false Indian reservations. 598.500... Rules § 598.500 Indian reservations. (a) An area within an Indian reservation (as defined in section 168... Empowerment Zone by State and local governments. An area completely within an Indian reservation may...

  13. 7 CFR 25.500 - Indian reservations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false Indian reservations. 25.500 Section 25.500 Agriculture... § 25.500 Indian reservations. (a) An area in an Indian reservation shall be treated as nominated by a... paragraph (a) of this section, a reservation governing body must be the governing body of an Indian...

  14. 7 CFR 25.500 - Indian reservations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Indian reservations. 25.500 Section 25.500 Agriculture... § 25.500 Indian reservations. (a) An area in an Indian reservation shall be treated as nominated by a... paragraph (a) of this section, a reservation governing body must be the governing body of an Indian...

  15. 24 CFR 598.500 - Indian reservations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 3 2014-04-01 2013-04-01 true Indian reservations. 598.500 Section....500 Indian reservations. (a) An area within an Indian reservation (as defined in section 168(j)(6) if... Zone by State and local governments. An area completely within an Indian reservation may be...

  16. 7 CFR 25.500 - Indian reservations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Indian reservations. 25.500 Section 25.500 Agriculture... § 25.500 Indian reservations. (a) An area in an Indian reservation shall be treated as nominated by a... paragraph (a) of this section, a reservation governing body must be the governing body of an Indian...

  17. Veterinary Science Students, Center Changing a Reservation

    ERIC Educational Resources Information Center

    Blackwater, Jasmine

    2011-01-01

    Kayenta is a rural community located in northeastern Arizona on a Navajo reservation. On the reservation, many families rely on their livestock for income, and as a result, many reservation high school students show a great interest in agricultural education. Having livestock on the reservation is not just a source of income, but also part of a…

  18. Online Course Reserves and Graduate Student Satisfaction

    ERIC Educational Resources Information Center

    Isenberg, Laurie

    2006-01-01

    This study assesses student satisfaction with online course reserves in a graduate environment. Surveys indicated that students prefer online course reserves over in-library print course reserves. Pre-printed course readers are preferred when the purchase price of the reader is less than the cost of printing online reserves. Graduate students are

  19. Advanced Placement® Exam Participation: Is AP® Exam Participation and Performance Related to Choice of College Major? Research Report No. 2011-6

    ERIC Educational Resources Information Center

    Mattern, Krista D.; Shaw, Emily J.; Ewing, Maureen

    2011-01-01

    Previous research has found a positive relationship between AP® participation and performance with various college outcomes. Building on this work, the current study investigated the relationship between AP participation and performance with choice of college major. Specifically, this study examined whether students who take an AP Exam in a…

  20. Peer-led instruction for a qualifying exam preparatory course or: How I learned to stop worrying and love the PhD Qualifying Exam

    NASA Astrophysics Data System (ADS)

    Christensen, Warren; Engelhardt, Larry

    2006-04-01

    In the spring of 2004, the authors were charged with the task of creating and administering a qualifying exam preparation curriculum that would strive to assist graduate students studying for their comprehensive physics exam. We incorporated many pedagogical techniques that have been proven effective at nearly all levels of instruction by leading researchers in the field of physics education. Our primary focus was on peer-led instruction and time-on-task doing actual problems from previous qualifying exams. After a brief but precise lecture covering essential ideas over a particular subject matter, students spend most of class time working in small groups and presenting worked problems at the board. At all times, the focus was on student explanations concerning the fundamental concepts behind a specific problem, as well as contemplating variations to broaden understanding and challenge students to think on their feet. We found that students who attended and participated regularly in class could be correlated with those students who achieved high marks on the exam.